Search

The constant dynamism within the oil industry associated with the need for new technologies in terms of production and disposal of products were fundamental for the increase of studies about the use of underground caverns in salt rocks as an alternative for the storage of petroleum products. Salt rock is particularly useful for storage because of its low cost, low permeability, and its healing potential when compared to other rocks, including granite, mud, and basalt. The opening process and subsequent development of these cavities are complex activities and the variables involved in the process play a crucial role during the entire operation. In this sense, the present work aims to identify, through the PCA (Principal Component Analysis) statistical tool, the variables that most influence the process of opening a salt cavern by dissolution. For this, numerical simulations of the dissolution mining process for opening a cavern under typical conditions of water injection into a salt rock using the software SALGAS were developed considering different methods of saline water circulation, after that, the variables injection temperature, injection rate, radius, volume, pump power, cumulative energy, tubing loss, produced brine, pump pressure, injection pressure, and salt dissolution factor were interpreted using the multivariate statistical tool through software PAST. For the simulations generated, the results with the statistical tool were satisfactory, it was found that the brine injection rate contributes significantly to the process, in terms of x-axis, directly influencing the behavior of other variables, the temperature have a great importance to the y-axis. Regarding the total variability of the data, more than 97% of these could be represented in terms of the first two components for both scenarios studied.

Enhanced coagulation experiments have been carried out on the co-treatment of mine water from the Jamadoba colliery and natural organic matter (NOM)-containing surface water from the nearby Damodar River (Jharkhand, India). Mixing of near-neutral pH mine water with surface water substantially reduced the reactive portion of the NOM in the surface water by enhancing the coagulation process, using alum as a coagulant. The hardness and ionic moieties in the mine water improved the effectiveness of the alum in reducing the NOM concentrations. The interactive effects of differing pH, mixing proportion, and coagulant dose, were optimised using a statistical tool. Experimental results showed that the best conditions for removing the reactive part of NOM were pH 6, 3.5 mg/L of coagulant, and a mix ratio of 0.76 (mine water:surface water). The results suggested that mixing of this mine water with river water would be an appropriate way to maximise the removal of the reactive part of NOM prior to disinfection and would provide good quality drinking water., Enhanced coagulation experiments have been carried out on the co-treatment of mine water from the Jamadoba colliery and natural organic matter (NOM)-containing surface water from the nearby Damodar River (Jharkhand, India). Mixing of near-neutral pH mine water with surface water substantially reduced the reactive portion of the NOM in the surface water by enhancing the coagulation process, using alum as a coagulant. The hardness and ionic moieties in the mine water improved the effectiveness of the alum in reducing the NOM concentrations. The interactive effects of differing pH, mixing proportion, and coagulant dose, were optimised using a statistical tool. Experimental results showed that the best conditions for removing the reactive part of NOM were pH 6, 3.5 mg/L of coagulant, and a mix ratio of 0.76 (mine water:surface water). The results suggested that mixing of this mine water with river water would be an appropriate way to maximise the removal of the reactive part of NOM prior to disinfection and would provide good quality drinking water.

Chromite overburden (COB), considered as a waste material with 46% Fe and 0.8% Ni, is the only source of nickel in India. Iron and nickel from the overburden were recovered through reduction roasting, magnetic separation and smelting. In sintering, maximum Ni% was achieved at 1.0% S, 10% C inside and 10% C outside of the COB pellet. Ni was further enriched by smelting the magnetic fraction of sintered COB. XRD, SEM–EDS and chemical analysis of the feed material and products confirmed enriched Ni content in the ferronickel alloy. With optimised parameters such as time 12 min, basicity 1.2 and 10% reductant, the ferronickel alloy contains 8% Ni and 89% Fe with recovery of 87% Ni. It was possible to produce different grades of ferronickel, varying from 2% to 10% Ni. (Authors.), Chromite overburden (COB), considered as a waste material with 46% Fe and 0.8% Ni, is the only source of nickel in India. Iron and nickel from the overburden were recovered through reduction roasting, magnetic separation and smelting. In sintering, maximum Ni% was achieved at 1.0% S, 10% C inside and 10% C outside of the COB pellet. Ni was further enriched by smelting the magnetic fraction of sintered COB. XRD, SEM–EDS and chemical analysis of the feed material and products confirmed enriched Ni content in the ferronickel alloy. With optimised parameters such as time 12 min, basicity 1.2 and 10% reductant, the ferronickel alloy contains 8% Ni and 89% Fe with recovery of 87% Ni. It was possible to produce different grades of ferronickel, varying from 2% to 10% Ni. (Authors.)

A study has been carried out of the hypochlorite leaching of refractory gold ore using the response surface method-central composite design (RSM-CCD) as a statistical approach in determining the optimum conditions of gold extraction from refractory gold ore. Parameters used were pH 4 to 6, calcium hypochlorite (Ca(OCl)2) concentrations of 0.5 to 1.5 M, and 2.5 to 3.5 M of NaCl in the solution. It was found that the maximum gold extraction of 82.46% (13.85 g/t) was achieved at a pH of 4.0 with NaCl and Ca(OCl)2 concentrations of 2.93 M and 1.08 M, respectively. The statistical analysis also revealed that the amount of gold recovery in chloride solution was significantly dependent on pH as the main factor, followed by concentrations of Ca(OCl)2 and NaCl., A study has been carried out of the hypochlorite leaching of refractory gold ore using the response surface method-central composite design (RSM-CCD) as a statistical approach in determining the optimum conditions of gold extraction from refractory gold ore. Parameters used were pH 4 to 6, calcium hypochlorite (Ca(OCl)2) concentrations of 0.5 to 1.5 M, and 2.5 to 3.5 M of NaCl in the solution. It was found that the maximum gold extraction of 82.46% (13.85 g/t) was achieved at a pH of 4.0 with NaCl and Ca(OCl)2 concentrations of 2.93 M and 1.08 M, respectively. The statistical analysis also revealed that the amount of gold recovery in chloride solution was significantly dependent on pH as the main factor, followed by concentrations of Ca(OCl)2 and NaCl.

A study has been carried out on the use of a dimethyl sulphoxide (DMSO) solution containing copper chloride (CuCl2) in the leaching of chalcopyrite. Experiments were conducted at temperatures from 313 to 413 K and the effects of time and temperature investigated. It was found that copper extraction increased as temperature increased up to 373 K, but then decreased with increasing temperature. When leaching for four hours at 373 K, 94.1% of Cu was extracted along with 46.3% of Fe, 47.8 mmol of S, and 75% of Au. Around 83% of the As remained in the residue. It is concluded that that the DMSO solution could selectively dissolve copper and gold from chalcopyrite while leaving minerals with little economic value, such as pyrite, and the penalty element arsenic in the residues. The extraction of Cu in a given period of time was shown to be faster than that of conventional methods., A study has been carried out on the use of a dimethyl sulphoxide (DMSO) solution containing copper chloride (CuCl2) in the leaching of chalcopyrite. Experiments were conducted at temperatures from 313 to 413 K and the effects of time and temperature investigated. It was found that copper extraction increased as temperature increased up to 373 K, but then decreased with increasing temperature. When leaching for four hours at 373 K, 94.1% of Cu was extracted along with 46.3% of Fe, 47.8 mmol of S, and 75% of Au. Around 83% of the As remained in the residue. It is concluded that that the DMSO solution could selectively dissolve copper and gold from chalcopyrite while leaving minerals with little economic value, such as pyrite, and the penalty element arsenic in the residues. The extraction of Cu in a given period of time was shown to be faster than that of conventional methods.

The quality of the iron ore pellet and the yield of its drying process are directly affected by the drying condition. Such conditions are complex to be predicted or measured due to the heat and mass transfer process of the pellet in chain grate. In this paper, a model is established based on the computational fluid dynamics—discrete element method to describe the heat and mass transfer in updraught drying (UDD) in chain grate. The distribution of temperature field and the change of pellets drying rate in UDD are calculated and analysed. The results indicate that the temperature gradient of pellet bed increases and the water content gradient decreases in movement direction and height direction of pellet bed. The temperature increasing rate and drying rate of the pellet bed show a trend from increasing to decreasing, and this is consistent with previous research. During this period, the temperature of pellet reaches a maximum value of 316 K and the drying rate of pellet reaches a maximum value of 0.42 kg/(m3. s). In addition, the temperature and the drying rate change little in the direction of width of pellet layer, which proves the rationality of simplifying UDD into a two-dimensional model. The proposed model can be used to predict the properties of the pellet drying process and optimise the process parameters., The quality of the iron ore pellet and the yield of its drying process are directly affected by the drying condition. Such conditions are complex to be predicted or measured due to the heat and mass transfer process of the pellet in chain grate. In this paper, a model is established based on the computational fluid dynamics—discrete element method to describe the heat and mass transfer in updraught drying (UDD) in chain grate. The distribution of temperature field and the change of pellets drying rate in UDD are calculated and analysed. The results indicate that the temperature gradient of pellet bed increases and the water content gradient decreases in movement direction and height direction of pellet bed. The temperature increasing rate and drying rate of the pellet bed show a trend from increasing to decreasing, and this is consistent with previous research. During this period, the temperature of pellet reaches a maximum value of 316 K and the drying rate of pellet reaches a maximum value of 0.42 kg/(m3. s). In addition, the temperature and the drying rate change little in the direction of width of pellet layer, which proves the rationality of simplifying UDD into a two-dimensional model. The proposed model can be used to predict the properties of the pellet drying process and optimise the process parameters.

Studies have been carried out of the removal of CO2 from flue gas in a four stage counter current gas-solid fluidised bed reactor using activated carbon (prepared from green coconut shells) with monoethanolamine (MEA) impregnation ratios of 0.2, 0.4, and 0.6. The effects of differing solids flow rate, gas velocity, and weir height on CO2 recovery were ascertained. The best CO2 recovery (94.9%) was achieved for the 0.6 MEA-AC with a solid flow rate of 4.12 kg/h, superficial gas velocity of 0.188 m/s and weir height of 50 mm., Studies have been carried out of the removal of CO2 from flue gas in a four stage counter current gas-solid fluidised bed reactor using activated carbon (prepared from green coconut shells) with monoethanolamine (MEA) impregnation ratios of 0.2, 0.4, and 0.6. The effects of differing solids flow rate, gas velocity, and weir height on CO2 recovery were ascertained. The best CO2 recovery (94.9%) was achieved for the 0.6 MEA-AC with a solid flow rate of 4.12 kg/h, superficial gas velocity of 0.188 m/s and weir height of 50 mm.

The JSW Steel beneficiation plant uses spiral concentrators to process coarse and fine material, but these can't produce the desired product grade in a single stage. Laboratory studies have been carried out to investigate the applicability of a Floatex density separator (FDS) to process the lower grade iron ore fines from the Bellary-Hospet region in Karnataka, India. Two different samples (size fraction between 150 microns and 1 mm, and less than 150 microns) from the JSW Steel beneficiation plant were used. The samples consisted of haematite as the major iron-bearing mineral and goethite as the minor iron-bearing mineral. In both sample it was found that interlocked phases of haematite occurred in varying proportions with gangue minerals such as kaolinite and quartz. Tests were carried out of both samples in a spiral concentrator and in a FDS. The FDS tests were carried out at a constant feed flow rate with varying teeter water flow rates and bed height set point, whereas the feed rate, slurry density and splitter position were varied in the spiral concentrator. The results indicated that the FDS was highly selective in rejecting siliceous and aluminous gangue from the iron ore compared to the spiral concentrator., The JSW Steel beneficiation plant uses spiral concentrators to process coarse and fine material, but these can't produce the desired product grade in a single stage. Laboratory studies have been carried out to investigate the applicability of a Floatex density separator (FDS) to process the lower grade iron ore fines from the Bellary-Hospet region in Karnataka, India. Two different samples (size fraction between 150 microns and 1 mm, and less than 150 microns) from the JSW Steel beneficiation plant were used. The samples consisted of haematite as the major iron-bearing mineral and goethite as the minor iron-bearing mineral. In both sample it was found that interlocked phases of haematite occurred in varying proportions with gangue minerals such as kaolinite and quartz. Tests were carried out of both samples in a spiral concentrator and in a FDS. The FDS tests were carried out at a constant feed flow rate with varying teeter water flow rates and bed height set point, whereas the feed rate, slurry density and splitter position were varied in the spiral concentrator. The results indicated that the FDS was highly selective in rejecting siliceous and aluminous gangue from the iron ore compared to the spiral concentrator.

Studies have been carried out on the processing of castine (CaCO3) for use in Cu-Co hydrometallurgy. The castine was processed into lime using a full-scale rotary kiln and investigations undertaken of the effects of the temperature of the smoke chamber (400, 500, and 550 degrees C), rotational speed of the kiln (120, 90, and 70 s/revolution), and coal flow rate (0.5, 0.7, and 1.0 t/h) on the amount of unburned castine and lime reactivity. Plackett-Burman's experimental plan was used for screening the variables on the calcination yield and the quality of the lime and the Box-Behnken design approach under response surface methodology (RSM) was used to determine the best combination of the variables. Quadratic models were developed to characterise the influence of the variables. The optimal conditions were found to be a smoke chamber temperature of 550 degrees C, rotational speed of 120 s/revolution, and coal flow rate of 0.5 t/h. This gave a minimum unburned castine of 0.93% and lime reactivity of 93.96%. Results predicted by modelling were in fair agreement with the results of the industrial kiln operated under optimal conditions, indicating that the models could be used to estimate castine calcination response., Studies have been carried out on the processing of castine (CaCO3) for use in Cu-Co hydrometallurgy. The castine was processed into lime using a full-scale rotary kiln and investigations undertaken of the effects of the temperature of the smoke chamber (400, 500, and 550 degrees C), rotational speed of the kiln (120, 90, and 70 s/revolution), and coal flow rate (0.5, 0.7, and 1.0 t/h) on the amount of unburned castine and lime reactivity. Plackett-Burman's experimental plan was used for screening the variables on the calcination yield and the quality of the lime and the Box-Behnken design approach under response surface methodology (RSM) was used to determine the best combination of the variables. Quadratic models were developed to characterise the influence of the variables. The optimal conditions were found to be a smoke chamber temperature of 550 degrees C, rotational speed of 120 s/revolution, and coal flow rate of 0.5 t/h. This gave a minimum unburned castine of 0.93% and lime reactivity of 93.96%. Results predicted by modelling were in fair agreement with the results of the industrial kiln operated under optimal conditions, indicating that the models could be used to estimate castine calcination response.

A new hydrometallurgical route was developed for the separation and recovery of Cu from Cu−As-bearing copper electro-refining black slime. The proposed process comprised oxidation acid leaching of Cu−As-bearing slime and selective sulphide precipitation of Cu from the leachate. The effects of various process parameters on the leaching and precipitation of Cu and As were investigated. At the first stage, Cu extraction of 95.2% and As extraction of 97.6% were obtained at 80 degrees C after 4 h with initial H2SO4 concentration of 1.0 mol/l and liquid-to-solid ratio of 10 ml/g. In addition, the leaching kinetics of Cu and As was successfully reproduced by the Avrami model, and the apparent activation energies were found to be 33.6 and 35.1 kJ/mol for the Cu and As leaching reaction, respectively, suggesting a combination of chemical reaction and diffusion control. During the selective sulphide precipitation, about 99.4% Cu was recovered as CuS, while only 0.1% As was precipitated under the optimal conditions using sulphide-to-copper ratio of 2.4:1, time of 1.5 h and temperature of 25 degrees C., A new hydrometallurgical route was developed for the separation and recovery of Cu from Cu−As-bearing copper electro-refining black slime. The proposed process comprised oxidation acid leaching of Cu−As-bearing slime and selective sulphide precipitation of Cu from the leachate. The effects of various process parameters on the leaching and precipitation of Cu and As were investigated. At the first stage, Cu extraction of 95.2% and As extraction of 97.6% were obtained at 80 degrees C after 4 h with initial H2SO4 concentration of 1.0 mol/l and liquid-to-solid ratio of 10 ml/g. In addition, the leaching kinetics of Cu and As was successfully reproduced by the Avrami model, and the apparent activation energies were found to be 33.6 and 35.1 kJ/mol for the Cu and As leaching reaction, respectively, suggesting a combination of chemical reaction and diffusion control. During the selective sulphide precipitation, about 99.4% Cu was recovered as CuS, while only 0.1% As was precipitated under the optimal conditions using sulphide-to-copper ratio of 2.4:1, time of 1.5 h and temperature of 25 degrees C.

Silicon stoichiometry and hydration activity of calcined dolomite are significant determinants of silicothermic magnesium production efficiency. However, current literature focus on discussing effects of these factors on the whole reduction process, and they can not accurately reflect the deeper influence mechanism. The influences of technical parameters on the detailed kinetics were studied experimentally, and kinetic models including process parameters were proposed. Then, these models were combined with the heat transfer model to calculate magnesium reduction and generation rate during the production process by using numerical calculations. Although kinetic experiments show that the magnesium reduction increases with silicon stoichiometry and hydration activity of calcined dolomite, the patterns may differ in industrial production, because the process is also affected by heat transfer. This study can guide manufacturers to adjust technical parameters and reduce the production costs when the prices of raw materials and magnesium fluctuate with the market supply and demand., Silicon stoichiometry and hydration activity of calcined dolomite are significant determinants of silicothermic magnesium production efficiency. However, current literature focus on discussing effects of these factors on the whole reduction process, and they can not accurately reflect the deeper influence mechanism. The influences of technical parameters on the detailed kinetics were studied experimentally, and kinetic models including process parameters were proposed. Then, these models were combined with the heat transfer model to calculate magnesium reduction and generation rate during the production process by using numerical calculations. Although kinetic experiments show that the magnesium reduction increases with silicon stoichiometry and hydration activity of calcined dolomite, the patterns may differ in industrial production, because the process is also affected by heat transfer. This study can guide manufacturers to adjust technical parameters and reduce the production costs when the prices of raw materials and magnesium fluctuate with the market supply and demand.

A chance-constrained goal programming (CCGP) model is presented which is based on the stochastic behaviour of the shovel production. The aims of the model are to simultaneously minimise the total operating costs of the loaded trucks and the deviations from the shovel production, grade requirements at different ore destinations, and ore tonnage received at processing plants. The proposed model has been applied to truck allocation at the Sungun open cast copper mine in Iran using eleven schedule scenarios and different confidence levels for loader production to determine the best allocation of trucks in the mine. Factors considered were total production, number of truck trips, ore grade control, stripping ratio, deviation in production, and operational cost of the trucks. The results show that the model can handle the quality and quantity of material required to achieve the objectives of the short-term production schedule of the mine in all confidence levels, even in the highest risk level. It is concluded that the model has a remarkable ability to meet the required objectives in terms of uncertainty in mining operations., A chance-constrained goal programming (CCGP) model is presented which is based on the stochastic behaviour of the shovel production. The aims of the model are to simultaneously minimise the total operating costs of the loaded trucks and the deviations from the shovel production, grade requirements at different ore destinations, and ore tonnage received at processing plants. The proposed model has been applied to truck allocation at the Sungun open cast copper mine in Iran using eleven schedule scenarios and different confidence levels for loader production to determine the best allocation of trucks in the mine. Factors considered were total production, number of truck trips, ore grade control, stripping ratio, deviation in production, and operational cost of the trucks. The results show that the model can handle the quality and quantity of material required to achieve the objectives of the short-term production schedule of the mine in all confidence levels, even in the highest risk level. It is concluded that the model has a remarkable ability to meet the required objectives in terms of uncertainty in mining operations.

The adsorption characteristics and mechanisms of spirulina powder were investigated when it was used as adsorbent to recover ytterbium(III) from wastewater solution. Surface structure and element valence of the adsorbent were analysed by SEM and XPS for the exploration of its adsorption mechanism for ytterbium(III). The adsorption characteristics of ytterbium(III) on spirulina powder was analysed through assessing adsorption isotherm, kinetics and thermodynamic models. The adsorption isotherm data were best explained by the Langmuir model, and the adsorption capacity of spirulina powder for ytterbium(III) was 72.46 mg/g when the adsorption temperature was 318 K. The kinetic experiment results showed that the pseudo-second order kinetic model can better simulate the adsorption process of spirulina powder to ytterbium(III), indicating that the rate-controlling step was chemical adsorption. Spirulina can be an efficient and economical ytterbium(III) recycling material, because it showed good adsorption stability and reusability from the adsorption−desorption cycle experiment results., The adsorption characteristics and mechanisms of spirulina powder were investigated when it was used as adsorbent to recover ytterbium(III) from wastewater solution. Surface structure and element valence of the adsorbent were analysed by SEM and XPS for the exploration of its adsorption mechanism for ytterbium(III). The adsorption characteristics of ytterbium(III) on spirulina powder was analysed through assessing adsorption isotherm, kinetics and thermodynamic models. The adsorption isotherm data were best explained by the Langmuir model, and the adsorption capacity of spirulina powder for ytterbium(III) was 72.46 mg/g when the adsorption temperature was 318 K. The kinetic experiment results showed that the pseudo-second order kinetic model can better simulate the adsorption process of spirulina powder to ytterbium(III), indicating that the rate-controlling step was chemical adsorption. Spirulina can be an efficient and economical ytterbium(III) recycling material, because it showed good adsorption stability and reusability from the adsorption−desorption cycle experiment results.

Solvent extraction of lanthanum(III) using the organic extractant 2-ethylhexyl phosphonic acid mono-2-ethylhexylester (PC88A) diluted in kerosene from three different aqueous media (sulphuric, nitric and chloride) was investigated. Eh-pH and speciation diagrams suggested that free lanthanum ion (La(III)) species predominate under the experimental conditions studied. The effects of several parameters on the extraction of lanthanum were evaluated, including initial pH (1.5-7), initial La(III) concentration (0.08-1.35 mmol/L), PC88A concentration (10-90 mmol/L) and temperature (25-55 degrees C). In general, both hydrochloric and nitric acids were found to be more effective than sulphuric acid in terms of higher extraction of lanthanum. The stoichiometry of the extraction reaction and also the equilibrium constant were calculated. The extraction of La(III) was significantly enhanced by increasing pH and PC88A concentration and was only slightly increased by increasing temperature. Stripping studies showed that 1 mol/L acid concentration is adequate for effective stripping of lanthanum from the loaded organic. The stoichiometry of the extraction reaction was also investigated using density functional calculations and found to be in reasonable agreement with the experimental results. (Authors.), Solvent extraction of lanthanum(III) using the organic extractant 2-ethylhexyl phosphonic acid mono-2-ethylhexylester (PC88A) diluted in kerosene from three different aqueous media (sulphuric, nitric and chloride) was investigated. Eh-pH and speciation diagrams suggested that free lanthanum ion (La(III)) species predominate under the experimental conditions studied. The effects of several parameters on the extraction of lanthanum were evaluated, including initial pH (1.5-7), initial La(III) concentration (0.08-1.35 mmol/L), PC88A concentration (10-90 mmol/L) and temperature (25-55 degrees C). In general, both hydrochloric and nitric acids were found to be more effective than sulphuric acid in terms of higher extraction of lanthanum. The stoichiometry of the extraction reaction and also the equilibrium constant were calculated. The extraction of La(III) was significantly enhanced by increasing pH and PC88A concentration and was only slightly increased by increasing temperature. Stripping studies showed that 1 mol/L acid concentration is adequate for effective stripping of lanthanum from the loaded organic. The stoichiometry of the extraction reaction was also investigated using density functional calculations and found to be in reasonable agreement with the experimental results. (Authors.)

Laboratory studies have been undertaken to simulate the conditions occurring during the reduction roast step of the Caron Process, with the ultimate aim of identifying the optimum process conditions for Ni extraction. Selected serpentine samples were treated at temperatures between 500 and 800 degrees C in H2/N2 gas mixtures, and leaching tests on the reduced samples were carried out. Phase and microstructural changes were characterised using x-ray powder diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM) techniques. A series of complex physical, microstructure and phase changes were found to occur during reduction roasting involving: the dehydration of serpentine, the formation of a high-silica amorphous phase, the formation of Ni-Fe nanoparticles, and the nucleation, growth and recrystallisation of the forsterite (olivine) phase. The principal mechanism of removal of nickel from the reduced ore was shown to occur through the selective leaching of the Ni-Fe alloy nano-particles from the surfaces in the product oxide., Laboratory studies have been undertaken to simulate the conditions occurring during the reduction roast step of the Caron Process, with the ultimate aim of identifying the optimum process conditions for Ni extraction. Selected serpentine samples were treated at temperatures between 500 and 800 degrees C in H2/N2 gas mixtures, and leaching tests on the reduced samples were carried out. Phase and microstructural changes were characterised using x-ray powder diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM) techniques. A series of complex physical, microstructure and phase changes were found to occur during reduction roasting involving: the dehydration of serpentine, the formation of a high-silica amorphous phase, the formation of Ni-Fe nanoparticles, and the nucleation, growth and recrystallisation of the forsterite (olivine) phase. The principal mechanism of removal of nickel from the reduced ore was shown to occur through the selective leaching of the Ni-Fe alloy nano-particles from the surfaces in the product oxide.

The leaching process and kinetics of copper in high silicon white alloy sulphuric acid oxidation system were studied. Firstly, the effects of additives, sulphuric acid concentration, reaction temperature, reaction time and liquid-solid ratio on the leaching rate of copper and cobalt were systematically studied by single factor experiment. Secondly, the phase and chemical composition of high silicon white alloy and leaching slag were analysed by X-ray diffraction (XRD), inductively coupled plasma (ICP) and scanning electron microscopy (SEM-EDS). The results show that the copper and cobalt leaching rate reach 99.42% and 97.57%, respectively, under the conditions of 5 ml in sodium hypochlorite, 343 K in leaching temperature, 5 h in reaction time, 200 g/l in sulphuric acid concentration and 7:1 in liquid-solid ratio. Finally, by analysing the kinetic model of copper extraction from high silicon white alloy by sulphuric acid oxidation leaching, the activation energy, sulphuric acid concentration and particle size reaction order are 34.64 kJ/mol, 2.34 and 0.18, respectively, indicating that it should follow the chemical reaction control of shrinking core model, and establish the corresponding kinetic equation finally., The leaching process and kinetics of copper in high silicon white alloy sulphuric acid oxidation system were studied. Firstly, the effects of additives, sulphuric acid concentration, reaction temperature, reaction time and liquid-solid ratio on the leaching rate of copper and cobalt were systematically studied by single factor experiment. Secondly, the phase and chemical composition of high silicon white alloy and leaching slag were analysed by X-ray diffraction (XRD), inductively coupled plasma (ICP) and scanning electron microscopy (SEM-EDS). The results show that the copper and cobalt leaching rate reach 99.42% and 97.57%, respectively, under the conditions of 5 ml in sodium hypochlorite, 343 K in leaching temperature, 5 h in reaction time, 200 g/l in sulphuric acid concentration and 7:1 in liquid-solid ratio. Finally, by analysing the kinetic model of copper extraction from high silicon white alloy by sulphuric acid oxidation leaching, the activation energy, sulphuric acid concentration and particle size reaction order are 34.64 kJ/mol, 2.34 and 0.18, respectively, indicating that it should follow the chemical reaction control of shrinking core model, and establish the corresponding kinetic equation finally.

The unascertained theory was applied to establish the evaluation model of slope stability in open-pit mines. According to the cause of influencing the slope stability of open-pit mines, an evaluation system of slope stability of open-pit mines was established, and following 10 factors were selected as the evaluation indicators of unascertained measurement function: slope height(a), final slope angle (b), hydrogeology and engineering geology conditions (c), slope form (d), drainage facility (e), blasting vibration velocity (f), max. scale seismic activity (g), max. daily storm rainfall (h), random mining and site management (i) and, disturbance of slope by personnel and equipment (j). Then, the unascertained measurement functions of a single indicator were constructed, and the entropy method was used to determine the weights of evaluation index. Distance discriminant was adopted as the criterion of attribute recognition. By using the established evaluation model, the stability of the northern slope of a mine was evaluated: (a) 336 m, (b) 27 degrees, (c) 3, (d) 3, (e) 2, (f) 11 cm/s, (g) 8, (h) 43 mm, (i) 2, (j) 2. The results show that the evaluation results are consistent with the actual situation, providing a new method for the mines to evaluate the stability of the open pit mine slope. Besides, the method provides a scientific basis for taking priority measures to improve the stability of slope., The unascertained theory was applied to establish the evaluation model of slope stability in open-pit mines. According to the cause of influencing the slope stability of open-pit mines, an evaluation system of slope stability of open-pit mines was established, and following 10 factors were selected as the evaluation indicators of unascertained measurement function: slope height(a), final slope angle (b), hydrogeology and engineering geology conditions (c), slope form (d), drainage facility (e), blasting vibration velocity (f), max. scale seismic activity (g), max. daily storm rainfall (h), random mining and site management (i) and, disturbance of slope by personnel and equipment (j). Then, the unascertained measurement functions of a single indicator were constructed, and the entropy method was used to determine the weights of evaluation index. Distance discriminant was adopted as the criterion of attribute recognition. By using the established evaluation model, the stability of the northern slope of a mine was evaluated: (a) 336 m, (b) 27 degrees, (c) 3, (d) 3, (e) 2, (f) 11 cm/s, (g) 8, (h) 43 mm, (i) 2, (j) 2. The results show that the evaluation results are consistent with the actual situation, providing a new method for the mines to evaluate the stability of the open pit mine slope. Besides, the method provides a scientific basis for taking priority measures to improve the stability of slope.

Of the four sulphurica acid leaching methods studied - atmospheric, atmospheric with KMnO4, roasting-atmospheric and oxygen pressure - O2 pressure leaching proved most effective for In extraction, 94.1% of In being leached at an optimum 300 g/l H2SO4, 0.4 MPa O2, 10 ml/g liquid-solid ratio and 100 degrees C for 5 h. X-ray diffraction and scanning electron microscopy indicated that Zn, Fe and intermetallic CuZn compounds dissolved to leave PbSO4 and Pb as the major components of the leaching residue. Of the In in solution, 98.5% was selectively extracted with 30% bis(2-ethylhexyl) phosphate and 70% kerosene by 3-stage countercurrent extraction at an organic/aqueous phase ratio of 1/5, 99.5% of In in the organic phase then being stripped by 6 mol/l HCl through 4-stage countercurrent stripping at a 6/1 organic/aqueous phase ratio to give overall In recovery yield of c.92%. The process has the advantages of a short leaching time, high recovery rate and avoidance of harmful gas and solid discharges., Of the four sulphurica acid leaching methods studied - atmospheric, atmospheric with KMnO4, roasting-atmospheric and oxygen pressure - O2 pressure leaching proved most effective for In extraction, 94.1% of In being leached at an optimum 300 g/l H2SO4, 0.4 MPa O2, 10 ml/g liquid-solid ratio and 100 degrees C for 5 h. X-ray diffraction and scanning electron microscopy indicated that Zn, Fe and intermetallic CuZn compounds dissolved to leave PbSO4 and Pb as the major components of the leaching residue. Of the In in solution, 98.5% was selectively extracted with 30% bis(2-ethylhexyl) phosphate and 70% kerosene by 3-stage countercurrent extraction at an organic/aqueous phase ratio of 1/5, 99.5% of In in the organic phase then being stripped by 6 mol/l HCl through 4-stage countercurrent stripping at a 6/1 organic/aqueous phase ratio to give overall In recovery yield of c.92%. The process has the advantages of a short leaching time, high recovery rate and avoidance of harmful gas and solid discharges.

The extraction of manganese from a low-grade manganese oxide ore was investigated in the presence of pretreated straw as reductant in sulphuric acid medium. It was found that concentrated sulphuric acid disrupted the structure of cellulose, hemicellulose and lignin of straw, making it possible to hydrolyse into monosaccharide. The effects of stirring speed, reductant/ore mass ratio, sulphuric acid concentration, ore particle size, leaching temperature and leaching time were examined. The optimal leaching conditions were determined as: stirring speed of 300 rpm, reductant/ore mass ratio of 0.3, sulphuric acid concentration of 9% (v/v), particle size of 45-75 microns and temperature of 85 degrees C for 180 min. Under the above conditions, 92.8% manganese and 10.8% iron were extracted. The experimental results indicated that a high manganese leaching efficiency was achieved with a relatively low iron extraction. (Authors.), The extraction of manganese from a low-grade manganese oxide ore was investigated in the presence of pretreated straw as reductant in sulphuric acid medium. It was found that concentrated sulphuric acid disrupted the structure of cellulose, hemicellulose and lignin of straw, making it possible to hydrolyse into monosaccharide. The effects of stirring speed, reductant/ore mass ratio, sulphuric acid concentration, ore particle size, leaching temperature and leaching time were examined. The optimal leaching conditions were determined as: stirring speed of 300 rpm, reductant/ore mass ratio of 0.3, sulphuric acid concentration of 9% (v/v), particle size of 45-75 microns and temperature of 85 degrees C for 180 min. Under the above conditions, 92.8% manganese and 10.8% iron were extracted. The experimental results indicated that a high manganese leaching efficiency was achieved with a relatively low iron extraction. (Authors.)

Studies have been carried out of the reaction kinetics of hydrogen reduction of iron ore concentrates from the Gol-E-Gohar mine in Iran. Thermogravimetric analysis was used to study the reaction progress at a temperature range of 700-900 degrees C. Various methods were used to obtain the governing mechanism and reaction rate constant. Taking into account the effects of impurities, the reduction rate of ore concentrate was found to be between the reduction rates of pure magnetite and pure wustite. The experimental work showed that hydrogen reduction of magnetite to wustite has the greatest chance of occurrence at temperature range over 700 degrees C. The reduction reaction can occur as a single-step reaction above 1000 degrees C. The first-order reaction was a very important model for this reduction at the studied temperature range. The activation energy obtained was around 29.48 kJ/mol., Studies have been carried out of the reaction kinetics of hydrogen reduction of iron ore concentrates from the Gol-E-Gohar mine in Iran. Thermogravimetric analysis was used to study the reaction progress at a temperature range of 700-900 degrees C. Various methods were used to obtain the governing mechanism and reaction rate constant. Taking into account the effects of impurities, the reduction rate of ore concentrate was found to be between the reduction rates of pure magnetite and pure wustite. The experimental work showed that hydrogen reduction of magnetite to wustite has the greatest chance of occurrence at temperature range over 700 degrees C. The reduction reaction can occur as a single-step reaction above 1000 degrees C. The first-order reaction was a very important model for this reduction at the studied temperature range. The activation energy obtained was around 29.48 kJ/mol.

The leaching and kinetics of malachite in alkaline glycine solutions have been studied and the influence of process variables such as glycine concentration, temperature, particle size and stirring speed on leaching kinetics evaluated. The results show that temperature has the most significant effect on leaching rate with 100% copper dissolution in just less that 30 minutes at 50 degrees C, while at 25 degrees C complete copper dissolution was only obtained after 3 hours. Increasing glycine concentration and reducing particle size led to an increase in copper extraction rates; no significant influence was observed with stirring speeds above 350 rpm. Kinetic analysis using the shrinking core model indicated that the initial leaching rate of malachite in alkaline glycine solution is controlled by diffusion through the product layer. The apparent activation energy was found to be 48.3 kJ/mol. It is concluded that although alkaline glycine leach rates are slower than acid leaching with sulphuric acid, the rates are practical for all leach modes and alleviate the downstream problems. The inherent recyclability after copper recovery considerably lowers reagent costs., The leaching and kinetics of malachite in alkaline glycine solutions have been studied and the influence of process variables such as glycine concentration, temperature, particle size and stirring speed on leaching kinetics evaluated. The results show that temperature has the most significant effect on leaching rate with 100% copper dissolution in just less that 30 minutes at 50 degrees C, while at 25 degrees C complete copper dissolution was only obtained after 3 hours. Increasing glycine concentration and reducing particle size led to an increase in copper extraction rates; no significant influence was observed with stirring speeds above 350 rpm. Kinetic analysis using the shrinking core model indicated that the initial leaching rate of malachite in alkaline glycine solution is controlled by diffusion through the product layer. The apparent activation energy was found to be 48.3 kJ/mol. It is concluded that although alkaline glycine leach rates are slower than acid leaching with sulphuric acid, the rates are practical for all leach modes and alleviate the downstream problems. The inherent recyclability after copper recovery considerably lowers reagent costs.

Optimising size distribution of ball mill product can be carried out by minimising the product 80% passing size or by minimising the amount of -37 micron fraction to prevent overgrinding. A functional relationship has been developed between three grinding variables (ball size, grinding time and solid content) and the grinding responses (d80 of product and amount of -37 micron fraction). Grinding experiments were conducted using a laboratory ball mill with copper sulphide ore. A three-level Box-Bhenken design combining a response surface methodology with a quadratic model was used to determine significant factors that affect grinding, and to develop a model for process optimisation. Results showed that the modelled values for d80 and amount of -37 micron fraction in the product were in good agreement with experimental values. It is concluded that Box-Bhenken design can be used efficiently for the optimisation of grinding parameters to improve size distribution of ball mill product., Optimising size distribution of ball mill product can be carried out by minimising the product 80% passing size or by minimising the amount of -37 micron fraction to prevent overgrinding. A functional relationship has been developed between three grinding variables (ball size, grinding time and solid content) and the grinding responses (d80 of product and amount of -37 micron fraction). Grinding experiments were conducted using a laboratory ball mill with copper sulphide ore. A three-level Box-Bhenken design combining a response surface methodology with a quadratic model was used to determine significant factors that affect grinding, and to develop a model for process optimisation. Results showed that the modelled values for d80 and amount of -37 micron fraction in the product were in good agreement with experimental values. It is concluded that Box-Bhenken design can be used efficiently for the optimisation of grinding parameters to improve size distribution of ball mill product.

Factorial design has been used to develop regression equations for leaching of Y and Eu from the phosphor coating of spent fluorescent lamps. H2SO4 was found to be the most suitable lixiviant. The parameters used for factorial design were temperature, H2SO4 concentration and pulp density. Leaching extent obtained at design conditions were fed to Minitab and regression equations for 1, 2, 3 and 4 hours were generated. Experimental results were within ±5% w/w of calculated values. The equations were solved for 99.9-100% leaching and the results represented as response surfaces. More than 99% of Y and Eu was leached with H2SO4 of concentration 6-9.3% v/v at temperature 70-95 degrees C and pulp density 5-20% w/v in 3 hours. Leaching extents required for kinetic studies were also determined from regression equations., Factorial design has been used to develop regression equations for leaching of Y and Eu from the phosphor coating of spent fluorescent lamps. H2SO4 was found to be the most suitable lixiviant. The parameters used for factorial design were temperature, H2SO4 concentration and pulp density. Leaching extent obtained at design conditions were fed to Minitab and regression equations for 1, 2, 3 and 4 hours were generated. Experimental results were within ±5% w/w of calculated values. The equations were solved for 99.9-100% leaching and the results represented as response surfaces. More than 99% of Y and Eu was leached with H2SO4 of concentration 6-9.3% v/v at temperature 70-95 degrees C and pulp density 5-20% w/v in 3 hours. Leaching extents required for kinetic studies were also determined from regression equations.

This paper aims to experimentally investigate the different parameters affecting the production of electrolytic copper powder from copper cables scrap anode particles using a static-bed electrolysis technique. This technique depends mainly on cutting the longest cables manually and putting them in a metal basket made from titanium. Two cathodes made of stainless steel sheets with the anode basket were submerged in an acidic solution containing H2SO4 and copper sulphate with an organic agent. The effect of different parameters on the electrolysis process such as electrolyte temperature, stirring rate, current density, copper ions in the electrolyte, sulphuric acid, adding polyvinylpyrrolidone (PVP) and the use of an old electrolyte were studied and evaluated. Electrolytic copper powder was obtained in dentritic and dispersed shapes with purity up to 99.938% Cu and apparent density from 1.544 to 4.080 g/cm3. The electrolysis process was accomplished with cathodic current efficiency to 100%, specific energy demand between 1.184 and 2.960 kWh/kg Cu and powder productivity of 1.188g/Ah., This paper aims to experimentally investigate the different parameters affecting the production of electrolytic copper powder from copper cables scrap anode particles using a static-bed electrolysis technique. This technique depends mainly on cutting the longest cables manually and putting them in a metal basket made from titanium. Two cathodes made of stainless steel sheets with the anode basket were submerged in an acidic solution containing H2SO4 and copper sulphate with an organic agent. The effect of different parameters on the electrolysis process such as electrolyte temperature, stirring rate, current density, copper ions in the electrolyte, sulphuric acid, adding polyvinylpyrrolidone (PVP) and the use of an old electrolyte were studied and evaluated. Electrolytic copper powder was obtained in dentritic and dispersed shapes with purity up to 99.938% Cu and apparent density from 1.544 to 4.080 g/cm3. The electrolysis process was accomplished with cathodic current efficiency to 100%, specific energy demand between 1.184 and 2.960 kWh/kg Cu and powder productivity of 1.188g/Ah.

A model has been produced for block cave mining production scheduling for short-term mine planning under a range of uncertainties. The model considered tonnage and grade as daily production targets and operational constraints including drawpoints and ore pass design, draw rate, mine production, and transportation capacities in different operational levels. The model can handle decision variables for both production and transportation levels that have non-linear relationships. A real-case copper block cave mining dataset was used to check the performance of the model under the uncertainty of demand and operational failures for three different scenarios: the base case, target grade, and drawpoint failure. The dataset consisted of two sectors, one with 250 drawpoints and 81 ore passes and the other with 234 drawpoints and 43 orepasses with the limited available tonnage for a period of 17 days. The results showed that the proposed model could minimise deviations from operational targets, allowing targets to be achieved., A model has been produced for block cave mining production scheduling for short-term mine planning under a range of uncertainties. The model considered tonnage and grade as daily production targets and operational constraints including drawpoints and ore pass design, draw rate, mine production, and transportation capacities in different operational levels. The model can handle decision variables for both production and transportation levels that have non-linear relationships. A real-case copper block cave mining dataset was used to check the performance of the model under the uncertainty of demand and operational failures for three different scenarios: the base case, target grade, and drawpoint failure. The dataset consisted of two sectors, one with 250 drawpoints and 81 ore passes and the other with 234 drawpoints and 43 orepasses with the limited available tonnage for a period of 17 days. The results showed that the proposed model could minimise deviations from operational targets, allowing targets to be achieved.

Studies have been carried out of the relationship between the oxidation behaviour of low FeO Indian chromite ore and process conditions (oxidation temperature and holding time) using a combination of experimental and simulation techniques. Non-isothermal differential scanning calorimetry and thermogravimetric (TG) analysis were conducted at temperatures of 100 to 1100 degrees C to deduce the phase transformations during the oxidation process. Isothermal TG analyses were conducted at 700, 800 and 1000 degrees C with holding time varying between 0 and 180 min. The effect of temperature and time on the phase transformation of chromite spinel to sesquioxide phase was evaluated and thermodynamic calculations were carried out to study the distribution of different elements in chromite and sesquioxide phases during the oxidation process. Kinetic analysis was conducted to investigate the rate controlling phenomena. The results show that phase transformation kinetics are accelerated with increasing temperature and time, and 60-120 minutes oxidation treatment at 1000 degrees C is sufficient to attain equilibrium conditions. The kinetic analysis results in conjunction with experimental oxidation data indicate that phase transformation is both chemical reaction and diffusion controlled., Studies have been carried out of the relationship between the oxidation behaviour of low FeO Indian chromite ore and process conditions (oxidation temperature and holding time) using a combination of experimental and simulation techniques. Non-isothermal differential scanning calorimetry and thermogravimetric (TG) analysis were conducted at temperatures of 100 to 1100 degrees C to deduce the phase transformations during the oxidation process. Isothermal TG analyses were conducted at 700, 800 and 1000 degrees C with holding time varying between 0 and 180 min. The effect of temperature and time on the phase transformation of chromite spinel to sesquioxide phase was evaluated and thermodynamic calculations were carried out to study the distribution of different elements in chromite and sesquioxide phases during the oxidation process. Kinetic analysis was conducted to investigate the rate controlling phenomena. The results show that phase transformation kinetics are accelerated with increasing temperature and time, and 60-120 minutes oxidation treatment at 1000 degrees C is sufficient to attain equilibrium conditions. The kinetic analysis results in conjunction with experimental oxidation data indicate that phase transformation is both chemical reaction and diffusion controlled.

The efficiency of the smelting reduction process mainly depends on the energy input (smelting power), reducing agent (carbon rate) and slag composition (basicity and viscosity). Laboratory tests were carried out using different blends of low-grade Mn/Fe ores and smelting powers of 20-30 kWh, carbon rate from 10 to 20% of ore, and slag basicity from 0.1 to 0.3. It was found that the basicity and fluidity of the slag played an important role in slag metal separation and had an impact on the composition of the metal produced. The optimum Mn and Fe separation (over 85%) was achieved by smelting a 10 kg Mn ore batch in a 50 kVA electric arc furnace using 30 kWh of smelting power and 0.16 kg of coke. Slag basicity was maintained at 0.3, and the optimum slag SiO2 was about 30%. Different grade high-MnO slags and manganese pigs could be produced using these process conditions. The high-MnO slag can be used as synthetic ore for ferroalloy production, and can obtain prices of around US, The efficiency of the smelting reduction process mainly depends on the energy input (smelting power), reducing agent (carbon rate) and slag composition (basicity and viscosity). Laboratory tests were carried out using different blends of low-grade Mn/Fe ores and smelting powers of 20-30 kWh, carbon rate from 10 to 20% of ore, and slag basicity from 0.1 to 0.3. It was found that the basicity and fluidity of the slag played an important role in slag metal separation and had an impact on the composition of the metal produced. The optimum Mn and Fe separation (over 85%) was achieved by smelting a 10 kg Mn ore batch in a 50 kVA electric arc furnace using 30 kWh of smelting power and 0.16 kg of coke. Slag basicity was maintained at 0.3, and the optimum slag SiO2 was about 30%. Different grade high-MnO slags and manganese pigs could be produced using these process conditions. The high-MnO slag can be used as synthetic ore for ferroalloy production, and can obtain prices of around US

A 1:16 scale LHD model has been used to study the effects of bucket orientation and operating parameters on resistive forces and penetration for rubber-tyre loaders (RTLs) such as load-haul-dumps and front-end loaders. A full factorial design experiment was carried out to test an RTL bucket operating at different levels of traction (tractive effort), speed, digging height and rake angles. The test was repeated on two muck piles with different particle sizes, and generalised regression modelling was applied. The results show that speed and tractive effort are more important in explaining RTL penetration and resistive forces than height above the floor and rake angle. Speed, tractive effort and height above the floor are positively correlated to bucket penetration, whereas the rake angle is negatively correlated to penetration. Similarly, speed, tractive effort, rake angle and height above the floor are all positively correlated to resistive forces incurred during initial penetration. The results show that the combined effect of speed and tractive effort is negatively correlated to penetration and resistive forces, and that the effects of speed, tractive effort and height above the floor all change with changes in particle sizes., A 1:16 scale LHD model has been used to study the effects of bucket orientation and operating parameters on resistive forces and penetration for rubber-tyre loaders (RTLs) such as load-haul-dumps and front-end loaders. A full factorial design experiment was carried out to test an RTL bucket operating at different levels of traction (tractive effort), speed, digging height and rake angles. The test was repeated on two muck piles with different particle sizes, and generalised regression modelling was applied. The results show that speed and tractive effort are more important in explaining RTL penetration and resistive forces than height above the floor and rake angle. Speed, tractive effort and height above the floor are positively correlated to bucket penetration, whereas the rake angle is negatively correlated to penetration. Similarly, speed, tractive effort, rake angle and height above the floor are all positively correlated to resistive forces incurred during initial penetration. The results show that the combined effect of speed and tractive effort is negatively correlated to penetration and resistive forces, and that the effects of speed, tractive effort and height above the floor all change with changes in particle sizes.

The ratio of Zn extraction from hemimorphite (calamine) to water-soluble Zn sulphate has been studied at various leaching times and temperatures using ore from the Shaimerden deposits in Kazakhstan. Sulphuric acid leaching was carried out at temperatures of 20, 40, 60, and 80 degrees C for 5, 10, 15, and 20 minutes. The results showed that Zn extraction increased with increasing temperature and time, with almost 65% Zn extraction achieved in 20 minutes at a temperature of 80 degrees C. The calculated value of the apparent activation energy suggests that the studied process takes place in the diffusion region. It can be be assumed that this process is limited by the rate of diffusion of acid molecules to the reaction surface through a layer of the resulting reaction products (poorly soluble hydrated silica and soluble zinc sulphate). It is concluded that the process studied, used in a countercurrent flow, would be suitable for industrial processing of the ore instead of the expensive Waelz process currently used., The ratio of Zn extraction from hemimorphite (calamine) to water-soluble Zn sulphate has been studied at various leaching times and temperatures using ore from the Shaimerden deposits in Kazakhstan. Sulphuric acid leaching was carried out at temperatures of 20, 40, 60, and 80 degrees C for 5, 10, 15, and 20 minutes. The results showed that Zn extraction increased with increasing temperature and time, with almost 65% Zn extraction achieved in 20 minutes at a temperature of 80 degrees C. The calculated value of the apparent activation energy suggests that the studied process takes place in the diffusion region. It can be be assumed that this process is limited by the rate of diffusion of acid molecules to the reaction surface through a layer of the resulting reaction products (poorly soluble hydrated silica and soluble zinc sulphate). It is concluded that the process studied, used in a countercurrent flow, would be suitable for industrial processing of the ore instead of the expensive Waelz process currently used.

This chapter provides a systematic discussion of the origins, development and influence of structural realism in Europe. It identifies the characteristics of European structural realism and discusses how European structural realist thought has spilled back into the discipline of international relations. European realists have influenced the realist perspective on international relations and realist debates on international relations from three points departure, which also coincide with three overlapping waves of theorizing: 1) Pre-structural realism associated with classical English School realists such as Martin Wight, Hedley Bull and Herbert Butterfield; 2) Structural realism exploring how systemic processes transmit and modify structural incentives, while pointing to the continued importance of power politics; 3) Post-structural realism associated with the Copenhagen School pushing realist thinking beyond state-centric actorness and exploring the link between political discourse and material power.

Sintering of iron ore is a complex coupling process involving multiple physical factors and a complex thermal state of pellets during travelling-grate processes. Computational fluid dynamics (CFD) and four-factor three-level orthogonal testing are used to investigate the temperature distribution during the updraught drying stage, where hot gas is transported by convection up through the bed of green ore pellets, from calculated temperature profiles and temperature increase at different positions. The results indicate that the temperature of the inlet gas has the greatest influence on the pellet bed, followed by bed height. The proposed computational framework could also be used to evaluate and design the thermodynamic parameters of travelling-grate processes., Sintering of iron ore is a complex coupling process involving multiple physical factors and a complex thermal state of pellets during travelling-grate processes. Computational fluid dynamics (CFD) and four-factor three-level orthogonal testing are used to investigate the temperature distribution during the updraught drying stage, where hot gas is transported by convection up through the bed of green ore pellets, from calculated temperature profiles and temperature increase at different positions. The results indicate that the temperature of the inlet gas has the greatest influence on the pellet bed, followed by bed height. The proposed computational framework could also be used to evaluate and design the thermodynamic parameters of travelling-grate processes.

An Outotec thickener optimiser has been used at the Yara Siilinjarvi paste plant in Finland since 2017. The mine produces around 1 000 000 t/year of apatite concentrate for fertiliser production, and 10 000 000 t/year of tailings. Control of the plant has to take account of varying mineralogy, milling from different stockpiles, and location and manning of the plant. The thickener control application uses the Model Predictive Control algorithm, which is based on processes response models obtained by performing process trials or by simulation. The controlled variables in the system are underflow density, overflow solids content, bed mass, bed level, and rake torque. The system has been integrated with the current distributed control system at the plant, and can be used from the same interface. The thickener has delivered a consistent performance since start-up, with an overall plant availability of over 97%. Underflow solids have been kept continuously at the required level of 66-60% and the achieved average beach slope angles are over 3.5 degrees. There has also been a 10-20% reduction in flocculant consumption, which has given large savings in plant operating costs., An Outotec thickener optimiser has been used at the Yara Siilinjarvi paste plant in Finland since 2017. The mine produces around 1 000 000 t/year of apatite concentrate for fertiliser production, and 10 000 000 t/year of tailings. Control of the plant has to take account of varying mineralogy, milling from different stockpiles, and location and manning of the plant. The thickener control application uses the Model Predictive Control algorithm, which is based on processes response models obtained by performing process trials or by simulation. The controlled variables in the system are underflow density, overflow solids content, bed mass, bed level, and rake torque. The system has been integrated with the current distributed control system at the plant, and can be used from the same interface. The thickener has delivered a consistent performance since start-up, with an overall plant availability of over 97%. Underflow solids have been kept continuously at the required level of 66-60% and the achieved average beach slope angles are over 3.5 degrees. There has also been a 10-20% reduction in flocculant consumption, which has given large savings in plant operating costs.

For the ironmaking process, a decreased Si content in pig iron is beneficial for increasing the coefficient of utilisation of the capacity of blast furnace, reducing the fuel consumption and increasing the output; for the following steelmaking process, a decrease in Si is beneficial for reducing the amount of slag and consumption of flux and for shortening the steelmaking time, making Si decrease an important technology for overall productivity enhancement and energy saving. The transfer mechanism and influence factors of Si in a blast furnace are reviewed and discussed in detail from the thermodynamic and kinetic viewpoints and a theoretical basis and operational strategies provided for reducing the Si content. The main aspects to be addressed are decreasing the amount of Si in the raw materials for charging, suppressing SiO2 reduction and SiO gas absorption, and promoting desiliconisation reactions in the slag-metal interface. In addition, advanced online monitoring and prediction models are needed to detect Si contents of the charge and melt and to adjust blast-furnace parameters accordingly., For the ironmaking process, a decreased Si content in pig iron is beneficial for increasing the coefficient of utilisation of the capacity of blast furnace, reducing the fuel consumption and increasing the output; for the following steelmaking process, a decrease in Si is beneficial for reducing the amount of slag and consumption of flux and for shortening the steelmaking time, making Si decrease an important technology for overall productivity enhancement and energy saving. The transfer mechanism and influence factors of Si in a blast furnace are reviewed and discussed in detail from the thermodynamic and kinetic viewpoints and a theoretical basis and operational strategies provided for reducing the Si content. The main aspects to be addressed are decreasing the amount of Si in the raw materials for charging, suppressing SiO2 reduction and SiO gas absorption, and promoting desiliconisation reactions in the slag-metal interface. In addition, advanced online monitoring and prediction models are needed to detect Si contents of the charge and melt and to adjust blast-furnace parameters accordingly.

A coupled flow and refractory model (CFRM) has been upgraded to assist engineers in understanding and interpreting the measured refractory temperature distributions in the hearth of a blast furnace. The model describes the liquid flow distribution and heat transfer in the hearth, allowing various scenarios to be simulated involving variables such as coke bed properties and extent of hearth refractory wear. The model was validated through comparison between measured refractory data and corresponding model predictions for the early stages of BlueScope’s current No.5 blast furnace campaign. For this campaign, the actual range in measured pad temperature fluctuation over a short time period is shown to be well within the temperature difference expected for typical coke bed movement between sitting and floating bed conditions. Over a longer time span, a consistent evolution of the refractory wear is suggested and this is imposed to elucidate the increase in overall hearth pad temperature. (Authors.), A coupled flow and refractory model (CFRM) has been upgraded to assist engineers in understanding and interpreting the measured refractory temperature distributions in the hearth of a blast furnace. The model describes the liquid flow distribution and heat transfer in the hearth, allowing various scenarios to be simulated involving variables such as coke bed properties and extent of hearth refractory wear. The model was validated through comparison between measured refractory data and corresponding model predictions for the early stages of BlueScope’s current No.5 blast furnace campaign. For this campaign, the actual range in measured pad temperature fluctuation over a short time period is shown to be well within the temperature difference expected for typical coke bed movement between sitting and floating bed conditions. Over a longer time span, a consistent evolution of the refractory wear is suggested and this is imposed to elucidate the increase in overall hearth pad temperature. (Authors.)

A system dynamic model (SDM) is proposed which models drilling and blasting operations over time as an interactive system. Factors which are taken into account include technical parameters (including burden, spacing, depth, bit or drill hole diameter, penetration rate), economic parameters (bit cost, hourly drilling costs, drilling and blasting operational costs), and environmental parameters such as gas emissions. The model is used to find the optimum bit diameter in the case of a hypothetical open pit copper mine which needs to produce 25 million tonnes of ore and 30 million tonnes of waste working 340 days a year. An optimisation process for bit diameter under both deterministic and uncertain conditions was carried out. It was shown that the optimum result can be totally different in the case of deterministic (8.33 inches diameter) and uncertainty (ranging between 7.997 and 8.285 inches). The total drilling and blasting costs under uncertainty conditions varied between US, A system dynamic model (SDM) is proposed which models drilling and blasting operations over time as an interactive system. Factors which are taken into account include technical parameters (including burden, spacing, depth, bit or drill hole diameter, penetration rate), economic parameters (bit cost, hourly drilling costs, drilling and blasting operational costs), and environmental parameters such as gas emissions. The model is used to find the optimum bit diameter in the case of a hypothetical open pit copper mine which needs to produce 25 million tonnes of ore and 30 million tonnes of waste working 340 days a year. An optimisation process for bit diameter under both deterministic and uncertain conditions was carried out. It was shown that the optimum result can be totally different in the case of deterministic (8.33 inches diameter) and uncertainty (ranging between 7.997 and 8.285 inches). The total drilling and blasting costs under uncertainty conditions varied between US

This paper presents results of the analysis of selected indicators used to assess the efficiency of a blast furnace operation: running time operation, plan fulfilment, unit daily production of pig iron and the influence of these parameters on monthly pig iron production and intensity of coke combustion. High values (over 95%) were obtained for running time utilisation and plan fulfilment. The value of unit daily production was at an average level, ca. 1.6 Mg/24h/m3, which is slightly lower than the optimal value for similar devices. The study was carried out in cooperation with a Blast-Furnace Department of a Polish steelworks and was based on the results coming from this Department. The analysis covers the period of one calendar year., This paper presents results of the analysis of selected indicators used to assess the efficiency of a blast furnace operation: running time operation, plan fulfilment, unit daily production of pig iron and the influence of these parameters on monthly pig iron production and intensity of coke combustion. High values (over 95%) were obtained for running time utilisation and plan fulfilment. The value of unit daily production was at an average level, ca. 1.6 Mg/24h/m3, which is slightly lower than the optimal value for similar devices. The study was carried out in cooperation with a Blast-Furnace Department of a Polish steelworks and was based on the results coming from this Department. The analysis covers the period of one calendar year.

The paper reviews the current literature on extraction column simulation when using droplet population modelling. Numerical methods are briefly discussed and background information to necessary kernels and correlations as well as parameter evaluation is presented. This comprises physical and chemically enhanced mass transfer, droplet movement and interactions in stirred columns. Furthermore, the benefits of CFD calculations to resolve local hydrodynamic details or ultra-fast simulation concepts for model-based forward control are covered. The hydrodynamics and mass transfer in liquid-liquid extraction columns (LLECs) involve a larger number of operating variables than vapour-liquid unit operations, which makes the scale-up of LLEC difficult and hence pilot-scale experiments are still inevitable. Bench-scale semi-continuous experiments give a firm basis to evaluate the droplet interactions. The droplet breakage can be easily correlated via power input or energy dissipation but the coalescence behaviour is more difficult to describe. An alternative is to obtain the coalescence parameters numerically in an optimisation procedure, as is to solve the so-called inverse population balance problem. In this paper, correlations are reviewed for a population balance model (PBM)-based LLEC simulation. Finally, two case studies for an RDC and Kühni extraction column provide in detail the methodology on how to handle a design case which in principle can be extended to other extraction apparatus., The paper reviews the current literature on extraction column simulation when using droplet population modelling. Numerical methods are briefly discussed and background information to necessary kernels and correlations as well as parameter evaluation is presented. This comprises physical and chemically enhanced mass transfer, droplet movement and interactions in stirred columns. Furthermore, the benefits of CFD calculations to resolve local hydrodynamic details or ultra-fast simulation concepts for model-based forward control are covered. The hydrodynamics and mass transfer in liquid-liquid extraction columns (LLECs) involve a larger number of operating variables than vapour-liquid unit operations, which makes the scale-up of LLEC difficult and hence pilot-scale experiments are still inevitable. Bench-scale semi-continuous experiments give a firm basis to evaluate the droplet interactions. The droplet breakage can be easily correlated via power input or energy dissipation but the coalescence behaviour is more difficult to describe. An alternative is to obtain the coalescence parameters numerically in an optimisation procedure, as is to solve the so-called inverse population balance problem. In this paper, correlations are reviewed for a population balance model (PBM)-based LLEC simulation. Finally, two case studies for an RDC and Kühni extraction column provide in detail the methodology on how to handle a design case which in principle can be extended to other extraction apparatus.

Ghana Manganese Company (GMC) have renovated their oxide washing plant at the Nsuta mine by integrating it with a spiral classifier to make a batch system operating process. Particle sizes below 3.35mm (Mn grade 43-47%) from the primary section of the plant are used as feed to the classifier. Various operational parameters of the classifier were used to obtain a Mn grade greater than 50% using Design of Experiment (DOE). The variables were washing time (30-90 min), speed of spirals (20-40 rev/min) and feed tonnage (6-9 t). The outcome of the test work after simulation showed that all the selected parameters had a great influence on Mn grade. The spiral speed and feed tonnage correlated negatively to the Mn grade with washing time correlating positively. Operating the spiral classifier at a feed rate of 6 t, spiral speed of 25 rev/min, and 30 minutes washing time yielded Mn grade of 53%, which is a 4% increment on the previous grade. The new parameters have been put into operation at the plant, producing a manganese concentrate grade ranging between 52-54%., Ghana Manganese Company (GMC) have renovated their oxide washing plant at the Nsuta mine by integrating it with a spiral classifier to make a batch system operating process. Particle sizes below 3.35mm (Mn grade 43-47%) from the primary section of the plant are used as feed to the classifier. Various operational parameters of the classifier were used to obtain a Mn grade greater than 50% using Design of Experiment (DOE). The variables were washing time (30-90 min), speed of spirals (20-40 rev/min) and feed tonnage (6-9 t). The outcome of the test work after simulation showed that all the selected parameters had a great influence on Mn grade. The spiral speed and feed tonnage correlated negatively to the Mn grade with washing time correlating positively. Operating the spiral classifier at a feed rate of 6 t, spiral speed of 25 rev/min, and 30 minutes washing time yielded Mn grade of 53%, which is a 4% increment on the previous grade. The new parameters have been put into operation at the plant, producing a manganese concentrate grade ranging between 52-54%.

Studies have been carried out to assess the ability of Phanerochaete chrysosporium to degrade cyanide in gold and silver effluents under different conditions, including changes in cyanide concentration, culture mass, time, closed system and open system. Analytical grade sodium cyanide, sodium hydroxide, and silver nitrate were used along with fungal spores of Phanerochaete chrysosporium grown on a millet and corn cob medium. At the end of 24 hour contact in an open agitated system with initial pH of 11.5, a control experiment using 100 mg/L cyanide revealed a natural attenuation of 15% with pH decreasing to 9.88, while the best myco-detoxification of 85% was achieved by contacting 100 mg/L cyanide with 0.5 g culture mass, translating into degradation capacity of 17.2 mg/g (milligram of cyanide per gram of culture) with pH reducing to 8.4 in 24 hours. The degradation could be based on a number of mechanisms including hydrolysis to HCN, oxidation to cyanyl radical and cyanate due to natural attenuation through atmospheric contact, and secretion of organic acid, oxidative enzymes, and hydrogen peroxide by the fungus., Studies have been carried out to assess the ability of Phanerochaete chrysosporium to degrade cyanide in gold and silver effluents under different conditions, including changes in cyanide concentration, culture mass, time, closed system and open system. Analytical grade sodium cyanide, sodium hydroxide, and silver nitrate were used along with fungal spores of Phanerochaete chrysosporium grown on a millet and corn cob medium. At the end of 24 hour contact in an open agitated system with initial pH of 11.5, a control experiment using 100 mg/L cyanide revealed a natural attenuation of 15% with pH decreasing to 9.88, while the best myco-detoxification of 85% was achieved by contacting 100 mg/L cyanide with 0.5 g culture mass, translating into degradation capacity of 17.2 mg/g (milligram of cyanide per gram of culture) with pH reducing to 8.4 in 24 hours. The degradation could be based on a number of mechanisms including hydrolysis to HCN, oxidation to cyanyl radical and cyanate due to natural attenuation through atmospheric contact, and secretion of organic acid, oxidative enzymes, and hydrogen peroxide by the fungus.

Studies have been carried out on the effects of drying temperatures on the pore structure and oxygen-containing functional groups of lignite. The moisture form, functional groups, effective water-filled pores and equilibrium moisture content of the lignite before and after the drying process were investigated using differential scanning calorimetry, Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy and a self-made reabsorption device. The results show that low drying temperature (140, 190, 230 degrees C for 10 minutes) had little impact on the effective water-filled porosities, whereas it had a great influence on the main oxygen-containing functional groups, which firstly decreased and then increased with the drying temperature. At higher temperatures (600, 700, 800 degrees C for 30 seconds), the effective water-filled porosity of the sample decreased and the amount of oxygen-containing functional groups increased with temperature. The reabsorption capability of the high temperature dried sample was much lower than for the low temperature dried samples. The reabsorption characteristics of the latter were affected by the amount of the oxygen-containing functional groups, while the effective water-filled porosity was the main factor for samples derived from high temperature drying. It is concluded that the high-temperature drying process is an effective choice for lignite upgrading., Studies have been carried out on the effects of drying temperatures on the pore structure and oxygen-containing functional groups of lignite. The moisture form, functional groups, effective water-filled pores and equilibrium moisture content of the lignite before and after the drying process were investigated using differential scanning calorimetry, Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy and a self-made reabsorption device. The results show that low drying temperature (140, 190, 230 degrees C for 10 minutes) had little impact on the effective water-filled porosities, whereas it had a great influence on the main oxygen-containing functional groups, which firstly decreased and then increased with the drying temperature. At higher temperatures (600, 700, 800 degrees C for 30 seconds), the effective water-filled porosity of the sample decreased and the amount of oxygen-containing functional groups increased with temperature. The reabsorption capability of the high temperature dried sample was much lower than for the low temperature dried samples. The reabsorption characteristics of the latter were affected by the amount of the oxygen-containing functional groups, while the effective water-filled porosity was the main factor for samples derived from high temperature drying. It is concluded that the high-temperature drying process is an effective choice for lignite upgrading.

A bench-scale indirect pulsation-assisted fluidised bed dryer with a 0.24 m2 cross-section has been built to study the drying of lignite. The fluidised bed dryer with tube bundles was used to investigate the scale-up effect on the drying rate of the pulsed flow using superheated steam as the drying medium. Particle agglomeration was found to be a serious problem when increasing the size of the dryer. Agglomeration could be reduced by enhancing the drying rate by increasing the horizontal diffusion rate with the pulsation-assisted flow. It was found that pulsation-assisted flow enhanced the drying rate by nearly 40% compared to that of the steady flow at a gas velocity of 0.29 m/s, and 20% at a gas velocity of 0.19 m/s. The frequency of pulsed flow also affected the drying rate, with 3 and 5 Hz pulsed flow having a higher drying rate than that of 1 Hz., A bench-scale indirect pulsation-assisted fluidised bed dryer with a 0.24 m2 cross-section has been built to study the drying of lignite. The fluidised bed dryer with tube bundles was used to investigate the scale-up effect on the drying rate of the pulsed flow using superheated steam as the drying medium. Particle agglomeration was found to be a serious problem when increasing the size of the dryer. Agglomeration could be reduced by enhancing the drying rate by increasing the horizontal diffusion rate with the pulsation-assisted flow. It was found that pulsation-assisted flow enhanced the drying rate by nearly 40% compared to that of the steady flow at a gas velocity of 0.29 m/s, and 20% at a gas velocity of 0.19 m/s. The frequency of pulsed flow also affected the drying rate, with 3 and 5 Hz pulsed flow having a higher drying rate than that of 1 Hz.

Rare earth-bearing slag was obtained from the battery wastes by H2 selective reduction and melting separation. The slag contained 46.44 wt% rare earth oxides, 26.05 wt% SiO2, 17.68 wt% Al2O3 and 6.32 wt% MnO. The influence of different reacting factors on the leaching rate of rare earth was investigated, and the leaching dynamics analysed at low temperature and ordinary pressure, and at high temperature and pressure. The optimal leaching parameters for low-temperature/ordinary pressure conditions were 2.69 mol/L hydrochloric acid, 10:1 liquid to solid ratio at 85 degrees C for 75 min and the rare-earth leaching rate reaching 94.94%. The apparent activation energy was 57.68 kJ/mol, the pre-exponential factor was 5.02 × 104 s−1, and the related reaction orders of the hydrochloric acid concentration and particle size were 3.63 and −1.59, respectively. For the high-pressure/high-temperature leaching process, the optimal conditions were 2.49 mol/L hydrochloric acid, 10:1 liquid to solid ratio at 130 degrees C for 25 min and the rare-earth leaching rate 96.70%. The apparent activation energy was 53.63 kJ/mol, and the pre-exponential factor was 5.32 × 103 s−1. The two leaching processes were both controlled by the interfacial mass transfer and solid film diffusion., Rare earth-bearing slag was obtained from the battery wastes by H2 selective reduction and melting separation. The slag contained 46.44 wt% rare earth oxides, 26.05 wt% SiO2, 17.68 wt% Al2O3 and 6.32 wt% MnO. The influence of different reacting factors on the leaching rate of rare earth was investigated, and the leaching dynamics analysed at low temperature and ordinary pressure, and at high temperature and pressure. The optimal leaching parameters for low-temperature/ordinary pressure conditions were 2.69 mol/L hydrochloric acid, 10:1 liquid to solid ratio at 85 degrees C for 75 min and the rare-earth leaching rate reaching 94.94%. The apparent activation energy was 57.68 kJ/mol, the pre-exponential factor was 5.02 × 104 s−1, and the related reaction orders of the hydrochloric acid concentration and particle size were 3.63 and −1.59, respectively. For the high-pressure/high-temperature leaching process, the optimal conditions were 2.49 mol/L hydrochloric acid, 10:1 liquid to solid ratio at 130 degrees C for 25 min and the rare-earth leaching rate 96.70%. The apparent activation energy was 53.63 kJ/mol, and the pre-exponential factor was 5.32 × 103 s−1. The two leaching processes were both controlled by the interfacial mass transfer and solid film diffusion.

Laboratory-scale experiments have been carried out on the utilisation of Indian high ash non-coking coal (NCC) and imported semi-coking coal (SCC) for coke preparation. The washability characteristics of Indian high ash coal were investigated using jigging, spiral concentration, and sink and float density separation methods. The optimum cut-off density NCC and SCC coals were blended and caking properties analysed. Proximate and ultimate analysis, vitrinite reflectance, crucible swelling number, and caking index or roga index have been taken as the measure for the caking ability of coal blends. The results show that jigging and spiral concentration were less effective for the beneficiation of the high ash coals. Regression analysis of two different samples of blended NCC and SCC coals showed there is a negative correlation between the percentage of NCC coal in the blends and reflectance of the blends., Laboratory-scale experiments have been carried out on the utilisation of Indian high ash non-coking coal (NCC) and imported semi-coking coal (SCC) for coke preparation. The washability characteristics of Indian high ash coal were investigated using jigging, spiral concentration, and sink and float density separation methods. The optimum cut-off density NCC and SCC coals were blended and caking properties analysed. Proximate and ultimate analysis, vitrinite reflectance, crucible swelling number, and caking index or roga index have been taken as the measure for the caking ability of coal blends. The results show that jigging and spiral concentration were less effective for the beneficiation of the high ash coals. Regression analysis of two different samples of blended NCC and SCC coals showed there is a negative correlation between the percentage of NCC coal in the blends and reflectance of the blends.

High alumina haematite iron ore fines from three mines in Odisha and Chhattisgarh (India) were used to study the effects of gangue content, type of haematite present, and addition of binders on the properties of iron ore pellets. Molasses and bentonite were used as binders. The effects of binder addition and firing temperature and time on compressive strength, porosity and XRD analysis of the resultant pellets were investigated. The results showed that the amount of Al2O3 in the iron ore pellets had little effect on compressive strength (less than 100 N) and porosity up to 1373 K, followed by a gradual change in their values with further rise of firing temperature up to 1573 K. The X-ray diffraction patterns of resultant fired haematite iron ore pellets did not show any change in the major phase., High alumina haematite iron ore fines from three mines in Odisha and Chhattisgarh (India) were used to study the effects of gangue content, type of haematite present, and addition of binders on the properties of iron ore pellets. Molasses and bentonite were used as binders. The effects of binder addition and firing temperature and time on compressive strength, porosity and XRD analysis of the resultant pellets were investigated. The results showed that the amount of Al2O3 in the iron ore pellets had little effect on compressive strength (less than 100 N) and porosity up to 1373 K, followed by a gradual change in their values with further rise of firing temperature up to 1573 K. The X-ray diffraction patterns of resultant fired haematite iron ore pellets did not show any change in the major phase.

As deep-sea sediment has a higher water content and lower shear strength than land-based soil, mining with crawler mineral collectors is liable to result in slipping and reduced efficiency. Bionic principles that mimic unique animal structures are widely used to solve such engineering problems, the profile of a buffalo hoof having proved key to optimising paddy-field tractors. A rate-dependent extended Drucker-Pager model is used to define the deep-sea sediment and an arbitrary Lagrange-Euler finite-element model to simulate the cutting of different bionic grousers at different speeds. The maximum traction is shown to be related to the curvature change point and curvature radium of the grouser; a binary quadratic regression equation between maximum traction and grouser parameters is established and the best paramters obtained by an optimisation algorithm., As deep-sea sediment has a higher water content and lower shear strength than land-based soil, mining with crawler mineral collectors is liable to result in slipping and reduced efficiency. Bionic principles that mimic unique animal structures are widely used to solve such engineering problems, the profile of a buffalo hoof having proved key to optimising paddy-field tractors. A rate-dependent extended Drucker-Pager model is used to define the deep-sea sediment and an arbitrary Lagrange-Euler finite-element model to simulate the cutting of different bionic grousers at different speeds. The maximum traction is shown to be related to the curvature change point and curvature radium of the grouser; a binary quadratic regression equation between maximum traction and grouser parameters is established and the best paramters obtained by an optimisation algorithm.

Studies have been carried out of the factors influencing the flotation of copper, lead and zinc from a copper oxide-sulphide ore from the Zanjan Province, Iran. The sample was a mixture of quartz, chalcopyrite, galena, cerussite, hemimorphite and iron oxide minerals with 5.04% CuO, 1.61% PbO, 2.07% ZnO and 56.40% SiO2. The effects of pH, collector, depressant, dispersant, preparation time and particle size on Cu-Pb-Zn minerals flotation were studied for three different steps: sulphide bulk flotation, oxide bulk flotation and sulphide differential flotation. The results showed that variation in pH, potassium amyl xanthate and sodium silicate influenced recoveries. In the first step, recovery of Cu-Pb sulphide reached 45.49% with grade of 15.96% for Cu and 61.65% with grade of 7.4% for Pb. In the third step, the recovery and grade of Cu increased to 88% and 18.3%, respectively. The response surface methodology was used to optimise processing parameters, and supplementary tests were carried out under the optimal conditions. This gave recoveries of 88% Cu with grade of 24.5% in Cu concentrate and 81% Pb with grade of 13.8% in Pb concentrate., Studies have been carried out of the factors influencing the flotation of copper, lead and zinc from a copper oxide-sulphide ore from the Zanjan Province, Iran. The sample was a mixture of quartz, chalcopyrite, galena, cerussite, hemimorphite and iron oxide minerals with 5.04% CuO, 1.61% PbO, 2.07% ZnO and 56.40% SiO2. The effects of pH, collector, depressant, dispersant, preparation time and particle size on Cu-Pb-Zn minerals flotation were studied for three different steps: sulphide bulk flotation, oxide bulk flotation and sulphide differential flotation. The results showed that variation in pH, potassium amyl xanthate and sodium silicate influenced recoveries. In the first step, recovery of Cu-Pb sulphide reached 45.49% with grade of 15.96% for Cu and 61.65% with grade of 7.4% for Pb. In the third step, the recovery and grade of Cu increased to 88% and 18.3%, respectively. The response surface methodology was used to optimise processing parameters, and supplementary tests were carried out under the optimal conditions. This gave recoveries of 88% Cu with grade of 24.5% in Cu concentrate and 81% Pb with grade of 13.8% in Pb concentrate.

Cyphos IL 101 is a trihexyl (tetradecyl) phosphonium chloride ionic liquid. Extraction parameters such as equilibration period, acid concentration, chloride ion concentration, and hydrogen ion concentration were examined on the extraction efficiency of Cyphos IL 101 towards In(III). Quantitative extraction of indium was found at 2.0 mol/L HCl using 0.005 mol/L Cyphos IL 101 and quantitative stripping with 1.0 mol/L H2SO4. Cyphos IL 101 was further tested for the removal of indium, tin and copper from the leach liquors of waste LCDs. Two stages at O/A ratio of 1:3 were required for complete removal of tin from the feed. Selective stripping of In and Sn from the loaded organic phase was achieved using 0.1 mol/L H2SO4, with recoveries of 99.1% of In and 99.7% of Sn. A complete flowsheet has been developed for the process., Cyphos IL 101 is a trihexyl (tetradecyl) phosphonium chloride ionic liquid. Extraction parameters such as equilibration period, acid concentration, chloride ion concentration, and hydrogen ion concentration were examined on the extraction efficiency of Cyphos IL 101 towards In(III). Quantitative extraction of indium was found at 2.0 mol/L HCl using 0.005 mol/L Cyphos IL 101 and quantitative stripping with 1.0 mol/L H2SO4. Cyphos IL 101 was further tested for the removal of indium, tin and copper from the leach liquors of waste LCDs. Two stages at O/A ratio of 1:3 were required for complete removal of tin from the feed. Selective stripping of In and Sn from the loaded organic phase was achieved using 0.1 mol/L H2SO4, with recoveries of 99.1% of In and 99.7% of Sn. A complete flowsheet has been developed for the process.

Manganese ore smelting is reviewed in terms of processing parameters such as feed material particle sizes, energy input methods, heat transfer modes, smelting mechanisms, experimental findings on specific smelting aspects, and rates of MnO reduction and carbon dissolution into ferrous alloys. This paper provides a comprehensive current review of our fundamental understanding of manganese ore smelting. Process parameters and resultant cost effects are discussed in terms of existing industrial smelting processes, the Submerged Arc Furnace (SAF) and the Blast Furnace (BF), and the AlloyStream process demonstration plant. Bench-scale experimental results for AlloyStream induction furnace smelting are discussed with reference to rate measurements reported in literature. The experimental results clearly illustrate the importance of higher alloy bath temperatures in induction smelting to improve alloy production rates, whilst the effect of alloy bath chemistry was of less importance. AlloyStream process benefits and issues are discussed with reference to the SAF and BF processes. (Author.), Manganese ore smelting is reviewed in terms of processing parameters such as feed material particle sizes, energy input methods, heat transfer modes, smelting mechanisms, experimental findings on specific smelting aspects, and rates of MnO reduction and carbon dissolution into ferrous alloys. This paper provides a comprehensive current review of our fundamental understanding of manganese ore smelting. Process parameters and resultant cost effects are discussed in terms of existing industrial smelting processes, the Submerged Arc Furnace (SAF) and the Blast Furnace (BF), and the AlloyStream process demonstration plant. Bench-scale experimental results for AlloyStream induction furnace smelting are discussed with reference to rate measurements reported in literature. The experimental results clearly illustrate the importance of higher alloy bath temperatures in induction smelting to improve alloy production rates, whilst the effect of alloy bath chemistry was of less importance. AlloyStream process benefits and issues are discussed with reference to the SAF and BF processes. (Author.)

Reliable models of a metallurgical process should be based on first principles and contain carefully studied and understood component steps. The correctness of assumptions made in the formulation of a mathematical model should be carefully examined to avoid the erroneous application of a model. Discussion is presented of the general approach to mathematical modelling. The constitutive components of the process which should be considered are: physical, transport and chemical properties; mass and heat transfer processes; and heterogeneous chemical reactions and mass transfer. Once individual metallurgical processing steps have been selected they must be interconnected to form a flowsheet for further mathematical modelling. Reaction engineering models are discussed, including: the reaction of an initially non-porous solid (the shrinking-core system), reactions involving an initially porous solid, Sohn's law of additive reaction times, gas-solid traction-rate enhancement by pressure cycling, and complex fluid-solid reactions. Examples of modelling for flash smelting, fluidised-bed reactors, and bottom-gas-injected solvent extraction are presented. Thermodynamic equilibrium process modelling for smelting and computational fluid dynamics modelling are also discussed. The use of physical models to understand aspects of highly complex processes associated with harsh conditions is briefly considered., Reliable models of a metallurgical process should be based on first principles and contain carefully studied and understood component steps. The correctness of assumptions made in the formulation of a mathematical model should be carefully examined to avoid the erroneous application of a model. Discussion is presented of the general approach to mathematical modelling. The constitutive components of the process which should be considered are: physical, transport and chemical properties; mass and heat transfer processes; and heterogeneous chemical reactions and mass transfer. Once individual metallurgical processing steps have been selected they must be interconnected to form a flowsheet for further mathematical modelling. Reaction engineering models are discussed, including: the reaction of an initially non-porous solid (the shrinking-core system), reactions involving an initially porous solid, Sohn's law of additive reaction times, gas-solid traction-rate enhancement by pressure cycling, and complex fluid-solid reactions. Examples of modelling for flash smelting, fluidised-bed reactors, and bottom-gas-injected solvent extraction are presented. Thermodynamic equilibrium process modelling for smelting and computational fluid dynamics modelling are also discussed. The use of physical models to understand aspects of highly complex processes associated with harsh conditions is briefly considered.