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Sea nodules were smelted in the presence of coke to produce an alloy rich in nickel, cobalt, copper and iron. The amount of coke, amount of quartz, smelting temperature and holding time were optimised on a bench scale of 0.5 and 20 kg. On a pilot scale of 250 kg in the presence of 8% coke and 4% quartz and 1 h holding time in a graphite-lined 150 kVA arc furnace, recoveries of 90.4% Cu, 91.7% Ni and 87.8% Co were achieved. As part of the iron (58.8%) was recovered in the alloy, the process generated a slag rich in manganese with a Mn/Fe ratio of about 10, from which standard-grade Fe-Si-Mn was produced. The metal-rich alloy was further processed to recover nickel, cobalt and copper in pure form., Sea nodules were smelted in the presence of coke to produce an alloy rich in nickel, cobalt, copper and iron. The amount of coke, amount of quartz, smelting temperature and holding time were optimised on a bench scale of 0.5 and 20 kg. On a pilot scale of 250 kg in the presence of 8% coke and 4% quartz and 1 h holding time in a graphite-lined 150 kVA arc furnace, recoveries of 90.4% Cu, 91.7% Ni and 87.8% Co were achieved. As part of the iron (58.8%) was recovered in the alloy, the process generated a slag rich in manganese with a Mn/Fe ratio of about 10, from which standard-grade Fe-Si-Mn was produced. The metal-rich alloy was further processed to recover nickel, cobalt and copper in pure form.

An improved mathematical model was developed to simulate the particle and flow behaviour in a coal-washing spiral which takes into account the geometry of the spiral and its trough, fluid motion along the curvilinear path of the spiral and the principal forces acting on a particle incorporating the Bagnold effect. The model components were combined seamlessly by assuming that the particles eventually attain dynamic equilibrium in the forward longitudinal direction and static equilibrium in the transverse direction. The resulting force function provides a spectrum of the radial location of the particles on the trough according to their size and relative specific gravity. The model predicts relative specific gravity distribution as a function of equilibrium radial position for different particle sizes and computes particle size variation as a function of equilibrium radial position for various values of relative specific gravity. The simulation results are reasonably consistent with published data., An improved mathematical model was developed to simulate the particle and flow behaviour in a coal-washing spiral which takes into account the geometry of the spiral and its trough, fluid motion along the curvilinear path of the spiral and the principal forces acting on a particle incorporating the Bagnold effect. The model components were combined seamlessly by assuming that the particles eventually attain dynamic equilibrium in the forward longitudinal direction and static equilibrium in the transverse direction. The resulting force function provides a spectrum of the radial location of the particles on the trough according to their size and relative specific gravity. The model predicts relative specific gravity distribution as a function of equilibrium radial position for different particle sizes and computes particle size variation as a function of equilibrium radial position for various values of relative specific gravity. The simulation results are reasonably consistent with published data.

In situ generation of magnesium by the reduction of its oxide is being considered by researchers as a possible means of effective desulphurisation of liquid iron. Generation of magnesium in this process will be affected by the flow rate of inert gas. The influence of the flow rate of inert gas on the degree of reduction of magnesium oxide by aluminium was studied. The liberation of magnesium increases with increase in flowrate of inert gas. A mathematical model was developed to predict the influence of argon flow rate on the degree of reduction. The reduction was significantly influenced by temperature. Whereas the degree of reduction was about 30% at 1 473 K, it was about 85% at 1 673 K. SEM studies showed that the reduction of the oxide with Al was a complex process. A part of the Mg vapour generated during reduction was trapped inside the (oxide+Al) tablets. Temperature, Ar flow rate and the porosity of the tablets were parameters that critically influenced the degree of reduction., In situ generation of magnesium by the reduction of its oxide is being considered by researchers as a possible means of effective desulphurisation of liquid iron. Generation of magnesium in this process will be affected by the flow rate of inert gas. The influence of the flow rate of inert gas on the degree of reduction of magnesium oxide by aluminium was studied. The liberation of magnesium increases with increase in flowrate of inert gas. A mathematical model was developed to predict the influence of argon flow rate on the degree of reduction. The reduction was significantly influenced by temperature. Whereas the degree of reduction was about 30% at 1 473 K, it was about 85% at 1 673 K. SEM studies showed that the reduction of the oxide with Al was a complex process. A part of the Mg vapour generated during reduction was trapped inside the (oxide+Al) tablets. Temperature, Ar flow rate and the porosity of the tablets were parameters that critically influenced the degree of reduction.

The process of selective reduction of iron in ilmenite and the simultaneous formation of Fe-C alloy melting at low temperatures was investigated. The reduced sample was characterised at each stage using SEM. The influence of temperature, time and additives on the process was studied. It was observed that the size of the alloy particles formed during reduction was strongly influenced by temperature and the morphology of the particles changed significantly with temperature. The size of the particle was c.150 micrometres when reduction was carried out at 1 673 K. The particles were easily detached from the residual matrix of oxide at this temperature. The non-magnetic fraction of the reduced samples contained essentially titanium dioxide. (Authors.), The process of selective reduction of iron in ilmenite and the simultaneous formation of Fe-C alloy melting at low temperatures was investigated. The reduced sample was characterised at each stage using SEM. The influence of temperature, time and additives on the process was studied. It was observed that the size of the alloy particles formed during reduction was strongly influenced by temperature and the morphology of the particles changed significantly with temperature. The size of the particle was c.150 micrometres when reduction was carried out at 1 673 K. The particles were easily detached from the residual matrix of oxide at this temperature. The non-magnetic fraction of the reduced samples contained essentially titanium dioxide. (Authors.)

Contours of iso-reduction lines in the submerged arc furnace producing ferrochromium were constructed using a mathematical model based on the temperature profile inside the furnace and the kinetics of reduction of chromite ores. The location and the contours of the iso-reduction lines are significantly influenced by the temperature profile in the furnace. From the model, it is found that around 27% of the furnace volume is used for the reduction of the ore. The contours are significantly influenced by the degree of pre-reduction of the ore charged into the furnace. The iso-reduction lines can be used for enhancing the efficiency of the process and for better control of the operation exploiting options such as intelligent distribution of charge materials over the charge bed. (Authors.), Contours of iso-reduction lines in the submerged arc furnace producing ferrochromium were constructed using a mathematical model based on the temperature profile inside the furnace and the kinetics of reduction of chromite ores. The location and the contours of the iso-reduction lines are significantly influenced by the temperature profile in the furnace. From the model, it is found that around 27% of the furnace volume is used for the reduction of the ore. The contours are significantly influenced by the degree of pre-reduction of the ore charged into the furnace. The iso-reduction lines can be used for enhancing the efficiency of the process and for better control of the operation exploiting options such as intelligent distribution of charge materials over the charge bed. (Authors.)

Experiments using ore and coke of different sizes found that the reduction mechanism is influenced by the size of both ore particle and coke and is also controlled by the temperature of reduction. At 1 473 K, the reduction is controlled by diffusion for large ore particles but by chemical reaction for smaller ones, whereas at 1 373 K chemical reaction is the controlling mechanism for both large and small ore particles. The relative sizes of ore and coke play a more important role than their actual sizes., Experiments using ore and coke of different sizes found that the reduction mechanism is influenced by the size of both ore particle and coke and is also controlled by the temperature of reduction. At 1 473 K, the reduction is controlled by diffusion for large ore particles but by chemical reaction for smaller ones, whereas at 1 373 K chemical reaction is the controlling mechanism for both large and small ore particles. The relative sizes of ore and coke play a more important role than their actual sizes.