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During the roasting process, siderite (FeCO3) transforms to magnetite (Fe3O4) along with producing carbon monoxide (CO), but hematite (Fe2O3) needs CO to reduce into magnetite. The process of simultaneously roasting and magnetic separation was developed to treat the low grade siderite and hematite ores without adding any reductant. Effect of mass ratio of S-to-H (siderite ore to hematite ore) on the separation indexes of iron concentrate was discussed. X-ray diffraction was also employed to detect the phase transformations of roasted ores. The technology of simultaneously roasting and magnetic separation is an effective way to treat low grade siderite and hematite ores, and also reduce the emission of CO2because no ruductant is added. [ABSTRACT FROM PUBLISHER]

To improve the hydrogen-rich gas-based direct reduction to promote green ironmaking, the influence of basicity (CaO/SiO 2) on the consolidation characteristics and hydrogen-rich reduction behaviors of hematite pellets was investigated. The results show that increasing the basicity of hematite pellets can improve their firing performance and reduction behaviors in hydrogen-rich gas. With the rise of pellets basicity from 0.02 to 0.40, the higher compressive strength of fired pellets and the shorter roasting time were achieved. The maximum RSI decreased from 23% to 17% during hydrogen-rich reduction, while the compressive strength increased from 500 to 1070 N/pellet. Mechanism analysis shows that the liquid phase with suitable viscosity not only facilitated the consolidation of hematite pellets, but also desynchronized the volume expansion of the inner and outer layers in the reduced pellets, leading to good resistance against reduction stress and the higher compressive strength of reduced pellets. [Display omitted] • The improved firing performance of hematite pellets by modifying basicity. • The effect of basicity on the reduction behavior of hematite pellets in H 2 -rich gases. • The best H 2 -rich gas-based reduction behavior of hematite pellets with 0.40 basicity. • The desynchronized swelling in the core and edge of pellets by proper liquid phase. [ABSTRACT FROM AUTHOR]

Parallel experimentation allowing comparison of magnetite–hematite–goethite inland and hematite–goethite coastal mill blends in terms of sintering performance is reported. Magnetite–hematite–goethite blend affords slightly lower productivity, tumble index, and yield than hematite–goethite blend. However, magnetite–hematite–goethite blend required 9.2 kg · t−1lower solid fuel rate than the hematite–goethite blend. The lower sintering temperature of the magnetite–hematite–goethite blend than that of the hematite–goethite blend contributed to higher reducibility and lower low temperature degradation under reduction. Its sinter product also contained lower proportions of columnar silico-ferrite of calcium and alumina, magnetite, and fayalite. [ABSTRACT FROM PUBLISHER]

40Ar/39Ar ages were determined for 6 phlogopite samples from a kamafugite pipe occurring in western Qinling, yielding a time span of 22 to 23 Ma for kamafugite eruption. Together with known geochronological data for the Qinghai-Tibet Plateau (QTP) and its peripheral regions, it is concluded that these Cenozoic potassic-ultrapotassic volcanic rocks are products of post-collisional volcanism. The age of the Cenozoic volcanic rocks in western Qinling partly overlaps that of potassic volcanics from the Gandise belt, reflecting the northward migration of the post-collisional volcanism in QTP. The age data not only confirm the temporal and spatial migration of post-collisional volcanism in QTP, but also provide geochronological constraints on the geodynamic setting at depth and the regimes of the tectonic evolution since Neogene in western Qinling regions. [ABSTRACT FROM AUTHOR]

Copper slag, generated mainly during copper smelting, and classified as a potentially harmful waste, is an important secondary resource containing not only valuable metals, such as Cu, Fe, Zn, Co and Ni, in abundant quantities, but also hazardous elements, such as Pb and As. Hence, in response of its potential economic performances and environmental benefits, copper slag needs to be subjected to further metallurgical recycling and cleaning instead of being dumped or abandoned without treatment. Here, a critical review of the generation mechanism, and chemical and physical characteristics of copper slag is provided. Details of the mainstream and recently developed routes for metallurgical recycling and further cleaning of copper slag are also summarised, such as flotation, leaching, and reduction roasting followed by magnetic separation, smelting reduction, and molten modification followed by physical separation. The technical challenges and developmental bottlenecks of the metallurgical processes are pointed out, which indicate that the improved processes characterised by high recycling efficiency, low energy consumption, and low secondary environmental pollution continue to be the focus of research and development in sustainable waste utilization of copper slag. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Red mud is one kind of by-products rejected from industrial production of alumina plant and characterized by high content of alkaline and containing many valuable metals such as iron, aluminum, titanium, etc. It is urgent to effectively utilize red mud for the sustainable development of aluminum metallurgy industry. In this paper, a new route was proposed to fully recover Fe, Al 2 O 3 and TiO 2 from the red mud, which includes three procedures, i.e. pre-reducing-smelting, alkaline leaching and acid leaching. The pre-reducing-smelting step was employed to recover iron from the mud, producing pig iron at an iron recovery of some 98.15% and slag containing 43.17%Al 2 O 3 and 15.71%TiO 2 , respectively. Then, based on the thermal dynamic calculations, a modification of the slag-alkaline leaching and hydrochloric acid leaching process were conducted to obtain the stepwise recovery of Al 2 O 3 and TiO 2 , respectively, from the smelting slag. Aluminum and titanium were recovered in the form of sodium aluminum solution and perovskite at a recovery of 85.85% and 95.53%, respectively. The innovative route is probably a potential way to achieve comprehensive and clean utilization of red mud. [ABSTRACT FROM AUTHOR]

In this study, a novel process was established for extraction of Fe and Al from a complex high aluminum iron ore (33.43% Fetotal and 19.09% Al2O3). The main steps in the proposed process included pre-reducing high alumina iron ore and subsequent smelting to produce pig iron and rich-alumina slag, followed by alkaline leaching of the slag to obtain sodium aluminate solution and a clean slag. When smelting the pre-reduced high alumina iron ore pellets at 1625 °C for 30 min with a slag basicity of 0.40, the pig iron yielded 97.08% Fe and extracted 0.13% Al2O3, together with an iron recovery of 94.54%. In addition, more than 68.93% Al2O3 was recovered by leaching the slag, which was achieved by firstly roasted the slag at 900 °C for 2 h and then alkaline leaching at 95 °C for 2 h with a liquid-to-solid ratio of 10 mL/g. In addition, the alkaline leaching slag could potentially be used as raw material for construction purpose, which mainly consisted of SiO2 and CaO. [ABSTRACT FROM AUTHOR]

Iron ore sinter is one of most extensively utilised ferrous burdens for blast furnace (BF) worldwide. The sinter quality greatly depends on the microstructure and chemical compositions of calcium ferrites which is significantly affected by sinter basicity (mass ratio of CaO to SiO2). The characterisation of iron ore sinter products with varying binary basicity (CaO/SiO2) from 1.5 to 2.7 was studied by using optical microscopy and scanning electron microscopy-energy spectrometer (SEM-EDS). The results show that the change of sinter basicity changes the microstructure and composition of silico-ferrite of calcium and aluminium (SFCA), and more dendritic shape composite calcium ferrite (SFCA) with Fe-rich/low-Si is generated. Under the optical microscope, statistical results of the sinter reveal that with the increase in basicity, the aspect ratio of calcium ferrite increases from 2.35 to 7.69, indicating a gradual refinement of the crystals. Moreover, the distribution of crystals becomes more uniform, and the size of pores between crystals also decreases gradually, thereby the mechanical properties of the sinter from a microscopic structural perspective being enhanced. SEM-EDS analysis studies have found a certain linear relationship between the aspect ratio of SFCA and its iron content, where higher iron content in SFCA leads to finer and narrower SFCA formations. Additionally, an increase in basicity favours the generation of more composite calcium ferrite (SFCA) with Fe-rich/low-Si characteristics, which significantly improves the reducibility of the sinter. Moreover, what is even more interesting is that the iron content in SFCA shows an inverse relationship with the content of silicon, calcium and aluminium elements, yet it is directly proportional to the quaternary basicity [(CaO + MgO)/(SiO2 + Al2O3)] in SFCA. [ABSTRACT FROM AUTHOR]

The utilization of sulfur acid residue is an urgent problem confronting sulfuric acid production enterprises, especially the application of sulfur acid residue (SAR) containing lead and zinc. A method combining chlorination roasting using CaCl2 with pelletizing for processing SAR containing lead and zinc was used in this study, and the effect of calcium chloride on pelletizing performance was studied; in addition, the removal behavior of lead and zinc was also studied by using polarized light microscopy (Zeiss double Axioskop 40A), X ray diffraction, SEM and EDS. The results showed that CaCl2 migrated to the surface of the pellets during drying, and this phenomenon resulted in a lower removal rate of lead and zinc inside the pellets than outside the pellets during the preheating phase. When the roasting temperature was 1220 °C, with an increase in the basicity of pellets, the silicate minerals in the pellets gradually decomposed, the hematite particles were gradually refined, and more lead or zinc minerals were exposed, which further increased the removal rate of lead and zinc in the pellets. Finally, the SAR pellets with Pb and Zn removal rates up to 91.33 and 97.88%, and a compressive strength of 2789 N, could be obtained, which is very beneficial to the sustainable development of sulfuric acid mills. [ABSTRACT FROM AUTHOR]

How to utilize low grade complex iron resources is an issue that has attracted much attention due to the continuous and huge consumption of iron ores in China. High-aluminum iron ore is a refractory resource and is difficult to upgrade by separating iron and alumina. An innovative technology involving synergistic reducing and synergistic smelting a high-aluminum iron ore containing 41.92% Fetotal, 13.74% Al2O3, and 13.96% SiO2 with a high-manganese iron ore assaying 9.24% Mntotal is proposed. The synergistic reduction process is presented and its enhancing mechanism is discussed. The results show that the generation of hercynite (FeAl2O4) and fayalite (Fe2SiO4) leads to a low metallization degree of 66.49% of the high-aluminum iron ore. Over 90% of the metallization degree is obtained by synergistic reducing with 60% of the high-manganese iron ore. The mechanism of synergistic reduction can be described as follows: MnO from the high-manganese ore chemically combines with Fe2SiO4 and FeAl2O4 to generate Mn2SiO4, MnAl2O4 and FeO, resulting in higher activity of FeO, which can be reduced to Fe in a CO atmosphere. The main products of the synergistic reduction process consist of Fe, Mn2SiO4, and MnAl2O4. [ABSTRACT FROM AUTHOR]

Oxidised pellets have become an indispensable high-quality charge for blast furnaces. Nevertheless, high-quality pellet feeds are becoming scarcer and scarcer. To broaden the range of sources of pellet feeds and reduce the production cost of pellets, more steel mills are predicted to use coarse iron ore fines with a relatively low iron grade and low impurities for the preparation of desirable pellet feeds through a typical wet grinding–settling–filtering process. In this work, the grinding, settling and filtering behaviour of Brazilian and Australian iron ore fines are studied and compared, with the aim of discovering the internal relationship between the mineralogical characteristics of different iron ore types and their grinding–settling–filtering performance. Additionally, the effects of ore blending on pellet preparation were investigated. The results show that, usually, the higher the hardness of the iron ore, the more grinding energy is required. Australian and Brazilian ore fines exhibit good grindability, with a Bond work index of about 10–15 kW·h/t. Furthermore, ore blending can reduce grinding energy consumption and improve settling and filtration rates, and the addition of finely ground Australian ores improves the balling performance of pellet mixtures. At the same bentonite content, the ball drop strength of the three blends with added Australian ore is significantly higher than that of the base blend, and the fired pellets obtained from Blend 1, Blend 2 and Blend 3 blends exhibit good metallurgical properties. [ABSTRACT FROM AUTHOR]

Vanadium titanomagnetite (VTM) pellets is an important charge for utilizing VTM through the rotary kiln-electric furnace process, and its reduction characteristic is essential to industrial production. This paper investigated the reduction behaviors and mechanism of three types of fired VTM pellets, i.e. PA, PB and PC with 13.02%, 11.70% and 5.25% TiO 2 , respectively. Under the optimal conditions, which were reduced at 1423 K for 150, 120 and 100 min, respectively, they obtained more than 90% reduction degree. During reduction, PA exhibited excellent resistance to volume swelling and great morphology, while PB and PC displayed abnormal swelling and structural damage. Kinetic and microstructure studies indicated that the reduction of PA, which consisted of titanohematite and pseudobrookite, was controlled by the random nucleation and subsequent growth of metallic iron, whereas that of PB and PC, which mainly contained titanohematite, was controlled by intrinsic chemical reactions. Iron- and titanium-bearing oxides were reduced to metallic iron via two routes: titanohematite → titanomagnetite → wustite → metallic iron and pseudobrookite → metallic iron. These various compositions and grain sizes of iron- and titanium-bearing oxides led to different generation rates and morphologies of metallic iron, directly affecting the reduction characteristics and macroscopic performance of VTM pellets. • The reduction characteristics of three representative types VTM pellets are studied. • The reduction degree above 90% was obtained at 1423 K for all the pellets. • Highly diverse swelling and strength was seen in reduction of distinct types pellets. • The reduction kinetics and paths to generate Fe vary quite in distinct types pellets. • The microstructure evolution greatly affects the macroscopic reduction behaviors. [ABSTRACT FROM AUTHOR]

In this work, a new hydrometallurgical process was developed to treat zinc ash produced from the hot galvanizing industry. The theoretical analysis shows the feasibility of dissolving zinc ash in the NH3–NH4Cl–H2O system, and the dissolution products are predominantly composed of Zn (NH3)42+. The impacts of different experimental conditions were examined, and the leaching ratio of zinc was as high as 96.4% under the conditions of NH3/NH4+ ratio of 1:1, liquid/solid of 9:1, total ammonia concentration of 8 mol/L and the stirring speed of 250 rpm at 313 K for 120 min. The kinetics of the leaching process were investigated and the calculated apparent activation energy was approximately 4.69 kJ/mol, which indicated that the zinc ash leaching process was controlled by diffusion-controlled. As revealed by the determination of impurity ions, on one hand, there were fewer impurities in the leaching solution, and the concentrations of Fe2+ and Pb2+ in solution are less than 0.02 mg/L and 0.05 mg/L respectively; on the other hand, there was no need for further impurity removal in this process. The proposed process has a certain application value in treating zinc ash. [ABSTRACT FROM AUTHOR]

An innovative one-step process for activated carbon production from low-rank coal is proposed in this research by applying oxidized pellets as activator. The new process can realize synchronous production of the activated carbon and direct reduction iron through combination of carbonization and activation of low-rank coal in one step while no solid wastes were discharged. The desulfurization and denitrification performance of the obtained activated carbon was also evaluated on the simulative sintering flue gas in comparison with one type of commercial activated carbon. The results indicated that a superior activated carbon with high specific surface area of 370.42 m2 g−1, iodine sorption value of 695.13 mg g−1, compressive strength of 315 N·per−1and abrasive resistance of 96.61%, can be prepared under suitable conditions of activation temperature at 850 °C for 140 min with C/Fe mass ratio of 2.5. Meanwhile, the direct reduction iron has a metallization ratio of 88.31%. The activated carbon has a preferable desulfurization performance with the breakthrough sulfur capacity of 5.463 mg/g and breakthrough time of 46.33 min, and single denitrification performance with the breakthrough nitric capacity of 1.935 mg/g and breakthrough time of 90.17 min at flue gas temperature of 80 °C, airspeed ratio of 8370 h−1, gas flow of 1.8 m3/h, and oxygen concentration of 16%. The denitrification of activated carbon in the simultaneous desulfurization and denitrification process can be improved by catalytic reduction via the transformation from NO to N 2. The good results show that this process has a bright future with high technical and economic feasibility. [Display omitted] • An innovative one-step process for production of activated carbon was proposed. • Synchronous production of direct reduction iron realized an extra economic benefit. • Performance on removal of SO 2 and NO X from sintering flue gas was analyzed. • Mechanism on desulfurization and denitrification of activated carbon was disclosed. • Catalytic reduction for improved denitrification of activated carbon was revealed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Utilizes titanium extraction tailing as a sustainable source for high-quality iron phosphate production. • Efficient separation of iron and titanium is achieved through co-leaching. • The contents of impurities in the product were far below the standard. • Formation of [Fe(HPO 4) 2 ]- complexes in acid leaching promotes iron dissolution, enhancing the efficiency of iron extraction. This study presents a compelling, eco-friendly methodology for extracting valuable materials from titanium extraction tailing (TET) discharged from the reduction rust process. The process efficiently separates titanium and iron by utilizing a co-leaching technique with sulfuric and phosphoric acids. This method results in a high-grade titanium dioxide (TiO 2) with a purity of 61.57 % and an iron leaching rate surpassing 96 % under the optimal conditions of the liquid-to-solid ratio of 4:1, a leaching temperature of 70 °C, and a specific phosphoric acid to iron molar ratio is 1.1. The subsequent refinement phase involves adjusting the pH to 2.0 using ammonia, coupled with controlled precipitation temperature and ageing time, leading to the production of battery-grade iron phosphate (FePO 4) with a purity of 98.82 %, in line with the stringent HG/T4701-2014 standards. The material's phase analysis and morphological characterization confirm its high crystallinity and minimal impurity levels. Moreover, the co-leaching approach facilitates magnetite dissolution, effectively enriching the rutile content in the leach residue and concurrently minimizing the formation of ammonium sulfate salts, thereby enhancing the purity of the iron phosphate. These technological advancements contribute to resource recovery research and offer new avenues for industrial material production, laying a solid foundation for sustainable industrial applications. [ABSTRACT FROM AUTHOR]

In this study, the isothermal oxidation kinetics of magnetite (OM), high-Mg magnetite (MM), titanomagnetite (TM), and chromite (CM) were investigated by applying thermogravimetry (TG) analysis at temperatures ranging from 1073 K to 1223 K. The results show that different high-FeO spinels possess distinct oxidizability. The oxidation process of OM in the temperature range from 1073 K to 1223 K is faster than others, followed by MM and TM. While CM exhibits the poorest oxidizability, and generally undergoes complex phase transitions. In the initial stage of oxidation, high FeO spinels have a higher oxidation rate due to the surface oxidation of spinel particles. However, the oxidation rate gradually declines in the later stages of oxidation due to increased internal diffusion resistance. The results of oxidation kinetics indicate that the initial oxidation stage of four spinels can be described as random nucleation and subsequent growth mechanism. The average apparent activation energies of the initial oxidation stage of OM, MM, TM, and CM are 25.09 kJ/mol, 32.39 kJ/mol, 58.10 kJ/mol, and 82.42 kJ/mol, respectively. [ABSTRACT FROM AUTHOR]

In this paper, an innovative method is proposed to upgrade iron and remove phosphorus from high-phosphorus oolitic hematite ore by the sodium magnetization roasting–magnetic separation–sulfuric acid and sodium hydroxide leaching process. The process parameters of sodium magnetization roasting, acid leaching, and alkaline leaching were optimized. The results show that by only adopting traditional magnetization roasting–magnetic separation, an iron ore concentrate containing 57.49% Fe and 1.4% P2O5 at an iron recovery rate of 87.5% and a dephosphorization rate of 34.27% was produced, indicating that it is difficult to effectively dephosphorize and upgrade iron by the conventional magnetization roasting–magnetic separation process. The obtained rough magnetic concentrates were then subjected to acid and alkaline leaching steps, and the final product, assayed at 64.11% iron and 0.097% P2O5, was manufactured successfully. Moreover, the added NaOH could promote the mineral phase reconstruction of aluminum- and silica-bearing minerals during magnetization roasting and intensify the upgrading of iron as well as enhance the growth of iron grains. [ABSTRACT FROM AUTHOR]

An innovative technical route has been proposed to improve recycling efficiency of Ni and Fe from low-grade nickel laterite via the duplex process between direct reduction-magnetic separation and rotary kiln-electric furnace. The results indicated that the high‑nickel concentrates produced from direct reduction-magnetic separation process, which were combined with optimization of slag types can not only increase the grade of furnace burdens and decrease quantity of slag, but also improve the fluidity of slag and smelting efficiency as well as reduce the power consumption of smelting. For the industrial application of duplex process, a preferable stainless-steel master alloy with 10.02% Ni was obtained at a lower cost of 8420 RMB/t than that of 8731 RMB/t for a stainless-steel master alloy containing 8.14% Ni in conventional rotary kiln-electric furnace process, and the recovery of nickel also increased from 91.27% to 95.51%, which shows an obvious superiority for treating the low-grade nickel laterite. [Display omitted] • An effective and economical way for processing low-grade nickel laterite was proposed. • The strengthening mechanism of DRMS-RKEF for recycling Ni and Fe was revealed. • The performance and prospect of DRMS-RKEF into industrial application were clarified. [ABSTRACT FROM AUTHOR]

Nickel saving austenite crude stainless steel master alloys were innovatively produced by smelting of nickel‑chromium‑manganese bearing prereduced pellets in an effective and economical way. The thermodynamics analysis and systematic process mineralogy were also conducted to further reveal the smelting characteristics of prereduced pellets and the related enhanced mechanism. The results showed that the preferable stainless steel master alloys with 66.29% Fe, 4.21% Ni, 17.28% Cr, 6.53% Mn and 4.76% C can be prepared from the nickel‑chromium‑manganese bearing prereduced pellets with a corresponding recovery of valuable metals more than 95%. Furthermore, during the enhanced smelting process, the optimization of slag types can further realize the phases transformation from high-melting-point enstatite and forsterite to low-melting-point diopside and monticellite to obtain a decreased smelting temperature and viscosity of slag. The smelting duration and the alloy grain included in the smelting slag were both obviously decreased, resulting in an improved smelting performance. [Display omitted] • The smelting characteristics of nickel-chromium-manganese bearing prereduced pellets was clarified; • Thermodynamics analysis on the multicomponent alloy and smelting slag was studied; • Phase transformation and microstructure evolution during smelting process were revealed; • The strengthening mechanism of enhanced smelting process was disclosed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Enhanced reduction and compressive strength of nickel–chromium-manganese reduced pellets was realized. • Thermodynamics analysis of the main metallic oxides was studied. • Phase transformation and microstructure evolution of reduced pellets were clarified. • The mechanism of reduction and consolidation strengthening for the reduced pellets was disclosed. For increasing the reduction degree and compressive strength of nickel–chromium-manganese bearing reduced pellets, the manganese ore and calcium oxide were applied as additives to improve the reduction and consolidation characteristic. The thermodynamics analysis and systematic process mineralogy were also conducted to further determine the related strengthening mechanism. The results showed that compared with no manganese ore and natural basicity, the compressive strength, reduction degree of pellets, iron and nickel for the reduced pellets can reach from 58 N per pellet, 56.21 %, 71.29 % and 91.45 % to 489 N per pellet, 69.58 %, 88.21 % and 98.55 % respectively with 5 % manganese ore and 0.30 binary basicity. MnO and CaO can improve the reduction of iron oxides. Meanwhile, during the reduction process, the low-melting-point phases can generate in the prereduced pellets, which can act as binding phases to wet and tighten the solid particles around through surface tension. The enhanced ways can accelerate the reduction of multi-metal bearing phases, growth of α (Fe, Ni) and solid phase reaction of adjacent particles, resulting in an improvement of reduction degree and compressive strength for the nickel–chromium-manganese bearing reduced pellets. [ABSTRACT FROM AUTHOR]

Manganese ore and CaO were applied as additives to improve the consolidation characteristic of fired nickel‑chromium iron ore pellets. The thermodynamics analysis and systematic process mineralogy were also conducted to further determine the related strengthening mechanism. The results showed that compared with no manganese ore and natural basicity, the compressive strength and porosity of fired pellets varied from 231 N per pellet and 32.45% to 1509 N per pellet and 17.21%, respectively with 6% manganese ore and 0.30 binary basicity. Meanwhile, the low-melting-point phases can generate and amount from 2.18% to 16.24% in the fired pellets, which can act as binding phases to wet the surface of skeleton phases, tighten the solid particles around through surface tension and accelerate recrystallization of hematite and solid phase reaction of adjacent particles, resulting in an improvement of solid phase consolidation and compressive strength for the fired nickel‑chromium‑manganese iron ore pellets. [Display omitted] • The compressive strength of fired nickel-chromium‑manganese iron ore pellets was increased. • Thermodynamics analysis on the raw materials of fired pellets was studied. • Phase transformation and microstructure evolution of fired pellets were clarified. • The mechanism of consolidation strengthening for the fired pellets was disclosed. [ABSTRACT FROM AUTHOR]

Lignosulphonate (LS) is the most commonly used surfactant in zinc pressure leaching (ZPL). In this work, the performance of LS obtained from several producers in ZPL was comparatively studied, the differences in LS characteristics were evaluated in terms of composition, structure, surface tension, etc., and the decomposition behaviour of a typical LS in ZPL was investigated. The results indicated that the leaching performances of these LS varied and depended on the LS characteristics, purity and molecular weight in particular; the differences in the LS characteristics were distinct, and the LS surface activity was the fundamental reason for their diverse leaching performances; softwood and hardwood LS showed superior performances, and three main steps could be concluded for LS decomposition: LS→aromatic compounds (guaiacol, vanillin, vanillic acid, apocynin, etc.)→low molecular organics (short chain ketone, acids, etc.)→CO 2 +H 2 O. The results will help the selection and development of LS dedicated to ZPL, and further promote the efficiency, clean, and stability of zinc production. [Display omitted] • Lignosulphonate's performance and decomposition in zinc pressure leaching were investigated. • Different Zn recovery (64−92%) and lignosulphonate's decomposition (20−65%) were observed. • Characteristics of lignosulphonates from different producers were various. • Lignosulphonate's performance depended on its purity, molecular weight, and surface activity. • Decomposition order: lignosulphonate.→aromatic compounds→low molecular organics→CO 2 +H 2 O. [ABSTRACT FROM AUTHOR]

[Display omitted] • The extraction of Ge(IV) with N235 followed an ion exchange mechanism. • Two coordination compounds were formed between Ge(IV), N235 and tartaric acid. • TOP didn't affect extraction reaction but entered extraction complex by 'O P H'. • K ex , ΔH, ΔS and ΔG of apparent extraction reaction were determined. With the increasing demand for germanium in high-technology fields, the recovery of germanium has gained a great deal of attention. In this study, classical methods (including stoichiometry and saturation methods) were combined with spectroscopic methods (FT-IR, NMR, and ESI-MS) to investigate the mechanism of Ge(IV) extraction from a sulfuric acid solution using the tertiary amines (N235) and trioctyl phosphate (TOP) system. The results indicate that Ge(IV) was extracted as a Ge(OH)(HL) 3 anion complex, and tartaric acid is coordinated to Ge(IV) via a C O bond from the carboxylate group. The extraction process followed an anion exchange mechanism. TOP participated in the formation of extraction complexes through hydrogen bonds in the form of Ge OH⋯O P but did not co-extract germanium with N235. The extracted complex species were Ge(OH)(HL) 2 L·HN(R 1) 3 and Ge(OH)(HL)L 2 ·[HN(R 1) 3 ] 2 (R=C 8 H 17). The apparent equilibrium constants of the extraction reactions K ex were 100.36 and 100.43 at tartaric acid/Ge(IV) ratios of 5 and 3, respectively. The thermodynamic constants for the extraction process were ΔH =−0.457 kJ·mol−1, ΔS =1.176 kJ·mol−1·K−1, and ΔG =−351.081 kJ·mol−1. [ABSTRACT FROM AUTHOR]

[Display omitted] • Zinc and lead in zinc-bearing dusts can be effectively removed by hydrogen reduction. • The zinc and lead removal degree were 96.8 % and 71.1 % at optimal conditions. • Zinc-bearing dusts can be converted to ICME materials through hydrogen reduction. • The COD removal degree was 61.8 % with optimal Fe/C micro-electrolysis material. • The optimal ICME material has developed specific surface area and pore structure. Up to 80 million tons of zinc-bearing dusts are discharged by the steel industry in the word annually, and the traditional pyrometallurgy process of recycling these hazardous wastes with solid carbon as the reducing agent has high energy consumption, large carbon emissions and little added value of products. In this study, we proposed an innovative utilization of zinc-bearing dusts by hydrogen reduction to recover zinc and lead and synergistic prepare iron-carbon micro-electrolysis (ICME) materials for wastewater treatment. The hydrogen reduction behaviors of zinc-bearing dusts pellets were investigated, as well as the properties of the prepared ICME materials (HR) were comprehensively analyzed. The results indicated that the metallization degree, zinc and lead removal degree of zinc-bearing dusts pellets were 98.5 %, 96.8 % and 71.1 %, respectively, under the optimal reduction condition. The synergistic prepared HR with Fe/C of 15:1, specific surface area of 5.158 m2/g and pore volume of 0.01004 cm3/g could remove more than 60 % of COD in wastewater within 2 h. The tight iron-carbon bonding and well-developed pore structure of HR made it equivalent wastewater treatment effects compared to commercial materials. Therefore, the novel process provides a clean and high-value way out for these hazardous wastes. [ABSTRACT FROM AUTHOR]

Owning to the lack of commercial independent germanium deposit and the ever-growing germanium demand of high-tech field, the recovery of germanium from various resources shows strategic significance. In this study, a novel solvent extraction system based on primary amine (N1923) and hydroxycitric acid (HCA) was developed to recover germanium from leaching liquors of secondary zinc oxide and some typical resources. The results indicated that the solvent system showed high extraction efficiency and germanium selectivity; equilibrium pH and the dosage of HCA were the key parameters for germanium recovery, the germanium extraction capacity of an organic phase with 0.24 mol/L N1923 was 7.97 g/L; germanium could be separated from zinc, arsenic, iron, and cadmium at an equilibrium pH of 1.0, and the separation factors of germanium to those elements were up to 1778, 232, 67074, and 14706, respectively; the system was also with well separation performance of germanium from typical germanium containing leachates of copper cake and coal fly ash. Stoichiometry analysis and FT-IR, NMR, and ESI-MS spectra demonstrated that the extraction of germanium followed a coordination anion extraction mechanism, the germanium extraction complexes was RNH 3 ⋅GeO 2 C 6 H 4 O 7. 0.5 mol/L NaOH can be selected for the stripping of germanium.2 [Display omitted] • A novel solvent extraction system for Ge separation was developed and evaluated. • Ge was selectively recovered from leaching liquors of SZO, CFA, Cu cake by N1923. • The extraction behavior of Ge, As, Zn, Cd, Fe by the new system was investigated. • Ge extraction mechanism was discussed via stoichiometry and spectra analyses. [ABSTRACT FROM AUTHOR]

Polycrystalline ZnS is a typical infrared optical material. It is widely used in advanced optical systems due to its excellent optical properties. The machining accuracy of polycrystalline ZnS optical elements must satisfy the requirements of high-performance system development. However, the soft and brittle nature of the material poses a challenge for high-quality and efficient machining. In recent years, in situ laser-assisted diamond cutting has been proven to be an effective method for ultra-precision cutting of brittle materials. In this study, the mechanism of in situ laser-assisted cutting on ultra-precision cutting machinability enhancement of ZnS was investigated. Firstly, the physical properties of ZnS were characterized by high-temperature nanoindentation experiments. The result revealed an increase in ductile machinability of ZnS due to plastic deformation and a decrease in microhardness and Young's modulus at high temperatures. It provided a fundamental theory for the ductile-brittle transition of ZnS. Subsequently, a series of diamond-cutting experiments were carried out to study the removal mechanism of ZnS during in situ laser-assisted cutting. It was found that the mass damage initiation depth groove generated by in situ laser-assisted cutting increased by 57.99% compared to the groove generated by ordinary cutting. It was found that micron-sized pits were suppressed under in situ laser-assisted cutting. The main damage form of HIP-ZnS was changed from flake spalling and pits to radial cleavage cracks. Additionally, the laser can suppress the removal mode difference of different grain crystallographic and ensure the ductile region processing. Finally, planning cutting experiments were carried out to verify that a smooth and uniform surface with Sa of 3.607 nm was achieved at a laser power of 20 W, which was 73.58% better than normal cutting. The main components of roughness were grain boundary steps and submicron pit. This study provides a promising method for ultra-precision cutting of ZnS.

In order to address the low thermal efficiency of low-rank coal combustion and the accompanying serious environmental issues, formed coke was prepared using a carbonization consolidation method with low-rank coal semi-coke. The test for briquetting and carbonation consolidation conditions revealed that the optimal parameters were a briquetting pressure of 93.63 MPa, moisture content of 16%, Ca(OH) 2 binder amount of 10%, and a CO 2 concentration of 30% at 20 °C. Under these conditions and a carbonation consolidation time of 60 min, high-quality formed coke was produced, exhibiting a compressive strength of 1256.2 N/a, redrying strength of 286.2 N/a, and a dropping strength of 10.6 number/a. The combustion characteristics of the prepared formed coke were investigated, revealing that ignition temperatures (345.39 °C), burnout temperatures (495.57 °C), and peak of the maximum weight loss rate temperatures (437.93 °C) are slightly higher than those of bituminous coal. The low calorific value of the briquette was 20.4 MJ/kg. During the combustion process, the emission concentrations of SO 2 , NO X , and solid particles from the formed coke were significantly lower than those of bituminous coal, indicating that it is a cleaner energy source. Moreover, adding Ca(OH) 2 effectively reduced SO 2 emissions and achieved sulfur fixation and emission reduction., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)