China Nonferrous Metallurgy

Abstract:Aiming at the problem of low calcium and high magnesium in titanium concentrate in Panxi area, this paper uses air supplement and no air supplement to pre-oxidize the titanium concentrate. The mineral composition and microstructure of the roasting products of titanium concentrate with different roasting temperature, roasting time and atmosphere were analyzed by MLA mineral analysis system, and the material characteristics were discussed on this basis. The results show that under the condition of no air supplement, the magnetite in the titanium concentrate is oxidized to hematite, which is dissolved with the unoxidizedilmenite to form titanium hematite, which has a solid solution separation structure. With the increase of roasting temperature, the proportion of intergrowth minerals of ilmenite increases, the proportion of monomer decreases, and the degree of dissociation becomes worse. Under the condition of adding air, the rutile formed by the first crystallization is in his shape, and the particle size is about 6μm. The iron-brookite formed by post-crystallization is self-shaped and semi-self-shaped, and the particle size is about 10μm. Iron brookite encapsulates mineral particles such as rutile, with granular embedded crystal structure, and its dissociation effect is poor. After the oxidation roasting of titanium concentrate, the grain boundaries and pores formed between the minerals improve the metallurgical kinetics and thermodynamic conditions. In contrast, the effect of supplementary air oxidation is better than that of non-supplementary air oxidation. The suitable oxidation roasting parameters are roasting temperature of 1200℃ and holding time of 80min.

Abstract:The acid-soluble titanium slag produced by arc furnace smelting of Panxi ilmenite concentrate has the characteristics of low titanium grade, high magnesium and low calcium. At present, it is mainly used in the preparation of titanium dioxide by sulfuric acid method. In order to extend the industrial structure of Panzhihua titanium, the preparation of Ti- (55~70) wt. % Si alloy was carried out by silicothermic reduction method with the acid-soluble titanium slag as raw material. The slag-metal separation effect and influencing factors of different test schemes were analyzed, as well as the microstructure morphology and metal element distribution of the alloy products. The results show that the slag-metal separation effect of Ti-60wt. % Si alloy melt is the best under the condition of considering alloy superheat and density. The main phases in the alloy are Si phase, TiSi₂ phase, TiFeSi₂ phase and Ti (Fe, Mn)Si₂ phase. Under the best alloy separation effect, the actual alloy composition obtained is Ti-56.29wt. % Si-6.6wt. % Fe-0.41wt. % Mn; the recovery of Ti, Fe, Si and Mn is 89.8%, 93.5%, 92.1% and 94.4%, respectively. The actual alloy composition of acid-soluble titanium slag after silicothermic reduction tends to be hypoeutectic Ti- (51.4 ~ 67.17)wt. %Si, which can provide raw materials for the preparation of C54-TiSi₂ by electromagnetic directional solidification separation. Therefore, this process can expand the use of acid-soluble titanium slag and expand the application of acid-soluble titanium slag to the lower end of the titanium industry chain.

Abstract:In this paper, titanium concentrate and anhydrous potassium carbonate were used as raw materials to synthesize potassium ferrite composites in situ by oxidation roasting process. The roasted products prepared at different roasting temperatures were characterized and their photocatalytic degradation performance was evaluated. The phase composition, valence state, spectral absorption and microscopic morphology of the roasted products were characterized by XRD, XPS, UV-Vis and SEM. The results show that the calcined product after oxidation roasting is mainly composed of potassium ferrite, potassium titanate and potassium titanium ferrite. Potassium ferrite and potassium titanate are unevenly attached to the surface of potassium titanium ferrite crystal; iron and titanium exist in the form of Fe3+ and Ti4+, respectively; When the calcination temperature is 750℃, 850℃ and 950℃, the band gaps of the synthesized potassium titanate composites are 1.25eV, 1.15eV and 1.45eV, respectively; photocatalytic performance test results show that with the increase of calcination temperature, the photocatalytic degradation performance of calcined products for methylene blue first increases and then decreases, and the potassium titanoferrite composites at 850℃ reach the optimum, up to 98.3%; when methyl orange is used as a pollutant, the degradation effect of calcined products is better with the increase of calcination temperature, and the degradation rate can reach 56.6% at 1000℃.

Abstract:Photothermal conversion is an effective solar energy utilization technology, and its efficiency depends on the light absorption capacity of photothermal conversion materials. In this paper, Black TiO₂ steel slag/graphite porous materials were prepared in situ by high temperature calcination with titanium dioxide as raw material, steel slag as skeleton, graphite as reducing agent, starch as pore-forming agent and polyvinyl alcohol solution as binder. The phase, microstructure, surface element composition and valence state and light absorption ability of the porous materials were characterized by XRD, SEM, XPS and UV-Vis, and the porosity and photothermal properties were tested. The results of characterization and porosity show that the main phases of the porous materials are composed of anatase TiO₂ CaTiO₃, C and Ca₃Mg(SiO₄)₂, the boundaries between the phases are clear. During the calcination process, part of Ti⁴⁺ on the crystal surface of TiO₂ was reduced to Ti³⁺ and oxygen vacancies were formed, which confirmed that TiO₂ was transformed into Black TiO₂.The porosity of the porous material with a starch ratio of 21.74% is 30.5% and has the smallest band gap. The results of photothermal performance test showed that with the increase of starch ratio, the water evaporation rate and evaporation efficiency of porous materials increased significantly at first and then decreased slightly; When the mass ratio of TiO₂, graphite powder, polyvinyl alcohol solution and steel slag is fixed at 1∶1∶1∶4, and the starch ratio is 18.52%, the water evaporation rate and photothermal conversion efficiency of the porous material can reach 1.47kg·m^-2·h^-1 and 69.18%.

Abstract:Aluminum electrolysis technology with inert anode is an important technology for the sustainable low-carbon development of the future aluminum industry and forachieving the strategic goal of carbon neutrality. Inert anode material is one of the core forachieving inert anode aluminum electrolysistechnology.In recent years, domestic and foreign scholars have conducted extensive research on inert anode materials for aluminum electrolysis and made significant progress.The latest research progress of metal alloy, NiFe₂O₄ based cermet anodes, and inert anode aluminum electrolysis technology were focused on in this article. The optimization methods and research status of NiFe₂O₄ based cermet materials were discussed from three aspects: sintering and preparation process optimization, ceramic phase optimization, and metal phase optimization. The conductive and corrosion mechanisms of NiFe₂O₄ based cermet anodeswere also elucidated. Finally, important conclusions that can be clarified from the current research were summarized, and it was believed that aluminum electrolysis technology using vertical electrode structures and metal ceramic inert anodes is the main direction for future industrialization. The main problem that needs to be solved in research and development is to improve the corrosion resistance of inert anodes while balancing mechanical properties (thermal shock resistance) and conductivity. Ceramic phase optimization will focus onenhancing the corrosion resistance and conductivity of metal ceramics. The optimization goal of metal phases is to improve the thermal shock resistance of metal ceramics and form a dynamic and dense corrosion-resistant film layer during the electrolysis process in conjunction with ceramic phases.

Abstract:In recent years, the electrodeposition technology of aluminum and aluminum alloy coatings prepared by electrodeposition in ionic liquids has attracted much attention as a new green process, and aluminum and aluminum alloy coatings have been widely used in aerospace, electronics, automobiles and many other fields.Ionic liquid as an electrolyte has the advantages of high conductivity, wide electrochemical window, etc. Electrodeposition of aluminum and aluminum alloy coatings by ionic liquid can effectively improve the corrosion resistance, strength and hardness of the coatings, which provides a feasible method for strengthening some materials with low corrosion resistance and poor mechanical properties.In this paper, the research progress of electrodeposition of aluminum and aluminum alloys in different ionic liquid systems in recent years is systematically reviewed.The present situation and advantages of different types of ionic liquid electrodeposition of aluminum and its alloys are introduced.The shortcomings and improvement measures are analyzed and summarized.AlCl3 ionic liquid has some defects, such as low stability and complex synthesis process, which limit its industrial application；Adding an appropriate amount of additives can make up for the shortcomings of insufficient liquid stability, complex preparation process and expensive preparation raw materials, but there are still problems of high viscosity and high cost.At present, multi-functional ionic liquids are becoming an important research field in chemistry and materials science. With the deepening of research and the development of technology, ionic liquids are expected to play a greater role in future industrial production.

Abstract:In this paper, the defluorination and dechlorination process of zinc-containing dust by side-blown melting was studied. The four-element ZnO-Fe₂O₃-CaO-SiO₂ slag type was calculated using the thermodynamic software FactSage. The impact of melting temperature on the viscosity and fluidity of the side-blown slag was further investigated. The distribution and trend of Zn, Pb, F, Cl, Ag and other key elements in the side-blowing smelting process were obtained through the analysis and detection of key elements in the smelting products. The experimental results demonstrate that under conditions of natural gas injection heating, the iron-silicon ratio (Fe/SiO₂) was 1, the calcium-silicon ratio (CaO/SiO₂) was 0.5, the melting effect of molten slag wasoptimal when the melting temperature exceeded 1400℃. When the melting temperature wasbelow 1400℃, the slag exhibited suboptimal melting properties. The primary phases identified in the slag produced by the side-blowing smelting process were Ca₂ZnSi₂O₇, Fe₃O₄, Zn₂SiO₄ and ZnFe₂O₄, and the primary phases observed in the side-blowingdustwere ZnO, NaCl, KCl and K₂ZnCl₄. After the side-blowing melting process, the fluorine content in the slag was reduced to 0.057%, with a fluorine removal rate in the raw material exceeding 85%. The chlorine content in the slag was reduced to 0.0091%, and the removal rate of chlorine in the raw material exceeded 99%. In this paper, the feasibility of side-blowing smelting process for treating zinc-bearing dust was preliminarily verified by using 0.28m² side-blowing furnace expansion test device, which provides a new approach for domestic and foreign enterprises seekingto treat zinc-containing dust in alignment with the strategic goal of double carbon emission reduction.

Abstract:The essence of copper slag pyrometallurgical dilution technology is to add pyrite or carbonaceous reducing agent to high-temperature copper slag, so that the magnetic iron in the slag is reduced to FeO, and copper is gathered in the form of copper matte, and finally copper is separated from the slag phase. As a renewable resource, biomass is the preferred material for carbonaceous reductants. In this study, the iron silicon olivine slag was used as raw material, and the effects of biomass and pulverized coal on the reduction of copper slag were compared by single factor condition experiment. The effects of different smelting conditions such as biomass ratio, calcium oxide ratio, silica ratio, reduction temperature and reduction time on the recovery rate of copper in slag were investigated. The results show that under the optimal experimental conditions of reduction temperature of 1310℃, holding time of 120min, biomass ratio of 1%, calcium oxide ratio of 0.5%, silica ratio of 0.5%, and pyrite ratio of 1%, the copper content in the upper layer of the slag is reduced from 1.49% to 0.42%, which achieves the effect of direct reduction of copper slag by pulverized coal.From the perspective of environmental benefits, biomass is more suitable as a carbonaceous reducing agent for copper slag dilution than pulverized coal.

Abstract:A significant amount of waste is generated during the production of gallium arsenide. The recovery of the galliumbecome one of the critical research topics.This paper ingeniously integrates the advantages of various gallium arsenide waste recovery processes and proposes an innovative leaching-extraction-electroplating process. In this process, using gallium washing hydrochloric acid solution as the leaching solution. Based on a meticulous analysis of the mechanisms of leaching, extraction, and electroplating, comprehensive relevant conditions were thoroughly tested, and the following principal conclusions were obtained. In the low acid condition (pH of 1mol/L) of the washing gallium hydrochloric acid solution, the extraction system potential was controlled by regulating the gradient of temperature rise. The arsenic extraction rate up to 96%, and the gallium extraction rate surpassed 97%under the conditionsoffinal leach temperature 75℃, leach time 4h. Using P204 as the extractant, gallium extraction rate was above 99% with two-stage extraction. Notably, the extractant demonstrated no extraction effect on arsenic,andthe separation efficiency of gallium and arsenic exceeding 99%. The stripping was conducted using 150g/L NaOH as the stripping agent with an O/A ratio of 2/1, and the gallium stripping rate was above 99.9%. By adding 0.15g/L EDTA to the stripping solution, the current efficiency was significantly increased from 41% to 78%.Post-electricity was recycled to using as the stripping solution,the gallium leaching rate remained stable at 97%, the gallium extraction rate was consistently at 99.6%, the stripping rate was stay at 99.9%, and the current efficiency was steadily at 78% after three successive recycling experiments.The gallium recovery rate reaching 96% and there is no toxic gas of hydrogen arsenide produced in this process.

Abstract:To address the low efficiency of gallium extraction, the present study synthesized a gallium-imprinted chitosan resin with good adsorption performance for gallium by using chitosan as the carrier, grafting acrylic functional monomers through cross-linking of glutaraldehyde and combining with ion-imprinting technology, and characterized the functional groups and morphology on the surface of the resin with the help of FT-IR spectroscopy and scanning electron microscopy, studied the adsorption kinetic process of the synthesized resin in simulated dissolution solution by adsorption tests, and investigated the reusability of the synthetic resin. The adsorption kinetic process of the synthetic resin in the simulated dissolution solution, the effects of solution pH and competing ions on the adsorption performance of the resin, and the reusability of the synthetic resin were investigated by adsorption tests.The results showed that the surface of the gallium-imprinted resin formed a rough and porous structure; the adsorption of gallium by the resin conformed to the quasi-secondary kinetic model and the Langmuir adsorption isothermal model, and the adsorption process was a monomolecular layer adsorption mainly controlled by chemical adsorption, with the saturated adsorption capacity of 16.28mg·g^-1; the optimal use of this resin was in the pH range of 5~7; the adsorption selectivity of gallium for vanadium and aluminum was higher than that of gallium for the simulated dissolution solution. The optimal pH range of the resin was 5~7; the selectivity coefficients of gallium relative to vanadium and aluminum were 12.50 and 9.87, respectively, which showed better gallium adsorption performance; the adsorption capacity of the resin remained at 80% of the original capacity after repeating the adsorption and desorption cycles for seven times, which had a good reuse effe.

Abstract:In view of the complicated calcium removal process, high energy consumption and high cost in the current sulfuric manganese solution purification, this paper explores the method of removing calcium ions from the solution using P204 extraction. Based on the determined aqueous phase pH value, the study examines the effects of P204 saponification rate, reaction temperature, mixing time, P204 volume concentration, and extraction grade on the Ca concentration in the aqueous phase, and concludes the following main conclusions. The actual extraction reaction endpoint pH value is lower than the optimal pH value by 2.5 to 3.0, and the pH value needs to be maintained above the optimal value during the extraction process by adjusting the saponification rate of the organic phase. The optimal extraction process parameters are P204 saponification rate of 10%, system temperature of 35℃ or above, mixing time of 4 minutes or more, P204 volumetric concentration of 20%, and extraction grade of more than 41, under which the Ca content in the aqueous phase meets the requirement of HG/T 4823—2015 Battery Grade Sulfuric Manganese (i.e., ω_Ca≤0.01%, ω_Mn∶ω_Ca≥3200), and the method avoids the introduction of fluoride ions and eliminates the interference of fluoride ions on subsequent processes. At the same time, it greatly reduces the use of acid and alkali, achieving low-cost purification of sulfuric manganese solution, and has great promotion value.

Abstract:B impurity is difficult to remove during the preparation of solar grade silicon, and alloy-slag composite refining has a good effect on B removal. However, because the slag system contains oxides, the refining temperature needs to be controlled above 1500℃, and the energy consumption is high. In this study, sodium fluoroaluminate was used as a slag material. Using the low melting point and good fluidity of sodium fluoroaluminate, metallurgical grade silicon and copper were combined to achieve high-efficiency composite refining and B removal at low temperature by alloy slagging method. The content change and occurrence state of impurity B in copper-silicon alloy-cryolite molten salt system under different cooling rates, water quenching temperatures and slag-to-metal ratios were investigated. The experimental results show that in the range of 3~0.05℃/min, the lower the cooling rate is, the larger the equilibrium distribution coefficient of B is, and the stronger the ability of boron to segregate from the alloy phase to the cryolite phase is, which is more conducive to the removal of boron impurities. In the range of eutectic point (810℃) to liquid point (910℃), the lower the water quenching temperature, the greater the B equilibrium distribution coefficient, and the better the B removal effect. In the range of slag-to-metal ratio from 1∶2 to 10∶1, the higher the slag-to-metal ratio, the greater the equilibrium distribution coefficient of B. The slag phase of samples contains B compound, indicating that B impurity is segregated from alloy to slag phase, and B impurity can be effectively removed by compound refining at low temperature.

Abstract:Copper matte, also known as matte, mainly composed of Cu2S and FeS, can trap gold, palladium, platinum and other precious metals in refined ore, of which the determination of gold, palladium, platinum and so on is of great significance, the current industry standard lacks the determination method of palladium and platinum in copper matte. In this paper, based on the composition analysis of copper matte samples, the enrichment parameters of copper matte samples were optimized for high copper content and high sulfur content (copper matte sample weighing 10g, anhydrous sodium carbonate content 20g, slag silicate content 0.75, lead oxide content 200g, potassium nitrate content 10g). By adding 30mg pure silver as a protective agent, the loss of gold, palladium, platinum and other precious metals in copper matte can be effectively avoided. Anhydrous sodium sulfate is innovatively used as a covering agent, and the content of gold, palladium and platinum in noble metal composite solution is simultaneously determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). The results showed that the relative standard deviations (RSD, n=11) of gold, palladium and platinum were 0.46%~3.66%, 0.68%~4.68% and 3.19%~4.87%, respectively. The recoveries of metal were 97.9%~105.6%. The method established in this research has high accuracy and operability without obvious matrix effect and spectral line interference, and can meet the quality control requirements of gold, palladium and platinum in copper matte production and the daily analysis and testing requirements of third-party testing institutions.

Abstract:Iron-molybdenum catalyst materials are widely used in the chemical industry field, and have different catalytic properties and catalytic effects in different catalytic reactions because of different molybdenum contents. So the accurate analysis of molybdenum content has a guiding role in the production of iron molybdenum catalyst. At present, the determination and analysis of molybdenum content in national standards and industry standards are mainly molybdenum iron (molybdenum content 50%-75%) and molybdenum concentrate (molybdenum≥40%), while the molybdenum content in iron molybdenum catalyst is usually between 20%-50%, and contains other elements. The sample pretreatment method is different from the national standards and industry standards, and it is necessary to establish new analysis parameters to meet the production needs. In this study, the effects of sample dissolution conditions, precipitation formation parameters and calcination temperature on the determination results were investigated, and the condition parameters were optimized. The optimum conditions were determined as follows : the sample was dissolved by four acid (HCl+HNO₃+HF+HClO₄) , the dropping speed of lead acetate precipitant was 3~5 drops/s, the precipitation aging time was 45min, the aging temperature was 70℃, the precipitation washing times was 15 times, and the precipitation burning temperature was 550℃. Under these conditions, the content of molybdenum in iron-molybdenum catalyst can be effectively analyzed. The relative standard deviation is below 0.20%, and the recovery rate of the sample is 98.0%-101.4%, which can meet the requirements of molybdenum content determination in iron-molybdenum catalyst. However, due to the interference of tungsten on the measurement of molybdenum content, this test method is not suitable for iron-molybdenum catalyst samples containing tungsten.

Abstract:Nonferrous metallurgy wastewater contains a large amount of heavy metals, non-degradable organic matter, and NH+4-N. Biological treatment technologies have garnered widespread attention due to their low cost and sustainability. This review elucidates the performance characteristics of different types of biological technologies based on bibliometric analysis and looks forward to its future development. The bibliometric analysis confirms that the use of biological technologies for treating wastewater is a mainstream technique for the future; however, there is still a lack of in-depth mechanism research. The domesticated membrane bio-reactor focuses on removing nitrogen and organic matter from heavy metal wastewater, while biological filters and sequencing batch reactors are more suitable for simultaneously removing various pollutants. Process improvements and coupling can effectively address wastewater containing multiple heavy metals. The use of microbial agents is cleaner and more sustainable, capable of tackling high-concentration wastewater with coexisting heavy metals and achieving recovery of nonferrous through mineralization. However, measures need to be taken to fix the agents during application, examining the competitive and synergistic relationships between strains to identify optimal parameters. Microbial electrochemical technology, plant-microbe coupling technology, and microbial-algal symbiotic technology are newly developed wastewater treatment technologies in recent years. These three can be coupled to form an efficient integrated wastewater treatment system. In the future, constructing a multi-technology integration system and a circular economy technology system will be important areas of focus.

Abstract:Steelmaking dust is one of the solid wastes produced in metallurgical industry, and it has a higher Zn content. The separation and recovery of Zn from steelmaking dust is of great significance to green and low-carbon development of metallurgical industry. Zn mainly exists in the form of ZnFe₂O₄ in steelmaking dust. In order to separate Zn and Fe, CaO modification was adopted to convert ZnFe₂O₄ into ZnO, and then selective leaching was used to extract the Zn element by using dilute hydrochloric acid. The effects of CaO modification, pH value, temperature, and solid-liquid ratio on the dissolution of Zn and other elements from steelmaking dust were investigated. CaO modification could effectively convert the ZnFe₂O₄ into Ca₂Fe₂O₅ and ZnO, which is easily soluble in acidic solution, resulting in a higher dissolution ratio of Zn and making Fe difficult to dissolve; as the pH decreased, the leaching ratios of the main elements from the modified dust increased; increasing the temperature and reducing the solid-liquid ratio are beneficial for the leaching of Zn, and increasing temperature will inhibit the leaching of Si. Under the conditions of pH=3, temperature 50℃, solid-liquid ratio 1∶25, the leaching ratio of Zn was 72.73%, while that of Fe was not leached, achieving selective leaching of Zn. After leaching, electrolytic deposition can be used to recover metal Zn from the leachate. The leaching residue is mainly composed of Ca₂Fe₂O₅, and can be reused as a metallurgical flux.