China Nonferrous Metallurgy

Abstract:Currently, lead-acid batteries face limitations such as low energy density, short cycle life, and large size and weight, which result in their limited application in the domestic energy storage sector. Lead-carbon batteries, which feature a carbon-modified negative electrode, represent an advancement over traditional lead-acid batteries by significantly enhancing cycle life and mitigating failure phenomena. The inherent advantages of lead-carbon batteries, such as low raw material costs, high recyclability, and superior safety, make them ideally suited for large-scale and long-duration energy storage applications. In the context of the sustainable development of the recycled lead industry, leveraging the technological benefits of lead-carbon batteries to expand their production and applications in energy storage is a crucial strategy for optimizing energy load balancing and improving local energy frameworks. Future initiatives will focus on deploying pilot demonstrations of new lead-carbon battery energy storage systems within major wind and photovoltaic bases in deserts and Gobi regions, accompanied by the development of lead smelting facilities and the lead-carbon battery supply chain. This approach aims to establish a comprehensive industry cycle spanning raw material sourcing, smelting, advanced processing, application demand, and recycling.

Abstract:The advancement of clean energy and the implementation of “dual-carbon” goals are reshaping energy structures and upgrading grid systems, precipitating a massive demand for long-duration energy storage, projected to increase five to ten times by 2030 compared to 2025. Vanadium redox flow batteries (VRFBs), known for their safety, longevity, flexibility, and abundance of resources, have seen a surge in development, driven by several policy frameworks aimed at clean energy storage standards. Currently, the high cost of VRFBs, primarily due to the expensive vanadium raw materials, poses a significant challenge. A key cost reduction strategy involves optimizing the extraction of vanadium resources and manufacturing of electrolytes. The short-process technology for preparing vanadium electrolyte, developed by China ENFI, reduces manufacturing costs by 30% to 50% and is characterized by a streamlined process and higher vanadium utilization. With continued advancements in resource extraction and process innovation, the cost-reduction potential of the VRFB industry is set to enhance markedly. Supported by national policies, vanadium flow batteries are poised for rapid commercialization and scalability, positioning them as a vital technology in the energy storage sector. Future development will require a multi-faceted approach, including significant emphasis on technological innovation, research, and an effective recycling system, to ensure the sustainable growth of the long-duration vanadium flow battery energy storage industry.

Abstract:It is of great significance for the smelting of lowgrade and highimpurity complex copper concentrates to explore the distribution characteristics of mpurity elements Pb, Zn, Asin the products during bottomblowing melting process, as well as the relationship between the melting parameters and the distribution pattern of impurity elements. This study adopts the method of combining theoretical analysis of thermodynamic calculation software Factsage and analysis of actual production data to explore the distribution characteristics of Pb, Zn, As in the product and its influence mechanism, and obtains the following main conclusions. Increase the temperature is conducive to the volatilization of Pb, Zn into the dust to reduce its proportion in the slag and matte, and is also conducive to the promotion of As transform from slag intodust, but it will lead to an increase in the proportion of As in the matte; Increasing ofFe/SiO₂ in salg will result in a gradual decrease in the distributionproportion of Pb and Zn in the slag and a gradual increase in the distributionproportioninmatte and slag, while the distributionproportion of As in the slag will increase. The increase of CaO content in the slag will make the distributionproportion of Pb and Zn in the slag decrease and increase in the dust and matte, the distributionproportion of As in the slag will increase and decrease in the dust. In the actual production operation, the smelting temperature can be increased to promote the volatilization of some impurity elements, in the appropriate reduction Fe/SiO₂of slag to improve the removal rate of Pb, Zn at the same time, with the addition of CaO to promote the transformation of As to the slag. Actual production data statistics show that the distribution of Pb in matte, slag, dust accounted for 23.86%, 33.12%, 43.02%, Zn were 4.47%, 88.54%, 6.99%, As were 16.58%, 15.34%, 68.08%.

Abstract:Gold minerals in high arsenic and high sulfur gold concentrate are coated with arsenopyrite (As₂O₃) and pyrite (FeS₂), and the leaching rate of direct cyanide leaching is low. The pretreatment technology of high arsenic and high sulfur gold concentrate has been the focus of research attention. In this paper, Tajikistan gold concentrate with high arsenic and high sulfur is taken as the research object. On the basis of thermogravimetric analysis and thermodynamic analysis, a two-stage roasting method is used for pretreatment to remove most of the harmful impurities such as arsenic, sulfur and organic carbon, and the process parameters are optimized. The effects of additives, calcination temperature and time on the removal rate of carbon, sulfur and arsenic in gold concentrate were investigated. Based on the phase analysis of the final calcination product, the roasting-cyanide leaching test was carried out, and the main conclusions were obtained as follows. The first-stage roasting was carried out in a low oxygen atmosphere without additives, and the optimum process parameters were roasting temperature 500~550℃ and roasting time 2h. The second-stage roasting was performed in an oxygen-rich atmosphere, and the optimum process parameters were roasting temperature 650~700℃ and time 2h. Under the above optimal process parameters, the removal rates of carbon, sulfur and arsenic were 91.16%, 96.93% and 92.52%, respectively, and the gold leaching rate reached 95.30%. Compared with the direct cyanide leaching, the gold leaching rate is increased by 20%, which realizes the high value utilization of resources to a certain extent, and provides a technical basis for efficient gold extraction from refractory gold concentrate.

Abstract:In the actual production process of recovering waste platinum catalysts using the total dissolution method, there are still insoluble deposits, resulting in secondary pollution and waste of platinum group resources. In this study, insoluble particles were crushed and finely ground, and about 300 mesh powders were calcined. The obtained powders were then leached in the HCl-DCEA system to investigate the effects of reaction time, reaction temperature, liquid-solid ratio, hydrochloric acid concentration, and DCEA concentration on platinum leaching rate. Significant factors such as liquid-solid ratio, hydrochloric acid concentration, and DCEA concentration were selected for response surface optimization experiments. The results indicate that the significant order of influence on platinum leaching rate is DCEA concentration＞liquid-solid ratio≈hydrochloric acid concentration; The optimized process conditions are leaching time of 2hours, leaching temperature of 70℃, liquid-solid ratio of 6∶1, hydrochloric acid concentration of 2.35mol/L, and DCEA concentration of 0.09mol/L. Under these conditions, the waste platinum catalyst is recovered and treated, with a total recovery rate of 99.64%.

Abstract:At present, the Ruthner type spray roasting reactor has been widely used in the process of recovering acid washing liquid in iron and steel industry. At present, the demand for solid spherical CeO₂ particles is constantly expanding, which makes the large-scale production of CeO₂ particles with the Ruthner type spray roasting reactor attractive prospect. Since the roasting reaction process is difficult to be characterized by experiment, using ANSYS Fluent simulation software to simulate the roasting reaction process, the process of CeO₂ particles generated by CeCl₃ pyrolysis can be intuitively displayed. In this study, thermogravimetric experiments were performed to verify that the pyrolysis processes of iron chlorides and cerium chlorides were identical, but the temperature was different: CeCl₃ droplet completely lost free water at 200℃, and completely reacted at 500℃. FeCl₂ drops completely lose free water at 180℃, and react completely at 420℃. CeCl₃ droplets completely lose free water at 160℃, and react completely at 410℃, so it is theoretically feasible to produce CeO₂ particles using a reactor that treats acid wash. Further, the distribution of temperature field, velocity field and concentration field in the reactor was explored by using the two-phase flow and component transport models in the simulation software package. The results showed that the higher the temperature in a certain region, the faster the corresponding air flow and particle movement velocity.

Abstract:Lead and zinc oxide slag with high zinc content was synthesized at high temperature using high lead slag as raw material, and anthracite was added as reducing agent for direct reduction experiment. The experiment studied the effects of reducing coal amount, reducing temperature, reducing time, Fe/SiO₂, CaO/SiO₂ on the recovery rates of Pb, Zn, and Cu in lead and zinc oxide slag. The experimental results showed that the recovery rates of Pb, Zn, and Cu of lead and zinc oxide slag increased with the increase of reduction coal amount, reduction temperature, and reduction time. However, excessive coal ratio and reduction temperature are not conducive to the improvement of Pb and Cu recovery rates; The recovery rates of Pb, Zn, and Cu of lead and zinc oxide slag increased with the increase of Fe/SiO₂ and CaO/SiO₂. However, as Fe/SiO₂ increased to 0.78 and CaO/SiO₂ increased to 0.8, continuing to increase Fe/SiO₂ and CaO/SiO₂ would reduce the recovery rates of Pb, Zn, and Cu. The suitable conditions for the reduction of lead and zinc oxide slag were: coal ratio of 1.2~1.4, reduction temperature of 1623~1673K, reduction time of 90~120minutes, Fe/SiO₂=0.78~1.17, CaO/SiO₂=0.5~0.8. Under the above process conditions, the recovery rates of Pb, Zn, and Cu in lead and zinc oxide slag could reach 84.01%, 94.51%, and 85.8%, respectively.

Abstract:The physical field of rare earth electrolyzer is affected by different distribution positions of conductive plates. In order to explore the optimal location of the conductive plate distribution in the rare earth electrolytic cell, in this simulation, an arithmetic series distribution gradient is introduced for the distribution of the conductive plate, the simulation values of physical field in the groove under different distribution gradients are compared, then the optimal distribution model of conductive plates in rare earth electrolytic cell is obtained. During the simulation, it is observed that the sharp angle at the bottom of the cathode has a great influence on the experimental results, on the basis of other conditions remaining unchanged, the bottom of the cathode is optimized from a cylinder to a hemispherical shape, and the rationality of the new electrolytic cell structure is verified by comparing with the unoptimized structure. The simulation results show that as the conductive plate shifts from the side to the middle, the temperature and anode potential in the tank remain unchanged, the potential difference between the cover plate and the anode gradually decreases, and the current density in the tank slowly increases. When the bottom of the cathode molybdenum rod is changed from a cylindrical structure to a spherical structure, the potential distribution in the tank is more uniform, and the current density is also increased compared with the previous structure. The optimized structure can improve the local overheating problem and increase the electrolytic efficiency.

Abstract:The organic matter in sodium aluminate solution poses a significant threat to the production of alumina. Currently, the determination of humic acid concentration in sodium aluminate solution is cumbersome and the accuracy of the measurement results is low. This article innovatively proposes a method based on the humic acid concentration measured by the “extraction precipitation method”, using the “absorbance method” to quickly determine the humic acid concentration, and explores the degradation law of humic acid entering industrial sodium aluminate solution during high-temperature cycling. The main conclusions are as follows. The principle of extraction precipitation method is to add barium salt solution to the reverse extraction solution to precipitate humic acid, then calcine the precipitate, and calculate the humic acid concentration by the mass of the calcined product. The humic acid concentration in the industrial sodium aluminate solution used in the experiment is 1.80g/L; The principle of absorbance measurement is to first determine the absorbance curve equation Y=1.6298X-0.1628 through experiments, and then measure the absorbance of the solution to be tested. The absorbance measurement value should be between 0.2 and 2.0, and the concentration of humic acid in the solution to be tested can be calculated by substituting it into the equation. Temperature and time have a significant impact on the removal of humic acid. The higher the temperature, the longer the insulation time, and the higher the removal rate of humic acid. After insulation at 280℃ for 1h, the removal rate of humic acid is 68.30%; Temperature and time have little effect on the total organic carbon in sodium aluminate solution, as well as the mass concentration of small molecular acids such as malonate, formate, acetate, succinate, and oxalic acid. However, the mass concentration of oxalate increases significantly after prolonged insulation, and industrial production needs to pay attention to the changes in the mass concentration of sodium oxalate.

Abstract:Rapid and accurate detection of silicon and zirconium content in silicon-zirconium alloy is of great significance for production. The silicon content was determined by referring to the industry standard “Method for determination of potassium fluosilicate Content in export ferrosilicon” (SN/T 1014.1—2001)，For silicon-zirconium alloys with high zirconium content, it is difficult to react completely, and the measured results are low. The inductively coupled plasma atomic emission spectrometry is more suitable for the determination of trace or trace zirconium. However, the mass fraction of zirconium in silicon zirconium alloy is greater than 10% and the content range is wide, which is not suitable for this method.In this study, the silicon-zirconium alloy was dissolved with sulfuric acid, nitric acid, hydrochloric acid and hydrofluoric acid, and then the silicon was converted into fluorosilicate, and then the potassium fluorosilicate was precipitated with saturated potassium nitrate solution, and dissolved and precipitated with hot water. The hydrofluoric acid was titrated with sodium hydroxide standard solution, so as to measure the silicon content indirectly. Zircon alloy is dissolved in acid solution, zirconium and amygdalic acid form zirconium amygdalic acid precipitation, filtration, burning into zirconia, weighing, indirect conversion of zirconia content by zirconia content. The relative standard deviation (n=6) of silicon and zirconium content was 0.13%~1.39%, and the standard recovery of accuracy test was 96.20%~104.60%. The results show that the method has good precision and accuracy, and can meet the determination requirements of silicon and zirconium in silicon-zirconium alloy.

Abstract:The standard curves with large gradient in content range are established with standard samples such as vanadium-titanium blast furnace slag, vanadium slag, high-titanium slag, and blast furnace slag. And Al, Si, Fe, Ca, Mg, P, Ti, Mn, K, Na, V and Cr in slag are determined at the same time. The sample was prepared by melting, and the mixed flux of lithium tetraborate and lithium metaborate(67∶33) was used as the melting system. The effects of the selection of melting flux, melting temperature, dilution ratio and the amount of release agent on the melting effect were discussed. The standard curve was corrected by using α coefficient correction of change theory and spectral line overlap correction, and the precision of the method was investigated, among which the relative standard deviation was 0.21%~4.20%(n=10). The analysis results are compared with those of volumetric method and inductively coupled plasma atomic emission spectrometry, and the results are satisfactory, which can be applied to the rapid analysis of various types of vanadium slag samples.

Abstract:As arsenic in the sulfide concentrate is getting higher and higher, the arsenic content in the acidic wastewater produced by the flue gas treatment process is also getting higher and higher, and the acidic wastewater contains valuable metals such as copper and iron. At present, the method of removing arsenic from acidic wastewater is mostly for the purpose of removing arsenic, and the arsenic-containing slag formed belongs to hazardous waste and needs secondary treatment. In this study, a new process of arsenic removal by reduction was developed. Firstly, arsenic sulfide slag was added to the waste acid for copper removal and copper recovery. Then, arsenic in the solution was reduced by aluminum powder to recover arsenic. Finally, potassium sulfate was added to the arsenic removal solution to recover aluminum. After recovering the reducing agent, the final solution was treated by two-stage neutralization method. The following conclusions are obtained through experiments. Under the conditions of adding arsenic sulfide slag with 1.1 times molar amount of copper ion, reaction temperature 85℃ and reaction time 3h, the copper content in the waste acid decreased from 2000mg/L to 196mg/L, and the copper sulfide slag was returned to the smelting batching system. Under the conditions of reduction temperature of 70℃, reduction time of 2h and reducing agent dosage of 1.8 times, the reduction rate of arsenic is more than 96 %, the arsenic content in the reduced solution is less than 300mg/L, and the grade of arsenic slag is more than 95%, which can be used for the subsequent preparation of high-grade elemental arsenic. When the amount of potassium sulfate is 1.1 times, the reaction temperature is room temperature, and the reaction time is 2h, the solution contains 3.6g/L aluminum, and the obtained alum can reach the first-class product standard of ‘industrial aluminum potassium sulfate’ ( HG/T2565—2007 ). This method has good arsenic removal effect, and can convert arsenic in waste acid into arsenic products, and will not produce hydrogen sulfide gas, which has application and promotion value.

Abstract:Beryllium is a kind of toxic metal that will cause significant harm to the human body. Industrial production will produce much beryllium wastewater, resulting in high ecological risk. Based on previous studies, this paper reviewed the advantages and disadvantages of different treatment methods (precipitation, adsorption, ion exchange, solvent extraction, and biological method) on the removal of beryllium from beryllium-containing wastewater in terms of material dosage, pH value required for treatment, treatment selectivity, removal efficiency, removal mechanism, and recovery performance. In order to provide reference for the development of green and efficient beryllium removal methods and comprehensive utilization of beryllium resources. The traditional precipitation method produces secondary pollution when treating beryllium wastewater, and the amount of precipitating agent is significant. Although the adsorption method can recover beryllium, the competitive ions impact the adsorption effect and the high adsorption cost. The development of new adsorption materials and the preparation of cheap adsorbents can improve its industrial application value. The ion exchange method can also recover beryllium, but the process wastewater is challenging to treat, and the resin is easy to oxidize and fail, and the cost is high. The solvent extraction method is mainly used in the extraction stage of mining processing and is unsuitable for treating industrial beryllium wastewater. Biosorbent materials based on biological modification have the advantages of low usage, a wide range of treatments, easy to cause secondary pollution and strong selective adsorption ability. Therefore, research and development of new treatment technology, seeking environmentally friendly, low price, excellent treatment performance of treatment methods, is needed to achieve efficient treatment of beryllium-containing wastewater development trends. The following points may be the focus of research: preparation of adsorbents with high selective adsorption properties for beryllium, such as adsorbents loaded with groups such as carbonate, phosphate, and hydroxyl; Developing biosorbents with high adsorption capacity; Combining the advantages of various treatment methods, a new treatment technology is developed.

Abstract:Rare metals support the economic development and advanced high-tech industries in various countries. China has a large reserve of rare metals and a high grade of raw ore, but its distribution is sparse, the amount of available per capita is small and the extraction rate is relatively low. The consumption of rich mineral resources cannot fully meet the needs of industrial production demands. Therefore, extracting or recovering rare metals from low-grade ore or waste has become a current research hotspot. The accumulation of solid waste seriously affects the acid-base balance of groundwater and topsoil, causes heavy metal pollution and destroys the original stable structure of ecosystem. Research has shown that a large amount of rare metal elements are enriched in solid waste, and the value-added of solid waste can be greatly increased by bioleaching technology. In this paper, the yield, physical and chemical properties, bioleaching mechanism, classification and process of several common solid wastes are introduced, and the research progress of common solid waste bioleaching technologies are summarized. The results show that the current solid waste bioleaching technology still faces many problems, such as low intelligent level, low short-term income, long cycle, and complex process link. There are difficulties and breakthroughs in the selection of new leaching strains, adaptability of microorganisms to solid waste, and specific extraction of single elements. A series of suggestions are put forward, such as closing to new quality productivity, developing intelligent bioleaching technology and optimizing process structure. The comprehensive utilization of solid waste is still in the developing stage. The research and development of resource-saving and environmentally friendly biological leaching technologies is of great significance for the efficient utilization of rare metal resources.

Abstract:The bubbles generated on the anode side wall during the rare earth electrolysis process will affect the stable operation of the electrolytic cell. According to the similarity principle, the low temperature experiment of water electrolysis was designed according to the geometric ratio of 1∶2 to the rare earth electrolytic cell, and the microelectrode was prepared by the method of platinum wire embedded in epoxy resin. The experimental results show that the process of bubble nucleation, growth and detachment on the side wall of vertical microelectrode conforms to the classical formula of bubble growth law. In order to observe the coalescence and detachment behavior between bubbles, three nucleation sites were designed on the surface of the microelectrode. Through high-speed camera shooting, it was found that the two bubbles below and in the middle of the microelectrode surface first coalesced into a bubble, and then attracted the bubbles above to coalesce with it. Finally, the three bubbles merged into a large bubble and detached from the microelectrode. Based on the numerical simulation method, the coalescence process between bubbles is further explained.

Abstract:Aiming at the stable control requirements of production and application based on micro heterogeneous purification technology of molten steel technology, the micro-explosive composite sphere is taken as the research object to carry out experimental and numerical simulation research. Based on the HJC model, the influence of kinetic energy and equivalent strain on the explosive reaction of composite sphere was studied, and the factors affecting the optimal state of the reaction, analysis of multi-point uniform detonation state of the composite sphere layer size and raw material ratios and other factors on the impact of the bursting reaction, to get the following conclusions: When the distribution of CaCO₃ powder is uniform in the process of powder preparation, the uniform initiation can achieve the best effect; The size of the kinetic energy generated when the burst is proportional to the dispersion distance of the mass, the same size and density of the composite sphere, multi-point homogeneous detonation of the kinetic energy is the largest, the dispersion effect is the best, the widest range of coverage; The smaller the thickness of the outer layer of the composite spheres, the better the reaction effect, and the middle layer thickness of 5mm is the furthest away from the reaction products; The ratio of CaCO₃ to CaO is 1∶10, the coverage is the most extensive.

Abstract:Anode carbon residue is a harmful solid waste generated during the aluminum electrolysis process. Enterprises often use the pyrometallurgical process to burn carbon to recover electrolytes from it. The pyrometallurgical process is a commonly used recycling process for the sustainable development of the aluminum industry, but the treatment process has problems such as insufficient combustion, low electrolyte recovery rate, and unclear combustion kinetics. This article uses TG-DSC analysis and dynamic analysis to study the combustion performance and dynamic control conditions of anode carbon slag, analyzes the influence of heating rate on the combustion process, and obtains the following conclusions. The heating rate has a significant impact on the combustion of anode carbon slag. When the heating rate is 30K/min, the ignition temperature and maximum weight loss temperature increase to 525.79℃ and 1085.79℃, respectively. The maximum weight loss rate decreases to 0.22%/℃, the flammability index C decreases, the ignition index Ci increases, and the heat release during ignition increases to 790.38kJ/g. The high electrolyte content of anode carbon slag leads to asynchronous surface and internal temperatures of particles, and the ignition mode is heterogeneous ignition, which is not affected by the heating rate. The calculation results of Coats Redfern integration method show that the combustion fitting results of anode carbon slag at temperatures of 476~886℃ conform to the chemical reaction function model g(α)=(1-α)-^1/2, the limiting step is mainly controlled by chemical reactions. The combustion fitting results at temperatures ranging from 886 to 1100℃ conform to the one-dimensional diffusion integral function model g(α)=α². The restrictive links are mainly controlled by diffusion.