China Nonferrous Metallurgy

Abstract:Copper is an important basic raw material for the development of national economy. With the expansion of the copper industry, copper smelting has developed rapidly. At the same time, the industry is also faced with many problems such as raw material safety, environmental pollution and energy utilization, which restricts the development of copper smelting industry. Combined with the historical background of “double carbon” “double circulation” “green development”, this paper comprehensively analyzes the current green development trend of copper smelting industry, and the technical difficulties in the aspects of resources, energy, waste treatment and digital transformation. On the basis of full analysis, the implementation path of the future green development of copper smelting industry is studied, and the development path of productization of valuable elements, energy saving and carbon reduction, cross-border integration, intelligent smelting and construction of copper smelting ecological chain is put forward, and specific implementation suggestions for green development of copper smelting industry are put forward.

Abstract:The antimony and mercury minerals contained in the antimony mercury coexisting ore cannot be obtained through mineral processing to obtain independent mercury concentrate or single antimony concentrate. However, in the case of mixed flotation, the sulfide minerals of antimony and mercury can enter the antimony-mercury composite concentrate with high recovery rate. The thermodynamics of separating antimony and mercury from antimony-mercury composite concentrate by volatilization roasting and the process conditions of selective oxidation volatilization roasting were studied. The results show that the heating-up is beneficial to the reaction, the main products are Sb₂S₃ and Hg0, and the roasting temperature should be less than 1323K；the saturated vapor pressure of various substances in antimony-mercury composite concentrate is different, and the volatilization order is Hg→HgS→Sb₂O₃→Sb₂S₃→Sb；the oxidation order of Sb₂S₃ is Sb₂S₃→Sb→Sb₂O₃→Sb₂O₄→Sb₂O₅; high temperature, high oxygen potential and low sulfur potential are beneficial to the oxidation of antimony, the optimal process conditions for selective oxidation volatilization roasting are as follows: the roasting temperature is 1273K, roasting time is 30mins, material layer thickness is 9cm, blast volume is 15L·min^-1, under these conditions, the volatilization rate of antimony is more than 96.87%, and the recovery rate of antimony oxide powder is more than 96%, volatilizaion rate of mercury is greater than 99.99%, and recovery rate of mercury is more than 98%. The study provides preliminary feasible experimental conditions for industrial production of antimony mercury separation.

Abstract:The electrowinning experiment of silver electrolytic waste liquor was carried out by using cyclone electrowinning equipment，the electrowinning conditions of two kinds of typical silver ion concentration waste liquid A (silver ion concentration 15.42g/L) and B (silver ion concentration 47.42g/L) were studied. The results showed that the silver powder of IC-Ag 99.99 standard could be produced by using 500A/m² for 40min and 250A/m² for 20min in waste liquid A，the direct yield of qualified silver powder reached 79.2%; the silver powder of IC-Ag 99.99 standard could be produced by using 750A/m2 for 90min, 500A/m² for 40min and 250A/m² for 40min in waste liquid B，the direct yield of qualified silver powder reached 72.7%，the impurity copper and palladium in the process of electrowinning of silver electrolytic waste liquor began to precipitate largely with the decrease of silver; with the electrowinning process copper, palladium and other silver electrolyte needed to be purified impurities continue to produce，the aim of impurity removal of electrolyte was realized，the electrowinning liquid could return to the silver electrolysis system to continue to use，the zero discharge of waste liquid in silver electrolysis process was realized simultaneously，the method overcame the problem that nitrate was difficult to be treated in silver electrolysis waste liquor.

Abstract:In recent years, the sources of zinc concentrate in the Northwest Lead Zinc Smelter have been complex and variable, with high residual sulfur and ferrous content in the calcine, more manganese ore powder needs to be added to reduce ferrous ion, resulting in an increase in the manganese ion content of the system and an increase in the unit consumption of electrolytic current. Based on this, a combined oxidation technology of manganese dioxide and hydrogen peroxide was proposed for iron removal, and a single factor conditional test method was used to investigate the effects of solution pH, leaching temperature, and combination of oxidant manganese ore powder and H₂O₂ in different proportions on the oxidation rate of precipitated alum supernatant solution. The results showed that the optimal conditions were as follows: the pH value of the solution endpoint was controlled between 4.8 and 5.2, the leaching temperature was 60 to 70℃, the amount of manganese ore powder added to the oxidation tank was 0.6 times the theoretical amount, the amount of oxidant H₂O₂ added was 1.0 to 1.3 times the theoretical amount, and the oxidation rate was optimal. The oxidation rate of Fe²⁺ was 92%, and the measured manganese ion in the solution was 5-6g/L. In production, the manganese content is maintained at 3-6g/L, and the direct current consumption per ton of zinc can be maintained below 3000kwh. Calculated based on an annual production of 220000 tons of cathode zinc, economic gain of 1.949 million yuan can be generated. The successful application of this technology has played a positive role in improving the indicators of zinc hydrometallurgy.

Abstract:The raw material zinc concentrate used in a new zinc smelter in Xinjiang has the characteristics of high silicon content and low other impurities. Because the high silicon ore will produce sintering in the roasting furnace and ring formation in the rotary kiln in the pyrometallurgical system of zinc smelting, the solid and liquid is difficult to separate after leaching in the wet system, and the above situation will seriously affect the normal operation of the production system. Based on this, the existing form, metallurgical behavior and impact on various zinc smelting systems of silicon were analyzed and studied, and the influence of silicon on different stages of zinc smelting (roasting, acid making, leaching, rotary kiln) and control measures is investigated. The results show by controlling the roasting temperature of 880±20℃, the ratio of silicon to calcium of rotary kiln material is 4∶1, the pH value of acid leaching end point is 0.5~1.5, and using the intermediate leaching and acid leaching supernatant to dilute the corresponding reaction solution 1 time, the combined fire and wet process for treating high silicon and low impurity zinc concentrate is established, which can ensure the normal and stable operation of smelting system and will produce good economic benefits.

Abstract:Thallium and its compounds are highly toxic. There are environmental pollution risks in the production process of zinc hydrometallurgy process.However, the existence of thallium in the intermediate materials of zinc hydrometallurgy process is complex, and the content is low and unstable, which makes it difficult to track, monitor and detect thallium in the intermediate materials of zinc hydrometallurgy process. In this paper, iron salt and potassium bromide extraction were used to eliminate the interference of thallium determination by complex matrix components. The [TlBr₄]_- complex anions formed by Tl³⁺ and Br^- were quantitatively extracted by methyl isobutylmethone (MIBK). Finally, thallium in the organic phase was determined. By optimizing the instrument measurement conditions, the graphite furnace ash temperature was 400℃, the atomic temperature was 1650℃, thus realizing the accurate determination of thallium content in the intermediate materials of zinc smelting process. The detection limit of the method was 0.27μg/L, RSD＜10%, and the added standard recovery rate was 95.2%~102.6%. The method was verified by the national standard material, and the results were accurate and reliable.

Abstract:At present, cyanidation is still the dominant method of gold extraction around the world. The cyanide tailings slurry produced after cyanide leaching of gold containing materials is separated by solid-liquid separation to form gold cyanide residue, and the gold cyanide residues with high toxicity and high harmfulness seriously endanger environmental safety and health, and restrict the healthy development of gold metallurgy industry. Therefore, how to use and dispose gold cyanide residues in a green and environmentally friendly manner is the research focus and hot spot of gold industry. In this paper, the cyanide removal technologies of gold cyanide residue slurry were reviewed, the features and the practical industrial application of each technology were introduced in detail. The examples of comprehensive cyanide removal treatments in the gold industry were summarized, and the future development trend of cyanide removal technology of gold cyanide residue slurry in the future industry was discussed and prospected.

Abstract:A new process combining carbon leaching, acidification stripping, neutralization, sulfur dioxide (smelting flue gas) air method, and XJD heavy metal removal was studied using cyanide tailings from a certain smelter as raw materials. A harmless treatment and comprehensive resource recovery system for cyanide tailings was established to achieve harmless treatment and comprehensive utilization of resources.The results showed the optimum process parameters were as follows:pulp concentration 30%, carbon leaching for 2h, acidification with nitric acid-sulfuric acid mixture, pH=1.5~2.0, acidizing and aeration for 30min, after acid stripping, adding alkali for neutralization,controlling neutralization pH at 8.5,reacting with sulfur dioxide in air for 30min;the process had been applied industrially for two years, which had got good effect, the process of cyanide tailing conformed to the standard Technical Specification for Pollution Control of Cyanide Leaching Residue in Gold Industry（HJ 943—2018）, met the exemption conditions for cyanide tailing in the National Hazardous Waste List (2021 Edition), and the harmless post-disposal process is treated as general solid waste.The process is applied for comprehensively recycling cyanide and precious metal from cyanide tailing, with certain economic and social benefits.

Abstract:The output of secondary aluminum ash in China is large, and the total aluminum content is not low. In the process of stacking, it is leached by rain, resulting in pollution of water and soil salinization. On the basis of previous studies, the secondary aluminum ash produced in the recycled aluminum industry was used as the main raw material, and the effect of silica content on the properties of magnesium-aluminum spinel materials sintered from secondary aluminum ash was studied by solid-phase sintering method, and the sintered products were analyzed by means of XRD, SEM and infrared spectroscopy. The results show that when the mass fraction ratio of secondary alumina ash to magnesium oxide is 1∶0.2, the secondary alumina ash can be sintered into MgAl₂O₄ spinel materials at 1400℃ and held for 3h. Silicon dioxide has an effect on the properties of MgAl₂O₄ spinel materials prepared by secondary alumina ash sintering. When 5% silicon dioxide was added, the performance of MgAl₂O₄ spinel was the best, that is, the bulk density was 2.03g/cm³, the linear change rate was 0.42 and the compressive strength was 91.1MPa. When 5%-20% silicon dioxide samples were sintered at 1400℃, the main phase of the material was MgAl₂O₄ With the increase of silica content, the intensity of MgAl₂O₄ diffraction peak decreased, thicker fibrous structure appeared in the sintered body, and the density of the material increased. The presence of appropriate silica can promote the preparation of high-performance magnesia alumina spinel materials by secondary aluminum-lime sintering. In the sintering process, both the cell constant and the cell volume of the product go through the process of first increasing and then decreasing, which is also the process of ion dissolution in and out. In this study, the secondary aluminum ash can be treated economically and efficiently, which not only reduces environmental pollution, but also solves the shortage problem of resource containing aluminum, which has a certain significance for realization of secondary aluminum ash utilization problem.

Abstract:Phosphorus is one of the main limiting factors for eutrophication in water bodies, and the removal of phosphorus from the aqueous environment is of great significance for the management of eutrophication in water bodies. In this paper, LDHs have large specific surface area, good regeneration ability, and superior anion adsorption properties, making them excellent adsorption materials. A new type of Zn/Co-LDHs nano adsorption material was successfully prepared using zinc nitrate and cobalt nitrate as raw materials using hydrothermal method. The new adsorption material was characterized using SEM, XRD, IR and BET, and adsorption experiments were conducted on phosphorus-containing wastewater. The effects of material dosage, phosphate ion concentration and adsorption time on the adsorption effect were investigated.The results show that the Zn/Co-LDHs nanomaterials have a typical hydrotalcite-like structure and a large specific surface area; the adsorption isotherm of Zn/Co-LDHs on phosphate conforms to the Langmuir and Freundlich adsorption isotherms; the adsorption kinetic process follows pseudo-first-order kinetic model. Under the condition of 25℃, with the 1.0g/L dosage of Zn/Co-LDHs, the 10mg/L concentration of phosphate ions, the adsorption reached the adsorption equilibrium after 30min, and the maximum adsorption capacity was 6.3mg/g. Zn/Co-LDHs had excellent phosphorus removal effect on different types of eutrophic water bodies.

Abstract:Indigenous microorganisms is used for controlling pollution of U(VI) and Zn(II) in uranium tailings wastewater in situ due to their advantages of diverse species, strong adaptability and co-metabolism. The effect of the selected and domesticated indigenous microbial flora on removal of low-concentration uranium and zinc was studied. The effects of bacterial liquid dosage, temperature, pH, U(VI) and Zn(Ⅱ) initial concentration on the removal of uranium and zinc from indigenous microbial flora were investigated. The results showed that for the neutral mixed solution containing 1mg/L U(VI) and 10mg/L Zn(II), the bacterial flora of indigenous microorganisms (Acinetobacter 44.69%, Acetobacter 31.48%, Aureus spp. 13.81%) at a temperature of 35℃ and a dosage of 10% the bacterial solution, the removal effect of two heavy metal elements is the best, the removal rate of uranium and zinc can reach more than 94%, and the reaction is rapid, basically reaching balance in 60min. The characterization analysis of microorganisms showed that a certain amount of sheet-like substances appeared around the cells after the colony reacted with metal ions, and the newly emerged U peak and Zn peak accounted for 6.6% and 0.62% of the cell proportion, respectively. The study provides a certain technical support for treatment of uranium and heavy metals in uranium tailings pond wastewater.

Abstract:Non-ferrous smelting enterprises produce a large amount of arsenic-containing wastewater. Arsenic has a special affinity for the mercapto group of enzyme proteins in the human body, especially with the mercapto group of pyruvate oxidase, causing harm to human body. Copper arsenite can be used as agricultural pesticides, herbicides, antifungals and rodenticides, and can be used as poisons in bullet baits and a raw material for preparation of arsenic trioxide. The copper sulfate precipitation method was used to remove arsenic from wastewater, and the effects of copper sulfate dosage, reaction temperature, reaction time, stirring speed and solution pH on removal of arsenic from arsenic-containing wastewater were investigated. The results show that the dosage of copper sulfate is n（Cu)/n（As)=2.0, the stirring speed is 50r/min, the reaction is carried out at 20℃ for 2.0h, the pH of the solution is adjusted to 8.0, and the yield of copper arsenite is 97.23%, to provide important data support for treatment of arsenic-containing wastewater in non-ferrous smelting enterprises.

Abstract:Steel slag is the main by-product produced in the process of steel making. Comprehensive utilization of steel slag is beneficial to energy saving and pollution reduction. In this paper, with converter steel slag as the main aggregate, supplemented with cement and other cementing materials, by changing the aggregate ratio, the preparation of ecological permeable brick is realized. XRF, XRD, SEM and other analysis methods were used to analyze the composition, phase and morphology of steel slag permeable brick. The main phases of steel slag were Ca₂SiO₄, Ca₃Mg(SiO₄)₂ and Ca₂Fe₂O₅, and the elements in the steel slag composition were evenly distributed and the performance was stable. The effects of steel slag content and ratio of aggregate to cement on the properties of water permeability, compressive strength and flexural strength were investigated. The results show that when the coarse and fine aggregate mixture ratio is adopted, the steel slag content is 80%, and the ratio of aggregate to cement is 6.6, the steel slag permeable brick has high strength and good permeable performance, and the finished product conforms to the standard requirements of Permeable Pavement Brick and Permeable Pavement Board (GB/T 25993—2010).

Abstract:Feldspar, quartz, and calcite are representative gangue minerals in gold concentrates. During cyanide leaching, gold will partially adsorb onto the surface of the gangue minerals, resulting in gold loss. In this paper, the adsorption of gold on the surface of gangue under cyanidation conditions and its adsorption mechanism were studied. The results showed that the highest gold adsorption rate was achieved when the gangue dosage was added at 15g and the contact time was 20min, and the gold adsorption rates of feldspar, quartz and calcite were 14.80%, 3.70% and 2.48%, respectively. The experimental results were fitted using quasi-first order dynamics, quasi-second order dynamics, double constant model and Elovich model. The results showed that the adsorption of gold on the surfaces of the three gangue minerals all fitted the quasi-secondary kinetic model and the double constant model (R²＞0.96), indicating that the adsorption process was dominated by chemisorption and was more likely to occur. X-ray photoelectron spectroscopy (XPS) analysis showed that ≡Si—O^- on the surface of the gangue was the main gold adsorption site.

Abstract:In order to improve the traditional carbothermal reduction preparation of boron carbide for direct high temperature (1800~2000℃), severe dehydration cause boric acid raw material volatilized and low product purity and poor crystal defects. In this paper, with boric acid and petroleum coke as raw materials, the raw material forms (pellets and powder), dehydration temperature, heating time and heating rate on the slow-release effects of dehydration process were studied, the optimum parameters of slow release dehydration were determined and the kinetics of slow-release dehydration was studied. The results showed that the optimal slow release dehydration parameters were as follows: pressing into pellets of raw material, dehydration temperature of 300℃, dehydration time of 40min, and heating rate of 5℃/min.In addition, XRD and chemical composition analysis showed that the purity of B4C was increased by 9.01% and the free carbon content was reduced by 7.95% after slow release dehydration.It can be concluded that the slow release dehydration of raw materials is conducive to maintaining the balance of raw material proportion, so as to improve the reaction degree of carbothermal reduction.

Abstract:Sodium hexafluoroferrate can be used as a cathode material for lithium-ion batteries and sodium-ion batteries due to its strong storage capacity of lithium ions and sodium ions, with such shortages as long technological process, toxic harmful or low-solubility raw materials, poor electrochemical properties. Therefore, a novel method using Na₃Fe(C₂O4)₃ as an intermediate is proposed to synthesize sodium hexafluoroferrate material. The results show that the material prepared at 700℃ for 7h in N₂ atmosphere exhibits excellent electrochemical properties, with the second discharge specific capacity of 229.1mAh/g and the capacity retention of 97.9% after 100 cycles for lithium-ion batteries, the first discharge specific capacity of 138mAh/g and the capacity retention of 90% after 100 cycles for sodium-ion batteries. This route is fairly suitable for industrial production owing to its environmental friendliness, short technological process, low production cost and good product performance.

Abstract:Ultra-high nickel layered material LiNi_0.92Co_0.04Mn_0.04O₂ (Abbr. NCM92) has become one of the important cathode sources for lithium-ion batteries due to its high energy density and price advantages. However, a key challenge for commercial applications is rapid capacity fading and severe structural degradation, especially at high cut-off voltages, resulting from interface instability and irreversible phase transitions. In this study, a ZrO₂/Li₂ZrO₃ double coating modified ultra-high nickel single crystal cathode material was designed, and the surface of the material was uniformly doped with Zr element, which significantly enhanced the high cut-off voltages performance and structural stability of the cathode electrode through the synergic strategy of double coating. The results show that the ZrO₂/Li₂ZrO₃ double coating can effectively alleviate the irreversibility of H2-H3 phase transition of the ultra-high nickel cathode material, improve the mechanical stability and interface stability. At the same time, the TM layer and Li site of the surface Zr doping into the crystal structure inhibit the Li/Ni mixing and widen the lattice spacing. As expected, ZrO₂/Li₂ZrO₃ double-coated with Zr-doped modified materials (NCM92-Zr) demonstrated excellent electrochemical properties at 0.5 C (200mA·g^-1) current densities, after 150 cycles in the voltage range of 2.75~4.4V, the discharge specific capacity of 155.2mAh·g^-1 remains, and the capacity retention is 75.5%. The study provides new insights into the complex mechanisms and improved structural stability of ultra-high nickel cathode at high cut-off voltages.

Abstract:Multivalent metal ion batteries are expected to become an alternative to lithium ion batteries due to their good safety and low cost. In recent years, some encouraging results have been achieved in the research of such batteries, but the development of cathode materials still faces some practical difficulties. This paper summarized the research progress of intercalated cathodes for multivalent metal batteries in recent years, introduced intercalation mechanism of cathode materials and cathode materials such as oxides (vanadium and manganese oxides and their derivatives), sulfides, polyanionic polymers, and carbon materials. Through analysis and summary, it is concluded that there are problems with slow solvation process and solid-state diffusion in multivalent metal ion systems; the research on the application of intercalated cathode materials provides a direction for the design of electrode materials for future such batteries; and transition metal (Mn, V) oxides, sulfides, and other cathode materials to some extent weakens electrostatic forces and improves dynamics. The future development direction of intercalated cathodes for multivalent metal batteries are forwarded.