Sustainable Mining and Metallurgy

Abstract:To improve the recycling efficiency of new energy vehicle power batteries and address the issues of uneven cost-sharing and low recycling rates,this paper constructed a tripartite game model involving new energy vehicle manufacturers, power battery suppliers, and third-party recyclers, focusing on cost-sharing mechanisms. It analyzed three cost-sharing scenarios: third-party recyclers bearing the recycling costs alone ( Scenario N),manufacturers sharing the recycling costs ( Scenario M),and suppliers sharing the recycling costs (Scenario S). The study also explored the impact of key parameters on the decision-making of the game participants. The research findings indicate that: ① Within a certain range, increasing the cost-sharing ratio can significantly enhance the recycling rate and optimize the overall profit of the supply chain; ② Recycling losses negatively affect power battery recycling,reducing recycling efficiency and profits; ③ From the perspectives of economic and environmental benefits,the supplier costsharing scenario (Scenario S) demonstrates significant advantages. This paper provides a theoretical basis for formulating recycling strategies for new energy vehicle power batteries and offers references for related policy design.

Abstract:With the continuous exploitation of global mineral resources, a large number of mines have been abandoned due to resource depletion or economic reasons, resulting in land abandonment, ecological damage and environmental pollution. However, the current mine ecological restoration work is faced with multiple practical difficulties, such as lagging restoration concept, sticking to the “end treatment” model, single technical means, low integration, heavy construction and light maintenance in management mode, weak supervision system and weak supervision system, which are difficult to meet the needs of modern ecological restoration. This paper took the whole process management cycle of “design-construction-monitoring-maintenance” as the main line of research, systematically discussed the reconstruction of mine repair management mode driven by digital technology, and verified the effectiveness of Internet of Things, Big Data, Artificial Intelligence and other technical means in the whole process of mine repair through practical cases such as Zhalainuoer in Inner Mongolia and Hebei intelligent monitoring platform. This model provides a scientific and accurate solution for mine ecological restoration, which has significant practical value and industry promotion potential.

Abstract:Mine ecological restoration is an important part of ecological civilization construction. Through in-depth analysis of three typical practical cases, this study revealed the prominent problems existing in the ecological restoration of historical legacy mines in Yunnan province, including insufficiently targeted restoration design measures, lack of scientific basis for design, and incomplete follow-up management mechanisms. In response to these issues, this paper proposed the following improvement suggestions: at the conceptual level, deepen ecological thinking, achieve the transformation from traditional “engineering thinking” to “ecological thinking”, and introduce the theory of nature-based solutions to guide restoration design; at the management level, clarify the responsible entity after restoration, explore the mechanism for converting ecological value, and improve the design basis system; at the technical level, it is suggested to optimize the technical standard system, strengthen the whole-process management, and promote the continuous improvement and dynamic update of ecological restoration work. The implementation of these suggestions provides strong technical support and institutional guarantee for improving the quality of mine ecological restoration and promoting ecological civilization construction.

Abstract:Most of the high concentration tailings slurry show the characteristics of Bingham body, and most of them belong to the composite flow state. This paper introduced the calculation method suitable for the critical flow rate and friction loss of large proportion and high concentration tailings slurry transportation. On this basis, the critical velocity and friction loss were calculated for an iron ore tailings slurry transportation case with a tailings density of 3. 1 t / m ³ , transportation concentration of 56% , transportation distance of 8 500 m, and transportation height difference of 470 m. The critical velocity of the pipeline under normal conditions is 2. 656 m / s, and the friction loss is 0. 038 5 mH₂O/ m. After calculation, the steel-rubber composite pipe with an outer diameter of 377 mm and an inner diameter of 329 mm was selected, and four diaphragm pumps with a flow rate of 320 m ³ / h and a lift of 15 MPa were used for the conveying pumps. The transportation of tailings slurry shows that the hydraulic elevation line of pipeline operation is less than the maximum allowable hydraulic elevation line; the outlet pressure of the diaphragm pump is less than the rated pressure of the diaphragm pump. The research in this paper can provide reference for similar high-concentration high-lift tailings pipeline transportation projects.

Abstract:Regarding the changes in slag and liquid iron composition during the direct current furnace treatment of vanadium titanium magnetite, Based on the analysis of raw material properties, theoretical calculations, basic experiments, and DC furnace expansion experiments were conducted to investigate the changes in slag and metal composition during the melting reduction process of vanadium titanium magnetite. Fe mainly exists in Fe3O4 in vanadium titanium magnetite, V and Ti mainly exist in titanium magnetite. Theoretical calculations show that adding lime is beneficial for reduce the melting temperature of the final slag, and increasing temperature is more conducive to reducing the viscosity of the slag. The basic experimental results show that an increase in temperature is beneficial for improving the metal recovery rate. The appropriate ratio of lime and reducing agent has a significant impact on the slag gold separation effect. Under the conditions of temperature 1 580 ℃ , C / O ratio of 1. 0, and lime ratio of 3. 3% , the Fe and V contents in the tailings can be reduced to 1. 20% and 0. 27% ; The results of the expanded test of the DC furnace show that when the iron content in the slag decreases to 14. 38% ~ 16. 21% , the vanadium content is the highest. The Fe and V content in the final slag are 1. 89% and 0. 39% , respectively. The calculated Fe and V recovery rates are 98. 14% and 85. 7% , respectively.

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Abstract:The purpose of this paper is to explore the feasibility and treatment effect of the process of wet pretreatment and rotary hearth furnace collaborative treatment of sintering ash. Through the analysis of the physical and chemical properties of sintering machine head ash, the process flow of washing-rotary hearth furnace collaborative treatment was designed. The effectiveness of “wet pretreatment process” to remove harmful elements and rotary hearth furnace treatment was analyzed, and its influence on the original washing system and rotary hearth furnace system was studied. The results show that the average content of Cl, K2O, Na2O and water in the iron-rich material after washing treatment is 1. 80% , 0. 75% , 0. 7% and 18. 55% , respectively. The average removal rates of Cl, K and Na are 93. 13% , 96. 02% and 83. 10% , respectively, which basically eliminates the negative effect of high chlorine load on the rotary hearth furnace. The main products and operation data of the washing workshop and rotary hearth furnace are not affected compared with the previous ones, and meet the requirements of various standards. The “water washing pretreatment + rotary hearth furnace process” synergistic treatment of sintering ash process is a feasible method, which has good treatment effect and environmental protection benefits.

Abstract:The spent ternary lithium batteries are recovered by pretreatment and hydrometallurgy process. The iron impurity content in the regenerated electrode material generally accounts for more than 2% , which will affect the physical and electrochemical characteristics of the regenerative material. This paper reviewed the research status of iron removal process in the recycling pretreatment and wet leaching stage of spent ternary lithium batteries, mainly including magnetic separation method in the pretreatment stage, precipitation method, solvent extraction method and ion exchange method in the leaching stage. At the same time, the research on iron removal process in the recycling process of spent ternary lithium batteries was prospected. The development direction of green environmental protection aims to provide some new ideas for lithium battery recycling and impurity removal technology.

Abstract:High-purity metals are the key materials for manufacturing various of sputtering targets. The types and contents of impurities in high purity metals affect the performance of down stream products. Electron beam melting and refining(EBMR) is an effective method for metal purification. The principle, equipment and main process parameters of the technology were briefly described in this paper. The application of EBMR technology in the purification of copper, tantalum, titanium and other metals was introduced. Finally, the development tendency of EBMR technology and equipment in the future was prospected.

Abstract:In order to obtain the internal flow, the axial cyclone dust collector of an iron and steel enterprise was taken as the research object. The finite element analysis software STAR-CCM + was used to establish the analysis model of axial cyclone dust collector, and the numerical simulation analysis was carried out based on the discrete phase model theory. According to the internal velocity and pressure distribution of the axial cyclone dust collector, the velocity of the gas is increased after passing through the swirl plate, and the spiral downward movement is generated. During the descent process, there will be two eddy currents at the inlet of the exhaust pipe and the lower cone, which will affect the gas flow. The pressure distribution is mainly divided into three areas: First, the mixing chamber between the swirl plate and the intake pipe. Due to the resistance of the swirl plate, the pressure increases slightly after the gas enters the mixing chamber; second, inside the dust collector, the gas pressure is reduced by the action of the swirl plate; the third is the low pressure area in the exhaust pipe. The dust removal efficiency is 83. 2% , which is close to the actual dust removal efficiency. Through the analysis of the gas-solid flow characteristics of the axial cyclone dust collector, it provides a theoretical basis for further optimizing the structure size and improving the dust removal efficiency.

Abstract:At present, commercial lithium-ion batteries are limited by the performance bottleneck of cathode materials, and the actual specific capacity is difficult to break through 160 mAh / g, which cannot meet the needs of high energy density batteries in various fields. The development of high-performance cathode materials has become an urgent task in the field of energy materials. In this paper, the lithiumrich manganese-based cathode material xLi ₂MnO₃·(1-x)LiNi _{1 / 3}Co₁ / ₃Mn₁ / ₃O₂ was prepared by modified sol-gel method. By adjusting the heat treatment temperature (600 ℃ , 800 ℃ , 950 ℃ ), holding time (8 h, 9 h, 10 h) and component ratio x value (0. 3,0. 5,0. 7), the regulation mechanism of the preparation process on the crystal structure, microstructure and electrochemical performance of the material was systematically investigated. The experimental results show that when x = 0. 5, the heat treatment temperature is 950 ℃ and the holding time is 10 h, the comprehensive performance of the material is the best: at 0. 1 C rate, the first discharge capacity is 321. 5 mAh / g, the coulombic efficiency is 72. 6% , and the capacity retention rate is 84% after 30 charge-discharge cycles. The optimized process provides technical support for the industrial application of lithium-rich manganese-based materials and is of great significance for promoting the development of high-capacity lithium-ion batteries.

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Abstract:Based on the goal of efficient utilization of biogas from anaerobic fermentation of leachate in domestic waste incineration power plant, the comprehensive advantages of biogas power generation in resource utilization, operation stability and carbon emission reduction were demonstrated by comparing the co-combustion of biogas into furnace and independent power generation path. Through the case of a 1 200 t/ d waste incineration power plant, the biogas production, pretreatment process and power generation system design were discussed, and the energy saving effect and carbon emission reduction benefit of biogas power generation were analyzed. The results show that biogas power generation technology can achieve an average annual greenhouse gas emission reduction of 39 780 t CO2 e. In the absence of government subsidies, the annual power generation income of the project can reach 2. 43 million yuan. Biogas power generation can not only convert organic matter in waste into electrical energy, but also effectively avoid the emission of greenhouse gases such as methane, and has significant economic benefits and social benefit.

Abstract:Hazardous waste incineration ash accounts for 15% ~ 25% of the total amount of incineration into the kiln. It is usually sent to hazardous waste landfill for landfill treatment, which has potential environmental risks. The “zero landfill” of ash is the general trend. A hazardous waste disposal center adopts the process of “rotary kiln incineration + electric furnace high temperature melting + washing” to treat organic hazardous waste. The slag from the kiln tail was directly sent to the electric furnace for melting and disposal. The temperature of the molten pool was controlled by reasonable ingredients. The temperature was 1 350 ~ 1 450 ℃ , and the melting products were treated by water quenching process to generate water quenching slag, washing water and flue gas products. The results of acid leaching and water leaching of water quenched slag show that the leaching index of heavy metals meets the national standard, the vitreous content is 98% , which meets the standard requirement of 85% , and can be used as green building materials. The salts entering the water are mainly chloride and sulfate. The degradation efficiency of dioxins in fly ash reached more than 99% . Ash melting disposal technology is an efficient, green advanced technology, which provides a feasible solution for achieving the goal of “zero landfill” of ash.

Abstract:The legacy site of a gas station in Qinghai Province has been idle for many years after its closure, it is now planned to be developed into public facility land. According to relevant laws, regulations and policy requirements, soil and groundwater pollution investigations should be conducted on the land before its development and utilization. According to the pollution identification,preliminary investigation, detailed investigation and risk assessment results, there is petroleum hydrocarbon (C10-C40 ) pollution in the soil. The cause of the pollution is closely related to the long-term leakage or “running, dripping, and leaking” of oil materials in the underground oil depot. The pollution depth is 2 ~ 9 m, and the soil volume is 8 480. 29 m 3 . This survey and evaluation work can provide a basis for the subsequent risk control or remediation of the gas station plot, and provide effective reference for soil pollution investigation and risk assessment of similar gas station plots.