Sustainable Mining and Metallurgy

Abstract:Based on the actual production data of a copper-cobalt mine in Africa, this paper analyzed the carbon emission characteristics of the mine, and made an exploratory prediction of its future emission trend, and finally planned the carbon reduction path according to the prediction results. The analysis results show that carbonate decomposition, oil extraction and combustion of mining vehicles and equipment, product drying, and diesel power generation are the main emission items of the mine. Based on this, the mine can reduce carbon emissions and achieve low-carbon development by increasing the proportion of pre-throwing waste rock, optimizing the process to reduce the water content of products, developing photovoltaic power, and improving the digital level.

Abstract:This paper briefly introduced the desalination technology of saline wastewater in non-ferrous metallurgical industry, analyzed the technical characteristics of various process routes, and took two wastewater treatment projects as examples to quantitatively analyze the carbon emission reduction effect of low-temperature thermal wastewater desalination technology. In a low-salt wastewater treatment project in Shanxi Province, compared with the traditional process of “reverse osmosis membrane concentration + evaporative crystallization”, the low-temperature thermal wastewater desalination technology can reduce carbon emissions by 89. 12% ; in a high-salt wastewater treatment project in Gansu Province, compared with the baseline scenario “softening pretreatment + MVR evaporation crystallization” process, the low- temperature thermal wastewater desalination technology can reduce carbon emissions by 69. 16% . It is believed that under the background of “carbon neutralization” and “carbon peak”, low-temperature thermal wastewater desalination technology can significantly reduce carbon emissions by using low-grade heat as the main heat source, which is an energy-saving, emission-reducing, economical and efficient wastewater desalination technology.

Abstract:In order to evaluate the synergistic performance of pollution reduction and carbon reduction in hydrogen based shaft furnace process, this paper constructed a synergistic performance evaluation system for pollution reduction and carbon reduction in hydrogen based shaft furnace process. The coupling coordination degree model was used to construct the synergistic index among pollutant emission, carbon emission and cost control. The synergistic effect of pollution reduction and carbon reduction in traditional blast furnace converter long process and three hydrogen based shaft furnace processes (hydrogen produced by coke oven gas , hydrogen produced by natural gas, hydrogen produced by green electric) was evaluated. The research shows that the all green electric green hydrogen process has the best performance in reducing pollutant emissions and carbon emissions. In terms of cost, the comprehensive cost of the all green electric green hydrogen process is the highest ; comparing the synergistic index of pollution reduction and carbon reduction of each process, the coordination between pollution reduction, carbon reduction and cost control of hydrogen based shaft furnace process is stronger than that of long process blast furnace converter process. Among them, the synergistic indexes of pollution reduction and carbon reduction of coke oven gas hydrogen production process and natural gas hydrogen production process are 0.843 and 0.722, respectively, which reach the level of good coordinated development and intermediate coordinated development. Due to the high cost of the all green electric green hydrogen process, the synergistic effect of pollution reduction and carbon reduction is second, and the synergistic index of pollution reduction and carbon reduction is only 0.463, which is on the verge of imbalance and recession. If the electricity price cost and discount rate can be reduced, the overall coordination effect will also increase.

Abstract:The restoration of soil characteristics around mining induced ground fissures is an important content and key to realize ecological restoration and soil and water conservation in coal mining subsidence areas in the middle reaches of the Yellow River. Taking the soil in the mining induced ground fissure development area of the coal base in northern Shaanxi as the research object, through field sampling, indoor soil culture test, comparative analysis and other methods, the remediation effect of adding exogenous biochar on the physical, chemical and microbial properties of the soil in the mining induced ground fissure development area was studied and revealed. The results show that the addition of exogenous biochar could repair the physical, chemical and microbial properties of the soil around the mining ground fissures, and the improvement of soil microbial properties is the most significant, with the maximum improvement of 84% compared with that before repair. The addition of exogenous biochar has the most obvious repair effect on the physical, chemical and microbial properties of the soil at a horizontal distance of 20cm on both sides of the mining ground fissure. The addition of 3% exogenous biochar is the best addition amount to repair and improve the physical, chemical and microbial properties of the soil in the mining induced ground fissure development area.

Abstract:The construction of green mines is a powerful grasp in the construction of ecological civilization in the mining field and an important measure to promote the high quality development of the mining industry. Support policies are conducive to giving play to the subjective initiative of mining enterprises and are an important driving force for the comprehensive construction of green mines. This paper comprehensively summarized the specific practices of local implementation of support policies for green mines. On the whole, support policies show three major characteristics of combination of resource supply policies and fiscal, tax and financial policies, combination of incentive policies and restraint policies, and combination of direct policies and indirect policies. Five typical experiences were systematically summarized, in terms of resource priority allocation, fiscal fund awards and exemptions, multi tax co governance preferences, financing capacity improvement, and joint credit punishment. However, it still faced challenges such as the inadequate laws and regulations, incomplete policy systems, and the insufficient departmental coordination. Finally, policy optimization paths were proposed from three aspects: improving laws and regulations, increasing policy efforts, and strengthening departmental coordination.

Abstract:The mining process of ionic rare earth mines has undergone many improvements. The combination of magnesium sulfate leaching, magnesium oxide enrichment and sodium salt precipitation can better meet the needs of the market, but the effect of sodium ions on soil and vegetation is still unclear. According to the sodium sulfate concentration used in the actual mining of the mine, this paper took typical plants and soil as the research object, and simulated the influence of sodium sulfate concentration on plants and soil in the leaching process through seed germination, planting experiment and soil column experiment. The results of seed germination and planting experiments show that when the concentration of sodium sulfate is not higher than 0.5%, the seed germination rate, bud length, root length and biomass of typical plants, as well as the number of plants, plant height, leaf fresh weight and dry weight of plants, are less affected and within an acceptable range. The results of soil column experiments show that sodium sulfate has little effect on soil pH at the experimental concentration. The content of SSC and sodium ions increase significantly with the increase of sodium sulfate concentration, and the content of SSC and sodium ions decrease significantly after washing with clear water, and the washing effect is obvious. The results of soil ESP and EC are lower than the critical value of sodium soil, and decrease significantly after washing with clear water. The above results show that the entry of sodium ions into the mountain will have a certain impact on the soil environment. After the mining is completed, clean water leaching can effectively reduce its impact on the soil environment.

Abstract:After years of mining, a large number of historical abandoned mines have been formed in the original asbestos mine in Sichuan Province, which has a serious impact on the surrounding ecosystem and human settlements safety. This paper analyzed the complex geographical conditions of abandoned asbestos mines and the ecological restoration problems, and put forward the practical path of “planning guidance systematic prevention and control quality and efficiency improvement value transformation”, carried out “prevention and control restoration” systematic governance, and formulates “zoning, classification and time sharing” system control for dangerous solid waste asbestos tailings to create a demonstration of special mineral restoration. After remediation, through band building such as “ecological +”, “cultural tourism +”, “giant panda +” to achieve multi channel empowerment and promote the transformation of its ecological value. By breaking through the traditional mine single restoration mode, it is expected to provide new solutions to the difficulties and bottlenecks in the ecological restoration and transformation of abandoned mines with special minerals.

Abstract:Mine ecological restoration is an important part of ecological civilization construction and integrated protection and governance of mountains, rivers, forests, farmlands, lakes, grasslands and deserts in the Three Gorges Reservoir Area in the new period. Based on the systematic analysis of the development status of the mine ecological restoration and the integration of culture and tourism in the Three Gorges Reservoir area, taking Chongqing Fangdoushan area as an example, this paper discussed and sort out the internal advantages and disadvantages, external opportunities and challenges of the mine ecological restoration project and the integration of culture and tourism by using SWOT analysis method. The results show that under the background of Rural Revitalization and global tourism, Chongqing Fangdoushan area has advantages in terms of its unique natural and cultural conditions and industrial synergy potential. At the same time, it faces some disadvantages and challenges, such as the mismatch between ecological restoration requirements and tourist demand, strict control of ecological protection red line, and the evaluation system of ecological restoration to be improved. Based on the research, this paper put forward corresponding countermeasures, aiming to help the local promote the ecological restoration project, stimulate the development of tourism industry, solve the problems of single investment and low economic benefits of ecological restoration projects, and refine the path suggestions for the integrated development of culture and tourism of mine ecological restoration projects, which provides a reference for the comprehensive improvement and value promotion of the mine geological environment in the Three Gorges Reservoir area.

Abstract:Multi time and multi source domestic high resolution series satellite data from 2018 to 2023 were collected to dynamically monitor the development of mineral resources and the changes of mine geological environment in Dalian. According to high resolution remote sensing data, the geological environment problems of mines in Dalian are mainly concentrated in open pit mines. The mining minerals are mainly limestone, granite, building stone and quartzite. The types of land occupation are mainly transit sites, solid waste and boundary mining. The state of the mine is mostly closed and abandoned by policy. From 2018 to 2023, the area of mine occupation and destruction of land resources and topographic landscape in Dalian showed a downward trend as a whole. Mine geological disasters are decreasing, and the area of mine ecological restoration is increasing year by year. The results of high resolution remote sensing monitoring are more objective and accurate. The research can provide an important basis for formulating scientific and reasonable mine environmental protection measures and promoting the sustainable development of mines.

Abstract:To address the frequent short circuit faults caused by the shorting of anode and cathode plates during the copper electrolysis process, which leads to significant energy loss, this study selected the electrolytic cell voltage signal as the object of analysis. By deeply analyzing the changes in the voltage signal of the electrolytic cell before and after the occurrence of short circuits, a short circuit fault diagnosis method combining Local Mean Decomposition (LMD) and Particle Swarm Optimization Extreme Learning Machine (PSO-ELM) was proposed. First, the Local Mean Decomposition (LMD) technique was used to decompose the original signal into several pure amplitude modulation frequency modulation components (PF), and the relative energy and total energy of each component were calculated, with the first three PF components selected as feature values. To overcome the limitation of the Extreme Learning Machine (ELM) requiring a large number of hidden layer nodes, this study employed the Particle Swarm Optimization (PSO) algorithm for parameter optimization. Subsequently, the extracted feature values were input into the optimized PSO-ELM model to achieve identification of short circuit faults. Experimental verification using field collected data showed that the accuracy of the Extreme Learning Machine (ELM) model combined with Local Mean Decomposition (LMD) and Particle Swarm Optimization (PSO) in the diagnosis of short circuit faults in the electrolytic cell can reach 91.09%, an increase of 6.98% compared to the single ELM diagnostic model and with good stability. Therefore, this model has the potential to be applied in industrial production for short circuit fault identification.

Abstract:As an important industrial base in China, the accumulation of bulk industrial solid waste in Panzhihua is becoming more and more serious. Its resource utilization is of great significance to promote the development of low carbon building materials and achieve sustainable goals. This paper systematically reviewed the application status of five typical industrial solid wastes, including tailings, smelting waste, coal gangue, desulfurization gypsum and sludge, in the field of building materials in Panzhihua City, and focused on the analysis of their innovative technical paths and application effects in the fields of concrete, brick and composite cementitious materials. On this basis, this paper further reviewed the main problems existing in the current solid waste recycling process, including technical bottlenecks such as insufficient activity of some materials, high cost of large scale application, and high risk of heavy metal leaching. In view of the above problems, it is proposed that the research on efficient excitation and stabilization technology should be strengthened, the application scenarios and market scale of solid waste should be expanded, the ways of resource utilization should be innovated, and the policy support system should be improved, so as to promote the efficient recycling of industrial solid waste in Panzhihua and provide strong support for the realization of the goal of “ dual carbon ”.

Abstract:A smelter upgraded the traditional Ausmelt oxygen enriched top blown bath smelting furnace and P-S converter into a top side blown composite bath smelting furnace and a multi gun top blown furnace, and cancelled the settlement electric furnace matching the Ausmelt furnace, realizing the transformation and upgrading of the traditional smelting process to the green low carbon short process continuous copper smelting process. This paper systematically expounded the operation of the process system and the main technical and economic indicators, introduced in detail the production operation points of the furnace opening and stopping operation, and summarized the prevention of accidents such as foam slag control, water leakage of water jacket and combustible gas explosion. After the process transformation, the production is continuous and stable, and high grade copper matte and high quality crude copper are stably produced. The copper content of the smelting slag is less than 2%, and the unit cost of anode copper is reduced by about 330 yuan. The process has significant advantages in energy saving and environmental protection, reducing air pollutant emissions and reducing production costs.

Abstract:In this paper, the low copper reduction leaching solution with copper content of 0.52g/L was used as raw material, and iron powder was used to carry out copper and arsenic precipitation experiments. The effects of iron powder coefficient, reaction time, reaction temperature and copper arsenic ratio on copper and arsenic precipitation were investigated. The results show that the addition coefficient of iron powder is the main factor affecting the effect of copper precipitation and arsenic precipitation. The ratio of copper to arsenic has a great influence on the removal of arsenic, and the reaction time and reaction temperature have little effect on the effect of copper precipitation and arsenic precipitation. When the iron powder coefficient reaches 1.8, the reaction temperature is maintained above 70℃, the reaction time is 1h, and the ratio of copper to arsenic is 2.36, the copper deposition rate and arsenic deposition rate are 82.69% and 72.73%, respectively. The copper content in the liquid after copper deposition is 0.09g/L, and the arsenic content is 0.06g/L.

Abstract:The acid leaching solution with high copper content was reduced by iron powder to recover copper. The effects of pH value, temperature, time and iron powder addition on the reduction effect were studied. The SEM-EDS and XRD phase analysis of the generated sponge copper were carried out. The φ pH diagram of Cu-As-Fe-H2O system was drawn by thermodynamic software to study the change of phase in the solution system. The results show that when the reaction temperature is 40℃, the reaction time is about 30min, the amount of iron powder is about 1.1 times of the theoretical amount, and the pH value of the solution is not adjusted, the copper precipitation rate can reach more than 99%, and the content of As and Te impurities in the obtained sponge copper is low. The internal elements of sponge copper are evenly distributed, and its morphology is mainly flocculent. A small amount is similar to the morphology of iron powder, showing irregular polygons. The flocculent is mainly the product of the full reaction of iron powder and copper ions in the leaching solution. The polygonal particles are mainly composed of a small amount of copper, iron, Cu₂O and copper arsenic compounds. Sponge copper is mainly composed of FeCu₄, Cu₂O and Cu₃As.

Abstract:The content of manganese, lead and silver in zinc electrolysis anode slime of zinc smelting system is high, which has high recovery value. The indium extraction waste liquid of the indium recovery system is generally discharged after the sewage treatment process reaches the standard. The heavy metal ions such as iron, manganese and zinc enter the gypsum slag through the sewage treatment process and occupy a large amount of land resources. Based on the reducibility of Fe²⁺ ions, this paper proposed to use Fe²⁺ ions in the indium extraction waste liquid to react with manganese in the anode mud of zinc electrolysis to comprehensively recover manganese, lead and silver in the anode mud, and then used fresh wet copper slag and copper sulfate to dechlorinate, and used aluminum sulfate and calcium hydroxide to defluorinate, comprehensively recycle the indium extraction waste liquid and save the treatment cost of the indium extraction waste liquid. The experimental results show that the recovery rate of manganese can reach more than 98% under the conditions of temperature 80℃, leaching reaction time 3h, anode mud addition amount 0.8 times of the theoretical amount. The wet copper slag and copper sulfate were stirred at 60℃ for 2h to dechlorinate, and the dechlorination rate reached 91.86%. Appropriate amount of aluminum sulfate and calcium hydroxide were added to the dechlorination solution. Under the conditions of filtrate pH 5.2~5.4, temperature 60℃ and reaction time 45min, the defluorination rate reached 93.44%. The dechlorination and dechlorination solution met the process requirements of zinc hydrometallurgy electrolysis process.

Abstract:The lead anode is obtained by the preliminary refining of crude lead by melting and removing copper by pyrometallurgical method. The electrolytic refining is carried out in the silicofluoric acid system to obtain the precipitated lead and the residual electrode. If the bismuth content in the lead electrolyte and the anode slime washing water is too high, the bismuth grade of the precipitated lead will be effected. In this paper, a method was proposed to remove Bi³⁺ by adding a certain amount of substance A (a sulfide) in the process of lead anode mudding, so that most of the Bi³⁺ in the washing water becomes sulfide and precipitates into the anode mud. The experimental results show that the concentration of Bi³⁺ in washing water can be reduced from 200mg/L to 18mg/L under the conditions of liquid solid ratio of 5∶1, slurrying temperature of 40℃, stirring time of 60min and substance A dosage of 0.5g/L, which will not affect the chemical composition of lead electrolyte, and the qualified rate of lead precipitation will be increased from 60% to 100%.

Abstract:Taking a domestic sewage treatment plant in a county in Northwest China as the research object, the emission factor method was used to calculate the carbon emissions, and the main power consumption equipment of the sewage treatment plant was analyzed, and the carbon emission reduction effect of distributed photovoltaic was simulated. The results show that the carbon emissions of the sewage plant mainly include CH₄, N₂O and CO₂ produced by power consumption. In 2021, the proportion of N₂O emissions in the direct carbon emissions of the sewage plant was 49.3%, mainly from nitrogen nitrification and denitrification reactions, and the proportion of CH₄ emissions was 50.7%, mainly from the A2O sewage treatment process. The biochemical pool, the direct carbon emission equivalent of each quarter is different; the carbon emission generated by the power consumption of the equipment is 1697.38t, accounting for 99% of the total indirect carbon emission in the plant area. The total area of the plant that can be used to deploy distributed photovoltaic power generation equipment is 9479.96m². It is calculated that the average daily power generation can reach 6788.88kW·h, accounting for 85.5% of the total daily power consumption in the plant, and the carbon emissions that can be reduced account for 46.31% of the total carbon emissions. According to the calculation of investment cost, distributed photovoltaic can complete cost recovery in only 4.83 years, indicating that the distributed photovoltaic in sewage treatment plants can effectively reduce carbon emissions and has certain economic benefits in the long run.