Sustainable Mining and Metallurgy

Abstract:The solid waste containing zinc such as blast furnace ash and electric furnace steelmaking dust produced by iron and steel plant was seriously polluted, and the treatment was difficult. Based on the introduction of zinc-containing ash output and its main components in iron and steel plants in China, this paper reviewed the current utilization technology of zinc-containing solid waste resources, and analyzed in detail the principle, process flow and existing problems of rotary kiln process, rotary hearth furnace process and wet process in pyro metallurgical reduction. The processes were compared from the aspects of raw material composition, main equipment and facilities, product situation, investment and environmental protection governance，and the development trend of utilization technology of zinc-containing solid waste resources in the future was suggested.

Abstract:Since the epidemic, more and more attention had been paid to the standardized management of medical waste. At present, incineration and high temperature steam treatment were widely used as terminal disposal methods for medical waste in China. The medical waste after harmless disposal had high recycling value. There were some problems in the management of medical waste in China, such as insufficient attention to the harmfulness of medical waste, imperfect management system of medical waste in hospitals, lack of scientific resource utilization of medical waste, and unclear division of labor among supervision departments. By analyzing the necessity of medical waste recycling, the feasibility of medical waste utilization was expounded from the perspectives of policy, market, technology and supervision.

Abstract:By introducing the characteristics of 1 system aluminum alloy and the characteristics of the melting and casting process, it can be seen that the aluminum foil had high requirements for the hydrogen content and inclusion content of the 1-series aluminum alloy melt, and the contents of Ti、Fe and Si in the aluminum alloy and the relative contents of Fe and Si had great influences on the quality of final aluminum foil.In order to produce high quality aluminum alloy slab and cast-rolling plate for 1 series foil，the control of melting-casting process of 1 system aluminum alloy was discussed briefly from the aspects of raw material quality control，chemical composition control，melting process control，on-line treatment process and casting process.

Abstract:Starting from the preparation technology of hydrogen, the advantages and disadvantages of hydrogen preparation technologies such as methanol to hydrogen, coal to hydrogen, natural gas to hydrogen, and water electrolysis to hydrogen were analyzed, and the process of hydrogen consumption in polysilicon production process was analyzed. According to the actual data of existing plants, the hydrogen production and consumption in the process of polysilicon production were analyzed. The optimization suggestions were put forward for hydrogen system from the aspects of the shutdown pressure relief of hydrogenation system，the start and stop of reduction furnace and the public auxiliary system leakage，so as to effectively reduce the production cost of polysilicon.

Abstract:A copper smelting enterprise used a double lower tower oxygen-enriched cryogenic air separation process with one lower tower and one auxiliary tower to prepare oxygen with a concentration of 85%. This paper analyzed the process, compared it with pressure swing adsorption process and conventional pure oxygen air separation process, and put forward optimization measures for the problems existing in the operation of the process. Through the process comparison, it can be seen that there was no problem of pressure swing adsorption production declining year by year in the oxygen-enriched cryogenic air separation process. Compared with the conventional pure oxygen air separation process, it can save energy by 15%~20%. It had the advantages of high oxygen recovery rate, low investment cost and energy consumption, simple operation and maintenance, and stable operation. After continuous optimization, it would show greater advantages.

Abstract:By analyzing the influence of fuel type, air surplus coefficient, combustion temperature in furnace and boiler load rate on NO_x content in flue gas of reduction furnace and fuming furnace, this paper focused on the feasibility practice of reducing NO_x content in exhaust gas and generating economic benefits by controlling excess air coefficient and combustion temperature in furnace during slag release stage. The results showed that the NO_x content in flue gas decreased significantly and the effect of energy saving and emission reduction was obvious by implementing measures of reducing air, gas and carbon in slag discharge period. The oxygen consumption and fuel consumption of reduction furnace decreased month by month and tended to be stable. The motor of fuming furnace can save about 11250kWh of electricity per month, and the amount of denitration agent was greatly reduced, so the production cost was greatly reduced.

Abstract:After years of operation, the heating tubes of five PS converter boilers in a smelter often leak, which seriously affect the normal operation of the converter. By analyzing the process conditions, water quality control and equipment management of PS converter boiler, the causes of heat pipe leakage were found, and specific solutions and measures were suggested, such as restoring the functions of key parts of the boiler, improving water quality management and strengthening operation management, so as to provide reference for the maintenance, emergency treatment and professional management of PS converter boiler.

Abstract:The super-large bottom blowing furnace in a smelter had been running for five years. Through the statistics of brick erosion in each part of the furnace body during overhaul, the optimization measures such as controlling oxygen lance pressure, furnace temperature, slag type and matte grade were put forward. In addition, the operation of the converter was prone to accidents, and there were problems such as deterioration of the field environment, excessive exhaust gas, coking and shedding stuck to the membrane wall, and blockage of the oxygen gun. It was proposed that the safety inspection of the furnace body should be carried out before the converter operation of the bottom blowing furnace, and the pressure of the oxygen gun should be adjusted in time with the change of the rotation angle of the furnace. Furthermore，the copper jacket of outlet of the furnace and the membrane wall were optimized and reformed, so as to eliminate the abnormal situation in the process of the converter.

Abstract:Aiming at the design and application of mixer-settler in a project with an annual output of 10000 tons of cobalt, CFD numerical simulation was used to analyze the water oil distribution, velocity flow field, mixture dispersion zone, residence time and clarification effect in the mixer-settler, so as to provide theoretical support and verification for the optimization design of the mixer-settler. The simulation results were consistent with the PIV experimental results, which showed that the upper layer of the mixer-settler was laminar flow, and the vortex was easy to form at the bottom near the inlet. Based on the simulation model, the internal structure of the mixer-settler was studied. The results showed that adding a grid plate at the inlet of the mixer-settler can make the mixture form a shunt and enter the mixer-settler at a more uniform speed along the whole vertical plane of the inlet, but it would lead to the deterioration of the clarification and separation effect. In addition, the influences of the depth and aspect ratio of the mixer-settler on the two-phase separation were also studied. When the depth of the clarifier reached 1m, the influences of increasing the depth of the mixer-settler on the clarification rate and effect was limited ; the separation effect of the mixer-settler with small aspect ratio was not good, and it was easy to form a dead zone. The above factors should be taken into account in the design of mixer-settler.

Abstract:Combined with the production characteristics of arsenic trioxide in a smelter, a new automatic packaging palletizing system was developed. The system consisted of bag-making packaging machine, conveying roller system, automatic stacking system, and control system. By introducing the composition, working principle of each component system, and the application effect，the system had the characteristics of accurate weighing, no dust in the packaging process, fast stacking speed and neat stacking type, and realized the integrated packaging mode of plastic inner packaging and iron drum outer packaging, as well as on-site unattended and remote production control, which greatly improved the production environment of toxic and harmful solid materials，and improved the production efficiency, so it was worthy of popularization and application in the same industry.

Abstract:Due to a large number of metal structures and electromechanical equipment in the plant area，the electromagnetic environment was complex, so the application effect of LPWAN was difficult to judge. This paper studied the ideal deployment mode of LPWAN nodes, and carried out communication test in a representative complex electromagnetic environment，and analyzed the data transmission of LoRa in short distance, medium distance and long distance of NB-IoT. The practical application and test results showed that the main factors affecting the packet loss of LPWAN communication were the shielding property of metal structure and the electromagnetic interference of electromechanical equipment, rather than the communication distance. In order to the apply LPWAN in the plant area with complex electromagnetic environment, measures such as polling reception and dispatch and antenna extension cord suit shielding net should be adopted. In addition, the LPWAN terminal of the sending end should be arranged as tall as possible to achieve reception and dispatch visual, so as to reduce electromagnetic interference.

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Abstract:The ionic liquid cyclic absorption desulfurization technology had the advantages of high desulfurization efficiency, no secondary pollution, no solid residue, recycling sulfur dioxide. A nonferrous metals company in Guangxi adopted this technology to dispose of low concentration sulfur dioxide flue gas. This paper mainly introduced the process principle，process flow，the calculation and selection of main equipment parameters of ionic liquid cyclic absorption desulfurization technology. Using these equipments, after more than a year of operation, SO₂ emissions can be reduced by 5407.5t per year, and sulfuric acid can be recovered by 8432.32t per year, indicating that the ionic liquid cyclic absorption desulfurization technology had high economic and environmental benefits.

Abstract:Combined with a practical valley-type tailings dam project, under the premise of meeting the existing policies，two feasible dam construction schemes of centerline embankment method and upstream embankment method were comprehensively compared and analyzed from the aspects of reservoir capacity, service life, economy, safety, environmental impact and operation management, and the results showed that the centerline embankment method was better. The analysis method used can provide ideas for similar projects.

Abstract:By analyzing the difference between the continued-built tailings reservoir and the newly-built tailings reservoir, it was expounded that the transition from the old tailings reservoir to the continued-built tailings reservoir should be paid attention to in the construction of the continued-built tailings reservoir, including the construction planning of the continued-built tailings reservoir, the transition scheme of the tailings disposal scale, the transition scheme of the water consumption in the plant, the utilization of the existing tailings facilities and the operation experience of the tailings facilities. Taking the continued-built tailings reservoir project of a copper mine as an example, it was showed how to solve the above problems in practical work according to the actual situation.