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This is an essay in the field of metallurgical engineering. Taking a lithium mica ore in Jiangxi as raw material, the roasting-leaching, mixed acid ripening, direct acid leaching and alkali pressure cooking process were explored. Finally, the sulfate roasting-water leaching method was used to extract lithium from lithium mica ore. At the same time, the effects of roasting temperature, roasting time, additive type, additive amount, liquid-solid ratio and leaching temperature on lithium leaching rate were studied. The results show that roasting temperature has a great influence on lithium leaching rate, and the leaching effect of lithium is better in the appropriate roasting temperature range. 40% potassium sulfate, 20% sodium sulfate and 20% calcium oxide were added to the lithium mica ore, calcinated at 900 ℃ for 1 h, and the calcine was leached at room temperature for 1 h according to the liquid-solid ratio of 1∶1. The lithium leaching rate reached 94.87%. This shows that the effect of using sulfate as an additive to roast and extract lithium is better. Through the study of the roasting mechanism, it can be seen that the mineral structure is reconstructed after the addition of sulfate after high temperature roasting. The sodium and potassium ions in the ore are replaced with lithium ions in the lithium mica, so that they are separated from the insoluble aluminum silicate minerals to generate soluble lithium sulfate, which is then immersed in water and then into the solution.

In order to explore the influence of the seepage of the leftover water sump in the open pit on the mining stability of the mine roadway after the coal mine is converted from open pit mining to underground mining, taking Pingzhuang West Open pit Mine in Inner Mongolia as the research background, the two wing water silos and mine workings are modeled by using FLAC numerical simulation software. On this basis, the points for attention and improvement measures in the mining process of the two wing roadway are proposed. The numerical results show that the maximum plastic pressure of the roadway is concentrated at the bottom of the roadway under two working conditions; the displacement deformation plastic zone is not connected, and the tunnel has no overall plastic connection failure and water permeability failure under the influence of seepage; under the condition of extreme water level, the seepage flow at the bottom of both wings of the roadway increases obviously, but the maximum seepage flow meets the specification requirements; due to the time effect, the strength of the surrounding rock of the roadway decreases and long-term creep deformation will occur at the same time. Therefore, waterproof and drainage measures should be taken for the pit bottom and pool.

For the problem of stick-slip vibration caused by hard rock formation in the process of drill bit penetrating in coal mine, and the discrete element method (DEM) was employed to study the rock cutting performance and stick-slip vibration behavior of PDC bit drilling in five typical different hardness rock strata. The result shows that the stick-slip phenomenon of the bit is more obvious with the increasing of the formation hardness, and in the ultra-hard rock layer, it slips on the rock surface and cannot be effectively drilled. The approach of increasing the rotational speed of the bit can weaken the stick-slip behavior to an extent, but it has no obvious effect on improving the drilling efficiency. The drilling performance of the bit can be improved by increasing drilling pressure, but it will also lead to more serious stick-slip vibration. The torsional impact method can effectively weaken or even inhibit the stick-slip vibration of the bit and improve the drilling performance. However, excessive torsional impact force will lead to an increase in the impact load on the bit.

Based on the research background of Shandong Lilou Coal Mine, this paper used methods such as on-site investigation, engineering comparison, and on-site monitoring to research on the high-energy events that have occurred in Lilou Coal Mine since 2020, and drew the following conclusions: ①Systematically analyzed the relationship between four influencing factors and high-energy microseismic events including the distribution of abutment pressure, working face “square”, crossing faults, and mining speed, and searched the causes of large energy events. The mining influence range of No.1302 (top) working face is about 30 m behind the face to 170 m in front, and the advanced stress peak is about 70 m in front. The lateral microseismic events are mainly distributed along the gob-side entry, and the whole is offset to the side of the goaf. The distribution of microseismic events at No.1303 working face in the advancing direction of the working face ranges from 15 m behind the face to 200 m in front of the face, and the advanced stress peak is about 80 m in front of the face. The microseismic event at the No.1303 working face is bimodal in the lateral distribution pattern, shifting to the belt grooves. Affected by the wide coal pillar, the stress concentration on the belt grooves is higher than that on the track tunnel. The frequency and energy of microseismic events gradually increased before the “square” of the work face, and stabilized after the “square”. Before crossing the fault, the microseismic events gradually increased, decreased sharply during the crossing, and gradually stabilized after crossing the fault. The peak position of the event was about 40 m in front of the “square” or before the fault. When the mining speed of 1302 (top) working face is 50 m/month and the 1303 working face is 60 m/month, the frequency and energy are the largest. ②By analyzing the inducing factors and locations of large-energy events, large-energy events can be divided into three categories: “energy accumulation type” high-energy events, “fault activation type” high-energy events, and “island structure type” high-energy events, and put forward specific prevention and control measures for different types. The research in this article will provide reference for surrounding mines with similar geological factors and mining technical conditions.

In order to effectively prevent and control the rock burst in the asymmetric pressure-relief working face under protective layer, taking the 0291 working face of Tangshan Coal Mine as the engineering background, the theoretical analysis and numerical simulation methods were adopted, and the potential influence factors of rock burst in the working face and the occurrence area were analyzed. The results show that the mining depth, bursting tendency of coal seam and its roof, residual pillars in upper protective layer and goaf of the coal seam and thick and hard roof are the potential influence factors of rock burst. Before mining, under the influence of the residual pillars in the protective layer and goaf, the stress of the two tunnels in the 0291 working face shows an asymmetrical distribution. The high stress area of the return airway is mainly located below the cutting line and stop line of the 0250 goaf, while the high stress area of the transportation roadway is mainly located below the cutting line of the 0251 goaf. The working face had obvious zonal characteristics. In the early stage of mining, the advanced stress in surrounding rock of transportation roadway is higher than that of return airway. It is necessary to strengthen the monitoring of transportation roadway and take pressure-relief measures in time. When the working face enters the lower part of 0251 goaf, the surrounding rock stress of the transport roadway decreases rapidly, and the prevention focus should be transferred from the transport roadway to the return air roadway. According to the results of numerical simulation, the impact zones can be divided and the prevention and control measures of impact zones in the mining were put forward. Field monitoring results show that the measures taken can effectively reduce the occurrence of rock burst.

According to the characteristics of cyanine tailings in Xiajiadian gold ore, hydrogen peroxide oxidation method and sodium percarbonate (solid hydrogen peroxide solution) oxidation method were carried out to test and study the effect of cyanogen-breaking tailings, aiming to make the cyanogen-breaking tailings meet the backfilling and utilization requirements of HJ 943-2018 《Technical Specification for The Control of Cyanide Residue pollution in the Gold Industry》. The results showed that the cyanide breaking effect of sodium percarbonate (solid hydrogen peroxide) oxidation method was not as good as that of hydrogen peroxide, but the pH value of cyanogen-containing tailings slurry was adjusted to 9, and 2 g/L hydrogen peroxide was used to break the cyanide for 1 h without adding the catalyst CuSO4. The total cyanide content of tailings could be reduced to less than 0.9 mg/kg, and the leaching toxicity index of tailings could meet the requirements of standard backfill utilization.

The presence of iron and aluminum in the red mud affect the leaching and extraction of scandium and rare earths. Through the analysis and testing of the Bayer process red mud, a technical plan for the reduction and sintering to recover aluminum and iron was designed, and the process of the molten deep reduction and sintering to extract aluminum and iron from the red mud was systematically studied. Under the optimum conditions, the grade of iron concentrate is 73.97%, the recovery rate is 90.27%, and the dissolution rate of aluminum is 96.28%, the aluminosilicate mineral is converted into sodium aluminate, and the sodium aluminate solution is obtained by alkali leaching, which can be used to prepare polyaluminum chloride products in the subsequent. The iron-containing complex minerals in the red mud are transformed into magnetic magnetite and elemental iron, and the iron-containing minerals are recovered by magnetic separation to realize the coordinated recovery of iron and aluminum in the red mud. The process not only weakens the adverse effect of aluminum and iron ore on the subsequent extraction of scandium, titanium and rare earth by acid leaching, but also enriches titanium, scandium and rare earth in the tailings, which is conducive to the realization of multi-element comprehensive utilization of red mud.