The effects of excess coefficient of manganese fluoride, pH value of solution, reaction temperature and reaction time on the removal rate of calcium and magnesium from manganese sulfate solution were studied by performing single factor experiment with manganese fluoride as a removal agent. Under the optimum conditions, including an excess coefficient of manganese fluoride of 2.0, pH of 5, reaction temperature of 85 ℃ and reaction time of 80 min, the removal rates of calcium and magnesium can reach 97.06% and 95.48%, respectively. The kinetic study on this basis shows that the precipitation reactions of both calcium and magnesium in manganese sulfate solution conform to the Avrami equation, with apparent activation energies of 48.01 kJ/mol and 53.23 kJ/mol, respectively. The surface reaction is a factor to limit the precipitation rates of calcium and magnesium.

As for the precision rolling process, a thickness prediction model was constructed for precision rolling exit by introducing a time domain convolutional network algorithm. The feature information of time-series data of the precision rolling process was extracted by using this time-domain convolutional network model, and the prediction performance of the precision rolling exit thickness was improved by optimizing the structure and parameters of the model. The simulation results of the actual steel dataset show that the proposed time-domain convolutional network algorithm, compared to traditional methods, has significant advantages in evaluation indicators, such as root mean square error, average absolute percentage error, and coefficient of determination, which can provide critical information for decision of on-site engineers.

Mineral processing tests were carried out for a low-grade copper ore from South America containing 0.027% Mo and 0.45% Cu. After optimization of the reagent regime, a close-circuit test by adopting a flowsheet of Cu-Mo bulk flotation plus Cu/Mo separation resulted in a copper concentrate grading 26.93% Cu at 81.96% recovery, and a molybdenum concentrate grading 25.32% Mo at 76.24% recovery. Therewith, copper and molybdenum resources in the lean ore can be effectively recovered.

In order to study the effects of pores in surface-coated carbon layer on the rate performance of graphite cathode materials, a small amount of boric acid was added to generate gasification and effusion effect of boric acid during the softening stage of the coated asphalt. Then, a carbon layer with certain pores was formed on the surface of natural graphite tailings through carbonization, and graphite cathode materials with various proportions of pores were obtained. The results show that boric acid forms a carbon layer on the surface of particles containing mesoporous and macroporous pores. A higher proportion of mesopores in the surface carbon layer leads to more diffusion channels for Li⁺ in the carbon layer L_C, and lower diffusion impedance of Li⁺. In that case, the rate performance and cycling performance of the material are enhanced.

The effects of the amount of NaFeS₂, which was used as an additive, on solid-state reduction and magnetic separation for enrichment of nickel and cobalt, and also the reduction behavior of nickel laterite ore were studied. The results show that with the increase of NaFeS₂ addition, the softening and melting temperature of nickel laterite ore decreases correspondingly during the reduction process; while particles of the Ni-Co-Fe alloy obtained by reduction increase accordingly. The enrichment and recovery effects of nickel and cobalt will be better by adding 10% NaFeS₂. The nickel laterite ore, after being pressed into briquettes, was subjected to reduction at 1 100 ℃ for 60 min, followed by a process of grinding and magnetic separation, resulting in a high quality nickel-cobalt-iron powder grading 7.89% Ni, 0.66% Co and 74.01% Fe, at corresponding recoveries of 97.13%, 86.78% and 35.81%.

The stability of slope with fault under the impact of blast-induced seismic wave was analyzed by using simulation to study the dynamic response of slope with different fault thickness under the impact of explosive vibration. The results show that there exists elevation amplification effect when blast-induced seismic wave propagates along slope surface and fault area. The thicker the fault, the faster the attenuation of blast-induced seismic wave. As the fault becomes thicker, the displacement of slope under the action of blast-induced vibration gradually increases, and the overall deformation resistance becomes smaller. Under the action of blast vibration, the fault with different thickness obviously brings different influence to slope stability. With the fault thickness of 2-8 m, the slope stability decreases continuously and rapidly, and tends to be stable as the fault thickness exceeds 8 m.

The crystal structure and surface properties of minerals and the mechanism of interaction between minerals and flotation agents were systematically analyzed by means of quantum chemical calculation and molecular dynamics simulation. Meanwhile, the flotation mechanism of kyanite minerals and quartz was discussed. The results show that the differences in the surface properties of kyanite, andalusite, sillimanite and quartz determine the differences in floatability, and citric acid can increase the floatability difference between kyanite minerals and quartz. The simulation result of computational chemistry is consistent with the experimental result of flotation.

Based on an established three-dimensional analytical model for arching stress of cemented backfill, a calculation formula for vertical load of cemented backfill was obtained. According to a model of four-sided fixed roof and a criterion for ultimate tensile strength of rock mass, a method to determine the thickness of horizontal pillar for safe extraction was obtained. The application practice of horizontal pillar extraction in 612 stope of a lead-zinc mine shows that the vertical stress of cemented backfill calculated with this analytical model is basically consistent with the numerical simulation results, and no plastic zone occurs in the roof in numerical simulation, which verifies that the reserved roof thickness determined by calculation meets the requirement of safe production. The results of stoping process show that the maximum cumulative displacement near the monitoring point is lower than the displacement limit, and the reserved roof tends to be stable. It is concluded that the determined thickness of horizontal pillar is reliable for safe extraction.

Based on the experimental study on fragmentation and pulverization characteristics of polymetallic nodules in the process of ore lifting, it is found that there is obvious fragmentation of nodules during lifting process. With the volume concentration of 6.5%, the mass percent of polymetallic nodules with particle size larger than 50 mm decreases from 75.58% to 23.78%; with the volume concentration of 15%, the mass percent decreases from 51.51% to 10.08%. Pulverization of nodules was observed in the experiment. With the volume concentration of 6.5%, the mass percent of the polymetallic nodules powder with particle size less than 0.1 mm is 1.79%, and the median particle size is 10.07 μm; with the volume concentration of 15%, the mass percent of polymetallic nodule powder with particle size less than 0.1 mm is 1.99%, and the median particle size of the powder is 9.47 μm. Based on the experimental data, it is estimated that as per mining of 10 million tons of polymetallic nodules, the powder discharge will cause tens of thousands of tons of Fe and Mn losses, as well as hundreds of tons of Co, Ni and Cu losses. Besides, the maximum redeposition thickness of the sediment plume induced by mining is more than 3 mm after diffusion and settlement, which will bring a significant impact to environment.

In order to process copper complex wastewater from electroplating industry, a kind of kaolin was modified by using a modifier of 3-mercaptopropyl trimethoxysilane (MPTS) to be as an adsorbent, and its adsorption of E330-Cu was then studied. It is found that kaolin shall be properly modified at 50 ℃ for 6 hours with the modifier MPTS at an amount of 0.04 mL/g, which is then adopted as an adsorbent for E330-Cu. After 35 min- adsorption at 35 ℃, with E330-Cu at an initial concentration of 5 mg/L, adsorbent at an amount of 15 g/L, and pH value of 4.5, the final adsorption rate can reach 92.50%. It is shown that the adsorption process follows Langmuir isothermal adsorption model and quasi-second-order kinetic model. This kind of adsorbent can be repeatedly used for at least 3 times, and the wastewater after processing can meet the national classⅠdischarge standard. This research can provide reference for the treatment of copper-containing complex wastewater from electroplating industry.