In order to investigate the reaction behavior of associated thallium sulfide in zinc concentrate during fluidized roasting, thermodynamic calculation and verification experiments were conducted for the oxidation process of thallium sulfide. Firstly, the volatilization of thallium chloride, thallium oxide, metallic thallium and thallium sulfide were analyzed based on data retrieval and calculation, and the volatilization of those four matters was determined in the following descending order: Tl₂O>TlCl>Tl₂S>Tl. Then, the equilibrium analysis and the calculation of Gibbs free energy change of the Tl₂S-O₂ system were conducted. It is shown that Tl₂S volatilizes violently in an inert atmosphere as temperature rises, and decomposes into Tl and sulfur vapor after temperature is above 1 000 ℃. However, in an oxidizing atmosphere, Tl₂S begins to generate a large quantities of Tl₂SO₄ after the temperature reaches 100 ℃, and a few of Tl₂S begins to decompose into SO₂ and Tl₂O after temperature is above 1 000 ℃. No interaction occurs between Tl₂S and ZnO. In the practical roasting process, Tl₂S is completely converted into Tl₂SO₄ and remains stable in the calcine at the temperature above 800 ℃, which can be intensively removed in the subsequent open-circuit of leaching and purification process.

Based on the optimization of flotation parameters of a low-grade spodumene ore from Sichuan, processing tests were conducted by adopting four flotation schemes to investigate their advantages and disadvantages. It is found that both the process of flotation with full-size range of ores followed by middling regrinding and the process of desliming followed by flotation and sequential returning of middlings are more advantageous than the conventional flowsheet of flotation with full size-range of ores followed by just sequential returning of middlings. It is shown that Li₂O recoveries by two processes can be increased correspondingly by 1.08 and 1.53 percentage points, and the second processing technique can bring a higher Li₂O recovery at 86.7%. However, the first processing technique can produce a higher quality lithium concentrate with a Li₂O grade of 5.76%.

The separation process and the on-site equipment used for processing a copper-molybdenum bulk concentrate in Yunnan are systematically introduced. By improving the technical flowsheet and optimizing configuration, the processing capacity of Cu/Mo separation system can be increased from 25.00 t/h to 35.70 t/h, while the Mo grade and recovery are improved by 3.98 and 5.74 percentage points, respectively. Meanwhile, the power consumption can be reduced by 10.21%, and the unit production cost of Mo metal can be reduced by 7.06%, bringing a good economic benefit.

The influence and reaction mechanism of sodium humate as a depressant on the flotation of apatite, dolomite and calcite in sodium oleate system were investigated by performing single-mineral flotation test, adsorption test, Zeta potential measurement, infrared spectroscopy analysis and X-ray photoelectron spectroscopy analysis. The results show that sodium humate can strongly depress dolomite and calcite at pH of 7, but has less effect on apatite flotation. Sodium humate is weakly adsorbed onto apatite, but it can be adsorbed onto dolomite via chemical bonding, and also adsorbed onto calcite by the combined effect of hydrogen bonding and chemisorption. As a result, the variation in adsorption of sodium humate onto apatite, dolomite and calcite leads to its selective depression of the latter two minerals.

Aiming at addressing the difficulty in selecting parameters for the support vector machine (SVM) model in predicting slope safety factors, a Newton-Raphson Backtracking Optimization (NRBO) algorithm was optimized to assist the SVM model in rapidly selecting appropriate hyperparameters. The NRBO algorithm was improved by introducing a dynamic opposition-based learning strategy, horizontal and vertical crossover strategies, and a modified adaptive coefficient calculation formula, so as to construct an INRBO-SVM model for predicting slope safety factors. Six factors, including bulk density, cohesion, internal friction angle, slope angle, slope height and pore water pressure ratio, were selected as model inputs, with the safety factor as the output. The trained INRBO-SVM model, NRBO-SVM model, SVM model and RBF model were used to predict the safety factors of nine test samples. The results show that the INRBO-SVM model exhibits the best performance in safety factor prediction, with a correlation coefficient of 0.999 9, higher than those of the other models. Its root-mean-square error and mean absolute error are significantly lower than those of the other models. Engineering application results indicate that the prediction errors of the INRBO-SVM model for safety factors are all less than 10%, with most below 5%, confirming the accuracy and practical application value of the model in predicting safety factors.

In order to assess stability of the current multi-level mined-out areas in Qijiaojing iron mine in Subei County Bolun Mining Development Co., Ltd.of Western Mining Limited Company, the mine excavation process was simulated with FLAC^3D software to mainly analyze the stress and displacement changes in the mined-out areas after multi-level excavation. The results indicate that the stress in the mined-out areas is predominantly compressive stress, which is primarily concentrated in the roof and pillars of the stope. The maximum compressive stress, approximately 20 MPa, is observed in the pillars of the mined-out area at the 2 150 m level. It is found that the mind-out area has the maximum settlement of 20.30 mm and the maximum horizontal displacement of 7.22 mm, being satisfactorily stable. However, long-term exposure of large-scale mined-out areas may lead to deformation and collapse of pillars. Therefore, regular inspections and reinforcement measures should be taken for the pillars during subsequent production processes.

As for a gold-bearing pyrite from Hebei Province, the influence of four oxidants, including H₂SO₄, H₂O₂, HNO₃ and KMnO₄, on its floatability was investigated, and the adsorption of collectors on pyrite was also explored by infrared (IR) analysis and electrochemistry measurement. The flotation test shows that with H₂SO₄, H₂O₂ and HNO₃ as oxidants, moderate oxidation can promote the floatability of pyrite, while the oxidation of KMnO₄ can obviously depress the floatability of pyrite. The IR analysis shows that the effects of these four oxidants on pyrite-collector interaction are in the following descending order: HNO₃>KMnO₄>H₂O₂>H₂SO₄. The oxidation of KMnO₄ may passivate pyrite and reduce its floatability. Electrochemical analysis shows that H₂SO₄ and HNO₃ have obvious oxidation effects on pyrite. By increasing oxidant concentration, the double xanthate formed on pyrite due to its reaction with xanthate will be oxidized by H₂O₂ solution, and the hydrophobic layer on pyrite will be destroyed, leading to the decline of pyrite's floatability.

The western No.2 mining area of a certain mine adopts the non-pillar sublevel caving in mining, and excessive wedge cut height in the 1 546 m sublevel leads to poor blasting effect. To address this problem, blasting with wedge cut was specially studied. Firstly, the rock parameters were calibrated based on the RHT constitutive model and the damage threshold of the rock was determined to be 0.4 by a fluid-structure interaction analysis with the LS-DYNA software. A comparative analysis of the cut blasting effects with different cut width shows that with the cut height fixed at 23 m, the effective damage rate of the rock presents a unimodal distribution with an increase in cut width. The optimal cut width is found to be 24 m, with which the effective damage rate of the rock can reach a peak value of 0.692 5. Based on these parameters, the on-site application of designed cutting scheme indicates that over 85% of blast-forming space can meet the requirement, presenting a reasonable fragment distribution of muck pile, with the angle of repose at approximately 40°.

A low-grade manganese carbonate concentrate was processed by adopting direct sulfuric acid leaching. The effects of leaching parameters on the leaching rates of manganese, calcium and magnesium were investigated, and changes in phase composition and microstructure before and after leaching process were also discussed. The results show that under the optimized conditions, including acid and ore in a mass ratio of 0.6, liquid-solid ratio of 4∶1, leaching temperature of 60 ℃, and leaching time of 3 h, the leaching rates of manganese and magnesium reach 99.36% and 83.97% respectively, while calcium is hardly leached out and mainly left in the residue as calcium sulfate.

The incineration slag of circuit board was doped with different proportions of copper concentrate, and then calcined at a high temperature to prepare oxygen carrier. The effects of doping amount of copper concentrate and calcination temperatures on the phase composition and morphology, as well as the oxygen absorption and desorption performance of the prepared oxygen carrier were all explored. The results indicate that CuFe₂O₄ is the main phase of the oxygen carrier, the formation of which can be improved by increasing the doping amount of copper concentrate and calcination temperature; the prepared oxygen carrier exhibits excellent lattice oxygen transfer capability; the mass weight of oxygen carrier in an air atmosphere increases by about 3% due to oxygen absorption, while the mass weight in a nitrogen atmosphere decreases by about 4% due to oxygen desorption.