In order to comprehensively recover titanium resources and iron resources from a low-grade ilmenite ore, an experimental study was performed for the ore by a process of low intensity magnetic separation (LIMS) followed by regrinding and re-concentration to recover Ti and Fe therein. The results show that LIMS with ore at a grinding fineness of－0.074 mm 84.78% can yield an iron concentrate grading 62.82% TFe and 3.62% TiO₂ with iron recovery of 51.32%, presenting a good recovery of magnetic iron; the obtained LIMS concentrate is subjected to high-intensity magnetic separation (HIMS) consisting of one roughing and one cleaning, followed by gravity separation with a shaking table, resulting in the obtained Ti concentrate grading 40.81% TiO₂ at 18.47% recovery. It is shown that both Fe and Ti therein can be comprehensively recovered.

To address the problems of poor fluidity and high viscosiy, ore rocks and higher ore losses and dilution due to the influence of moisture content on eastern stopes of Jinshandian Iron Mine, the variation laws of fluidity of ore blocks, shape characteristics of drawn ore blocks, as well as loss and dilution indices of two types of ore bodies in the eastern stopes under influence of different moisture content were analyzed by preforming physical tests and numerical simulation. A reasonable range of drift spacing for the eastern stopes was determined, which was then optimized from the perspectives of safety, technology and economy, based on the improved CRITIC-TOPSIS evaluation method. The results show that with the moisture content in a range of 0－8%, the drawn ore blocks in the eastern stopes are in a shape of an “inverted water drop”, and become shallow as the moisture content increases; with the moisture content in a range of 4%－8%, the natural angle of repose of ore rocks increases with the increase of moisture content, the recovery rates of those two ore bodies are negatively correlated with moisture content, and present an upward trend followed by a decline as the drift spacing becomes wider, while the dilution rate follows the opposite trend. With the moisture content at 6% on average, the optimal drift spacing in the eastern stopes of Jinshandian Iron Mine should be set at 15 m.

To explore the impact of near-surface ore body mining on the stability of overburden and dangerous rock masses of slopes, a phosphate mine was taken as an engineering project in the study. The stability of the dangerous rock mass of the slopes was determined by on-site investigation, and the evolution of deformation, stress and plastic zone of overburden under different mining schemes were simulated with FLAC^3D software. The research results indicate that structural planes between layers of surrounding rock on the roof of stope are well-developed, probably causing falling debris in blocks or flakes. The strata are hard and brittle in lithology and have developed rock fractures. Under unloading effect of high and steep slopes, dangerous rocks are prone to be separated along the combination of fractures and strata plane, forming dangerous rock masses. The response law of the maximum stress in the overburden is similar to the law of the unbalanced force in numerical calculation. There is relatively small disturbance generated during mining process, which brings a little impact to the stability of adjacent stopes and surface. It is found that the ground surface is less affected by underground mining, with the deformation within the maximum limit value specified in the standard. If Ph2^# ore body is mined after Ph1^# ore body, the overburden can have relatively small displacement, and no connectivity in the plastic zones is occurred in the mining pillars, stopes and overlying strata.

Although the annual production of low-concentration microfine-grained ilmenite in Pan-Xi region attains over 1 million tons, it is not conducive to adopt flotation process for the subsequent titanium selection due to the microfine particle size, large volume and low concentration of this ore. For this resource, comparative experiments were conducted based on two major flowsheets, including “SLon high-intensity magnetic separation + flotation” and “desliming using new type of cyclone+flotation”. The results show that the latter process flowsheet has a lower consumption of reagents, and the obtained titanium concentrate has better indicators, with a titanium concentrate grading 47.06% TiO₂ at 59.03% recovery with the yield of 20.22%.

The south slope of the Jingxi-Barak mining area of Xinjiang Jinchuan Mining Industry was taken for study. As for the issues of weakening mechanical parameters of slopes after an earthquake and the stability assessment of slopes under aftershocks, a BP neural network model optimized by the crow search algorithm (CSA-BP) was proposed for the inversion of mechanical parameters of slopes after an earthquake. The stability of slopes with dangerous rock mass under aftershocks was evaluated by using the discrete element method. The results show that the CSA-BP model can quantitatively reveal the weakening characteristics of rock masses through the inversion of mechanical parameters. Under aftershock of a magnitude 5 earthquake, significant displacement occurs in the tuffaceous sandstone in the middle and upper parts of the slope, with horizontal (x-direction) displacement far exceeding vertical (z-direction) displacement, indicating that slope instability is dominated by horizontal sliding. The CSA-BP model can accurately identify high-risk zones through a parameter-dynamic coupling mechanism, providing theoretical support for slope protection after earthquakes.

Constitutive models of HJC and RHT for different in-situ stress conditions were established by adopting ANSYS/LS-DYNA software, and the effects of blasting on effective stress and rock damage in different constitutive models were analyzed comparatively. The results show that the effective stress variation in the HJC model is more consistent with practical scenarios, while the rock damage in the RHT model can better reflect practical conditions. In-situ stress has a minor impact on effective stress in regions close to blast holes but a significant influence on effective stress in areas farther away. Additionally, in-situ stress has a smaller effect on rock damage in the HJC model, but substantially affects the damage variables in the RHT model.

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.

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.

As for the molybdenum ores from Yichun Luming Mine, an m-order grinding kinetics model was used to explore the effects of four grinding aids, such as triethanolamine (TEA), triisopropanolamine (TIPA), polyacrylic acid (PAA) and polycarboxylic ether (PCE), on grinding kinetics of molybdenum ores. The results show that before addition of grinding aids, the proportion of the milled product in the size range of -0.074 mm increases significantly with the increase of the medium charge ratio, and the grinding kinetic parameters of m and k all increase; with the same medium charge ratio, the parameter of m increases and the parameter of k decreases as the grain size of milled product decreases. Comparatively, as for the samples milled with grinding aids of TEA, TIPA, PAA and PCE, the milling products in the size range of -0.074 mm increase by 6.19, 2.40, 3.62 and 1.89 percentage points, respectively. Compared to the system without grinding aids, an addition of TEA can lead to higher values of parameters of k and m, and larger particle size can result in great decline in the k value, while small particle size can bring a gentle k-grain curve, indicating the k value plays a dominant role at the initial grinding stage. After addition of grinding aids, the grains present improved dispersibility with significantly less agglomeration.

Based on process mineralogy study, a processing technique consisting of atmosphere roasting and leaching with dilute sulfuric acid was proposed to separate a kind of mixed rare earth concentrate containing 48.23% REO. It is found that the phase composition of such concentrate is mainly composed of bastnaesite, monazite, apatite and fluorite, with rare earth elements primarily existing in bastnaesite and monazite. Under air/argon atmosphere roasting, phases of monazite, apatite and fluorite can remain stable, and phase transition is mainly attributed to bastnaesite reaction. In an air atmosphere, bastnaesite is transitioned in the following steps, CeFCO₃→Ce₇O₁₂→Ce₁₁O₂₀→CeO₂, while its transition steps in an argon atmosphere include CeFCO₃→Ce₇O₁₂, Th_0.5Ce_0.5O_1.84→CeOF. After roasting in an air atmosphere at 500 ℃ followed by leaching with dilute sulfuric acid, the leaching rates of F-REO and P-REO can reach 86.67% and 1.70%, respectively, while the process of roasting at 700 ℃ in an argon atmosphere can lead to the leaching rates of F-REO and P-REO at 75.97% and 13.33% respectively. And the leaching residues obtained from above-mentioned two different processes have F-REO and P-REO contents of 6.92%, 26.02% and 11.86%, 21.81% respectively, all dominated by monazite. It is concluded that this processing technique of atmosphere roasting followed by dilute sulfuric acid leaching can effectively achieve separation between bastnaesite and monazite.