A thick layer of accumulated debris after landslide is distributed on the slope in the middle of site. And the debris will lose stability due to excavation of slope, resulting in an unstable slope. The physical and mechanical parameters of those accumulated debris after landslide were determined by performing indoor tests and inverse analysis. According to the site environmental conditions and the distribution characteristics of rock and soil layers, the overall and local stability and deformation characteristics of slope under different working conditions were analyzed by simulation with software. Also, the stability and development trend of slope in the middle of site were comprehensively evaluated. Based on the stability analysis and evaluation results, a corresponding prevention and control suggestion is put forward.

A foreign copper sulfide concentrate from slag processing was treated by adopting heated sulfuric acid leaching with trivalent iron compound as an oxidant for recovering copper therein. The effects of oxidant dosage, leaching temperature, leaching time, initial concentration of sulfuric acid and liquid-solid ratio on the leaching rate of copper from copper sulfide concentrate were investigated. The results show that with the proper condition, including the oxidant of hematite at an amount of 0.2 g/g ore, leaching temperature of 85 ℃, leaching time of 6 h, liquid-solid ratio at 5∶1, and sulfuric acid with initial concentration of 200 g/L, the copper leaching rate can reach 97.96%. A verification test with different oxidants shows that hematite and magnetite present good oxidability in acid leaching system, leading to the copper in those copper sulfide concentrate leached out at a medium temperature. Also, the higher the purity of trivalent iron compounds, the better the oxidative leaching effect of copper.

Aiming at the problem of high fragmentation by blasting in Baiyinnuoer Lead-Zinc Mine, the unit consumption of explosive and delay intervals between rows in a fan-shaped pattern of blastholes with medium depth were analyzed by numerical simulation with ANSYS/LS-DYNA. According to Von Mises yield criterion, the effective stress, peak value of vibration velocity, and rock damage area of the recorded unit were analyzed. The results show that with unit consumption of explosive at 1.16 kg/m³ and delay interval of 100 ms between rows, the effective stress, peak value of vibration velocity and rock damage area of the recorded unit all can meet the design requirements. The optimized parameters of unit consumption of explosive and delay interval were then applied in on-site blasting with blastholes in a staggered array. The muck pile after blasting was analyzed by using Split-Desktop 4.0, and it is found that the rock fragmentation by blasting is 4.34%, indicating that high fragmentation by blasting can be effectively controlled.

With the polymetallic tailings from Chenzhou of Hunan Province as the research object, an approach of macro volume and mass separation according to the composition of tailings was proposed for a comprehensive utilization. Firstly, magnetic separation was used to sort out iron-aluminum minerals, and then the non-magnetic minerals were processed to obtain calcium and silicon minerals by adopting a flotation process consisting of one stage of roughing, two stages of scavenging and seven stages of cleaning, with sodium oleate as the collector, sodium carbonate as the regulator, and the mixture of GLY-Ⅲ and sodium hexametaphosphate as the depressant. The as-obtained iron-aluminum minerals contain 40.17% garnet at a recovery of 94.08%. The obtained calcium mineral has a Ca grade of 58.00% at a recovery of 50.29%, with the content of fluorite therein reaching 76.47%, while the silicon mineral has a Si grade of 27.96% at a recovery exceeding 99%. These three products all meet the requirements for preparing building materials such as cementing materials and ceramic aggregates, providing new methods and ideas for high consumption of tailings.

In order to clarify the influence of geometric parameters of tapered pipeline on particle flow characteristics in pneumatic conveying, numerical simulation was conducted for horizontal pipelines with 5 kinds of taper ratio and taper length by adopting CFD-DEM coupling method. Influence of geometric parameters of taper ratio and taper length on particle velocity, pressure loss and Froude number in tapered pipeline was investigated. The results show that tapered pipe can reduce particle velocity. As taper length and taper ratio increase, particle velocity increases first and then decreases. And the tapered pipe can also reduce pressure drop in pipeline. As taper ratio and taper length increase, pressure loss in pipeline increases. The higher the taper ratio, the smaller the Froude number in tapered pipe is. As taper length increases, the Froude number decreases more slowly.

Experimental study was conducted on the properties and beneficiability of a refractory scheelite ore from Luanchuan of Henan Province. The results show that the WO₃ grade for this diopsidite garnet skarn-type molybdenum-tungsten ore is 0.067 2%, and scheelite is the dominant tungsten minerals. This ore is prone to become sliming and also has high content of calcium-bearing gangues, which are unfavorable to scheelite recovery. With a flotation reagents scheme including regulator sodium carbonate 1 500 g/t, depressor sodium silicate 600 g/t, depressor SG 40 g/t, and collector FX-6 400 g/t, a closed-circuit test was performed with the tailings from molybdenum flotation for scheelite flotation. As a result, the roughing stage in the closed-circuit test produced a rough scheelite concentrate grading 1.472% WO₃ at 83.54% recovery, and the cleaning stage produced a scheelite concentrate grading 31.92% at 95.71% recovery. By using a combination of sodium silicate and SG, the recovery efficiency of scheelite can be effectively improved, which is favorable for subsequent large-scale industrial production.

Experiments were carried out for alumina ceramics with rotary ultrasonic-assisted and ordinary milling-grinding processes respectively by using a small diameter electroplated grinding wheel. The variation of grinding force with ultrasonic power, linear speed of grinding wheel, feed rate and grinding depth during milling-grinding of alumina ceramics was analyzed. The results show that with ultrasonic power from 0 W up to 90 W and other parameters keeping constant, the grinding force is in decline and the surface topography is significantly improved. As the linear speed of grinding wheel increases, while the feed rate and grinding depth decrease, the grinding force in both rotary ultrasonic-assisted and ordinary milling-grinding processes decreases. With the processing parameters in the tested range, the grinding force in rotary ultrasonic-assisted milling-grinding process is lower compared to the ordinary milling-grinding process. Besides, the maximum reduction in normal and tangential grinding force of rotary ultrasonic-assisted milling and grinding can reach 24.17% and 23.30% respectively.

To address the problems of low recognition accuracy and slow speed of current plate shape pattern recognition methods, a pattern recognition model for cold-rolled strip plate shape based on IHPO-KELM was proposed. Firstly, kernel extreme learning machine (KELM) network was adopted to reduce the number of initial parameters in the network and improve the accuracy and speed of plate shape recognition. Secondly, Levy flight mechanism was added to the improved position update formula for linear combination by using the population of the predator algorithm initialized based on Sine chaos mapping, so as to improve the accuracy of the predator (HPO) algorithm, as well as to address the problem of HPO easily falling into local precocity during the iteration process. Then, the improved predator algorithm was used to optimize the regularization and kernel parameters of the KELM network model, as well as improve the accuracy of plate shape recognition. Finally, the Matlab simulation results have verified that the IHPO-KELM algorithm has the advantages of simple network structure, high convergence speed, and high recognition accuracy. The recognition accuracy of IHPO-KELM algorithm in identifying the measured data of 900HC reversible cold rolling mill of a company is higher than the KELM recognition model optimized with sparrow algorithm (SSA-KELM) by 58.8%, indicating a good generalization ability of IHPO-KEM recognition model. This provides a new idea for efficient and intelligent recognition of plate shape defects.

A silicothermic process was adopted to extract phosphorus, and the main chemical reactions and Gibbs free energy were clarified by thermodynamic calculation. The feasibility of the process was then verified by performing practical experiments. The main reaction of silicothermic process for phosphorus extraction is as follows: 2 (3CaO·P₂O₅)+5Si+SiO₂ ==== 2P₂(g)+6CaO·SiO₂. The vacuum degree can promote the reaction to proceed in the forward direction, and a reaction system with lower pressure can lead to smaller standard Gibbs free energy of the reaction, leading to silicothermic reduction reaction occuring much easier. Increasing temperature can promote the reaction to proceed in the forward direction, and prolonging reduction time properly at the same temperature can improve the reduction rate of the reaction. After a reaction at 1 250 ℃ for 2.5 h under normal pressure, rough phosphorus (yellow phosphorus) with purity of 95.03% can be obtained by adopting silicothermic process, and the content of residual phosphorus in the dry slag is 1.45%. It is shown that using siliceous reductant in the silicothermic process for preparing yellow phosphorus can avoid the usage of coke, which conforms to low-carbon development strategy.

The acid leaching solution of electrostatic precipitator dust from copper smelting has a high concentration of sulfuric acid, in which the iron and arsenic exist in the form of Fe³⁺and As⁵⁺, thus it is decided to adopt arsenic sulfide residue as the precipitant for copper precipitation. Firstly, an experiment was performed on the addition of arsenic sulfide residue in single Cu²⁺ and Fe³⁺ solution with different acid concentrations. Based on that, an experiment was performed for copper precipitation and arsenic leaching in the actual acid leaching solution. The results show that in the process of copper precipitation with arsenic sulfide residue, oxidation and reduction reactions between Fe³⁺ and S^2- occur firstly, which is followed by oxidation and reduction reactions of As⁵⁺ and S^2-, and finally a sulfurization reaction for precipitation of Cu²⁺. When the addition of arsenic sulfide residue is at an amount of 1.4 times the theoretical amount, it is shown that the copper precipitation rate is relatively higher, but the rate of arsenic dissolution is lower.