An experimental study on mineral processing was carried out for the lean magnetite in M1033 Iron Ore from JISCO. After being crushed with high pressure grinding mill, the ore with a fineness of -0.030 mm 85% was processed using a magnetic separator with the magnetic field strength of 180~220 mT, resulting in an iron concentrate grading 65.18% TFe, with SiO₂ content of 5.21% and Fe metal recovery of 73.20%.

The influence of magnetite on bioleaching of chalcopyrite by Acidithiobacillus ferrooxidans was systematically explored by electrochemical tests such as open-circuit potential and cyclic voltammetry. Results show that the leaching rate of chalcopyrite can be increased by increasing the addtion of magnetite in the leaching system by undomesticated bacteria. The bacteria after domestication presents enhanced activity. With the addition of magnetite at an amount of 0.5 g, the copper leaching rate can be increased by around 8%. With the addtion of magnetite at an amout over 0.5 g, jarosite is generated during the leaching process, which can worsen the leaching environment, leading to the copper leaching rate just up by about 2%. The open circuit potential of chalcopyrite is always higher than that of magnetite in the system with different concentrations of Fe³⁺. During the galvanic reaction between chalcopyrite and magnetite, chalcopyrite acts as the cathode, which is not conducive to oxidation and dissolution of chalcopyrite. However, Fe³⁺in the solution can increase the corrosion rate of chalcopyrite, leading to an increased leaching rate of chalcopyrite.

An experiment on dynamic loading at high strain rate was conducted for T4 deformed ZK60 magnesium alloy by means of split Hopkinson pressure bar (SHPB). The experimental results show that the flow stresses of the ZK60 alloy samples increase with the increasing of strain rate. Observation of transmission electron microscopy results indicate that a large number of second phases precipitated in the alloy after dynamic loading. The hardness measurement results show that the hardness of material is elevated from 64.40HV to 93.05HV after dynamic loading at 3 000 s^-1. High-density dislocation is generated within the ZK60 alloy and numerous reinforcing phases (β′₁ and β′₂) precipitated in the matrix during deformation.

A low-grade manganese carbonate ore in Tongren of Guizhou Province has complicated mineral compositions, with a higher content of clay mineral illite (19.30%). In order to improve the mineral dressing index of this type of manganese ore resources, magnetic separation experiments was performed for it by using a high gradient magnetic separator. In the experiment, the mineral after pre-desliming was ground by a ball mill to a grinding fineness of -75 μm 69.62%. Then, it was subjected to a magnetic separation process consisting of one roughing and two scavenging, resulting in the final manganese carbonate concentrate grading 19.39% Mn at 83.66% recovery, with yield of 52.81%. The experiment results are of great significance for reducing the discharge of electrolytic manganese slag in Tongren.

After iron tailings was subjected to preconcentration followed by magnetizing roasting process, the obtained product was taken in an experiment to be processed respectively by adopting a grinding and magnetic separation process and a combined process of grinding plus magnetic separation followed by flotation process. The roasted ore with TFe grade of 33.19% was processed using a grinding and magnetic separation approach, resulting in an iron concentrate grading 63.04% TFe at 80.04% recovery at a grinding fineness of -0.025 mm 97%. Although the processing flowsheet is simple, it is still hard to achieve such a grinding fineness in commercial practice and the grinding cost is also extremely high. However, a process consisting of grinding, magnetic separation and flotation, with a grinding fineness of -0.025 mm 85%, can produce an iron concentrate grading 65.36% TFe at 73.39% recovery. Therewith, such grinding fineness is commercially practicable and the grinding cost can be obviously reduced.

Random Forest (RF) and eXtreme Gradient Boosting model (XGboost) were adopted to assess the landslide hazard in Changsha City, and frequency ratio (FR) was then used to check and verify the obtained result. A vulnerability assessment system was established based on analytic hierarchy process (AHP) and then adopted to make vulnerability assessment. Finally, efficient risk assessment was realized by integrating the results of hazard assessment and vulnerability assessment with numerical classification method. It is found that RF model is similar to XGBoost model in its evaluation performance, but XGBoost model regulated by FR method can bring a more accurate assessment. Also, the vulnerability assessment has the largest weight value of population density, and high vulnerability areas are mostly concentrated in downtown area and traffic arteries. The areas with relatively higher and high risk account for about 4.6% of the entire study area in Changsha City, which are mainly concentrated in valleys, towns and traffic arteries.

An all-weather moving target detection method by using Retinex algorithm based on HSV color space conversion was proposed for complex situation in a mine, which changed the detection of moving target to the detection of special marker on the moving target, and extracted the original grey image of the target by color space conversion. The histogram of grey distribution was used to judge whether to restore the low-illumination image. And special markers were selected in the scene, and the original image was converted to HSV color space. Then, the corresponding ROI region was selected, and the binary image was obtained based on the threshold value. After smoothing of the data, the Canny operator was used to extract contour information, thus characteristic parameters of the marker was extracted. The practice proves that the characteristic parameters of the markers can be accurately obtained by this method, which can thus solve the problem of connector falling off from mechanical equipment under complex situation. It is shown that this method is of certain practical significance in engineering application.

Mo-Bi bulk concentrate is usually processed with a longer flowsheet at higher cost, and the traditional bismuth smelting processing technique also features longer flow, high energy consumption, as well as lower bismuth recovery. In order to solve those problems, an oxygen-rich hydrochloric acid leaching process was adopted in an experimental study on beneficiation of Mo-Bi bulk concentrate, and the effects of HCl concentration, leaching time and temperature on the leaching rates of Mo and Bi were investigated. It is shown that oxygen-rich hydrochloric acid leaching at 80 ℃ for 6.0 h, with HCl concentration of 3 mol/L, liquid/solid ratio of 3 ∶ 1, and stirring speed of 500 r/min, can result in the Bi leaching rate up to 99.13% and Mo left in the leaching residue. Thus, molybdenum and bismuth can be efficiently separated. The obtained leaching solution is then subjected to purification for purity removal and replacement with iron plate, and the finally obtained sponge bismuth can have purity exceeding 99%.

As for a kind of low-calcium and low-magnesium stone coal featuring low alkalinity and high content of silica, a process of sulfuric acid curing followed by water leaching was adopted in an experiment, and the effects of grain size, sulfuric acid dosing, curing temperature and curing time on vanadium leaching were investigated. The results show that the leaching rate of vanadium reaches 88.6% when the raw ore with grain size of -0.15 mm was cured at 120 ℃ for 8.5 h by adding sulfuric acid at 20%, and then water leaching at the room temperature for 2 h with liquid and solid at a ratio of 2∶1. During the curing process, the mica structure with the locked vanadium therein is effectively dissociated and soluble vanadium is released. It is shown that the leaching solution has a lower content of silicon (0.08 g/L), significantly reduced compared to the process of direct acid leaching or the process of roasting plus acid leaching, which is beneficial to the subsequent extraction process.

In an experiment for Cu/Mo separation of a copper-molybdenum bulk concentrate, ozone oxidation technique was applied to enhance floatability difference between chalcopyrite and molybdenite. Under adequate ozone oxidation conditions, a molybdenum concentrate grading 47.46% Mo at 94.96% recovery, with Cu content of 0.10% can be obtained from a closed-circuit flotation test adopting a flowsheet consisting of one stage of roughing and three stages of cleaning. It is shown that the flotation indicators obtained by applying ozone oxidation technique is superior to that by using Na₂S as the depressant, which indicates that the ozone oxidation technique can be used to substitute Na₂S depression approach for Mo flotation whilst depressing Cu.