An experiment on non-quenched and tempered steel F45MnVS was carried out by adopting controlled cooling after hot rolling. The mechanical properties, decarburized layer and microstructure of rolled steel without cooling and after controlled cooling process were compared for analysis. The results show that controlled cooling after hot rolling can lead to the steel with yield strength, elongation, section shrinkage and impact energy improved all, and with the decarburized layer being effectively controlled or even "disappeared". With the surface temperature of the hot-rolled steel decreased to 650 ℃, granular bainite begins to occur on the steel surface; with the surface temperature down to 460 ℃, much granular bainite occurs on the steel surface. It is shown that by using controlled cooling after hot rolling, the ferrite and pearlite on the steel surface and near 1/2 radius on the cross section of the steel become fine-grained. The total ferrite net is reduced, and long strip ferrite is transformed to blocky ferrite. Due to larger size, the central part of steel shows little difference in the microstructure.

In consideration of safety problem of landfilling into a dump with inclined foundation in an open-pit mine, an inclined foundation model and an anti-slide coal pillar model were established based on the analysis of landfilling methods in such inclined dump, deformation characteristics and sliding mode of inclined foundation, and then the method for evaluating stability of anti-slide coal pillar and influencing factors of the stability coefficient of dump slope were all discussed. The research results show that the stability of anti-slide coal pillar mainly depends on the relationship between the internal friction angle of coal pillar and the rest angle of waste material. When the internal friction angle is greater than or equal to the rest angle, the stability coefficient of dump slope increases with an increase in the length of anti-slide coal pillar; while when the internal friction angle is less than the rest angle, the stability coefficient of dump slope increases first, then falls down and finally increases again as anti-slide coal pillar becomes longer.

A technique featuring separated treatment and recycling was introduced to process a mineral processing wastewater from a tungsten-copper ore concentrator. The wastewater from copper tailings precipitation and copper concentrate filtration is recycled for copper flotation, while the water from tungsten concentrate filtration is returned to the cleaning stage in tungsten flotation. They all can meet the water quality requirement in beneficiation. Tungsten tailings water can be reused in grinding and tungsten flotation after intensified treatment by lime flocculation and Fenton oxidation processes. In a close-circuit test, each type of wastewater from different beneficiation processes was separately returned to the corresponding stages based on its quality, and the obtained technical indicators were equivalent to those from the tests with fresh water.

In order to solve problems including serious atmospheric pollution by sulfur-containing flue gas and utilization of red mud, sulfur-containing flue gas was treated by using a wet process with red mud. Under the following optimal process conditions, including liquid-solid ratio of 9∶1, flue gas at a temperature of 60 ℃, liquid-gas ratio of 8.0 L/m³, liquid with pH of 5.6 for desulfurization, the SO₂ concentration in flue gas can be reduced from 5 000 mg/m³ to less than 35 mg/m³, meeting a standard of ultra-low emissions. In an industrial experiment on desulfurization with red mud for the flue gas from a 75 t/h coal-fired boiler, the SO₂ concentration in the low-sulfur flue gas was reduced from 4 100 mg/m³ to less than 30 mg/m³, with removal efficiency up to 99.68%；while the SO₂ concentration in the high-sulfur flue gas was reduced from 10 600 mg/m³ to less than 35 mg/m³, with a removal efficiency up to 99.89%. Based on the comparison between this wet desulfurization with red mud and with limestone-gypsum flue gas desulfurization process, it is found that the wet flue gas desulfurization process with red mud as desulfurizer can have the operation cost reduced by 20.05% for the treatment of same volume of flue gas with the same SO₂ concentration.

As for a cobalt-containing raffinate in Africa, several neutralizing agents, including limestone, lime, limestone-lime, as well as a combination of flotation tailings and lime, were separately used for impurity removal in the study, and a preliminary economic evaluation was also conducted. It is found that a combination of flotation tailings and lime is a good choice for impurity removal by neutralization, which can not only save the usage of limestone, but also recover part of the copper and cobalt in flotation tailings. Using this process, the leaching rates of copper and cobalt from flotation tailings can reach 81.69% and 41.10%, respectively. After an addition of lime, the precipitation rates of copper and cobalt can reach 95.43% and 13.64% respectively, and the iron removal rate is up to 99.86%.

The amphibolite-type magnetite ore in Yuanjiacun Iron Mine was processed adopting a processing technique consisting of high pressure grinding roll (HPGR) plus pre-concentration, followed by staged grinding and staged separation process. In order to reduce the grinding feed in the following concentration, HPGR was introduced for superfine crushing, and the obtained material in a size fraction of－3 mm was treated by a wet pre-concentration process, yielding 22% coarse tailings for discarding. And then a pre-concentration process resulted in the obtained concentrate with TFe grade up to around 36%. The work index for grinding before and after adopting HPGR was reduced from 11.91 kW·h/t to 11.11 kW·h/t. An experiment was performed with a flowsheet of HPGR plus pre-concentration followed by staged grinding and staged separation process, yielding 33.92% concentrate grading 67.13% TFe at 75.75% recovery, showing the ratio of concentration down to 2.27 from 2.95. It is concluded that the above-mentioned processing technique can provide an energy-conservation and consumption-reduction solution for large-scale and low-cost exploitation of similar low-grade magnetite mines.

The problems of oxidation and corrosion of LIBs copper foil in its production and application have restricted its service life and battery safety. Based on the research status of anti-oxidation technologies for LIBs copper foil in recent years, the mechanism of different passivation methods is summarized. After an introduction of the corrosion mechanism of copper foil fluid in Li-ion battery electrolyte, the research progress in improving corrosion resistance by modification of copper foil surface is reviewed. On this basis, the prospects of chromium-free passivation technology and surface modification technologies for copper foil are presented. At last, a clean, eco-friendly and efficient anti-oxidation and anti-corrosion concept is proposed.

The motion of spherical, tetrahedral and hexahedral particles flowing in a vertical pipe under different working conditions was simulated by using computational fluid dynamics-discrete element method (CFD-DEM), and the motion of irregular particles flowing in a vertical pipe was obtained. Based on comparison of local concentration and local flow rate, it is found that with lower flow rate at the inlet, the shape of particles can bring a larger influence to local concentration; while with a higher feed concentration and lower inlet flow rate, the shape of particles can bring obvious influence to local flow rate.

With sodium oxalate and D401 chelating resin as impurity removal materials, impurities of calcium and magnesium in crude lithium solution were removed by adopting a process consisting of chemical precipitation and ion exchange. In an experiment, reaction was firstly run at 25 ℃ for 60 min by adding sodium oxalate at an amount of 17.6 times the theoretical value, with pH of 6.5 and stirring rate of 300 r/min. And then, the lithium solution after filtration flowed through a resin column at a rate of 8 BV/h. As a result, the removal rates of calcium and magnesium reached 98.21% and 83.36%, respectively, and the lithium loss rate was 5.34%. The purified lithium solution was then recrystallized and purified, and the obtained lithium phosphate powder, with regular morphology and uniform dispersion, has its purity higher than 99.5%.

Natural chalcopyrite (CuFeS₂) was used as a catalyst to activate persulfate (PS) for butyl xanthate wastewater treatment. The influences of CuFeS₂ dosage, PS dosage and initial pH of solution on the removal rate of butyl xanthate in CuFeS₂/PS system were investigated, and the recyclability of CuFeS₂ was also evaluated. The results show that CuFeS₂ can significantly activate PS. After 10 min reaction with initial pH of 3, CuFeS₂ dosage of 4 g/L and PS dosage of 5 mmol/L, the removal rate of butyl xanthate reached 99.23%, while the removal rate of total organic carbon (TOC) was only 31.29%. After the reaction time was extended to 60 min, the TOC removal rate reached 68.31%, and CuFeS₂ still sustained good catalytic activity after being recycled for five times. The UV-Visible absorption spectra of butyl xanthate wastewater degradation showed that butyl xanthate was initially oxidized to alcohols, then decomposed and mineralized to carbon dioxide and water. X-ray diffraction and fourier transform infra-red spectroscopy analysis showed that CuFeS₂ reacted with PS without surface passivation, thus could be reused. A free radical quenching test and an electron spin resonance analysis showed that the removal mechanism of xanthate included free radical degradation and CuFeS₂ physisorption, in which sulfate radical (SO₄^-·) and hydroxyl radical (HO·) were the main active substances to promote xanthate degradation, and the SO₄^-· played a dominant role.