Some typical rock was taken as the sample in an experiment to study the mechanical properties of white sandstone under uniaxial compression with strain rates ranging from 10^-5 s^-1 to 10^-3 s^-1. The surface displacement contours of the samples were observed and collected by using 3D-DIC system, and the difference in the deformation and failure characteristics of samples under the effect of different strain rate was also analyzed. The results show that the variation of displacement field on the surface of rock sample reflects an evolution law of failure surface, and there is a corresponding relationship between shear failure plane and concentrated displacement field. The difference in the overall axial strain mainly occurs during the period from micro-crack compaction to elastic deformation. At an initial stage of loading, there is difference in the overall radial strain. The lower end part of the sample has the largest radial displacement when the strength reaches the peak, while the upper end part is deformed under the impact of the end effect. The radial outward expansion is limited by the friction between the end face and the gasket. In addition, the local axial strain at the lower end is greater than that at the upper end. With an increase in the loading rate, rock sample has its mechanical characteristics converted from ductility to fragility. During the failure process of rock sample under the uniaxial compression with a lower loading rate, the occurred pore collapse results in friction effect due to the closure again and slippage of some cracks, thus there appears fluctuation in the stress-strain curve near the peak strength. It is shown that the mechanical parameters (peak strength, elastic modulus and Poisson's ratio) of white sandstone increase as the loading rate increases.

A technique of nanofiltration combined with ammonium sulfide precipitation was verified for its feasibility of separating and recovering ammonium nitrate and nickel nitrate from nickel-containing feed solution. Based on investigating the effects of pressure on the side of concentrate stream in nanofiltration, stages of nanofiltration and pH value of ammonium sulfide precipitate, an appropriate route was determined, including two-stage nanofiltration, KLNi-01 ion exchange to remove nickel, nickel precipitation with ammonium sulfide, and dissolution with nitric acid to recover nickel nitrate. The feed stream with pH of 6 was subjected to a two-stage nanofiltration, with pressure of 0.8 MPa on the side of concentrate stream. The obtained permeate stream with nickel content decreased to 0.181 g/L was adsorbed with KLNi-01 resin, leading to the nickel content therein further reduced to 0.002 mg/L. Then, 36 mL/L ammonium sulfide solution was added into the concentrate stream with an initial pH of 6 for nickel precipitation. The generated solution had nickel content of 4.7 mg/L, and no sulfide was detected, while the obtained precipitate of nickel sulfide was then dissolved with nitric acid, and the nickel nitrate solution was obtained with concentration of 258.40 g/L. The material balance calculation shows that treatment of 1 m³ of nickel-containing feed stream can generate 0.3 m³ permeate, and 192.93 L of nickel nitrate solution with concentration of 258.40 g/L can be generated with the consumption of 25.20 L of ammonium sulfide solution with concentration of 20%-26%, 37.22 L of concentrated nitric acid and 109.05 L of water.

The phase composition and morphology of a molten mixture of steel slag and furnace slag prepared at a high temperature was analyzed by X-ray diffraction and SEM-EDS scanning electron microscope to investigate the effect of MgO doping. The results show that MgO doping can effectively inhibit the formation of MgFe₂O₄ phase and non-gel Ca₂Al₂SiO₇ phase, and promote the formation of MgFeAlO₄ phase, thus increasing the melting point of the mixed slag. It is found that the mixed slag after doping 2% MgO presents a layered structure on its cross section. The inner layer has an increased proportion of MgFeAlO₄ phase, with uniform and fine pores; and the MgFeAlO₄ phase is wrapped by MgFe₂O₄ spinel with layered structure in the middle part; and the outer layer has Ca₂Al₂SiO₇ phase with uniform pores and moderate density. The mixed slag with such kind of structure is suitable to be used as the filter material for removing heavy metal ions.

With micro-nano TiC as reinforcing phase and nickel powder as matrix powder, a TiC reinforced Ni-based coating was fabricated by laser cladding technology, and the effect of TiC on microstructure and wear resistance of the coating was investigated. The results show that Ni-based coating has its microstructure predominately composed of γ-Ni and TiC, and a high content of TiC is prone to cause TiC segregation at the top of coating. With the increase of TiC content, coating will have its hardness increase gradually, especially have an obvious improvement in the surface hardness. A three-body wear test shows that the wear resistance of this composite coating decreases as TiC content increases, indicating that the brittle reinforcement phase is not conducive to improving wear resistance of the coating under impact load.

In processing a mud-bearing high-silver lead-zinc sulfide ore, collectors of dimethylphenyl dithiophosphate and aniline aerofloat were used in combination to collect lead minerals in a low alkali environment, while the noble metal of silver was comprehensively recovered. Furthermore, lime combined with 8372CN were used to depress pyrite in zinc flotation process, thus alleviating the influence of sludge on the quality of zinc concentrate. The closed-circuit flotation test yielded a lead concentrate grading 67.18% Pb at 94.57% recovery, 2 560.37 g/t Ag at 80.54% recovery and 3.60% Zn, and a zinc concentrate grading 51.63% Zn at 93.27% recovery. With this flowsheet, an efficient comprehensive utilization of a mud-bearing high-silver lead-zinc sulfide ore can be actualized.

A surfacing layer of Babbitt alloy was prepared on the surface of steel 20 by cold metal transfer (CMT) welding. And the metallographic morphology, phase composition, microstructure, element distribution, hardness and friction coefficient of the surfacing layer were analyzed by using metallographic microscope, X-ray diffractometer, scanning electron microscope, energy dispersive spectrometer, Vickers hardness tester, as well as friction and wear tester. The results show that the phase structure of surfacing layer of Babbitt alloy does not change and is composed of hard point SnSb phase, Cu₆Sn₅ phase and soft matrix α-Sn phase. A lower heat input leads to a rapid cooling rate for the surfacing layer of Babbitt alloy, and the surfacing layer with a finer grain size has hardness around 40HV_0.1, much higher than that of cast Babbitt alloy. As the microhardness increases, the friction coefficient and specific wear rate of Babbitt alloy fall down to 0.31 and 1.38 × 10^-5 mm³/(N·m), respectively. Based on the study of the wear mechanism, it is found that the surfacing layer of Babbitt alloy principally experiences abrasive wear. CMT welding can effectively improve the hardness and wear resistance of Babbitt alloy.