High-strength and high-conductivity Al-0.65Mg-0.58Si-0.17Fe alloy wire was prepared by adopting horizontal continuous casting process followed by continuous extrusion and drawing processes, and effects of such processing technique and heat treatment on microstructure, mechanical properties and conductivity of the prepared alloy were investigated. The results show that the processing technique of horizontal continuous casting plus continuous extrusion can improve the solid solubility in supersaturated alloy and lead to significantly grain refinement, and the following drawing process introduces high-dense dislocation, which changes the precipitation behavior of Mg₂Si phase during the ageing treatment of the alloy. It is shown that Al-0.65Mg-0.58Si-0.17Fe alloy prepared by the processes of horizontal continuous casting, continuous extrusion and drawing is subjected to 3 hours of aging treatment at 155 ℃, resulting in its tensile strength of 335 MPa, elongation rate of 6.9%, and electrical conductivity of 55.7%IACS.

The expanded graphite (EG) derived from the graphite anodes of spent lithium-ion batteries was taken as conductive substrate, and then Sn/Co-based bimetallic sulfide was loaded by using a hydrothermal method to synthesize SnCoS₄@EG nanocomposite. And such EG presents a cross-linked porous three-dimensional lattice, and the SnCoS₄ nanocrystals in the synthesized composite are uniformly dispersed in the EG, which enhances electrical conductivity of electrode material and stability of metallic sulfide, but also increases the contact area between active sites and electrolyte, leading to a higher exchange rate of Li⁺ ions at electrode/electrolyte interface. It is shown that SnCoS₄@EG electrode can exhibit a reversible specific capacity of 1 195.90 mAh/g at 1.0 A/g after 500 cycles, presenting excellent durability over a large number of cycles.

Surface mechanical attrition treatment (SMAT) was adopted for low-carbon steel materials to achieve surface nanonization, and then the influence of surface nanonization on corrosion resistance of low-carbon steel was also discussed. The results show that due to surface nanonization, the low-carbon steel has a greater plastic deformation on the surface as the carbon content decreases, and the X-ray diffraction of its surface presents obviously wider peaks. It is found that after nanosizing treatment for the surface of low-carbon steel with different carbon content, the lower the carbon content, the rougher the surface and the worse the corrosion resistance.

A FeCoCrNiMn high-entropy alloy (HEA) coating was prepared on the 201 stainless steel surface by adopting high-speed laser cladding technology, and then the microstructure, phase distribution, microhardness of FeCoCrNiMn coating, as well as its wear properties in dry sliding condition were all investigated. It is found that such laser cladded FeCoCrNiMn HEA coating consists of a single FCC structure, with no obvious cracks observed. It also forms a good metallurgical bond with the substrate. The microhardness of the coating is around (439±2.1) HV, nearly two times that of 201 stainless steel substrate, and the strengthening mechanisms mainly include strengthening by grain refinement and solid solution strengthening. Also, the FeCoCrNiMn coating presents an obviously better wear resistance than 201 stainless steel, with an average friction factor of 0.246 and a specific wear rate of about 2.59×10^-6 mm³/(N·m). The wear mechanisms for it include adhesive and abrasive wear. It is concluded that such FeCoCrNiMn HEA coating prepared by high-speed laser cladding technology can significantly improve the surface hardness, wear resistance and service life of machine components.

In order to analyze mechanical properties of conveying hose during deep-sea mining operation, a mechanical model was established with Abaqus software for the buffer, flexible hose, and mining vehicle under different working conditions to analyze effects of buoyant ball position, buoyant force, ocean current velocity and volume fraction of conveyed mineral ores on hose configuration, as well as effect of forces that flexible hose exerts on the mining vehicle. When buoyant balls are put on the position far away from a mining vehicle, the hose is prone to be dragged on the seafloor；while being closer to a mining vehicle, the hose is prone to be entangled. It is shown that the closer to a mining vehicle, the greater the buoyant force and the greater the forces that the hose exerts on the mining vehicle. Furthermore, slower current velocity is more likely to bring greater impact to the hose configuration. The velocity of ocean current will influence the direction, magnitude and variation of the forces exerted on the mining vehicle. It is suggested that with ocean current at a velocity of 0.2 m/s, buoyant balls should be put on the position 12 m away from the buffer, with buoyant force selected at 1 500 N. In this case, the maximum horizontal and vertical tensile forces of the hose on the mining vehicle are 941 N and 1 258 N, respectively.

The acid leaching solution of cathode materials from spent lithium iron phosphate batteries was taken as raw material, and iron, phosphorus and lithium elements therein were recovered by adopting an oxidation-precipitation process. The effects of factors, including endpoint pH value of reaction system, reaction temperature, concentration of sodium hydroxide, dripping rate of sodium hydroxide, and the volume ratio of hydrogen peroxide to acid leaching solution, on the precipitation rates of iron and phosphorus and the loss of lithium during the precipitation process were all investigated. Results show that with the endpoint pH value of 2.5, temperature of 75 ℃, sodium hydroxide with concentration of 1.5 mol/L, sodium hydroxide solution at a dripping rate of 7.7 mL/min, and hydrogen peroxide and acid leaching solution in a volume ratio of 1∶60, the average precipitation rates of iron and phosphorus are 99.86% and 98.23%, respectively, and the average loss of lithium is just 1.23%. Under the above-mentioned conditions, iron and phosphorus in the solution can be effectively removed and recycled in the form of iron phosphate, presenting a lower loss rate of lithium. After 5 h-heat treatment at 700 ℃, it is shown that the chemical composition of iron phosphate can meet the industrial standard.

In order to effectively predict blast-induced rock fragmentation, a distribution of normalized rock fragmentation under different conditions was obtained by performing a designed experiment on drilling and blasting of a concrete specimen, and then the rock fragmentation exceeding 40 mm was selected for study. The correlation among variables under different testing conditions was analyzed by using Spearman correlation statistics, and the initial weights and thresholds of the BP neural network were optimized by using the ant colony optimization (ACO) to construct an ACO-BP model. The model was then trained with rock fragmentation by on-site blasting, and tested. Based on the comparison of such prediction mode with BP neural network model, random forest (RF) model and extreme gradient boosting (XGboost) model, it is found that the ACO-BP model is highly reliable in predicting blast-induced rock fragmentation, presenting a root mean square error of 0.13, an average absolute error of 0.11, and a coefficient of determination of 0.92. It is concluded that this model, with higher accuracy in prediction and applicability, can accurately predict blast-induced rock fragmentation.

To investigate directional independence of multistage stress memory during progressive cyclic loading of granite under compression with a series of deflection angle, experiments were conducted on cyclic loading and unloading of granite with different deflection angles by using a self-made deflection device. The Kaiser effect (KE) and the incomplete erasion phenomenon (IEP) of the maximum stress in previous multistage cycles after progressive cyclic loading with deflection angles were explored in the experiments. Results show that both KE and IEP in granite exhibit directional independence. The directional independence of KE has a critical angle of 10° and the directional independence of IEP has a critical angle of 12°. With a deflection angle of 12°, the IEP will interfere with the memory of historical maximum stress by KE.

Thermodynamic analysis was conducted with HSC Chemistry 9.0 software for removing arsenic by sulfuration from waste acidic solution left after copper electrolysis, and it is found that H₂S could effectively make asenous acid and arsenate in the high-concentrated sulfuric acid system precipitated by sulfuration. Based on the theoretical analysis results, an experiment on arsenic removal of waste acidic solution by sulfuration was carried out to investigate the effects of sulfurizing agent dosage and reaction time on the arsenic precipitation effect by sufuration. Results show that by 30 min-sulfuration with an addition of H₂S at 0.87 times the theoretical amount, the arsenic content in waste acidic solution after precipitation process falls down to 10.68 mg/L from 6 777.52 mg/L, and the removal rates of arsenic, copper and antimony are 99.84%, 99.76% and 99.33%, respectively. The iron and nickel therein are hardly precipitated, and the mass fraction of arsenic and sulfur in the residue of the arsenic removal process are 43.21% and 44.68%, among which the arsenic in the form of arsenic sulfide is in a mass fraction of 42.33%, and S/As in the arsenic sulfide is in a ratio of 2.29. The finally obtained product is a mixture of As₂S₃ and As₂S₅. It is shown that the thermodynamic analysis results differ slightly from the experimental results, but are still of guiding reference for experiments and practice.

Copper slag flotation tailings were taken as raw materials, and carboxymethylcellulose (CMC), bentonite, sodium silicate alone or the mixture were taken as binders to prepare copper slag pellet for reducing dust and flue gas generated during utilization of copper slag tailings. The effect of binder on balling was explored in terms of the drop numbers, compressive strength and cracking temperature of green ball, and microscopic morphology, adsorption characteristics and surface potential changes were also analyzed by scanning electron microscopy, infrared spectroscopy and Zeta potential detection. Results show that all three binders can be useful in agglomeration of copper slag tailings. When used alone, CMC, bentonite and sodium silicate are required to be added at an amount more than 0.20%, 2.0% and 2.5%, respectively. In case of CMC used in combination with bentonite or sodium silicate, bentonite or sodium silicate should be added at an amount of more than 2.0% and more than 2.5%, respectively, with the addition of CMC is at an amount of 0.1%；while with the addition of CMC at an amount of 0.15%, the addition of bentonite or sodium silicate should be more than 1.5% and more than 2.0%, respectively. With the addition of binder, the prepared pellet has more compacted structure and stronger spatial structure. It is found that copper slag tailings particles have a lower value of zeta potential, and an improved hydrophilicity, which can promote interparticle adsorption, and thus improves pellet quality.