A kind of low-impurity lead electrolyte was prepared with lead ingots, fluorosilicic acid, hydrogen peroxide, bone glue, and β-naphthol as raw materials, and then was used in an experimental research on 14 consecutive cycles of electrolysis to produce refined lead. It is shown that the initial power consumption of lead electrolysis was 52.37 kW·h/t, and 6N high-purity lead was produced in the first two cycles; as the cyclic electrolysis process proceeded, the impurity content and lead ion content in the electrolyte gradually increased, while the mass concentration of fluorosilicic acid gradually decreased, resulting in an increase in the impurity content of precipitated lead. Therefore, the content of Cu, Ag, Fe, Al and other impurities in the precipitated lead all gradually increased after two cycles of electrolysis, and the precipitated lead met the standard for 5N but did not meet the standard for 6N high-purity lead. Furthermore, the power consumption also gradually increased, but remained at a low level of 50 kW·h/t to 70 kW·h/t for each cycle.

A method of selective adsorption and recovery of gold from waste thiourea liquid with biomass-based adsorbent prepared from phyllostachys pubescens was proposed. The charcoal, after being activated in H₂O-CO₂ atmosphere, has more nanopores with smaller size on its surface, compared to being activated by CO₂ alone, which greatly increases the specific surface area of the adsorbent material. Based on exploration of the effects of factors, including type of adsorbent material, pH value, adsorbent dosage, adsorption temperature, and adsorption time, on the adsorption of gold in waste thiourea liquid, the appropriate adsorption conditions were obtained as follows: pH of 6, adsorbent dosage of 8 g/L, adsorption temperature of 25 ℃, and adsorption time of 3.5 h. It is found that activation in H₂O-CO₂ can bring the activated carbon with better adsorption effect, and the removal rate of gold from waste thiourea liquid by adsorption can exceed 96%. The adsorption isothermal model is used to fit the process of gold adsorption from waste thiourea liquid by the carbon activated in H₂O-CO₂ atmosphere, and the results show that such gold adsorption process follows Freundlich model and is a physical adsorption process.

For discussing rational sequence of drift stoping by cemented backfilling under complex stress conditions, with No.2 mine of Jinchuan Group as an example, a three-dimensional numerical model was constructed with a numerical simulation software, and was then used to analyze the stress field, displacement field and plastic failure zone in drift stoping with different sequences. On this basis, the drift stoping sequence, after optimization by adopting a combined weighting and fuzzy comprehensive evaluation, was then adopted in an on-site industrial experiment. The results show that both mining sequence by overhand or underhand stoping and drift stoping with different spatial sequence can bring a certain influence to the maximum principal stress, maximum tensile stress, vertical displacement, plastic failure zone, as well as the maximum principal stress and vertical displacement in the next stope nearby; mining sequence of underhand stoping followed by overhand stoping, or firstly drift stoping of vertical ore mass, can make the overall mining with higher safety. The on-site experiment with such mining sequence presents better effect. It is concluded that this research can provide some reference in the design and optimization of mining sequence for drift stoping by cemented backfilling under complex stress conditions.

Red mud was pre-treated with process of reduction roasting followed by magnetic separation, and the obtained non-magnetic material was calcined and then dissolved in hydrochloric acid. After that, it was filtered after addition of saturated sodium meta-aluminate polymerizing agent, and then matured to prepare polymeric aluminum chloride (PAC) base liquid, which was used in a purification test. With PAC-base liquid and manganese-containing wastewater in a volume ratio of 1∶120, stirring speed of 140 r/min, pH of 8, reaction temperature of 30 ℃, and addition of polyacrylamide (PAM) at an amount of 20 mg/L, the manganese mass concentration in the wastewater reduced from 325.3 mg/L to 1.5 mg/L after 5 hours of settlement, showing manganese removal rate up to 99.5%. It is shown that the manganese mass concentration in the purified liquid can meet class Ⅰ limit in the national discharge standard.

TiO₂ was coated on the surface of LiMn₂O₄ by thermal decomposition of titanate coupling agent, and the effects of coating treatment on the structure and electrochemical performance of LiMn₂O₄, as well as material structure in the cycling were all explored. The results show that TiO₂ can be uniformly coated on the surface of the LiMn₂O₄ by thermal decomposition of titanate coupling agent at 550 ℃. Surface coating does not change the crystal structure of LiMn₂O₄, but obviously improves its electrochemical performance, especially high temperature rate performance and cycle performance. At 55 ℃, LiMn₂O₄ with TiO₂ coating delivers a specific capacity of 75.34 mAh/g at 5C, which is higher than that without coating (43.05 mAh/g). After 150 cycles, the capacity retention rate of the material with TiO₂ coating and without coating is 77.27% and 62.85%, respectively. The improvement of electrochemical performance is attributed to reduction of Mn dissolution in the cathode material by TiO₂ coating, which thus inhibits the change of crystal structure during cycling process, reduces the electrode polarization and charge transfer impedance, as well as improves the charge-discharge reversibility of the material and the Li⁺ diffusion.

With the coal tailings from the flotation process of a coking coal preparation plant in Guizhou as the research object, the effects of four kinds of frother including methyl isobutyl methanol (MIBC), sec-octyl alcohol, terpenic oil and n-pentanol on the flotation performance of coal tailings were investigated. The test shows that the flotation indices of MIBC frother were better than those of the other three frothers with the similar dosage. A flotation process consisting of one stage of roughing, one stage of cleaning and one stage of scavenging was adopted to treat the raw coal with the ash content of 56.90%, and with dosages of kerosene and MIBC respectively at 1 000 g/t and 350 g/t, a qualified coking coal with the ash content of 11.47% and the yield of 32.03% can be produced. The results of foaming ability and foam stability measured by inflation method show that the foaming ability and foam stability of terpenic oil are the strongest, while those indices of n-pentanol are relatively weak, and those of MIBC and sec-octyl alcohol moderate. The characterization of the adhesion process between bubbles and coal particles under the action of different frothers analyzed with bubble-particle encapsulation angle and induction time measuring instrument suggests that MIBC can enhance coal-carrying capacity of bubbles, shorten particle-bubble induction time, thus bringing improved flotation effect.

An experimental study was carried out for adsorption of ammonia nitride and copper ions in electroplating wastewater by fly ash-based zeolite. Results show that the proper conditions for adsorption of copper ions by fly ash-based zeolite include pH of 8, initial mass concentration of 200 mg/L for copper ions in the solution, adsorption time of 0.45 h, and temperature of 200 ℃; the proper conditions for adsorption of ammonia nitride by fly ash-based zeolite include addition of 8 g/L fly ash-based zeolite, pH of 8, adsorption time of 0.60 h, and initial mass concentration of 150 mg/L for ammonia nitride in the solution. It is found that the adsorption of copper ions by fly ash-based zeolites is a physical adsorption process, and the adsorption of ammonia nitride by fly ash-based zeolites is a combination of ion exchange and physical adsorption.

A cathode material (NaNi_0.5Mn_0.5O₂) for sodium-ion batteries was synthesized by adopting solid-state, co-precipitation and sol-gel methods, and the effects of synthesis methods on crystal structure, microscopic morphology and electrochemical performance of the cathode material were also explored. The results show that the materials synthesized respectively by those three methods all have O3-type structure, but exhibit different morphology. The cathode material synthesized by solid-state method has a special layered structure, which is conducive to sodium ion de-intercalation. The cathode materials synthesized by solid-state, co-precipitation and sol-gel methods, respectively, deliver an initial specific discharge capacity of 96.1 mAh/g, 92.8 mAh/g and 92.3 mAh/g at 0.1C, with retention rate of 64.3%, 46.5% and 36.5% respectively after 100 cycles at 0.5C. It is concluded that the solid-state synthesis is an appropriate method.

An overview of progress in the research on anode materials of lithium-ion batteries based on vanadium-based compounds (including vanadium oxide, vanadate, vanadate phosphate and oxide-free vanadium-based compounds) is presented. Furthermore, based on the analysis of relationship among modification method and structure of material and electrochemical performance, it is proposed that vanadium-based anode materials for lithium-ion batteries shall become the trend in the future research.

Lithium sulfide was prepared by solid phase syntheses, with lithium metal as the lithium source, sulfur powder as the sulfur source, and lithium nitride as the additive. Thermodynamic analysis results show that lithium nitride can promote the reaction of lithium metal with sulfur powder to synthesize lithium sulfide; Li₃N firstly reacts with sulfur powder to release N₂, leading to holes formed on the molten lithium metal sheet and the contact area between lithium metal and sulfur powder further expanded. Thus a loose and porous skeleton structure is formed, which is conducive to subsequent crushing and can reduce the risk of secondary reactions in the following ball milling process. With Li∶S∶Li₃N=2∶2∶0.4 (molar ratio), crude lithium sulfide can be obtained after 8 hours reaction at 100 ℃. It is then subjected to calcination, impurity removal and ball milling processes, and a kind of lithium sulfide products with purity greater than 99.95% and particle size less than 15 μm can be obtained, which can be used in EV. This method provides a new idea for industrial production of lithium sulfide products.