A copper-lead-zinc polymetallic sulfide ore, being characterized by complex dissemination of main minerals and intimate intergrowth of valuable minerals and gangue, was taken for study. In an experiment, the raw ore grading 0.21% Cu, 2.37% Pb and 3.01% Zn was treated with a weak-alkali process, consisting of Cu-Pb bulk flotation, Cu/Pb separation and Zn flotation. With A22 as a copper-lead bulk flotation collector, TZ01 and zinc sulphate as depressants of zinc and sulfur minerals, CZ08 as a zinc flotation collector, sodium sulfite and CMC as depressants for Cu/Pb separation, a copper concentrate grading 22.09% Cu at 70.48% recovery, a lead concentrate grading 59.48% Pb at 89.35% recovery, and a zinc concentrate grading 45.00% Zn at 86.96% recovery were yielded.

In order to effectively separate acid, arsenic and copper/zinc from smelting waste acid, a kind of simulated waste acid was taken to be treated by using electrodialysis with bipolar membrane. The effects of running time, acidity, initial concentration of arsenic and copper/zinc on the separation rate of acid, copper/zinc, and arsenic were investigated, and the process was also applied in the treatment of waste acid from copper smelting for verification. Besides, the surfaces of anion exchange membrane, cation exchange membrane and bipolar membrane in electrodialysis after long-term usage were analyzed and characterized. The results show that with the running time more than 80 min, arsenic concentration less than 9 g/L, acidity less than 5% and copper/zinc concentration less than 5 g/L, three kinds of solution respectively containing arsenic, valence metallic salt and acid were obtained. It is shown that the arsenic separation rate is more than 93%, the recovery rate of copper/zinc is more than 96%, and the recovery rate of acid is more than 97%. More than 90% of other metallic ions (such as Na, K, Mg, Ca) in waste acid are trapped in the bipolar membrane salt chamber, thus making inorganic salt ions effectively recovered from waste acid by an open circuit. After nearly two years of application, electrodialysis membrane and bipolar membrane are observed to have no obvious change in the apparent morphology, and no obvious precipitant attached on them.

The effects of different heat treatment processes on the microstructure and mechanical properties of RM80 steel were studied by means of scanning electron microscopy, Rockwell hardness tester and universal testing machine. As quenching temperature increases, carbides in RM80 steel gradually dissolve and the original austenite grains continue to grow. During tempering process, the structure of RM80 steel changes from tempered troostite to tempered sorbite, and martensite can still be observed in the structure of RM80 that is tempered after quenching at a higher temperature. After quenching at 1 150 ℃ and then three times of tempering at 550 ℃, RM80 steel finally has a good match between strength and plasticity, with a yield strength of 1 244 MPa, a tensile strength of 1 590 MPa, and an elongation of 12.0%.

With Sanguikou Lead Zinc Mine in the Inner Mongolia Autonomous Region taken for study, the influencing factors and parameter optimization for rock fragmentation by deep-hole cut blasting were explored by performing theoretical analysis, image processing and engineering tests. Firstly, in view of the problems of high fines generation rate and small fragment size on average, the factors influencing blasting fragmentation were tested and field data were collected. Also, image processing and analysis were performed for the muckpile in the test by using Split-Desktop 4.0 software. Then, the primary and secondary factors affecting blasting fragmentation were determined based on grey correlation analysis. Finally, an optimal scheme of blasting parameters was determined by using trend analysis based on actual situation of the site, and was then verified in the practical engineering test. The results show that the fines generation rate by the cut blasting in the mine is mainly affected by the delay time between rows and the borehole spacing, and the average fragment size is mainly affected by the borehole spacing and the number of rows for blasting. The optimized blasting parameters are finally determined as follows: borehole spacing of 1.2 m, row spacing of 1.5 m, burden of 0.8 m, 3 rows of boreholes, delay interval of 13 ms, 0 ms, 9 ms and 18 ms, respectively, between 4 holes, and a delay interval of 42 ms between rows. With the above-mentioned parameters, the blasting can result in the fines generation rate down by 27.19% and the average fragment size up by 62.89%.

In order to comprehensively utilize iron-containing dust and consume alkaline residue from petrochemical industry, a sintering pot test was conducted by adding iron-containing dust and the alkaline residue from petrochemical industry into raw materials for sintering. The results show that an addition of iron-containing dust and the alkaline residue from petrochemical industry can not only improve vertical sintering speed, utilization coefficient, yield rate and tumbler index, but also lead to increased content of alkali metals and Zn, as well as falling in the TFe content in the sintered ores. Thus, the sintered ore presents poor reduction performance, and poor low-temperature reduction pulverization indices. It is found that the raw material with the addition of iron-containing dust at an amount of 0.5% and the addition of alkaline residue from petrochemical industry at an amount of 0.05% can meet the requirement for feed to furnace, and also make it possible for the comprehensive utilization of iron-containing dust and consumption of alkaline residue from petrochemical industry.

316L stainless steel coatings were prepared on the surface of 304 stainless steel by using laser cladding at different scanning speed, and then metallographic microscopy, X-ray diffractometer, scanning electron microscopy and microhardness tester were adopted respectively to investigate the macroscopic morphology, phase composition, microscopic structure and microhardness for the coatings. The results showed that the 316L coating had a single-phase austenitic structure, and as the scanning speed increased, the grain size of the coating became smaller due to the reduction in the laser power density and heat input, and an increase in the cooling speed. It is found that the microhardness of the coatings is positively correlated with scanning speed, and the 316L coatings prepared by laser cladding at a scanning speed of 1 400 mm/min presents the highest microhardness of about 275HV_0.3. The improvement of the microhardness of the coating is ascribed to the effect of solid solution strengthening caused by lattice distortion combined with the effect of fine crystal strengthening. The wear test showed that the average friction coefficient of 316L coatings was significantly lower than that of 304 stainless steel substrate. And the 316L coating prepared by laser cladding at 1 400 mm/min has a friction coefficient of 0.424 and wear rate of 2.29 × 10^-6 mm³/(N·m), and is prone to abrasive wear.

Experiments on tempering at different cooling rates were conducted for annealed 30CrMnSiA steel to investigate the effect of cooling rate during tempering on the properties of tempered 30CrMnSiA steel and its microstructure evolution. The results show that the cooling rate during tempering has brought slight effect to the hardness, and a certain influence to impact properties of 30CrMnSiA steel. After tempering at 510 ℃, the 30CrMnSiA steel has its surface mainly subjected to compressive stress and the center subjected to tensile stress. A faster cooling rate during tempering will result in a higher residual stress on the surface of the sample. During the tempering process, C element mainly combines with Fe element to form Fe-C compounds, while a trace of C element, together with Cr and Si elements, forms Cr-C compounds and Si-C compounds. It is found that the rapid cooling rate has slight effect on the content and size of carbides.

The furnace slag generated from smelting of South African vanadium-titanium magnetite was taken in an experimental study by adopting direct reduction followed by melting, and then analyzed by XRD to investigate the effect of basicity on the metallurgical properties of the slag, as well as on the separation of iron from slag. Furthermore, the effect of basicity on the melting characteristics and viscosity of the slag were also explored. Results show that melting at 1 450 ℃ with the addition of carbon at an amount of 5%, the slag has its corresponding softening temperature, hemisphere temperature and flow temperature rising gradually with the increase in basicity. With the basicity ranging from 0.9 to 1.2, the melting temperature of slag increases rapidly, and the measured and calculated viscosity of slag presents a trend of an initial decrease followed by increase. When the basicity rising from 0.9 to 1.4, the diffraction peaks of pyroxene and feldspar in the slag climb to the high value and then start to fall, and the relative contents of perovskite and calcium-aluminum spinel gradually increase after an initial decrease. It is shown that the slag with basicity of 1.2 and viscosity of 0.130 Pa·s can present better performance.

Based on the technique for separation and recovery of metal ions in the leaching solution of spent lithium-ion batteries, nickel and cobalt ions were efficiently separated from manganese ions in leaching solution by selective precipitation of sulfide. The effects of pH value, addition coefficient of sodium sulfide, temperature and time for precipitation on the precipitation rates of nickel, cobalt and manganese ions were systematically investigated. The results show that the precipitation rates of nickel, cobalt, manganese and aluminum ions are 99.73%, 100%, 2.77% and 1.24%, respectively, after 6 min-precipitation at 25 ℃ with the addition of sodium sulfide at a coefficient of 1.5 and pH of 5.0. An orthogonal experiment shows that factors of addition coefficient of sodium sulfide, pH value, precipitation temperature and precipitation time have influence on the precipitation rates of nickel ions in a descending order, while the various factors of addition coefficient of sodium sulfide, precipitation temperature, pH value and precipitation time also have influence on the precipitation rates of cobalt ions in a descending order. It is found that the precipitation rates of manganese and aluminum can reach 99.77% and 6.86%, respectively, after a 12 min-precipitation at 70 ℃ with addition of sodium sulfide at a coefficient of 2.5 and pH of 6.0.

V₂O₅ thin films were prepared on FTO conductive glass substrates by electrodeposition-assisted sol-gel technique, and effects of precursor concentration on the structure, morphology and optical properties of V₂O₅ thin films were investigated. The results of XRD and XPS show that the prepared films are all V₂O₅ films, and the diffraction peaks in the XRD pattern are sharp, indicating that the films have good crystallinity. No other impurity peaks appeared in the XRD and XPS spectra, which indicated that the prepared V₂O₅ film had high purity. The results of SEM show that the surface of V₂O₅ film is uniform and compact, and mainly consists of spaced small particles. UV/VIS/NIR test results indicate that the transmittance of V₂O₅ thin film is greatly affected by the concentration of precursor, and reaches the highest of 80.18% when the concentration of precursor is 1∶100. The infrared spectrum test result shows that the infrared transmittance of V₂O₅ thin film decreases from 89.5% to 20.5%, as its semiconductor state at low temperature changes to metal state at high temperature.