The purpose of this study was to investigate the effects of metal oxides and smelting dust on the formation of sulfur trioxide during copper, lead, zinc smelting process and flue. Focusing on the effects of SO₂ concentration, O₂ concentration, and temperature on SO₂ oxidation conversion rate under homogeneous test conditions, and under various metal oxide oxidation conditions, further in dust (mainly electric dust removal ash in copper, lead, zinc smelting process), which were studied by single factor experiment test. The results showed that the effect of heterogeneous catalytic oxidation on SO₂ conversion rate is much greater than that of pure gas phase oxidation. The addition of five pure metal oxides such as Fe₂O₃, CuO, Al₂O₃, ZnO, and CaO obviously promoted the SO₂ conversion rate under different conditions. At different temperatures, the ability of metal oxides to promote SO₂ conversion is ranked: Fe₂O₃ > CuO > CaO > ZnO > Al₂O₃. The catalytic oxidation of copper, lead, and zinc smelting dust to SO₂ conversion rate was studied, and the conclusion was drawn that the metal oxides that promoted SO₂ conversion rate in copper smelting dust were Fe₂O₃, Al₂O₃, ZnO, CaO, and the main substance was Fe₂O₃; the metal oxides that promoted SO₂ conversion in zinc smelting dust were Fe₂O₃, Al₂O₃, ZnO, CaO, CuO, and the main substances were Fe₂O₃ and ZnO; the metal oxides that promoted SO₂ conversion rate in lead smelting dust were Fe₂O₃. Whether metal oxides or copper, zinc, lead smelting dust in the experiment, Fe₂O₃ displayed the strongest catalytic oxidation capacity.

The microstructure of alloys is an important factor that affects their application. In this work, the Ag–1.5Cu–1.0Y alloys were prepared by the permanent magnet stirring method at different rates. The secondary dendrite arm spacing, dendritic segregation, density, microhardness, electrical resistivity, and sulfuration corrosion resistance were analyzed to investigate the effects of different rotation speeds on the microstructures and properties of the Ag–1.5Cu–1.0Y alloy. The results showed that the primary dendrite was refined and the secondary dendrite arm spacing decreased with the increase in the stirring rate of the permanent magnets. The Ag–1.5Cu–1.0Y alloys prepared with a 900 r/min stirring rate had the largest microhardness, relatively high density, and the best sulfuration corrosion resistance. However, the stirring rate had little effect on the electrical resistivity of the Ag–1.5Cu–1.0Y alloys. To sum up, the Ag–1.5Cu–1.0Y alloy had the best comprehensive properties when the permanent magnet stirring rate was 900 r/min, including the most refined dendrites, relatively high density, the largest microhardness, and the best sulfuration corrosion resistance. The study of the effects of permanent magnet stirring speed on the microstructures and properties of the Ag–1.5Cu–1.0Y alloy provides an experimental basis for future alloy casting optimization and property improvement of silver-based alloys.

The strong contamination of the interface is the main problem that results in low flotation efficiency of sphalerite in cyanide tailings. However, the consumption of cyanide and dissolved oxygen, as well as the concentration of ions including Zn²⁺ and SCN⁻ in the leaching solution, decreased with the use of ceramic ball medium. The conclusions obtained from SEM–EDS indicated that the use of ceramic ball medium avoided the excessive surface oxidation caused by the galvanic couple actions between the iron ball medium and the sphalerite. XPS analysis also proved that the chemical environment on the surface of sphalerite was optimized by porcelain ball medium compared with iron ball medium, avoiding the formation of Fe–OOH and Fe–O hydrophilic substances, especially [Fe(CN)₆]³⁻, thus increasing the adsorption of the collector on the surface of sphalerite. Therefore, grinding with ceramic ball medium exhibited excellent performance in terms of the cyanide process, which was approximately 5–10% higher than that obtained by grinding with iron ball media in the flotation test.

The mineral processing of a low-grade tungsten-molybdenum ore (LGTMO) was investigated to assess the potential of recovering molybdenum (Mo) and tungsten (W). Techniques such as Polarizing Microscope (PM), Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS), Mineral Liberation Analysis (MLA), and Advanced Mineral Identification and Characterization System (AMICS) were employed. The recoverable metals in the ore are Mo (0.158% ± 0.03%) and W (0.076% ± 0.02%). Mo exists in two forms: 63.30% as molybdenite and 36.7% as powellite (CaMo_xW_1−xO₄). W is present as 75.26% scheelite and 24.74% powellite. The complete dissociation rates of molybdenite and scheelite-powellite are 27.14% and 88.87%, respectively. Particles of scheelite-powellite with a diameter less than 10 µm account for 34.61%, while molybdenite particles with a diameter below 10 µm make up 72.73%. Scheelite-powellite is mainly associated with olivine and dolomite, while molybdenite is mainly associated with pyroxene, calcite, and hornblende. Based on the process mineralogy, the mineralogical factors influencing the flotation recovery of molybdenite and scheelite-powellite were analyzed. Finally, a complete hydrometallurgical leaching test was carried out. The optimal experimental conditions are as follows: liquid-solid ratio of 6 mL/g, KMnO₄ concentration of 0.015 mol/L, Na₂CO₃ concentration of 0.12 mol/L, NaHCO₃ concentration of 0.024 mol/L, leaching time of 4 h, and leaching temperature of 85 °C. Under these conditions, the leaching efficiencies of Mo and W reach 79.23% and 41.41%, respectively. This study presents a novel approach for the recovery of refractory W and Mo resources in LGTMO while simultaneously providing a theoretical basis for the high-efficiency utilization of these resources.