Tin concentrate usually contains the following valuable metals: tin, lead, arsenic, zinc, copper, indium, silver, cadmium and bismuth. Some tin concentrates also contain metals such as tantalum, niobium and tungsten.
Recovery of valuable metals in tin smelting process
In the process of electrolytic refining of solder, lead becomes lead chloride precipitate, which remains in anode mud together with insoluble antimony, arsenic, bismuth, copper and silver, while iron and indium are dissolved in electrolyte. When casting cathode tin, the entrained electrolyte also evaporates and concentrates and floats on the tin liquid, which is called "oil head". "Oil head" contains indium and tin, which can be recovered by solvent extraction. Anode mud is treated by chlorination distillation, and the generated tin dichloride gas is condensed and returned to be used as electrolyte; The crude lead left in the chlorination tank is refined by electrolysis to obtain electric lead, and tin, bismuth and silver can be recovered from lead anode mud. ?
Reverberatory furnace dust returns, carries out secondary reduction smelting, reduces tin and lead to metals, and zinc, indium, cadmium and germanium are enriched in the secondary dust and then recovered from it. After roasting, the precipitated slag returns to smelting, and white arsenic is distilled from the flue gas obtained by roasting. Copper concentrate and fine tin products were obtained by flotation to remove copper slag. Copper concentrate is oxidized and roasted, leached by sulfuric acid, and concentrated and crystallized to produce crystalline copper sulfate. Some tin mines in China recover tantalum, niobium and tungsten from tin smelting slag.