Copper than less-developed countries (30–40 kg per capita). The process of recycling copper is roughly the same as is used to extract copper but requires fewer steps. High-purity scrap copper is melted in a furnace and then reduced and cast into billets and ingots; lower-purity scrap is refined by electroplating in a bath of sulfuric acid. Numerous copper alloys have been formulated, many with important uses. Brass is an alloy of copper and zinc. Bronze usually refers to copper-tin alloys, but can refer to any alloy of copper such as aluminium bronze. Copper is one of the most important constituents of
Tin(II) chloride to maintain the equilibrium towards the left-hand side (using Le Chatelier's principle). Solutions of SnCl are also unstable towards oxidation by the air: This can be prevented by storing the solution over lumps of tin metal. There are many such cases where tin(II) chloride acts as a reducing agent, reducing silver and gold salts to the metal, and iron(III) salts to iron(II), for example: It also reduces copper(II) to copper(I). Solutions of tin(II) chloride can also serve simply as a source of Sn ions, which can form other tin(II) compounds via precipitation reactions. For example, reaction with sodium sulfide produces