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
Copper in heat exchangers introduced in 1890 for seawater service. By the 1920s, a 70% Cu-30% Ni alloy was developed for naval condensers. Soon afterwards, a 2% manganese and 2% iron copper alloy was introduced for better erosion resistance. A 90% Cu-10% Ni alloy first became available in the 1950s, initially for seawater piping. This alloy is now the most widely used copper-nickel alloy in marine heat exchangers. Today, steam, evaporator, and condenser coils are made from copper and copper alloys. These heat exchangers are used in air conditioning and refrigeration systems, industrial and central heating and cooling systems, radiators, hot water tanks, and