hydrometallurgy

—hydrometallurgical, adj.

/huy'dreuh met"l err'jee/, n.

the technique or process of extracting metals at ordinary temperatures by leaching ore with liquid solvents.

[1885-90; HYDRO-¹ + METALLURGY]

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Extraction of metal from ore by dissolving the metal (as one of its salts) and then recovering it from the solution.

The operations usually involved are leaching (dissolving in water), commonly with additional agents; separating the waste and purifying the leach solution; and precipitating the metal or one of its pure compounds from the leach solution by chemical or electrolytic means. Though hydrometallurgy originated in the 16th century, its principal development took place in the 20th century. The development of ion exchange, solvent extraction, and other processes now permits more than 70 metallic elements to be produced by hydrometallurgy, including most gold, much silver, and large tonnages of copper and zinc.

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▪ science

      extraction of metal from ore by preparing an aqueous solution of a salt of the metal and recovering the metal from the solution. The operations usually involved are leaching, or dissolution of the metal or metal compound in water, commonly with additional agents; separation of the waste and purification of the leach solution; and the precipitation of the metal or one of its pure compounds from the leach solution by chemical or electrolytic means. The most common leaching agent is dilute sulfuric acid.

      Hydrometallurgy originated in the 16th century, but its principal development took place in the 20th century, stimulated partly by the desire to extract gold from low-grade ores. The development of ion exchange, solvent extraction, and other processes has led to an extremely broad range of applications of hydrometallurgy, now used to produce more than 70 metallic elements. Besides most gold and much silver, large tonnages of copper and zinc are produced by hydrometallurgy.

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