hydrometallurgy

hydrometallurgy

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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hydrometallurgy [¦hī·drō′med·əl‚ər·jē]

(metallurgy)

Treatment of metals and metal-containing materials by wet processes.

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Hydrometallurgy

The extraction and recovery of metals from their ores by processes in which aqueous solutions play a predominant role. Two distinct processes are involved in hydrometallurgy: putting the metal values in the ore into solution via the operation known as leaching; and recovering the metal values from solution, usually after a suitable solution purification or concentration step, or both. The scope of hydrometallurgy is quite broad and extends beyond the processing of ores to the treatment of metal concentrates, metal scrap and revert materials, and intermediate products in metallurgical processes. Hydrometallurgy enters into the production of practically all nonferrous metals and of metalloids, such as selenium and tellurium. Hydrometallurgical and pyrometallurgical processes complement each other. See Leaching, Pyrometallurgy

Hydrometallurgy occupies an important role in the production of aluminum, copper, nickel, cobalt, zinc, gold, silver, platinum, selenium, tellurium, tungsten, molybdenum, uranium, zirconium, and other metals. See Metallurgy