Hydrometallurgi

Hydrometallurgy, also known as hydrometallurgi in some languages, is a branch of extractive metallurgy that uses aqueous solutions to dissolve and recover metals from ores, concentrates, and secondary materials. The process typically involves dissolving the target metal by an appropriate leachant, then separating and recovering it from the solution through precipitation, cementation, solvent extraction, ion exchange, and electrowinning.

Leaching is the central step and can be conducted by different methods, including heap leaching, agitated tank leaching, in-situ leaching, and bioleaching. Leachants such as sulfuric acid are common for copper and uranium, cyanide is used for gold, and alkaline media are employed for some nickel-containing ores. After dissolution, the metal is recovered from the solution using methods such as solvent extraction, ion exchange, precipitation, or electro-winning to produce a refined metal product.

Hydrometallurgy is widely applied to primary metal production from low-grade or complex ores and to the treatment of secondary sources, such as spent catalysts and electronic waste, to recover valuable metals. It is particularly prominent in copper production (where solvent extraction and electrowinning are standard) and gold recovery (notably cyanide leaching). Other metals recovered by hydrometallurgy include nickel, cobalt, zinc, uranium, and certain rare earths.

Advantages of hydrometallurgy include lower energy consumption and the ability to process materials that are unsuitable for traditional high-temperature methods. Disadvantages involve chemical handling hazards, management of acidic or cyanide-bearing effluents, and potential environmental impacts from leachates and tailings. Ongoing research emphasizes bioleaching, recycling, and closed-loop water treatment to improve sustainability.