Pyrometallurgy involves high-temperature processes like roasting, smelting, and refining.
Hydrometallurgy uses water-based (aqueous) solutions to leach metals from ores.
Roasting (heating in air) is a common step in pyrometallurgy to convert sulfide ores to oxides.
Leaching is used in hydrometallurgy where a solvent dissolves the desired metal from the ore.
Copper is often extracted from low-grade ores using hydrometallurgical leaching methods.
Electrolytic refining uses electrolysis to purify metals such as copper and zinc.
Mond's process uses carbon monoxide to form volatile nickel carbonyl, which decomposes to pure nickel.
Calcination involves heating in the absence or limited supply of air, used mainly for carbonate ores.
Zone refining purifies semiconductors like Si and Ge based on differences in solubility at different temperatures.
The cyanide process is a hydrometallurgical method used for the extraction and refining of gold and silver.