A smelter is a facility used to convert raw metals into their pure form by melting and refining them. The process typically involves heating the metal ore or scrap to extremely high temperatures, which causes impurities to separate from the metal as they melt at lower temperatures than the metal itself. Once the impurities have been removed, the molten metal is poured into molds and allowed to cool before being processed further. Smelting can be done using a variety of methods such as pyrometallurgical or hydrometallurgical processes depending on whether it involves melting in the presence of oxygen (pyrometallurgy) or without melting but dissolving in water (hydrometallurgy).