Sulaminen

Sulaminen is the process of heating a solid material, such as a metal or mineral, to its melting point to form a liquid. In metallurgy, sulaminen is used to separate metal from impurities, to produce alloys, or to shape material by casting. The change from solid to liquid occurs when the absorbed heat overcomes the material’s lattice energy, and a portion of the heat is used as latent heat of fusion, which does not raise temperature until melting is complete.

A substance’s melting behavior depends on composition. Pure metals have a defined melting point, while impure metals or alloys may melt over a temperature range or at a lower eutectic temperature. The process requires appropriate containment and temperature control, often achieved with furnaces, induction furnaces, or crucibles in resistance heating, sometimes in a controlled atmosphere to prevent oxidation.

In industrial practice, sulaminen enables casting and forming: liquid metal can fill molds, be poured into ingots, or refined to produce alloys with desired properties. It is also central to metal recycling, where recovered metals are melted to separate and purify them for reuse. Smelting, a related term, denotes the extraction of metal from ore via reduction or smelting agents; melting is a broader term covering any phase change to liquid, including refining and alloying steps.

Common examples include iron and steel production, aluminum or copper smelting, and the casting of gold or silver into jewelry. Melting points for reference: iron ~1538°C, aluminum ~660°C, copper ~1085°C. Safety considerations include high temperatures, volatile fumes, and energy use, with slag formation as a by-product.