smeltenthalpie

Smeltenthalpie is not a standard term in English thermodynamics. In some contexts it is used to refer to the enthalpy of fusion (Schmelzenthalpie in German), the heat required to melt a solid at its melting point. In industrial metallurgy, the phrase can also describe the overall enthalpy change associated with a smelting process, i.e., the chemical reduction of ore to yield metal, including accompanying reactions and heat transfer. Because the term is not uniquely defined, its meaning depends on the context.

Enthalpy of fusion, or fusion enthalpy, is the enthalpy change involved when a solid at its melting point becomes a liquid at the same temperature. It is a material constant at a given pressure, typically given in kilojoules per mole or per kilogram. The process is endothermic, requiring energy input to overcome lattice forces. For example, ice melts at 0 °C with a fusion enthalpy of about 6.01 kJ/mol. Values vary widely among materials and generally do not depend strongly on pressure near standard conditions.

Smelting enthalpy, in an industrial sense, refers to the heat changes associated with smelting reactions used to extract metals from their ores. This includes reduction processes, oxide formation, slag interactions, and the heat required to maintain high operating temperatures. Unlike the fusion enthalpy of a pure substance, smelting enthalpies depend on ore composition, fluxes, reducing agents, temperature, and reactor design. Consequently, there is no single universal value. Engineers determine relevant enthalpies for energy balances, furnace design, and process optimization by using standard enthalpies of reaction for the involved steps and real-time heat accounting.

See also: thermochemistry, enthalpy, latent heat, phase transitions, metallurgical processes.