slagforming

Slagforming is a metallurgical process that involves the separation of impurities from molten metal. These impurities, along with fluxing agents, form a molten layer known as slag that floats on top of the molten metal. This slag layer serves multiple purposes, including protecting the molten metal from oxidation by the atmosphere, insulating it to maintain temperature, and facilitating the removal of dissolved impurities.

The composition of slag is dependent on the base metal being refined and the specific impurities present. Common fluxing agents include lime, silica, and alumina, which are added to lower the melting point of the impurities and encourage their dissolution into the slag phase. As the slag forms, it can absorb dissolved gases and oxides from the molten metal.

Slagforming is a critical step in the production of many metals, including iron, steel, and copper. In steelmaking, for example, slag is used to remove phosphorus and sulfur from the molten iron. The slag is periodically tapped or skimmed off the surface of the molten metal, leaving behind a purer metal. The properties of the slag, such as its viscosity and density, are important for efficient separation and are controlled by adjusting the composition of the fluxing agents. The management and disposal of slag are also important considerations in industrial processes.