Slag is a byproduct formed during the smelting of metal ores, particularly in the extraction of iron and copper. It consists of various impurities, such as silica, alumina, and metal oxides, that separate from the desired metal during the heating process. Slag is typically a glassy, solid material that can vary in color and composition depending on the ore and the smelting conditions. In addition to its role in metallurgy, slag has practical applications. It can be used in construction as a substitute for aggregate in concrete, as well as in road building and as a soil amendment. Recycling slag helps reduce waste and promotes sustainability in industrial processes.