Coal slag is a byproduct created during the combustion of coal in power plants. It consists of the non-combustible materials that remain after the coal has burned, including minerals and metals. This material is often used in various applications, such as construction, road building, and as an abrasive in sandblasting. Due to its durability and resistance to weathering, coal slag is also utilized in the production of concrete and as a lightweight aggregate. Additionally, it can be found in some types of industrial filters and as a component in certain types of fertilizers, contributing to its versatility in different industries.