Low-alloy arc furnace slag recycled for new products
Recycling and reusing products from our production is of great importance and in line with Sandvik's sustainability goals. One of these initiatives is the handling and recycling of slag from steelmaking, which has resulted in a 100% possible recycling of the electric arc furnace slag used in the manufacture of rock drill steel.
In 2018, a project was started at Sandvik Materials Technology to productize the low-alloy arc furnace slag from rock drill steel production. Today, we can use the slag for new products developed to obtain desirable properties such as high stability, durability, toughness, and friction. The slag is formed into concrete blocks which are currently used as barriers and for material storage spaces. The great feature of the concrete blocks is their geometry, which gives them the appearance of LEGO® pieces. This means that no binder, like cement, is required, and thus temporary structures can be easily built and dismantled. The main user of the concrete blocks today is the raw material yard in Sandviken, Sweden.
Low-alloy slag residue from rock drill steel is also being tested as a slag asphalt component on the Sandviken site. Slag asphalt is a widely accepted product as it has higher torsional strength than regular asphalt and properties, which are well suited in places with high torsional loads, making it ideal for the raw material yard.
Slag is an active component in metallurgical processes and is a tool to give the steel its desired properties that are governed by the chemical composition. The composition, function, and quantity of the slag depends on the raw materials used, the process in which the slag is used, and the type of steel produced. Slag also acts as an insulating layer on the steel melt in the arc furnace, protects the melt from contact with air, and prevents energy loss.