Application of Fly Ash from Pulp and Paper Industries as Slag Formers in Electric Arc Furnace Stainless Steel Production

Abstract

During electric arc furnace (EAF) steelmaking process, burnt lime is charged together with other slag forming materials to attain a specific basicity of the slag and to achieve purification by removing unwanted elements. Herein, fly ash (FA) containing ≈60% CaO generated from pulp/paper mills is tested to partially (15–50%) replace primary lime (PL) in pilot scale EAF trials. The obtained results show good possibilities. It is found that an increased amount of FA instead of PL reduces the required amount of FeSi (up to 3 kg t−1 of scrap) and increases the sulfur content in the final slag. As a result, the amount of required slag/ton of steel can be decreased. However, the phosphorus content in the metal is slightly increased. The replacement ratio of FA will be limited by the acceptable phosphorus level in the final steel, due to higher phosphorus content in FA from pulp and paper mills compared with that in PL. Applications of FA as slag formers can reduce the consumption of natural resources in the metallurgical processes. In addition, it can reduce the amount of wastes from pulp/paper industries sent to landfill, which is important from an environmental point of view.

Neutralization of Acidic Wastewater from a Steel Plant by Using CaO-Containing Waste Materials from Pulp and Paper Industries

“…Furthermore, it is obvious that we, the modern society, need to redirect linear material flows towards more circular flows. For instance, the possibilities to utilize secondary lime materials (fly ash and calcined lime mud) from pulp and paper production as slag formers in electric arc furnace and argon oxygen decarburization stainless steelmaking processes have been successfully tested as is described in previous publications [ 6 , 7 ].…”