Residual Products in the Steel Industry Used for Briquetting

Sammanfattning: This report looks at the implementation of briquetting in the Swedish steel industry. Briquetting is a process in which residual products are mixed and compressed into a brick-like body in order to be added to the melt in a furnace. This report investigates the type of materials commonly used in briquetting as of today. As the steel industry is moving towards an increasingly circular production process, some of the steel production will transition from blast furnaces towards electric arc furnaces. The transition process would include a change in the briquetting facilities and the residual products used in briquettes. This in turn poses a series of challenges since briquettes have different requirements depending on the type of furnace they are used in, such as material contents and mechanical requirements. In order to investigate these issues, a number of scientific texts and reports were reviewed along with a field study to SSAB: s briquetting facility in Oxelösund to provide essential information for the report. This study focuses on the difference in requirements for briquettes used in blast furnaces and electric arc furnaces. The literature review was conducted to determine how briquetting facilities previously used for blast furnaces can be transitioned in order to create briquettes for electric arc furnaces. From mapping the by-products and looking at their iron content and carbon content, it could be concluded that some by-products will not be relevant in briquettes for electric arc furnaces due to the different material requirements. These include materials with a high carbon content and a low iron content, such as CTC-filter dust, smelting emissions and ore- / coal overspill. The mechanical requirements were investigated in respect to binders and briquetting techniques. The literature review revealed that cement was exclusively used in Swedish steel plants for briquetting mainly due to the added strength of the briquette. It was concluded that the mechanical requirements of briquettes used for electric arc furnaces were lower in comparison to blast furnaces.