Recycling of minerals from secondary metallurgy residues (REM)

Purpose and goal:

The aim of the prestudy has been to increase the use of ladle slag and minimize the amount of virgin lime and dolomite used in the EAF (electric arc furnace) process. The objective has been to find a way to use the companies ladle slag in their own EAF.

The project shows that it is possible to use ladle slag as a slag former in the electric arc furnace without changing the properties of the EAF-slag. More full-scale trials are however needed to find exactly how much ladle slag can be used and what quantities of virgin slag formers, such as lime, dolomite and sand, can be replaced.

Expected results and effects:

The calculations and tests carried out indicate that it is possible to use ladle slag as a slag former in EAF without changing the properties of the EAF slag. And that, after optimization, roller press briquettes can be produced from the ladle slag. An initial trial has been carried out at Höganäs with promising results.

The result of the project *has given a first idea on how to use ladle slag as a slag former in the EAF.

*gives opportunities to reduce the emissions of CO2 as the slag can replace parts of the lime and dolomite that are used today. *can lead to a reduced amount of ladle slag to landfill. Approach and implementation:

The work has consisted of a mapping of the companies´ ladle and EAF slag, thermodynamic and mass balance calculations, lab scale melting trials and an initial briquetting test of the ladle slag using a roller press. Höganäs and Celsa have also studied how to implement the use of ladle slag in their operations.

The mapping gave good input to the calculations that were performed, which in turn contributed with knowledge to the melting tests. Höganäs´ and Celsa´s own studies were good contributions to the project.