Stainless Steel in Electronics Recycling : From Challenge to Resource

This thesis is conducted in collaboration with Stena Nordic Recycling Center in Halmstad. In the company´s electronics recycling process, stainless steel has long presented a challenge due to its high hardness, density similar to other metals, and elevated chromium content. In electronic waste, the most common alloy is austenitic stainless steel, and through cold working, it can exhibit magnetic properties that affect sorting options. The aim of the project is to identify a technical solution to minimize equipment wear and reduce penalty fees associated with high chromium levels. This is achieved by focusing on separating stainless steel in the process and evaluating the potential value of selling a stainless steel fraction. The work also includes identifying and locating damage on existing equipment and analyzing where in the process flow a new solution should be implemented for maximum effect. An economic analysis is developed to support decision-making regarding the implementation of the proposed solutions. The project provides solutions to both problems in the recycling process and results in two proposals. The first solution involves modifying the wet shaking tables to improve the separation of stainless steel, with the aim of reducing financial losses from penalty fees. It is also proposed to upgrade the magnetic separation process by using improved magnetic separation technology to remove stainless steel earlier in the recycling process, thereby reducing equipment wear and additional financial losses. Both solutions result in a new or increased fraction of stainless steel that boosts revenue. By upgrading the current equipment, the implemented solution will contribute to a technical and sustainable innovation by reducing costs and increasing the recycling rate.