Recovery of Strategic and Critical Raw Materials from intermediate products of a novel recycling process

Today’s modern society is in need of many strategic and critical raw materials. Especially Europe faces drastic scarcities regarding the supply of metals for future key-technologies. The European Commission has put together a list of critical raw materials that are of central importance for the European Union, such as indium, cobalt, and zink.¹

Many metallurgical processes generate residual materials, which are not yet being adequately recycled. These residues often contain low quantities of critical raw materials and other high value elements. Even if the concentration of the valuable elements might be low, the amount of residues can be huge and it can therefore be economically and strategically motivated to develop processes for recovering those elements. Indium is an example of one of the most critical metals on the planet, due to its wide application. Therefore, the metallurgical society, is taking comprehensive efforts to ensure the supply of this technology metal.

There is thus a need to develop economically and environmentally sustainable processes and techniques to recover these resources. In a particular pyrometallurgical process that has been studied at Montanuniversität Leoben an industrial residue from zinc industry is thermally treated whereby several valuable elements are vaporized, including indium, silver, tin, etc. via the reaction with chlorine compounds. The elements are then collected in a dust phase, consisting mainly of oxides and chlorides.

The current project is focused on developing a hydrometallurgical process to recover the valuable elements from this dust phase. For this purpose, a metallurgical process is to be developed which separates the metal chlorides into their individual components and makes them recoverable as a product.

The work will include: 

1. Calculation and mixing of a synthetic dust phase based on the chloride fractions analysed in previous experiments
2. A literature survey accompanied by thermodynamic calculations to investigate the potential for recovering the valuable elements
3. Laboratory experiments to test and verify methods for recovery of the valuable elements 
4. Evaluation of data and proposing a process for resource recovery
5. Possible study visit to the research group at Montanuniversität Leoben.

Supervisors:

Dr. K. Forsberg (KTH), examiner

Dr. Stefan Steinlechner (Montanuniversität Leoben)

Lukas Höber (Montanuniversität Leoben)

Reference:

¹ https://ec.europa.eu/growth/sectors/raw-materials/specific-interest/critical_en