EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

The metal manufacturing sector is responsible of producing huge amounts of solid wastes, most of them containing valuable metals. In some cases, these wastes can be recirculated again in the process, but in most of the cases they are sent to centralized treatment plants. Metallurgical processes used in these centralized plants to valorise metallic wastes and recover valuable metals such as copper, zinc or tin are far from their optimum resource efficiency. Moreover, there is still a fraction of waste that needs to be landfilled after the process.
In the context of decarbonisation to reach climate neutrality by 2050 that is at the heart of the European Green Deal, it is completely necessary to increase energy and resource efficiency of this kind of industrial processes.
H2020 funded CIRMET project is contributing to these objectives through the development of an innovative and sustainable technology to valorise metallic wastes following a zero-waste approach. This technology is based in a pyrometallurgical process that reduces complex oxides to recover high value metals using a high-power plasma-based energy source.
Despite being a very efficient heating system, this process consumes coke as reducing agent of the oxides of the waste, thus emitting fossil CO2. In order to reduce the environmental impact of the process, substituting fossil CO2 emissions by biogenic CO2 emissions, the substitution of coke by biochar is being studied within the project. This work presents the results of the experimental study carried out at lab-scale to analyse the recovery rate of metallic elements from non-ferrous metallic wastes using biochar as reducing agent. Biochar obtained through optimized torrefaction processes of two kind of woody biomasses (oak and poplar) has been mixed with different metallic wastes and tested in lab-scale furnaces to study its behaviour compared to coke with satisfactory results.