Di Maria, Andrea; Khoshkloo, Mohammad; Berse, Richard; Teigler, Ernst; Sand, Anders; Van Acker, Karel

Sulphidic mine residues (SMRs) are residues from the mining and extraction of metals. SMRs can still contain valuable non-ferrous metals such as Cu, Zn, Co and Ni. The H2020 project NEMO (Near-zero-waste recycling of low-grade sulphidic mining waste for critical-metal, mineral and construction raw-material production in a circular economy) investigates the valorisation of SMRs. The development of new technologies to exploit the reuse potential of SMRs (i) allows the recovery of valuable metals and minerals, (ii) reduces the need for storage facilities through the valorisation of the inert fraction as secondary construction material, (iii) reduces the adverse effects related to oxidation of sulphidic tailings and acidic mine drainage. The proposed technologies are based on bioleaching, followed by chemical precipitation. The aim is to recover metals from a pregnant leach solution and to reuse the residual mineral fraction as a component for the production of cement, aggregate and concrete. As part of NEMO, this work combines environmental and economic assessments to analyse the sustainability of the developed technologies. This approach results in a life cycle analysis (LCA) and a life cycle costing (LCC) of the proposed SMRs valorisation, based on data from the pilot-testing campaigns. The environmental analysis highlights the benefits derived from the metal recovery and the reduction or avoidance of landfill. In addition, it shows the impacts related to the bioleaching processes, which is the main environmental “hotspot” of the entire valorisation process. In parallel, the LCC analysis shows the economic potential of the technologies, based on the revenues from the sales of the recovered metals and construction materials as well as the reduced landfilling. The combination of the two analyses allows the development of more informed support for policymakers to support sustainable metal supply in Europe.