ReAK: Reduction of arsenic in copper concentrates
CLIENT II – Joint project of the Federal Ministry of Education and Research

Country / Region: Chile

Begin of project: September 1, 2019

End of project: August 31, 2022

Status of project: January 23, 2020

Element distributions in enargite obtained with electron microprobe Source: BGR

Chile has the world's largest economically exploitable copper deposits. With 27 % of global production, Chile is the largest copper producer and the largest copper exporter in the world. In Chile copper is mostly found in sulfide ores, especially in chalcopyrite (CuFeS₂), bornite (Cu₅FeS₄) and chalcocite (Cu₂S). The continual exploitation of ore reserves leads to the necessity of mining ores from deeper parts of deposits, often with increasing mineralogical complexity. Consequently, copper ores containing arsenic, such as tennantite (Cu₁₂As₄S₁₃) and enargite (Cu₃AsS₄), are increasingly being mined. Since highly toxic arsenic poses a threat not only to human health but also to the entire ecosystem, some countries introduced arsenic limits for imported copper concentrates. In order to comply with those limits, arsenic-rich concentrates are currently being diluted with arsenic-poor concentrates. However, this strategy will not remain feasible in the long term due to steadily increasing arsenic levels.
The Project “ReAK – Reduction of arsenic in copper concentrates” is funded by the Federal Ministry of Education and Research as part of its funding program "CLIENT II". The objective of the project is the optimization and further development of existing processes and establishment of new technologies to reduce arsenic in copper concentrates. For this purpose, various approaches are investigated and improved such as selective flotation, partial roasting, sulfidic and microbial leaching, as well as oxidative extraction to stabilize arsenic(V)-oxide, and to develop safe disposal strategies.
Detailed knowledge of the parent rock material is necessary for the successful development and implementation of individually adapted processing methods. A changing composition of the parent rock can strongly influence the efficiency of the treatment process. In this respect, BGR is dealing with the geochemical and mineralogical characterization of parent rock, as well as intermediate and residual products from processing experiments with regard to arsenic removal. Moreover, a feasibility study for a potential sensor-based pre-separation (e.g. with LIBS, XRF and hyperspectral sensors) on conveyor belts and automatic characterization of the rock materials is being carried out.

Enargite-pyrite mineralization in Cerro de Pasco, Peru Source: BGR

Further information: http://www.reak.info/

German project partner:

1. Fraunhofer Research Institution for Materials Recycling and Resource Strategies (IWKS)
2. Federal Institute for Geosciences and Natural Resources (BGR)
3. Outotec GmbH & Co.KG (Outotec)
4. Technische Universität Bergakademie Freiberg (TUBAF)
5. EnviroChemie GmbH (EC)
6. Wismut GmbH (Wismut)
7. Aurubis AG (Aurubis)
8. Borregaard Germany GmbH (BD)
   

Chilean project partner:

1. Pontificia Universidad Católica de Chile (PUC)
2. EcoMetales
3. German-Chilean Chamber of Industry and Commerce (AHK Chile)
4. Universidad de Concepción (UdeC)
5. Universidad de Santiago de Chile (USACH)
6. Sustainable Minerals Institute International Centre of Excellence Chile (SMI-ICE)
7. Alta Ley
   

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