Reduction of Chilean copper slags: a case of waste management project

Abstract

The Chilean copper smelters are producing large amount of copper slags. These copper slags are deposited at landfills. In the present time, a huge amount of copper slags are accumulated in Chile. The main problem with landfilling is not only the land space, area which is used for copper slags deposition every year, but many environmental problems, high disposal and transport cost are associated with the landfilling of these slags. Therefore, the focus of environmental policy is now into waste minimization and recycling to minimize transport and disposal cost, saving resources as well as land space. Copper slag contains many useful metals and slag making oxides, which can be recovered and recycled by a high temperature direct reduction process. The laboratory scale tests show that by suggested high temperature direct reduction of copper slags two products can be obtained, a Fe–Cu–C alloy with precious metals content and an inert slag with low metal content. The Fe–Cu–C alloy can be used for metal production and inert slag for cement production similar to blast furnace slags. Suggested high temperature direct reduction process for copper slags treatment is commercially feasible and environmentally friendly without any solid or liquid waste.