In recent years arsenic content in copper concentrates has increased along with environmental restrictions for their transport and processing. China has set a benchmark maximum of 0.5% for the arsenic content in copper concentrates and in the future it is expected that this value is going to be more restrictive. Smelting process disposes part of the arsenic as calcium arsenite which is not a stable compound and in the future changes will have to be made to dispose this arsenic as a stable compound.Under this scenery is being developed the Complex Concentrate Leaching Project (PLCC), which allows the treatment of copper concentrates with high arsenic content (>0.5%) through a high pressure (2873 kPa) and temperature (220°C) leaching process within an autoclave. Through the addition of high purity oxygen and cooling water to control the temperature is possible to dissolve over 99% of copper and arsenic compounds. Dissolved arsenic is then precipitated as ferric arsenate, which is a stable compound that passes all the environmental tests. The oxidized slurry from the autoclave is depressurized, cooled and afterwards sent to a solid/liquid separation stage generating a high copper PLS solution and an arsenical residue. The PLS is sent to a solvent extraction plant to produce copper cathodes where it is previously mixed with heap/dump PLS solutions. On the other hand, the arsenical residue is stored on a deposit or sent to a silver recovery process that will be developed in a future stage.This work describes the progress to date of the PLCC project highlighting: the laboratory and piloting tests work and principal results, process description, advantages and strengths of the project and it's insertion within the Northern District of Codelco or other companies in different countries in order to be a solution for the treatment of complex copper concentrates.
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