Abstract

It is well known that the Chilean mining industry is facing a shortage of water resources for the sustainable operation of not only existing plants but also of future projects. In addition, the depletion of oxide ores and those containing secondary sulfide copper will leave chalcopyrite ores as the main source of copper for future plants. This paper reports a study on the dissolution kinetics of finely ground copper oxide ore and chalcopyrite concentrate leached in shaking flasks and agitated reactors. It has been demonstrated that enhanced rates of dissolution of copper from chalcopyrite concentrate and copper oxide ore can be achieved at moderate temperatures using saline solutions. The use of sea water and discard brine do also not have any negative effect on the dissolution of finely ground copper oxide ore, achieving 98% of dissolution in shaking flasks. Shake flasks tests for chalcopyrite concentrate at ambient temperature didn't exceed 4% of copper extraction in any of the tests with seawater, discard brine and distilled water with 20 g/L of Cl-. This situation was remedied by increasing the temperature to 50°C, achieving extractions above 90%. This can be explained by the higher content of chloride ions, which can form copper complexes in solution that improve the dissolution of copper and a favorable effect of temperature. The use of discard brine and sea water as a water source could therefore eventually become a feasible option for the copper industry.