Leaching of sulfide copper ore in a NaCl–H2SO4–O2 media with acid pre-treatment

A study was made of the leaching of a sulfide copper ore in a NaCl–H2SO4–O2 media after pre-treatment by agglomeration with H2SO4(conc) and NaCl. The leaching variables evaluated included the amount of NaCl to be employed, the percentage of solids in the leaching solution, particle size of the raw mineral to be leached, and the preferable method of agitation in the leaching system. Mineralogical characterization of the material to be leached included analysis of the raw ore and of the leached ore residue using reflected-light microscopy, X-ray diffraction, and scanning electron microscopy. The soluble species included djurleite and digenite. The most important parameters in the leaching process proved to be particle size and type of agitation. A total percentage of copper extraction of 70% was achieved using mechanical stirring, which increased to 78% when using compressed air agitation. The best extraction of the copper was achieved when leaching with 3 g/L of chloride, room temperature of 20 °C, and when all particles were < 1.65 mm in diameter.