Arsenic leaching from a gold bearing enargite flotation concentrate

The high arsenic content of the flotation concentrate obtained from a gold-bearing enargite ore for pyrometallurgical processing strongly diminishes its market value. An investigation has been carried out for selectively leaching arsenic from enargite–luzonite minerals using alkaline Na2S solutions. By suitably adjusting the main reaction conditions almost 98% arsenic was leached, as well as part of the gold, particularly with high Na2S concentrations. Copper was not lost from the solid phase in which the enargite is converted into a new species with the chemical formula Cu1.5S.