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 Cu_1.5S.