Leaching of enargite in H2SO4–NaCl–O2 media

This paper discusses the leaching of enargite (Cu3AsS4) in sulfuric acid–sodium chloride solution using oxygen as oxidant at atmospheric pressure. The dissolution of arsenic from enargite in this medium proceeds with elemental sulfur as a reaction product according to:2Cu3AsS4 + 6H2SO4 + 5.5O2 → 6CuSO4 + 2H3AsO4 + 8S° + 3H2O ssolution rate of arsenic was found to be very slow. About 6% of arsenic was dissolved in 7 h of leaching at 100 °C in a solution containing 0.25 M H2SO4 and 1.5 M NaCl under a flow of oxygen of 0.3 l/min. netics of arsenic dissolution is well represented by a shrinking core model for spherical particles controlled by surface reaction. An apparent energy of activation of 65 kJ/mol was obtained for the temperature range 80 to 100 °C.