Leaching of metal sulphides

Abstract

The process of the invention is for the separate recovery of elemental sulfur and residual sulfides and metal salt solution from reaction slurries obtained from leaching of metal sulfides in ores and concentrates. The process comprises directing flow of a said reaction slurry at a temperature at which sulfur is present in the liquid state and at a pressure such that flashing of vapor is avoided into a separating step comprising a substantially quiescent zone, coalescing said elemental sulfur in the substantially quiescent zone, settling coalesced sulfur together with unreacted sulfides from said quiescent zone, maintaining a velocity in said flow in said substantially quiescent zone to cause separation of said slurry into a first and a second fraction, said velocity having an upward velocity component, said first fraction containing dissolved metals and at least one material chosen from gangue materials and precipitated compounds, said at least one material having a terminal settling velocity less than said upward velocity component, and said second fraction containing coalesced liquid elemental sulfur and unreacted sulfides, and separately discharging said first and second fractions from said separating step.