Studies on the autoclave oxidation of nickel sulfides mainly consider the behavior of fused nickel sulfide, close in composition to heazlewoodite Ni₃S₂. Only a few have highlighted the kinetics of dissolution of nickel monosulfide NiS, one of the main components of various intermediate products of nickel production: anode slimes, nickel sulfide concentrate obtained by precipitation with hydrogen sulfide, and the intermediate phase of autoclave dissolution of nickel concentrate from flotation of copper nickel matte...