Abstract: Reduction kinetics of Ni_3S_2 was experimen-tally studied by following the time required forcompletion of the hydrogen reduction reaction inthe presence of calcium oxide.A simple empiricalintegration equation,derived for describing the ef-fect of CaO/S molar ratio,temperature,hydrogenconcentration and the average diameter ofNi_3S_2 grains,may be shown as following:t_(X=1)=2.317×10~(-6)d_(Ni_3S_2) C_(H_2)~(-1)β~(-2.29)e~(13710/T),minThe reduction reaction is of first order with respectto hydrogen concentration,and the apparent reac-tion activation energy is 114.0 kJ/mol.A great ma-jority of metallic Ni reduced from Ni_3S_2 is distrib-uted in the products evenly.

Key words: kinetics, nickel sulphide, reduction