Abstract: The anodic behavior of synthetic nickel sulfides in sulfuric acid solutions was studied.When the anodes of Ni_3S_2 ,Ni_7S_6 and NiS are actively dissolved respectively,a solid layer forms on the electrode surface with its nature and composition depending on the potentials applied. Based on the electrochemical phenomena,phase and elemental compositions of the solid layer formed on the electrode surface were determined.The apparent number of electrons transfer- red during dissolution of Ni~(2+)was also measured.It can be considered that there are three parallel reactions ocurred on the electrode:the reaction with formation of HSO_4~- or SO_4~(2-), the reaction with formation of sulfides as intermediates and the reaction of Jorming elemental sulfur.With NiS_2 as an anode,formation of SO_4~(2-)or HSO_4~- can be considered as the only re- action occurred on the electrode.

Key words: nickel sulfide, anodic dissolution, electrochemical behavior