Synthesis of iron group metal sulfides from the elements under hydrothermal condition

Abstract

Iron group metal sulfides were synthesized from the elements under hydrothermal condition. For nickel sulfides, two kinds of nickel metal powder, coarse powder passed through 63 μm mesh and fine powder passed through 3 μm mesh, were used as the starting materials. The reaction with the coarse Ni powder gave NiS with appreciable amount of Ni, Ni3S2, and Ni9S8. Pure NiS was obtained by the reaction with the fine Ni powder at 240°C for 10 h. The lowest nickel sulfide Ni 3S2 was obtained as a single phase product of the reaction if the coarse Ni powder was used. From these results, the fine and coarse powders were found to be suitable for the syntheses of NiS and Ni 3S2, respectively. The lowest cobalt sulfide Co 9S8 was obtained almost as a single phase though the XRD pattern of the product showed some unidentified peaks. Pure Co9S 8 was obtained by washing the reaction product with HNO3. In the Fe-S system, FeS was obtained with a small amount of Fe3O 4.