Patent ID: 7074381

Claim:
A process for producing an ammonium polythiomolybdate or a hydrate thereof of the formula (NH 4 ) 2 Mo 3 S 13 .n H 2 O where n is 0, 1 or 2 comprising: (a) in a first reaction step, reacting, in a sealed reactor, aqueous ammonium monosulfide, elemental sulfur and molybdic oxide, with hydrogen sulfide gas being fed into the reactor until the hydrogen sulfide is no longer absorbed by the reaction mixture; and (b) in a second reaction step, heating the reaction product of the first reaction step in a sealed reactor; wherein, the concentration of ammonium monosulfide in the reaction mixture is controlled throughout the reaction such that pressure in the reactor of both steps (a) and (b) does not exceed 700 kPa (100 psig).