On the Dissociation Pressure of Pyrite

For the purpose of clarifying the roasting mechanism of pyrite ore, its thermal dissociation was investigated. The equilibrium in the reduction of natural pyrite-powder with hydrogen was measured by means of the flow method. Combining the equations obtained with those for the equilibrium constant of dissociation of hydrogen sulphide gas, the equations representing the correlation of the equilibrium dissociation pressure of pyrite with temperature were derived. The decomposition temperature of pyrite was determined to be 579℃ from the equation. Basing on the above results and those of chemical and X-ray analyses with respect to the products reduced with hydrogen, the dissociation mechanism of pyrite was discussed