硫砒鉄鉱と黄鉄鉱によるAs₂S₂の生成反応について

抄録

Since most arsenical ores contain both arsenopyrite and pyrite, the mutual reaction between FeAsS and FeS₂ has been investigated with the use of thermogravimetric method and differential thermal analysis in both vacuum and nitrogen atmosphere.
The reaction temperature was measured by quarz spring balance in both vacuum and nitrogen atmosphere, and weight decrease was found to begin at about 550°C in N₂ and 500°C in vacuo respectively. Further experiments using thermal differential analysis gave the reaction temperature of 560°C in N₂ atmosphere.
The resulted residue was detormined to be pyrrhotite (FeS) by X-ray and chemical analysis, and the sublimate product was As₂S₂ with excess As. This arsenic disulfide gave a distinct X-ray-diffraction pattern which was not listed in the A. S. T. M. data file and Hanawalt table.
The reaction velocity was also measured at the temperature range 550°C, -650°C using the mixture of mole ratio FeAsS/FeS₂=1.0. It was found that the reaction velocity shciwed good agreement with Jander-equation, from which the activation energy of 94.8kcal in N₂ atmosphere and 83.2kcal in vacuum was derived.