Enthalpy of thermal decomposition of pyrite concentrate

Abstract

The enthalpy of thermal decomposition of pyrite concentrate (PC) in an inert atmosphere was measured by differential thermal analysis (DTA) and differential scanning calorimetry (DSC). The decomposition is a two-stage process and the enthalpy values of the overall process determined by the two methods are very close to each other: DTA, Δ H = 72.2 kJ per mol FeS 2; DSC, Δ H = 70.1 kJ per mol FeS 2. These values are quite different from the calculated standard enthalpy of FeS 2 decomposition at 1000 K, Δ H = 154.0 kJ per mol FeS 2, and the enthalpy calculated from the Clausius—Clapeyron equation with dissociation pressure data for FeS 2, Δ H = 181.9 kJ per mol FeS 2.