1999 Volume 78 Issue 2 Pages 99-109
The performance of chemical reaction of CaS particle under oxidizing atmosphere condition was investigated in the temperature range of 700 to 1300°C by a TG-DTA apparatus. The chemical reaction was found to be complicated process with the products of CaO, CaSO4 and the release of SO2 gas. The weight of sample changed in the following three different ways: gain, loss, and oscillation. The whole reaction process could be classified into three reaction steps: The reaction of CaS +2O2→CaSO4 took place as the weight gain in the first step.The weight loss with release of SO2 gas resulted from the reaction of CaS + 3/2O2→CaO + SO2 in the second step.The oscillation behavior in the third step can be given explanation through the decomposition and formation of calcium sulfate. The temperature range of the second step was strongly dependent on the O2 concentration of inlet gas. Higher bulk O2 condition led to the higher O2 concentration at the reaction front, so that the temperature of second step shifted to higher one. The reaction rate of CaS to CaO between 950 and 1050°C at 1% O2 was expressed as 1.1 × 1017 exp (-54847/T) s-1.