Effect of Additives on Thermal Decomposition of Phosphogypsum

The effect of different additives on thermal decomposition of phosphogypsum was investigated by means of a thermogravimetry coupled with a Fourier transform infra-red spectroscopy. These additives included C, CaO, Al2O3and S. The temperature of thermal decomposition of phosphogypsum is about 1100~1320°C without any additives under the background of nitrogen. The temperature of the thermal decomposition of phosphogypsum decreased obviously with the addition of CaO, C and S. No influence was found for the thermal decomposition of phosphogypsum with the addition of Al2O3. As one of evolved products from the thermal decomposition of phosphogypsum, SO2production was discussed.