Study on the Effect of the Activity of Anthracite on the Decomposition of Phosphogypsum

Abstract

In this paper, a thermogravimetric analyzer with Fourier transform infrared spectroscopy (TG-FTIR), pyrolysis device and gas chromatography (Py-GC), and kinetic models were used to study the effect of anthracite with different activities on the decomposition of phosphogypsum (PG) and the reaction mechanism was analyzed. The results show that the decomposition rate of PG is affected by the CO partial pressure and the thickness of the decomposition product layer, and the high-activity anthracite has a high decomposition rate of PG. It mainly contains CO, CO2, and SO2 in the decomposition process, while the solid products are mainly CaS, CaO, and Ca2SiO4. According to the kinetic calculation results at 800–1100 °C, it can be divided into three stages, namely, the one-dimensional diffusion model based on the solid–solid reaction, the two-dimensional diffusion based on the gas–solid reaction model, and the nucleation and growth model of CaO.