The Mechanism of Thermal Decomposition for Ammonium Sulfate and Ammonium Bisulfate via Addition of Ferric Oxide

Ammonium sulfate, ammonium bisulfate and ferric oxide are mixed at a molar ratio of 8:5:13 and heated in high temperature muffle furnace or fluidized bed at different temperature. To the sample, the thermal gravimetric (TG) analysis is used, the reaction residue is analyzed by fourier transform infrared spectroscopy (FT-IR) and chemical analysis, the generated gas is qualitatively analyzed as well. The process of thermal decomposition for ammonium sulfate and ammonium bisulfate via addition of Ferric oxide has four stages-the decomposition of ammonium sulfate, the formation of ammonium ferric pyrosulfate, the decomposition of ammonium ferric pyrosulfate, and the decomposition of ferric sulfate. The ammonium ion in sample is completely decomposed at about 500°C. The decomposition ratio of sulfate ion or bisulfate ion is up to 99.8% above 800°C.