Affiliation:
1. Engineering of Research Center of Metallurgical Energy Conservation and Emission Reduction, Ministry of Education Kunming China
2. Faculty of Metallurgy and Energy Engineering Kunming University of Science and Technology Kunming China
3. College of International Education, Yunnan University of Chinese Medicine Kunming China
4. Department of Ecology and Environment of Yunnan Province Kunming China
Abstract
AbstractPhosphogypsum (PG) severely pollutes the environment and is difficult to recycle. PG is primarily composed of CaSO4 · 2H2O. In this study, the characteristics of SO2 released from the solid–solid reaction between calcium sulphide (CaS) and CaSO4 were thoroughly investigated using thermodynamic calculations. Experiments were performed by tuning the molar ratio of CaS to CaSO4, reaction atmosphere (S, CH4, N2, and air), and the heating rate. As shown by the phase diagram, high reaction temperatures favour CaO stability, and the corresponding maximum SO2 equilibrium partial pressure increases. The total SO2 production significantly increased with increasing molar ratio and slightly increased when the ratio exceeded 1:3. The SO2 productions were ranked from highest to lowest as follows: S, CH4, N2, CO, and air. The total SO2 production decreased with increasing heating rate. For the reaction between CaS and CaSO4, a higher molar ratio of CaS to CaSO4 no less than 1:3, both S and CH4 reductive atmospheres, and a lower heating rate (2°C/min) favour the total SO2 emission.
Funder
China Scholarship Council
National Natural Science Foundation of China
Subject
General Chemical Engineering