Mechanism of CO₂ Capture Technology Based on the Phosphogypsum Reduction Thermal Decomposition Process

Abstract

CO 2 emission all over the world is constantly on the rise. In recent years, CO 2 capture technology has been improved and innovated. Phosphogypsum (PG) is a solid product of industrial solid waste with an increasing annual accumulation. The research of this paper has carried out thermal decomposition of phosphogypsum under the reduction atmosphere to produce byproduct CaS and mineralization capture of CO 2 in a gas–liquid–solid three-phase fluidized bed reactor. Results show that the fluidized bed is more effective and can effectually shorten the reaction time. Meanwhile, different liquid–solid (L/S) ratios, temperatures, and pressures have been researched to study the theory of CO 2 capture by phosphogypsum. It has been found that the lower the L/S ratio is, the higher the CO 2 capture capacity is. At the same time, theoretical calculations show that high temperature promotes the decomposition of CaCO 3, thereby inhibiting the capture of CO 2, so the whole carbonation process is operated under ambient temperature and pressure. Meanwhile, this paper discusses the calcium migration path and migration mode from the decomposition of PG to the mineralization of CO 2, proposes a new idea of CO 2 capture, and makes a certain contribution to PG resource utilization.