CO2 capture and process reinforcement by hydrolysate of phosphogypsum decomposition products

In this work, we propose a novel, effective, energy efficient technology to reduce CO 2 emissions and fully use the calcium in the solid waste by-product phosphogypsum (PG), by capturing CO 2 from the PG decomposition product’s hydrolysis solution. Experiments were conducted to investigate the technical feasibility and the influence of temperature and CO 2 partial pressure on CO 2 capture, as well as CO 2 loading on CO 2 sorption capacity. The results showed that > 90 % of the total calcium ions in the solution were converted into calcium carbonate (CaCO 3 ). Furthermore, a decrease in temperature and an increase in CO 2 partial pressure improved CO 2 uptake, with the latter having a greater effect on CO 2 capture capacity than the former. Moreover, kinetic analysis demonstrated that a higher temperature and CO 2 partial pressure increased the absorption rate; and showed that the CO 2 absorption rate is highly affected by the CO 2 loading levels. The thermodynamic analysis indicated that CO 2 absorption heat significantly declined as a function of increasing CO 2 loading. CaO from the calcination of carbonate was added to the hydrolysis solution and significantly enhanced its CO 2 capture ability. Thus, the hydrolyate of PG decomposition products in combination with CaO reinforcement may be a promising method for CO 2 capture.