An efficient methodology to use hydrolysate of phosphogypsum decomposition products for CO2 mineral sequestration and calcium carbonate production

Abstract

There is an urgent need to find new, improved ways to reduce CO2 emissions and treat phosphogypsum (PG) waste. This research proposes an energy-efficient methodology for the production of pure calcium carbonate and CO2 mineral sequestration (CMS) by hydrolysate of PG decomposition products. The technical feasibility of this process and the influence of process variables on CMS were investigated using online experiments. Pure calcium carbonate was obtained by CO2 separation and mineralization using the hydrolysis solution of PG decomposition products. A carbonization rate greater than 90% was obtained when the liquid phase absorption reached saturation. In addition, lower temperatures and higher CO2 partial pressures favoured CMS. To confirm the operating strategy underlying calcium carbonate crystallization, real-time experiments data obtained from process analytical technologies (PATs) and solutions of population balance equations were used to determine parameters of crystallization kinetic models. The match between model simulation experiments and online experimental results throughout the crystallization process confirms the robustness of our findings.