Study on the Formation of Calcium Carbonate by Carbon Sequestration of Phosphogypsum

Abstract Currently, the utilization and treatment of solid waste resources and the recycling of greenhouse gas CO 2 need to be urgently addressed. Calcium carbonate powder was prepared by extracting Ca 2+ from phosphogypsum, a by-product of wet-process phosphoric acid, with ammonium acetate solution and fixing CO 2 with leaching solution. The effects of ammonium acetate concentration, liquid-solid mass ratio, reaction temperature, and reaction time on the leaching rate of Ca 2+ , and the effects of ammonia addition, CO 2 concentration, and carbonization time on the conversion rate of Ca 2+ were systematically studied. SEM, XRD, and particle size analysis were used to analyze the morphological characteristics and formation mechanism of carbonized products under different ammonia additions and carbonization times. The results show that under the optimal conditions, the leaching rate of Ca 2+ can reach 97.9%, the conversion rate of calcium carbonate can reach 91.78%, and the D50 of calcium carbonate powder is 14.7 μm.