In recent years, the technology of using solid waste gypsum to mineralize CO2 and co-produce CaCO3 and ammonium sulfate hasreceived widespread attention. However, due to the complex composition of solid waste gypsum, difficult separation and purificationprocesses, and the difficulty in balancing cost and mineralization products quality, the gypsum mineralization technology is unable toachieve large-scale industrial utilization. Therefore, calcium sulfate and phosphogypsum were used as raw materials and proposed an indirect mineralization process, which firstly using ammonium sulfate solution, a liquid phase product of gypsum mineralization, to enhancethe dissolution and leaching of calcium sulfate, followed by liquid-solid separation, and then mineralized with the calcium sulfate solution.The effects of ammonium sulfate concentration and dissolution leaching time on the dissolution strengthening process were experimentallyinvestigated, and the effects of ammonium concentration, temperature and mineralization reaction time on the mineralization processand mineralization products were discussed as well. The optimized dissolution and mineralization process conditions were determined, basing on which the indirect mineralization process of phosphogypsum was further studied. The experimental results show that, compared withdirect mineralization, indirect mineralization can increase the purity of CaCO3 products from 82.2% to 98.6%, and can decrease the particle size D50 from 22.00 μm to 10.98 μm. The indirect mineralization process can effectively strengthen the dissolution and leaching processof gypsum, avoid the introduction of external media, and prepare high-purity light CaCO3. The present research can provide basic supportfor the economic application of CO2 technology for solid waste gypsum mineralization.

刘妍汝(1998—),女,四川眉山人,硕士研究生。E-mail:1256501581@qq.com

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LIU Yanru,ZHONG Shan,TANG Siyang,et al.Investigation on high-purity CaCO3 by ammonium sulfate enhanced gypsumdissolution mineralization[J].Clean Coal Technology,2024,30(4):137-145.