提升产品附加值对改善二氧化碳矿化过程的经济性具有重要意义。在二水硫酸钙与碳酸铵溶液进行间接矿化反应过程中,采用十六烷基三甲基溴化铵（CTAB）为晶型调节剂,可以获得球霰石晶型的碳酸钙。系统研究了反应时间、反应温度、CTAB加入量对碳酸钙晶型和形貌的影响,通过X射线衍射（XRD）、扫描电镜（SEM）和红外光谱（FT-IR）对碳酸钙的晶型、形貌进行了表征。结果表明：反应过程为先形成亚稳定相的球霰石,再向热力学最稳定的方解石相转化;添加CTAB能够明显地增强球霰石的稳定性;较低温度有利于球霰石的形成;在反应温度为30 ℃、二水硫酸钙和碳酸铵加入量均为0.1 mol/L、CTAB加入量为0.54 mmol/L条件下,碳酸钙中球霰石占比高达80%以上;CTAB在球霰石表面上的吸附降低了其表面能,从而抑制了球霰石向方解石的转化。

Increasing the added value of products is of great significance for improving the economy of CO₂ mineralization process.In the indirect mineralization process of calcium sulfate dihydrate and ammonium carbonate solution,cetyltrimethy-lammonium bromide（CTAB） was used as the crystal regulator to obtain calcium carbonate composed of vaterite crystal form. The effects of reaction time,reaction temperature and the dosage of CTAB on the crystal and morphology of calcium carbonate were studied systematically.The crystal and morphology were characterized by XRD,SEM and FT-IR.The results showed that the reaction process begined with the formation of metastable phase vaterite which continued to convert to calcite with the highest thermodynamic stability.The addition of CTAB can significantly enhance the stability of vaterite; lower temperature was beneficial to form vaterite;when the reaction temperature was 30 ℃,CaSO₄·2H₂O solid powder and（NH₄）₂CO₃ solution were both 0.01 mol/L and CTAB was 0.54 mmol/L,the proportion of vaterite in the product was higher than 80%.The adsorption of CTAB on the product surface reduced the surface energy and inhibited the conversion of vaterite to calcite.