仿生碳化中天冬氨酸对碳酸钙晶型和形貌的影响

Effects of aspartic acid on polymorph and morphology of calcium carbonate in biomimetic carbonation

采用天冬氨酸(Asp)作为晶型诱导剂,采用碳化法合成了球霰石型碳酸钙。研究了二氧化碳通气速率、反应温度、天冬氨酸浓度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)、激光粒度仪分析了产物的晶型特征。结果表明,二氧化碳通气速率对碳酸钙的晶型几乎没有影响,仅影响颗粒的形貌,其中球霰石物质的量分数达到95%,团聚颗粒尺寸随着二氧化碳通气速率的增加而增大;反应温度对碳酸钙晶型的影响较小,对颗粒的形貌、尺寸没有影响,在低温段(20℃)形成的球霰石物质的量分数约为96%,随着温度升高至60℃球霰石物质的量分数降低至87%;天冬氨酸的浓度显著影响碳酸钙的晶型,天冬氨酸浓度越低球霰石含量越低,并且碳酸钙颗粒的形貌由球形逐渐转变为针状,其尺寸也逐渐减小。研究结果对球霰石型碳酸钙的工业化生产提供了较好的借鉴。

Vaterite CaCO_3 crystals with a spherical shape were successfully prepared with aspartic acid（Asp） as the interferon inducer.The effects of CO_2 flow rate,reaction temperature,and Asp concentration on polymorph and morphology of calcium carbonate were investigated,and crystalline products were characterized by X-ray diffraction,field emission scanning electron microscopy,and laser particle analyzer.The experimental resulted indicated that CO_2 flow rate had no effect on the polymorph of CaCO_3,but on the morphology of particles.The mole fraction of vaterite could reach 95%,and the size of agglomerates increased with the increase of CO_2 flow rate.Reaction temperature had a little effect on the polymorph of CaCO_3.The mole fraction of vaterite was 96% at low temperature（20 ℃） and it decreased to 87% when temperature rised to 60 ℃.Asp concentration had remarkable impact on CaCO_3,and the mole fraction of vaterite decreased with increasing Asp concentration and the calcium carbonate changed its shape from sphere to aciculiform. Hence,the study of effects on the polymorph and morphology of CaCO_3 would provide a good reference to the industrial production of vaterite.