电石渣制备碳酸钙微粉的晶型转变

Crystal transformation of calcium carbonate micro-particles prepared from carbide slags

为了提高电石渣的附加值,在未使用晶型诱导剂的情况下,研究盐酸的用量、提取温度和二氧化碳的流量对电石渣合成碳酸钙形貌的影响。用XRD、FT-IR表征了合成的产物,用扫描电子显微镜（SEM）观察研究了产物粒子的形状,结果表明,盐酸的用量和提取温度均会对碳酸钙的晶型和形状有影响。随着盐酸用量的增大,碳酸钙由不规则的方解石型转变为部分规则的球状结构,当浸取剂完全是盐酸的时候,碳酸钙的晶型从方解石型完全转变为球霰石型结构,颗粒粒径为4~5μm。另外,当提取温度从18℃升高到30℃以上后,碳酸钙由方解石和球霰石两种晶体结构并存的状态转变为单一的球霰石型结构。

To improve the added values of carbide slags,the effects of HCl dosage,extracting temperature,and CO_2 flow rate on the morphology of calcium carbonate micro-particles prepared from carbide slags without crystal controlling agents were investigated.The as-prepared products were characterized by X-ray diffraction and FT-IR.The shapes of particles were observed by scanning electron microscopy.Results showed that HCl dosage and extracting temperature were important parameters for the control of morphology and shape of CaCO_3.Calcium carbonate was changed from irregular calcite to partially regular vaterite with the increase of HCl content.The vaterite micro-particles can be prepared and the particle size was at 4 ~5 μm when the leaching agent was completely HCl.In addition, single vaterite micro-particles can be prepared from co-existed calcite and vaterite particles,when the extracting temperature was above 30 ℃ from 18 ℃.