碳化法制备多孔碳酸钙的工艺研究

Study on preparation process of porous calcium carbonate by carbonization

以石灰石为原料,采用碳化法制备多孔碳酸钙。以多孔碳酸钙的比表面积作为评价指标,探究消化时间、消化温度、液固比、模板剂浓度、碳化温度、CO_(2)流量等对多孔碳酸钙比表面积的影响,得出最佳的制备工艺条件。结果表明,以十二烷基硫酸钠(SDS)为模板剂,在最佳制备条件(消化时间为1 h、消化温度为60℃、液固比(体积质量比,g/mL)为14∶1、SDS浓度为0.1 mol/L、碳化温度为30℃、碳化CO_(2)流量为400 mL/min)下制备的多孔碳酸钙比表面积可达60.17 m^(2)/g。利用扫描电镜(SEM)、X射线衍射(XRD)等表征手段对所得多孔碳酸钙的颗粒形貌、晶型进行了分析,结果显示在最佳制备工艺条件下制备的多孔碳酸钙颗粒表面粗糙,孔道结构清晰可见,晶型为稳定的方解石型。

Limestone was used as raw material to prepare porous calcium carbonate by carbonization.In order to obtain the best preparation process conditions,the effects of digestion time,digestion temperature,liquid‐solid ratio,template concen‐tration,carbonation temperature and carbonation CO_(2) flow on the specific surface area of porous calcium carbonate were in‐vestigated by taking the specific surface area of porous calcium carbonate as the evaluation index.The results showed that sodium dodecyl sulfate(SDS)was used as template,the optimum preparation conditions were as follows:digestion time was 1 h,digestion temperature was 60℃,liquid‐solid ratio was 14∶1,SDS concentration was 0.1 mol/L,carbonization tempera‐ture was 30℃,and carbon dioxide flow rate was 400 mL/min.Under these conditions,the specific surface product of porous calcium carbonate could reach 60.17 m^(2)/g.The particle morphology and crystal form of porous calcium carbonate were ana‐lyzed by scanning electron microscope(SEM)and X-ray diffraction(XRD).The results showed that the porous calcium car‐bonate particles prepared under the optimal preparation conditions had rough surface,clearly visible pore structure and stable calcite crystal form.