牡蛎壳水热—盐析法制备高白度碳酸钙粉体及其表征

Preparation of High Whiteness Calcium Carbonate Powder by Oyster Shell Hydrothermal-salting Method and Its Characterization

以牡蛎壳为原料,采用水热处理工艺和盐析技术制备高白度碳酸钙粉体。利用X射线衍射仪、透射电子显微镜、粉体白度测试仪、红外光谱仪等分析技术,研究水热一盐析工艺对碳酸钙粉体蒔性的影响规律。结果表明:牡蛎壳和碳酸钙粉体的晶型都是方解石型结构,碳酸钙粉体白度随pH值上升,水热温度升高,呈现出先增大后降低的趋势。190t反应3h,粉体白度达到最大值91%。在水热反应过程中添加N^SO,作为中性盐,通过盐析作用,降低粉体中有机杂质,碳酸钙粉体白度提高到91.7%,碳酸钙粉体的晶粒尺寸为500nm.

High whiteness calcium carbonate powder was prepared by using oyster shell as raw material and hydrothermal treatment and salting out technique. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, powder whiteness tester, red infrared spectrometer and other analytical techniques were used to study the influence of hydrothermal-salting process on the characteristics of calcium carbonate powder. The results showed that the crystal forms of oyster shell and calcium carbonate powder were calcite - type structure. The whiteness of calcium carbonate powder increased with the increase of the pH value and the temperature of hydrothermal. 190%^ reaction for 3h, the powder whiteness reached a maximum of 91 %.In the hydrothermal reaction process, Na2S04 was added as a neutral salt, and the organic impurities in the powder were reduced by salting out,and the whiteness of the calcium carbonate powder was further improved to 91.7%.The grain size of the calcium carbonate powder was 500 nm.