循环法制备高纯碳酸钙工艺研究

目的制备电子陶瓷工业用高纯碳酸钙。方法以工业碳酸钙为原料,采用改进的氢氧化物沉淀法,经过煅烧、浸出、沉淀、碳化等步骤制备高纯碳酸钙,并用原子吸收分光光度法和电位滴定法对杂质进行了分析,用粒度分析仪对产品粒度分布进行了测定。结果得到一条循环法生产高纯碳酸钙的优化工艺路线,该工艺过程如下:原料经煅烧后与氯化铵反应,加入沉淀剂过滤,除去杂质;将前工序煅烧时产生的CO2气体通入过滤后的滤液中,进行碳化反应;生成物经过滤干燥后即得到高纯碳酸钙;滤液循环使用。结论浸出温度,浸出时间,pH,pH调节试剂,碳化温度,洗涤水温等对产品均有影响。

A technological study for producing high-purity calcium carbonate by a recycling process

Aim To produce high-purity calcium carbonate for electronic industry.Methods By using hydroxide deposition,high-purity calcium carbonate is obtained with the process of calcination,maceration,deposition and carbonization.The product is analyzed by AAS,potential titration and separator-size analyzer.Results An optimal process is obtained to produce high-purity calcium carbonate.The process is that calcined raw materials react with ammonium chloride and filtrate by means of adding precipitator to get rid of the impurity;carbon dioxide gas produced in the former process is added to the filtration to take the carbonization reaction and high-purity calcium carbonate is obtained after filtration and desiccation;the filtration of ammonium chloride can be used circularly.Conclusion The results show that the temperature and time of maceration,pH,adoption of reagent for pH,temperature ofcarbonization and temperature of water all affect preparation.