盐湖副产硫酸钙转化法制备高纯氧化钙  

Preparation of high-purity calcium oxide from salt lake by-product calcium sulfate by conversion method

作　　者：冯雅丽[1] 马玉文[1] 李浩然[2] 

机构地区：[1]北京科技大学土木与环境工程学院,北京100083 [2]中国科学院过程工程研究所生化工程国家重点实验室,北京100190

出　　处：《中南大学学报（自然科学版）》2012年第8期3308-3313,共6页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(20876160);国家高技术研究发展计划("863"计划)项目(2007AA05Z158)

摘　　要：利用盐湖副产硫酸钙和碳酸氢铵溶液进行转化反应得到氧化钙的前驱体碳酸钙;然后,将其直接热解制备高纯氧化钙,分别考察物料配比、反应时间、反应温度等因素对硫酸钙转化率的影响,采用XRD和化学分析方法对产物进行分析,并对转化反应过程进行动力学分析。研究结果表明,在物料配比为1.3:1.0,反应时间为2.5 h,反应温度为50℃时,硫酸钙的转化率可达到99.6%,将固相产物在1 000℃热解1 h后所制备的氧化钙纯度为99.7%。转化反应过程符合收缩核模型,其的数学表达式为kt=1-(1-X)1/3,反应的表观活化能为43.4 kJ/mol,该模型表明转化反应过程受界面化学反应控制。The precursor of CaO was prepared by the conversion reaction between salt lake by-product CaSO4-2H2O and NH4HCO3 solution. And then high purity CaO was prepared by pyrolyzing. The effects of mole ratio of NHaHCO3 to CaSOa-2H2O, reaction time and temperature on the conversion rate were investigated respectively. The products were analyzed by XRD and chemical analytical method. The kinetic analysis of the conversion reaction process was made. The results show that the conversion rate of CaSO4·2H2O can reach 99.6% under the conditions of mole ratio 1.3：1.0, reaction time 2.5 h and temperature 50 ℃. The CaO with purity of 99.7% can be prepared by the pyrolysis of solid product at 1 000 ℃ for 1 h. The kinetic analysis demonstrates that the conversion process is in accordance with shrinking core model, which is expressed as a mathematical formula of kt=l-（1-X）1j3 and the apparent activation energy is 43.4 kJ/mol. The model indicates that the conversion process is controlled by the interface chemical reaction process.

关 键 词：盐湖硫酸钙 碳酸钙 高纯氧化钙 转化法 收缩核模型 

分 类 号：TQ177.2[化学工程—硅酸盐工业]