CO2碳酸化石灰岩酸解产物回收乙酸及副产沉淀碳酸钙

摘要

Acetic acid dissolution of limestone for formation of cavity is a kind of environmental approach to fabricating underground storage and preparing precipitated calcium carbonate. This process is an integrated technology consisting of acetic acid dissolution of limestone and CO2 carbonation of calcium acetate. The kinetics of limestone acidolysis with acetic acid was investigated. Orthogonal experiments were conducted with emphasis on operation conditions (i.e., concentration of calcium acetate, pressure of CO2, reaction temperature, and reaction time) of the carbonation reaction. The highest conversion of calcium acetate (23.13%) was achieved at the calcium acetate concentration of 0.631 mol·L-1, CO2 pressure of 5 MPa, reaction temperature of 80℃ and reaction for 50 min. The product of calcium carbonate was analyzed and could meet the requirements of Chinese national standard.%乙酸酸解石灰石造腔是一种建造地下储库同时环保地开采石灰岩制备沉淀碳酸钙的新方法。通过耦合乙酸酸解石灰石及酸解产物乙酸钙 CO2碳酸化的工艺过程，研究了乙酸酸解石灰岩的表面反应动力学和乙酸钙 CO2碳酸化的工艺技术条件。采用正交实验分析法，研究了CO2碳酸化反应中乙酸钙浓度、反应温度、CO2压力、反应时间对乙酸钙碳酸化反应制沉淀碳酸钙的影响，并通过正交实验确定了最优化操作条件。实验结果表明，乙酸酸解反应速率主要受乙酸浓度控制。CO2碳酸化反应在当乙酸钙溶液浓度为0.631 mol·L-1，CO2压力为5.0 MPa，温度为80℃，反应时间为50 min时CO2碳酸化效率达到最高（23.13%），生成的沉淀碳酸钙产品各项指标均符合中国国标优级要求。