六水铝酸三钙(C_3AH_6)与CO_2反应的研究  

Reaction of tricalcium aluminate hexahydrate(C_3AH_6) with carbon dioxide

作　　者：刘伟[1] 张海宝[1] 周秋生[1] 彭志宏[1] 齐天贵[1] 李小斌[1] 刘桂华[1] 

机构地区：[1]中南大学冶金科学与工程学院,湖南长沙410083

出　　处：《中南大学学报（自然科学版）》2011年第3期595-599,共5页Journal of Central South University:Science and Technology

基　　金：国家重点基础研究发展计划("973"计划)项目(2005CB6237-02);湖南省科技重大专项项目(2009FJ1009)

摘　　要：为了阐述C3AH6与CO2反应的机理,应用X线衍射和pH酸度分析等方法,对C3AH6与CO2反应的影响因素、反应过程及其产物进行研究;结合C3AH6和CO2在水体系中反应时溶液pH的变化规律,提出C3AH6与CO2在水中的反应机理。研究结果表明:在空气和乙醇介质中,C3AH6与CO2的反应十分缓慢;但以水作为反应介质时,C3AH6与CO2的反应显著加快,其产物为CaCO3,Al(OH)3和H2O,且随着反应温度和CO2体积分数的增加以及反应时间的延长,反应率增加;在温度为75℃,CO2体积分数为100%的条件下反应80 min,反应率可达到97.76%;C3AH6与CO2在反应初期主要取决于C3AH6的水化作用,而在反应后期主要取决于H2CO3的电离作用;在水介质中,通入CO2回收C3AH6中的氧化铝是可行的。In order to elucidate the reaction mechanism of tricalcium aluminate hexahydrate（C3AH6） with CO2,the influencing factors such as reaction medium and the concentration of CO2 in the mixture of CO2 and air,reaction process and the products were studied by XRD and pH acidity analyses.The reaction mechanism of C3AH6 and CO2 was proposed.The results show that the reaction rate of C3AH6 with CO2 is extremely slow both in the air and in the ethanol medium.However,in the medium of water,the reaction occurs quickly with the products of aluminum trihydroxide,calcium carbonate and water.And the reaction rate increases with the increase of the reaction temperature,CO2 concentration and reaction time.Under the optimized conditions of 75 ℃,pure CO2 and reaction time of 80 min,the reaction rate can reach 97.76%.The reaction mechanism is that the reaction rate is determined mainly by the solvation of C3AH6 in the initial stage of the reaction and subsequently by the ionization of carbonic acid in the late reaction stage.It is feasible to recover the alumina from C3AH6 by using CO2 as the reagent in water medium.

关 键 词：六水铝酸三钙(C3AH6) 二氧化碳 氧化铝 反应机理 

分 类 号：TF802[冶金工程—有色金属冶金]