起始物料对CA_6-MA轻质骨料性能的影响

Effects of starting materials on performance of CA_6-MA lightweight aggregates

针对以往合成CA6-MA轻质骨料主要采用固体起始物料时Ca O和Mg O分散度有限之不足,以菱镁矿、碳酸钙和氢氧化铝为主要原料,尝试了用可溶性盐Ca Cl2(加入质量分数分别为1%、3%、5%、7.2%)和Mg Cl2·6H2O(加入质量分数分别为1%、3%、5%、7%、9%)分别替代碳酸钙和菱镁矿,研究了其对CA6-MA轻质料的体积密度、强度和显微结构的影响。结果表明:1)Ca Cl2和Mg Cl2·6H2O分别替代碳酸钙和菱镁矿作为Ca O和Mg O源均可制得CA6-MA轻质骨料。2)Mg Cl2·6H2O或Ca Cl2的加入对CA6-MA轻质骨料的物相影响不大,却明显改变了轻质骨料的显微结构;与引入Ca Cl2相比,引入Mg Cl2·6H2O更有利于生成交叉排列的片状CA6及制备低体积密度、高强度、微孔的CA6-MA轻质微孔骨料。3)Mg Cl2·6H2O的最佳加入量为5%(w)。

Aiming at solving the limited dispersion of CaO and MgO in the previously prepared CA6-MA lightweight aggregates,CA6-MA lightweight aggregates were prepared using magnesite,calcium carbon- ate and aluminum hydroxide as starting materials and soluble salts MgCl2 · 6H2O（ 1% ,3% ,5% ,7% ,9%, by mass） and CaCl2 （1% ,3% ,5% ,7.2%, by mass） to replace magnesite and calcium carbonate, respec- tively. The bulk density, strength and microstructure of the lightweight aggregates were investigated. The results show that：（1） using soluble salts CaCl2 and MgCl2 · 6H2O to replace calcium carbonate and mag- nesite,respectively can prepare CA6-MA lightweight aggregates; （2）introducing CaCl2 or MgCl2· 6H2O has a little influence on phase composition, but obviously changes the microstructure of CA6-MA light- weight aggregates ;compared with the introduction of CaCIR,the introduction of MgCl2 · 6H2O is more ad- vantageous to the preparation of CA6-MA lightweight aggregate with flake CA6, arranged across,low bulk density, high strength and micro pores;（3）the optimum addition of soluble salt MgCl2 · 6H2O is 5% .