磷酸盐对α半水脱硫石膏凝结硬化的作用机理  

Mechanisms of phosphate on the hydration and hardening of α-hemihydrate desulfurization gypsum

作　　者：彭家惠[1] 刘先锋[1,2] 张建新[1] 瞿金东 赵敏[1] 

机构地区：[1]重庆大学材料科学与工程学院,重庆400045 [2]重庆科技学院建筑工程学院,重庆401331 [3]重庆建大建筑材料有限公司,重庆400030

出　　处：《深圳大学学报（理工版）》2014年第4期388-394,共7页Journal of Shenzhen University(Science and Engineering)

基　　金：国家自然科学基金资助项目(50872160);重庆市自然科学基金资助项目(cstc2011jjA20002)~~

摘　　要：研究磷酸盐对α半水脱硫石膏水化反应进程、液相离子浓度与过饱和度以及水化产物形貌与硬化体强度的影响,结合X光电子能谱分析技术对磷酸盐缓凝机理进行分析.结果表明,磷酸盐抑制α半水脱硫石膏早期水化,使水化放热减缓,早期水化速率降低,凝结时间延长;磷酸盐改变了二水石膏晶体生长习性,晶形由长棒状转化为板状,并使晶体粗化,硬化体强度降低;磷酸盐通过化学作用吸附在二水石膏晶体表面,抑制离子扩散和晶面生长,这是二水石膏缓凝的内因,对晶面的选择性吸附改变了二水石膏晶体生长习性和形貌,是硬化体强度降低的原因所在.The influence of phosphate on the hydration process of α-hemihydrate desulfurization gypsum, ion concentration in liquid phase and supersaturation degree, the crystal morphology of its dihydrate products and the strength of its hardened paste was investigated. Furthermore, its retarding mechanism was analyzed by the X-ray photoelectron spectroscopy technique. The results show that the addition of phosphate inhibits early hydration of gypsum-building, leading to the delay of hydration heat evolution, the decrease of hydration ratio at early stage and the prolonging of the induction period of α-hemihydrate desulfurization gypsum. The addition of phosphate changes the crystalline habit of dihydrate, leading to the transformation of the crystal from a needle-like shape to a short prismatic or plankshaped coarse microstructure with a low strength of hardened paste. Phosphate inhibits ion diffusion and crystal growth by being chemisorbed on a gypsum crystal surface, which is the internal cause of retardation. The selective adsorption of Phosphate on different crystal faces alters the habits crystal growth and the morphology of gypsum, leading to the reduction of the strength of the hardened paste.

关 键 词：建筑材料 α半水脱硫石膏 磷酸盐 水化进程 缓凝机理 硬化 

分 类 号：TU526[建筑科学—建筑技术科学] X773[环境科学与工程—环境工程]