中文摘要：

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．

英文摘要：

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.