中文摘要：

针对脱硫建筑石膏凝结硬化快的特点，研究了硼砂对脱硫建筑石膏水化进程与二水石膏晶体形貌的影响，以及不同pH值时硼砂的缓凝效果，结合光电子能谱技术对其缓凝机理进行了分析。结果表明，硼砂可以抑制脱硫建筑石膏早期水化，使其水化放热减缓，凝结时间延长，但石膏硬化体强度有所降低；硼砂在碱性的水化条件下对脱硫石膏缓凝效果最佳，在pH值=10时凝结时间出现峰值：硼砂的掺入会改变二水石膏的晶体形貌，使二水石膏形貌由针状变成短柱状，晶体尺寸明显粗化，晶体之间搭接不良，引起强度损失；硼砂与脱硫石膏表面钙元素发生络合作用，在其表面形成化学吸附层，抑制晶核长大，延缓石膏水化进程。

英文摘要：

As FGD building gypsum has a character of fast solidity,the effect of borax on the hydration process and crystal morphology of dehydrate of FGD building gypsum and relationship between pH value and retarding effect were analyzed. Furthermore,by using the X-ray photoelectron spectroscopy technique,its retarding mechanism was also studied. The results indicate that the addition of borax retards the early hydration of FGD building gypsum,which leads to a delay in the hydration heat evolution. It can also prolong the setting time but has a little influence on Strength development. Borax has a better retarding effect in alkaline hydration conditions and the setting time reaches the peak point when pH=10. The addition of borax will lead to the transformation of dihydrate crystal from needlelike to short prismatic. It could cause the large crystal sizes and few links between crystals,in that the strength will be lower. Borax interacts with the Ca element on the crystal nuclei surface of dehydrates and forms a chemical adsorption layer, inhibiting its growth,and consequently slowing down the hydration process.