缓凝剂在磷石膏水化进程中的影响  

The influence of retarders in the hydration process of phosphogypsum

作　　者：陈明凤[1] 杜勇[1] 彭家惠[1] 张建新[1] 瞿金东[1] 

机构地区：[1]重庆大学材料科学与工程学院,重庆400045

出　　处：《重庆大学学报（自然科学版）》2010年第11期77-83,共7页Journal of Chongqing University

基　　金：国家自然科学基金资助项目(50572126)

摘　　要：通过缓凝剂对磷石膏凝结时间、强度、水化率、水化温升与液相离子浓度测定,结合扫描电镜观察,研究了缓凝剂对磷石膏水化进程的影响。结果表明:SG-10、柠檬酸缓凝剂与磷石膏适应性较好;pH值对缓凝剂缓凝效果有很大影响,SG-10和柠檬酸在磷石膏浆体中最佳pH值分别为5.1和6.0时:柠檬酸掺量不宜超过0.1%,SG-10掺量不宜超过0.2%;SG-10、柠檬酸在水化初期使水化放热明显变缓,早期水化率显著降低,最终水化率有所降低,一定程度上改变了磷石膏水化动力学过程;缓凝剂掺入后,石膏初始液相离子浓度和过饱和度低于空白样,水化反应过程中液相离子浓度和过饱和度降低速率大幅降低;SG-10的掺加使二水石膏晶体尺度增大,但对二水石膏晶体形貌影响较小,掺柠檬酸时,硬化体晶体形貌改变较大。The influence of retarders on the hydration process of phosphogypsum is investigated by determining setting time,intensity of hardened anhydrite,hydration rate,hydration temperature increase and the degree of solution supersaturation in combination with observing by scanning electron microscope.The results indicate that SG-10 and citric acid retarder can adapt to phosphogypsum well;pH value has a great influence on the retarding effect,5.1 and 6.0 are the best pH values for the effect of SG-10 and citric acid in plaster of phosphogypsum respectively.However,citric acid dosage should not exceed 0.1% or the amount of doped-SG-10 should not more than 0.2%.Both SG-10 and citric acid lead to a delay in the hydration heat evolution and significantly decrease the hydration ratio in the early stage and the ratio of recede limited in the final hydration.It can also partly change the hydration kinetics process of phosphogypsum at the same time.Initial liquid concentration and over-saturation of phosphogypsum are less than the blank sample after adding retarder,while liquid phase ion concentration and decreased ratio of over-saturation simultaneously are sharply depressed in the hydration reaction process.SG-10 causes the large crystal sizes,but it has a minor effect on the crystal morphology of dehydrate.Adding citric acid result in a large influence on the dehydrated crystal morphology of phosphogypsum.

关 键 词：磷石膏 缓凝剂 掺量 PH值 水化进程 

分 类 号：TQ177.375[化学工程—硅酸盐工业]