磷石膏中磷的分析及对性能影响研究

Study on analysis of P_2O_5 in Phosphogypsum and their Influence on Properties

可溶磷是磷石膏中主要有害杂质。研究了不同形态可溶磷、共晶磷对磷石膏性能的影响 ,测定了磷石膏中磷、可溶磷及共晶磷含量 ,用扫描电镜及光电子能谱研究了可溶磷的存在形式及其分布。结果表明 :可溶磷主要分布在磷石膏晶体表面 ,其含量随磷石膏粒度增加而增加 ;共晶磷则随磷石膏粒度增加而减少。可溶磷、共晶磷降低硬化体强度。当磷石膏胶结材水化时 ,不同形态磷转化为难溶盐 ,覆盖在二水石膏晶体表面 ,阻碍其溶解与水化 ,使其缓凝。石灰中和磷石膏可降低磷影响 ,是提高磷石膏性能的一种合理方法。

Water soluble P 2O 5 is a main harmful impurity in phosphogypsum.Effects of the different forms water soluble P 2O 5 and P 2O 5 in crystal lattices of gypsum on the phosphogypsum properties were studied.By means of DSC and SEM,the forms and distributions of water soluble P 2O 5 were studied.Experiment results show that water soluble P 2O 5 is distributed on the surface of phosphogypsum.Its content increases with increase of size phosphogypsum,but P 2O 5 in crystal lattices to the contrary.They reduce the strength of hardened body.During phosphogypsum binder hydration,P 2O 5 becomes insoluble precipitate that covers the surface of phosphogypsum and hinders gypsum to dissolve,hydrate and set.The pretreatment technology of neutralizing with quick lime can eliminate the harmful influence of water soluble P 2O 5,it is a effective method to improve the properties of phosphogypsum.