中文摘要：

通过x射线衍射（XRD），红外光谱（Fr-IR）等手段研究了石灰法除磷的主要产物，探讨了除磷过程中关键控制条件——pH值的选择机制．结果表明：常温下石灰法除磷初期产物有DCPD（CaH-PO4.2H20），但存在时间极短就转化为TCP（Ca3（P04）2·xH20），实际产物表现为TCP→HAP（Cal。（OH）：（PO。）。）的转化过程．10min后转化率〉50％，完全转化的时间〉30min，实际生产的工艺条件下除磷产物是以HAP为主的HAP与TCP混合物．pH条件对除磷效果有决定性影响，OH-主要有以下两方面作用：1．控制酸碱环境提供沉淀条件；2．作为主要除磷过程的反应物．除磷过程所需要的[Ca2’]间接决定了反应过程中溶液的pH参数，这是石灰法除磷过程中pH值的选择机制．石灰法除磷需要控制的pH参数只与废水初始pH值和磷酸盐浓度有关，其计算式为：pH=14＋lg（k2a＋2k2a），式中k2、k3分别为H2P04-与HPO^2-4在初始酸碱环境下的分布系数，a为磷初始浓度（mol／L）．

英文摘要：

The products of phosphate removal by Ca （ OH ） 2 were investigated with the tests of XRD and FT - IR. The choosing Mechanism of reaction pH value which is the key factor for phosphate removal was studied. XRD and FF -IR tests indicate that CaHPO4 . 2H20 （DCPD） was preformed at initial stage of, hut only existed for a short time, then transformed to Caa{PO4）2 . xH20 （TCP）. The main product of phosphate removal could be descried as a process of Ca3 （ PO4 ）2 ~ xH20 （TCP） →Calo （ OH ） 2 （ P04 ） 6 （ HAP ）. In the process of phosphate removal OH- plays 2 roles： 1. maintaining the reaction pH to provide precipitation con dition ; 2. as a material for phosphate removal reaction. The optimal reaction pH value indirect ly lay on phosphate concentration which decided the [ Ca2 ^＋ ]. The optimal reaction pH value is only related to initial pH and phosphate concentration. It can be calculated as ： pH = 14 ＋ lg（ k2a ＋ 2k3a）. k2, k3 were the distribution coefficient of H2PO4 - and HP042-, a was the concentration of ohosohate { mol/LI.