通过静态实验,分别研究了不同的时间、pH值、铀初始质量浓度、磷灰石用量等条件下磷灰石去除溶液中铀的行为.结合红外光谱、扫描电镜、X衍射和磷析出量等分析结果,初步探讨了天然磷灰石去除铀的机理.结果表明,一定质量的磷灰石对溶液中铀的去除量随铀初始浓度的增大而增大,随着温度的升高先上升后下降.在pH值为3~4,天然磷灰石用量为1.0 g时去除效果最好,铀的去除率高达80%以上,反应在120 min基本达到平衡,反应符合二级动力学方程.XRD分析可知磷灰石主要成份是Ca5H2(PO4)3F、Ca8H2(PO4)6·H2O,扫描电镜分析与含铀溶液反应前后磷灰石矿物形貌变化不大,磷灰石对溶液中铀的去除主要以吸附和离子交换作用为主.
Through the static experiments , the effects of time , pH value , initial concentration of uranium , dosage of apatite on removal of uranium by natural apatite were studied analytically in this paper .In accordance with analysis of infrared spectroscopy , scanning electron microscopy and X ray diffraction , the mechanism of removal of uranium by apatite was discussed .The results show that the removal of apatite , detergent quality of uranium increases with the initial concentration of uranium .When the pH was 3-4 and the apatite content was 1.0 g, the removal ratio was the highest , which could reach as high as 80%.The reaction reached balance in the 120 min with two order kinetics equation .XRD showed apatite was mainly composed of Ca 5 H2 (PO4)3 F, Ca8 H2 (PO4)6 · H2 O.Scanning electron microscope analysis showed that the appearance of apatite did not change in the process of uranium removal .The uptake mechanism of uranium by apatite is mainly adsorption and ion exchange