含氟废水中氟化钙颗粒结晶行为及其可浮性研究

Study on the Crystallization Behavior and Floatability of Calcium Fluoride Particles in Fluorine-containing Wastewater

为解决氟资源加工利用过程中的环境污染问题,并提高含氟废水中氟资源的综合利用率,系统研究了含氟酸性废水中形成的氟化钙结晶颗粒的沉降行为和粒度特征,探索了氟化钙结晶颗粒的浮选特性,并结合Visual MINTEQ软件模拟氟化钙化学沉淀形成过程,利用XRD表征结晶颗粒的物相组成,采用Zeta电位测试分析Na OL与氟化钙颗粒的作用机理。研究结果表明:用氯化钙处理含氟酸性废水时,在强酸条件下,无法形成氟化钙结晶颗粒;在p H>5时,能获得稳定的氟化钙结晶沉淀产物,且废水中F^(-)浓度越高,结晶颗粒数量越多,粒度越大,所获得氟化钙结晶纯度高,几乎不含其他杂质;油酸钠在p H为5~9时,能够吸附在氟化钙结晶颗粒表面,使其具备良好的可浮性,且油酸钠用量与废水中F^(-)浓度呈等比例关系,浮选回收效果良好。该研究结果可为处理含氟废水和回收氟化钙资源提供理论参考。

In order to solve the problem of environmental pollution in the process of processing and utilization of fluorine resources,improve the comprehensive utilization rate of fluorine resources in fluorine-containing wastewater,the sedimentation behavior and particle size characteristics of calcium fluoride crystallization particles in fluorine-containing acidic wastewater were systematically studied,and the flotation characteristics of calcium fluoride crystallization particles were explored.Com-bined with the chemical precipitation formation process of calcium fluoride simulated by Visual MINTEQ software,the phase composition of crystallization particles was characterized by XRD,and the action mechanism between NaOL and calcium fluor-ide particles was analyzed by Zeta potential test.The results showed that when calcium chloride was used to treat fluorine-con-taining acidic wastewater,calcium fluoride crystallization particles could not be formed under strong acid conditions.When pH>5,stable calcium fluoride crystallization precipitation products could be obtained.And the higher the concentration of F^(-)in the wastewater,the more the number of crystallization particles,the larger the particle size.The obtained calcium fluoride crystalli-zation had high purity and almost no other impurities.When the pH was 5~9,sodium oleate could be adsorbed on the surface of calcium fluoride crystallization particles,so that it had good floatability,and the dosage of sodium oleate was proportional to the concentration of F^(-)in the wastewater,and the flotation recovery effect was good.The results of this study can provide a the-oretical reference for the treatment of fluorine-containing wastewater and the recovery of calcium fluoride resources.