摘要
杂质离子是影响含氟废水结晶沉淀的关键因素之一,为探究杂质离子(Al^(3+)和Si^(4+))对含氟废水钙盐结晶沉淀过程的影响,提高含氟废水的处理效果,利用NaF和CaCl_(2)反应模拟含氟废水沉淀过程,结合Visual MINTEQ软件模拟、XRD表征和SEM-EDS测试,系统研究Al^(3+)和Si^(4+)对沉淀结晶浊度、残余氟离子浓度及沉淀产物特征的影响。研究结果表明,低浓度的Al^(3+)和Si^(4+)对氟化钙结晶沉淀和除氟效果影响较小。当Al^(3+)质量浓度为200.00 mg/L时,碱性条件下反应产生氢氧化铝和冰晶石等杂质沉淀,导致反应浊度升高,残余氟离子浓度随pH升高而降低;当Si^(4+)质量浓度为200.00 mg/L时,结晶沉淀产物中含硅杂质主要为石英和硅酸钙,最佳除氟条件为n(Ca)/n(F)=2.5、pH=9,此时,溶液中残余氟离子质量浓度为5.62 mg/L。SEM-EDS测试表明,沉淀产物呈块状团聚体,氟化钙与杂质产物嵌布关系复杂,分离难度较大。研究结果为实际生产工艺中复杂多离子含氟废水的处理及结晶产物的回收利用提供参考。
Impurity ions are one of the key factors affecting the crystallization and precipitation of fluorine⁃containing waste⁃water.In order to investigate the influence of impurity ions(Al^(3+)and Si⁴⁺)on the calcium salt crystallization and precipita⁃tion process of fluorine⁃containing wastewater and improve the treatment effect of fluorine⁃containing wastewater,the reac⁃tion of NaF and CaCl_(2)was used to simulate the sedimentation process of fluorine⁃containing wastewater.Combined with Vi⁃sual MINTEQ software simulation,XRD characterization,and SEM-EDS testing,the influence of Al^(3+)and Si^(4+)on the turbid⁃ity of precipitation crystallization,residual fluoride ion concentration,and precipitation product characteristics was system⁃atically studied.The research results indicated that low concentrations of Al3+and Si4+had little effect on the precipitation and defluorination of calcium fluoride crystals.When the concentration of Al3+was 200.00 mg/L,impurities such as alumi⁃num hydroxide and cryolite precipitated under alkaline conditions,leading to an increase in reaction turbidity and a decrease in residual fluoride ion concentration with increasing pH.When the concentration of Si4+was 200.00 mg/L,the silicon impurities in the crystal precipitation product were mainly quartz and calcium silicate,and the optimal defluorination condi⁃tions were n(Ca)/n(F)=2.5,pH=9.At this point,the residual fluoride ion concentration in the solution was 5.62 mg/L.SEMEDS testing showed that the precipitate products were in the form of block aggregates,and the embedding relationship be⁃tween calcium fluoride and impurity products was complex,making separation difficult.The research results provided refer⁃ence for the treatment of complex multi ion fluorine⁃containing wastewater and the recycling of crystallization products in ac⁃tual production processes.
作者
李军霄
黄鸶云
解蕾
张雨茜
钱玉鹏
LI Junxiao;HUANG Siyun;XIE Lei;ZHANG Yuxi;QIAN Yupeng(School of Resources and Environmental Engineering,Wuhan University of Technology,Wuhan 430070,China;Hubei Provincial Key Laboratory of Mineral Resources Processing and Environment,Wuhan 430070,China;Key Laboratory of Green Utilization of Critical Non-metallic Mineral Resources,Ministry of Education,Wuhan 430070,China)
出处
《无机盐工业》
北大核心
2025年第12期99-106,共8页
Inorganic Chemicals Industry
基金
湖北省自然科学基金项目(2022CFB433)。
关键词
含氟废水
氟化钙
杂质离子
结晶沉淀
除氟效果
fluorinated wastewater
calcium fluoride
impurity ions
crystalline precipitation
fluoride removal effect
