SO_(4)^(2-)对烟气洗涤废水镧盐除氟的影响  

Influence of sulfate ion on fluoride removal from flue gas scrubbing wastewater using lanthanum salts

作　　者：钟晓聪 陈晨 严康[1,2] 张魁芳 王瑞祥 徐志峰[2] Xiao-cong ZHONG;Chen CHEN;Kang YAN;Kui-fang ZHANG;Rui-xiang WANG;Zhi-feng XU(Faculty of Materials Metallurgy and Chemistry,Jiangxi University of Science and Technology,Ganzhou 341000,China;Key Laboratory of Ionic Rare Earth Resources and Environment,Ministry of Natural Resources,Ganzhou 341000,China;Ganzhou Engineering Technology Research Center of Green Metallurgy and Process Intensification,Ganzhou 341000,China;Institute of Resources Utilization and Rare Earth Development,Guangdong Academy of Sciences,Guangzhou 510650,China)

机构地区：[1]江西理工大学材料冶金化学学部,赣州341000 [2]自然资源部离子型稀土资源与环境重点实验室,赣州341000 [3]赣州市绿色冶金与过程强化工程技术研究中心,赣州341000 [4]广东省科学院稀土资源利用与开发研究所,广州510650

出　　处：《Transactions of Nonferrous Metals Society of China》2023年第11期3560-3569,共10页中国有色金属学报（英文版）

基　　金：supported by the National Key Research and Development Program of China(No.2019YFC1908405);Natural Science Foundation of Jiangxi Province,China(No.20202BAB214015);Training Plan for Academic and Technical Leaders of Major Disciplines in Jiangxi Province,China(No.20212BCJ23006);Program of Qingjiang Excellent Young Talents,Jiangxi University of Science and Technology,China,Guangdong Basic and Applied Basic Research Foundation,China(No.2021A1515012268);China Postdoctoral Science Foundation(No.2021M702504);Distinguished Professor Program of Jinggang Scholars in Institutions of Higher Learning,Jiangxi Province,China.

摘　　要：以La(NO_(3))3·6H_(2)O为沉淀剂从模拟烟气洗涤废水脱除氟离子。采用氟离子选择性电极、SEM、EDS和XRD研究SO_(4)^(2-)浓度和添加顺序对残留氟浓度和沉淀性质(质量、形貌、物相和成分)的影响规律。结果表明,在含SO_(4)^(2-)模拟烟气洗涤废水中生成的沉淀主要为不规则块状的LaF_(3)晶体。然而,沉淀中同时存在无定形态颗粒,推断其为La[SO_(4)]F。与LaF_(3)相比,La[SO_(4)]F中F/La化学计量系数更小,La原子利用效率更低。因此,随着模拟烟气洗涤废水SO_(4)^(2-)浓度增加,残留氟浓度上升。采用镧盐-SO_(4)^(2-)的添加顺序可以抑制无定形La[SO_(4)]F的生成,有利于降低残留氟浓度。当La/F摩尔比为1:3.0,依次添加La(NO_(3))3∙6H_(2)O和SO_(4)^(2-)(0.02mol/L),可将模拟烟气洗涤废水氟离子浓度降至6.9mg/L,低于排放标准。进一步提高La/F摩尔比,可以获得更低的残留氟浓度(<2mg/L),然而可能导致La^(3+)残留的风险。Batch experiments were conducted to remove fluoride from simulated flue-gas scrubbing wastewater using 2-La(NO_(3))3·6H_(2)O.The effects of SO_(4) concentration and addition sequence on residual fluoride concentration and precipitates properties(mass,morphology,phase structure and composition)were investigated using fluorine 2-ion-selective electrode,SEM,EDS and XRD.The results show that precipitates obtained in the presence of SO_(4) mainly consisted of LaF_(3) in irregular bulk shape with high crystallinity.However,amorphous particles were observed in the precipitates,which were speculated to be La[SO_(4)]F.Due to the smaller stoichiometric coefficient of F/La in La[SO_(4)]F 2-compared to that in LaF3,the residual fluoride concentration increased as the SO_(4) concentration ascended.Subsequent 2-addition of SO_(4) after lanthanum salt could inhibit the formation of amorphous particles,and further reduce the residual 2-fluoride concentration.At a La/F molar ratio of 1:3.0,the subsequent addition of SO_(4)(0.02 mol/L)after La(NO_(3))3∙6H_(2)O could obtain a residual fluoride concentration of 6.9 mg/L,lower than the required fluoride emission level.Further increasing the La/F molar ratio could reduce residual fluoride concentration to below 2 mg/L,while the risk of retaining La^(3+)would emerge.

关 键 词：除氟 镧盐 无定形颗粒 原子利用效率 添加顺序 

分 类 号：X701[环境科学与工程—环境工程]