冶炼厂污酸除氟的热力学研究  

Thermodynamics of fluoride removal from waste acid in metallurgy plant

作　　者：李家元[1,2] 周兆安 杨天足[1] 陈霖[1] 

机构地区：[1]中南大学冶金与环境学院,湖南长沙410083 [2]湖南科技学院化学工程与生命科学学院,湖南永州425199 [3]深圳市危险废物处理站有限公司,广东深圳518049

出　　处：《中南大学学报（自然科学版）》2013年第9期3580-3586,共7页Journal of Central South University:Science and Technology

基　　金：国务院水处理专项资助项目(2010ZX07212-008);湖南省科技厅社会发展支撑计划项目(2012SK3112)

摘　　要：利用冶炼厂含氧化铅物料去除污酸中的氟。对H+-F-H2O系和Pb2+-F-- H2O系进行热力学计算,绘制25℃时Pb2+-F--H2O系的E-log[F]图和氟、铅的分布分数图及溶解度曲线图,得到总铅和总氟随游离铅浓度[Pb2+]及pH的变化关系。研究结果表明:在室温下,pH为4~6时溶液中氟和铅主要以游离态的F和Pb2+形式存在;当pH大于7时,溶液中氢氧根离子会显著影响游离铅离子浓度,降低除氟效果;当pH低于4时,溶液中氟主要以HF分子形式存在;确定氟化铅沉淀法除污酸溶液中氟的合适条件为溶液pH=6,铅离子浓度为0.01 mol/L,在此条件下,溶液中的总质量浓度降低至约40 mg/L。该方法可为冶炼厂污酸净化除氟提供新的思路。Fluoride in waste acid was removed by precipitation process with waste residue and dust containing lead oxide.The thermodynamics of H+ -F--H2 O and Pb2-F--H2 O systems were analyzed.The distribution diagram of lead and fluoride species,E log[F-] diagram and solubility curve of lead fluoride diagram at 25 ℃ were drawn.The relationship among the total lead concentration([Pb]T)/fluoride concentration([F]T) and free lead concentration([Pb2+]) and pH were obtained.The results show that lead and fluoride mainly exist as free ions in the solution with pH between 4-6.When pH exceeds 7,free lead ion concentration in the solution is reduced significantly,resulting in the reduction of fluoride removal efficiency.Fluoride exists mostly in the form of HF when solution pH is lower than 4.The optimum conditions for fluoride removal are as follows: temperature is 25 ℃,pH is 6,and total lead concentration is 0.01 mol/L.Under the condition,the total fluoride mass concentration can be decreased to about 40 mg/L.This method can provide a new way in waste acid treating process for metallurgical works.

关 键 词：Pb2+-F--H2O系 污酸 氟化铅 热力学 

分 类 号：TF09[冶金工程—冶金物理化学]