由于Cl^-对植物的生长具有很高的“氯毒害”,而热镀锌FeCl₂污泥中Cl^-的含量极高,因此不能直接作为一般废物最终处置。采用减压反应蒸馏去除FeCl₂污泥中的Cl^-,由于FeCl₂水解生成的HCl被减压蒸馏带出、Fe（OH）₂在空气曝气作用下氧化成Fe（OH）₃,经过滤干燥后形成水合氧化铁（Fe₂O₃·nH₂O）。实验中首先在自制的减压反应蒸馏装置中进行3因素4水平正交实验研究,随后做单因素优化实验研究。减压反应蒸馏去除FeCl₂溶液中Cl^-的优选工艺条件：FeCl₂浓度为1.50 mol/L、加热温度为75 ℃、反应蒸馏时间为120 min,系统真空度控制在0.06 MPa,Cl^-的去除率达85.5%。将优选的工艺条件应用于热镀锌FeCl₂污泥中Cl^-的去除,其去除率可达84.0%。

Cl^- has been high chlorine toxicity to growth of the plants,and the content of Cl^- in hot-dip galvanized FeCl₂ sludge is very high,so it can not be directly disposed as general waste.In this experiment,Cl^- in FeCl₂ solution was removed by vacuum reactive distillation.At the same time,HCl gas was formed by hydrolysis of FeCl₂ and taken out by vacuum distillation,the Fe（OH）₂ was oxidized to Fe（OH）₃ by air during aeration.And then ferric oxide hydrate（Fe₂O₃·nH₂O） was obtained by filtering and drying.The removal of Cl^- from FeCl₂ solution was designed as 3 factors and 4 levels to carry out orthogonal tests,and the single factor tests were studied.The optimum technological conditions for removal of Cl^- from FeCl₂ solution by vacuum reactive distillation were as follows：FeCl₂ concentration was 1.50 mol/L,heating temperature was 75 ℃,reactive distillation time was 120 min and vacuum degree was 0.06 MPa.Under the conditions,the removal efficiency of Cl^- was up to 85.5%.When the optimum technological conditions were applied to removal of Cl^- from hot-dip galvanized FeCl₂ sludge,the removal efficiency of Cl^- reached 84.0%.