Method for purifying byproduct hydrochloric acid in chloroacetic acid production process

A method for purifying byproduct hydrochloric acid in a chloroacetic acid production process comprises the following steps that: 1, sulfur dioxide converted from sulfur in byproduct HCl gas is reactedwith excessive chlorine in the presence of water to convert the sulfur dioxide into sulfuric acid and HCl by using redox reaction; and 2, residual chlorine in the HCl gas is converted into hydrogen chloride through a reducing agent, the HCl gas is purified or hydrochloric acid is purified. The method is simple in process, low in cost and good in purification effect. 一种生产氯乙酸工艺过程中副产盐酸的纯化方法，所述纯化方法是利用氧化还原反应，第一步将副产HCl气体中由硫磺转化来的二氧化硫用过量的氯气在有水存在的情况下反应转化为硫酸和HCl；第二步利用还原剂将HCl气体中残留的氯气转化为氯化氢，HCl气体得到净化或盐酸得到纯化，本方法工艺简单，成本低廉，纯化效果好。