二氧化氯发生器残液处理方法研究与比较

采用离子交换膜、离子交换树脂和铁粉还原法对复合法制备二氧化氯过程中产生的高浓度氯酸盐残液进行处理,对3种方法进行综合比较。结果表明:离子交换膜处理后氯酸盐富集质量浓度为13.06 g/L,为进水质量浓度的6.5倍,去除率大于50%,离子交换膜不可重复使用;离子交换树脂处理后富集质量浓度为23.51 g/L,为进水质量浓度的11.8倍,去除率为95%,离子交换树脂可重复使用;铁粉对氯酸根去除率为99%,可连续使用15次。综合比较处理效果、控制条件和处理成本,选择铁粉还原法为最佳方法。

Comprehensive comparison of treating methods for residual liquid of chlorine dioxide generator

The present paper intends to make a comparative study of the three methods to prepare high concentrated chlorate residue solution in the process of compound chlorine dioxide by taking chlorate as an oxygen-containing anion with strong oxidizing properties. For this need,it is recommended to use the ion exchange membrane,ion exchange resin and the iron powder reduction method. The ion exchange membrane reactor can be operated continuously and continually. When the initial mass concentration of sodium chloride in the exchange solution is 270 g /L,the reaction temperature should be taken as (25 ± 1) ℃,at the initial pH value of 7. 0,with the stirring intensity being 200 r /min and the running time being 240 minutes. In such a condition,the enrichment mass concentration of chlorate can be 13. 06 g /L,that is,6. 5 times of the influent concentration and the removal rate of about 50％,though the ion exchange membrane fail to be repeatedly employed. The results of the dynamic experiment of the ion exchange resin indicate that the enrichment mass concentration rate of chlorate can be expected to reach 23. 51 g /L,that is,11. 8 times of the influent concentration at the removal rate of 95％. In so doing,the following conditions should be satisfied: the residence time: 19. 6 min; the reaction temperature: (25 ± 1) ℃; the initial pH value: 7. 0,and the lasting time: 240 minutes. Otherwise,if the ion exchange resins wanted to be reused and the iron powder were to be used continuously for 15 times, the following conditions have to be satisfied: the initial pH value:2. 0; the iron powder: 10 g; the rotation speed: 150 r /min; the reaction temperature: (25 ± 1) ℃. In such conditions,the removal rate of chlorate can be made as high as to 99％. And,so far as we know,the cost of ion exchange membrane: about 2. 07 yuan /L; the ion exchange resin: 0. 17 yuan /L; and the iron powder reduction method: at about 0. 10 yuan /L,respectively. And, so far as we know,the control condition of the iron powder reduction method can be expected the simplest one because it only needs to be added and mixed in with the equipment. Thus,as compared in treating effect,processing cost and the control condition, the iron powder reduction method can be chosen as the best one.