硫酸钾副产氯化钠蒸发器结垢原因及处理

Causes and treatment measures of scaling of evaporator of sodium chloride by-produced in the production of potassium sulfate

芒硝复分解法生产硫酸钾，蒸发母液得到副产品氯化钠。生产中氯化钠蒸发器结垢现象严重，清理次数多，生产效率降低，影响正常生产。本研究拟通过对蒸发器中垢样进行分析，制定除垢方案，解决蒸发器结垢现象，提高生产效率。通过对氯化钠蒸发器中垢样的水溶物、酸溶物、酸不溶物成分及含量的分析，总结出氯化钠蒸发器结垢的根本原因是由于母液中的K^＋，Ca^2＋，Fe^3＋，Cl^-，SO4^2-，Mg^2＋，Na^＋，HCO3^-等离子存在。因此采用了提高反应收率、改进蒸发器装置、添加化学助剂、改善工艺条件等处理方法，基本解决了蒸发器结垢的问题。实践表明，通过该方法可使蒸发器清理次数减少至2～3次／a，使除垢简单易行，除垢效果显著。

Potassium sulfate was produced by mirabilite double decomposition reaction and the by - product sodium chloride was obtained from its evaporated mother liquor,but the productivity was reduced due to the sodium chloride evaporator scaling phenomenon in the production process. Removing the sealing needed much more times and the normal production had been affected. In the study, evaporator scaling was solved and the productivity was improved by analyzing the sampies of scale. The samples of scale from sodium chloride evaporation were analysised on the composition and content of water- solublematters ,acid- solublematters, acid- insolublematters. The fundamental cause of scaling in the process of sodium chloride evaporation was summarized, which was due to the existences of K^＋,Ca^2＋,Fe^3＋,Cl^-,SO4^2-,Mg^2＋,Na^＋,and HCO3^- etc. in the mother liquor. At the same time, the problem of evaporator scaling was solved basically by taking the measures of enhancing the reaction yield,improving evaporator equipment, adding chemical assistant and ameliorating technological conditions. The practice showed that the times of removing the scaling could be decreased to 2 - 3 times per year through the methods, which made the removing scaling more oversimplified and had good effect.