Page 209 - 《精细化工》2020年第12期

第 37 卷第 12 期 精 细 化 工 Vol.37, No.12
2020 年 12 月 FINE CHEMICALS Dec. 2020

水处理技术与环境保护
真空制盐中碳酸根离子的转化与阻垢防垢

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罗兴国，魏 昶，李兴彬 ，李永勇，郑三强，李 旻廷
（昆明理工大学 冶金与能源工程学院，云南 昆明 650093）

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摘要：针对盐硝联产工艺中成垢阴离子 CO 3 浓缩富集导致蒸发系统结垢问题，采用盐酸多段调节卤水 pH，使
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CO 3 转化为 HCO 3 ，有效地缓解了系统结垢，延长了生产周期。通过热力学计算、XRD、SEM-EDS 等方法探究
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了加酸过程中 CO 3 与 HCO 3 间的转化行为。结果表明，盐硝蒸发系统垢泥主要由 CaCO 3 垢和 Mg(OH) 2 垢组成，
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但结垢机理有所区别。盐系统结垢的诱因是，逐效富集的 Ca 随着温度的升高形成低溶解度的 CaCO 3 达到过饱
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和状态沉积析出形成垢层；硝系统结垢的主要原因是卤水中 CO 3 和 OH 的成倍富集。理论计算和实验结果指出，
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调节母液的 pH=9.0，可使少量的 CO 3 转化为 HCO 3 ；SEM-EDS 检测和垢泥的成分分析表明，调节母液 pH 至
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8.59 能使垢泥中的 Mg 有效溶解，部分 Ca 被溶解。未被溶解的 Ca 在卤水和换热管之间形成了一层较薄的垢
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层，避免了 pH 偏中性的卤水与换热管直接接触，在实现 CO 3 转化为 HCO 3 的同时，也在一定程度上抑制了换
热管的腐蚀进程。
关键词：真空制盐；阻垢防垢；碳酸根离子；碳酸氢根离子；腐蚀；水处理技术
中图分类号：X383 文献标识码：A 文章编号：1003-5214 (2020) 12-2571-07
Conversion of carbonate ions in vacuum salt production
and scale inhibition and prevention
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LUO Xingguo, WEI Chang, LI Xingbin , LI Yongyong, ZHENG Sanqiang, LI Minting
（Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093,
Yunnan, China）

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Abstract: In view of CO 3 concentration and enrichment in the co-production process of salt and nitrate,
which leads to scaling problems in the evaporation system, the study used multi-stage hydrochloric acid to
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adjust the brine pH to convert CO 3 to HCO 3 , alleviating system scaling and extending the production cycle
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effectively. The conversion behavior between CO 3 and HCO 3 during the acid addition process was
investigated by thermodynamic calculation, XRD and SEM-EDS. The results showed that the scale of the
salt and nitrate evaporation system was mainly composed of CaCO 3 scale and Mg(OH) 2 scale, but the
scaling mechanism was different. The cause of scale formation in the salt system was that with the increase
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of temperature, the Ca enriched would form CaCO 3 with low solubility. When CaCO 3 reached
supersaturated state, it would be deposited and precipitated out to form scale layer. While the main reason
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of scale formation in nitrate system was that the multiple enrichment of CO 3 and OH in brine. The
theoretical calculation and experimental results indicated that adjusting the pH of mother liquor to 9.0 could
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convert local CO 3 to HCO 3 . SEM-EDS and composition analysis of scale and sludge revealed that
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adjusting the pH of brine to 8.59 could effectively dissolve Mg in scale and sludge, and part of Ca . The
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undissolved Ca formed a thin scale layer between the brine and the heat exchanger, avoiding the brine
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with a neutral pH to be in direct contact with the heat exchanger and realizing the conversion of CO 3 to
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HCO 3 . At the same time, the corrosion process of heat exchange tube was restrained to some extent.
Key words: vacuum salt making; scale inhibition and prevention; carbonate ions; bicarbonate ions; corrosion;
water treatment technology

收稿日期：2020-05-19; 定用日期：2020-07-01; DOI: 10.13550/j.jxhg.20200420
基金项目：云南省科技计划科技入滇专项（20181B030）；昆明市科技计划重点项目（2018-1-H-17215）
作者简介：罗兴国（1992—），男，博士生，E-mail：1475697675@qq.com。联系人：李兴彬（1984—），男，教授，E-mail：lixingbin2011@
126.com。