摘要：

根据硫酸钠、氯化钠和硝酸钠溶解度曲线及Na⁺//Cl^-、SO₄^2--H₂O三元水盐体系相图，制定了分盐结晶工艺方案，考察了一次蒸发率、冷冻温度、二次蒸发率等参数对分离效果的影响。实验结果表明：控制一次蒸发率为68%，冷冻温度为-5℃，二次蒸发率为70%，采用本方案得到了纯度为96.7%的硫酸钠、94.3%的氯化钠和98.4%的硝酸钠，产品都达到工业标准，解决了杂盐危废问题，消除了二次污染，真正实现了盐的资源化利用。

关键词: 煤化工废水, 水盐体系, 分盐结晶, 资源化利用

Abstract:

According to the solubility curves of sodium sulfate, sodium chloride and sodium nitrate and the phase diagram of Na⁺//Cl^- and SO₄^2--H₂O ternary water-salt system, a salt separation crystallization process scheme was established. The effects of parameters such as primary evaporation rate, secondary evaporation rate and freezing temperature on the separation effect were investigated. Experimental results showed that when the primary evaporation rate was controlled at 68%, the freezing temperature was -5℃, and the secondary evaporation rate was 70%, the separation purities of sodium sulfate, sodium chloride and sodium nitrate reached 96.7%, 94.3% and 98.4%, respectively, which all meet industrial standards. Therefore, this study solves the problem of hazardous salt waste, eliminates secondary pollution, and truly realizes the resource utilization of salt.

Key words: coal chemical wastewater, water-salt system, crystallization process of salt separation, resource utilization

中图分类号: 

• X703.1