湿法炼锌高盐废水的综合回收实验研究

Study on the recovery of high salinity wastewater from zinc hydrometallurgy process

采用"预处理除杂—蒸发—盐分离结晶"技术对锌烟尘处理厂产出的高盐废水进行了探索实验研究.结果表明:采用该技术处理锌冶炼高盐废水,分别得到合格生产用水、无水硫酸钠和氯化钠,高盐废水实现了资源化回收利用.中和后的浓盐水加热到95~100℃进行高温蒸发浓缩,分离得到结晶盐无水硫酸钠,含量为98.79%,达到Ⅱ类优等品质量标准;蒸发得到的冷凝水电导率≤48μS/cm,水质达到生产用水标准.高温蒸发后期,氯化钠富集在少量的残余液中,保持60℃低温蒸发,分离得到结晶盐氯化钠,其中氯化钠含量为93.82%.

In this paper, the experimental study on recovering high salinity wastewater from zinc oxide dust industry was carried out by the combination technology of ＂pretreatment for separating impurities—evaporation—salinity separation and crystallization＂. By adopting this technique, the results showed that the qualified production water, anhydrous sodium sulfate and sodium chloride were recovered respectively from the high salinity wastewater. The high salinity wastewater was recycled completely. After evaporation and concentration at high temperature（95～100℃）, the anhydrous sodium sulfate was crystallized from the neutralized wastewater, and the content was 98.79%, which reached to the quality standard of anhydrous sodium sulfate. The electric conductivity of condensed water obtainedⅡ by evaporation is less than 48μS/cm, which reached to the standard of production water. At the last period of high temperature evaporation, the sodium chloride was concentrated in residual liquid. Then sodium chloride was crystallized when keep evaporating at low temperature（60℃）, which was comprised of 83.82% NaCl.