盐湖卤水蒸发浓缩过程中pH值变化规律研究

pH Value Change Trends in Salt Brine Evaporation

实验测定了当雄错、一里坪和多格错仁3个盐湖卤水蒸发浓缩过程中pH值,结果发现卤水浓缩过程中pH值表现趋酸向变化或越碱向变化规律;卤水中氯化钠、硫酸钠和水等大量中性成分随浓缩进行不断减少,则强酸弱碱盐或强碱弱酸盐在体系中所占比例越来越大,其水解推动pH值规律性变化;上述3个盐湖卤水浓缩时pH值变化试验数据反映的规律表明,据卤水化学组成配盐结果,可预先判断浓缩过程中pH值变化趋向;氯化物型和硫酸镁亚型盐湖卤水蒸发浓缩时pH值表现逐渐下降的规律,碱金属的碳酸盐或硼酸盐占较大比例的盐湖卤水蒸发浓缩时pH值表现逐渐上升规律;卤水浓缩过程中pH值变化规律对盐湖资源开发研究具有指导作用。

The pH value changes during the evaporation of brines were determined for three salt lakes,namely,Dangxiongcuo,Yiliping and Dogai Coring.The results show that pH value changes during brine evaporation exhibits a rule of either acidification trend or alkalization trend.And with gradually decrease of massive neutral compositions as sodium chloride,sodium sulfate and water,the proportion of strong acid-weak base salts or strong base-weak acid salts become increasingly greater,and then the hydrolysis of these salts make the pH of the brine systems change regularly.The pH value change trends of these three salt brines indicated that the pH value changing trend during brine evaporation can be pre-judged according to the salt-marching result of the brine composition.The conclusions are that the pH values present a decreasing trend for evaporation of chloride type and magnesium sulfate subtype salt brines,an increasing trend for that of salt brines which account for large proportion of alkali metal carbonate and borate.