盐析法由卤水制备纯碱的新工艺

New process for producing soda ash from brine by salting-out method

卤水与碳酸氢铵反应生成碳酸氢钠结晶和氯化铵溶液，碳酸氢钠的结晶率是70％-79％。为了提高碳酸氢钠的结晶率，研究了采用加入盐析剂的方法，通过盐析剂的盐析作用，使碳酸氢钠的溶解度降低，从而更多地结晶析出。实验确定选择高沸点的盐析剂D，使结晶率提高到90％以上。通过正交试验研究，得到盐析法的适宜工艺条件：盐析剂与氯化钠物质的量比为1．0：1．0，反应温度35℃，碳酸氢铵与氯化钠的物质的量比为1．0：1．0，反应时间120min。

In the process of preparation of sodium bicarbonate crystal and ammonium chloride solution from brine and ammonium bicarbonate, the crystallization rate of sodium bicarbonate is between 70% -79% in general. In order to improve the crystallization rate of sodium bicarbonate, the method of adding salting - out agent was studied. The salting - out effect of salting - out agent would make the solubility of sodium bicarbonate decrease and more crystal of sodium bicarbonate would be seperated out. The salting - out agent D with high boiling point was determined through experiments, and the crystallization rate of sodium bicarbonate could be increased to 90% above. Through orthogonal test,the suitahle technological conditions of salting out method have been obtained, amount - of - substance ratio of salting - out agent to sodium chloride was 1.0： 1.0,reaction temperature was 35 ℃ ,amount- of -substance ratio of ammonium bicarbonate to sodium chloride was 1.0：1.0 and reaction time was 120 min.