酸化冷冻法从提钾母液中提取硼酸的最佳工艺

Optimal Process of Extracting Boric Acid through Acidification and Refrigeration from Mother Liquor after Potassium Extraction

针对柴达木盆地某盐湖提钾后母液,以0,℃和25,℃H3BO3–MgCl2–H2O体系相图为指导,研究了酸化–冷冻提取硼酸工艺的pH、冷冻温度、冷冻时间对硼酸回收率的影响,获得老卤酸化提取硼酸的最佳工艺条件:VHCl∶V卤水=4∶125,0,℃冷冻时间3,h.结果表明,干燥后的粗产品硼酸纯度为87.3%,单次循环硼酸回收率在75%以上,经重结晶后硼酸纯度可达99%以上.

Based on the phase diagram of the system （H3BO3-MgC12-H20） at 0℃ and 25 ℃, the effect ofpH, freezing tem- perature, and freezing time were investigated in order to recover boron from the mother liquor brine in Qaidam Basin after potassium extraction. A series of operating conditions including acidizing, freezing and separating has been studied, and the optimum conditions were obtained with VHCJ ： Vbrines = 4 ： 125, and 3 h freezing time at 0 ~C. The results showed that the purity of the drying boric acid reached 87.3% after raw product was dried, boron at one single recycling recovery was more than 75%, and the purity of the boron acid reached 99% after re-crystallization.