酸沉-萃取-结晶法从高镁卤水中提取硼酸的工艺研究

Research on extracting boric acid from high magnesium brines by combined process of acidification precipitation-centrifugal solvent extraction-dissolution crystallization

以东台吉乃尔盐湖冬季产出浓缩卤水为原料,进行了酸沉-萃取-结晶法从高镁卤水中提取硼酸的工艺研究。研究表明,此工艺能完全分离提取卤水中的硼。其中,酸化沉淀的关键是根据不同原料确定加酸量;离心萃取阶段选定25%（体积分数）异辛醇＋25%异戊醇＋50%磺化煤油组成萃取体系,p H为1.5~2.0,相比（O/A）为2∶1,离心萃取机转速为2 400 r/min,萃取级数为3,萃取率可达97.3%,三级反萃后萃取率达99%。反萃液热溶粗硼酸冷却结晶制备了99.8%的高纯硼酸。

A study for extracting boric acid from high magnesium brines by a combined process incorporating acidic precipitation,centrifugal solvent extraction,and dissolution crystallization was performed using highly concentrated winter brine from the East Taijinar Salt Lake as feedstock.It was found that this process was capable of extracting boron from the brine in a thorough manner.For this purpose,the key to acidic precipitation was to manipulate acid dosage as per the boron level in the raw material.Centrifugal extraction was carried out using 25%（volume fraction） isooctanol＋25% isoamyl alcohol＋50% sulfonated kerosene as the organic system,at p H was 1.5~2.0,O/A ratio was 2∶1,and centrifuge rotation speed was 2 400 r/min;after 3 stages of extraction and stripping,the extraction rate achieved 97.3% while stripping attained 99%.The resulting stripped liquor was used for dissolving the crude boric acid obtained from acidic precipitation whereby 99.8% high purity boric acid was produced after cooling crystallization.