从江陵凹陷富钾地下卤水中提取硼酸

江陵凹陷地下卤水资源丰富，w（氯化钠）=23.3%、w（氯化钾）=1.4%、ρ（氧化硼）=2.48 g/L，均为工业品位的2倍以上。根据卤水中氯化钠浓度接近饱和的特征，通过蒸发析钠以浓缩富集硼，确定了最佳的浓缩倍数为4.0，氧化硼质量浓度由2.48 g/L富集到9.84 g/L；采用溶剂萃取法分离硼，在最佳条件下，单级萃取率为96.73%，反萃取率为98.81%；富硼反萃液经蒸发浓缩、酸化沉淀制取硼酸产品，其质量达到国家标准GB/T 538—2006《工业硼酸》的一等品指标要求，硼的总收率为82.63%。

Extraction of boric acid from potassium-rich underground brine in Jiangling Depression

The underground brine in Jiangling Depression is rich in a variety of resources.The concentrations of sodium chloride，potassium chloride，and boron trioxide in the brine are 23.3%（mass fraction），1.4%（mass fraction），and 2.48 g/L，respectively，which are more than two times of their industrial grade.According to the characteristics of  sodium chloride in brine close to its saturation degree，boron trioxide enriched from 2.48 g/L to 9.84 g/L at the best concentration multiple of four times by the precipitation of sodium chloride through evaporation.Then，boron was separated by solvent extraction method， with the single-stage extraction yield of 96.73% and the stripping efficiency of 98.81%.Boric acid product was prepared by the evaporation and acidification to the strip liquor， with its quality achieving the requirements for the first class of Industrial Boric Acid，GB/T 538—2006.The total recovery fraction of boron was 82.63%.