混合醇萃取剂从浓缩盐湖卤水中萃取提硼的实验研究

摘要

Boron was extracted from the concentrated brine from a sulfate-type salt lake by 2-ethyl-1,3-haxanediol and isobutyl alcohol as mixed extractant (by a certain volume ratio),and aviation kerosene as diluting agent.The experimental conditions including the concentration of extractant,pH of concentrated salt lake brines,exraction phase ratio (O/A),extraction temperature,extraction time,saturated extraction capacity,concentration of stripping agent,and back-extraction phase ratio etc.were investigated.Results showed that the optimal conditions were as follows,the volume ratio of 2-ethyl-l,3-haxanediol,isobutyl alcohol,and aviation kerosene was 1∶2∶3,pH =3,extraction phase ratio (O/A) was 1 ∶ 1,reaction temperature was 20 ℃,and extraction time was 5 min.At the back extraction stage,with 0.25 mol/L sodium hydroxide solution as stripping agent,1:2 of volume ratio of stripping agent and organic phase,15 min back-extraction time,and reaction temperature at 30 ℃.After 3 extraction and back-extraction series process,boron concentration of extraction raffinate was 0.8 mg/L,the extraction and back-extraction rate were 99.99％ and 99.78％,respectively,and the recovery of boron in the concentrated brines was about 99.77％.%以2-乙基-1,3-己二醇和异丁醇按照一定体积比组成混合萃取剂、航空煤油为稀释剂,萃取某硫酸盐型盐湖浓缩卤水中的硼.对萃取剂浓度、浓缩卤水pH、萃取相比、萃取温度、萃取时间、饱和萃取容量和反萃剂浓度、反萃相比等进行了实验研究.结果表明:2-乙基-1,3-己二醇、异丁醇和航空煤油体积比为1∶2∶3,卤水pH为3,萃取相比为1:1,温度为20℃,萃取时间为5 min;将得到的富硼有机相用0.25 mol/L氢氧化钠溶液进行反萃,反萃相比为1∶2、温度为30℃、反萃取时间为15 min.经三级萃取及反萃,卤水中硼质量浓度降为0.8 mg/L,硼萃取率为99.99％,反萃率为99.78％,硼回收率为99.77％,萃取效果好.