【摘要】 采用磷酸三丁酯(TBP)作为萃取剂、NaClO4作为共萃剂从高镁锂比盐湖卤水中提取锂,考察了萃取温度、溶液pH值、相比和ClO-4用量等因素对Li+萃取率的影响.结果表明,卤水一次萃取的最佳操作条件为:萃取时间10 min,温度25℃,Vo/Vw=2.0,n(ClO-4)/n(Li+)=2.0,pH=5～8,Li+和Mg2+的最高萃取率分别为65.41%和13.31%,锂镁分离系数达到12.32.用水在Vw/Vo=1.0、50℃时进行反相萃取,Li+的反萃率达到81.52%,此时镁锂质量比由45.61下降至8.45.锂镁离子萃取过程呈放热效应,金属离子的萃入对TBP中H的化学位移没有影响,但会导致P O双键的红外伸缩振动吸收峰从1280 cm-1移至1264 cm-1.25℃时用斜率法测定Li+萃合物的组成接近2LiClO4.5TBP,反萃液经深度除镁后可制备碳酸锂.更多还原

【Abstract】 Aiming at salt lake brine with a high ratio of magnesium/lithium,extracting lithium was researched via the extractant tributyl phosphate(TBP) as well as the co-extraction reagent NaClO4,and the effects of temperature,solution pH value,phase ratio,ClO-4 amount and other factors on Li+ extraction rate have been investigated in detail.The optimum operating conditions of a single extraction from brine are the following: the extraction time of 10 min,temperature of 25 ℃,Vo/Vw=2.0,n(ClO-4)/n(Li+)=2.0 and pH value in a range of 5—8.Under these conditions,the highest extraction rate for Li+ and Mg2+ was 65.41% and 13.31%,respectively,and the Li/Mg separation coefficient reached 12.32.Reversed phase extraction was carried out with water in Vw/Vo=1.0 and 50 ℃,the stripping rate of Li+ reached 81.52%,and the mass ratio of Mg/Li decreased from 45.61 to 8.45.The extraction process of Li+ and Mg2+ presented exothermic effect,metal ions extracted into the organic phase had no effect on the chemical shifts of H in TBP,but made the IR stretching vibration frequencies of P-O double bond shift to 1264 cm-1 from 1280 cm-1.The composition of extracted complex of Li+ was close to 2LiClO4·5TBP determined by the slope method at 25 ℃,and Li2CO3 was prepared by the strip liquor after demagnesium deeply.更多还原