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.
Abstract Aiming at salt lake brine with a high ratio of magnesium/lithium, extracting lithium was re- searched via the extractant tributyl phosphate （TBP） as well as the co-extraction reagent NaCIO4, and the effects of temperature, solution pH value, phase ratio, CIO4- 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 （ CIO： ）/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 compo- sition of extracted complex of Li＋ was close to 2LiCIO4- ·5TBP determined by the slope method at 25℃, and Li2CO3 was prepared by the strip liquor after demagnesium deeply.
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
2013年第1期55-60,共6页
Chemical Journal of Chinese Universities
基金
国家自然科学基金(批准号:21276215)
湖南省研究生科研创新项目(批准号:CX2010B267)资助
关键词
ClO-4
磷酸三丁酯
高镁卤水
锂镁分离
溶剂萃取
CIO4-
Tributyl phosphate
Brine with high Mg content
Li/Mg separation
Solvent extraction
