十二烷基三甲基氯化铵从碱性氰化液中固相萃取金的研究

Solid Phase Extraction Gold from Alkaline Cyanide Solution with Dodecyl Trimethyl Ammonium Chloride

把一直应用于萃取有机物的固相萃取技术(SPE)用于萃取无机物金,研究了SPE与表面活性剂十二烷基三甲基氯化铵(DTMAC)液-液萃取(LLE)金两种技术,探索出一种从低浓度碱性氰化液中固相萃取金的最佳萃取条件。最佳萃取条件为:被萃液中DTMAC∶Au的摩尔比为1.5∶1.0;小柱须经过一定量0.01015 mol·L-1的DTMAC处理;萃取液pH为10.5;过柱流速为15 ml·min-1;C18,C8,C4,C24种填料柱对金的萃取容量都为4 mg,推荐使用C18小柱;乙醇为洗脱剂;洗脱流速为5 ml·min-1;萃取机制为:在碱性条件下DTMAC与Au(CN)-2能反应生成离子缔合物,该离子缔合物能被固相柱萃取富集;富集倍数高达500倍;选择性高;一次萃取率可超过98%,固相萃取柱不容易被破坏可重复使用。

The solid phase extraction（SPE） technique applied to the extraction of organic compounds was creatively used for the ex- traction of inorganic gold. The SPE and the liquid-liquid extraction（LLE） of the dodecyl trimethyl ammonium chloride （DTMAC） were investigated. The optimal conditions for extracting the trace amounts of gold from alkaline cyanide solution were explored. In that, the molar ratio of DTMAC to Au was 1.5： 1.0, the column should be pretreated by a certain amount of DTMAC with 0. 01015 mol＇L-1 , the pH of extraction was 10.5, the extracting flow rate was 15 ml .min -1, the extraction capacity of Cjs, Cs , C4, C2 column for gold all was 4 mg, C1s column was recommended to use, the ethanol acted as eluent, the flow rate of eluting was 5 ml.min-1 , the extraction mechanism was that, in alkaline solution, the surfactant （DTMAC） could react with Au （CN） 2- to form the ionic complex, which could be extracted and enriched by the solid phase extraction column; enrichment could achieve 500 times of the original; high selectivity; the recovery rate of gold was higher than 98%. The solid phase extraction column was not easily damaged and it could repeatedly use.