Equilibrium and mechanism studies of gold(Ⅰ)extraction from alkaline aurocyanide solution by using fluorine-free ionic liquids

• 作者: Ya-Ting Wang Men Liu Nian Tang Sheng-Jian Li Yan Sun Shi-Xiong Wang Xiang-Jun Yang
• 来源期刊: 稀有金属（英文版）
• 年，卷（期）: 2021,（7）
• 所属期刊栏目: ORIGINAL ARTICLES
• 页码范围: 1987-1994
• 页数: 8页
• 语种: 英文

摘要

Solvent extraction based on ionic liquids is generally considered to be an environmentally benign and effective technology for gold(Ⅰ)recovery.The aim of this work is to study gold(Ⅰ)extraction from aurocyanide solution using fluorine-free ionic liquids[A336][SCN],[A336][MTBA]and[A336][Mal].Various factors that affect gold(Ⅰ)extraction(including concentration of ionic liquids,equilibrium pH,concentration of the modifier tri-butyl phosphate(TBP),reaction time and initial concen-tration of gold in an aqueous solution)were studied and optimized.The results indicate that the three Aliquat 336-based ionic liquids all exhibit excellent behaviors for gold(Ⅰ)extraction.More than 99.8％ of gold(Ⅰ)can be extracted from the aqueous phase into the ionic liquid phase.The gold-loaded ionic liquids were characterized using infrared spectroscopy and mass spectrometry to study the extraction mechanism of gold(Ⅰ).The results revealed that extraction of gold(Ⅰ)into the ionic liquid phase was based on an exchange reaction between the anion Au(CN)2 in aqueous solution and the anion SCN-in ionic liquid[A336][SCN].The logarithmic relationship between dis-tribution coefficient and TBP concentration indicates that two TBP molecules are involved in the formation of the extracted complex.The extracted complex was determined to be A336+·Au(CN)2-.2TBP.In addition,the gold(Ⅰ)-loa-ded ionic liquids can be efficiently stripped using NH4SCN,2-methylthiobenzoic acid and methyl maltol.The results establish that Aliquat 336-based ionic liquids have potential application prospects in gold(Ⅰ)recovery from cyanide solutions.