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采用常规技术从原生资源中回收金的方法已在实践中经历了一个多世纪。目前,从这些资源中回收金的其他方法已引起注意。最近,通过精心制订的炭吸附和锌置换工艺,从稀释的碱性氰化液中回收金的方法已经完成,溶液萃取作为一种回收金的方案已引起关注。从电子工业废料和氰化电镀废液之类次生资源回收金是一门重要工艺。在工业上通常会碰到多种载金氰化液,包括浸出液,活性炭的洗出液和电镀废液,含金浓度为1～2000PPm。最近的研究成果表明,可以采用金的溶液萃取法,从这些碱性氰化液中回收金。此时,金以碱性阳离子—金氰化物离子对出现。烷基磷脂,诸如三—n—J基磷酸盐(TBP)和双—n—J基n—J基磷酸(DBBP),已用于酸性溶液中进行溶液萃取。TBP和DBBP二者对金的溶液萃取是有效的,并显示出较高的荷载能力。人们还注意到,这些萃取剂不仅有相当高的载金能力,而且有良好的选择特性。当反应不取决于PH值时,用酸或碱来脱除加入的有机萃取剂似乎是不可行的。因此,直接电解有机溶液以回收金,而省去传统的脱除工艺。
The method of recovering gold from primary sources using conventional techniques has been practiced for more than a century. At present, other methods of recovering gold from these resources have drawn attention. Recently, a method of recovering gold from a diluted alkaline cyanide solution has been completed through elaborate carbon adsorption and zinc substitution processes, and solution extraction as a method of recovering gold has attracted attention. Recovery of gold from secondary sources such as electronic industrial waste and cyanide electroplating waste is an important process. In the industry usually encountered a variety of gold-bearing cyanide solution, including leachate, activated carbon eluate and electroplating waste, the gold concentration of 1 ~ 2000PPm. Recent research shows that gold can be used to recover gold from these alkaline cyanide solutions. At this point, gold appears as a basic cation-gold cyanide ion pair. Alkyl phospholipids, such as tri-n-J-phosphate (TBP) and bis-n-J-based n-J phosphoric acid (DBBP), have been used for solution extraction in acidic solutions. Both TBP and DBBP are effective for gold solution extraction and show higher loading capacity. It is also noticed that these extractants not only have a fairly high gold-carrying capacity, but also have good selectivity characteristics. When the reaction is not dependent on the pH, it seems not feasible to remove the added organic extractant with an acid or base. Therefore, the organic solution is directly electrolyzed to recover the gold, eliminating the need for a conventional removal process.