分子识别分离碱性氰化液介质中铂、钯、铑及其机理研究

Separation and recovery of platinum, palladium and rhodium from alkaline cyanide solution is a hot topic in hydrometallurgy. Due to the low concentration of platinum, palladium and rhodium in ore cyanide solution, the solvent extraction need large quantities of solvents, even extraction equipment of high phase ratio(W/O) is used. The selectivity of ion exchange and activated carbon adsorption is low, and it is difficult to elute. Zinc powder replacement method need to destroy the cyanide solution, which caused environment pollution. In addition, the concentration of platinum, palladium and rhodium should not be too low. Therefore, the separation of platinum, palladium and rhodium from alkaline cyanide solution has not been reported. In this project, a new way to separate platinum, palladium and rhodium from alkaline cyanide solution by molecular recognition technology are selected. The optimization program of synthesis of molecular recognition stationary phase, determination of separating parameters，the recovery of platinum and palladium from the eluent.etc. will be determined in this study. A suitable process for the separation of platinum, palladium and rhodium from alkaline cyanide solution is being screened out. The process can be used for the separation and extraction of platinum, palladium and rhodium from the cyanide solution of the platinum palladium flotation concentrate and the recovery and utilization of platinum group metals from secondary resources. In addition, the mechanism of molecular recognition for separation of platinum, palladium and rhodium from alkaline cyanide solution will be systematically studied to enrich and develop the theories of extraction chemistry. This project not only has originality, but also has great theory significance and practical value.

从碱性氰化液中分离和回收铂、钯、铑是湿法冶金中的热点课题，溶剂萃取法因矿石氰化液中铂、钯、铑的浓度很低，即使采用适应W/O大相比的萃取设备，有机溶剂消耗仍然很大；离子交换和活性炭吸附选择性低，且难以洗脱；而锌粉置换法需破坏溶液中的氰根，环境污染大，且铂、钯、铑浓度不能太低，因此，从碱性氰化液中分离铂、钯、铑至今均未见实践报道。本项目另辟蹊径，研究采用分子识别技术从碱性氰化液中分离铂、钯、铑。项目将对分子识别固定相的制备、分离参数的确定、从洗脱液中回收铂、钯等方案进行优化，从中筛选出一种具有较好应用前景，从碱性氰化液中分子识别分离铂、钯、铑的最适宜工艺，可用于铂钯浮选精矿加压氰化液中铂、钯、铑的分离提取，及铂族金属二次资源的回收利用，并对分子识别分离碱性氰化液中铂、钯、铑的机理进行系统研究，丰富和发展萃取化学理论。本项目除具有原创性外，还具有重要的理论意义和实用价值。

从碱性氰化液中分离提取铂族金属一直是湿法冶金研究的一个热点，至今未见成熟的分离提取方案，本项目制备了系列具有分子识别功能的SuperLig®树脂，以SuperLig®树脂为吸附剂，采用分子识别技术从碱性氰化液介质中分离铂、钯、铑，对最大吸附容量、吸附平衡时间、最佳pH值、回收率、稳定性、洗脱剂种类等影响分子识别分离的主要技术参数进行了系统研究。所制备的系列SuperLig®树脂，单因素铂、钯分离回收率超过98.0%，富集倍数大于100倍，固定相重复使用次数高于50次。在此基础上，筛选出PS-BQP树脂，在pH值为10.5时，用于20L碱性氰化液中铂、钯、铑吸附分离，实验结果显示：铂、钯萃取回收率均>97.0%，铑回收率>92.0%，两步洗脱可完成铑与铂、钯的分离。通过光谱表征及密度泛函理论(DFT)计算,研究了SuperLig®树脂在碱性氰化溶液中对铂族金属的识别和分离机理，丰富和发展了铂族金属萃取化学理论。分子识别分离技术，可衔接“铂族金属加压氰化湿法新工艺”，为氰化浸出液中铂族金属的精炼分离提供了一种新方法。研究结果显示，分子识别分离工艺稳定性高，设备简单，操作方便，工艺连续,便于大规模生产和运用，由于有机溶剂使用量少，分子识别分离技术符合绿色冶金的要求，分子识别分离技术为碱性氰化液中低浓度铂族金属提取和分离提供了一种高效的新方法，在铂族金属矿山资源综合开发及二次资源回收领域具有广阔的应用前景。