| 摘要 |
An improved process for recovery of precious metals such as gold or silver using novel ion exchnage resins having aryl guanidyl functionality from aryl guanidine compounds having a pKa at 25 DEG C less than 13 and preferably less than 12. The resins have improved elution properties compared to known guanidine reagents using caustic eluant solutions, particularly improved eluant solutions such as a mixture of sodium hydroxide and sodium benzoate. A selective elution of base metals may be carried out before elution of the precious metals from the resins having guanidyl functionality. |
