从废钯催化剂中回收钯的绿色工艺研究

The study on the green Pd-recovery process from waste Pd catalysts

以双氧水-盐酸混合溶液浸出废催化剂中钯，经离子交换树脂脱出氯钯酸后，循环使用；pH8-9的氢氧化钠和氯化铵溶液为洗脱液。研究了双氧水、盐酸浓度、浸出温度和时间及浸出液循环次数对浸出率的影响，结果表明，最佳浸出条件为：盐酸、双氧水的浓度分别为：1．7，1．1moL／L，72℃反应7h，80℃反应2h，钯平均浸出率98．3％，单程总回收率90.2％；由于浸出液与洗脱液能循环使用，解决了浸出液深度脱钯问题，并避免排放大量废酸液，实现了绿色化生产。

The mixed H2O2 - HCl solutions were used to leach Pd from waste Pd catalysts, and could be recycled when the H2PdCl6 was eluated from leaching solutions by ion- exchange ,the mixed NaOH -NH4Cl（ pH 8 - 9） used as eluant. The effects of concentrations of H2O2 , and HCl solutions,leaching temperature and time, and recycle frequency of leaching solutions on the extraction rate of Pd were investigated. The results showed that the optimum leaching condition was 1.7 mol/L HCl,1.1 mol/L H2O2 , extracting temperature at 72 ℃ for 7 h, and then 80 ℃ for 2 h. The average extraction rate was 98.3%, and one - way total yield 90.2%. Because of the recycling of leaching solutions and eluants ,the deeply - extracted Pd problems from loaching solution can be solved, and the discharge of large quantities of waste acid solutions can be avoided. Therefore, a novel green Pd - recovery process is established.