废碳载钯催化剂回收钯工艺研究

摘要

以废碳载钯催化剂为研究对象,经过焙烧、还原后采用盐酸-双氧水体系浸出,从浸出液中提纯得到海绵钯,对焙烧及浸出工艺条件对钯浸出率影响进行了研究.结果表明,随着焙烧温度、焙烧时间、水合肼用量、盐酸用量、双氧水用量的增大,钯浸出率先增大后减小.对0.5 g废催化剂样品,其适宜的焙烧条件为600℃焙烧30 min,还原剂为0.1 mL水合肼,以2 mL盐酸、0.2 mL双氧水为浸出剂,钯的累计浸出率为99.72％.表征分析结果显示,焙砂主要为球状颗粒物,原料中由活性炭为主要成分的块状和棒状物基本消失;焙砂主要含有钯、二氧化硅、硫酸钙和氧化钯,其中钯含量由2％提高到18.26％.%The waste carbon-supported palladium catalyst was used as the recycling object.The waste was roasted,and then leached in a mixed solution containing hydrochloric acid and hydrogen peroxide,and palladium was recovered from the leaching solution.The effects of the roasting and leaching conditions on the palladium leaching rate were investigated.The results showed that palladium leaching rate rose first and then declined with the increase of calcination temperature,calcination time,and the dosage of hydrazine hydrate,HCl and H2O2.For 0.5 g waste catalyst sample,the roasting was carried out first at 600℃ for 30 min,and then palladium was leached out in a solution of 2 mL HCl and 0.2 mL H2O2,and finally was reduced by 0.1 mL hydrazine hydrate.Under these conditions,the total palladium leaching rate reached up to 99.72％.The characterization results showed that the calcine,mainly consisting of silica,calcium sulfate,palladium and palladium oxide,was in the shape of spherical particles.Palladium content was increased to 18.26％from 2％in the waste.The block and rodlike particles,two main components in the calcine of activated carbon,had vanished.