摘要
以废汽车尾气净化催化剂铁捕集合金粉为研究对象,提出采用硫酸除铁-氯化浸出工艺回收Pt、Pd、Rh,主要考察了氯化浸出过程中盐酸浓度、温度、液固比、氧化剂用量、硝酸体积分数、反应时间等因素对铂族金属浸出率的影响.结果表明,在硫酸浓度3.2mol/L、反应温度70 ℃、溶解时间1h、液固比5mg/mL的条件下,铁合金粉的浸出渣率为14.37％,铂族金属溶解分散率低于0.5％;在HC1浓度8 mol/L、浸出温度90 ℃、液固比5 mg/mL、氯酸钠加入倍数2、搅拌速率300 r/min、硝酸体积分数10％、氯酸钠和硝酸氧化反应时间均为1h的最佳条件下,Pt、Pd、Rh的浸出率均大于99％.
Abstract
Taking the iron capture alloy powder of spent automobile exhaust purification catalyst as the research object,a process for separating and recovering Pt,Pd,and Rh was proposed,which adopted sulfuric acid for iron removal and chloride leaching.The effects of factors such as hydrochloric acid concentration,temperature,liquid-solid ratio,oxidant dosage,nitrate volume fraction,and reaction time on the leaching rate of platinum group metals during chloride leaching were mainly investigated.The results showed that under the conditions of sulfuric acid concentration for 3.2 mol/L,reaction temperature for 70 ℃,dissolution time for 1h,and liquid-solid ratio for 5 mg/mL,the leaching residue rate of iron capture alloy powder was 14.37％,and the dissolution rate of platinum group metals was less than 0.5％.Under the optimal conditions of HCl concentration for 8 mol/L,leaching temperature for 90 ℃,liquid-solid ratio for 5 mg/mL,sodium chlorate addition ratio for 2,stirring rate for 300r/min,nitric acid volume fraction for 10％,and oxidation reaction time of both sodium chlorate and nitric acid for 1 hour,the leaching rates of Pt,Pd,and Rh were all greater than 99％.
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