从堇青石型失效汽车尾气催化剂中富集铂族金属试验研究

Enrichment of Platinum Group Metals From Cordierite-type Automotive Exhaust Catalyst

研究了采用氢氟酸预处理—煅烧—加压碱浸工艺从堇青石型失效汽车尾气催化剂中富集铂族金属,考察了反应时间、碱用量、液固体积质量比、温度等对铂族金属富集率的影响。有效破坏失效催化剂堇青石(2MgO·2Al_2O_3·5SiO_2)的结构,可以释放其包裹的铂族金属,实现Pt、Pd、Rh的富集。差异化分离堇青石型失效催化剂中的Si/Al,可避免碱溶反应时钠硅渣(Na_2O·Al_2O_3·1.7SiO_2·2H_2O)的形成。试验结果表明,堇青石型失效催化剂预处理后,用质量浓度300g/L的氢氧化钠溶液浸出,控制液固体积质量比为8∶1,210℃下保温2h,Pt、Pd、Rh富集率可分别达310%、242%、240%。

Cordierite-type spent automobile exhaust catalyst was treated by pretreatment-calcination-pressurized alkali leaching process.The structure of cordierite(2MgO·2Al 2O 3·5SiO 2)was effectively destroyed and the platinum group metals encapsulating in it was released to achieve enrichment of Pt,Pd,Rh,and which can be provided for subsequent nickel matte smelting and recovery of Pt,Pd,Rh as the high quality raw materials.By differential separation of Si/Al from cordierite-type spent exhaust catalyst,the formation of sodium silicon slag(Na 2O·Al 2O 3·1.7SiO 2·2H 2O)was avoided.The effects of reaction time,hydrofluoric acid amount and liquid(mL)-to-solid(g)ratio on enrichment of Pt,Pd,Rh were examined.The results show that under the condition of sodium hydroxide concentration of 300 g/L,temperature of 210℃,reaction time of 2 h and liquid-to-solid ratio of 8∶1,the Pt,Pd,Rh enrichment rate can reach about 310%,242%and 240%,respectively.