低浓度含铑有机废催化剂回收铑的工艺研究

Study on the Process of Recovering Rhodium from Low-concentration Rhodium-containing Organic Waste Catalysts

含铑有机催化剂在有机催化过程的氢化、羰基加成、酰氢化等反应中极具活性,但在催化过程中,各种高沸点的副产物及其原料杂质使催化剂失去活性。失活的铑催化剂含铑量较低,但远高于矿石含量,是重要的铑二次资源,从废催化剂中回收铑意义重大。研究表明,低浓度含铑有机废催化剂经酸化-氧化后,采用络合沉铑-尾液置换试验富集铑,络合沉淀试验中加入草酸+甲酸混合液40 mL,草酸∶甲酸(体积比)为1.2∶1.0时,在70 ℃温度下反应60 min,铑回收率可达95.01%;络合沉铑后尾液采用铝置换回收铑,反应温度为80 ℃,初始酸度调节至2 mol/L,反应24 h后,铑沉淀率可达54.19%。

Rhodium-containing organocatalysts are very active in reactions such as hydrogenation,carbonyl addition,and acyl hydrogenation in organic catalysis processes,but in the catalysis process,various high-boiling by-products and their raw material impurities make the catalyst inactive.The deactivated rhodium catalyst has a lower rhodium content,but is much higher than the ore content,and is an important secondary rhodium resource,and it is of great significance to recover rhodium from spent catalysts.The research shows that after acidification-oxidation of low-concentration rhodium-containing organic waste catalysts,rhodium is enriched by complex precipitation rhodium-tail liquid replacement test,and 40 mL of CHO+HCOOH mixed solution is added to the complex precipitation test,when CHO∶HCOOH(volume ratio) is 1.2∶1.0,the rhodium recovery rate can reach 95.01% after reaction at 70 ℃ for 60 min;the tail liquid after complexation and precipitation of rhodium is replaced by aluminum to recover rhodium,the reaction temperature is 80 ℃,the initial acidity is adjusted to 2 mol/L,and the rhodium precipitation rate can reach 54.19% after 24 h of reaction.