Pt and Rh Recovery from Waste: Catalytic Converters

摘要

The research was conducted to determine optimum conditions to recover precious metals from auto catalytic converter. The catalytic converters used in this study contained Pt and Rh. The recovery process involved leaching, solvent extraction process, stripping. Hydrochloric acid was used to leach the metals from the catalytic converters. The solvent extraction was carried out at room temperature using trioctyl amine (TOA) in toluene as extracting solution. Hydrochloric acid and nitric acid were used in stripping study. The atomic absorption spectrophotometer was used to measure the amount of metals recovered under various conditions such as leaching acid concentration, leaching temperature, extracting agent concentration, stripping agent. The results showed that 87.6 % of rhodium, and 98.5 % of platinum were leached from the catalytic converter. Extraction of platinum using 2-3 wt% TOA in toluene was found nearly complete, while rhodium was only extracted in trace amount. Stripping of platinum from organic solution was carried out using equivolume of acid (nitric or hydrochloric) and metal-loaded organic solutions. Platinum was completely stripped out using 8 M nitric acid at 50℃.