| Using green, non-toxic, and inexpensive metallic iron as a capture agent, CaO-SiO2-MgO-Al2O3 quaternary slag system was selected to carry out pyrometallurgical enrichment of palladium, platinum, and rhodium in automotive failed catalysts. The single factor experimental method was used to study the effects of elemental iron form, type of iron oxide, amount of capture agent added, and melting time on the capture efficiency of palladium, platinum, and rhodium. The optimal process conditions are as follows: iron powder and iron oxide are preferred in the form of elemental iron, iron concentrate powder is selected, the amount of capturing agent added is 10%, the amount of reducing agent carbon powder is 5%, the melting temperature is 1500 ℃, and the melting insulation time is 90 min. After selecting the slag phase, the corresponding proportion of slag forming agent is added to reduce the melting point of the slag system and avoid the formation of Fe-Si alloy. The recovery rates of Pt, Pd and Rh are 98.92%, 99.81% and 98.21%, respectively. Good capture of Pt, Pd, and Rh by iron has been achieved, and an efficient process condition for recovering platinum group metals has been proposed. |
