Recovery of platinum and synthesis of glass-ceramic from spent automotive catalyst via co-treatment process with coal fly ash

Spent automotive catalyst (SAC) has attracted attention because of containing platinum group metals (PGMs) along with hazardous materials such as heavy metals and organic substances. In this work, a new process was proposed to recover platinum in SAC and simultaneously prepare glass-ceramics by co-treatment process with coal fly ash (CFA). The experimental results indicated that platinum can be highly recovered and that glass-ceramics can also be successfully prepared. The maximum platinum recovery was approximately 99% when the optimum CFA addition, iron collector addition, and CaO/SiO2 mass ratio were 30-50 wt%, 5 wt%, and 0.7-0.8, respectively, at 1550 degrees C for 60 min. Under these optimal conditions, the enrichment coefficient of platinum was approximately 4.2, and the platinum content in the obtained glassy slag was below 4 g/t. Meanwhile, the results of the leaching efficiency of heavy metals in glassy slag showed that the obtained glassy slag is a harmless residue. Moreover, an economic evaluation was also carried out by comparing other metal collection processes. Furthermore, the synthesis of glass-ceramics by a one-step heat-treatment process further confirmed that this proposed approach was an economical and promising method for recycling platinum from SAC and reutilizing of CFA.