An integrated capture of copper scrap and electrodeposition process to enrich and prepare pure palladium for recycling of spent catalyst from automobile

摘要

The coordinated treatment for two kinds of waste is an effective way to save energy and improve the recovery efficiency of resource. In worldwide, more than half of palladium is used to produce catalysts in automobile. However, with the increasing consumption of palladium, the scarcity of palladium resource is becoming prominent. This paper proposed an integrated process based on capture of copper scrap and electrodeposition process to recycle palladium in spent catalysis from automobile. The technological process mainly consisted of two procedures: capture of copper scrap with the purposes of enriching palladium and electrodeposition process with the purposes of separating and purifying palladium. Several highlights were summarized as follows: (ⅰ) a capture mechanism of palladium by copper scrap was studied by the calculation of surface thermodynamics and first principles, (ⅱ) Optimum designs, parameter and product analysis were developed to guide industrial recycling. The appropriate parameters for capture of copper scrap are the melting temperature reached 1400 °C, adding 20% dosage of copper scrap and 2 of mass ratio of SiO_2/Al_2O_3 and for the electrodeposition process, nearly 100% of palladium was deposited on the cathode under 0.1 M concentration of HNO_3, -0.042 V of electrodeposition potential and 25 °C reaction temperature with 9 h. (ⅲ) This process overcame the shortages of traditional process and showed its efficiency and environmental performance. This study is significant for high-efficient, low-cost and environment-friendly recycling of valuable resource in spent catalysis from automobile.