Co-treatment of spent automotive catalyst and cyanide tailing via vitrification and smelting-collection process for platinum group metals recovery. Issue 5 (October 2021)

• Record Type: Journal Article
• Authors: Liu, Chuan; Sun, Shuchen; Tu, Ganfeng; Xiao, Faxin
• Is Part Of: Journal of environmental chemical engineering. Volume 9:Issue 5(2021)
• Publication Date: 2021-10
• Subjects: Recycling -- Hazardous solid waste -- Valuable metals -- High-temperature -- Clean slag -- Vitrification; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2021.105823
• Languages: English
• ISSNs: 2213-2929

Abstract

Abstract: In this study, a novel technology for the co-treatment of spent automotive catalyst (SAC) and cyanide tailing (CT) was proposed. The mixed waste material of SAC and CT were subjected to carbon thermal reduction-smelting with the addition of flux of CaO and Na2 B4 O7 . The platinum group metals (PGMs)-containing iron alloy (Fe-PGMs alloy) and the non-hazardous glass slag were successfully obtained. The optimum conditions for this technology are that the addition of CT, addition of reducing agent, addition of Na2 B4 O7, basicity, smelting temperature, and holding time for PGMs recovery rate was 30 wt%, 12 wt%, 5 wt%, 0.7–0.8, 1550 °C, and 60 min, respectively. Under these conditions, over 99% of PGMs can be recovered from the mixed waste materials and the content in the produced glass slag was below 5 g/t. Meanwhile, the total Fe content in obtained Fe-PGMs alloy was approximately 85% and its recovery was up to 90%. Furthermore, the mechanism was discussed, which can be divided into three processes: reduction and melting, migration and collection, and alloy formation. Besides, the results of the toxicity characteristics of glass slag indicated that heavy metal and the metalloid of arsenic (As) in the produced glass slag were successfully immobilized, which confirmed the produced glass slag can be taken as non-hazardous slag. Therefore, the co-treatment approach of SAC and CT proposed in this paper is an economical and environmentally friendly technology to recover the PGMs from SAC. Graphical Abstract: ga1 Highlights: Two types of hazardous solid waste of SAC and CT were simultaneously treated. More than 99% of PGMs can be extracted from SAC by co-treatment of SAC and CT. Iron was recovered from CT and simultaneously used as collector for PGMs recovery. The effects of various smelting parameters have been studied in detail. Glasslike slag was obtained from mixture of SAC and CT via vitrification.