Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing, 100083, China.
Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing, 100083, China; Shunde Innovation Institute, University of Science and Technology Beijing, Foshan, 528399, China; Institute of Engineering Technology, Sinopec Catalyst Co., Ltd., Beijing, 101111, China.
J Environ Manage. 2024 May;358:120847. doi: 10.1016/j.jenvman.2024.120847. Epub 2024 Apr 15.
Platinum group metals (PGMs) are strategic metals. Auto-exhaust catalysts are their main application fields. The recovery of PGMs from spent auto-exhaust catalysts has remarkable economic value and strategic significance. Aiming at the problems of ferrosilicon generation for Fe capturing and subsequent oxygen blowing to remove iron with high energy consumption and heat release, a technology of Fe-Sn synergistic capturing PGMs was proposed. Taking full the advantage of the lower melting point of Fe-Sn alloy (<1200 °C) and its unique affinity for PGMs, the PGMs were captured at approximate 1400 °C with Fe-Sn as the collector. In experiment, 500 g of spent auto-exhaust catalysts were employed to minimize error and approximate industrial production. The mechanism of Fe-Sn synergistic capturing PGMs was elucidated. The generation of Fe-Sn-PGMs alloy lowered the activity of [PGMs] in the system, accelerated the reduction of the PGMs oxides and promoted the alloying of [PGMs]. Therefore, Fe-Sn synergistic capturing PGMs was realized. The inability of Si to enter the alloy phase was confirmed by theoretical calculations, avoiding the generation of ferrosilicon. The effects of basicity, CaF, m(Fe)/m(Sn) and the amount of collector on capturing PGMs were optimized. Under the optimized conditions (basicity R = 1.1, spent auto-exhaust catalysts 70 wt%, CaO 30 wt%, BO 10 wt%, CaF 7 wt%, m(Fe)/m(Sn) = 1/1 and the collector 15 wt%), the content of PGMs in the slag phase was 2.46 g/t. It is feasible to remove Fe and Sn by oxidation to achieve the purpose of PGMs enrichment. This technology offers guidance on the safe, environmentally sound, and efficient disposal of spent auto-exhaust catalysts, promoting the sustainable development of PGMs.
铂族金属（PGMs）是战略金属。汽车尾气催化剂是其主要应用领域。从废汽车尾气催化剂中回收 PGMs 具有显著的经济价值和战略意义。针对 Fe 捕集用硅铁生成和后续氧吹除铁高能耗、高放热量的问题，提出了 Fe-Sn 协同捕集 PGMs 技术。充分利用 Fe-Sn 合金（<1200°C）的低熔点和其对 PGMs 的独特亲和力，在约 1400°C 下用 Fe-Sn 作为捕集剂捕集 PGMs。在实验中，采用 500g 废汽车尾气催化剂以最小化误差并接近工业生产。阐明了 Fe-Sn 协同捕集 PGMs 的机理。Fe-Sn-PGMs 合金的生成降低了体系中[PGMs]的活性，加速了 PGMs 氧化物的还原，促进了合金化。因此，实现了 Fe-Sn 协同捕集 PGMs。理论计算证实了 Si 无法进入合金相，避免了硅铁的生成。优化了碱度、CaF、m(Fe)/m(Sn)和捕集剂用量对捕集 PGMs 的影响。在优化条件下（碱度 R=1.1，废汽车尾气催化剂 70wt%，CaO 30wt%，BO 10wt%，CaF 7wt%，m(Fe)/m(Sn)=1/1，捕集剂 15wt%），渣相中 PGMs 的含量为 2.46g/t。通过氧化去除 Fe 和 Sn 以达到 PGMs 富集的目的是可行的。该技术为废汽车尾气催化剂的安全、环保、高效处置提供了指导，促进了 PGMs 的可持续发展。
