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, (Fe)/(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%, (Fe)/(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.

中文翻译：

---

Fe-Sn协同捕获铂族金属的优化及其机理

铂族金属（PGM）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铂族金属具有显着的经济价值和战略意义。针对硅铁生成捕铁及后续吹氧除铁能耗高、放热高的问题，提出了Fe-Sn协同捕集铂族金属技术。充分利用Fe-Sn合金较低的熔点（<1200℃）及其对铂族金属的独特亲和力，以Fe-Sn作为捕收剂在约1400℃下捕获铂族金属。在实验中，使用了 500 克废汽车尾气催化剂，以尽量减少误差并近似工业生产。阐明了 Fe-Sn 协同捕获铂族金属的机制。 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[PGMs]的合金化。因此，实现了Fe-Sn协同捕获铂族金属。通过理论计算证实Si无法进入合金相，避免了硅铁的生成。优化了碱度、CaF、(Fe)/(Sn) 和捕收剂用量对捕获铂族金属的影响。优化条件下（碱度R = 1.1，废自排气催化剂70 wt%，CaO 30 wt%，BO 10 wt%，CaF 7 wt%，(Fe)/(Sn) = 1/1，捕收剂15 wt%） %)，渣相中PGMs含量为2.46 g/t。通过氧化去除Fe、Sn达到富集PGMs的目的是可行的。该技术为汽车尾气废催化剂的安全、环保、高效处理提供了指导，促进了铂族金属的可持续发展。