Separation of Pd and Pt from highly acidic leach liquor of spent automobile catalysts with monothio-Cyanex 272 and trioctylamine

Platinum group metals(PGMs),especially Pd,Pt,and Rh,have drawn great attention due to their unique features.Direct separation of Pd and Pt from highly acidic automobile catalyst leach liquors is disturbed by various factors.This work investigates the effect of various parameters including the acidity,extractant concentration,phase ratio A/O,and diluents on the Pd and Pt extraction and their stripping behaviors.The results show that the Pd and Pt are successfully separated from simulated leach liquor of spent automobile catalysts with monothioCyanex 272 and trioctylamine(TOA).Monothio-Cyanex 272 shows strong extractability and specific selectivity for Pd,and only one single stage is needed to recover more than 99.9% of Pd,leaving behind all the Pt,Rh,and base metals of Fe,Mg,Ce,Ni,Cu,and Co in the raffinate.The loaded Pd is efficiently stripped by acidic thiourea solutions.TOA shows strong extractability for Pt and Fe at acidity of 6 mol·L^(–1) HCl.More than 99.9% of Pt and all of the Fe are extracted into the organic phase after two stages of countercurrent extraction.Diluted HCl easily scrubs the loaded base metals(Fe,Cu,and Co).The loaded Pt is efficiently stripped by 1.0 mol·L^(–1) thiourea and 0.05–0.1 mol·L^(–1) Na OH solutions.Monothio-Cyanex 272 and TOA can realize the separation of Pd and Pt from highly acidic leach liquor of spent automobile catalysts.

Pd(111)与Pt(111)上NO氧化的第一性原理研究

随着排放法规的日益严格,发动机的氮氧化物(NO_(x))后处理已成为当今研究的重点问题.针对目前可有效降低稀燃汽油机NO_(x)的稀燃氮氧化物捕集器中铂(Pt)和钯(Pd)两种贵金属之间的替换问题,进行了密度泛函理论(density functional theory,DFT)计算研究.首先,对一氧化氮(NO)、氧气(O_(2))、二氧化氮(NO_(2))在两种催化剂(111)表面的吸附进行了研究,之后,在两催化剂表面对比研究了氧化过程中涉及的O_(2)解离与NO氧化两反应过程,揭示了NO在Pd与Pt催化剂上的氧化机理.结果显示:3种物质在催化剂表面的吸附强度为NO>O_(2)>NO_(2).氧覆盖度将会改变氮氧化物的最佳吸附构型,随着表面氧原子的增加NO会由三重空位式吸附转变为顶点吸附,NO_(2)会由μ-N,O-亚硝基吸附转变为硝基吸附.在O_(2)解离过程中Pt的催化能力优于Pd,但是两者对NO氧化的催化能力接近.在Pd和Pt表面反应限速步骤都是O_(2)的解离,Pd对O_(2)较弱的解离能力导致了其NO的转化效率低于Pt.氧覆盖度对氧化过程存在影响,通过电子结构分析发现,氧覆盖度的提升使催化剂与吸附物质之间的吸附能下降,这导致了反应由吸热变为放热,使催化可以自发进行.反应生成的NO_(2)需要1.00 eV以上的能量完成脱附,这在原子层面解释了NO_(2)对NO氧化反应的抑制作用.

Solar-assisted selective separation and recovery of precious group metals from deactivated air purification catalysts

The mitigation of environmental and energy crises could be advanced by reclaiming platinum group precious metals(PGMs) from decommissioned air purification catalysts. However, the complexity of catalyst composition and the high chemical inertness of PGMs significantly impede this process. Consequently,recovering PGMs from used industrial catalysts is crucial and challenging. This study delves into an environmentally friendly approach to selectively recover PGMs from commercial air purifiers using photocatalytic redox technology. Our investigation focuses on devising a comprehensive strategy for treating three-way catalysts employed in automotive exhaust treatment. By meticulously pretreating and modifying reaction conditions, we achieved noteworthy results, completely dissolving and separating rhodium(Rh), palladium(Pd), and platinum(Pt) within a 12-h time frame. Importantly, the solubility selectivity persists despite the remarkably similar physicochemical properties of Rh, Pd, and Pt. To bolster the environmental sustainability of our method, we harness sunlight as the energy source to activate the photocatalysts, facilitating the complete dissolution of precious metals under natural light irradiation. This ecofriendly recovery approach demonstrated on commercial air purifiers, exhibits promise for broader application to a diverse range of deactivated air purification catalysts, potentially enabling implementation on a large scale.

从含钌废料中回收钌的研究进展

从铂族金属废料中回收再利用钌对于实现行业可持续发展、节约资源和环境保护都有着重大影响。钌废料一般包括含钌废催化剂、含钌合金材料、含钌核废料和其他含钌废料等。综述了不同钌废料的综合回收处理方法,分别介绍了氧化蒸馏法转化可溶性盐、熔融—还原—氧化法、熔融—氧化—蒸馏法、微波浸出—浊点萃取法、蒸馏—熔融—还原法、熔融—还原—氧化法、离子交换法、氧化挥发法、电解法、生物吸附法和物理吸附法等工艺,总结了现有钌废料回收技术的优缺点,并对未来钌废料回收工艺的发展方向进行了展望。

Slag design and optimization for iron capturing platinum group metals from alumina-based spent catalysts

Production of petrochemical catalysts accounts for one of the largest shares of platinum group metals(PGMs) consumption;thus,recycling of spent petrochemical catalysts holds great economic value.Conventionally,PGMs are recovered through hydrometallurgical processes which have a low recovery efficiency and produce a large amount of waste.In this regard,this paper proposed a method to use iron-capturing PGMs based on CaO-Al_(2)O_(3)-Na_(2)O slag.This method avoided the formation of Fe-Si alloy and achieved efficient enrichment of PGMs.The droplet force model showed that the recovery efficiency of PGMs could be improved if the slag had low density and low viscosity.Based on this result,FactSage software optimized the composition of slag.Furthermore,the effect of B_(2)O_(3) on the 1400 ℃ liquidus of CaO-Al_(2)O_(3)-Na_(2)O_(3)-B_(2)O_(3) phase diagram was revealed.Moreover,it was found that the recovery efficiency of PGMs exceeded 99% under the following optimized conditions:basicity of 1.0,20 wt%Na_(2)O,15 wt% B_(2)O_(3),15 wt% Fe,3 wt% C and a temperature range of 1400-1500℃.The thermodynamic model revealed the mechanism of iron capture.Different chemical bonds prevented the formation of bonds between the alloy and slag,resulting in the separation of the slag from the alloy.PGMs particles and iron microspheres had significant surface Gibbs free energy.Only when iron microspheres and PGMs particles collided and fused with each other to reduce their surface area could the Gibbs free energy of the system be reduced.

非金属掺杂提升铂族金属电催化剂性能

铂族金属(PGM)催化剂被认为是用于能量转换和存储设备(如燃料电池和水电解器)的最佳催化剂之一,但活性和稳定性不足极大地限制了其商业化应用.近年来,非金属原子(氢、硼、碳、氮、磷和硫等)掺杂策略引起了广泛关注,该方法可以对铂族金属的精细电子和配位结构进行调控,从而优化铂族金属的电催化活性和稳定性.非金属掺杂具有独特的优势:首先,非金属的原子半径较小,可以进入铂族金属的间隙位点,为调节铂族金属的电子结构提供了更多的可能性;其次,掺杂的非金属会诱导强电荷转移,并与主体金属产生s,p-d杂化,这与金属-金属合金中的d-d轨道耦合不同;第三,非金属掺杂的铂族金属基催化剂由于具有较强的非金属-金属键,从而表现出较好的耐久性.本文详细探讨了非金属掺杂铂族金属催化剂的合成和应用,并揭示了非金属掺杂的催化机理和构效关系.本文总结了非金属掺杂铂族金属基催化剂在电催化领域的一些代表性进展,讨论了影响催化剂活性和稳定性的关键因素,并介绍了非金属掺杂改善铂族金属基催化剂性能的基本原理.探讨了非金属掺杂铂族金属基催化剂的表征技术和理论方法,其中包括可直接观测到非金属原子的先进成像技术以及原位表征方法,辅助以密度泛函理论以及分子动力学模拟等理论计算方法,以进一步揭示催化剂性能增强机制.详细列举了非金属掺杂铂族电催化剂的合成方法,从气相沉积、高温热解、湿化学合成到电化学原位合成,提供了详尽的合成方案,并提出了针对贵金属活性中心的非金属修饰策略,旨在为未来材料设计提供启示.概述了非金属掺杂铂族金属基催化剂在电催化中的应用,重点揭示了非金属掺杂带来的结构-性能构效关系.在活性方面,非金属掺杂可以从配体效应、应力效应、微应变等方面影响铂族金属的d带重心,从而影响活性位点与反应中间体的吸附,而这种影响作用也因每种非金属的电负性、原子半径、掺杂方式等不同而不同,可通过调控掺杂种类/方式实现精细调控;同时,非贵金属的协同效应可以增强对OH的吸附,抑制活性位点的毒化.在稳定性方面,非金属可以通过与金属形成稳定的金属-非金属键抑制金属的溶解,或者减弱金属与氧的相互作用,防止其被氧化;同时,非金属的掺入可以提高金属的功函数,提高其溶解电位,从而提升催化剂稳定性.最后,本文提出了该类电催化材料面临的机遇和挑战,其中包括:(1)开发更加可控的非金属掺杂策略;(2)更加深入地研究非金属掺杂带来的构效关系;(3)探索新的非金属掺杂催化剂,并进一步拓展到其他催化领域;(4)发展抑制非金属组分溶解的通用策略;(5)重视催化剂在器件层面的性能评估.综上,本文不仅为非金属掺杂贵金属基催化剂进一步的研究提供启示,还为深入理解催化、纳米材料的合成提供参考.

失效汽车催化剂中铂族金属火法富集概述

铂族金属作为重要的战略资源,在军事、航天、半导体、汽车等行业中有着广泛的应用,对于我国的发展起着不可或缺的作用。本文综述了目前失效汽车催化剂中铂族金属的火法回收现状,总结了各种方法的工艺流程和目前主要应用方向,包括金属捕集法中使用不同捕集剂造成的机理差异。对主要工艺路线存在的优缺点进行分析评述并提出改进方向。当下应大力发展协同捕集新技术,在保证回收率的同时还要控制富集后的合金成分以便于精炼,达成不同捕集剂之间的优势互补,为实现未来更加高效、绿色的铂族金属二次资源回收。

失效汽车尾气催化剂中铂族金属回收的研究进展

失效汽车尾气催化剂是回收铂族金属(铂、钯、铑)的重要二次资源。本文介绍了失效汽车尾气催化剂中铂族金属的回收工艺流程,包括失效催化剂预处理、铂族金属富集、分离与精炼三部分;详细介绍了两种高效预处理技术、两种富集方法以及四种分离与精炼工艺,总结了各种方法的原理、工艺流程、优缺点及改进方向。回收企业应根据回收规模和环保政策采用合适的回收工艺,以实现不同回收工艺之间的优势互补,未来需重点研发回收率高且环境友好的清洁回收工艺。

磁铁矿金属化焙烧高温捕集催化剂浸出渣回收铂族金属研究

针对汽车催化剂氧化浸出渣,开展磁铁矿金属化焙烧高温捕集回收铂族金属研究。重点研究捕集剂、还原剂、助熔剂、反应温度、反应时间对铂族金属捕集率的影响。试验结果表明,捕集剂配比20%,还原剂配比12%、助熔剂配比25%、焙烧温度1400℃、恒温反应时间4 h条件下,铂族金属铂、钯、铑的捕集率分别可达97.19%、92.88%、97.08%。

Study on the Leaching of Pt, Pd and Rh from Spent Auto-catalysts in Various Acidities

Auto-catalysts were the largest consumers of platinum group metals and the most important secondary resources, recovery of PGMs from spent auto-catalysts by leaching with various acidities were investigated. The leaching thermodynamics of PGMs at 363 K was first discussed. At 363 K the higher the acidities of HCl, the higher the leaching recoveries of PGMs, and the sequence of leaching recovery was Pd>Pt>Rh. When H2SO4 used alone, the leaching recoveries of PGMs was low, when the acidity of H2SO4 increasing, the leaching recovery of Rh kept stable.

从废催化剂中回收铂族金属处理工艺及污染管控要求浅析

汽车尾气废催化剂是重要的铂族金属二次资源,从中回收铂族金属具有十分重要的意义。通过对失效汽车尾气催化剂的湿法富集处理工艺进行介绍,对湿法冶炼过程中产生的三废进行有效治理,提出污染物排放管控要求和环境风险防控要求及新形势下的环境管理要求,实现了废弃资源再利用过程中满足环保节能、绿色高效、有价元素协同回收的环境管理新要求。

汽车中报废尾气催化剂的性质及失效原因

由于缺乏对废尾气催化剂的全面表征,导致对其物理化学性质及失效原因的了解不完全,影响其中铂族金属的回收。为此,对报废尾气催化剂进行了化学组成和物相、表面元素、微观形貌、粒度、比表面积和热稳定性等一系列性质表征分析,得出其失效原因主要包括铂族金属硫化及磷化中毒、催化剂表面积碳吸附、铂族金属氧化、烧结团聚及铂族金属在载体内的包裹、比表面积和总孔体积缩小等。

Recovery of platinum from spent automotive catalyst based on hydrometallurgy

Platinum(Pt)is a critical raw material for automotive catalytic converters due to its high-temperature stability,corrosion resistance and catalytic activity,whereas its limited primary resources and uneven distribution make it hard to meet the growing demand of platinum.Spent automotive catalyst(SAC)is currently the most important secondary resource of platinum,of which the platinum content is much higher than that of the primary platinum resources.The recovery process of platinum from spent automobile catalyst mainly consists of pretreatment followed by enrichment and refining,involving pyro-and hydrometallurgical techniques,among which enrichment and refining processes are extremely important for platinum recovery from spent automobile catalyst.This paper provides an overview of the technologies for platinum recovery from spent automotive catalyst.The emphasis is placed on the processes of enrichment and refining based on hydrometallurgical techniques.Future directions of research and development of platinum recovery from spent automobile catalyst are also proposed.

火法铋捕集废汽车催化剂中Pt、Pd、Rh的机理

废汽车催化剂中铂族金属的绿色高效富集一直是制约二次资源综合利用的关键问题。本文对铋捕集铂族金属的熔炼渣型和还原热力学进行了模拟计算,实验考察了多种因素对铂族金属回收率的影响,重点对单铂族金属贵铋进行微观表征。结果表明:通过控制Na_(2)B_(4)O_(7)·10H_(2)O和Na_(2)CO_(3)用量,可形成Na_(2)O-B_(2)O_(3)-SiO_(2)-(15%)Al_(2)O_(3)四元渣系,得到具有低熔点的NaAl_(8)O_(14)和Na_(2)Al_(12)O_(18)渣相,在优化条件下Pt、Pd、Rh的回收率分别为96.63%、95.71%、95.70%,贵铋的XRD分析结果表明,Bi与单独的Pt、Pd、Rh可分别形成Bi_(2)Pt、Bi_(2)Pd、Bi_(2)Rh物相,XPS表征结果显示Bi为0和+3价,Bi-Pt贵铋中Pt^(2+)、Pt^(4+)的比例分别为76.89%、23.11%,Bi-Pd贵铋中Pd^(2+)、Pd^(3+)所占比例分别为79.19%、20.81%,Bi-Rh贵铋中Rh~0、Rh^(3+)所占比例分别为62.50%、37.50%。本研究结果可为火法熔炼金属捕集铂族金属的理论体系提供一定的有益补充。

废汽车三元催化剂湿法回收铂族金属研究

废汽车三元催化剂铂族金属含量较高,随着报废汽车爆发式增长,成为铂族金属开发的重要二次资源。湿法回收铂族金属,具有能耗低、规模灵活的特点,适宜地域内废汽车三元催化剂的消纳。开展预处理-氧化酸浸湿法富集铂族金属工艺研究,较为系统研究预处理方法、氧化酸浸试验条件对铂族金属浸出率影响。试验结果表明,湿法氧化酸浸能有效回收铂族金属,原料细度、盐酸浓度、浸出温度、浸出时间对浸出率影响较大,运用水合肼还原预处理可大幅提高铂族金属浸出率。

废三元催化剂资源回收问题剖析及对策研究

报废汽车尾气三元催化剂作为危险废物的同时也是提炼铂族金属重要的资源。介绍了我国废三元催化剂的回收管理政策与主流回收利用技术,分析了上海市废三元催化剂的基本特征与上海市废三元催化剂回收困难的原因,并针对现存问题在政策层面提出了对策建议。

失效汽车尾气催化剂中贵金属的火法富集简述

根据目前贵金属应用前景、市场行情,从失效汽车催化剂中回收贵金属具有迫切性及必要性。综合考虑经济成本、回收效率、环保、安全、工艺成熟度以及可靠性,目前从失效汽车催化剂中回收贵金属主要采用火法富集、湿法精制提纯的工艺路线来展开。本文主要分析了采用火法冶金从失效汽车尾气催化剂中回收贵金属工艺的优缺点,并展望了在铂族金属回收领域中经济环保、且有利于工业化的工艺技术。

碱性氢氧化电催化剂研究进展

氢是一种清洁、可再生的能源载体,有望在未来促进低碳能源经济的发展。氢氧燃料电池可将氢能转为电能,大大提高了氢能源的转化效率。在碱性条件下运行的阴离子交换膜燃料电池(AEMFCs),由于可以利用低成本的非铂电催化剂来驱动阴极氧还原反应(ORR)引起了广泛关注。然而,AEMFCs的阳极氢氧化反应(HOR)的反应动力学与酸性条件下相比低2~3个数量级,需要高活性、高稳定性的HOR催化剂来驱动,因此大量的碱性HOR催化剂被设计开发。综述了近年来碱性HOR电催化剂的研究进展,介绍了碱性HOR的反应机理、性能评价标准以及近期报道的新型HOR催化剂,重点关注了这些催化剂的设计思路、催化性能、反应机理等,并对未来碱性HOR催化剂设计的挑战和机遇进行了展望。

铂族金属均相催化剂的研究和应用

铂族金属均相催化剂是一类特殊结构的金属配合物,具有均相催化氢化反应、羰基加成反应、酰氢化反应、烯烃氧化反应、C-C合成反应等的作用,在现代化学和制药工业中得到重要的应用。涉及的催化机理主要包括氧化加成、分子内配体重排、配体迁移和插入、还原消除。论文介绍和讨论了铂族金属均相催化剂的历史、应用、催化机制和最新的进展。

加压碱浸处理-氰化浸出法回收汽车废催化剂中的贵金属

为提高铂族金属的浸出回收率,针对前期研究提出的汽车废催化剂先经加压碱浸处理而后再加压氰化浸出铂族金属的新工艺,变动预处理反应过程各种工艺参数,考察了对后续铂族金属氰化浸出指标的影响。结果表明:预处理可打开汽车废催化剂载体对铂族金属的包裹,有利于其氰化浸出;但物料粒度过细或反应碱用量过大、温度过高、时间过长均容易形成新相重新包裹,不利于氰化试剂与铂族金属有效接触;预处理渣进一步湿磨,可消除包裹,提高氰化浸出率;在实验最佳条件下,铂族金属氰化浸出率分别可达到:Pt 96%、Pd 98%、Rh92%。