Hydrometallurgical recovery of platinum-group metals from spent auto-catalysts: Focus on leaching and solvent extraction
Autor(a) principal: | |
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Data de Publicação: | 2022 |
Outros Autores: | , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10400.9/3860 |
Resumo: | ABSTRACT: To ensure the supply of raw materials for products of extreme importance in strategic sectors, the recovery of critical metals from secondary sources becomes increasingly urgent. Platinum group metals (PGMs), being rare and very valuable, fall into this demand, and the catalytic converters that contain them are recognized as one of the main sources. Hydrometallurgical processes have been proposed as an alternative to pyrometallurgical ones, with leaching and separation by solvent extraction being core operations in this type of processing. This article investigates these two operations, seeking to optimize conditions and propose new arrangements to improve them. Two different catalyst samples were considered in the experimental work. Leaching was carried out involving concentrated HCl solutions (with H2O2 as oxidant) and low liquid/solid ratios, seeking to maximize PGMs recovery, guaranteeing their high concentration in leachates and minimizing aluminum co-dissolution. Cerium leaching was also followed since this is a rare-earth metal with potential interest. Temperature, HCl concentration, liquid/solid ratio (L/S), time and particle size factors were evaluated, and the optimized conditions found were 11.6 mol L-1 HCl, 1%vol H2O2, 60 C, L/S = 2 L kg(-1) and 3 h, leading to PGM yields of 90-98% Pt, 99% Pd and 70-96% Rh, and leachate compositions of 0.41-0.78 g L-1 Pt, 1.6 g L-1 Pd, 0.062-0.066 g L-1 Rh, depending on the catalyst sample.& nbsp;For solvent extraction (SX), several commercial extractants dissolved/diluted in toluene were checked, firstly with a model solution, and then applied to the real spent auto-catalyst (SAC) leachates produced in-situ. The overall results showed that the most promising SX systems among those tested were Cyanex (R) 471X and Cyphos (R) IL 101. Cyanex (R) 471X allowed the quantitative extraction of Pd(II) and Fe(III), but the latter was conveniently scrubbed by water prior to Pd(II) stripping by an acidic thiourea solution. Pt(IV) and Pd(II) extraction values by Cyphos (R) IL 101 were very encouraging, as only Fe(III) and Zn(II) were appreciably co-extracted, however, scrubbing of the contaminating metals, and Pd(II) and Pt(IV) stripping, did not work. Hence, investigation to find proper scrubbing/stripping agents for Cyphos (R) IL 101 SX system, to recover PGMs from recycled SACs, is further needed. |
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Hydrometallurgical recovery of platinum-group metals from spent auto-catalysts: Focus on leaching and solvent extractionHydrometallurgyRecyclingLeachingPlatinum-group metalsSolvent extractionABSTRACT: To ensure the supply of raw materials for products of extreme importance in strategic sectors, the recovery of critical metals from secondary sources becomes increasingly urgent. Platinum group metals (PGMs), being rare and very valuable, fall into this demand, and the catalytic converters that contain them are recognized as one of the main sources. Hydrometallurgical processes have been proposed as an alternative to pyrometallurgical ones, with leaching and separation by solvent extraction being core operations in this type of processing. This article investigates these two operations, seeking to optimize conditions and propose new arrangements to improve them. Two different catalyst samples were considered in the experimental work. Leaching was carried out involving concentrated HCl solutions (with H2O2 as oxidant) and low liquid/solid ratios, seeking to maximize PGMs recovery, guaranteeing their high concentration in leachates and minimizing aluminum co-dissolution. Cerium leaching was also followed since this is a rare-earth metal with potential interest. Temperature, HCl concentration, liquid/solid ratio (L/S), time and particle size factors were evaluated, and the optimized conditions found were 11.6 mol L-1 HCl, 1%vol H2O2, 60 C, L/S = 2 L kg(-1) and 3 h, leading to PGM yields of 90-98% Pt, 99% Pd and 70-96% Rh, and leachate compositions of 0.41-0.78 g L-1 Pt, 1.6 g L-1 Pd, 0.062-0.066 g L-1 Rh, depending on the catalyst sample.& nbsp;For solvent extraction (SX), several commercial extractants dissolved/diluted in toluene were checked, firstly with a model solution, and then applied to the real spent auto-catalyst (SAC) leachates produced in-situ. The overall results showed that the most promising SX systems among those tested were Cyanex (R) 471X and Cyphos (R) IL 101. Cyanex (R) 471X allowed the quantitative extraction of Pd(II) and Fe(III), but the latter was conveniently scrubbed by water prior to Pd(II) stripping by an acidic thiourea solution. Pt(IV) and Pd(II) extraction values by Cyphos (R) IL 101 were very encouraging, as only Fe(III) and Zn(II) were appreciably co-extracted, however, scrubbing of the contaminating metals, and Pd(II) and Pt(IV) stripping, did not work. Hence, investigation to find proper scrubbing/stripping agents for Cyphos (R) IL 101 SX system, to recover PGMs from recycled SACs, is further needed.ElsevierRepositório do LNEGPaiva, A. P.Piedras, Francisco VegaRodrigues, Pedro G.Nogueira, Carlos2022-05-19T10:08:18Z2022-04-01T00:00:00Z2022-04-01T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleapplication/pdfhttp://hdl.handle.net/10400.9/3860engPaiva, A.P... [et.al.] - Hydrometallurgical recovery of platinum-group metals from spent auto-catalysts: Focus on leaching and solvent extraction. In: Separation and Purification Technology, 2022, Vol. 286, article nº 1204741383-586610.1016/j.seppur.2022.1204741873-3794info:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2022-09-06T12:29:42Zoai:repositorio.lneg.pt:10400.9/3860Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-19T15:37:06.985867Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse |
dc.title.none.fl_str_mv |
Hydrometallurgical recovery of platinum-group metals from spent auto-catalysts: Focus on leaching and solvent extraction |
title |
Hydrometallurgical recovery of platinum-group metals from spent auto-catalysts: Focus on leaching and solvent extraction |
spellingShingle |
Hydrometallurgical recovery of platinum-group metals from spent auto-catalysts: Focus on leaching and solvent extraction Paiva, A. P. Hydrometallurgy Recycling Leaching Platinum-group metals Solvent extraction |
title_short |
Hydrometallurgical recovery of platinum-group metals from spent auto-catalysts: Focus on leaching and solvent extraction |
title_full |
Hydrometallurgical recovery of platinum-group metals from spent auto-catalysts: Focus on leaching and solvent extraction |
title_fullStr |
Hydrometallurgical recovery of platinum-group metals from spent auto-catalysts: Focus on leaching and solvent extraction |
title_full_unstemmed |
Hydrometallurgical recovery of platinum-group metals from spent auto-catalysts: Focus on leaching and solvent extraction |
title_sort |
Hydrometallurgical recovery of platinum-group metals from spent auto-catalysts: Focus on leaching and solvent extraction |
author |
Paiva, A. P. |
author_facet |
Paiva, A. P. Piedras, Francisco Vega Rodrigues, Pedro G. Nogueira, Carlos |
author_role |
author |
author2 |
Piedras, Francisco Vega Rodrigues, Pedro G. Nogueira, Carlos |
author2_role |
author author author |
dc.contributor.none.fl_str_mv |
Repositório do LNEG |
dc.contributor.author.fl_str_mv |
Paiva, A. P. Piedras, Francisco Vega Rodrigues, Pedro G. Nogueira, Carlos |
dc.subject.por.fl_str_mv |
Hydrometallurgy Recycling Leaching Platinum-group metals Solvent extraction |
topic |
Hydrometallurgy Recycling Leaching Platinum-group metals Solvent extraction |
description |
ABSTRACT: To ensure the supply of raw materials for products of extreme importance in strategic sectors, the recovery of critical metals from secondary sources becomes increasingly urgent. Platinum group metals (PGMs), being rare and very valuable, fall into this demand, and the catalytic converters that contain them are recognized as one of the main sources. Hydrometallurgical processes have been proposed as an alternative to pyrometallurgical ones, with leaching and separation by solvent extraction being core operations in this type of processing. This article investigates these two operations, seeking to optimize conditions and propose new arrangements to improve them. Two different catalyst samples were considered in the experimental work. Leaching was carried out involving concentrated HCl solutions (with H2O2 as oxidant) and low liquid/solid ratios, seeking to maximize PGMs recovery, guaranteeing their high concentration in leachates and minimizing aluminum co-dissolution. Cerium leaching was also followed since this is a rare-earth metal with potential interest. Temperature, HCl concentration, liquid/solid ratio (L/S), time and particle size factors were evaluated, and the optimized conditions found were 11.6 mol L-1 HCl, 1%vol H2O2, 60 C, L/S = 2 L kg(-1) and 3 h, leading to PGM yields of 90-98% Pt, 99% Pd and 70-96% Rh, and leachate compositions of 0.41-0.78 g L-1 Pt, 1.6 g L-1 Pd, 0.062-0.066 g L-1 Rh, depending on the catalyst sample.& nbsp;For solvent extraction (SX), several commercial extractants dissolved/diluted in toluene were checked, firstly with a model solution, and then applied to the real spent auto-catalyst (SAC) leachates produced in-situ. The overall results showed that the most promising SX systems among those tested were Cyanex (R) 471X and Cyphos (R) IL 101. Cyanex (R) 471X allowed the quantitative extraction of Pd(II) and Fe(III), but the latter was conveniently scrubbed by water prior to Pd(II) stripping by an acidic thiourea solution. Pt(IV) and Pd(II) extraction values by Cyphos (R) IL 101 were very encouraging, as only Fe(III) and Zn(II) were appreciably co-extracted, however, scrubbing of the contaminating metals, and Pd(II) and Pt(IV) stripping, did not work. Hence, investigation to find proper scrubbing/stripping agents for Cyphos (R) IL 101 SX system, to recover PGMs from recycled SACs, is further needed. |
publishDate |
2022 |
dc.date.none.fl_str_mv |
2022-05-19T10:08:18Z 2022-04-01T00:00:00Z 2022-04-01T00:00:00Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10400.9/3860 |
url |
http://hdl.handle.net/10400.9/3860 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
Paiva, A.P... [et.al.] - Hydrometallurgical recovery of platinum-group metals from spent auto-catalysts: Focus on leaching and solvent extraction. In: Separation and Purification Technology, 2022, Vol. 286, article nº 120474 1383-5866 10.1016/j.seppur.2022.120474 1873-3794 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.publisher.none.fl_str_mv |
Elsevier |
publisher.none.fl_str_mv |
Elsevier |
dc.source.none.fl_str_mv |
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Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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