Eliminating fluoride-induced corrosion of aluminum cathodes in zinc electrowinning by aluminum ion complexation

This paper discusses the effect of fluoride on the corrosion behavior of aluminum alloy used as a mother blank in zinc electrowinning, focusing on the mitigation of the corrosive process by aluminum ion addition and fluoride complexation. Standardized corrosion immersion tests have shown that increa...

Full description

Saved in:
Bibliographic Details
Main Authors: N.G.S. Almeida, B.M. Ward, J.R. De Wet, A.D. Souza, V.S.T. Ciminelli, D. Majuste
Format: Article
Language:English
Published: Elsevier 2025-01-01
Series:Journal of Materials Research and Technology
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S223878542402982X
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1832595327425708032
author N.G.S. Almeida
B.M. Ward
J.R. De Wet
A.D. Souza
V.S.T. Ciminelli
D. Majuste
author_facet N.G.S. Almeida
B.M. Ward
J.R. De Wet
A.D. Souza
V.S.T. Ciminelli
D. Majuste
author_sort N.G.S. Almeida
collection DOAJ
description This paper discusses the effect of fluoride on the corrosion behavior of aluminum alloy used as a mother blank in zinc electrowinning, focusing on the mitigation of the corrosive process by aluminum ion addition and fluoride complexation. Standardized corrosion immersion tests have shown that increasing fluoride ion concentrations result in an increase in the corrosion rate of the aluminum alloy, but the addition of aluminum ions to the zinc sulfate electrolyte counteracts this effect by forming stable AlF2+ species. This favorable complexation reaction, thermodynamically modeled in this work, plays a critical role in reducing the activity of the corrosive HF species on the passive oxide layer of the aluminum surface. Electrochemical impedance spectroscopy and linear sweep voltammetry measurements supported these results. The presence of aluminum ions in the electrolyte, in amounts dependent on fluoride and sulfate concentrations, increases the charge transfer resistance at the interface and decreases the corrosion current. The work also proposes a method for the estimation of the amount of aluminum that is required to be added to the electrolyte in order to eliminate the fluoride-induced corrosion. The results of this research may help extend the life of the aluminum cathodes and thus reduce operating costs.
format Article
id doaj-art-60b6b74e31274e8597dd951f217c5c9b
institution Kabale University
issn 2238-7854
language English
publishDate 2025-01-01
publisher Elsevier
record_format Article
series Journal of Materials Research and Technology
spelling doaj-art-60b6b74e31274e8597dd951f217c5c9b2025-01-19T06:25:44ZengElsevierJournal of Materials Research and Technology2238-78542025-01-013421162126Eliminating fluoride-induced corrosion of aluminum cathodes in zinc electrowinning by aluminum ion complexationN.G.S. Almeida0B.M. Ward1J.R. De Wet2A.D. Souza3V.S.T. Ciminelli4D. Majuste5Department of Metallurgical and Materials Engineering, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, 31270-901, Brazil; Instituto Acqua, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, 31270-901, BrazilBefesa Zinc Metal, Mooresboro, North Carolina, 28114, United States of AmericaBefesa Zinc Metal, Mooresboro, North Carolina, 28114, United States of AmericaBefesa Zinc Metal, Mooresboro, North Carolina, 28114, United States of AmericaDepartment of Metallurgical and Materials Engineering, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, 31270-901, Brazil; Instituto Acqua, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, 31270-901, BrazilDepartment of Metallurgical and Materials Engineering, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, 31270-901, Brazil; Instituto Acqua, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, 31270-901, Brazil; Corresponding author. Department of Metallurgical and Materials Engineering, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, 31270-901, Brazil.This paper discusses the effect of fluoride on the corrosion behavior of aluminum alloy used as a mother blank in zinc electrowinning, focusing on the mitigation of the corrosive process by aluminum ion addition and fluoride complexation. Standardized corrosion immersion tests have shown that increasing fluoride ion concentrations result in an increase in the corrosion rate of the aluminum alloy, but the addition of aluminum ions to the zinc sulfate electrolyte counteracts this effect by forming stable AlF2+ species. This favorable complexation reaction, thermodynamically modeled in this work, plays a critical role in reducing the activity of the corrosive HF species on the passive oxide layer of the aluminum surface. Electrochemical impedance spectroscopy and linear sweep voltammetry measurements supported these results. The presence of aluminum ions in the electrolyte, in amounts dependent on fluoride and sulfate concentrations, increases the charge transfer resistance at the interface and decreases the corrosion current. The work also proposes a method for the estimation of the amount of aluminum that is required to be added to the electrolyte in order to eliminate the fluoride-induced corrosion. The results of this research may help extend the life of the aluminum cathodes and thus reduce operating costs.http://www.sciencedirect.com/science/article/pii/S223878542402982XAluminumAcid corrosionCorrosion inhibitionFluorideComplexation
spellingShingle N.G.S. Almeida
B.M. Ward
J.R. De Wet
A.D. Souza
V.S.T. Ciminelli
D. Majuste
Eliminating fluoride-induced corrosion of aluminum cathodes in zinc electrowinning by aluminum ion complexation
Journal of Materials Research and Technology
Aluminum
Acid corrosion
Corrosion inhibition
Fluoride
Complexation
title Eliminating fluoride-induced corrosion of aluminum cathodes in zinc electrowinning by aluminum ion complexation
title_full Eliminating fluoride-induced corrosion of aluminum cathodes in zinc electrowinning by aluminum ion complexation
title_fullStr Eliminating fluoride-induced corrosion of aluminum cathodes in zinc electrowinning by aluminum ion complexation
title_full_unstemmed Eliminating fluoride-induced corrosion of aluminum cathodes in zinc electrowinning by aluminum ion complexation
title_short Eliminating fluoride-induced corrosion of aluminum cathodes in zinc electrowinning by aluminum ion complexation
title_sort eliminating fluoride induced corrosion of aluminum cathodes in zinc electrowinning by aluminum ion complexation
topic Aluminum
Acid corrosion
Corrosion inhibition
Fluoride
Complexation
url http://www.sciencedirect.com/science/article/pii/S223878542402982X
work_keys_str_mv AT ngsalmeida eliminatingfluorideinducedcorrosionofaluminumcathodesinzincelectrowinningbyaluminumioncomplexation
AT bmward eliminatingfluorideinducedcorrosionofaluminumcathodesinzincelectrowinningbyaluminumioncomplexation
AT jrdewet eliminatingfluorideinducedcorrosionofaluminumcathodesinzincelectrowinningbyaluminumioncomplexation
AT adsouza eliminatingfluorideinducedcorrosionofaluminumcathodesinzincelectrowinningbyaluminumioncomplexation
AT vstciminelli eliminatingfluorideinducedcorrosionofaluminumcathodesinzincelectrowinningbyaluminumioncomplexation
AT dmajuste eliminatingfluorideinducedcorrosionofaluminumcathodesinzincelectrowinningbyaluminumioncomplexation