abstract
Alkaline electrowinning is a promising sustainable ironmaking technology, characterised by operation at low temperatures and reduced energy consumption, in contrast to the traditional route which produces CO2 emissions. While hematite has been the primary focus of most studies, only a limited number of alternative iron-based raw materials have been investigated as potential feedstocks for electrowinning. This work aims to evaluate, for the first time, the valorisation potential of a beta-FeOOH based residue, using pretreatment-free electrowinning. The electroreduction experiments conducted in 10 M NaOH at 90 degrees C (0.025 A.cm-2) achieved a Faradaic efficiency of 59 %, comparable to pure hematite (57 %), which is traditionally regarded as a primary iron source in electrowinning for green steelmaking. Increasing the electrolyte concentration to 18 M at 105-130 degrees C, decreased the efficiency by about 20 % in comparison to hematite, revealing a lower quality of iron deposits. However, potentiostatic electrowinning in the reference conditions, -1.15 V in 10 M NaOH, successfully reached an unprecedented 83 % Faradaic efficiency, accompanied by an improvement in the quality of the iron deposits. These results highlight a high potential of beta-FeOOH-containing industrial residues for direct valorisation through electrowinning, contributing to a more sustainable steelmaking process.
keywords
ALKALINE-SOLUTION; HEMATITE; SOLUBILITY; REDUCTION; PARTICLES; METAL; NAOH
subject category
Electrochemistry
authors
Duarte, F; Lisenkov, AD; Kovalevsky, A; Lopes, D
our authors
Aleksey Lisenkov
Junior Researcher
Andrei Kavaleuski
Principal Researcher
Daniela Vanessa Rosendo Lopes
Junior ResearcherProjects
CICECO - Aveiro Institute of Materials (UIDB/50011/2020)
CICECO - Aveiro Institute of Materials (UIDP/50011/2020)
Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)
acknowledgements
The authors acknowledge SIDERWIN European project (SIDERWIN-DLV-768788-Horizon 2020/SPIRE10) , and CICECO-Aveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020 & LA/P/0006/2020, financed by national funds through the FCT/MCTES (PIDDAC) . Daniela V. Lopes acknowledges the support of her Research Employment Contract FCT (2023.07163.CEECIND) .