resumo
Electrochemical reduction of iron oxides into zero-valent iron (ZVI, Fe-0) is a promising alternative to the traditional methods used for iron production. The electrochemical deposition of Fe-0 from hematite and hematite-based Fe2-xAlxO3 ceramic in alkaline suspensions (10 M of NaOH) was assessed at relatively low temperature (90 degrees C). Ceramic compositions aimed to mimic the main components of red mud waste from the alumina refining industry for iron valorisation purposes. The impact of aluminium content on the electroreduction and microstructure of the deposited Fe-0 films was demonstrated and discussed. Trapping and following the leaching of the aluminium species during deposition causes drastic morphological changes and induces significant porosity. Faradaic efficiencies of the reduction to Fe-0 were found to decrease from 70% to 32% for Fe2O3 and Fe1.4Al0.6O3, respectively. The results highlight possible effects imposed by aluminium presence during Fe-0 electrodeposition for future iron recycling from, for example, red mud or other aluminium containing wastes by electrowinning in alkaline conditions. (C) 2020 The Author(s). Published on behalf of The Electrochemical Society by IOP Publishing Limited.
palavras-chave
HEMATITE PARTICLES; METAL PRODUCTION; OXIDE; REDUCTION; ELECTROREDUCTION; NANOPARTICLES; CONDUCTIVITY; ELECTROLYSIS; SOLUBILITY; ELECTRODES
categoria
Electrochemistry; Materials Science
autores
Lopes, DV; Kovalevsky, AV; Quina, MJ; Frade, JR
nossos autores
Daniela Vanessa Rosendo Lopes
Investigador Júnioragradecimentos
The carried research was supported by the FCT grant PD/BD/114106/2015, the European Commission (project SIDERWINDLV-768788-Horizon 2020/SPIRE10) and the project CICECO-Aveiro Institute of Materials (ref. UIDB/50011/2020 and UIDP/50011/2020), financed by the COMPETE 2020 Program and National Funds through the FCT/MEC and when applicable cofinanced by FEDER under the PT2020 Partnership Agreement.