Article (Scientific journals)
Efficient Extraction of Ta and Nb from a Coltan Ore Through Alkaline Roasting, Water Leaching, Precipitation, and Oxalic Acid Leaching
Shikika, A.; Zabene, F.; Muvundja, F. A. et al.
2022In Journal of Sustainable Metallurgy
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Keywords :
Coltan, niobium, tantalum, roasting, hydrometallurgy
Abstract :
[en] Current industrial processes of tantalum (Ta) and niobium (Nb) extraction from primary resources rely in majority on hydrofluoric (HF) acid leaching, which is raising material handling and safety issues. In this work, a novel HF-free treatment route for a coltan ore, based on alkaline roasting, water-leaching, precipitation and oxalic leaching is presented. A raw ore from Lulingu deposit (the Democratic Republic of the Congo) was subjected to alkaline roasting followed by water leaching to bring Ta and Nb into solution. The most influential operating parameters of the roasting were outlined using Taguchi ortogonal array L16 (44) method. The optimal roasting conditions determined as temperature (450°C), roasting time (2 h), molar ratio KOH/(Ta,Nb)2O5 of 13.2 (mass ratio KOH to ore of about 2/1) and granulometric fraction (-105+75 µm), enabled about 87 % of Ta and 92% of Nb to be subsequently water leached. The resulting alkaline pregnant leach solution (PLS) was subjected to precipitation, followed by oxalic acid leaching of the formed precipitates. This step brought about 86% of Ta and 92% of Nb in solution confirming the efficiency of the method. Globally, a total recovery of 74.8% Ta and 84.6% of Nb could be reached in the whole process. In addition, the obtained Ta-Nb leachate was deemed suitable to downstream solvent extraction in view yielding high purity Ta2O5 and Nb2O5 compounds.
Disciplines :
Geological, petroleum & mining engineering
Chemical engineering
Author, co-author :
Shikika, A.
Zabene, F.
Muvundja, F. A.
Mugumaoderha, M. C.
Aatach, Mohamed  ;  Université de Liège - ULiège > Département ArGEnCo > Traitement et recyclage des matières minérales (y compris les sols)
Gaydardzhiev, Stoyan  ;  Université de Liège - ULiège > Département ArGEnCo > Traitement et recyclage des matières minérales (y compris les sols)
Language :
English
Title :
Efficient Extraction of Ta and Nb from a Coltan Ore Through Alkaline Roasting, Water Leaching, Precipitation, and Oxalic Acid Leaching
Publication date :
11 November 2022
Journal title :
Journal of Sustainable Metallurgy
ISSN :
2199-3823
eISSN :
2199-3831
Publisher :
Springer Science and Business Media LLC
Peer reviewed :
Peer Reviewed verified by ORBi
Available on ORBi :
since 12 November 2022

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