Community Research and Development Information Service - CORDIS

New eco-friendly alternative for metal extraction

Thanks to the innovative work of EU-funded researchers, the beneficiation of columbite and tantalite minerals can take place with the addition of just a few chemicals.
New eco-friendly alternative for metal extraction
Often associated geologically, tantalum and niobium ─ formerly known as columbium ─ have very different end-uses. Tantalum is mainly used in the manufacture of electronic capacitors for mobile phones, laptops and other electronic equipment. By far the greatest part of world's niobium production ends up in high-strength, stainless steels.

Both tantalum and niobium do not occur naturally as free metals but are found in a wide range of minerals. The EU-funded project E4-CRITMAT (Engineering of energy efficient extraction of critical materials - Application to the processing of niobium and tantalum minerals) was launched to implement new technologies for their extraction from minerals.

The aim of the E4-CRITMAT project was to eliminate the use of hydrofluoric acid, a highly hazardous chemical. To achieve this, researchers demonstrated that roasting low-grade niobium-tantalum ores with alkali salts is an attractive alternative. The ores could be roasted and decomposed with potassium or sodium hydroxide or carbonate and then leached with ionic liquids.

The project team carried a series of experiments to determine the optimal conditions for roasting in oxidising conditions to upgrade the initial minerals. Niobium and tantalum of high purity could ultimately be recovered (with a concentration up to 90 %) through electron deposition and liquid membrane separation techniques.

Among the many benefits of the new approach to processing niobium and tantalum minerals is that rare earth oxides are not attacked by alkali salts during roasting. They are physically liberated from the mineral lattice. In addition to the high added value sub-products, the integrating of the individual processes reduces waste production.

With the depletion of high-grade ores and concerns about the degradation of the environment, the utilisation of lean grade resources has become more urgent. The E4-CRITMAT technology offers the possibility of niobium and tantalum extraction in a "cleaner" and environment-friendly fashion with optimal resource utilisation.

Related information


Metal extraction, beneficiation, tantalum, niobium, roasting, rare earth oxides
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