Solvent extraction of niobium from alkali solution by methyltrioctylammonium chloride

Abstract

For the purpose of developing an alkali leaching-solvent extraction directly from alkali solution process, the extraction of niobium from alkali solution by long-chain alkyl quternary ammonium salt (methyltrioctylammonium chloride R₄NCl) in toluene was investigated. The experiments were carried out under conditions of 25 °C, Nb(V) concentration 0.01 mol/L, pH 10.7–13.8, R₄NCI concentration 0.02–0.14 mol/L. It has been found that the distribution ratio of niobium increases with increasing R₄NCl concentration and with decreasing KCl concentration, but it shows maximum value at pH value of about 12 and decreases below or above this pH value. Distribution ratio of niobium goes up to over 1 000 in appropriate conditions, and so it has been proved that R₄NCl is an effective extractant for extraction of niobium from alkali solution.

Keywords

niobium / solvent extraction / distribution ratio / methyltrioctylammonium chloride

References

[1] ZhongHai-yun, ZhaoQin-shengA hand book for extractive metallurgy of nonferrous metals, rare refractory metals (II), 1999, Beijing, Metallurgical Industry Press(in Chinese)

[2] ZhouKang-gen, TokudaMasanori. Study on solubility of Nb₂O₅ in KOH solution and alkali leaching of niobite[J]. J Cental South University of Technology, 2000, 7(4): 171-174

[3] MillerG LTantalum and niobium[M], 1959, London, Butterworths Scientific Publications

[4] Cardon P B. Process for recovering niobium and tantalum from ores and ore concentrates containing same[P]. US Patent, No. 3058825. 1962.

[5] SpinnerB. Etude quantitative de I’hydrolyse des niobates de pottassium[J]. Revue de Chimie Minerale, 1968, 5: 839-868

[6] JanderG, ErtelD. Uber niobsauren und wasserlosliche alkaliniobate-III[J]. J Inorg Nucl Chem, 1960, 14: 85-90

[7] JehngJ M, WachsI E. Niobium oxide solution chemistry[J]. J Raman Spectroscope, 1991, 22(2): 83-89