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Study on solubility of Nb2O5 in KOH solution and alkali leaching of niobite

  • Metallurgical Separation Science And Engineering
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Abstract

Solubility of Nb2O5 and leaching behaviors of Nb and Ta from niobite in KOH solution have been investigated in order to develop an alkali hydrothermal leaching process of Nb and Ta. The solubility of Nb2O5 was measured in the range of 40 °C to 200 °C at various molar ratios of K2O to Nb2O5(n(K2O)/n(Nb2O5)). It has been found that Nb2O5 shows the maximum solubility at the solution composition of n(K2O)/n(Nb2O5)=4/3 at a given temperature; the rise of temperature increases the solubility of Nb2O5 below 120 °C, but decreases it above 120 °C. The leaching behaviors of Nb and Ta were studied in the range of 150 °C to 250 °C and 0.1 MPa to 5 MPa. With the rise of temperature, the leaching degree increases when the leaching temperature is below 200 °C, but it decreases when the leaching temperature is above 200 °C. The maximum leaching degree is about 90% at 200 °C. It was proved that the alkali hydrothermal leaching process is effective for the recovery of Nb and Ta from niobite concentrate.

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Authors and Affiliations

  1. Metallurgical Separation Science and Engineering Lab., Central South University, 410083, Changsha, China

    Zhou Kang-gen

  2. Tohoku University, 980-77, Sendai, Japan

    Tokuda Masanori

Authors
  1. Zhou Kang-gen
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  2. Tokuda Masanori
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Additional information

Foundation item: The Key Project of Science and Technology Agency of Japan, 1994

Biography of the first author: ZHOU Kang-gen, doctor of engineering, professor, born in 1963, majoring in extractive metallurgy of rare metals and application of membrane separation technology.

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Zhou, Kg., Tokuda, M. Study on solubility of Nb2O5 in KOH solution and alkali leaching of niobite. J Cent. South Univ. Technol. 7, 171–174 (2000). https://doi.org/10.1007/s11771-000-0046-4

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  • DOI: https://doi.org/10.1007/s11771-000-0046-4

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