Study on Solubility of Nb2O5 in KOH Solution and Alkali Leaching of Niobite
来源期刊：中南大学学报(英文版)2000年第4期
论文作者：ZHOU Kang-gen TOKUDA Masanori
文章页码：171 - 174
Key words：niobium; solubility; alkali leaching
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℃ to 200℃at various molar ratios of K2Oto 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℃, but decreases it above 120℃. The leaching behaviors of Nb and Ta were studied in the range of 150℃ to 250℃and 0.1 M Pa to 5 MPa. With the rise of temperature, the leaching degree increases when the leaching temperature is below 200℃, but it decreases when the leaching temperature is above 200℃. The maximum leaching degree is about 90% at 200℃. It was proved that the alkali hydrothermal leaching process is effective for the recovery of Nb and Ta from niobite concentrate.
