Experimental study of natural pyrochlore and niobium oxide solubility in Alkaline hydrothermal solutions

摘要

The concentration and temperature dependences of pyrochlore and Nb oxide solubility in Na2CO3 and Na2DO-3 + NaF aqueous solutions with concentrations from 0.01 to 2.0 m at 300-550A degrees C and 50 and 100 MPa (the Co-CoO buffer) are studied. It is established that the Nb equilibrium content in the solution increases at 550A degrees C and 100 MPa with an increase in mNa(2)CO(3) and reaches the value of 10(-4) m. The Nb2O5 solubility almost does not change as the concentration of Na2CO3 increases and is found within 10(-6) to 10(-5.5) m.