Аннотация:The effect of fluoride concentration and fluid pressure on the niobium oxide solubility at T = 550o C and P = 50, 100, 200 and 500MPa in NaF solutions with concentrations of 0.1 and 1.0 m was experimentally studied. It was found that with an increase in pressure from 50 to 200 MPa, the Nb content in 0.1 m NaF solutions decreases by 0.5 orders of magnitude, and in 1 m NaF solutions the Nb content increases by 0.5 orders of magnitude. With a further increase in pressure to 500 MPa, the niobium content practically does not change and remains in the range of 10-3 mol/kg H2O in 0.1 m NaF solutions and 10-2 mol/kg H2O in 1 m NaF solutions.
