Preparation of La2O3 by ion-exchange membrane electrolysis of LaCl3 aqueous solution

Abstract

The ion-exchange membrane electrolysis technology was applied inventively in the preparation of lanthanum hydroxide, after calcination, lanthanum oxide was obtained eventually. The effect of the concentration of lanthanum chloride solution on electrolytic product was mainly investigated. The phase composition, micro morphology, particle size and chlorine content of the product were characterized, respectively. Under the conditions of this work, the product that forms by electrolysis of LaCl3 aqueous solution directly is La(OH)3. When the initial concentration of LaCl3 changes from 0.1 to 0.5 mol/L, the current efficiency of La(OH)3 increases from 60% to 85%, the product roasted at 800 °C for 1.5 h is La2O3, whose median particle size (D50) is 10–20 μm, the mass fraction of chloride ion is less than 0.02 wt%. Additionally, the prepared La2O3 particles are porous and non-spherical particles, which are composed of small crystals with sheet structure.