Effect of acid and electrochemical treatment on physicochemical and electrical properties of tantalite, columbite, zircon and feldspar

The article gives a report on integrated experimental research into targeted change of chemical and phase composition of surface and increase in contrast of physicochemical, electrical and electrochemical properties of tantalite, columbite and zircon under treatment by acid product of water electrolysis—anolyte (pH < 5) and by muriatic solution (HCl, pH 3–3.5). The X-ray photoelectron spectroscopy, high resolution spectroscopy and chemical and electrophysical techniques reveal the mechanism of structural–chemical surface transformation of tantalite, columbite, zircon and feldspar under leaching in acid solutions; this surface transformation mechanism consists in activation of dissolving of iron- and silicate-containing surface films and high-rate oxidation of iron atoms in surface layer of tantalite and columbite, with transition of Fe(II) to Fe(III) and surface destruction of zircon, with formation of oxygenvacant defects of SiO32− and SiO20 type under influence of anolyte.