The Effect of Activator on the Oxidative Corrosion Electrochemistry of Clay Vanadium Ore

Abstract

The effect of activator MF on the corrosion electrochemistry of clay vanadium ore in sulfuric acid solution was studied by open circuit potential testing, Tafel polarization curves, and AC impedance spectroscopy, and the changes in apparent morphology and chemical bonding of clay vanadium ore before and after leaching were analyzed. In the activator-less leaching system, the corrosion potential and electron transfer impedance of clay vanadium ore are higher, but after adding MF, the corrosion potential and electron transfer impedance decreased. By adding the amount of MF activator, the corrosion current density also increases, and the oxidation dissolution rate of clay vanadium ore accelerates. When the mass ratio of manganese oxide to fluoride is 1:3, the clay vanadium ore has lower Tafel corrosion potential and electron transfer impedance. From an electrochemical perspective, this analysis explains why the leaching rate with MF activator is higher than without activator. In addition, the MF activator causes the surface of clay vanadium ore particles to become loose and porous, and the specific surface area of mineral particles become larger. At the same time, the activator can also destroy the chemical bonding of silicon oxygen tetrahedron and aluminum oxygen octahedron in vanadium-bearing minerals to a certain extent, so as to promote vanadium leaching.

Keywords: Vanadium extraction, electrochemistry, polarization curve, activated acid leaching, clay vanadium ore