Characterization and electrochemical treatment of a kaolin

Abstract

In this work, studies on characterization and electrochemical treatment of kaolin from the municipality of Agua Blanca, Hidalgo, Mexico were carried out, in order to identify its properties and establish the operating conditions for an electrochemical purification treatment. Different characterization techniques were used in order to quantify this clay characteristics, such as X-ray diffraction, scanning electron microscopy, analysis of the whiteness index, particle size, FTIR, Induced Coupled Plasma Spectroscopy, Z potential, cyclic voltammetry, chronopotentiometry and chronoamperometry. This study shows that the tested clay had a high content of kaolinite, but also impurities, such as: quartz, iron oxides, and titanium oxides. These impurities have an influence on the surface charge of the kaolin particles and therefore on their properties. The clay with a heat treatment exhibited a thermal behavior characteristic of this type of clays. The particle size range was between 0.5 and 100μm with an average particle size about 15μm. The voltammetry study revealed that a reduction processes occur in a range of 0.07 to −1.2V (E vs. SCE) and, when a cell potential of 3.3V for 24h was imposed, there was a decrease of about 43% in the amount of iron oxides present in the ore. This reduction was of particular significance for the cleaning process.