Electrochemical purification of kaolinitic for removing Fe and Ti oxides applying an ultrasonic pre-treatment

• Published in: Applied clay science 2018-09, Vol.162, p.461-468
• Main Authors: Melo-López, A.A., Veloz-Rodríguez, M.A., Reyes-Cruz, V.E., Urbano-Reyes, G., Cobos-Murcia, J.A., Legorreta-García, F.
• Format: Article
• Language: English
• Subjects: Electrochemical purification; Fe and Ti oxides; Kaolinitic clay purification; Ultrasonic pre-treatment
• ISSN: 0169-1317; 1872-9053
• DOI: 10.1016/j.clay.2018.06.041

A study to determine the mechanisms of electrochemical purification and the effect of ultrasonic pre-treatment to remove impurities of Fe and Ti oxides was presented with the intention of optimizing the purification process of kaolinitic clays and increasing their use in different industrial applications. Cyclic voltammetry and chronoamperometry studies as well as SEM/EDS, ICP and whiteness index (WI) were conducted to evaluate the electrochemical purification of four different kaolinitic clays (ACE, CFL, ASC and AAM), with and without ultrasonic pre-treatment. The results show that the purification of kaolinitic clays was initially carried out by the chemical dissolution of Fe and Ti oxides, with oxalic acid added and pH 90, when ultrasonic pre-treatment was applied, thus increasing their use in different applications. •Thermodynamic conditions were determined for dissolution of Fe and Ti oxides.•Effect of ultrasonic pre-treatment on the purification of clays was determined.•The mechanisms for the electrochemical purification of clays are proposed.•Whiteness degree in the clays after of electrochemical purification was determined.