Successive methods for the separation of titanium oxide from the black sands of Ecuador

Abstract

The black sands found on certain Ecuadorian beaches present a high ilmenite contents up to 50%. In this work, TiO2 was obtained from the black sands of Muisne beaches - Ecuador by combining the thermal, chemical and ion exchange treatments. For the thermal treatment, the raw material was smelted at temperature of 1100°C using a basic flux. Subsequently, the chemical treatment was initiated in the presence of Fe0 metal using chemical digestion with HCl, and the sample was purified by separating the precipitates from a series of reactions developed at different pHs with NH4OH, Na2S and HCl. The final effluent resulting from the last HCl digestion was purified by ion exchange using Amberlite IRA 400 resin of strongly anionic character. The effluent is then treated in basic medium and the resulting precipitate is calcined. The recovery yield of the TiO2 pigment was 46% with 92% purity.