Recovery of TiO2 from Titaniferous Sand of Esmeraldas- Ecuador, using Ion Exchange Resins

Abstract

The titanium oxide (TiO₂) was recovered from ilmenite (FeO.TiO₂) contained in the titaniferous sands of Esmeraldas Province through ion exchange resins in combination with methods of magnetic concentration, thermal treatment and chemical treatment. The magnetic separation allowed to reach ilmenite concentrations  up to 57%.  Thermal treatment was by smelting using NaOH as flux in 2: 1 ratio at 1100°C. The chemical treatment was by acid digestion with HCl in the presence and absence of metallic iron with subsequent separations of the formed precipitates at different pH ,using NH₄OH, Na₂S, concentrated HCl, etc. Finally, the effluent of the last acidic digestion with concentrated HCl is subjected to ion exchange resin using strongly anionic Amberlite IRA 400  applying optimum flow and column design conditions. After the ion exchange, the effluent is subjected to precipitation and calcinations, obtaining titanium oxide pigment with 97% purity and 19% recovery in the absence of metallic iron, and 90% purity with 40% recovery in the presence of metallic iron.

Keywords: Titaniferous sands, titanium dioxide, resin of ionic exchange, ilmenite, acid digestion, Magnetic concentration.