This work deals with the degradation of the azo-dye Orange II (OII) by a heterogeneous process with dark Fenton. Natural and purified ilmenites from Colombian soil were used as catalysts. The catalysts have different physicochemical properties and are basically composed of TiO2 and Fe2O3. Ilmenites (FeTiO3), raw materials highly available at low cost, were studied by means of conventional metallography (polished grain mounts), as well as BET, XRD, and XRF in order to determine their possible source area and the factors that influence their use as a catalyst for OII degradation. The pH, the ilmenite amount, the initial CH2O2, and the temperature of the reaction system were studied. Complete degradation of dye was observed within 7 h, while 90 % of OII was removed in 7 h using Cumaribo Ilmenite.