Development of a Hydrometallurgical Process to Obtain High-Purity Alumina Using Bauxite

AluminaAlumina is produced commercially by the Bayer processBayer process, leading to tailings generation. For this reason, it is necessary to develop methodologies to remove the compounds that are not interesting, thereby producing liquors rich in aluminumAluminum and resulting in high-purity aluminaAlumina. This study aims to obtain high-purity aluminaHigh purity alumina from lateritic bauxiteBauxite through hydrometallurgical processes by leachingLeaching bauxites with both sulphuric and hydrochloric acids at varying concentrations, temperatures, solid/liquid ratios, and process times. The resulting acid extraction liquors were treated using solvent extraction processes that involved two types of extractants (D2EHPA and Alamine 336), varying pHs, kerosene/extractant ratios, and temperatures. The purified liquors were precipitated with ammonium hydroxide at pH 3 then the precipitatesPrecipitates were calcined at 1200 °C and analyzed by ICP-OES to verify transformation into aluminaAlumina and assess purity. The results showed that sulfuric acid extracted 100% of the ironIron and aluminumAluminum in the samples. In solvent extraction, Alamine 336 (pH = 0) and D2EHPA (pH -0.5) obtained an extraction rate of more than 90% for iron and less than 15% for aluminumAluminum. Following purificationPurification, 99.99% purity was achieved with D2EHPA.