Aluminum hydroxides in the soils of Chiapas

Abstract

The research aimed to locate areas with soils containing aluminum hydroxides soluble in alkalis, suitable for exploitation to obtain alumina. Based on edaphic-geological criteria, the study was conducted in the state of Chiapas. The work was carried out in two stages: in the first stage, sampling was conducted across the state as indicated by the guiding map (Figure 1); in the second stage, work focused on the Oxchuc area, which was found to be the most favorable based on data obtained in the first stage. This area contains undifferentiated Cretaceous limestones, bounded to the south by a fault, and in contact with Paleocene and Eocene deposits. The soils are lateritic. The exploration of Oxchuc was done intensively in one area and extensively in different directions, seeking trends where the soluble alumina content might increase. The alumina quantification in the laboratory was performed on the alkaline extract obtained through digestion under atmospheric pressure and boiling at that pressure. The sample analysis indicates the presence of aluminum hydroxides, and X-ray diffraction reveals that they are gibbsite. It is concluded that materials containing soluble alumina in alkalis, suitable for exploitation, exist, and further studies of the area are recommended.