Characterization of Minim-Martap Bauxite and Its Extracted Alumina

Abstract

Due to their chemical and mineralogical properties bauxites are composites with multiple applications. In this work, the properties of bauxite collected from Minim-Martap and its extracted alumina were evaluated. Alumina was extracted by adapting the Bayer process at laboratory scale while the characteristics of bauxite and alumina were variably characterized by determining the particle size distribution, relative humidity, loss on ignition, pH, EC, CEC, PZC, XRD, IR, and DSC-TGA. These results show that Minim-Martap bauxite gray bauxite with easily extractable alumina. This bauxite is acidic with a pH of 6.05, PZC of 6.91 and CEC of 15 Meq/100 g which is closer to that of kaolinite clays. This result was confirm by XRD which shows two types of kaolinites: Al2Si2O5(OH)4 with 83.24% and H4Al2Si2O9 with 42.47%, mullite Al2.25Si0.75O4.875 with 67.32%, gibbsite (H2SiO4) with 83.92%. The bauxite is hydroscopic as evident from its humidity results. The IR spectroscopy of bauxite and alumina shows the presence of Al-OH and Si-OH which increase with acid treatment. Minim-martap bauxite and its extracted alumina can be used as raw materials for many industrial processes because of the different properties they possess as revealed by this study.