Extraction and Characterization of Alumina from Ilella Kaolin

Abstract

The global increase in the demand of aluminium raises the interest for the production from other alternative sources than Bauxite. Also, due to limited availability of bauxite ores in Nigeria, the use of kaolin as an alternative resource for alumina production, has become very vital. Therefore, the need for a more sustainable and optimised process is necessary to address these challenges. Hence, this research successfully developed a sustainable and efficient method for extracting high-purity alumina (Al₂O₃) from kaolin using an optimised acid leaching technique. The study began with the collection and preparation of kaolin sourced from Ilella in Sokoto State, Nigeria. The kaolin underwent calcination at 750°C to produce metakaolin. At 90°C, meta-kaolin was leached using 5M HCl acid, followed by filtration. The filtrate was then combined with 5M NaOH at 90°C to form sodium aluminate, a process that also removed magnesium and iron hydroxides. The pH of the solution was adjusted by adding HCl. The resulting aluminium hydroxide was calcined at 800°C and 900°C for two hours each, converting it into alumina. After calcination, the material was cooled to room temperature inside the furnace. The final alumina product was characterised using X-ray Fluorescence (XRF) and Scanning Electron Microscopy (SEM) to assess its composition and structure. It was observed that the percentage composition of Alumina was increased from 30.53% to 77.28% and 83.00% at calcination temperatures of 800°C and 900°C respectively. This established that Alumina can be extracted from Kaolin clay.