Kinetic analysis of alumina leaching from calcined Owhe kaolinite in HNO₃ and H₂O₂ solution

In this work, the feasibility of nitric acid (HNO₃) and hydrogen peroxide (H₂O₂) binary solution as a leachant for alumina leaching from Owhe kaolinite was examined. The leaching was carried out by batch process. Least squares method was deployed to examine the experimental results. The results show that the percentage of alumina dissolved recorded an increase with increase in the concentration of H₂O₂ and temperature and recorded a reduction with increase in solid/liquid (S/L) ratio and particle size. Chemical reaction was established as the rate-determining step. About 89% alumina was leached on the average with activation energy (E_a) of 4.406 kJ/mol while the overall rate constant was 1.067 s⁻¹. A binary solution of HNO₃ and H₂O₂ showed viability for Owhe kaolinite leaching. Analysis of residue remaining after leaching by energy dispersive spectrometer (EDS) showed the major elements found in the residues as silicon, aluminum, and titanium.