Towards the Zeolitization of Bauxite: Thermal Behaviour of Gibbsite in High-Alumina- Ghanaian Bauxite.

Abstract

Bauxite samples from Awaso mines in Ghana were heated at 100, 300, 500, 800 and 1000 oC and changes in the Al2O3.H2O phase/composition were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), Fourier transformed infrared spectroscopy (FTIR) and particle size analysis. The thermal behaviour of bauxite with time was monitored by Thermogravimetric analysis. The results obtained showed that heating bauxite at 100 oC is enough to obtain the sodalite structure needed for the zeolitization of bauxite. Heating the bauxite at higher temperatures resulted in the loss of the alumina composition as a result of decomposition of metal carbonates to metal oxides and subsequently the formation of a metal aluminosilicate. The particles size decreased with temperature with average particle size distribution ranging from 8 – 10 μm and 15.5 – 42 μm in the un-heated and treated bauxite respectively.