Direct alkaline leaching of mechanically activated diasporic bauxite

Abstract

Diasporic bauxite from the Mugla-Milas region was mechanically activated in a planetary mill for different activation times and the structural changes were examined by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and specific surface area analysis (BET - Burnauer, Emmett and Teller). Non-activated and activated bauxite samples were leached directly in alkaline (Na(2)O) solution at atmospheric conditions and the activation procedure led to the amorphization and structural disordering of the diasporic bauxite structure, which increased the dissolution efficiency. Effects of milling speed, liquid/bauxite ratio and leaching time on alumina extraction in direct alkaline leaching of diasporic bauxite were also studied. The alumina extraction was similar to 7% for non-activated bauxite and similar to 70% for activated (7-5 minute) bauxite.