Alkali fusion of bauxite refining residue (red mud-RM) to produce low carbon cements

Abstract This paper creates hydraulic binders using waste and a low energy input. Cements are produced with bauxite refining residue (red mud-RM), blended limestone lime, fused at temperatures from 600 to 1200 °C. The Saudi RM investigated has significant Al Si but Ca. Therefore, lime (CaO) (CaCO 3 ) used, as source of calcium, harvest cementing hydrates.When calcining alone, reactive aluminium phases begin form c.300 However, c.900 °C, they turn into crystalline corundum (Al 2 O ), more stable less phase. It is hoped that the Ca provided by lime/limestone will react in during fusion, silicates aluminates rather than inert corundum. Both types fusion calcium properties. required higher temperature. Limestone produces lower temperature due decomposition CaCO when compared CaO. High break down CaO (melting point = 2572 °C), whereas decomposes °C disappears 850 Despite top alkali being much melting point, results demonstrate was released entered reactions forming aluminates. probably high content acting flux lowering