Analysis of Alkali in Bayer Red Mud: Content and Occurrence State in Different Structures

The application of large amounts red mud in the field building materials is one main ways to reuse this material, but high alkali content limits its application. In paper, washable alkali, removable and lattice contents Bayer were studied, occurrence states potassium sodium studied using XRD, IR, XPS, NMR. On basis, removal mechanism for was analyzed. results showed that Na mainly deposited shelf silicon voids hydroxy sodalite (Na8(AlSiO4)6(OH)2(H2O)2) form Si-O-Na or Al-O-Na. K silico-oxygen void feldspar (KAlSi3O8) Si-O-K Al-O-K. 13.7% 4.47%; agent CaO removed 83.1% 50.8% mud; 3.20% 44.8%, respectively. process dealkalization, Ca2+ ions can enter internal hydroxyl silica skeleton then replace Al3+ Si-O Na+ K+ voids. replacement reaction changes tetrahedron network structure, resulting disintegration frame-like feldspar, forming an isolated, island-like hydrated garnet.