The Research on Ammonium Salt was used to Remove Sodium from Fly Ash Red Mud

Abstract

Red mud or bauxite residue is a waste or by- product produced from the alumina industry. With the rapid development of alumina industry, the comprehensive utilization of red mud has not been resolved for a long time ,it seriously polluted the environment and led to a waste of resources.In the present work, the ammonium salts were used to remove sodium from fly ash red mud. Using red mud with acid and ammonium nitrate, ammonium reaction freed, nitrate are combined into soluble salt with metal ions. The reaction time, reaction temperature, liquid-solid ratio and ammonium salt/Na2O ration were studied. The optimal reaction conditions are: reaction time is 80 min, reaction temperature is 60℃, liquid-solid ratio is 6 and ammonium salt- Na2O ratio is 1.5 for NH4NO3 and (NH4)2CO3, respectively. NH4NO3 have a better property for removing sodium than (NH4)2CO3. Both of them can achieve the requirement that make the sodium content below 2w%, and accord with the requirement for building materials.