Recycling of alum sludge for alpha al2o3 production using different chemical treatments

Abstract

The present work focused on recycling the alum sludge which is one of the serious problems during the production of potable water. In this work, the alumina was extracted from alum sludge by using different chemical treatment methods after subjecting to different thermal treatments. XRD, XRF, SEM, TEM, IR and surface area measurements were used to detect the properties of the obtained alumina. Alpha alumina was obtained at 1400°C after treatment by NaOH followed by ammonium acetate as a precipitating agent for Al(OH)3 or by direct addition of NH4 OH in one step method at pH 5.5–6. On the contrary, the treatment by NaOH followed by NaHCO3 for precipitation of Al(OH)3 led to the formation of sodium aluminate beside low percentage of alpha alumina after the heat treatment.