Utilization of red mud for extraction of alumina nanopowder

A huge amount of red mud as a common solid waste is generated during the alumina extraction in the Bayer process. The red mud is rich in valuable metals. The recovery of such metals has attracted the attention of many researchers. This study is devoted to the extraction of alumina nanopowder from red mud through a novel hydrometallurgy-based process. The process includes leaching, co-precipitation, re-dissolution, re-precipitation, washing, and calcination stages. The leaching stage was performed using 1 M oxalic acid under atmospheric pressure at 85 °C with a leaching time of 120 min and liquid-to-solid ratio of 20 ml/g. At the end of the process, the obtained aluminum hydroxide was calcined at 450 °C for 2 h to obtained alumina. The as-prepared alumina was characterized using XRD and FESEM techniques. The characterization results revealed that the as-prepared alumina is in nanoscale. Its morphological structure exhibited agglomerations of nanoparticles with the size ranged from 13 to 25 nm.

Keywords:

Alumina , Nano , Red mud , Waste recycling