Alumina Extraction from Red Mud by Magnetic Separation

Suprapto Suprapto (Department of Chemistry, Faculty of Science, Institut Teknologi Sepuluh Nopember, Keputih, Sukolilo, Surabaya 60111, Indonesia)
Zahrotul Istiqomah (Department of Chemistry, Faculty of Science, Institut Teknologi Sepuluh Nopember, Keputih, Sukolilo, Surabaya 60111, Indonesia)
Eko Santoso (Department of Chemistry, Faculty of Science, Institut Teknologi Sepuluh Nopember, Keputih, Sukolilo, Surabaya 60111, Indonesia)
Ahmad Anwarud Dawam (Department of Chemistry, Faculty of Science, Institut Teknologi Sepuluh Nopember, Keputih, Sukolilo, Surabaya 60111, Indonesia)
Didik Prasetyoko (Department of Chemistry, Faculty of Science, Institut Teknologi Sepuluh Nopember, Keputih, Sukolilo, Surabaya 60111, Indonesia)

Indonesian Journal of Chemistry
Vol 18, No 2 (2018)

Alumina extraction from red mud has been investigated by magnetic separation with three-step treatment. First, the addition of red mud with Na2CO3 (12 wt%) and heated at 110 °C for 4 h. The second step was carbon reduction using coal with mass ratio of (red mud+Na2CO3) : coal was 1:3 then roasted at temperature of 850, 950, and 1050 °C for 1, 2, and 3 h. The third step was magnetic separation. The magnetic separation was carried out in order to remove magnetite produced during roasting process. Magnetic and non-magnetic phases obtained were characterized by XRD and SEM-EDX techniques. The non-magnetic phase obtained was leached using HCl 6 M, and then aluminum content was determined by Inductively Coupled Plasma (ICP). The result revealed that the highest aluminum oxide extracted from the red mud was 20.66 wt% obtained by roasting at temperature of 1050 °C for 2 h.