Document Type : Original Research Paper


1 Minig, Metallurgy and Petroleum Enigineering Department, Amir Kabir University of Technology, Tehran, Iran

2 Geological Survey of Iran, Tehran, Iran


In this paper, iron removal studies on high iron diasporic bauxite by thermochemical treatment was investigated for the first time. For this purpose, bauxite samples were calcined in temperatures between 600 and 1100°C and then leached with hydrochloric acid. Obtained results revealed, in spit of gradual decrease in both iron and aluminum extraction with rising calcination temperature, iron extraction to aluminum extraction is selective at calcination temperature above 900°C. Leaching studies of calcined sample at 900°C proved that leaching temperature is the most important parameter for iron dissolution in acid and rising leaching temperatures from 20 to 95°C increases iron extraction over 70%. The other optimum parameters are: leaching time120 minutes, acid concentration 50% V/V, grinding size of 210 µm, pulp density of 15% solid by weight. As a result of optimizing parameters, 96.5% of bauxite iron content removed successfully with 88.5% aluminum recovery and solid residue iron content, i.e., the obtained concentrate, decreased from 27.02 to 1.59%.


Banerjee, G. N., 2000- “Deironation of bauxite by gaseous reduction and magnetic separation for refractory uses”, Transactions of the Indian Institute of Metals (India) Vol. 53, no. 4-5, pp: 527-529
Gholinejad, M., 2003- “Beneficiation of the low grade bauxite by wet high intensity  magnetic separation”, International seminar on mineral processing Technology- MPT,PP:243-249
Guanzhou, Qiu., 2004 - “Activation and removal of silicon by thermochemical process”, Scandinavian Journal of metallurgy, pp121-128
Kloprogge, J. T., 2002- “Thermal decomposition of bauxite minerals: infrared emission spectroscopy of gibbsite, boehmite and diaspore, Journal of materials science, pp:1121-1129
Mergen, A., 2004 - “Production of sintered high alumina refractories from Turkish   bauxite ore”, British ceramic transactions vol.103, no.1 pp: 42-48
Mergen, A., 2002- “Kinetics of leaching of boehmitic bauxite of Konya-Turkey with          hydrochloric acid”, Silicates industrials, pp: 75-80
Mehta, SK., 1992- “High-temperature solid-state transformations in jammu        bauxite, journal of thermal analysis”, pp: 2455-2458
Pang, S.,1999- “Apparent kinetics of leaching of iron oxides in diasparic bauxite by             hydrochloric acid”, Nonferrous Metals China,Vol. 51, pp: 49-53
Paspaliaris, Y., 1987- “Reaction kinetics for the leaching of iron oxides in diasporic bauxite from the parnassus-giona zone (Greece) by hydrochloric acid” Hydrometallurgy, pp: 259-266 
Reddy, B. R., 1999- “Kinetics of leaching of gibbsitic bauxite with hydrochloric acid”, Hydrometallurgy 51, pp:131-138 
Rao, R. B., 2002- “Effect of thermal pretreatment on grindability and  upgradation of bauxite for refractory applications”, Light Metals  TMS Annual  Meeting, pp: 205-208
RaJ, D., 2004 - “High temperature transformation of Iron Minerals in bauxite”,  Hyperfine Interactions, pp:153-158
Sadler, L.Y.,1990 - “Process for enhanced removal of iron from bauxite ores”, SME Annual Meeting , pp. 233-246.
Zivkovic, Z. D., 1994 - Kinetics and mechanism of leaching of low-quality boehmite bauxite with hydrochloric acid,  Hydrometallurgy Vol. 36, pp. 247-258
Rayzman, V.L., 2003- “Extracting Silica and Alumina from low grade bauxite”, JOM pp: 47-50
Zhou, Q, S., 2004 - “Temperature dependence of crystal structure of roasted diasporic bauxite”,Transactions of nonferrous metals society of China 14 (1),pp: 180-183