Mineralogical and sink-float studies of Jajarm low-grade bauxite

Abstract

Jajarm’s bauxite deposits are mainly diasporic, and they have a low mass ratio of Al₂O₃/SiO₂. It is necessary to increase the run-of-mine mass ratio before feeding the material to the Bayer process. Chemical analysis indicated that the low-grade bauxite sample from Jajarm contained 43.9wt% Al₂O₃ and 13.35wt% SiO₂, resulting in a mass ratio of 3.29. According to mineralogical studies, the presence of aluminosilicate minerals such as kaolinite, illite, and quartz was the main reason for the decrease of the mass ratio. Microscopic observations revealed that, with the size reduction from −1000+710 to −38 μm, the liberation degree of diaspore increased from 10% to 60%, and that of aluminosilicates increased from 20% to 85%. Heavy liquids with the densities of 2.8, 3.0, 3.2, and 3.4 g/cm³ were used to evaluate the heavy media separation in three sizes, i.e., −3350+710, −710+212, and −212+125 μm. Laboratory studies confirm that the density of 3.2 g/cm³ can produce the concentrates (in sunk fractions) with recoveries of 89.09%, 91.24%, and 84.68% with the Al₂O₃/SiO₂ mass ratios of 5.03, 5.16, and 5.15 for the −3350+710, −710+212, and −212+125 μm sizes, respectively.

Keywords

bauxite / diaspore / aluminosilicate / mass ratio / heavy media

References

[1] J. Leonard, Bauxite, [in] Proceeding of Bauxite Symposium, Los Angles, 1984, p.1.

[2] U.S. Geological Survey, Mineral Commodity Summaries, 2008, p.29.

[3] Xu Z., Plitt V., Liu Q. Recent advances in reverse flotation of diasporic ores—A Chinese experience. Miner. Eng., 2004, 9–10, 1007.

[4] Lu Y.P., Zhang G.F., Feng Q.M., Ou L.M. A novel collector RL for flotation of bauxite. J. Cent. South Univ. Technol., 2002, 11(3): 21.

[5] Wang Y., Hu Y., He P., Gu G. Reverse flotation for removal of silicates from diasporic-bauxite. Miner. Eng., 2004, 17, 63.

[6] Wang Y.H., Hu Y.H., Liu X.W. Flotation de-silicating from diasporic-bauxite with cetyl trimethylammonium bromide. J. Cent. South Univ. Technol., 2003, 10(4): 324.

[7] Chen X., Hu Y., Wang Y., Xiong D. Effects of sodium hexametaphosphate on flotation separation of diaspore and kaolinite. J. Cent. South Univ. Technol., 2005, 12(4): 420.

[8] Zhao S.G., Zhong H., Liu G.Y. Effects of quaternary ammonium salts on flotation behavior of aluminosilicate minerals. J. Cent. South Univ. Technol., 2007, 14(4): 500.

[9] Li H., Hu Y., Wang D., Xu J. Effect of hydroxamic acid polymers on reverse flotation of bauxite. J. Cent. South Univ. Technol., 2004, 11(3): 291.

[10] Hu Y., Liu X., Xu Z.H. Role of crystal structure in flotation separation of diaspore from kaolinite, pyrophyllite and illite. Miner. Eng., 2003, 16, 219.

[11] Mirmohamadsadeghi A., Aali H. Review of Aluminum Metal, 1995 Tehran, Imam Hussein University, 18.

[12] Rezai B. Mineral Processing Technology: Gravity Separation, 1998 Bandar Abbas, Hormozgan University Publication

[13] P. Fang, C. Jia, W. Liu, and C. Han, Beneficiation of low-grade diasporic bauxite with hydrocyclone, Trans. Nonferrous Met. Soc. China, (2008), p.444.

[14] McCormick P.G., Picaro T., Smith P.A.I. Mechanochemical treatment of high silica bauxite with lime. Miner. Eng., 2002, 15, 211.

[15] B.A. Wills and T.J. Napier Munn, Mineral Processing Technology, Elsevier Science & Technology Books, 2006, p.246.