Recovery of iron and calcium aluminate slag from high-ferrous bauxite by high-temperature reduction and smelting process

Abstract

A high-temperature reduction and smelting process was used to recover iron and calcium aluminate slag from high-ferrous bauxite. The effects of w(CaO)/w(SiO₂) ratio, anthracite ratio, and reduction temperature and time on the recovery and size of iron nuggets and on the Al₂O₃ grade of the calcium aluminate slag were investigated through thermodynamic calculations and experiments. The optimized process conditions were the bauxite/anthracite/slaked lime weight ratio of 100:16.17:59.37, reduction temperature of 1450°C and reduction time of 20 min. Under these conditions, high-quality iron nuggets and calcium aluminate slag were obtained. The largest size and the highest recovery rate of iron nuggets were 11.42 mm and 92.79wt%, respectively. The calcium aluminate slag mainly comprised Ca₂SiO₄ and Ca₁₂Al₁₄O₃₃, with small amounts of FeAl₂O₄, CaAl₂O₄, and Ca₂Al₂SiO₇.

Keywords

bauxite / reduction / smelting / recovery rate / calcium aluminate / slag

References

[1] Liu X. F., Wang Q. F., Zhang Q. Z., Feng Y. W., Cai S. H. Mineralogical characteristics of the super large quaternary bauxite deposits in Jingxi and Debao counties, western Guangxi, China. J. Asian Earth Sci., 2012, 52, 53.

[2] Wang R. H., Li M., Chen D. X. Resource potential prediction for lateritic high-iron gibbsite bauxite deposits in Guangxi. Geol. Bull. China, 2011, 30(8): 1303.

[3] Wang Q. F., Deng J., Liu X. F., Zhang Q. Z., Sun S. L., Jiang C. Z., Zhou F. Discovery of the REE minerals and its geological significance in the Quyang bauxite deposit, West Guangxi, China. J. Asian Earth Sci., 2010, 39(6): 701.

[4] Chehreh Chelgani S., Jorjani E. Artificial neural network prediction of Al²O₃ leaching recovery in the Bayer process–Jajarm alumina plant (Iran). Hydrometallurgy, 2009, 97(1-2): 105.

[5] Smith P. The processing of high silica bauxites: review of existing and potential processes. Hydrometallurgy, 2009, 98, 162.

[6] Bolsaitis P., Chang V., Schorin H., Aranguren R. Beneficiation of ferruginous bauxites by high-gradient magnetic separation. Int. J. Miner. Process., 1981, 8(3): 249.

[7] Massola C. P., Chaves A. P., Lima J. R. B., Andrade C. F. Separation of silica from bauxite via froth flotation. Miner. Eng., 2009, 22(4): 315.

[8] Michail S., Maria T., Petros E. T., Konstantinos P. Greek “red mud” residue: a study of microwave reductive roasting followed by magnetic separation for a metallic iron recovery process. J. Hazard. Mater., 2013, 254-255, 193.

[9] Liu Y. Y., Zhao B. C., Tang Y., Wan P. Y., Chen Y. M., Lv Z. J. Recycling of iron from red mud by magnetic separation after co-roasting with pyrite. Thermochem. Acta, 2014, 588, 11.

[10] Zhao A. C., Liu Y., Zhang T. A., Lü G. G., Dou Z. H. Thermodynamics study on leaching process of gibbsite bauxite by hydrochloric acid. Trans. Nonferrous Met. Soc. China, 2013, 23, 266.

[11] Cao S. T., Zhang Y. F., Zhang Y. Preparation of sodium aluminate from the leach liquor of diasporic bauxite in concentrated NaOH solution. Hydrometallurgy, 2009, 98(3-4): 298.

[12] R Reddy B., K Mishra S., Banerjee G. N. Kinetics of leaching of a gibbsite bauxite with hydrochloric acid. Hydrometallurgy, 1999, 51, 131.

[13] Wang Y., Hu Y., He P., Gu G. Reverse flotation for removal of silicates from diasporic-bauxite. Miner. Eng., 2004, 17(1): 63.

[14] Zhai X. J., Li N. J., Zhang X., Fu Y., Jiang L. Recovery of cobalt from converter slag of Chambishi Copper Smelter using reduction smelting process. Trans. Nonferrous. Met. Soc. China, 2011, 21(9): 2117.

[15] Ishiwata N., Sawa Y., Hiroha H., Matsui T., Murao A., Higuchi T., Takeda K. Investigation of reduction and smelting mechanism in the Hi-QIP process. Steel Res. Int., 2009, 80(8): 523.

[16] Kapure G. U., Rao C. B., Tathavadkar V. D., Sen R. Direct reduction of low grade chromite overburden for recovery of metals. Ironmaking Steelmaking, 2011, 38(8): 590.

[17] Ding Y. G., Wang J. S., Wang G., Ma S., Xue Q. G. Comprehensive utilization of paigeite ore using iron nugget making process. J. Iron Steel Res. Int., 2012, 19(6): 9.

[18] Guo Y. H., Gao J. J., Xu H. J., Zhao K., Shi X. F. Nuggets production by direct reduction of high iron red mud. J. Iron Steel Res. Int., 2013, 20(5): 24.

[19] Yu H. Y., Pan X. L., Ding T. T., Zhang W., Liu H., Bi S. W. Adsorption of sodium polyacrylate at interface of dicalcium silicate–sodium aluminate solution. Trans. Nonferrous. Met. Soc. China, 2011, 21(10): 2323.

[20] Wang B., Sun H. L., Guo D., Zhang X. Z. Effect of Na2O on alumina leaching property and phase transformation of MgO-containing calcium aluminate slags. Trans. Nonferrous Met. Soc. China, 2011, 21(12): 2752.

[21] Yu H. Y., Pan X. L., Wang B., Zhang W., Sun H. L., Bi S. W. Effect of Na2O on formation of calcium aluminates in CaO-Al²O₃-SiO₂ system. Trans. Nonferrous. Met. Soc. China, 2012, 22(12): 3108.

[22] Sun H. L., Wang B., Zhang J. X., Zong S. F., Liu J. J. Secondary reaction mechanism of leaching process of calcium aluminate slag. Trans. Nonferrous Met. Soc. China, 2015, 25(4): 1334.

[23] Li M., Peng B., Chai L. Y., Peng N., Yan H., Hou D. K. Recovery of iron from zinc leaching residue by selective reduction roasting with carbon. J. Hazard. Mater., 2012, 237-238, 323.

[24] Satoh K., Noguchi T., Hino M. Reduction and carburization of iron oxide by carbonaceous materials. Steel Res. Int., 2010, 81, 834.