Reduction–melting behaviors of boron-bearing iron concentrate/carbon composite pellets with addition of CaO

Abstract

Although the total amount of boron resources in China is high, the grades of these resources are low. The authors have already proposed a new comprehensive utilization process of boron-bearing iron concentrate based on the iron nugget process. The present work describes a further optimization of the conditions used in the previous study. The effects of CaO on the reduction–melting behavior and properties of the boron-rich slag are presented. CaO improved the reduction of boron-bearing iron concentrate/carbon composite pellets when its content was less than 1wt%. Melting separation of the composite pellets became difficult with the CaO content increased. The sulfur content of the iron nugget gradually decreased from 0.16wt% to 0.046wt% as the CaO content of the pellets increased from 1wt% to 5wt%. CaO negatively affected the iron yield and boron extraction efficiency of the boron-rich slag. The mineral phase evolution of the boron-rich slag during the reduction–melting separation of the composite pellets with added CaO was also deduced.

Keywords

iron concentrate / boron / ore reduction / composite pellets / calcium oxide

References

[1] Quan Y. Research and Development of Boron and Boron Compounds, 2008, Dalian, Dalian University of Technology Press, 1.

[2] Zhang X.P., Lang J.F., Cui C.M., Liu S.L. Comprehensive utilization of low grade ludwigite ore with blast furnace smelting. Iron Steel, 1995, 30(12): 9.

[3] Wang G., Wang J.S., Ding Y.G., Ma S., Xue Q.G. New separation method of boron and iron from ludwigite based on carbon bearing pellet reduction and melting technology. ISIJ Int., 2012, 52(1): 45.

[4] Wang G., Ding Y.G., Wang J.S., She X.F., Xue Q.G. Effect of carbon species on the reduction and melting behavior of boron-bearing iron concentrate/carbon composite pellets. Int. J. Miner. Metall. Mater., 2013, 20(6): 522.

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

[6] Li Y.L., Yang J.H., Gao J.S. Effect of alkali earth metal oxides on kinetic parameters of coke solution loss reaction. J. Fuel Chem. Technol., 2001, 29(3): 280.

[7] Yang X.M., Xie Y.S., Wang D.G., Huang D.B., Kong L.T., Yang T.J. Effect of CaO and CaCO3 on reduction rate of iron ore pellets containing carbon. J. Iron Steel Res. Int., 2000, 7(2): 1.

[8] Allibert M. Slag Atlas, 1995, Düsseldorf, Verlag Stahleisen GmbH, 126.

[9] Matsui T., Ishiwata N., Hara Y., Takeda K. Influence of gangue composition on melting behavior of coal-reduced iron mixture. ISIJ Int., 2004, 44(12): 2105.

[10] Satoh K., Noguchi T., Hino M. Reduction and carburization of iron oxide by carbonaceous materials. Steel Res. Int., 2010, 81(10): 834.

[11] Kim H.S., Kim J.G., Sasaki Y. The role of molten slag in iron melting process for the direct contact carburization: wetting and separation. ISIJ Int., 2010, 50(8): 1099.

[12] Kim H.S., Kang Y.B., Kim J.G., Sasaki Y. The role of iron oxide bearing molten slag in iron melting process for the direct contact carburization. ISIJ Int., 2011, 51(1): 166.