Effect of diboron trioxide on the crushing strength and smelting mechanism of high-chromium vanadium–titanium magnetite pellets

Abstract

The effect of diboron trioxide (B₂O₃) on the crushing strength and smelting mechanism of high-chromium vanadium–titanium magnetite pellets was investigated in this work. The main characterization methods were X-ray fluorescence, inductively coupled plasma–atomic emission spectroscopy, mercury injection porosimetry, X-ray diffraction, metallographic microscopy, and scanning electron microscopy–energy-dispersive X-ray spectroscopy. The results showed that the crushing strength increased greatly with increasing B₂O₃ content and that the increase in crushing strength was strongly correlated with a decrease in porosity, the formation of liquid phases, and the growth and recrystallization consolidation of hematite crystalline grains. The smelting properties were measured under simulated blast furnace conditions; the results showed that the smelting properties within a certain B₂O₃ content range were improved and optimized except in the softening stage. The valuable element B was easily transformed to the slag, and this phenomenon became increasingly evident with increasing B₂O₃ content. The formation of Ti(C,N) was mostly avoided, and the slag and melted iron were separated well during smelting with the addition of B₂O₃. The size increase of the melted iron was consistent with the gradual optimization of the dripping characteristics with increasing B₂O₃ content.

Keywords

high-chromium vanadium–titanium magnetite / pellets / diboron trioxide / crushing strength / smelting mechanism

References

[1] Du H.G. Principle of Smelting Vanadium−Titanium Magnetite in the Blast Furnace, 1996, Beijing, Science Press 1.

[2] Cheng G.J., Xue X.X., Gao Z.X., Jiang T., Yang H., Duan P.N. Effect of Cr₂O₃ on the reduction and smelting mechanism of high-chromium vanadium−titanium magnetite pellets. ISIJ Int., 2016, 56(11): 1938.

[3] Cheng G.J., Xue X.X., Jiang T., Duan P.N. Effect of TiO2 on the crushing strength and smelting mechanism of high-chromium vanadium−titanium magnetite pellets. Metall. Mater. Trans. B, 2016, 47(3): 1713.

[4] Biswas A.K. Principles of Blast Furnace Ironmaking: Theory and Practice, 1981, Brisbane, Cootha Publishing House 38.

[5] Chun T.J., Zhu D.Q., Pan J. Influence of sulfur content in raw materials on oxidized pellets. J. Cent. South Univ. Technol., 2011, 18(6): 1924.

[6] Huang Y.F., Han G.C., Jiang T., Zhang Y.B., Li G.H. Oxidation and sintering characteristics of magnetite iron ore pellets balled with a novel complex binder. Miner. Process. Extr. Metall. Rev., 2013, 34(1): 42.

[7] Sivrikaya O., Arol A.I., Eisele T., Kawatra S.K. The effect of calcined colemanite addition on the mechanical strength of magnetite pellets produced with organic binders. Miner. Process. Extr. Metall. Rev., 2013, 34(4): 210.

[8] Gao Q.J., Shen Y.S., Wei G., Jiang X., Shen F.M. Diffusion behavior and distribution regulation of MgO in MgO-bearing pellets. Int. J. Miner. Metall. Mater., 2016, 23(9): 1011.

[9] Ou H.Z. Experimental Study on Reasonable Burden Structure of Blast Furnace for Smelting Imported High Chromium Vanadium−Titanium Magnetite, 2012, Shenyang, Northeastern University 38.

[10] Xu L.B. Experimental Study on Oxidized Pellets Preparation of Imported High Chromium Vanadium−Titanium Magnetite, 2012, Shenyang, Northeastern University 37.

[11] Tang J., Chu M.S., Feng C., Li F., Tang Y.T., Liu Z.G. Coupled effect of valuable components in high-chromium vanadium-bearing titanomagnetite during oxidization roasting. ISIJ Int., 2016, 56(8): 1342.

[12] Cheng G.J., Liu J.X., Liu Z.G., Chu M.S., Xue X.X. Non-isothermal reduction kinetics and mechanism of high chromium vanadium-titanium magnetite pellets. Ironmaking Steelmaking, 2015, 42(1): 17.

[13] Liu J.X., Cheng G.J., Liu Z.G., Chu M.S., Xue X.X. Reduction process of pellet containing high chromic vanadium− titanium magnetite in cohesive zone. Steel Res. Int., 2015, 86(7): 808.

[14] Chu M.S. Raw Fuels and Auxiliary Materials in Ferrous Metallurgy, 2010, Beijing, Metallurgical Industry Press 112.

[15] Zhang Y.M. Production Technology of Pellets, 2005, Beijing, Metallurgical Industry Press 179.

[16] Li H.M. Study on the Process and Mechanism of Improving the Pelletization of Brazilian Hematite by Adding Boron Bearing Compound Additives, 2009, Changsha, Central South University 30.

[17] Zhu D.Q., Zhou W.T., Pan J., Chen D. Improving pelletization of Brazilian hematite by adding boron-containing magnetite. J. Cent. South Univ. Sci. Technol., 2014, 45(2): 348.

[18] Ren S., Zhang J.L., Wu L.S., Liu W.J., Bai Y.N., Xing X.D., Su B.X., Kong D.W. Influence of B₂O₃ on viscosity of high Ti-bearing blast furnace slag. ISIJ Int., 2012, 52(6): 984.

[19] Cui C.M., Xu X.G., Zhang G.F., Liu S.L., Han W.R., Wang K.H. Determination of physical properties of melting boron-rich slags. J. Iron Steel Res., 1996, 8(2): 54.

[20] Gao Y.H. Study on Viscosity Characteristic and Microstructure of Blast Furnace Titanium Slag with Boron, 2012, Chongqing, Chongqing University 43.

[21] Zhang H.F. Research on the Production and Properties of Boron Steel Produced by Using Pig Iron Containing Boron as Alloying Agent, 2009, Shenyang, Northeastern University 8.

[22] Lang J.F., Ai Z., Zhang X.P. Basic principle and process characteristics of Fe–B separation in the comprehensive development process of paigeite with blast furnace method, Multipurpose Miner. Resour., 1996, 3, 1.