Effect of Cr₂O₃ addition on oxidation induration and reduction swelling behavior of chromium-bearing vanadium titanomagnetite pellets with simulated coke oven gas

Abstract

The oxidation induration and reduction swelling behavior of chromium-bearing vanadium titanomagnetite pellets (CVTP) with Cr₂O₃ addition were studied, and the reduction swelling index (RSI) and compressive strength (CS) of the reduced CVTP with simulated coke oven gas (COG) injection were investigated. The results showed that the CS of the CVTP decreases and the porosity of the CVTP increases with increasing amount of Cr₂O₃ added. The Cr₂O₃ mainly exists in the form of (Cr, Fe)₂O₃ solid solution in the CVTP and as Fe-Cr in the reduced CVTP. The CS of the reduced CVTP increases and the RSI of the reduced CVTP decreases with increasing amount of Cr₂O₃ added. The limited aggregation and diffusion of metallic iron contribute to the formation of dense lamellar crystals, which leads to the slight decrease for reduction swelling behavior of reduced CVTP. This work provides a theoretical and technical basis for the utilization of CVTP and other Cr-bearing ores such as chromite with COG recycling technology.

Keywords

chromium oxide / oxidation induration / reduction swellability / coke oven gas / chromium-bearing vanadium titanomagnetite pellets

References

[1] Tan XC, Li H, Guo JX, Gu BH, Zeng Y. Energy-saving and emission-reduction technology selection and CO₂ emission reduction potential of china’s iron and steel industry under energy substitution policy. J. Cleaner Prod., 2019, 222, 823.

[2] Mousa EA, Babich A, Senk D. Enhancement of iron ore sinter reducibility through coke oven gas injection into the modern blast furnace. ISIJ Int., 2013, 53(8): 1372.

[3] Liu ZG, Chu MS, Guo T, Wang HT, Fu X. Numerical simulation on novel blast furnace operation of combining coke oven gas injection with hot burden charging. Ironmaking Steelmaking, 2016, 43(1): 64.

[4] Wang HT, Chu MS, Guo TL, Zhao W, Feng C, Liu ZG, Tang J. Mathematical simulation on blast furnace operation of coke oven gas injection in combination with top gas recycling. Steel Res. Int., 2016, 87(5): 539.

[5] Nishioka K, Ujisawa Y, Tonomura S, Ishiwata N, Sikstrom P. Sustainable aspects of CO₂ ultimate reduction in the steelmaking process (COURSE50 Project), Part 1: Hydrogen reduction in the blast furnace. J. Sustainable Metall., 2016, 2(3): 200.

[6] Mousa EA, Babich A, Senk D. Reduction behavior of iron ore pellets with simulated coke oven gas and natural gas. Steel Res. Int., 2013, 84(11): 1085.

[7] Tang J, Chu MS, Feng C, Li F, Tang YT, Liu ZG. Coupled effect of valuable components in high-chromium vanadium-bearing titanomagnetite during oxidization roasting. ISIJ Int., 2016, 56(8): 1342.

[8] Cheng GJ, Gao ZX, Yang H, Xue XX. Effect of diboron trioxide on the crushing strength and smelting mechanism of high-chromium vanadium-titanium magnetite pellets. Int. J. Miner. Metall. Mater., 2017, 24(11): 1228.

[9] Cheng GJ, Xue XX, Gao ZX, Jiang T, Yang H, Duan PN. Effect of Cr₂O₃ on the reduction and smelting mechanism of high-chromium vanadium-titanium magnetite pellets. ISIJ Int., 2016, 56(11): 1938.

[10] Jena BC, Dresler W, Reilly IG. Extraction of titanium, vanadium and iron from titanomagnetite deposits at pipestone lake, Manitoba, Canada. Miner. Eng., 1995, 8(1–2): 159.

[11] Cheng GJ, Gao ZX, Yang H, Xue XX. Effect of calcium oxide on the crushing strength, reduction, and smelting performance of high-chromium vanadium-titanium magnetite pellets. Metals, 2017, 7(5): 181.

[12] Cheng GJ, Xue XX, Jiang T, Duan PN. 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.

[13] Li W, Fu GQ, Chu MS, Zhu MY. Influence of Cr₂O₃ gas-based direct reduction behavior of Hongge vanadium titanomagnetite pellet with simulated shaft furnace gases. ISIJ Int., 2018, 58(4): 604.

[14] Li W, Wang N, Fu G, Chu MS, Zhu MY. Effect of Cr₂O₃ addition on the oxidation induration mechanism of Hongge vanadium titanomagnetite pellet. Int. J. Miner. Metall. Mater., 2018, 25(4): 391.

[15] Feng C, Chu MS, Tang J, Liu ZG. Effects of smelting parameters on the slag/metal separation behaviors of Hongge vanadium-bearing titanomagnetite metallized pellets obtained from the gas-based direct reduction process. Int. J. Miner. Metall. Mater., 2018, 25(6): 609.

[16] Zhang YM. Pellet Production Technology, 2005, Beijing, The Metallurgy Industry Press 67.

[17] Orowan E. Fracture and strength of solids. Rep. Prog. Phys., 1949, 12(1): 185.

[18] Spriggs RM. Expression for effect of porosity on elastic modulus of polycrystalline refractory materials, particularly aluminum oxide. J. Am. Ceram. Soc., 1961, 44(12): 628.

[19] Zhu DQ, Yang CC, Pan J, Zhang Q, Shi BJ, Zhang F. Insight into the consolidation mechanism of oxidized pellets made from the mixture of magnetite and chromite concentrates. Metall. Mater. Trans. B, 2016, 47(2): 1010.

[20] Friel JJ, Erickson ES. Chemistry, microstructure, and reduction characteristics of dolomite-fluxed magnetite pellets. Metall. Trans. B, 1980, 11(2): 233.

[21] Liu YC, Nachimuthu S, Chuang YC, Ku Y, Jiang JC. Reduction mechanism of iron titanium based oxygen carriers with H₂ for chemical looping applications-a combined experimental and theoretical study. RSC Adv., 2016, 6(108): 106340.

[22] Sharma T, Gupta RC, Prakash B. Effect of firing condition and ingredients on the swelling behaviour of iron ore pellets. ISIJ Int., 1993, 33(4): 446.

[23] Sharma T, Gupta RC, Prakash B. Swelling of iron ore pellets by statistical design of experiment. ISIJ Int., 1992, 32(12): 1268.

[24] Seaton CE, Foster JS, Velasco J. Structural changes occurring during reduction of hematite and magnetite pellets containing coal char. Trans. Iron Steel Inst. Jpn., 1983, 23(6): 497.

[25] Wang HT, Sohn HY. Effects of firing and reduction conditions on swelling and iron whisker formation during the reduction of iron oxide compact. ISIJ Int., 2011, 51(6): 906.

[26] Yi LY, Huang ZC, Jiang T, Wang LN, Qi T. Swelling behavior of iron ore pellet reduced by H₂-CO mixtures. Powder Technol., 2015, 269, 290.