Effects of MgO on densification and consolidation of oxidized pellets

Abstract

The calcined magnesite was utilized as a kind of MgO bearing additive to produce MgO bearing pellets. The effects of MgO on densification and consolidation of pellets were investigated. The experimental results show that, at the same process parameters, the porosity and pore size distribution of green pellets have no evident relation with the MgO bearing additive, pore size of green pellets is between 15 μm and 35 μm and the porosity of green pellets is about 34%. There is a densification and consolidation phenomenon during the induration process; the pore size and porosity of product pellets decrease gradually; and the structure of product pellets becomes dense. MgO makes a negative effect on the densification and consolidation of product pellets, the densification ratio of pellets decreases from 46.3% to 28.6% with the addition of MgO bearing additive from 0 to 2.0 %. The porosity and the pore size of product pellets increase gradually with the increase of MgO content; When the mass fraction of MgO bearing additive increases from 0 to 2.0%, the pore size of product pellet increases and the pore size distributes in a large range. Also, the porosity increases from 18.61% to 24.06%.

Keywords

MgO / oxidized pellets / densification / porosity / pore size

References

[1] ZhouC-dianTechnical manual of blast furnace production [M], 2003, Beijing, Metallurgical Industry Press: 50-60

[2] FuJ-y, ZhuD-qingBasic principles, techniques and equipment of the iron ore oxidized pellets [M], 2005, Changsha, Central South University Press: 323-336

[3] ShenF M, JiangX, WuG S. Proper MgO addition in blast furnace operation [J]. ISIJ International, 2006, 46(1): 65-69

[4] ShenF M, WuG S, JiangX. A new process of proper MgO addition in blast furnace operation [C]. Tohoku University. Proceedings of Commemorative International Symposium on Iron making Process and Environment. Sendai, 200528-33

[5] ZhouG-f, YangFu. Effects of adding MgO on pelletizing ability and strength of pellet [J]. Research on Iron and Steel, 2009, 37(2): 10-13

[6] ChunT-j, ZhuD-q, PanJian. Influence of sulfur content in raw materials on oxidized pellets [J]. Journal of Central South University of Technology, 2011, 18(6): 1924-1929

[7] LiS-h, ChenT-j, ZhangY-m, ZhaoJie. Experimental study on application of Mg-bearing additive in iron ore pellet [J]. Sintering and Pelletizing, 2011, 36(1): 33-37

[8] ZhangL-g, ZhangZ-w, RenT-xu. Study on compound dolomite flux on pellet in ansteel [J]. China Metallurgy, 2011, 21(8): 34-38

[9] GaoQ-j, WeiG, HeY-b, ShenF-man. Effect of MgO on compressive strength of pellet [J]. Journal of Northeastern University (Natural Science), 2013, 34(1): 103-106

[10] SzekelyJ, EvansJ W, SohnH YGas-solid reductions [M], 1976, NewYork, Academic Press: 97-105

[11] ChenY-m, LiJian. Crystal rule of Fe2O3 in oxidized pellet [J]. Journal of Central South University of Technology, 2007, 38(1): 70-73

[12] LooC E, WanK T, HowesV R. Mechanical properties of natural and synthetic mineral phases in sinters having varying reduction degradation indices [J]. Ironmaking and Steelmaking, 1998, 25(6): 279-285

[13] MatsumuraM, HoshiM, KawaguchiT. Improve of sinter softening property and reducibility by controlling chemical compositions [J]. ISIJ International, 2005, 45(4): 598-607

[14] KasaiE, SakanoY, KawaguchiaT. Influence of properties of fluxing materials on the flow of melt formed in the sintering process [J]. ISIJ International, 2000, 40(9): 857-862

[15] GaoQ-j, WenQ-L, WeiG, JiangX, ShenF-man. Study on the effect of caustic calcined magnesite to quality of green-Pellets [C]. Northeastern University. The 4th Australia-China-Japan Symposium on Iron and Steelmaking, 201250-53

[16] KhakiJ, KashiwaY, IshiiK. High temperature behavior of self fluxed pellets during heating up reduction [J]. Ironmaking and Steelmaking, 1994, 21(1): 56-63

[17] ShenF-m, GaoQ-j, WeiG, DingZ-min. Effect of MgO-bearing additive on metallurgical property of pellets [C]. Chinese Society of Metals. Asia Steel International Conference 2012, 201219-24