Assessment of blast furnace behaviour through softening–melting test

Abstract

Blast furnace operation is a complex phenomenon; maximising productivity requires a balance of burden characteristics. Meeting the targets of optimum sinter strength and minimum slag volume is a matter of concern for high alumina (2 . 0-2 . 1%) iron ore fines. To achieve reduced slag volume MgO in the sinter may be reduced and sinter strength maintained by addition of coke breeze. However, the associated increase in fuel rate during sintering raises the FeO content. The effects of increasing FeO and lowering MgO on the softening melting behaviour of burden materials have been assessed in laboratory experiments and the results compared with data from blast furnace operations at Tata Steel. It was found that with sinter containing .12%FeO, erratic furnace behaviour was encountered and energy adjustment was required with the reduction in MgO (1 . 77-1 . 48%) to ensure smooth operation.

Evaluating the Reduction-Softening Behaviour of Blast Furnace Burden with an Advanced Test

“…Another weakness is that some softening studies comprise only an individual pellet 16,17) or a couple of pellets 2,3,[9][10][11][12][13][14][15]18) instead of a packed bed of pellets. 7,8,[19][20][21][22][23][24][25][26][27][28][29][30] Studies 2,7,[21][22][23][24][25][26][27][28][29] have been carried out for iron ore pellets under load dynamically from ambient temperature to elevated temperatures using a simulated BF gas. Recently, Guha and Sinha 29) presented a modified softening-melting test with a possibility to use a gas composition varying with temperature/time to better simulate the actual conditions in a BF.…”

Tracking Softening-Melting Behaviour of Blast Furnace Burden

“…4) Reducing gas mix is used at a flow rate of 6 liters per minute. Softening-melting behavior of burden mix is normally characterized by: softening temperature (Ts), temperature in °C at which the pressure differential across the bed is 100 mmWC (mm Water Column); melting temperature (Tm), temperature in °C at which the pressure drop across bed again is back to 100 mmWC; ΔPmax, the maximum pressure differential across the bed in mmWC (as shown in Fig.…”

Three dimensional mathematical model of the iron ore sintering process based on multiphase theory

“…The solid diameters and shape factors are given as raw materials properties from the harmonic average of the particle size distributions. In the present model these parameters are calculated by using soft-melting experimental data for the raw materials used 8,[16][17][18][19][20] , as presented by Equations 7-9.…”

“…As softening-meting data the model uses the parameters T im , ∆T m and S m representing the initial melting temperature, meting temperature interval and percentage of shrinkage. This parameters are obtained from the pressure vs temperature curve obtained from the softening-melting experiment [16][17][18][19][20] .…”

“…The solid phase accounts for the mixture of iron ore sinter feed, fine sinter(returned fine sinter), coke breeze(or other solid fuel), scales(fines from steel plant), fluxes and limestone. The liquid phase is composed of melted and formed components in the liquid phase [10][11][12][13][14][15][16][17][18][19][20] . The re-solidified phase comprises the liquids re-solidified and phases formed during the re-solidification process and strongly depends on the local liquid composition and heat exchange.…”