Physical properties of BOS slags

Mills, Kenneth C.; Keene, B. J.

doi:10.1179/095066087790150296

Cited by 249 publications

(185 citation statements)

References 73 publications

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“…In order to calculate the values for the molar volume of CaO, SiO 2 , FeO, MgO, and TiO 2 based on those obtained in Table A1, 0.01% K Ϫ1 was used as the temperature dependence of the molar volume. 19) Methods for estimating the surface tension of slags based on the addition of the partial molar contributions s -of the individual constituents have been reported by Appen et al,20) (A-3) where the subscripts 1, 2, 3, etc., denote the various slag constituents. Values of s i are often taken to be the surface tension of the pure component s°i.…”

Section: Discussionmentioning

confidence: 99%

“…19) The recommended values for V°for the various oxides at 1 773 K are given in Table A1. In order to calculate the values for the molar volume of CaO, SiO 2 , FeO, MgO, and TiO 2 based on those obtained in Table A1, 0.01% K Ϫ1 was used as the temperature dependence of the molar volume.…”

Section: Discussionmentioning

confidence: 99%

“…In order to calculate the values for the surface tension of CaO, SiO 2 , FeO, MgO, and TiO 2 based on those shown in Table A2, 0.15 mN m Ϫ1 K Ϫ1 was applied as the temperature dependence of the surface tension (ds/dT) of the present slag system. 19) Several models exist for the estimation of viscosities of slags based on their chemical composition. The applicability of these models has been reviewed and it was concluded that the models developed by Urbain et al 8) and Riboud et al 18) were in closer agreement with the experimentally measured viscosities than the others.…”

Section: Discussionmentioning

confidence: 99%

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Foaming Characteristics of BOF Slags.

Jung

Fruehan

2000

ISIJ International

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Slag foaming measurements were carried out for BOF type slags that exist during the first half of the blowing period in order to better understand slopping of slag. The foam index (S ) decreases with increasing FeO up to about 20 % FeO content and is almost constant for FeO from 20 to 32 % FeO. This is believed to be because above about 25 % FeO, the viscosity is nearly constant. The foam index shows a minimum value at basicity[ϭ(CaOϩMgO)/(SiO 2 ϩAl 2 O 3 )] of 1.4 at 1 713 K; it increases at higher basicities due to the precipitates such as 2CaOSiO 2 or (Fe,Mg)O which stabilizes the foam. The effect of TiO 2 and MgO on foam index was also evaluated. An empirical equation for the foam index obtained by the previous researchers was applied to the present experimental results. The foaming during the first half of the blowing in BOF process was described based on the empirical relationship and the foam height was estimated for a BOS converter as a function of decarburization rate.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Foaming Characteristics of BOF Slags.

Jung

Fruehan

2000

ISIJ International

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“…refer to the bath height and the wire injection speed respectively. The relevant physico-chemical properties of liquid slag 12,13) and liquid steel 2) are given in Table 1.…”

Section: Initial Conditionsmentioning

confidence: 99%

An Improved Model of Cored Wire Injection in Steel Melts

et al. 2004

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Mathematical models for tracking the melting of cored wire during its injection into the steel bath have been developed in the past though important aspects of the formulations have not been discussed in sufficient detail. As a result, it is difficult to use the results of these models to derive benefits for a specific steel melting shop.A general purpose mathematical model has been developed at R & D, Tata Steel, using the finite difference approach with a fully implicit scheme to simulate the process of cored wire injection taking into account the different operating practices encountered in the steel shop. Numerical simulation of this kind of problem, involving moving boundary, typically suffers from the limitation that the progressive solidification of frozen layers that takes place is not made part of the thermal balance till it attains the size of a full node and thus the heat gained or lost by this "partial node" is not accounted for till such time. An alternative numerical formulation has been developed to rectify this.Owing to the difficulty in making a direct validation, this model has been verified through a novel approach. This work suggests that the use of different wire dimensions (13-18 mm diameter and 0.4-0.6 mm casing), depending on the steel grades to be processed, is necessary in order to extract the maximum benefit.KEY WORDS: mathematical model; steelmaking; calcium treatment; cored wire; injection metallurgy; deoxidation; alloy addition.

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“…Mills and Keene, (1987) and Sundstrӧm et al (2008) provide much of the slag and matte properties data, respectively L ® Relatively low superheats of ferroalloys (FA) in DC arc and submerged-arc furnaces (SAFs) ® Higher viscosity (and Pr), but lower thermal conductivity and density of slag than metal/matte ® High thermal conductivity (k) of liquid blister Cu ® Extreme superheat ( T ) of PGM matte (Shaw et al, 2012;Hundermark et al, 2014).…”

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confidence: 99%

The tap-hole - key to furnace performance

Nelson

Hundermark

2016

J. S. Afr. Inst. Min. Metall.

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The sheer diversity of tapping configurations used on industrial pyrometallurgical operations is at first bewildering. They range from historical tilting furnaces without tapholes to modern eccentric bottom tapping (EBT) tilting and/or bottom slide-gate electric arc furnaces; to classical single tap-hole multiphase tapping (e.g. metal/matte and slag); to dedicated phase tap-holes (e.g. dedicated metal/matte-only and slag-only); to dedicated phase multiple tap-hole configurations (up to eight metal/matte-only tap-holes and six slag-only tap-holes); to more esoteric metal/matte-only siphons and slag overflow skimming, e.g. Mitsubishi Continuous Process (Matsutani, n.d.). This can be further complicated by periodic batch tapping; consecutive tapping on a given taphole; alternating tap-hole tapping practice; near-continuous slag-only tapping, with discrete batch matte/metal tapping on higher productivity, but low metal/matte fall (<20% by mass feed) Co and Ni ferroalloy and platinum group metal (PGM) matte furnaces; near-continuous tapping through batch tapping of individual tap-holes that are opened consecutively Post et al., 2003); to fully continuous tapping on coupled multi-furnace cascades (Matsutani, n.d.). This is largely a consequence of differing processing conditions (process temperature, superheat ( T), Prandtl number, Pr = C P /k, where = dynamic viscosity, C P = specific heat capacity and k = thermal conductivity, and resulting heat flux). But this can also be influenced strongly by industrial operating philosophy in terms of furnace design for campaign life longevity (i.e. greater capital expenditure for longer, say 20-30 years' life) versus furnace productivity (i.e. number of heats/campaigns to provide the greatest possible dilution of fixed costs per unit of commodity produced). And this may not even be consistent within a given commodity; all ironmakers (blast furnace (BF) campaign lifebased) supply downstream steelmakers (who use heat/campaign-based converters and/or electric arc furnaces).However, regardless of the specific taphole configuration or operating philosophy, owing to the addition of dynamic (often periodic) and more intense process conditions (exposure to higher temperatures leading to accelerated corrosion, greater turbulence, and elevated rates of mass and heat transfer) and higher concomitant thermomechanical forces (from thermal or flow shear stresses), furnace performance and longevity is intimately linked to tap-hole performance. The tap-hole -key to furnace performance by L.R. Nelson* and R.J. Hundermark † The critical importance of tap-hole design and management for furnace performance and longevity is explored through examining some of the specific matte, metal, and slag tapping requirements of non-ferrous copper blister and matte converting and smelting, ferroalloy smelting, and ironmaking systems. Process conditions and productivity requirements and their influence on tapping are reviewed for these different pyrometallurgical systems. Some critical aspects of the evolution ...

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Physical properties of BOS slags

Cited by 249 publications

References 73 publications

Foaming Characteristics of BOF Slags.

Foaming Characteristics of BOF Slags.

An Improved Model of Cored Wire Injection in Steel Melts

The tap-hole - key to furnace performance

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