Trans. Indian Inst. Met. Vol.57, No. 2, April 2004, pp. 103-108 TP 1878 NOMENCLATURE a Dimensionless rate constant for permanent contact reaction C t Concentration of benzoic acid in water (kg/ m 3 ) at any time, t C 0 Initial benzoic acid concentration in water (kg/ m 3 ) C ol Concentration of benzoic acid in paraffin oil (kg/m 3 ) at any time, t E Dimensionless rate constant for transitory reaction H Bath height (m) h Lance position (m) L vol Partition coefficient on volumetric basis Q Volumetric flow rate of gas (Nm 3 /s) q Oil injection rate (m 3 /s) V Volume of aqueous bath (m 3 ) V ol Volume of paraffin oil (m 3 ) V T Volume of oil at the top of the aqueous bath at the onset of experiment (m 3 ) t * Dimensionless time, defined as: t V q L t vol = * t * in Dimensionless injection period Defined in terms of t * , as follows: = t* when 0 t* t* in = t* in when t* t* in STEEL REFINING THROUGH SUBMERGED LIQUID SLAG INJECTION: EFFECT OF PARTIAL INJECTION BY A COLD MODEL STUDY Satadal Ghorai, G.G. Roy * and S.K. Roy Department of Metallurgical and Materials Engineering Indian Institute of Technology Kharagpur 721 302, India Email: ggroy@metal.iitkgp.ernet.in (Received 8 October 2003 ; in revised form 13 November 2003) ABSTRACT Injection of powder with inert carrier gas is commonly practiced in industry to decrease the impurity level of steels in a more efficient and inexpensive way. However, the advantages of submerged powder injection process are limited by the fact that powder particles can only penetrate partially into the liquid melt, while most of the particles ascend through the melt as “particles inside the bubble” without contributing much to the mass transfer process. In this regard, submerged liquid slag injection is considered as a potential area of research. Simulation of the submerged liquid slag injection in steel melt has been carried out using a cold model in the laboratory. In such a study, water, paraffin oil and benzoic acid have been used as the low temperature analogous for steel melt, slag and the transferable species, respectively. The effect of partial injection of oil on the efficacy of the mass transfer process has been investigated. The pertinent results have been analyzed by using the mathematical model of Ohguchi and Robertson after required modification. At higher volume fraction of oil, partial injection do not seem to be very effective, while at lower volume fraction, the partial injection process is proved to be quite effective in the transfer of benzoic acid from the aqueous phase to the oil phase.