Experimental Studies of Slag Flow in the Blast Furnace Hearth during Tapping Operation

I n order to clarifY the causes of the excess accumulation of mollen materials in the blast furnace hearth which gives rise to a trouble in the blast furna ce operation , such as hanging and slillping, the behaviour of .flowingout and accumulating of slag in the hearth have been studied by m~ans of model eXlleriments .The results of th~ model experiments were analyz ed as the scale-up problem based on the th ~ories of .fluiddynamics.The in.fluential fa ctors such as the porosity 0, the shape fac tor <jJ, and the mean diameter d of the coke bed in the hearth, the viscosity fJ., the density p and the superficial velocity Vo of the slag , the depth of slag layer at the beginning of its .flow-outH and the h ~arth diameter D were combined to give the dim ensionless" flow-out coefficient " F L )03, ?d l , 0 g D w hich is f oulld 10 be closely related to th e ratio of res idual slag (f , i .e. , th e ratio of the amount of residual slag at the end of tallping to that accumulated at lh ~ bgginning , in sllch a manner thal an increase in F,. causes an increase in rr ( Fig .8 ).The ranges of exlJerimental conditiollJ were selecled so as to cove r the flow conditions in the hearth in order to make it Ilossible to a/JP1y Ihe experimental results directly to the slag flo w in Ihe blas t furna ce hearlh .The amount of res idual iron is estimated to be less than one-tenth of the amounl of residual slag at the end of tap/Jillg .