Modeling the liquid levels in the blast furnace hearth

The drainage of a blast furnace hearth is analyzed on the basis of measurem ents of the instantaneous mass flow rates of tapped iron and slag, obtained from radar level measurements in the iron ladies and a pressure signal fro m the slag granulation drum. The measurements are used in a model estimatin g the levels of liquids in the blast furnace hearth, where correction terms have been introduced to prevent the level estimates from excessive drift. When applying the model on data from two Finnish blast furnaces, it was fou nd that the estimated iron level exhibited strong correlation with the elec tromotive force (emf) measured between two electrodes at the furnace shell. The results of the model are in general agreement with results reported by other investigators. The performance of the model is illustrated by some e xamples, and a procedure for considering the case of a floating dead man is proposed.