Role of dispersed gas bubble agitation in steelmaking

Abstract

External agitation in one form or the other, is an essential part of every steelmaking process. The nature of the agitation markedly influences the steelmaking operation. In this work, two separate consequences of gas bubble agitation viz. homogenisation of the bath and removal of dissolved oxygen, both of which are important to steelmakers, were studied. While the extent of homogenisation was investigated in a cold model set up, the variation in dissolved oxygen levels in the bath was determined in laboratory as well as in operating steelmaking furnaces. It was concluded that for identical volumes of gas injected into the bath, dispersed bubble agitation results in a distinctly shorter time of mixing than agitation induced by gas introduction through a single basal tuyere. The oxygen level of an un-deoxidised bath was found to decrease sharply at first and then increase gradually following agitation and a theoretical model was developed to explain this variation. © 1989, The Iron and Steel Institute of Japan. All rights reserved.