Desulfurization of Hot Metal in an Open Ladle Stirred by an Impeller Modified by Gas Injection

Abstract

I n order to enhance the dispersion oJ desuljurization agents into hot metal, nitrogen has been injected into hot metal jointly with revolutional stirring by an impeller oJ a gate (ype. At both ends oJ impeller, nozzles are embedded and used Jor the injection oJ nitrogen into hot metal toward the opposite direction oJ the movement qf impeller. /lVater model experiments show that the gas injected I!!Jicien tly breaks up a cone-shaped agglomerate oJ demljurizing agents at the bottom oJ rotational vortexJormed around the impeller shrift and makes it disperse homogeneously into the bath. Th is suggests that the chemical ~fficiency oJ de-sl1ljitrizatioll will rise to a greater extent than that without gas i lYection. A plant scale equipmen t has been constructed to desulji,rize 60 t oJ hot metal in a ladle. H ot metal having the suljur content oJ 0 .05rJ% is reduced to 0.012% by treating it with calcium carbide oJ 3 kg (75% ill puri(y) per tOil oJ hot metal Jor 1/ min ullder the condition of 77 rjlm in revolution rate and 3 Nm 3 /min oJ nitrogen. The observed rate oJ desuljilTizatioll is reasonably inter/lreted in terms oJ the mte con/rolled by sulfur transfer ill hot metal.