Effect of Slag Volume on the Characteristics of Post-combustion in a Test Decarburization Furnace

Abstract

Effects of flux and slag volume on the characteristics of post-combustion were studied by using a 10 t ladle type test furnace with pre-treated molten pig iron. Three kinds of flux were used : CaO, CaO-MgO and SiO₂, and amount of flux addition was varied between 3 to 15 kg/t.
Followings are brief results.
In the case that the cavity depth by O₂ jet was lower than 150 mm deep, the post-combustion ratio decreased in every flux addition as compared with no flux addition. Especially, SiO₂ flux addition caused the lowest post-combustion ratio.
From the results of heat balance, it was made clear that the heat efficiency for heating the bath decresed sharply in SiO₂ flux adding heat.
The reason is considered to be that, in SiO₂ flux adding heat, slag foaming was very high.
Some mechanisms are proposed to explain the decrease of the post-combustion ratio by the addition of SiO₂ flux.