An experimental technique for investigating the skulling behavior in the blast furnace hearth

The skulling behavior in the blast furnace (BF) hearth has yet to be investigated as few (if any) industrial/experimental studies with particular focus on hot metal are reported in the open literature. As a necessary first step toward a better understanding of the sophisticated behavior, an experimental technique is introduced in the present paper. The experimental apparatus, which mainly consists of a vertical tube furnace, a rotating and moveable pedestal, and a moveable water-cooled probe covered with a multi-layer structured refractory sleeve can utilize industrial coke, pig iron, and BF hearth carbon brick as raw materials. The technique is shown to be capable of producing chemical, thermal, and mechanical conditions similar to those in the real process. The feasibility and potential of the technique are demonstrated by a set of experimental runs. The results indicate that the air gap between the cooling device and the refractory lining plays a decisive role in both skull formation and lining erosion. Furthermore, the microstructure of graphite precipitated during solidification is influenced by the cooling rate, which in practice is affected by the BF hearth operating parameters. It is hoped that the current contribution will stimulate the growing research interest in this subject.