Development of a Continuous Desiliconization Process in the Hot Metal Runner of a Blast Furnace

Abstract

An efficient continuous desiliconization process equipped with a mechanical stirrer in a hot metal runner was newly developed. The facility was installed during the revamping of No.3 blast furnace at Kobe Works, and the commercial operation started up successfully in January 2008. Before the installation of the commercial facility, the reaction behaviour was investigated under various experimental conditions for the application of a mechanical stirring method to continuous desiliconization treatment in the hot metal runner. Hot metal experiments at laboratory scale showed that the stirring intensity was an important factor for the process performance, and the mechanical stirring method was available for the improvement of reaction efficiency. As a result of plant tests, it was confirmed that a higher oxygen efficiency of desiliconization was achieved by the combination of runner arrangement and mechanical stirrer compared with the conventional injection of the desiliconizing agent. According to the reaction analysis of continuous desiliconization in the hot metal runner using the semi‐batch reaction model, it was estimated that the average slag‐metal residence time in the reaction region is improved due to an increased entrainment of foamed slag into the stirred metal bath in the mechanical stirring method, and therefore, it leads to a high desiliconization efficiency. Based on the experimental results, the equipment specifications and the runner design for this process were determined.

Effective Desiliconization Method with Swirling Flow of Hot Metal at Blast Furnace Casthouse

“…Nakasuga et al performed desiliconization with impeller stirring at a blast furnace runner. 9) However, while these methods may be effective, they have a disadvantage of requiring an installation of special, large-scale equipment.…”

Effects of Blast Furnace Main Trough Geometry on the Slag‐Metal Separation Based on Numerical Simulation

“…In a blast furnace, hot metal and molten slag are tapped out from the hearth through the taphole. They flow in the main trough (main iron runner) and then are separated by the density difference between the hot metal and the slag . The complete separation of the hot metal from the slag is expected in the skimmer region .…”

“…However, in practice, the slag may take some hot metals away when goes through the slag port. This will lead to a huge metal loss since the amount of slag is very large . Therefore, metal and slag should be separated thoroughly in the main trough.…”

Effective Desiliconization Method with Strong Mixing of Agent in Swirling Flow of Hot Metal

“…Gas injection and impeller stirring are commonly used as agitation methods, but these methods require installation of special equipment at the blast furnace casthouse. 7) One alternative is generation of a swirling flow…”