Hot metal flow characteristics and its contribution to hearth erosion in the early stage of blast furnace campaign

Abstract

Hot metal circulation is one of the most important factors for hearth erosion. In this article, both the production conditions reflected by production parameters and the actual erosion state are considered. A series of cases are set up to analyze the hot metal flow characteristics and its contribution to hearth erosion. The main results are as follow: (1) There are two asymmetric high-speed bands existed on both side of the taphole, which is caused by the inner shape of blast furnace hearth and will cause the erosion of blast furnace hearth. (2) The velocity inside the deadman has an obvious decrease from top to middle part and then keeps almost stable, especially at the edge of deadman. It is caused by the inhibition effect of molten iron flow around deadman, and may result in a slower update rate of deadman in the lower part as well as an increase of carbon unsaturation in the molten iron. (3) The velocity of line 4–5# around the bottom increases with the increasing of daily output, and decreases with the increasing of the depth of salamander. Therefore, in the early stage of the blast furnace campaign, a production process with high utilization factor will increase hearth erosion. (4) The inner shape of hearth and the distance between sidewall and deadman are the main factors affecting the flow rate of molten iron.