Behavior of liquid passing through deadman: influence of slag/iron ratio and unburned pulverized coal

Abstract

The ability of a blast furnace hearth liquid (iron and slag) passing through deadman characterizes the activity of the blast furnace hearth. To explore the influence of various factors on the static holdup rate of liquid in the process of passing through the deadman, a physical transport model of liquid passing through the deadman was firstly established. Then, a self-designed experimental device was used to simulate the process, and the influences of slag/iron ratios (250–450\xa0kg/t) and unburned coal content (0%–9%) on the static holdup rate were studied. The experimental results indicate that with the slag/iron ratio increasing, the behavior of liquid passing through the coke packed bed gets much more difficult, and the static holdup rate increases. As the content of unburned pulverized coal (UPC) increases, the static holdup rate decreases first and then rises. This is caused by the dual effects of UPC. On the one hand, UPC can promote the carburizing reaction of unsaturated molten iron, thereby improving the fluidity of molten iron and reducing the static holdup rate. On the other hand, when the content of UPC rises to a certain level, it will be regarded as a kind of solid particle which will increase the liquid viscosity, causing an increase in the static holdup rate. Moreover, the liquid and coke will present interfacial chemical reactions when the liquid flows through the coke packed bed. And the Si-containing iron droplets at the slag–coke interface, generated by the reaction of SiO2 with C in the coke, can improve the interface wettability by reducing the interface wetting angle and increase the basicity of slag by consuming SiO2, thus improving the fluidity of the liquid and reducing the static holdup rate.