Study on the burden distribution characteristics of a large blast furnace and the formation behaviour of primary slag near the cooling stave

With the trend towards larger blast furnaces, practical challenges such as the increasing demand for cooling system efficiency and the insufficient stability of the slag crust have become prominent, posing constraints on both safety and economic performance. In this paper, a three-dimensional model of a blast furnace with two parallel hoppers is developed based on the discrete element method. The process of burden moving from the belt to the upper part of the throat in the blast furnace and continuously falling is simulated. The relationship between burden distribution and primary slag formation behaviour in the blast furnace is examined. The results show that increasing the pellet ratios decreases the permeability of the middle part of the throat and promotes the movement of sinter and lump ore to the edge of the blast furnace, ensuring the permeability of the throat's edge. Additionally, increasing the proportion of pellets causes the primary slag formation temperature to vary non-monotonically, decreasing first and then increasing. When the basicity of the primary slag is maintained at 1.40 to 1.49, the mineral composition mainly includes merwinite, gehlenite and akermanite. The FeO content in the slag is a key factor in regulating the viscosity and ash melting temperature of the primary slag, with higher FeO content significantly reducing both. These findings provide a valuable basis for optimising blast furnace burden structure and regulating primary slag performance.