Effect of MgO content in pellets on softening-dripping properties of burden in BF
LI Jian-peng1, LU Jian-guang2, LIU Xiao-jie1, LÜ Qing1, QIE Ya-na1
1. College of Metallurgy and Energy, North China University of Science and Technology, Tangshan 063210, Hebei, China; 2. Handan Company of Hebei Iron and Steel, Handan 056015, Hebei, China
Abstract:The appropriate MgO content in pellets can improve the metallurgical properties of slag, which is beneficial to the smelting of blast furnace. In order to explore the influence of MgO content in pellet on the performance of burden, based on the composition of final slag in on-site blast furnace (BF), the effects of different MgO contents in pellets on the initial slag and softening dripping properties of burden in BF under the condition of whole pellet smelting were studied by the high-temperature droplet furnace. It is shown that with increase of w(MgO), amount of unmineralized MgO in primary slag increases obviously, the softening finishing temperature increases, and the softening temperature zone widens, as a result, the softening performance of burden becomes worse. The melting point of initial slag increases obviously when the w(MgO) is more than 1.01%, which results in the increasing of melting characteristic temperature, therefore, the position of melting zone moves to the high temperature zone, the melting temperature zone narrows, and the permeability of melting zone is improved. With higher MgO content in the pellets, the cohesive zone temperature increases from 229 ℃ to 269 ℃, the cohesive zone thickens, as a result the permeability of burden becomes poor. Due to the increasing of w(MgO) in the primary slag with the increase of w(MgO) in the pellet, the viscosity of initial slag increases, as a result, the maximum pressure difference of burden and the characteristic values of droplet properties increase as well. Therefore, within the test conditions, with increase of w(MgO) in the pellets, the softening-dripping performance of burden in BF becomes bad and the slag-iron separation deteriorates, which is not conducive to the operation of BF.
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LI Jian-peng, LU Jian-guang, LIU Xiao-jie, LÜ Qing, QIE Ya-na. Effect of MgO content in pellets on softening-dripping properties of burden in BF[J]. China Metallurgy, 2022, 32(4): 21-26.
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