Анализ шлакового режима доменной плавки с использованием модельных систем поддержки принятия решений

Abstract

The article presents a balance model of the blast furnace process improved by the researchers from UrFU and PJSC "Magnitogorsk Iron and Steel Works" (MMK). It generally represents a system of deterministic dependencies characterizing the thermal, reduction, gas dynamic, blast and slag modes of blast furnace melting. The basic principle underlying the model is full-scale mathematical modeling. Indicators characterizing the properties of the final slag for implementation of normal slag mode of blast furnace melting (slag viscosity in the temperature range of 1350 - 1550 °C, as well as values of the slag viscosity gradients) were proposed. The slag viscosity gradient, along with the acceptable ranges of slag viscosity at different slag temperatures, are used in modeling the slag mode as limiting factors for the diagnosis of slag mode. Selection of the limit values of each of the ranges and the viscosity gradient is carried out by the method of expert evaluation. Structure of the model for calculating the parameters of the final slag is considered. Using a mathematical model of the blast furnace process, analysis of the slag mode of blast furnace melting was performed according to the actual indicators of their operation. It was established that desulfurizing ability of the slag is insufficiently used, as a result of which cast iron of reduced quality is smelted both in terms of content of sulfur and silicon. Change in characteristics of the slag mode, other things being equal, has a positive effect on gas permeability in the slag formation zone, reducing capacity of the gas and productivity of the blast furnace increase, as well as the consumption of coke decreases. The authors describe the results of design calculations of the MMK furnace performance indicators when changing the composition of loaded materials. Recommendations on the slag optimal basicity are given. Calculations showed that the optimal basicity of the final slag, which ensures its maximum liquid mobility, for operating conditions of blast furnaces of the combine is 1.04 - 1.05 for the CaO/SiO2ratio and 1.30 - 1.32 for the (CaO + MgO)/SiO2ratio. © 2022 National University of Science and Technology MISIS. All rights reserved.