Influence chemical composition of the coal mineral substance on the thermochemical properties blast furnace coke

Abstract

The effectiveness of coke functions in the blast furnace process largely depends on its reactivity. The reactivity of coke affects the course of blast furnace smelting, especially the profile of temperature distribution and gas flows in the furnace, and the degree of gas utilization and the specific consumption of reducing agent. It is shown that the reactivity of coke depends not only on its ash content, but also on its qualitative characteristics, that is, on the total content of oxides of various types, which affect the rate of reaction of carbon with carbon dioxide. The basic equations for calculating the ash basicity index of the batch are given, which are used to quantitatively assess the influence of ash components on the thermochemical properties of coke. It has been established that by calculating the basicity index, it is possible to provide a reasonable comparative assessment and characterize the technological value of coal concentrates and batches, as well as to quickly adjust the composition of production batches. Forecasting the quality of coke based on the properties and composition of coal batches is important for the long-term planning of supplying coke plants with coal for coking and for optimizing the composition of coal batches in the production process. The various mathematical models for predicting reactivity (CRI) and coke post-reaction strength (CSR), including using the genetic characteristics of coal, the chemical composition of their mineral substance was analyzed in the article. An equation is proposed for calculating the predictive indicators of CSR and CRI based on the basicity index of the batch ash for the raw material conditions of coke plant "ArcelorMittal Kryvyi Rih". The dependences of the CSR and CRI indicators of coke on the ash basicity index I_о of the batch and on the ash basicity index of the И_o batch were constructed, taking into account the ash content and yield of volatile substances of the batch. The use of the proposed equations will allow to optimize the composition of the production coal batch and achieve an increase in the quality of coke according to the post-reaction strength (CSR) indicator by 3-3.5%.