OPTIMAL MOISTURE OF SINTER MIX

Abstract

This article presents a number of works devoted to optimizing sinter mix moisture content during its preparation for sintering. Theoretical and applied indicators and parameters characterizing optimal mix moisture content are presented. The primary parameters in the initial period of sintering are the suction pressure in the vacuum chambers under the ignition hearth and in its chamber. Changes in mix moisture content in either direction from the optimal value are characterized by the surface temperature of the bed under the hearth. The final indicator for assessing the gas permeability of the sintered mix bed is the vertical process velocity for a given sinter quality. Reliable mix moisture sensors are unavailable. The updated results of previously conducted studies in the NLMK sinter plant to determine the optimal moisture content of the mix are presented. It has been established that the suction pressure in the hearth most accurately responds to changes in mix moisture content. The surface temperature of the mix bed clearly reflects the effect of insufficient or excessive mix moisture. In September 2025, experiments were repeated to reduce mix moisture content under new conditions: a slide-type throttle device was installed, the hearth was converted from blast furnace gas mixed with natural gas, and the bed height was increased from 430–460 mm to 490–495 mm. An infrared moisture meter was installed and tested downstream of the granulating drum. The results of all tests indicate that every 0.1% (absolute) deviation in mix moisture content from the baseline, considered optimal, significantly impacts the sinter machine's performance, while a deviation of 0.2% (absolute) can be considered marginal for process control. Given the limited capacity of the existing blending warehouse and the dependence of moisture meter readings on the chemical and particle size distribution of the mix, it can primarily be used to determine trends in mix moisture content. A complete solution to the problem of determining and maintaining optimal mix moisture is possible with the “Agglomerator Advisor” subsystem of the automated process control system. A set of parameters for creating this subsystem is provided.