Analysis of chemical-metallurgical agglomeration processes during charge sintering

Abstract

Thermally activated chemical and metallurgical processes of lumping of fine-dispersed iron ore raw material during sintering are examined in the work. The following processes are included: moisture removal, ignition of coke fines and burn-off of carbonates, taking into account burning features of coke fines, fusion of grain charge, forming of agglomeration cake, creation of overhumidification area in sintering layer owing to condensation of water vapours in washout of heat-carrying gas. Parameters of sintering kinetics are obtained experimentally, other parameters characterizing layer shrinkage of sintering charge are presented. It was established that the temperature in the sintering area has substantial effect on shrinkage. The presented temperature relationship describes experimental data with sufficient precision. The values of power exchange coefficients in the drying area are examined. The criteria equations of heat and mass exchange are presented. The mathematical model using empiric material is proposed; it describes sintering kinetics for agglomeration charge, taking into account layer shrinkage and variation of head losses in technological areas of fusion and forming of ready agglomerate, what corresponds well with the experimental data. Multi-factor relationship between chemical and metallurgical processes (from one side) and heat and mass exchange in the sintering layer of agglomeration charge (from other side) is noted. Adequacy of mathematical models allows to use them for analysis of high-efficient conditions of agglomerate fabrication. The research was conducted under financial support of the Russian Foundation of Basic Research (RFFI within the framework of the scientific project No. 18-29-24094 МК and in accordance with the State assignment, the project No. FSWF-2020-0019.