Characterization and comparison of deposits in a coal-fired rotary kiln for iron ore fluxed pellets and acidic pellets productions

Compared to iron ore acidic pellet production, the deposit problem in kiln became more severe to produce iron ore fluxed pellets. This study characterized the deposit samples in a grate-kiln process for iron ore fluxed pellet production. The deposited samples were analyzed by chemical analysis, XRD, SEM-EDS, and thermodynamic software. The deposits contained mainly hematite particles embedded in bonding phases, mainly comprising silicates with different compositions. There was a significant change in the composition of bonding phases in deposits when the CaO content increased in the iron ore pellets. The bonding phases of deposits for fluxed pellets had higher CaO and Fe2O3 contents than acidic iron ore pellets. For the deposit samples from iron ore fluxed pellet production, the area of bonding phases in the phase diagram of CaO-Al2O3-SiO2-5wt%MgO moved to the higher CaO part, which had a lower liquid temperature. The change in the bonding phase caused a high proportion of formed liquid phases in the deposits, then led to severe deposit formation in the grate-kiln production plant. (C)& nbsp;2022 Elsevier B.V. All rights reserved.

Automated summary

This study investigated the deposit issues in iron ore fluxed pellet production, finding that a high proportion of liquid phases in the deposits led to severe deposit formation during the production process. The composition of bonding phases in the deposits changed significantly with an increase in CaO content in the iron ore pellets, affecting the formation of bonding phases and leading to deposit issues.