“Continuous Cooling Transformation (CCT)” Concept for Iron Ore Sintering Using In Situ Quick X-ray Diffraction and Confocal Laser Microscope

Owing to the depletion of world lump iron ore stocks, pre-treated agglomerates of fine ores are making up a growing proportion of blast-furnace feedstock (∼80%). These agglomerations, or `sinters', are generally composed of iron oxides, ferrites (most of which are silicoferrites of calcium and aluminium, SFCAs), glasses and dicalcium silicates (C2S). SFCA is the most important bonding phase in iron ore sinter, and its composition, structural type and texture greatly affect its physical properties. Despite its prevalence and importance, the mechanism of SFCA formation is not fully understood.In situpowder X-ray diffraction investigations have been conducted into the formation of SFCA, allowing the study of the mechanism of its formation and the observation of intermediate phases with respect to time and temperature. Studies have been carried out to investigate the effects of changing the substitution levels of aluminium for iron. The use of the Rietveld method for phase quantification gives an indication of the order and comparative rates of phase formation throughout the experiments.

Download Full-text

Evaluation of granule structure and strength properties of green packed beds in iron ore sintering using high-resolution X-ray tomography and uniaxial compression testing

Particuology ◽

10.1016/j.partic.2020.12.005 ◽

2021 ◽

Author(s):

Mingxi Zhou ◽

Hao Zhou

Keyword(s):

High Resolution ◽

Uniaxial Compression ◽

Iron Ore ◽

Strength Properties ◽

Compression Testing ◽

Packed Beds ◽

X Ray ◽

Iron Ore Sintering ◽

Granule Structure ◽

Ore Sintering

Download Full-text

In situ diffraction studies of iron ore sinter bonding phase formation: QPA considerations and pushing the limits of laboratory data collection

Powder Diffraction ◽

10.1017/s088571561400092x ◽

2014 ◽

Vol 29 (S1) ◽

pp. S54-S58 ◽

Cited By ~ 6

Author(s):

Nathan A. S. Webster ◽

Mark I. Pownceby ◽

Ian C. Madsen ◽

Andrew J. Studer ◽

Justin A. Kimpton

Keyword(s):

Phase Formation ◽

Iron Ore ◽

Laboratory Data ◽

Quantitative Phase Analysis ◽

Heating Rates ◽

Iron Ore Sintering ◽

Iron Ore Sinter ◽

Ore Sintering ◽

Sinter Bonding

The formation and decomposition of silico-ferrite of calcium and aluminium (SFCA) and SFCA-I iron ore sinter bonding phases have been investigated using in situ synchrotron and laboratory X-ray diffraction (XRD) and neutron diffraction (ND). An external standard approach for determining absolute phase concentrations via Rietveld refinement-based quantitative phase analysis is discussed. The complementarity of in situ XRD and ND in characterising sinter phase formation and decomposition is also shown, with the volume diffraction afforded by the neutron technique reducing errors in the quantification of magnetite above ~1200 °C. Finally, by collecting 6 s laboratory XRD datasets and using a heating rate of 175 °C min−1, phase formation and decomposition have been monitored under heating rates more closely approximating those encountered in industrial iron ore sintering.

Download Full-text

Thermodynamic Modelling of Iron Ore Sintering Reactions

Minerals ◽

10.3390/min9060361 ◽

2019 ◽

Vol 9 (6) ◽

pp. 361 ◽

Cited By ~ 6

Author(s):

Chunlin Chen ◽

Liming Lu ◽

Kexin Jiao

Keyword(s):

Oxygen Partial Pressure ◽

Partial Pressure ◽

Iron Ore ◽

Raw Material ◽

Melt Viscosity ◽

Iron Ore Sintering ◽

Mineral Phases ◽

Ore Sintering ◽

Multi Phase

Silico-ferrite of calcium and aluminum (SFCA) is one of the most commonly-produced phases in fluxed iron-ore sintering, and has long been regarded as an important bonding phase in industrial sinters. It is thus considered to have a significant effect on sinter quality. In this study, a solid solution model and database has been developed for the SFCA phase, and has been incorporated into the thermodynamic software, Multi-Phase Equilibrium (MPE). MPE calculations were compared with the in situ X-ray powder diffraction (XRD) observations of the formation of SFCA phase during sintering. The effects of the raw material composition, temperature and the oxygen partial pressure on the formation of mineral phases in the sinter, as well as the viscosity of the melt formed during sintering under equilibrium conditions, were modelled using MPE. The results show that the formation of SFCA phase can be promoted by increasing oxygen partial pressure and basicity of the raw material. Increases of Al2O3 and MgO content have no significant effect on the SFCA formation under equilibrium condition. The increase of oxygen partial pressure (10−3 atm or above) and basicity also leads to a decrease in melt viscosity, which enhances the fluidity of the melt, and hence, the assimilation of the sinter. However, increases of Al2O3 and MgO result in the increase of melt viscosity.

Download Full-text