Mechanisms in oxidation and sintering of magnetite iron ore green pellets

Forsmo, S.P.E.; Forsmo, S.-E.; Samskog, Per-Olof; Björkman, Bo

doi:10.1016/j.powtec.2007.07.032

Cited by 148 publications

(99 citation statements)

References 6 publications

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“…At higher temperatures the oxidation rate decreases as a result of increasing dissociation pressure and severe sintering in both the oxidized haematite shell (which becomes denser) and the magnetite core (Forsmo, 2008). As fully oxidized pellets already in the grate are desired when using magnetite (Niiniskorpi, 2002), a grate of increased length and increased dwell time in a zone where the temperature is optimal for oxidation, this, in combination with oxygen injection to further improve the oxidation rate, may be an alternative in the future.…”

Section: Outlook For the Grate-kiln Processmentioning

confidence: 99%

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The grate-kiln induration machine - history, advantages, and drawbacks, and outline for the future

Stjernberg¹,

Isaksson²,

Ion³

2015

J. S. Afr. Inst. Min. Metall.

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SynopsisIron ore pellets are a preferred feedstock for ironmaking. One method used for pelletizing is the grate-kiln process, first established in 1960. During the past decade, the establishment of new grate-kiln plants has increased rapidly, especially in China, and new constructors of pellet plants have started to operate in the market. It is well known that the grate-kiln method yields a superior and more consistent pellet quality compared with the straight-grate process. However, certain issues exist with the grate-kiln plant, which are discussed here, together with proposed practical solutions.

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Section: Outlook For the Grate-kiln Processmentioning

confidence: 99%

“…Figure 1a shows iron ore pellets produced in Persberg, Sweden, during the 1970s. Today, pellets are fabricated into a more uniform shape, with sizes typically 9-15 mm (Forsmo et al, 2008). Figure 1b shows iron ore pellets produced in Kiruna, Sweden, during the 2000s.…”

Section: Introductionmentioning

confidence: 99%

The grate-kiln induration machine - history, advantages, and drawbacks, and outline for the future

Stjernberg¹,

Isaksson²,

Ion³

2015

J. S. Afr. Inst. Min. Metall.

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“…Earlier studies on mechanisms in oxidation and sintering of magnetite iron ore green pellets have shown different behaviour in the pellet core and shell. 10) A duplex pellet structure with a wellsintered core and less sintered shell may be the result. It was likely that the detachment of outer layers took place at the transition between the core and shell in the original pellet.…”

Section: Properties Of Pellets Taken Out With the Shaft Probesmentioning

confidence: 99%

Blast Furnace Pellet Textures during Reduction and Correlation to Strength

et al. 2010

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“…In the pelletizing labs, sintering degree is never measured but related properties, such as porosity and expansion during heat treatment and shrinkage during cooling [1,3,4], can be measured. However, to really understand what happens and why, one must study the micro structure.…”

Section: Introductionmentioning

confidence: 99%

Automated measurement of sintering degree in optical microscopy through image analysis of particle joins

Nellros

Thurley

Jönsson

et al. 2015

Pattern Recognition

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In general terms, sintering describes the bonding of particles into a more coherent structure, where joins form between packed particles, usually as a result of heating. Characterization of sintering is an important topic in the fields of metallurgy, steel, iron ore pellets, ceramics, and snow for understanding material properties and material strength. Characterization using image analysis has been applied in a number of these fields but is either semi-automatic, requiring human interaction in the analysis, or based on statistical sampling and stereology to characterize the sample. This paper presents a novel fully automatic image analysis algorithm to analyze and determine the degree of sintering based on analysis of the particle joins and structure. Quantitative image analysis of the sintering degree is demonstrated for samples of iron ore pellets but could be readily applied to other packed particle materials. Microscope images of polished cross-sections of iron ore pellets have been imaged in their entirety and automated analysis of hundreds of images has been performed. Joins between particles have been identified based on morphological image processing and features have been calculated based on the geometric properties and curvature of these joins. The features have been analyzed and determined to hold discriminative power based on a statistical evaluation using the Welch t-test and display properties consistent with sintering theory and results from traditional pellet diameter measurements on the heated samples.

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Mechanisms in oxidation and sintering of magnetite iron ore green pellets

Cited by 148 publications

References 6 publications

The grate-kiln induration machine - history, advantages, and drawbacks, and outline for the future

The grate-kiln induration machine - history, advantages, and drawbacks, and outline for the future

Blast Furnace Pellet Textures during Reduction and Correlation to Strength

Automated measurement of sintering degree in optical microscopy through image analysis of particle joins

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