Mineral matter crystallization and crack formation in tuyere coke

Minerals and iron-making reactions in blast furnaces

“…25 illustrates crystallization of an iron-rich olivine whose composition is approximately represented by (Fe 0.7 Mg 0.3 ) 2 SiO 4 , which is intermediate between the two-end members of fayalite (Fe 2 SiO 4 ) and forsterite (Mg 2 SiO 4 ). Crystallization could cause stress in the carbon matrix due to volumetric changes, e.g., spinel formation was attributed for the crack initiation in the tuyere coke of an operating blast furnace [92].…”

“…Addition of CaO decreased the dissolution rate, but addition of iron oxide increased the coke dissolution rates [113]. The mode of additive introduction seems to be responsible for the different behavior: in the one experiment CaO was added to the coal [115]; in the other, it was mixed with the coke [113] Recently, iron oxide and silica reduction reactions at the interface were also shown to play a significant role in controlling the dissolution rate [92].Thus coke ash not only forms a physical barrier but also participates in chemical reactions at the coke/iron interface. High ash yield cokes tended to have lower dissolution rates than low-ash-yield cokes (Fig.…”

Mineral Related CO2and H2O Emissions during the Production of Metallurgical Coke

“…The influence of coal-inherited minerals to the properties of metallurgical coke has been reported in a number of publications (e.g., [1][2][3][4][5][6][7][8][9] and references therein). Amongst those are summaries on various minerals and their behavior in general [1][2][3][6][7][8] and, also, detailed descriptions of transformations of particular mineral species in coking and blast furnace (BF) processes as, for example, quartz, [4] and pyrite.…”

“…Amongst those are summaries on various minerals and their behavior in general [1][2][3][6][7][8] and, also, detailed descriptions of transformations of particular mineral species in coking and blast furnace (BF) processes as, for example, quartz, [4] and pyrite. [5] During coking processes, the minerals undergo various physical and chemical changes, which include desulfurization, decarbonation, dehydration, dehydroxylation, polymorph transformations, melting with the formation of an alkali and silica-rich liquid, and transformation to another crystalline phase.…”

“…. intensification of its fracture process on the way from the middle of the stack to blast-furnace hearth due to the chemical effect of CO 2 and water vapor.'' [11] Furthermore, experiments with a Blast Furnace Gas Phase Simulator, [12,13] have shown that various H 2 O concentrations affect the reactivity of certain coke textures.…”