Graphite crystals in blast furnace coke

Characterization of the porous structure of cokes produced from the blends of three Polish bituminous coking coals

“…The results of TEM observations indicate that more reactive coke has less-ordered structure of pore walls than less-reactive coke of higher the Z coal content. The TEM observations of cokes produced from ternary coal blends were consistent with the results of Rouzaud et al (1998), Matsuoka et al (2005), and Gornostayev and Härkki (2007), showing that more graphitic porous cokes are less reactive to gases.…”

“…Size of MOD depends on both rank of coal and maceral composition (H and O contents) (Rouzaud and Oberlin, 1990). Recently, Gornostayev and Härkki (2007) have found graphite crystals developed as foliated intergrowths on the porous surface of a sample of blast furnace coke. The formation of graphite crystals on a surface of blast furnace coke was suggested as possible to decrease its reactivity.…”

An attempt to produce blast furnace coke from Victorian brown coal

“…It is similar in structure and form to many brittle types of foam such as are found in ceramics and glasses [3]. It is produced in large, fused, strong pieces with a much lower reactivity (Coke Reactivity Index, CRI [4] of 18-40% [5,6]) than conventional brown coal chars and is therefore suitable to be used in a blast furnace to produce iron from iron ore. Reactivity and strength are the most important parameters that characterize the quality of the coke [7,8] and its behavior in a blast furnace [1].…”

SiC and Ferro-silicides Formation in Tuyere Cokes

“…Coke minerals influence both gasification and graphitization reactions, which influence the coke fine generation and stability of burden structure in the blast furnace. 6,7) Silicon carbide (SiC) is formed through two step reactions. 8) For tuyere cokes, the reaction primarily involves generation of silicon monoxide (SiO) gas due to in-situ reduction of silica and subsequently forming SiC.…”

“…9,10) In a blast furnace, silicon also occurs with a number of iron bearing phases and often observed on coke surface. 6) These phases are grouped as iron silicides such as fersilicite (FeSi), xifengite (Fe5Si3), guepiite (Fe3Si) 11) in the order of decreasing silicon concentration.…”