Mineral Related CO₂and H₂O Emissions during the Production of Metallurgical Coke

Abstract

During coking processes, certain coal-associated minerals undergo various chemical changes, amongst which are dehydration, dehydroxylation, and decarbonation. In order to evaluate the character of CO 2 and H 2 O emission by a particular mineral, thermodynamic calculations for theoretical gas production were performed. Observations showed that the behavior of carbonates in respect of CO 2 emission vary substantially and, for that reason, their influence on the properties of coke differ. The amount of mineral-associated CO 2 released during the coking process is smaller than that which is produced by a carbonbased matrix. For each ton of coal, containing 1 wt% of carbonates, there will be c. 17.6-22.0 m 3 of CO 2 present at the stabilization stage of the coking process. However, the impact of a mineral-related gas phase should not be underestimated (in particular, for porosity development and cracks formation), mostly when the grain size of the minerals is quite large. The major CO 2 -related impact on coke properties can be referred to dolomite, magnesite, and calcite.

Behavior of Alkali‐Bearing Minerals in Coking and Blast Furnace Processes

“…Because of differences in crystal structure and composition, phyllosilicates and feldspars observe substantial differences in their behavior under the coking process. As we reported earlier, alkali‐bearing phyllosilicates under elevated temperatures first undergo dehydration (loss of H 2 O) and dehydroxylation (loss of OH – ) . In the presence of 1 wt% of these minerals in coking coals, the system will contain 10–110 moles of water vapor per ton of coal toward the end of the coking process (stabilization stage).…”

Effect of micro-pores on cracks formation in metallurgical coke

“…[1][2][3][4] Our earlier studies indicate that there is also porosity associated with the decomposition of inclusions of coal-associated minerals. 7 Based on that, we divided the porosity, depending on the nature and properties of the material, into carbon-(matrix-) related and mineral-related. We also reported that there also mineral-associated cracks, which appear along grain boundaries of quartz 8 and spinel 9 during coking and BF processes.…”

Catalytic Behavior of Potassium Vapor on Coke Gasification Reaction

“…Gasification is the main reason for coke quality degradation in blast furnace, moreover the recycling alkalis have been confirmed to catalyze the coke gasification in various ways . In recent years, a large number of researches on how alkali metals may influence coke behaviors in blast furnace have been conducted, as the result of the increasing trend of alkalis charged into blast furnace. Many studies indicate that the influence of K on coke is stronger than sodium (Na) …”