A Coke Analogue for the Study of the Effects of Minerals on Coke Reactivity

Abstract

The properties of metallurgical coke are critical to the performance of the blast furnace for iron making. While extensive work has gone into understanding the relationship between the properties of coke and its behaviour in the blast furnace, the heterogeneous nature of coke makes understanding these relationships difficult. Herein we report the use of a laboratory produced coke analogue to examine the effects of minerals on the reactivity behaviour of coke in a pseudo-CRI test. The effects of a range of minerals on the reactivity of the coke analogue are demonstrated and the effects of binary combinations of silicon and iron bearing minerals are examined.

Effect of Mineral Matter on the Reactivity of Coke and its Replication in a Coke Analogue

“…Among the listed ash components listed in Table 1, Fe 2 O 3 , CaO, MgO and the alkalis increase the reactivity of cokes. 4,15) Summation of these components gives 10.9 mass% in coke A, 7.4% in coke B and 14.7% in coke C. From the simple summation of these components, it would be expected that both industrial cokes and corresponding analogues should have a reactivity sequence of coke B < coke A < coke C. However, this was not the case. Other ash components are expected to decrease the reactivity.…”

“…Some minerals are known to increase the reactivity of a coke, while others decrease the reactivity. 4,15) Reid et al 4) investigated the relative effects of single metals/minerals on the reactivity of coke analogue. Among the listed ash components listed in Table 1, Fe 2 O 3 , CaO, MgO and the alkalis increase the reactivity of cokes.…”

“…Elucidation of the effects of minerals on coke reactivity has proved difficult due to its complexity, being comprised of different forms of carbonaceous materials (macerals), mineral components and pore structure dependent on the volatile mater in the source coal (and coking conditions). 2,4,5) Coke also has significant heterogeneity in any metric(s) used to characterise its maceral grouping, mineralogy, phase dispersion, morphology and porosity. When exposed to high temperatures and reactive atmospheres, these compositional and structural features, inherent in a given coke, render isolating the specific component effects on the behaviour of a coke difficult.…”

“…The analogue is made from a number of carbonaceous materials and can be doped with minerals, including those simulating industrial coke mineralogy and porosity. The coke analogue has been used to study the effect of specific minerals and mineral combinations on coke reactivity with CO 2 at high temperatures, 4,6) to assess the reaction rate controlling mechanisms of the analogue gasification 7) and to mimic the behaviour of industrial coke on dissolution in liquid iron. [8][9][10][11] In a previous investigation on the effects of minerals on the reactivity of coke by coke analogue method, 4) single minerals were added to the coke analogue at a concentration of 0.1 mol cations per 100 g of base coke analogue, and it was found that their relative effect of the rate of reaction, as expressed in the weight change of the sample over two hours, was hematite > lime > magnetite > troilite > gypsum > pyrite > base analogue (no mineral) > Na Feldspar > K feldspar > quartz > kaolinite.…”

Impact of Zinc on Gasification Reaction and Post-Reaction Strength of Ferro-coke

“…For zinc addition, the declining rate of CSRTCM is 1.093% for every 1% increase of CRITCM, smaller than that for K2O addition (1.498%), [12] meaning the degree of damage caused by zinc is weaker than that by potassium. According to GRIGORE [13] et al and REID et al, [14] metallic iron and minerals in crystalline phases containing Fe, Ca, K and Na in the coke ash have catalytic effects on coke gasification. Zinc is usually listed in the category of transition elements and it is thus expected also having catalytic effect on ferro-coke gasification.…”