The Caking Properties Of The Vitrinite In Coking Coals And Its Coking Behavior

The coal as a whole is evaluated by the traditional index for the coal properties, which ignores the difference of the content and distribution of coal macerals. In order to accurately describe caking characteristic of coking coals, vitrinite needed to be separated from coking coal. The caking characteristic of vitrinite with different ranks and its evaluation index were studied in this work.Six coking coals with different ranks were studied, including Donghuantuo gas coal, Tangshan 1/3 coking coal, Zhongliu fat coal, Bagang fat coal, Hongsheng coking coal and Lvjiatuo coking coal. The vitrinite of coal samples was enriched using the centrifugal separation by zinc chloride density solution to obtain coal samples with different content vitrinite. The relationship of the industrial analysis index(ash, volatile matter) and the caking index(Audibert-Arnu、Giesler、G values) of coking coals with the vitrinite contents were investigated. The results showed that the ash content of coal sample decreases and the volatile of coal sample increases gradually with the increasing content of vitrinite. Audibert-Arnu, Giesler and G value increase gradually with the increase of the vitrinite content. Furthermore, G value increases linearly with the increase of the vitrinite content. The relationship of the reciprocal of the slope(1/k) and Y intercept(y0) derived from the linear equation with the coal rank( Rmax) was better fitted with a Gaussian curve, which could be used as new indexes to evaluate the activity quality of vitrinite. The pyrolysis and coking process of vitrinites was analyzed by thermogravimetric analyzer and the difference of the coking behaviors of vitrinites with different ranks were revealed. Also, the difference of the caking characteristics of vitrinites different ranks was clarified by element analysis. The research results will play important role in classifying coking coals reasonably and guiding the coal blending and coking.