Distribution of Se and Cd during coal coking

The content of trace elements such as Cd, Se in coal and coking products including solid-phase product (coke) and liquid-phase products (tar and ammonia) were determined. The contents of trace elements in coals with different ranks were compared and the distribution of Cd, Se during coal coking was discussed. It is shown that the content of Cd decreases with increasing coal rank. The content of Se in fat-coal is lower than that in gas coal, however, its content in coking coal is close to that in lean coal. Coking in a simulated temperature of 1000℃, 48% of Cd and 45% of Se remain in the coke; 7% of Cd and 2% of Se are transferred into the ammonia; 15% of Cd and 12% of Se are partitioned into the tar. Through the mass balance it is found that 30% of the Cd and 41% of the Se could potentially exist in gas phase.