UTILIZATION OF COAL FOR PRODUCTION OF SILICON METALS AND ALUMINUM: EXAMPLE OF THE BLUE GEM COAL, SOUTHEASTERN KENTUCKY

The Middle Pennsylvanian Blue Gem coalbed in southeastern Kentucky is noted for having a very low ash content, in places below 1% on a whole seam basis. Further, the ash fusion temperature is very low owing to the paucity of silicates and dominance of siderite in the mineral assemblage. As such, the thin coal, with thicknesses 24 inches (61 cm) or less, has been mined extensively for use in steam generation in wet-bottom boilers.

The low-ash, low-S Blue Gem coal has also been the primary source of coal for the production of silicon metals, with much of the silicon metals industry currently based in Scandinavia. In a state-funded project, we examined the feasibility of basing at least a portion of the silicon industry closer to the coal source. We also examined the feasibility of using Blue Gem coal in the production of anode coke for the production of aluminum. A large aluminum industry already exists in the commonwealth, and the use of local coal in the process would serve to concentrate even more of the industry in Kentucky.

The Blue Gem has never been considered to be a prime coking coal owing to its low inertinite content. Our experiments, however, show that the high volatile A bituminous Blue Gem produces a solvent-refined coke with properties resembling those of the petroleum coke used in anode coke.