Metallurgical coke, also known as “Met” coke, is a carbon material manufactured by the “destructive distillation” of various blends of bituminous coal. Bituminous coal is a soft, medium grade coal that contains a high percentage of volatile components. Destructive distillation is performed in “coke batteries” which are banks of large enclosed kilns. Once the kilns are loaded, they are heated to approximately 1000 C in the absence of air. During the heat cycle the volatile components of the coal are released and the solid coal goes through a partial melt and subsequent re-solidification to a non-melting carbon. Volatile components include coal tar, ammonia, and literally dozens of other “products of decomposition”. Most volatile components are reclaimed or recycled.
The final solid is a non-melting carbon called metallurgical coke. As a result of the loss of volatile gases and of partial melting, Met coke has an open, porous morphology and may appear glassy in some specimens. As a result of the heat treatment process Met coke has a very low volatile content. However, the “ash” constituents, that were part of the original bituminous coal feedstock, remain encapsulated in the resultant coke. Met coke feedstocks are available in a wide range of sizes from fine powder to basketball-sized lumps. Typical purities range from 88-92% fixed carbon.
Commercial grades are available in sizes from 30-micrometer powders up to 20 cm lumps. Metallurgical coke is used where a high quality, tough, resilient, wearing carbon is required. Applications include but are not limited to conductive flooring, friction materials, foundry coatings, foundry carbon raiser, corrosion materials, drilling applications, reducing agents, heat-treatment, ceramic packing media, electrolytic processes, and oxygen exclusion.