Maceral/microlithotype partitioning through triboelectrostatic dry coal cleaning

Three eastern Kentucky and two Illinois Basin coals were tested in a bench scale triboelectrostatic separation unit. The three eastern Kentucky samples provided a rank series of petrographically comparable coals. The Illinois Basin bituminous coals were lower rank and had high vitrinite (∼ 80%) and sulfur contents in comparison to the other three coals. Triboelectrostatic beneficiation provides efficient maceral and mineral partitioning in the high volatile A and B bituminous coals tested, with vitrinite, as vitrite and vitrinite-enriched microlithotypes, reporting to the clean fractions and the inertinites, liptinites, and minerals reporting to the tails. The high volatile C bituminous Springfield coal had a lower separation efficiency than the petrographically similar, but higher rank, Herrin coal. The decreased separation efficiency in the behavior of the Springfield coal may be a response to its higher moisture content. Compared to bench-scale fuel oil agglomeration of some of the same coals, triboelectrostatic separation provides clearer partitioning of mineral matter, sulfur, and macerals.