Low rank coal beneficiation
Low rank coal beneficiation is sub-divided between (1) ash and pyritic sulfur specific gravity beneficiation, and (2) inherent moisture reduction. With the exception of some Bituminous “C” coals in Illinois (and Alberta) there is no commercial scale specific gravity beneficiation of low rank coals in North America. There is some pilot scale evaluation of the dry beneficiation processes being marketed by Almineral and the Tangshan Shenzhou Machinery Company (represented by Eriez). In most cases these processes are being evaluated as a de-shaling / destoning operation.
There are some low rank thermal drying processes being used and/or evaluated in North America including:
- The ongoing operation of the nine 52 year old Perry Dryers processing lignite at the Alcoa- Sandow Refinery in Texas (scheduled to be shutdown in 2007).
- The utilization of waste steam drying at a “mine-mouth” lignite operation in North Dakota
- The 2004 startup of a vibrating, fluidized bed thermal coal pre-dryer on lignite being fed to a calciner at the Luscar-Bienfait Mine in Saskatchewan, Canada (furnished by Carrier Corp. , Louisville, KY).
- The startup of the KFx saturated steam drying process on sub-bituminous coal in Gillette, Wyoming (an update of the Fleissner Process).
- The design and construction of a combined gas recirculation flash dryer / binderless briquetting facility in Indonesia (initially developed by K. R. Komarek of Chicago, IL and TraDet, Inc. of Wheeling, WV).