Type of Document	Dissertation
Author	Phillips, Dennis Ivan
Author's Email Address	dphil@vt.edu
URN	etd-4198-14140
Title	Optimum Processing of 1 mm by Zero Coal
Degree	PhD
Department	Mining and Minerals Engineering
Advisory Committee	Advisor Name Title Yoon, Roe-Hoan Committee Chair Adel, Gregory T. Committee Member Luttrell, Gerald H. Committee Member Palowitch, E. R. Committee Member Wicks, Alfred L. Committee Member
Keywords	Coal processing coarse coal flotation fine coal column flotation
Date of Defense	1998-04-09
Availability	unrestricted
Abstract Coal in the finer particle size ranges (below 1 mm) has always suffered from poor cleaning efficiencies. This problem has been exacerbated in recent years with the increased amount of high ash fines due to continuous mining machines and the mining of dirtier coal seams. In the present work, it is proposed to improve overall plant efficiencies by processing coarser coal in column flotation than is now commonly treated by that method. Column flotation for coarse coal is supported by actual lab and plant test data that result in a full-scale column plant installation. The fundamentals of coarse particle detachment from bubbles are reviewed and a new simplified model is developed which better handles cubical and rectangular coal particles. Much of the lower efficiency of fine coal cleaning is due to poor size separation of the fine-sized raw coal which results in misplaced high ash fines reporting to the coarser size streams. By sending coarser material to column flotation, the finest size separation that takes place in a plant can be as coarse as 0.5 mm or greater. The proper use of wash water in a flotation column then becomes the best mechanism for desliming of the high ash clays. This work quantifies the benefits of removing the high ash fines from the plant product and increasing overall plant yield by increasing the amount of near-gravity coarse material. The resulting yield gain is greater than that obtained from only the increased fine coal recovery. Methods of column operation for improved coarse coal recovery are also evaluated.
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