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Coal washingStroup, Thomas Andrew. Sheffer, Mark S. January 1912 (has links) (PDF)
Thesis (B.S.)--University of Missouri, School of Mines and Metallurgy, 1912. / The entire thesis text is included in file. Typescript. Illustrated by authors. Title from title screen of thesis/dissertation PDF file (viewed February 23, 2010) Includes bibliographical references (p. 34-37).
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Development of a separation riser with flow pulsations for small coal particlesMusser, Jordan M. H. January 2007 (has links)
Thesis (M.S.)--West Virginia University, 2007. / Title from document title page. Document formatted into pages; contains xiii, 99 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 70-72).
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Characterization and scale-up of microbubble generation in column flotation /Davis, Van Leslie, January 1990 (has links)
Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1990. / Vita. Abstract. Includes bibliographical references (leaves 121-125). Also available via the Internet.
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An investigation into the liberation characteristics of coal middlingsOliver, Edmund T. January 1989 (has links)
No description available.
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Application and evaluation of spiral separators for fine coal cleaningChe, Zhuping. January 2009 (has links)
Thesis (M.S.)--West Virginia University, 2009. / Title from document title page. Document formatted into pages; contains viii, 72 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 46-48).
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The cleaning of ultrafine coal using microbubblesTrigg, Richard Darrell January 1984 (has links)
Mechanized mining techniques that are commonly used in the coal industry produce a large amount of fine particles. These fines are extremely difficult to recover by conventional flotation methods, mainly because of the large size of the bubbles produced relative to the size of the particles. Hydrodynamic analyses have shown, however, that the use of smaller air bubbles can improve the flotation rate of these fines and, hence, the coal recovery. In the present work, a microbubble generator has been developed that produces bubbles smaller than 100 microns in diameter.
Batch flotation tests conducted on samples from five different coal seams have demonstrated that the microbubble flotation process produces improved recoveries and often cleaner products than the conventional flotation process. The higher recoveries are a result of the increased bubble-particle collision efficiencies obtained with smaller bubbles, and also the larger number of bubbles produced in the microbubble process. The improved selectivity has been explained tentatively by the longer froth residence time in the microbubble process, along with the increased bubble loading and the reduced turbulence around the microbubbles. Various techniques have proven successful in further improving the selectivity by reducing the entrainment and/or entrapment of ash in the froth.
To better understand the mechanisms of microbubble flotation, basic information regarding surface tension, contact angles, viscosity, streaming currents of microbubbles, electrophoretic mobilities of coal and mineral particles, and the stability of microbubble suspensions has been obtained using two non-ionic frothers. Microbubble flotation results obtained using each of these frothers have also been compared. / Master of Science
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An investigation of the hydrodynamics of the teetered bed separator for fine coal recovery.January 2005 (has links)
The South African coal industry produces a
large quantity of coal per annum. The rejects
from various unit operations, such as spirals,
consist of fine coal that joins the plants
tailings dam waste. As existing high quality
resources become depleted, the need to improve
recovery of this fine coal grows. This project
investigates the use of a teetered bed
separator (TBS); a hindered settling gravity
concentration device for fine coal recovery.
This device has proven successful in the
United Kingdom and in Australian collieries
for fine coal separation in the size range
between 2mm and 0.3mm. It has also been used
for decades as a classifying device for silica
sand and tin. The TBS operates in the size
range of water-only cyclones and spiral
concentrators, and could potentially be used
to separate a broader size range of coal fines
so as to offer a lower footprint device for
the fines recovery section of a plant. Spiral
concentrators cannot always be operated
efficiently at a separating specific gravity
of lower than 1.6; a TBS may also extend the
density range for separation and thus improve
recovery. The objective of this project was to
gain a full understanding of the TBS from
fundamental particle interaction and develop a
lab scale unit, which is capable of separation
to about 0.1mm at optimum conditions. This
involved the development of design parameters
based on the various distributor plates and
flow pattern modelling. The hydrodynamics of
the separator were investigated using the
Eulerian-Eulerian modelling approach of
commercial CFD package, Fluent 6.1. Seven
distributor plates of varying aperture size
and geometric arrangement were considered.
Coal and shale particles, sized between 2mm
and 0.038mm with a specific gravity (SG) range
of 1.2 to 2.0, were separated using the
laboratory scale unit. The results of both the
simulations and the laboratory tests were then
compared. The simulations revealed that Plate
3 was the best option for implementation. It
had an even upward velocity profile compared
to the other plates, with minimum wall effects
and disturbances. The upward water flow rate
(teeter water) was varied experimentally and
the composition of the teeter bed, underflow
and overflow were analysed using 1.5, 2 and
Smm cubic density tracers with an SG range of
1.2-2.0. Analysis of the partition curves of
the distributor plates revealed that Plate 3
had the lowest Ecart Probable (Ep) and cut-
point densities. The comparison of simulated
results and experimental results show that the
simulator could predict the distributor plate
design with the lowest Ep in practical tests.
The simulator could be beneficial when
optimising an industrial scale unit, by
allowing prediction of improved segregation
patterns and thus separation efficiency. / Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2005.
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Management of the mineral resource risk associated with near-density material in the beneficiation plant at Leeuwpan Coal MineBotha, Brendan William. January 1900 (has links)
Thesis (M.Sc.(Earth Science Practice & Management))--University of Pretoria, [2008]. / Abstract in English. Includes bibliographical references (leaves 85-88).
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Characterization and scale-up of microbubble generation in column flotationDavis, Van Leslie 24 March 2009 (has links)
Recent hydrodynamic studies suggest that small air bubbles can be used to improve the performance of column flotation. Tests carried out at Virginia Tech during the past several years have shown that various types of inline motionless (or static) mixers can successfully produce microbubbles for column flotation. Unfortunately, few guidelines exist for selecting the proper size and type of motionless mixer for generating microbubbles.
In the present work, the mean bubble size produced by various types of in-line motionless mixers has been experimentally determined over a wide range of operating conditions and generator geometries. Test results indicate that generator performance is described by a series of expressions derived from a dimensional analysis. These expressions demonstrate that bubble diameter is primarily determined by the generator geometry and a dimensionless term known as the Weber number.
Tests have also been conducted to determine the reduction in the performance of centrifugal pumps under air admitting conditions. A semi-empirical pump model has been utilized which allows the proper size of pump to be selected for microbubble generation. This information should prove useful for the design and operation of microbubble generation circuits on an industrial scale. / Master of Science
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A preliminary investigation of microbubble flotation of fine coalHalsey, Gregory S. January 1986 (has links)
Although froth flotation is generally recognized as the most viable means of cleaning fine coal, a loss in recovery rate and selectivity is encountered when attempting to apply the process to clean ultrafine coals. In this work, batch flotation tests were conducted on several Appalachian coals using microbubbles in a cylindro-conical flotation column. Results indicate that this technique shows improvements over the conventional technique using larger bubbles, when the coal is ultrafine. The improvement in recovery rate with the microbubbles is due to improved hydrodynamic conditions which are more conducive to bubble/particle collision, while the improvement in selectivity is due to the absence of turbulent wakes. / M.S.
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