June 2016
|
World Coal
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27
Surendra Jain, The Daniels Co.,
USA, provides an overview
of sizing and classifying operations in a coal preparation plant.
T
he limit of the top size of coal and its separation into varying
sizes is governed by its use or uses. Raw coal is sized to meet
final product specifications, to remove a certain size fraction
with high ash content and to separate it into various size
fractions, as well as to be washed in the various circuits of a coal
preparation plant. Clean coal is separated into different size fractions to
comply with the specifications provided by the end user.
Vibrating screens of different kinds – sieve bends, static sieves,
classifying cyclones and/or a combination of these machines – are used to
separate coal slurry into various size fractions all the way down to 44 µm
(or 365 mesh). Dry screening of coal with acceptable efficiency is normally
limited to 9 mm or larger depending on its surface moisture. Flip-flow
screens, roller screens and screens equipped with piano-wire screen surface
SCREENING
AND
CLASSIFYING
