The invention discloses a wide-grain-grade double-dense-medium process for separating all coarse
coal slime. The wide-grain-grade double-dense-medium process includes that raw
coal is preliminarily sieved, manually picked and graded, then oversize products can be used as coarse grain
coal, the coarse grain coal is fed into a non-pressure tri-product dense-medium
cyclone to be separated, undersize products are concentrated and graded and then are dehydrated in an underflow manner to be used as
fine grain coal, the
fine grain coal is fed into a pressure tri-product dense-medium
cyclone to be separated, and excess flow is fed into a flotation filter-press
system, so that the coal slime can be separated; qualified suspension liquid of a
fine grain coal dense-medium separating
system is provided by coarse grain
clean coal of a coarse grain coal separating
system, lower branches of coarse grain middling coal primary-section medium removing equipment and branches of coarse grain
clean coal and coarse grain middling coal
magnetic separation concentration; dilute suspension liquid of coarse grain
gangue products and dilute suspension liquid of middling coal and
gangue products of a fine grain coal system are treated together;
magnetic separation tailings are used as
wetting water or primary spray water for grading screens. The wide-grain-grade double-dense-medium process has the advantages that the fine grain coal dense-medium system has a medium automatic generating function, all the coarse coal slime can be efficiently separated by dense media, the suspension liquid is circulated in a closed-loop manner, the separation efficiency is high, the products are flexible in structure, and the production and operation costs are low.