Coal Crushing Plant

Coal preparation

Coal preparation technology covers a wide range of processes that can be applied to improve the quality of coal to meet market requirements. These can include raw coal pre-treatment, crushing and sizing, and coal cleaning or beneficiation.

ROM coal, characteristically, is of variable size, moisture and ash content, with differing amounts and types of other contamination from the mining operation. Much of the recent development in raw coal pre-treatment has focused on ROM screening for dry fines extraction and application of improved crushing technology.

Coal crushing plant

The feed material is delivered via a ramp suitable for truck loading and dumped into a feed hopper. An Apron Feeder running at the bottom of the hopper or a scraper chain conveyor conveys the feed material at a controlled rate to the crushing system. Once the material has been crushed it is deposited on a feed conveyor below the crusher and transported to a downstream conveyor belt system for further treatment.

The design of coal crushing plant can be influenced by a number of factors including coal characteristics, market requirements, local infrastructures and regional preferences. Accordingly, there is considerable regional variation among the major coal producers in design philosophy.

In these years, ROM pre-treatment is mostly characterised by the increasing use of twin-scroll sizers for primary coal crushing and multi-angle deck (banana) screens for ROM coal pre-screening and dry fines extraction.

Coal crushers

Jaw crushers

For pre-crushing of raw coal, the use of standard jaw crushers has now declined because these can be unselective, can generate a large amount of fines and are frequently constrained by throughput capacity.

Twin-scroll sizers

During the last decade, there has been a corresponding move towards the use of twin-scroll sizers for this purpose and many of the major coal producers throughout the world now apply this technology. The twin-scroll sizer, shown in Figure 3, allows the selection of a wide range of capacity, up to 5000t/h, and a wide range of product sizes. Twin-scroll sizers also generate less fine material than crushers and the trend towards their use appears likely to continue and increase.

Rotary breakers

Rotary breakers are still widely used for ROM pre-treatment although their use has been in general decline for some time. More recently, there has been a resurgence of interest in rotary breakers in India, where they are being considered for selective breakage of coal in locations with insufficient water for extensive wet coal-cleaning processes.