Dry Coal Beneficiation

Dry coal beneficiation processes were widely applied in Europe and the USA during the period 1930-1965 but were later abandoned, largely because separation was not accurate, available technology severely restricted feed size and throughput and moisture presented a major inhibiting factor on performance. During that period, the main processes used were pneumatic table or jig-based designs, the latter being more common. There remain a small number of units in operation, particularly in some areas of China where water is scarce, although the throughput can be considered currently insignificant.

Rotary breaker in dry coal beneficiation processes

However, increasing economic and environmental pressures to expand the use of coal preparation in some of the largest coal-producing nations, where some key production areas are in arid regions (eg in China, India and Kazakhstan), has revived interest in dry coal beneficiation processes. One current example is an evaluation of the rotary breaker as a means of de-shaling large coal in India. This process relies on selective crushing in which the tumbling action in a rotary trommel breaks the coal to the extent that it passes through the trommel screen, while the more-resistant rock remains within the trommel and passes out as oversize.

Other dry coal beneficiation processes

Other dry coal beneficiation processes that have attracted recent interest include high-intensity magnetic and electro-dynamic separation, largely because of their potential to remove fine pyrite from coal. However, these processes are expensive and, in general, separation results have been inconsistent. Nevertheless, although there are no known commercial installations in current operation, these processes remain of considerable interest in R&D circles.