DRY BENEFICIATION OF COAL—A REVIEW

Abstract

Coal continues to play a major role in the economic development of a country, especially in metallurgical industries and conventional power generation plants. For effective utilization of high ash coals, it is necessary to beneficiate them. The wet beneficiation process for coal cleaning is currently the predominant method of purification of coal in the world. However, dry beneficiation of coal has obvious advantages over wet processes. The dry processes for coal are based on the physical properties of coal and its associated mineral matters. Different types of equipment for dry beneficiation have been developed, based on the exploitation of physical properties such as density, size, shape, magnetic susceptibility, and electrical conductivity. This article presents a summary assessment of different technologies and their performance in the beneficiation process of high ash coals with particular reference to Indian thermal coals. The literature on sorting, air jigs, magnetic separation, air-dense medium fluidized bed separation, and electrostatic separation is summarized and discussed.

Keywords:

• air-dense fluidized bed separation
• coal preparation
• dry beneficiation
• electrostatic separation
• magnetic separation
• sorting

ACKNOWLEDGEMENT

The authors gratefully acknowledge the financial support of the Swedish International Development Cooperation Agency (SIDA/SAREC), Stockholm, Sweden. They thank Mr. P. S. R. Reddy and Dr. S. K. Biswal of the Regional Research Laboratory Bhubaneswar, Orissa, India, for helpful discussions.