Fine coal dry classification and separation

Abstract

Coal is currently cleaned with a minimum of size reduction; fine particle processing, recovery and tailings disposal are major problems; and adequate water resources are not always available. Two-thirds of China’s coal is located in arid areas. Hence, dry separation provides an alternative approach. Of the dry coal separation methods available, air dense-medium fluidized beds have been used to separate 6- to 50-mm size coal efficiently. However, excessive bubbling and back mixing of the separated solids in the air-dense media fluidized bed results in a high lower size limit of 6 mm for the feed material, which affects the preparation efficiency. Based on a previous study of air-fluidized dense-media for 6- to 50-mm coal preparation, this paper presents methods and test results on the fine coal dry classification, electrostatic beneficiation of 0- to 0.5-mm coal and magnetically stabilized fluidized beds for separating 0.5- to 6-mm coal.