对国内外工业应用的干法选煤技术研究、应用情况及分选原理进行了综述;对复合式干选机的选煤机理进行了系统的分析研究:阐述了床层中颗粒物料按密度分层是系统取势能最低的必然,而力的作用使颗粒完成按密度分层。复合式干选机的特殊结构和利用颗粒重力、激振力、风力、自生介质 The research, application and sorting principle of dry process coal preparation for industrial application at home and abroad are reviewed. The coal preparation mechanism of the dry process dry machine is systematically analyzed and studied. The granular material in the bed is classified according to the density Layer is the system to take advantage of the lowest inevitable, and the role of force to complete the particle by layer of density. Compound dryers special structure and the use of particle gravity, exciting force, wind, spontaneous medium