A general overview of the course of development of raw coal preliminary dirt removal technology and equipment

The paper presents an overview of the course of development of raw coal preliminary dirt removal technology and equipment, and an exposition from the dialectical point of view of the roles played by the said technology and equipment during the different stages of development of coal preparation technology. It is proposed to view the application of dirt removal equipment dialectically from development perspective. Analysis of the course of development of the currently widely-used movable-bed jig, shallow-bath heavy medium separator and TDS intelligent dry cleaning machine demonstrates that all the equipment have evolved through undergoing several decades of research and development work, and experienced repeated trials cyclically both in theory and practice; and the breakthrough in crucial technology in each stage helps enable the equipment to make qualitative development by leaps and bounds, facilitating, as a result, their application in more mature and expanded manner.