Abstract: The movable-bed jig used by Longquan Plant for removal of gangue from raw coal is seen to have the problems of high loss of coal in reject product and high fault rate of equipment. To deal with this situation, work is made on technical transformation of the gangue preremoval process. Based on the results of technical survey of related equipment and raw coal analysis, the plant opts to use an intelligent dry separator operating with dual-energy X-ray plus image recognition technology to replace the movable-bed jig. Field application of the separator shows that when used for treating the 200～50 mm lump coal, the gangue in the coal can be effectively removed with a removal rate of > 90% and a loss of coal in gangue of < 2%, down 9 percentage points from the figure in the case of using the movable-bed jig; and the separator works remarkably well, creating an extra revenue of about 19.4879 million yuan per year for the plant. The technical transformation work can serve as a reference for other plants facing similar problems in raw coal pretreatment process.