“…Meanwhile, the fine or light density particles less affected by centrifugal force, form a flowing film above the heavier seam then is conveyed by the shaking of the drum and continually washing water flow to the lower tilt inner end [ [273] , [274] , [275] ]. MGS was applied for the treatment of ultrafine coal as well as tailing pond deposits [ 276 , 277 ]. Statical optimization using response surface methodology based on Box-Behnken design (RSM-BBD) was used to analyze the effects of input parameters (i.e., drum inclination, drum rotation speed, and shaking frequency) on the output parameters (i.e., %yield, %ash, and %recovery) [ [277] , [278] , [279] ].…”