Fluidization characteristics of the mixed magnetite and paigeite powder were studied by the combination approach of numerical simulation and experimental verification to optimize the design of the medium solids used in the dense gas-solid fluidized bed separator (DGSFBS). The experimental results showed that the favorable fluidization performance could be achieved with the weight proportion of paigeite powder in the mixture 25%<
a
<35%, while the relative deviation in the bed density should be Dq
0.025 g=cm3. The corresponding simulation results were obtained by selecting suitable mathematical models and parameters. It also indicated that the fluidized bed with mixed solids could provide a good fluidization performance and stable density
distribution. The laboratory-scale DGSFBS was used to conduct the separation experiments on raw coal with size range of 13–6mm and ash content of 33.43%. With the parameter a¼30%, the experiment resulted in the coal ash content being reduced from 33.43% to 11.63% with a probable error, EP of 0.07 and a recovery efficiency of 98.59%. Utilization of either magnetite or paigeite powder alone was not effective; however, fluidization performance and separation efficiency of DGSFBS improved with the utilization of mixed solids.