Particle mixing and segregation behavior in an Air Dense Medium Fluidized Bed with binary mixtures of solid particles were investigated for dry coal beneficiation. Magnetite mixed with coal/gangue/sand particles belonging to Geldart B/D groupwere tested individually for the bed density adjustment. The effects of operating parameters including particle density ratio, particle size ratio, mixture composition, superficial gas velocity, and fluidized bed height on the mixing and segregation pattern were examined. The results demonstrated that the segregation becomes more severe with increasing density difference of binary mixtures. An increase in particle size ratiomay also lead to partial segregation. Mixing and segregation of binary systems are almost independent of lower excess gas velocity and initial bed heightwhen it is over 15 cm. Moreover, amixing indexwas employed to evaluate themixing and segregation performance, and the criteria for good mixing to achieve the bed density adjustment were identified. (C) 2020 Elsevier B.V. All rights reserved.