Fluidized bed gasification of biomass is a promising technology. However, significant development work is required before large-scale implementation can be realized. In this work, binary mixture fluidization of silica sand and oil palm residues were accomplished to visualize the fluidization behavior of the mixture in a cold rig. The most critical characteristics for biomass gasifier operation, the minimum (Umf) and complete (U cf) fluidization velocity of the mixtures were determined. The mixtures were prepared by adding 70%^w/w, 75%^w/w, 80%^w/w, 85%^w/w, 90%^w/w and 95%^w/w of silica sand to palm kernel shell and/or palm pressed fiber. Experiments were performed in a 0.15 m diameter by 1.0 m height cylindrical column gas-solid fluidized bed system, at a constant 3 kg bed weight. The mixture was pre-mixed before being fed in to the column. The U cf/U mf ratio was found to decrease with increasing weight percentage of palm kernel shell in the mixture while the ratio increased as the weight percentage of palm pressed fibre increased in the mixture. It was also observed that segregation was reduced when the content of silica sand was increased in the binary mixture.