In this study, float-sink of chlorine containing and not-containing plastics in a gas-solid fluidized bed of silica sand was studied with and without joints in the air distributor and by changing the amount of objects loaded on the air distributor. The float-sink was evaluated using three parameters, i.e., recovery, purity and efficiency. The values obtained with the joints are smaller than without the joints, and decreased with increasing the amount of objects on the distributor. Because there is no airflow at the joints, the sand on the joints is not fluidized and circulating flow of the sand is generated over the area other than the joints. A 2D fluidized bed showed that air bubbles are not uniformly generated on the air distributor and the fluidization of the sand becomes intense when the objects are on the distributor. These results indicate that the circulating flow and the sudden intense fluidization disturb the expected float-sink of objects.