A zeolite column system is under development to realize both a high decontamination factor and high throughput for the treatment of the spent salt generated in the pyroprocessing of the metal fuel cycle. To study the feasibility of the zeolite column system from an engineering aspect, an engineering-scale zeolite column apparatus was installed. Measurements of the superficial velocities of molten salt passing through the columns filled with granular form type-A zeolite at various driving pressures showed that the conventional relationship of the velocity and pressure loss in the components of the apparatus can be useful for the molten salt system. Then, a demonstration test to simulate the decontamination of a fission product, which was represented by cesium, was performed using a zeolite that had been pretreated in aqueous solutions to remove the sodium. Although the absorbed amount of cesium was not as high as previously reported, the concentration of cesium in the effluent salt exhibited a breakthrough curve. Therefore, some of the cesium in the salt was absorbed into the zeolite, and accordingly, the feasibility of the zeolite column system was demonstrated.