In order to confirm reduction of slaked lime by collected dust recirculated system, we tried the system at Kiryu Clean Center. Then we operated the system under 10ppm and 50ppm of HCl and SOx in exhaust gas. As a result, we confirmed from 20% to 40% reduction of slaked lime by the system. Furthermore, we could operate the system for a long term under 10ppm of HCl and SOx.