The measure which manufactures high quality recycled aggregate from the concrete block produced at the time of building demolition is taken. In this process, the waste concrete fine powder (WCFP) is produced in large quantities. However WCFP does not have the available usage. In this study, we first made the process which divides WCFP into SiO2 and CaCO3. Next, from a viewpoint of processing efficiency, we optimized acid concentration, the balance of WCFP and dissolution time.
