The Purpose of this study is to reduce environmental problems caused by landfill of bituminous coal fly ash emitted from the power plant and to reuse it. First of all, we experimented that Al and Si elements were extracted from fly ash and investigated that extracted Al and Si elements night use a coagulant. The extraction was carried out under various conditions ; concentration of the extraction solution, calcination temperature and calcination time. As the results, it was found that the optimum conditions of the extraction of Al and Si elements from fly ash were as follows, concentration of NaOH was 5N for both of them, calcination temperature was $700^{circ}C$ and $600^{circ}C$ and calcination time was 1hr and 1.5hr, respectively The extracted solution was used as a coagulant to treat the diluted metal-plating solutions which contained Pb and Cu, respectively. As the result of treatment on the diluted Pb-plating solution with 315NTU, the removal efficiency of turbidity was more than 90%, and the removal efficiency of Pb was about 80%. As for treatment of the non-turbid diluted Cu-plating solution, the removal efficiency of Cu was about 98%.