The investigation of recovery conditions of precipitated calcium carbonate from Afşin/Elbistan Power Plant fly ashes

In this study, recovery conditions of solid calcium carbonate (CaCO3) from a solution obtained by leaching of Afsin ? Elbistan power plant fly ashes with weak hydrochloric acid (HCl) solution were investigated. During experimental study, it was conducted to find out the effects of time, gas (CO2) pressure and bulk temperature on the precipitation of Ca2+ ions as precipitated calcium carbonate (P.C.C.). Precipitation periods were changed from 1 to 6 minutes. Experiments were carried out at pressures of CO2 injected in the range of 150 ? 350 KPa. Effects of the reaction temperature were studied by changing it from 25 to 85 °C. In the end, in order to determine the properties of the product the analysis necessary were done. As a result of this work, a product containing 97.43% CaCO3 was obtained with the recovery of 93.52% at 70 °C temperature, 200 KPa pressure for 4 minutes. Key Worlds: Fly Ash, Carbonation, Calcium Carbonate, Precipitated Calcium Carbonate (P.C.C.)