Abstract
The incineration reduces the volume of waste to be disposed of in landfill to 90%. But hazardous materials, such as heavy metals are leached from fly and bottom ashes and may contaminate the environment. Recently many researches about MSWI fly ash are focused on the stabilization of heavy metals and its reuse as a construction material or an adsorbent after the thermal treatment. This study is performed to recover Zn and Cu from fly ash by using D2EHPA and LIX984N (extracting agent), respectively. 84% of Zn and 99% of Cu were recovered from extracting solution, respectively. The optimal extracting condition for Zn was 20% of D2EHPA, O/A (organic/aqua) ratio with 2-30 min of reaction time. Optimal extracting condition for Cu was obtained with 10% of LIX984N at above 1.5 of pH and 30 min of reaction time. The recovery rate of Cu was not influenced by O/A ratio when it lies between 0.5 and 2.0. Finally we can recover 16,300 mg/L of Zn, or equivalent to 78% of total amount in acid-oxidation leachate, and 2,300 mg/L of Cu, or quivalent to 95% in acid-oxidation leachate by backward extraction with sulfuric acid.