제지소각재 재활용을 위한 중금속 제거 기술 연구

Heavy metal in paper sludge ash is removed by various acids, including ethylenediaminetetraacetic acid (EDTA), citric acid (CA), oxalic acid (OA), and hydrochloric acid (HCl). Among the various acids, the EDTA and OA show higher removal efficiencies for Pb, Cu, As, and Cd. In addition, the single, mixed, and sequence washing methods with EDTA and OA are compared to enhance the removal efficiencies of heavy metals. We found that the mixed washing method with EDTA and OA is the best at removing Pb, Cu, As, Hg, and Cd, achieving removal efficiencies of 49.19%, 31.29%, 28.42%, 10.00%, and 11.33%, respectively. We analyzed the elution concentrations of CN and Cl and the CaO content of the paper sludge ash to consider the possibility of recycling it. The elution concentrations of heavy metals, CN, and Cl satisfied the legal standards for paper sludge ash recycling.