소각비산재로부터 Cu와 Zn의 산화-산침출과 산침출의 특성 비교 연구

초록

This study investigeted the zinc and copper leaching characteristics in MSWI fly ash with the sulfuric acid and nitric acid as a leaching agent. That metals were recovered after the acidic extraction. There are many metal oxides in fly ash, such as Na2O(15.50%), K2O(12.92%), CaO(11.72%), SiO2(9.34%) and etc. Among them, main mineralogical constituents were halite(NaCl) and sylvite(KCl). Because the presence of high contents of salts as those of Na and Kin the fly ash consumes a large amount of acid during the leaching step and complicates the separation of heavy metal, washing step was carried out before the acid extraction step. Extraction step was monitored by acid concentration, L/S ratio, reaction temperature and reaction time. Through this process monitoring, the optimal condition was 10% sulfuric acid, L/S ration 1/10, 50oC of reaction temperature and 1hr of reaction time. And 20% of nitric acid was used at the same condition. But the recovery rate of Zn and Cu reached below 50% of heavy metal measured by Chris's extraction method. It was oxidized to enhance the recovery rate by 10% H2O2 after acid leaching. At oxidation-acid leaching process, the recovery rates of Zn and Cu were increased to 84%, 99% of heavy metals contained in the MSWI fly ash at this condition.

키워드