본 연구에서는 비소와 중금속으로 동시에 오염된 광미로부터 토양세척에 의해 비소를 제거하는 실험을 하였다. 중금속 일부도 함께 제거되었다. 최적의 세척효율을 나타내는 세척제의 종류 및 농도, 광미와 세척제의 혼합비, 세척시간 등의 조건을 도출해내었다. 비소를 제거하는데 가장 효과적인 세척제는 옥살산(72% 제거효율)과 인산(65%)이었고, 옥살산(89%)은 Cu를 포함한 중금속을 제거하는데도 매우 효과적이었다. 최적의 세척제 농도는 0.25 M이고, 세척시간은 30분이었다. 토양세척 후 발생하는 폐수를 최소화하고 비소를 효과적으로 제거할 수 있는 광미와 세척제의 적정비율은 1 : 20(질량 : 부피)이었다. 혼합세척제는 단일 세척제와 비교해서 비소제거효율에 차이가 없었으나 Cu와 Zn을 제거하는데 효과가 좋았다.
In the present paper, a study has been performed on remediating mine tailings around abandoned mine contaminated with high concentrations of arsenic and heavy metals using the technique of soil washing. Through the removal experiment of arsenic, the optimal conditions in the type and concentration of washing reagent, mixing ratio of mine tailings and washing reagent, and washing time were derived. Results showed that the most effective washing reagents to remove arsenic from mine tailings were oxalic acid(72% removal efficiency) and phosphoric acid(65%), while the oxalic acid(89%) was the most effective in removing the heavy metals containing Cu. In addition, the most economical and efficient washing concentration was 0.25 M and the most suitable washing time was 30 minutes. The optimal mixing ratio of mine tailings and washing reagent was 1 : 20(mass/vol) from the viewpoint of minimization of wastewater produced after the washing, as well as the washing effectiveness. Although the mixture of washing reagents did not help in removal of arsenic, it could lead to much elevated synergy effect on removing Cu and Zn, compared with the single reagent.
