자연기원 불소축적토양 정화를 위한 화학적 세척 및 부유선별 공법의 적용성 평가

Abstract

This study evaluated the feasibility of chemical washing and froth-flotation separation methods for remediating naturally occurring fluorine (F)-enriched soil due to mica weathering. The F concentration of the target soil was analyzed to be 472 ± 40.4 mg/kg. In the chemical washing experiment performed with HCl concentrations of 1, 2, and 2.5 M to remediate the soil enriched with F, only a maximum removal efficiency of up to less than 1% was achieved. As a result of sequential extraction, the residual fraction of F amounted to 99.6%, indicating that most of the F originating from weathered mica minerals was present in the soil in a chemically stable form. Thus, the chemical washing method was found to be infeasible. The froth-flotation separation was adopted by varying the collector amount, the particle size of the sample, and the pulp concentration. Consequently, a maximum removal efficiency of 62.4% (F concentration after remediation = 248 ± 29 mg/kg) was achieved, satisfying the Korean worrisome level of soil contamination (400 mg/kg). In this study, it was demonstrated that physical separation techniques, such as flotation, can be an effective measure for the active remediation (concentration reduction) of soil with accumulated F originating from F-containing mica weathering.