불소 오염토양의 기원별 오염특성을 파악하기 위한 광물학적 특성분석 및 세척효율평가

Abstract

In this study, mineralogical characteristics analysis and extraction characteristics evaluation were performed to identify the contamination characteristics by origin of fluoride-contaminated samples of natural origin by granite mica and artificial fluoride-contaminated samples by waste gypsum fluoride of making fertilizer process. In samples of natural origin, mica, quartz, feldspar, fluorite, and amphibole showed the high mineral content in the order. Among them, mica, which is expected to be the causative mineral of fluorine contamination, consisted of muscovite, biotite, and lithium mica. In artificial fluoride-contaminated samples, quartz, plagioclase, illite, gypsum, sulfur, and wollastonite showed the highest mineral content in the order. Compared to the total mica content and fluorine concentration of the natural origin contaminated sample, a proportional linear relationship(R2=0.68) was shown, and this result is estimated to be the influence of natural origin by minerals in badlock not artificial contamination. When compared with the gypsum content and fluorine concentration of the artificially contaminated samples, a proportional linear relationship(R2=0.79) was shown, and the fluoride concentration was found to exceed the standard in all samples with a gypsum content of about 20 % or more. As a result of the washing efficiency test for each mica fluoride-contaminated sample, it was confirmed that the washing efficiency was relatively low with all washing agents less than 10 %, and hydrochloric acid(HCl) had the highest washing efficiency. In addition, the optimal hydrochloric acid(HCl) concentration was confirmed to be 1 M. As a result of the washing efficiency test for each washing agent for the fluorine-contaminated sample of a fertilizer factory, sodium hydroxide(NaOH) was confirmed to have the highest washing efficiency and showed about 1.5 times higher than hydrochloric acid(HCl). In addition, the optimal concentration of sodium hydroxide(NaOH) is judged to be suitable at 0.5 M, which showed a washing efficiency of 65.6 %. Based on the results of this study, it is intended to be used as a basic data for the development of soil remediation technology considering the method of proving the cause of fluoride-contaminated soil and the characteristics of contamination by origin.