제강슬래그의 매체접촉형 재활용에 따른 중금속 용출특성 및물벼룩 생태독성 평가

초록

Most of the slags generated from steel-making industry in Korea are recycled into media-contact aggregates such as filland cover materials. For their use as media-contact aggregates, the slags must meet not only the waste quality criteria, butalso the Daphnia magna acute toxicity test criteria. In this study, Korean Leaching Test ES 06150.e (Korea), JapaneseLeaching Test JIS K 0058-1(Japan), Detuch Leaching Test DIN 19529 (Germany), Toxicity Characteristic LeachingProcedure (USA) were conducted for batch leaching test of slags from 6 Korean steel-making companies. In addition,Korean Standard up-flow percolation test (ES 06151.1) mimicking field conditions was conducted to assess the impact ofthe slag leachate on the surrounding environment indirectly. Heavy metals such as Cr6+ and Zn2+ were detected from bothextractant and leachate samples, but all of them did not exceed waste quality criteria of each country. However, Daphniamagna acute toxicity tests using the leachate samples from up-flow percolation test with slag alone and slag/natural soilconditions exceeded ecotoxicity standard (TU=2) due to their high pH (11.3-12.5). After neutralizing the pH of the slagleachate to 6.5~8.5, the Daphnia magna mortality and immobilization were reduced to satisfy ecotoxicity standard. As thereducing pH of slag leachate would be extremely difficult, appropriate recycling management considering thephysicochemical characteristics of he slags should be stuided further.

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