Phospho-gypsum (PG) is a by-product generated from wet process of phosphoric acid production. The recycling rateof PG is only fifteen percents for the recycling uses, such as cement retardant, gypsum board, plaster, functional fertilizer.In the result of pH analysis, PG, neutralizing gypsum, soil, and dredged soil were 3.5, 7.4, 8 to 8.8, and 7.8, respectively.In case of the electric conductivity (EC), PG, neutralizing gypsum, and soil were 2,990µS/cm, 2,230µS/cm, and84~99µS/cm, respectively. In heavy metal contents of PG, As and Cd could be measured under environmentalstandards in Korean Soil Environment Conservation Act. In inorganic elements of leaching PG, Ca and Na were 629mg/L and 13 mg/L, respectively, but As, Cd, and other elements were detected under the regulated levels in Korean WasteManagement Act. Also, among inorganic elements in PG, the leaching ratio of Mg and Cd were 7.3%, 1.3% respectively.In neutralized PG, leaching ratio of Mg and Cu were 1.9%, 1.4% respectively compared with other elements. Insequential batch leaching test, the leaching concentrations of As and Cd were rapidly decreased after 2 days. F− andCa were steadily decreased until 2 days and 8 days, respectively, and no more change since then. In case of SO42−, itfell at constant rate to 1,600~1,800mg/L. As seen in Ca leaching curve relating to pH value, the leaching decreasedwith increasing pH.

본 연구에서는 고비용의 실리카흄의 대체재로서 인산부산석고와 카올린을 활용한 시멘트매트릭스의 화학적, 기계적 성질에 대하여 분석하였다. 실험을 위하여 인산부산석고는 이수석고 형태인 건조석고, 반수석고, Ⅲ형 무수석고, Ⅱ형 무수석고로 실험용시료를 제조하였으며, 900℃에서 소성된 카올린은 서냉과 급냉의 형태로 제조된 메타카올린의 형태로 제조하였다. 또한 이재료를 활용하여 혼합시멘트를 제조하였으며, 제조된 시멘트를 사용하여 실리카 흄을 혼입한 시멘트 매트릭스와 재료적 성능을 비교 평가하였다. 실험결과 급냉제조된 메타카올린이 다른 재료에 비하여 성능이 우수한 것으로 분석되었다.