This study was conducted to help manage total floating bacteria and fungi in the indoor air by studying the characteristics of total floating bacteria and fungi according to the indoor CO2 concentration of daycare centers. The sampling and analysis of samples was based on the indoor air quality process test method, and the result analysis was conducted using the SPSS statistical program to perform correlation and regression analysis. Correlation and regression results show that CO2 and total airborne bacteria showed positive relationships, but airborne mold did not show relevance. In addition, in order to identify factors affecting airborne mold, correlation analysis and regression analysis were performed regarding total airborne bacteria, PM10, PM2.5, HCHO, outdoor mold, I/O ratio, indoor temperature/ humidity, area per classroom and volume. The results showed that the factors affecting airborne mold were I/O ratio, outdoor airborne mold, and total airborne bacteria. Research results show that CO2 and total airborne bacteria can be reduced and controlled by natural ventilation, and in the case of airborne mold, mechanical forced ventilation such as hoods will be necessary due to the introduction of outdoor airborne mold. In addition, it is necessary to consider I/O ratio criteria in order to confirm effective indoor mold contamination, taking into account the effect of outdoor mold inflow.

In this study, the leaching characteristics of magnesium from mine residue by acid leaching method was studied. First, It was confirmed the effect of the particle size. The particle size was selected 80 mesh in consideration of the leaching amount and recycling rate of Mg. And after, It was compared to the leaching characteristics of magnesium by H2SO4, HCl and HNO3. Among them, leaching efficiency of H2SO4 was best. After the experiments were conducted with H2SO4. The effect of various parameters such as acid concentration, reaction temperature, and liquid/solid ratio on the leaching process were investigated. It was determined that the leaching amount of magnesium increased with reaction acid concentration, temperature, and liquid/solid ratio, and decreasing particle size. Maximum leaching amount of magnesium was obtained at the condition of particle size blow 80 mesh, temperature 80oC, 6 M H2SO4, 10/1 liquid/solid ratio, 6 h of reaction time and 180 rpm.

Converter slag is discharged as by-product from steel making process. Its chemical composition is similar to that of blast furnace slag. Therefore its recyclability is high. But actually it was not widely recycled relatively. We studied to prepare insulating brick with it for enhancing the recyclability. We discussed mixing ratio of melting slag and converter slag and also additional amounts of Al-dross and NaOH as affecting factors. According to our results, 0.195 W/mK of thermal conductivity and 3.02 MPa of compressive strength were obtained at the following condition mixing ratio 60 : 40, aluminum dross 1.5wt%, NaOH 5.6wt%. It seemed that the thermal conductivity of prepared brick was decreased with increasing amount of Al-dross and NaOH. It is satisfied with the standard of insulating fire bricks (KS L3301).

최근 IT 산업의 발달함에 따라 희유금속의 사용량과 중요성이 증가되고 있다. 따라서 도시광산 사업이 발달하게 되고, 우리나라는 2011년 6월 “희소금속의 소재화 부품화를 위한 산업생태계조성” 안을 발표 미래 성장동력과의 연계성등을 고려한 11개 희유금속을 선정하였다. 이중 마그네슘은 금속재료 중 가장 가벼운 경량소재로서 자동차 경량화 부품과 노트북, 스마트폰 등 많은 전자 제품에 사용되고 있다. 하지만 현재 마그네슘은 중국으로부터 전량 수입되고 있는 실정이다. 국내의 도시 광산으로 부터 마그네슘을 얻기 위해 광미를 사용하였다. 광미는 광물을 분리하고 남은 부산물이다. 이 부산물은 처리가 어려워 매립 처리하거나 그대로 자연에 방치하고 있어 환경오염을 유발시키고 있어 광미의 재처리가 필요하다. 다양한 재활용 방법 중 유가금속 회수는 자원 고갈에 따른 재이용 및 환경보전 측면에서 중요하며, 세계적으로 광미 재처리를 시도하고 있다. 한국에서도 광미로부터 유가금속을 회수하는 연구가 진행되어왔지만 아직 마그네슘과 관련된 연구가 없으며 더 많은 연구가 필요하다. 본 연구에서는 광미 내 존재하는 Mg를 용출하기 위해 산침출법을 적용하였다. 사용된 산성용액은 H2SO4(95%, 대정화금, 한국)이며, water bath shaking을 사용하여 용출실험에 주요인자인 입자크기, 온도, 산농도, L/S 비 실험을 수행하였다. 산침출후 침출액은 membrane filter를 사용하여 여과 후 여과액으로부터 Mg이온의 농도를 AAS(varian spectra AA-10/20, atomic adsorption spectrometer)로 분석하였다. Mg이온을 Mg(OH)2로 회수하기 위해 NaOH 용액을 사용하여 pH 10까지 조절하였다.

Geopolymer foam block was prepared and its characteristics discussed to evaluate the possibility of replacing blastfurnace slag (below BFS) with melting slag in this study. 10~20wt% of BFS was replaced with melting slag. And also10wt% of mine tailing was replaced with fly ash discharged from municipal solid waste incinerator (below MSWI). Thecompressive strength of foam block prepared was similar to that of foam block prepared without replacing BFS. Andalso it was increased by replacing 10wt% of mine tailing with MSWI fly ash. Considering these results, melting slagmay be used instead of BFS without damaging the quality of foam block.