• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.39 no.2
• /
• pp.158-164
• /
• 1994

These experiment were conducted to evaluate the environmentally acceptable polymers, and 10 polymers were used in these study, and to investigate conductivity, germination percentage, water uptake of polymeric coating soybean seed. The conductivity of polymeric coating seed is higher than that of none coating seed and the highest conductivity was obtained with waterlock coating seed among the 10 polymer coating seed. As the soaking time was long, the conductivity was increased. The conductivity of large seed was higher than that of small seed, and that of long period storage seed was higher than that of short period storage seed. The effects of seed coating polymers on uptake water were various, and daran 8600 inhibited uptake water of low quality seed. The waterlock, captan, klucel and sacrust was rised germination percentage, and daran 8600 was declined germination percentage, and the effect of coating polymers on germination percentage of low quality seed was higher than that of high quality seed.

• Journal of Korean Society for Atmospheric Environment
• /
• v.16 no.4
• /
• pp.299-308
• /
• 2000

This study analyzed solid wastes generated from a school. The emission potential of hazardous pollutants generated from incineration of the school solid wastes (SSWs) was analyzed. Components of the SSWs were identified and the SSWs were classified into combustible and non-combustible wasts. The combustible wastes consisted of papers of 56.5^ plastics of 30.2% woods of 7.1% and fibers of 6.1% based on weight of the wastes. The moisture content and the ash content of the combustible wastes were 18~20% and 11~13% respectively. The combustible wastes of the SSWs were incinerated by using a small-scale incinerator. Fly and bottom ashes and volatile organic compounds (VOCs) were collected from the incineration. Also the metal leaching experiments on the fly and bottom ashes were performed, In analysis of metals leached from the ashes the total amounts of metals leached in the acid solution (pH=3) were much greater than those in the neutral solution (pH=5.8~6.2) For the same amounts of the fly and bottom ashes the total amounts of metals leached from the fly ashes were much greater than those from the bottom ashes. The VOCs produced from incineration of the SSWs consisted of aromatics of 42.1% aliphatic alkenes of 26.3% oxidized forms of 17.3% and aliphatic alkanes of 14.3% In addition the considerable amounts of hazardous air pollutants (e.g benzene chloro-benzene and chloro-alkanes) and compounds (e. g, aliphatic alkenes) with high potential of ozone or photochemical smog formation were identified from the incineration experiment of the SSWs.

• Analytical Science and Technology
• /
• v.15 no.1
• /
• pp.1-6
• /
• 2002

The selective removal of cesium by ammonium molybdophosphate (AMP) was studied in order to reduce an interference by high radioactivity of cesium on the determination of low radioactive elements in leachate of spent fuel. The removal of Cs, U, Ce, La, Co Ca, Na Sr and K was investigated for the leachate and the bentonite in contact with a spent fuel. More than 90% of cesium was removed by AMP and Ca, Na, Co and Sr was remained in 0.1 M $HNO_3$. However, three valence elements such as La and Ce were also removed by AMP. Though a little of potassium of the bentonite components was adsorbed on AMP, the potassium in the bentonite solution diluted to its concentration in a real sample would not affect the capacity of AMP greatly. From another experiment for the separation of strontium as a leaching indicator of spent fuel, the recovery of strontium in 8.0 M $HNO_3$ solution by using Sr-resin (Eichrom, P/N SR-B50-A) was more than 95% by eluting with 0.05 M $HNO_3$.

• Resources Recycling
• /
• v.27 no.1
• /
• pp.38-44
• /
• 2018

A large amount of Nd-Fe-B magnet scraps are generated during magnet manufacture process. In this study, selective chlorination of the rare earth elements by hydrogen chloride gas which obtained from the pyrolysis of polyvinyl chloride (PVC) was investigated. In thermogravimetric analysis, drastic weight loss was occurred at about 500 K and 710 K. At the isothermal experiments, the weight loss reaches about 30% above 673 K. XRD patterns characterized that after each experiments, ${\alpha}$-Fe, Nd oxychloride, Nd chloride, and Fe chlorides were formed, and the leaching residues remain only ${\alpha}$-Fe. The yields of Nd, Dy, and Fe for the isothermal experiment were increased with temperature and peaked at 873 K. As PVC ratio increased, the yields of Nd, Dy and Fe were also increased.

• Magazine of the Korea Concrete Institute
• /
• v.9 no.1
• /
• pp.143-151
• /
• 1997

Chemical resistance of the cement mortar containing the Thermally Activated Diaomite(TAD) and H.M.(Heavy Metals) has been studied. The H.M.. extracted from EAF(Electrica1 Arc Furnace) Dust. were saturated with diatomite. The diatomite was then thermally activated at $750{\circ}C$ for 30minutes and powdeled. The powder was mixed with a portland cement on a weight basis from 0%. 2.5%. 5.0%. 10%. 20%. The optimum mixture. after those mixtures were subjected to compressive strength(7 and 28days) and leaching bchaviour of H.M.. was tested for its experiment on Wet/Dry cycles and chemical resistance(e.q. imrncrsion in 5%(Conc.) of H2S04, CaC12 and hlgSO4. It was shown that the cement, mortar containing 10% of' P.D. gave a rise to the remarkable increase in compressive strength. The compressive strength was generally decrease beyond the addition of 10% of P.D. The maximum $496kgf/cm^2$ of 28days compressive strength was acheiveti when 10% of P.D. was added to the cement mortar.

• Journal of Wetlands Research
• /
• v.14 no.4
• /
• pp.471-478
• /
• 2012

The objective of the study is to find a way to utilize MSWI slag as filter material and to verify it. To do so, stability as filter material was tested, and used Ju-Munjin filter sand as control group to run actual filtering experiment to analyze filtering efficiency. According to result, MSWI slag is usable within designated waste acceptable standards. Also, it showed similar level of filtering capability to filter sand. Thus, MSWI slag could help to save and recycle resources if used as filtering material instead of filter sand As result of filtering test, SS and COD showed about same level of filtering capability similar to standard filter sand. MSWI slag has shown 26.96% higher with T-N, and 6.55% higher with T-P compared to standard filter sand. Also, remove efficiency comparison result with No. 40#(0.43mm) and mixed diameter showed equal or greater filtering capability.

• Korean Journal of Soil Science and Fertilizer
• /
• v.46 no.4
• /
• pp.281-287
• /
• 2013

Due to its high salt content and poor physical properties in reclaimed tidal lands, it is important to ameliorate soil physical properties to improve the efficiency of desalination. The objective of this study was to evaluate the changes of soil properties at Saemangeum reclaimed tidal saline soil with various soil amendments. Field experiment was conducted at Saemangeum reclaimed tidal land in Korea and the dominant soil series was Munpo series (coarse loamy, mixed, nonacid, Mesic, Typic, Fluvaquents). Woodchips, crushed-stone, oyster shell, coal bottom ash, and rice hull were added as soil amendments and mixed into surface soil to improve soil physical properties. There was large variability in soil hardness, but oyster shell treatment was significantly lower soil hardness at surface layer. Soil hardness was not significantly different below 15 cm depth. Infiltration rate was also significantly greater at oyster shell treatment. This may be due to the leaching of Ca ions from oyster shell and improved soil properties. However, there was no statistical significant difference of the soil bulk density, moisture content, and porosity. Improved physical properties increased desalinization rate in soil and retarded the resalinization rate when evapotranspiration rate was high. Although soil salinity was significantly decreased with oyster shell amendment, soil pH was increased that should be made up as a soil amendment. Our results indicated that oyster shell application increased infiltration rate and improved soil hardness, and thus oyster shell could be used to improve soil salinity level at Saemangeum reclaimed tidal saline soil.

• The Korean Journal of Pesticide Science
• /
• v.8 no.3
• /
• pp.175-183
• /
• 2004

The characteristics of the experimental compound EK-5439 [3-Chloro-2-[4-chloro-2-fluoro-5-(5-methyl-3-phenyl-4,5-dihydroisoxazol-5-yl-methoxy)-phenyl]-4,5,6,7-tetrahydro-2H-indazole] was investigated to characterize as a new herbicide to use in rice field. The selectivity between rice and barnyardgrass was very good when treated from 0 to 4 days after seeding under soil application. In the overflowing experiment, herbicidal efficacy of EK-5439 was stabilized 12 hrs after application. Vertical migrations in submerged paddy soil of EK-5439 and oxadiazon were equally observed below a soil depth of 1 cm under 5 cm/day leaching condition. Half-lives for herbicidal efficacy of EK-5439 and oxadiazon were 6.1, and 9.6 days, respectively, under submerged paddy condition. EK-5439 showed rapid adsorption to the soil clay, such as bentonite.

• Journal of the Mineralogical Society of Korea
• /
• v.23 no.4
• /
• pp.331-346
• /
• 2010

This study was carried out to leach valuable metals from galena using indigenous bacteria with no optimum pH conditions at room temperature. Even in these conditions, the rod-shaped indigenous bacteria, ranging from $0.4{\times}0.2{\mu}m$ to $0.5{\times}1.7{\mu}m$, were attached to the surface of the galena. For the 19 days of the bioleaching experiment, the content of Ph, Fe, Zn ions was found to be 347, 222 and 1.7 times higher than that of the control leaching agent, respectively. Numerous hexagonal column crystals were observed on the surface of galena. Those crystals may be formed from the biooxidation of galena by the indigenous bacteria. XRD analysis showed the peaks of anglesite observed in the bioleached galena. It is expected that more valuable elements can be leached out of the galena, if the bacteria is used under optimum pH and temperature conditions in future bioleaching experiments.

• Resources Recycling
• /
• v.9 no.3
• /
• pp.3-12
• /
• 2000

A Study on the cementation for the recovery of Cu, Ni and Co with Mn metallic powders in leaching solution from the manganese nodule that have removed Fe ions was studied. The results showed that the recovery efficiencies of metal ions with Mn powders increased when the temperature, pH and the concentration of chloride ions were increased in mixed solution. And the recovery efficiencies of Cu was 98% and not changed with the addition amounts of Mn powders but, in case of Co and Ni, the recovery efficiencies were increased with the addition amounts. The particle size of precipitate was about $5\mu\textrm{m}$. From the results of experiment we proposed the two-step cementation process for the recovery of Cu, Ni and Co with Mn powders.