• Proceedings of the Korean Radioactive Waste Society Conference
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• 2007.11a
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• pp.279-279
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• 2007

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2008.04a
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• pp.613-615
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• 2008

• Journal of Korean Society of Environmental Engineers
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• v.27 no.6
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• pp.657-662
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• 2005

Iron sulfide(FeS) is significantly produced through both abiotic and biotic processes in natural sediments and pore waters. In this study, chromium(VI) reaction with iron sulfide at various initial concentrations and at pH values of 4 and 8 was conducted to better understand the interactions between Cr(VI) and Fe(II) species dissolved from iron sulfide in both the aqueous and solid phases. Also, the removal efficiency of iron sulfide was compared with zero valent iron and other iron bearing oxides such as ${\alpha}-Fe_2O_3$, ${\alpha}-FeOOH$ and $Fe_3O_4$. The Cr(VI) removal rate by iron sulfide was higher at pH 4 than at pH 8 because more dissolved Fe(II) existed at pH 4 than at pH 8. Chromium and iron(oxyhydroxide) could be identified on the iron sulfide surface with transmission microscopy imaging and energy dispersive spectroscopy. The removal capacity of iron sulfide was much higher than zero valent iron and other iron oxide minerals due to the synergic effect of hydrogen sulfide and ferrous iron.

• Resources Recycling
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• v.10 no.2
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• pp.20-26
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• 2001

Sulfuric acid leaching of Mn, Co and Fe from spent petrochemical catalyst was performed using hydrogen peroxide as a reducing agent. Low extraction of Mn, Co and Fe was obtained by only sulfuric acid. When hydrogen peroxide were added as a reducing agent, the high extraction of these metals could be obtained. Different from ordinary leaching, the extraction per-centages of metal components decreased with elevating leaching temperature in this process. Under the optimum condition, the extraction percentages of Mn, Co and Fe were 93.0% , 87.0% and 100% respectively.

• Resources Recycling
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• v.31 no.1
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• pp.12-20
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• 2022

The smelting reduction of spent lithium-ion batteries results in metallic alloys containing Co, Cu, Fe, Mn, Ni, and Si. A process to separate metal ions from the sulfuric acid leaching solution of these metallic alloys has been reported. In this process, ionic liquids are employed to separate Fe(III) and Cu(II). In this study, D2EHPA and Cyanex 301 were employed to replace these ionic liquids. Fe(III) and Cu(II) from the sulfate solution were sequentially extracted using 0.5 M D2EHPA with three stages of cross-current and 0.3 M Cyanex 301. The stripping of Fe(III) and Cu(II) from the loaded phases was performed using 50% (v/v) and 60% (v/v) aqua regia solutions, respectively. The mass balance results from this process indicated that the recovery and purity percentages of the metals were greater than 99%.

• Clean Technology
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• v.19 no.3
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• pp.287-294
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• 2013

The $NH_3$-selective catalytic reduction (SCR) reaction of NO with excess of oxygen were systematically investigated over Cu-zeolite and Fe-zeolite catalysts. Cu-zeolite and Fe-zeolite catatysts to adapt the SCR technology for mobile diesel engines were prepared by liquid ion exchange and incipient wetness impregnation of $NH_4$-BEA and $NH_4$-ZSM-5 zeolites. The catalysts were characterized by BET, XRD, FE-TEM (field emission transmission electron microscopy) and SEM/EDS. The SCR examinations performed under stationary conditions showed that the Cu-exchanged BEA catalyst revealed pronounced performance at low temperatures of $200{\sim}250^{\circ}C$. With respect to the Fe-zeolite catalyst, the Cu-zeolite catalyst showed a higher activity in the SCR reaction at low temperatures below $250^{\circ}C$. BEA zeolite based catalyst exhibited good activity in comparison with ZSM-5 zeolite based catalyst at low temperatures below $250^{\circ}C$.

• Resources Recycling
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• v.25 no.4
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• pp.54-59
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• 2016

EAF processed slag which contains about 20 ~ 35 weight percent FetO is poured to slag pot and cooled. If we recover Fe from molten slag by the reduction, we will improve steel yield rate and reduce slag quantity poured from the furnace. Usually, carbon is used as a reductant and slag foaming agent in the EAF process. In this experiment, after melt the metal in induction furnace and then add slag with carbon and Al dross powder as a reductant, we investigated the reduction of FetO from slag and change of Phophorus content. As the result, when we use Al dross as a reductant, recovery rate is two times more than carbon. Phosphorus pick up is less than 50ppm with reduction of EAF slag.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.3
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• pp.169-174
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• 2002

The aim of this study was to test a utilization possibility of hairy vetch as a green manure in rice cultivation. The effect of hairy vetch on yield and nitrogen uptake or rice was investigated for three years. The yield of rice increased by 7% when hairy vetch was supplied at 2~3 weeks before rice transplanting compared to that of 1 week. The proper amount of hairy vetch incorporated into soil without nitrogen fertilization was $15{\sim}20ton\;ha^{-1}$. There was a severe lodging of rice with yield reduction when hairy vetch was supplied over $25ton\;ha^{-1}$. When $20ton\;ha^{-1}$ of hairy vetch was supplied the rice yield increased by 6% due to the increase of panicle number per square meter 20%.

• Korean Journal of Microbiology
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• v.38 no.2
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• pp.133-138
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• 2002

Microbial Fe (III) reduction is important for the biogeochemical cycle in the sediment of freshwater system. Also, the Fe (III) reducing mechanism make a model of oxidizing organic compounds and reducing toxic heavy metals, such as chrome or uranium. Thirty-seven strains which have Fe (III) reducing activity were isolated from sediments in lake Soyang and Chunho reservoir. The initial concentration of Fe (II) was the highest in sediments of lake Soyang. However, the highest Fe (III) reducing activity was shown in Chunho reservoir. All isolates were tested for Fe (III) reducing activity. Strains C2 and C3, which were isolated from sediments of Chunho reservoir, showed the highest activity. These strains were tested to see if they utilize various electron donors such as glucose, yeast extract, acetate, ethanol and toluene. Significantly, glucose and yeast extract were used as electron donors. Also these strains were conformed to use humid acid and nitrate as electron accepters. The 16S rRNA sequences of strains C2 and C3 were closely related to Aeromonas hydrophila with 95% similarity.

• Resources Recycling
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• v.30 no.2
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• pp.61-67
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• 2021

Scraps are a byproduct of the machining process used for transforming titanium ingots into useful mechanical parts. Scraps take two forms, namely, bulky scraps, which are produced by cutting, and chipped scraps, which are produced by milling. Bulky scraps are comparatively easier to recycle because of their small surface area and less oxygen content; as a result, they pose only a small risk of explosion. In contrast, chipped scraps pose a higher risk of explosion, because of which, their recycling is complicated, resulting in most such scraps being discarded. With the aim of avoiding this waste, we proposed a novel process for converting chipped scraps into stable carbide materials. Methods typically applied to reduce particle size and impair the formation of solid solution type phase in the carbide materials were used to improve the mechanical properties of carbides prepared from chipped scraps. Our novel recycling process reduced carbide production costs and improved carbide quality.