• Resources Recycling
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• v.22 no.1
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• pp.11-19
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• 2013

Recovery of pure cobalt and nickel from diverse resources is important due to the increased demand for these metals. In order to get cobalt and nickel with high purity, separation of them from other metal ions is necessary. In this review, several methods to obtain pure cobalt or nickel solution, such as solvent extraction, ion exchange, precipitation were introduced and compared. For solvent extraction, the advantage and disadvantage of the separation process together with detailed process conditions were investigated.

• KSBB Journal
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• v.13 no.1
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• pp.1-5
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• 1998

A $\beta$-fructofuranosidase of garlic (Allium sativum L. ; Seosan) was purified by ammonium sulfate fractionation and gel filtration chromatography with a recovery of 8.3%. The molecular mass of the purified enzyme was estimated to be 79kDa by SDS-PAGE, which revealed two subunits of 41kDa and 38kDa. Maximum enzyme activity was observed at pH 5.0 and 40$^\circ C$ and the enzyme was stable over the pH range of 4.0-6.0 and below 50$^\circ C$. The Km value for sucrose was 15.5mM and the enzyme activity was significantly inhibited by bivalent metal ions(Hg$^2+$, Cu$^2+$, Cd$^2+$) and EDTA.

• Journal of Environmental Science International
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• v.21 no.7
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• pp.805-813
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• 2012

The removal property of Cu and Zn ions by chemical precipitation and adsorption using zeolite(Z-C1) prepared from coal fly ash(CFA) were evaluated in this study. Adsorption kinetic and equilibrium mechanisms described to analyze parameters and correlation factors with Lagergen $1^{st}$ and $2^{nd}$ order model and Langmuir and Freundlich model. Analysis of adsorption kinetics data revealed that the pseudo $2^{nd}$ order kinetics mechanism was predominant. The equilibrium data in pH 3 - 5 were able to be fitted well to a Langmuir model, by which the maximum adsorption capacities($q_{max}$) were determined at 124.9 - 140.1 mg $Cu^{2+}/g$ and 153.2 - 166.9 mg $Zn^{2+}/g$, respectively. We found that Z-C1 has a potential application as absorbents in metal ion recovery with low pH.

• Proceedings of the Korean Society of Toxicology Conference
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• 2005.05a
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• pp.136-136
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• 2005

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.137.1-137.1
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• 2016

반도체, LED, 스마트 정보통신 첨단 기기에는 고가의 비철스크랩을 많이 사용하고 있으나 폐기되고 있는 비철제품을 사용후 반드시 회수되어야 한다. 수출향상을 위해서는 적합한 분리회수 기술의 확보가 필수적이다. 금은 주로 PCB나 반도체, 전자기기, 핸드백이나 가방, 액세서리 등에 주로 사용되고 있으며, 이러한 금을 회수하면 부가가치를 달성할 수 있다. 초기에는 주로 전자제품에 사용 되었으나, 이후 디자인과 기능성부품 등으로 이용이 확대되었다. 현재 국내의 금 사용량과 수요량은 매년 급증하고는 있다. 하지만 가격불안정성과 같은 자원적 문제를 갖고 있을 뿐만 아니라 전량 수입에 의존하고 있다. 국내의 비철회수 현장에서는 W-Mo합금의 박리기술을 제공해 줄 것을 요청하고 있다. 이에 이러한 고가의 스크랩을 체계적으로 회수할 수 있는 기술정보를 제공하고자 한다.

• Ceramist
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• v.22 no.1
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• pp.96-106
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• 2019

Semiconducting carbon-based nanomaterials including single-walled carbon nanotubes(SWCNTs), multi-walled CNT(MWCNTs), graphene(GR), graphene oxide(GO), and reduced graphene oxide(RGO), are very promising sensing materials due to their large surface area, high conductivity, and ability to operate at room temperature. Despite of these advantages, the semiconducting carbon-based nanomaterials intrinsically possess crucial disadvantages compared with semiconducting metal oxide nanomaterials, such as relatively low gas response, irreversible recovery, and poor selectivity. Therefore, in this paper, we introduce a variety of strategies to overcome these disadvantages and investigate principle parameters to improve gas sensing performances.

• Microbiology and Biotechnology Letters
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• v.28 no.5
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• pp.258-263
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• 2000

A fibrinolytic enzyme was purified to homogeneity from Bacillus sp. S19 using DEAE and CM column chromatograhies, and gel filtration with a recovery yield of 13%. Its molecular mass was estimated to be 42 kDa by SDS-PAGE. The pH and temperature optima were 8.0 and $40^{\circ}C$, respectively. The enzyme was stable up to $45^{\circ}C$ and over a pH range of 6-9. The N-terminal amino acid sequence of the enzyme was determined as Alsa-Gln-Asp-Ala-Thr-Val-Asn-Ile-Ser-Ala-Glu-Arg-Gln-Val-Ile. The fibrinolytic activity was increased by $Cu^{2+}$ while it was strongly inhibited by metal ions such as $Cd^{2+}$ and $Ba^{2+}$ . In addition, the enzyme was inhibited by EDTA, but not by PMSF, suggesting that it is a metallorprotease.

• Resources Recycling
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• v.26 no.4
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• pp.71-78
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• 2017

This study investigated the recovery of metallic aluminium in the black dross generated from used beverage can recycling process with crushing mechanism such as compression and impact. The as-received Al black dross had a spherical shape, and its size was about 10~40 mm. Also, The X-ray diffraction pattern showed that the main contents of black dross are composed of halite (NaCl), sylvite (KCl), spinel ($MgAl_2O_4$) and corundum ($Al_2O_3$). A metallic aluminium recovery test was performed using jaw crusher and hammer mill having different crushing mechanism. It was analysed that Jaw crushing process can separate into metallic aluminium and non metallic constituents. However, hammer milling process shows significant difference on the separation results. It was found that jaw crushing process was effective for recovery of metallic aluminium in the black dross than that of hammer milling process.

• Resources Recycling
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• v.19 no.6
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• pp.61-69
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• 2010

S.M.C (DSME), only operating gold mine in Korea, is processing about 160 ton/day to recover gold and more than 150 ton/day of tailing is produced. Some portion of the tailings are used as a filler material after drying, but most of them are stored on the tailing dam. As a result of chemical analysis by a fire assay method, it contained Au 1.5~2.0 g/ton and 225~300 g per day of gold is getting discarded. It is urgent to develop a technology to recover and reutilize Au. In the present study, flotation tests were carried out to recovery gold for the tailings. Test results show that products with gold grade 21.31 g/ton(Au grade) and 62.73% (Au recovery) were obtained under the optimal conditions including KAX addition rate 97.2 g/ton, frother AF 65 (0.248 l/ton) and depressant sodium silicate (4 kg/ton), it's possible to recover one of the most valuable metal Au, by re-feeding to rougher flotation.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2018.05a
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• pp.53-54
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• 2018

U/RE was electrochemically recovered to LCC at $50mA/cm^2$ from LiCl-KCl salt containing $0.5wt%UCl_3$, $0.22wt%NdCl_3$, 0.15wt%$CeCl_3$ and $0.07wt%LaCl_3$. The Cd in the LCC deposit was removed during the distillation using Cd distiller. U/RE product of 107g obtained from the distiller was installed to TG and then heated to $1200^{\circ}C$ to be consolidated. Dense U/RE metal ingot was not acquired through the consolidation process because U/RE product had been partially already oxidized during the distillation process.