• Resources Recycling
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• v.29 no.5
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• pp.73-80
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• 2020

In order to develop a process for the recovery of valuable metals from spent LiBs, solvent extraction experiments were performed to separate Cu(II) and/or Co(II) from synthetic hydrochloric acid solutions containing Li(I), Mn(II), and Ni(II). Commercial amines (Alamine 336 and Aliquat 336) were employed and the extraction behavior of the metals was investigated as a function of the concentration of HCl and extractants. The results indicate that HCl concentration affected remarkably the extraction efficiency of the metals. Only Cu(II) was selectively at 1 M HCl concentration, while both Co(II) and Cu(II) was extracted by the amines when HCl concentration was higher than 5 M, leaving the other metal ions in the raffinate. Therefore, it was possible to selectively extract either Cu(II) or Co(II)/Cu(II) by adjusting the HCl concentration.

• Korean Journal of Materials Research
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• v.29 no.3
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• pp.150-154
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• 2019

This study investigates the effect of MnO2 and CuO as acceptor additives on the microstructure and piezoelectric properties of $0.96(K_{0.5}Na_{0.5})_{0.95}Li_{0.05}Nb_{0.93}Sb_{0.07}O_3-0.04BaZrO_3$, which has a rhombohedral-tetragonal phase boundary composition. $MnO_2$ and CuO-added $0.96(K_{0.5}Na_{0.5})_{0.95}Li_{0.05}Nb_{0.93}Sb_{0.07}O_3-0.04BaZrO_3$ ceramics sintered at a relatively low temperature of $1020^{\circ}C$ show a pure perovskite phase with no secondary phase. As the addition of $MnO_2$ and CuO increases, the sintered density and grain size of the resulting ceramics increases. Due to the difference in the amount of oxygen vacancies produced by B-site substitution, Cu ion doping is more effective for uniform grain growth than Mn ion doping. The formation of oxygen vacancies due to B-site substitution of Cu or Mn ions results in a hardening effect via ferroelectric domain pinning, leading to a reduction in the piezoelectric charge coefficient and improvement of the mechanical quality factor. For the same amount of additive, the addition of CuO is more advantageous for obtaining a high mechanical quality factor than the addition of $MnO_2$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.3 no.2
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• pp.156-159
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• 2002

Ion exchange is the most reliable process to remove the ionic impurities and the economic operation. ion exchange is widely used in water and wastewater treatment, especially softening and demineralization. ion selectivity depends on the hydrated radius, charge of ions and concentration. The objective of this study was to determine the selectivity order of cations with equilibrium and column ion exchanges and to investigate the effect of the background anion on selectivity. Cation selectivity increases with decreasing concentration and increasing charge ( $H^+$ < $K^+$ << $Cu^{2+}$ < $Co^{2+}$ < TEX>$Ca^{2+}$ << $Ce^{3+}$)in equilibrium and column cation adsorptions.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.179-179
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• 2011

관통전극(TSV, Trough Silicon Via) 기술은 전자부품의 소형화, 고성능화, 생산성 향상을 이룰 수 있는 기술이다. Cu는 현재 배선 기술에 적용되고 있고 전기적 저항이 낮아서 TSV filling 재료로 사용된다. 하지만 확산 방지막에 의해 완벽히 감싸지지 않는다면, Cu+은 빠르게 절연막을 통과하여 Si 웨이퍼로 확산된다. 이런 현상은 절연막의 누설과 소자의 오동작 등의 신뢰성 문제를 일으킬 수 있다. 현재 TSV의 제조와 열 및 기계적 응력에 관한 연구는 활발히 진행되고 있으나 Biased-Thermal Stress(BTS) 조건하의 Cu 확산에 관한 연구는 활발하지 않는 것이 실정이다. 이를 위해 본 연구에서는 TSV용 Cu 확산 방지막 Ti에 대해 Cu+의 drift 억제 특성을 조사하였다. 실험을 위해 Cu/확산 방지막/Thermal oxide/n-type Si의 평판 구조를 제작하였고 확산 방지막의 두께에 따른 영향을 조사하기 위해 Ti의 두께를 10 nm에서 100 nm까지 변화하였으며 기존 Cu 배선 공정에서 사용되는 확산 방지막 Ta와 비교하였다. 그리고 Cu+의 drift 측정을 위해 Biased-Thermal Stress 조건(Thermal stress: $275^{\circ}C$, Bias stress: +2MV/cm)에서 Capacitance 및 Timedependent dielectric breakdown(TDDB)를 측정하였다. 그 결과 Time-To Failure(TTF)를 이용하여 Cu+의 drift를 측정할 수 있었으며, 확산 방지막의 두께가 증가할수록 TTF가 증가하였고 물질에 따라 TTF가 변화하였다. 따라서 평판 구조를 이용한 본 실험의 Cu+의 drift 측정 방법은 향후 TSV 구조에서도 적용 가능한 방법으로 생각된다.

• Electrical & Electronic Materials
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• v.1 no.2
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• pp.126-135
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• 1988

Acrylonitrile-Acrylic acid 공중합체와 이를 amidation시킬 공중합체에 구리착물을 형성시켜 IR spectrum분석, 점도측정, 전자현미경관찰, 열분석, 전기전도성등을 검토하였다. AN-AA 공중합체-Cu(II)와 아미드화 AN-AA 공중합체-Cu(II)착물은 pH9의 범위에서 가장 안정한 값을 가지며 착물이 형성되거나 Cu$_{x}$S가 도입된 공중합체는 그 구조가 ompact해짐을 알 수 있었다. 공중합체에 Cu(II)착물이 형성되면 열안정성이 감소되며 Cu(II)착물은 아세톤 용액에서 요오드로 dope 될 때 저항값이 $10^{5}$-$10^{6}$.OMEGA..cm를 나타냈다. 저항값은 CuCl$_{2}$와 I$_{2}$의 양에 영향을 받으며 20wt% 이상의 CuCl$_{2}$와 1.0wt% I$_{2}$로 처리하였을 때 반도체영역의 저항값을 보였다. 또 Cu$_{x}$S를 도입할 경우 CuSO$_{4}$의 농도가 30g/l로, 3시간 반응시켰을 때 가장 만족스러운 전도도값을 나타냈다. 공중합체-Cu(II)보다 구리이온을 도입한 Cu$_{x}$S공중합체의 전도도값이 $10^{4}$정도로서 공중합체-Cu(II)보다 높은 전도성을 나타냈다.다.

• Journal of the Korean Chemical Society
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• v.35 no.6
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• pp.645-652
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• 1991

The stability constants$(K_f)$ of the complexes of some transition and post-transition metal ions (Co(Ⅱ), Ni(Ⅱ), Cu(Ⅱ), Zn(Ⅱ), Cd(Ⅱ), Pb(Ⅱ), Hg(Ⅱ)) with $N_2O_3$-donor macrocyclic ligand, 1,15-diaza-3,4 : 12,13-dibenzo-5,8,11-trioxacyclooctadecane ($NtnOdienH_4$), have been determined by potentiometry in aqueous solution at $25^{\circ}C$. Log $K_f$ values of the complexes were : Co(Ⅱ): 3.83, Ni(Ⅱ) : 4.56, Cu(Ⅱ) : 7.74, Zn(Ⅱ) : 4.98, Cd(Ⅱ) : 3.91, Pb(Ⅱ) : 6.65, and Hg(Ⅱ) : 14.87. The order of stabilities of transition metal complexes was the same as the natural order of stability proposed by Williams-Irving. In post-transition metal complexes, the order of stabilities was Cd(Ⅱ) < Pb(Ⅱ) < Hg(Ⅱ), and the covalent character in metal ion-donor atoms bonds appeared a dominant factor in the stability. In methanol solution, each metal ion forms 1 : 1 complex, while Ni(Ⅱ) ion forms both 1 : 1 and 1 : 2 complexes. It was confirmed by $^1H-$ and $^{13}C-$NMR spectral study that the nitrogen atoms in the ligand were major contributors for the complexation of post-transition metal ions with the ligand. It was shown, by elementry analysis, electrical conductivity and magnetic susceptibility measurements, and spectral analysis, that solid Cu(Ⅱ)-and Zn(Ⅱ)-complexes have a distorted octahedral and a tetrahedral structure, respectively.

• Applied Chemistry for Engineering
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• v.10 no.1
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• pp.166-172
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• 1999

Fixed-bed adsorption of metal ions on chitosan bead was studied to remove heavy metal ions in waste water. Chitin was extracted from carb shell and chitosan was prepared by deacetylation of the chitin. The chitosan in bead was used as an adsorbent for heavy metal ions. Freundlich and Langmuir isotherm was determined from the experimental results of equilibrium adsorption for individual metal ion ($Cu^{2+}$, $Co^{2+}$, $Ni^{2+}$) on chitosan bead. Adsorption strength of metal ions decreased in the order of $Cu^{2+}$>$Co^{2+}$>$Ni^{2+}$ ion. Breakthrough curves of single and multicomponent adsorption for metal ions were obtained from the experimental results of fixed-bed adsorption. The breakthrough curves were analyzed by simulation with fixed-bed adsorption equation based on LDFA (linear driving force approximation) adopted LAS (ideal adsorbed solution) theory which can predict multi-component adsorption isotherm from individual adsorption isotherm. The behavior of fixed bed adsorption for single and multi-component system could be nicely simulated by the equation.

• Journal of the Mineralogical Society of Korea
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• v.27 no.4
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• pp.293-299
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• 2014

The bentonite, a buffer material, is essential for the deep geological disposal of HLW (high-level radioactive waste), and it is important to know its characteristic long-term evolution in the underground environment. With an assumption that the concentration of aqueous copper ions will increase if copper-coated materials on a metal canister are corroded, we examined some characteristic ion-exchanges and cation release phenomena occurring in the bentonite clay (montmorillonite) interacted with aqueous Cu cations. During the interaction between dissolved copper and bentonite, Na rather than Ca cations in the expandable clay were preferentially replaced by Cu ions in the experiment. In addition, the Cu-exchanged montmorillonite was characterized by an asymmetric X-ray diffracted pattern with relatively collapsed interlayers compared to the raw sample. These results indicate that the gradual change of the original bentonite property may occur in a underground disposal condition. We are going to further study the characteristic chemical and mineralogical changes of the bentonite buffer to be used for the disposal site by conducting additional experiments.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.101-101
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• 2018

Quantitative measurement of chloride ion concentration has an important role in various fields of electrochemistry, medical science, biology, metallurgy, architecture, etc. Among them, its importance of architecture is ever-growing due to unexpected degradations of building structure. These situations are caused by corrosion of reinforced concrete (RC) structure of buildings. And chloride ions are the most powerful factors of RC structure corrosion. Therefore, precise inspection of chloride ion concentration must be required to increase the accuracy of durability monitoring. Multi-walled Carbon nanotubes (MWCNTs) have high chemical resistivity, large surface area and superior electrical property. Thus, it is suitable for the channels of electrical signals made by the sensor. Silver nanoparticles were added to giving the sensing property. CuBTC, one of the metal organic frameworks (MOFs), was employed as a material to improve the sensing property because of its hydrophilicity and high surface area to volume ratio. In this study, sensing element was synthesized by various chemical reaction procedures. At first, MWCNTs were functionalized with a mixture of sulfuric acid and nitric acid because of enhancement of solubility in solution and surface activation. And functionalized MWCNTs, silver nanoparticles, and CuBTC were synthesized on PTFE membrane, one by one. Electroless deposition process was performed to deposit the silver nanoparticles. CuBTC was produced by room temperature synthesis. Surface morphology and composition analysis were characterized by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), respectively. X-ray photoelectron spectroscopy (XPS) was also performed to confirm the existence of sensing materials. The electrical properties of sensor were measured by semiconductor analyzer. The chloride ion sensing characteristics were confirmed with the variation of the resistance at 1 V.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.6
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• pp.100-107
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• 2021

As a significant technology in the smartization era promoted by the Fourth Industrial Revolution, the secondary battery industry has recently attracted significant attention. The demand for lithium-ion batteries (LIBs), which exhibit excellent performance, is considerably increasing in different industrial fields. During the manufacturing process of LIBs, it is necessary to join the cathode and anode sheets with thicknesses of several tens of micrometers to lead taps of the cathode and anode with thicknesses of several hundreds of micrometers. Ultrasonic welding exhibits excellent bonding when bonded with very thin plates, such as negative and positive electrodes of LIBs, and dissimilar and highly conductive materials. In addition, ultrasonic welding has a small heat-affected zone. In LIBs, Cu is mainly used as the negative electrode sheet, whereas Cu or Ni is used as the negative electrode tab. In this study, one or two electrode sheets (t0.025 mm Cu) were welded to one lead tab (t0.1 mm Cu). The welding energy and pressure were used as welding parameters to determine the welding strength of the interface between two or three welded materials. Finally, the effects of these welding parameters on the welding strength were investigated.