• Journal of the Mineralogical Society of Korea
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• v.19 no.3 s.49
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• pp.129-138
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• 2006

In this study, we identified the secondary precipitates from Samsan-jeil and Sambong mine, Goseong, Gyeongnam by means of scanning electron microscopy, electron probe microanalysis and X-ray powder diffraction analysis. Copper sulfide minerals had been produced from the mines during last few decades, however they are not worked. White and blue precipitates were found at the downstream of mine rock dump at Sambong mine and green one was at Samsan-jeil mine. The white precipitate covered the host rock surface with thickness of $30{\mu}m$, and is a kind of diatom with $10{\mu}m$ in length and $3{\mu}m$ in width. It is a species Fragilaria constuens, which is contained a order Pennales(pennate diatom) and lives in fresh water. The blue precipitate is the alteration product of chalcopyrite. It resultes in the increase in the ratio Cu:Fe from 5 to 13. The green precipitate has worm-like morphology with $10{\sim}20nm$ in diameter and $200{\sim}300nm$ in length. It is mainly composed of secondary copper sulfate such as woodwardite. However, it could be formed by the activity of microorganism, because the copper content is more than any secondary copper sulfate reported in copper sulfide mine. In order to identity the green precipitate exactly, the further research is needed.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.307-310
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• 2004

Micellar enhanced ultrafiltration (MEUF) is a surfactant-based separation process and it can remove heavy metal ions from aqueous stream effectively. However, it is necessary to recover and reuse surfactants for economic feasibility because surfactant is expensive. Foam fractionation was investigated for both anionic and cationic surfactant recovery. Chelating agent such as ethylenediaminetetraacetic acid (EDTA) was studied for the separation of heavy metals from surfactant solution. Anionic surfactants bound with heavy metals can be recovered by lowering pH (acidification). In this study, citric acid and imminodiacetic acid (IDA) were applied to release copper from sodium dodecyl sulfate (SDS) micellar solution and compared with EDTA. Precipitation of copper by ferricynide and sodium sulfide were also investigated. As a result, ca. 100 % of copper was released from SDS micellar solution by 5 mM of EDTA and citric acid. And 3.3 mM of ferricyanide formed precipitate with 82.7 % of copper. 5 mM of IDA and sodium sulfide released or formed precipitate 82.5 % and 58.9 % of copper, respectively. Citric acid is harmless to environments and ferricyanide precipitates with Cu easily. Therefore, it is considered that citric acid and ferricyanide have competiveness over a famous chelating agent, EDTA, for the separation of Cu from SDS solution.

• Bulletin of the Korean Chemical Society
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• v.16 no.5
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• pp.422-427
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• 1995

In a stream of water sample, trace metal ions are quantitatively coprecipitated with Indium hydroxide and filtered. The filtered precipitate is continuously dissolved in 3 M nitric acid and introduced to ICP directly. The lead, cadmium, and copper are concentrated more than 10-fold and determined with ICP-AES at a sampling frequency of 10/hour. The detection limits are 2.89, 1.43,0.52 ppb for lead, cadmium, and copper respectively. Recoveries of lead, cadmium, and copper are 98.7, 94.3, and 104.5% respectively. The RSD values for three elements are about 3-5% currently.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.7
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• pp.131-138
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• 2008

The microstructural effects on the ultrasonic nonlinearity were investigated in isothermally degraded ferritic 2.25Cr-1Mo steel and low cycle fatigued copper. The variation in ultrasonic nonlinearity (${\beta}/{\beta}_0$) was interpreted as resulting from microstructural changes supported by the electron microscopy and X-ray diffraction, in addition to the mechanical test (Victor's hardness and ductile-brittle transition temperature). The ultrasonic nonlinearity of 2.25Cr-1Mo steel increased abruptly in the initial 1,000 h of degradation, and then changed little due to the coarsening of carbide and precipitation of stable $M_6C$ carbide during isothermal degradation. The ultrasonic nonlinearity of copper increased with the fatigue cycles due to the evolution of dislocation cell substructure.

• Economic and Environmental Geology
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• v.30 no.4
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• pp.379-393
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• 1997

Geology of the Zbezkazgan copper deposit in Kazhkstan is mainly composed of Permian and Carboniferous sedimenary rocks in which copper minerals are mainly contained in grey sandstone of Carboniferous age. There are 28 layers of copper ore bodies in Zbezkazgan suite. Thickness of the ore bodies ranges from one to 35 meters, grade of the crude ore ranges from 2 to 5 wt % Cu and the extension of the orebodies is 5 to 7 km. Microscopic study on specimens from the Zbezkazgan ore deposit has exposed clues to understand the origin of this deposit. Alternatively deposited grey sandstone and red sandstone are mainly composed of quartz and feldspar grains. A big difference between the grey sandstone and the red sandstone is in grain size, the former is larger than the latter. Chalcocites as main copper minerals have cemented through grain boundary. It is assumed that quartz, feldspar and copper were derived from granitoid in which copper mineralization had taken place before exposing to weathering. The chalcocites were precipitated by a sudden change of geochemical condition (Eh, pH, temperature, etc.) of fluid which had carried quartz, feldspars, copper ions and sulphate during formation of grey sandstones. The copper ions and sulphate were stable in fluid during sedimentation of oxidation environment, however, the copper ions were no more stable at the reduced environment and changed to stable forms to precipitate copper minerals by reaction of copper ions and hydrogen sulfides. This chemical precipitation of copper minerals in the sandstone attributes to the assumption of hydrothermal origin on this sedimentary origined deposit.

• Resources Recycling
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• v.23 no.3
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• pp.37-43
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• 2014

A study has been made on the recovery of tin and copper from waste solder stripper by oxalate precipitation. With the increasing of the oxalic acid addition, tin was precipitated effectively and removed above 99.5% of tin when the oxalic acid, in an amount 1.0-1.5 times the stoichometric requirement, was added. But, in this case, only 2.0% of copper was precipitated and lead, iron were not precipitated. So, tin was selectively removed from the waste solution. With the increasing of the reaction temperature, the removal percentage of tin was increased and maximum value at arounf $60^{\circ}C$ and decreased with increase in the temperature any more. After filtering the precipitate and drying in oven, $SnO_2$ was obtained from the precipitate. After removal of tin in stripping solution, above 91% of copper was selectively removed by Cu-oxalate by addition of oxalic acid.

• Journal of the Mineralogical Society of Korea
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• v.17 no.1
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• pp.1-9
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• 2004

Copper(II) sorbed on kaolinite (KGa-lb) was studied using electron paramagnetic resonance (EPR) and extended X-ray absorption fine structure (EXAFS) spectroscopy. The sorbed copper(II) had an isotropic EPR signal with $g_{iso}\;=\;2.19$ at room temperature. At 77 K, the isotropic signal converted to an axially symmetric anisotropic signal with $g_{\$\mid$}\;=\;2.40,\;g_{\bot}\;=\;2.08,\;and\;A_{\$\mid$}\;=\;131\;G$. These EPR results suggest that the sorbed copper(II) forms an outer-sphere surface complex with a tetragonally distorted $CuO_{6}$ octahedral structure on the kaolinite. In the sorption measurement, the amount of sorbed copper increased with increasing pH of the solution. However, the intensity of the isotropic EPR line was not directly proportional to the amount of sorbed copper. This discrepancy was resolved by assuming the formation of a surface precipitate at higher pH that is invisible by EPR. The EXAFS data confirmed the existence of the surface precipitate. The best fit for the EXAFS of the sorbed copper showed that each copper on the kaolinite had 6.8 copper neighbors located $3.08\;{\AA}$ from it, in addition to the first shell oxygen neighbors, including 4 equatorial O at $1.96\;{\AA}$ and 2 axial O at $2.31\;{\AA}$. This work shows that the local environment of the copper sorbed on the kaolinite changes as a function of pH and surface loading, and that the EPR and EXAFS are useful in studying such changes.

• YAKHAK HOEJI
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• v.9 no.1_2
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• pp.18-22
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• 1965

A new organic reagent, 1-isonicotinoyl-2-furfurylidene hydrazine was synthesized from isonicotinic acid hydrazide and furfural, gives precipitate with copper(II), mercury(II) and argent(I), whereas, it gives a water soluble yellow complex with iron(III). Copper complex of the reagent is soluble in EtOH MtOH, pyridine, dioxane and dimethylformamide with green yellow coloration. The complex has a maximum absorption at 385 m.$\mu$ and molar ratio of copper; reagent was estimated as 1:1 by continuous variation method, slop method and chelate titration method. Molar extinction coefficient (9600) and apparant formation constant of this complex was spectrophotometrically determined. K=1.7 * $10^{7}$ (Babko's method) K=2.1 * $10^{7}$ (Anderson's method). This reagent reacted with copper so sensitive that it would be available for determination of Cu (II).

• Journal of the Korean institute of surface engineering
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• v.42 no.5
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• pp.246-249
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• 2009

Cu-Ti alloys with titanium in the range of 0.5-6.0 wt% were developed to evaluate the effect of the titanium content and heat treatment on microstructure, hardness, and electrical conductivity. The hardness of the Ti-added copper alloys generally increased with the increase in titanium content and hardening was effective up to the 2.5 wt%-Ti addition. Microstructural examination showed that the second phase of $Cu_4Ti$ started to precipitate out from the 3.0 wt% Ti-addition, and the precipitate size and volume fraction increased with further Ti addition. Aging of the present Cu-Ti alloys at $450^{\circ}C$ for 1 h increased the hardness; however, the further aging up to 10 h did not much change the hardness. In the present study, it was inferred that in optimal Ti addition and aging condition Cu-Ti alloy could have the hardness and electrical conductivity values which are comparable to those of commercial Cu-Be alloy.

• Applied Microscopy
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• v.36 no.2
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• pp.47-55
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• 2006

In this paper a transmission electron microscope (TEM) observation of fine Cu precipitates distributed randomly in Al-2.5Cu-1.5Mg wt.% alloy is first reported. This new observation happened to occur when an ion milling was peformed to remove oxides on the specimen, particularly, aged 100 hours at $150^{\circ}C$. Meanwhile the oxides were identified to be $Cu_2O$ particles. For this work involved with analysis of diffraction rings, the formulation of the electron diffraction rings pattern for powder particles was made. Finally the significance of this unexpected ion milling effort on the alloy was discussed