• Resources Recycling
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• v.23 no.2
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• pp.53-60
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• 2014

In order to separate Indium and Tin from spent indium tin oxide (ITO) sludge, direct hydrochloric acid leaching and thermal reduction followed by HCl leaching were applied. In case of direct leaching of spent ITO, leaching rate of In and Sn was 18.5% and 19.95%, respectively. Whereas, in case of thermal hydrogen treatment of ITO sludge at different temperatures such as $700^{\circ}C$, $800^{\circ}C$, $900^{\circ}C$ and $1100^{\circ}C$, followed by HCl leaching, we obtained the result of more than 97% leaching rate of Sn. Specially, thermal treatment at $800^{\circ}C$ showed the highest leaching rate of 98.2% of Sn. Precipitation method was used for separation and recovery of Sn from leached mixed solution. If the solution pH were adjusted 2.0, 99.69% of Sn precipitated and 10.3% of In was precipitated. This confirmed the possibility of separation of Sn and In from leached solution by precipitation method.

• Economic and Environmental Geology
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• v.53 no.4
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• pp.337-346
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• 2020

This study was carried out to evaluate the applicability of the soil washing process to remediation mercury-contaminated mine tailing or solid material (soil and sediments etc.) around abandoned mines. First, the physicochemical characteristics of mine tailing were analyzed through particle size analysis and sequential extraction. Secondly, laboratory scale washing experiments were performed using hydrochloric acid, nitric acid, potassium iodide and sodium thiosulfate. As a results of particle size analysis, mine tailing particle were concentrated below 40 mesh and the particle size below 200 mesh was the most analyzed. As a result of sequential extraction, elemental mercury fraction was analyzed as the highest with 69.12%, with strongly bound fraction 15.25% and residual and HgS fractions 11.97%, respectively. Laboratory scale washing experiments showed low applicability for nitric acid and sodium thiosulfate solutions. In case of hydrochloric acid solution, it was analyzed that mercury removal was possible at particle size of 200 mesh or more. Therefore, it is considered to be performed together with the physical sorting process. Potassium iodide solution was analyzed to have high washing efficiency at all concentrations and particle sizes. In particular, the mercury removal efficiency is high in the micro particles, and thus the applicability of the washing technology is the highest.

• Resources Recycling
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• v.15 no.6 s.74
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• pp.33-40
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• 2006

Leaching behavior of copper using electro-generated chlorine was investigated in hydrochloric acid solutions. When leached copper concentration was lower than 3.6g/L, the utilization efficiency of the electro-generated chlorine was close to 100% at $10mA/cm^2,\;25^{\circ}C$, 400 rpm in 1M HCl solutions. The concentration ot the leached copper over 3.6g/L caused the electrode potential to drop quietly, leading to a change or leaching mechanism. The leaching rate oi copper began to decrease at the concentration of copper 5.2g/L. This is probably due to the formation of a layer of CuCl on Cu metal in 1M HCl solutions. The leaching rate, however, was not retarded in a solution ot high chloride concentration. The high solubility of CuCl in the solution may prevent the formation of CuCl on Cu metal.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.1 no.2
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• pp.135-137
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• 1968

Bathythermograph (B. T) has been coumonly used to obtain a records of water temperature in the depth of 270m from the surface. We have, however, experienced some difficulties in obtaining smoked or coated glass which is used for the bathythermograph in this region, Therefore I introduce a easy method of preparing the smoked-glass slide. Preparing method is as follows. 1. Glass slides must be cleaned by dipping into the concentrated solution of sodium hydroxide ana hydrochloric acid then rinsing with hot water and polishing with a clean gauge. 2. The cleaned slide is immersed in the wax solution for coating, and dried on the filter paper. The Wax solution is prepared as follow : 1g of white wax is dissolved in 200CC of benzol or 1g of lard is dissolved in 300CC of gasoline. 3. A slide held in a fingertip is smoked on the flame of alcohol lamp, or Meter burner. When alcohol lamp is used the fuel alcohol must contain 1/5 of benzol, and when Meker burner is used, the air intake must be blocked up. The smoking on the glass slide should be light and uniform, after smoking the slide is cooled down. 4. The smoked glass slide is again dipped into the wax solution using a fingertip and the excessive wax solution on the slide is absorbed on the filter paper and drain off. 5. Thus prepared smoked slide can be used for B.T.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.1
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• pp.138-144
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• 2016

Titanium is resistant to general corrosion and in sea water because of the passivity layer film on the surface of material, but may be attacked by environments that cause breakdown of the protective oxide layer including hydrochloric, sulfuric and phosphoric acids. In this study, the Ti alloys were solution heat treatment 5hours at $1066^{\circ}C$ and $966^{\circ}C$, and followed by aging heat treated, 1, 4, 8 and 16 hours in $500^{\circ}C$, $600^{\circ}C$ and $650^{\circ}C$ respectively. The heat treated specimens were measured micro Vicker's hardness, and then accomplished electrochemical polarization test for comparing corrosion in 1N sulfuric acid solution. Additionally, micro structures were taken for corrosion tested specimens. The results showed that corrosion resistance was higher in solution heat treated alloy than base and age heat treated metal. Measured corrosion resistants were increased as increasing aging heat treatment time and temperature.

• Journal of the Korean Chemical Society
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• v.63 no.5
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• pp.327-334
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• 2019

Inhibition effects of cysteine(Cys), methionine(Met), and histidine(His) on the corrosion of cobalt were investigated in deaerated 0.5 M HCl and 0.5 M $H_2SO_4$ solution. All the inhibition efficiency (IE) in the amino acids for the cobalt corrosion depended on the mixed inhibition. However, IE in the solution of $H_2SO_4$ depended more on the anodic and in the solution of HCl on the cathodic inhibition. Amino acid adsorption process on cobalt surface in the solution can be explained by modified Langmuir isotherm. The molecules of histidine dissolved in both of the solution were physically adsorbed due to the electrostatic interaction between the surface of {$Co-Cl^{-{\delta}}$} and the {$-NH_3{^+}$} or {$-NH^+=$} of His. However the other cases of adsorption in this investigation can be explained by chemical adsorption between the empty d-orbital of Co and the lone pair of electron in S-atom in Cys and Met.

• Analytical Science and Technology
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• v.7 no.2
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• pp.201-204
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• 1994

Cation exchange column chromatography of lithium was carried out to investigate the lithium isotope separation in aqueous ion exchange system. A Pyrex glass column of $50cm{\times}6mm$ inner radius with a water jacket was used as the separation column in experiment. Upon column chromatography using hydrochloric and succinic acid mixtures as an elunent, single separation factor, ${\alpha}$, 1.0068 was obtained. From the experiment, it was found that $^6Li$ was enriched in the resin phase and $^7Li$ in the solution phase.

• Journal of Electrochemical Science and Technology
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• v.13 no.2
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• pp.237-253
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• 2022

The methyl 2-(1,3-dithietan -2- ylidene)-3-oxobutanoate (MDYO) and 2-(1,3-dithietan-2-ylidene) cyclohexane -1,3-dione (DYCD) were synthesized and tested at various concentrations as corrosion inhibitors for 316L stainless steel in 1 M HCl using weight loss, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), surface analysis techniques (SEM / EDX and Raman spectroscopy) and Functional Density Theory (DFT) was also used to calculate quantum parameters. The obtained results indicated that the inhibition efficiency of MDYO and DYCD increases with their concentration, and the highest value of corrosion inhibition efficiency was determined in the range of concentrations investigated (0.01 × 10^-3 - 10^-3 M). Polarization curves (Tafel extrapolation) showed that both compounds act as mixed-type inhibitors in 1M HCl solutions. Electrochemical impedance spectra (Nyquist plots) are characterized by a capacitive loop observed at high frequencies, and another small inductive loop near low frequencies. The thermodynamic data of adsorption of the two compounds on the stainless steel surface and the activation energies were determined and then discussed. Analysis of experimental results shows that MDYO and DYCD inhibitors adsorb to the metal surface according to the Langmuir model and the mechanism of adsorption of both inhibitors involves physisorption. SEM-EDX results confirm the existence of an inhibitor protective film on the stainless steel surface. The results derived from theoretical calculations supported the experimental observation.

• Applied Biological Chemistry
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• v.20 no.1
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• pp.43-57
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• 1977

In order to establish methods of potato processing for mixed cooking with rice as main diet, treatment for polyphenol oxidase inactivation in potato tissues, and safety in regard to sanitation were studied. The results were summarized as follows: 1. Cut potato granule which were blanched in boiling water are practical and best in color within $3{\sim}6\;minutes$ dipping. 2. Dipping treatment of potato granules in a saline solution is not pratical because of the resulting color and saline taste. 3. Dipping treatment of potato granules in a boiling saline solution is not practical because of residual salt. 4. Dipping treatment of potato granules in low concentration of hydrochloric acid solution is not effective in color changes but dipping treatment from 0.1N concentration for 4-10 minutes to 0.5N concentration for $1{\sim}10minutes$ shows good effects. 5. Dipping treatment in boiling hydrochloric acid solution of 0.04-0.068N concentration for 3-5 minutes dipping is practical for its resulting color. 6. Dipping treatments in 0.05% of $K_2S_20_5$ solution for $50{\sim}60\;minutes$ and in 0.06% for $40{\sim}60\;minutes$ and 0.065% for $10{\sim}60\;minutes$ shows a small palatability in color but its boiled potato granules shows good color 7. Treatments for any time in $0.01{\sim}0.03%$ of boiling $K_2K_20_5$ solution after predipping in its cold solution for longer time than 30minutes show effective in the color and palatability of the potato granules and their cooked ones. 8. From the view of food sanitation, dipping treatment of the potato granules in the solution of $K_2S_20_5$ is safe because of the few residual amount of $SO_2$. 9. All the methods of treatment that potato granules are dipped for any time at 0.01% of $K_2S_20_5$ solution are safe from the view of fond sanitation. At 0.03% of $K_2S_20_5$ solution, nothing but the methods of treatment that they are dipped within 30 minutes and boiled within 4 minutes are safe.

• Journal of Chest Surgery
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• v.12 no.4
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• pp.395-402
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• 1979

Intracellular pH was determined by distribution of 5.5-dimethyl-2,4-oxazolidlnedione [DMO]in the skeletal muscle of dogs before and after lactic acidosis induced by intravenous infusion of lactic acid solution. After infusion of lactic acid solution arterial pH decreased from 7.40 to around 7.12 [P<0.001]and metabolic acidosis was induced. However, dose-pH change response was not proportional as in the case of hydrochloric acid infusion. During lactic acidosis, intracellular pH changed very little except when venous blood $pCO_2$ increased significantly. The decrease of intracellular pH in lactic acidosis might be due primarily to the increase of intracellular $pCO_2$. And during lactic acidosis, change of extracellular pH was larger than that of intracellular pH, and this was also the case of change In hydrogen Ion concentration in extracellular and intracellular fluid. The fact was estimated that exogenous lactic acid transported into the cell does not contribute to pH change by the participation in the metabolism. Change in plasma potassium Ion concentration was not eminent as metabolic acid-base disturbances by other origin, and changing pattern of Hi/He ratio was not same as Ki/Ke ratio. In spite of no changes in extracellular potassium ion concentration after exogenous lactic acidosis total amount of potassium ion in extracellular fluid increased from 12.62mEg to 18.26mEg [P< 0.05].