• 자원리싸이클링
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• 제18권2호
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• pp.56-61
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• 2009

알루미늄 화합물을 합성하기 위한 전단계 연구로써, 국산 99.7% 순도의 수산화알루미늄을 대상으로 무기산 및 유기산을 이용한 용해실험을 수행하였다. 본 실험에서 사용한 수산화알루미늄의 평균입도는 각각 $14.4{\mu}m$, $22.9{\mu}m$ 및 $62.3{\mu}m$이었으며, 반응온도, 산농도, 반응시간에 따른 수산화알루미늄 용해율을 조사하였다. 실험결과 염산에 의한 용해시 염산농도가 증가할수록 용해율은 증가하였으며, $70^{\circ}C$에서 4시간 용해시 염산농도 5 mole/l의 경우 70% 이상의 용해율을 보였다. 또한, 황산을 사용하여 수산화알루미늄을 용해하고자 하는 경우 적정 황산농도는 6 mole/l 부근으로 유지하는 것이 바람직하였다. 옥살산을 사용하는 경우 반응온도는 $90^{\circ}C$가 적절하며, 옥살산농도 1.0 mole/l, 고체농도 20 g/l의 조건에서 16시간 용해하였을 때 거의 100%에 근접하는 용해율을 얻을 수 있었다.

• Journal of Pharmaceutical Investigation
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• 제20권3호
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• pp.121-127
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• 1990

Mefenamic acid has been widely used clinically as an anti-inflammatory analgesic. It has poor solubility in water $(41\;{\mu}g/ml)$ and there is the difficulty of dissolution in the mefenamic acid capsules. A study was made to investigate the effect of various surfactants on the dissolution of mefenamic acid capsules. The surfactants used were sodium lauryl sulfate (SLS), Pluronic F-68, F-77, and F-127. Mefenamic acid capsule containing surfactant showed significantly improved dissolution characteristics. The dissolution rate was fast in the order of SLS > F-77 > F-68 > F-127 in mefenamic acid capsules containing 0.2 w/w % surfactant. SLS was selected for further study on the bioavailability in rabbits. The area under the plasma concentration-time curve $(AUC_{0-24})$ of mefenamic acid capsule containing SLS was higher than one of mefenamic acid capsule not containing surfactant.

• Journal of Pharmaceutical Investigation
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• 제22권4호
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• pp.307-315
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• 1992

Dissolution rate of practically insoluble mefenamic acid was improved by roll mixing with sodium lauryl sulfate (SLS) or polyvinylpyrrolidone (PVP). The dissolution rate of the drug roll mixtures with SLS was superior to that of roll mixtures with PVP. The maximal dissolution rate was found in the roll mixtures system with SLS content of 60%. The dissolution rate of mefenamic acid roll mixtures with SLS content of 60% reached to the maximum value after 10 min of roll mixing. The transport of roll mixtures with SLS across rat jejunum was studied by the perfusion method using everted rat jejunum in vitro. The absorption rate of roll mixtures was superior to that of mefanamic acid.

• 동아시아식생활학회지
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• 제10권3호
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• pp.239-244
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• 2000

Effects of acetic acid, malic acid and citric acid on copper dissolution from new and used copper saucepans at different concentrations (0, 0.02. 0.04, 0.1 0.2, 0.4, 1.0, 2.0, 4.0%), different boiling times (0,10, 20. 30, 40, 50, 60mins.), and different temperatures (5, 20, 40, 60, 80, 10$0^{\circ}C$ ) were investigated. As acetic acid concentration increases, copper content increases. Copper dissolution concentration from copper saucepans at boiling in malic acid increases more than in acetic acid or citric acid. At above 6$0^{\circ}C$, as the temperature increases, the concentration of copper dissolved from copper saucepans also increases. As boiling time increases, the concentration of copper dissolved from copper saucepans also increases. In addition, through repeated use, the concentration of copper increases as well. And copper concentration dissolves in large amounts from used saucepans rather than new saucepans. The dissolution of copper with distilled water by repeated use does not dissolve at all. 1% acetic acid dissolves in large quantities.

• Korean Chemical Engineering Research
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• 제55권5호
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• pp.711-717
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• 2017

A fundamental study was conducted on the dissolution of North Korean magnesite using hydrochloric acid to understand the dissolution behavior of the magnesium and impurities. The influence of the acid concentration, particle size of the magnesite, reaction temperature, and pulp density on the dissolution of magnesium, iron, calcium, aluminum, and silicon dioxide was studied. The experimental results showed that 98.5% of magnesium, 86.9% of iron, 87.3% of calcium, 23.6% of aluminum, and 20.4% of silicon dioxide were dissolved when magnesite particle sizes within the range of $75{\sim}105{\mu}m$ were reacted using 3 M HCl solution under 6% pulp density at 363 K for 3 h. The residues that remained after the dissolution were silicon dioxide, talc, and clinochlore.

• 환경위생공학
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• 제16권4호
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• pp.62-68
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• 2001

The advantages of hydrogen peroxide dissolution method were no discharge of noxious matter when dissolution of iron wire which used as the center supporter, reactions occur in room temperature and easy to recover dissolved iron. This study was aimed at gathering the basic data of iron wire dissolution- recovery process and proposes the reaction condition of iron wire dissolution- recovery process rind the factors influencing those reactions. The results were as follows : 1 . Hydrogen peroxide dissolution method used hydrochloric acid as the catalyst. 1. In the dissolution of iron wire(1.668 g), the condition of reaction was E1702(30 ml), HCI(20 ml) and $H_2O$(200 ml) ; time of the reaction was 18 min. P.W.(Piece weight) was 7.75 mg, and C.R. was $2.34{\;}{\Omega}$ 2. In the dissolution of iron wire(1.529 g), the condition of reaction was H7O2(30 ml), HCI(20 ml) and $H_2O$(200 ml), time of the reaction was 21 min., P.W.(Piece weight) was 7.73 mg, and C.R. was $2.35{\;}{\Omega}$. Hydrogen peroxide dissolution method used sulfuric acid as the catalyst. 1. In the dissolution of iron wire(0.834 g), the condition of reaction was $H_2O$(65 ml), $H_2SO_4$(5 ml) and 1702(5 ml) ; time of the reaction was 5 min.30 sec, P.W.(Piece weight) was 7.74 mg, and C.R. was $2.33{\;}{\Omega}$ 2. In the dissolution of iron wire(1.112 g), the condition of reaction was $H_2O$(65 ml), $H_2SO_4$(5 ml) and $H_2O_2$(5 ml) ; time of the reaction was 4 min.30 sec, P.W.(Piece weight) was 7.75 mg, and C.R. was $2.33{\;}{\Omega}$. Hydrogen peroxide dissolution method used hydrochloric acid and sulfuric acid as the catalyst confirmed a clean technology, because there were not occurred a pollutant discharged in the existing method.

• 한국물환경학회지
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• 제23권1호
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• pp.81-86
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• 2007

This paper describes a study on the role of limestone which might affect the dissolution of phosphates when phosphate containing sediments are put under anaerobic conditions. A small quantity of calcium hydroxy-apatite, alone or mixed with limestone powder, was put in contact with aqueous solution of acetic acid or carbonic acid, and variations of phosphate concentration were determined time dependantly. The results showed that the concentration was remarkably low in the presence of limestone, signifying that the coexistence of limestone suppresses the dissolution of phosphate by organic acid and/or carbonic acid. Separate experiments conducted by developing an anaerobic condition, after mixing lake sediments with dried leaves and limestone, showed that the existence of limestone suppressed the dissolution of phosphate. These results show that the application of limestone might be a useful measure to prevent deterioration of water quality originated from eutrophication by inhibiting the internal loading of P in eutrophic water-bodies.

• 방사성폐기물학회지
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• 제10권2호
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• pp.77-85
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• 2012

본 연구는 우라늄-함유 석회침전물로부터 U을 제거(/회수) 하기위하여 탄산염 산화용해-산성화 침전과 질산용해-과산화수소 침전을 각각 고찰하였다. 석회침전물 내 우라늄을 용해하는 관점에서는 질산용해가 유리하나 (약 98% 이상 용해) 이 경우 U과 Al, Ca, Fe, Mg, Si 등의 공존 불순물이 다량 공용해되고, 또한 과산화수소 침전에서도 상당량의 불순물이 U과 함께 공침전 된다. 한편 탄산염 용해에 의한 산성화 침전은 우라늄의 용해가 90% 이하로 방사성 고체페기물의 부피감용 측면에서는 질산용해 보다 덜 효율적이지만, 우라늄과 불순물의 공용해나 산성화 침전에 의한 우라늄과 불순물의 공침전이 거의 일어나지 않아 보다 순수한 U을 회수하는 측면에서는 매우 효과적이다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
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• pp.393-396
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• 2003

Soil contains the several kinds of metal oxides. Magnetite in soil may contribute the generation of secondary waste during the decontamination of soil by citric acid. Dissolution of magnetite powders by citric acid was investigated in the pH range between 2.0 and 5.0. The dissolution behaviour of magnetite was well described by the equation, A[1 - $e^{-B(x-c)}$]. The parameters of the equation were optimized by the iteration method, and the physical meaning of each parameter was explained. Concentration of each of the dissociated chemical species of citric acid was calculated using the ionization constants. The dissolution reaction was explained by the concentration of the dissociated chemical species of citric acid.d.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.237.1-237.1
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• 2003

Cefuroxime axetil, a broad spectrum antibiotic, has been known to form a gelatinous mass in contact with aqueous media, which could lead to poor dissolution. Therefore, this study was conducted for removing the gelling phenomenon and thereby obtaining a favorable dissolution profile. We have found that the addition of poly (methacrylic acid, methyl methacrylate) could not only inhibit the tendency of cefuroxime axetil to form a gel but also showed the good dissolution profile compared to the formula without poly (methacrylic acid, methyl methacrylate). (omitted)