• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.6
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• pp.26-33
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• 2012

This paper reported on the effect of blended activator on the physical properties of alkali-activated slag mortar. Five different activators(caustic alkalis) were used: sodium hydroxide(NaOH, A Case), calsium hydroxide($Ca(OH)_2$, B Case), magnesium hydroxide($Mg(OH)_2$, C Case), aluminum hydroxide($Al(OH)_3$, D Case), and potassium hydroxide(KOH, E Case). We blended five caustic alkalis with sodium carbonate($Na_2CO_3$). The dosage of five caustic alkalis was 3M and sodium carbonate was 1M, 2M and 3M. The result of flow and setting time was decrease as the dosage of sodium carbonate increase. But the compressive strength was increase as the dosage of sodium carbonate increase. It was shown that there is a good effect of blended caustic alkalis with sodium carbonate in alkali-activated slag mortar.

• Journal of the Korean Ceramic Society
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• v.41 no.12 s.271
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• pp.889-892
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• 2004

Acicular type aragonite precipitated calcium carbonate was synthesized by carbonation reaction of $Ca(OH)_2$ slurry and $CO_2$ gas. As increasing the initial concentration of $Mg^{2+}$ ion, calcite crystal phase substantially decreased while that of aragonite crystal phase increased. According to XRD and EDS analysis, it was found that the addition of $MgCl_2$ induced the $Mg^{2+}$ ion to substitute in $Ca^{2+}$ ion site of calcite lattice then the unstabled calcite structure be resolved, consequently the growth of calcite structure is interrupted while the growth of aragonite structure is expedited.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.11
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• pp.1205-1211
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• 2004

This study has investigated radiation degradation of chloroprene rubber in the presence of some fire retardant. Ammonium polyphosphate, aluminium trihydroxide, magnesium hydroxide, calcium carbonate and antimony trioxide were selected as flame retardant. Samples were irradiated using a Co$^{60}$ ${\gamma}$ -ray and ray up to 2000 kGy at a dose rate of 5 kGy/hr in the presence of air atmosphere at room temperature. After irradiation, samples were assessed fire retardancy with electrical properties and mechanical properties. Some considerations concerning the effects of the fire retardants added to chloroprene rubber on the radiation and thermal stability of chloroprene rubber are presented. From fire retardancy with electrical and mechanical property measurements, it was found that addition of magnesium hydroxide resulted in maximum fire retardant effect.

• Journal of the Korea Concrete Institute
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• v.24 no.6
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• pp.745-752
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• 2012

This paper studies the effect of the compressive strength for combined alkali-activated slag mortars. The effect of activators such as alkali type and dosage factor on the strength was investigated. The alkalis combinations made using five caustic alkalis (sodium hydroxide (NaOH, A series), calcium hydroxide ($Ca(OH)_2$, B series), magnesium hydroxide ($Mg(OH)_2$, C series), aluminum hydroxide ($Al(OH)_3$, D series), and potassium hydroxide (KOH, E series)) with sodium carbonate ($Na_2CO_3$) were evaluated. The mixtures were combined in different dosage at 1M, 2M, and 3M. The study results showed that the compressive strength of combined alkali-activated slag mortars tended to increase with increasing sodium carbonate. The strength of combined alkali-activated slag mortars was better than that of control cases (without sodium carbonate). The result from scanning electron microscopy (SEM) analysis confirmed that there were reaction products of calcium silicate hydrate (C-S-H) and alumina-silicate gels from combined alkali-activated slag specimens.

• Journal of the Korean Ceramic Society
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• v.20 no.3
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• pp.193-198
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• 1983

This experiment has been carried out for the purpose of investigating the effect of $V_2O_5$ and $H_3BO_3$ additives on sintering of magnesium oxide over the temperature range of 1300-150$0^{\circ}C$ MgO powder has been obtained by calcin-ing extra reagent grade magnesium carbonate(basic) at 90$0^{\circ}C$ for 30 minutes. The specimens were prepared by compression with pressure of 700Kg/cm2 then fired at 1300-150$0^{\circ}C$ for 0-5hrs. Sintering behaviour and microstructure of fired specimens were examined. Densification rates obeyed the equation D=K 1n t+C. The ratio of density in case of addition of $V_2O_5$ to theoretical density of pure periclase was 95-99% Activation energy of densification in case of $V_2O_5$ addition was 30.15 Kcal/mole. The range of average grain size in case of addition of $V_2O_5$ was 40-50$\mu\textrm{m}$. $H_3BO_3$ addtivie had not an effect on densification of MgO.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.1
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• pp.18-24
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• 2016

Mineral carbonation is a technology for permanently storing carbon dioxide by reacting with metal oxides containing calcium and magnesium. In this study, we used sea water and alkaline industrial by-product such as paper sludge ash (PSA) for the storage of carbon dioxide through direct carbonation. We found the optimum conditions of both sea water content (mixing ratio of sea water and PSA) and reaction time required in the direct carbonation through various experiments using sea water and PSA. In addition, we compared the amounts of carbon dioxide storage with the cases when sea water and ultra-pure water were separately used as solvents in the direct carbonation with PSA. The amount of carbon dioxide storage was calculated by using both solid weight increase through the carbonation reaction and the contents of carbonate salts from thermal gravimetric analysis. PSA particle used in this study contained 67.2% of calcium. The optimum sea water content and reaction time in the carbonation reaction using sea water and PSA were 5 mL/g and 2 hours, respectively, under the conditions of 0.05 L/min flow rate of carbon dioxide injected at $25^{\circ}C$ and 1 atm. The amounts of carbon dioxide stored when sea water and ultra-pure water were separately used as solvents in the direct carbonation with PSA were 113 and $101kg\;CO_2/(ton\;PSA)$, respectively. The solid obtained through the carbonation reaction using sea water and PSA was composed of mainly calcium carbonate in the form of calcite and a small amount of magnesium carbonate. The solid obtained by using ultra-pure water, also, was found to be carbonate salt in the form of calcite.

• Analytical Science and Technology
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• v.13 no.2
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• pp.158-165
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• 2000

The purity of gypsum and quantitation of impurities of flue gas gypsum will not only play an important role in deciding of the optimal condition during a trial run of FGD (flue gas desulfurization), but also can be utilized in quality control of gypsum. The purity of gypsum can be determined from combined water, sulfur trioxide and calcium concentration. We found that the thermal analysis by TGA (thermogravimetric analysis) was the most accurate and convenient method to determine the purity of gypsum. This method will be done in a hour and the results were reproducible. On the other hand, the best way of the analysis of impurities in gypsum was fusion method using $LiBO_2$ as a fusion agent. We also determined the amount of $CO_2$ gas to analyze magnesium carbonate and calcium carbonate contents. The analyses of combined water by TGA, fusion method followed by ICP-AES (inductively coupled plasmaatomic emission spectroscopy) and determination of $CO_2$ amount can lead to more accurate and convenient method for gypsum analysis.

• Journal of Veterinary Clinics
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• v.30 no.6
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• pp.503-505
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• 2013

A cross breed dog (6-year-old, 6 kg, intact male) was referred with hematuria. The dog had been treated for years owing to the urinary bladder calculi. On abdominal radiography, prostatic calculus was demonstrated in the prostatic area. In addition, ultrasonography and computed tomography (CT) scan would confirm that the part of calculus protruded within the prostatic urethra. The patient underwent a prostatolithotomy and traumatic prostatic urethra was carefully sutured and the omentum was filled with the prostate lumen. A crystallographic analysis of the stone showed 80% magnesium ammonium phosphate (struvite) and 20% carbonate apatite. The leakage of the urine was not observed post-operation and the hematuria improved and there was no specific problem at the 6 months follow-up.

• Korean Journal of Microbiology
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• v.8 no.1
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• pp.41-51
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• 1970

In previous paper, it was reported that antibiotic substance such as tetracycline and streptomycin were produced by S'. albus subsp. and S'. globosus. And increase of mycelial growth of two strains, antibiotic production, and changes of pH range are extended to approximately 110-130 hrs in fermenting medium, there-after they decreased with culture period exception of pH range. Two Streptomyces spp. required commonly 4-5% starch as carbon sources and 1.5-2.0% soybean meal as nitrogen sources. However, 0.005-0.01M potassium phosphate dibasic, calcium carbonate (6mg/ml in S.albus subsp. and 2mg/ml in S. globosus), 0.01-0.03M, magnesium sulgate and 0.01M ferric chloride showed as optimal concentration for the growth of 2 strains. Mineral compoments such as zinc, manganese, cobalt, sodium and copper at the level of 10$^{-4}$ -10$^{-6}$ M were observed. Especially, zinc ion showed toxicity to the growth of 2 strains at 0.005M. In relation with pH, there is a little difference in mycelial growth with cultural initial pH.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.2
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• pp.183-188
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• 1993

This experiment was conducted to investigate the effect of sulfur containing fertilizers on growth, yield and nutritive quality of soybean as affected by lime application at reclaimed soil. Lime application for neutralization requirements showed the effect of increased grain yield about 32% compared to the non application at newly opened land of red and yellow soil. In case of lime application, the sulfur containing fertilizers combined with super phosphate, ammonium sulfate, and gypsum increased the grain yield by 31%, 11%, and 3%, respectively. When lime was not applied, magnesium carbonate application increased the yield by 47%, super phosphate by 22%, and gypsum by 15%. The protein content of grain was higher at lime application than those of non lime application and was increased by the application of sulfur containing fertilizer. But lipid content was not affected by lime or sulfur application. From the above results obtained it was concluded that sulfur fertilizer effect under lime application was significant when combined with super phosphate or ammonium sulfate application. Magnesium carbonate or super phosphate application was the best combination with sulfur-containing fertilizer.