• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.2
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• pp.121-127
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• 2010

The in-furnace desulfurization technique is applied to the $O_2/CO_2$ combustion system for the carbon capture and storage (CCS) process because this combustion system does not need an additional chamber for the desulfurization. $CaCO_3$ sorbent particles, which have a wide range in size from a few nanometers to several tens of micrometers, are used for this process. In this study, an experimental system which can simulate the $O_2/CO_2$ combustion system was developed. $CaCO_3$ sorbent particles were exposed to the high temperature reactor at $1200^{\circ}C$ with various residence times (0.33-1.46 s) in air and $CO_2$ atmospheric conditions, respectively. The sorbent particles were then sampled at the inlet and outlet of the reactor and analyzed qualitatively/quantitatively using SMPS, XRD, TGA, and SEM. The results showed that the residence time and atmospheric condition in a high temperature reactor can affect the characteristics of the $CaCO_3$ sorbent particles used in the in-furnace desulfurization technique, such as the calcination rate and reaction mechanism.

• Elastomers and Composites
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• v.51 no.4
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• pp.286-300
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• 2016

$MoS_2$ precursors were synthesized by reacting thioacetamide ($C_2H_5NS$) with sodium molybdate dihydrate ($Na_2MoO_4{\cdot}2H_2O$) in aqueous HCl solution. $MoS_2$ nanoparticles were prepared from dried $MoS_2$ precursors by calcination in an electric furnace at $700^{\circ}C$ for 2 h under an inert argon atmosphere. $MoS_2-C_{60}$ nanocomposites were obtained by heating $MoS_2$ nanoparticles and fullerene ($C_{60}$) together in an electric furnace at $700^{\circ}C$ for 2 h. Their morphological and the structural properties were characterized by powder X-ray diffraction and scanning electron microscopy. The $MoS_2$ nanoparticles and $MoS_2-C_{60}$ nanocomposites were used as catalysts in the reductions of 2-, 3-, and 4-nitrophenol in the presence of sodium borohydride. The photocatalytic activities of the $MoS_2$ nanoparticles and $MoS_2-C_{60}$ nanocomposites were evaluated in the degradation of organic dyes (brilliant green, methylene blue, methyl orange, and rhodamine B) under ultraviolet light (254 nm).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.11a
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• pp.65-66
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• 1994

This paper describes study on the preparation of ferrite powder for bonded mallets. The specimen which has the basic composition of SrO$.$nF$_2$O$_3$ with n=5.9 is in nonstoichiomatric region. Calcination is performed under N$_2$ atmosphere 1175$^{\circ}C$, 1200$^{\circ}C$, 1225$^{\circ}C$, 1250$^{\circ}C$ and 1275$^{\circ}C$ respectively. Then, Cooling is carried out in the furnace. In order to increase coecivity and obtain uniform grain size, we add to the specimen 0.7wt%CaCO$_3$, 0.3wt % SiO$_2$, 0.5wt%Na$_2$SiO$_3$ and 0.5wr% Al$_2$O$_3$. Also, in order to increase milling effect, carbon coating on sample particles is tried. As the result, single magnetic domain partic1e with Size of 1$\mu\textrm{m}$ in obtained and magnetic properties are improved.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.2
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• pp.168-177
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• 2015

Shell waste from the butter clam Saxidomus purpuratus and littleneck clam Ruditapes philippinarum is a large by-product of shellfish aquaculture, and it is desirable to convert it into value-added products for industrial applications. In this study, calcium carbonate (CaC) polymorphs from butter clam (BCSP) and littleneck clam (LCSP) shell powders and commercial CaC were characterized using Fourier transmission infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The results revealed that the optimal calcination conditions to eliminate organic substances and improve solubility for both BCSP and LCSP were $800^{\circ}C$ for 8 h in an electrical furnace. Calcination improved the white index of the butter clam (BCCP) and littleneck clam (LCCP) calcined powder compared with shell powders. The calcium content in BCCP (51.1%) was higher than that of LCCP (44.9%) or commercial calcium oxide (CaO, 44.7%). The XRD patterns of BCCP and LCCP were similar to that of CaO. Cubic-like crystals of CaC and irregular crystals of BCCP and LCCP were observed by SEM. The FT-IR and XRD analyses revealed the presence of calcite and aragonite in the BCSP and aragonite in the LCSP, whereas the CaC contained calcite. These results indicate that butter and littleneck clam shells are potential biomass resources for calcium carbonate and calcium oxide.

• Resources Recycling
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• v.7 no.5
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• pp.19-25
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• 1998

High temperature thermal behaviors of EAF dust by coke at initial reaction stage were studied to obtain the fundamental data of EAF dust treatment process, that is Extended Arc Plasma Furnace System called RAPID system. In this study thermal behaviors including calcination of limestone, devolatilization of EAF dust itself, and reduction & devolatilization of mixture(EAF dust : coke : limestone = 80 : 10 : 10 wt.%) were investigated as functions of reaction temperature (1000~1300$^{\circ}C$) and reaction time (3~12 min), considering the 180% equivalence of carbon reduction and 1.7 bacisity for optimum reduction and melting of EAF dust in the RAPID system. Size of sample was about below 0.1 mm for these experiments. Limestone was completely calcined at above 1100$^{\circ}C$ within 1 minutes. In the case of devolatilization of EAF dust itself, weight loss of EAF dust was about 14% at 1300$^{\circ}C$ and 12 minutes, and partial sintering and melting were found in part of sample. Weight loss of mixtures increased with increasing reaction temperature and time, about 46% weight loss in it was occurred at 1300$^{\circ}C$ and 12 minutes. From these weight losses showing devolatilization and reduction of EAF dust, the treatment time of EAF dust inside.

• Journal of the Korean Ceramic Society
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• v.53 no.1
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• pp.116-121
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• 2016

The amount of carbon dioxide ($CO_2$) released while producing building materials is substantial and has been targeted as a leading contributor to global climate change. One of the most typical methods of reducing $CO_2$ in building materials is the addition of slag and fly ash, like pozzolan material another method is to reduce $CO_2$ production by developing carbon negative cement. MgO-based cement from the low-temperature calcination of magnesite required less energy and emitted less $CO_2$ than the manufacturing of Portland cements. It is also believed that adding reactive MgO to Portland-pozzolan cements can improve their performance and also increase their capacity to absorb atmospheric $CO_2$. In this study, basic research on magnesia cement using $MgCO_3$ and magnesium silicate ore (serpentine) as the main starting materials, as well as blast furnace slag for the mineral admixture, was carried out for industrial waste material recycling. In order to increase the overall hydration activity, $MgCl_2$ was also added. In the case of the addition of $MgCl_2$as accelerating admixture, there was a promoting effect on the compressive strength. This was found to be due to the production of needle-like dense Mg-Cl hydrates. Mgnesia cement has a high viscosity due to its high specific surface area therefore, when the PC-based dispersing agent was added at a level of more than 1.0%, it had the effect of improving fluidity. In particular, the addition of $MgCl_2$ in magnesia cement using $MgCO_3$and magnesium silicate ore (serpentine) as main starting materials led to a lower expansion ratio and an increase in the freeze-thaw resistance finally, the addition of $MgCl_2$ as accelerating admixture led to good overall durability.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.11a
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• pp.65-66
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• 2012

The cement used in the construction industry of the manufacturing process, large amounts of the greenhouse gas, CO₂ and is currently being studied for cement substitutes that reduce greenhouse gas issue. Therefore, the this study as a replacement for cement industrial by-product of blast furnace slag, red mud, silica fume and alkali-activator, using only inorganic composites without high-temperature calcination process were manufactured. The waste gypsum board micro powder added to compensate for the shrinkage cracks, the compressive strength and flow, and length change characteristics were investigated. Consequently, The setting time was shortened as GB added And liquidity was reduced. GB 2%, 7 days curing the added strength of specimens was the highest. Came out, and change the length of the Plain least.

• Resources Recycling
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• v.24 no.5
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• pp.3-14
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• 2015

This study investigated that status of domestic and international furnace desulfurization and desulfurization characteristics of limestone for fluidized bed use depending on the technology for CFBC one of the CCPs. Limestone-based desulfurizing agent is one of the superior elements which are optimal at around $850-950^{\circ}C$ on high temperature desulfurization. And effectiveness of desulfurization process can be determined by the desulfurization experiment method such as diffusion reaction of the diaphragm of the absorber surface, the size of the particles, the pores of the quantity, size and structure. And, desulfurization efficiency depending on geological and crystallographic properties and calcination process of limestone needs additional research in the future.

• Korean Journal of Materials Research
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• v.23 no.1
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• pp.67-71
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• 2013

Porous $Al_2O_3$ dispersed with nano-sized Cu was fabricated by freeze-drying process and solution chemistry method using Cu-nitrate. To prepare porous $Al_2O_3$, camphene was used as the sublimable vehicle. Camphene slurries with $Al_2O_3$ content of 10 vol% were prepared by milling at $50^{\circ}C$ with a small amount of oligomeric polyester dispersant. Freezing of the slurry was done in a Teflon cylinder attached to a copper bottom plate cooled to $-25^{\circ}C$ while unidirectionally controlling the growth direction of the camphene. Pores were subsequently generated by sublimation of the camphene during drying in air for 48 h. The green body was sintered in a furnace at $1400^{\circ}C$ for 1 h. Cu particles were dispersed in porous $Al_2O_3$ by calcination and hydrogen reduction of Cu-nitrate. The sintered samples showed large pores with sizes of about $150{\mu}m$; these pores were aligned parallel to the camphene growth direction. Also, the internal walls of the large pores had relatively small pores due to the traces of camphene left between the concentrated $Al_2O_3$ particles on the internal wall. EDS analysis revealed that the Cu particles were mainly dispersed on the surfaces of the large pores. These results strongly suggest that porous $Al_2O_3$ with Cu dispersion can be successfully fabricated by freeze-drying and solution chemistry routes.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.1
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• pp.1-8
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• 2023

In this study, to reduce CO₂ emission in the cement manufacturing process, we evaluated the limestone that is used as a raw material for cement, substituted with steel slag by the various substituted levels. Based on the chemical composition of each raw materials including limestone, and blast furnace slow cooling slag, converter slag, and KR slag as an alternative raw material, we simulated the optimal cement raw mixture by the substitution levels of limestone. Test results indicated that the steel slags contain a certain level of CaO that can be used as alternative decarbonated raw materials, and it has enough to partially reduce the amount of limestonem. And we estimated the maximum usable levels of each raw material. In particular, it was confirmed that by using a mixture of these raw materials rather than using them one by one, the effect of reducing limestone was increased and CO₂ emission from the cement manufacturing process could be reduced.