• Magazine of RCR
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• v.7 no.3
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• pp.13-17
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• 2012

• Magazine of RCR
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• v.6 no.2
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• pp.30-33
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• 2011

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.3
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• pp.167-173
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• 2018

In general, calcium is required for the reaction of blast furnace slag fine powder and fly ash. The by-products generated during the process of producing recycled aggregates have different calcium contents depending on the crushing stage and the possibility of using the process by-product as a concrete mixture is also different. In this study, the effect of the calcium content of the by-products on the compressive strength was investigated and the block was fabricated by using this. To utilize the by-products as an admixture, the calcium content was analyzed and the bending strength and surface temperature were measured according to the shape of the water storage block. As a result of this study, the possibility of making a block using recycled aggregate by-products was verified and arch type block was constructed to secure storage capacity and bending strength. Also, the surface temperature of the water storage block was reduced by $9^{\circ}C$ or more than that of the general permeable block.

• Journal of the Mineralogical Society of Korea
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• v.22 no.4
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• pp.353-358
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• 2009

The ability of natural abrasives which were recovered from CRT glass polishing process was evaluated. Comparing the center line average roughness values of a glass polished with new pumice (Ra = $0.039{\mu}m$) and with new garnet (Ra = $0.031{\mu}m$), the glass surface polished with the recycled pumice and the garnet had less pits on the surface with smaller Ra values (Ra = $0.025{\mu}m$ for recycled pumice and Ra = 0.029 for recycled garnet). Recycled rouge contains amorphous glass fragments so that it should be used as a cement replacement rather than recycle into an abrasive. Nnatural abrasives, pumice and garnet powder, which are used in CRT glass polishing process can be recycled into abrasives so that it can help to minimize costs and environmental impact from the production of abrasives and the disposal of waste sludge.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.3
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• pp.287-294
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• 2021

In this study, tests were performed to analyze the feasibility of using the ground stabilizer from recycled resources such as blast furnace slag powder as filling material of prebored piles. For this, specimens were prepared by applying 70% and 83% of the general water/binder ratio of the filling material of prebored piles. And compression test, model test, and shaking table test were performed to determine the compressive strength, skin friction on the surface between prebored pile and filling material, and seismic performance of ground stabilizer. As a result of the tests, the compressive strength exceeded the relevant domestic standards, and the skin friction was equivalent to that of ordinary portland cement. In addition, the amount of vertical and horizontal displacement caused by earthquakes was found to be much smaller than the domestic standard. Therefore, when considering the test results comprehensively, it is judged that the feasibility of using a ground stabilizer from recycled resources as filling material for prebored pile is sufficient.

• Journal of Powder Materials
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• v.22 no.4
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• pp.278-282
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• 2015

The GaN-powder scrap generated in the manufacturing process of LED contains significant amounts of gallium. This waste can be an important resource for gallium through recycling of scraps. In the present study, the influence of annealing temperatures on the structural properties of GaN powder was investigated when the waste was recycled through the mechanochemical oxidation process. The annealing temperature varied from $200^{\circ}C$ to $1100^{\circ}C$ and the changes in crystal structure and microstructure were studied. The annealed powder was characterized using various analytical tools such as TGA, XRD, SEM, and XRF. The results indicate that GaN structure was fully changed to $Ga_2O_3$ structure when annealed above $900^{\circ}C$ for 2 h. And, as the annealing temperature increased, crystallinity and particle size were enhanced. The increase in particle size of gallium oxide was possibly promoted by powder-sintering which merged particles to larger than 50 nm.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.2
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• pp.125-134
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• 2005

Waste concrete powder was used to remove fluoride ions in highly concentrated fluoride wastewater. 92.6% of fluoride in 100 mg F/L wastewater was removed by 1% dose of the cement paste powder that represents characteristics of waste concrete powder, whereas the removal efficiencies of raw cement and lime were 47.3% and 96.4%, respectively. The cement paste powder was competitive to lime, common fluoride removal agent. Various Ca-bearing hydrates such as portlandite, calcium silicate hydrate, and ettringite in cement paste slurry can remove fluoride by precipitating $CaF_2$ and absorbing $F^-$ ions. In the experiments using both cement paste and lime, 50~67% of lime can be substituted by cement paste to satisfy fluoride effluent limitation of 15 mg/L. Since cement paste has higher acid neutralization capacity than lime, it can be recycled to neutralize more acid and to remove more fluoride. Therefore waste concrete powder can be more economical and viable alternative for lime in fluoride wastewater treatment.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.1
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• pp.26-32
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• 2021

Powder type sericite has been actively researched in the area of chemistry and mineralogy in terms of waste recycling. It is a material that can be obtained relatively inexpensively with a low thermal conductivity like general mica, so in order to improve the thermal conductivity of the mortar, powder type sericite was used in this work. Compressive strengths of mortar before and after high temperature exposure were compared and evaluated to determine the fire resistance of mortar with powder type sericite. According to the experimental results, it was found that the compressive strength decreased when powder type sericite was replaced with cement, but the decrease in compressive strength with the increasing amount of powder type sericite was insignificant. When powder type sericite was incorporated, the thermal conductivity decreased, and the residual strengths of the mortar specimens which were heat treated at 600℃, 900℃, and 1,200℃ were higher than that of plain mortar. From the comprehensive evaluation of the experimental results, it can be concluded that the powder type sericite has the potential to be used as a refractory material for cement composites.

• Food Science and Preservation
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• v.16 no.6
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• pp.843-848
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• 2009

Green peppers were dried using maltodextrin and recycled dehydration liquid as dehydrating agents, and the quality of dried green pepper powders was compared with that of freeze-dried and hot air-dried samples in terms of moisture content, color, antioxidant activity, capsaicinoid level, and sensory acceptability. The moisture content of maltodextrin-treatedgreen pepper powder was higher than that of samples prepared using recycled dehydration liquid. The lightness (L) value rose with increasing concentrations of maltodextrin powder or liquid. The antioxidant activities of pepper powders prepared using the molecular press dehydration method were similar to that of alpha-tocopherol, and better than that offreeze-dried or hot air-dried samples. Capsaicinoid levels fell with increasing concentrations of maltodextrin powder and liquid. The sensory evaluation data on green pepper powders prepared using the molecular press dehydration method were better than those obtained when freeze-dried and hot air-dried samples were evaluated. These results indicate that drying of green pepper powders using maltodextrin and recycled dehydration liquid as dehydrating agents is very efficient.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.785-788
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• 2008

Ceramics manufactures in the nation produced more than 5,000 tons of waste pottery a year increasing industrial waste quantity. However, Almost researches were made to reduce environmental pollution and recycle waste ware. It is needed that they are used as recycled materials in order to prevent environmental pollution and gain economic profits. Therefore, the purpose of this study is to present the method of utilizing the recycled cements that are obtained from waste pottery. The test results that replacement of waste pottery powder by cement admixture at the level 10% had effect on the stripping strength(compressive strength). Also, When GBFS and WP used by cement admixture, WP is better than GBFS.