• Asian-Australasian Journal of Animal Sciences
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• v.25 no.6
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• pp.839-844
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• 2012

This experiment was conducted to evaluate the effects of single or multi-particle size limestone on the egg shell quality, egg production, egg quality and feed intake in laying hens. A total of 280 laying hens (ISA brown) were used in this 10-wk trial. Laying hens were randomly assigned to 4 treatments with 14 replications per treatment and 5 adjacent cages as a replication (hens were caged individually). The experimental treatments were: i) L, basal diet+10% large particle limestone; ii) LS1, basal diet+8% large particle limestone+2% small particle limestone; iii) LS2, basal diet+6% large particle limestone+4% small particle limestone; iv) S, basal diet+10% small particle limestone. The egg production was unaffected by dietary treatments. The egg weight in S treatment was lighter than other treatments (p<0.05). The egg specific gravity in S treatment was lower than other treatments (p<0.05). The eggshell strength and eggshell thickness in S treatment were decreased when compared with other dietary treatments (p<0.05). The laying hens in LS1 and LS2 treatment had a higher average feed intake than the other two treatments (p<0.05). Collectively，the dietary multi-particle size limestone supplementation could be as efficient as large particle size limestone.

• Journal of The Geomorphological Association of Korea
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• v.26 no.1
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• pp.41-57
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• 2019

The grain size characteristics of river sediments and the characteristics of bedrock were investigated for the 24km section of the Dong River upstream of the Han River. The bedrock of the study area is various limestone belonging to the Paleozoic Choseon limestone group, and Mesozoic sandstone and conglomerate occur in some areas. Most of the river channel is made of limestone, and most of the river bottom is covered with fluvial sediments. More than 70% of these sediments are sandstone and conglomerate, rather than limestone which forms the basis of the valley. Sediment particles seem to have been supplied upstream of the study area rather supplied from the slope near of the channel. It is difficult to find the statistically significant difference in the shape of the sediment particles of limestones and non-limestones. However, limestones has platy forms rather than block forms, it can be assumed that the limestone was supplied from the surrounding valley wall and transported over a short distance. The particle sizes of DG1~DG2(the upstream section) are decreasing in the downstream direction. However, at DG3, which is a tributary, Jijangcheon, confluence particle size increases and at DG4 particle size increases more. In the case of DG4, it may be influenced by the influx of tributaries, but it also can be supposed as the impact of the large flood in 2002. In the downstream parts(DG5~DG7), the particle size decreases exponentially with distance. The rebound strength of stream sediments and bedrock was measured by using Schmidt hammer. Limestone showed lower rebound strength than non-limestone. According to the results of the sediment and bedrock, it can be seen that the sandstone and conglomerate with high rebound values pass through valley with the relatively low strength limestone. The sediments of limestone were decreased in grain size more rapidly than those of limestone sediments.

• Clean Technology
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• v.7 no.1
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• pp.81-88
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• 2001

Limestone has been used as absorbent in the FGD(Flue Gas Desulfurization) system, the DeSOx system of thermal power plant. This study investigated the desulfurization characteristics of the two different limestones, 325mesh and 200mesh particle size. Experimental analysis showed that the dissolving rate of limestone became much slower as the particle size increased. But the desulfurization efficiency depended on the L/G(liquid/gas) ratio and slurry pH regardless of the limestone particle size. The quality of gypsum produced in the FGD process increased as the limestone particle size or the slurry pH decreased. To reduce the cost of absorbent, the mixed limestone which were composed of 200 and 325mesh limestone with 5 different ratios were tested.

• Resources Recycling
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• v.24 no.6
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• pp.17-23
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• 2015

Flue gas desulfurization(FGD) is the technique to remove $SO_2$ gas from stack gases of coal-fired plants. Many researcher have studied to replace the desulfurizing agent because FGD systems use a lot of limestone and energy. In this study, we use the limestone sludge which is a by-product of steel industry in order to replace desulfurizing agent of FGD system by control the particle size of limestone sludge. And desulfurization performance test is implemented by investigating $SO_2$ gas removal properties upon the characteristic of the limestone sludge with various particle size.

• Journal of the Korean Ceramic Society
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• v.50 no.2
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• pp.149-156
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• 2013

This study examines the effects of limestone's factors on the fluidity of cement paste when of up to 15%. As the substitution ratio of limestone powder increases, the fluidity of the paste is also improved; however, it has no correlation to the $CaCO_3$ content of the limestone, fineness of the limestone, and fluidity of the pastes. Regardless of clay content of the limestone, it showed a similar mini-slump, so there was no correlation between the clay content and the fluidity of the paste. Also, the total organic carbon content of the limestone and the fluidity of the paste showed no correlation. Regardless of the limestone's grade or fineness, n value of powder gained by using the Rosin-Rammler distribution function showed that the fluidity of the paste increased as the n value reduced. It was also shown that particle size distribution of ordinary Portland cement with limestone powder had a major effect on the fluidity of the paste.

• Journal of Environmental Science International
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• v.15 no.6
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• pp.587-592
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• 2006

The advantage of CFBC(Circulating fluidized bed combustor) is that it can apply to various fuel sources including the lower rank fuel and remove SOx by means of direct supply of limestone to the combustor without additional desulfation facility. In this paper, we denote characteristics of fly and bed ash to reuse finer limestone usually abandoned(used spec[Coarse LS] 0.1mm under 25%, new spec[Fine LS] 0.1mm under 50%). According to the results, the chemical composition of fly ash was as follows; $SiO_2\;40.8%,\;Al_2O_3\;31.9%,\;CaO\;10.7%,\;K_2O\;4.46%$ in the case of coarse limestone and $SiO_2\;41.1%,\;Al_2O_3\;31.3%,\;CaO\;10.9%,\;K_2O\;4.66%$ in the case of fine limestone. The chemical composition of bed ash was as follows; $SiO_2\;54.2%,\;Al_2O_3\;33.1%,\;CaO\;1.56%,\;K_2O\;4.34%$ in the case of coarse limestone and $SiO_2\;53.8%,\;Al_2O_3\;32.6%,\;CaO\;2.21%,\;K_2O\;4.45%$ in the case of fine limestone. It showed that there was no significant change in chemical composition. And it is conformed that there was no significant change in particle size and shapes.

• Journal of the Korean institute of surface engineering
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• v.26 no.5
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• pp.255-262
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• 1993

Major parameters determining the extent of Ca utilization were investigated for their calcination/sulfation behavior of limestone in the AFBC(Atmospheric Fluidized Bed Combustion) environments. Three different particle sizes of Fredonia limestone were investigated in the lab-scale tubular reactor. The results of the calcination codnversion of limestone imply that thesd decomposition rate of CaCO3 into CaO is dependent on the amount of heat which limestone absorbed. Hg porosimeter measurement of calcined limestone illustrated that surface area and pore volume are increased with decreasing particle size. Raw Fredonia limestone and sequentially as well as simultaneously calcined/sulfated limestones were also examined using SEM. The SEM Studied showed that the surface of the calcined limestone particles is more diffusive nature than that of the parent calcite. However, the sulfur distribution pattern of simultaneously-treated particles and that of the se-quentially-treated one shows no difference.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.4
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• pp.429-436
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• 2004

Circulating fluidized bed combustion (hereafter CFBC) technology enables an efficient combustion for the materials with low heating values such as high ash coal and sludges. It also has desulfation function by adding limestone directly to combustor. The CFBC has been considered as one of the best processes for low grade coal containing with large contents of ash and sulfur. In this paper, in order to various tests were performed to find the optimum desulfation condition for CFBC using Korean Anthracite. We surveyed possible parameters and conducted desulfation efficiency test in D Thermal Power Plant. In addition, the result of some fundamental theoretical consideration was discussed with CFBC. Optimum limestone size could be considered to be 0.1-0.3mm irrespective of combustion temperature and Ca/S molar ratio variation. Desulfation efficiency increased as the molar ratio increased. Because desulfation process occurs at the surface at higher temperature, inner side of limestone can＇t be utilized. When surface area is not appropriate, some SO$_2$ emit without reaction. Optimum molar ratio should be decided after considering chemical and physical properties of limestone and coal thoroughly such as particle size, pore size and HGI. Commercial CFBC is operated at Ca/S 1.6. Combustor temperature 840-87$0^{\circ}C$ shows good desulfation efficiency.

• Journal of the Korean Ceramic Society
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• v.51 no.2
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• pp.127-131
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• 2014

Precipitated calcium carbonate(PCC) inorganic fillers for plastic offera higher replacement ratio with improved mechanical properties than any other inorganic fillers. Due to its secure economic feasibility, its fields of application areexpanding. For optimized PCC grain size and polymer replacement ratio, it is good to maintain at least $0.035{\mu}m$ grains and keep double the grain size of distance between particles, depending on the molecular weight and volume replacement rate of the polymer. PCC has unique characteristics, ie, with smaller grain size, dispersibility decreases, and if grain size is not homogenous, polymer cracking occurs. The maximum replacement ratio of PCC is approximately 30%, but in the range of 10 - 15% it produces the highest mechanical strength. When mixed with a biodegradable plastic like starch, it also improves initial environmental degradability.

• Resources Recycling
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• v.24 no.6
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• pp.38-44
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• 2015

It studies that effect of limestone of physicochemical characteristic on the performance of flue gas desulfurization (FGD) and application examination for technology of wet type FGD process and to utilize the limestone in Donghae-Samcheok. The experiment method was measured total neutralizing capability (TNC) using the lab scale experimental apparatus based on the HCl titration test. The results of TNC of limestone samples were more dependent on the physical characteristics including particle size rather than chemical compositions such as CaO content and particle size of limestone get smaller, TNC is increased.