• Preventive Nutrition and Food Science
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• v.12 no.4
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• pp.217-221
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• 2007

Within the elderly population, the use of calcium supplements and the intake of calcium from food are on the rise in order to maintain health. Calcium is absorbed as an ion in vivo, leading to speculation that absorption efficiency is affected by the solubility of the calcium consumed. In our study, the bioavailability of two types of calcium supplements with different solubilities was evaluated. Experimental animals were fed water-soluble or insoluble calcium supplements for 6 weeks. We found that blood alkali phosphatase activity, osteocalcin content, and urine crosslinks values were not different between the groups. Similarly, the degree of apparent calcium absorption between the two calcium supplements was not significantly different. The bone mineral density and bone mineral content of the femur and the tibia increased in the group that consumed insoluble calcium compared with those of the water-soluble calcium supplemented group. However, when considering body weight, the bone mineral density value for all areas, including the spine, was significantly higher in the group that consumed the water-soluble calcium supplement.

• Journal of the Korean Ceramic Society
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• v.51 no.2
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• pp.64-71
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• 2014

Accelerated carbonation is a technique that can be used as a CCS technology for $CO_2$ sequestration of approximately 5~20% in a stable solid through the precipitation of carbonate. An alkaline inorganic waste material such as ash, slag, and cement paste are generated from incinerators, accelerated carbonation offers the advantage of lower transport and processing costs at the same generation location of waste and $CO_2$. In this study, we evaluated an amount of $CO_2$ sequestration in various types of inorganic alkaline waste processed by means of accelerated carbonation. A quantitative evaluation of $CO_2$ real sequestration based on a TG/DTA analysis, the maximum 118.88 $g/kg_{-waste}$ of $CO_2$ in paper sludge fly ash, the maximum 134.46 $g/kg_{-waste}$ of $CO_2$ in municipal solid waste incinerator bottom ash, the maximum 9.72 $g/kg_{-waste}$ of $CO_2$ in industrial solid waste incinerator fly ash, and the maximum $18.19g/kg_{-waste}$ of $CO_2$ in waste cement paste.

• Nutritional Sciences
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• v.9 no.1
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• pp.42-47
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• 2006

It has been reported that taking a proper amount of calcium and vitamin D helps to increase bone mineral density (BMD) and is effective in decreasing the risk of osteoporosis. This study investigated the supplementary effects of calcium and vitamin D on postmenopausal women who had osteoporosis and used calcium and vitamin D supplements. The study subjects consisted of osteoporotic postmenopausal women who were recruited from the Department of Orthopedics in a university-affiliated hospital. Sixty-seven study subjects were orally administrated 1,000 mg of calcium (calcium carbonate) and 2.5 mg of active vitamin D (1-$\alpha$ hydroxyvitamin D) (cholecalciferol 250 IU) twice a day for a year and a half. BMD and biochemical markers were evaluated and repeated every six months. One year after the intervention test, the bone mineral density of the lumbar spine was significantly increased as compared to the baseline. Six months after supplement administration, the level of serum alkaline phosphatase began to decrease, and afterwards a significant difference was maintained Concentration of 1, 25-dihydroxy-vitamin D at 1.5 years was higher than that of the baseline. In comparison with that of the baseline, the level of urinary hydroxyproline in the study subjects over six months was significantly decreased This study continued that effects such as BMD improvement and changes in biochemical markers appeared at least one year after administration of supplements.

• Journal of Soil and Groundwater Environment
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• v.26 no.3
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• pp.14-24
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• 2021

Aquifer thermal energy storage (ATES) system uses groundwater thermal energy for cooling and heating of buildings, and it is also often utilized to provide warm water to crops and plants for the purpose of enhancing agricultural yields. This study investigated the potential influences of a ATES system on the geochemical properties of groundwater by simulating the variation of hydrochemistry and saturation index of groundwater during ATES operation. The test bed was installed at an agricultural field, which is mainly composed of an groundwater-rich alluvial plain. The simulation results showed no significant precipitation of mineral phases such as manganese-iron oxide, carbonate and sulfate around the ATES test bed, as well as no debasement of other important water quality parameters. The implementation of ATES system in the study area was appropriate and effective for utilizing the thermal energy of groundwater for agricultural use.

• Geosciences Journal
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• v.22 no.6
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• pp.921-938
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• 2018

The Motzfeldt intrusions in the Gardar Province, southern Greenland, split into syenitic plutonic and hypabyssal rocks, in which the latter include ring dykes and sheet intrusions. Sheet intrusions, considered as the source for rare earth elements (REE) and high field strength elements (HFSE), comprise sheets of peralkaline microsyenite (SPM), syenitic pegmatite (SP), and peralkaline microsyenite (PM). SP exhibits extremely high concentrations of REE and HFSE, which are positively correlated with increasing alkalinity from early towards late intrusion, caused by magmatic processes. In contrast, some of the SPM and PM are also significantly enriched in REE and HFSE, caused by post-magmatic fluids. The REE- and HFSE-rich phases in SP consist mainly of zircon and allanite with smaller amounts of pyrochlore in pseudomorph from the inferred eudialyte, whereas some of the PM and SPM consist of pyrochlore, REE-carbonate, and zircon in the matrix. The zircon grains in the Motzfeldt Sø Formation (MSF) syenite occur in interstitial spaces, exhibiting an association with magnetite and a bipyramidal form in texture. They are characterized by a highly fractured and embayed rim. Zircons from PM and SP are clearly enriched in Fe, Al, Ca, Na, Y, P, Hf, Y, P, Nb, Ta, and REE, and are depleted in Zr and Si in comparison with magmatic zircon. They also show a clear trend of higher LREE/HREE and $Eu/Eu^{\star}$ ratios, and lower $Ce/Ce^{\star}$ ratios, which define them as typical hydrothermal zircons. In contrast, zircons from the MSF syenite show a relatively lower LREE/HREE ratio and Eu and Ce anomalies of a similar magnitude compared with those from SP and PM. The occurrence and mineral composition of the zircon suggest that post-magmatic fluids have played an important role in the remobilization of REE and HFSE as well as the primary concentration of REE and HFSE, caused by magmatic processes.

• The Korean Journal of Quaternary Research
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• v.21 no.2
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• pp.69-73
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• 2007

Inorganic geochemical and mineralogical analyses from the trench sediments of the Hwayang wetland were carried out to verify the wet/dry conditions during 6000 - 5000 yr BP and abnormal event of 6300 yr BP of Korean west coast. Lithostratigraphy, mineralogy and major element concentrations of the sediments of the trench indicate that during 6000 - 5000 yr BP, a wet/dry conditions might be repeated at an interval of 200 years. Carbonate minerals precipitated with the decrease of water depth in the lake or wetland after about 6000 yr BP. On the other hand, the sediments coarser in mean grain size and larger in standard deviation were corresponded with periods of 6300 yr BP and 6230 yr BP. Especially, such a feature of grain size distribution of 6300 yr BP appears in other wetlands situated in the west coast, e.g., Hwangsan wetland and Cheollipo coastal wetland. During the period, the coarse sediments seem to have been delivered by a high energy like storming.

• Journal of the Mineralogical Society of Korea
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• v.23 no.4
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• pp.281-295
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• 2010

This paper deals with magnetic susceptibility, mineralogy, soil properties (pH, EC, CEC, loss on ignition), iron and manganese oxides, the content and partitioning of heavy metals (As, Cd, Cr, Cu, Ni, Pb, Zn), and their mutual relationship in the soil samples of an unpolluted, abandoned mine area, and industrial complex area. The various minerals derived from weathered bedrock were identified by X-ray diffraction in the unpolluted soil samples, except for the magnetic minerals. XRD analysis also revealed the existence of hematite and magnetite related to mine tailings and waste rocks in the abandoned mine area samples. The industrial complex area samples had carbonate minerals, such as calcite and dolomite, that might be due to anthropogenic deposition. The sum of the reducible, oxidizable, and residual fractions was over 80% for the abandoned mine area samples and over 50% for the industrial complex area samples using the sequential extraction method. The industrial complex area samples had a relatively high carbonate fraction that was associated with carbonate minerals. The content of aqua regia-extractable Fe, Mn, As, and Zn had a high positive correlation with the content of the dithionite-citrate-bicarbonate (DCB)-extractable method related to Fe/Mn oxide phases. The 54% and 58% of aqua regia-extractable Fe and As content, respectively, acted together with the concentrations of the DCB-extractable phases. Magnetic susceptibility values of total samples ranged from 0.005 to $2.131{\times}10^{-6}m^3kg^{-1}$. The samples including iron oxide minerals, such as hematite and magnetite, had a high magnetic susceptibility. The magnetic susceptibility showed a significant correlation with the heavy metals, Cd (r=0.544, p<0.05), Cr (r=0.714, p<0.01), Ni (r=0.645, p<0.05), Pb (r=0.703, p<0.01), and Zn (r=0.496, p<0.01), as well as Fe (r=0.608, p<0.01) and Mn (r=0.615, p<0.01). The aqua regia-extractable Fe and Mn content had a significant positive correlation with Cd, Cr, Cu, Ni, and Zn. However, the DCB-extractable Fe and Mn content had a significant positive correlation with As and Ni, indicating that the heavy metals were associated with Fe and Mn oxide minerals.

• The Journal of the Petrological Society of Korea
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• v.11 no.2
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• pp.90-102
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• 2002

The studied Fe-REE ore consists of magnetite, ankerite, siderite, magnesite and strontianite as the major constituent, and monazite, columbite, fergusonite, apatite, aegirine-augite, Na-amphibole, pyrite, chalcopyrite, sphalerite, molybdenite and barite as accessaries. Wall rock of ore deposits is replaced to fenite due to Na-metasomatism and mainly consists of sugary albite and Na-amphibole. Monazite $Ce_{0.49}La_{0.31}Pr_{0.14}Nd_{0.03}Gd_{0.03})PO_4$ is the main mineral for REE deposit and shows myrmekitic intergrowth with strontianite $Ca_{0.02-0.16}Sr_{0.84-0.98}CO_3$ and is corroded by carbonate minerals. Mineral forming sequence can be divided into early and late periods by the development of microfractures. The early period minerals such as magnetite, ankerite, magnesite, monazite and apatite show well developed networks of microfractures due to cataclastic deformation caused by enriched $CO_2$ gas in melts during emplacement. The late minerals of columbite, fergusonite, siderite molybdenite, chalcopyrite and sphalerite formed after the brecciation event and have little micro-fractures. Ankerite, magnesite, monazite, strontianite, barite and pyrite seem to be formed continuously from the ealy to the late period since they show textures both with well developed fractures and also with little fractures. Mineral chemistry, mineral assemblages such as various carbonate minerals, magnetite, REE minerals of monazite and fergusonite, Sr mineral of strontianite, and Nb minerals of columbite, myrmekitic texture of monazite and ankerite, and well developed fenite along ore deposits observed from this studied area strongly indicate that this Hongcheon Fe-REE ore deposits are formed from carbonatitic melt and its rock type is late differentiated Fe-carbonatite or ankerite-carbonatite.

• Resources Recycling
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• v.31 no.3
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• pp.40-52
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• 2022

This study analyzed the amount of carbon dioxide reduction and economic benefits of detailed processes of CO₂ 6,000 tons plant facilities with mineral carbonation technology using carbon dioxide and coal materials emitted from domestic circulating fluidized bed combustion power plants. Coal ash reacted with carbon dioxide through carbon mineralization facilities is produced as a complex carbonate and used as a construction material, accompanied by a greenhouse gas reduction. In addition, it is possible to generate profits from the sales of complex carbonates and carbon credits produced in the process. The actual carbon dioxide reduction per ton of complex carbonate production was calculated as 45.8 kgCO₂eq, and the annual carbon dioxide reduction was calculated as 805.3 tonCO₂, and the benefit-cost ratio (B/C Ratio) is 1.04, the internal rate return (IRR) is 10.65 % and the net present value (NPV) is KRW 24,713,465 won, which is considered economical. Carbon mineralization technology is one of the best solutions to reduce carbon dioxide considering future carbon dioxide reduction and economic potential.

• Resources Recycling
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• v.24 no.4
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• pp.22-31
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• 2015

From results obtained by adjusting experimental variables based on the kinetic, the nucleation rate for formation of precipitated calcium carbonate (PCC) was investigated. Formation behavior of PCC was investigated for various concentrations of NaOH solution and $Na_2CO_3$ addition methods in the $Ca(OH)_2$ slurry. The range of nucleation rate was investigated for dissolution rates of major ion concentrations, $Ca^{2+}$ and $CO{_3}^{2-}$. In case of high concentration of major ions, vaterite and calcite were synthesized. The high nucleation rate was achieved for lower either $Ca^{2+}$ or $CO{_3}^{2-}$ ion concentration, calcite was mainly synthesized and when concentration of major ions was low, aragonite was synthesized. Furthermore, the formation of calcite was decreased with increasing concentration of NaOH. homogeneous aragonite could be obtained by addition 5 M NaOH. Therefore, in this study, specific shape of polymorphs could be prepared through controlling supersaturation.