• The Journal of the Petrological Society of Korea
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• v.26 no.2
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• pp.143-152
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• 2017

As weathering processes, micro-cavities are formed on the surface of rocks, and in particular, the porous structure is increased in feldspar. Adsorption and antibacterial tests were carried out to clarify the environmental function of porous feldspar porphyry. Almost all the heavy metals were adsorbed in the feldspar filter and the adsorption rate could be controlled by changing the filter length. The shake flask method of fabric coated with 5% and 7% feldspar powder showed very high antibacterial activity of 98% and 99.9%, respectively. The cation exchange capacity at a particle size of $10{\mu}m$ was 114.63 meq/100g probably due to the porous structure. The potential value of porous feldspar porphyry as a resource is sufficient based on the results of the experiment.

• Journal of the Korean Geosynthetics Society
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• v.20 no.4
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• pp.33-41
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• 2021

Feldspar, along with Quartz, are the most frequently produced minerals in Korea; however, the potential value is estimated to be significantly low because of the scarce research on the development and application of material properties, except for their limited use in manufacturing minerals, glass, and paints. In this study, we analyzed the eco-friendly material and reactivity improvement characteristics of weathered feldspar through activation technique. The joint structural features observed on the surface of the weathered feldspar show that the joint arrangements are irregularly distributed, and the cavities are interconnected. Due to the irregularly connected cavities on the surface of weathered feldspar, the reaction area of the weathered feldspar is increased; hence the weathered feldspar is considered as a highly reactive pozzolan material when combined with cement. As a result of applying the thermal, mechanical, and chemical activation techniques to improve the functionality of the weathered feldspar, the cation exchange capacity, density, and uniaxial compression strength characteristics were improved. It is considered that weathered feldspar by these porous characteristics can be used as an eco-friendly construction material with excellent physical and chemical properties.

• Journal of the Korean Ceramic Society
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• v.35 no.6
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• pp.575-582
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• 1998

Sutiability of Jungsan clay shale dolomite sludge Anyang feldspar and alumina as raw materials for light-weight porous ceramics was examined. In order to find optimum manufacturing conditions compositions heating temperatuers and heating times were varied and their effects on physical properties were measured and bloating mechanism was investigated. Jungsan clay seems suitable as raw material to make the light-weight constructional materials with 5wt% of ANyang feldspar and alumina added in calcined clay (800$^{\circ}C$) having bulk density of 0.45g/cm3 water absorption of 1.34% and compressive strength of 85kg/cm2 rapid-heated at 1200$^{\circ}C$ for 30min. It is suggested that bloating mechanism depends on the difference of tem-peratures between the inside and outside in specimen the remained gases in interstices can bloat by the li-quid phase of surface with high viscosity and gas pressure at elevated temperature.

• Journal of the Korean Geosynthetics Society
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• v.20 no.4
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• pp.1-7
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• 2021

In response to the carbon emission reduction trends and the depletion of natural sand caused by the use of cement in construction works, graphene oxide and porous feldspar were applied as countermeasures in this study. By using (3-aminopropyl)trimethoxysilane-functionalized graphene oxide with enhanced bond characteristics, a concrete specimen was prepared with 5% less cement content than that in a standard mortar mix, and the compressive strengths of the specimens were examined. The compressive strengths of the specimen with (3-aminopropyl)trimethoxysilane-functionalized graphene oxide and porous feldspar and the specimen with standard mixing were 26MPa and 28MPa, respectively, showing only a small difference. In addition, both specimens met the compressive strength of cement mortar required for geotechnical structures. It is believed that a reasonable level of compressive strength was maintained in spite of the lower cement content because the high content of pozzolans, namely SiO₂ and Al₂O₃, in the porous feldspar enhanced the reactions with Ca(OH)₂ during hydration, the nano-sized graphene surface acted as a reactive surface for the hydration products to react actively, and the strong covalent bonding of the carboxyl functional group increased the bonding strength of the hydration products.

• Economic and Environmental Geology
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• v.50 no.2
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• pp.159-170
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• 2017

The temporal and spatial temperature distribution of the heat storage mortar made of porous feldspar was measured and the thermal properties and electricity consumption were analyzed. For the experiment, two real size chambers (control model and test model) with hot water pipes were constructed. Two large scale models with hot water pipes were constructed. The surface temperature change of the heat storage layer was remotely monitored during the heating and cooling process using infrared thermal imaging camera and temperature sensor. The temperature increased from $20^{\circ}C$ to $30^{\circ}C$ under the heating condition. The temperature of the heat storage layer of the test model was $2.0-3.5^{\circ}C$ higher than the control model and the time to reach the target temperature was shortened. As the distance from the hot water pipe increased, the temperature gap increased from $4.0^{\circ}C$ to $4.8^{\circ}C$. The power consumed until the surface temperature of the heat storage layer reached $30^{\circ}C$ was 2.2 times that of the control model. From the heating experiment, the stepwise temperature and electricity consumption were calculated, and the electricity consumption of the heat storage layer of the test model was reduced by 66%. In the cooling experiment, the surface temperature of the heat storage layer of the test model was maintained $2^{\circ}C$ higher than that of the control model. The heat storage effect of the porous feldspar mortar was confirmed by the temperature experiment. With considering that the time to reheat the heat storage layer is extended, the energy efficiency will be increased.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.5
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• pp.377-382
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• 2007

Porous mineral coating have been fabricated and applied for basic research on their slow release action to a fertilizer. Feldspar was selected as raw mineral for the coating and two different particle sizes of powder were prepared. Slow-release action was estimated by using a potassium sulfate fertilizer. Spherical pellets were prepared with a pan-type pelletizer and then screened into sizes ranging 1.4 to 2.35mm. While the fertilizer pellets were rotated in the pelletizer again, the feldspar powder and 0.5% polyvinyl alcohol solution were simultaneously sprayed on the pellets. The fertilizer pellets coated with feldspar powder were fabricated. The pellets were heated to increase their strength and screened to sort by coating thickness. Potassium releasing tests were conducted for 40 days and the performance for slow-release action was estimated as functions of the heating temperature, coating thickness and raw mineral powder size. The Burst effect caused high initial releasing rate. Releasing kinetics was proportional to concentration of potassium in pellets. The pellet that was fabricated with $27.4{\mu}m$-sized feldspar and heated at $1050^{\circ}C$ showed a releasing rate of 43% on the 40th day.

• Economic and Environmental Geology
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• v.56 no.1
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• pp.55-63
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• 2023

Variations in geochemical and mineralogical properties of the ferromanganese(Fe-Mn) crust reflect environmental changes. In the present study, geochemical and mineralogical analyses, including micro X-ray fluorescence and X-ray diffraction, were utilized to reconstruct the paleo-ocean environment of western Pacific Magellan seamount cluster. Samples of the Fe-Mn crust were collected using an epibenthic sledge from the open seamount XX (151° 51.12' 7.2" E and 16° 8.16' 9.6" N, 1557 meters below sea level) in the Western Pacific Magellan Seamount. According to the structure and phosphating status, the Fe-Mn crust of the OSM-XX can be divided into the following: phosphatizated (L4-L5), massive non-phosphatizated (L3), and porous non-phosphatizated (L1-L2) portions. All ferromanganese layers contain vernadite, and owing to the presence of carbonate fluorapatite (CFA), the phosphatizated portion (L4-L5) is rich in Ca and P. The massive non-phosphatizated section (L3) contains high Mn, Ni, and Co, whereas the porous non-phosphatizated portion (L1-L2), which comprises detrital quartz and feldspar, is rich in Fe. Variations in properties of the Fe-Mn crust from the OSM-XX reflect changes in the nearby marine environment. The formation of this crust started at approximately 51.87 Ma, and precipitation of the CFA during the global phosphatization event that occurred at approximately 36-32 Ma highlights an elevated sea level and low temperature during the associated period. The high Mn, Ni, and Co concentrations and elevated Mn/Fe ratios of samples from the massive phosphatizated portion indicate that the oxygen minimum zone (OMZ) was enhanced, and reducing conditions prevailed during the crust formation. The high Fe and low Mn/Fe ratios in the porous portion indicate a weak OMZ and dominantly oxidizing conditions. These data reflect environmental changes following the end of the Mi-1 glacial period in the Miocene-Oligocene boundary. Subsequently, Mn/Fe and Co/Mn ratios increased slightly in the outermost part of Fe-Mn crust because of the enhanced bottom current and OMZ associated with the continued cooling from approximately 9 Ma. However, the reduced carbonate dissolution rate in the Pacific Ocean from approximately 6 Ma decreased the growth rate of the Fe-Mn crust.