• 한국재료학회지
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• 제26권5호
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• pp.266-270
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• 2016

Glass-ceramics were developed many years ago and have been applied in many fields such as electronics, chemistry, optics, etc. Much is already known about glass-ceramic technology, but many challenges in glass-ceramic research are still unresolved. Recently, large amounts of slag have steadily increased in the steel industry as by-products. To promote recycling of industrial waste, including steel industry slags, many studies have been performed on the fabrication of basalt-based high-strength glass-ceramics. In this study, we have fabricated such ceramics using various slags to replace high performance cast-basalt, which is currently imported. Glass-ceramic material was prepared in similar chemical compositions with commercial cast-basalt through a pyro process using slags and power plant by-product (Fe-Ni slag, converter slag, dephosphorization slag, Fly ash). The properties of the glass-ceramic material were characterized using DTA, XRD, and FE-SEM; measurements of compressive strength, Vicker's hardness, and abrasion were carefully performed. It is found that the prepared glass-ceramic material showed better performance than that of commercial cast-basalt.

• 한국세라믹학회지
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• 제53권1호
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• pp.63-67
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• 2016

Mineral hydrate is a new insulation material that compensates for the defects of existing materials. Mineral hydrate is made of inorganic ingredients; therefore, it is nonflammable. The porous structure of mineral hydrate makes the material lightweight and insulating. Mineral hydrate insulation and similar products have been studied and manufactured in Korea and abroad. However, these insulation materials need to improve in terms of strength. In this study, basalt fiber was used to enhance the strength. In order to observe the property changes, compressive strength, heat conductivity, and specific gravity were measured and XRD pattern analysis was performed. These tests confirmed that basalt fiber was effective at improving the strength and lowering the heat conductivity of mineral hydrate insulation.

• 동력기계공학회지
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• 제18권3호
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• pp.93-99
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• 2014

The purpose of this paper is to manufacture the non-sintered ceramic used lime and industrial waste. The used materials were basalt powder sludge, calcium hydroxide(Ca(OH)2) and additives such as calcium stearate and $TiO_2$. The mixing ratios between Ca(OH)2 and sludge were 5:5, 6:4 and 8:2, respectively. The ceramic forms were pressured by 100, 200 and 300 bar and cured in 14% CO2 for 12 days. The behaviors of compressive strength, specific gravity, water absorption and pH of ceramic form were investigated. The results were compressive strength of over 36 MPa, water absorption of over 8.8%, pH value of over 12.3. And these results satisfied GR F 4006 and 4031 standard.

• 한국화재소방학회논문지
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• 제30권2호
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• pp.35-42
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• 2016

막구조 건축물은 경량의 건축용 막재를 사용하므로 자유로운 곡면표현이 가능하고 시각적인 만족도가 높아 그 사용이 점차 확대되고 있다. 하지만 건축용 막재를 구성하는 직물이 화재에 취약하므로 용도에 적합하며 보다 높은 난연성능을 가지는 불연성 막재의 개발이 요구되고 있다. 따라서 본 연구에서는 단열성, 내열성, 불연성이 우수한 현무암섬유를 건축용 막재의 직포로 적용하고 PTFE 분산 수지를 함침 코팅하여 DSC/TGA 열분석, 강도특성, 방염 및 난연특성을 평가하였다. 또한, 일반적으로 사용되는 건축용 막재 중 성능이 가장 우수한 유리섬유 직포 막재와 난연특성을 비교하였으며 평가결과 현무암섬유 직포의 건축용 막재로서의 가능성을 확인할 수 있었다.

• 한국세라믹학회지
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• 제56권4호
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• pp.365-373
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• 2019

Pond ash is a mixture of mostly coarser fly ash and bottom ash. The recycling rate of pond ash is low because pond ash is mixed with seawater and deposited in ponds. The pond ash is also subjected to natural weathering over a period of time. In this study, we investigated whether pond ash can be used as a raw material of geopolymers, without any purification process or through a minimal purification process. In addition, we investigated whether synthetic basalt made by adding foaming agent to geopolymer or casting it into a mold can show the surface of the natural basalt as it is. The highest 7-day compressive strength in geopolymers from pond ash without purification process was 26 MPa. The highest 7-day compressive strength in geopolymers from pond ash with impurities removed through dry sieve analysis was found to improve to 80 MPa. On the other hand, synthetic basalt made with geopolymer was shown to be more advantageous aesthetically when produced by casting it in a silicone mold rather than by adding a foaming agent. Non-purified pond ash can be made into geopolymers having low strength. Pond ash purified by sieving can, without use of an aggregate, be made into geopolymer having high-strength. Also, it is possible to produce synthetic basalt with the same appearance as natural basalt and sufficient strength for commercialization. This process will contribute to the mass consumption and recycling of pond ash.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.1185-1186
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• 2013

• 한국세라믹학회지
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• 제17권3호
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• pp.151-157
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• 1980

Crystallization phenomena of glasses of fused natural basalt rocks were studied by DTA, X-ray phase analysis, electron microscopy, and other techniques. Crystallization was catalyzed by the addition of either chromite ore or $P_2O_5$, both up to 5 wt %. Various heat treatments were used, and their influences on controlling the microstructures and properties of the products were studied to develop high strength glass-ceramic material of the $CaO-Al_2O_3(Fe_2O_3)-MgO(FeO)-SiO_2$ system from the domestic basalts. Magnetite precipitates were found to be a nucleation initiator in every case of the crystallization. Diopside, anorthite, clinoenstatite and monticellite were identified as silicate crystalline phases contained in the crystallized products. The crystallite size was in the range of 0.1-2.5$\mu\textrm{m}$. The fine crystallites were approximately cubic, but large crystallites were either plate or needle shape. The thermal expansion coefficient, microhardness and modulus of rupture of glass-ceramics were ranged from 78.5 to 81.8$\times$10-7 cm/cm/$^{\circ}C$, from 820 to 930kg/$\textrm{mm}^2$, and from 1800 to 2800kg/$\textrm{cm}^2$, respectively.

• Composites Research
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• 제32권6호
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• pp.368-374
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• 2019

무기필러가 첨가된 현무암섬유 강화 에폭시 복합재료를 제조하여 그 특성을 평가하였다. 첨가된 무기필러는 각각 수산화마그네슘, 수산화알루미늄, 알루미나, 베마이트이며 이를 첨가제로한 에폭시 수지를 현무암섬유에 핸드레이업으로 함침시킨 후 hot pressing하여 수지 함침량이 30 wt%인 섬유복합재료를 제조하였다. LOI 평가 결과 BFRP의 LOI (28.9)는 에폭시 수지 (21.4)에 비해 향상된 것을 확인하였으며 무기필러가 첨가될 경우 그보다 더욱 향상되는 것을 확인하였다. 또한 무기필러가 첨가된 복합재료는 무기필러가 첨가되지 않은 복합재료에 비해 콘칼로리미터 시험에서 PHRR, THR, TSR 등이 감소하여 무기필러 첨가에 따른 난연 특성 향상을 확인하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 춘계학술대회 논문집
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• pp.957-958
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• 2012

• 한국재료학회지
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• 제27권5호
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• pp.281-288
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• 2017

In this study, Fe-Ni slag, converter slag and dephosphorization slag generated from the steel industry, and fly ash or bottom ash from a power plant, were mixed at an appropriate mixing ratio and melted in a melting furnace in a mass-production process for glass ceramics. Then, glass-ceramic products, having a basalt composition with $SiO_2$, $Al_2O_3$, CaO, MgO, and $Fe_2O_3$ components, were fabricated through casting and heat treatment process. Comparison was made of the samples before and after the modification of the process conditions. Glass-ceramic samples before and after the process modification were similar in chemical composition, but $Al_2O_3$ and $Na_2O$ contents were slightly higher in the samples before the modification. Before and after the process modification, it was confirmed that the sample had a melting temperature below $1250^{\circ}C$, and that pyroxene and diopside are the primary phases of the product. The crystallization temperature in the sample after modification was found to be higher than that in the sample before modification. The activation energy for crystallization was evaluated and found to be 467 kJ/mol for the sample before the process modification, and 337 kJ/mol for the sample after the process modification. The degree of crystallinity was evaluated and found to be 82 % before the process change and 87 % after the process change. Mechanical properties such as compressive strength and bending strength were evaluated and found to be excellent for the sample after process modification. In conclusion, the samples after the process modification were evaluated and found to have superior characteristics compared to those before the modification.