• Cement Symposium
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• s.36
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• pp.110-115
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• 2009

2,3,4호 시멘트밀은 기존의 Tube MiIl 단독의 시멘트 분쇄 밀에 예비분쇄기(이하 "Polycom", Polysius 1992년 공급)를 설치, 합리화하여 운영되고 있는 Combi grinding type의 시멘트밀이다. 생산능력은 일 생산성 4,800T/D, Blaine $3,200cm^2/g$ 품질로 설계되었다. 금번 공정개선 부문인 예비분쇄공정의 Polycom 출구 Bucket Elevator(이하 "B/E") 및 Disagglomerator(이하 "DISA")로 위치는 Fig.1과 같다. Polycom 출구 B/E 및 DISA는 Polycom에서 분쇄된 원료를 분급기로 이송 및 cake 상태의 원료를 파쇄하는 설비이다. 상기 설비는 시멘트밀 공정에서 반드시 필요한 설비이나 - 잦은 고장에 따른 설비 가동율 저하 - 순환량 증가시 제한운전에 따른 생산효율저하를 일으키는 주된 설비로써 원단위 절감 및 설비가동효율 향상을 위하여 개선이 불가피한 설비임.

• Journal of Biosystems Engineering
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• v.9 no.2
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• pp.81-88
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• 1984

현재 축산농가에서 쉽게 구할 수 있는 곡류, 조사료 및 부산물을 활용하여 사료의 자급율을 높이는 것은 농가의 소득증대를 위하여 바람직한 일이다. 이러한 사료의 자급자족 체계를 위하여 소형이며 조작이 간편한 사료분쇄기가 요구된다. 따라서 농가에 많이 보급되어 있는 5~10 마력 (3.7-7.5 kw)의 동력경운기에 의하여 작동될 수 있는 소형 햄머타입의 사료분쇄기 시작기를 설계 제작하였다. 그리고 시작기의 성능을 분석하기 위하여 보리, 옥수수, 볏짚, 건초를 사료로 하여 시료의 공급율과 스크린의 구멍크기를 변화시켜가며 실험을 수행하였다. 이상과 같은 햄머 밀 시작기의 설계 및 성능시험을 통하여 얻어진 결과를 요약하면 다음과 같다. 1. 시작기의 평균분쇄능력은 보리의 경우 평균입자직경이 543 마이크론일 때 $82.7kg/kw{\cdot}h$였으며, 옥수수의 경우에는 평균입자직경이 408 마이크론일 때 $132.7kg/kw{\cdot}h$였다. 2. 최대 공급율로 분쇄할 때 소요동력은 보리의 경우 1.9kw, 옥수수의 경우 5.3kw, 볏짚의 경우 1.5kw, 건초의 경우 1.6kw을 필요로 하였으며, 5-10 마력(3.7-7.5kw)의 동력경운기로 개발된 햄머 밀을 작동함에는 별 문제가 없는 것으로 분석되었다. 3. 시작기로 시료를 분쇄할 때 곡류 분쇄는 물론 조사료 분쇄도 가능한 것으로 분석되었다. 4. 시작기에 의해 시료를 분쇄했을 때 분쇄물의 평균온도 상승폭은 $7.2-10.0^{\circ}C$였다. 이러한 온도는 분쇄물의 영양소 파괴및 저장상의 안정성을 고려할 때 안전한 범위의 온도상승으로 판단되었다. 5. 원료공급율과 스크린 구멍크기가 분쇄량과 분쇄정도에 5% 수준에서 유의성 있는 영향을 미쳤다.

• Journal of the Korean Geotechnical Society
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• v.19 no.4
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• pp.179-190
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• 2003

The grout based on solution type makes it difficult to get the improvement of ground strength and the effefct of water curtain because it has lower strength and durability than suspension type. Nowadays, the technology of particle acceleration, that enhance the material permeability, such as grout based on solution type, and inexpensive grout, is being required. For these reasons, in this study, using wet milling system, we evaluated physical properties of manufactured factors such as water-cement ratio of particles before being milled, optimum milling capacity by controlling milling time and rpm, viscosity of materials, permeation coefficient, and unconfined compressive strength. Also, using micro wet milling apparatus which could manufacture ordinary Portland cement and high speed shear mix which could forcefully separate conglomerate particles in situ, we performed electrical resistivity investigation and falling head permeability tests to analyze differences of grouting effects. From these results, we found that the permeability of the applied equipment was much superior, and in the case of using high speed shear mixer, particles of grout material were well separated.

• Applied Biological Chemistry
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• v.50 no.3
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• pp.160-166
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• 2007

This study was performed to analyze the molecular structural and physical properties changes of modified rice starch, which particle structure was broken using high impact planetary mill and ultra fine pulverizing techniques. The average diameter and specific surface area of rice starch after pulverization decreased 20% and increased 25%, respectively. Low molecular substances content in rice starch using GPC (gel permeation chromatography) increased from 36.5% to 59.5% after pulverizing of rice starch. Damaged starch contents in rice starch also increased from 16.4% to 99.2% after pulverizing of rice starch. Water holding capacity, solubility and transmittance of rice starch after pulverization increased compared to those of control. Apparent viscosity value of rice starch after pulverization decreased to 7% in control based on $30^{\circ}C$ and 20 RPM conditions.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.721-725
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• 2001

The main reason for applying pulverizer classifier-rotary type in fossil power plant is boiler high efficiency and energy saving movement in the government. This study intends to analyze the boiler efficiency through the pulverizer classifier-rotary type improvement in thermal power plant and makes its comparison to that of the used fixed type.

• Microbiology and Biotechnology Letters
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• v.14 no.5
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• pp.407-413
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• 1986

In an agitated bead reaction system, the enzymatic saccharification of uncooked starch was substantially enhanced. The enhancement mechanism was investigated front the view of the structural aspect of starch. The mechanical impact caused by the movement of the attrition-milling media resulted neither the destruction of microcrystalline structure nor the fragmentation of starch granule. instead, the most distinct phenomenon was the swelling of starch granule up to about 2.5 times, and the swelling mechanism was not similar with that caused by cooking. However, in the case of the enzyme addition in the attrition coupled reaction system, the swollen starch was easily fragmented into the large number of small particles by the synergistic action of the enzyme and milling-media. The exposed surface area of the fragmented particles plays the major role in enhancing the saccharification. The saccharification rate was quite different depending on the source of starch, the reason was discussed in terms of the granular structure of uncooked starches.

• Journal of The Korean Society of Grassland and Forage Science
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• v.41 no.1
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• pp.29-34
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• 2021

Near infrared reflectance spectroscopy (NIRS) is routinely used for the determination of nutrient components of forages. However, little is known about the impact of sample preparation and wavelength on the accuracy of the calibration to predict minerals. This study was conducted to assess the effect of sample preparation and wavelength of near infrared spectrum for the improvement of calibration and prediction accuracy of Calcium (Ca) and Phosphorus (P) in imported hay using NIRS. The samples were scanned in reflectance in a monochromator instrument (680-2,500 nm). Calibration models (n = 126) were developed using partial least squares regression (PLS) based on cross-validation. The optimum calibrations were selected based on the highest coefficients of determination in cross validation (R2) and the lowest standard error of cross-validation (SECV). The highest R2 and the lowest SECV were obtained using oven-dry grinded sample preparation and 1,100-2,500 nm wavelength. The calibration (R2) and SECV were 0.99 (SECV: 468.6) for Ca and 0.91 (SECV: 224.7) for P in mg/kg DM on a dry weight, respectively. Results of this experiment showed the possibility of NIRS method to predict mineral (Ca and P) concentration of imported hay in Korea for routine analysis method to evaluate the feed value.

• Korean Chemical Engineering Research
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• v.58 no.1
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• pp.84-91
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• 2020

The efficiency of the synthetic magnesium silicate used in basic polyols and edible oil purification is evaluated by its purification ability and filtration rate and is affected by the particle size and surface area of magnesium silicate. In this study, it was investigated the change on the particle size of magnesium silicate was influenced by the reaction temperature, injection rate, injection order (Si, Mg) and Mg/Si reaction mole ratio. The synthesized magnesium silicate was compared and analyzed for the synthesis, grinding, and refining processes. In the synthesis process, the reaction temperature and feed rate did not affect the average particle size change of magnesium silicate, while the reaction molar ratio of Mg / Si and the order of injection acted as main factors for the change of average particle size. The average particle size of magnesium silicate increased by 8.7 ㎛ from 54.4 ㎛ to 63.1 ㎛ at Mg injection when Mg molar ratio increased from 0.125 to 0.500, and increased by about 4.8 ㎛ from 47.3 ㎛ to 52.1 ㎛ at Si injection. The average particle size according to the order of injection was 59.1 ㎛ for Mg injection and 48.4 ㎛ for Si injection and the difference was shown 10.7 ㎛, therefore the filtration rate was about 2 times faster under the condition of Mg injection. That is, as the particle size increases, the filtration time is shortened and washing filtration rate can be increased to improve the productivity of magnesium silicate. The cake form of separated magnesium silicate after filtration becomes a solid through drying process and is used as powdery adsorbent through the grinding process. As the physical strength of the dried magnesium silicate increased, the average particle size of the powder increased and it was confirmed that this strength was affected by the reaction molar ratio. As the reaction molar ratio of Mg / Si increased, the physical strength of magnesium silicate decreased and the average particle size after grinding decreased by about 40% compared to the average particle size after synthesis. This reduction of strength resulted in an improvement of the refining ability due to the decrease of the average particle size and the increase of the amount of fine particle after the pulverization, but it resulted in the decrease of the purification filtration rate. While the molar ratio of Mg/Si was increased from 0.125 to 0.5 at Mg injection, the refining ability increased about 1.3 times, but the purification filtration rate decreased about 1.5 times. Therefore, in order to improve the productivity of magnesium silicate, the reaction molar ratio of Mg / Si should be increased, but in order to increase the purification filtration rate of the polyol, the reaction molar ratio should be decreased. In the synthesis parameters of magnesium silicate, the order of injection and the reaction molar ratio of Mg / Si are important factors affecting the changes in average particle size after synthesis and the changes of particle size after grinding due to the changes of compressive strength, therefore the synthetic parameter is an important thing that determines productivity and refining capacity.

• Food Engineering Progress
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• v.13 no.4
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• pp.335-340
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• 2009

This study was performed to analyze changes in the molecular structural and physical properties of modified corn starch, in which particle structure was broken using high impact planetary mill and ultra fine pulverizing techniques. The average diameter and specific surface area of the modditied corn starch after pulverization decreased 50% and increased 567%, respectively. Content of low molecular substances mersured using gel permeation chromatography (GPC) increased from 21.0% to 86.5% after pulverizing corn starch. Damaged starch content also increased from 9.63% to 83.57% after pulverizing corn starch. After pulverization, gel formation capacity corn starch was reduced compared to that of control by structure breakdown.

• Journal of the Korea Institute of Building Construction
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• v.20 no.1
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• pp.1-9
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• 2020

Chloride ion, which penetrates into the cement composites from the outside, generally diffuses by the concentration gradient. Chloride ions are adsorbed by the chemical reaction with cement hydrates. Recent studies have shown that anion exchange resin (AER) powder can effectively adsorb the chloride ion in the cement composites, and thus, the cement composites containing AER have a high chloride adsorption capacity and a good resistance for chloride penetration. In this study, the chloride adsorption ability of the AER powder was investigated under the conditions of distilled water and calcium hydroxide saturated solution to determine if the AER powder is less effective to increase the chloride adsorption ability after grinding process. The chloride adsorption ability of AER powder was compared with the previous research about the chloride adsorption of AER bead. In addition, the compressive strength, chloride diffusion coefficient (using NT Build 492 method), and the chloride profile of cement mortar substituted with AER powder were investigated. There was no decrease in the chloride adsorption capacity of AER powder but increase in the kinetic property for chloride adsorption after the grinding process. The AER powder could absorb the chloride ion in the mortar quickly, and showed better chloride ion adsorption ability than the cement hydrates.