• Journal of the Mineralogical Society of Korea
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• v.21 no.2
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• pp.129-138
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• 2008

The characteristics of beneficiating kaolin mineral by liberation (selective grinding) and air classification have been investigated, comparing the grinding rates of ball mill and impact mill. The ore was ground using a ball mill and a impact mill to evaluate the grindability of the two grinding methods based on the constant production amount of fine particles in size less than 325 mesh. Then, the fine product was further separated into two fractions using an air-classifier and each fraction was chemically analyzed to compare the beneficiation efficiency of the two grinding methods. The chemical grade of kaolin mineral decreased as increasing the grinding rate of both the mills. particularly in the case of ball mill because of overgrinding impurities such as quartz and feldspar. In the case of the ball milling, the fine fraction less than 325 mesh was air-classified at a cutting point of $43\;{\mu}m$. The production rate of the air-classified concentrate was found to be 66.2 wt%, removing 5.3% of $Fe_2O_3$ and 34.6% of CaO. Under the same conditions mentioned above with the impact mill, the production rate of the air-classified concentrate was 64.4 wt%, removing 34.2% of $Fe_2O_3$, 67.6% of CaO and 25.0% of $TiO_2$. Therefore, our results indicate that impact mill is superior to ball mill in terms of impurity removal.

• Journal of Wetlands Research
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• v.22 no.2
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• pp.59-65
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• 2020

The purpose of this study is to determine the origin of organic matter on sediment at Sindu-ri tidal flat. Grain size, organic matter, C/N ratio and the 13C and δ15N ratio were measured at three stations (Stn. A, B, C) of the tidal flat. As a result, the spatial variation in sediment properties showed that organic matter was related positively to the sediment mud content. Organic matters originating from marine particulate organic matter (marine POM) and fish farm particulate organic matter (fish farm POM) showed sedimentation of organic matters at Stn. A, sandy tidal flat, though terrestial plant (TP) and benthic microalgae (BMA) did at Stn.C, muddy tidal flat. Meanwhile, Stn. B, the intermediate property of Stn. A and C, was affected by marine POM and BMA. Furthermore, it was revealed that the amount and origin of organic matters in the sediments depended on spatial variation, and the factors were different from the stations. Particularly, at the Stn. C, the sediment showed high concentration of TOC in terrestrial organic matter and smaller size particles (< 63 ㎛). These facts suggest the many small size particles and organic matter will affect the sediment environmental condition in the Stn. C.

• Resources Recycling
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• v.17 no.5
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• pp.28-36
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• 2008

The effect of attrition scrubbing on the recovery of platinum group metals (PGMs) from automobile catalytic converters has been investigated. Catalytic converters were first crushed into particles less than 2 mm and attrition scrubbed in the range of 60 min, and then they were sieved with several screens. The catalyst layer, $\gamma$-alumina, was dislodged from the surface of the supporting matrix into fine particles less than $45{\mu}m$ by attrition scrubbing. The fraction of fine particles less than $45{\mu}m$ increased as the residence time for attrition scrubbing increased. The composition of the fine fraction obtained at a residence time of 40 min was $CeO_2$ 19.3%, $ZrO_2$ 1.9% and PGMs 419 ppm. In the fine fraction, the recovery of y-alumina increased proportionally to the residence time. Simultaneously, the recovery rates of $CeO_2$, $ZrO_2$ and PGMs increased to 82.9%, 78.7% and 78.9%, respectively. The production of the fine fraction less than $45{\mu}m$ and the recovery of $\gamma$-alumina increased when the solid concentration and initial feed size increased. Therefore, the attrition scrubbing as the comminution and separation process was concerned to be effective for the recovery of catalyst layer from ceramic supporting matrix by physical impact and shearing action between particles in the scrubbing vessel.

• Journal of Aquaculture
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• v.10 no.1
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• pp.87-95
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• 1997

This experiment was conducted for compare domestic experimental microparticulated diets with imported commercial microparticulated diets in olive flounder larvae, Paralichthys olivaceus (Temminck et Schlegel). Fish larve were fed four microparticulated diets from 8th day after hatching. Four diets were two commercial microparticulated diets D and H, and experimental microparticulated diets K1 and K2 formulated each with different protein sources (diet K1 ; squid meal, blood meal, yeast extract, chlorella powder, olive flounder muscle, Lys, and Met ; diet K2 ; whole egg protein, krill meal, short-necked clam meal, squid muscle, live yeast, yeast extract, and casein). There were no significant differences on body weight, body length and survival rates among four diet treatments up to the 40th day after hatching. At the 83th day after hatching, fish fed diet D had a significantly higher survival rate than that of fish fed diet K2, whereas there was no significant difference between to diet H and K1. Fish fed diet D had a significantly higher body weight than these of fish fed diaet K1 and K2, whereas there was no significant difference between fish fed diet D and H. There was no significant difference on EPA and DHA of body fatty acid composition among four diet treatments up to the 83th day after hatching. These results show that nutritionally well-ballanced domestic microparticulated diets for olive flouner lavae can be developed.

• Proceedings of the Korean Magnestics Society Conference
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• 1991.05a
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• pp.25-26
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• 1991

• Proceedings of the Membrane Society of Korea Conference
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• 2001.05a
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• pp.33-43
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• 2001

• The Monthly Technology and Standards
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• s.24
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• pp.61-62
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• 2004

• 한국전자현미경학회:학술대회논문집
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• 1995.12a
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• pp.11-12
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• 1995

• 한국전자현미경학회:학술대회논문집
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• 1997.11a
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• pp.25-28
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• 1997

• 한국수산학회:학술대회논문집
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• 2005.05a
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• pp.37-38
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• 2005