• Journal of the Mineralogical Society of Korea
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• v.22 no.3
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• pp.191-197
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• 2009

It is very important to raise the purity of silica for manufacturing metallurgical-grade silicon because the purification of silicon in the smelting process is very difficult. In present study, the silica sand which is obtained from Vietnam was mineralogically analyzed. Based on the results, a novel process to separate impurities from the silica sand was developed, which consisted of classification, specific gravity and magnetic separation steps. Using the developed process, high-grade silica sand concentrate containing over 99.8 wt% $SiO_2$ was prepared, being suitable for manufacturing the metallurgical-grade silicon.

• Journal of The Korean Society of Grassland and Forage Science
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• v.34 no.3
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• pp.202-208
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• 2014

This study was carried out investigate the effects of dietary addition of mineral and sugar on the dry matter intake, daily gain, yield grade and quality grade of Hanwoo (Bos taurus coreanae) steers. Three diets fed to steers included a control diet (concentrate mix and rice straw : C) and two treatments diet (control diet + black sugar 100 g + mineral 100 g : T1, and control diet + black sugar 150 g + mineral 50 g : T2). The results are summarized as follows; total feeding intake, body weight gain and daily gain did not show significant differences among the three treatments. Cold carcass weight was significantly (p<0.05) higher in T2 than in the other two treatments (C and T1). There was no significant difference in yield traits of back fat thickness, longissimus muscle area and yield grade among the three treatments (C, T1 and T2). Marbling score showed significantly (p<0.05) higher in order of T2 (5.67) > T1 (4.67) > C (3.67). Meat color, fat color, texture and maturity were no significant difference. Quality grade was higher in T2 than in the other two treatments (C and T1), but there was no significant difference. The results show that marbling score and quality grade of Hanwoo can be increased by high dry matter intake with feeding addition of mineral and sugar.

• Resources Recycling
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• v.20 no.4
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• pp.3-22
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• 2011

Until recently, domestic high grade limestone have mainly mined so high grade limestone deposits have reduced. Because of exhaustion of high grade limestone, mine of limestone have moved from ground to deep position, the grade of limestone become lower because the amount of impurities and colored mineral increased as mining position become deeper. This paper was described about grade improvement of limestone to make a high grade limestone and suitable quality of limestone products by analysis of ore genesis and characteristics, supply and demand situation, use patterns and application standards of domestic lime-stone.

• Journal of the Korean Ceramic Society
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• v.51 no.2
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• pp.132-137
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• 2014

The study was performed with low-grade limestone, which is used to make cement or is disposed of due to its low CaO content. In this study, the optimal condition of limestone with which to manufacture precipitated calcium carbonate (PCC) and limestone in fiber was determined through in-situ reactions. The best firing condition is with slaked lime with rapid cooling after 2 h of firing at $1000^{\circ}C$. In addition, the content of CaO can be increased by sorting the low-grade limestone using a 200 mesh filter, and the optical quality of old newspaper (ONP) was similar when using both low-grade and high-grade limestone. Also, controlling the particle size of PCC is an important factor pertaining to the optical characteristics of paper.

• Journal of the Korean Ceramic Society
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• v.32 no.1
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• pp.71-82
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• 1995

The weathered two-mica granite is widely distributed in Korea and called a kind of ground rock for kaolin. The major minerla compositions are consist of this quartz, feldspar, mica and clay mineral. At present, only a small portion of this granite is used as the material for the low-grade tile industry due to the low S.K. value and the high contents of impurities such as Fe2O3 and FeO. The low S.K. value is caused by feldspars not weathered to clay minerals. The refinement of this thus has been required for the recent shortage of the resources of high-grade one. This paper concerns an optimum hydrothermal treatment condition to refine the low-grade weathered two-mica granite of which impurities are feldspar mineral and Fe2O3. FeO components in using for the main material of ceramic industry. And then, from this result, we tried to fine out the basic formation mechanism of clay mineral from feldspar etc and develope the effectual utilization method of this.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.216-217
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• 2018

The three kinds of tests are used to further study the effect of the amount of mineral powder in this mixture design. Firstly, comparing the relationship of the content of mineral powder and asphalt bitumen membrane thickness at different asphalt content, through film thickness to determine the range of gradation and asphalt content in laboratory tests, Grade A and Grade D, asphalt content 2.6%, 3.4% and 3.8% are set for the benchmark, then fatigue properties of the test are carried out in the established range, the result show that asphalt film thickness decreases with the addition of mineral powder. The result also show that fatigue properties of asphalt rubber mixture will reduced, when mineral powder added in, especially when the asphalt content is high.

• Mineral and Industry
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• v.25
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• pp.1-10
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• 2012

In this present work, the froth flotation of lithium ore from Boam mine located in Wooljin, Kyungbuk has been carried out to produce high-grade lithium concentrate. The sample ore-Lepidolite mainly contained silicate mineral (quartz, muscovite) and calcite. In consequences of the experiment, it has been possible to obtain relatively high-grade lithium while using anionic acid (oleic acid) to remove calcite before the froth flotation for lithium concentrate. Among the amines collectors (Armac-T, Armac-C, Armafloat-18, Armafloat-1597), Armac-T has been relatively effective than another ones. Under the optimum condition (collector : Armac-T 100g/t, frother : AF65 50g/t, depressants : $Na_2SiO_3$ 600g/t and Lactic acid 100g/t, pulp density : 20%, pH 5.5, number of cleaning : 2), it has been obtained relatively high-grade lithium concentrate ($Li_2O$) with recovery of 80.3% and with grade of 4.33%.

• Resources Recycling
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• v.18 no.5
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• pp.19-25
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• 2009

Molybdenite concentrate ($MoS_2$) is the major mineral for the molybdenum industry, of which the industrial processing is first converted to technical grade molybdenum trioxide ($MoO_3$) by its oxidative roasting and purification, used as a raw material for manufacturing several molybdenum compounds. In the present work, detailed experimental results for the oxidative roasting of low grade Mongolian molybdenite concentrate are presented. The experiments were carried out in the temperature range of 793 to 823 K under an oxygen partial pressure range of 0.08 atm to 0.21 atm by using a thermogravimetric analysis technique. The molybdenite concentrate was an average particle size of $67\;{\mu}m$. In the oxidative roasting of low grade Mongolian molybdenite concentrate, more than 95% of molybdenite was converted to molybdenum trioxide in 60 min. at 828 K. The lander equation was found to be useful in describing the rates of the oxidative roasting and the reaction order with respect to oxygen concentration in a gaseous mixture with nitrogen was 0.11 order.

• Resources Recycling
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• v.30 no.5
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• pp.57-66
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• 2021

In this study, we attempted to separate and recover Cu from low-grade copper ore by a hydrometallurgical process. The leaching sample obtained after crushing and sieving by 0.355 mm of low-grade copper ore contained 1.5% Cu, 4.7% Fe, 1.0% Mn, and 0.3% Zn. The Cu in the oxide ore was very well leached into sulfuric acid and 97% Cu leaching efficiency was achieved at 80℃ and 3 M sulfuric acid (H₂SO₄). From the leaching solution, Cu was separated by solvent extraction from Fe, Mn, and Zn using LIX984N. The separation tendency between Cu and other metals was confirmed through the distribution ratio and separation factor. By plotting the McCabe-Thiele Diagram, the optimum condition for recovering Cu is 5 vol.% LIX984N, 2-stage counter-current solvent extraction, and an O/A ratio of 0.5. Using this method, 99% of the Cu was extracted and a CuSO₄ solution was finally obtained that contained 1.6 g/L Cu after the stripping process using 2 M H₂SO₄.

• Resources Recycling
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• v.32 no.2
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• pp.3-11
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• 2023

The aim of this study was to develop a physical treatment method for obtaining iron concentrate with a grade higher than 60% from slag generated in the Waelz Kiln (WK) process. The size of the WK slag used in this work was several millimeters, with T-Fe and ZnO contents of 40.24% and 1.03%, respectively. The slag samples were pulverized in a laboratory rod mill for various grinding times, followed by a magnetic separation test under a low magnetic intensity of 0.05 T initially. The results showed that the highest iron grade was obtained from samples with a grinding time of 10 min. Additionally, for a grinding time of 20 min, the highest grade and recovery ratios were achieved at a magnetic intensity of 0.8 T. Based on these findings, the optimal physical treatment process proposed in this study resulted in iron concentrates with a grade of 61.34% and an enrichment ratio of 1.52.