• Economic and Environmental Geology
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• v.28 no.2
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• pp.147-154
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• 1995

Coal fly ashes collected from the Samcheonpo and the Seocheon Power Plants were analyzed for major and minor components and heavy metals such as As, Cd, Co, Cr, Cu, Ga, Hg, Mo, Ni, Pb, Sb, V and Zn in order to suggest basic data to apply coal fly ash as fertilizer or soil ameliorator. The specific gravity of the samples was less than 2.0, and amounts of organic matter range from 5.0% to 12.3%. The identified minerals by XRD were mainly quartz, mullite and pyrite in anthracite coal, and mainly quartz and mullite in bituminous coal. Generally, the contents of heavy metal elements analyzed were lower less than those of soil, though higher in some samples. Element couples of some elements( e.g., As-Mo, Zn ; Mo-As, Sb, V, Zn ; Sb-Zn ) show positive correlations with each other, but the high correlations of toxic elements such as As, Pb, Cd and Hg indicate to give attention to apply coal fly ash as fertilizer or soil ameliorator.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.1
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• pp.182-188
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• 2008

The compounds of recycled polyethylene(PE) and fly-ashes were prepared. Polymers used were sorted PE from mixed plastics of household waste and Low Density Polyethylene(LDPE) and Linear Low Density Polyethylene(LLDPE) recycled from the scrap of packaging film plants. Fly-ashes were from the power plant and from the household waste incinerator. The tensile strength of recycled LDPE and LLDPE compounds decreased and the flexural modulus increased with greater amount of the power plant fly-ash. Anthracite fly-ash gave rise to slightly higher tensile and flexural strength of the LLDPE mixtures than bituminous coal fly-ash presumably due to higher content of unburned carbon. The incinerator fly-ash introduced to household waste PE enhanced both tensile strength and flexural modulus of the compounds. When LDPE and household waste PE were used together, the synergistic effect of incinerator fly-ash to household waste PE was offset by reduced crystallization of LDPE due to the filler particle. The compounds of household waste PE and incinerator fly-ash might be applied to structural materials for such as sewage pipe, which reduces the waste treatment cost and conserve the environment and resources.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.3
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• pp.226-235
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• 1996

This pot experiment was conducted to investigate the changes of leaching in percolated water of paddy soil in which rice was cultivated in conditions of 0%, 5%. 30% addition of bituminous and anthracite fly ash respectively in greenhouse. pH in percolated water was higher in non cultivated plot than in cultivated plot. pH of the fly ash treated plot was higher than that of the control plot. pH in the cultivated plot decreased gradually during the cultivation. The contents of $NH_4-N$, $NO_3-N$ and K in percolated water decreased rapidly after mid-July, and was very low in the cultivated plot. Over the cultivation time, P contents in percolated water was very low. $SiO_2$, contents in percolated water decreased rapidly after June. Na contents in percolated water was highest in mid-June and then decreased gradually. In the cultivated plot, Ca contents in percolated water was higher than that in the control plot. During the cultivation, Ca contents in percolated water decreased gradually. But, in later-term of cultivation. Ca contents in percolated water was relatively Mgh. Mg contents in percolated water decreased after mid-July, but decreased continuously till the later-term of cultivation. EC in the percolated water was highest in mid-June. and then decreased gradually. EC of fly ash treated plot was higher than that of the control plot. The soil pH was increased and phosphate content in the soil was accumulated very high by application of fly ashes in paddy field after rice cultivation. Fly ash treatment did not increase the contents of elements in percolated water compared with the control plot. The difference between anthracite and bituminous fly ash was not so clear. Fly ash treatment, inhibited early growth and tillering. But, in later-term of cultivation, the inhibition effects of nonproductive tillering was expected. Fly ash treatment will be good if it was applicated after last year's harvest because leaching would happen over fallowing time. Contents of inorganic elements in percolated water of fly ash treated plot was not so high compared with that in the control plot.

• Korean Journal of Soil Science and Fertilizer
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• v.27 no.2
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• pp.65-71
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• 1994

This study was conducted to investigate the influence of treatment of fly ash on heavy metal contents in the arable soils. Rice was cultivated on the two types of paddy field(clay loam and sandy loam soil) with 0, 4, 8, 12t/10a of anthracite fly ash and bituminous coal fly ash, respectively. And soybean was cultivated on the same types of upland field with those of 0, 3, 6, 9t/10a, respectively. At the harvest time, the heavy metal contents in surface and subsoil were investigated. The results were summarized as follows : 1. Anthracite fly ash. 1) In the paddy field of clay loam, the contents of Cu and Zn in the surface soil and Cd and Ni in the subsoil were increased with the increase of the amount of fly ash applied, but the others didn't show that tendency. 2) In the paddy field of sandy loam, only the content of Fe was increased in the surface and subsoils. 3) In the case of upland soil, the concentration of Ni and Cr in the surface soil and Cd in the subsoil were increased in the clay loam soil, and those of Cr in the surface soil and Pb in the subsoil were increased in the sandy loam soil. 2. Bituminous coal fly ash 1) In the paddy field of clay loam, the contents of Cu and Zn in the subsoil were increased with increase of the amount of fly ash applied, but in the case of sandy loam, those of Pb and Ni in the surface soil were increased. 2) In the upland soil of clay loam, the concentration of Ni in the surface soil and Pb in the subsoil were increased. 3) In case of upland soil of sandy loam, the contents of Cr and Fe were increased in the surface and subsoil, respectively, but those of Cu and Mn were increased in the both of the surface and subsoil.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.3
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• pp.236-242
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• 1996

This study was conducted to investigate the changes of heavy metals in percolated water of paddy soil in which rice was cultivated in conditions of 0%, 5%. 30% addition of bituminous and anthracite fly ash respectively. In cultivated plot, the contents of Fe in percolated water increased gradually during the cultivation. But there was no sharp difference of Fe contents in fly ash treated plots. The contents of Mn in percolated water increased gradually during the cultivation and was high in the cultivated plot. But difference in the contents of Mn among plots not clear. The contents of Zn in percolated water was highest during 20-25 days in the cultivation, thereafter decreased gradually. The fly ash did not cause to increase the contents of Zn in percolated water. The contents of Cu in percolated water decreased through the cultivation. Fly ash treatment did not cause to increase the contents of Cu in percolated water. The contents of Pb in percolated water decreased gradually over the cultivation. Fly ash treatment did not largely influence to Pb percolation. In mid-July. Pb did not almost appeared in percolated water. The contents of Cd was highest about 15 days of the transplant, thereafter decreased gradually. After 40 day of the cultivation, leach of Cd stopped. When fly ashes were applied in paddy soil, the contents of heavy metals in percolated water was not so much compared with control plot. It seems that originally low contents of heavy metals in fly ash and decrease in solubility of heavy metals in a relatively high soil pH make it possible to use fly ash as a soil conditioner.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.2
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• pp.151-157
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• 1998

Fly ash application with a rate of 0, 50, 100, $150Mg\;ha^{-1}$ in clay loam paddy, which had properties of pH 5.3 and low contents of silicate and boron, gave a strongly positive effects on the growth and yields of malting barley showing better responses in bituminous coal fly ash(BCFA) than anthracite fly ash(AFA). Especially, soil chemical characteristics improved greatly by fly ash were pH, available phosphate, exchangeable calcium, available silicate, and boron. Shoot length and the number of tiller till defrosting season appeared the most positive responses by application of BCFA $50Mg\;ha^{-1}$ and AFA $100Mg\;ha^{-1}$. However, the number of spikelet per panicle at heading stage was proportionally increased to the rates of each fly ash. As a result, the grain yields of malting barley were increased to $13.8(4.221Mg\;ha^{-1}){\sim}37.7%(5.106Mg\;ha^{-1})$ by application of BCFA and to $1.1(3.75Mg\;ha^{-1})-20.6%(4.473Mg\;ha^{-1})$ by application of AFA. Protein contents in the grain was the highest in $150Mg\;ha^{-1}$ plot, showing 10.5 and 10.8% by BCFA and AFA application, which were suitable for malting. At harvesting, plants showed 49 and 58% of lodging indices by application of BCFA 100 and $150Mg\;ha^{-1}$, respectively, which were equivalent to two fold values of those by AFA.

• Journal of Industrial Technology
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• v.15
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• pp.175-185
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• 1995

Under the new environmental regulations announced by the government, utilities will have to cut their sulfur dioxide emissions by 60% from 1991 levels by the year of 1999. Sulfur dioxide emissions can be reduced prior to combustion by physical, chemical or biological coal cleaning. The new technology of high gradient magnetic separation (HGMS) offers the potential of economic separatoins of a variety of fine, weakly magnetic minerals including inorganic sulfur and many ash-forming minerals from coals. In the present paper, magnetic separation tests have been conducted on Korean anthracite and high-sulfur Chinese coal to investigate the feasibility of these techniques for reducing sulfur content from coals. In wet magnetic separation, the studied operating parameters include particle size, pH, matrix types, feed solids content, feed rate, number of cleaning stages and etc. The results shows that for wet separation, 60~70% of total sulfur was removed from coals with over 80% combustible recovery, on the other hand, for dry separation, 47.6% of total sulfur was removed from coals with 75% recovery.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.230-233
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• 2008

The vanadium rich ash of petroleum coke can give a slagging problem during because of the high melting point of $V_2O_3$. For continuous removal of the slag, petroleum coke is often mixed with coal, and the viscosity of the mixed slag is an important property, determining the gasification temperature. The viscosities of the mixed slag from various mixing ratios of petroleum coke and a bituminous coal were investigated. When mixed with a crystalline coal slag, $T_{cv}$ was increased at a higher the coke content in the mixed feed. When the $V_2O_3$ concentration was greater than 4.5%, it was difficult to get accurate measurements of $T_{cv}$. The SEM/EDX analyses of the cooled slag revealed that the major crystalline phase was anorthite, and $T_{cv}$ should be related to the formation temperature of anorthite. The SEM/EDX analyses also showed that, at low concentrations of vanadium, part vanadium formed a crystalline phase with Al-Si-Ca-Fe, and the rest remained in the glassy phase, suggesting that vanadium existed as a slag component at the low viscosity region. At a high concentration, vanadium forms a phase with Ca, and the Ca-V phase was separated from the slag phase, and formed a layer above the slag. FeO in petroleum coke also played an important role determining viscosity: at high temperatures, increased FeO lowered the viscosity, but as it formed a spinel phase, the depletion of FeO in the slag resulted in a higher viscosity.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.8 no.2
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• pp.59-66
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• 1988

At the present time, annually about 2 million tons of coal ashes are generated from thermal power plants in Korea, however, they are dumped into ash ponds mixed with sea water very expensively. In this thesis, engineering characteristics of bituminous and anthracite ashes are studied to utilize them as construction materials. The coal ash is non-plactic material and its grain size falls in the range of silt, but it has better soil engineering characteristics than general soils of same grain size. For example, the permeability, shearing strength, CBR, and consolidation properties match to that of sandy soils, moreover, strengthening by hydration can be expected with the lapse of year because of CaO presence in the components. So, utilizing those coal ashes in a productive way as reclamation or banking materials is expected.

• Resources Recycling
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• v.23 no.1
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• pp.40-47
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• 2014

Feasibility of utilizing unburned carbon residue in coal ash as a potential precursor for the production of activated carbon was assessed to seek for solution to recycle unburned carbon residue. The unburned carbon concentrate generated from the 4 stages of cleaner flotation has a grade of 87% carbon. The crystalline impurities in the concentrate included quartz and mullite. Unburned carbon had a low specific surface area of $10m^2/g$, which might be related to a high degree of coalification of domestic anthracite coal. Carbon particles were mostly porous and have a turbostratic structure. When 1g of carbon was activated with 6g of KOH powder, the highest specific surface area value of $670m^2/g$ was achieved. Low wettability of unburned carbon particles, which was resulted from high temperature combustion in a boiler, might cause poor pore formation when they were activated by KOH solution. The activated carbon produced in this study developed micropores, with an equivalent quality of general-purpose activated carbon made from coal. Hence, it is concluded that chemically treated unburned carbon can be used for water purification or an alternative to carbon black as it is.