• The Journal of Engineering Geology
• /
• v.18 no.1
• /
• pp.103-115
• /
• 2008

The purposes of this study are to understand characteristic water-rock interaction mechanisms of groundwater in the granite area of Geochang and Hapcheon areas, Gyeongnam-do and to clarify the origin of fluoride. The possible water-rock interaction process and the source of fluorine were studied using water chemistry, rock chemistry, mineralogy by XRD, and microtexture analysis by backscattered electron image of the electron microprobe. No clear relationships between F and hardness was found. But the fluorine content increases to some extent with pH and well depth. Preferential alteration due to water-rock interaction took place along edges or cleavage, or margins of biotite. Because biotite is highly subject to alteration in granite aquifer, fluorine in groundwater is originated from the leaching of biotite.

• Korean Journal of Food Science and Technology
• /
• v.14 no.2
• /
• pp.141-145
• /
• 1982

Busuge is conventional snack food in Korea which is made from steeped glutinous rice. The effect of the steeping time on total acidity, viscosity, canons, phosphorus and raising power of glutinous rice was investigated. Total acidity was increased from 0.3 to 1.02% by steeping for 20 days at $10^{\circ}C$. Viscosity was increased from 25.5 to 32.4 cP after 14 days steeping and thereafter decreased to 23.5 cP. K, Na, Ca, Mg and P were leached 68, 67, 85 and 16% on 20 days steeping, respectively. K, Na and P were leached in the initial period, and Ca, Mg in the middle period of steeping. Raising power was increased according to the acidity increase and leaching of Ca, Mg and inorganic phosphorus during steeping. However, influence of the former on raising power was greater than the after.

• Environmental Engineering Research
• /
• v.19 no.1
• /
• pp.37-40
• /
• 2014

This research investigates the quality changes during composting of bagasse and pig manure amended with 30% of surfactant-coated charcoal (SC). Two treatments, 30% uncoated charcoal (UC) amendment and no charcoal (NC) amendment, were done as control. Charcoal was coated with 0.37 mM tetradecyltrimethylammonium bromide (TDMA), a cationic surfactant, at the dosage of 10 g/L. At the end of the composting period, the carbon to nitrogen (C/N) ratio of SC amendment was 9.7; whereas, the C/N ratios of UC and NC amendment were 12.6 and 21.4, respectively. Plant nutrients contents of the compost produced from SC amendment were 20.7 mg $NH_4{^+}-N/g$, 42.8 mg $NO_3{^-}-N/g$, and 41.7 mg P/g. High nitrate and phosphate concentrations in SC amendment were due to the adsorption of these anions on the positive charge of TDMA. Desorption of plant nutrients retained in the compost pellets was also investigated. It was predicted that nitrate was fully desorbed from a pellet at 23 days for SC amendment, which was later than UC (14 days) and NC (10 days) amendment. A slow release of nitrate from the compost pellet will reduce the nitrate leaching into the environment. Thus, the adding of SC in the compost pile is one of the alternative methods to improve the quality of compost and plant nutrient retention.

• Resources Recycling
• /
• v.27 no.1
• /
• pp.38-44
• /
• 2018

A large amount of Nd-Fe-B magnet scraps are generated during magnet manufacture process. In this study, selective chlorination of the rare earth elements by hydrogen chloride gas which obtained from the pyrolysis of polyvinyl chloride (PVC) was investigated. In thermogravimetric analysis, drastic weight loss was occurred at about 500 K and 710 K. At the isothermal experiments, the weight loss reaches about 30% above 673 K. XRD patterns characterized that after each experiments, ${\alpha}$-Fe, Nd oxychloride, Nd chloride, and Fe chlorides were formed, and the leaching residues remain only ${\alpha}$-Fe. The yields of Nd, Dy, and Fe for the isothermal experiment were increased with temperature and peaked at 873 K. As PVC ratio increased, the yields of Nd, Dy and Fe were also increased.

• Korean Journal of Soil Science and Fertilizer
• /
• v.44 no.1
• /
• pp.15-21
• /
• 2011

Transport of heavy metals such as Cd is affected by several rate-limiting processes including adsorption and desorption by exchange reactions in soils. In this study, column transport and batch kinetic experiments were performed to assess Cd mobility in a double-layered soil with a reclaimed saline and sodic soil (SSS) as top soil and macroporous granule (MPG) as a bottom layer. For individual soil layer having different physical and chemical properties, Cd was considered to be nonlinear reactivity with the soil matrix in layered soils. The dispersive equation for reactive solutes was solved with three types of boundary conditions for the interface between soil layers. The adsorption of Cd with respect to the saline-sodic sandy loam and the MPG indicated that the nature of the sites or the mechanisms involved in the sorption process of Cd was different and the amounts of Cd for both of samples increases with increasing amounts of equilibrium concentration whereas the amount of Cd adsorbed in saline-sodic sandy loam soil was higher than that in MPG. The results of breakthrough curve indicating relative Cd retardation accompanied by layer material and sequence during leaching showed that the number of pore volumes to reach the maximum relative concentration of 1 increased in the order of MPG, SSS, and double layer of SSS-MPG. Breakthrough curves (BTCs) from column experiments were well predicted with our double-layered model where independently derived solute physical and retention parameters were implemented.

• Applied Chemistry for Engineering
• /
• v.8 no.4
• /
• pp.679-684
• /
• 1997

The major constituents in spent FCC catalysts are Si, Al, Fe, Ti, alkali metals and some others. The spent catalyst is also composed small amounts of rare metals such as Ce, Nd, Ni and V. The selective adsorption and concentration of Ce and Nd from the leaching solution of spent FCC catalysts with sulfuric acid($0.25mol/dm^3$) were carried out by the column method with a chelate resin having a functional group of aminophosphoric acid type. Ce and Nd were separated from eluate liquor containing Al, Nd and V by the precipitation process with oxalic acid. Vanadium is purified from chloride ion coexistance by solvent extraction, employing tri-n-octyl phosphine oxide as extractant with Al in the raffinate solution. Rare metals with the purity of 99 percent were obtained from the spent FCC catalyst.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.11a
• /
• pp.549-552
• /
• 2008

The cement is accomplished with CaO, SiO2, Al2O3 and Fe2O3, etc. After pulverizing materials of the limestone, the sand and the clay(shale), iron ore, the cement becomes clinker materials sintering from the rotary kiln of oxidizing atmosphere. The part in the materials of the clinker is substituted with slag, sludge etc. and it is used. because The chromium which is to be included in the clinker materials, in sintering process hexavalent chromium is converted with the chrome. Consequently it changed the type and a content of clinker materials and test hexavalent chromium of the clinkers which is manufactured.

• Proceedings of the IEEK Conference
• /
• 2001.10a
• /
• pp.453-458
• /
• 2001

This study was performed to reuse the dyeing wastewater sludge treated by Fenton process through the solidification/stabilization technique. To solidify the dyeing sludge the industrial by-products such as blast furnace slag, fly ash and waste sand with cement were used. The laboratory scale and pilot scale test were conducted at room temperature to make construction brick which has high compressive strength and low leaching of heavy metals. The experimental results showed that blast furnace slag and fly ash could be used instead of cement and the products satisfied the regulation of Korean Standards. The blast furnace slag increased the compressive strength and the optimum ratio of slag/dyeing sludge on dry basis was found 0.4. The solidifying agent of SB series could increase rapidly the compressive strength and the optimum ratio of solidifying agent/sludge on dry basis was 0.26 at which the strength was two times compared with non-added condition. The portion of waste and industrial by-products in matrix was over 80%. From the pilot test the optimum pressure in molding was 100kg/$\textrm{cm}^2$ at which the compressive strength was over 100kg/$\textrm{cm}^2$. And the strength increased continuously to 160kg/$\textrm{cm}^2$ until 120 days curing time due to pozzolanic reaction. When SB-20 as a solidifying agent was used, the unconfined compressive strength of dyeing sludge could be obtained 110kg/$\textrm{cm}^2$ which satisfied the regulation of cement brick in Korea Standard(KS).

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.8 no.2
• /
• pp.89-98
• /
• 1988

This research evaluated factors on cement-based solidification process designed for hazardous sludge produced from electroplating industry. Four factors of sand/cement ratio, water/cement ratio, amount of wet sludge and amount of a precipitator, were investigated in terms of leachability and compressive strength of the solidified materials. Results of triplicate tests and statistical analysis indicated that sand/cement ratio(S/C) had the greatest effect on leaching of Cr(VI) from the solidified materials while water/cement ratio(W/C) on Zn and compressive strength. Cr(VI) was fixed better than Zn by portland cement. An experimental modeing was developed to estimate leached metal concentration and compressive strength at a given condition. Proper mixing criteria were also suggested for the use of the solidified mixture as construction materials. In solidification of 30g dry sludge, optimal condition was studied for S/C ratio, W/C ratio and the weight of precipitator which were 1, 1.5 and 1.075g respectively.

• Korean Journal of Soil Science and Fertilizer
• /
• v.18 no.3
• /
• pp.260-264
• /
• 1985

Ferrallitique soils are real tropical soils, with an oxic B horizon such a horizon is at least 30cm thick, has > 15% clay, diffuse horizon boundaries, no weatherable minerals and a CEC of clay < 16 me per 100g. These soils are in general the real reddish or yellowish very uniform tropical clay soils with an orchric A horizon and a deep B horizon, otherwise almost characterless. The soil profile looks uniform and maybe some metres thick. It is well drained, has a good permeability and a stable structure. As there is little or no weatherable mineral, because these soils are old and exhausted of bares, natural fertility is very low. There has been a complicated process of soil formation. Intensive and continuous weathering over a very long period has resulted in leaching of bases and silica, in relative accumulation of resquioxides and in formation of kaolinitic clay. Until recently, there has been much confusion in classifing and naming tropical soils. Particularily what are now Ferralsols in the FAO scheme, and Oxisols in Soil Taxonomy. Old names of various classification system are: Lateritic soils, Latosols, Ferrallitic soils. For agriculture, these soils are important, but chemically very poor, not only because of a low CEC but also because of deficiency of bases, especially Ca, Mg, and K, strong P fixation and high exchangeable Al percentage.