Eco-Materials Processing and Design IX

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Authors: Chang Hwan Seo, M. J. Jeong, In Young Jung, Bo Young Hur
Abstract: Aluminum alloy foams, new materials belonging to a special class of porous materials, have been prepared using melt foaming method. Silicon was chosen alloying element due to its low density, high strength, effective casting and reduced shrinkage. Melt foaming method is cost-effective method to fabricate metal foam. Usually, TiH2 is applied to blowing agent, but its cost is high. CaCO3 is one of candidates to substitute TiH2 in the economic view-point. For the comparison of formability, Mg alloy foams were prepared by TiH2 and CaCO3. However, the decomposition temperature of CaCO3 is higher than that of TiH2. This paper will be discussed on the possible usage of CaCO3 in the Al melt.
Authors: Yasuo Yamada, Takumi Banno, Yun Cang Li, Cui E Wen
Abstract: In the present study, porous nickel foam samples with pore sizes of 20 μm and 150 μm and porosities of 60 % and 70 % were fabricated by the space-holding sintering method via powder metallurgy. Electron scanning microscopy (SEM) and Image-Pro Plus were used to characterise the morphological features of the porous nickel foam samples. The anisotropic mechanical properties of porous nickel foams were investigated by compressive testing loading in different directions, i.e. the major pore axis and minor pore axis. Results indicated that the nominal stress of the nickel foam samples increases with the decreasing of the porosity. Moreover, the foam sample exhibited significantly higher nominal stress for loading in the direction of the major pore axis than loading in direction of the minor pore axis. It is also noticeable that the nominal stress of the nickel foams increases with the decreasing of the pore size. It seems that the deformation behaviour of the foams with a pore size in the micron-order differs from those with a macro-porous structure.
Authors: Jin Woo Lee, Jong Oh Kim, Jong Tae Jung
Abstract: The amount of food waste has been increasing every year. Food waste takes relativity high portion of domestic waste and we have much difficulty in treating it. Most of food wastes are landfilled or incinerated after drying for the reduction of water content. The operation cost of the landfill and the incineration are very high. To solve the landfill and the incineration problems in recent years, the recycling of food waste was used by the methods of turning food waste into animal food and fertilizer. Food wastes are compatible to be used as feedstock of the fermentation because they contain valuable nutrients. Among these situations, organic acids, which are effectively used in a variety of industrial processes, can be considered to be a high cost value-added products. The purpose of this study is to evaluate the possibility of organic acid concentration using a MF/RO system. A MF/RO system was believed to be an effective one for the concentration of organic acid from food waste. Water quality of fermentation broth, MF permeate and RO retentate in terms of conductivity, pH, electric conductivity, TS (Total solids), TDS (Total dissolved solids), CODcr concentration, chloride ion concentration was examined as analytic items. pH of fermentation broth was higher than that of MF permeate and RO retentate due to the concentration of organic acid. pH of RO retentate was about 4. Conductivity, TDS, CODCr and chloride ion of RO retentate were about 1.3, 1.3, 2.9, 4.5 times higher than that of fermentation broth, respectively and TS reduced about 0.8 times. This may be ascribed to separate effectively the solid-liquid separation by MF and RO rejection. Consequently, a MF/RO system is believed to be applicable for the concentration of organic acid from fermentation broth of food waste.
Authors: Hyun Jong Lee, Beom Goo Lee, Dae Yong Shin, Heon Park
Abstract: In this study lignocellulosic fibers, such as kenaf bast, kenaf core, sugar cane bagasse, cotton, coconut coir, and spruce, which are environment friendly natural materials, were tested for their ability to remove copper, nickel and zinc ions from aqueous solutions. The fibers were analyzed for Klason lignin content, water sorption capacity and dry volume. The fiber with the highest level of heavy metal removal in the separate and mixed solution was kenaf bast.. In the mixed solution kenaf bast, sugar cane bagasse and cotton removed more copper and nickel ion than in the separate solution, and the amounts of removed heavy metal ions were changed in some lignocellulosic fibers, compared to those of the separate solution. In the mixed solution heavy metal ions may compete with one another for sorption sites on the surface of lignocellusic fiber. In kenaf bast to remove heavy metal ions most, Klason lignin content was the second lowest, and water sorption and dry volume were the lowest in all tested lignocellulosic fibers. It showed that removal of heavy metal ions does not correlate with any chemical and physical factors, but may be affected by the cell wall structure of lignocellulosic fibers and how many free phenolic groups in lignin, which are considered as the heavy metal ion binding site, are exposed on the surface of fibers. Cotton, with about 1% Klason lignin, was very low in heavy metal ion removal, while all other fibers containing greater than about 10% lignin did remove heavy metal ions. It showed that even the lignin content of lignocellulosic fibers does not correlate with heavy metal ion removal but lignin does play a role in heavy metal ion removal.
Authors: Takanori Watari, Katsuhiro Ogawa, Toshio Torikai, Mitsunori Yada, Masaki Akiyama, Masaki Ida
Abstract: Porous plate with bimodal size distribution was prepared using the molten slag from the incinerator. The slag was pulverized to 1-10μm using a planetary ball mill. On heating the pellet formed with this powder, its relative density at 750°C and 800°C were 70% and 85%, respectively. At 750°C, each particle partially attached together at the contacted point. At 800°C, however, all particles melted, coagulated together and increased their size. The slag powder was granulated using a tumbling granulator, resulting granules of 0.5-5mm size. The compressive strength of the granule sintered at 750°C was 0.39 kgf. The density of the granule decreased by ~60%. The sintered granules were mixed with a proper amount of glass powder and starch water, and the slurry was cast to a mold (φ80mmx10mm). After drying the cast plate, it was heated at 630°C. The density of the plate was 1.2 gcm-3, ~43% of original slag value. The sound absorption coefficients of the plate were 0.02 and 0.4 at 200Hz and 1500Hz, respectively.
Authors: Hoon Cho, Byoung Soo Lee, Hyung Ho Jo
Abstract: The influence of extrusion temperature and Ti content was investigated by observing the microstructure and determining the mechanical strength of A3003 alloy tube. The A3003 alloy was modified by inoculation in terms of addition of Ti and then extruded at the various extrusion temperatures. In case of A3003 alloy tube without addition of Ti, the yield strength was slightly improved with decreasing extrusion temperature. On the other hand, the yield strength was improved markedly in A3003 alloy tube with small addition of Ti, and also ductility was slightly reduced. Grain size distribution from observing the microstructure was different with addition of Ti. Coarse grains were formed on the outer and inner parts of the alloy tube without addition of Ti, whereas the finer grains were uniformly distributed in the alloy tube with addition of Ti. Thus the microstructure and mechanical strength of A3003 alloy tube could be controlled by addition of Ti. Threefore, optimum Ti content and extrusion temperature to fabricate high yield strength and ductility A3003 alloy tube (σy=60 MPa, ε=30%) for eco-friendly refrigerant application are above 0.05wt.Ti and below 480 °C, respectively. Introduction
Authors: Jae Ik Lee, Byung Wan Jo, Yeong Seok Yoo, Kyeong Ho Cheon
Abstract: As a basic stage for developing new construction material utilizing sewage sludge ash, this study is identified by specific material characteristics through XRD, SEM, uniaxial compressive strength, porosity, and the drying shrinkage by manufacturing mortar with sewage sludge ash. The average drying shrinkage of sewage sludge ash mortar aged 7 days showed 88% of the strain of the one aged 28 days. The porosity of sewage sludge ash mortar was about 7~10%. The more quick lime and blast furnace slag were added, the less porosity appeared.
Authors: Il Ho Kim, Won Sik Lee, Se Hyun Ko, Jin Man Jang, Ho Sung Kim
Abstract: The effects of use of open cell Al foam and thermoelectric element in a hydrogen storage system were investigated. Extremely different heat conductivities were observed in two storage systems with or without open cell Al foam. By applying the open cell Al in this hydrogen storage system, the reaction sensitivity of the temperature and equilibrium pressure was far rapidly increased than that without the open cell Al foam. During increasing the temperature by heating element, heating rate of hydride powders was very fast in the storage system including Al foam, while temperature of powders was almost not changed in system without foam. Also, in case of using thermoelectric element, heating and cooling rate was very sensitive in the system with Al foam and heating-cooling cyclic behavior within the system controlled by thermoelectric element is seemed to be satisfied for some applications in industry.
Authors: Se Gu Son, Seong Yeob Hong, Young Do Kim
Abstract: The goal of the present work was investigated development of ET(Environmental Technology) industrial geopolymer materials from mixture Silica Mine Waste(SW) and ground granulated blast furnace slag(GGBFS) and alkali activator solution(sodium silicate) by the Geopolymer Technique at ambient temperature. As for the synthesis of geopolymeric monoliths, four different GGBFS content(10wt%, 20wt%, 30wt%, 40wt%) and three types of GGBFS(GGBFS-1(blaine 4,000cm2/g), GGBFS-2(6,000cm2/g), GGBFS-3(8,000cm2/g)) are investigated to obtain the optimum synthesis condition based on the high compressive strength. The weight ratio between the alkali activator solution and dry mix(SW and GGBFS) were 0.25 and 0.3, respectively. The results showed that geopolymeric monolith containing 30wt% GGBFS exhibits higher compressive strength and increased along with increase of GGBFS blaine. The compressive strengths of GGBFS-1, GGBFS-2 and GGBFS-3 are 66.7MPa, 83.1MPa, 94.1MPa, respectively. Additionally, scanning electron microscope (SEM) techniques are used to characterize the microstructure of the geopolymeric monoliths. SEM observation shows that it is possible to have amorphous aluminosilicate gel and calcite forming simultaneously within monoliths. XRD patterns indicate that geopolymeric monolith is composed of amorphous aluminosilicate phase and calcite and quartz.
Authors: Seong Ho Son, Dae Chol Kwon, Do Won Jeong
Abstract: The purpose of this study is to develop non nitric acid desmut to cope with environment regulation and at the same time, to obtain the effect comparable to nitric acid in removing smut. For this, some desmut solutions were produced adding 2~3 chemical reagents to basic components such as peroxide, ammonium group, ferric group compounds and acid. And, electrochemical treatment was tried to remove ammoniacal nitrogen(NH3-N) in desmut solution after desmut treatment. Consequently, we could gain smut-removing ratio of 90% using the solution mixed with peroxide, ammonium group, ferric group compounds and sulfuric acid at 35°C for 70 seconds, and the ratio is almost the same with that using nitric acid type desmut solution. In this work, most nitrogen(T-N) was confirmed to be ammoniacal nitrogen(NH3-N). In addition, we succeeded in controlling ammonia-nitrogen below 60 ppm corresponding to environment regulation by electrochemical treatment in the wastewater.

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