This study aimed to investigate the feasibility of improving dewaterability and settleability of sewage sludge using coagulation sludge. When mixed with sewage sludge and coagulation sludge at 1:1 ratio, capillary suction time(CST) and specific resistance to filtration(SRF) decreased by about 56% and 68%, respectively. It is found that total solids(TS) and volatile solids(VS) of mixing sludge are increased by about 59% and 53%, respectively. Also, the turbidity of the mixing sludge supernatant was reduced from 99 to 16 NTU. It is observed that the mixing of sewage sludge and coagulation sludge at 1:1 showed better effect than using poly-aluminum chloride(PAC) coagulant at 25 mg/L.

This study investigated phosphorus removal from secondary treated effluent using coagulation-membrane separation hybrid treatment to satisfy strict regulation in wastewater treatment. The membrane separation process was used to remove suspended phosphorus particles after coagulation/settlement. Membrane separation with 0.2 μm pore size of micro filtration membrane could reduce phosphorus concentration to 0.02 mg P/L after coagulation with 1 mg Al/L dose of polyaluminum chloride (PACl). Regardless of coagulant, the residual concentration of phosphorus decreased as the dose increased from 1.5 to 3.5 mg Al/L, while the target concentration of 0.05 mg P/L or less was achieved at 2.5 mg Al/L for the aluminum sulfate (Alum) and 3.5 mg Al/L for PACl. Moreover, alum showed better membrane flux as make bigger particles than PACl. Alum showed a 40% of flux decrease at 2.5 mg Al/L dose, while PACl indicated a 50% decrease of membrane flux even with a higher dose of 3.5 mg Al/L. Thus, alum was more effective coagulant than PACl considering phosphorus removal and membrane flux as well as its dose. Consequently, the coagulation-membrane separation hybrid treatment could be mitigate regulation on phosphorus removal as unsettleable phosphorus particles were effectively removed by membrane after coagulation.

Modified coagulants were investigated for the removal of phosphorus from secondary effluent of wastewater treatment. The modified coagulants were prepared by mixing alkali earth metal ions such as calcium and magnesium. The basicity of a coagulant influenced on the removal of phosphorus, and coagulants with basicity of 5.9% showed a better removal of total phosphorus than that of 38.5%. Also, coagulants with alkali earth metals enhanced the performance of coagulation by 10% and resulted in 67.1% for total phosphorus removal. Moreover, the removal of suspended solids and chemical oxygen demand was improved using coagulants with low basicity and earth metal ions. Results of this study demonstrated that the use of coagulants with low basicity, and calcium and magnesium ions is recommended to improve wastewater effluent quality.

Currently, diopside (MgCaSi2O6) crystal glaze is used frequently for pottery works or in earthen wares, though the process is not straightforward. However, to create and control the positions and sizes of the crystals in desired amounts when making pottery is difficult. To solve this problem, a diopside crystal seed was created at a temperature of 1450˚C. After planting this seed in the glaze, a glaze combination and firing process which allows a user to create crystals with the desired position and at the desired size were established. In addition, in order to investigate the creation process of the crystals, the growth patterns of the crystals were observed and examined using Raman spectrography and XRD and SEM analyses. As a result, the optimum synthesis condition of the diopside seed was created by mixing 1 mole of CaCo3, 0.2 mole of (MgCo3)4(MgCoH)2·5H2O and 2 moles of SiO2 and then applying a firing process to the mixture at 1,450˚C for 30 minutes. The optimum glaze content of the seed was 70 % feldspar, 20 % limestone and 10 % MgCo3. For the firing process, it was confirmed that the size of crystal is larger with a longer firing time at 1100˚C by completing a two-hour process at 1280˚C. In addition, the diopside crystal has columnar structure and is less than 1μm in size.

This is the study on diffusion of ceramic body oxide compounds to glaze. For ceramic bodies, no ferrous oxides contain white ware, celadon, and 3 wt% iron oxides contained white ware was used in this experiment. These ceramic bodies were glazed by transparency glaze, iron oxides contained glaze, and glaze made by pine tree ash that treated in 1240 degree, under reduction condition for an hour. An electron probe microanalyzer(EPMA) was used to study diffusion of oxides and to calculate distance of ceramics bodies. As a result, only iron oxide and magnesium oxide from the body diffused to glaze, and also made a band which shown very thin layer of iron oxide and magnesium oxide between the body and glaze. The densest band of iron oxide formed 100 to 150μm in the glaze, and the densest band of magnesium oxide was found 50 to 100μm in the glaze. Therefore, it could be concluded that iron oxide in the body is diffused to the glaze and it affects the color of glaze, even though iron oxide exists in the glaze. Furthermore, the thickness of the glaze has an effect on the color of celadon.

NiO-doped hibonite pigments were synthesized by the solid state method to get stabilized blue color pigment inboth oxidation and reduction atmospheres. Optimum substitution condition with NiO for hibonite blue pigment was investigated.Experimental results were comparable to those of previous cobalt-minimization studies performed with other phosphate- oroxide-based cobalt-containing ceramic pigments (having olivine (Co2SiO4), spinel (CoAl2O4), or with co-doped willemite((Co,Zn)2SiO4) structures). Composition was designed varying the NiO molar ratio increasing with SnO2. The optimumsubstitution content is 0.93mole NiO with 0.75mole SnO2. The characteristics of the synthesized pigment were analyzed byXRD, Raman spectroscopy, SEM, and UV-vis. Synthesized pigment was applied to a lime-barium glaze with 10wt% each andfired at an oxidation atmosphere of 1250oC/1h and a reducing atmosphere 1240oC/1h. Blue color was obtained with L*a*b*values at 43.39, −6.78, −18.20 under a reducing atmosphere and 41.66, −6.36, −14.7 under and oxidation atmosphere, respectively.

The purpose of this study is to investigate the coloration characteristics by identifying the factor affecting redcoloration of copper red glaze in traditional Korean ceramics. This study analyzed the characteristics of the reduction-firedcopper red glaze by using XRD, Raman spectroscopy, EDX and UV-vis spectroscopy. As a result of XRD analysis, the glazecompletely melted and amorphous glass appeared overall, and the characteristic peak of metal Cu was shown together. Inaddition, as a result of Raman analysis, the characteristic bands of CuO and Cu2O were shown together. The distribution ofcomponent elements was observed by EDX. As a result, copper(Cu) were distributed throughout the glaze. Thus, it was shownthat copper red glaze appeared the best red coloration because metal Cu, CuO and Cu2O evenly existed throughout glaze inparticle colloidal state. The chroma value of the copper red glaze was CIE L* 30.07, a* 13.65, b* 3.72. Wine-Red Solutionwas shown by Dark Graish Red coloration.

First, a purified sludge was calcined at various temperatures viz. 800, 900, 1000, 1100 and 1200˚C per hour. Subsequently 100 wt% of ware from Geryong mountain was mixed with 5~25 wt% of a purified sludge. Then the ware was treated at 1250˚C in an electric kiln to test a bending strength. The physicochemical property of the prepared ware was characterized by XRD, Raman and SEM analysis. Among the different percentage, 25 wt% of a ware in a purified sludge calcined at 1000˚C showed 689 kg/cm2 strength. Also the purified sludge calcined at 1000˚C was adequate physical properties than the other composites. Further to enhance the physical strength, 3 wt% TiO2 (a mineralizer) was added into the ware and the strength was increased up to 731 kg/cm2. The composites exhibit absorption and porosity rates of 0.17% and 0.39% respectively.

Generally, the color gold has had a biased conception due to its traditional use. Thus, this bias has resulted in alack of usage of golden glaze on ceramics and also a lack of extensive studies of such glazes. In this paper, optimum conditionsand mechanism of formation of gold color crystallization glaze containing Fe2O3(hematite), which is developed for gold colorsof ceramic glazes, were studied. Experimental result showed that there are pyroxene based on diopside and TiO2 phase in thebase of a crystallization glaze with a value of TiO2 of 6wt% confirmed by XRD and Raman Spectroscopy. When Fe2O3 wasused as a colorant for the gold color, the TiO2 peak became extinct and the intensity of the diopside peak was sharper. Feldsparof 60wt%, talc of 20wt% and limestone of 20wt% were used as the starting materials and these were tested using a threecomponent system. The best result of test was selected and extended to its vicinity as an experiment to determine TiO2 andFe2O3 contents. The glaze with TiO2 of 6wt% and Fe2O3 of 12wt% addition showed stable pyroxene based diopside crystalsand the development of gold color. This gold color was obtained with CIE-L*a*b* values of 51.27, 4.46, 16.15 (a grayishyellow brown color), which was gained using the following firing conditions: temperature increasing speed 5oC/min, holdingfor 1h at 1280oC, annealing speed 3oC/min till 1100oC, holding for 2h at 1100oC, and finally natural annealing.

Cobalt (Co) compounds have been used for centuries to impart rich blue color to glass, glazes and ceramics. Cobalt monoxide (CoO), an oxide of Co, is an inorganic compound that has long been used as a coloring agent in the ceramic industry. Unlike other coloring agents, CoO can be used to develop colors other than blue, and several factors such as its concentration in the glaze and firing condition have been suggested as possible mechanisms. For example, CoO produces a typical blue color called "cobalt blue" at very low concentrations such as 1 wt% in both oxidation and reduction firing conditions; a higher concentration of CoO (5 wt%) develops a darker blue color under the same firing conditions. Interestingly, CoO also develops a purple color at high concentrations above 10 wt%. In this study, we examined the applicability and mechanism of a novel purple glaze containing cobalt(II, III) oxide, one of the well characterized cobalt oxides. Experimental results show that an Augite crystal isoform (Augite-Fe/Co) in which Fe was replaced with Co is the main component contributing to the formation of the purple color. Based on these results, we developed a glaze using chemically synthesized Augite-Fe/Co crystal as a color pigment. Purple color glaze was successfully developed by the addition of 6~15 wt% of Co3O4 to magnesia lime.

We collected Seokganju minerals (regions in Gyeryong Mountain, Sangsin-ri, Banpo-myeon, GongjuChungcheongnam-province), which were used as natural color pigments for grayish-blue during the 15th~16th centuries of theJoseon era, and investigated their crystallographic features to develop a black pigment having a spinel structure. By a Ramananalysis, the color of Seokganju under transparent glaze as a pigment for painting was black because hematite (Fe2O3) inSeokganju was converted to magnetite (Fe3O4) However, Seokganju into the transparent glaze as a pigment was brown becauseof hematite (Fe2O3) and small amounts of maghemite (γ-Fe2O3) in Seokganju minerals. Only Seokganju mineral is used, it isnot suitable for black pigment into the transparent glaze. This study tried to develop a spinel crystal black pigment stabilizedby Seokganju with CoO, Cr2O3, NiO, and MnO2 at 1280oC. A Raman spectroscopy analysis was performed to verify thepresence of Mn The results showed that it existed as spinel, and two crystal phases CoFe2O4 and MnFe2O4 were mixed.CoFe2O4 spinel has a dark grayish black color and Mn2O4 spinel has a greenish black color, and these two appeared as black.The color of a specimen calcined by adding 6wt% of pigment mixed with 5wt% of MnO2 added to lime glaze was analyzedwith a UV spectrophotometer. When applying the color pigment, it appeared black stabilized with L*24.23, a* 0.12, b* −2.29at 1260oC oxidative calcination, With 1240oC reduction firing, it is appeared black stabilized with low brightness of L* 23.13,a* −1.12, b* 0.54.

The goal of this investigation was to produce a zirconia-family black ceramics that has enhanced functionality andreliability. Color zirconia ceramics have been produced by adding pigments. Pigments cause structural defects within zirconiaand result in a drop in physical properties. Using environmentally friendly rice husk, we produced a black zirconia that is freeof structural defects. In optimal firing conditions for black zirconia the calcining temperatures of the molding product arechanged from 400oC to 1200oC, and the firing temperatures are changed from 1400oC to 1600oC. Color of testing the specimenswas analyzed using Ultraviolet (UV) spectroscopy. Scanning Electron Microscope (SEM), EDAX (EDX), and Fourier transforminfrared spectroscopy (FT-IR) analyses were carried out in order to examine impregnation properties and crystal phases.Universial Test Machine (UTM) was used to measure the flexual strength as well as the compressive strength. Fromexperimental results, it was found that in optimal firing conditions the sample was calcined from 1000oC to 1500oC. Commissioninternationalde I’Edairage (CIE) values of manufactured black zirconia color were L*=29.73, a*=0.23, b*=−2.68. Thebending strength was 918 MPa and the compressive strength was 2676 MPa. These strength values are similar to typicalstrength values of zirconia, which confirms that carbon impregnation did not influence physical properties.

The purpose of this study was to determine the optimal firing condition and composition for Al2TiO5 crystal, which is suitable for stable coloration in glazes at high temperatures, using Cr2O3 as chromophore for the synthesis of Al2TiO5 system pigments. Al2TiO5 has a high refractive index and good solubility of chromophore in the Al2TiO5 lattice, making this structure a good candidate for the development of new ceramic pigments. Pigments were synthesized by using Al2O3 and TiO2 mainly. Various amounts of Cr2O3 such as 0.01, 0.02, 0.03, 0.04 and 0.05 mole were also added. Each compound was synthesized at 1300˚C, 1400˚C, and 1500˚C for 2 hours and cooled naturally. The crystal structure, solubility limit, and color of the synthesized pigments were analyzed by XRD, SEM, Raman spectroscopy, UV and UV-vis. The changes in color as the result of applying 6 wt% of the synthesized pigments to lime barium glaze were expressed as CIE-L*a*b* values. A Cr2O3 0.03 mole doped Al2TiO5 brown pigment was successfully synthesize at 1400˚C, and the values of CIE-L*a*b* parameters were L* = 44.62, a* = 3.10, and b* = 17.25. In the case of the pigment synthesized at 1500˚C, the brown color was obtained at 0.01 mole and 0.02 mole Cr2O3, and the CIE-L*a*b* values were 55.34, 1.73, 28.64, and 49.39, 0.51, 21.33, respectively. At 1500˚C, the maximum limit of solid solution was 0.03 mole Cr2O3. The glazed sample showed green color, and the values of the CIEL* a*b* parameters were L* = 45.69, a* = -0.98, and b* = 20.38.

Al2TiO5 has a high refractive index and good solubility of the chromophore in the Al2TiO5 lattice, which allowsthis structure to be a good candidate for the development of new ceramic pigments. However, pure Al2TiO5 is well knownto decompose on firing at 900~1100oC. However, this process can be inhibited by the incorporation of certain metal cationsinto its crystalline lattice. In this study, the synthesis of gray ceramic pigment was performed by doping cobalt on the Al2TiO5crystal structure. The Al2TiO5 was synthesized using Al2O3 and TiO2, and doped with Co3O4 as a chromophore material. Inorder to prevent the thermal decomposition during the cooling procedure, MgO was added to samples by 0.05mole, 0.1mole,and 0.15mole as a stabilizer. The samples were fired at 1500oC for 2 hours and cooled naturally. The crystal structure, solubilitylimit, and color of the synthesized pigment were analyzed using XRD, Raman spectroscopy, UV, and UV-vis. Al2O3 wasavailable for the formation of CoAl2O4, which should also be considered in order to explain the small amount of this phasedetected in the sample with the higher Co2+ content (≥0.03mole). It was found that the solubility limit of Co2+ in the Al2TiO5crystal was 0.02mole% through an analysis of Raman spectroscopy. Through the addition of a pigment with 0.02mole% ofCo2+ to lime-barium glaze, stabilized gray color pigments with 66.54, −2.35, and 4.68 as CIE-L*a*b* were synthesized.

Ceramic pigments were developed by using 4 kinds of Brass scraps. Each Brass scraps were mixed with same weight-ratio of Husk ash, and fine-ground by Rotate ring mill(RRG-120, Armstech industrial. co. Ltd, Korea) after firing at 900℃, 1000℃ and 1100℃. As a result, analysis of particle size of synthetic pigments by particle size analyser, they are 3μm as average. The resulting pigments were characterized by using XRD, FT-IR, SEM Structure of the crystals are Zn2SiO4,, and ZnO, Cu2O, CuO, and cristobalite are existed and particles' shape are plate or needle. As a result of analysis of chemical composition by XRF, synthetic pigments have high SiO2 and CuO content and have SnO2, ZnO and NiO, too. 1wt%, 3wt% and 5wt% pigments were added in each lime glaze, lime-barium glaze and lime-magnesia glaze, and fired at oxidation and reducing atmosphere to figure hue in glazes out. As a result of analysis of color, chroma and brightness by UV, colors of glazes fired at oxidation atmosphere turned into green from sky blue, and colors of glazes fired at reducing atmosphere turned into pink and red.

The purpose of this study is to identify the best firing condition for Celadon, which is one of the famous traditional pottery to represent Korean culture, by minimizing energy consumption, cutting firing time, shortening the time of processing ceramic making, in order to, save energy as well as to protect the potters' health. Most Korean potter starts their reduction from 950℃ to change kiln atmosphere. However on this study, reduction have started from 950℃ to 1200℃ by increasing 50℃ at a time. Then the results are analyzed to be compared to previous Celadon, in colors, chroma, and brightness. As a results, it is found, that the best temperature for starting reduction is 1100℃, when chroma and brightness values to meet same with previous celadon. Therefore the best condition could be made by starting the reduction on 1100℃ to fire celadon, which would have shorten 2 hours of firing process and, at the same time, it could have saved the energy by 12%.

OXI-PAN fibers, Kynol fibers and rayon fibers were used as precursorsfor the preparation of activated carbon fibers (ACFs) by chemical activation with KOH at 800℃. The effects of different precursorfibers and fiber/KOH ratios on the final ACFs are discussed. The precursor fibers used are appropriate for the ACFs in a single stage pyrolysis process. The OXI-PAN fibers which were activated with KOH of 2.0M showed a specific surface area of 2328m2/g however, loosed the fiber shape because of low yields. The Kynol fibers and Rayon fibers showed the high yields but the lower specific surface area of 900m2/g and 774m2/g, respectively, at KOH of 1.5M. The OXI-PAN fibers which were activated with KOH of 1.5M have a specific surface area of 1028m2/g and higher micro-pore volumes and lower yields rather than Kynol-1.5 and Rayon-1.5 samples. This phenomenon is because of higher chemical resistance of the Kynol and Rayon fibers rather than OXI-PAN fibers. However, the Kynol fibers were the best precursors on KOH activation at 800℃ considered carbon yields, surface areas and micropore volumes.

Recycling of incineration ash generated from domestic waste incinerators is important from environmental and energy conversation aspects. The main components of bottom ash are CaO, Al2O3, SiO2, P2O5, MgO, and Fe2O3, similar to geological components. However, it also contains heavy metal ions such as Cu2+, Pb2+, and Cr6+. The ash material was sintered at 1100 ~ 1150oC by adding pink kaolin to stabilize those heavy metals. The study analyzed the crystal phase and absorption rates of the sintered material for application as a sub-base layer material for roads and conducted tests for the requirements for sub-base layer materials for roads, such as CBR test, quantity of abrasion, and liquid limit. Considering the plasticity, water absorption, and compressive strength of the road base, the mixture with 76wt% bottom ash and 24wt% pink kaolin after sintering at 1,120oC, showed CBR test result of 33.0, quantity of abrasion of 30.3, and liquid limit of NP (no plasticity). These result indicated the possibility of using bottom ash as a sub-base layer material, which satisfied requirements of the standard specification for road construction.