Papers by Keyword: Cordierite

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Authors: Zhi Juan Gao, Wei Ren Bao, Li Ping Chang, Jian Cheng Wang
Abstract: A Cu-SAPO-34/cordierite monolithic catalyst was prepared by in-situ hydrothermal method. The effects of ultrasonic treatment were mainly investigated during the preparing process. The removal of NOX was evaluated using a fixed-bed reactor. X-ray diffraction, scanning electron microscopy were used to characterize the samples showing that the crystallinity of Cu-SAPO-34 molecular sieve have increased after ultrasonic treatment. The Cu-SAPO-34/cordierite prepared by ultrasonic treatment showed higher de-NOx activity and stronger anti-aging property. NOx conversion could reach more than 80% between 440 and 560°C over the fresh Cu-SAPO-34/cordierite catalyst with ultrasonic treatment (600 W, 2 h) and the highest conversion was 86%, however, the highest conversion was only 76% over the Cu-SAPO-34/cordierite catalyst without ultrasonic treatment. After aging (treated for 15 h at 720 °C in the presence of 200 ppm SO2 and 10% vapor), NOx conversion reached more than 45% between 400 and 520 °C over the catalyst with ultrasonic treatment and the highest conversion was 57%, however, the highest conversion was only 43% over the catalyst without ultrasonic treatment. The XRD and SEM results indicated that the structure and morphology of Cu-SAPO-34/cordierite monolithic catalyst kept in good condition after aging.
Authors: Zhong Dong Tao, Kai Huang, Dong Fang Wu
Abstract: A novel hexaaluminate material Ca0.6La0.4FexMn1-xAl11O19 was prepared by a micro-emulsion method, and then washcoated on the cordierite substrates to produce monolithic catalysts. The obtained hexaaluminates were characterized by X-ray diffraction and scanning electron microscope. Results show that the particles of the prepared hexaaluminates samples are well-proportioned and small, and that the lower-quantity replacement of Mn2+ with Fe3+ is of benefit to forming single hexaaluminates crystal phases. After the partial replacement of Mn2+ with Fe3+ in hexaaluminate, the catalytic activity in methane combustion improved.
Authors: Ping Fu, Zhi Liang Huang, Fang Zhang
Abstract: The cordierite porous ceramics were made from kaolinite, talc and α-alumina, formed by pressing and fired at 1200 °C for one hour. Starch was used as pore-forming agent. Physical/chemical properties and microstructure of products were characterized. The results show that samples exhibit relatively high strength, low coefficient of thermal expansion and well-distributed gradient pores. The pores of samples are homogeneous.
Authors: Taufik Aboud
Abstract: Reagent grade chemicals were used to explore glass formation ability and allocate the glass forming area for the glass system SiO2-P2O5-Al2O3-MgO-Na2O. FT-IR, DTA, DSC and TMA techniques were employed to characterize the obtained glasses. The multicomponent, mixed network glasses, in which AlPO4 tetrahedral units are being incorporated into the network structure through substitution for pairs of SiO4 tetrahedra, exhibit high durability, low thermal expansivity (at Al2O3/P2O5 ˃1), relatively high softening temperatures (at low P2O5 contents) and an increased thermal stability (poor tendency for crystallization). When heated at high temperatures and / or for long periods of time, and depending on their AlPO4 content, together with the Al2O3/P2O5 ratio, the glasses crystallize through a multistage process involving reconstruction and depolymerization of the glasses network structure. The crystallization behavior of many different glasses was investigated, phases identified and characterized, through XRD, and SEM coupled with EDX and X-ray mapping together with optical microscopy. The powder ceramization route had to be used to achieve the devitrification of the glasses with high thermal stability. Berlinite, corundum, spinel, indialite and cordierite among others were the crystallizing phases when different glasses were heated for various times. Microporous materials made of some of these technically favorable minerals, and characterized by an interesting morphologies were obtained, through acid leaching of some of the glass-ceramics produced. It is believed that the glass system under investigation is a fertile one, the crystallization of some glasses within it, represents another fabrication route for obtaining glass-ceramics with specific crystalline phases, as well as microporous materials made of such phase. In both cases, packages of the most suitable properties are obtainable.
Authors: Sen Mei, Juan Yang, José Maria F. Ferreira, Rodrigo Martins
Authors: Richard Dobedoe, D. Holland, W. Hanson
Authors: C. Tardei, G. Gavriliu, Manuela Hagiopol
Authors: A. Gouda, G. Patriarche, Maiken Heim, Doreya M. Ibrahim
Authors: Lim Yi Xuan, Johar Banjuraizah, Zainal Arifin Ahmad
Abstract: α-Cordierite glass ceramic was synthesised through crystallization of glass compacts made of milled glass frits. The effect of temperatures and colorants were studied. The crystal structure of α-cordierite was analysed using X-ray diffraction technique and Rietveld structural refinement method. Density, porosity and shrinkage analysis, Vickers hardness and SEM were also performed. The result revealed that at higher sintering temperatures, the properties of α-cordierite was getting better. Low apparent porosity level and high hardness dense α-cordierite was fabricated at temperature 1350oC. The low porosity level may lead to high thermal conductivity which suggested that cordierite was candidates for FIR therapy instrumemts.________________________________________________________________________
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