11th International Ceramics Congress

Volume 45

doi: 10.4028/www.scientific.net/AST.45

Paper Title Page

Authors: Pio Forzatti, Fabrizio Arosio, Cinzia Cristiani
Abstract: The paper presents an overview of the present status and the perspectives for use of structured catalysts in the power generation, transport and environmental sectors. In particular catalytic combustion of natural gas for the production of energy in gas turbines, abatement of NOx from mobile and stationary sources under lean and stoichiometric conditions, removal of VOC from industrial effluents and soot combustion in the exhaust gases of vehicles are discussed.
Authors: A. Deptuła, J. Chwastowska, Wiesława Łada, T. Olczak, D. Wawszczak, E. Sterlinska, B. Sartowska, K.C. Goretta
Abstract: Hydroxyapatite (HA) microspheres of diameter <70 μm have been synthesized by solgel processing. The starting sols were prepared by ultrasonic mixing of concentrated solutions of calcium acetate (1.7M) with 85% H3PO4, followed by emulsification in dehydrated 2-ethyl-1- hexanol. Drops of emulsion were solidified by extraction of water with this solvent. The final thermal treatment was a 2 h soaking in air at 900°C. Properties such as hydraulic resistance and sedimentation rate, which are important for application in ion-exchangers, were superior for our prepared microspheres in comparison with irregularly shaped commercial HA. Adsorption of the following metals was investigated: U, Zn, Fe, Cu, Ni, Co, Cd, Pb, Mn, Al, Cr, As, Sb, Bi and Mo. Retention was ≈100% for of all the metals studied when pH > 3–4. On average, ≈1/20 moles of metal reacted with 1 mole of HA. Adsorbed metals could be desorbed with efficiencies of 60–90%. In addition, nuclear-waste-saturated beds of HA could be transformed to insoluble ceramics by thermal treatment. The cost of producing HA microspheres was estimated to be comparable to current prices of irregularly shaped commercial hydroxyapatite powders. For radioactive contaminants such as U, for which resorption need not be considered, porous monoliths were produced by use of industrial reagents. The retention capacity was determined to be 30 mg of U per 1 mg of monolith.
Authors: Saburo Sano, Takeshi Fukuda, Yasuo Shibasaki
Abstract: It has been required to change the industrial production processes to low waste emission ones from a view point of environmental issue. In the production of aluminum building materials, large amount of sludge is emitted as industrial waste. If we can change the waste to valuable products, we can respond to the request. Synthesis technology of kaolinitic particles from various starting raw materials had been established at National Industrial Research Institute of Nagoya (NIRIN, present: AIST Chubu). Hydro-thermal treatment is applied to the technology and obtained particles show various shapes such as plate, shell and so on. Collaborative research work between NIRIN and YKK corporation to develop high performance alumina powder form aluminum sludge, a by-product from surface treatment process in the manufacturing of aluminum building materials, had been done by using the fruits from the research project on kaolinite synthesis at NIRIN. As the result, high performance platy alumina powder was developed by using hydro-thermal synthesis technology.
Authors: Wilson Acchar, G.C.L. Silveira, Sonia Regina Homem de Mello-Castanho, Ana M. Segadães
Abstract: The use of industrial waste materials as additives in the manufacture of ceramic products has been attracting a growing interest from researchers in recent years and is becoming common practice. The continued depletion of natural resources throws a new light on the potential use of some industrial wastes and natural sub-products as full-fledged alternative ceramic raw materials. This work describes the research carried out on the low temperature manufacturing of alumina bodies using, as additive, granite reject as-produced by an ornamental stone processing industry that saws granite stones into blocks and slabs in Rio Grande do Norte, Brazil. This reject is produced in significant amounts and is discarded in sedimentation lagoons, landfill areas or simply thrown in rivers, resulting in environmental pollution. Samples containing up to 30 wt% granite reject and 5 wt% manganese oxide (constant) were uniaxially pressed and sintered in air in an electric furnace (1150-1350 °C, for 1 hour). Sintered test pieces were characterized by X-ray diffraction, apparent density, open porosity and flexural strength. The results showed that the addition of granite reject and manganese oxide enables low temperature sintering and remarkably improves the cold mechanical properties of the alumina body.
Authors: F. Raupp-Pereira, M.J. Ribeiro, Ana M. Segadães, Joao A. Labrincha
Abstract: This work describes the studies carried out with various industrial wastes and natural byproducts based on the SiO2-Al2O3-CaO system, aimed at extruding ceramic products of industrial interest. Four waste materials were selected and characterised, namely, (i) Al-rich anodising sludge (A-sludge), (ii) sludge from the filtration/clarification of potable water (W-sludge), (iii) sludge generated in marble sawing processes (M-sludge), and (iv) foundry sand (F-sand). Two different formulations were prepared and bodies were shaped by extrusion, after its detailed optimisation. Screw extruded rods were then fired at several temperatures and characterised in terms of relevant functional properties (shrinkage, density and mechanical strength). Their electrical insulating properties were assessed by impedance spectroscopy. The design of interesting technological properties, such as high electrical and mechanical resistance, refractoriness, etc, was found to be easily achievable by controlling the initial batch formulation and/or the sintering schedule.
Authors: Shuang Shii Lian, Chih Kang Chang, Chin Ching Tzeng
Abstract: The slag from steel plants or incinerators was tried to be recycled and be reused as foam materials through plasma arc melting. The study was intended to investigate the making of foam slag with laboratory plasma melting facilities. The investigated materials consisted of different mixtures of Al2O3、SiO2 、FetO、CaO and Na2O, with the fluxes that were necessary to examine the capability of pore-formation in the solidified ingots. It has been found that the foam slag could be obtained with the proper compositions and conditions of arc heating. The dimensions and distributions of pores were studied and correlated with the temperatures and compositions of slag. The results showed that the sizes of pores inside the solidified ingots were in the range of 1~5 mm, and the thickness of slag was around 20 mm. As to the distributions of the pores in the ingots of slag, further improvement would be needed in the future.
Authors: G. Costa, M.J. Ribeiro, Tito Trindade, Joao A. Labrincha
Abstract: The preparation of ceramic pigments using industrial waste, a galvanizing sludge from the Cr/Ni plating process, as primary source is here reported. The ceramic pigments were prepared using the common solid state reaction process, investigating the optimal formulation, milling and firing conditions. The main focus will be given on the synthesis of chrome-tin red malayaite Ca(Cr,Sn)SiO5 pigment that was fully characterised and then tested in a standard ceramic glaze. Typical working conditions and colour development will be also reported.
Authors: Toyohiko Sugiyama, Hajime Nagae, Kazuo Suzuki, Kenichi Nakano
Abstract: Many kinds of industrial waste were examined as potential constituents of ceramic bricks or tiles. The basic physical properties of these materials were measured, such as sintering temperature, water absorption, porosity, density, color, chemical stability and bending strength. Several kinds of sintered ceramics containing large amounts of waste materials were obtained by adjusting the amount of the waste materials added to the ceramics. These were fired at temperatures lower than 1000°C. A lowering of firing temperature results in a reduction of discharge of CO2 on the production process. Ceramic brick with high water retention is expected to mitigate the heatisland phenomenon by the latent heat of evaporation. Porous ceramics were prepared using industrial waste, burned ash and recycled roofing tile as raw materials. The permeability, water retentivity, water absorption, and other properties of the porous recycled ceramics were investigated. The pF value of the ceramics was measured as an indicator of water retentivity. An appropriate method of characterizing water retentive ceramic materials was also discussed based on results of fundamental examination of the ceramics under practical conditions.
Authors: Y. Pontikes, G.N. Angelopoulus, Ungsoo Kim, H. Lee, William Carty
Abstract: “Bauxite Residue” (BR) is the main waste of alumina-producing Bayer process. With the aim to use BR in the heavy clay industry, the plasticity of clay mixtures with BR was studied by the “High Pressure Annular Shear Cell” (HPASC) technique. The information obtained is cohesion and pressure dependence values that enable the determination of optimal conditions for extrusion. The results for 30wt% BR addition, substituting the clay mixture, demonstrate that the maximum cohesion is increased. Nevertheless, the water demand is increased for achieving the appropriate cohesion and pressure dependence levels for extrusion, a factor that imposes increased demand for drying. By shifting the particle size distribution towards a higher mean particle size, redesigning the clay mixture or by polymer addition, the rheological behaviour of the paste can be adjusted.
Authors: Shao Wei Zhang
Abstract: Carbon-containing refractory bricks are used extensively in the steel industry worldwide. Since the first generation became commercially available in the 1970’s, their processing, microstructures and properties have been improved dramatically, and the service lives of industrial furnaces have thus been extended substantially. In addition to the work on carboncontaining refractory bricks, much effort has been, and is being, made worldwide towards the development of carbon-containing refractory castables. In this paper, the latest R & D towards new generation carboncontaining refractory bricks as well as carbon-containing refractory castables have been highlighted. In the first part, current techniques used to improve mechanical properties of carbon-containing refractory bricks are summarised. A new concept using a catalytic-growth technique to create insitu oxide nanofibres and/or carbon nanotubes in carbon-containing refractory bricks is introduced. The second part addresses some important technical issues of low carbon carbon-containing refractory bricks. Besides the concern about thermal shock resistance, other new problems arising from the use of nanosized carbon, such as the accelerated MgO-C reaction and carbon oxidation, are discussed. In the final part of the paper, technical difficulties hindering the development of carbon-containing castables as well as measures to overcome them are discussed. A novel molten salt synthesis technique developed recently at Sheffield to prepare high quality carbide coatings on graphite is introduced.

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