DOCSLIB.ORG

Technological Properties of High Alumina Refractories with Different

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Technological Properties of High Alumina Refractories with Different Shalaby et al. Bulletin of the National Research Centre (2018) 42:24 Bulletin of the National https://doi.org/10.1186/s42269-018-0030-5 Research Centre RESEARCH Open Access Technological properties of high alumina refractories with different phosphoric acid contents Basel Nour El-Din Ali Shalaby1* , Mohamed Saad El-Maghraby2 and Ali Ismail Mohamed Ismail1 Abstract Background: High alumina refractory batches were prepared from Egyptian clay and imported China calcined bauxite. Three concentrations of phosphoric acid 3, 5, and 7%, were added to study their effects on some of their technological properties. Designed batches tend to form a composition of 76% alumina and ~ 17% silica in addition to the other fluxing and alkali oxides. Chemical and mineralogical composition as well as density and plasticity of both clay and calcined bauxite was performed. Results: Three batches of different phosphoric acid concentrations were fired at 1350 °C for 1 h. Densification parameters of the fired batches as well as the cold crushing strength and thermal shock resistance were carried out. The mineral composition and microstructure of the selected batch were done using XRD as well as SEM and EDAX. It is concluded that by increasing phosphoric acid percentages, the porosities slightly increase and the cold crushing strengths drastically decrease; however, densities and shrinkages exhibit no remarked effects. Conclusions: The mineral composition of the selected fired batch exhibits mullite as a main phase with subordinate amount of corundum, while berlinite, quartz, and cristobalite are in less frequent contents. Microstructure of the selected batch ensures that mullite and corundum are the main mineral phases, in addition to minor phases of phosphate minerals. The fluxing and alkali oxides together with some alumina and silica form a liquid phase, which is responsible for the densification of the batch, while mullite and corundum are the essential formed minerals. Keywords: Egyptian clay, High alumina refractories, Mullite, Corundum, Phosphoric acid Introduction clay mineral (Al2O3·2SiO2·2H2O), e.g., kaolins, fireclays, Refractory materials are inorganic, non-metallic, and and ball clays. In addition, calcined Al2O3-rich raw brittle crystalline solid materials, fired at optimum materials are added to increase the alumina content temperature according to their uses. They are used as and their refractory quality. The additives are mainly face- and back-linings of industrial furnaces at high bauxite (Al2O3·2H2O) and gibbsite (Al(OH)3). These temperature for thermal insulations. They are classi- refractories include fireclay (25–45% Al2O3), aluminous fied according to their chemical composition and fireclay (45–65% Al2O3), and high-alumina (> 72% Al2O3), resistance to attack by the fired materials in contact respectively (Chesters 1974); Kingrey et al. 1976, and Sadik under service conditions into acidic, neutral, and basic et al. 2014). Refractory oxides encompass a broad range of refractories (Shaw 1972 and Chesters 1973). unary, binary, and ternary ceramic compounds that can be Aluminosilicate refractories, rich in silica, are belong- used in structural, insulating, and other applications. ing to acidic refractories, while those rich in alumina Kaolinitic clays are considered as acidic refractories are essentially of neutral type. They are manufactured due to their Al2O3/SiO2 ratio, as well as their limited using refractory clays, which are composed of kaolinite total fluxing and alkali oxide contents, namely, Fe2O3, TiO2,CaO,MgO,Na2O, and K2O. These clays include * Correspondence: [email protected] fireclays, ball clays, and kaolins (Grim 1968). Konta 1Geological Sciences Department, National Research Centre, P.O. 12622, 33 El Buhouth St. Dokki, Giza, Egypt (1979) classified the kaolintic clays for ceramic indus- Full list of author information is available at the end of the article tries according to their content of the total coloring © The Author(s). 2018 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. Shalaby et al. Bulletin of the National Research Centre (2018) 42:24 Page 2 of 7 oxides,i.e.Fe2O3 and TiO2, into two categories; the porosity, and linear shrinkage as well as cold crushing first grade (Seger 1 clays) contains less than 1.2% of the strength and thermal shock resistance were carried out. coloring oxides, e.g., China clay, which is suitable for production of white-ware ceramics, e.g., porcelain Methods tableware and electrical insulators. Clays rich in kaolin- Egyptian clay of Al-Ogybabe area, northeast of Aswan ite containing higher than 1.2% of total Fe2O3 and TiO2 city, south of Egypt, and imported calcined bauxite are classified as Seger 2 clays, which are adequate for were used to produce batch of high alumina refractor- manufacturing colored and heavy clay-based ceramics ies (> 72% Al2O3). The starting materials were received and aluminosilicate refractories. The Egyptian kaolins from Normatic Co. for building materials and refract- and fireclays are mainly belonging to Seger 2 kaolinitic ories, Helwan, Cairo, Egypt. Phosphoric acid of 85% clays (Carniglia and Barna 1992,Routschka2004,and concentration was received from El-Gomhoryia Company Elmaghraby and Ismail 2016). for chemicals. Phosphoric acid reacts with metal oxides to form High alumina refractory > 72% Al2O3 was proc- salts which function as a bonding agent. Phosphoric essed using Egyptian raw clays and calcined bauxite. acid and aluminum hydroxide react readily but alu- Calcined bauxite and Egyptian clay were crushed, mina and phosphoric acid are only slowly reactive at ground to pass through 200 mesh. The used clay ordinary temperature. When temperature rises, phos- acts as a plastic-bonding material for the refractory phoric acid undergoes dehydration and reacts with alu- batch. High alumina refractories were produced as mina to form mono aluminum phosphate, which starts standard from the corresponding calcined bauxite above 127 °C and continues till 427 °C. Between 732 and clay by mixing with different percentages (3, 5, and 1327 °C, aluminum orthophosphate is formed. and 7%) of 85% phosphoric acid concentration, Aluminum orthophosphate resembles silica in struc- semi-dry, pressed, and dried. They were then fired ture. It corresponds to quartz to form berlinite; it has for 1 h at 1350 °C. ortho-polymorphs of cristobalite and tridymite forms Chemical and mineralogical compositions of the (Schacht 2004, Sahnoun and Bouaziz 2012,andLuza starting materials were carried out using XRF and et al. 2015). Refractory concretes based on binder XRD, while the phase composition of the selected modified with orthophosphoric acid improve the batch was done by using XRD and scanning electron thermo-mechanical and physicochemical properties microscope as well as EDAX. (Trepalina et al. 2016). The amount of water that rendered the raw clay The scope of the present research is to prepare high material plastic (i.e., plasticity) was determined using alumina batch using Aswan clay and China calcined the Atterberg method (BS 1377 1975). Bulk densities bauxite as well as to study the effect of different of the calcined bauxite and the clay raw material were phosphoric acid percentages on the technological determined. Densification parameters of the fired properties of the fired samples, through monitoring high alumina batch were investigated as bulk density the densification parameters, cold crushing strengths, and apparent porosity using the water displacement and thermal shock resistance. To achieve these pa- (Archimedes) method according to European Stand- rameters, chemical and mineralogical compositions of ard No. BS En No. 993-1/1993 (Serry et al. 2006). the starting materials were determined using XRF and XRD, respectively. The plastic and liquid limits as well as the plasticity of the clay were determined to Table 1 Chemical composition of the used materials detect the amount of water required for making the Oxide % Clay Calcined bauxite clay as plastic material. The density of the used clay SiO2 52.97 7.20 and the calcined bauxite was also measured. The high Al2O3 29.07 85.39 alumina batch was designed from the Egyptian clay TiO2 1.48 4.08 and the China calcined bauxite according to their Fe O 3.92 2.45 composition. Three different concentrations of 3, 5, 2 3 CaO 0.50 0.07 and 7% of phosphoric acid were added to the pre- formed high alumina batch to form three different MgO 0.20 0.16 concentration batches. The designed batches of differ- Na2O 0.06 0.02 ent phosphoric acid concentrations were fired at K2O 0.28 0.27 1350 °C for 1 h. The phase composition of the SO3 0.76 – selected batch was done using XRD and a scanning LOI 10.62 – electron microscope as well as EDAX. The densifica- Total 99.86 99.64 tion parameters in terms of bulk density, apparent Shalaby et al. Bulletin of the National Research Centre (2018) 42:24 Page 3 of 7 Fig. 1 XRD pattern of the raw clay material Thermal shock resistance at 1000 °C in terms of The calcined bauxite is used to enrich, adequately, the number of heating and coaling cycles was deter- these refractories; it is composed of Al2O3 up to mined using an air-quenching technique. Cold 85.39%, as well as 7.20% SiO2 and nearly 7.0% total im- crushing strengths of the fired bricks were also per- purity oxides (Fe2O3,TiO2,CaO,MgO,Na2O, and formed to detect the maximum load-bearing capacity K2O). XRD patterns of the raw clay and calcined baux- of the batch. ite materials (Figs. 1 and 2) show that clay is composed mainly of kaolinite and halloysite as clay minerals in Results addition to quartz as a non-clay mineral.
Load more

Recommended publications
  • Phase Evolution of Ancient and Historical Ceramics
    EMU Notes in Mineralogy, Vol. 20 (2019), Chapter 6, 233–281 The struggle between thermodynamics and kinetics: Phase evolution of ancient and historical ceramics 1 2 ROBERT B. HEIMANN and MARINO MAGGETTI 1Am Stadtpark 2A, D-02826 Go¨rlitz, Germany [email protected] 2University of Fribourg, Department of Geosciences, Earth Sciences, Chemin du Muse´e 6, CH-1700 Fribourg, Switzerland [email protected] This contribution is dedicated to the memory of Professor Ursula Martius Franklin, a true pioneer of archaeometric research, who passed away at her home in Toronto on July 22, 2016, at the age of 94. Making ceramics by firing of clay is essentially a reversal of the natural weathering process of rocks. Millennia ago, potters invented simple pyrotechnologies to recombine the chemical compounds once separated by weathering in order to obtain what is more or less a rock-like product shaped and decorated according to need and preference. Whereas Nature reconsolidates clays by long-term diagenetic or metamorphic transformation processes, potters exploit a ‘short-cut’ of these processes that affects the state of equilibrium of the system being transformed thermally. This ‘short-cut’ is thought to be akin to the development of mineral-reaction textures resulting from disequilibria established during rapidly heated pyrometamorphic events (Grapes, 2006) involving contact aureoles or reactions with xenoliths. In contrast to most naturally consolidated clays, the solidified rock-like ceramic material inherits non-equilibrium and statistical states best described as ‘frozen-in’. The more or less high temperatures applied to clays during ceramic firing result in a distinct state of sintering that is dependent on the firing temperature, the duration of firing, the firing atmosphere, and the composition and grain-size distribution of the clay.
    [Show full text]
  • Synthesis of Hexacelsian Barium Aluminosilicate by Film Boiling Chemical Vapour Process C
    Synthesis of hexacelsian barium aluminosilicate by film boiling chemical vapour process C. Besnard, A. Allemand, P. David, Laurence Maillé To cite this version: C. Besnard, A. Allemand, P. David, Laurence Maillé. Synthesis of hexacelsian barium aluminosilicate by film boiling chemical vapour process. Journal of the European Ceramic Society, Elsevier, In press, 10.1016/j.jeurceramsoc.2020.02.021. hal-02494032 HAL Id: hal-02494032 https://hal.archives-ouvertes.fr/hal-02494032 Submitted on 28 Feb 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Synthesis of hexacelsian barium aluminosilicate by film boiling chemical vapour process C. Besnard1, A. Allemand1-2, P. David2, L. Maillé1* 1University of Bordeaux, CNRS, Safran, CEA, Laboratoire des Composites ThermoStructuraux (LCTS), UMR 5801, F-33600 Pessac 2CEA Le Ripault, F-37260, Monts * Corresponding author, email address: [email protected] Abstract An original oxide/oxide ceramic-matrix composite containing mullite-based fibers and a barium aluminosilicate matrix has been synthesized by the film boiling chemical vapour infiltration process. Alkoxides were used as liquid precursors for aluminum, silicon and barium oxides. The structure and microstructure of the oxide matrix were characterized by Scanning Electron Microscopy, Energy Dispersive Spectroscopy and X-ray diffraction.
    [Show full text]
  • Synthetic Mullite Precursors: Preparation, Structure, and Transformation Behaviour
    Synthetic Mullite Precursors: Preparation, Structure, and Transformation Behaviour Habilitationsschrift zur Erlangung der Lehrbefugnis für das Fachgebiet Materialwissenschaften an der Gemeinsamen Fakultät für Bergbau, Hüttenwesen und Maschinenwesen der Technischen Universität Clausthal vorgelegt von: Martin Schmücker Deutsches Zentrum für Luft- und Raumfahrt (DLR) Institut für Werkstoff-Forschung 51147 Köln 2003 2 Vorwort Die vorliegende Habilitationsschrift "Synthetic Mullite Precursors: Preparation, Structure, and Transformation Behaviour" basiert auf meinen Arbeitsschwerpunkten "Struktur nichtkristalliner Aluminiumsilikate" und "Frühstadien der Mullitbildung". Diese Themenbereiche habe ich -neben verschiedenen anderen Aktivitäten- während meiner 10-jährigen Tätigkeit im Institut für Werkstoff-Forschung des DLR konzeptionell entwickelt und kontinuierlich bearbeitet. Die Untersuchungen zur Struktur nichtkristalliner Aluminiumsilikate erfolgten zusammen mit internationalen Kooperationspartnern sowie im Rahmen des DFG-Sonderforschungsbereichs 408 (Anorganische Festkörper ohne Translationssysmmetrie, Univ. Bonn). Während diese Arbeiten überwiegend grundlagenorientiert waren, war der Hintergrund für meine Untersuchungen zur Mullitbildung stärker anwendungsbezogen: Der Einsatz von mullitbasierter Hochleistungskeramik z. B. für thermisch exponierte Bauteile im Bereich von Luftfahrt, Raumfahrt und Antriebstechnik setzt ein tieferes Verständnis der Mullitbildungsmechanismen voraus. Es zeigte sich, daß die Arbeiten zur Mullitbildung und zur Struktur
    [Show full text]
  • This Dissertation Has Been 62—2136 M Icrofilm Ed Exactly As Received GIELISSE, Peter Jacob M., 1934- INVESTIGATION of PHASE EQ
    This dissertation has been 62—2136 microfilmed exactly as received GIELISSE, Peter Jacob M., 1934- INVESTIGATION OF PHASE EQUILIBRIA IN THE SYSTEM ALUMINA-BORON OXIDE-SILICA. The Ohio State University, Ph.D., 1961 M ineralogy University Microfilms, Inc., Ann Arbor, Michigan INVESTIGATION OP PHASE EQUILIBRIA IN THE SYSTEM ALUMINA-BORON OXIDE-SILICA DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of the Ohio State University By Peter Jacob M. Gielisse, M. S. The Ohio State University 1961 Approved by Adviser Department of Mineralogy ACKNOWLEDGMENTS The writer wishes to extend his sincere thanks to the many people without whose help the preparation of this dissertation would have been impossible. He is indebted in particular to his adviser, Dr. Wilfrid R. Foster, for his invaluable aid, advice and many kindnesses; to the other members of the faculty of the Department of Mineral ogy, Drs. Ernest G. Ehlers, Henry E. Wenden, and Rodney T Tettenhorst; and to his friend and colleague, Thomas J. Rockett. Acknowledgment is also made for financial support re­ ceived under contract No. AF 33(616)-3189, sponsored by Aeronautical Research Laboratories, Air Force Research Division, Wright Patterson Air Force Base, Ohio; as well as for aid received through a Mershon National Graduate Fellowship awarded to the writer by the Mershon Committee on Education in National Security for 1960-‘61'. It goes without saying that he is also most grate­ ful to his wife, Anna, for her excellent help and encour­ agement over the years. TABLE OF CONTENTS Page INTRODUCTION ......................................
    [Show full text]
  • Kyanite and Related Minerals
    KYANITE AND RELATED MINERALS (Data in metric tons unless otherwise noted) Domestic Production and Use: In Virginia, one firm with integrated mining and processing operations produced an estimated 85,000 tons of kyanite worth $30 million from two hard-rock open pit mines and synthetic mullite by calcining kyanite. Two other companies, one in Alabama and another in Georgia, produced synthetic mullite from materials mined from four sites; each company sourced materials from one site in Alabama and one site in Georgia. Synthetic mullite production data are withheld to avoid disclosing company proprietary data. Commercially produced synthetic mullite is made by sintering or fusing such feedstock materials as kyanite, kaolin, bauxite, or bauxitic kaolin. Natural mullite occurrences typically are rare and not economical to mine. Of the kyanite-mullite output, 90% was estimated to have been used in refractories and 10% in other uses, including abrasive products, such as motor vehicle brake shoes and pads and grinding and cutting wheels; ceramic products, such as electrical insulating porcelains, sanitaryware, and whiteware; foundry products and precision casting molds; and other products. An estimated 60% to 70% of the refractory use was by the iron and steel industries, and the remainder was by industries that manufacture cement, chemicals, glass, nonferrous metals, and other materials. Andalusite was commercially mined from an andalusite-pyrophyllite-sericite deposit in North Carolina and processed as a blend of primarily andalusite for use
    [Show full text]
  • High Pressure Behavior of Mullite-Type Oxides: Phase Transitions, Amorphization, Negative Linear Compressibility and Microstructural Implications
    UNLV Theses, Dissertations, Professional Papers, and Capstones 5-1-2015 High Pressure Behavior of Mullite-Type Oxides: Phase Transitions, Amorphization, Negative Linear Compressibility and Microstructural Implications Patricia Kalita University of Nevada, Las Vegas Follow this and additional works at: https://digitalscholarship.unlv.edu/thesesdissertations Part of the Ceramic Materials Commons, Condensed Matter Physics Commons, and the Engineering Science and Materials Commons Repository Citation Kalita, Patricia, "High Pressure Behavior of Mullite-Type Oxides: Phase Transitions, Amorphization, Negative Linear Compressibility and Microstructural Implications" (2015). UNLV Theses, Dissertations, Professional Papers, and Capstones. 2369. http://dx.doi.org/10.34917/7645928 This Dissertation is protected by copyright and/or related rights. It has been brought to you by Digital Scholarship@UNLV with permission from the rights-holder(s). You are free to use this Dissertation in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s) directly, unless additional rights are indicated by a Creative Commons license in the record and/or on the work itself. This Dissertation has been accepted for inclusion in UNLV Theses, Dissertations, Professional Papers, and Capstones by an authorized administrator of Digital Scholarship@UNLV. For more information, please contact [email protected]. HIGH PRESSURE BEHAVIOR OF MULLITE-TYPE OXIDES: PHASE TRANSITIONS, AMORPHIZATION, NEGATIVE LINEAR COMPRESSIBILITY AND MICROSTRUCTURAL IMPLICATIONS by Patricia E. Kalita Bachelor of Sciences in Physics University of Nevada Las Vegas 2006 Master of Sciences in Physics University of Nevada Las Vegas 2008 A dissertation submitted in partial fulfillment of the requirements for the Doctor of Philosophy – Physics Department of Physics and Astronomy College of Sciences Graduate College University of Nevada, Las Vegas May 2015 Copyright by Patricia E.
    [Show full text]
  • Development and Properties of New Mullite Based Refractory Grog
    materials Article Development and Properties of New Mullite Based Refractory Grog David Zemánek 1,2 , Karel Lang 2, Lukáš Tvrdík 2, Dalibor Všianský 3, Lenka Nevˇrivová 1,2, Petr Štursa 2,3, Pavel Kováˇr 3, Lucie Keršnerová 3 and Karel Dvoˇrák 1,* 1 Faculty of Civil Engineering, Brno University of Technology, Veveˇrí 331/95, 602 00 Brno, Czech Republic; [email protected] (D.Z.); [email protected] (L.N.) 2 P-D Refractories CZ JSC, Nádražní 218, 679 63 Velké Opatovice, Czech Republic; [email protected] (K.L.); [email protected] (L.T.); [email protected] (P.Š.) 3 Department of Geological Sciences, Faculty of Science, Masaryk University, Kotláˇrská 267/2, 602 00 Brno, Czech Republic; [email protected] (D.V.); [email protected] (P.K.); [email protected] (L.K.) * Correspondence: [email protected]; Tel.: +420-54114-7511 (ext. 8067) Abstract: The presented study is focused on optimization and characterization of a high-alumina refractory aggregate based on natural raw materials—kaolins, claystone, and mullite dust by-product (used to increase the alumina and mullite contents, respectively). In total, four individual formulas with the Al2O3 contents between 45 and 50 wt.% were designed; the samples were subsequently fired, both in a laboratory oven and an industrial tunnel furnace. The effects of repeated firing were examined during industrial pilot tests. Mineral and chemical compositions and microstructures, of both the raw materials and designed aggregates, were thoroughly investigated by the means of X-ray fluorescence spectroscopy, powder X-ray diffraction, and optical and scanning electron microscopies.
    [Show full text]
  • Effect of Talc in Mixtures with Fly Ash on Sintering Crystalline Phases and Porosity of Mullite-Cordierite Ceramics
    minerals Article Effect of Talc in Mixtures with Fly Ash on Sintering Crystalline Phases and Porosity of Mullite-Cordierite Ceramics Marta Valášková 1,* , Veronika Blah ˚ušková 1, Alexandr Martaus 1, So ˇnaŠtudentová 2, Silvie Vallová 1,2 and Jonáš Tokarský 1,3 1 Institute of Environmental Technology, CEET, VSB-Technical University of Ostrava, 17. listopadu 2172/15, 708 00 Ostrava, Czech Republic; [email protected] (V.B.); [email protected] (A.M.); [email protected] (S.V.); [email protected] (J.T.) 2 Department of Chemistry, VSB-Technical University of Ostrava, 17. listopadu 2172/15, 708 00 Ostrava-Poruba, Czech Republic; [email protected] 3 Nanotechnology Centre, CEET, VSB-Technical University of Ostrava, 17. listopadu 2172/15, 708 00 Ostrava-Poruba, Czech Republic * Correspondence: [email protected]; Tel.: +420-597-327-308 Abstract: The effect of talc in the two mixtures with the representative sample of fly ash (Class F) was investigated at sintering temperatures of 1000, 1100, and 1200 ◦C. X-ray diffraction, thermal DTA/TGA, and mercury intrusion porosimetry analyses were applied to characterize the mineral phase transformation of talc and fly ash in cordierite ceramic. The influence of iron oxide on talc transformation to Fe-enstatite was verified by the simulated molecular models and calculated XRD patterns and the assumption of Fe-cordierite crystallization was confirmed. The fly ash mixtures ◦ ◦ with 10 mass% of talc in comparison with 30 mass% of talc at 1000 C and 1100 C showed higher linear shrinkage and lower porosity. At a temperature of 1200 ◦C, sintering expansion and larger Citation: Valášková, M.; Blah ˚ušková, pores in mullite and cordierite ceramics also containing sapphirine and osumilite demonstrated V.; Martaus, A.; Študentová, S.; that magnesium in FA and Tc structure did not react with the other constituents to form crystalline Vallová, S.; Tokarský, J.
    [Show full text]
  • Kyanite and Related Materials
    KYANITE AND RELATED MATERIALS By Michael J. Potter Domestic survey data and tables were prepared by John G. Durand, statistical assistant, and the world production table was prepared by Ronald L. Hatch, lead international data coordinator. Kyanite, andalusite, and sillimanite are anhydrous Production aluminosilicate minerals with the same chemical formula (Al2SiO5) but different crystal structures and physical Kyanite Mining Corp. operated two open pit mines in properties. When calcined at high temperatures (in the 1,400o C Buckingham County, VA, and beneficiated the ore into to 1,500o C range for kyanite and andalusite and 1,550o C to marketable kyanite. Some of the kyanite was calcined for 1,625o C for sillimanite), these minerals are converted to mullite conversion into mullite. Company data are proprietary, but (Al6SiO13) and silica (SiO2) (Harben, 1999). Mullite is a Dickson (2000) has estimated U.S. output to be about 90,000 refractory material. During calcination, 1 metric ton (t) of t/yr valued at approximately $13.4 million (before any material aluminosilicate concentrate yields about 0.88 t of mullite. was converted to mullite), using a value of $149 per metric ton, Synthetic mullite is made by heating mixtures of bauxite and the lowest value listed in table 1. High-temperature sintered kaolin or alumina and silica at about 1,550o C to 2,000o C synthetic mullite, made from calcined bauxitic kaolin and (Roskill Information Services Ltd., 1990). known as one of the company’s Mulcoa products, was In 2000, the United States, at an estimated 90,000 t, produced by C-E Minerals, Inc., near Americus, GA.
    [Show full text]
  • Comparative Characterization of Both Alumina and Mullite Matrix Composites Manufactured Combining Filament Winding and Freeze Gelation Processes
    IOSR Journal of Engineering (IOSRJEN) www.iosrjen.org ISSN (e): 2250-3021, ISSN (p): 2278-8719 Vol. 08, Issue 5 (May. 2018), ||VII|| PP 08-20 Comparative Characterization of both Alumina and Mullite Matrix Composites Manufactured Combining Filament Winding and Freeze Gelation Processes Thays Machry1*; Christian Wilhelmi2; Prof. Hazim Ali Al-Qureshi3; Prof. 4 Carlos Perez Bergmann 1Airbus SAS, Hamburg, Germany 2 Airbus Defense and Space, Friedrichshafen, Germany 3 Federal University of Santa Catarina (UFSC), Florianópolis, Brazil 4Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil Corresponding Auther: Thays Machry Abstract: Filament winding and freeze gelation technique are combined in this work to manufacture all-oxide ceramic matrix composites with different matrices.Alumina and mullite are used in combination with a silica sol to manufacture two ceramic suspensions. Fiber infiltration and lay-up is conducted with NextelTM 610 fiber with 3000 denier(organic sized)using the filament winding process. After lay-up the composite is submitted to subzero temperatures forcing the consolidation of the ceramic matrix. The combination of these processing routes is successfully implemented to build up cost-efficient composites.Homogeneous impregnation of the fiber with both ceramic suspensions is achieved. Use of different ceramic fillers influenced, however,porosity formation in the material and consequently its mechanical performance. Interlaminar shear and bending strength of composites with mullite filler are lower than
    [Show full text]
  • A New Silicate Mineral with 14Er Single Chain
    Zeitschrift fUr Kristallographie 200, 115 -126 (1992) by R. Oldenbourg Verlag, Miinchen 1992 - 0044-2968/92 $ 3.00 + 0.00 Liebauite, Ca3CusSi9026: A new silicate mineral with 14er single chain M. H. Z611er*, E. Tillmanns** Mineralogisches Inslilul dcr Universitiit, D-8700 Wiirzburg, Federal Republic of Germany and G. Hentschel Plilznerslr. 5, D-6200 Wiesbaden, Federal Republic of Germany Dedicated to Prof Dr. F. Liebau on the occasion olhis 65th birthday Rcccived: June 19, 1991 Liebauite / New mineral/Calcium copper silicate / 14er single chain Abstract. The new calcium copper silicate liebauite has been found in cavities of a mudstone xenolith from the Sattelberg scoria cone near Kruft in the Eifel district, Germany. It occurs as bluish-green transparent crystals with a vitreous lustre and a Mohs hardness between 5 and 6. The analytical formula for liebauite based on 26 oxygen atoms is Ca2.99Cu4.91 Sig.os026' the idealized formula is Ca3CusSig026, and the structural formula Ca6Cul0{1B, 1~W4Si180d. The mineral is monoclinic, space group C2/c with a=10.160(1), h=1O.001(1), c=19.973(2)A, f)=91.56(1)'" v= 2028.7 A3 and Z = 4. The strongest lines in the X-ray powder diffraction pattern are [d(A),!, hkfj 7.13(60) (110), 6.70(70) (111,111),3.58(40) (220), 3.12(90) (131, 131),3.00(100) (116, 312), 2.45(60) (226), 2.41(70) (226), 1.78(50) (440). Liebauite is biaxial positive with rx= 1.722, /3= 1.723, and y = 1.734 (Ie= 589 nm). Determination and refinement of the crystal struc- ture led to a conventional R value of 0.046 for 818 observed reflections Present address: Universitiit Bremen, Fachbereich Geowissenschaflen, Postfach * 330440, D-2800 Bremcn 33, Fedcral Republic of Germany.
    [Show full text]
  • Boralsilite, Al16b6si2o37, and “Boron-Mullite:” Compositional Variations and Associated Phases in Experiment and Nature
    American Mineralogist, Volume 93, pages 283–299, 2008 Boralsilite, Al16B6Si2O37, and “boron-mullite:” Compositional variations and associated phases in experiment and nature EDWARD S. GR E W ,1,* HE RIB E RT A. GRA E T S C H ,2 BIRGIT PÖT E R,2 MARTIN G. YAT es ,1 IAN BUICK ,3 HE INZ -JÜR ge N BE RN H ARDT ,4 WE RN E R SC H R eye R,2,† GÜNT E R WE RDIN G ,2 CH RI S TO phe R J. CAR S ON ,3 AND GE OFFR ey L. CL ARK E 6 1Department of Earth Sciences, University of Maine, 5790 Bryand Research Center, Orono, Maine 04469-5790, U.S.A. 2Institut für Geologie, Mineralogie und Geophysik, Ruhr-Universität Bochum, D-44780 Bochum, Germany 3Research School of Earth Sciences, Australian National University, Canberra, ACT 0200, Australia 4Zentrale Elektronen-Mikrosonde, Institut für Geologie, Mineralogie und Geophysik, Ruhr-Universität Bochum, D-44801 Bochum, Germany 6School of Geosciences, University of Sydney, NSW 2006, Australia AB S TRACT Boralsilite, the only natural anhydrous ternary B2O3-Al2O3-SiO2 (BAS) phase, has been synthesized from BASH gels with Al/Si ratios of 8:1 and 4:1 but variable B2O3 and H2O contents at 700–800 °C, 1–4 kbar, close to the conditions estimated for natural boralsilite (600–700 °C, 3–4 kbar). Rietveld refinement gives monoclinic symmetry, C2/m, a = 14.797(1), b = 5.5800(3), c = 15.095(2) Å, β = 91.750(4)°, and V = 1245.8(2) Å3. Boron replaces 14% of the Si at the Si site, and Si or Al replaces ca.
    [Show full text]