Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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Author: search.filters.author.Akkurt, SedatSubject: search.filters.subject.Refractories

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  • Article
    Citation - WoS: 61
    Citation - Scopus: 74
    Production of Anorthite Refractory Insulating Firebrick From Mixtures of Clay and Recycled Paper Waste With Sawdust Addition
    (Elsevier Ltd., 2012) Sütçü, Mücahit; Akkurt, Sedat; Bayram, Alican; Uluca, Uluç
    Production of porous anorthite refractory insulating firebricks from mixtures of two different clays (K244 clay and fireclay), recycled paper processing waste and sawdust addition are investigated. Suitability of alkali-containing-clay, low-alkali fireclay, pore-making paper waste and sawdust in the products was evaluated. Prepared slurry mixtures were shaped, dried and fired. Highly porous anorthite ceramics from the mixtures with up to 30% sawdust addition were successfully produced. Physical properties such as bulk density, apparent porosity, percent linear change were investigated as well as the mechanical strengths and thermal conductivity values of the samples. Thermal conductivities of the samples produced from fireclay and recycled paper waste decreased from 0.25 W/mK (1.12 g/cm 3) to 0.13 W/mK (0.64 g/cm 3) with decreasing density. Samples were stable at high temperatures up to 1100 °C, and their cold strength was sufficiently high. The porous anorthite ceramics produced in this study can be used for insulation in high temperature applications. © 2011 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
  • Article
    Citation - WoS: 81
    Citation - Scopus: 97
    Utilization of Recycled Paper Processing Residues and Clay of Different Sources for the Production of Porous Anorthite Ceramics
    (Elsevier Ltd., 2010) Sütçü, Mücahit; Akkurt, Sedat
    Production of porous anorthite ceramics from mixtures of paper processing residues and three different clays are investigated. Suitability of three different clays such as enriched clay, commercial clay and fireclay for manufacturing of anorthite based lightweight refractory bricks was studied. Porous character to the ceramic was provided by addition of paper processing residues (PPR). Samples with 30-40wt% PPR fired at 1200-1400°C contained anorthite (CaO·Al2O3·2SiO2) as major phase and some minor secondary phases such as mullite (3Al2O3·2SiO2) or gehlenite (2CaO·Al2O3·SiO2), depending on the calcite to clay ratio. Anorthite formation for all clay types was quite successful in samples with 30-40wt% of paper residues fired at 1300°C. A higher firing temperature of 1400°C was needed for the fireclay added samples to produce a well sintered product with large pores. Gehlenite phase occurred mostly at lower temperatures and in samples containing higher amount of calcium (50wt% PPR). Compressive strength of compacted and fired pellets consisting of mainly anorthite ranged from 8 to 43MPa. © 2010 Elsevier Ltd.
  • Article
    Citation - WoS: 8
    Citation - Scopus: 12
    A Microstructural Study of Surface Hydration on a Magnesia Refractory
    (Elsevier Ltd., 2010) Sütçü, Mücahit; Akkurt, Sedat; Okur, Salih
    Hydration of the surface of a periclase refractory was studied in a controlled humidity atmosphere (92% relative humidity) at 26 °C for up to 92 h. The effect of humidity on the specimens was examined using a scanning probe microscope (SPM) and a scanning electron microscope (SEM), which showed that the degree of hydration was noticeably less in the intergranular bond phase compared to the periclase crystallites. The SPM study indicated significant growth of hydrates on the refractory grain surface. Growth rate of the hydrate layer was least on (0 0 1) orientation, higher for the (1 0 3) orientation, and highest for the (1 0 1) oriented grain. The rate of loss of refractory phases by hydration on a (1 0 1) oriented grain was 4.53 nm/h. This material loss may be insignificant for a bulk brick, but is a serious threat for a magnesia castable consisting of fine magnesia powder due to large surface area exposed to humidity or water itself. © 2010 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
  • Article
    Citation - WoS: 15
    Citation - Scopus: 17
    Influence of Crystallographic Orientation on Hydration of Mgo Single Crystals
    (Elsevier Ltd., 2009) Sütçü, Mücahit; Akkurt, Sedat; Okur, Salih
    This study has been performed in order to find out the influence of crystallographic orientation on hydration of MgO single crystal substrates with (1 0 0)-, (1 1 0)-, and (1 1 1)-orientations. The samples were left in a hydration chamber with an 88% relative humidity for 18 h at room temperature. The effect of humidity on the samples was examined by scanning probe microscope (SPM) and scanning electron microscope (SEM) which showed that the degree of hydration was noticeably influenced by the crystallographic orientation. It was found that the MgO with (1 1 1)-orientation has the highest tendency to hydrate than the other orientations. Second most affected sample was (1 1 0) crystal. Loss of MgO on the surface by hydration is most severe when the crystal is oriented in (1 1 1) plane with the maximum hydrate layer thickness of 174 nm after 18 h of exposure.