The use of alunitic kaolin in the production of ceramic membrane support

Nezahat Ediz,Ilknur Tatar,Ahmet Aydın 한양대학교 세라믹연구소 2015 Journal of Ceramic Processing Research Vol.16 No.1

Although Turkey’s kaolin reserves are substantial, much of the reserves are of alunitic type and the largest deposit of this type is located in the Bal kesir-S nd rg Region. Alunitic kaolin cannot be used in ceramic industry owing to its sulphur content. Since alunite is disseminated within kaolin, it is difficult to remove it from kaolin by using mineral processing methods. In this research, alunite existence within the kaolin was used as an advantage in the production of ceramic membrane support since it allows for the occurrence of desirable homogeneous porosity. For this purpose, 3 different alunitic kaolin samples were taken from the Bal kesir-S nd rg Region and were comminuted. The materials obtained were shaped using dry pressing and slip casting methods to obtain ceramic membrane supports. The supports were sintered at 900 o C-1300 o C for 3 hours. The physical, mechanical and micro-structural properties of the sintered ceramic membrane supports were subsequently determined. The best porosity and strength results were obtained from SB1-1100 and PB1K-1100 coded supports which were made of K1 kaolin (having the highest alunite content).

Development of body formulations using colemanite waste in porcelain tile production

Nezahat Ediz,Arife Yurdakul 한양대학교 세라믹연구소 2009 Journal of Ceramic Processing Research Vol.10 No.6

Porcelain tiles have become one of the most important products of the ceramic industry in the last decade mainly owing to their attractive physical and mechanical properties including high strength, high fracture toughness and density, excellent chemical resistance and low water absorption. The attractiveness of using porcelain has initiated intensive research work for alternative raw materials because of the depletion and the high cost of the usual materials currently used in the ceramic industry. In this research, the aim was to use boron-bearing solid wastes (Ca2B6O11.5H2O) as an alternative fluxing agent to Na-feldspar (NaAlSi3O8) in fast-fired porcelain tile bodies produced under industrial conditions without altering the microstructural, physical and chemical properties required from the final product. For this purpose, the suitability of the colemanite-added porcelain tile bodies to fast-firing conditions was determined using an optical dilatometer. It was then understood that a calcination process was needed in order to effectively use the waste in porcelain tile production. Therefore, the calcination process was applied to the colemanite solid waste before the waste-added bodies were sintered at 1210℃ and 1130℃. The results were compared with those of the standard porcelain tile bodies produced at the same sintering temperatures. After detailed phase analysis (XRD), microstructural examination (SEM-EDX) and physical-mechanical tests, it was found that the standard porcelain tile body produced at 1210℃ (R1) could be obtained at 1130℃ by adding 5% colemanite solid waste (by weight) to the standard tile body to replace Na-feldspar (R7). This result enables production of porcelain tiles at lower temperatures without changing the other operational parameters, only using colemanite waste as a new fluxing agent in the body formulations. Porcelain tiles have become one of the most important products of the ceramic industry in the last decade mainly owing to their attractive physical and mechanical properties including high strength, high fracture toughness and density, excellent chemical resistance and low water absorption. The attractiveness of using porcelain has initiated intensive research work for alternative raw materials because of the depletion and the high cost of the usual materials currently used in the ceramic industry. In this research, the aim was to use boron-bearing solid wastes (Ca2B6O11.5H2O) as an alternative fluxing agent to Na-feldspar (NaAlSi3O8) in fast-fired porcelain tile bodies produced under industrial conditions without altering the microstructural, physical and chemical properties required from the final product. For this purpose, the suitability of the colemanite-added porcelain tile bodies to fast-firing conditions was determined using an optical dilatometer. It was then understood that a calcination process was needed in order to effectively use the waste in porcelain tile production. Therefore, the calcination process was applied to the colemanite solid waste before the waste-added bodies were sintered at 1210℃ and 1130℃. The results were compared with those of the standard porcelain tile bodies produced at the same sintering temperatures. After detailed phase analysis (XRD), microstructural examination (SEM-EDX) and physical-mechanical tests, it was found that the standard porcelain tile body produced at 1210℃ (R1) could be obtained at 1130℃ by adding 5% colemanite solid waste (by weight) to the standard tile body to replace Na-feldspar (R7). This result enables production of porcelain tiles at lower temperatures without changing the other operational parameters, only using colemanite waste as a new fluxing agent in the body formulations.

Characterization of porcelain tile bodies with colemanite waste added as a new sintering agent

Nezahat Ediz,Arife Yurdakulb 한양대학교 세라믹연구소 2009 Journal of Ceramic Processing Research Vol.10 No.4

This research investigated the possible use of high boron oxide (B2O3) bearing solid waste, obtained during the enrichment of colemanite mineral (Ca2B6O11.5H2O), as an alternative sintering agent to Na-feldspar (NaAlSi3O8) in porcelain tile production. The chemical composition, mineralogical properties and behaviour under the heat treatment of solid colemanite waste were characterized in detail by the use of inductive coupled plasma (ICP), X-ray diffraction (XRD) and differential thermal analysis (DTA) / thermo-gravimetric analysis (TG). Physical-mechanical properties of standard and waste-added porcelain tile bodies obtained by sintering at 1210℃ (under factory conditions) such as green strength, dry strength, fired strength and water absorption were determined as a function of waste replacement for Na-feldspar. The sintering behaviour of waste-added porcelain tile bodies under fast firing conditions was also determined by an optical dilatometer and compared with that of standard porcelain tiles. The phases obtained in standard and waste-added porcelain tile bodies after sintering were determined by XRD analysis. The effect of these phases on microstructure and the relationships between physical-mechanical properties and the microstructure were also investigated through a scanning electron microscope (SEM) and energy dispersive X-ray (EDX) spectrometery. After detailed phase studies and microstructural analysis together with the characterization of behaviour under heat treatment, it was discovered that colemanite waste had a high fluxing character and decreased the sintering temperature when used in porcelain tile recipes to replace Na-feldspar. It was also determined that factories using colemanite waste should work at lower sintering temperatures in order to obtain better physical-mechanical properties for porcelain tiles and to reduce energy costs. This research investigated the possible use of high boron oxide (B2O3) bearing solid waste, obtained during the enrichment of colemanite mineral (Ca2B6O11.5H2O), as an alternative sintering agent to Na-feldspar (NaAlSi3O8) in porcelain tile production. The chemical composition, mineralogical properties and behaviour under the heat treatment of solid colemanite waste were characterized in detail by the use of inductive coupled plasma (ICP), X-ray diffraction (XRD) and differential thermal analysis (DTA) / thermo-gravimetric analysis (TG). Physical-mechanical properties of standard and waste-added porcelain tile bodies obtained by sintering at 1210℃ (under factory conditions) such as green strength, dry strength, fired strength and water absorption were determined as a function of waste replacement for Na-feldspar. The sintering behaviour of waste-added porcelain tile bodies under fast firing conditions was also determined by an optical dilatometer and compared with that of standard porcelain tiles. The phases obtained in standard and waste-added porcelain tile bodies after sintering were determined by XRD analysis. The effect of these phases on microstructure and the relationships between physical-mechanical properties and the microstructure were also investigated through a scanning electron microscope (SEM) and energy dispersive X-ray (EDX) spectrometery. After detailed phase studies and microstructural analysis together with the characterization of behaviour under heat treatment, it was discovered that colemanite waste had a high fluxing character and decreased the sintering temperature when used in porcelain tile recipes to replace Na-feldspar. It was also determined that factories using colemanite waste should work at lower sintering temperatures in order to obtain better physical-mechanical properties for porcelain tiles and to reduce energy costs.

Beneficiation of alunitic kaolin within the floor and wall tile angobe compositions

İlknur Tatar,Nezahat Ediz,Ahmet Aydın 한양대학교 세라믹연구소 2015 Journal of Ceramic Processing Research Vol.16 No.1

Most of the kaolin in Bal kesir-S nd rg (Turkey) region cannot be used in ceramic industry because of its high alunite content. The alunite within the composition of kaolin has to be removed in order them to be used in ceramic industry. Therefore, this research aimed at removing alunite from the kaolins of Balikesir-Sindirgi region and investigating its possible use in ceramic industry. For this purpose, mechanical scrubbing-screening, flotation and calcination methods were applied to the kaolins of the region to remove alunite. The material obtained was then used in the floor and wall tile angobe recipes of a ceramic tile factory. The angobes, prepared using the factory’s standard angobe recipes, were applied to the floor and wall tile bodies of the factory and later they were glazed. After the tests, it was understood that F2 angobe prepared by M2 kaolin, beneficiated through the flotation process and F3 angobe prepared by C3 kaolin, beneficiated through calcination could be alternatives for the commercial angobe currently used by the factory in floor tile production. Similarly, it was proven that W2 and W3 angobes prepared by using M2 and C3 kaolins, respectively, could be seen as alternatives for the angobe currently used by the factory in wall tile production.