The use of nepheline –syenite in a body mix for  Porcelain stoneware tiles

  L.Esposito ,A.Salem- A.Tucci, A.Gualtieri,S.H.Jazayeri

  Abstract

  In the study , the possibility to use nepheline – syenite , as fluxing agent , in abody mix used for porcelain stoneware tile , was determined.

  Starting from the reference mix composition, different amounts ,5.0,10.0 and 15.6 Wt.%, of sodium feldspar were replaced with the same amounts of nepheline –syenite .

  Different sintering cycles were used to understand the role of the nepheline-syenite in the development of the final microstructure.The presence of nepheline- syenite strongly favours the sintering behaviour, by reducing the sintering time necessary to reach the water absorption values, requested by the International Standard.Furthermore , the microstructure results more homogeneous and the mechanical characteristics are increased. The better mechanical performances can also be attributed to the different mineralogical.

  Evaluation of Ru promoted Co/ γ -Al₂O₃ Catalysts in Fischer-Tropsch Synthesis in a CSTR

  S.A. Hosseini, A. Taeb, F. Feyzi

Abstract

  Alumina supported cobalt catalysts promoted by Ru were prepared by co-impregnation method and were investigated in a CSTR. The prepared catalysts have been characterized by XRD, TGA, TPR, H₂-chemisorption and BET measurements and the results are reported. The selected Co loadings for making of catalysts were 15 and 25 wt. %, while the loading of Ru was 1wt. %. Characterization studies showed that the reduction of Ru promoted catalyst with lower content of cobalt (15 wt.%) shows higher reduction than the other sample (25 wt.%), as well as, better dispersion of Co on the support ( γ -Al₂O₃), reduction of particle size of the metal, and pore volume of catalysts. For this work, fractional factorial experimental designs for the evaluation of cobalt catalysts in Fischer-Tropsch synthesis (FTs) were employed. The following reaction parameters were used as independent variable: Temperature, Pressure, GHSV (Gas Hour Space Velocity), rpm and Co wt.%. Using of this method, the best process conditions were achieved. These experiments demostrated that increase of temperature increases CO conversion and C₁ selectivity but reduces C₅₊ selectivity. Increase of Cobalt loading, rpm and GHSV, shifts the reaction toward the production of heavier components. During the reaction, catalysts were deactivated. Deactivation of catalysts during the reaction reduces the rate of secondary reactions, which results in wax production.