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Porous ceramics supports are, generally, needed for membranes manufacturing. For the development of high-quality supports, the following properties are of major importance: pore size distribution, total porosity ratio, surface quality with the absence of large defects or large pores, good mechanical properties and chemical stability (Gestel et al., 2002). In fact, the top layer is closely related to its support. In addition, the quality of the support is of crucial importance to the integrity of the membrane layers that are applied in the subsequent preparation steps. The required thickness of the membrane is further limited by the smoothness of the support because the membrane material must cover all irregularities of the support to form a continuous, defects free layer (Biesheuvel et al., 2001). The conventional method of preparing ceramic tubes is extrusion. Nevertheless, a problem of extruded ceramic tubes may be encountered such as low surface smoothness (Nijmeijer et al., 1998) and larger average pore sizes. Consequently, an alternative method for such a supports preparation has been proposed (centrifugal casting) [2-9] (Biesheuvel et al., 2001; Nijmeijer et al., 1998; Chen et al., 2005; Steenkamp et al., 2002; Steenkamp et al., 2002; Falamaki & Veysizadeh, 2008; Steenkamp et al., 2001; Kim et al., 2002; Pinggen et al., 2003). Although this method is rather more expensive than extrusion, it is very suitable for manufacturing high-quality tubes (Steenkamp et al., 2002). A centrifuged tube when compared to an extruded tube shows an extremely good roundness, smooth inside surface and a narrow pore size distribution are obtained, which are essential for the quality of membranes that are, afterwards, deposited on this surface (Nijmeijer et al., 1998). This is the main objective of this work which consists of the preparation of adequate and less expensive membrane supports using centrifugal casting process and to investigate the effect of organic content (such as starch) on porosity. For comparison, the raw materials with and without starch addition were prepared. These tubular supports are destined to be used as supports of Micro-Filtration (MF) or Ultra-Filtration (UF) membranes. They permit to provide mechanical strength to a membrane top layer to withstand the stress induced by the pressure difference applied over the entire membrane and must simultaneously have a low resistance to the filtrate flow. The usual starting materials (Al2O3, Mullite, ZrO2, ...) are replaced in this work by a native raw material (Tamazert Kaolin: TK, Djebel Debbag kaolins: DD2 and DD3, dolomite, calcite), in order to reduce the cost of supports fabrication.

Fabrication of Tubular Membrane Supports from Low Price Raw Materials, Using Both Centrifugal Casting and/or Extrusion Methods