PREPARATION OF PLATELIKE ZEOLITE COMPOSITES USING PAPERMAKING TECHNIQUE

Zeolite has been widely applied to practical processes in various industrial fields as a desiccant, an adsorbent, a molecular sieve, an ion exchanger, a catalyst and so on. It has been generally used in the form of beads or pellets. However, these ways of utilization have some fatal disadvantages such as powdering of zeolite itself by rubbing each other and remarkable pressure losses in reaction tower with increasing speed of gas. At first, therefore, the optimum conditions for the preparation of zeolite composite sheets were investigated by the use of paper making technique intending the manufacture of their honeycomb structures. Zeolite sheets, which consisted of 10% pulp, about 30% ceramic fiber and 60% zeolite were easily prepared. The sheets were ignited up at $700^{\circ}C$ to remove pulps, but they were fragile and brittle. For improvement of the zeolite sheet strength, the alumina sol was used as the binders. Although considerably high retention of sol was achieved by the internal addition method with polymer retention aids, the improvement of sheet strength was not satisfactory. In this case, the alumina sol added seemed to be located mainly on the outermost surfaces of sheet because the retention of alumina sol occurred by the filtration effects. On the other hand, soaking treatment of zeolite sheets in the alumina sol increased the sheet strength remarkably. These results indicated that the alumina sol was distributed in the whole sheets and formed the tight network structure between particles. These procedures are expected to prepare useful zeolite products, which have the possibility of new various uses.