Process for the synthesis of a crystalline aluminosilicate enriched in silica, having the structure of mazzite, the aluminosilicate obtained and its use as catalyst for the conversion of hycrocarbons

In a process for preparation of a crystalline aluminosilicate enriched in silica, which has the structure of mazzite, comprising

• (a) preparing a crystallization gel containing a source of tetravalent silicon, of trivalent aluminum and of alkali metal ion, an organic structuring agent and water;
• (b) heating the gel to obtain crystallization and isolating, washing and drying the crystals;
• (c) heat treating the crystals to a heat treatment under a wet atmosphere;
• and
• (d) digesting the crystals with an inorganic acid;
• the improvement which comprises:
• the source of trivalent aluminum consists of crystals of zeolite Y in the form of spheres or botryoids.