Abstract: Colloidal Offretite, a process for its manufacture, and zeolite manufacture using it.

Abstract: Zeolite crystals having an offretite structure have smaller crystals and/or can be produced using a synthesis mixture of lower alkalinity than could otherwise be used, if a divalent metal cation, such as magnesium, barium or cobalt is included in the synthesis mixture.

Abstract: The invention concerns a process for the synthesis of zeolites based on element(s) T and mesoporous solids based on element(s) T, T being silicon and/or aluminium, comprising the following sequence of steps:i) synthesizing a reaction medium which is a homogeneous source of element(s) T containing:a) at least one source of element(s) T selected from the group formed by aqueous basic solutions of silica or silica and alumina and alcoholic solutions of alkyl tetraorthosilicate and trialkoxyaluminium;b) optionally, at least one structuring agent;c) optionally, seeds of the desired crystalline phase;ii) heating the reaction medium to a temperature in the range 20.degree. C. to 220.degree. C. for a period in the range several minutes and several days;iii) injecting at least one chemical agent at a controlled rate to generate polycondensable species in said medium.

Abstract: Silica-bound extruded zeolites may be converted into binder-free zeolite aggregates by aging the zeolite in an aqueous ionic solution which contains hydroxy ions such that the initial molar ratio of OH.sup.- :SiO.sub.2 is up to 1.2 and which causes the silica binder to be converted substantially to zeolite of the type initially bound. Such extrudates have excellent mechanical strength and show advantageous properties such as adsorption comparable with non-extruded zeolite powder.

Abstract: Process for the synthesis of a silica-enriched crystalline aluminosilicate having the offretite structure from a nucleation gel A containing sources of silicon, aluminium, alkali metal ions, an organic structuring agent and water and a growth gel B containing sources of silicon, aluminium, alkali metal ions and water. The crystals formed are calcined, the ions are replaced by protons and the crystals are subjected to a hydrothermal treatment followed by a treatment with a strong mineral acid. The aluminosilicate formed has a good selectivity in acid catalysis reactions and is characterized by its good stability.

Abstract: Silica-bound extruded zeolites may be converted into binder-free zeolite aggregates by aging the zeolite in an aqueous ionic solution which contains hydroxy ions such that the initial molar ratio of OH-:SiO.sub.2 is up to 1.2 and which causes the silica binder to be converted substantially to zeolite of the type initially bound. Such extrudates have excellent mechanical strength and show advantageous properties such as adsorption comparable with non-extruded zeolite powder.