PROCESS FOR PREPARING UNIFORM MFI-TYPE ZEOLITE CRYSTALS

摘要

MFI zeolite crystals of uniform and controllable size may be produced by mixing: (i) a source of particulate silica in which silica particles present have an average diameter of 1 mu m or less; (ii) seeds of an MFI zeolite having an average diameter of 100 nm or less in the form of a colloidal suspension; (iii) an organic structure directing agent; and (iv) a source of fluorine or an alkali metal; to form an aqueous synthesis mixture, the seeds being present in an amount of 0.05 to 1700 ppm by weight of the synthesis mixture, and the synthesis mixture having an alkalinity in terms of OH<->/SiO2 molar ratio of less than 0.1, and allowing the synthesis mixture to crystallise.