METHOD OF PREPARING SYNTHETIC A-TYPE ZEOLITE Russian patent published in 2006 - IPC C01B39/18 

FIELD: zeolites.

SUBSTANCE: invention relates to methods of preparing binder-free synthetic A-type zeolite, which could be used in industry to separate hydrocarbon mixture on molecular level, to dry and clean natural and associated gases, and to remove metal and radionuclide cations from water effluents. Natural clayey mineral, kaolin, is mixed with 10-30% of powdered A-type zeolite having microcrystal size 1-2 μm and carboxymethylcellulose taken in amount 2.5-5.0%. The mixture is added with 2% sodium hydroxide solution in amount 10-20% and 1.5% solution of polyvinyl alcohol to form homogeneous plastic mass, which is then granulated. Granules obtained by this way are dried at 50-120°C for 3 h and then thermally activated at 550-630°C, after which cooled and crystallized in alkaline aluminate solution with concentration regarding aluminum oxide 10-30 g/L and regarding sodium hydroxide 100-120 g/L, and ratio of mass of granules to volume of solution equal to 1:(3-5). The latter operation is carried out according to following stepwise temperature regime: 6-8 h at 20-40°C, 6-8 h at 60°C, and 6-8 h at 80°C. Finished zeolite is treated with live steam, washed with softened water, and dried at 120-200°C.

EFFECT: increased degree of crystallinity, dynamic adsorption capacity according to water vapor, and mechanical strength.

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