Binderless zeolite extrudates and method of producing
AssigneeW. R. Grace & Co.
InventorsRichard J. Nozemack, Chang W. Chi, John J. Schwonke
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Abstract
Binderless zeolite sieve extrudates are made by extruding a mixture containing about 40-60% zeolites with the remainder being a metakaolin clay that has mixed with it about 90-120% of the stoichiometric amount of sodium hydroxide to convert the clay to a zeolite. After extrusion the particles are allowed to dry age during which time most of the clay is converted to the zeolite. A further heat treatment in a dilute caustic aqueous solution insures complete crystallization with subsequent washing and calcination to produce an adsorbent product.
Claims9
Process of producing binderless zeolite sieve extrudates containing at least Type A Zeolite from clay and a synthetic zeolite, said extrudates having a higher adsorption capacity, a faster adsorption rate, improved selectivity, and improved attrition resistance, said process comprising
- (a) forming an extrudable mixture of
- (i) a synthetic zeolite,
- (ii) metakaolin clay,
- (iii) sodium hydroxide solution said clay comprising about 40-60% by weight of the total weight of the clay and the zeolite on a dry basis and the amount of sodium hydroxide being in the range of about 90-120% of the stoichiometric amount to convert the clay to a zeolite;
- (b) extruding the mixture of step (a) to form extrudates;
- (c) aging the extrudates;
- (d) treating the extrudates with a dilute solution of sodium hydroxide at an elevated temperature to complete the crystallization of the aged extrudates;
- (e) washing the extrudates;
- and
- (f) recovering the washed extrudates and dry calcining them whereby they can be used as selected adsorbents.
Dependencies are inferred from the claim text.