Zeolite granulates with good re:dispersibility and high bulk density

摘要

The following are claimed: (A) zeolite granulates comprising 51-78 (esp. 60-75) wt.% of absolutely dry zeolite and 1-20 (esp. 5-15) wt.% of sodium salts of polymeric or copolymeric carboxylic acids, the granulates have a bulk density of 600-950 g/l., a particle dia. of 300-1000 microns, a surfactant uptake capacity of 30 +/- 5 wt.% and a redispersibility of above 95 wt.%, (B) zeolite granules comprising 51-78 wt.% of absolutely dry zeolite and 1-20 wt.% of sodium citrate. The granules have a bulk density of 600-950 g/l., a particle dia. of 300-1000 microns, a surfactant uptake capacity of 30 +/- 5 wt.%, and a redispersibility of above 85 wt.%, (C) prepn. of zeolite granulates as described in (A) or (B) above, comprising causing zeolite powder or known zeolite granulates to take up drops of a sprayed suspension on their surface, to give a moist agglomerate and drying the moist agglomerate. Pref. the sprayed suspension comprises 15-40% of anhydrous zeolite, 3-40% of (co)polymeric carboxylate or citrate, 0.5-3% of stabilisers and 40-65 wt.% of water, or it comprises 15-40 wt.% of anhydrous zeolite, 3-40% of (co)polymeric carboxylate, 0-25% of soda, 0-20% of citrate, 0-20% of silicate, 0-5% of CMC, 0.5-3% of stabilisers and 40-65 wt.%.