Vermiculite composition with improved chemical exfoliation
AssigneeW.R. Grace & Co.-Conn.
InventorsSemyon D. Friedman, Robert W. McKinney, Chia-Chih Ou, Robert M. Spotnitz, Shaohai Wu
Life of this patent
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Abstract
A vermiculite composition composed of particulate vermiculite mineral species having a density of 2.3 g/cm.sup.3 to 2.7 g/cm.sup.3 which has intercalated cations of lithium or organo ammonium and to dispersions obtained therefrom.
Claims21
A vermiculite composition comprising a vermiculite ore concentrate material having at least 85% of at least one vermiculite mineral specie or mixture thereof having a specific density in the range of from 2.3 g/cm.sup.3 to 2.7 g/cm.sup.3 and at least 30 meq/100 gm of the vermiculite mineral specie of intercalated cations selected from the group consisting of lithium, (C.sub.2 -C.sub.6 alkyl) ammonium, allylammonium, or ammonium C.sub.3 -C.sub.6 alkyl carboxylic acid.
A process for preparing a vermiculite dispersion comprising
- a) separating vermiculite mineral material having a specific density within the range of from 2.3 g/cm.sup.3 to 2.7 g/cm.sup.3 from previously formed vermiculite ore concentrate;
- b) treating said separated vermiculite mineral material with a cation exchange salt having a cation selected from the group consisting of lithium, (C.sub.2 -C.sub.6 alkyl) ammonium, allyl ammonium, or ammonium (C.sub.3 -C.sub.6 alkyl) carboxylic acid to cause said cation to be intercalated in the vermiculite mineral material;
- c) immersing the treated vermiculite mineral material in water substantially free of electrolyte;
- d) permitting the immersed vermiculite mineral material to swell in a direction normal to a main cleavage plane thereof to form swollen vermiculite minerals material;
- and
- e) subjecting the resultant swollen vermiculite mineral material while immersed in water to a shearing force to delaminate the vermiculite mineral material;
- and
- f) forming an aqueous substantially uniform suspension of delaminated vermiculite platelets.
A process for preparing a vermiculite dispersion containing
- a) separating vermiculite mineral material having a specific density within the range of from 2.3 g/cm.sup.3 to 2.7 g/cm.sup.3 from previously formed vermiculite ore concentrate;
- b) treating said separated vermiculite mineral material with an aqueous composition of a salt having allyl ammonium cations to cause said cations to be intercalated in the vermiculite in at least 30 meq/100 gm of said vermiculite mineral material;
- c) subjecting the aqueous composition containing the treated vermiculite mineral material to a shearing force to delaminate the vermiculite mineral material;
- and
- d) forming an aqueous, substantially uniform suspension of delaminated vermiculite platelets having an aspect ratio of at least 500:1.
Dependencies are inferred from the claim text.