Surface pacified wollastonite
AssigneeArmstrong World Industries, Inc.
InventorJeffery L. Barrall
Life of this patent
Estimating the term…
Abstract
Wollastonite acid treated and dried to pacify the surface processes more uniformly in subsequent reactions or remains inert when used as a filler. Phosphate cements prepared with the pacified wollastonite or similar calcium silicates exhibit improved strength and scratch resistance.
Claims20
A method for pacifying wollastonite comprising the steps:
- (a) reacting the wollastonite in an aqueous acid medium to convert its surface by reaction with the acid further providing that the acid gives the wollastonite a displaceable anion without altering crystal structure, and
- (b) drying the wollastonite wherein, step (b) terminates the step (a) reaction, to provide a pacified product wherein 2% by weight or less of the total wollastonite is reacted.
An acid pacified wollastonite having 2% by weight or less of the wollastonite reacted with the acid, and having a displaceable anion provided by the acid.
The acid pacified wollastonite of claim 13 having a pH of 9-10 when slurried in water.
A shaped article containing acid pacified wollastonite.
A phosphate ceramic which was prepared from a reaction of phosphoric acid, a metal oxide, and wollastonite, the said wollastonite being an acid pacified wollastonite having a displaceable anion from the acid;
- wherein further, the acid pacified wollastonite which was used for the ceramic had a degree of pacification whereby, a slurry of the wollastonite would give a pH value in the range of 9-10.
Dependencies are inferred from the claim text.