| abstract |
The present invention relates to an acid-stabilized calcium carbonate slurry having anpH of less than 7, preferably between about 6 and about 7, containing water, calciumncarbonate, preferably precipitated calcium carbonate, and an acid-stabilizer of a waternsoluble calcium salt, a weak acid, a chelating agent, a weak acid capable of chelatingncalcium ion, or a mixture thereof. The acid-stabilizer is present in an amountnsufficient to provide an aqueous calcium carbonate slurry having an increased calciumnion concentration and an acidic pH. In a typical acid-stabilized calcium carbonatenslurry of the invention, the acid-stabilizer is present in an amount sufficient to providena calcium ion concentration of about 1 millimolar to about 5 molar, preferably fromnabout 1 to about 120 millimolar. The invention also relates to a method of making thenacid-stabilized calcium carbonate slurry of the invention, to a method of forming anfilled paper, that includes the step of adding the acid-stabilized calcium carbonatenslurry of the invention to a papermaking pulp in a process for making acid paper, andnto a filled paper produced according to the method of the invention |