The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 22, 1999
Filed:
Jul. 08, 1997
Jose M Rodriguez, Eatonton, GA (US);
Steven M Fortier, Milledgeville, GA (US);
ECC International Inc., Roswell, GA (US);
Abstract
A method for producing a high solids slurry of an acid-resistant precipitated calcium carbonate for shipping purposes is disclosed. A low solids of about 18 wt. % to 20 wt. % solids slurry is treated with a chemical additive, such as sodium aluminate, in order to impart acid resistance to the calcium carbonate, and is dewatered to form an intermediate solids slurry of about 44 wt. %. This intermediate solids slurry is then diluted with a fraction of the low solids slurry which was treated with the chemical additive, in order to bring the intermediate slurry to a final high solids slurry of about 35 wt. %. Acid is added to the final product slurry in order to reduce the pH of the final slurry to within a buffering range of about 7.0 to 6.5. The final product slurry of about 35 wt. % comprises an acid-resistant calcium carbonate composition with a pH of about 7.0 which can be shipped for ultimate use when making paper under neutral pH conditions. The final product slurry has a Brookfield viscosity ranging from 200 to 500 centipoise at 100 rpm.