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:
Jul. 06, 1999
Filed:
Jun. 17, 1997
Anatole A Klyosov, Newton, MA (US);
George P Philippidis, Boston, MA (US);
Yiannis A Monovoukas, Walthman, MA (US);
Thermo Fibergen, Inc., Bedford, MA (US);
Abstract
Extraction of minerals from papermaking sludge or sludge-derived ash is accomplished by mixing with a solution of an inorganic or organic acid--generally 0.1% to 35% by weight, preferably 2% to 20%, and most preferably 3% to 8% by weight. In preferred embodiments, the material is carried as an aqueous solution and combined with 2% to 20%, and most preferably 3% to 6%, HCl; 2% to 25%, and most preferably 8%, HNO.sub.3 ; 2% to 30%, and most preferably 8%, acetic acid. Generally, the amount of acid added into the reaction mixture preferably is 0.8 to 2.0 times the stoichiometric calcium carbonate content in the mixture, more preferably 0.8 to 1.2 times the stoichiometric content, and most preferably matched to the stoichiometric content of calcium carbonate in the mixture. The acid-containing mixture is incubated (with agitation, if desired, to shorten the reaction time) to solubilize the desired minerals, following which the liquid phase is isolated, and mineral salts recovered therefrom.