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. 07, 1998
Filed:
May. 12, 1997
Anatole A Klyosov, Newton, MA (US);
George P Philippidis, Boston, MA (US);
Yiannis A Monovoukas, Waltham, MA (US);
Thermo Fibergen, Inc., Bedford, MA (US);
Abstract
A thermochemical process is provided for the use of pulp and paper sludge as a source of lignin through extraction and recovery. Pulp and paper sludge contains common components of plant materials as well as minerals employed in papermaking. Sludge is mixed in an alkaline solution (NaOH 0.4% to 4% by weight, preferably 0.5% to 2%, and most preferably 1% NaOH by weight). The solution is heated in an autoclave at a temperature of 150.degree.-250.degree. C. (preferably 180.degree.-220.degree. C., and most preferably 200.degree. C.) for a short time, e.g., from about half an hour to an hour. The extracted lignin, present in the alkaline solution, is precipitated by lowering the pH of the solution to a value of 3-5 with the use of, for example, an inorganic or organic acid. The precipitated solid lignin is then recovered and dried.