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:
Feb. 23, 2016
Filed:
Jun. 22, 2011
Peter Björklund, Umeå, SE;
Martin Wimby, Torslanda, SE;
Henrik Wallmo, Alingsås, SE;
Valmet AB, Sundsvall, SE;
Abstract
The method is for separation of lignin from original black liquor (BL) having the following phases in sequence; a first precipitation phase (PR) for precipitation of lignin by a first acidification of the original black liquor by adding a first acid or mixture of acids (G); followed by a second precipitation phase (PR) for precipitation of lignin by a further acidification of the original black liquor by adding a second acid or mixture of acids (G). The first phase is implemented to lower the pH while avoiding any larger amount of precipitation, i.e. less than 2-5%, while the second phase is implemented in order to obtain the larger part of the precipitation. In total is 40-70% of the total lignin content of the original black liquor precipitated while the residual black liquor after precipitation is still strongly alkaline.