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:
May. 29, 2018
Filed:
Aug. 22, 2013
Upm-kymmene Corporation, Helsinki, FI;
Sanna Valkonen, Lappeenranta, FI;
Kati Oinonen, Imatra, FI;
Juha-Pekka Koitto, Lappeenranta, FI;
Jenni Leppänen, Lappeenranta, FI;
UPM-KYMMENE CORPORATION, Helsinki, FI;
Abstract
The invention relates to a method for recovering low molecular weight lignin from a filtrate, wherein the low molecular weight lignin includes lignin molecules having a molecular weight of 3000 g/mol or lower, wherein the filtrate is obtained from a process where lignin is precipitated from black liquor and the formed precipitate is separated therefrom by filtration resulting in the filtrate including low molecular weight lignin being formed, and wherein the method includes the following steps: a) adjusting the pH of the filtrate to a value of 3-4 for precipitating lignin in the filtrate; b) separating the precipitated lignin from the filtrate; c) reslurrying the separated lignin until the dry solids content of the slurry is 25-40 weight-% and adjusting the pH of the slurry to a value of 2-3; d) washing the slurry; and e) separating the lignin from the slurry.