METHOD FOR HANDLING SPENT WASH SOLUTION OF A LIGNIN-RECOVERY PROCESS

USPTO Patent Application US 2017/0211232 A1
Application Date: Jul. 27th, 2017

ABSTRACT

A method for handling spent wash solution produced in the washing of lignin that has been precipitated and then separated from spent alkaline pulping liquor. At least part of the...
Application Number:
15/301,529
International Classification:
D21C 11/00 (20060101); D21C 9/02 (20060101)
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CLAIMS

What is claimed is:

1. A method for handling spent wash solution produced during washing of lignin that has been precipitated and then separated from spent alkaline pulping liquor at a pulp mill, in which method the separated lignin is washed in at least one washing step being conducted under acidic conditions, wherein at...

DESCRIPTION

TECHNICAL FIELD

Lignin may be removed from spent alkaline pulping liquor (black liquor) by first acidifying the liquor and then separating the resulting lignin precipitate. The separated material is usually washed in order to obtain a solid product comprised primarily of lignin and having a reasonably low level of impurity. At least...
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