Papierholz Austria Gmbh

Mondi Ag

Thomas Michael Pichler

Matthaeus Siebenhofer

Marlene Kienberger

Matthäus Siebenhofer

A process for isolating lignin from an alkaline process stream of thickened black liquor which is introduced continuously into a lower region of at least one circulation reactor having two reactor zones in concentric arrangement, liquid level of the alkaline process stream in the interior of the reactor is at a level with an upper end of an inner tubular reactor zone, a CO-containing gas is blown continuously from the bottom into the inner tubular reactor zone of the reactor, wherein the CO-containing gas is absorbed by the alkaline process stream in the inner circulation reactor zone and offgas is drawn off with residual amounts of the COat the top of the reactor, the process is run at 1 atm, and thickened black liquor with a reduced lignin content together with precipitated lignin present are drawn off optionally after settling at the base of the reactor.

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Gabersdorf, Austria

Thomas Michael Pichler