Valmet Ab

Lars-Erik Åkerlund

Per Tomani

Fredrik Öhman

Henrik Wallmo

Martin Wimby

Mattias Svensson

The method is for separation of lignin from original black liquor (BL) and has 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 first storage phase wherein precipitated lignin particles are allowed to increase in size, 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). By retaining the acidified black liquor for at least 25 minutes in the storage phase are the precipitated lignin particles allowed to grow in size and the filterability is improved considerably.

Growing community of inventors

Sollentuna, Sweden

Lars-Erik Åkerlund