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US 12,054,886 B2Granted
Method for producing oxidized lignin in kraft pulp mill
AssigneesAndritz Inc., Metsa Fibre Oy, Teknologian tutkimuskeskus VTT Oy
InventorsLauri Pehu-Lehtonen, Pauliina Sjögård, Outi Poukka, Katariina Kemppainen, Anna Kalliola, Tiina Liitiä, Tapio Vehmas
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Abstract
According to an example aspect of the present invention, there is provided a method for producing an oxidised lignin based high performance surface active agent in techno-economically feasible manner within kraft pulp mill without interfering the main process.
Claims15
A method for producing oxidized lignin in a kraft pulp mill comprising at least the steps of:
- isolating unwashed kraft lignin from the kraft pulp mill,
- dissolving the unwashed kraft lignin in oxidized or un-oxidized white liquor to obtain an alkaline lignin solution,
- oxidizing the alkaline lignin solution at alkaline conditions to produce an oxidized lignin with:
- a) O2 gas over pressure, and
- b) added NaOH and/or oxidized white liquor,
- treating the oxidized lignin with membrane filtration and recovering a concentrated lignin product, and
- recovering at least some side products from the membrane filtration as such and recycling the at least some side products and chemicals back to the kraft pulp mill.
4 more elements
Dependencies are inferred from the claim text.