Nordic Pulp & Paper Research Journal | Volume 25: Issue 2 Pre-extraction and PSAQ pulping of Siberian larch Riikka Kämppi 1 , Hanna Hörhammerhanna.email@example.com 1 , Anja Leponiemianja.firstname.lastname@example.org 1 and Adriaan van Heiningenadriaan.email@example.com 2 , 3 1 Department of Forest Products Technology, Aalto University, P.O.Box 16300, FIN- 00076 Aalto,, Espoo, Finland 2 Department of Forest Products Technology, Aalto University, P.O.Box 16300, FIN- 00076 Aalto,, Espoo, Finland 3 Department of Chemical Engineering, University of Maine, 5737 Jenness Hall, Orono,, Maine, USA DOI: https://doi.org/10.3183/npprj-2010-25-02-p243-248 | Published online: 01 Nov 2018 ABSTRACT RECOMMENDATIONS Abstract The aim of this study was to find conditions under which it is possible to produce hemicelluloses-rich extract from Siberian larch in addition to pre-extracted pulp with a yield comparable to normal kraft pulp. The study was conducted in order to determine proof of concept of a process utilizing Siberian larch for production of papermaking pulp and biochemically obtained value-added products, i.e. biofuels or lactic acid. By pre-extraction at 160 ºC for 60 minutes approximately 17% of the wood material could be dissolved. At kappa number 30, the pre-extracted kraft pulp gave 5% lower total yield than a conventional kraft pulp. Addition of 4% polysulfide (PS) and 0.1% anthraquinone (AQ) on wood increased the pre-extracted kraft pulp yield nearly to the same level as that of regular kraft pulp. Pre-extraction at 160 ºC for 60 minutes allowed reduction of EA charge by 3% on wood and Hfactor by 300-450. The viscosity of the pre-extracted PSAQ kraft pulps was higher than that of conventional larch kraft pulps and had a somewhat inferior strength and optical properties. The results indicate that under optimized conditions it is possible to produce preextracted PSAQ larch pulp without significant losses in pulp yield and quality, and in addition generate a new feed stock of carbohydrates for further utilization for value-added products.