Eka Nobel Ab

Eka Chemical Ab

Magnus Linsten

Jiri J Basta

Ann-Sofie Hallstrom

Lillemor K Holtinger

Roland Pudas

Lennart Andersson

Roy Hammer-Olsen

Wenche Elisabeth Hermansson

Bjorn Svedin

Ingrid Velander

A process for delignification and bleaching of chemically digested lignocellulose-containing pulp. In a first embodiment, the pulp is acid treated at a pH of between about 1 and about 6, whereupon a water-soluble compound containing an alkaline earth metal is added at a pH of between about 1 and about 7 before the pulp is treated with a chlorine-free bleaching agent. In a second embodiment, the acid and alkaline earth metal treatments are carried out in a single step. The chlorine-free bleaching agent includes peroxide compounds, ozone, oxygen and sodium dithionite in an optional sequence or mixture. After the treatment according to the invention, the pulp may be finally bleached to the desired brightness, suitably with a chlorine-free bleaching agent, such as ozone, to completely avoid formation and discharge of AOX.

Process for acid bleaching of lignocellulose-containing pulp with a magnesium compound

A process for the delignification and bleaching lignocellulosic-containing pulp, in which the pulp is delignified with an organic peracid or salts thereof, treated with a complexing agent, washed and subsequently bleached with a chlorine-free peroxide containing bleaching.

Process for delignification of lignocellulose-containing pulp with an

A substantial and increasing problem with the pulping chemical recovery system, is the presence of chloride and potassium in the spent liquor entering the recovery boiler. Chloride and potassium increase the stickiness of carryover deposits and dust particles to the recovery boiler tubes, which accelerate fouling and plugging in the upper part of the recovery boiler. The present invention relates to a process by which the content of potassium ions in a recovery system for pulping chemicals can be reduced. The process comprises bringing spent liquor to a recovery boiler, burning said spent liquor, collecting precipitator dust formed, forming a solution by dissolving the precipitator dust in a liquid, where the solution of precipitator dust is subjected to a treatment with an inorganic ion exchange material in order to remove at least a part of the potassium therein.

Recovery process in a pulp mill

Process for treating oxygen delignified pulp using an organic peracid or

Growing community of inventors

Kungalv, Sweden

Magnus Linsten