Kvaerner Pulping Ab

Metso Fiber Karlstad Ab

Metso Paper Sweden Ab

Jan Tjernberg

Magnus Ingelman

Anita Markusson

The method is for production of green liquor in association with a causticizing process during recovery of chemicals in manufacture of sulphate pulp. A smelt () of chemicals principally consisting of Na2S and NaCOfrom a soda boiler () is provided. Weak liquor () that contains dissolved NaOH and CaO is provided. A dissolving tank () is provided in which the smelt () from the soda boiler () is dissolved in the weak liquor () it order to form green liquor (). A solution of NaOH is added to the weak liquor (), at a position before the weak liquor () is added to the dissolving tank, in order to increase the concentration of NaOH in the weak liquor () such that a fraction of CaO that is presently dissolved in the weak liquor () precipitates.

Method for the production of green liquor

The pipe system is for receiving and transporting lime sludge from a filter medium in a continuously operating pressurized filter in a causticizing process, where lime sludge is scraped off from the filter medium and falls down into receiving chutes for the lime sludge. Conventional storage tanks for scraped-off lime sludge and their mechanical agitators are thus replaced by a pipe system where the pipe system does not have a mechanical agitator at all but has a flow cross section which maintains a flow rate in the lime sludge so that sedimentation of the lime sludge does not take place from the receiving chute to the feed-out opening of the pipe system.

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Forshaga, Sweden

Jan Tjernberg