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Selective froth flotation of pitch components from spruce TMP process water
Åbo Akademi Finland / Turku.
Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design. (Water Chemistry)ORCID iD: 0000-0002-0770-2086
Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design. (Water Chemistry)ORCID iD: 0000-0003-3407-7973
Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design. (Organic Chemistry)ORCID iD: 0000-0002-5543-2041
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2012 (English)In: Appita journal, ISSN 1038-6807, Vol. 65, no 4, 337-346 p.Article in journal (Refereed) Published
Abstract [en]

Selective removal of dissolved and colloidal pitch components from an unbleached thermomechanical pulp (TMP)

pressate by addition of a cationic foaming agent, dodecyltrimethylammonium chloride (DoTAC), and subsequent froth

flotation was assessed. The experiments were conducted with varying pH, temperature, and concentrations of DoTAC

and calcium. The concentrations of pitch components, lignans, and dissolved polysaccharides were determined

before and after flotation.

All pitch components were removed more efficiently by flotation at pH 5 and 3.5 than by flotation at pH 7.6. Resin

and fatty acids were removed to a higher degree than neutral pitch substances at all the tested pH levels. Most of the

water-soluble uronic acids and galactoglucomannans stayed in the TMP water after flotation.

Froth flotation with DoTAC was an effective way of selectively removing colloidal and dissolved pitch. Removal of pitch,

especially of resin acids, at an early stage should be beneficial to the overall papermaking process.

Place, publisher, year, edition, pages
2012. Vol. 65, no 4, 337-346 p.
Keyword [en]
Colloidal pitch, wood resin, mechanical pulp, flotation, anionic trash
National Category
Physical Chemistry
URN: urn:nbn:se:miun:diva-17243ISI: 000309898500026OAI: diva2:562791
EU, European Research Council
Available from: 2012-11-02 Created: 2012-10-26 Last updated: 2016-09-29Bibliographically approved
In thesis
1. Selective Separation Of Wood Components In Internal Process Waters Originating From Mechanical Pulping
Open this publication in new window or tab >>Selective Separation Of Wood Components In Internal Process Waters Originating From Mechanical Pulping
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Dissolved and Colloidal substances (DSC) and metals are released from woodduring thermomechanical pulp (TMP) production. These components have atendency to accumulate in process waters, as the water circulation systems inintegrated paper mills are closed. Disturbances such as pitch depositions in thepaper machine (pitch problems), specks in the paper, decreased wet and drystrength, interference with cationic process chemicals, and impaired sheetbrightness and friction properties appear when DSC are present. Transition metalions such as manganese results in higher consumption of bleaching chemicals(hydrogen peroxide) and lowers the optical quality of the final product, andaddition of complexing agents, such as EDTA or DTPA, to prevent this is needed.The never ending trends to decrease water consumption and increase processefficiency in pulp and paper production emphasizes that it is very important bothto know the effects of wood substances on pulping and papermaking and to beable to remove them in an efficient way. From a biorefinery point of view, DSCcomponents can be promising renewable raw materials for biofuels, bio‐basedchemicals and materials.In this thesis, a new approach using induced air flotation (IAF) without a cationicpolyelectrolyte addition for the removal of pitch and metal ions from mechanicalpulp mill process waters is presented. The induced air flotation of different processwaters is facilitated by the addition of a chelating surfactant and different foamingagents. The influence of the pH value, temperature and foaming agentconcentration on the flotation efficiency has been investigated. The investigations

presented show that the disturbing components can be removed from TMP presswater to a high extent. A 90% decrease in turbidity and a 91% removal of lipophilicextractives (i.e. resin and fatty acids, triglycerides, sterols and steryl esters) fromunbleached and bleached TMP process water can be obtained by addition of acationic surfactant as foaming agent during flotation. Lower amount of foamingagent is needed to purify efficiently bleached TMP process water, than unbleached.Additionally, fibres located in TMP press water are not removed with the foamfraction but purified. A retained concentration of hydrophilic extractives (i.e.hemicelluloses and lignans) in the process water indicates that the flotation isselective. Moreover, by introduction of a new recoverable surface activecomplexing agent, a chelating surfactant, manganese ions in the form of chelatescan be successfully removed from the pulp fibres and separated from the processwater in the same flotation process. Furthermore, from the purified unbleachedTMP process water a 90% recovery of dissolved hemicelluloses by anti‐solventprecipitation was obtained.The findings presented above indicate new possibilities for the internal watercleaning stage to decrease DSC emissions to recipient and for recovery of valuableraw materials from purified process water if flotation technology is applied in anintegrated mechanical pulp mill.

Place, publisher, year, edition, pages
Sundsvall: Mid Sweden University, 2014. 178 p.
Mid Sweden University doctoral thesis, ISSN 1652-893X ; 184
flotation, foaming agents, chelating surfactant, TMP process water, pitch control, internal cleaning stage, hemicellulose recovery, anti‐solvents, solvents, precipitation
National Category
Polymer Chemistry
urn:nbn:se:miun:diva-22244 (URN)978-91-87557-45-3 (ISBN)
Public defence
2014-05-28, O102, Holmgatan 10, Sundsvall, 12:33 (English)
Knowledge Foundation, 2180
Available from: 2014-06-27 Created: 2014-06-23 Last updated: 2015-03-13Bibliographically approved

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