Selective froth flotation of pitch components from spruce TMP process water

• 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 frothflotation was assessed. The experiments were conducted with varying pH, temperature, and concentrations of DoTACand calcium. The concentrations of pitch components, lignans, and dissolved polysaccharides were determinedbefore 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. Resinand fatty acids were removed to a higher degree than neutral pitch substances at all the tested pH levels. Most of thewater-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.

Subject headings

NATURVETENSKAP  -- Kemi -- Fysikalisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Physical Chemistry (hsv//eng)

Keyword

Colloidal pitch

wood resin

mechanical pulp

flotation

anionic trash

Publication and Content Type

ref (subject category)

art (subject category)