Sub-Product

Tall oil, also called liquid rosin or tallol, is a viscous yellow-black odorous liquid obtained as a by-product of the Kraft process of wood pulp manufacture when pulping mainly coniferous trees. The name originated as an anglicization of the Swedish tallolja ('pine oil'). Tall oil is the third largest chemical by-product in a kraft mill after lignin and hemicellulose; the yield of crude tall oil from the process is in the range of 30–50 kg / ton pulp. It may contribute to 1.0–1.5% of the mill's revenue if not used internally. The composition of crude tall oil varies a great deal, depending on the type of wood used. Normally crude tall oil contains rosins, which contains resin acids (mainly abietic acid and its isomers), fatty acids (mainly palmitic acid, oleic acid and linoleic acid) and fatty alcohols, unsaponifiable sterols (5–10%), some sterols, and other alkyl hydrocarbon derivates.