tall oil

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.