Chemical composition of pitch deposits from an ECF Eucalyptus globulus bleached kraft pulp mill: its relationship with wood extractives and additivesin process streams

The chemical composition of two pitch samples from a Portuguese Eucalyptus globulus ECF DEDED bleached kraft pulp technically integrated with a paper mill, was studied and compared with unbleached and bleached kraft pulp, D-0 and E-1 effluent extractives. The composition of the pitch was dependent o n the location of its deposition in the mill. One pitch sample, collected f rom the bleached pulp thickener, was rich in long chain aliphatic acids res ulting from the accumulation of pulp extractives. The second sample, from t he white water tank of the paper machine, was also composed of long chain a liphatic ketones resulting from decarboxylation of AKD, the sizing agent us ed in the paper mill. Both samples have an important polymeric fraction of an aliphatic nature in their composition.