TCF bleaching sequence in kraft pulping of olive tree pruning residues

The aim of the present work was to find a suitable Kraft cooking process for olive tree pruning (OTP), in order to produce pulp of kappa number about 17. The Kraft pulp produced under optimized conditions showed a viscosity of 31.5 mPa·s and good physical, mechanical, and optical properties, which are suitable for paper production. The physical–mechanical and optical properties were measured before and after bleaching. Although the OTP pulp was bleached to 90.9% ISO brightness (kappa < 1), the process demanded a long sequence of stages, OZQPOZQPO. The bleached pulp showed a brightness reversion equal to 1.3%. Furthermore, this bleached pulp did not need a high intensity of beating due to high drainability degree in the unbeaten pulp. So that, OTP is suggested as an interesting raw material for cellulosic pulp production because its properties are comparable to those of other agricultural residues, currently used in the paper industry.

► Chemically characterization and Kraft pulping of olive tree pruning residues.
► TCF bleaching with the following sequence of stages: OZQPOZQPO.
► Obtaining a TCF bleached Kraft pulp with a value of brightness above 90% ISO.
► Analysis of the need to refine the TCF bleached pulp.
► Comparison of physical–mechanical properties of different TCF bleached pulps.