| Improvement of the rheological properties, including the yield stress, of the needles of bleached kraft pulp (NBKP) suspension was studied through adding CMC. Results showed that the yield stress increased rapidly with the pulp suspension concentration increasing under steady-state shear conditions, followed an exponent equation, and adding CMC did not affect the relationship. For a given concentration of the pulp suspension, its yield stress would increase firstly and, then, reduce with the increase of CMC dosage, and when adding 1.5% CMC (on oven dry pulp), the yield stress reduced most significantly. With the pulp suspension concentration increasing, the impact of adding CMC on the yield stress was more and more obvious, and when 1.5% of CMC was added into the pulp of 4% concentration, the yield stress reduced the most, reaching 16.2%, which could significantly reduce the energy consumption of the pulp agitation up to about 40.6%. Adding CMC might also reduce the energy dissipation factor at the onset of pulp suspension fluidization, which made it easier to be transported. |
