抄録
Soda quinone (AP) and kraft cooking were carried out using softwoods (Douglas fir from North America, domestic red pine) and hardwoods (Eucalyptus from Tasmania, domestic oak). Black Liquor obtained were concentrated to the extent of 70-90% solids concentration in the laboratory in order to compare with the various physical and chemical properties of AP and KP black liquor. This articls deals with the viscosity of high solids AP and KP black liquor measured by “Flow Tester”.
AP black liquor has higher viscosity about 5-10 fold than KP black liquor at the same concentration and temperature. Viscosity of AP and KP black liquor of various softwoods and hardwoods is classified to three groups and viscosity of each groups differs by a factor of 5-10 times.
To investigate the reason for the difference of viscosity of AP and KP black liquors, the influence of four factors was checked.(1) residual alkali (2) ash content as organic/inorganic ratio (3) molecular weight of lignin (4) lignin content in black liquor.
Molecular weight and molecular weight distribution of lignin were not recognized as the cause for the difference of viscosity of AP and KP black liquor. Viscosity of softwoods black liquor is profoudly affected by the difference of residual alkali which is caused by the difference of alkali charge in the AP and KP cooking
