Study on the Dynamic Viscoelasticity of Bamboo Kraft Black Liquor

The dynamic viscoelasticity of bamboo kraft pulping black liquor under various temperatures (ranging from 50 to 80 degrees C) and solids concentrations (60 to 80 wt.%) was studied. Rotational rheometer analysis data indicated that the viscoelastic motion law with a high solids concentration in black liquor was in accordance with the Kelvin model, and black liquor with a medium concentration conformed to the Maxwell model. As a result, the temperature and solids concentration greatly influenced the dynamic viscoelasticity of bamboo kraft pulping black liquor. For instance, the modulus increased as the solids concentration increased, indicating that the viscous component of black liquor was prominent. For this reason, it was easier to soften the bamboo black liquor, providing a favorable condition for the pure viscosity of black liquor. Steady shear thinning was apparent during the frequency shear process. The dynamic viscosity, storage viscosity, and complex viscosity of the black liquor decreased as the shear frequency increased. The quantitative relationship between dynamic viscosity and angular frequency can be described using the Power Law model.