Electrokinetic effects on expression characteristics of clay slurries

Abstract

This paper provides the first report of the particle surface electrokinetic properties effects on expression characteristics in clay slurries. As solution pH decreases or ionic strength increases, the zeta potential becomes less negative. Consequently, the resistance to filtration decreases while the residual moisture in the cake after filtration increases also. The expression data are interpreted by the combined Terzaghi‐Voigt rheological model, from which the model parameters are evaluated. The particle surface electrokinetic properties have only a mild effect on the primary consolidation process, but has, nevertheless, a substantial influence on the secondary consolidation characteristics. Both the easiness of creeping of constituting particles within the sludge cake and the fraction of moisture removal by the secondary consolidation increase when the zeta potential becomes less negative.

Key words:

• expression
• filtration
• creep effect
• clay slurry