Journal article
Wall adhesion and constitutive modeling of strong colloidal gels
DR Lester, R Buscall, AD Stickland, PJ Scales
Journal of Rheology | Published : 2014
DOI: 10.1122/1.4891873
Abstract
Wall adhesion effects during batch sedimentation of strongly flocculated colloidal gels are commonly assumed to be negligible. In this study, in-situ measurements of gel rheology and solids volume fraction distribution suggest the contrary, where significant wall adhesion effects are observed in a 110mm diameter settling column. We develop and validate a mathematical model for the equilibrium stress state in the presence of wall adhesion under both viscoplastic and viscoelastic constitutive models. These formulations highlight fundamental issues regarding the constitutive modeling of colloidal gels, specifically the relative utility and validity of viscoplastic and viscoelastic rheological m..
View full abstractGrants
Funding Acknowledgements
This work was conducted as part of AMIRA P266F "Improving Thickener Technology" project, supported by the following companies: Alcoa World Alumina, Alunorte, Anglo American, BASF, Bateman Engineering, BHP Billiton, Cytec Australia Holdings, Exxaro, FL Smidth Minerals, Freeport-McMoran, Hatch, Metso, MMG, Nalco, Outotec, Rio Tinto, Rusal, Shell Energy Canada, Teck Resources, Total E&P Canada, and WesTech. The authors are indebted to Jon Halewood for undertaking the flocculation, rheological, and solid volume fraction profile measurements, Andrew Chryss for design of rheological measurements, and Michel Tanguay for valuable discussions.