Mineral-Content and Particle-Size Effects on the Colloidal Properties of Concentrated Lateritic Suspensions

A. Cerpa1, M.T. Garía-González2, P. Tartaj1, J. Requena1, L. Garcell3 and C.J. Serna1
1 Instituto de Ciencia de Materiales de Madrid, (CSIC), Campus de Cantoblanco, 28049 Madrid, Spain
2 Centro de Ciencias Medioambientales de Madrid, (CSIC), Serrano 115 Dpdo, 28006 Madrid, Spain
3 Facultad de Ingeniera Química, Universidad de Oriente, Ave. Las Américas s/n, Santiago de Cuba, Cuba

Abstract: The rheological behavior of concentrated lateritic suspensions from Cuba is affected by mineral composition and particle size. Electrophoretic mobility and yield stress were considered. The lateritic samples were found to be mostly composed of mixtures of serepentine and goethite in varying proportions. The flow properties of the lateritic suspensions are strongly affected by the mineral composition and particle size. This result was determined by comparison of flow properties of the bulk sample and the colloidal fraction. The electrokinetic curves suggest that heterocoagulation is present in all samples, with a zeta potential minimum at the isoelectric point (IEP), which varies with the serpentine to goethite ratio. A relationship between yield stress (τ0) and the sample volume fraction (φ) and particle size (d) was obtained at the IEP from the expression τ0 = kφ3/d0.5, with the constant k dependent on the sample serpentine to goethite ratio.

Key Words: Concentrated Suspensions • Heterocoagulation • Interfacial Mobility • Lateritic Suspensions • Mineral Content of Suspensions • Rheology • Yield Stress

Clays and Clay Minerals; August 1999 v. 47; no. 4; p. 515-521; DOI: 10.1346/CCMN.1999.0470414
© 1999, The Clay Minerals Society
Clay Minerals Society (www.clays.org)