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The mechanism of fluidization of concentrated calcium carbonate slurries by poly(oxyethylene) diphosphonates |
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| Authors: | M Mosquet Y Chevalier P Le Perchec A Foissy J-P Guicquero |
| Institution: | Laboratoire des Matériaux Organiques à Propriétés Spécifiques LMOPS – CNRS, UPR 9031 B.P. 24, F-69390 Vernaison, France e-mail: yves.chevalier@lmops.cnrs.fr Tel.: +33-4-78022271 Fax: +33-4-78027187, FR Laboratoire d'électrochimie et des Systèmes Microdispersés Université de Franche-Comté UFR des Sciences et Techniques F-25030 Besan?on, France, FR Lafarge Coppée Recherche Laboratoire Central de Recherche, F-38297 Saint-Quentin-Fallavier, France, FR |
| Abstract: | Nonionic poly(oxyethylene) polymers having a diphosphonate group at one chain end strongly adsorb onto CaCO3 particles. The main consequence is a considerable lowering of the viscosity of concentrated slurries. This effect occurs because of the break up and redispersion of aggregates of flocculated CaCO3 particles by the polymer adsorption. The mechanism of colloidal stabilization is steric, the particles becoming uncharged as the polymer adsorbs at their surface. As a consequence, the colloidal suspensions remain stable and fluid at high volume fractions and at high ionic strengths. On the other hand, because of the strong affinity of these polymers for CaCO3 surfaces, the larger part of the polymer is adsorbed until the coverage of the particles reaches completion. The easy to handle polymer-to-solid weight ratio can then be used as a formulation parameter. The depletion flocculation by the nonadsorbed polymer is avoided. Received: 12 March 1999 Accepted in revised form: 2 July 1999 |
| Keywords: | Polymer Adsorption Colloids Stabilization Poly(oxyethylene) diphosphonate |
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