Heterocoagulation of alumina and quartz studied by zeta potential distribution and particle size distribution measurements

Abstract

This paper presents a new approach to characterizing heterocoagulation (i.e. coagulation of mixtures of dissimilar particles) by measuring the zeta potential distribution and the particle size distribution of individual and combined alumina and quartz at pHs 5, 7, and 10. The results show that the heterocoagulation of alumina and quartz would occur at pHs 5 and 7 but not at pH10. For the alumina and quartz particles under study, the aggregate size was mainly between 1.3 and 8.7μm and the quartz would act as the core particle and the alumina as the surrounding particles in the heterocoagulation process. The heterocoagulation and dispersion at different pHs and the aggregate structure at pHs 5 and 7 were verified by the scanning electron microscope analysis. The heterocoagulation and dispersion of alumina and quartz at different pHs can be accounted for by the interparticle force revealed by force analysis in the framework of the Deyaguin-Landau-Verwey-Overbeek theory.