Relationship between the amount of fine particles and the maximum size of flocs in a weight equivalent suspension of quartz and fluorite

Abstract

Flocculation is largely utilized as an engineering technique in mineral processing practice and the phenomena of fine particles in aqueous suspension can be understood qualitatively through the DLVO theory. However, a clear quantitative theory on the mechanism has not yet been established. Therefore, we studied the flocculation phenomena using quartz and fluorite particles which are negatively and positively charged in aqueous suspension. In this study, experiments were carried out using three quartz samples and three fluorite samples which have different amount of particles smaller than 2.31 μm to clarify the relationship between the amount of fine particles and the maximum size of flocs in aqueous suspension. Quartz particles do not flocculate at all pH values in spite of the variation of the amount of fine particles in the aqueous suspension, while −2.31 μm fluorite particles flocculate into flocs of 13.1–4.63 μm at pH over 10. In addition, an increase in the number of fine particles causes an increase in not the size but the number of flocs. In the case of a weight equivalent mixture of quartz and fluorite particles, hetero-flocculation occurs clearly at pH below 10, and it can be observed that an increase in the number of fine particles influences both the floc size and the number of flocs.