Aggregation and heter-aggregation of ultrafine silica and alumina in flotagent solution

摘要

The aggregation and heter-aggregation of ultrafme particles is of interest from both a fundamental and practical perspective. These behaviors of ultrafme silica and alumina in flotagent solution were examined using particle size analyzer. The aggregation between silica and between alumina particles takes place in surfactant solution. The heter-aggregation between alumina and silica particles was observed in absence of flotagent. The heter-aggregation phenomena may have a pronounced effect on the selective flotation separation of aluminum-silicate minerals from diaspore in reverse flotation of bauxite. The attraction and aggregation behavior between silica and alumina particles in absence and presence of flotagent were examined by using zeta potential, contact angle and AFM measurements. These experimental results have been discussed based on the extended DLVO theory by considering polar interfacial interaction between particle surfaces.