Nucleation, growth and coalescence phenomena of air bubbles on quartz particles in different aqueous solutions

Understanding the generation and behaviour of air bubbles in the presence of different reagents is important in the solid/liquid separation processes used to treat mineral and water and wastewater by flocculation–flotation. The presence of large air bubbles in aerated flocs, which have higher up-rising rates, can lead to the development of higher capacity units. The present work evaluated the generation and behaviour of air bubbles on hydrophilic particles of quartz in water and other aqueous solutions (10 mg L 920SH non-ionic polymer, 30 mg L DF250 surfactant and 50 mg L Flotigan EDA amine). The operating parameters were the air bubble growth time, contact angle, adhesion, attachment and detachment. The main results showed that the air bubbles grew more readily in the presence of non-ionic polymers and after adhesion in non-ionic polymer and water. The formation of large bubbles in aerated flocs in an effort to develop industrial flocculation–flotation operations with higher throughputs units is discussed.