The influence of functional groups in frothers on foaming performance and foam stability

Abstract

Flotation is an important method for the separation of fine materials.The type of frothers and the stability of the foam significantly affect flotation performance.In this paper, three foaming agents of alcohols (MIBC), esters (DEP) and ether alcohols (DGBE) are selected to investigate the effect of functional groups in frothers on foaming performance and foam stability.Foamscan was used in the experiment to determine the foaming performance and foam stability of the frothers, and the Tracker rheometer was used to determine surface tension and the viscoelastic modulus of the air-liquid interface.Results show that the foaming rate increases linearly with the decrease of surface tension.It reaches its peak/the maximum when the gas-liquid interface adsorbs the foaming agent to saturation, and when the adsorption of the foaming agent on the gas-liquid interface reaches saturation.The foaming rate of MIBC reaches its peak/the maximum and that of DGBE its trough/the minumum.When the concentration of the frother reaches the critical mass fraction, the foaming ability reaches its peak/the maximum, and the critical mass fractions of MIBC, DEP and DGBE are 1.1 %, 0.4 % and 0.8 %.The size of the bubbles decreases with the decrease of the surface tension of the solution, and the order of the average bubble size from large to small is: DGBE>DEP>MIBC.The ether alcohol frothers have the strongest foam stability, while the alcohol frothers have the worst foam stability.The foam is the most stable.when the mass fractions of MIBC, DEP and DGBE are 0.4 %, 0.5 % and 0.8 %.

Keywords

• functional group
• foaming ability
• foam stability
• surface tension
• viscoelastic modulus