Abstract
This paper presents results of tests performed to determine the minimum concentration of a surfactant used at which the probability of occurrence of coalescence of air bubbles during flotation is low. Tests of the coalescence phenomenon were carried out using selected flotation frothing agents such as poly(ethylene glycol) butyl ethers, which are the ingredients of industrial flotation frothers known under the brand name of CORFLOT. Studies were carried out for three successive butyl ethers in the homologous series: ethylene glycol butyl ether (C4E1), diethylene glycol butyl ether (C4E2), triethylene glycol butyl ether (C4E3). Critical coalescence concentration (CCC) surfactant values were determined using the linear regression method. The investigation proved the existence of a clear relationship between the number of ethylene glycol groups in the ether molecule CnH2n+2(OC2O5)nOH and the value of the CCC. The results obtained show a correlation between the CCC values and the molecular weights (MW) of the tested frothers. This article shows the relationship between CCC value and hydrophilic–lipophilic balance (HLB)/MW for the family of polyglycol ethers. Results show the correlation between the critical coalescence concentration and the value of HLB index, being the measure of hydrophilic–lipophilic balance of surfactants (such as flotation frothers), expressed by the weight ratio of hydrophilic portion of the surfactant molecule and its molecular weight. Histograms of air bubbles created a distribution curve similar to the Gauss distribution pattern. The average diameter of air bubbles tends to decrease along with increasing concentration of the tested surfactants. Two characteristic zones that may be distinguished on the graphs show the relationship between Sauter mean diameter and frother concentration. The tests carried out demonstrate that the critical coalescence concentration may be used to characterize the flotation process, as, knowing the CCC values of the frothers used, we are able to control the consumption of foaming agents during mineral processing.
Highlights
Flotation is one of the enrichment processes most commonly used in mineral processing technology
The air bubble diameters obtained for the tested concentrations of the frothers were the critical coalescence concentration (CCC) values (Figure 3)
It is to note that two ranges of frother concentrations are clearly distinguished on each graph used to determine the critical coalescence concentration (CCC) values (Figure 3)
Summary
Flotation is one of the enrichment processes most commonly used in mineral processing technology. One of the most important flotation-influencing factors is the selection of the reagents, of the surfactants, which are the foaming agents called “frothers”. Surfactants are used to disperse gas, produce stable foam, and speed-up the flotation process. These reagents are adsorbed mainly at the interface of water and gas, and their sorption is accompanied by reduction of the surface tension of the aqueous solutions, which, in turn, causes a reduction of the sizes of mechanically produced air bubbles [1,2,3,4,5,6,7,8,9,10,11]. Foam durability depends on the formation of a thin water film around the air bubbles of a structure which prevents water escape from
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
