Application of Extended DLVO Theory: Modeling of Flotation and Hydrophobicity of Dodecane

Simple item page
dc.contributor.authorMao, Laiqunen
dc.contributor.committeechairYoon, Roe-Hoanen
dc.contributor.committeememberXu, Zhengheen
dc.contributor.committeememberDavis, Richey M.en
dc.contributor.committeememberAdel, Gregory T.en
dc.contributor.committeememberLuttrell, Gerald H.en
dc.contributor.departmentMining and Minerals Engineeringen
dc.date.accessioned2014-03-14T20:17:15Zen
dc.date.adate1998-11-13en
dc.date.available2014-03-14T20:17:15Zen
dc.date.issued1998-05-23en
dc.date.rdate1999-11-13en
dc.date.sdate1998-10-10en
dc.description.abstractThe extended DLVO theory was used to develop a flotation model by considering both hydrodynamic and surface forces involved in the process. A stream function was used to estimate the kinetic energies for thinning the water films between bubbles and particles, which were compared with the energy barriers, created by surface forces, to determine the probability of adhesion. A general expression for the probability of detachment was derived from similar mechanism for chemical reaction, and the kinetic energy for detachment was estimated with French and Wilson's model. The hydrophobic force parameter (K132) calculated from the rate constants of single bubble flotation tests showed that, K132 for bubble-particle interaction were close to the geometric means of K131 for particle-particle interactions and K232 for bubble-bubble interaction, indicating that the combining rules developed for dispersion forces may be useful for hydrophobic forces. The model was used to predict flotation results as functions of several important parameters such as contact angle, double-layer potentials, particle size, bubble size, etc. The predictions were consistent with experience, and could be explained in view of the various subprocesses considered in the model development. Furthermore, the model suggested optimum conditions for achieving the maximum separation efficiency. The extended DLVO theory was also used to determine the hydrophobic force between two oil/solution interfaces from the equilibrium film thicknesses of dodecylammonium chloride (RNH3Cl) solutions obtained using Thin Film Balance (TFB) technique. The results showed that, the oil droplets were inherently hydrophobic, and the hydrophobic force played an important role in the stability of emulsions. This force decreased with increasing surfactant concentration, and also changed with pH and the addition of electrolyte. The interfacial area occupied by molecules indicated that, the dodecane molecules might present between two surfactant ions at interface, thus the hydrophobicity of oil/solution interface was less sensitive to the addition of the surfactant than that of air/solution interface. Thermodynamic analysis suggested that, there might exist a relationship between the interfacial hydrophobicity and the interfacial tension.en
dc.description.degreePh. D.en
dc.identifier.otheretd-100998-123843en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-100998-123843/en
dc.identifier.urihttp://hdl.handle.net/10919/29232en
dc.publisherVirginia Techen
dc.relation.haspartMAO_DISSERTATION.PDFen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectDodecaneen
dc.subjectFlotation Modelingen
dc.subjectExtended DLVO theoryen
dc.subjectHydrophobic Forceen
dc.titleApplication of Extended DLVO Theory: Modeling of Flotation and Hydrophobicity of Dodecaneen
dc.typeDissertationen
thesis.degree.disciplineMining and Minerals Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en

Files

Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
MAO_DISSERTATION.PDF
Size:
781.72 KB
Format:
Adobe Portable Document Format
Download

Collections

Doctoral Dissertations