Type of Document	Dissertation
Author	Flinn, Darrin Heinz
URN	etd-06062008-154507
Title	Modeling bubble-particle interactions in flotation using hydrophobic solid surfaces
Degree	PhD
Department	Mining and Minerals Engineering
Advisory Committee	Advisor Name Title Yoon, Roe-Hoan Committee Chair Davis, Richey M. Committee Member Luttrell, Gerald H. Committee Member Rabionovich, Yokov I. Committee Member Wightman, James P. Committee Member
Keywords	using a geometric mean combining rule. Asymmetric K131 and K232 can be predicted from those of the symmetric inter K132 and infrared transmission spectra showed that OTS AFM images surface forcesAn atomic force microscope (AFM) was
Date of Defense	1996-05-15
Availability	restricted
Abstract An atomic force microscope (AFM) was used to measure surface forces between a glass sphere and a flat fused silica plate under a number of conditions. Hydrophobic surfaces exhibiting contact angles ranging from 0 to 109° were prepared by reacting silica with octadecyltrichlorosilane (OTS). Contact angles, AFM images, and infrared transmission spectra showed that OTS forms clusters on the silica surface. The presence of water in the reaction was shown to greatly influence the formation of these clusters. Forces were measured between surfaces coated with identical (symmetric) and different (asymmetric) amounts of OTS to determine contributions from hydrophobic forces. The results showed that the hydrophobic force parameters of the asymmetric interactions, K132, can be predicted from those of the symmetric interactions, K131 and K232, using a geometric mean combining rule. Asymmetric force measurements were conducted between a hydrophobized glass sphere and a bare silica plate in dodecylamine hydrochloride (DARCl) solutions as a function of pH in an effort to simulate the forces involved in bubble-particle interactions for the quartz-amine flotation system. The appearance of the hydrophobic force in these measurements correlates well with the pH range of maximum flotation recoveries for quartz-amine flotation system.
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