| Three major areas are the focus of this thesis: (1) toner fractionation and the concept of hydrodynamic volume as it pertains to hairy toner particles; (2) flotation of untreated (clean and hairy) and enzyme cleaned (100% clean) toner particles; and (3) visual observations of bubble/toner interactions, and the influence of particle size on degree of attachment and mode of attachment (edge vs. flat).; A visual microscopic examination technique was developed to classify toner particles by size and degree of hairiness. In addition, a Bauer McNett classifier was used to fractionate hairy and enzyme cleaned toner particles. It is shown that the Bauer McNett screens classified particles based on their overall volumes, toner fragment plus any remaining attached fibers.; Flotation results of pulp slurry containing hairy and cleaned toner particles are shown for unfractionated feed and Bauer McNett fractions. A first order kinetic model is used to fit the experimental data and rate constants are calculated. The correlation established between rate constants and hairiness further highlights the negative impact of hairy particles on the flotation efficiency. In addition, it is shown that clean toner particles float independent of particle size within the size range of this study.; To further study toner/bubble interactions and attachment, a new experimental apparatus was designed and constructed. The influence of particle size and flow rate on attachment efficiency has been measured in this apparatus and is discussed. In addition, a correlation between particle size, flow conditions, and overall attachment is obtained. As the flow rate and particle size increase, overall attachment efficiency decreases and, in addition, edge attachment is preferred. An aging effect is also discussed where a decrease in overall attachment efficiency and an increase in edge attachment are observed. |
