New Measures for Maximizing Ink Particle Removal in a Flotation Cell, 1997 Recycling Symposium Proceedings

A population balance-type model of the flotation deinking process has been developed using two kinetic constants, which are functions of the microprocesses involved in flotation. These microprocesses are themselves functions of system parameters such as bubble and particle physical properties (e.g., diameter, density), fluid properties (e.g., viscosity, surface tension), and system properties (e.g., turbulent energy density, number of particles). The first kinetic constant, k,, governs the overall probability that a free ink particle will successfully be intercepted by and adhere to an air bubble rising through a flotation cell, thereby accounting for the death of free particles in the unit cell. The second kinetic constant, k2 , addresses the probability that a bubble/ink particle aggregate will become unstable and split to yield a “new” free ink particle, which addresses the birth of free ink particles in the unit cell. Model results have been used to identify three flotation cell performance parameters: (1) flotation efficiency as a function of time, (2) flotation efficiency for a given time period, and (3) the time it takes to reduce the number of free particles by a given amount. Selected predictions of these performance measures will be presented for a wide range of system parameters.