THE RELATIONSHIP BETWEEN HYDRODYNAMIC VARIABLES AND KINETIC
CONSTANT IN LAB SCALE FLOTATION COLUMN
Ali Vazirizadeh*, Jocelyn Bouchard and René del Villar
LOOP (Laboratoire d’observation et d’optimisation des procédés),
Department of Mining, Metallurgical and Materials Engineering, Université Laval, Canada
Industrial flotation is a continuous and often multistage process, where particles of a given mineral species
(usually the targeted one), present in different sizes, encounter a large amount of gas bubbles (normally air) to produce mineral–bubble aggregates, which are removed from the flotation device (cell or column) as a valuable product (concentrate). The bubble content inside the cell is characterized by the prevailing hydrodynamic conditions (known as gas dispersion variables), which in turn are known to influence the flotation performance. Although most researchers and practitioners agree that the relationship between the hydrodynamic variables and flotation performance exists, the lack of an adequate method for on-line measuring the average bubble diameter has prevented such studies.
The aim of this study is applying appropriate hydrodynamic variables for flotation kinetic modeling (as a key feature of flotation performance) based on a given introduced particle size distribution. In this regard, experiments were conducted in a laboratory flotation column (5.6 cm internal diameter for a total height of
650 cm), and mixtures of quartz (hydrophilic gangue) and talc (naturally hydrophobic mineral), classified in four different size fractions. The correlation between the flotation rate constant and given hydrodynamic variables has been analyzed. Results suggest that the relative importance of hydrodynamic variables for flotation rate modeling depends on the particle size distribution. Finally the suggested hydrodynamic variables for each of the various particle size-classes considered were used to produce single variable models for the flotation rate constant.
KEYWORDS
Flotation, Kinetic constant, Bubble size, Gas hold-up, Bubble surface area, Interfacial area of bubbles
* Corresponding author. Tel.: +1 581 9986866; Fax: +1 418 6565343.
E-mail address: a.vazirizadeh@gmail.com (A. Vazirizadeh).