Thermodynamic Study on the Flotation Behavior Mechanism of Apatite with Fatty Acid as Collector

摘要

Flotation behavior of apatite was investigated by micro-flotation with five kinds of fatty acid as collectors; the mechanism was studied by thermodynamic calculation. In the thermodynamic discussion, the Gibbs energy (ΔG) of reactions, which is between the collectors and Ca~(2+) ions dissolved by apatite in pulp, were computed with pH as a function. A comparison of the calculated results with the flotation behavior of apatite shows that the thermodynamic results agree well with the experimental data. This finding indicates an identical characteristic between the two reactions with a variation in pH, in which one is between the collectors and Ca~(2+) ions dissolved by apatite in the pulp, and the other is between collectors and Ca~(2+) ions on apatite. Therefore, from the thermodynamic results, the mechanism for the flotation behavior of apatite could be deduced. The decrease in recovery is due to the decrease in effective constituent of collector (A~-) with the falling pH. Once the concentration of A- ions is lower than a certain value, the reactions of the collectors with mineral are terminated and thus result in the depression of apatite in an acidic environment.