Drop size distribution in a mixer–settler reactor for the gold chloride/DBC system

Abstract

An experimental investigation was carried out in order to analyze the drop size distributions of liquid–liquid dispersion in a horizontal mixer–settler. Two aqueous chemical systems were studied: synthetic gold solution and gold solution prepared from the leaching of copper anode slimes. The dependency of the drop size distributions on impeller speed, 335–600rpm, and phase fraction, 0.167–0.54, were studied for gold chloride–DBC system. The Sauter mean diameter, D32, was correlated for both systems in the frame of classical Hinze–Kolmogorov theory. The results showed that, for each volume fraction in the studied range, D32 is decreasing as a power function of Weber number with an exponent equal to −0.73 and −0.65 for leach and synthetic solution, respectively. This corroborates that the mentioned theory may not be the most adequate to correlate drop size diameters, particularly when reaction occurs in the system. Also such a variation of the exponent may be interpreted as a different combination of the continuous phase. However, for both systems studied, correlation to show the effect of reaction on D32 has been represented. By comparing the results, the prediction of mean drop size diameter in the leach solution is possible by using synthetic solution data with AARD <10%.