INTERACTION OF FINELY GROUND GALENA AND POTASSIUM AMYLXANTHATE IN FLOTATION .1. INFLUENCE OF ALKALINE GRINDING

Diffuse reflectance Fourier transform infrared spectroscopy, Hallimond tube flotation cell and microelectrophoresis have been utilized to investigate the reactions involved in the adsorption-abstraction of K-amylxanthate on finely ground galena. The mineral was ground in a laboratory stainless steel rod mill in basic conditions (pH 11.0 and 12.5). pH regulators were NaOH and CaO. A two-stage adsorption process was discovered for amylxanthate at pH 11.0. During the first stage a mixed layer is formed. For low concentrations or submonolayer capacity it is made of 1:1 monocoordinated lead xanthate and dixanthogen; for surface coverage up to 5.4 it is composed of nonstoichiometric lead xanthate, amyldixanthogen and amylcarbonate disulphide. In the second stage, mainly amyldixanthogen is formed; at high xanthate concentration (1×10-2 mole per dm3) 1:2 coordinated lead xanthate is formed in addition. The second-stage process corresponds to complete flotation and to a sharp decrease in zeta potentials. © 1990.