Surface activity and mercury flotation in solutions of n-dodecanoic acid and n-dodecylamine

The flotation and adsorption properties of two ionic collectors (n-dodecylamine andn-dodecanoic acid) are compared on the bases of results of mercury flotation in the model flotation apparatus and electrochemical measurements of the double layer capacity.The flotation recovery and the adsorption parameters (standard free enthalpyG° _A, the interaction coefficient of Frumkin's isotherm, the surface area per molecule) have been determined within the pH range 2.5–12 in solutions of various collector concentrations containing 0.1 N KCl. The maxima of flotation recovery and surface excess have been found at pHs corresponding to pK values for both substances. The influence of the electrolyte on flotation recovery and the gas bubble size distribution dependent upon the pH of the solution is presented forn-dodecanoic acid. The maxima of flotation recovery are involved through the formation of ion-molecule associates (11) as well as an optimum of the bubble size distribution.Publ.-No. 811 from Research Institute of Mineral Processing, Academy of Sciences of the German Democratic-Republic, Freiberg.