Study on the Separation of Feldspar from Quarty by Flotation

On activotion of feldspar with hydrofluoric acid

Abstract

Mechanisms of the separation of feldspar from quartz by flotation, using cationic collectors (long chain amine) in acid circuit with hydrofluoric acid have been discussed.
In the acid solution, the adsorption amount of dodecyl ammonium acetate (DAA) on feldspar which had previously been treated with hydrofluoric acid was larger than that on the untreated one or on quartz. The variation in zeta-potential obtained for the acid-treated and untreated feldspar showed so small differences in shapes and in characteristics that little effect of the electrostatic adsorption could be expected to explain the difference in adsorption amount between the acid-treated and untreated feldspar.
Considering the action of feldspar with hydrofluoric. acid and the results of observation by infra-red spectroscope and X-ray diffraction, it was assumed that sodium or potassium fluosilicate was formed on the surface of the mineral and it reacted with amine to give a hydrophobic character to the mineral. Adsorption of DAA to sodium or potassium fluosilicate was so strong that the adsorbed products could not be removed from the surface by washing.
Conceivable conclusions drawn from the studies were that hydrofluoric acid acted as activation agents for feldspar and the acid reacted with quartz and feldspar to form fluosilicic acid. Then the acid was led to potassium or sodium salt by the reaction between the acid and potassium or sodium ion. Amines reacted with insoluble fluosilicate on the surface and made feldspar floatable.