SEPARATION PROCESSES OF METALS CONTAINED IN HYPER ACID MEDIUMS BY WAY OF IONIC FLOTATION

1. Process for the separation of metals contained in low concentrations in an inorganic hyperacid medium, by ionic flotation by means of an ionic surface-active agent which plays the role of collector and which is taken particularly from the group of sulfhydrides and organo-phosphorus compounds, and selected from among those which possess at least one polar portion which confers on them a chelating character and at least one hydrocarbon chain of length greater than C6 which confers on them a hydrophobic character, and which are stable in hyperacid media, the surface-active agent being added in an amount such that the ratio vphi = Concentration of surface-active agent/ Concentration of metal >=3.5 and is preferably comprised between 3.5 and 8, to form a coprecipitate or a metal ion-surface-active agent complex, said process comprising in addition the formation of a foam in the hyperacid medium containing said coprecipitate or complex, by the introduction of a gas on the finally dispersed bubbles of which the coprecipitate or complex is absorbed which is recovered in the foam at the surface of the hyperacid medium.