Metal ion activation in xanthate flotation of quartz

Quartz cannot be floated with potassium amyl xanthate as collector at any pH. Complete flotation is achieved with certain minimal additions of amyl xanthate and Pbtt from pH 5.8 to 8.5 and with amyl xanthate and Znt+ from pH 7.5 to 8.1. The active species of these metal ions responsible for activation are shown to be PbOHt and ZnOHt. No flotation was effected when Cu and Mg were added as activators.