Study On Mechanism Of Composite Depressant In Floatation Separation Of Bastnaesite And Fluorite

Flotation is a commonly used beneficiation method for separation of rare earth minerals from gangue minerals.The surface properties and floatability of bastnaesite and its main associated gangue mineral fluorite are similar,so their flotation separation is difficult.The dissolution of minerals causes the inevitable large number of metal ions in pulp,which aggravates the difficulty of flotation separation between the two minerals.At present,single water glass inhibitor is commonly used in rare earth flotation,and the separation effect is not good.Therefore,it is of great guiding significance to study the compound depressant for floatation separation of bastnaesite and fluorite to improve the separation efficiency.In this paper,bastnaesite and fluorite are the main research object,through means of surface characteristics,floatability,solubility,flotation test,zeta potential test and XPS test,the influence of inevitable metal ions on the flotation of bastnaesite and fluorite is studied.And the influence of inevitable metal ions on the flotation of bastnaesite and fluorite is eliminated by composite inhibitors.The activation effect of Ce³⁺in pulp on fluorite flotation and the inhibition effect of Ca²⁺on water glass inhibiting bastnaesite flotation were studied.The results show that Ce³⁺ions can activate fluorite flotation,Ce³⁺ions dissolved from bastnaesite would adsorb on fluorite surface,which makes fluorite surface similar to bastnaesite.The inhibition of water glass on bastnaesite is weak,which reduces the inhibition of water glass on fluorite;Ca²⁺ions can enhance the inhibition of water glass on bastnaesite flotation,Ca²⁺dissolved from fluorite would adsorb on the surface of bastnaesite,which makes the surface of bastnaesite similar to fluorite.The inhibition of water glass on fluorite is stronger,thus enhances the water glass inhibition on bastnaesite.The interaction law of inevitable metal ions in pulp on bastnaesite and fluorite flotation is determined.The effect of water glass-EDTA/citric acid/Oxalic acid composite depressant on the Ca²⁺enhanced inhibition of bastnaesite flotation and the deactivation effect on the flotation of fluorite activated by Ce³⁺ion were studied.The results show that EDTA and citric acid have deinhibition effect on Ca²⁺enhanced inhibition of bastnaesite,and excessive amounts of EDTA and citric acid can inhibit floatation of bastnaesite,while oxalic acid has no deinhibition effect on water glass.The inhibitory capacities of the three composite agents were as follows:EDTA>citric acid>oxalic acid.The effect of water glass-EDTA,water glass-citric acid compound inhibitor ratio on flotation separation of bastnaesite and fluorite artificial mixed ore was studied.The results show that when the compound inhibitor EDTA:WG=1:3,the bastnaesite concentrate grade of 67.4%and recovery of 98.27%was obtained.The separation coefficient of bastnaesite and fluorite reaches 23.04,and the separation effect was the best.The mechanism of Ca²⁺enhanced inhibition of bastnaesite flotation was studied.The results show that the adsorption of Ca²⁺ions on the bastnaesite surface increases the cationic active sites on the surface of bastnaesite,thus increasing the adsorption density of water glass on the surface,further reducing the adsorption capacity of OHA collector,thus inhibiting the flotation of bastnaesite.