Study On Enhanced Flotation Separation Of Rare Earth Ore Based On The Regulation Of Surface Dissolved Species Composition

The bastnaesite-type rare earth minerals are salt minerals with high solubility.The large amounts of dissolved species are dissolved during the flotation process,and adsorption,precipitation,migration and transformation reactions occur between the mineral surface,making the mineral interface properties tend to be the same.It is difficult to control and make flotation separation very difficult.This study systematically studied the effect of the dissolved species of three typical gangue(calcite,fluorite and barite)in bastnaesite on the flotation of bastnaesite.The influence mechanism of behavior;the selective adsorption,precipitation,migration and transformation mechanisms of the dissolved species of gangue at the interface are explored;and based on the migration transformation mechanism,the selective flotation separation of bastnaesite was screened out green and efficient depressors,and the selective mechanism of depressors and minerals has been studied.This research has important theoretical reference value for solving the technical problems of flotation separation of bastnaesite,and further improving the strategic guarantee and comprehensive utilization of rare earth resources in China.The results of the study are as follows:(1)In the flotation system using sodium oleate(Na OL)as the collector,the dissolved species of calcite,fluorite and barite significantly inhibit the floatability of bastnaesite under strong acid-base conditions,so that the recovery decreased sharply.In the supernatants of calcite,fluorite and barite gangue minerals near p H=11,the flotation recovery of bastnaesite decreased by about 83%,80% and 40%;in addition,calcite and fluorite the stone supernatant has a strong depressed effect on bastnaesite buoyancy in the p H range of 8-9,while the barite supernatant and a single dissolved ion have almost no depressed effect on the bastnaesite in this range.(2)Through Zeta potential,FTIR,in situ ATR-FTIR,XPS tests,combined with mineral crystal chemical analysis and DFT theoretical simulation calculations,the selectivity of gangue dissolved species on the surface of bastnaesite is further revealed from the molecular and atomic level adsorption,precipitation,migration and transformation mechanisms.The metal cation and anion groups dissolved from the gangue minerals are transformed into hydroxyl species and various metal salts in the solution,which are adsorbed on the bastnaesite surface and hinder the adsorption of the collector.Among them,the dissolved species of calcite have a significant depressed effect on the physical adsorption of oleic acid dimer and the chemical adsorption of oleic acid ions,but the depression of the physical adsorption of oleic acid monomer molecules was relatively weak;fluorite and barite are dissolved.Species have no obvious effect on the physical adsorption of various forms of oleic acid molecules,but they inhibit the chemical adsorption of oleic acid ions significantly.(3)Based on the proven migration and transformation mechanism of the dissolved species of gangue minerals,and the difference in reactivity between depressors and dissolved species,it is mainly aimed at depressing the adsorption of metal hydroxyl compounds and metal salts.Xanthan gum,sodium alginate and sodium lignosulfonate are screened out as the bastnaesite are green depressors with flotation separation effect.And through in situ microcalorimetry and FTIR tests,the selective mechanism of depressors was studied.The results of the study show that the selective chemical adsorption reaction between the free carboxyl groups in the structure of xanthan gum and sodium alginate and the Ca particles on the mineral surface is one of the reasons for its flotation separation effect,and the sodium lignosulfonate mainly physically interacts with the mineral surface.