Study On Flotation Process And Mechanism Of Refractory Fluorite

In view of the problems of low concentrate grade and low recovery in fluorite flotation process,the flotation process of“one coarse and seven fine”was adopted to obtain high grade fluorite concentrate.At the same time,a new type of modified collector was developed and the action mechanism of unavoidable ions in fluorite flotation process was further explored,so as to provide theoretical reference for the production process of low-grade fluorite flotation.The process mineralogy of refractory fluorite was analyzed by XRD,XRF,SEM,LPSA,chemical detection and other test methods.Using the joint technology of stage grinding and flotation,the best reagent system and technology system to prepare high grade fluorite concentrate was studied,and the results showed that under the condition of roughing reagent regime,the fluorite concentrate with the grade of Ca F₂ 97.2%,recovery rate 82.3%,0.74%of the Si O₂ content was obtained by the final“One coarse and seven fine”closed-circuit process,and reached to FC-97A standard(the secondary fluorite)of the national standard(YBT517-2005).Based on fluorite flotation process,the pure mineral fluorite flotation test,solution chemical calculation,zeta potential,fourier infrared spectroscopy(FT-IR),photoelectron spectroscopy(XPS),surface tensiometer(STM),contact angle analyzer(CAM)and other test methods were adopted and the reaction mechanism of unavoidable ions(NH₄⁺,F^-)in industrial backwater on fluorite flotation with modified sodium oleate was mainly investigated.Intense activation of NH₄⁺in under weak acidic conditions(p H value of 6)was found,and the activation mechanism was that cation adsorption improved surface electropositive,increased the adsorption effect of anionic sodium oleate collector on fluorite surface,making the pulp surface tension and contact angle increased,and the adsorption density of the collector on fluorite surface increased significantly,also cluster adsorption of agents occurs,so the recovery rate of fluorite was improved.However,under the weak alkaline condition(p H value of 8),the hydrolysis of NH₄⁺strongly inhibited the adsorption on fluorite surface,so the adsorption density decreased obviously and the cluster adsorption phenomenon of agents disappeared on fluorite surface,leading to the recovery rate of fluorite decreased significantly.But F^-inhibited fluorite flotation,so the surface potential,surface tension and contact angle of fluorite reduced as well as the adsorption density,resulting in a lower recovery rate of fluorite.FT-IR and XPS test results also showed that the activation of NH⁴⁺enhanced the physisorption and chemisorption on fluorite surface at the same time under weak acid conditions.The characteristic peaks of-CH₃,-CH₂-and C=O were found to be red shifted,and in the high resolution spectra of Ca,F,C and O,the binding energy,photoelectron intensity and peak area increased significantly,moreover the chemical displacement of Ca2P_1/2 and Ca2P_2/3 towards the high binding energy and the peak spacing increased;But under weak alkali conditions,because the hydrolysis of NH⁴⁺weakened the adsorption of-CH₃,-CH₂-and-COO^-on fluorite surface,both the photoelectron intensity and corresponding peak area of Ca-COOR were significantly reduced,-CH₂-peak disappeared in the high resolution spectrum of C,also the C=O peak disappeared in the high resolution spectrum of O.However,the addition of F^-made the characteristic peaks of-CH₂-and-COO^-originally adsorbed on the fluorite surface disappear,and C=O and-COO^-peak in the high resolution spectrum of O disappeared,which inhibited its adsorption on the surface of fluorite.