Analysis Of Zircon Surface Microstructures And Molecular Design Of Targeted Collectors

Flotation is the most important mineral processing technology for fine particle separation.The research and development of highly selective mineral flotation reagents have always been a hot spot in the field of mineral processing.However,the traditional reagent screening and design mainly rely on the"trial and error"method,which mainly focuses on the structure and property of flotation reagent itself,lacks in-depth research on the structure and property of the target mineral surface resulting in the challenge to screen highly-precise“targeted”flotation reagents.Clarifying the reactivity of molecular scale microstructure on the mineral surface and its interaction mechanism with flotation reagent is the key to realizing the targeted screening and design of flotation reagents.In this paper,the density of crystal plane fracture energy（Sc）method and small molecule detection method are proposed to analyze the reactivity of mineral exposed surfaces and target sites,the reaction Gibbs free energy criterion of reagent-metal ion cluster is proposed to screen polar groups,and an efficient selective collector screening and design scheme based on the target reactivity on the mineral surface is established.Two target flotation collectors have been developed,and their action mechanism and interfacial bonding mechanism of the targeted reagent with zircon surface is revealed through quantum chemistry calculations and highly precise experimental approaches.Finally,the obtained flotation reagents have been successfully applied in the flotation of zircon pure minerals and actual ores.The obtained results might support the efficient separation and recovery of micro-fine and complex refractory zircon.The main innovative achievements of the research are as follows1.The Sc method based on bond order weighting is proposed to quickly and accurately analyze the crystal plane fracture difficulty and surface activity of zircon crystals with various chemical bonds,and verify that there is a good correlation between crystal plane fracture energy and surface energy.The results show that the common exposed surface of zircon crystal is（200）surface,and the number of broken bonds at Zr site on the surface is between 1～4.The small molecule detection method further showed that the higher the coordination number of the zirconium site,the lower the reaction activity.The reactivity of zirconium sites is weaker than that of iron sites with common pig iron minerals.2.The Gibbs free energy criterion and selective bonding index（SBI）of the simple reagent-metal cluster models（SRMC）are proposed to accurately screen the targeted flotation reagent.By splicing the screened polar groups and the designed hydrophobic groups,two targeting agents,n-octyl phosphoric acid（n OPA）and octyl hydroxamic acid（OHA）,were obtained.Compared with traditional oleic acid,the results show that the interaction between the two targeted collectors and the zirconium site is stronger than that of oleic acid.Considering the commonly associated minerals and surface pollutants of zircon is the iron-bearing ore,the selectivity of the database for Zr and Fe sites was further explored.SBI results showed that all reagent molecules could not preferentially interact with Zr because the reactivity of the Fe target was greater than Zr.3.In an aqueous solution,n OPA ions are bonded to zirconium sites on the surface by a single bond,and OHA and oleic acid preferentially form a hydrogen bond with the surface.Among them,n OPA has the largest adsorption energy and is the most effective zircon-targeted collector.Electron localization function,the projected density of states,and crystal orbital overlap population analysis show that the chemical bond between the targeted reagent and the zirconium site on the mineral surface is an ionic bond.4.The results of potentiodynamic potential,X-ray photoelectron spectroscopy（XPS）,infrared and Raman spectroscopy and atomic force microscopy（AFM）show that the traditional sodium oleate（Na OL）is adsorbed on the positively charged zircon surface in the form of colloid on the mineral surface,which has a weak effect,poor targeting and easy desorption.OHA can be targeted adsorbed on the surface of zircon,with moderate interaction,moderate targeting and easy desorption.OHA are also prefer to adsorb onto iron sites than on Zr site.n OPA is mainly chemically adsorbed at zirconium sites on the surface of zircon,forming n OPA-（Zr≡）₂,with strong interaction,strong targeting and stable monolayer adsorption.5.The process mineralogy results of 801 mine in Inner Mongolia show that the main valuable minerals in the raw ore are uranium bearing zircon and more iron bearing impurity minerals.Iron impurity minerals will consume a large amount of collector and activate gangue minerals,resulting in insufficient separation efficiency of zirconium concentrate.Using the pre-scrubbing can effectively remove the impurity iron minerals in the pulp,to improve the separation efficiency of the targeted collector.The real ore flotation results show that the Na OL collector has poor collectability and selectivity.OHA will preferentially collect iron-bearing minerals,and its selectivity for iron-bearing minerals is better than that of zircon.n OPA has better collectability and selectivity than traditional collectors.The optimal Zr recovery obtained by n OPA was 77.5%.Uranium is mainly enriched with concentrate,and the recovery is 67.1%.77 figures,38 tables,and 202 references...