Structural and electronic properties of bastnaesite and implications for surface reactions in flotation

Shiming Cao^1,2，Yijun Cao^2,3，Zilong Ma²，Yinfei Liao²，Xiaolin Zhang⁴

1. School of Resources and Environmental Engineering,Shandong University of Technology2. National Engineering Research Center of Coal Preparation and Purification,China University of Mining and Technology3. Henan Province Industrial Technology Research Institute of Resources and Materials,Zhengzhou University4. State Key Laboratory of Complex Nonferrous Meal Resources Clean Utilization,Kunming University of Science and Technology

摘 要：The structural and electronic properties of bastnaesite were studied by using the first-principles method based on the density functional theory（DFT）.The geometry structure of bastnaesite was first optimized,and then the Mulliken populations,electron density and density of states were calculated and further analyzed in detail.The calculation results reveal that it mainly ruptures along the ionic Ce-O and Ce-F bonds during the cleavage of bastnaesite,leaving≡Ce⁺,≡F^-and≡CO₃^-dangling bonds exposed on the cleavage surface of bastnaesite.Combined with contact angle measurement,surface complexation theory and XPS analysis,the implications of structural and electronic properties on bastnaesite flotation reactions were studied.The hydration of exposed strong ionic bond on cleavage surface results in hydrophilic surface.According to surface complexation theory,the formed surface groups are≡CeOH⁰,≡CO₃ H⁰ and≡FH⁰ groups.The investigated metal ions and flotation reagents complex with surface≡CeOH⁰ groups,while≡CO₃ H⁰ and≡FH⁰ groups are not involved in the complexation.The high activity of Ce atoms facilitates these surface reactions.

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