Abstract
Previous studies have shown that Pb-BHA complexes (lead complexes of benzohydroxamic acid) have better collecting ability and can be used in flotation experiments with BHA acting as a collector and lead ions acting as activators. However, the structures of Pb-BHA complexes adsorbed on a mineral surface remain unclear. In this work, the adsorption behavior of Pb-BHA complexes on the scheelite surface was studied by flotation experiments and adsorption capacity measurements, and the structures of the adsorbed Pb-BHA complexes were determined using X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (TOF-SIMS). The adsorption capacity results showed that more BHA was adsorbed on the scheelite surface in Pb-BHA flotation, and the XPS and TOF-SIMS analysis showed that the species of Pb-BHA complexes adsorbed on the scheelite surface were similar in activation flotation and Pb-BHA flotation. Therefore, the different contents of the complexes on the scheelite surface were responsible for the flotation behavior. XPS and TOF-SIMS showed that BHA combined with lead ions to form complexes with different structures, such as five- and four-membered ring structures. Structure fragment inference based on the measurements indicated that lead ions formed monomer complexes with two BHAs, and that lead hydroxide polymers with a certain degree of polymerization bonded with oxygen atoms in the complexes. The Pb-BHA complexes combine with oxygen atoms on the scheelite surface to form an adsorbate, rendering the surface hydrophobic.
Highlights
Flotation is a widely used process for material separation, based on differences in the surface hydrophobicity and hydrophilicity of minerals
The adsorption behavior of Pb-BHA complexes on the scheelite surface was studied by flotation experiments and adsorption capacity measurements, and their structures were examined using X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (TOFSIMS), providing an in-depth understanding of the adsorption mechanism of Pb-BHA complexes on a mineral surface
The powdered Pb-BHA complexes precipitates used for XPS, X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Thermogravimetric analysis (TGA) measurements were prepared in solution and dried in a vacuum oven at 40◦C, which the molar ratio of Pb/BHA in complexes were 1:1
Summary
Flotation is a widely used process for material separation, based on differences in the surface hydrophobicity and hydrophilicity of minerals. He et al (2018a,b) characterized the structure of Pb-BHA complexes in aqueous solutions through theoretical calculations and quantum chemical simulations; the results showed that the Pb-BHA complexes existed mainly in the form of Pb-(BHA)n=1,2 at various solution pH values, and first-principles calculations indicated that Pb(BHA)+ is the most stable structure Both studies concluded that the Pb-BHA complexes in the flotation did not consist of a single structure and proposed that PbBHA complexes with multiple structures acted simultaneously on the mineral surface. These studies only analyzed the structure of Pb-BHA complexes in theory by using approaches such as solution chemistry, theoretical calculations, and simulations Such studies are very helpful in understanding the structure of complexes, experimental research was lacking, which is necessary to investigate the true structure of Pb-BHA complexes adsorbed on mineral surfaces. The adsorption behavior of Pb-BHA complexes on the scheelite surface was studied by flotation experiments and adsorption capacity measurements, and their structures were examined using X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (TOFSIMS), providing an in-depth understanding of the adsorption mechanism of Pb-BHA complexes on a mineral surface
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
