Modification mechanism of lead ions and its response to wolframite flotation using salicylhydroxamic acid

The surface modification of wolframite by Pb2+ ions and its influence on the flotation of wolframite using a salicylhydroxamic acid (SHA) collector were investigated through microflotation experiments, contact-angle tests, zeta-potential measurements, atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). The results indicated that the addition of Pb2+ ions increased the SHA adsorption onto wolframite surfaces and contributed to the concomitant increases in the hydrophobicity and floatability of wolframite. Results of zeta-potential and XPS analyses confirmed that Pb2+ modification occurred via ion exchange, dehydration reaction, and precipitation reaction, generating Pb-containing complexes on wolframite surfaces. As expected, the Pb2+-modified wolframite exhibited increased interaction with SHA. The results of zeta-potential, FT-IR and XPS analyses indicated that SHA species reacted with Pb-containing complexes adsorbed on the wolframite surfaces, forming the hydrophobic Pb–SHA complexes. These findings verify the great potential of surface modification for strengthening wolframite flotation.