Selective Flotation of Rutile from Chlorite Using a Combined CMC and SSF Depressant in a Benzohydroxamic Acid Collector System.

Chlorite is a common gangue mineral in primary rutile ores, which poses challenges for selective flotation. This study evaluates the depression performance of sodium fluosilicate (SSF), carboxymethyl cellulose (CMC), and their combination (CMC+SSF) in a benzohydroxamic acid flotation system. Pure mineral flotation tests demonstrate that the individual depressants exhibit limited selectivity, whereas the CMC+SSF combination significantly enhances chlorite depression, achieving a rutile-chlorite recovery difference of 71.85 percentage points. To elucidate the depression mechanisms, a comprehensive set of characterization techniques was employed, including ζ potential analysis, contact angle measurements, FTIR spectroscopy, adsorption quantification, and X-ray photoelectron spectroscopy (XPS). The results indicate that the combined depressants selectively adsorb onto chlorite via chemical interaction and hydrogen bonding, effectively blocking active sites and reducing their recovery. These insights highlight the synergistic role of the CMC and SSF in enhancing the efficiency of rutile flotation.