5-Heptyl-1,3,4-oxadiazole-2-thione: Synthesis and flotation mechanism to chalcopyrite

• Published in: Journal of industrial and engineering chemistry (Seoul, Korea) Vol. 61; pp. 331 - 339
• Main Authors: Huang, Yaoguo, Liu, Guangyi, Ma, Longqun, Liu, Jun
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 25.05.2018; 한국공업화학회
• Subjects: 5-Heptyl-1,3,4-oxadiazole-2-thione; Adsorption; Copper sulfide minerals; Flotation; 화학공학; Flotation; Copper sulfide minerals; Adsorption; 5-Heptyl-1,3,4-oxadiazole-2-thione
• ISSN: 1226-086X; 1876-794X
• DOI: 10.1016/j.jiec.2017.12.031

The hydrophobic mechanism of HpODT to chalcopyrite particles during froth flotation. [Display omitted] •An original 5-heptyl-1,3,4-oxadiazole-2-thione (HpODT) flotation collector.•HpODT possessed strong affinity to copper minerals flotation against pyrite.•Chalcopyrite adsorption of HpODT was an endothermic chemisorption.•CuS and CuN bonds co-exist in HpODT–Cu surface complexes.•HpODT–Cu surface complexes hydrophobized chalcopyrite flotation. In this article, 5-heptyl-1,3,4-oxadiazole-2-thione (HpODT) surfactant was synthesized and originally recommended as a collector for flotation recovery of chalcopyrite, bornite and pyrite. The micro-flotation findings indicated that compared with traditional collectors such as sodium isobutyl xanthate (SIBX) and sodium hexyl xanthate (SHX), HpODT possessed superior flotation affinity to chalcopyrite and bornite, and selectivity against pyrite under alkaline circumstances. After HpODT treatment, the contact angle of chalcopyrite increased, suggesting an improved hydrophobicity of chalcopyrite surfaces. Adsorption thermodynamic and kinetic analyses suggested that chalcopyrite adsorption of HpODT was a spontaneous-endothermic chemisorption process, and the ΔH (change of enthalpy), ΔS (change of entropy), ΔG (change of free energy) and Ea (activation energy) were 21.06kJmol−1, 173.63Jmol−1K−1, −30.77kJmol−1 (298K) and 20.19kJmol−1, respectively. The results of zeta potential hinted that HpODT chemisorbed on chalcopyrite surfaces. UV–vis spectra clearly observed that HpODT selectively reacted with Cu+ or Cu2+, not with Fe2+ or Fe3+ ions. FTIR spectra inferred that HpODT–Cu surface complexes were formed on chalcopyrite by reaction of HpODT’s CNNHC(S)O group with surface copper atoms to build CuS and CuN bonds.