Investigations on the selective depression of fenugreek gum towards galena and its role in chalcopyrite-galena flotation separation

To achieve the flotation separation of chalcopyrite from galena, a novel organic fenugreek gum (FG) with high water solubility was introduced as a galena depressant in this work. The effect of FG on the flotation separation of chalcopyrite from galena was investigated through micro-flotation tests, and the underlying mechanisms were further studied and discussed. Flotation results revealed that FG had a stronger depression effect towards galena than the traditional organic galena depressant dextrin. When 4 mg/L FG was added, galena was depressed intensively with the recovery less than 5% at the whole pH range tested from 2 to 11, while chalcopyrite recovery was always above 90%. Artificial mixed minerals flotation results further proved that FG could selectively depress galena flotation, and a concentrate with CuFeS2 grade of about 86% and recovery of around 96% was obtained from a feed material containing 48.35% CuFeS2 when 4 mg/L FG was added at pH 8.5. The results of the adsorption, zeta potential, and FTIR studies showed that FG was more inclined to adsorb on galena surface than chalcopyrite, and the pre-adsorbed FG on galena surface could further interfere with the following PAX coverage. XPS spectra analyses illustrated that the adsorption of FG on galena surface was physical, and hydrogen bonding was considered as the main driving force. Based on the results and analyses reported in this work, it can be concluded that FG has a potential to be a selective depressant to separate chalcopyrite from galena.

Automated summary

The novel organic fenugreek gum (FG) demonstrated a strong depression effect towards galena in the flotation separation of chalcopyrite from galena. It selectively depressed galena flotation, resulting in a high-grade and high-recovery CuFeS2 concentrate. The adsorption of FG on galena surface was found to be physical, driven mainly by hydrogen bonding, suggesting a potential for FG to be a selective depressant for separating chalcopyrite from galena.