Abstract:

Talc usually exists as gangue mineral in copper-nickel sulfide, molybdenite etc. In order to separate precious metals, naturally hydrophobic talc should be depressed effectively in flotation process. The effect of fenugreek-gum (FG) on the flotation performance of talc with different particle sizes was studied. The depression mechanism was investigated extensively through tests of flotation, adsorption and zeta potential, as well as infrared spectroscopy and laser particle size analysis. Flotation results indicated that the FG had a strong depression ability for talc with particle size of - 0.074 + 0.037 mm, -0.037 mm and -0.010 mm when proper dosage of FG was added. The coarse talc was completely depressed by 2.5 mg/ dm3 FG. When particle size decreased, more FG was required to obtain maximum depressing effect, which was verified by adsorption tests. FG reduced the electronegativity on the talc surface by chemical adsorption, and flocculation of talc powders caused a high efficient depressing effect.

Conclusion:

In this work, the effect of fenugreek-gum (FG) on the depression of talc with different particle sizes and the depression mechanism were systematically investigated. The floatability of talc was influenced by the granularity, and the floatability of talc in different particle sizes followed the order: -0.074+0.037mm > -0.037mm > -0.010mm. FG had a strong depressing effect on talc, especially for coarse talc, the -0.074+0.037mm size fraction of talc was completely depressed by 2.5 mg/ dm3 FG. The depressing effect of FG for talc was influenced by particle size. Larger dosage of FG was needed in order to completely depress talc with smaller particle size. The absolute value of talc surface charge and the inter-particle repulsion decreased in the presence of FG, causing easier inter-particle flocculation. FG interacted with talc surface by chemical adsorption.