Study On Dispersion Of Talc In The Flotation Of Sulfide Ores

The influences of various inevitably ions in the flotation of copper and nickel sulfide ores, inorganic adjusting reagents, surfactants and organic adjusting reagents on dispersion and congregation behaviors of talc samples with average particle size -0.01mm in diameter has been investigated by sedimentation tests, potentiodynamism and contact angle mesurement in this paper. Variation of the surface electrical property and wettability has been studied in absence and presence of reagents. Interaction energies between talc particles have been calculated by the extended DLVO theory and, additionally, the dispersion and congregation mechanism of talc in water has been researched.Results revealed that wetting angle of talc is 68° on lay, 58° on side, and PZC is 2.8~3.5 in water. Wettability is not changed with the variation of pH values, but the Zeta potential is sharply reduced when the pH value increased. Talc particals are still congregated when the Zeta potential is at -40mV.The presence of Cu~2+, Fe~3+ and Ni~2+ causes the congregation of talc particals and the shift of PZC to higher value, while the wetting angles is not varied. The PZC of talc shifts to 8, 8.8 and 7.6 when the concentrations of Cu~2+, Ni~2+ and Fe~3+ are 4×10~-4 mol.L~-1, respectively.Sodium fluorosilicate, sodium dodecyldenzenesulfonate(DBS) and sodium lauric acid exhibit some effects on dispersion of talc particals in liquid, and the dispersion ratios increase 3%~5% approximately. None of the three reagents alters the hydrophobicity of the mineral, but all of them enhance the absolute value of the Zeta potential.Sodium carboxymethyl cellulose(CMC) exhibits better dispersion effect than other reagents. Dispersion ratio of talc increased 8.1% in 100mg.L~-1 CMC solutions under pH 10.5. The original hydrophobic surface of talc mineral become hydrophilic in the presence of CMC, the wetting angles decreased from 68° to 32°on lay, and 58° to 28° on side, and the absolute value of zeta potential also increased. The mixing of CMC with sodium fluorosilicate or sodium lauric acid led to further increacement of the dispersion ratio.The calculation of interaction energies indicated that surface hydrophobic energy appeared to be the major determinaton of the dispersionor congregation behavior of the talc particles in aqueous solutions. Dispertion ratio has been little affected if only increasing the electrostatic interaction energy. Therefore, the overcoming of the hydrophobic energy is the key to stable dispersion of talc particles.