Studies On Effect Of CPC And Sodium Oleate On The Floatability Of Aluminum-Silicon Minerals Of Different Particle Size And Its Mechanism

Pure specimens of diaspore, kaolinite, illite and pyrophyllite were studied as the subjects in this paper. The effect of pulp pH and dosage of sodium oleate and CPC (cetylpyridinium chloride) on flotation behavior of four fractions(-0.15mm+0.1mm,-0.1mm+0.075mm,-0.075mm+0.045mm and-0.045mm)of the four minerals was investigated. Zeta potential, adsorption capacity, contact angle and EDLVO theory calculation were used to exam the mechanism of the agents on aluminum-silicon minerals and the reason of floatability.The results of flotation showed that:under the sodium oleate flotation system, with the increase of the pH, the recovery of the four minerals increased and then decreased, when the minerals became finer, the diaspore had better floatability, while-0.045 mm size of three silicate minerals had worse floatability than the other three sizes, and the other three sizes had the same floatability. With the increase of the reagent dosage, when the pH was about 5,the recovery of four fraction of four minerals all increased and then basically remained unchanged; when the pH was about 9, the recovery of the four fraction of diaspore increased rapidly, while three silicate minerals in-0.045 mm size had well floatability, and the floatability of the other three sizes was bad.Under the cetylpyridinium chloride flotation system, with the increase of the pH, the recovery of diaspore increased but the recovery of the others decreased. When the minerals became finer, the diaspore had better floatability, while three silicate minerals had worse floatability. With the increase of the reagent dosage, when the pH was about 5,-0.045 mm size of diaspore's recovery basically maintained at about 40%, three silicate minerals'floatability was poorer; for the other three fraction, diaspore basically could not be floated, three silicate minerals'recovery increased rapidly and then remained unchanged; when the pH was about 8,the-0.045 mm size of diaspore's recovery had small increase, and the recovery of three silicate minerals grew slowly. For the other three sizes, the recovery of diaspore grew slowly, and three silicate minerals' recovery grew rapidly. The results of zeta potential and contact angle showed that there was hydrogen-bonding and electrostatic force between flotation reagent and minerals.The adsorption of cetylpyridinium chloride made the zeta potential of the four minerals increase, however, the adsorption of sodium oleate lowered the zeta potential.After interacting with the reagent, the contact angle of the four minerals all increased, which made the floatability be better.The results of adsorption capacity showed that the adsorptive capacity sequence of aluminum-silicon minerals to cetylpyridinium chloride was:illinite≈kaolinite≈pyrophyllite>iaspore;when the minerals became finer, the adsorption capacity of diaspore was better and three Silicate minerals'was the same in all sizes.EDLVO theory calculation showed that under the sodium oleate solution, in acidic conditions, it was attractive force between diaspore and kaolinite particles making them adsorb and agglomerate each other, the separation between them was bad; while in alkaline conditions, when the distance between the particles was less than 5nm, there was attractive force; when the distance between the particles was more than 5nm, the repulsive force made them maintain decentralized state, the separation between them was well,and the separation of coarse particles was better than that of the fines.Under the cetylpyridinium chloride solution, in acidic and alkaline conditions, the force between particles was repulsive force which made the separation be well,and the separation of coarse particles was better than that of the fines.The dissertation was supported by "National Key Basic Research Program (973)"(2005CB623701).