Alkyl Guanidine Sulfate Series Flotation Of Synthetic Aluminum Silicate Minerals Flotation Performance

In order to solve the problem in alumina production, it is important to take a new collector of reverse flotation for improving the Al/Si (mass ratio of Al₂O₃ to SiO₂) of diasporic bauxite in China. In this paper, the synthesis of alkyl-guanidine sulfates and its flotation properties to diaspore, kaolinite, pyrophyllite and illite have been started. The adsorption mechanism of the new collectors on the four minersls has been investigated through contact angle, Zeta potential and IR spectrum measurements.Four alkyl-guanidine sulfates, the SAG₆, SAG₈, SAG₁₀ and SAG₁₂ were synthesized by O-methyl isourea sulfate with relevant alkylamine. The molecular structures of synthesized products have been identified by IR spectrum, element analysis and melting point measurements.The results of flotation tests indicate that the collecting ability of alkyl-guanidine sulfates for diaspore, kaolinite and illite is in the order of SAG₁₂≈SAG₁₀≈SAG₈>SAG₆, and that for pyrophyllite is in the order of SAG₁₂>SAG₁₀≈SAG₈>SAG₆. The collecting ability and selectivity of SAG₁₂ are better than 1231 and DDA. Using alkyl-guanidine sulfates as collector, in the condition of acidity, four minerals all have good flotation recovery. However, in the condition of strong alkalescence, the flotability of diaspore decreases notablely, and the three silicate minerals still keep a relatively high flotation recovery. Therefore, at the condition of strong alkalescence, it is possible to separate the diaspore from the silicate minerals such as kaolinite, pyrophyllite and illite using alkyl-guanidine sulfates as collector.The PZC (Point of Zero Charge) of diaspore, kaolinite, illite and pyrophyllite are pH 6.0, 3.5, 3.0 and 2.3 respectively. The results of contact angle measurement show that the natural flotability of aluminum silicate minerals is in the order of pyrophy llite> kaolinite≈illite>> diaspore. The alkyl-guanidine sulfates can improve the hydrophobicity of the four minerals. Zeta potential and IR spectrum measurements approve that the interaction between alkyl-guanidine sulfates and aluminum silicate minerals are electrostatic adsorption and hydrogen bond.