Gemini Silicone Flotation Synthetic Aluminum Silicate Minerals Flotation Performance

Gemini organosilicon surfactants, FGS-2, FGS-4 and FGS-6 were synthesized by silane SCA-1902, hexamethyldisiloxane MM and dibromoalkane through SN2 reaction. Infrared spectra, GC-MS and NMR analysis were studied to illustrate the structure of the products, and the results were agreed well with the expected ones;HPLC analysis showed that the purity of the three products were 85.77%,87.92% and 92.26%, respectively.The flotation behaviors of the main gangue minerals in bauxite ores-kaolinite, pyrophyllite and illite with a series of Gemini organosilicon collectors were studied.The pure mineral flotation experiments show that all of the three Gemini organosilicone cationic collectors FGS-2,FGS-4 and FGS-6 exhibit strong flotation capability on kaolinite, pyrophyllite and illite over a wide pH range, and the recovery of the three aluminosilicate minerals is higher in alkaline condition than in acid condition, especially in strong alkaline condition pH=12.The collecting capability of the three collectors is in the order of FGS-6>FGS-4>FGS-2.Using Gemini organosilicon surfactants as collectors, with the concentration of 6×10-4 mol/L and pH=9.5,the flotation recoveries of the three aluminosilicate minerals are all up to 90%.The adsorption mechanism of the new collectors on the three aluminosilicate minerals has been investigated through Zeta-potential and IR spectrum measurements. Zeta-potential measurement indicates that the PZC (Point of Zero Charge) of kaolinite, pyrophyllite and illite are 3.5,2.3 and 3.0 respectively, and theζ-potential of kaolinite, pyrophyllite and illite shows a pronounced shift towards more positive zeta potentials in the presence of the collector. The IR spectrum of clay minerals treated by FGS-4 both exhibit new peaks around at 3000～2800 cm-1,which previously attributes to the stretching bands of-CH3 and-CH2, and no other peak shift was observed. So it can be concluded that the adsorption between Gemini organosilicon collector and the three aluminosilicates is dominated by physical electrostatic adsorption.