In order to improve the scheelite flotation with sodium oleate(NaOL),the effect of a non-ionic polyoxyethylene ether(JFC-5)on the floatability of scheelite was investigated through flotation experiments at10°C,co...In order to improve the scheelite flotation with sodium oleate(NaOL),the effect of a non-ionic polyoxyethylene ether(JFC-5)on the floatability of scheelite was investigated through flotation experiments at10°C,compared with60mg/L NaOL alone,the recovery of scheelite is improved from22%to85%in the presence of JFC-5with a mass ratio of20%at pH10.Moreover,the resistance to Ca2+of NaOL is increased.The adsorption mechanism was analyzed by zeta potential measurement,contact angle measurement and X-ray photoelectron spectroscopy(XPS)analysis.The results show that the adsorption of NaOL on scheelite surface is enhanced after adding JFC-5due to the more negative zeta potentials and larger contact angles of scheelite.And the co-adsorption of NaOL and JFC-5is confirmed by XPS analysis,so it is indicated that the adsorption of JFC-5decreases the electrostatic repulsion between the oleate ions,resulting in the stronger adsorption of NaOL on scheelite surface.In short,the mixed NaOL/JFC-5collector can effectively improve scheelite flotation.展开更多
Cardanol polyoxyethylene ether is a kind of nonionic surfactants based on natural raw materials, with good surface activity and resistance to hard water. At 25 ℃, the value of critical micelle concentration （CMC） i...Cardanol polyoxyethylene ether is a kind of nonionic surfactants based on natural raw materials, with good surface activity and resistance to hard water. At 25 ℃, the value of critical micelle concentration （CMC） is 6.09×10-6 mol/L, and the lowest surface tension （TcMc） is 38.08 mN/m. Moreover, cardanol polyoxyethylene ether has strong salt tolerance to monovalent inorganic salts; with the increase of concentration of divalent inorganic salt, the surface activity of cardanol polyoxyethylene ether is enhanced. The effect of monohydric alcohol on the surface activity of cardanol polyoxyethylene ether is complex： the ability of BGF-10 to form micelles increases and then decreases with the increase of the concentration of monohydric alcohol, cardanol polyoxyethylene ether has a synergistic effect with anionic, nonionic and cationic surfactants, especially with hexadecyltrimethylammonium bromide （CTAB）, and its critical micelle concentration is decreased by 2.52%, while the surface tension is decreased by 11.49%. Test results also show, comparing to nonylphenol polyoxyethylene ether, the emulsifying and the thickening performances of cardanol polyoxyethylene ether are better, and its foam performance is lower. Also, the cloud point of cardanol polyoxyethylene ether is higher than nonylphenol polyoxyethylene ether. In most case, the detergency of cardanol polyoxyethylene ether is better than or equivalent to nonylphenol polyoxyethylene ether. cardanol polyoxyethylene ether is an excellent alternative to nonylphenol polyoxyethylene ether in detergents.展开更多
Spin-lattice relaxation time, spin-spin relaxation time and two-dimensional nuclear Overhauser enhancement spectroscopy (2D NOESY) experiments of polyoxyethylene lauryl ether (Brij-35) micelles in aqueous solutions at...Spin-lattice relaxation time, spin-spin relaxation time and two-dimensional nuclear Overhauser enhancement spectroscopy (2D NOESY) experiments of polyoxyethylene lauryl ether (Brij-35) micelles in aqueous solutions at a concentration of 100 times the critical micellar concentration (cmc) give direct evidence that the hydrophilic polyoxyethylene chains, staying in the exterior of the micellar core, are coiled, bent and aligned around the micellar core with a certain number of water molecules included. This hydrophilic layer is in contact with the solvent, water, keeping the micellar solution stable. 1H NMR relaxation time measurements show that the first oxyethylene group next to the alkyl chain participates in the formation of the surface area of the micellar core. The motion of the hydrophilic polyoxyethylene chains is less restricted as compared with the hydrophobic alkyl chains.展开更多
基金Project(2016RS2016)supported by Hunan Provincial Science and Technology Leader(Innovation Team of Interface Chemistry of Efficient and Clean Utilization of Complex Mineral Resources)China
文摘In order to improve the scheelite flotation with sodium oleate(NaOL),the effect of a non-ionic polyoxyethylene ether(JFC-5)on the floatability of scheelite was investigated through flotation experiments at10°C,compared with60mg/L NaOL alone,the recovery of scheelite is improved from22%to85%in the presence of JFC-5with a mass ratio of20%at pH10.Moreover,the resistance to Ca2+of NaOL is increased.The adsorption mechanism was analyzed by zeta potential measurement,contact angle measurement and X-ray photoelectron spectroscopy(XPS)analysis.The results show that the adsorption of NaOL on scheelite surface is enhanced after adding JFC-5due to the more negative zeta potentials and larger contact angles of scheelite.And the co-adsorption of NaOL and JFC-5is confirmed by XPS analysis,so it is indicated that the adsorption of JFC-5decreases the electrostatic repulsion between the oleate ions,resulting in the stronger adsorption of NaOL on scheelite surface.In short,the mixed NaOL/JFC-5collector can effectively improve scheelite flotation.
文摘Cardanol polyoxyethylene ether is a kind of nonionic surfactants based on natural raw materials, with good surface activity and resistance to hard water. At 25 ℃, the value of critical micelle concentration （CMC） is 6.09×10-6 mol/L, and the lowest surface tension （TcMc） is 38.08 mN/m. Moreover, cardanol polyoxyethylene ether has strong salt tolerance to monovalent inorganic salts; with the increase of concentration of divalent inorganic salt, the surface activity of cardanol polyoxyethylene ether is enhanced. The effect of monohydric alcohol on the surface activity of cardanol polyoxyethylene ether is complex： the ability of BGF-10 to form micelles increases and then decreases with the increase of the concentration of monohydric alcohol, cardanol polyoxyethylene ether has a synergistic effect with anionic, nonionic and cationic surfactants, especially with hexadecyltrimethylammonium bromide （CTAB）, and its critical micelle concentration is decreased by 2.52%, while the surface tension is decreased by 11.49%. Test results also show, comparing to nonylphenol polyoxyethylene ether, the emulsifying and the thickening performances of cardanol polyoxyethylene ether are better, and its foam performance is lower. Also, the cloud point of cardanol polyoxyethylene ether is higher than nonylphenol polyoxyethylene ether. In most case, the detergency of cardanol polyoxyethylene ether is better than or equivalent to nonylphenol polyoxyethylene ether. cardanol polyoxyethylene ether is an excellent alternative to nonylphenol polyoxyethylene ether in detergents.
基金This work was supported by the National Key Basic Research Development Program "Fundamental Studies of the Extensively Enhanced Petroleum Recovery" (Grant No. G199022504) .
文摘Spin-lattice relaxation time, spin-spin relaxation time and two-dimensional nuclear Overhauser enhancement spectroscopy (2D NOESY) experiments of polyoxyethylene lauryl ether (Brij-35) micelles in aqueous solutions at a concentration of 100 times the critical micellar concentration (cmc) give direct evidence that the hydrophilic polyoxyethylene chains, staying in the exterior of the micellar core, are coiled, bent and aligned around the micellar core with a certain number of water molecules included. This hydrophilic layer is in contact with the solvent, water, keeping the micellar solution stable. 1H NMR relaxation time measurements show that the first oxyethylene group next to the alkyl chain participates in the formation of the surface area of the micellar core. The motion of the hydrophilic polyoxyethylene chains is less restricted as compared with the hydrophobic alkyl chains.
