A self-assembly mixed collector system and the mechanism for the flotation separation of spodumene from feldspar and quartz

Abstract

The mixture of dodecylamine (DDA) and α-bromododecanoic acid (α-BDDA) was used as a collector to separate spodumene from feldspar and quartz. It was found that at the condition of molar ratio of DDA: α-BDDA 1:19, the collector concentration 0.500 mmol/L, and pH 7.1, the recoveries of spodumene, feldspar, and quartz were 85.90%, 4.48%, and 3.92% respectively in single mineral micro-flotation experiments. A concentrate with a recovery of 80.00% and a Li2O grade of 6.40% was achieved at the condition of molar ratio of DDA: α-BDDA 1:19, collector concentration 0.430 mmol/L and pH 6.0 in the artificial-mixed-ore micro-flotation experiments. Meanwhile, different flotation behaviors caused by different adding sequence of flotation reagents indicated that DDA could form self-assembly structure with α-BDDA. The separation and adsorption mechanism was investigated by atomic force microscopy, contact angle, zeta potential, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy measurements and turbidity testing. The results revealed that the adsorption of the DDA/α-BDDA obviously increased the hydrophobicity of spodumene, thus led to higher recovery of spodumene. But the DDA/α-BDDA had no significant effect on the hydrophilicity of feldspar and quartz, nor on their contact angles. Thus, feldspar and quartz were sank as tailings. The DDA/α-BDDA was adsorbed on the surface of spodumene by chemisorption, and the main active sites on spodumene to react with the DDA/α-BDDA were Al. The DDA/α-BDDA was a potential selective and efficient collector to separate spodumene from feldspar and quartz at litmusless condition.