A novel combined collector with superior selectivity for flotation separation of lepidolite from feldspar: Experimental insight and MD simulation

In this study, the cationic collector dodecylamine (DDA) and anionic collector sodium dodecyl diphenyl ether disulfonate (SLDED) were used for the flotation separation of lepidolite from feldspar, and the adsorption mechanism on the surface of two minerals were analyzed and determined. Lepidolite and feldspar could not be separated using a single collector DDA or SLDED, but could be separated well using the combined collector DDA + SLDED. The synergistic effect between DDA and SLDED was verified using the surface tension calculation results. The contact angle and zeta potential measurements verified that DDA could be adsorbed well on the surface of lepidolite and feldspar, enhancing surface hydrophobicity. SLDED had poor adsorption on the surface of lepidolite and feldspar, and had little effect on the hydrophobicity and floatability. The combined collector DDA + SLDED could improve the flotation separation efficiency of two minerals by reducing the adsorption of DDA on the surface of feldspar. X-ray photoelectron spectrum, Fourier-transform infrared spectroscopy and molecular dynamics simulations showed that the addition of SLDED promoted the transfer of more DDA from the solution to lepidolite but it reduced the adsorption of DDA on feldspar. Therefore, the adsorption of combined collector DDA + SLDED enhanced the hydrophobicity of the surface of lepidolite and weakened the hydrophobicity of the surface of feldspar, thus contributing to the flotation separation process of lepidolite and feldspar.