The low-carbon flotation separation of chalcopyrite from pyrite with a fire-new alkylamine-triazine-dithiol collector

Abstract

Lowering lime consumption in froth flotation is one of the important aspects for carbon emission reduction. Herein, 6-butylamino-1,3,5-triazine-2(1H)-thione-4-thiol sodium (BN) was pioneeringly designed as a high-selective collector for copper sulfide flotation. The micro-flotation findings indicated that BN realized an effective separation of chalcopyrite from pyrite under pH ∼ 8.0. The further mechanism investigations through adsorption kinetics and thermodynamics, density functional theory (DFT) calculation, FTIR, UV and XPS suggested that BN self-assembled on chalcopyrite to generate the surface Cu-BN complexes where the CuS bonds were formed. Meanwhile, BN’s butyl group oriented outward for attaching bubbles to improve the floatability of chalcopyrite. In comparison to isobutyl xanthate anion (IBX−), BN anion (BN−) possesses the big conjugated configuration of amino-triazine dithiol group and strong electron delocalization ability. Moreover, BN− exhibited the stronger electron-accepting and weaker electron-donating ability than IBX−, which made BN− exhibit a strong affinity towards Cu(Ⅰ)/Cu(Ⅱ) atom(s) on chalcopyrite surface and weak interaction to Fe(Ⅱ)/Fe(Ⅲ) atom(s) on pyrite surface. Therefore, the pH for flotation separation of chalcopyrite against pyrite with BN was much lower than that with sodium isobutyl xanthate, reducing lime consumption and carbon emission.