Selective flotation separation of gypsum and quartz using dodecyl amine hydrochloride as collector: Mechanism and application

The selective flotation separation of gypsum and quartz in phosphogypsum (PG) is an urgent problem that is very important for the high‐value utilization of PG. In the work, dodecyl amine hydrochloride (DH) was introduced as a collector for the selective flotation separation of gypsum and quartz. The flotation property and selective mechanism of DH on the surface of gypsum and quartz were researched by single mineral flotation experiments, Fourier transform attenuated total reflection infrared spectroscopy analyzer, zeta potential analyzer, X‐ray photoelectron spectrum, molecular dynamic (MD) simulation, etc. Additionally, H+ was introduced into the mineral‐water system simulated by MD to take into account the effect of acidic conditions on the adsorption of DH. The pre‐adsorption of H+ on the quartz surface under strongly acidic conditions hindered the electrostatic force adsorption of DH on the quartz surface. Furthermore, DH was adopted as a collector in the direct flotation recovery of gypsum from PG, and the gypsum concentrates with productivity of 69.85%, CaSO4·2H2O content of 96.33%, and whiteness of 55.00% were obtained. The SiO2 content in the gypsum concentrate decreased from 9.08% to 0.616%. It suggested that DH could serve as a promising collector in the selective separation of gypsum and quartz in PG via flotation.