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[Display omitted] • TA, a biodegradable plant polyphenol, was introduced as a depressant in the flotation separation of chalcopyrite and talc. • TA could be selectively adsorbed on the surface of talc to separate talc and chalcopyrite. • The interaction of TA with talc was physical rather than chemical. • The layered structure of talc and the phenolic hydroxyl structure of TA cause TA to selectively adsorb on talc surface. In this paper, the effect of Tannic acid (TA), a green, biodegradable plant polyphenol, as a talc depressant on the separation behavior of talc and chalcopyrite was investigated. The results of micro-flotation studies revealed that at a TA dosage of 20 mg/L at pH 7, talc recovery was barely 10 % whereas chalcopyrite recovery remained above 90 %, indicating that TA can selectively depress talc flotation. The results of the artificial mixed minerals test further confirmed the depressive effect of TA. The adsorption results showed that the adsorption density of TA on talc was greater than that on chalcopyrite surface. Similar conclusions were observed in zeta potential tests. It is noteworthy that the zeta potential of the chalcopyrite treated with TA and butyl xanthate sodium continued to shift negatively in comparison to the zeta potential of chalcopyrite treated with TA alone, suggesting that butyl xanthate sodium can continue to adsorb on the surface of chalcopyrite following TA treatment. Besides, X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy tests concluded that TA adsorbs on talc surface by physical (hydrophobic) interaction. Differences in the crystal structures of chalcopyrite and talc, as well as the large number of phenolic hydroxyl structures contained in TA, are the main driving forces for the selective adsorption of TA on the talc surface. This work provides an insight to the selection of inhibitors for the separation of chalcopyrite and talc, particularly from the perspective of the hydrophobic effect of the talc layered structure. [ABSTRACT FROM AUTHOR]

[Display omitted] • The method of promoting ilmenite flotation involves adding BHA to the mill was proposed. • The BHA synergistic mechanical activation can promote ilmenite flotation significantly. • The mechanism of BHA synergistic mechanical activation on ilmenite flotation was revealed. In this paper, the effect of the benzohydroxamic acid (BHA) synergistic mechanical activation on ilmenite flotation was systematically investigated. Flotation results revealed that the flotation recovery of ilmenite significantly increased with the addition of BHA before grinding as compared to the conventional process flow. Similar trend was observed in the flotation test of artificial mixed mineral. The addition of BHA to the mill has little effect on the size distribution of ilmenite, but it can increase the content of crystal surface (1 0 4) with the lowest surface energy of ilmenite. The results of Fourier-transform infrared spectroscopy (FT-IR) analysis showed that the addition of BHA before grinding resulted in improving the intensity and kinds of characteristic absorption peaks of BHA on the ilmenite surface. The addition of BHA to the mill effectively facilitated the interaction between ilmenite and BHA. Besides, the result of flotation kinetics demonstrated that the flotation kinetics of ilmenite could be well evaluated with the first-order kinetic model. And the flotation kinetic constant was improved by adding BHA before grinding, which was conducive and beneficial for enhancing the ilmenite flotation. [ABSTRACT FROM AUTHOR]

In this study, a novel method of promoting cassiterite flotation involves adding Pb-BHA (Pb(NO 3) 2 -benzohydroxamic acid) complexes to the cassiterite grinding process was investigated. The flotation result showed that adding Pb-BHA complexes before grinding had a marked effect on the cassiterite flotation recovery. The cassiterite flotation recovery with Pb-BHA complexes added before grinding was higher 42.80% than that of Pb-BHA complexes added after grinding. Moreover, it revealed a similar trend for artificial mixed minerals of cassiterite and quartz, in which the Sn recovery and grade of concentrate increased by 34.71% and 1.11%, respectively. The Fourier-transform infrared spectroscopy (FT-IR) analysis revealed that adding Pb-BHA complexes before grinding enhanced the adsorption of Pb-BHA complexes on the cassiterite surface. And the X-ray photoelectron spectroscopy (XPS) analysis demonstrated that the chemical environment of N in Pb-BHA complexes was changed in the grinding, making it more easily to adsorb on cassiterite surface. [Display omitted] • Adding Pb-BHA before grinding has a marked effect on the cassiterite flotation. • The Pb-BHA were chemically adsorbed on the cassiterite surface. • The chemical state of N was changed in grinding, promoting cassiterite flotation. [ABSTRACT FROM AUTHOR]