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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]

A novel flotation depressant with selective adsorption properties based on orbital matching was used to replace cyanide for the flotation separation of jamesonite and marmatite. The presence of characteristic groups, such as the sulfhydryl and amino groups, enhanced the adsorption of DL-cysteine on the metal ions (Zn2+ and Fe2+) on marmatite surface. The adsorption of DL-cysteine on the marmatite surface significantly enhanced the surface hydrophilicity and decreased the flotation recovery. [Display omitted] • DL-cysteine is a potential green depressant for marmatite flotation. • DL selectively depressants marmatite but has little effect on jamesonite floatability. • The adsorption between DL and marmatite hinders DDTC adsorption. • Coordination theory analysis confirmed the complexation between DL and Fe2+/Zn2+. Flotation is an effective separation technique for removing marmatite, a harmful impurity, from jamesonite. In this study, DL-cysteine (DL) was used as an eco-friendly flotation agent for the targeted separation of jamesonite from marmatite. Micro-flotation experiments, zeta potential measurement, Fourier transform infrared, and X-ray photoelectron spectroscopies show that DL can combine with metal ions on the surface of marmatite through chemical complexation, thereby selectively hindering the flotation of marmatite. The competitive adsorption of DL and sodium diethyldithiocarbamate on marmatite surface is the main factor leading to the change in marmatite floatability. The flotation coordination theory confirms that Fe2+ is the main active site on marmatite surface. π-back-bonding and σ-bonding are the main driving forces for the adsorption of DL on marmatite surface. Importantly, DL can be produced using animal hair as a raw material. It is, thus, a low-cost material with good environmental compatibility and high selectivity and a potential green depressant for marmatite flotation. [ABSTRACT FROM AUTHOR]

The selective interaction of reagents with mineral surfaces is the core basis for mineral flotation separation. Herein, the interaction mechanism of a novel depressant m-nitrobenzoate with arsenopyrite has been investigated with the help of density functional theory (DFT) simulations, supplemented by micro-flotation tests and X-ray photoelectron spectroscopy (XPS) analyses. It is found that the adsorption of m-nitrobenzoate on the surface of arsenopyrite was mainly due to the effect of –NOO– in m-nitrobenzoate. These findings provide a clear correlation between the experiments and DFT, indicating that the –NOO– in m-nitrobenzoate can adsorb on the surface of arsenopyrite via a covalent bond, thereby realizing the depress of arsenopyrite. [Display omitted] • The oxidative properties of the -NOO- exacerbate the oxidation of arsenopyrite. • The presence of π-back bonding favors the interaction between ligands and metal ions on the mineral surface. • The lone pair of electrons of the depressant gives the empty orbital of the surface metal ion to form a positive σ bond. [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]