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1

Research of nanobubbles enhanced reverse anionic flotation of a midlow grade phosphate ore

100%

Zhang T. , Zhang Q.

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tom Vol. 58, iss. 1

113--125

EN

The reverse anionic flotation is commonly used to upgrade the mid-low grade phosphate ore in China. The mineral characterization of raw ore shows that carbonate and phosphate minerals combined with fine intergrowth, difficulty in upgrading. Flotation using nanobubbles (NBs) can significantly enhance the flotation efficiency of fine particles of minerals. To research the effect of NBs on the flotation process of this phosphate ore, two flotation tests with and without NBs were compared. The results show that the MgO removal had an increment of 10% in the case of NBs flotation versus conventional flotation in the approximate grade and recovery of P2O5. The foam product of NBs flotation had smaller dimensions than the conventional flotation. NBs enhanced the contact angle on dolomite surface from 45.8° to 64.5°, and increases the d50 of dolomite from 20.49 µm to 30.43 µm.

2

Effect and mechanism on the flotation desulfurization of high-sulfur bauxite by using the mixed collector of PYDH

100%

Han L. , Zhang Q.

Physicochemical Problems of Mineral Processing

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2024

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tom Vol. 60, iss. 1

art. no. 183812

EN

Desulfurization of high sulfur bauxite is an important issue in Bayer alumina production. In this study, by using two anionic sulphydryl collectors (HX, HD) as mixed collectors (PYDH), the selectivity of flotation separation between pyrite and diaspore was improved, thereby reducing the sulfur content of high sulfur bauxite and ultimately meeting the production requirements of Bayer alumina. The findings showed that under the optimized conditions of 500 g/Mg collector, 150 g/Mg inhibitor, 200 g/Mg activator, 100 g/Mg foaming agent, and a slurry pH of 9, the sulfur content of bauxite can be reduced from 3.35% to 0.33% through one rough selection, one fine selection, and one scavenging flotation. Moreover, the interaction mechanism between mixed collectors and pyrite was studied through scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Zeta potential analysis, and contact angle testing. SEM-EDS research confirmed that PYDH adsorbed on the surface of pyrite. The contact angle measurement analysis showed that compared to individual collectors, pretreated pyrite with mixed collectors had better hydrophobicity. Zeta potential, FTIR, and XPS results indicated that PYDH selectively adsorbed pyrite through chemical adsorption. The mixed collector PYDH is an effective collector for pyrite in high sulfur bauxite flotation desulfurization.

3

Influence of measuring process properties on phosphate rock slurry rheology based on Brookfield method

100%

Chen A. , Zhang Q.

Physicochemical Problems of Mineral Processing

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2022

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tom Vol. 58, iss. 6

art. no. 156202

EN

This research aims to explore how the flotation process conditions influence the rheological properties of phosphate rock slurry. The apparent viscosity of phosphate rock slurry was measured by Brookfield DVNext rheometer. Different mineral types, grinding time, slurry mass concentration and reagent systems were adopted to study the viscosity behavior of phosphate rock slurry. The results showed that under the same conditions, the apparent viscosity of apatite and dolomite slurry was basically the same, and the apparent viscosity of the slurry after mixing the two minerals was basically the same as that of single mineral. For the same slurry concentration, the mineral particle size had a significant effect on the rheological behavior of the slurry, and its apparent viscosity increased exponentially with the decrease of particle size. In addition, phosphate rock slurry showed shear thickening fluids characteristics when the slurry concentration is 20%-40%, but changed to pseudoplastic fluid at high concentration (60%). Sulfuric acid as pH regulator and inhibitor had little effect on the rheology of slurry; when GJBW and NaOL were added as collectors, the rheology of slurry changed, and the effect of GJBW was more obvious.

4

Flotation separation of dolomite and apatite using polyaspartic acid as inhibitor

100%

Kang Y. , Zhang Q.

Physicochemical Problems of Mineral Processing

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2021

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tom Vol. 57, iss. 6

113--126

EN

In this paper, polyaspartic acid (PASP) was exploited as a novel dolomite depressant for flotation separation of apatite and dolomite. A series of tests with Zeta potential, FTIR and XPS were used to reveal the inhibitory mechanism of PASP on dolomite. The microflotation test illustrated that PASP has a strong inhibitory impact on dolomite, and little effect on the floatability of apatite in the pH range of 9-11. When using 2.7 Mg/L PASP as the depressant under sodium oleate (NaOl) system, the flotation recovery of dolomite dropped dramatically to 9.95%, and the recovery of apatite remained at about 88.27% at pH 10. Both dolomite and apatite have calcium ion on the surface. The calcium ion on the surface of apatite were strongly inhibited and repelled by the localized anions, while the important role on the surface of dolomite was positively charged magnesium ion and localized calcium species. PASP could ionize carboxylate ion under alkaline conditions, which could chemically chelate with the exposed metal ion and be adsorbed on the surface of dolomite. And then prevent the further adsorption of NaOl onto dolomite, which greatly weaken the floatability of dolomite and enhanced the flotation separation of the two minerals.

5

Effect of surface relaxation of rhodochrosite (104) and substitution of Mn by Ca on the electronic structure of rhodochrosite

80%

Zhang J. , Zhang Q. , Zhang T.

Physicochemical Problems of Mineral Processing

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2022

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tom Vol. 58, iss. 3

art. no. 145991

EN

To explore the difference between the surface and crystal structure of rhodochrosite, relaxation and reconstruction of the rhodochrosite (104) surface are studied by using Density Functional Theory. The calculation results indicated that the C and O atoms with lower reactivity tend to be enriched on the surface, while the Mn atoms with the highest reactivity moved away from the surface. The band gap width decreased from 1.814 eV to 1.614 eV after the formation of the rhodochrosite (104) surface. The electrons on the rhodochrosite (104) surface are more active than crystal. Ca substitution makes the atomic activity on the (104) surface of rhodochrosite more stable. Ca substitution reduces the ability of the surface of rhodochrosite to absorb external electrons, and the surface electrical properties decrease.

6

DFT study of coadsorption of fatty acid and kerosene on fluorapatite (001) surface

80%

Du W. , Li X. , Zhang Q.

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tom Vol. 59, iss. 1

art. no. 161890

EN

The adsorption of fatty acid, kerosene and fatty acid-kerosene on fluorapatite (001) surface were investigated by density functional theory (DFT) calculations. The results showed that the single fatty acid could form stable chemisorption on fluorapatite (001) surface by the O of fatty acids bonding with Ca1 site. The single kerosene could not be stably adsorbed on fluorapatite (001) surface because the H of kerosene did not form hydrogen bond with the O of PO43- on (001) surface (Osurf). For the coadsorption conformation, the chemisorption of fatty acid-kerosene on fluorapatite (001) surface was contributed by the interaction between O of fatty acids and Ca1, the H of kerosene did not bond with the Osurf, but the carbon chain length of kerosene has a large influence on the coadsorption. Compared with the coadsorption of fatty acid-decane, the adsorption of butyric acid-tetradecane and octanoic acid-tetradecane on fluorapatite (001) surface have greater adsorption energies and overlapping region of DOS between O 2p and Ca 4d, indicating that there is a synergistic effect between fatty acid and tetradecane. Meanwhile, the collaborative effects exist between the molecules of fatty acids. The interpenetrating adsorption of fatty acid and kerosene on the fluorapatite surface could improve the adsorption strength and density. The flotation test further confirmed that the single kerosene could not collect fluorapatite, but it could be collected by the single fatty acid. Besides, the synergistic effect between fatty acid and kerosene could increase the flotation recovery of fluorapatite.