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Enhanced sulfidation of chrysocolla with ammonium carbamate and its effect on flotation

Wang Ziang, Wu Dandan, Cao Jing, Chen Huiqin

Physicochemical Problems of Mineral Processing

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2023

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Vol. 59, iss. 3

atr. no. 168573

EN

In this study, flotation experiments, zeta potential, XPS, AFM, SEM-EDS, and contact angle measurements were performed to study the influence of ammonium carbamate (CH6N2O2) on the sulfidation flotation of chrysocolla. The results of the sulfidation flotation experiments showed that the recovery of chrysocolla increased more than 40% on the optimal condition after adding ammonium carbamate. In addition, the zeta potential of samples with ammonium carbamate was clearly higher than ores for pH > 6, which was due to the complexation reaction between ammonium carbamate and copper ion on the surface of chrysocolla samples. The activity of copper adsorption has also been improved. Furthermore, the XPS data indicated that the content of Cu-S compounds on the mineral surface has been significantly enhanced after ammonium carbamate complex sulfidation. The chemical analysis of the solution led to the same conclusion. The AFM results showed that ammonium carbamate had a positive impact on the adsorption of minerals surface, and increased the flotation recovery. It can be deduced from the SEM-EDS analysis that the surface of chrysocolla better combined with S-, and more Cu-S components were generated on the surface, which led to 1.04% increase of S atomic concentration. Finally, the contact angle measurements showed that the water contact angle of chrysocolla after adding ammonium carbamate could reach 90.4°, which proved that the sulfidation improved the floatability of the chrysocolla sample.

2

Synthesis of a novel hydroxamic acid flotation collector and its flotation separation of malachite against quartz

Sun Xin, Huang Lingyun, Wu Dandan, Hu Bo, Zhang Mei, Li Yaming, Tong Xiong

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 4

art. no. 149427

EN

This paper proposes a promising chelating collector, phenyl propyl hydroxamic acid (BPHA), to directly float malachite for the separation of malachite against quartz. The flotation performance and mechanism was investigated via microflotation tests, as well as through contact angle, Scanning Electron Microscopeand Energy Dispersive Spectrometer (SEM–EDS), zeta potential, adsorption capacity, Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) analyses. The results of microflotation tests showed that BPHA has a strong ability to collect malachite and a significant selectivity against quartz. The contact angle tests showed that BPHA effectively adsorbed onto the mineral surface and could improve the hydrophobicity of the malachite surface. SEM–EDS and adsorption capacity analyses further indicated that BPHA adsorbed onto the surface of malachite. The FR-IR results suggested that BPHA could react with Cu2+ ions and facilitate strong chemical adsorption onto the surface of malachite. Furthermore, zeta potential and XPS analyses provided clear evidence that BPHA exhibited a stronger affinity for malachite and a weaker interaction with quartz.

3

DFT and TOF-SIMS study of the interaction between hydrogen sulfide ion and malachite (–201) surface

Mao Yingbo, Wu Dandan, Huang Lingyun

Physicochemical Problems of Mineral Processing

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2021

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Vol. 57, iss. 5

71--79

EN

In this paper, the mechanism of interaction between hydrogen sulfide ions and malachite was investigated using density functional theory (DFT) calculations and time of flight secondary ion mass spectrometry (TOF-SIMS). The DFT calculations showed that HS− adsorption on the malachite (−201) surface was stronger than that of S adsorption resulting from the higher number of electron transfers in the solution which accelerated the sulfidation reaction rate. Density of states (DOS) analysis showed that the near Fermi level was jointly contributed to by the Cu 3d, O 2p, O 2S, and S 3P orbits after adsorption of HS− on the malachite (–201)surface. It was found that the 2p orbital of O and the 3p orbital of S overlapped, indicating that S not only reacted with Cu, but also with O. The TOF-SIMS detected S− and CuS2− fragment ion peaks in the 0−150 m/z negative segment of mass spectra. TOF-SIMS also showed that copper sulfide films of certain thicknesses were formed, demonstrating the effectiveness of hydrogen sulfide sulfidation in flotation processes.

4

Dissolution kinetics of hemimorphite in methane sulfonic acid

Zhang Qian, Wen Shuming, Feng Qicheng, Nie Wenlin, Wu Dandan

Physicochemical Problems of Mineral Processing

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2019

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Vol. 55, iss. 1

1--9

EN

Hemimorphite has a large content of zinc, but its recovery using flotation alone is low. Nowadays, hydrometallurgical and pyrometallurgical methods are used to treat zinc ores. In this work, the leaching and dissolution kinetics of hemimorphite by using methane sulfonic acid (MSA) as an alternative leaching reagent was investigated. The effects of several experimental parameters including reaction temperature, MSA concentration, particle size, and stirring speed were also analyzed. Results showed that zinc leaching increased with increased reaction temperature, MSA concentration, and stirring speed, as well as decreased particle size. The mechanism of hemimorphite dissolution in MSA solutions may be a new variant of the shrinking-core model. Based on experimental data and kinetics, the apparent activation energy was determined to be 49.50 kJ/mol. The rate of reaction equation was also obtained to describe the process and found that the MSA concentration largely influenced the leaching of hemimorphite.