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1
Content available 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.
2
Content available New insights into the promotion mechanism of (NH4)2SO4 in sulfidization flotation: a combined experimental and computational study
Chen Daixiong, Liu Mengfei, Hu Bo, Dong Yanhong, Xue Wei, He Peng, Chen Fang, Zhu Jianyu, Zhang Chenyang
Physicochemical Problems of Mineral Processing
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2021
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Vol. 57, iss. 5
57--70
EN
Ammonium sulfate ((NH4)2SO4) exhibits promoting effects in malachite sulfidization flotation. However, the promotion mechanism remains poorly understood. In this study, micro-flotation tests, zeta-potential measurements, scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM-EDS), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and materials studio simulation (DFT) were used to investigated the promotion mechanism of (NH4)2SO4. Micro-flotation test demonstrates that the recovery of malachite from 73% increased to 83%, when the (NH4)2SO4 was added. Contact angle and zeta potential test results indicate that addition of Na2S•9H2O changes the surface properties of malachite and provide the conditions for adsorption of butyl xanthate (BX). After promoting the sulfidization by (NH4)2SO4, BX is more effective in improving the hydrophobicity. SEM-EDS and AFM results show that (NH4)2SO4 can improve performance and stability of sulfidization. X-ray photoelectron spectroscopy indicates that after sulfidization, polysulfides and cuprous were appeared in malachite surface, infers that a redox reaction occurs between sulfur and copper on the surface of malachite. After addition of (NH4)2SO4, the percentage of polysulfides and cuprous were increased, it implies (NH4)2SO4 can accelerate the redox reaction. Computational results show that after adding (NH4)2SO4, the adsorption energy of HS- on the malachite surface is reduced, implies that (NH4)2SO4 can improve the stability of HS-adsorption on the surface of malachite.
3
Content available 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
Content available Effects of copper ions on malachite sulfidization flotation
Yin Wanzhong, Sheng Qiuyue, Ma Yingqiang, Sun Haoran, Yang Bin, Tang Yuan
Physicochemical Problems of Mineral Processing
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2020
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Vol. 56, iss. 2
300--312
EN
In this study, the effects of copper ions (Cu2+) on the sulfidization (Na2S) flotation of malachite was investigated using micro-flotation experiments, zeta-potential measurements, X-ray photoelectron spectroscopy (XPS) analysis, adsorption experiments, and Materials Studio simulation. The results indicated that the flotation recovery of malachite decreased after the pretreatment of the mineral particles with Cu2+ ions prior to the addition of Na2S. The results for zeta-potential measurements and XPS analysis revealed that less sulfide ion species in the pulp solution transferred onto the mineral surface, the sulfidization of malachite surface weakened. The adsorption amount of collector on the mineral surface decreased, and this finding was confirmed by the results of the zeta-potential and adsorption experiments. Materials Studio simulation revealed that the adsorption energy of HS- ions and C4H9OCSS- ions on malachite surface increased after the adding of Cu2+ ion. The competitive adsorption made Cu2+ ions depress sulfidization flotation of malachite, the dissolution of mineral surface affected the adsorption of reagents on it, and decreased the floatability of malachite.
5
Content available Effect of sulfidization on the stability of adsorption of isoamyl xanthate on malachite
Xiong Kun, Wen Shuming, Liu Zilong, Deng Jiushuai, Mao Yingbo
Physicochemical Problems of Mineral Processing
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2020
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Vol. 56, iss. 3
493--503
EN
The activity and stability of adsorbed isoamyl xanthate (IX) on a malachite surface before and after sulfidization were studied by calculating the malachite dissolved component and adsorption energy and performing experiments pertaining to the zeta potential, adsorption and desorption experiments, and flotation experiments. In the malachite slurry solution, the main components of copper are Cu2+, CuCO3, HCuO2-, CuO2-, and Cu(CO3)22-, and the concentration distribution of these components is related to the slurry pH value. Between pH 5 to 9, the main copper component in the slurry is CuCO3. The malachite surface is negatively charged; however, the sulfur ions or hydrosulfide ions can still adsorb on the surface at a pH of more than 8.2, which indicates that the sulfidization of malachite corresponds to the chemical adsorption, and the surface electrical properties of the malachite are not obvious to the sulfidization. The adsorption activity of malachite on IX is stronger than that of the sulfide malachite; however, the desorption ratio of IX with respect to the malachite is higher than that pertaining to the sulfide malachite. The adsorption energy of IX on the malachite and sulfide malachite surface was -449.6 kJ/mol and -1134.7 kJ/mol, respectively, and the IX adsorbed on the sulfide malachite surface was more stable. The flotation experiments indicated that the sulfidization of malachite reduced the consumption of IX; however, the recovery of malachite was improved.
6
Content available Dissolution kinetics of malachite in ethylene diamine phosphate solutions
Shen Peilun, Liu Ruizeng, Liu Dianwen, Zhan Xiaolin, Jia Xiaodong, Song Kaiwei
Physicochemical Problems of Mineral Processing
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2019
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Vol. 55, iss. 4
1039--1048
EN
Ethylene diamine phosphate (EDP), as a synthetic organic reagent, was used for the first time to leach malachite, and a new method of using organic amine to leach copper oxide ore was developed. The effects of stirring speed, particle size, reagent concentration, and reaction temperature on EDP-dissolution malachite were investigated. Results showed that malachite rapidly dissolved in EDP solution. The malachite-dissolving rate also increased with increased reagent concentration, increased reaction temperature, and decreased particle size. Stirring speed exhibited nearly no effect on EDP-induced malachite dissolution. The leaching kinetics was found to follow the shrinking-core model, and dissolution was controlled by surface chemical reaction with an activation energy of 52.63kJ×mol−1. A semiempirical rate equation was obtained to describe the dissolution process expressed as 1-(1-XCu)1/3=0.0149(CEDP)0.7814 × (Pmalachite)−0.7982×exp(−6.3308/T) ×t.
7
Content available Effect of ammonium sulfate on the sulfidation flotation of malachite
Liu C., Feng Q., Zhang G.
Archives of Mining Sciences
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2018
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Vol. 63, no. 1
139--148
EN
The effect of ammonium sulfate on the sulfidation flotation of malachite was investigated by micro-flotation tests, scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) measurements. Micro-flotation results show that the sodium sulfide concentration and strring time are difficult to control on the sulfidation flotation of malachite. However, when ammonium sulfate was used, the detrimental effect of mixing time and high dosage of sodium sulfide on the sulfidization flotation of malachite can be efficiently eliminated. SEM results showed that sulfidized film on malachite in the presence of ammonium sulfate, and EDS analysis results showed that more S element absorbed and distributed equality on the malachite surface, which was agreed well with the macro-flotation results.
PL
Badano wpływ siarczanu amonu na przebieg procesu siarczkowania w trakcie flotacji malachitu przy wykorzystaniu badania mikroskopowego, mikroskopii elektronowej skanningowej (SEM) oraz pomiarów spektrometrycznych rozpraszania energii EDS. Testy mikroskopowe wykazały, że stężenie siarczku sodu i długość czasu mieszania są parametrami, które niezwykle trudno kontrolować w trakcie procesu siarczkowania towarzyszącemu flotacji malachitu. Z kolei przy zastosowaniu siarczanu amonu, udaje się skutecznie wyeliminować niekorzystne efekty związane z czasem mieszania oraz wysokimi stężeniami siarczku sodu w trakcie flotacji malachitu poprzez siarczkowanie. Wyniki mikroskopii skaningowej wskazują, że przy zastosowaniu siarczanu amonu powstaje cienki film siarczkowy na malachicie zaś pomiary spektrometryczne wykazały większe ilości zaabsorbowanej i bardziej równomiernie rozłożonej siarki pierwiastkowej S na powierzchni malachitu, co pozostaje w pełnej zgodności z wynikami uzyskanymi z badania procesu flotacji w skali makro.
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