Temat: sulfidization - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Influence of hydrated Ca2+ and Mg2+ complexes on the sulfidization of smithsonite : density functional based tight binding (DFTB+) study
Autorzy:: Wu, Zhiqiang
Tang, Xiaoqin
Chen, Jianhua
Chen, Ye
Tematy:: smithsonite
sulfidization
DFTB+ hydrated
adsorption; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/2175440.pdf Link otwiera się w nowym oknie
Opis:: Ca2+ and Mg2+ are the most dominating unavoidable ions in the smithsonite flotation. In this paper, the effect of Ca2+ (Mg2+) on the surface of smithsonite sulfidization in a system where water molecules are present was investigated using density functional based tight binding (DFTB+) simulations for the first time. The results indicated that the adsorption of hydrated Ca2+ complexes is stronger than that of hydrated Mg2+ complexes on the hydrated smithsonite (101) surface. In addition, at low concentrations of sodium sulfide, there is no adsorption of HS- on the surface pre-adsorbed with hydrated Ca2+ complexes, but only on the surface pre-adsorbed with hydrated Mg2+ complexes. At high concentrations of Na2S, S2- weakens the adsorption of hydrated Ca2+ complexes due to competitive adsorption, but the presence of S2- could desorb hydrated Mg2+ complexes from the surface. The results compared the differences in effects of Ca2+ and Mg2+ on smithsonite sulfidization, which could provide an atomic scale basis for researching the surface sulfidization of oxide minerals.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: New insights into the promotion mechanism of $(NH_4)_2SO_4$ in sulfidization flotation: a combined experimental and computational study
Autorzy:: Chen, Daixiong
Liu, Mengfei
Hu, Bo
Dong, Yanhong
Xue, Wei
He, Peng
Chen, Fang
Zhu, Jianyu
Zhang, Chenyang
Tematy:: malachite
promotion
sulfidization
flotation
mechanism; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/1446762.pdf Link otwiera się w nowym oknie
Opis:: 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 $(NH_4)_2SO_4$. 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 $Na_2S•9H_2O$ changes the surface properties of malachite and provide the conditions for adsorption of butyl xanthate (BX). After promoting the sulfidization by $(NH_4)_2SO_4$, BX is more effective in improving the hydrophobicity. SEM-EDS and AFM results show that $(NH_4)_2SO_4$ 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 $(NH_4)_2SO_4$, the percentage of polysulfides and cuprous were increased, it implies $(NH_4)_2SO_4$ can accelerate the redox reaction. Computational results show that after adding $(NH_4)_2SO_4$, the adsorption energy of HS- on the malachite surface is reduced, implies that $(NH_4)_2SO_4$ can improve the stability of HS-adsorption on the surface of malachite.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Effects of copper ions on malachite sulfidization flotation
Autorzy:: Yin, Wanzhong
Sheng, Qiuyue
Ma, Yingqiang
Sun, Haoran
Yang, Bin
Tang, Yuan
Tematy:: malachite
sulfidization flotation
Cu2+ ion
depression; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/110331.pdf Link otwiera się w nowym oknie
Opis:: 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.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Efficient sulfidization of lead oxide at high temperature using pyrite as vulcanizing reagent
Autorzy:: Zheng, Y.-X.
Lv, J.-F.
Wang, H.
Wen, S.-M.
Huang, L.
Tematy:: lead oxide
sulfidization roasting
pyrite
reaction mechanism
TG; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/110351.pdf Link otwiera się w nowym oknie
Opis:: A sulfidization roasting-flotation process was usually viewed to be effective in treating the refractory oxide ore. In this paper, pyrite was proposed to be applied as a potential vulcanizing reagent to transform PbO or its surface to PbS based on feasibilities of technology and economy. The evolution process, phase and characteristics of crystal growth were investigated by TG, XRD and SEM-EDS, respectively, to interpret the interaction mechanism of lead oxide and pyrite at high temperature. It was found that the decomposition process of pyrite under argon atmosphere was a slow process of sulfur released from FeS2 to FexS, which made the process easier to be controlled. When PbO was introduced into the system, the initial solid-solid (PbO-FeS2) reaction and prevailing solid-gas (PbO-S2(g)) reaction occurred at about 500 °C and 700 °C, respectively. Combined with the SEM-EDS analyses results, the optimal temperature for the sulfidization of PbO should be in the range of 700-750 °C.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Effect of pH on surface characteristics and flotation of sulfidized cerussite
Autorzy:: Feng, Q.
Wen, S.
Zhao, W.
Liu, J.
Liu, D.
Tematy:: cerussite
sulfidization
excessive sulfide ions
pH
surface analysis; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/110234.pdf Link otwiera się w nowym oknie
Opis:: The effect of pH on surface characteristic and flotation of sulfidized cerussite was studied by micro-flotation tests, dissolution experiments, scanning electron microscopy (SEM) energy dispersive spectrometer (EDS), and X-ray photoelectron spectroscopy (XPS). The micro-flotation tests demonstrated that higher recovery of cerussite was achieved in acidic solutions than that in alkaline solutions. Despite the addition of high collector concentrations, cerussite flotation did not improved in alkaline solutions. The dissolution performance of sulfide-treated cerussite at different pH values indicated that the lead sulfide layer on the surface of sulfide-treated cerussite could exist in acidic solutions and it was more stable at acidic pH than in alkaline solutions. This finding was proved by the SEM-EDS and XPS analyses.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Lead species formation on pure hemimorphite surface and its performance for subsequent sulfidization
Autorzy:: Liang, Guanyu
Zhang, Song
Xian, Yongjun
Chen, Luzheng
Tematy:: hemimorphite
lead ions adsorption
hydroxy lead
sulfidization
xanthate flotation; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/58971291.pdf Link otwiera się w nowym oknie
Opis:: Hemimorphite is important-supplementary resource for the commercial zinc production, but it easy loses into tailings due to extreme difficulty for its surface sulfidization. Adding active metal ions after sulfidization have been widely proposed for enhancing hemimorphite floatability, but its desired efficiency in flotation practice has not yet been completely achieved caused by the instability of sulfide layer. Whereas pre-adsorption of active metal ions to modify the hemimorphite surface has strong potential to make up for this shortcoming. Herein, the feasibility and appropriate environment of free Pb2+ for modifying the pure hemimorphite surface was evaluated. Subsequently, the performance of Pb2+ adsorption for enhancing sulfidization stability and floatability of hemimorphite were investigated. The X-ray photoelectron spectroscopy results indicated that the Pb2+ adsorption on hemimorphite surface was achieved through the Pb ions displacement for Zn ions, and it was bond to oxygen-containing groups on hemimorphite surface. Such adsorption was strengthened with the increasing of solution pH, owing to the abundant Pb hydroxyl species precipitated on mineral under alkaline conditions, in term of the results of visual MINTEQ modeling and time-of-flight secondary-ion mass spectrometry. In addition, the X-ray photoelectron spectroscopy results showed dominant Pb hydroxyl species further reacted with sulfur during subsequent sulfidization to generate much more S species than that of without Pb2+ pre-modification. Meanwhile, such sulfide layer composed by Pb2+ on the mineral surface presented much higher stability than Zn-S species, which was verified via adsorption and desorption tests. As a result, the sulfidization and flotation recovery of hemimorphite increased after Pb2+ pre-adsorption.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Effect of ammonium sulfate on the sulfidation flotation of malachite
Wpływ obecności siarczanu amonu na przebieg procesu sulfitacji (siarczkowania) w trakcie flotacji malachitu
Autorzy:: Liu, C.
Feng, Q.
Zhang, G.
Tematy:: malachit
siarczek amonu
flotacja poprzez sulfidację (siarczkowanie)
budowa powierzchniowa
malachite
ammonium sulfate
sulfidization-flotation
surface morphology; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/220224.pdf Link otwiera się w nowym oknie
Opis:: 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.
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.
Dostawca treści:: Biblioteka Nauki

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