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1

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

Enhancing flotation of smithsonite by using 1,3,5-Triazinane-2,4,6-trithione as sulfidation

He Kunzhong, Zhou Hepeng, Zhang Yongbing, Tang Xuekun, Luo Xianping, Han Haisheng

Physicochemical Problems of Mineral Processing

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2021

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Vol. 57, iss. 5

1--14

EN

1,3,5-Triazinane-2,4,6-trithione (TMT) was used for the first time as a sulfidation agent in the flotation of smithsonite. Results showed that 80.5% recovery rate could be obtained in the presence of TMT (5 × 10-5 mol/L) and butyl xanthate (5 × 10-4 mol/L). However, the recovery rate was only 59.4% when sodium sulfide (5 × 10-5 mol/L) was used. Micro-flotation test and contact angle measurement showed that TMT activation was better than sodium sulfide activation. Besides, the contact angle increased from 32.44° (untreated) to 89.58° (treated with TMT), which was significantly higher than 50.2° (treated with sodium sulfide). Fourier Transform Infrared spectroscopy(FT-IR) and Zeta potential test showed the chemisorption of TMT on the smithsonite surface. The results of ICP spectral detection and solution chemistry calculation revealed that Zn3TMT complex precipitates in the smithsonite pulp were formed on the mineral surface at pH 6.5. A hydrophobic film was also formed on the mineral surface after TMT treatment, and more adsorption sites were provided for butyl xanthate. Thus, the adsorption of collector was significantly enhanced.

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

Odporność wybranych powłok ochronnych na korozję płomieniową w kotłach pyłowych niskoemisyjnych

Ćwiek J., Łabanowski J., Sozańska M., Topolska S.

Rynek Energii

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2013

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Nr 2

61--64

PL

W artykule omówiono zagadnienie odporności powłok na rurach ekranowych kotłów niskoemisyjnych na korozję płomieniową. Przedstawiono wyniki badań diagnostycznych powłok ochronnych na rurach ekranowych kotłów pyłowych, niskoemisyjnych, pracujących przy współspalaniu biomasy. Badano powłoki natryskiwane cieplnie Al2O3/Ni-30Cr oraz hybrydowe nanoszone techniką malarską. Stan powłok oceniono po jednym i dwóch latach eksploatacji w warunkach oddziaływania płomienia i spalin, oraz erozyjnego oddziaływania strumienia powietrza ze zdmuchiwacza. Stwierdzono, że badane powłoki ochronne nie zabezpieczają powierzchni rur ekranowych przed korozją płomieniową, w tym siarkową, w warunkach spalania podstechiometrycznego. Współspalanie biomasy znacząco przyśpiesza degradację powłok, szczególnie hybrydowych nanoszonych techniką malarską. Trwałość powłok wynosiła do dwóch lat eksploatacji kotła.

EN

Diagnostic research on durability of protection coatings on water-wall tubes in low-emission boilers has been presented in the paper. Thermal spraying Al2O3/Ni-30Cr and hybrid paint coatings were evaluated. Durability of the coatings was evaluated after one and two years of service in direct action of flame, flue gas, and air flux from blower. It has been said that the coatings do not protect heating surface of water-wall tubes from hot corrosion, including sulfidation under substoichiometric burning. Durability of the coatings is two years of exploitation of a boiler.

5

The surface layer degradation of γ-TiAl phase based alloy

Małecka J.

Journal of Achievements in Materials and Manufacturing Engineering

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2013

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Vol. 58, nr 1

31--37

EN

Purpose: The aim of the present research is to describe the chemical composition and microstructure of the surface layer of Ti-46Al-7Nb-0.7Cr-0,1Si-0.2Ni alloy after the test of isothermal oxidation in 9%O2+0.2%HCl+0.08%SO2+N2 during 250 h. Design/methodology/approach: The objectives were achieved using several techniques including conventional metallography, SEM, BSE, EDX. The oxides scales and their effects were investigated at temperatures 750ºC. Findings: This investigation confirms that the better protection of the substrate was determined using AlCrN coating. Research limitations/implications: The basic limitations concern alloys in a higher temperature and establish the oxidation kinetics of the analysed alloy as a function of time and temperature. Practical implications: One of practical outcomes is to select the coatings which guarantee the reduction of oxidation behavior. It is recommended to use alloys with AlCrN coating. Originality/value: Original value of the paper is assessing of the oxidation resistance of Ti-46Al-7Nb-0.7Cr-0.1Si–0.2Ni-based intermetallic alloy at the conditions combining high temperature and sulphur and chlorine compounds-containing atmosphere. The novelty of this research deals with the mechanism of oxidation at such boundary conditions. This knowledge can support the design of parts made of the intermetallic alloy. The problem considered is currently important for aeroplane and automotive industry, especially for gas turbine manufacturers.

6

Ocena trwałości powłok ochronnych na rurach ekranowych kotłów niskoemisyjnych

Ćwiek J.

Ochrona przed Korozją

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2012

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nr 4

172-175

PL

W artykule przedstawiono wyniki badań diagnostycznych powłok ochronnych pracujących na rurach ekranowych w kotłach pyłowych niskoemisyjnych. Badano powłoki natryskiwane cieplnie Al2O3/Ni-30Cr oraz hybrydowe nanoszone techniką malarską. Oceniono trwałość powłok po jednym i dwóch latach eksploatacji w warunkach bezpośredniego oddziaływania płomienia i spalin, oraz erozyjnego oddziaływania strumienia powietrza ze zdmuchiwacza. Stwierdzono, że badane powłoki ochronne nie zabezpieczają powierzchni ogrzewanej rur ekranowych przed korozją płomieniową, w tym siarkową, w warunkach spalania podstechiometrycznego. Trwałość powłok wynosi od jednego do dwóch lat eksploatacji kotła.

EN

Diagnostic research on durability of protection coatings on water-wall tubes in low-emission boilers has been presented in the paper. Thermal spraying Al2O3/Ni-30Cr and hybrid paint coatings were evaluated. Durability of the coatings was evaluated after one and two years of service in direct action of fl ame, fl ue gas, and air flux from blower. It has been said that the coatings do not protect heating surface of waterwall tubes from hot corrosion, including sulfi dation under substoichiometric burning. Durability of the coatings is from one to two years of exploitation of a boiler only.

7

Badania zachowania się stali Crofer 22APU w atmosferze H2/H2S

Żurek Z., Jaroń A.

Ochrona przed Korozją

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2010

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nr 4-5

246-249

PL

W pracy przedstawiono badania siarkowania stali Crofer 22APU przeznaczonej do budowy interkonektorów w ogniwach typu SOFC. Badania prowadzono na próbkach wstępnie utlenianych i nieutlenianych w atmosferze powietrza. Siarkowanie prowadzono w zakresie temperatur pracy ogniwa paliwowego (600-900oC) w atmosferach o różnym ciśnieniu parcjalnym siarki - pS2 od 10-7 do 10-1 Pa. Stwierdzono, że proces siarkowania przebiega zgodnie z prawem wykładniczym o zmiennym wykładniku "n". Przeprowadzono badania kinetyki siarkowania oraz fizykochemiczne badania utworzonej zgorzeliny z wykorzystaniem metod XRD, EDX i SEM. Przeprowadzone analizy wykazały, że głównym składnikiem wytworzonej zgorzeliny były siarczki żelaza i chromu, a przy niższych ciśnieniach parcjalnych siarki w zgorzelinie występowały jedynie siarczki chromu.

EN

In this paper authors present results of sulfidation of Crofer steel in H2/H2S. The high temperature corrosion behavior of Crofer 22APU and preoxidized Crofer steel were studied in the temperatures range 600-900oC in H2/H2S atmospheres. Sulphur partial pressures (pS2) was in the range 10-7 to 10-1 Pa. The kinetics show that the sulfidation process of preoxidized samples was going slower. Morphology of the scales (surface and cross section) have been observed by SEM. Phase and chemical composition have been studied by EDX and XRD methods. It was found that scale formed on Crofer steel was built with porous sulphides and in some case (pS2, temperature) the internal sulfidation of steel was observed. The phase analysis of the scale reveled that it is composed mainly of a sulphides of iron and chromium but in low sulfur partial pressure only chromium sulfide was detected.

8

High temperature corrosion of Ti-46Al-7Nb-0.7Cr-0.1Si-0.2Ni intermetalics–based alloys in N2-O2-SO2 environments

Małecka J., Grzesik W.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 43, nr 1

252-259

EN

Purpose: The reason for this research is to test the intermetalic alloy with improved oxidation and sulfidation resistance to air and a N2-O2-SO2 gas mixture at temperatures higher than 900 şC, typical for working conditions of highly loaded parts of gas turbine. Design/methodology/approach: The objectives were achieved using several techniques including conventional metallography, SEM, BSE, EDX and precision measurements of mass loss. The oxides scales and their effects were investigated and compared for two test temperatures, i.e. 900 şC and 950 şC. Findings: This investigation confirms that oxidation in 9%O2+0.3%SO2+N2 atmosphere causes an increase in the rate of oxidation in comparison to the pure oxidation in air. The main conclusion is that combined oxidation and sulfidation at temperature between 900 şC and 950 şC results in the formation of specific phases at the product-substrate and product-oxide boundaries. Research limitations/implications: The basic limitations concern alloys with different chemical composition, especially with different percentage of niobium (between 4-10 at %), not only with 7 at % as in the present investigation. Also, atmosphere with higher content of SO2 should be tested. Another problem is to optimize the surface integrity including surface roughness and sublayer properties. Practical implications: One of practical outcomes is to select the thermal conditions and surface preparation technology which guarantee the reduction of oxidation in 9%O2+0.3%SO2+N2 atmosphere. It is recommended to use alloys with higher content of niobium. Originality/value: Original value of the paper is assessing of the oxidation resistance of Ti–46Al–7Nb–0.7Cr–0.1Si–0.2Ni-based intermetallic alloy at the conditions combining high temperature and sulphur-containing atmosphere. The novelty of this research deals with the mechanism of oxidation at such boundary conditions and its quantification. This knowledge can support the design of parts made of the intermetalic alloy. The problem considered is currently important for aeroplane and automotive industry, especially for gas turbine manufacturers.

9

Wpływ siarkowania na przeżywalność i aktywność fermentacyjną kriofilnych drożdży winiarskich

Kusewicz D., Rokiciniak E.

Zeszyty Naukowe. Chemia Spożywcza i Biotechnologia / Politechnika Łódzka

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1999

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Z. 61

37-47

PL

Kriofilne drożdże winiarskie wykazały zróżnicowaną oporność na siarkowanie. W obu podłożach mineralnym i moszczu jabłkowym dynamika wzrostu drożdży, żywotność, aktywność fermentacja zależała od stężenie SO2, temperatury hodowli, pH i ras drożdży. Znaczne obniżenie przeżywalności drożdży ( 30 ÷ 75% ) i aktywności fermentacyjnej (60 ÷ 69% ) było obserwowane przy zawartości 100 mgSO2/l w podłożu. Najbardziej odporny na działanie SO2 był sulfitowy szczep Jonannisberg, a najbardziej wrażliwa rasa Johannisberg-Riesling.

EN

The cryophilic wine yeast showed varied resistance to sulphuration. In both media mineral and apple must the dynamics of yeast growth, survival, fermentation activity depended on the SO2 concentration, cultivation temperature, pH and the yeast races. The notable decrease of yeasts viability ( 30 ÷ 75% ) and fermentation activity ( 60 ÷ 69% ) was observed at the level of 100 mg SO2/1 of the fermentation medium. The most resistance to action of SO2 was sulphured Johannisberg strain and the most sensitive Johannisberg-Riesling race.