Temat: copper activation - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Copper adsorption reaction rate and ion exchange ratio during the copper activation of sphalerite
Autorzy:: Liu, J.
Luo, D.
Huang, L.
Wang, Y.
Wen, S.
Tematy:: sphalerite
copper activation
solution chemistry
ion exchange ratio
reaction rate; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/110651.pdf Link otwiera się w nowym oknie
Opis:: A theoretical analysis method of the solution chemistry characteristic of Cu(II) at various pH values was developed. Using such method, the existence form of Cu species and their proportions in aqueous solution can be clearly determined. After that, the copper adsorption and ion exchange ratio (E) during the copper activation of sphalerite were investigated. The results indicated that the copper activation of sphalerite can be divided into two stages, i.e., the fast activation stage (t ≤4 min) and slow activation stage (t >4 min). The general form of the copper adsorption rate was determined as ΓCu=K1ln(t) +Γ1, which is confirmed by the data fitting of the fast activation stage. The lower activation pH results in higher ion exchange efficiency for Cu substituting Zn. For a strong acid pH of 4.1, the E maintains about 1:1 in the entire activation time range and is not dependent on the activation time. However, the value of E is greater than 1 under weak acidic (pH=6.2) and alkaline (pH=9.1) pH conditions and it significantly depends on the activation time. For such conditions, E decreases with increase in the activation time, which supports the ion exchange mechanism, but within short activation time, it is not a 1:1 ion exchange process.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 2.

Tytuł:: The mechanism of azide activation of polyphenol oxidase II from tobacco.
Autorzy:: Shi, Chunhua
Liu, Qingliang
Dai, Ya
Xie, Yongshu
Xu, Xiaolong
Tematy:: polyphenol oxidase (PPO)
azide activation
peroxide activation
superoxide activation
copper proteins; Pokaż więcej
Wydawca:: Polskie Towarzystwo Biochemiczne
Powiązania:: https://bibliotekanauki.pl/articles/1043711.pdf Link otwiera się w nowym oknie
Opis:: So far, azide has been consistently reported to act as an inhibitor of metal enzymes, especially copper proteins. The present work shows that azide can also act as an activator of polyphenol oxidase II (PPO II) from tobacco leaves. From0 the square-wave voltammetry of native PPO II, peroxide-PPO II complex and azide-PPO II complex, the reduction of nitro blue tetrazolium by the enzymes and activation of PPO II by peroxide it follows that the binding of azide to PPO II induces the formation of CuO(2)(2-)Cu in the active site of PPO II from CuO(2)(-)Cu in native PPO II. The reason for azide acting as an activator can be attributed to azide complexing with PPO II, thus inducing the formation of CuO(2)(2-)Cu, which is the active site of the peroxide-PPO II complex in which peroxide plays the role of activator.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 3.

Tytuł:: Study of flotation behavior and mechanism of cervantite activation by copper ions
Autorzy:: Wang, J.
Wang, Y.
Fu, K.
Xu, L.
Wang, Z.
Sun, H.
Xiao, J.
Tematy:: flotation
cervantite
copper ions
activation mechanism; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/110228.pdf Link otwiera się w nowym oknie
Opis:: Copper-ion activation plays a highly important role in cervantite (Sb2O4) flotation. Without metal-ion activation, cervantite cannot be floated by sodium oleate. In this study, flotation tests were conducted to study the effect of Cu2+ on the flotation behaviours of cervantite and quartz (SiO2) as the main gangue mineral. Metal-ion adsorption capacities, zeta potentials, solution chemistry and X-ray photoelectron spectra were analyzed to study the adsorption behavior and mechanism of copper ions and sodium oleate interaction with the minerals surfaces. The results demonstrate that under weakly acidic conditions, cervantite can be flotated and separated from quartz by the addition of copper ions. The reason is that copper ions can be selectively adsorbed on the cervantite surface under weakly acidic conditions, thereby promoting the adsorption of sodium oleate onto the cervantite surface by chemical adsorption. Conversely, copper ions are weakly adsorbed on quartz surfaces below pH 6.1, and sodium oleate cannot be adsorbed on quartz surfaces by chemical adsorption. The hydroxy copper species are integral to the selective activation of cervantite over quartz.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 4.

Tytuł:: Inhibiting effect of citric acid on the floatability of serpentine activated by Cu(II) and Ni(II) ions
Autorzy:: Huang, Jun-wei
Zhang, Cheng-qiang
Tematy:: copper ion
nickel ion
serpentine
floatation
activation
inhibiting; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/110224.pdf Link otwiera się w nowym oknie
Opis:: The laboratory researches about the inhibiting effect of citric acid on the flotation performance of serpentine activated by Cu²⁺ and Ni²⁺ were carried out through micro flotation tests, zeta potential measurements, collector adsorption capacity measurements and solution chemistry analysis. The flotation results showed that Cu²⁺ and Ni²⁺ could remarkably activate the flotation of serpentine when the pH value was more than 6, however, this activation could be effectively weakened by adding citric acid. Zeta potential measurement and adsorption capacity measurement indicated that the presence of citric acid could prevent the adsorption of Cu²⁺ and Ni²⁺, and therefore reduce the adsorption amount of potassium butyl xanthate on serpentine surface. Furthermore, solution chemical analysis of the flotation system showed that copper hydroxide Cu(OH)_2(s) and the nickel hydroxide Ni(OH)2(s) were the main component in the pH range of 9 to 10, which adsorbed onto serpentine surface and made it activated; while the citric acid could effectively prohibit the formation of these metal hydroxide in slurry so as to inhibit the activation impact.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 5.

Tytuł:: A metallosupramolecular octahedron assembled from twelve copper(I) metal ions and six 4,4 -(1,2-phenylene)bis(3,5-dimethylpyrazol-1-ide) ligands
Autorzy:: Grzywa, Maciej
Bredenkötter, Björn
Spirkl, Sebastian
Volkmer, Dirk
Denysenko, Dmytro
Nitek, Wojciech
Opis:: The novel coordination compound [CuI12(C16H16N4)6]·8DMAc, (2), (DMAc = N, N-dimethylacetamide) was prepared in solvothermal or microwave assisted reaction. It contains four metallamacrocyclic trinuclear copper(I) pyrazolate coordination units, which occupy four (opposite) faces of an imaginary metallosupramolecular octahedron. Six (4,4′-(1,2-phenylene)bis(3,5-dimethylpyrazol-1-ide) ligands (L12–) are placed at the corners of the octahedron. Crystals of the free ligand H2L1 [1,2-bis(3,5-dimethyl-1H-pyrazol-4-yl)benzene, (1)], and [CuI12(C16H16N4)6]·8DMAc (2), were characterized by single-crystal X-ray structure analyses. Lingand 1 crystallizes in the monoclinic crystal system, with: a = 9.0118(9), b = 14.0075(11), c = 11.7484(11) Å, β = 104.945(5)°, V = 1432.9(2) Å3, space group P21/c (no. 14). Compound 2 crystallizes in the tetragonal system, with: a = b = 19.506(5), c = 42.888(5) Å, V = 16318(6) Å3, space group I41/amd (no. 141). Compound 2 represents a porous structure, where each metallosupramolecular octahedron encloses a solvent-filled cavity of 889 Å3 (accounting for 6 DMAc molecules, 21.8 % of the cell volume). The incomplete crystal packing arrangement of adjacent [CuI12(C16H16N4)6] moieties in addition leads to solvent-filled interstitial voids accounting to 8.1 % of the cell volume. Removing solvent molecules in vacuo is accompanied by reversible structural changes, leading to a partial loss of porosity, as revealed by Ar-BET sorption analysis. Compounds 1 and 2 were further characterized by elemental and thermogravimetric analysis, X-ray powder diffraction, FTIR-, UV/Vis- and fluorescence spectroscopy. Preliminary results on the activation of molecular oxygen by compound 2 are presented.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

Artykuł

na półce

Skocz do pozycji: 6.

Tytuł:: Study of process water effect on the activation of sphalerite during differential flotation of Pb-Cu-Zn
Autorzy:: Gutiérrez Pérez, Victor Hugo
Olvera Vázquez, Seydy Lizbeth
Santos Madrid, Rocio
Regino Piña, Rafael
Cruz Ramírez, Alejandro
Rivera Salinas, Jorge Enrique
Alaniz Hernández, Daniel Israel
Tematy:: sphalerite activation
process water
differential flotation
copper ions
lead ions; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/2146897.pdf Link otwiera się w nowym oknie
Opis:: This work was aimed to analyze the effect of concentration of Cu.2+ and Pb.2+ ions in flotation process water with sphalerite activation, the analysis was performed at Cozamin Mining flotation circuit. This analysis demonstrated that (i) it was possible to determine the relationship between Sodium Cyanide and Ammonium Bisulfite used as depressants and Cu.2+ and Pb.2+ contents in the process water. (ii) It also proved the relationship between lead and iron content in the head with the Pb.2+ ions in process water. According to the data gathered and analysis performed, (iii) it was also determined that it was possible to reuse process water as long as the use of Ammonium Bisulfite was reduced and recommended replacing the use of Sodium Cyanide with Zinc Sulfate (ZnSO4) as a depressant of Sphalerite. Additionally, the concentration of Cu.2+ and Pb.2+ ions in the water should be controlled in a range of 10 to 20 ppm and 0.10 to 0.20 ppm, respectively.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 7.

Tytuł:: DFT quantum chemical modeling of the interaction of alkenes with $Cu^{+}$ sites in zeolites
Autorzy:: Brocławik, Ewa
Datka, Jerzy
Kozyra, Paweł
Rejmak, Paweł
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

Artykuł

na półce

Skocz do pozycji: 8.

Tytuł:: Uptake of copper ion using protonated dry alginate beads from dilute aqueous solutions
Autorzy:: Aracena, Alvaro
Álvarez, César
Jerez, Oscar
Guajardo, Nadia
Tematy:: removal mechanism
copper ions
alginate beads
pseudo-first order kinetics model
activation energy; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/109473.pdf Link otwiera się w nowym oknie
Opis:: This research aimed to identify the copper ion removal mechanism when using protonated dry alginate beads. This mechanism was explained through ion exchange between Cu ions and the protons from the functional groups of the alginate beads. Copper removal increased with stirring velocity, reaching values of 97.5 mg g-1 (97.5×10-3 kg/kg of PDAB) of dry alginate at 200 rev min-1, at a solution pH of 6.0 and a run time of 360 min. For the lowest level of copper concentrations, at 10 mg dm-3 (10×10-6 kg dm-3), full removal was attained. The removal kinetics was represented by a pseudo- first order model. A value of 0.0131 min-1 was found for the velocity constant. Under equilibrium conditions, the experiment data was fit to the Langmuir adsorption model, and the highest removal values were 270.3, 222.2 (222.2×10-3 kg/kg of PDAB) and 49 mg g-1 (49×10-3 kg/kg of PDAB) for pH values of 5.0, 3.5 and 2.5, respectively. These are higher than most sorbents used in the literature for copper removal. Increased temperature leads to higher Cu removal. The activation energy was calculated at 9.3 kJ mol-1 for the temperature range of 283 to 343K. Observations using SEM and composition measurements of the alginate cross-section taken by EDS showed a uniform distribution of the copper concentration through the structure of the alginate beads, independent of the solution pH, contact time and temperature.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 9.

Tytuł:: Study of Hot Deformation Behavior of CuFe2 Alloy
Autorzy:: Schindler, I.
Sauer, M.
Kawulok, P.
Rodak, K.
Hadasik, E.
Jabłońska, M. Barbara
Rusz, S.
Ševčák, V.
Tematy:: copper alloy CuFe2
hot ductility
stress-strain curves
hot deformation activation energy; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/353206.pdf Link otwiera się w nowym oknie
Opis:: Nil strength temperature of 1062°C and nil ductility temperature of 1040°C were experimentally set for CuFe2 alloy. The highest formability at approx. 1020°C is unusable due to massive grain coarsening. The local minimum of ductility around the temperature 910°C is probably due to minor formation of γ-iron. In the forming temperatures interval 650-950°C and strain rate 0.1-10 s^-1 the flow stress curves were obtained and after their analysis hot deformation activation energy of 380 kJ·mol^-1 was achieved. Peak stress and corresponding peak strain values were mathematically described with good accuracy by equations depending on Zener-Hollomon parameter.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 10.

Tytuł:: Spoiwo bezklinkierowe otrzymane w wyniku alkalicznej aktywacji zeszklonego żużla pomiedziowego
Non-clinker binder obtained by alkali-activation of vitrified copper slag
Autorzy:: Kuterasińska, J.
Król, A.
Tematy:: żużel pomiedziowy
aktywacja alkaliczna
spoiwa żużlowo-alkaliczne
szkło wodne
copper slag
alkali activation
alkali activated binders
water glass; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Ceramiki i Materiałów Budowlanych
Powiązania:: https://bibliotekanauki.pl/articles/168581.pdf Link otwiera się w nowym oknie
Opis:: W artykule przedstawiono wyniki badań dotyczące nowego rodzaju spoiwa bezklinkierowego powstałego w wyniku aktywacji alkalicznej granulowanego żużla pomiedziowego. Ważnym elementem przeprowadzonych badań było określenie wpływu standardowych i przyspieszonych warunków dojrzewania na właściwości mechaniczne otrzymanych kompozytów.
The article presents the results of research on a new type of non-clinker binder obtained as a result of alkaline activation of a granular copper slag. An important element of the study was determination of the maturation conditions effect (standard or accelerated) on the mechanical properties of the composites.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Informacja

Wyszukujesz frazę "copper activation" wg kryterium: Temat