scholarly journals Leaching of polymetallic Cu-Zn-Pb concentrate with sodium nitrate in sulphuric acid

Tehnika ◽  
2021 ◽  
Vol 76 (4) ◽  
pp. 426-436
Author(s):  
Miroslav Sokić ◽  
Branislav Marković ◽  
Dušan Milojkov ◽  
Aleksandra Patarić ◽  
Mladen Bugarčić ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Sulphuric Acid ◽  
Sodium Nitrate ◽  
Atmospheric Pressure ◽  
Oxidizing Agent ◽  
Influence Of Temperature ◽  
Leaching Process ◽  
Gibbs Energies ◽  
Copper Zinc ◽  
Solid Residuals

The results of polymetallic sulphide Cu-Zn-Pb concentrate leaching with sulphuric acid in the presence of sodium nitrate as an oxidizing agent, at atmospheric pressure, are presented and discussed. Chemical composition and phase ratio of the starting concentrate and solid residuals after the leaching process are shown. Chemical reactions of leaching and their thermodynamic probabilities are predicted based on the calculated Gibbs energies and analysis of E-pH diagrams. The influence of temperature and time on the leaching degree of the concentrate's components is experimentally determined. It is shown that it is possible to obtain copper, zinc and iron in a solute form, while lead in the anglesite (PbSO4) form remains in the solid residual after the leaching process. The iron is being oxidized to Fe(III)-sulphate, which takes part in a sulphide leached minerals and turns into Fe(II)-sulphate.

scholarly journals Passivation of chalcopyrite during the leaching with sulphuric acid solution in presence of sodium nitrate

2010 ◽  
Vol 64 (4) ◽  
pp. 343-350 ◽  
Author(s):  
Miroslav Sokic ◽  
Vladislav Matkovic ◽  
Branislav Markovic ◽  
Nada Strbac ◽  
Dragana Zivkovic
Keyword(s):  
Acid Solution ◽  
Sulphuric Acid ◽  
Chemical Reactions ◽  
Sodium Nitrate ◽  
Sulphuric Acid Solution ◽  
Elemental Sulphur ◽  
Minor Amount ◽  
Leaching Process ◽  
Dta Analysis ◽  
A Minor

In this work, the process of the chalcopyrite leaching in sulphuric acid solution was investigated. Sodium nitrate was used as oxidant in the leaching process. Chemical reactions of leaching and their thermodynamic possibilities are predicted based on the calculated Gibbs energies and analysis of E?pH diagrams. The negative values of the Gibbs energy show that all chemical reactions are thermodynamically feasible at atmospheric pressure and in a temperature range 25-90?C. At high electrode potential and low pH values, Cu2+, Fe2+ and Fe3+ ions exist in water solutions. The increase of temperature reduces the probability of Fe3+ ion existence in the system. The chalcopyrite concentrate, enriched in the ?Rudnik? flotation plant, with 27.08% Cu, 25.12% Fe, 4.15% Zn and 2.28% Pb was used in the work. XRD and DTA analysis of the concentrate reveals that the sample contains mainly the chalcopyrite with small amount of sphalerite. For the description of the reaction of leaching process the leach residuals, obtained at different conditions, were chosen for XRD, TG/DTA and SEM/EDX analyses. The elemental sulphur and chalcopyrite phases identified in leach residuals confirm our prediction that the elemental sulphur is formed during the leaching process. Accordingly, elemental sulphur is the main product of the reaction, while a minor amount of sulphide sulphur is oxidized to sulphate during the leaching. The sulphur formed during the reaction was precipitated at the particle surfaces, and slowed down the leaching rate in the final stage of leaching process. In the initial stage, the reaction rate was controlled by the surface reaction. The mechanism, latter has been changed into a diffusion controlled one.

scholarly journals Surface modification of PMMA polymer and its composites with PC61BM fullerene derivative using an atmospheric pressure microwave argon plasma sheet

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Andrzej Sikora ◽  
Dariusz Czylkowski ◽  
Bartosz Hrycak ◽  
Magdalena Moczała-Dusanowska ◽  
Marcin Łapiński ◽  
...  
Keyword(s):  
Contact Angle ◽  
Surface Modification ◽  
Chemical Composition ◽  
Water Contact Angle ◽  
Plasma Sheet ◽  
Atmospheric Pressure ◽  
Argon Plasma ◽  
Fullerene Derivative ◽  
Water Contact ◽  
Pmma Polymer

AbstractThis paper presents the results of experimental investigations of the plasma surface modification of a poly(methyl methacrylate) (PMMA) polymer and PMMA composites with a [6,6]-phenyl-C61-butyric acid methyl ester fullerene derivative (PC61BM). An atmospheric pressure microwave (2.45 GHz) argon plasma sheet was used. The experimental parameters were: an argon (Ar) flow rate (up to 20 NL/min), microwave power (up to 530 W), number of plasma scans (up to 3) and, the kind of treated material. In order to assess the plasma effect, the possible changes in the wettability, roughness, chemical composition, and mechanical properties of the plasma-treated samples’ surfaces were evaluated by water contact angle goniometry (WCA), atomic force microscopy (AFM), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). The best result concerning the water contact angle reduction was from 83° to 29.7° for the PMMA material. The ageing studies of the PMMA plasma-modified surface showed long term (100 h) improved wettability. As a result of plasma treating, changes in the samples surface roughness parameters were observed, however their dependence on the number of plasma scans is irregular. The ATR-FTIR spectra of the PMMA plasma-treated surfaces showed only slight changes in comparison with the spectra of an untreated sample. The more significant differences were demonstrated by XPS measurements indicating the surface chemical composition changes after plasma treatment and revealing the oxygen to carbon ratio increase from 0.1 to 0.4.

Kinetic Study of the Diels-Alder Reaction of Cyclopentadiene with Bis(2-Ethylhexyl) Maleate

2013 ◽  
Vol 634-638 ◽  
pp. 541-545 ◽  
Author(s):  
Jun Seong Park ◽  
Dae Hee Yun ◽  
Tae Won Ko ◽  
Yong Sung Park ◽  
Je Wan Woo
Keyword(s):  
Kinetic Study ◽  
Reaction Temperature ◽  
Atmospheric Pressure ◽  
Arrhenius Equation ◽  
Alder Reaction ◽  
Diels Alder ◽  
Influence Of Temperature ◽  
Diels Alder Reaction ◽  
Influence Of Temperature On ◽  
Kinetics Of

The kinetics of the Diels-Alder reaction of cyclopentadiene with bis(2-ethylhexyl) maleate has been studied at temperatures between 25 and 100 °C and at atmospheric pressure. The influence of temperature on the kinetic constants was determined by fitting the results to the Arrhenius equation. As a result, fitting line similar with the linear curve of the Arrhenius equation at 25, 30 and 40 °C. However, the fitting curve, at 60, 80 and 100 °C, tended towards the outside of the curve in the form of Arrhenius equation. The ratio of endo/exo was a slight change from increase of the reaction temperature.

scholarly journals Effects of SO<sub>2</sub> oxidation on ambient aerosol growth in water and ethanol vapours

2005 ◽  
Vol 5 (3) ◽  
pp. 767-779 ◽  
Author(s):  
T. Petäjä ◽  
V.-M. Kerminen ◽  
K. Hämeri ◽  
P. Vaattovaara ◽  
J. Joutsensaari ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Sulphuric Acid ◽  
Cloud Condensation Nuclei ◽  
Aerosol Particles ◽  
The Arctic ◽  
Ambient Conditions ◽  
Similar Chemical ◽  
Ethanol Vapours ◽  
Hygroscopic Particles ◽  
Ultrafine Aerosol

Abstract. Hygroscopicity (i.e. water vapour affinity) of atmospheric aerosol particles is one of the key factors in defining their impacts on climate. Condensation of sulphuric acid onto less hygroscopic particles is expected to increase their hygrocopicity and hence their cloud condensation nuclei formation potential. In this study, differences in the hygroscopic and ethanol uptake properties of ultrafine aerosol particles in the Arctic air masses with a different exposure to anthropogenic sulfur pollution were examined. The main discovery was that Aitken mode particles having been exposed to polluted air were more hygroscopic and less soluble to ethanol than after transport in clean air. This aging process was attributed to sulphur dioxide oxidation and subsequent condensation during the transport of these particle to our measurement site. The hygroscopicity of nucleation mode aerosol particles, on the other hand, was approximately the same in all the cases, being indicative of a relatively similar chemical composition despite the differences in air mass transport routes. These particles had also been produced closer to the observation site typically 3–8 h prior to sampling. Apparently, these particles did not have an opportunity to accumulate sulphuric acid on their way to the site, but instead their chemical composition (hygroscopicity and ethanol solubility) resembled that of particles produced in the local or semi-regional ambient conditions.

scholarly journals COHERENT SYNCHRONIZATION OF PYRIDINE DIMERIZATION REACTIONS AND DECOMPOSITION OF “GREEN OXIDANTS” – H2O2 AND N2O

2021 ◽  
Vol 0 (4) ◽  
pp. 6-11
Author(s):  
I.T. Nagieva ◽  
◽  
N.I. Ali-zadeh ◽  
T.М. Nagiev ◽  
◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Nitrous Oxide ◽  
Gas Phase ◽  
Atmospheric Pressure ◽  
Raw Materials ◽  
Oxidizing Agent ◽  
Optimal Conditions ◽  
Pyridine Bases ◽  
Pharmaceutical Industries ◽  
Oxidation By Hydrogen Peroxide

In recent years, hydrogen peroxide and nitrous oxide (1) "green oxidants" – have attracted much attention of researchers as a selective oxidizing agent for the catalytic oxidation of pyridine bases. In this regard, the reaction of pyridine oxidation by hydrogen peroxide and nitrous oxide under homogeneous conditions, in the gas phase, without the use of catalysts, at atmospheric pressure, has been experimentally investigated. Areas of selective oxidation of pyridine with hydrogen peroxide and nitrous oxide have been established, and optimal conditions have been found for obtaining valuable raw materials required in the petrochemical, chemical, and pharmaceutical industries

Water Quality of Lake Iskanderkul and Its Tributaries

2020 ◽  
Vol 6 (2) ◽  
pp. 79-88
Author(s):  
Z.O. Normakhmedova ◽  
◽  
A.V. Mitusov
Keyword(s):  
Water Pollution ◽  
Water Quality ◽  
Chemical Composition ◽  
Fish Farming ◽  
Natural Phenomena ◽  
Change Dynamics ◽  
Chemical Composition Of Water ◽  
Study Results ◽  
Copper Zinc

This article presents the study results of the change dynamics in the chemical composition of water in Lake Iskanderkul and the rivers flowing into it, as well as the comparison of water quality in the water bodies of the Iskanderkul Basin and several mid-stream tributaries of the Zarafshan River. It was established that the chemical composition of water in Lake Iskanderkul and its tributaries meets the requirements of the corresponding state standard (GOST 2874-82 “Drinking Water”). However, in terms of dissolved oxygen, copper, zinc, lead and iron the water in Lake Iskanderkul does not satisfy fish farming requirements. The main water pollution sources in the area include such natural phenomena as floods, avalanches, mudslides, and rock dissolution.

Simple Fabrication of Superhydrophobic Surfaces Using Atmospheric-Pressure Plasma

2018 ◽  
Vol 941 ◽  
pp. 1808-1814 ◽  
Author(s):  
Elham Vazirinasab ◽  
Reza Jafari ◽  
Gelareh Momen ◽  
Tony Carreira
Keyword(s):  
Chemical Composition ◽  
Plasma Treatment ◽  
Silicone Rubber ◽  
Atmospheric Pressure ◽  
Chemical Characterization ◽  
Atmospheric Pressure Plasma ◽  
Processing Parameters ◽  
Superhydrophobic Surfaces ◽  
Pressure Plasma ◽  
Number Of Passes

Nature-inspired superhydrophobic surfaces have received immense industrial and academic interest due to their non-wettability and self-cleaning properties. To fabricate superhydrophobic silicone rubber surfaces, a simple, environmentally friendly atmospheric-pressure plasma treatment was applied. The effect of diverse plasma processing parameters on the final wettability behavior of the substrates, including plasma power, plasma frequency, number of passes, plasma jet speed, plasma cycle time and distance between the nuzzle outlet and substrate, were analyzed by means of design of experiments (DoE). Surface chemical characterization illustrated the influence of plasma treatment on the chemical composition of the produced silicone rubber. Furthermore, the presence of microstructures as well as the chemical composition of the surface was confirmed using scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy analysis.

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