Reaction mechanism and kinetics of sulfide copper concentrate oxidation at elevated temperatures

Sulfide copper concentrate from domestic ore deposit (Bor, Serbia) was subjected to oxidation in the air atmosphere due to a better understanding of reaction mechanism and oxidation of various sulfides present in the copper concentrate at elevated temperatures. Results of the initial sample characterization showed that concentrate is chalcopyrite–enargite-tennantite type, with an increased arsenic content. Characterization of the oxidation products showed the presence of sulfates, oxysulfates, and oxides. Based on predominance area diagrams for Me-S-O systems (Me = Cu, Fe, As) combined with thermal analysis results, the reaction mechanism of the oxidation process was proposed. The reactions which occur in the temperature range 25 – 1000 °C indicate that sulfides are unstable in the oxidative conditions. Sulfides from the initial sample decomposed into binary copper and iron sulfides and volatile arsenic oxides at lower temperatures. Further heating led to oxidation of sulfides into iron oxides and copper sulfates and oxysulfates. At higher temperatures sulfates and oxysulfates decomposed into oxides. Kinetic analysis of the oxidation process was done using Ozawa’s method in the non-isothermal conditions. The values for activation energies showed that the reactions are chemically controlled and the temperature is the most influential parameter on the reaction rates

The influence of novel organic gold complex on photoresist layers of printed circuit boards

The goal of this paper was to study the influence of organic gold complex based on mercaptotriazole on photoresist layers used in manufacturing of printed circuit boards (PCBs). Investigations were performed by immersion the previously prepared boards in electrolytes with different pH values (pH=2, 4, 7, 9 and 12) at gold concentration of 2.5 g/dm3 and in gold complexes with different gold concentrations (1.5; 2.0; 2.5; 3.0 and 3.5 g/dm3) at pH value of pH=9. Investigations showed that photoresist layers on boards are the most resistant at optimal operating conditions, pH=9 and concentration of gold of 2.5 g/dm3

Formulation and characterization of electrolyte for decorative gold plating based on mercaptotriazole

AbstractA procedure for the formulation and characterization of a gilding electrolyte based on mercaptotriazole is described. It was found that the electrolyte can be synthesized in a wide pH range, so solutions with different pH values (2, 4, 7, 9 and 12) have been prepared and analyzed. Inductively coupled plasma atomic emission spectroscopy and ultraviolet–visible spectroscopy were used for the chemical characterization of the prepared solutions. Electrochemical characterization is performed by open circuit potential measurement, cyclic voltammetry and polarization measurements

Influence of blackberry leaf extract on the copper corrosion behaviour in 0.5 M NaCl

The research presented in this paper is focused on blackberry leaf extract (BLE) as a environmentally friendly corrosion inhibitor for copper in 0.5 M NaCl. The caffeic acid, quercetin-3-O-glucoside and kaempferol-3-O-glucoside were identified in BLE by using high-performance liquid chromatography (HPLC-DAD). The BLE functional groups were identified (ATR-FTIR). The electrochemical methods (potentiodynamic polarization, electrochemical frequency modulation and electrochemical impedance spectroscopy) show that BLE acts as a mixed type of inhibitor (max. IE is 97.19 %). The corrosion process is controlled by diffusion (BLE lower than 15 g/L) and charge transfer (15 g/L BLE).This is the peer-reviewed version of the article: Zdravković, M., Grekulović, V., Šuljagić, J., Stanković, D. M., Savić, S. D., Radovanović, M.,& Stamenković, U.. (2023). Influence of blackberry leaf extract on the copper corrosion behaviour in 0.5 M NaCl. in Bioelectrochemistry Elsevier., 151, 108401. [https://doi.org/10.1016/j.bioelechem.2023.108401

Electrochemical synthesis and characterization of copper (I) oxide

The quest and need for clean and economical energy sources have increased interest in the development of thin film cells technologies. Electrochemical deposition is an attractive method for synthesis of thin films. It offers the advantages of low synthesis temperature, low cost and high purity. Copper (I) oxide or cuprous oxide is an oxide semiconductor which is used as the anodic material in the form of thin film in lithium batteries and solar cells. The cathodic process of synthesis of cuprous oxide thin film is carried out in a potentiostatic mode from the organic electrolyte. The process parameters are chosen in that way to accomplish maximum difference between the potentials at which Cu2O and CuO are obtained. The electrochemical characterization was carried out by cyclic voltammetry. The electrodeposition techniques are particularly well suited for the deposition of single elements but it is also possible to carry out simultaneous depositions of several elements and syntheses of well-defined alternating layers of metals and oxides with thicknesses down to a few nm. Nanomaterials exhibit novel physical properties and play an important role in fundamental research. In addition, cuprous oxide is commonly used as a pigment, a fungicide, and an antifouling agent for marine paints. It is insoluble in water and organic solvents. This work presents the examinations of the influence of bath, temperature, pH and current density on the characteristics of electrochemically synthesized cuprous oxide. In the 'classic' process of synthesis, which is carried out under galvanostatic conditions on the anode, the grain size of the powder decreases with the increase in current density while the grain colour becomes lighter. The best commercial quality of the Cu2O (grain size, colour, content of choride) was obtained at the temperature of 80°C, concentration of NaCl of 3 mol/dm3 and current density of 400 A/m2