Linyucheva O.V.

Copper Production from a Carbonate Ores by Electrowinning Method

A process of compact copper electrowinning from the solution obtained by leaching copper from the ore by sulfuric acid was discussed. It was shown that the ore leaching is advisable to carry out with 10 % hydrochloric acid for 30–40 minutes with intensive stirring of the mixture. Copper electrowinning process was done from a concentrated solution with a stepped reduction of the current density which was proportional to the copper ion concentration decreasing during the process. The comparison of the parameters of the real and theoretical calculated processes was performed.

Influence of Electroosmotic Phenomena on Transient Duration in Amperometric Gas Sensors

The work is dedicated to the 100th anniversary of the birth of great scientist-electrochemist, corresponding member of USSR SA L.I. Antropov and continues series of studies of transients processes in amperometric sensors. Reasons of differences in the duration of transient processes in the measurements, differentiated break from several minutes to several hours, allowing time for the values of the output current signal by 10 and 50 % of its stationary value to estimate the expected value of reliable sensor signal prior to its stabilization were revealed.

Electrochemical Sensor of Oxygen for Biological Liquids Based on Nanocrystilline Zn Oxide

In this paper, we propose to use nanocrystalline ZnO electrodes, obtained through zol-gel and electrochemical methods, as a sensitive element of dissolved oxygen sensor. We elucidate that electrodes have stable characteristics at electroreduction О2 in biological solutions. The average size of the obtained particles d makes up ∼10 nm. We determine the quantity of electrons on the discharge stage and the total quantity of electrons, participating in restoration reaction of oxygen.

Multistage Galvanostatic Method of Electrowinning Copper from Sulphate Solution of Copper Ore Leaching

This paper investigates the process of copper electrowinning from carbonate ore. Copper was leached by sulfuric acid solution. The obtained electrolyte was used for copper electrowinning. We show that step current lowering was the best method to obtain massive cathode deposit or copper foil with 100 % of current efficiency. We make theoretical calculations of the electrolysis process.

Electrochemical Gas Sensor for Determining Hydrogen Sulfide in Air and Technological Environments

In this paper, we determine the range of potentials, which shows electrochemical stability and corrosion resistance of titanium and catalytically active electrodes based on it in 5 m of HClO4 solution. We reveal that the current-free potentials of these electrodes comply with compromise potentials conjugate reduction reaction of adsorbed oxygen and oxidation of hydrogen sulfide in the presence of hydrogen sulfide. Based on studies of properties of the semiconductor oxide electrocatalysts of transition metals, gas diffusion electrodes are developed.

The Electrochemical Sensor of Carbon Dioxide with Manganese Dioxide Working Electrode

Relying on the electrochemical cell with the manganese dioxide gas-diffusion electrode, we develop the titanium-based galvanic-type sensor of carbon dioxide. Furthermore, we define the effect of such factors as the amount of manganese dioxide on the working electrode, the pH of solution in the sensor, the magnitude of diffusion resistance (the size of gas diffusion window), the internal resistance of electrochemical cell and the resistance of load resistor on the metrological characteristics of the sensor (the normalization of the current signal of sensor and the transient time 0,9).

The influence of auxiliary electrode polarization on transient processes in amperometric gas sensors

This study proves that the mode of transient performance in amperometric sensor can clearly indicate the excessive polarization of auxiliary electrode as a root cause of unstable signal or long transition period. These findings allow determining a dramatic decrease in the contact area of consumables auxiliary electrode (potential determining material) with its conductive skeleton that causes the sharp rise in polarization

The influence of determinate component adsorption on the time of transition processes in the amperometric gas sensors

The chemical sensors are the important elements of present-day resource-saving technologies and complex arrangements of the environment presservation. Among them the most useful are the amperometric gas sensors. They are inexpensive and have current signal registration as well as resistance against poisoning and overcharge. One of the directions of their further enhancement is the reduction of the reliable signal stabilization time that depends on the time of transition processes in the electrochemical sensor system.