Electrochemical synthesis of nickel-aluminium oxide system from metals obtained by ore processing

Separate and combined electrochemical oxidation of aluminium and nickel has been conducted by alternating current of industrial frequency. Concentration increase of electrolyte solution (sodium chloride) in the range from 3 to 25 wt. % and current density from 0.5 to 1.5 A/cm{2} was found to result in the increasing metal oxidation rate, excluding aluminium oxidation which oxidation rate is independent of the electrolyte solution concentration. At the current density of 1.5 A/cm{2} the products of separate oxidation of nickel and aluminium are nickel oxyhydroxides, nickel hydroxides and aluminium oxyhydroxide (boehmite), respectively. In addition to these compounds, the nickel-aluminium oxide hydrate is included in the products of nickel and aluminium co-oxidation. Its content grows with the increasing electrolyte solution concentration. Varying the concentration and current density within the limits indicated, the nickel-aluminium oxide system with nickel oxide content from 3 to 10 wt. % is produced

Solution Transformation of the Products of AC Electrochemical Metal Oxidation

Electrochemical oxidation of copper and aluminium using alternating current of industrial frequency results in the formation of non-equilibrium products. Their transformations during the ageing in sodium chloride solutions of different concentrations have been considered. According to X-Ray diffraction confirmed by TG/DSC/DTG analysis, irrespective of solution concentration, the ageing products consist of aluminium oxyhydroxide (boehmite, AlOOH), copper-aluminium carbonate hydroxide hydrate (Cu-Al/LDH) and copper chloride hydroxide (Cu[2](OH)[3]Cl). The increase of the solution concentration leads to Cu[2](OH)[3]Cl formation and makes difficulties for metal oxide carbonization to Cu-Al/LDH. Ageing in highly diluted solution contributes not only to Cu-Al/LDH formation but also boehmite hydration that is verified by IR-spectra. The pore structure characteristics have been also discussed. They do not significantly depend on phase composition and vary in ranges of 161.2-172.6 m{2}/g (specific surface areas), 0.459-0.535 cm{2}/g (total pore volumes). Pore size distributions reveal that a pore structure is predominantly formed by pore with the sizes from 3 to 22°nm; 3.6°nm is the size of pores with the largest pore volume

AC Electrochemical Copper and Aluminum Oxidation in Sodium Acetate Solutions

Electrochemical copper and aluminum oxidation using alternating current of industrial frequency was carried out in an aqueous sodium acetate solution. Simultaneous oxidation of metals accelerates copper oxidation, but does not significantly influence the aluminium oxidation rate. It results in the preparation of the copper-aluminum oxide system with a high content of copper oxide (up to 70 wt %). High energy consumption due to the voltage loss to overcome the resistance of the oxidation product layer on the electrode surface considerably limits the process and its product application. Furthermore, the chemical aluminum oxidation in alkaline medium of an aqueous sodium acetate solution instead of electrochemical one does not result in the power-saturated, nanosized metal oxide formation. The results obtained do not only underline the new technology of nanomaterial production, but also allow scientists to consider the mechanisms of the metal oxidation AC-process

The Porous Structure of Copper-cadmium Oxide System Prepared by AC Electrochemical Synthesis

The porous structure of nanoparticles of copper-cadmium oxide system prepared by AC electrochemical synthesis in sodium chloride with a concentration of 3, 15, 25 wt. % has been studied. The obtained data indicate that at a higher current density and sodium chloride concentration of 3% wt. in the electrochemical oxidation of cadmium and copper products are formed with the structure of mesopores and channels. In this case, the specific surface area has the greatest value (19.4 m{2}/g) and a maximum pore volume (0.0778 cm{3}/g). Thus, the obtained data allow predicting the operating parameters of the electrolysis to obtain a copper - cadmium oxide system of a predetermined porous structure

Vibration Briquetting of Ash of Combined Heat and Power Plant

Ash and slag materials of combined heat and power plant (CHPP) are a unique resource that can be successfully used in construction, road and agricultural industries. However, their industrial use is accompanied with significant organizational and technical problems. Granulation of coal ashes improves the conditions of their storage and transportation, allows mechanizing and automating the subsequent use, increases productivity, improves the working conditions and reduces the loss of raw materials and finished products. This paper proposes a method of compacting of Seversk CHPP (Russia) ash by vibration briquetting using a number of binders (polyvinyl alcohol, glyoxal, liquid sodium glass). The main characteristics of Seversk CHPP ash such as chemical composition, particle size distribution, bulk density, content of unburnt carbon and radioactivity have been determined. Investigation of the effect of binder concentration on the static strength of granules revealed that the increase of binder concentration results in the growth of static strength of the dried granules that reaches a maximum at the concentration of 10 wt %: 0.28 MPa for polyvinyl alcohol, 0.63 MPa for glyoxal and 0.40 MPa for liquid sodium glass

Joint Destruction of Cadmium and Copper at Alternating Current Electrolysis in Sodium Hydroxide Solution

The dependence of the metal oxidation rate on the current density and temperature of joint destruction in sodium chloride was studied. It is established that the dependence of the oxidation rate of copper is linear and generally do not differ from the dependencies established at individual oxidation of copper in the solution of sodium chloride with concentration 46.5% wt. In contrast to the oxidation rate of copper, the oxidation rate dependence of cadmium has extreme character and the oxidation rate of cadmium at its joint oxidation of copper increased in 2-3 times indicating that the mutual influence of electrodes at the electrochemical process with alternating current. Thus, the obtained dependences can predict operating electrolysis parameters a obtain copper-cadmium oxide system of the given composition