Electrolysis is widely used in metallurgy for receiving pure metals. Process is conducted with soluble or with nerastvoriyomy anodes in solution or in fusion of salts.
In the first case the anode sluyozhit the crude metal. It is transferred in the electrolytic way to solution, and then in the cleaned look is besieged on the cathode. Elektroliyotichesky refinement (— to clean from the fr. word "raffiner") copper can be the example of electrolysis with the soluble anode.
Electrolysis process proceeds according to the above described scheme in the electrolytic bath filled with solution of sulfate CuS04 copper; as anodes serve the plates cast from the crude copper between them sheets of pure copper are located thin (1 mm). At electrolysis copper of anodes passes into solution, and then osazhyodatsya on cathodes; impurity drop out on the bathtub bottom in the form of slime (deposit). The electric power expense at the same time makes 300 kWh on ton. Electrolytic copper contains less than 0,1% of impurity. It very significantly increases its udelyyony conductivity. The copper specific conductivity with impurity (about 1,5%) 57, and electrolytic copper - 61. High purity of metals is suyoshchestvenny advantage of the electrolytic way of their receiving.
Receiving aluminum from kriolitoglinozemny fusions can be the example of electrolysis in the melted environment with the insoluble anode. The bottom of the bathtub (hearth) serves as the electrolyzer cathode, and coal blocks, podveshenyony in the bathtub — the anode. The bathtub is filled with molten electrolyte which temyoperatura at the normal course of process has to be about 950 °C. This temperature is maintained by heat generated by the current passing через the bathtub. Alumina electrolysis (aluminum oxide) causes its disintegration on the metal aluminum which is emitted on the cathode at the bottom of the bathtub, and on кислород. The last with carbon of the anode forms SO carbon monoxide and uglekisyoly C02 gas. Owing to electrolysis the content of alumina in electrolyte decreases therefore for maintenance of concentration of electrolyte of the peyoriodicheska alumina is added to it, and electrolyte mixes up. 17 500 kWh of the electric power are spent for receiving 1 t of aluminum.
In general, on electrolysis of metals in fusions it is required considerably bolyyoshy expenses of the electric power, than on electrolysis in water environments. But for the number of metals electrolysis is possible only in fusions.
The electrometallurgy of aluminum is one of the largest promyshyolenny consumers of electricity therefore construction of the sotvetstvuyushchy plants near sources of the cheap electric power — powerful hydroelectric power stations is reasonable (for example, the Dnieper aluminum plant near Dnepyoroges).
The electrolysis scope in the chemical promyshlenyonost is very wide. In particular, by electrolysis the number of the chemicals, neobkhodiyomy for production of mineral fertilizers turns out.
Apply to receiving very pure hydrogen and oxygen электролиз water solution of the caustic natr at nickel electrodes. Hydrogen in hiyomichesky reactions is similar to metals therefore it is emitted on the cathode, and on the anode oxygen is emitted. The electric power expense for receiving 1 m3 of the vodoyorod and 0,5 m3 of oxygen makes 4,5 kWh.Top