RU2350694C1 - Electrolyte for electrosheet copper production by means of electrolysis - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to hydrometallurgy field and can be used with electrosheet copper manufacturing by means of electrolysis. Electrolyte contains, g/dm³: copper sulfate 135-280; sulfuric acid 70-100; cobalt cations 0.05-1.0; nickel cations 0.2-3.0; chloride-ions 0.0001-0.001; water is the rest.

EFFECT: improvement of electrosheet copper; receiving of plain, thin, flexible and easy-annealed electrosheet with constant behavior lengthwise the coil.

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Description

The proposed technical solution relates to the field of hydrometallurgy and can be used in the production of copper electrolytic foil by electrolysis.

A known method of producing copper electrolytic foil, mainly for the production of foil dielectrics for printed circuit boards, by deposition of copper from an aqueous solution on a rotating drum cathode under the influence of electric current. An aqueous solution of copper contains copper sulfate, sulfuric acid, gelatin, and chloride ions as surface-active additives in an amount of 0.001-0.005 g / dm ³ and 0.005-0.1 g / dm ^3, respectively (see Japan patent No. 49-31415 according to class C25C 1/12 for 1982).

The main disadvantages of this method are the low ductility of the tape, the increased roughness of one of its sides, the increased roughness (P a 1.5-3 μm), caused by the presence of chloride ions in the electrolyte, specially introduced to create the necessary topography of the surface of the tape to increase the adhesion of the foil to the dielectric. In addition, the foil obtained from the indicated composition of the electrolyte is difficult to anneal, which complicates the production of a “soft” tape with high plasticity suitable for the manufacture of plates for radiators for cooling internal combustion engines (ICE), for the manufacture of a protective shield for electric cables.

Known electrolyte for the production of copper tape with electrolysis, containing an aqueous solution of copper sulfate, sulfuric acid and chloride ions in the ratio respectively: 135-180, 70-100, 0.0001-0.001 g / dm ³ , and the rest is water (see patent for invention of the Russian Federation No. 2113546 according to class C25C 1/12, C22B 15/12 for 1995).

Although this electrolyte makes it possible to obtain a thin copper tape by the electrochemical method with predetermined mechanical properties, it has serious drawbacks leading to a deterioration in the quality of the tape.

First of all, there is a strong dependence of the mechanical properties of the tape on the electrolysis conditions, especially on the concentration of chloride ions and the temperature of the electrolyte itself, the control of which during the electrolysis is a complex operation. This affects the fact that, receiving a long ribbon on the same electrolyzer (more than 100 m per roll), a substantial fluctuation in mechanical properties is almost inevitable, including ductility, hardness, recrystallization temperature, and more.

In addition, an unnecessary effect appears in the form of rapid destruction at high current densities (30-60 A / dm ² ) of lead used as an anode material. Destroying, lead contaminates the electrolyte with fine suspensions of lead oxides, which leads to the formation of numerous dendrites (“crumbs”) on the surface of the tape.

These shortcomings greatly complicate the use of the tape in the manufacture of plates of cooling radiators on automatic equipment due to the rupture of the tape and the inability to form corrugations and obtain grooves and protrusions of the required size and size.

The technical task of the proposed solution is to obtain by electrolysis a smooth, thin, plastic, easily annealed copper strip with constant properties along the length of the roll.

This problem is achieved by the fact that in the electrolyte for the production of copper foil by electrolysis containing an aqueous solution of copper sulfate, sulfuric acid and chloride ions, cobalt and nickel cations are additionally introduced in the following ratio, g / dm ³ :

Copper sulphate 135-280 Sulphuric acid 70-100 Cobalt Cations 0.05-1.0 Nickel Cations 0.2-3.0 Chloride ions 0.0001-0.001 Water rest

The process of obtaining copper foil with a thickness of 0.02-0.1 mm is carried out on drum electrolyzers by separating copper from the electrolyte and electrodeposition on the outer surface of the drum constantly rotating around the axis. The electrolyte is specially prepared according to the claimed composition of the ingredients, served in the electrolyzer and carry out constant circulation at a certain speed. The process is carried out at a cathodic current density of 30-60 A / dm ² and an electrolyte temperature of 28-35 ° C.

Example

On a drum electrolyzer, in which the cathode diameter is 0.9 m, width 1.2 m, immersion depth 50%, at a cathodic current density of 35.4 A / dm ² from an electrolyte consisting of (g / dm ³ ) 160 - CuSO ₄ , 90 - Н ₂ SO ₄ , 0,0003 - Cl ^- , 1,0 Ni ²⁺ , 0,3 С ²⁺ , Н ₂ O - the rest, a copper tape was obtained with a thickness of 0,040 mm at a speed of rotation of the drum cathode of 14.8 m / h The thickness of the tape width is not more than 1%. The length of the tape in a roll weighing 250-300 kg is 580-720 m. The temporary tensile strength of the tape is 700-750 n / mm, the recrystallization temperature is 190-210 ° С. The roughness parameters of both sides do not exceed 0.5 μm. The mechanical properties of the tape are constant along the length.

When processing a batch of tapes on the automatic lines of a radiator plant, a good formation of corrugations of a given size and profile, obtaining cuts without breaks in the absence of failures and equipment shutdown were revealed. This made it possible to reorient the production of cooling radiators for internal combustion engines to copper tape obtained by electrolysis, instead of rolled copper tape.

According to the results of industrial tests, it was found that when cobalt cations are added to the electrolyte, the service life of lead anodes is increased by 50% and practically no “crumbs” are formed on the surface of the tape.

When the concentration of nickel and cobalt cations in the electrolyte is lower than 0.2 and 0.05 g / dm, respectively, the beneficial effect of the introduction of additives is not formed, and an increase in the concentration above the stated limits is not economically feasible due to their high cost, especially cobalt.

Using the proposed technical solution allows the electrolytic method to obtain a thin copper tape with constant specified mechanical properties, which are necessary for the production of cooling radiators from it for internal combustion engines. The above properties allow mechanical operations with it on high-speed automatic equipment without additional operations.

The performance of the electrolyte with the composition of the claimed ingredients for the production of metal tapes, mainly thin copper foil, allows to improve the quality of copper foil regardless of the time of its production and the parameters of the technological process of its production, to expand its scope and reduce operating costs for production compared with known electrolyte solutions for electrochemical production of copper foil for a similar purpose.

Claims (1)

An electrolyte for the production of copper foil by electrolysis, containing an aqueous solution of copper sulfate, sulfuric acid and chloride ions, characterized in that it further comprises cobalt and nickel cations in the following ratio, g / dm ³ :
Copper sulphate 135-280 Sulphuric acid 70-100 Cobalt Cations 0.05-1.0 Nickel Cations 0.2-3.0 Chloride ions 0.0001-0.001 Water rest