SU1813806A1 - Process for preparing copper powder - Google Patents

Description

The invention relates to powder metallurgy, in particular to methods for producing copper powder by electrolysis.

The purpose of the invention is to obtain a homogeneous fine powder.

The method is as follows.

On the cathode tape, passed through the electrolyte vertically at a speed of 1-8 m / h, electrochemical deposition of copper from the sulfate electrolyte containing 8-25 g / dm ³ copper is performed. The distance between the anode and the cathode tape is accepted. constant and equal to 50-75 mm. Depending on the current density, the chemical composition of the electrolyte, the speed of the cathode tape and the interelectrode distance, both the structure and the particle size distribution of the resulting powder change. In this case, the current output increases. The vertical arrangement of the cathode tape allows one to obtain powders without any impurities, because sludge generated during electrolysis accumulates at the bottom of the bath.

Example. The inventive method was tested in laboratory conditions.

A solution containing 140 ± 10 g / dm ³ sulfuric acid and 7-30 g / dm ³ copper was used as an electrolyte. The deposition process was carried out at a cathodic current density of 12003400 A / m, an electrolyte temperature of 50 ± 2 ° C and a circulation of 4 l / h. The speed of the tape was varied from 0.5 to 8.5 m / h, and the interelectrode distance was from 45 to 80 mm. The duration of one experiment was 2 hours. For a comparative analysis, an experiment was conducted on the prototype (experiment 1, see table).

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The results of laboratory tests are shown in the table.

From the data given in the table it is visible. that achieve your goal from; experiments 4, 5, 10, 11, 13, 14, 15, 16, 17, 18, 20, and 21 follow. Other experiments do not meet the goal of achieving current efficiency and uniformity of powder particles (percentage of average particles).

Based on the data presented in the table, better results were obtained with the following parameters for maintaining

electrolysis process Current density, A / m 1300-3300 The electrolyte concentration, g / dm: copper 8-25 sulfuric acid 140 ± 10 The speed of the cathode of the tape, m / h 1-8 Interelectrode distance, mm 50-75

The use of the proposed technical solution compared to the technical solution selected as a prototype allows to increase the bath time up to 95% and current efficiency up to 90%, to obtain a narrow spectrum of particle size distribution of the powder, which does not require its separation, grinding and averaging. The advantages of the developed method include the establishment of the required mode for the production of this type of powder, which is carried out by changing the current density, copper content in the electrolyte and the electrolysis time achieved by changing the cathode speed.

Claims (1)

Claim A method of producing a copper powder, including electrolytic deposition of copper from sulfate electrolyte on a movable cathode tape, characterized in that, in order to obtain a homogeneous finely dispersed powder, the deposition is carried out on an electrolyte tape vertically passed at a speed of 1-8 m / h, and containing 8-25 g / dm ^{3 of} copper, at a cathodic current density of 1300-3300 A / m ² . Experiment Conditions Experiment Results Gf Raft- Soder- Soon Inter Exit Medium Percent Note p / p nost burning growth electronic by nyaya ve- particles current copper in move native ku,% mask middle A / m ² electronic niya distance particles great- roll tapes yanie, μm us (+0.1 g / dm ³ m / h mm μm),% Prototype 1 300- 12.8 0.54- - - 60-200 - All other pa- 1500A 0.96 dimensions in article 2 not shown 3 1000 5 0.92 20 76.51 1.23 52 Powder drop 4 1200 8 1,62 40 74.61 1.22 64 5 1300 10 2.23 60 77.29 1.24 86 6 1400 25 3.23 70 88.2 13,2 64 7 1500 fifteen 4.04 60 77.71 1.26 ⁷⁹ Bottom Tue 8 1600 8 13.45 80 79.28 1,56 56 Powder drop 9 1800 eleven 0.92 45 81.87 2.23 77 2000 20 6.72 25 75.31 1.87 80 Small interelectrode 10 distance eleven 2200 25 8.08 55 84.32 1.26 89 12 2300 14 1,62 fifty 86.89 1.37 89 thirteen 2500 thirty 13.45 55 71.24 1,67 58 Powder drop 2500 20 6.72 60 92.69 2,33 80 Table continuation Expo conditions Experiment Results No. Raft- Soder- Soon Inter Exit Medium Percent Note p / p current rating, A / m ² burning of copper in the electrolyte, g / dm ³ belt movement growth, m / h electrode distance, mm by ku,% the desired particle size, microns particles of medium size (+0.1 microns),% 14 2800 12 3.23 65 91.59 1.44 91 fifteen 2800 18 4.04 55 86.01 5.42 85 16 3000 24 4.04 fifty 92.41 2.73 87 17 3100 16 1,62 75 91.09 1,54 84 18 3200 21 6.72 65 92.84 2.88 87 19 3300 22 3.23 85 87.54 1.74 78 Large interelectrode distance 20 3300 25 8.08 75 81.02 3.21 92 21 3400 12 4.04 70 90.01 1.93 82 22 3500 28 13.45 55 75.55 2.41 49 Powder drop