CS243100B1 - Electrolyser for metal recovery and regeneration - Google Patents

Abstract

Electrolyzer for the recovery and regeneration of metals by electrolysis of solutions, consisting of a tank with electrodes which, together with diaphragms, define cathode and anode spaces open from below. The solution of the electrolyzer consists in that the cathode and/or anode spaces and/or partitions of the electrolyzer are provided with openings for overflow and circulation of the electrolyte between the cathode or anode spaces and the non-electrode spaces. In order to remove the precipitated metal, the cathodes are extendable and surrounded by scraping knives at the point of passage through the lid of the electrolyzer. The cathodes are flexibly attached to the electrolyzer and are firmly connected to the vibrating device. For safety reasons, the cathode and anode spaces are separated between the electrolyte level and the lid of the electrolyzer by impermeable partitions.

Description

(54) Electrolyser for metal recovery and regeneration

Electrolyser for the recovery and regeneration of metals by electrolysis of solutions, consisting of a bath with electrodes, which together with diaphragms define the bottom open cathode and anode spaces. The solution of the electrolyzer consists in that the cathode and / or anode compartments and / or the electrolyzer compartments are provided with openings for the overflow and circulation of the electrolyte between the cathode or anode compartments and the extra-electrode compartments. In order to remove the deposited metal, the cathodes are retractable and surrounded by scraping blades at the point where they pass through the electrolyzer lid. The cathodes are attached resiliently to the electrolyzer and are firmly connected to the vibration device. For safety reasons, the cathode and anode compartments are separated between the electrolyte level and the electrolyzer lid by impermeable partitions.

and

The present invention relates to an electrolyser for recovering and recovering metals.

The deposition of metals from aqueous solutions in powder or dendritic form is applied, for example, in the recovery of depleted baths used to etch printed electrical connections or in recovering metals from waste solutions containing metals in the form of soluble salts. So far, these processes have been carried out in diafragm-free electrolysers, in which intensive electrolyte mixing has not been ensured and the transport of ions to the cathode has therefore not been sufficient. The gas spaces above the electrodes were not separated and the resulting gases and vapors escaped into the surrounding atmosphere. This caused pollution of the working atmosphere and, in addition, there was a risk of explosion of an explosive mixture of hydrogen and air in case of insufficient ventilation. The metal deposited on the cathodes was removed after removal of the cathodes from the electrolyser. It has also been proposed to use rotary cathodes that would be continuously scraped during electrolysis (for example, German Patent No. 1937,523). The disadvantage of this procedure, however, is a more complicated device with a higher failure rate.

These drawbacks are overcome by the electrolytic recovery and regeneration electrolyzer of the present invention, comprising an electrode bath which, together with a diaphragm, delimits the cathode and anode compartments from below open, the cathodes and / or anodes and / or baffles of the electrolyzer being provided with overflow openings. electrolyte circulation between cathode or anode compartments and extra-electrode compartments. In order to remove the deposited metal, the electrodes of the electrolyser are retractable and surrounded by scraping blades at the point where they pass through the electrolyzer lid. In order to reduce dendrite growth through a diaphragm, which would result in an interelectrode short circuit, it is expedient if the cathodes are resiliently attached to the electrolyzer and firmly connected to the wavelength device. An increase in the safety of work is achieved by separating the anode compartments and cathode compartments between the electrolyte level and the electrolyzer lid by impermeable partitions.

The electrolyte circulation ensures intensive stirring, thereby increasing the rate of ion transport to the cathode and pumping more concentrated electrolyte from the bottom of the electrolyzer into the interelectrode spaces. The mixing of the catholyte and the anolyte is considerably limited, which in some systems can significantly increase the electrolysis current yields. For example, in obtaining copper from the etching baths, the access of oxygen from the anolyte to the cathode is greatly reduced in the electrolyzer so that the copper ions in the cathode compartment are not re-oxidized to copper and the current yields of the electrolysis are higher. Non-porous bulkheads above the electrolyte level prevent the mixing of gases produced on the electrodes, thus eliminating the risk of an explosive mixture. The gases are discharged separately from the enclosed gas spaces into the external atmosphere either directly or through the absorber. This avoids polluting the atmosphere in the production hall. During electrolysis, the cathodes can be removed without disassembly. Upon ejection, the deposited metal blades of the blades fixed to the cell cover scrape off the metal and fall to the bottom of the cell. The conical shape of the bottom allows easy removal of the powdered metal when the electrolyzer is discharged. The vibration of the cathodes during electrolysis leads to the release of the metal from the cathode surface and prevents the metal dendrites from penetrating the diaphragm to the anode, thereby causing a short circuit.

Fig. 1 shows an example of the structure of the electrolyser according to the invention, Fig. 2 shows a cross-section of one cathode space, and Fig. 3 shows a detail of an electrolyser element enabling wiping of the metal deposited on the cathode.

The metal recovery and regeneration electrolyzer of Figures 1 and 2 comprises a series of cathodes 1 and anodes 2 separated by diaphragms 3. The distance between the cathode and the diaphragm must be chosen as a compromise between the requirement to achieve a sufficiently high flow rate at the cathode (small distance) and to prevent metal dendrites from growing into the diaphragm, on the other hand. 1) connected to the inter-electrode compartments 4, 5, on the one hand through the apertures 16 at the electrolyte level and on the other side in the lower part of the electrolyzer. 3) the blades of the blades 7 attached to the electrolyzer cover 8 are adjacent. The cathodes 1 are attached to a plate 9 on which the vibrator 10 is attached. The plate 9 is springed from the electrolyzer cover 8 by a flexible pad 13 which simultaneously seals the connection of the lid 8 to the cathodes 1 and prevents hydrogen leakage into the atmosphere. The cathode plate 9 can be pulled out of the electrolyser by means of a lever device, scraping off the deposited copper.

During electrolysis, the electrolyte in the anode compartment rises by the gas exuding on the anode 2 and flows through the apertures 16 in the anode 2 into the electrode compartment 5 '(FIG. 1j). The cathode space 4 rises and falls into the extra-electrode space 4 'due to the gas excreted on the cathode 1, whereby it drops and is cooled after degassing (FIG. 2).

Claims (3)

Subject An electrolyzer for obtaining and regenerating metals, comprising an electrode bath which, together with the diaphragms, delimits the cathode and anode compartments from below open, characterized in that the cathodes (1) and / or the anodes (2) and / or the electrolyzer partition (15) are provided with holes (16) for overflow and electrolyte circulation between cathode (4) or anode (5) spaces and microelectrode spaces (4 ', 5'). OF THE INVENTION Electrolyser according to claim 1, characterized in that the cathodes (1) of the electrolyser are retractable and surrounded by scraping blades (7) at the point where they pass through the electrolyzer lid (8). 3. An electrolyzer according to claim 2, characterized in that the anode compartments (5) and the cathode compartments (4) are separated from one another by an impermeable barrier between the electrolyte level and the electrolyzer cover (8).