SU528355A1 - Electrolyzer for producing or refining metals - Google Patents

Description

This invention relates to the field of electrolytic production and refining of light metals from molten media.

Electrolyzers are known for producing crystalline precipitates of non-ferrous metals in molten salts.

In most of the known electrolyzers, the cathode sediment is extracted by cutting it with special tools (knives) from the cathodes both previously extracted from the electrolyte and rotating (disk, drum). When extracting cathode deposits in such electrolyzers, it is necessary to periodically interrupt the current on the cell of the electrolyzer (with the exception of rotating cathodes). In a number of cases, the electrolyte hardens by the time the precipitate is cut, as a result of which shear forces reach large values (up to 150 kg per 1 cm of the knife length). In some designs, sediment is cut directly in the electrolyte.

A known cell for producing and refining refractory metals from molten salts, comprising a bath with rectangular cathodes and anodes installed therein. The cut of the sediment is carried out directly in the electrolyte with special knives. Between the cells there is a cathode sediment bucket, which during the sediment cut-off

sinks to the bottom of the bath and goes under the cathode. After the cut, the bucket filled with sediment is removed from bath 1. A significant drawback of such an electrolyzer is the presence of complex movements of shearing and removing sediment devices in the molten salt medium, increasing the depth of the bath, the interpolar distance, etc.

Also known is an electrolytic cell for producing or refining metals, for example magnesium or aluminum, by electrolysis of molten salts at a temperature below the melting point of these metals, containing a semi-cylinder made up of a bath with vertically inserted electrodes.

The recovery of metal sediment from the bath is carried out as follows.

The cathode sediment is cut from the electrodes with knives and falls to the bottom of the cells. Next, the sludge is pumped out together with the electrolyte through special tubes and a collector lowered to the bottom of the cells into a filter located above the electrolyzer. The precipitate separates from the electrolyte and remains on the filter, and the electrolyte returns to bath 2.

The disadvantage of this cell is the complexity of the cathode removal operation.

sediment and anode sludge from the interelectrode space due to the complex construction of the electrolyzer itself and the moving parts of the pumps in the aggressive melt.

The pre-molded electrolyzer is characterized in that a shaft with scrapers attached to it is installed above the electrodes coaxially with the bath, and the width of the scrapers is commensurate with the distance between the electrodes. This makes it possible to simplify the operation of removing cathode sludge and anode sludge from the inter-electrode space.

FIG. Figure 1 shows the described electrolyzer with one collective cell in two projections; in fig. 2 - electrolyzer with a bunker in two projections.

The electrolyzer is a bath enclosed in a steel casing 1 lined inside with refractory bricks 2. Conventional or bipolar electrodes 3 are installed in the electrolytic bath. A shaft 4 with scrappers fixed on it is mounted above the electrodes in the center of the bath. cell 6. From above, the electrolyzer is closed by a lid 7. Sediment may not flow into the collecting cell, but into the bunker. In this case, the scraper 5 with a blade 9 attached to the hinge 8 moves the sediment to the grid 10. The electrolyte from the cathode sediment flows into the cell 11. Then, after turning the lattice, the precipitate enters the hopper 12. The potential on the anodes 13 and the cathode 14 is fed through the lateral current leads 15.

Electrolysis is carried out, for example, in a chloride or chloride-fluoride electrolyte using conventional or bipolar electrodes. Both soluble and insoluble electrodes can be used. In the latter case, the gases produced at the anode, for example chlorine, must be trapped in the electrolyzer. Following the formation of a deposit on the cathodes, a shaft with scrapers attached to it is driven. Cutting the sediment from the cathode directly into the electrolyte, especially when producing aluminum IUn magnesium, does not cause much effort. Slice the sediment, the scraper moves it along the bottom of the bath in the national cell or bunker.

which communicate with the bath workspace.

The electrodes can be placed without touching the bottom of the bath, or they can be installed in the lining. In this case, the sludge and sediment in each of the cells are not mixed. For the same purpose, porous diaphragms separating the anode and cathode spaces can be installed in the electrolyzer.

From the assembly cell, the cathode sediment is centrally extracted either in solid or in liquid form, for which the temperature of the salt melt in the collection cell is maintained above the melting point of the resulting metal. In the electrolysis cell there may be two collecting cells on each side of the bath. The cells can also be located above or below the bottom of the cell. When the precipitate is cut, the electrolysis process is not interrupted.

The electrolyzer can be used to obtain electrolytic powders of any metals or alloys deposited below their melting point.

Claims (2)

1.Avt. St. USSR 137269, cl. C 22C 3/02, 1961 2. US patent number 2512157, cl. 204-67, 1950