RU2610095C2 - Electrolyser for separation of fusible alloys by electrolysis in molten salts - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: electrolyser contains a bath, heated cathode and anode cavities separated and fixed by three vertical porous diaphragms impregnated with electrolyte. The anode cavity is formed by the diaphragm and the anode gasket made with a central partition having an U-shaped wall disposed therein, providing formation of the siphon windows in the bottom of the anode seal to overflow anode alloy, the anode gasket sidewall is provided with an inclined channel for flow of the anode alloy, and the cavities between anode and cathode are separated by spacers with the cutouts of the capillary channels of the siphon metals into the trap collections pressed against the bottom of the bath body.

EFFECT: exclusion of semi-products oxidation with the active easily oxidized metals Sn, In, Ga due to their drain on the sealed capillary siphon channels in the sealed collections, increase in the yield of the concentrates with a reduction in maintenance costs.

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Description

The invention relates to ferrous metallurgy, in particular to electrochemical methods for the separation of metals from a melt.

Known electrolyzer for refining low-melting metals [1 - Pat. No. 2450091], containing heated cathodic and anodic cavities, separated by vertical porous diaphragms impregnated with electrolyte, separated by annular gaskets with different angles of inclination of the inner walls with lower cutouts with the formation of capillary channels for the flow of metals into individual product collections.

The disadvantage of the cell is the need for regular shutdown for unloading and loading the anode bath and restart.

Known and adopted for the prototype [2 - Patent of Russia No. 2512724] an electrolyzer containing heated cathode and anode cavities separated by vertical porous vertical diaphragms impregnated with electrolyte, which in turn are separated by gaskets with cutouts to form metal drain channels into individual product collections. The anode gasket is provided with a central partition, and a U-shaped partition is inserted into the anode cavity to form siphon windows, and the side wall of the anode gasket is provided with an inclined drain channel of the anode alloy.

The disadvantage of the electrolyzer according to the prototype is that the channels of the product drain are located on the open surface of a parallel heated wall, which leads to the oxidation of more active electronegative metals and reduces the yield of finished products.

The purpose of the invention is to reduce the oxidation of intermediates of electronegative metals.

This goal is achieved by the fact that the gaskets between the diaphragms for draining the cathode and intermediate products are equipped with capillary siphon channels for drainage into collectors pressed against the cell body.

The technical result of the invention is to reduce the oxidation of active metals and thereby increase the yield of the product.

In FIG. 1 shows a cell in general form with a section along AA of the cathode cavity.

In FIG. 2 is a sectional top view of the electrolyzer.

In FIG. 3 shows an electrolyzer with a B-B section along the cavity of the cathode intermediate.

In FIG. 4 shows an electrolyzer with a section BB in the cavity of the anode intermediate

In FIG. 5 shows an electrolyzer with a section GG on the cavity of the anode.

The electrolyzer consists (Fig. 1, 2) of the wall of the housing 1 of the bath of heat-resistant electrical insulation material, for example fluoroplastic. The sealing fluoroplastic gasket 2 forms with the wall of the housing 1 and the diaphragm 3 an anode cavity 4 for the molten starting alloy. A current lead 5 to the anode (stainless steel) is fixed in the anode cavity 4.

On the opposite side of the bath, the cathode cavity 6 (Fig. 2) is formed by the wall 1 of the body, the diaphragm 7 and the cathode gasket 8. The cathode cavity 6 and the anode cavity 4 are separated by diaphragms 3,7,9 made of KT-11-c8 \ 3- quartz fabric THAT, which are alternately separated and fixed by spacers 2, 8, 10, 11. The diaphragms are made of quartz heat-resistant fabric of the KT-11-s8 \ 3-TO brand of satin weave, which withstands a layer of 6 cm of metal without permeability, but has a porosity of 50-60 % to absorb electrolyte.

A cut-out 12 with a capillary channel 13 (Fig. 1) is made in the wall of the cathode pad 8 to drain the cathode metal. The diaphragm 7.9 (Fig. 2) fixes the cathode pad 10 with the formation of a cavity in the gap between the diaphragms 7.9. A capillary channel 14 is made in the middle part of the cavity in the cathode pad 10 (Fig. 3) to drain the cathode intermediate.

The diaphragms 3 and 9 (Fig. 2) fixes the anode strip 11 with the formation of a cavity in the gap between the diaphragms 3.9. A cutout 15 with a capillary channel 16 (Fig. 4) is made on the side wall in the anode strip 11 to drain the metal of the anode intermediate.

The anode gasket 2 is provided with a central partition 17 (Fig. 5), and a U-shaped partition 18 is inserted into the anode cavity 4. The partition 18 in the lower part with the anode gasket 2 forms siphon windows 19. The side wall of the anode gasket 2 is provided with an inclined drain channel 20 waste metal.

The gaps between the gaskets 2, 8,10,11, diaphragms 3,7,9 walls 1 during installation are sealed with a high-temperature sealant type VGO-1.

Under the capillary 13 there is a collector 21 (Fig. 1) for the cathode product Under the capillary channel 14 there is a collector 22 for an intermediate product. Under channel 16 there is a collection 23 for anode industrial product. Under the channel 20 posted by the collection 24, offset from the collection 21.

Walls 1 of the bath body with ring gaskets 2, 8, 10, 11 are placed in a thermally insulating body 25 with a heater for controlled heating. The current leads of the anode 5 and cathode 26 are connected to a constant current source. Collections 21,22,23 are installed on the platform 27, hermetically spring-loaded are pressed to the bottom of the bath 1.

The cell operates as follows. The walls 1 of the body (Fig. 1, 2) of the bath are heated in a heat-insulating body 25 to a temperature of 220-340 degrees. The molten electrolyte of the composition, weight, is poured into the cavity of the anode 4, and the cavity of the cathode 6, and the cavity of the intermediate products (Fig. 2). %: 16-18 potassium chloride, 10-12 sodium chloride, the rest is zinc chloride, for wetting the capillaries of all diaphragms 3,7,9 from quartz fabric.

After a single impregnation of the tissues, an initial molten fusible alloy containing tin, lead, bismuth, indium, cadmium, gallium (for example, waste from the production of thermometers, production of thermal fuses using Byda alloys) is poured into the anode cavity 4 and the anode current lead is inserted 5. The direct current is turned on, and the current strength is set.

From the molten alloy in the anode cavity 4, the electronegative metals In, Ga, Cd, Sn are ionized and diffuse through the electrolyte in the capillaries of the diaphragm 3 and accumulate between the diaphragms 3, 9.

At the same time, due to the higher concentration of electropositive lead, ionization of a certain amount of tin and lead also occurs. Lead ions also diffuse through the electrolyte in the capillaries of the diaphragms. Due to a change in the voltage at the entrance to the next diaphragm, more electropositive metals are discharged at the diaphragm 9 and accumulate in the form of an anode by-product of Pb, Sn, In, Cd, Ga. After the accumulation of the intermediate product in the gap to the level of cutout 15 (Fig. 4), the melt siphons through the capillary channel 16 in the gasket 11 into the collector 23 as an anode intermediate product (mainly lead).

At the same time, the more electronegative metals Cd, In, Ga and partially Sn are ionized and diffuse through the diaphragm 9, are discharged due to the voltage drop at the diaphragm 7, and accumulate in the cavity between the diaphragms 9, 7 in the form of an intermediate product of Cd, Sn, In, Ga. As they accumulate more than the level of channel 14, the intermediate product is discharged into a collection 22 (mainly tin) (Fig. 3).

During the accumulation of the intermediate, ionization of electronegative Cd, Ga, In and their diffusion in the electrolyte by capillaries through the diaphragm 7 with deposition on the cathode 26 occurs simultaneously. As the cd cathode concentrate 6 accumulates in the cathode cavity 6 to the cut-out 12 (Fig. 1), the alloy siphons along capillary channel 13 in the collection 21. As the level of alloy of the anode cavity 4 decreases, the initial alloy is added. Periodically weaken the clamp of the base 27 and replace the collectors 21,22,23,24. The electrolysis process continues until the collectors are filled and the level in the anode cavity decreases.

The anode alloy depleted in electronegative metals is displaced along the channel of FIG. 5 19, along the gap between the baffle 17 and 18 along the second channel 19 and flows through the drain 20 into the collector 24 (low-oxidizing bismuth with lead admixture).

The technical result of the distinguishing feature is that intermediates with the active easily oxidizing metals Sn, In, Ga flow into the collectors through sealed channels into the sealed collectors, which eliminates their oxidation, increases the yield of concentrates with a decrease in maintenance costs.

The proposed electrolyzer with vertical diaphragms allows the initial multicomponent low-melting alloy of complex composition to be divided into four selective concentrates without loss in the form of removal oxides. Metals in individual products are concentrated 2-3 times in comparison with the initial alloy composition. The cell operates in a continuous mode with periodic reloading of the initial alloy and replacement of collectors.

An example of testing a model of an electrolyzer: Before heating the cell to a temperature of 330 degrees, 10 g of the electrolyte of the composition were poured into the cathode and anode cavities: 17%, potassium chloride, 11% sodium chloride, the rest was zinc chloride. A portion of 160 g of the alloy composition, weight. %: bismuth 39.8%; tin 25%; lead 20%; cadmium 8; indium 6.2%; gallium 1.0; melted and poured into the anode cavity. A direct current of 2 A and a voltage of 20 V was supplied to the current leads. After every 6 hours, 40 g of the initial alloy was added twice to the anode cavity. Electrolysis continued for another 20 hours. Received 19 g of a cathode product containing: 0.1% gallium, 0.3% indium and 99.5% cadmium, with a recovery of 98.5%. Near-cathode industrial product obtained 17 g, containing: 0.65% lead; 0.1% cadmium; 13.9% gallium and 83.7% indium, with a recovery of 96.2%. Anodic by-product obtained 105.5 g, containing: 0.47% indium; 0.1% bismuth; 44.8% lead and 54.5% tin, with a recovery of 96%. In the anode alloy weighing 98.4 g, bismuth is concentrated to its content of 95.5%; and the tin content of 2.41%; lead 0.49%; and the content of indium, gallium is less than 0.01%. Total oxides are 0.45%, and in the analogue example 3.3%. An example shows that four separate selective alloys suitable for solders are obtained from an alloy of fusible waste.

Literature

1. RF patent No. 2450091 - Electrolyzer for the separation of low-melting alloys into selective concentrates, IPC C25C 7/04 Published 05/10/2012

2. RF patent №2512724 - Apparatus for continuous separation of metals from waste alloys by electrolysis in molten salts, IPC C25 c7 / 00.

Claims (1)

An electrolyzer for separating waste of fusible alloys by electrolysis in molten salts into selective concentrates containing a bath heated by the cathode and anode cavities, separated and fixed by three porous vertical diaphragms saturated with electrolyte, which in turn are separated by ring gaskets with metal drain channels made with capillary cutouts metal siphon channels, into individual collections of cathode product, cathode intermediate product, anode intermediate product and spent anode alloy, wherein the anode cavity is formed by a diaphragm and an anode gasket with a central partition with a U-shaped partition placed in it, providing siphon windows for overflowing the anode alloy in the lower part with the anode gasket, while the side wall of the anode gasket is made with an inclined channel for the drainage of the anode alloy, in which the collections of the cathode product, cathode intermediate product, anode intermediate product and spent anode alloy are mounted on the platform and pressurized against the bottom of the bathtub s with the possibility of periodic disconnection.

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