SU1633023A1 - Method of electroextraction of nickel from sulphate- chloride electrolyte - Google Patents

Abstract

The invention relates to the production of non-ferrous metals by an electrochemical method and can be used to produce nickel. The goal is to increase the safety of the 1 sa process and reduce costs by utilizing chlorine gas in the electrolyte volume. Nickel from the sulfate chloride electrolysis is used as nickel carbonate in the amount of 4.1-6 as a reagent for chlorine gas utilization. , 1 g / g of nickel or sodium carbonate deposited on the cathode in the amount of 3.6-5.4 g / g of nickel deposited on the cathode, or caustic soda in the amount of 1.4-4.1 g / g of deposited nickel. The solution of the reagent-utilizer is fed to the surface of the anode in a continuous flow along a closed loop. In the case of the use of nickel carbonate, the treated electrolyte is used as a catholyte for the deposition of nickel. 4 ep f-crystals, 3 tab., 3 Il. . i

Description

The invention relates to the production of non-ferrous metals by an electrochemical method and can be used to produce nickel.

The aim of the invention is to increase the process safety and reduce costs by utilizing chlorine gas in the electrolyte volume.

Figure 1 shows the anode in rectangular coordinates; FIG. 2 is a section A-A in FIG. 1, FIG. 3 is a section BB in FIG. 2.

Electrical extraction is carried out in an electrolytic cell, in which insoluble anodes and cathodes are alternately located in the diaphragms forming the cathode cells. Sulfate-chloride electrolyte is fed into each cathode cell at a rate of 18-25 l / h, and on the surface of the anodes a chlorine gas utilizer is used in a continuous flow along a closed circuit that covers the working and side surfaces of the anodes.

or a nickel-carbonate pulp in a de-anolyte, or sodium carbonate, or sodium hydroxide. The supply of reagents in this way ensures that the anode surfaces are washed away with a continuous stream of chlorine gas utilizer reagent.

In this case, nickel carbonate is introduced into the electrolyte in the amount of 4.1-6.1 g, sodium carbonate in the amount of 3.6-5.4 g, and sodium hydroxide in the amount of 1.4-4.1 g per 1 g of deposited carbon. nickel cathode. The process of nickel deposition on cathodes in an electrochemical reaction in an electrolysis bath is accompanied by the release of chlorine gas on the working surfaces of insoluble anodes. The chlorine gas utilization reagent introduced into electrolytes reacts with chlorine gas, resulting in the formation of nickel hydroxide (black hydrates), settling to the bottom of the electrolyzer and carrying the excess chlorine gas utilizer down with it, recycling it in the electrolyte volume. The spent electrolyte is removed from the bottom of the electrolyzer through a siphon device followed by the direction of the electrolyte being withdrawn for cleaning from cobalt (cobalt cleaning) or from iron and cobalt (iron-cobalt cleaning). In the case of the use of nickel carbonate as a chlorine gas utilizer reagent, the withdrawn electrolyte is filtered and returned to the cathode cells for electroextraction. Thus, self-sufficiency of the process of electroextraction with catholyte is achieved.

Nickel and chlorine ion content in the electrolyte do not change. In addition, the accumulation of impurities in the electrolyte (Fe, Co) does not occur, as they, due to their lower normal standard potentials, are first of all oxidized and precipitated in comparison with nickel.

Insoluble anodes are manufactured to implement the method.

The insoluble anode contains a conductive rod 1 connected to a metal plate 2 on which a slotted distributor 3 is fixed. The slotted distributor 3 has guide channels 4 and 5 that are horizontal and communicated with the input distribution box.

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chamber 6. The guiding linear channels 4 and 5 eakpyty rigidly fixed on the metal plate 2 housing elements 7 and 8 of the slotted distributor 3. With the formation at the bottom of the linear output slits 9 and 10. The input distribution chamber 6 in the area adjacent to the slot distributor 3, is equipped with transverse exit slit 11 communicated with guiding linear channels 4 and 5, the length of the guiding horizontal linear channels 4 and 5 exceeds the width of the metal plate 2, while the output ends 12 and 13 of the guiding linear channel 4 and 5, respectively, are closed with a deaf bottom 14 to form a metal plate 2 between it and the side end 15 of the second transverse exit slit 16, which communicates with the guide channels 4 and 5. The metal plate 2 has working surfaces on the main side surfaces 17 and 18, side the ends 15 and 19 and on the bottom 20.

Insoluble anode in the electrolysis bath works as follows.

Into the inlet distribution chamber 6, the reagent utilizer is supplied, which enters the linear guide channels 4 and 5, and from them, through the linear output slots 9 and 10, the recycling reagent flows to the main side (working) surfaces 17 and 18, through the transverse output slot 16 — at the side end 15. All the working surfaces of the anode, except for the lower end, are washed with a continuous stream of reagent so that they form around the working surfaces a film of chlorine gas utilizing reagent continuously moving downwards. When electroextracted on electrolytes with chlorine ions on the working surfaces of the anode, chlorine gas bubbles are formed, which immediately transfer to ionic state, utilizing chlorine gas in the electrolyte volume without the possibility of chlorine gas bubbles leaving the outer side continuously moving from above down film reagent.

Electroextraction of nickel is carried out in an electrolyzer, in which insoluble anodes and titanium cathodes with iridium-ruthenium coating are alternately arranged, with diaphragms of coralone forming cathode cells. Each cathode cell is fed with a flow rate of 20 l / h at 80dC a sulfate-chloride electrolyte of the following composition, nickel 80 g / l, chlorine ion 25 g / l, sulfate ion 150 g / l with copper impurities 2 mg / l, cobalt 10 mg / l, iron 1.0 mg / l, zinc 1 mg / l, lead Oh, 1 mg / l.

Through a gap of 3 mm wide slotted distributor, located at a height of 150 mm from the electrolyte surface, nickel carbonate is supplied in various quantities per 1 g of nickel deposited on the cathode in a continuous flow along the lateral surfaces of the anodes. The chlorine gas emitted during the electrochemical reaction on the working surfaces of the anode is utilized completely in the electrolyte volume. The spent electrolyte taken from the electrolysis bath with a nickel concentration of 80 g / l is filtered and returned to the electroextraction in the cathode cells.

In another series of experiments, sodium carbonate is supplied to the surface of the anodes in varying amounts through a slotted distributor.

In the third series of experiments, through a slot-hole distributor, lateral surfaces of the anodes with their coverage in a closed loop are fed with a continuous stream of sodium hydroxide in various quantities.

The results of the experiments are presented in table 1-3.

Monitoring the presence of chlorine gas in electrolysis baths is organoleptic.

The main technical and economic advantages of the proposed method as compared to the known one are to eliminate the possibility of chlorine gas leaks into the atmosphere due to guaranteed utilization of chlorine gas in the electrolyte volume, eliminating the need to build expensive special pipelines that need to transport chlorine gas, eliminating the need mounting special technological

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whom equipment for processing foam. The volume of installation and commissioning works is reduced by 40% in each electrolysis bath by eliminating the need to install special pipelines with special instrumentation and special valves and fittings. In addition, it is possible to conduct additional purification of the disintegrated anolyte from iron, cobalt, and other impurities.

Claims (5)

1. Electroextraction method of nickel from sulphate-chloride electrolyte, including deposition of nickel on the cathode, release of chlorine gas at the anode, introduction of chlorine gas utilizer reagent into the electrolyte, removal of spent electrolyte, which is characterized by cost reduction due to chlorine gas disposal in the volume of the electrolyte, the reagent - utilizer, which uses a compound selected from the group: nickel carbonate, sodium carbonate, caustic soda, is served in the aqueous phase to the surface of the anode in a continuous flow along a closed loop. 2. The method according to claim 1, wherein the carbon monoxide nickel is introduced in the amount of 4.1 to 6.1 g per 1 g of nickel deposited on the cathode is introduced into the previously disinflated anolyte. 3. The method according to claim 1, characterized by the fact that sodium carbonate is introduced in an amount of 3.6-5.4 g per 1 g of nickel deposited on the cathode. 4. A method according to claim 1, characterized in that the caustic soda is introduced in an amount of 1.4-4.1 g per 1 g of nickel deposited on the cathode. 5. The method according to claims 1 and 2, about t and which is due to the fact that after filtration, the spent electrolyte is used as catholyte. Table 1 1.4 g, upper limit 4.1 g per I G of nickel deposited on the cathode. / 2 J FIG. 3 # I-fi