UA66091A - Method for utilization of the worked-out lead-acid accumulators - Google Patents

Abstract

Method for utilization of electrolyte of worked-out lead-acid accumulators is realized in the infrastructure of the by-product coke plant where neutralization of the electrolyte is performed by waste soda solution of the works for vacuum-carbonate sulfur purification with removal of hydrogen sulfide; amount of soda solution is determined according to the reaction of neutralization of the sulfuric acid of the electrolyte with addition of 5 % weight more; the metals present in the neutralized solution are precipitated by adding to it 2 % solution of sodium sulfide; the solution obtained is supplied to the phenol sewage of the by-product coke plant; the precipitated metal pulp is discharged forthe following processing, and the gas is continuously sucked out by the system of the coke gas purification.

Description

The invention relates to technologies for recycling electrolytes of spent lead-acid batteries with the precipitation of heavy metals from it. This invention can be used in the automotive industry or where this recycling is carried out.

The electrolyte is a solution of sulfuric acid grade "4" according to GOST 4204-77 in distilled water according to

GOST 6909-72 and corresponds to TU 6-09-5334-87, where the density at 157C should be 1.27--0.005g/cm3, which corresponds to a sulfuric acid concentration of 3795 wt. In addition, the content of iron in the electrolyte is limited - no more than 0.0003905, ammonium salts - no more than 0.001965.

At the Donetsk plant of chemical reagents, several dozen samples from different batches of spent electrolytes were analyzed, and their composition was determined. The results of the analyzes are presented in "Analytical passports". It was established that the spent electrolyte is a transparent liquid with a small amount of mechanical impurities. After settling, the mass fraction of the solid residue was about 0.02905.

The composition of the clear liquid: wt. share of sulfuric acid, 90 15-28 wt. iron content, 95 to 0.0018 wt. the proportion of lead, 95 to 0.0005 wt. proportion of antimony, 95 to 0.0005 wt. share of ammonium salts, 95 to 0.00012 wt. the proportion of arsenic, 95 to 0.0003 wt. the proportion of chlorine compounds, 95 to 0.0001

The composition of the solid residue of spent lead-acid batteries - lead ions -6195 mab., that is, the sediment is mainly lead sulfate.

As can be seen from these analyses, the iron content is two times higher than the norm, the content of other metals is twice the norm.

Therefore, the process of disposing of the electrolyte of used lead-acid batteries consists not only in the neutralization of sulfuric acid, but also in the removal of heavy metal ions of lead, antimony, and iron from the solution, which cannot be discharged into the sewer in the form of wastewater.

There are various ways of disposing of the electrolytes of spent lead-acid batteries: 1) a method of disposing of the electrolyte by neutralization with ammonia water; 2) method of disposal of electrolyte with lime solution; 3) method of disposal of electrolyte with milk of lime; 4) neutralization with soda ash. (Baranov A.A., Mykulyak O.P., Reznyakov A.A. "Technology of secondary non-ferrous metals and alloys", Kyiv, "Vyscha shkola", 1988, p. 120; Semenov G.A., Efremov N.L ., Baranov M.Y. "Organization of procurement and processing of scrap and waste of non-ferrous metals", Metallurgy, M., 1981, p. 240, Reference book edited by Y.P. Kupryakova,

M., Zkonomyka, 1984, p. 40 "Secondary material resources! of non-ferrous metallurgy. Scrap and non-ferrous metal").

Each of these methods completely neutralizes the sulfuric acid of the electrolyte.

Neutralization of the spent electrolyte with caustic soda proceeds according to the formula: nyo, -i2gmaon - Ma»5O, nagno

After the completion of the reaction, precipitation did not occur, the metals remained in solution.

Neutralization of spent electrolyte with milk of lime proceeds according to the formula: nyo, -Saon)" - Sazo, nagnyo

After the neutralization reaction, a precipitate of calcium sulfate (gypsum) fell out. Metal impurities remained in a dissolved state.

Neutralization of the spent electrolyte with lime proceeds according to the reaction: nyo, nCasSo»z to Sazo, -nyo-SoO,

After carrying out the neutralization reaction with lime, calcium sulfate precipitated. Metal impurities remained in a dissolved state.

Neutralization of the spent electrolyte with soda ash takes place according to the reaction: nyo, MassSo»z v Mazo, -nyo-SoO, T

After carrying out the reaction of neutralization with soda ash, precipitation did not occur, sodium sulfate, as well as metals, remained in solution.

The disadvantage of all the above-mentioned methods of electrolyte neutralization is the presence of dissolved heavy metals in the neutralized solutions. Such solutions are not discharged into the sewers according to the existing legislation of Ukraine - it is necessary to remove metals from the solution. In addition, all components of the spent electrolyte neutralization process require their purchase: caustic soda, lime, milk of lime, soda ash, and these are quite significant costs not only for the purchase of the product, but also for its transportation, storage, organization of the technological process, and its implementation. ..

The method of neutralization of spent electrolyte with soda ash is chosen as a prototype, because with the appropriate ratio of reagents, the sulfuric acid of the electrolyte is completely neutralized, but the problem of removing impurities of heavy metals and iron from the neutralized solution is not solved.

The invention is based on the following task: to implement a method of recycling the electrolyte of spent lead-acid batteries in the infrastructure of a coke chemical plant, to neutralize the electrolyte with the spent soda solution of the vacuum-carbonate desulfurization plant of the coke gas purification plant from hydrogen sulfide, to additionally remove all metals from the solution, and neutralized and cleaned of metals use the solution in technological processes of coke production.

The task is solved by the fact that the method of recycling the electrolyte of used lead-acid batteries, which consists in neutralizing the electrolyte and precipitating metals from it according to the invention, is implemented in the infrastructure of a coke chemical plant, where the neutralization of the electrolyte is carried out with the spent soda solution of the vacuum carbonate desulfurization plant of the coke gas purification plant from hydrogen sulfide during its mixing, while the amount of soda solution is determined according to the reaction of neutralization of sulfuric acid of the electrolyte with the addition of another 595 weight of soda solution; the metals present in the neutralized solution are precipitated by adding to the neutralized solution 290 sodium sulfide solution in a ratio of 2:1 (2 parts by weight of the neutralized solution to 1 part 295 sodium sulfide solution), the resulting solution is transferred to the existing phenolic effluents of the coke chemical plant, the pulp of precipitated metals is merged for further processing; gases formed in the process of neutralization of the electrolyte and in the process of precipitation of metals are constantly sucked into the coke gas purification system.

Neutralization of the electrolyte of spent lead-acid batteries in the infrastructure of coke-chemical production, where there is a vacuum-carbonate desulfurization of coke gas from hydrogen sulfide with a waste - soda solution, allows you to use this spent soda solution of cleaning coke gas for electrolyte neutralization.

Gases released in the process of neutralization of the electrolyte are sucked by the vacuum system of the coke gas purification plant. Classical mixing of the electrolyte with the spent sodium solution of the vacuum-carbonate desulfurization and with the additionally introduced solution of 295 sodium sulfide solution for the precipitation of metals ensures both uniformity and intensification of the reaction of neutralization of sulfuric acid and the reaction of precipitation of metals. After the neutralization of the electrolyte and precipitation of heavy metal impurities, a neutralized solution and pulp sediment of precipitated heavy metals are formed during settling. The neutralized solution is submitted for further disposal together with phenolic effluents according to the classic scheme of processing phenolic waters of coke chemical production. The sediment of heavy metals, in the form of a pulp containing lead, antimony, iron, is transferred for further processing during the disposal of the scrap battery itself.

The use of coke chemical production to neutralize the electrolyte with spent soda solution of the vacuum carbonate desulfurization of coke gas and processing of spent acid gases in the coke gas purification system significantly reduces the costs of organizing and implementing this technological process, because the use of the waste product of coke chemical production - soda solution as a reagent - allows to realize waste-free coke gas purification technology; neutralization gases and gases formed during the precipitation of metals are sucked by the existing coke gas purification system in the infrastructure of the coke chemical plant, the neutralized solution is transferred to the phenolic effluents of the same coke chemical plant.

In addition, the processes of dosing solutions, their mixing, and removal of heavy metals into the sediment using a 295% solution of sodium sulfide are used. The sediment itself is sent for additional processing in the battery scrap recycling technology.

The soda solution of the workshop for vacuum-carbonate purification of coke gas from hydrogen sulfide has the following chemical composition (fluctuations in composition are insignificant):

Ma2oz 35-40g/l; mansoz 15-20g/pl;

But 0.5-1.0 g/l;

Mag52O3 20-30g/l;

Ma"Re(CH) in 5-10 g/l;

MagZSM 175-185g/l; mass up to 0.5 g/l

Ma»zO4 20-30 g/l

The total sulfur content is 78-81g/l.

The electrolyte of spent lead-acid batteries is a 15-2895 solution of sulfuric acid, in which there are impurities of heavy metals lead (0.01-0.0795 wt.), iron (0.01-0.0795 wt.) antimony (0.004- 0.0295 mabs.).

The main reaction of the electrolyte disposal method is the reaction of neutralization of the sulfuric acid of the electrolyte with the spent soda ash solution of the vacuum-carbonate purification of coke gas from hydrogen sulfide:

Ma»SO»z nyo, - Mao, -nOoiSo, T

In addition, there are other reactions: gmanso» -Nbo, - MabO, Х СО» T я2нО

Ma»52O3 nyo, - Ma»ZOH - Ma»ZOH -Vv-BO2 T nyo

ZMa2»52O3 no, - ZMa25O, avno

Ma»52Oz nyo - Mazod noz T

Sodium rhodanite partially decomposes: гмавсСм--2нво, ЗНО - 2МН. НО» --Ма»5 - СО5-СО» T

Some compounds of the spent solution react with impurities of heavy metals in the electrolyte:

Ro" yin - ROB NN? T

Рря-Мад(гесн) - RBZ|Be(SM) in Ky rny - 502583 NN"

Be?" -MaResnN)v - ReDge(SM) c) Ky 25095 4 ZMa»5 - 50253 1.

Ro? 4-M»5 - РББ 4. yaMa»

Be?" 4 Ma»b5 - Ge5 in 2Ma"

For complete precipitation of heavy metal impurities to the neutralized solution, a 2956 solution of sodium sulfide (Mag5) is added in a ratio of 2:1. 25095 3 ZMab - 5r25z 3 Ma"

RO" and Ma»b5 - ROB Coma"

Be?" iMa»b5 - Be5 in 2Ma"

At the same time, impurities of heavy metals are completely precipitated.

Reactions of neutralization of the electrolyte and precipitation of heavy metals in order to intensify them and ensure uniformity are carried out while stirring the solution.

The claimed method is carried out as follows.

Spent electrolyte of lead-acid batteries and sodium solution of the vacuum-carbonate coke gas cleaning plant are metered into a hermetically sealed container equipped with: fittings for supplying reacting solutions, draining the solution, draining the settled sludge, suctioning reaction gases, a stirrer (see fig.) from hydrogen sulfide in the amount of 595 wt. more than is needed to carry out the neutralization reaction of the spent electrolyte. This mixture is mixed in a container. During this time, the main neutralization reactions of the spent electrolyte take place. Then the 2956th sodium sulfide solution (Ma25) is fed into the container in a ratio of 2:11 (2 mass parts of the neutralized solution and 1 mass part of the 295 sodium sulfide solution), the solution is mixed, gases (He, СО», 50», Nab5), formed in the processes of neutralization reactions and precipitation reactions of heavy metals, were constantly sucked from the tank and fed into the coke gas purification system at the coke chemical plant. After standing in the container, the solution is separated into a liquid and pulp sediment.

The liquid through the drain fitting is fed into the phenolic effluents of the coke chemical plant for further use. Pulp sludge is drained and sent for additional processing in the technological process of processing scrap batteries.

For the implementation of this method of neutralization of the spent electrolyte of lead-acid batteries, the use of coke-chemical production infrastructure is currently the most optimal, since the spent electrolyte is completely neutralized with the soda solution of vacuum carbonate desulfurization, which is a waste in coke-chemical production, the solution formed after neutralization of the electrolyte and of precipitated heavy metals is diverted to the phenolic effluents of coke-chemical production for further use, and only the pulp sediment of heavy metals is transferred to a new technological process - processing of non-ferrous metal scrap.

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E nin shko : and I in | Here are some necks Ek EV Z Ii busyutsy spa

LI sh in VZHK Wed nnvaonnntfagy 1 Zlyv shomu ; and Fozhyun of metals

Fig.

Claims (1)

The method of disposal of the electrolyte of used lead-acid batteries, which consists in the neutralization of the electrolyte and the precipitation of heavy metals from it, which is distinguished by the fact that the method is implemented in the infrastructure of a coke-chemical plant, where the neutralization of the electrolyte is carried out with the spent soda solution of the vacuum-carbonate desulfurization shop from hydrogen sulfide during its mixing , while the amount of soda solution is determined according to the reaction of neutralization of sulfuric acid of the electrolyte with the addition of another 595 wt; the metals contained in the neutralized solution are precipitated by adding to it 295 sodium sulfide solution in a 2:1 ratio (2 parts by weight of the neutralized solution to 1 part of the 295 sodium sulfide solution), the resulting solution is transferred to the existing phenolic effluents of the coke chemical plant, the pulp of precipitated of metals is merged for further processing, gases formed in the process of neutralization of the electrolyte and in the process of precipitation of metals are constantly sucked into the existing coke gas purification system.