SU1493692A1 - Method of chemical regeneration of spent electroplating solutions - Google Patents

Abstract

The invention relates to the field of chemical regeneration of spent electroplating solutions contaminated with iron. The aim of the invention is to increase the degree of purification of the solution from iron and simplify the process. The method consists in the continuous selection of the spent electroplating solution into the reactor, its treatment with atmospheric oxygen in the presence of a catalyst, which is a finely dispersed magnetite with a mass ratio of magnetite to iron (3-5): 1. Oxidation of iron (A) to iron (III) is accompanied by the formation of a precipitate of iron hydroxide (III), which is removed using magnetic filters. The iron content in the spent solution is 30 mg / l. The treatment time of the solution is 6 minutes, and the iron content in the regenerated solution is trace. Using this method allows to achieve a high degree of solution purification from iron with sufficient simplicity of its implementation. 1 il. 2 tab.

Description

one

(2J) 4284890 / 23-02

(22) 07/14/87

(46) 07.15.89. Bul No. 26

(72) V.L. Mikhailovsky, V.E. Ternovtsev, R.M. Dovgan, L.N. Okrug

and V. P, Dubrovsky

(53) 621.357.004.86 (088.8) (56) French Application No. 2520007, cl. C 23 C 1/00, 1983.

Austrian patent number 319897, cl. 12 May 34/06, 1975.

(54) METHOD FOR CHEMICAL REGENERATION OF SPREADED GALVANIC SOLUTIONS (57) The invention relates to the field of chemical regeneration of spent electroplating solutions contaminated with iron. The aim of the invention is to increase the degree of purification of the solution from iron and simplify the process.

The method consists in the continuous selection of spent electroplating. the solution into the reactor, its treatment with oxygen in the presence of a catalyst, which is finely dispersed magnetite with a mass ratio of magnetite to iron (3-5): 1. The oxidation of iron (II) to iron (III) is accompanied by the formation of a precipitate of iron (III) hydroxide, which is removed with the aid of magnetic filters. The iron content in the spent solution is 30 mg / l. The solution processing burden is 6 minutes, and the iron content in the regenerated solution is trace. Using this method allows to achieve a high degree of solution purification from iron with sufficient simplicity of its implementation. 2 tab.

(L

The invention relates to the chemical regeneration of spent electroplating solutions contaminated with iron.

The purpose of the invention is to increase the degree of purification of the solution from iron and simplify the process.

The essence of the invention lies in the fact that the spent galvanic solution contaminated with iron is continuously taken to the reactor. They are bathed with oxygen in the presence of a catalyst, for which fine-grained magnetite is used with a weight ratio of magnetite to iron (3-5): 1. Here, iron (II) is converted into iron (III).

to form a precipitate of iron (III) hydroxide, which is removed by filtering the solution using magnetic filters.

Carrying out the oxidation process in the presence of finely dispersed magnetite increases the rate of oxidation of iron (II) to iron (III), eliminates the dilution of the solution and reduces the volume of iron (III) hydroxide precipitate.

When the ratio of the mass of the fine powder of ferromagnetic material to the mass of the removed iron is less than 3: 1, the residual iron content in pereHepii sharply increases.

WITH

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After removal of the siege of iron (III) hydroxide, and when the ratio exceeds 5: 1, the specific volume of sludge increases without an account of the quality of purification.

Example 1, Spent galvanic solution of the following composition; cadmium ferrous acid 50 g / l; ammonium sulfate 32 g / l; sulfuric acid (25 ml / l); gelatin 0.6 g / l; Geozo 30 mg / l, from the process bath is fed to the reactor-oxidizer. Simultaneously, an agnetite with a particle size of 50–100 µm is fed from the bunker to the reactor, 15 for received after the enrichment of the iron; The dose of magnetite is set at 1200 g / l or 40 mg of magnetite per 1 mg of iron (III). Complete iron oxidation

(II) provide air supply from 20 polu 111 of the distributor 5 in the amount of 8.6 l per 1 mg of iron (II). The process time is 25 minutes. Processed electroplating solution

together with iron hydroxide precipitate 25

(III) on a ferromagnetic fine dispersion, is fed to the loading of a magnetic flux line, where the solution is clarified. We regenerate the 1st solution which has the following composition: sulfuric acid cadmium30 50 g / l; sulfuric acid amygany 32 g / l; sulfuric acid} ominium 25 g / l; gelatin

O, 0.6 g / l; total iron 0.8 mg / l.

A higher dose of magnetite obtained from enriched pv; yes, less than 35 mg of pa 1 mg of iron (II) causes not all of iron (III) to be agglomerated with magnetite, and part of iron (III) and ipde hydroxide at Filtrod.ishi passes through magneti- 40 important zlgruzky not delayed.

The volume of sediment (after settling for 2 hours) in suspension, taken after the reaction of the reactor before filtration, will be 13.5% of the total volume. 45

Example 2. A solution having the same composition as in example 1, is fed into the reactor-oxidant, blown with air and at the same time serves finely dispersed magnetite obtained CQ from iron-containing solutions by chemical condensation, with a particle size of 0.3-0.4 um Dose of magnetite - 2 mg per 1 mg of iron (II), Air is supplied and the calculation is 2 liters of air per 1 mg j, iron (II) for 6 minutes “Coathe-t / aci of iron (II) after 2, 4 and 6 minutes will be respectively 5, I and 0.2 mg / l. The volume of sediment after settling is not

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6 m;

ta ack du ne ng not and ce

those about fi tse so

ta pr du ma ma 5 co c h al n i 1, ro ko te

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20 25

- thirty

35 40

45

CQ j,

Stabilization for 2 hours will be 3.2% of the sample volume. The solution is passed through a magnetic filter. The filter is contaminated with the colloidal iron (III) phase with a concentration of 12 mg / l.

Example 3. A solution having the same composition as in example 1 is fed to the oxidizer reactor, purged with air as in example 2, and one; At present, finely dispersed magnetite is supplied (of the same type as in Example 2). The dose of magnetite is 3 mg per 1 mg of iron (II). The concentration of jelly (III) in the solution after 2, 4 and 6 minutes is 4; 0.7 and 0.1 mg / l. The volume of sediment after settling for 2 hours was 2.5% of the total volume. The solution from the oxidizing reactor is fed to a magnetic filter. The filtrate is contaminated with the colloidal phase of iron (III) at a concentration of 2.5 mg / l.

Example 4 A solution having the same composition as in Example 1 is fed from technical vanilla to an oxidizing reactor, purged with air, and at the same time finely dispersed magnetite is fed at the rate of 4 mg of magnetite per 1 mg of iron (II). The type of magnetite and air consumption are the same as in example 2. After 2 and 4 minutes, the concentration of iron (II) in the solution will be 3 and 0.3 mg / l, respectively, and after 6 minutes, traces of iron (II) are fixed in the solution.

The volume of sediment after settling for 2 hours is 1.1% of the total sample volume. The solution from the reactor is filtered on a magnetic fkptre. The concentration of iron (III) in the filtrate will be 0.1 mg / l.

Example 5. A solution having the same composition as in Example 1 is purged with air in an oxidizing reactor and simultaneously fed into it. magnetite, as in example 2. The dose of magnetite is set at the rate of 5 mg of magnetite per 1 mg of iron (II). The concentration of iron (II) in the solution after 2 and 4 minutes will be 2.0 and 0.1 mg / l, respectively, and after 6 minutes - traces. The volume of sediment after solution retention (within 2 hours) will be 1.2% of volume: about volume. After filtering the solution on a magnetic filter, the concentration of iron (II) in the fcptrate is traces,

Claims (2)

Example 6 A solution having the same composition as in the example is deposited on magnetite and which is easily removed from the solution by filtration using magnetic filters, which results in a high degree of purification of the electroplating solution from iron. In addition, this method is much simpler to implement, in particular, it does not require special equipment for carrying out the process at elevated temperatures and pressures, as in prototype D. Invention Formula Method for chemical regeneration of spent electroplating solutions Magnetite after ovocatene iron ore of the Krnvvorak basin This method of magnetite obtained by E9 iron-containing solutions by the method of chemical condensation . - - 40: 1 2: 1 | 1 eleven contaminated with iron, which includes taking the solution into the reactor, treating it with oxygen in the presence of a catalyst, as oxides take iron oxides to convert iron (II) to iron (III) to form a precipitate, then removing the precipitate by filtration, that, in order to increase the degree of purification of the solution from iron and simplify the process, finely dispersed magnetite is introduced as iron oxides with a mass ratio of magnetite to iron ions (3-5): 1, and filtration is carried out using magnetic filters. I Table I Note 13.5 25. Next 0.8 2 A 6 5.0 1.0 0.2 12.0 11 5U9 re 1, serves air and magnetite at the rate of 6 mg of magnetite per 1 mg of iron (II). Air consumption and type of magnetite are the same as in examples 1-5. The concentration of iron (II) in the solution after 2, 4, 6 minutes will be 2.5; 1.0 and 0.2 mg / l. The volume of sediment after settling the solution for 2 hours will amount to 2.4% of the total volume. The solution from the reactor is fed to a magnetic filter. The concentration of iron (II) in the filtrate is trace. Example 7. The solution, the same composition as in example I, is fed to the reactor-oxidant and air is blown in the same way as in example 2. The concentration of iron (II) in the solution after 10, 20 and 30 minutes takes the following values 15, 6 and 2 mg / l with the amount of inhibited air per 1 mg of iron (II) 12, 24 and 36 liters, respectively. After compaction, the sediment volume was 8% of the volume of the solution. After that, finely dispersed magnetite powder of the same type as in Example 2 is added to the solution at the rate of 4 mg of magnetite per 2 mg of iron and phi rub; in the filtrate - 4 mg / l Fe (III). 30 times the volume of solution lost A sample is taken from the reactor and settled for 2 hours. The volume of sediment will be 7.2%. Thus, the addition of magnetite after completing the formation of iron (II) hydroxide does not change the volume of the precipitate. The results obtained in examples 1-7 are presented in table. one. As can be seen from the above examples 1-7, the optimal material dp for regenerating the solution according to the proposed method is finely dispersed magnetite with a particle size of 0.3-0.4 µm, obtained from iron-containing solutions by chemical condensation. The use of magnetite after the enrichment of iron ore having particle sizes of about 50-100 microns, causes an increase in its dose to 40 mg per 1 mg of iron (II) due to the fact that such magnetite has a small specific surface area. Fine-grained magnetite exhibits the properties of an effective catapisator. At the same time, the dose of magnetite has no significant effect on the catalytic effect. So in the case of the ratio of Ge04: Ee (II) 2 and D, 04: 6 : Fe (II) 5 after 4 minutes of oxidation by air oxygen, the oxidation effect of iron (II) exceeded 97%, while, when treated with air without magnetite, the oxidation effect was about 50% (Example 7). However, the magnetite coking quality is crucial for determining the residual content of the colloidal iron (III) phase, contaminating the filtrate after filtration and, therefore, reducing the quality of the cleaning of the electroplating solution from iron. As 5 can be seen from the table. I, when the ratio of the mass of magnetite to the mass of iron (III) is within (3-5): 1, the residual amount of the colloidal phase of iron (III) in the filtrate is small and ensures a satisfactory cleaning quality of the electroplating solution from iron, when this ratio is less than than 3: 1, the amount of iron in the filtrate increases significantly, with more than n - 5 times the magnetite content in relation to the iron content in the solution, the iron removal efficiency does not change, however, the volume of sediment increases and, accordingly, increases sediment. When magnetite is added after aeration, a decrease in the efficiency of regeneration is observed, since flake iron (III) hydroxide in the form of Fe (OH) has already been formed and the process of diffusion of magnetite particles into the volume of the formed aggregates of iron (III) hydroxide is very difficult. therefore 0, the specific volume of the oxide in this sequence of implementation of the method is more than 2 times greater than the volume of sediment obtained in examples 4 and 6, as shown by experimental c data, the best parameters of the regeneration process ensure the use of finely dispersed magnetite at a dose of 4 mg of magnetite per 1 mg of iron (II). The main technical parameters of the regeneration process are given in table. 2 Unlike the prototype, when using which the main part of oxidized iron (III) is obtained in the dissolved state in the form of FeClj in — in this method, almost all oxidized iron (III) is precipitated in the form of hydroxide Pe (OH) 3, which five Process parameters Processing time, h: in solution ia filter Co-concentration of iron (RB) in the regeneration solution, mg / l O volume of sediment,% of the total volume of the solution after a single regeneration Volume of the solution lost after a single regeneration,. from the initial volume Dilution of the solution due to liquid reagents, 7. after ten times regeneration 1493692 Table ten I Process results