SU1738756A1 - Method of recovering non-ferrous metals from salt solutions using adsorption - Google Patents

Abstract

The invention relates to methods for sorption extraction of non-ferrous metals from solutions of a complex composition with different salinity, such as sea water and brines, and allows an increase in the degree of extraction. The method of sorption extraction of non-ferrous metals from salt solutions of a complex composition consists in passing an initial solution through a low-base anion exchange resin followed by desorption of non-ferrous metals with a dilute acid solution, using epoxy-amine anion exchanger as a low-base anion exchange resin, periodically processing the latter with 0.1-1 M solution in the amount of 10-3 beats about. respectively. The treatment of the anion exchanger is carried out after saturation with boron. 1 з п. Ф-лы, 3 il., 2 tabl. SO with

Description

The invention relates to methods for sorption extraction of non-ferrous metals and can be used in sorption extraction from solutions of complex composition with different salinity, such as sea water and brines.

The known methods of extracting non-ferrous metals from a saline solution (sea water) are carried out by sorption on ionites of various classes: cation exchangers, anion exchangers, ampholytes, chelate sorbents. The most promising for the recovery of non-ferrous metals from seawater are polyampholytes and chelate sorbents; their distribution coefficients on these sorbents reach values higher than 105.

However, the difficulty of desorption of non-ferrous metals from them and the lack of industrial output limits the use of these sorbents in the framework of the concentration of non-ferrous metals with the help of analytical determination. Selective cation exchangers were not widely used for the recovery of non-ferrous metals from seawater.

The closest technical solution to the present invention is a method for sorption extraction of non-ferrous metals from salt solutions of a complex composition, which consists in passing an initial solution through a slightly basic anion exchange resin AN-31 followed by desorption of non-ferrous metals with a diluted 0.5 M hydrochloric acid solution.

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The method allows the extraction of non-ferrous and other valuable metals from seawater in plants of various types. The method allows to achieve the degree of concentration of a (a is the ratio of the concentration of metal in the regeneration solution to its content in the source water) for copper, nickel and zinc, respectively equal to 10, 4-102, 1.5-102. is 3.6 10 ml / g.

The disadvantage of this method is the low values of sorbed metals and their low concentration in the regeneration solution. Thus, the concentration of copper in the ion exchanger is equal to 4.9 mg / l, and in the regeneration solution - 0.4 mg / l. Thus, despite the relatively high selectivity of the ion exchanger and the degree of concentration of the metals, the method is practically inapplicable to the problem of extracting non-ferrous metals, further concentration is required.

The aim of the invention is to increase the recovery rate of non-ferrous metals.

This goal is achieved in that according to the method of sorption extraction of non-ferrous metals from a salt solution of a complex composition consisting in passing the initial solution through a low-base anion exchange resin followed by desorption of non-ferrous metals with a dilute acid solution, an epoxy-amine type anion exchange resin is used as a low base anion exchange resin. with a solution of alkali 0.1-1.0 M in a volume of 3-10 ud.ob. Moreover, the processing of anion exchange resin is carried out after saturation with boron.

The use of an alkali concentration below 0.1 M is inefficient, since it leads to an increase in the time of sorbent conversion to the hydroxyl form, which is necessary for further carrying out the process of sorption of non-ferrous metals, and, in addition, boron desorption is difficult.

The use of a solution of alkali concentration above 1 M leads to unreasonable costs of the reagent.

FIG. 1 shows the dependence of the sorbed amount of metal on the missed volume of water (a is sorption, µg / g; V is water volume, m; copper; x is nickel); in fig. 2 - pH dependence of the water leaving the column on the time of sorption, t; in fig. 3 - curves of desorption of metals from anion exchanger SB- 1 with 0.5 M hydrochloric acid solution (с - concentration, mg / l, q - specific volume of hydrochloric acid; - copper; h - nickel).

Anionit SB-1 is synthesized in the form of spherical particles of gel structure, possessing satisfactory thermal stability and chemical

resilience. The anion exchanger contains amino groups of all basicities, and in addition, it contains aminooxyethyl groups selective for boron (previously, the anion exchanger SB-1 was used to extract boron from sea water).

When studying the sorption properties of SB-1, it was found that sorption of non-ferrous metals occurs along with boron, and their accumulation from cycle to cycle.

5 Thus, 130 is absorbed in one cycle, and 1650 µg / g of copper during eleven, which is 0.06 and 0.7% of the total exchange capacity of the anion exchanger, respectively. Accumulation in 11 cycles the amount of copper

0 (1650 µg / g) corresponds to a distribution coefficient of 2.4-10 ml / g at a copper concentration of 7 µg / l in seawater, and (Fig. 1) is not the limit: the dependence of the sorption amount

5 of the volume of water missed represents a straight line. This value is comparable to the copper distribution coefficients obtained for Polioorgs XII and Mthilon-T, highly selective fibrous ion exchangers.

0 However, desorption of non-ferrous metals from these sorbents is difficult.

Large amounts of copper sorbed by the anion exchange resin in the indicated mode with periodic treatment with sodium hydroxide,

5 due to the specificity of the process of sorption of non-ferrous metals in alkaline media. After boron desorption with a 0.1 M solution of NaOH, the pH of the water leaving the column rises to 8.5 and exceeds the pH of sea water, equal to 8.25, during the entire cycle of boron sorption (Fig. 2). Under these conditions, the sorption of metals is carried out mainly due to the formation in the phase of the sorbent of hydroxo complexes of the type (Cu (NH2)

5 (OHZ) and metal hydroxides.

The complete desorption of non-ferrous metals with SB-1 is carried out with a solution of 0.5 M hydrochloric acid. When treating an ion exchanger with a 0.1-1.0 M solution of NaOH, no

0 more than 5% of sorbed non-ferrous metals.

The proposed method of extracting non-ferrous metals with anion exchanger SB-1 in hydroxyl form can be carried out as in

5 static and dynamic conditions, Example 1. The sorption test was carried out under static conditions from a model solution of sea water with a copper concentration of 15 mg / l and a pH of the initial solution equal to 6. The sorption of copper was carried out at a constant

stirring 0.1 g of crushed ion exchanger with 200 ml of solution for 24 hours. Then the sorbent is separated from the solution, washed with 10 ml of 0.1 M sodium hydroxide solution (elution of boron), 5 ml of distilled water. In the next sorption cycle, the ion exchanger is filled with a new portion of the solution. The sorption process, followed by treatment of the ion exchanger with a solution of NaOH, is repeated many times. In the control experiment, after sorption, the ion exchanger SB-1 is not treated with sodium hydroxide. The copper content in the solution is determined by atomic absorption spectrometry with flame atomization (AAS with PA). The copper content in the ion exchanger is calculated from the difference in copper concentrations in the initial and equilibrium solutions. After five cycles of sorption, the content of copper in the ion exchanger is 148 mg / g (64% of the total exchange capacity). During periodic treatment of the anion exchanger with a 0.1 M solution of sodium hydroxide, the complete extraction of copper by the anion exchanger from the model solution of seawater occurs. After three cycles of sorption, the content of copper in the ion exchanger in the control experiment was 70 mg / g (30% of the total exchange capacity), after the fourth cycle, 72 mg / g, i.e. after three cycles, the capacity of the ion exchanger increases slightly.

Example 2. Experiments on sorption of non-ferrous metals from natural seawater were carried out under dynamic conditions on a column with a cross section of 63 cm (weight 25-50 g, layer height 1.5-2 cm, consumption of seawater 0.5 m3 / h).

The conditions of the experiments and the results of sorption of ferrous metals are given in Table. 1: in experiments 1 and 2, carried out on a seawater simulator prepared by dilution of brine, sorption was carried out on anionites SB-1 and AN-31; in experiment 3, sorption of metals was carried out using anion exchanger SB-1 from ocean water. The metal content in the ion exchanger was determined by atomic absorption spectrometry with laser atomization of AAS with LA, and was also calculated from the desorption of metals with a 0.5N hydrochloric acid solution using the AAS method with PA.

From the data table. Figure 1 shows that a higher concentration of non-ferrous metals was obtained on the SB-1 anionite, than on the AN-31, under identical conditions of the experiment. Particularly high concentrations of non-ferrous metals were obtained in samples of SB-1, spent on ocean water (experiment 3), which is associated with a higher concentration of non-ferrous metals, in particular copper, in water of 7.3 µg / l, compared with the concentration in water Black Sea 2 µg / l. The recovery of copper in Test 3 is 40%.

From tab. 1 that when processing the spent ion exchanger with 1 M NaOH solution

the concentration of non-ferrous metals in the ion exchanger is reduced by no more than 5%, and when the same ionite sample is processed with a 0.5 M solution of hydrochloric acid, non-ferrous metals are desorbed to the level of

their content in the blank sample.

Example 3. Sorption of non-ferrous metals from ocean water is carried out on a column with a section of 120 cm2 (ionite volume 1.35 l, layer height 11 cm, sea water consumption 0.5

m3 / h, sorption time 8-10 h). After sorption, the ion exchanger is washed with 2 liters of tap water, then it is treated to desorb boron with 15 liters of 0.1 M sodium hydroxide solution. In this case, the anion exchange resin goes into hydroxyl

form (control is carried out by titration of the alkali solution). Before each new sorption cycle, the ion exchanger is washed out of suspension and loosened with a countercurrent of seawater. After several cycles taken with

using countercurrent ion exchanger for analysis. The metal content in the sorbent is determined by the AAS method with LA. The results are shown in Table. 2 (mass of ion exchanger 280 g).

As can be seen from the table. 2, carrying out the process of extracting metals under dynamic conditions with the intermediate treatment of an anion exchanger with 0.1 M sodium hydroxide solution promotes the accumulation of non-ferrous metals.

fishing in the ionite. With an increase in the number of cycles, the amount of sorbed metals increases, the degree of copper recovery in this case is 85-73%. At the same time, manganese accumulation practically does not occur. Such

The difference in metal sorption can be explained by another manganese sorption mechanism, for which the pH of hydroxide precipitation (pH 9) is significantly higher than that of non-ferrous metals (pH 5-7.5). The desorption of non-ferrous metals from an anion exchanger is carried out with 12 liters of a 0.5 M hydrochloric acid solution, at a flow rate of 3 l / h. After 8 cycles, the concentration of nickel and copper in the eluate reaches 30 and 60 mg / l, respectively (Fig. 3). The degree of copper concentration in this case is 8.5-103.

Thus, the proposed method allows to obtain high values of the capacity of non-ferrous metals while extracting them.

from solutions like seawater due to the use of anion exchanger SB-1 in hydroxyl form with a treatment with its 0.1 M sodium hydroxide solution between sorption cycles.

Claims (2)

Claim 1. A method for sorption extraction of non-ferrous metals from salt solutions, which involves the transmission of an initial solution through a low-base anion exchange resin followed by desorption of non-ferrous metals with a dilute acid solution, which is characterized by the fact that low-base anion exchange resin using an epoxy-amine type anion exchange resin with periodic treatment of the latter with a solution of alkali with a concentration of 0.1-1 M in a volume of 10-Itch. respectively. 2. A method according to claim 1, characterized in that the treatment of the anion exchange resin is carried out after saturation with boron. Table 1 table 2 about. ttt ISM thirty at 10 FIG. 2 t 20 WITH IN BO 20 x / 1I 50 245 V Fig.Z