RU2259952C1 - Method of separation of $$$ ions from processing solutions - Google Patents

Abstract

FIELD: cleaning waste water and processing solutions by ionites; selective sorption of ions of transition metals for separation of them.

SUBSTANCE: extraction of copper ions Cu²⁺ from processing solutions is performed by passing the solutions through charge of low-basic amine-containing anionite; used as sorbent is sludge of ionites from Duolite A365, Duolite A7 and Purolite A109 series. Then, reduction of ions of Cu²⁺ to metal is performed in anionite phase. Sorption-reduction cycles are repeated many times and anionite is washed with water after each reduction stage for removal of alkali. Alkaline solutions of sodium dithionite or hydrozine sulfate may be used as reductants; reduction may be performed by low-density electric current. Proposed method ensures regeneration of saturated complex-forming sorbent without separation of component being sorbed from polymer phase.

EFFECT: enhanced efficiency of copper concentration.

4 cl, 1 tbl, 3 ex

Description

The invention relates to the treatment of wastewater and technological solutions with ion exchangers, and can find application in the technology of processes of selective sorption of transition metal ions in order to separate them, as the possibility of rational use of the sorbent material.

It is known that during the separation of ions with different adsorbability on a fixed layer of a complexing sorbent, the latter, as a result of its full saturation with the most active complexing ion, is subject to regeneration by the destruction of the ionite complex with subsequent desorption of this ion and further operation of the resin. Thus, concentration and isolation of this component is achieved [1-6].

A known method for the extraction of non-ferrous metal ions (including Cu ²⁺ ) from various solutions of complex composition (sea water, brines, etc.), followed by elution of the absorbed ions with a 0.5 M HCl solution [3].

A highly selective method is known for the extraction of Cu ²⁺ from solutions using a sorbent, which is the product of the interaction of secondary polyethylene and the oligomer of di- (β-methacryloyl-α-chloromethyl) methylphosphonate.

The closest to the invention in chemical essence is a method for the extraction of Cu ²⁺ from acidic weakly concentrated wastewater using a polyethylene polyamine sorbent, which, like all of the above, involves the regeneration of the sorbent by desorption of the absorbed ions after saturation by treating it with a suitable reagent, converting the sorbent back into its active form , as well as obtaining a more or less concentrated eluate to be further processed in order to isolate the metal [5]. The disadvantage of this method of regeneration, in some cases, is the lack of concentrability of the extracted component.

The objective of the invention is to develop a method for the regeneration of a saturated complexing sorbent without isolating the adsorbed component from the polymer phase, which is more effective concentration.

This can be achieved by the fact that in the known method for the separation of Cu ²⁺ copper ^ions from wastewater or technological solutions by passing the solution through the loading of a low basic amine-containing anion exchange resin, Duolite A365 sludge (aminated styrene-divinylbenzene copolymer), Duolite A7, is used as a sorbent. (phenol-formaldehyde polycondensate, secondary amino groups, production of ROHM & HAAS, USA), Purolite A 109 (macroporous styrene-divinylbenzene copolymer, primary amino groups, production of PUROLITE, USA) reduce ions copper Cu ²⁺ in the anion-exchange phase to the metal, sorption-reduction cycles are carried out repeatedly, and after each reduction step, the metallized sorbent is washed with water. As a reducing agent, alkaline solutions of sodium dithionite or hydrazine sulfate are used. Possible restoration of low density electric current. Thus, Cu ^{2+ is} converted into a coordinately inactive form.

The most convenient is the process of concentrating copper in the polymer phase in a dynamic mode, i.e. in a column reactor filled with resin. A saturating solution containing Cu ²⁺ is passed through the column at low speeds until the anionite is completely saturated. The resulting anionic amine complex Cu must be reduced to a metallized polymer, which is again capable of complexation with Cu ²⁺ . As a result of successive repeated repetition of saturation-reduction operations, a polymer with a significant proportion of metallic copper is obtained.

Example 1. In order to isolate and concentrate Cu ²⁺ from a highly diluted solution (~ 1.5 mmol / dm ³ , 96 mg / dm ³ ) containing a comparable concentration of Zn ²⁺ (~ 1.0 mmol / dm) (i.e. ., for example, like washing water from brass production) or other cations, which have the stability constants of amino complexes by orders of magnitude lower than for Cu ²⁺ , it is passed with low linear speeds (0.2-0.5 m / h: speeds less than 0 , 2 m / h are impractical due to the duration of the resin saturation process (up to several days at a loading column height of several cm) due to small concentrations of Cu ²⁺ , speeds greater than 0.5 m / h lead to a decrease in the degree of extraction of Cu ²⁺ to 50% or less) through a column loading low-basic anion exchange resin from the series Duolite A365, Duolite A7, Purolite A109 (2 cm was taken for the experiment ³ , the column diameter is 7 mm) until the resin sample is completely saturated with Cu ^{2+ ions} (photocolorimetric control of the Cu ²⁺ concentration at the outlet). In this case, Zn ²⁺ is quantitatively displaced by Cu ^{2+ ions} into the filtrate, which can be further processed in a similar way to extract the remaining Cu ²⁺ . The resulting ionite complex is chemically reduced to Cu ^{2+ with an} alkaline aqueous solution of sodium dithionite: 2.5% NaOH, 6% Na ₂ S ₂ O ₄ ). The result is a metallized polymer, again capable of complexation. With repeated repetition of sorption-reduction cycles, the mass fraction of metallic copper in a metallized anionite sample can reach ~ 50%. After each stage of recovery, a sample is washed with distilled water from an excess of the corresponding alkali to a negative sample (a sample for dithionite is optional, washing should be carried out before the neutral reaction of running water at the column outlet (phenolphthalein); a sample for non-absorbed Cu ^{2+ ions is} also optional the reason for the smallness of their concentration).

Example 2. In order to isolate and concentrate Cu ²⁺ from highly diluted solutions as a sorbent, m. applied anion exchange resin from the series Duolite A365, Duolite A7, Purolite A109 (loading volume 2 cm ³ ), which is saturated with Cu ^{2+ ions} as in Example 1. Cu ²⁺ is reduced with an alkaline aqueous solution of hydrazine sulfate (6% hydrazine sulfate + sodium hydroxide until neutralization + 2.5% sodium hydroxide in excess of this amount).

Example 3. Anion exchange resin from the series Duolite A365, Duolite A7, Purolite A109 (loading volume 2 cm ³ ) is saturated with Cu ^{2+ ions} as in examples 1, 2. The reduction of Cu ^{2+ is} carried out by low-density electric currents (0.5-1.0 A / dm ² ).

Copper can be extracted from the anionite phase after a significant decrease in its sorption ability by oxidation with nitric acid (dilution 1:10) or by burning the resin at a temperature of 1000-1100 ° С, which ensures maximum concentration of the extracted copper (in the first case, acidic concentrates up to 40 g / l, in the second - almost pure metallic copper).

The specific capacities of the anionite samples E _i , meq / cm ³ (mg / cm ³ ), for Cu ²⁺ depending on the number of the saturation-reduction cycle i and the total capacity Σ (E _i ) of three cycles as the experimental results are shown in the table. The lack of correlation between the capacitance values is due to the qualitative difference between the free and metallized polymer as a sorbent.

Table
The method of separation of Cu ^{2+ ions} from technological solutions Purolite A109 Duolite A7 Duolite A365 E ₁ 1.190 (38.08) 0.875 (28.0) 1,200 (38,40) E ₂ 1.470 (47.04) 1.440 (46.08) 1.500 (48.0) E ₃ 0.460 (14.72) 1.440 (46.08) 2.200 (70.40) Σ (E _i ) 3.120 (99.84) 3.755 (120.16) 4.900 (156.80)

Sources of information

1. The method of purification of solutions of ferric ions. USSR copyright certificate No. 1159895, class C 02 F 1/42. 1985.

2. The method of extraction of Nickel from the wash water of galvanic industries. USSR copyright certificate No. 1643466, cl. C 02 F 1/42. 1991.

3. The method of sorption extraction of non-ferrous metals from salt solutions. USSR copyright certificate No. 1738756, cl. C 02 F 1/42. 1992.

4. A method for extracting copper from a solution. USSR copyright certificate No. 1692947, cl. C 02 F 1/42, 1/28; C 01 C 3/00; B 01 J 20/26. 1991.

5. The method of extraction of copper salts and acids from weakly concentrated wastewater. USSR copyright certificate No. 789404, cl. C 02 F 1/42, B 01 D 15/04. 1980. (prototype)

6. Ion exchange separation in analytical chemistry. O. Samuelson. Ed. "Chemistry". 1966. Art. "Chelated ion exchangers", p.115.

Claims (4)

1. The method of separation of copper ions of Cu ²⁺ from technological solutions by passing the solution through a load of low-basic amino-containing anion exchange resin, characterized in that sludge use ion exchange sludge from the series Duolite A365, Duolite A7, Purolite A109, restore Cu ²⁺ in the anion exchange phase to metal, and sorption-reduction cycles are carried out repeatedly with washing of the anion exchange resin with water after each stage of recovery. 2. The method according to claim 1, characterized in that the alkaline aqueous solution of sodium dithionite is used as a reducing agent: 2.5% NaOH, 6% Na ₂ S ₂ O ₄ . 3. The method according to claim 1, characterized in that as the reducing agent use an alkaline solution of hydrazine sulfate: 6% (N ₂ H ₅ ) ₂ SO ₄ + NaOH to neutralize + 2.5% NaOH. 4. The method according to claim 1, characterized in that the recovery of Cu ^{2+ ions is} carried out by low density electric currents of 0.5-1.0 A / dm ² .