Method for the Elution of Aluminum Ions and/or Zinc Ions

Abstract

The present invention relates to a method for the elution of aluminum ions and/or zinc ions of polymers containing aminomethylphosphonic acid groups.

Claims

1. A process for elution of aluminum ions and/or zinc ions, comprising the steps of admixing an aminomethylphosphonic acid group-containing polymer, or a salt thereof, at least partially laden with aluminum ions and/or zinc ions with a base selected from the group of consisting of alkali metal hydroxides, ammonium hydroxide, and mixtures thereof; and eluting the aluminum ions and/or zinc ions with a solution.

2. The process as claimed in claim 1, wherein aminomethylphosphonic acid group-containing polystyrene-divinylbenzene copolymers are used as the aminomethylphosphonic acid group-containing polymers.

3. The process as claimed in claim 1, wherein average degree of substitution of the aminomethyl groups by phosphonic acid groups in the aminomethylphosphonic acid group-containing polymers is 1.4 to 2.0.

4. The process as claimed in claim 1, wherein the base does not contain any potassium oxalate.

5. The process as claimed in claim 1, wherein particles of the polymer have a diameter (d.sub.50) of 250 m to 450 m.

6. The process as claimed in claim 5, wherein at least 90% by volume or 90% by mass of the particles have a diameter within the interval of 10% of the most common diameter.

7. The process as claimed in claim 1, wherein the eluting solution is an aqueous 6% by weight-12% by weight alkali metal hydroxide solution.

8. The process as claimed in claim 1, wherein aluminum ions are eluted.

9. The process as claimed in claim 1, wherein the aminomethylphosphonic acid group-containing polymer is a chelating resin containing functional groups of structural element (I) ##STR00003## in which is a polystyrene copolymer skeleton and R.sup.1 and R.sup.2 may be identical or different and are independently CH.sub.2PO(OX.sup.1).sub.2 and CH.sub.2PO(OH)OX.sup.2 or hydrogen, where R.sup.1 and R.sup.2 may not both simultaneously be hydrogen and X.sup.1 and X.sup.2 are independently hydrogen, sodium, potassium or lithium.

10. A process for elution of aluminum ions and/or zinc ions, comprising the steps of, a.) bringing into contact with an aqueous metal ion solution containing aluminum ions and/or zinc ions and optionally further metal ions, at least one chelating resin containing functional groups of structural element (I) ##STR00004## in which is the polystyrene copolymer skeleton and where R.sup.1 and R.sup.2 may not both simultaneously be hydrogen and X.sup.1 and X.sup.2 are independently hydrogen, sodium, potassium or lithium; and b.) eluting the aluminum ions and/or zinc ions with an aqueous alkali metal hydroxide solution or/and an ammonium hydroxide solution.

11. The process as claimed in claim 10, wherein R.sup.1 and R.sup.2 may be identical or different and independently are CH.sub.2PO(OX.sup.1).sub.2 and CH.sub.2PO(OH)OX.sup.2.

12. The process as claimed in claim 11, wherein X.sup.1 and X.sup.2=H.

13. The process as claimed in claim 10, wherein the aqueous metal ion solution contains aluminum ions, nickel ions and cobalt ions.

14. The process as claimed in claim 13, wherein the molar ratio of the aluminum ions to the nickel ions and the cobalt ions is 0.5 to 1.5.

15. The process as claimed in claim 10, wherein the aqueous metal ion solution has a pH of 1.5 to 6.0.

Description

EXAMPLES

Example 1

A. Loading of a Macroporous, Monodisperse Chelating Resin Containing Functional Groups of Structural Element (I) with Aluminum, Nickel and Cobalt

[0074] 200 ml of the chelating resins containing functional groups of structural element (I) where R.sup.1 and R.sup.2 are independently CH.sub.2PO(OX.sup.1).sub.2 and CH.sub.2PO(OH)OX.sup.2, where X.sup.1 and X.sup.2=H (Lewatit MDS TP 260, degree of substitution of the aminomethyl groups by phosphonic acid groups=2.0, total capacity 3.2 mol/l, H form, d.sub.50 0.385 mm, monodisperse and macroporous), in the H form is dispersed in demineralized water and adjusted to pH=4 with H.sub.2SO.sub.4 in a beaker with stirring. This is followed by the gradual addition of 250 ml of an aqueous Co.sup.2+/Ni.sup.2+/Al.sup.3+ sulfate solution with 6.95 g (0.118 mol/0.027 g/l) of cobalt, 6.93 g (0.118 mol) of nickel and 3.20 g (0.118 mol) of aluminum with stirring. The pH fell from 4.0 to 1.9 in the supernatant of the ion exchanger during the addition of the solution. The supernatant solution is then completely decanted off and volumetrically measured. The chelating resin is washed several times with demineralized water and subjected to suction in order to remove adhering Co, Ni, Al (850 ml of washing water). The loading capacity of the chelating resin containing functional groups of structural element (I) was calculated by the decrease of Al, Ni and Co in the supernatant and is 10.9 g/l (0.4 mol/l) for Al, 0.8 g/l (0.0135 mol/l) for Ni and 1.1 g/l (0.0135 mol/l) for Co. 37.8% of the total capacity of the resin was loaded with aluminum ions.

B. Selective Aluminum Elution with NaOH and Regeneration by Way of Diluted Sulfuric Acid

[0075] In the next step, 20 ml of chelating resin containing functional groups of structural element (I) from A is eluted with 100 ml of aqueous NaOH 9% by weight over the course of 3 hours at 80 C. with stirring. The alkaline solution is then decanted off. Following this, some of the completely regenerated resin is dried and digested in a microwave. The aluminum, nickel and cobalt concentration is determined by means of ICP (inductively coupled plasma spectrometer). The aluminum concentration is below the detection limit. The nickel and cobalt concentration on the chelating resin containing functional groups of structural element (I) remain unchanged within the scope of the detection limits. The remaining chelating resin is washed thoroughly and regenerated with 100 ml of H.sub.2SO.sub.4 15% by weight at room temperature with stirring over the course of 1 hour. After a washing step with 80 ml of deionized water, the supernatant NaOH was removed. The nickel and cobalt that remained on the ion exchanger was eluted within the scope of the detection limits to an extent of virtually 100% by weight by the addition of 15% by weight of H.sub.2SO.sub.4.