CS253033B1 - Method of fe3 plus iones removal - Google Patents

Abstract

Removal of FeJ ions from Al solutions selective sorption is achieved by ions Fe @ + + is removed from the solution by selective sorption on the support anchored by an ehelatation group diethylenetriaminetetraacetic or triethylentetraaminepentaacetic acid at a temperature below 50 ° C and in the range of pH 1 to 3.5.

Description

The invention relates to a process for removing Fe @ ⁺ ions from solutions of aluminum compounds.

The separation of trivalent iron from trivalent aluminum in solution is a very difficult problem due to the similar properties of these ions. An iron content below 5 ppm is required in the preparation of very pure special purpose aluminum compounds. Conventional purification methods, such as crystallization or separation using conventional ion exchangers, are unable to meet these requirements. Effective special cleaning methods are not published. It is known from the analytical chemistry that the logarithm of the stability constants of the free coordination compounds of the Fe @ ⁺ and Al @ ^{+ ions} with ethylenediamine tetraacetate is about 8.

A solution to the problem of removing iron ions from aluminum compound solutions appears to be a process for removing Fe @ ⁺ ions from aluminum compound solutions by the method of the invention, which consists in removing Fe @ ⁺ ions from the solution by selective sorption on a support with anchored diethylenetriamine tetraacetate. triethylenetetraamine pentacetic acid at a temperature below 50 ° C and in the pH range of 1 to 3.5.

The process according to the invention achieves a practically quantitative removal of trivalent iron from alum, aluminum sulphate and other aluminum compounds for the preparation of very pure substances applicable in lighting and elsewhere.

Quantitative removal of iron below the level of 1.10 @ -1 moles Fe @ ^{+ +} is achieved at an initial Fe @ ^{+ +} content of aluminum compounds of from 1 ppm up to tens of percent. The pH of the solution must be maintained from 1 to 3.5, the usual working temperature being about 25 ° C and must not exceed 50 ° C. The available sorption capacity depends on the sorbent flow rate and the particular conditions selected. The regeneration of the functional groups is carried out by desorption of the Fe @ 3 ions with mineral acids having a concentration of 1 to 3 moles. After regeneration, the chelotation sorbent is reused,

In practice, the process according to the invention can be carried out by passing a solution of aluminum compounds with a certain iron (III) content through a column packed with psrulose cellulose or another carrier with chelating groups diethylenetriaminetetraacetic in the side chains. There are practically no limitations on the inlet concentration of the purified solution in terms of concentration.

In the longer term, the invention is illustrated and documented by way of example.

Example 1

At 23 ° C, a saturated solution of alummonium aluminum sulphate (NH 3 Al (SO 4) ₂ .12 H ₂ O) was prepared at pH 3.1, which, in addition to 135.1 g NH 4 .alpha. ppm Fe @ ^+, 0.1 ppm Ca, 0.1 Mg porn, No. 0.1 ppm and 5 ppm K. 1000 ml of this solution through a column of diameter 15 mm filled with cellulose beads with anchored functional groups dietylentriamintetraoctovýrni rate of 4 ml / min at 85 mm column height.

The trapped iron content after desorption was 0.0068 mol, i.e. P, 38 mg of iron. Thus, 76% of the trivalent iron initially present was removed from the purified aluminum ammonium sulfate. The Fe ^J content of the purified solution was 0.9 ppm.

Example 2

3+

The ammonium aluminum sulphate solution of Example 1 was doped with Fe ions to a concentration of, 1/5 moles F <P ⁺ , i.e. 25 ppm Fe ^ ⁺ based on ammonium aluminum sulphate. At pH 3 and a temperature of 20 ° C, the solution was purified by flowing through a column packed with diethylenetriamine tetraacetate pearl cellulose at a rate of 10 ml / min at a 3 mm column size of 150 mm and a packing height of 150 mm. 1000 ml of the solution was free of Fe ions up to a content below 1 ppm.

Example 3

A solution of 0.0876 moles of ammonium aluminum sulfate was prepared from the solution of Example 1. iron was added to a content of 6.7.10 ^-4 moles of Fe ^ ⁺ , ie to a content of 946 ppm Fe ^ ⁺ based on alumina sulphate. At pH 3 and 23 ° C, the removal of iron ions was carried out by passing the solution through a column packed with diethylenetriaminetetraacetate functionalized pearl cellulose at a rate of 10 ml / min at a filling height of 150 mm and a diameter of 15 mm. 1000 ml of the solution was free of Fe ^{J +} ions below 1 ppm, another 500 ml of the solution contained less than 8 ppm of iron.

Example 4

To an aluminum sulfate solution containing 179 .mu.g / l. 18 HgO, i.e., 0.585 moles

A1 ^J Fe ions were added to a concentration of 0.001 ^J mol Fe ^J. The pH of the solution was adjusted to

3. All iron was removed from the first 600 ml solution by flowing through a 15 mm diameter column packed to a height of 85 mm with diethylentriamine tetraacetate-anchored pearl cellulose at a rate of 4 ml / min. The content of 100 ml of eluate was 2 ppm

Claims (1)

Method for removing Fe @ ⁺ ions from aluminum compound solutions, characterized in that Fe @ ⁺ ions are removed from the solution by selective sorption on a support with an anchored diethylenetriaminetetraacetate or triethylenetetraaminepettaacetate supported at a temperature below 50 ° C. and in the range of pH 1 to 3.5.