METHOD FOR ISOLATING AN AQUEOUS HYDROCHLORIC ACID SOLUTION OF FECL3 FROM AN AQUEOUS MULTI-COMPONENT SYSTEM

Abstract

The invention relates to a method for isolating an aqueous hydrochloric acid solution of FeCl.sub.3 from an aqueous multi-component system.

Claims

1. Method for isolating an aqueous hydrochloric acid solution of FeCl.sub.3 from an aqueous multi-component system, comprising the following steps: a) an aqueous hydrochloric acid multi-component system comprising Fe.sup.3+ ions is provided, b) the multi-component system from step a) is extracted with an organic solvent, c) the organic solvent from step b) is extracted with water, wherein the aqueous hydrochloric acid solution of FeCl.sub.3 is obtained, characterized in that in the multi-component system of step a), the molar ratio of aqueous HCl to Fe.sup.3+ ions is ≥1.3:1.

2. Method according to claim 1, characterized in that the molar ratio of aqueous HCl to Fe.sup.3+ ions is in the range from 1.5:1 to 2.5:1 and preferably in the range from 1.8:1 to 2.3:1.

3. Method according to either of claim 1 or 2, characterized in that the organic solvent comprises or consists of molecules comprising heteroatoms, preferably oxygen, sulfur or nitrogen atoms and particularly preferably oxygen atoms.

4. Method according to either of claim 1 or 2, characterized in that the organic solvent comprises or consists of one or more of the following organic solvents: ethers, alcohols, ketones, and preferably comprises or consists of one or more of the following organic solvents: 2-methoxy-2-methylpropane, diisopropyl ether, butanol, 2-methyl-1-propanol, 2-ethylhexan-1-ol, 4-methylpentan-2-one, 1-chloro-4-methylpentan-2-one, 3-chloro-4-methylpentan-2-one.

5. Method according to either of claim 1 or 2, characterized in that the organic solvent comprises or consists of 4-methylpentan-2-one.

6. Method according to any of claims 1 to 5, characterized in that the extraction in step b) is carried out with the organic solvent in countercurrent.

7. Method according to any of claims 1 to 6, characterized in that the extraction in step b) is a multi-stage extraction, preferably in 3 to 7 stages.

8. Method according to any of claims 1 to 7, characterized in that the extraction in step c) is carried out with water in countercurrent.

9. Method according to any of claims 1 to 8, characterized in that the extraction in step c) is a multi-stage extraction, preferably in 2 to 7 stages.

10. Method according to any of claims 1 to 9, characterized in that the method is carried out at a temperature in the range of 0 to 80° C., preferably in the range of 10 to 50° C. and particularly preferably in the range of 20 to 40° C.

11. Method according to any of claims 1 to 10, characterized in that said method is carried out continuously.

12. Method according to claim 11, characterized in that the organic solvent after the extraction with water in step c) is reused in step b).

13. Method according to any of claims 1 to 12, characterized in that the concentration of Fe.sup.3+ ions in the aqueous multi-component system of step a) is in the range of 0.01 to 2.3 mol/kg, preferably in the range of 0.1 to 2 mol/kg and particularly preferably in the range of 1.1 to 1.7 mol/kg.

14. Method according to any of claims 1 to 13, characterized in that the aqueous multi-component system of step a) comprises dissolved alkali metal salts and/or alkaline earth metal salts and preferably NaCl and/or NaSCN.

15. Method according to claim 14, characterized in that the aqueous multi-component system of step a) comprises dissolved NaCl in the range of 0.01 to 3.5 mol/kg, preferably in the range of 0.1 to 1.5 mol/kg and particularly preferably in the range of 0.3 to 1 mol/kg.

Description

EXAMPLE 1

[0035] An aqueous multi-component system was extracted at 30° C. with 0.99 kg/kg of 4-methylpentan-2-one. The initial ratio of aqueous HCl to Fe.sup.3+ ions in the aqueous multi-component system was 2.6 mol/mol.

[0036] The yield of FeCl.sub.3 in the organic phase after extraction was 100%.

EXAMPLE 2

[0037] An aqueous multi-component system was extracted at 30° C. with 0.85 kg/kg of 4-methylpentan-2-one. The initial ratio of aqueous HCl to Fe.sup.3+ ions in the aqueous multi-component system was 1.3 mol/mol.

[0038] The yield of FeCl.sub.3 in the organic phase after extraction was 96.3%.

EXAMPLE 3

[0039] An aqueous multi-component system was extracted at 40° C. with 0.99 kg/kg of n-butanol. The initial ratio of aqueous HCl to Fe.sup.3+ ions in the aqueous multi-component system was 1.8 mol/mol. The yield of FeCl.sub.3 in the organic phase after extraction was 78.8% by weight.

EXAMPLE 4

[0040] An aqueous multi-component system was extracted at 30° C. with 0.60 kg/kg of 2-methoxy-2-methylpropane. The initial ratio of aqueous HCl to Fe.sup.3+ ions in the aqueous multi-component system was 2.1 mol/mol, and 22% by weight FeCl.sub.3 was present in the system. The yield of FeCl.sub.3 in the organic phase after extraction was 99.2% by weight.

EXAMPLE 5

[0041] An aqueous multi-component system was extracted at 10° C. with 0.61 kg/kg of 2-methoxy-2-methylpropane. The initial ratio of aqueous HCl to Fe.sup.3+ ions in the aqueous multi-component system was 1.5 mol/mol, and 24% by weight FeCl.sub.3 was present in the system. The yield of FeCl.sub.3 in the organic phase after extraction was 92.9% by weight.

EXAMPLE 6

[0042] An aqueous multi-component system was extracted at 30° C. with 0.57 kg/kg of diisopropyl ether. The initial ratio of aqueous HCl to Fe.sup.3+ ions in the aqueous multi-component system was 1.5 mol/mol, and 24% by weight FeCl.sub.3 was present in the system. The yield of FeCl.sub.3 in the organic phase after extraction was 79.9% by weight.

EXAMPLE 7

[0043] The organic solvent of step b) from Example 2, which was charged with FeCl.sub.3 and HCl, was extracted with 0.54 kg/kg of water. FeCl.sub.3 and HCl were entirely extracted into water. The organic solvent 4-methylpentan-2-one discharged contained no iron and only traces of HCl.

EXAMPLE 8

[0044] The organic solvent of step b) from Example 4, which was charged with FeCl3 and HCl, was extracted with 0.6 kg/kg of water. FeCl.sub.3 and HCl were entirely extracted into water. The 2-methoxy-2-methylpropane discharged contained no iron and only traces of HCl.

COMPARATIVE EXAMPLE

[0045] An aqueous multi-component system was extracted at 40° C. with 0.99 kg/kg of 4-methylpentan-2-one. The initial ratio of aqueous HCl to Fe.sup.3+ ions in the aqueous multi-component system was 1.2 mol/mol, and 22% by weight FeCl.sub.3 was present in the system. The yield of FeCl.sub.3 in the organic phase after extraction was 62.9% by weight.