Liquid purification or separation – Processes – Liquid/liquid solvent or colloidal extraction or diffusing...
Patent
1997-01-08
1998-08-18
Wyse, Thomas G.
Liquid purification or separation
Processes
Liquid/liquid solvent or colloidal extraction or diffusing...
252364, 423139, 210911, 210638, C22B 338, C22B 340, C22B 342, C22B 326
Patent
active
057954828
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The present invention relates to the use of hydrocarbon-soluble aminomethylenephosphonic acid derivatives comprising the structural element of the formula I ##STR2## where R.sup.1 and R.sup.2 are hydrogen, C.sub.1 -C.sub.30 -alkyl which can additionally bear up to 15 hydroxyl groups and/or be interrupted by up to 14 non-adjacent oxygen atoms, C.sub.2 -C.sub.30 -alkenyl, C.sub.7 -C.sub.18 -aralkyl or C.sub.6 -C.sub.14 -aryl which can be substituted by up to three C.sub.1 -C.sub.12 -alkyl groups, C.sub.1 -C.sub.12 -alkoxy groups, halogen atoms, cyano groups, hydroxyl groups or C.sub.1 -C.sub.4 -alkoxycarbonyl groups, for the solvent extraction of iron ions from aqueous solutions.
The invention also relates to the additional use of certain modifiers for such solvent extractions of iron ions or, generally, metal ions from aqueous solutions.
DISCUSSION OF THE BACKGROUND
The removal of iron ions from aqueous solutions is particularly important in hydrometallurgical nonferrous metal production, eg. in the winning of copper or zinc. Solutions of desired metals are frequently obtained from ores by digestion or leaching with aqueous, usually acid systems. The interfering metal iron has to be removed from these solutions. In addition, the work-up of metal-containing wastes or residues (eg. flue dusts or precipitation sludges from wastewater treatment) and the recycling of used metal products (eg. catalysts) nowadays play an ever more important role in the provision of aqueous solutions of desired metals. Regardless of the origin of the metal salt solutions, it is always necessary to remove interfering elements, in particular the interfering metal iron, from these solutions of desired metals so that pure metals can be isolated. Apart from improving the quality of the desired metals, recovery of the iron and reducing contamination of landfill areas is also sought for economic and ecological reasons.
The solvent extraction of iron ions is known in the literature. Thus, DE-A 38 01 430 (1) describes the use of a mixture comprising a primary amine and an alkylphosphonic monoester such as mono-2-ethylhexyl 2-ethylhexylphosphonate for the removal of iron(III) ions from acid zinc salt solutions by solvent extraction.
Furthermore, JP-A 1985/077936 (2) discloses that aminomethylenephosphonic acid derivatives are suitable for the solvent extraction of uranium, antimony or bismuth.
US-A 4 741 831 (3) relates to a process for separating metals such as iron, cobalt, copper, vanadium, cadmium, nickel, zinc, lead or aluminum from aqueous solutions using water-soluble polymeric complexing agents, for example polyethyleneiminephosphonates. The metal complex is subsequently separated off by dialysis or ultrafiltration by means of membranes.
However, the above processes of the prior art still have disadvantages. They are mostly not efficient enough and are too uneconomical. In particular, the selectivity of the separation of the interfering metals from the desired metals and the loading capacity of the complexing agents used are still in need of improvement.
SUMMARY OF THE INVENTION
It is an object of the present invention to find an improved system for the solvent extraction of iron ions from aqueous solutions which no longer has the disadvantages of the prior art.
We have found that this object is achieved by the use as defined in the introduction of the hydrocarbon-soluble aminomethylenephosphonic acid derivatives having the structural element I.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Preferably, use is made of hydrocarbon-soluble aminomethylenephosphonic acid derivatives comprising the structural element of the formula Ia ##STR3##
For the purpose described, particular preference is given to hydrocarbon-soluble aminomethylenephosphonic acid derivatives of the general formula II ##STR4## where R.sup.3 to R.sup.6 are each hydrogen, C.sub.1 -C.sub.30 -alkyl which can additionally bear up to 15 hydroxyl groups and/or be interrupted by up to 14 non-adjacent oxygen a
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patent: 4834951 (1989-05-01), Schwab et al.
patent: 5366715 (1994-11-01), Dreisinger et al.
Ehle Michael
Oppenlander Knut
BASF - Aktiengesellschaft
Wyse Thomas G.
LandOfFree
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