Compositions – Absorptive – or bindive – and chemically yieldive
Reexamination Certificate
2001-11-27
2004-05-11
Bos, Steven (Department: 1754)
Compositions
Absorptive, or bindive, and chemically yieldive
C423S024000, C423S099000, C423S139000
Reexamination Certificate
active
06733688
ABSTRACT:
The present invention concerns a solvent extraction composition, a solvent extraction process and especially a process for the extraction of metals, particularly copper, from aqueous solutions, especially solutions obtained by leaching ores.
It is known to extract metals, especially copper, from aqueous solutions containing the metal in the form of, for example, a salt, by contacting the aqueous solution with a solution of a solvent extractant in a water immiscible organic solvent and then separating the solvent phase loaded with metal, i.e. containing at least a part of the metal in the form of a complex. The metal can then be recovered by stripping with a solution of lower pH followed for example, by electrowinning. Most commonly, the aqueous metal-containing solutions for extraction are the result of the acid leaching of ores. However it is known that some metals, especially copper, can be leached from certain ores with ammoniacal solutions. This has the advantage that solutions containing especially high concentrations of copper are derived and that there is little contamination of the solution with iron.
Solvent extractants which have found favour in recent years particularly for the recovery of copper from aqueous solutions include oxime reagents, especially o-hydroxyaryloximes and o-hydroxyarylketoximes. Whilst such reagents have been found to work well in the recovery of copper from solutions, one problem which has been encountered in the application of such reagents is that the oxime and ketoxime reagents can strongly bind metals to the extent that the efficiency of metal transfer from leach solution to strip solution can be impaired. In order to overcome such problems, modifiers have been used to effect the binding efficiency of the extractants. Typical modifiers are disclosed in WO96/25525 and in EP-A-0202833. However, as solvent extraction processes are increasingly employed in more diverse situations, there is still a need to identify further modifiers.
According to a first aspect of the present invention, there is provided a solvent extraction composition comprising one or more orthohydroxyarylaldoximes or orthohydroxyarylketoximes, and at least one dialkyl ester of an optionally substituted ethylene or polyethylene glycol. The compositions preferably also comprise a water immiscible organic solvent.
The orthohydroxyarylaldoxime or orthohydroxyarylketoxime compounds employed in the present invention are substantially water insoluble and preferably have the formula:
wherein
R
1
is hydrogen or an optionally substituted hydrocarbyl group
R
2
is an optionally substituted ortho-hydroxyaryl group, and salts thereof.
Whilst the invention is described herein with reference to a compound of Formula (1), it is understood that it relates to said compound in any possible tautomeric forms, and also the complexes formed between orthohydroxyarylaldoximes or orthohydroxyarylketoximes and metals, particularly copper.
Optionally substituted hydrocarbyl groups which may be represented by R
1
preferably comprise optionally substituted alkyl and aryl groups including combinations of these, such as optionally substituted aralkyl and alkaryl groups.
Examples of optionally substituted alkyl groups which may be represented by R
1
include groups in which the alkyl moieties can contain from 1 to 20, especially from 1 to 4, carbon atoms. A preferred orthohydroxyarylketoxime is one in which R
1
is alkyl, preferably containing up to 20, and especially up to 10, and more preferably up to 3 saturated aliphatic carbon atoms, and in a most preferred orthohydroxyarylketoxime R
1
is a methyl group.
Examples of optionally substituted aryl groups which may be represented by R
1
include optionally substituted phenyl groups. When R
1
is an aryl group, it is preferably an unsubstituted phenyl group.
Most preferably R
1
represents a hydrogen atom.
Optionally substituted ortho-hydroxyaryl groups which may be represented by R
2
include optionally substituted phenols. Examples of optionally substituted phenols which may be represented by R
2
include those of formula:
wherein R
3
to R
6
each independently represent H or a C
1
to C
22
, preferably a C
7
to C
15
, linear or branched alkyl group. Particularly preferably only R
5
represents a C
1-22
alkyl group, most preferably a C
7
to C
15
alkyl group, with R
3
, R
4
and R
6
representing H.
When R
1
or R
2
is substituted, the substituent(s) should be such as not to affect adversely the ability of the orthohydroxyarylaldoxime or orthohydroxyarylketoxime to complex with metals, especially copper. Suitable substituents include halogen, nitro, cyano, hydrocarbyl, such as C
1-20
-alkyl, especially C
1-10
-alkyl; hydrocarbyloxy, such as C
1-20
-alkoxy, especially C
1-10
-alkoxy; hydrocarbyloxycarbonyl, such as C
1-20
-alkoxycarbonyl, especially C
1-10
-alkoxycarbonyl; acyl, such as C
1-20
-alkylcarbonyl and arylcarbonyl, especially C
1-10
-alkylcarbonyl and phenylcarbonyl; and acyloxy, such as C
1-20
-alkylcarbonyloxy and arylcarbonyloxy, especially C
1-10
-alkylcarbonyloxy and phenylcarbonyloxy. There may be more than one substituent in which case the substituents may be the same or different.
In many embodiments, when an orthohydroxyarylketoxime is employed, the orthohydroxyarylketoxime is a 5-(C
8
to C
14
alkyl)2-hydroxyacetophenone oxime, particularly 5-nonyl-2-hydroxyacetophenone oxime.
In many preferred embodiments, when an orthohydroxyarylaldoxime employed, the orthohydroxyarylaldoxime is a 5-C
8
to C
14
alkyl)-2-hydroxybenzaldoxime, particularly 5-nonyl-2-hydroxybenzaldoxime.
The composition may comprise one or more different orthohydroxyarylaldoximes or orthohydroxyarylketoximes or mixtures thereof in which the nature of the substituent groups represented by R
1
and R
2
differ between component orthohydroxyarylaldoximes or orthohydroxyarylketoximes, especially where the component oximes are isomeric. Such isomeric mixtures may have better solubility in organic solvents than a single oxime.
The orthohydroxyarylaldoximes or orthohydroxyarylketoximes are often present in an amount of up to 60% by weight of the composition, commonly no more than 50%, and usually no more than 40% w/w. Often, the orthohydroxyarylaldoxime or orthohydroxyarylketoxime comprises at least 1% by weight, commonly at least 2.5% by weight and usually at least 5% by weight of composition, and preferably comprises from 7.5 to 20%, more preferably 10 to 18%, such as about 15%, by weight of the composition.
The dialkyl esters of an optionally substituted ethylene or polyethylene glycol employed in the present invention are substantially water insoluble and commonly have the formula:
wherein
R
7
and R
8
are each independently an optionally substituted alkyl group;
R
9
to R
20
are each independently hydrogen or optionally substituted hydrocarbyl;
m, n and p are each independently 0, 1, 2, 3 or 4 provided that m+n+p is greater than or equal to 1; and
q is 1, 2 or 3.
The dialkyl esters of an optionally substituted ethylene or polyethylene glycol (hereinafter Esters) of the present invention often contain from 10 to 100 carbon atoms, preferably from 16 to 70 carbon atoms, such as up to 40 carbon atoms, and more preferably from 20 to 30 carbon atoms.
Optionally substituted alkyl groups which may be represented by R
7
and R
8
include groups in which the alkyl moieties often contain from 1 to 25 carbon atoms, preferably from 2 to 16 carbon atoms and especially from 4 to 12, carbon atoms. Alkyl groups which may be represented by R
7
and R
8
are preferably branched. It is especially preferred that when an alkyl group represented by R
7
and R
8
is branched, that branching be alpha to the carbonyl groups to which R
7
and R
8
are attached.
Optionally substituted hydrocarbyl groups which may be represented by any of R
9
to R
20
preferably comprise optionally substituted alkyl and aryl groups including combinations of these, such as optionally substituted aralkyl and alkaryl groups.
Examples of optionally substituted alkyl groups which may be represented
Cupertino Domenico Carlo
Sugarman Alan David
Bos Steven
Cytec Technology Corp.
Pillsbury & Winthrop LLP
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