MODIFICATEURS DESTINES A DES SOLVANTS D'EXTRACTION ALDOXIME DE METAUX PRECIEUX

MODIFIERS FOR ALDOXIME EXTRACTANT OF METAL VALUES

Abrégé français

On emploie des modificateurs d'équilibre différents, avec des solvants d'extraction aldoxime, tels que l'hydroxyle aryle aldoxime, dans le procédé d'extraction de métaux précieux, notamment du cuivre, dans l'extraction à partir de solutions aqueuses, le solvant d'extraction et les modificateurs étant utilisés dans une phase de solvant organique, lequel est un solvant d'hydrocarbure, non miscible avec l'eau et non soluble dans celle-ci, tel qu'un kérosène.

Abrégé anglais

Alternative equilibrium modifiers for use with aldoxime extractants, such as
hydroxyl aryl aldoxime extractants, employed in the
process for extraction of metal values, particularly copper values, in the
extraction from aqueous solutions, in which the extractant and
modifiers are employed in an organic solvent phase, the solvent being a water
insoluble, water immiscible hydrocarbon solvent, such as a
kerosene.

Revendications

37
It is claimed:
1. A water insoluble reagent composition comprising an
aldoxime extractant and an equilibrium modifier
selected from the group consisting of aliphatic,
aromatic and araliphatic compounds containing up to
36 carbon atoms in a molar ratio of aldoxime to
modifier of 0.2 to about 1.5 so as to provide a net
copper transfer greater than that achieved in the
absence of modifier, and up to about 20% by weight
of a kinetic additive, said modifier being selected
from the group consisting of:
(i) a carboxylic acid ester selected from the
group consisting of
(a) a branched ester having a ratio of
methyl groups to non-methyl groups less
than 1:5;
(b) an ester of a monocarboxylic acid
selected from the group consisting of:
methyl decanoate;
2-pentyl octanoate;
n-hexyl octanoate;
(c) an ester of a diol having up to 6 carbon
atoms and a monocarboxylic acid
containing about 6-16 carbon atoms; and
(d) an alkyl ester of a dicarboxylic acid
wherein the alkyl group contains from 1
to about 6 carbon atoms and the
dicarboxylic acid contains from about 4
to about 12 carbon atoms;
(ii) polyethers;

38
(iii) ethers other than nonyl anisole;
(iv) ester-ethers;
(v) ketones;
(vi) nitriles;
(vii) carbonates;
(viii) an amide selected from the group consisting
of:
N,N'-di(2-ethylhexyl) urea;
N,N-bis-2-ethylhexyl 2 ethyl hexanamide;
N-hexyl 2-ethylhexanamide;
N,N-dibutyl 2-ethyl hexanamide;
N,N-dibutylbenzamide;
N,N-dibutyl octanamide;
N,N-dimethyl octanamide, and
N,N-bis-2-ethylhexyl versatamide;
(ix) sulfoxides;
(x) carbamates; and
(xi) salts of amines and quaternary ammonium
compounds.
2. A reagent composition as defined in claim 1, wherein
said aldoxime is an hydroxy aryl aldoxime of the
formula:
<IMG>

39
in which a has a value of 1, 2, 3 or 4, R is a
saturated aliphatic group of about 1 to about 25
carbon atoms or an ethylenically unsaturated
aliphatic group of 3 to about 25 carbon atoms, and
the total number of carbon atoms in R a is from 3 to
about 25.
3. An extraction reagent composition as defined in
claim 1, wherein said aldoxime extractant is
selected from the group consisting of 2-hydroxy-5-
heptylbenzaldoxime, 2-hydroxy-5-octylbenzaldoxime,
2-hydroxy-5-nonylbenzaldoxime and 2-hydroxy-5-
dodecyl benzaldoxime.
4. An extraction reagent composition as defined in
claim 1, wherein said aldoxime extractant is 2-
hydroxy-5-nonyl or dodecyl benzaldoxime.
5. An extraction reagent composition as defined in
claim 1 wherein said aldoxime extractant is 2-
hydroxy-5-dodecylbenzaldoxime.
6. An extraction reagent composition as defined in
claim 1 wherein the aldoxime extractant is 2-
hydroxy-5-nonylbenzaldoxime.
7. An extraction reagent composition as defined in
claim 2, wherein said modifier is a branched ester,
having a ratio of methyl groups to non-methyl groups
less than 1:5.
8. An extraction reagent composition as defined in

40
claim 2, wherein said modifier is an ester of a
monocarboxylic acid selected from the group
consisting of methyl decanoate, 2- pentyl octanoate,
and n-hexyl octanoate.
9. An extraction reagent composition as defined in
claim 2, wherein the modifier is an ester of a diol
having up to about 6 carbon atoms and a
monocarboxylic acid containing about 6 to about 16
carbon atoms.
10. An extraction reagent composition as defined in
claim 9, wherein said ester is 1,4-butane diol
dihexanoate.
11. An extraction reagent composition as defined in
claim 2, wherein the modifier is an alkyl ester of a
dicarboxylic acid wherein the alkyl group contains
from 1 to about 6 carbon atoms and the dicarboxylic
acid contains from about 4 to about 12 carbon atoms.
12. An extraction reagent composition as defined in
claim 11 wherein said dicarboxylic acid is adipic
acid and the alkyl group is selected from the group
consisting of isobutyl and butyl.
13. An extraction reagent composition as defined in
claim 2, wherein said modifier is an ester-ether.
14. An extraction reagent composition as defined in

41
claim 13, wherein the ester-ether is selected from
the group consisting of bis-2-ethoxyethyl adipate,
dipropylene glycol dibenzoate, propylene glycol
dibenzoate and polypropylene dibenzoate.
15. An extraction reagent composition as defined in
claim 2, wherein said modifier is polyether.
16. An extraction reagent as defined in claim 15,
wherein said ether is selected from the group
consisting of benzyl 2-alkoxy alkyl ethers in which
the alkoxy group contains from 2 to about 6 carbon
atoms and the alkyl group contains from 1 to about
6 carbon atoms.
17. An extraction reagent composition as defined in
claim 16, wherein the benzyl ether is selected from
the group consisting of benzyl 2-(2-butoxyethoxy)
ethyl there and benzyl 2-butoxy ethyl ether.
18. An extraction reagent as defined in claim 2, wherein
said modifier is an alkyl carbonate in which the
alkyl group contains from about 4 to about 16 carbon
atoms.
19. An extraction reagent composition as defined in
claim 18, wherein said carbonate is selected from
the group consisting of isobutyl carbonate,
isotridecyl carbonate and a mixed 8 and 10 carbon
atom alkyl carbonate.
20. An extraction reagent composition as defined in

42
claim 2, wherein said modifier is an alkyl ketone in
which the alkyl group contains from about 1 to about
20 carbon atoms.
21. An extraction reagent composition as defined in
claim 20, wherein the ketone is selected from the
group consisting of isobutyl heptyl ketone,
diundecyl ketone and 5,8-diethyldodecane-6,7-dione.
22. An extraction reagent composition as defined in
claim 2, wherein said modifier is a nitrile having
an aliphatic or araliphatic hydrocarbon group
containing from about 10 to about 36 carbon atoms.
23. An extraction reagent composition as defined in
claim 22, wherein said nitrile is selected from the
group consisting of undecyl cyanide, the dinitrile
of an oxo acid containing about 21 carbon atoms,
oleonitrile and the dinitrile of a dimerized
unsaturated 18 carbon atom fatty acid having about
36 carbon atoms.
24. An extraction reagent composition as defined in
claim 2, wherein said modifier is a carbamate.
25. An extraction reagent composition as defined in
claim 24, wherein said carbamate is selected from
the group consisting of N-octyl isotridecylcarbamate
and isotridecyl N-tolylcarbamate.
26. An extraction reagent composition as defined in
claim 2, wherein said modifier is an amide selected

43
from the group consisting of N,N'-bis-2-ethylhexyl
urea, N,N-bis-2-ethylhexyl 2-ethylhexanamide, N-
hexyl 2-ethylhexanamide, N,N-dibutyl 2-
ethylhexanamide, N,N-dibutyl benzamide, N,N-dibutyl
octanamide, N,N-dimethyl octanamide, N,N-bis-2-
ethylhexyl versatamide.
27. An extraction reagent composition as defined in
claim 2, wherein said modifier is a sulfoxide.
28. An extraction reagent composition as defined in
claim 27, wherein said sulfoxide is di-2-ethylhexyl
sulfoxide.
29. An extraction reagent composition as defined in
claim 2, and further comprising a second modifier in
admixture, said second modifier being selected from
the group consisting of an alkanol having from about
6 to about 18 carbon atoms, an alkyl phenol in which
the alkyl group contains about 7 to about 12 carbon
atoms, and tributylphosphate.
30. An extraction reagent composition as defined in
claim 2, wherein said modifier is a salt of an amine
compound selected from the group consisting of
tertiary amines and quaternary ammonium compounds
containing alkyl groups having from about 8 to about
18 carbon atoms.
31. An extraction reagent composition as defined in
claim 30, in which said salt is a sulfonic acid
salt.

44
32. An extraction reagent composition as defined in
claim 31, wherein the salt is selected from the
group consisting of the dinonylnaphthalene sulfonic
acid and toluene sulfonic acid salts.
33. A water insoluble, water-immiscible hydrocarbon
solvent solution of the extraction reagent
composition defined in claim 2.
34. A solvent solution as defined in claim 33, wherein
the hydrocarbon solvent is kerosene.
35. A process for recovery of copper from an aqueous
solution containing copper values comprising
(1) contacting the aqueous solution with an
organic phase comprising a water insoluble and water
immiscible solvent solution of the extraction
reagent composition defined in claim 2, to extract
at least a portion of the copper values into the
organic phase;
(2) separating the resultant copper pregnant
organic phase from the resultant copper barren
aqueous phase; and
(3) recovering the copper values from the
copper pregnant organic phase.
36. A process as defined in claim 35, wherein the water
insoluble and water immiscible solvent is kerosene.
37. A process as defined in claim 35, wherein the
recovering of the copper values from the copper

45
pregnant organic phase of step (3) comprises
stripping the copper values from the copper pregnant
organic phase by means of an acid.
38. A metal aldoxime extractant modifier compound
selected from the group consisting of:
1,4-butanediol dihexanoate
1,6-hexanediol dihexanoate
2-pentyl octanoate
bis-2-ethoxyethyl adipate
benzyl 2-(2-butoxyethoxy)ethyl ether
benzyl 2-butoxyethyl ether
N,N-dimethyl isooctanamide
tridecyl-N-tolyl carbamate
N-octyl isotridecylcarbamate
N,N1-bis 2-ethylhexyl urea
N,N1-bis 2-ethylhexyl 2-ethylhexanamide
N-hexyl 2-ethylhexanamide
5,8-diethyldodecane-6,7-dione
N,N-dibutyl 2-ethylhexanamide
N,N-dibutyl benzamide
N,N-dibutyl octanamide.

Description

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WO 96/25525 PCT/US96/01116
1
MODIFIERS FOR ALDOXIME EXTRACTANT
OF METAL VALUES
BACKGROUND OF THE INVENTION
Field of the Invention:
This invention relates to the extraction of metal
values from aqueous solutions and in particular to
modifiers for aldoxime extractant employed for extraction
of metals, particularly copper values.
Statement of Related Art:
The present invention relates generally to solvent
extraction processes for recovery of metal values from
aqueous solutions and, more particularly, to formulative
procedures for developing improved solvent extraction
reagents and to the use of such reagents in recovery of,
e.g., copper values.
The starting material for large scale solvent
extraction processing of copper is an aqueous leach
solution obtained from a body of ore which contains a
mixture of metals in addition to copper. The leaching
medium dissolves salts of copper and other metals as it
trickles through the ore, to provide an aqueous solution of
the mixture of metal values. The metal values are usually
leached with sulfuric acid medium, providing an acidic

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aqueous solution, but can also be leached by ammonia to
provide a basic aqueous solution.
The aqueous solution is mixed in tanks with an =
extraction reagent which is dissolved in an organic
solvent, e.g., a kerosene. The reagent includes an =
extractant chemical which selectively forms metal-
extractant complex with the copper ions in preference to
ions of other metals. The step of forming the complex is
called the extraction or loading stage of the solvent
extraction process.
The outlet of the mixer continuously feeds to a large
settling tank, where the organic solvent (organic phase),
now containing the copper-extractant complex in solution,
is separated from the depleted aqueous solution (aqueous
phase). This part '-of the process is called phase
separation. Usually, the process of extraction is repeated
through two or more mixer/settler stages, in order to more
completely extract the desired metal.
After extraction, the depleted aqueous feedstock
(raffinate) is either discharged or recirculated to the ore
body for further leaching. The loaded organic phase
containing the dissolved copper-extractant complex is fed
to another set of mixer tanks, where it is mixed with an
aqueous strip solution of concentrated sulfuric acid. The
highly acid strip solution breaks apart the copper-
extractant complex and permits the purified and
concentrated copper to pass to the strip aqueous phase. As
in the extraction process described above, the mixture is
fed to another settler tank for phase separation. This
process of breaking the copper-extractant complex is called
the stripping stage, and the stripping operation is
repeated through two or more mixer-settler stages to more
completely strip the copper from the organic phase.
From the stripping settler tank, the regenerated
stripped organic phase is recycled to the extraction mixers
to begin extraction again, and the strip aqueous phase is
customarily fed to an electrowinning tank-house, where the

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copper metal values are deposited on plates by a process of
electrodeposition. After electrowinning the copper values
from the aqueous solution, the solution, known as spent
electrolyte, is returned to the stripping mixers to begin
stripping again.
Modifiers of extraction and stripping equilibria are
frequently incorporated in those commercial reagent
formulations which include the so-called "strong"
extractants. Such extractants are capable of forming a
very stable complex association with copper at quite low
pH's and, consequently, require the use of very highly
acidic aqueous stripping solutions in order to effect the
breakdown of the copper-extractant complex. Where extreme
acidity of stripping solutions generates problems in
employing conventional electrodeposition processes,
modifiers are incorporated to shift equilibria in a manner
facilitating stripping at lower acidities and to enhance
overall metal extraction efficiency. A wide variety of
modifier chemicals has been proposed for use in formulation
of solvent extraction reagents for copper. These have
included: long chain (C6 to C20 ) aliphatic alcohols such as
isodecanol, 2-ethylhexanol, and tridecanol; long chain
alkyl phenols such as nonylphenol.
The use of kinetic additives and equilibrium modifiers
has not been without drawbacks in the overall efficiency of
solvent extraction processes in terms of the long range
stability of reagents and the sensitivity of reagents to
contaminants in aqueous feedstocks. Amines such as
tertiary amines (Alamine 336) are very strong modifiers of
oximes but due to their tendency to transfer acid into the
organic phase, amines also catalyze the hydrolysis of the
= oximes. However, by pairing a strongly acidic organic acid
with the amine to form a salt, one can still achieve very
strong modification of the oxime, while minimizing the rate
of hydrolysis of the oxime. Also, as an example, while the
minor proportion of kinetic additive present with the
hydroxy aryl ketoxime extractant in the LIX 64N reagent

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formulation provides for kinetic enhancement in the use of
the ketoxime, the additive is less stable toward hydrolytic
degradation than the ketoxime. When used under operating
conditions which are optimal for ketoxime extractant
efficiency, the aliphatic a-hydroxy oxime thus tends to be
depleted from continuous system more rapidly than the
ketoxime. Similarly, hydroxy aryl aldoxime extractants are
less stable in use than ketoximes and are rendered even
more unstable by the presence of large quantities of
nonylphenol. Alkyl phenol equilibrium modifiers, have also
been noted to have severe deleterious effects on structural
components of solvent extraction facilities, such as rubber
linings, fittings, valves and the like.
In some cases, the combination of the modifier used in
the extractant, with%the contaminants present in the
aqueous feedstock results in the generation of interfacial
crud which must be continually removed from the solvent
extraction circuit. In these cases, it is desirable to run
with the minimum amount of modifier to achieve effective
stripping and maximum net copper transfer, while at the
same time, minimizing crud formation.
As is apparent from the foregoing, there exists a
general need in the art for reagents for solvent extraction
for the recovery of copper values which display efficient
characteristics preferably with diminished quantities of
additive or equilibrium modifiers. There is accordingly a
need for modifiers which will provide increased net copper
transfer by an extractant such as an aldoxime extractant.
U.S. Patent 4,507,268 to Henkel Corporation describes
extraction reagents formulated with various oxime
extractants, including hydroxyaryl aldoxime extractants,
which are employed in water immiscible organic solvents,
such as kerosene, with certain equilibrium modifiers such
as, phenols and alcohols (tridecanol, a commercially
available branched chain alcohol) or tributyl phosphate.
In def ining the amount of modifier which would result in
increased net copper transfer with the particular aldoxime

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employed, exempliai6a mol~e satticularly by 2-hydroxy-5-
nonylbenzaldoxime, the patentee developed a "degree of
modification" test. As employed there and herein, "degree
of modification" designates the inverse ratio of (a) the
5 stripped solvent copper level of an hydroxy aryl aldoxime
extractant at equilibrium (expressed in terms of grams per
liter of copper) extracted with an aqueous solution
containing a fixed concentration of copper and sulfuric
acid to (b) the stripped solvent copper level of the same
extractant under the same conditions when a selected
equilibrium modifier additive is present. Consistent with
this definition, the presence of relatively small
quantities of an equilibrium modifier will shift the
extraction equilibrium slightly, resulting in minor
diminution of aldoxime=stripped solvent copper level at
equilibrium, as will be reflected by a degree of
modification value closely approaching 1.0, e.g., 0.99.
Increased effective quantities of modifier under otherwise
identical conditions will result in a more pronounced shift
in extraction equilibrium and a more pronounced diminution
of aldoxime stripped solvent copper level at equilibrium,
as will be reflected by a degree of modification
corresponding less than 1Ø
Expectedly the degree of modification resulting from
a given molar ratio of equilibrium modifier to aldoxime in
a reagent will vary depending on various factors, most
significantly the chemical identity and nature of the
equilibrium modifier, but also the conditions involved in
determining the degree of modification of an aldoxime by a
given equilibrium modifier. In U.S. Patent 4,507,268 the
following test conditions were to be adhered to for
purposes of determining the degree of modification. The
temperature at which the determination is made should be
about 24 C. The molar concentration of aldoxime (or
mixture of aldoximes) in the diluent should be about 0.184
as determined by copper loading and titration and an
aldoxime stock of approximately 94 percent purity (with the

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remainder being substantially alkyl phenol starting
material residue) should be employed. The diluent should
be Escaid 100 or a mixture of aliphatic and aromatic
hydrocarbons closely approximating the constitution of
Escaid 100. An atomic absorption methodology should be
employed for determining copper content. The composition
of the strip solution should be 150 g/l sulfuric acid and
30 g/l Cu+2 .
U.S. Patent 4,142,952 similarly employed a mixture of
5-nonylphenols as a modifier for oximes such as 5-nonyl or
5-heptyl salicylaldoxime.
More recently, U.S. patent 4,978,785 described the use
of branched chain aliphatic or aromatic-aliphatic (or
aliphatic) alcohols containing 14 to 30 carbon atoms or
aliphatic or aromatic-&liphatic esters containing 10 to 30
carbon atoms wherein the ratio of the number of methyl
carbon atoms to the number of non-methyl carbon atoms is
higher than 1:5.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a graph representation of the modifier
evaluation of extraction points of mixtures of nonylphenol
(NP) and trioctyiphosphate (TOP) with dodecyl
salicylaldoxime extractant (DSAdO).
Figure 2 is a similar graph representation of the
strip point of the mixture of NP and TOP.
Figure 3 is another graph representation of the
modifier evaluation extraction points of mixtures of
isotridecanol (TDA) and trioctylphosphate (TOP) with
dodecylsalicylaldoxime extractant (DSAdO).
Figure 4 is a similar graph representation of the
modifier strip point of the mixtures of TDA, and TOP with DSAdO.
DESCRIPTION OF THE INVENTION
The present invention provides alternative equilibrium
modifiers for use with aldoxime extractants such as the

CA 02213102 2007-05-17
7
hydroxy aryl aldoxime extractants. Efficient copper
recovery is achieved by reagents which comprise mixtures
of hydroxy aryl aldoximes and the modifiers to be
described hereafter in more detail.
More particularly the present invention provides a
water insoluble reagent composition comprising an
aldoxime extractant and an equilibrium modifier selected
from the group consisting of aliphatic, aromatic and
araliphatic compounds containing up to 36 carbon atoms in
a molar ratio of aldoxime to modifier of 0.2 to about 1.5
so as to provide a net copper transfer greater than that
achieved in the absence of modifier, and up to about 20%
by weight of a kinetic additive, said modifier being
selected from the group consisting of:
(i) a carboxylic acid ester selected from the
group consisting of
(a) a branched ester having a ratio of
methyl groups to non-methyl groups less
than 1:5;
(b) an ester of a monocarboxylic acid
selected from the group consisting of:
methyl decanoate;
2-pentyl octanoate;
n-hexyl octanoate;
(c) an ester of a diol having up to 6 carbon
atoms and a monocarboxylic acid
containing about 6-16 carbon atoms; and
(d) an alkyl ester of a dicarboxylic acid
wherein the alkyl group contains from 1
to about 6 carbon atoms and the

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7a
dicarboxylic acid contains from about 4
to about 12 carbon atoms;
(ii) polyethers;
(iii) ethers other than nonyl anisole;
(iv) ester ethers;
(v) ketones;
(vi) nitriles;
(vii) carbonates;
(viii) an amide selected from the group consisting
of:
N,N'-di(2-ethylhexyl) urea;
N,N-bis-2-ethylhexyl 2 ethyl hexanamide;
N-hexyl 2-ethylhexanamide;
N,N-dibutyl 2-ethyl hexanamide;
N,N-dibutylbenzamide;
N,N-dibutyl octanamide;
N,N-dimethyl octanamide, and
N,N-bis-2-ethylhexyl versatamide;
(ix) sulfoxides;
(x) carbamates; and
(xi) salts of amines and quaternary ammonium
compounds.
Hydroxy aryl aldoxime extractants with which the
modifiers of the present invention are particularly
useful are those of the formula

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7b
OH NOH
C
H
Ra
in which a has a value of 1, 2, 3 or 4, R is a
saturated aliphatic group of about 1 to about 25 carbon
atoms or an ethylenically unsaturated aliphatic group of
3 to about 25 carbon atoms, and the
total number of carbon atoms in Ra is from 3 to about 25.
Preferred compounds are those wherein a is 1, and R is a
straight or branched chain alkyl group having from about
7 to about 12 carbon atoms and wherein R is attached in a
position para to the hydroxyl group. Among these, the
more preferred are those wherein R is a mixture of
isomers. Compounds which are especially useful include 2-
hydroxy-5-heptylbenzaldoxime, 2-hydroxy-5-
octylbenzaldoxime, 2-hydroxy-5-nonylbenzaldoxime and 2-
hydroxy-5-dodecylbenzaldoxime.
In its broadest aspect, the present invention
relates to reagent compositions, which are suitable for
extracting copper from aqueous solutions containing
copper values, i.e., copper salts, and to the process of
extracting copper using such compositions. The extraction
reagent compositions comprise a mixture of an hydroxy
aryl aldoxime extractant and certain equilibrium
modifiers in which the

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equilibrium modifier is present in an amount to provide a
net copper transfer greater than that achieved by
extraction with the aldoxime alone, without the presence of
the modifier. If desirable to affect the kinetics, a
kinetic additive may optionally also be included. Thus, in
use the reagent composition may optionally contain a
kinetic additive in an amount of 0 to about 20 mole percent
based on the aldoxime content. Such kinetic additives are
well known to those skilled in the oxime extraction art for
extracting copper, such as those disclosed in U.S. Patent
4,507,268 to Kordosky et al., including a-hydroxy oxime
prepared according to Swanson, U.S. Patent 3,224,873 or
U.K. Patent 1,537,828 and a,(3-dioximes according to
Koenders et al., U.S. Patent 4,173,616. A preferred a-
hydroxy oxime kineti& additive is 5,8-diethyl-7-hydroxy
dodecane-6-oxime and a preferred dioxime kinetic additive
is a mixture of 1-(4'-alkylphenyl)-1,2-propanedione
dioximes, according to Example 3 of U.S. Patent 4,176,616.
As indicated in the Related Art section, in the past
equilibrium modifiers for oxime copper extractant were the
alkyl phenols in which the preferred alkyl group contained
from about 7 to about 12 carbon atoms, long chain aliphatic
alcohols containing from about 6 up to about 30 carbon
atoms and organophosphorus compounds such as
tributylphosphate (U.S. Patent 4,507,268). U.S. Patent
4,928,788 also describes as modifiers certain branched
chain aliphatic or aromatic aliphatic alcohols containing
14 to about 30 carbon atoms and certain aliphatic or
aromatic aliphatic esters containing from 10 to 30 carbon
atoms, wherein the ratio of the number of methyl carbon
atoms to the number of non-methyl carbon atoms is higher
than 1:5.
The present invention accordingly provides alternative
modifiers to those used in the past, which provide at least
equivalent, and in many cases, improved results, in the net
copper transfer, to those modifiers employed in the past.
If desired, the present modifiers may optionally be

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employed in admixture with those used in the past to
further modify the results.
As indicated, the modifiers of the present invention
are employed in an amount to provide a net copper transfer
greater than that achieved in the absence of the modifier.
As in U.S. Patent 4,507,268, the amount of modifier can be
further def ined by means of the degree of modif ication
determined as described in that patent and as earlier noted
in the Related Art section above. The useful and preferred
range of degree of modification will vary dependent on the
particular modifier compound and it is accordingly
difficult to define a general range which will apply to all
the individual modifiers, other than as the amount thereof
being an amount effective to provide a net copper transfer
greater than that achieved in the absence of the modifier.
For example, in the case of the alkyl phenols, the most
desirable, useful degree of modification range was from
about 0.75 up to, but less than, about 1.0, preferably from
about 0.90 and approaching, but not including 1.0, i.e.,
0.99, whereas with modifiers other than the phenols, such
as alcohols, like tridecanol, or alkylphosphates, such as
tributylphosphate, the useful range of degree of
modification may be from about 0.66 or even lower up to,
but less than, 1Ø
The alternative modifiers of the present invention are
a widely diverse group of compounds, including, but not
limited to, certain 'simple carboxylic acid esters, oximes,
nitriles, ketones, amides (carboxamides, sulfonamides or
phosphoramides), carbamates, sulfoxides, ureas, and
phosphine oxides, all of which are found to be efficient
modifiers for aldoxime extractant reagents in the process
of extracting copper values from aqueous solutions,
particularly copper containing acid leach solutions.
The present invention accordingly has several aspects.
Firstly, the invention is concerned with the reagent
composition comprised of the water-insoluble aldoxime
extractant formulated with at least one of the equilibrium

CA 02213102 2007-05-17
modifiers noted earlier, optionally with a kinetic
additive. Secondly, the reagents are formulated with
organic solvent solution of water-insoluble, water
immiscible aliphatic or aromatic solvents for use in a
5 process for the recovery of a metal, preferably copper from
aqueous solutions, typically acid solutions, which process
comprises:
(1) contacting the metal-containing aqueous solution
with an organic phase comprising the water
10 immiscible solvent solution of the reagent
composition to extract at least a portion of the
metal values from the aqueous solution in to the
organic phase;
(2) separating the resultant metal pregnant organic
phase (0) from the resultant metal barren aqueous
phase (A); and
(3) recovering the metal value from the metal
pregnant organic phase.
A wide variety of essentially water-immiscible liquid
hydrocarbon solvents can be used in the copper recovery
process of the present invention. These include aliphatic
and aromatic hydrocarbons such as kerosene, benzene,
toluene, xylene and the like. A choice of essentially
water-immiscible liquid hydrocarbon solvents, or mixtures
thereof for commercial operations will depend on a number
of factors, including the plant design of the solvent
extraction plant (mixer-settler units, Podbielnak
extractors) and the like. The preferred solvents for use
in the recovery process of the present invention, are the
aliphatic and aromatic hydrocarbons having flash points of
130 degrees Fahrenheit and higher, and preferably at least
150 , and solubilities in water of less than 0.1% by
weight. The solvents are essentially chemically inert.
Representative commercial available solvents are Chevron
ion exchange solvent (available from Standard Oil of
California, having a flash point 195 F, Escaid~100 and 110
(available from Exxon-Europe having a flash point of

CA 02213102 2007-05-17
11
TM
180 F), Norpar 12 (available from Exxon-USA, flash point
TM
160 F), Conoco-C1214 (available from Conoco, flash point
160 F), Aromatic 150 (an aromatic kerosene available from
Exxon-USA, flash point 150 F), and the other various
kerosene and petroleum fractions available from other oil
companies.
In the process of the present invention, the organic
solvent solutions will preferably contain from about 0.005
up to about 75% by weight of the aldoxime compounds, which
typically will be employed at about 10-15%. Additionally,
volume ratios of the organic:aqueous (0:A) phase will vary
widely since the contacting of any quantity of the aldoxime
organic solution with the copper containing aqueous leach
solution will result in extraction of the copper values
into the organic phase. For commercial practicality,
however, the organic:aqueous phase ratios for extraction
are preferably in the range of about 50:1 to 1:50.
After separation of the organic phase from the aqueous
feed solution containing the copper, the copper is
recovered from the organic phase by contacting the organic
phase with an aqueous acid solution to strip the metal from
the organic phase. Again, for commercial practicality, the
organic:aqueous phase ratios are preferably in the range of
about 50:1 to 1:50, after which the copper is recovered
from the aqueous strip solution by conventional methods,
typically electrowinning or precipitation.
The invention can be further illustrated by means of
the following examples, in which all parts and percentages
are by weight unless otherwise indicated. In the examples,
the procedure for screening and evaluating the modifiers
was as follows:
Degree of Modification
Definition:
The "degree of modification" is defined as the inverse
ratio of (a) the stripped solvent copper concentration
of an aldoxime extractant at equilibrium (g/1 Cu)

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12
extracted from an aqueous solution containing 30 g/l
Cu, 150 g/l H2S04 to (b) the stripped solvent copper
concentration of the same extractant under the same
conditions when a selected equilibrium modifier is
present.
Apparatus/Eauipment:
1. Analytical balance capable of weighing to 0.1
mg.
2. Separatory funnels, 30 or 60 ml.
3. Volumetric flasks 21 & 100 ml.
4. Pipettes, 25 ml, 10 ml.
5. Filter paper Whatman iPS phase separation paper
6. Atomic Absorption (AA) Spectrophotometer
7. pH meter
Chemicals and Reagents:
1. Copper sulfate pentahydrate, A.R.
2. Iron sulfate rl-hydrate, A.R.
3. Sulfuric acid, A.R.
4. Escaid 100, Cork
5. (5-nonylsalicylaldoxime) approximately 94% pure
Procedure: Details and Precautions:
A. Reagent Preparation
1. Strip Solution
g/l Cu+3, 150 g/l H2SO4
25 a) Weigh 117.85 gm of
copper sulfate into a
beaker and dissolve in
400 ml D.I. water and
transfer to a 1 liter
30 volumetric flask.
b) Add 150 gm conc. H2 S04
mix and cool to room-
temperature.

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13
c) Dilute to 1 liter with
D.I. water.
d) Measure the copper Make adjustments as
concentration by AA. necessary to bring
Titrate with standardized the concentration
NaOH solution for HZSO4 of copper and H2S04
concentration to within 0.5 gl
of specified
concentrations.
2. Aldoxime Solution
25 w/v % aldoxime in Escaid 100
a) Weigh 265.96 gm of Wash the beaker
aldoxime into a beaker, with Escaid 100.
dissolve in 400 ml Escaid
100 and transfer into a 1
liter volumetric flask.
b) Dilute to=1 liter with
Escaid 100
3. Modifier Solutions Preparation
Solutions are prepared at 0.00, 0.025,
0.100, 0.200 Molar modifier
a) Weigh the appropriate Weigh to 0.001 gm
amount of modifier into of requested
a 100 ml volumetric weight. Record the
flask. actual weight to
0.0001 gm. Recalcu-
late the Molarity
based on the actual
weight to 0.001
M.
b) Pipette 25 ml of 25 Allow the pipette
w/v % aldoxime into to drain
the volumetric flask. thoroughly.
c) Dilute to 100 ml with Mix
Escaid 100. thoroughly.
4. Feed Solution
6 g/l Cu, 3 g/l Fe, pH 2.0
a) Weigh 23.58 gm of CuSO4 Mix on a magnetic
= 5 H20 and 14.25 gm of stirrer until
Fe 2 SO4 = nHZO into a everything has
beaker and dissolve in dissolved.
500 ml D.I. water.

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14
b) Transfer to a 1 liter Mix thoroughly.
volumetric flask and
dilute to 1 liter with
D.I. water.
c) Analyze by AA for copper Adjust as required
and iron to correct copper
and iron content
content 0.05 g/1.
d) Measure the pH. pH should be 0.02
units of 2.00. Use
conc. HZSO4 to
adjust pH if neces-
sary. Analyze and
readjust .....
if needed.
B. Analysis
1. Strib Point DO-termination
a) Pipette 10 ml of strip Can use a graduate
solution and 10 ml of instead of a
modifier solution into pipette.
a 30 or 60 ml separatory
funnel.
b) Shake for 3 minutes and
let phases separate.
c) Drain aqueous phase and
add 10 ml of fresh strip
solution.
d) Repeat from b) above for
a total of three contacts
with fresh strip solution.
e) Filter the organic phase
through 1PS paper.
f) Analyze the organic for
copper concentration via
AA.
2. Max. Load
a) Pipette 10 ml of feed
solution and 10 ml modifier
solution into a 30 or 60 ml
separatory funnel.
b) Shake for 3 minutes.

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c) Drain the aqueous phase.
d) Add 10 ml fresh feed.
e) Repeat from b) above for
a total of three contacts
5 with fresh feed solution.
f) Filter the organic phase
through 1PS paper.
g) Analyze the organic for
copper and iron concen-
10 tration via AA.
C. Reoorting Results
1. Calculate the degree of modification by dividing
the strip point copper concentration by the strip
point copper concentration of the Aldoxime alone.
15 2. Plot the molarity of the modifier vs the strip
point copper values.
3. Plot the molarity of the modifier vs the max load
points for copper and iron.
Example 1
1) The extraction isotherm point was determined by
shaking 50 ml of fresh organic (0.188 M 5-
nonylsalicylaldoxime and the indicated amount of
modifier dissolved in Escaid 200, an aliphatic
kerosene) with 50 ml of an aqueous feed solution
containing 6 gpl of copper and 3 gpl of iron (III) as
the sulfates with a pH of 1. 9 for 3 0 minutes. The
phases were separated, the organic was filtered, and
then the copper content of the loaded organic phase
was determined by atomic absorption spectroscopy.
2) The strip isotherm point was determined by shaking 25
ml of the loaded organic from point 1) above with 25
ml of a strip aqueous phase containing 30 gpl of
copper and 170 gpl of sulfuric acid for 30 minutes.

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16
The phases were separated, the organic was filtered,
and then the copper content of the stripped organic
phase was determined by atomic absorption
spectroscopy.
3) The net copper transfer is the difference between the
extraction isotherm point and the strip isotherm
point.
The net copper transfer effects of varying modifier
and modifier concentration for a variety of modifiers can
be seen from the following Table 1, in which nonylphenol,
isotridecanol and tributylphosphate are included for
comparison.

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17
Table 1
Effects of Varying Modifier and Modifier Concentration
Modifier Mole Ratio Extracti) StripZ) Net3)
(Modifier/ [Cu] [Cu] Cu
Aldoxime) (gpl) (gpl) Transfer
(gpl)
None ---- 5.02 3.06 2.0
Nonyiphenol 0.5 4.90 2.34 2.58
0.75 4.75 2.23 2.52
1.50 4.63 1.55 3.08
Isotridecanol 0.5 4.69 1.85 2.84
1.0 4.38 1.40 2.98
Methyl 0.25 4.81 2.56 2.25
Iso-octanoate 0.50 4.88 2.24 2.64
1.0 4.60 1.68 2.92
1.~5 4.38 1.29 3.09
Isodecyl Acetate 0.25 4.90 2.59 2.31
0.50 4.67 2.30 2.37
1.00 4.34 1.59 2.75
1.50 4.30 1.11 3.19
Dodecylaceto- 0.25 4.72 2.60 2.12
phenone Oxime 0.50 4.72 2.48 2.26
Oleonitrile 0.25 4.78 2.22 2.56
0.60 4.45 1.59 2.86
0.75 4.14 1.61 2.83
1.00 4.12 0.92 3.20
Isobutyl Heptyl 0.25 4.81 2.73 2.08
Ketone 0.50 4.80 2.50 2.30
1.03 4.75 2.05 2.70
NIN-Dimethyliso- 0.25 4.28 1.73 2.56
octanamide 0.50 3.70 0.94 2.76
0.75 3.16 0.40 2.76
N-tolyl Tridecyl- 0.25 4.62 2.25 2.37
carbamate 0.60 4.28 1.55 2.73
0.75 4.01 1.20 2.81
Di-2-ethylhexyl 0.078 4.73 2.50 2.23
Sulfoxide 0.16 4.41 2.10 2.31
0.24 4.01 1.65 2.36
0.60 3.48 1.03 2.45
Tributylphosphate 0.125 4.50 2.37 2.12
Decyltoluene- 0.25 4.65 2.22 2.43
sulfonamide 0.60 4.60 1.85 2.75
1.0 4.15 1.25 2.90

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Table 2, below, illustrates the net copper transfer as
well as the degree of modification for a number of modifier
additives.
Table 2
Modifier Molarity Strip Net Deg. of
Additive Point Tran- Mod.
sfer
None 0.000 2.870
Isobutyl iso- 0.026 2.853 3.13 0.994
octanoate 0.100 2.350 3.59 0.819
0.200 1.868 3.98 0.651
bis-2-Ethylhexyl 0.025 2.231 3.61 0.777
urea 0.100 1.250 4.42 0.436
0.201 0.611 4.77 0.213
N-propyl isotri- 0.025 2.575 3.35 0.897
decylcarbamate 0.100 1.601 4.17 0.558
0.200 0.801 4.61 0.279
N,N-bis-2-Ethyl- 0.026 2.275 3.64 0.793
hexylversatamide* 0.104 0.863 4.74 0.301
0.208 0.223 4.81 0.078
Isotridecanol 0.024 2.602 3.34 0.907
0.125 1.683 4.05 0.586
0.250 1.027 4.68 0.358
*amide of Vesaticn acids - a mixture of highly branched, mainly
tertiary monocarboxylic acids having an average of 10 carbon atoms,
a boiling range of 140 C-162 C at 20 min, and a flash point of 120 C.
(C.O.C.).
Example 2
In substantially the same manner as Example 1, a
number of modifier compounds were screened and evaluated
for the effects of varying modifier concentrations which
can be seen from Table 3 below. The modifier screening
procedure in the interim was as follow:
REAGENTS
Strip solution: 30 g/l CU. 150 g/1 HZSOy in D.I. water.
Extraction solution: 6 g/l Cu, 6 g/l Fe, pH 1.50 in D.I
water.

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19
PROCEDURE
Escaid 100 solutions of 0.176 molar DSAdO and modifier were
prepared. The modifier levels tested were 0.025, 0.075,
0.10, and 0.20 molar. Each modifier solution and one
additional solution containing only 0.176 molar DSAdO were
tested as follows:
STRIP POINT
ml of the modifier solution was contacted three times
for 3 minutes each with 10 ml of fresh strip solution. The
10 resulting stripped organic was filtered through Whatman 1
PS paper and assayed for g/l Cu.
EXTRACTION POINT
5 ml of the above stripped organic was contacted one time
for five minutes with 5 ml of extraction solution. The
resulting loaded organic was filtered through 1 PS paper
and assayed for g/l Cu.
CALCULATIONS
Degree of Modification - Divide g/l Cu in stripped
organic by g/l Cu in
unmodified stripped organic
solution.
Net Transfer - Subtract g/1 Cu in stripped
organic from g/l Cu in
loaded organic.
Most of the modifier compounds were available
commercially; however, the carboxylic acid amides,
carboxylic acid esters, the di-2-ethylhexyl sulfoxide, the
alkyl carbonates, nonyl anisole, acetophenome oxime, oleo
nitrile, benzyl-2-butoxy ethyl ether, benzyl 2-(2-
butoxyethoxy) ethyl ether and the amine salts had to be
prepared, though the amines and quarternary amines from
which the salts were prepared were commercially available

CA 02213102 1997-08-14
WO 96/25525 PCTIUS96101116
from Henkel Corporation. The preparation of these modifier
compounds follow Table 3.
Table 3
Effects of Va in Modifier and Modifier Concentration
5 Class Modifier Molar Extract Strip Net
Ratio [Cu] [Cu] Cu
Modifier/ (gpl) (gpi) Transfer
(Supplier) Aidoxime (gpf)
None 5.12 2.87 2.25
Alcohol Isotridecanol 0.142 4.98 2.53 2.45
0.426 4.63 1.88 2.75
0.568 4.51 1.65 2.86
(Exxon) 1.136 3.96 0.99 2.97
Alcohol Terpineo1101 0.142 4.96 2.46 2.50
0.426 4.68 1.94 2.74
0.568 4.53 1.73 2.80
(Hercules) 1.136 3.96 1.07 2.89
Ester 2,2,4-Trimethyl-1,3- 0.142 4.96 2.38 2.58
pentanedioi 0.426 4.70 1.90 2.80
diisobutyrate 0.568 4.56 1.70 2.86
1.136 4.11 1.09 3.02
(Kodak)
Ester Santicizer 97 0.142 4.98 2.36 2.62
(Diaikyl adipate) 0.426 4.63 1.82 2.81
0.568 4.52 1.60 2.92
(Monsanto) 1.136 4.07 1.00 3.07
10 Ester Dibutyl adipate 0.142 4.85 2.30 2.55
0.426 4.61 1.78 2.83
0.568 4.50 1.58 2.92
(Henkel KGaA) 1.136 4.06 0.98 3.08
Ester Mixed adipates 0.142 4.80 2.18 2.62
0.426 4.38 1.52 2.86
0.568 4.24 1.28 2.96
(Dur)ont) 1.136 3.46 0.69 2.77
Ester Diisobutyl adipate 0.142 4.95 2.38 2.57
0.426 4.66 1.84 2.82
0.568 4.53 1.60 2.93
(Duoont) 1.136 4.04 1.00 3.04
Ester fsobutyl 0.142 4.96 2.43 2.53
isooctanoate 0.426 4.84 2.14 2.70
0.568 4.80 2.01 2.79
1.136 4.52 1.54 2.98

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21
Effects of Va in Modifier and Modifier Concentration
Class Modifier Molar Extract Strip Net
Ratio [Cu] [Cu] Cu
Modifier/ (gpl) (gpl) Transfer
Su lier Aldoxime (gpi)
Ester 1,4-Butanediol 0.142 4.93 2.28 2.65
dihexanoate 0.426 4.62 1.76 2.86
0.568 4.50 1.55 2.95
1.136 4.08 0.96 3.12
Ester 1,6-Hexanediol 0.142 4.92 2.27 2.65
dihexanoate 0.426 4.60 1.71 2.89
0.568 4.47 1.50 2.97
1.136 3.96 0.87 3.09
Ester Methyl decanoate 0.142 5.02 2.55 2.47
0.426 4.89 2.25 2.64
0.568 4.83 2.11 2.72
1.136 4.57 1.69 2.88
Ester 2-Pentyl octanoate 0.142 4.97 2.49 2.48
0.426 4.83 2.17 2.66
0.568 4.75 2.02 2.73
1.136 4.55 1.66 2.89
5 Ester n-Hexyl hexanoate 0.142 5.09 2.50 2.59
0.426 5.02 2.18 2.84
0.568 4.90 2.04 2.86
1.136 4.65 1.56 3.09
Ester bis-2-Ethoxyethyl 0.142 4.78 2.07 2.71
Ether adipate 0.426 4.20 1.28 2.92
0.568 4.00 1.02 2.98
1.136 2.81 0.48 2.33
Ester EKTASOLVE DB 0.142 4.87 2.31 2.56
Ether Acetate 0.426 4.51 1.65 2.86
0.568 4.36 1.37 2.99
(Kodak) 1.136 3.77 0.79 2.98
Ester Benzoflex 9-88 0.142 4.95 2.38 2.57
Ether Dipropylene glycol 0.426 4.68 1.87 2.81
dibenzoate 0.568 4.56 1.67 2.89
(Velsicol) 1.136 4.12 1.09 3.03
Ester Benzoflex 400 0.142 4.88 2.29 2.59
Ether Polypropylene glycol 0.426 4.56 1.66 2.90
dibenzoate (x=3) 0.568 4.38 1.44 2.94
(Velsicol) 1.136 3.74 0.81 2.93

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22
Effects of Va in Modifier and Modifier Concentration
Class Modifier Molar Extract Strip Net
Ratio [Cu] [Cu] Cu
Modifier/ (gpl) (gpl) Transfer
Su lier Aldoxime (gpl)
Ester Benzoflex 284 0.142 4.98 2.48 2.50
Ether Propylene glycol 0.426 4.81 2.14 2.67
dibenzoate 0.568 4.75 1.99 2.76
(Velsicol) 1.136 4.47 1.53 2.94
Ester Benzoflex P-200 0.142 4.53 1.99 2.54
Ether Polypropylene 0.426 3.58 1.14 2.44
glycol dibenzoate 0.568 2.82 0.81 2.01
(x=4) 1.136 1.52 0.33 1.19
(Velsicol)
5 Ether Diphenyl oxide 0.25 4.80 2.93 1.87
(Aldrich) 0.50 4.93 2.87 2.06
Ether Nonyl anisole 0.25 4.90 3.03 1.87
0.50 4.85 3.00 1.87
0.75 4.82 3.00 1.87
Ether Benzyl 2-(2-butoxy- 0.142 4.84 2.23 2.61
ethoxy)ethyl ether 0.426 4.42 1.54 2.88
0.568 4.18 1.24 2.94
1.136 3.51 0.63 2.88
Ether Benzyl 2-butoxy- 0.142 4.87 2.37 2.50
ethyl ether 0.426 4.64 1.90 2.74
0.568 4.55 1.76 2.79
1.136 4.17 1.20 2.97
Carbonate 2-Ethylhexyl 0.142 4.81 2.27 2.54
carbonate 0.426 4.71 2.07 2.64
0.568 4.68 1.96 2.72
1.136 4.50 1.63 2.87
Carbonate lsotridecyl 0.142 4.85 2.28 2.57
carbonate 0.426 4.67 2.03 2.64
0.568 4.70 1.94 2.77
1.136 4.45 1.58 2.86
Carbonate Lorol C8/C10 0.142 4.82 2.29 2.53
carbonate 0.426 4.70 2.04 2.66
0.568 4.66 1.95 2.71
1.136 4.48 1.58 2.91
Carbonate Isobutyl carbonate 0.142 5.06 2.58 2.48
0.426 4.94 2.32 2.62
0.568 4.88 2.20 2.68
1.136 4.67 1.78 2.89

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Effects of Va in Modifier and Modifier Concentration
Class Modifier Molar Extract Strip Net
Ratio [Cu] [Cu] Cu
Modifier/ (gpl) (gpl) Transfer
Su lier Aldoxime (gpl)
Ketone Isobutyl heptyl 0.142 5.07 2.57 2.50
ketone 0.426 4.94 2.26 2.68
0.568 4.88 2.11 2.77
1.136 4.61 1.62 2.99
Kodak
Ketone Mixed higher 0.142 4.95 2.47 2.48
ketones 0.426 4.62 1.97 2.65
0.568 4.51 1.76 2.75
(Union Carbide) 1.136 3.93 1.13 2.80
Ketone Distilled mixed 0.142 4.98 2.48 2.50
higher ketones 0.426 4.80 2.16 2.64
0.568 4.79 2.05 2.74
(Union Carbide) 1.136 4.47 1.56 2.91
Ketone C11 ketone 0.142 4.96 2.51 2.45
0.426 4.78 2.11 2.67
0.568 4.68 1.92 2.76
(Kodak) 1.136 4.29 1.39 2.90
5 Ketone 5,8- 0.142 5.14 2.70 2.44
Diethyidodecane- 0.426 5.10 2.52 2.58
6,7-dione 0.568 5.04 2.36 2.68
1.136 4.94 2.19 2.75
Nitrile Undecyl cyanide 0.142 5.00 2.55 2.45
0.426 4.81 2.28 2.53
0.568 4.80 2.15 2.65
(Aldrich) 1.136 4.17 1.72 2.45
Nitrile C21 Dinitrile 0.142 4.96 2.37 2.59
0.426 4.69 1.86 2.83
0.568 4.62 1.68 2.94
1.136 4.17 1.09 3.08
Nitrile DN523 0.142 4.98 2.42 2.56
C36 Dinitrile 0.426 4.74 1.87 2.87
0.568 4.62 1.67 2.95
(Henkel Corp.) 1.136 4.20 1.10 3.10
Carbamate N-Octyl isotridecyl- 0.142 4.86 2.23 2.63
carbamate 0.426 4.38 1.59 2.79
0.568 4.14 1.32 2.82
1.136 3.42 0.63 2.79

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Effects of Va in Modifier and Modifier Concentration
Class Modifier Molar Extract Strip Net
Ratio [Cu] [Cu] Cu
Modifier/ (gpl) (gpl) Transfer
Su tier Atdoxime (gpl)
Amide N, N'-bis-2- 0.142 4.73 1.95 2.78
Ethylhexyl urea 0.426 4.36 1.25 3.11
0.568 4.19 1.04 3.15
1.136 3.77 0.65 3.12
Amide N, N-bis-2- 0.136 2.44
Ethylhexyl 2- 0.543 1.18
eth Ihexanamide 1.087 0.32
Amide N-Hexyl 2- 0.142 4.68 2.08 2.60
ethylhexanamide 0.426 4.12 1.31 2.81
0.568 3.91 1.09 2.82
1.136 3.15 0.45 2.70
Amide N,N-Dibutyl 2- 0.142 4.66 2.12 2.54
ethythexanamide 0.426 3.86 1.24 2.62
0.568 3.55 0.90 2.65
1.136 2.32 0.17 2.15
5 Amide N,N-Dibutyl 0.142 4.89 2.24 2.65
benzamide 0.426 4.14 1.31 2.83
0.568 3.80 0.94 2.86
1.136 2.76 0.22 2.54
Amide N,N-Dibutyl 0.136 2.50
octanamide 0.543 1.13
1.087 0.25
Phosphate Trioctylphosphate 0.142 4.63 2.16 2.47
0.426 3.65 1.20 2.45
0.568 3.21 0.82 2.39
(ALFA Products) 1.136 1.88 0.10 1.78
Mixture 1/2 molar ratio 0.142 4.95 2.48 2.47
Trioctyiphosphate/ 0.426 4.76 2.12 2.64
Nonylphenol 0.568 4.70 1.96 2.74
1.136 4.41 1.49 2.92
Mixture 1/1 molar ratio 0.142 4.91 2.40 2.51
Trioctylphosphate/ 0.426 4.61 1.90 2.71
Nonylphenol 0.568 4.45 1.69 2.76
1.136 3.93 1.09 2.84
Mixture 2/1 molar ratio 0.142 4.82 2.31 2.51
Trioctyl- 0.426 4.32 1.67 2.65
phosphate/Nonyl- 0.568 4.10 1.42 2.68
phenol 1.136 3.21 0.65 2.56

CA 02213102 1997-08-14
WO 96125525 PCTIUS96101116
Effects of Vaging Modifier and Modifier Concentration
5 Class Modifier Molar Extract Strip Net
Ratio [Cu] [Cu] Cu
Modifier/ (gpl) (gpi) Transfer
Su lier Aidoxime (gpi)
Mixture 2/1 molar ratio 0.142 4.82 2.31 2.51
Trioctyl- 0.426 4.32 1.67 2.65
phosphate/Nonyl- 0.568 4.10 1.42 2.68
phenol 1.136 3.21 0.65 2.56
Mixture 1/2 molar ratio 0.142 4.77 2.27 2.50
lsotridecanol/ 0.426 4.04 1.45 2.59
Trioctylphosphate 0.568 3.70 1.12 2.58
1.136 2.58 0.32 2.26
Mixture 1/1 ratio 0.142 4.84 2.31 2.53
lsotridecanol/ 0.426 4.22 1.59 2.63
Trioctylphosphate 0.568 3.92 1.29 2.63
1.136 2.97 0.49 2.48
Mixture 2/1 ratio 0.142 4.93 2.36 2.57
lsotridecanol/ 0.426 4.40 1.71 2.69
Trioctylphosphate 0.568 4.16 1.45 2.71
1.136 3.40 0.71 2.69
5 Mixture 1/2 ratio Diisobutyl 0.142 4.87 2.33 2.54
adipate/Isotri- 0.426 4.63 1.83 2.80
decanol 0.568 4.52 1.65 2.87
1.136 4.03 1.02 3.01
Mixture 1/1 ratio Diisobutyl 0.142 4.89 2.29 2.60
adipate/isotri- 0.426 4.64 1.82 2.82
decanol 0.568 4.51 1.61 2.90
1.136 4.02 1.00 3.02
Mixture 2/1 ratio Diisobutyl 0.142 4.88 2.29 2.59
adipate/Isotri- 0.426 4.64 1.80 2.84
decanol 0.568 4.55 1.61 2.94
1.136 4.05 0.99 3.06
Salt 1/1 moiar ratio 0.142 4.37 1.93 2.44
Aliquat 3361 0.426 3.30 0.91 2.39
Dinonylnapthalene 0.568 2.88 0.58 2.30
sulfonic acid 1.136 1.71 0.08 1.63
Salt Alamine 0.14 4.20 1.83 2.37
308/Toluene- 0.28 3.34 1.07 2.27
sulfonic acid 0.42 2.69 0.59 2.10
10 Salt Alamine 0.14 4.32 1.96 2.36
336/Toluene- 0.28 3.50 1.24 2.27
sulfonic acid

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The foregoing Tables and compounds exemplified
therein, evaluated as modifiers with (5-nonyl
salicylaldoxime) as the extractant in kerosene solution
(Escaid 100) for the extraction of copper from aqueous acid
solutions containing copper, clearly illustrate a large
number of compounds which may be employed as modifiers for
an aldoxime extractant.
As can be seen therefrom, a number of compounds
provide for net copper transfer at least equivalent to
those employed in the past, such as nonylphenol, tridecanol
and tributyl phosphate, while others provide for a
significant increase in the net copper transfer. It can be
seen that in the absence of any modifier, with a degree of
modification of 1.0, a net copper transfer of 2.0 g/1
results. The nonylphenol and tridecanol employed in the
past, which are included in the Tables for comparison
resulted in an increase in the net copper transfer up to
about 3 g/l copper, employing the modifier in amounts of
about 0.5 to about 1.5 moles of modifier per mole of
aldoxime. The tributylphosphate, however, showed only a
small increase in the net copper transfer. In contrast,
many of the compounds of the present invention showed net
copper transfer increases to above 3.0, and even exceeding
4.0 g/l at molarities varying from about 0.02 to about 0.25
with degrees of modification from about 0.2 up to about
0.95. In general, the mole ratio of modifier/aldoxime will
typically vary from about 0.2 to about 1.5, preferably from
about 0.5 to about 1.2. The degree of modification will
vary dependent on the particular modifier and aldoxime
employed as the extractant. Typically however, the degree
of modification as defined herein will vary between about
0.25 and approach 1.0, i.e., up to about 0.99, and
preferably within the range of about 0.3 to about 0.9.
From Table 3 in particular, it can be seen that
suitable modifiers fall within a variety of diverse classes
of compounds, such as, alcohols and esters, polyethers,

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ester-ethers, oximes, ketones, nitriles, carbamates,
amides, and salts of certain amine (trialkyl amines) and
quaternary ammonium compounds, which modifier compounds
contain aliphatic, aromatic or araliphatic groups having
from about 4 to about 36 carbon atoms, the total number of
carbon atoms in the compounds being sufficient to render
the compounds water insoluble and soluble in the water
insoluble and water immiscible hydrocarbon solvents
employed for use with the water insoluble aldoxime.
Excluded from the scope of the present invention are
alcohol and ester classes of modifier compounds such as
tridecanol, and those long chain branched alcohols and
esters having up to 30 carbon atoms with a ratio of methyl
groups to non-methyl groups above 1:5. It should be
understood however, that the modifier compounds of the
present invention may, if desired, be employed admixed with
the modifiers employed in the past, such as phenols,
tridecanol and other fatty alcohols and tributylphosphate,
the highly branched alcohols or esters having a ratio of
methyl to non-methyl groups above 1:5.
For the purposes of the present invention, also
excluded from the ether class is nonyl anisole. While,
based on the other ethers exemplified, nonyl anisole might
be expected to be useful as a modifier, as can be seen from
Table 3 in particular, nonyl anisole appears to have an
adverse effect on net copper transfer, showing a net copper
transfer of only. 1.87 g/1 at mole ratios of modifier to
aldoxime from 0.25 to 0.75, thus being substantially
ineffective in view of the fact that the absence of any
modifier resulted in a net copper transfer of 2.0 g/l.
This does serve to illustrate however the unpredictability
from one compound to another as to its utility as a
modifier for aldoxime extractants in the process of
recovery of copper from aqueous solutions containing
copper, particularly aqueous acid solutions.
As indicated earlier, many of the compounds evaluated
herein are commercially available and suppliers of many of

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compounds in the various classes as described in the
following examples 3 through 16.
Example 3
(Preparation of Carboxylic Acid Amides)
The carboxylic acid amides were synthesized by a
typical Schotten-Baumann type procedure. The desired
starting amine (0.8 mole) and triethylamine (0.8 moles)
were placed in a one liter round bottom flask fitted with
a mechanical stirrer, addition funnel, and thermometer.
The mixture was stirred and the corresponding carboxylic
acid chloride (0.6 moles) added over a period of 30
minutes. Toluene was added as needed to keep the reaction
mixture stirrable. The,temperature was allowed to rise to
85 C. After addition was complete, the reaction mixture was
allowed to stir for an additional 1-2 hours. The mixture
was then cooled, washed three times with equal volumes of
5% by weight aqueous sodium bicarbonate solution and then
three times with equal volumes of water. The product was
then distilled under vacuum. The heartcut was identified
by IR and NMR spectroscopy.
Example 4
(Preparation of Carboxylic Acid Esters)
The carboxylic acid esters were prepared by a strong
acid catalyzed condensation of the carboxylic acid with the
alcohol. The carboxylic acid (0.7 moles), alcohol (0.85
moles), p-toluenesulfonic acid (0.5 g) and toluene (25 ml)
were placed in a 500 ml round bottom flask fitted with a
stirrer and a Dean Stark trap for water removal. The
reaction mixture was heated to ref lux and then held at
reflux until the theoretical amount of water had been
collected. The reaction mixture was then cooled, washed
twice with 5% by aqueous sodium carbonate and twice with
water. The crude product was then fractionally distilled

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under vacuum. The heartcut was collected and its identity
confirmed by IR and NMR spectroscopy.
Example 5
(Di-2-Ethylhexyl sulfoxide)
The starting sulfide was prepared by the reaction of
2-ethylhexyl chloride with sodium sulfide (See Reid,
"Organic Chemistry of Bivalent Sulfur", Vol. 2, pp 16-21,
24-29, and Vol 3, pp 11-14 (1960)). The di-2-
ethylhexylsulfide (0.775 moles) and acetone (1500 ml) were
then placed in a magnetically stirred flask and 30%
hydrogen peroxide added over a period of 10 minutes. The
reaction mixture was allowed to stir at room temperature
for 48 hours. A 10% 'ay weight aqueous solution of sodium
bisulfite (350 ml) was then added to the flask along with
350 ml of water. The resultant mixture was extracted with
ether. The ether extract was washed with water, then
saturated sodium chloride solution, dried and evaporated to
a clear oil. IR analysis established that oxidation was
not complete and the entire procedure was repeated. The
final product was judged to be of high quality based on IR
analysis.
Example 6
(Preparation of Alkyl Carbonates)
The alkyl carbonates were prepared by
transesterification of dimethyl carbonate with a higher
molecular weight alcohol. A mixture of the alcohol (4.1
moles), dimethyl carbonate (2.0 moles) and potassium
carbonate (0.84 g) was heated to reflux and the methanol
was slowly distilled.away. The excess alcohol and unreacted
= 30 dimethyl carbonate were then removed under vacuum and the
product distilled under vacuum. The product was
identified by IR and NMR spectroscopy.

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Example 7
(Preparation of Salts)
The amines, Alamine 308 (trioctyl amine) or 336
(trialkyl amine having C8, C,o groups) available from Henkel
5 Corp., were dissolved in kerosene and an equimolar amount
of p-toluenesulfonic acid, available from Aldrich, was then
added. The salt settled out as a thick oil which was then
used to make up the test solutions. The salt of Aliquat
336 (methylquat of Alamine(D 336), available from Henkel
10 Corp, with dinonylnapthalenesulfonic acid, available from
Pfaltz and Bauer, was prepared by mixing equivalent amounts
of the Aliquat 336 with the acid in kerosene and washing
with dilute sodium bicarbonate solution.
Example 8
15 (Nonyl Anisole)
Nonyl anisole was prepared from nonylphenol, available
from Jefferson Chemicals, and methyl iodide under typical
Williamson ether synthesis conditions. Nonylphenol (1.0
mole), methyl iodide (1.2 moles), potassium carbonate (1.25
20 moles) and acetone were placed in a round bottom flask and
heated to reflux. After refluxing overnight, the reaction
mixture was poured into water and extracted with ether.
The ether extract was washed with saturated sodium chloride
solution, dried and evaporated to an oil which was then
25 purified by vacuum distillation. The product was analyzed
as nonyl anisole by IR and NMR spectroscopy.
Example 9
(Dodecylacetophenone Oxime)
Dodecylacetophenone oxime was prepared as described in
30 European patent Application 557274.

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Example 10
(Preparation of C21 Dinitrile)
A mixture of 500 g of C21 diacid from Westvaco, 3.0 g
of zinc oxide and 3 g of water was charged to a 1.5 liter
reactor and heated to 150 C. Anhydrous ammonia was
sparged through the hot mixture. The temperature was
raised to 295-300 C with continuous sparging with ammonia.
The reaction mixture was kept at these conditions for a
total of 9 hours during which time about 125 ml of aqueous
and organic components were collected in a Dean Stark trap.
An additional 5.0 g of zinc oxide was added and the mixture
distilled. Fraction I, BP 150-195 C @ 0.6-0.95 mm,
weighed 78 g. Fraction II, BP 195-215 C @ 0.65 mm,
weighed 177 g. Both fractions were considered by GC/IR to
be a mixture of isomeric nitriles which were free of
carboxylic acids.
Example 11
(Oleonitrile)
Oleonitrile was prepared from oleic acid in same
fashion as was the C-21 dinitrile above.
Example 12
(Preparation of Benzyl 2-Butoxyethyl Ether)
A mixture of 8.1 g of 60% sodium hydride (0.2 moles)
in mineral oil, 20 ml of toluene and 100 ml of
tetrahydrofuran was prepared. To this 23.6 g of 2-
butoxyethanol (0.2 moles) was added over a 5 minute period
of time. The resultant mixture was heated at reflux
temperature for one hour after which 25.2 g of
benzylchloride (0.2 moles) was added. The reaction mixture
was heated at reflux temperature for an additional hour.
Any unreacted sodium hydride was destroyed by the addition
of 10 ml of methanol. The cooled reaction mixture was

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diluted with hexane and washed with water. The aqueous
phase was back washed with hexane which was combined with
the first hexane extract and stripped of volatiles at
reduced pressure to leave 44 g of product which contained
about 80% benzyl-2-butoxyethyl ether, 6% 2-butoxyethanol,
7% benzylchloride and 3% methyl benzyl ether. This was
distilled to yield 1.4 g of forecut, BP to 800 C @ 0.6 mm
which was discarded and 34 g of heart cut, BP 800 C @ 0.6
mm. The heart cut was judged to contain about 91% desired
product.
Example 13
(Preparation of Benzyl 2-(2-Butoxyethoxy) Ethyl Ether)
A mixture of 8.25 g of 60% sodium hydride (0.205
moles) in mineral oil, 20 ml of toluene and 100 ml of
tetrahydrofuran was prepared. To this 32.4 g of 2-(2-
butoxyethoxy) ethanol was added over a 5 minute period of
time. The resultant mixture was heated at reflux
temperature for 3.5 hours before all the sodium hydride had
reacted, after which 25.2 g of benzylchloride (0.2 moles)
was added. This mixture was heated at reflux temperature
for an additional hour. Any unreacted sodium hydride was
destroyed by the addition of 10 ml of methanol. The cooled
reaction mixture was extracted with water and the volatiles
removed from the organic phase at reduced pressure to leave
53 g of product which was judged to contain about 841%
benzyl-2-(2-butoxyethoxy) ethyl ether, 3% toluene, 2%
methyl benzyl ether and 3% benzylchloride. This was
distilled to yield 4.9 g of forecut, BP to 90 C @ 0.5 mm
which was discarded and 43.5 g of heart cut, BP 90-98 C @
0.3 mm. The heart cut was judged to be about 97% pure.

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Example 14
(Preparation of Bis-2-Ethylhexylurea)
A mixture of 1,592 g (12.3 moles) of 2-ethylhexylamine
and 261 g (4.35 moles) of urea was heated at reflux
temperature for 24 hr. The mixture was cooled and about
420 g of 2-ethylhexyl amine was removed by distillation at
pot temperatures of 115-200 C/i mm pressure. The residue
was subject to a two pass distillation on a wiped film
evaporator. The first pass produced 112 g of distillate at
200 C/0.3 mbar pressure which was discarded. The residue
was distilled at 230 C/0.25 mbar to produce 1,035 g of
product.
Example 15
(Preparation of 5,8-Diethyldodecane-6,7-Dione)
A mixture of 67 g of 5,8-diethyl-7-hydroxy-6-
dodecanone (acyloin) and 0.5 g of 86% potassium hydroxide
pellets was heated to 185-190 C for 7 hours while air was
bubbled through the system. Analysis by infrared showed
the residue to be about 11% acyloin and 79% 5,8-
diethyldodecane-6,7-dione (diketone).
A mixture of 114 g of acyloin and 2.0 g of 86%
potassium hydroxide pellets was heated to 195-200 C. Air
was bubbled through for 6 hours at that temperature in the
presence of stainless steel screen. Analysis by GC/IR
showed the material to be about 89% diketone and 4%
acyloin.
Two such preparations were combined, diluted with
hexane, washed with alkali then water and stripped of
volatiles at reduced pressure to leave 96 g. This was
distilled through a column packed with rashig rings at 2-5
MM pressure.
Cut I, BP to 135 C, 3.7 G discarded.
Cut II, BP 135-145 C, 60 G; GC/IR showed 1% acyloin
and 92% diketone.

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Cut III 1450 C/i mm pressure, 16 g; GC/IR found 10%
acyloin and 78% diketone.
Example 16
(Preparation of N-n-Octyl Isotridecylcarbamate)
A mixture of 50 g (0.32 mole) of octyl isocyanate, 75
g (0.38 moles) of isotridecyl alcohol, 1.0 ml of pyridine
and 60 ml of toluene was heated at reflux temperature for
20 hours. The volatiles were removed at reduced pressure
to leave 124 g. The residue was distilled at about 1 mm
pressure to produce 16.4 g of forecut BP to 1650 C which
was discarded. The heart cut, at 165 C, produced 106.7 g
of product which was considered to be of very high purity
by IR and NMR analyses.`=
N-tolyl isotridecylcarbamate can be produced in a
similar manner from p-tolyl isocyanate and isotridecyl
alcohol.
ExamAle 17
Earlier in this application, reference was made to the
problem of crud formation in that it is desirable to run
with the minimum amount of modifier necessary to achieve
effective stripping and maximum net copper transfer while
at the same time minimizing crud formation. One potential
way of achieving the foregoing is to use mixtures of
modifiers. Accordingly, mixtures of trioctylphosphate with
either nonylphenol or isotridecanol were evaluated,
following the procedure employed in Example 2. The results
can be seen in Table 4 below and in Figures 1 through 4.

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Table 4
Mixtures of Strong Hydrogen Bond Acceptors with Hydrogen Bond
Donators as Modifiers
5 Modifier Molar Ratio Extract Strip Net Cu
Modifier/ [cu] [Cu] Transfer
Aldoxime (gpl) (gpl) (gpl)
Nonylphenol 0.213 5.0 2.55 2.45
0.426 4.95 2.40 2.55
Trioctylphosphate 0.11 4.75 2.27 2.48
0.213 4.37 1.90 2.47
0.426 3.65 1.20 2.45
Isotridecanol 0.213 4.87 2.3 2.57
0.426 4.63 1.88 2.75
1/1 Nonylphenol/ 0.426 4.60 1.90 2.70
10 Trioctylphosphate
1/1 Isotridecanol/ 0.426 4.22 1.59 2.63
Trioctylphosphate
2/1 Isotridecanol/ 0.340 4.60 1.90 2.70
Trioctyiphosphate
The data for points at molar ratios of 0.11, 0.213 and 0.34
were derived by graphical interpolation of the data in the
graphs in Figures 1 through 4, summarizing the results for
mixtures of trioctylphosphate with either nonylphenol or
isotridecanol. From the Table and the Figures, it can be
seen that a 1:1 mixture of nonylphenol with
trioctylphosphate on a molar basis at a total modifier to
salicylaldoxime molar ratio of 0.426 gives equivalent
performance to isotridecanol at a molar ratio of 0.426.
With the mixture, however, the individual modifier
components are present in a molar ratio of only 0.213. As
can be seen from the data in the Table for the individual
components, it is not an additive effect. Similar effects
can be observed with isotridecanol and trioctylphosphate.
In this case, however, one has to use a 2:1 ratio of
isotridecanol to trioctylphosphate on a molar basis.
Another example of a mixture of modifier is the
mixture of 0.01 molar tertiary amine, Alamine 308/p-
toluene sulfonic acid salt (ptsa) with various levels of
isotridecanol (TDA). The results of the tests in which

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dodecylsalicylaldoxime was kept at 0.176 molar, can be seen
in Tables 5 and 5B below, in which the first two runs Table
5A were made with 0.01 molar Alamine 308/ptsa salt. In
Table 5B, the runs were made without the Alamine 308-ptsa
salt and with no modifier.
Table 5A
TDA Molarity Strip Point Extraction Net Degree
Point Transfer of Mod.
0.0225 2.04 4.58 2.54 0.79
0.045 1.82 4.48 2.66 0.70
Table 5B
Alamine 308 Strip Point Extraction Net Degree
b:olarity Point Transfer of Mod.
0.0125 1.97 4.44 2.47 0.76
0.025 1.43 3.87 2.44 0.55
TDA Molarity
0.075 1.84 4.58 2.74 0.71
No modifier 2.59 4.97 2.38 1.00