3,927,169 Ion exchange process for the recovery of copper

Patent Number/Link:

United States Patent [19]

Goren et al.

[II] 3,927,169

[45] Dec. 16, 1975

[54] ION EXCHANGE PROCESS FOR THE

RECOVERY OF COPPER

[52] U.S. CI. 423/24; 75/101 BE; 252/182

[51] Int. CP C01G 3/00

[58] Field of Search 423/24; 75/101 BE, 117;

260/438.1, 526.5, 539

[75] Inventors: Mayer B. Goren, Denver; Enzo L.

Coltrinari, Arvada, both of Colo.

[73] Assignee: Hazen Research, Inc., Golden, Colo.

[22] Filed: Mar. 11, 1974

[21] App\. No.: 450,058

Primary Examiner-Oscar R. Vertiz

Assistant Examiner-Brian E. Hearn

Attorney, Agent, or Firm-Sheridan, Ross & Fields

Swanson 75/l17

Cook et al. 75/117

Kane et aI... 75/1 0 1 BE

2/1969

5/1972

5/1974

3,428,449

3,666,446

3,810,827

[57] ABSTRACT

A process for recovering copper values from an acidic

aqueous medium which comprises contacting the medium

with an organic solvent having dissolved therein

a copper extraction reagent comprising a 2-hydroxy

benzophenoxime or mixtures thereof and as an extraction

accelerating agent therefor an a-halo carboxylic

acid or a thioglycolic acid or oxidation product of the

latter. The invention includes the compositions comprised

of 2-hydroxy benzophenoximes and the copper

extraction accelerating agents.

17 Claims, 2 Drawing Figures

References Cited

UNITED STATES PATENTS

7/1949 Carson 260/438.1

9/1951 Morway et al... 260/526.5

11/1957 Westfahl 260/526.5

2,475,350

2,567,023

2,812,345

[56]

EFFECT OF REAGENT C3 AND C4 ADDITION TO

10% L1X64N ON COPPER EXTRACTION RATE

::IE

:::l

it:

:::l 80

~ 70

(!) z

0<l 60

...J

!::!

<l 50 (!) a::

0 2 3

OF PASSES

100

u.s. Patent Dec. J6, 1975 Sheet 1 of 2 3,927,169

EFFECT OF REAGENT C3 AND C4 ADDITION TO

10% L1X64N ON COPPER EXTRACTION RATE

100

-:::> L1X64N+C3

0:::

e-n

-....J :::> 80 L1X64N + C4

~ 70

.,.

(!) z-

0 « 60

....J

Z«

50 L1X64N ONLY (!)

0:::

o 1 2

NO. OF PASSES

u.s. Patent Dec. 16, 1975 Sheet 2 of 2 3,927,169

(\J 0

Z f-

0 <I: CJ w

0::: Cf) f-

<I:

0 Q I 0 0 a..

<I: Z

Cl.. U

<:t a..

- Z U 0::: <I: I- 0

(J) cq 0::: 0 C\I

Z 0::: 0 0

<I: w Z ~ a..

If) a..

fJ 0::: (,) 0

(,) W

~ f- a.. Z Z a..

W 0 0 0

~ (,)

<I: Z

W ~ IJ..

0::: 1D 0

IJ.. <;;t:

0 -l -l

0 ......

I- 0 ~ U 0 w 0

W (\J

!:- L- ----:~---___:_:::_-------'0

o mOm 0

(\J Q o 0 0 0

J3S / t:l3ddOJ l/9 31\1t:l 9Nlddlt:llS

3,927,169

ION EXCHANGE PROCESS FOR THE RECOVERY

OF COPPER

BACKGROUND OF THE INVENTION

The solvent extraction process is finding increasing

application in the field of extractive metallurgy. It is

commercially used for the recovery of uranium, copper,

tungsten, molybdenum, rare earths, beryllium, and

other metals. Its wide application is because of the

availability of organic solvents with specifically selective

properties for a given element. The specific organicsolvent

can be used. to extract from an aqueous

solution and purify one metal element from a mixture

containing many contaminants.

The most recent wide use of solvent extraction is for

the recovery of copper from dilute sulfuric acid solutions

such as those obtained by leaching a copper oxide

ore. This use has been made possible principally by the

development of specifically copper selective solvents

such.as the extractants sold by Ashland Chemical Co.

under the trade name Kelex, and those sold by General

Mills Co. under the trade names, LIX 63, LIX 64, LIX

64N and LIX 70, the latter three including substituted

2-hydroxy benzophenoximes as the active extractant.

The copper selective solvent sold under the trade

name LIX 63, an alpha hydroxy oxime, is not operative

in solutions of the acidity normally encountered in acid

leaching while certain other types such as the sulfonates

and organo phosphates are non-selective and thus

have no present use in copper recovery.

The equipment for the application of solvent extraction

to extractive metallurgy has usually consisted of

multiple stage counter-current mixer-settler systems in

which the barren organic solvent and the pregnant

aqueous stream (usually a leach liquor) are mixed together

for a given period of time after which they are

permitted to separate in a settling reservoir. The solvent

and aqueous then flow in opposite directions to

the next stage of contact.

During the mixing step in conventional systems for

copper recovery, the driving force for the transfer of

the copper from the aqueous to the organic phase (or

in the case ofstripping, the transfer from the organic to

the aqu~ous phase) depends upon the difference in

concentration of copper in the aqueous and the organic

phases. If agitated long enough, eventually a chemical

equilibrium is achieved and no further transfer of copper

takes place between the aqueous and the organic.

The concentrations at which equilibrium is reached will

be dependent on the ion exchange agent, the acidity of

the solution, temperature, etc. In order to achieve maximum

efficiency in the system, it is highly desirable to

. have each mixer come as close as possible to this chemical

equilibrium before the material leaves the mixer

and flows to the settling tanks.

The size of the mixing equipment which is required to

achieve chemical equilibrium within a given time will

depend fundamentally on the extraction rate of the

particular ion exchange agent being used. It is known

that those ion exchange agents which have been developed

specifically for the extraction of copper are much

slower in their extraction rate than is the ion exchange

agent used specifically for extraction of some other

metals, as for example, uranium. The extraction of

uranium with a tertiary amine in acid solution of pH 1.5

is very fast, a matter of seconds, whereas the extraction

of copper from acid solution of that pH by LIX 64, (a

2-hydroxy substituted benzophenoxime) is quite slow,

commonly requiring as long as 4 minutes to reach equilibrium

in a batch agitated system at room temperature.

5 Because the solution flow rates in a copper leaching

plant are very large, the size of the mechanically agitated

vessels required for a mixing system to contain

and mix the required solvent and aqueous for this long

a time are large and expensive. In addition, in a contin-

10 uous mixing system it is not possible to achieve the true

chemical equilibrium that·is achieved when materials

are agitated in a batch. This is because of the well

known phenomenon of short circuiting. In fact, as a

practical matter; a mixer designed for continuous cop-

IS per extraction is calculated on the basis of only 80

percent of the extraction equilibrium that would be

achieved in a batch tank having the same residence

time.

The dollar value per unit volume of a copper leach

20 solution containing a few grams per liter of copper is

very low, thus the capital investment for an appropriate

mixing system is quite high for the amount of copper

which is being treated. The depreciation costs, therefore,

per pound of copper are high and this diminishes

25 the value of the solvent extraction process for the copper

industry. Further contributing to the diminished

value of the process is the fact that large amounts of

expensive reagents are tied up for prohibitive times.

Much of this disadvantage would be overcome if it

30 were possible to accelerate the rate of transfer of copper

from an aqueous leach liquor to the ion exchange

agent and its reverse, the stripping of copper from ion

exchange agent into an acid electrolyte. This objective

is achieved by the present invention through which the

35 rate of extraction of copper from an acid solution by

the specified copper extractants, LIX 64, LIX 64N and

LIX 70, is enormously accelerated by the addition of

small quantities of an a-halo carboxylic acid or a thioglycolic

acid or an oxidation product of a thioglycolic

40 acid, the latter three components being referred to

hereinafter as copper extraction accelerating agents.

SUMMARY OF THE INVENTION

The invention relates to the use of the copper extrac-

45 tion acceleration agents as additives to the 2-hydroxy

benzophenoximes represented by the trade name products

LIX 64, LIX 64N and LIX 70 sold by General

Mills, Inc., to greatly increase the rate at which these

latter products extract copper when used as ion ex-

50 change extractants to recover copper from acid solution.

It comprises a method for recovering copper values

from acidic aqueous solutions by contacting the

solution with a water-immiscible organic phase having

a density different from that of the aqueous phase com-

55 prised of an organic solvent having dissolved therein as

an active extractant a 2-hydroxy benzophenoxime or

mixtures thereof with one or more of the extraction

accelerating agents. The invention includes the composition

comprised of 2-hydroxy benzophenoximes and

60 the copper extraction accelerating agents.

DETAILED DESCRIPTION OF THE INVENTION

2-hydroxy benzophenoximes operative for the invention

include those disclosed in U.S. Pat. No. 3,428,449

65 issued to Ronald F. Swanson on Feb. 18, 1969. These

compounds are ion exchange extractants for copper

values in acid solutions. Individual compounds or mixtures

thereof may be used. Methods for making these

3,927,169

H 0 I ~

R-S-C-C-OH k

are CH,,-(CH,)x-S-CH,-C-OH

wherein X is 7-20,

in which R is an aliphatic group, aryl or an araliphatic

60 group.

Representative of the above compounds which are

operative

groups are pentenyl, hexenyl, octenyl, decenyl,

dodecenyl, octadecenyl and the like. It is preferred that

such groups contain less than about 2 double bonds and

more preferably a single double bond. The R" portion

5 of the ether groups can be the saturated and ethylenically

unsaturated aliphatic groups as described above.

The R" portion of the said ether groups is preferably an

alkyl group. In addition, the saturated, ethylenically

unsaturated and ether groups may contain inert substit-

10 uents such as halogen, ester, amide, and the like. Likewise,

the aromatic nuclei can contain inert substituents.

By inert is meant that the said constituents do not affect

the solubility, stabiliity or extraction efficiency of the

compounds to any significant extent.

15 The benzophenoximes, which may be used in the

present invention, are those which have sufficient solubility

in one or more of the solvents disclosed below or

mixtures thereof to make about a 2% solution and

which are essentially insoluble or immiscible with wa-

20 ter. At the same time, the benzophenoxime should

form a complex with the metal, such as copper, which

complex, likewise, is soluble in the organic solvent to at

least the extent of about 2% by weight. These characteristics

are achieved by having alkyl, ethylenically

25 unsaturated aliphatic or ether substituents as described

on either ring. It is necessary to have substituents which

total at least 3 carbon atoms. This minimum may be

obtained by means of a total of 3 methyl groups distributed

on either one or on the two rings, by means of a

30 methyl and an ethyl group, by means of a propyl group,

etc. Usually it is prefered not to have more than 25

carbon atoms total in the substituents since these substituents

contribute to the molecular weight of the

oxime without improving operability. Large substitu-

35 ents, therefore, increase the amount of oxime for a

given copper loading capacity. In general, the branched

chain alkyl substituents effect a greater degree of solubility

of the reagent and of the copper complex and,

40 accordingly, these are preferred.

The 2-hydroxy benzophenoximes are suitable as a

copper ion exchange extractant component of the

mixed ion exchange reagent of the present invention

which includes at least one of the copper extraction

45 accelerating agents as the other component. Aliphatic

substituted thioglycolic acids and oxidation products

thereof, and a-halo substituted aliphatic carboxylic

acids are used as representative members of the extraction

accelerating agents to illustrate the· invention.

50 The thioglycolic acids which are operative as copper

extracting accelerators for the LIX compounds are

represented by the following formula:

OH NOH

O/ -cII -O

OH NOH

o-[~-o

/- "R.

R n

in which Rand R' may be individually alike or different

and are saturated aliphatic groups, ethylenically unsaturated

aliphatic groups or saturated or ethylenically

unsaturated ether groups (i.e. -OR") and m and n are

0, I, 2, 3 or 4 with the proviso that m and n are not both

O. The total number of carbon atoms in Rill and R'1l is

from 3-25. Rand R' contain I to 25 carbon atoms

when saturated aliphatic and 3 to 25 carbon atoms

when they are ethylenically unsaturated groups. Preferably,

the position ortho to the phenolic OH substituted

carbon atom is unsubstituted and also preferably the

positions ortho to the oxime carbon atom on the other

aromatic nucleus are unsubstituted. Branched chain

saturated aliphatic hydrocarbon substituents are preferred.

Compounds of the above type useful in the

present invention include the following:

2-hydroxy-3'-methyl-5-ethylbenzophenoxime

2-hydroxy-5-( I, I-dimethylpropyl )-benzophenoxime

2-hydroxy-5-( 1, I-dimethylethyl )-benzophenoxime

2-hydroxy-5-octylbenzophenoxime

2-hydroxy-5-nonyl-benzophenoxime

2-hydroxy-5-dodecyl-benzophenoxime .

2-hydroxy-2',4'-dimethyl-5-octylbenzophenoxlme

2-hydroxy-2',3',5'-trimethyl-5-octylbenzophenoxime

2-hydroxy-3,5-dinonylbenzophenoxime

2-hydroxy-4'-( l,l-dimethylethyl )-5-( 2-pentyl )-benzophenoxime

2-hydroxy-4'-( 1, I-dimethylethyl)-5-(2-butyl )-benzophenoxime

2-hydroxy-4-dodecyloxybenzophenoxime

2-hydroxy-4'-( 1, I-dimethylethyl )-5-methylbenzophenoxime

2-hydroxy-4',5-bis-( 1, I-dimethylethyl)benzophenoxime

As indicated from the above representative compounds,

various alkyl groups can be used as Rand R'.

And as set forth above, such groups may be branched 65

or straight chain. Various ethylenically unsaturated

groups can also be used as ~ and R' and th~ same may

be branched or straight cham. RepresentatIve of such

compounds are disclosed in the same patent. As disclosed

in the above patent, 2-hydroxy benzophenoximes

have the basic structure,

and are tailored with substituents to provide the required

solubility in suitable organic solvents. The extractants

include 2-hydroxy benzophenoximes in which

the substituents are alkyl radicals, ethylenically unsaturated

aliphatic radicals and alkyl or ethylenically unsaturated

aliphatic ether radicals.

The preferred 2-hydroxy benzophenoximes are those

represented by the formula:

~H" 0

CH3- -(CH,lx-S-CH,-C-OH

wherein X is 7-20,

-7'

CH,=CH-(CH,)x-S-,CH,-C-OH

wherein X is 7-20,

H,-C1\H . 0

/ ~-(CH'h-S-CH.-C -7' OH . -

H,-C

wherein X is 2-17,

3,927,169

the fully reduced and in the sulfoxide (e.g. partially

oxidized analogs), with their potential for weakly chelating

the copper ions; and finally, the enhanced acidity

of the hydrogens on the alpha carbon atom as corn-

S pared with those on simple aliphatic carboxylic acids.

This acidity again increases as one progresses from the

fully reduced (S-alkyl thioglycolic acid) through the

alkyl sulfinyl- and thence to the alkyl sulfonyl-acetic

acids. Although these substances have only meager

10 ability to extract copper from acidic aqueous solutions

of the pH ranges disclosed herein, they nevertheless are

apparently capable of rapidly forming weak copper

complexes which serve to transfer the Cu++ from the

aqueous to the organic phase, where a stronger interac-

IS tion with, and transfer to, the hydroxy phenoxime occurs

with concomitant regeneration of the transfer

accelerating agent.

The a-halo substituted carboxylic acids which may

be used as copper extraction accelerating agents for the

20 2-hydroxy benzophenoximes are represented by the

formula:

H 0

I~ ~

CH"-(CH'h-~-~-S-CH'-C_OH

R' 0

I ~

R-(CH.h-C-C-OH

- ~

wherein X is 5-17,

wherein R represents an aliphatic, aryl or an araliphatic

group, R' is a halogen atom, and X is a number from

30 7-20.

Compounds of the above type which are operative

are:

40 where X is 7-20,

where Xis 2-19,

~ 0 ~ ~

C 3 I·~ CH,-(CH,h-S-CH,-C_OH

35 !f OH

CH..-(CH.h- -C-OH

o _ ~

CH" <[I 0

CH3-1-(CH,h-i-c -7' OH

H,-\ H. If 0

'\ ~

C-(CH,h- -C-OH I . ~

H,-C

where X is 7-20,

where X is 5-20,

~ ~H 0 V CH~CJ-ceH,)~'-CH,C -P OH .l<re X , 5-20.

Operative oxidation products of the thioglycolic 50

acids are the above compounds in which the sulfur

atom has one or two oxygen atoms attached to it. In the

first stage oxidation one oxygen atom is attached to the

sulfur atom and in the second stage oxidation two

atoms of oxygen an;: attached to the sulfur atom. 55

The preferred thioglycolic acids are S-tert-octyl thioglycolic

acid and S-tert-dodecyl thioglycolic acid, referred

to herein as C3 and C4 , respectively. The preferred

oxidation products are the sulfoxides and sul- h' X' 7 20

fones of C3 and C4

. . 60 w erem IS - ,

It is believed that the activity of the S-alkyl thioglycolic

acids and their oxidation products rests upon

three features: First, the significantly higher ionization

constants (Ka ) which increase from about 1-2 X 10-4

for the former to 1-2 X 10-3 for the fully oxidized alkyl 65

sulfonyl acetic acids, as compared with Ka of about 1-2

X 10-5 for simple carboxylic acids; secondly, the contribution

of the available electrons on the sulfur atom in

3,927,169

4.9

11.0

Copper Transfer Rate

Diluent Mg Cu/m'/sec.

EXAMPLE I

0.25

0.5

1.0

Reagent C,

Addition Vol. 'it

from leaching of an ore. During the extraction phase

the mixed extractant becomes loaded with copper or

other desired metal.

It is well known that LIX 64, LIX 64N and LIX 70

5 exhibit a selectivity for copper over other metals at pH

values below about 4. The most efficient organic to

aqueous ratio can be arrived at in accordance with

procedures well known in the art. After separation of

the loaded organic phase from the aqueous phase, cop-

10 per is stripped from it with a mineral acid, such as

sulfuric, in a stripping circuit.

The liquid ion exchange process may be performed

by continuous countercurrent or batch methods.

The extraction with the extractant mixture is per15

formed at a pH in the acid range. Leach solutions of

copper ores ordinarily have a pH range from about 1.7

to 3.0.

The invention is illustrated by the following comparative

examples, and the graphs of FIGS. 1 and 2 ilIustrat20

ing the effect of the additives C3 and C4 on loading and

stripping rates, respectively, of copper with LIX 64N.

Example 4 was performed as a blank to evaluate the

C3 and C4 reagents as copper extractants.

In all of the other examples the LIX 64N content of

25 the organic phase was 10 volume percent based on the

volume of the organic solvent, and the volume ratio of

additive to LIX 64N was I to 10. The solution from

which the copper was extracted in the examples had a

pH of 2.

30 Examples I and 5 were performed using what is referred

to as a "drop" test. This test comprises introducing

the organic phase drop by drop at the bottom of a

container holding the aqueous phase. The amount of

copper transferred to the organic phase is measured as

35 milligrams of copper per square meter of organic phase

transferred per second. The stripping test of Example I

was performed in a baffled beaker with a rotating mixing

element. All other examples, extracting and stripping,

including those on which the graphs of FIGS. 1

40 and 2 are based, were performed using a pipe extractor

as disclosed in U.S. Pat. Ser. No. 175,948 filed by

Wayne C. Hazen in the U.S. Pat. Office on Aug. 30,

1971 entitled "Solvent Extraction Method and Apparatus."

In accordance with this procedure the aqueous

45 and organic phases are flowed together through the

mixing section contail,ling baffled mixing elements in a

closed pipe at a velocity to mix the phast;s in the shortest

time without the formation of too Hiany small bubbles

with the dispersion formed being transferred to a

50 settling area where the aqueous and organic phases

separate by gravity. The pipe extractor used for the

examples was 6.5 feet long x % inch in diameter and

contained 105 mixing elements.

The example which follows using the drop test proce-

SS dure wa~ performed to illustrate the increase in extraction

rate of copper by LIX 64N obtained by the addition

of various amounts of C2 to LIX 64N. The organic

solvents for the extractant were Isopar Land Amsco

175. The aqueous phase was a copper sulfate solution

60 containing 2.0 gil of copper.

where X is 7-20.

0' Br 0 I CH'-<CH'h-t-c -f' OH

~ H

O'H ~ H Br-f'0 I ~-t=~-(CH")\-~-C-OH

~ ~ -. ~

(CH

) X - CH/~,,~r- C ~~H

2V ~

where X is 7-20,

The preferred a-halo substituted carboxylic acid is

a-bromo lauric acid referred to hereinafter as C2 . A

process for the recovery of copper using this compound

alone is disclosed in U.S. Pat. 3,251,646 with times

from three minutes to one hour being reported for

significant recoveries.

A problem in the extraction of copper is that the

leach solutions of its ores contain significant amounts

of iron and the extractant used must not extract prohibitive

amounts of iron to contaminate the copper extracted.

It has been found that the extractant mixtures

of this invention are satisfactory in this respect.

The water-immiscible organic solvents in which the

extractant mixture is dissolved to form the organic

phase are the conventional ones, such as, aliphatic

hydrocarbon solvents including petroleum derived liquid

hydrocarbons, either straight chain or branched,

such as, kerosene, fuel oil, etc. Various aromatic solvents

or chlorinated aliphatic solvents may be used,

such as benzene, toluene, xylene, carbon tetrachloride,

perchloroethylene and others. The solvent must be

substantially waterimmiscible, capable of dissolving the

extraction reagent, and must not interfere with the

function of the reagent in extracting the metal values

from acid solution. A suitable solvent is one sold commercially

by Humble Oil and Refining Company under

the trademark "Isopar L". It is a fractionated isoparaffinic

hydrocarbon with a mid-boiling point of approximately

380°F. Another suitable solvent is an aliphatic

naphtha sold by Amsco Division of Union Oil Company

of California under the trade name" 175 Solvent", and

is referred to herein as "Amsco 175". Also found suitable

are hexane, and a hexanetype solvent sold by

Humble Oil and Refining Company under the trademark

"Isopar C".

The benxophenoxime component of the organic extractant

mixture should have a solubility of at least 2%

by weight in the hydrocarbon solvent in the organic 65

phase and is insoluble or immiscible with water.

The aqueous phase from which the desired metal is

extracted is ordinarily the acid leach solution resulting

3,927,169

Conditions:

25 Organics 5 volume % reagent C-3 or C-4 in kerosene

(Amsco 175), preconditioned with 3N H2S04 then

'K Cu

Stripped

.61

.35

.18

.14

Organic Assav. GIL Cu

Loaded . Stripped

-continued

EXAMPLE 4

0.5

1.0

2.0

5.0

10.0

20.0

Contact

Time

Min.

Reagent C,

Addition

Vol. 'K .

The results show that with the contact time of 0.25

minutes the amount of copper stripped in the presence

of one volume percent of the C2 additive is doubled

over that stripped without the additive in the same

time. With the same volume content of the C2additive

more copper is stripped in two minutes than was

stripped in five minutes with no additive present. The

time to reach equilibrium concentration is decreased

by a factor of at least 4 when the C2additive is present.

The following example was performed to evaluate

the reagents C3 and C4 as copper extractants.

4.0

Copper Transfer Rate

Diluent Mg Cu/m'/sec.

-continued

Amsco 175

EXAMPLE 2

1.0

2.0

5.0

Reagent C,

Addition Vol. %

~t will be ~oted from the test results that copper extractIon

rate IS doubled with the addition of 0.25 volume

percent of C2, is tripled with the addition of more than 10

?~ ,,:olume perc:ent ofC2and at 5 volume percent ofC2

It IS Increased SIX times.

The fol~owing e~ample was performed, again to illustrate

the Increase In the extraction rate effected by the

addition of the reagent C2 to LIX 64N with the ion 15

exchange process being performed in the pipe extractor

described hereinbefore. The solvent for LIX 64N

and the C2 additive in this example was hexane. The

aqueous phase was a copper sulfate solution containing

3.1 gil of copper, 1.7 gil Fe+3 and 2.9 gil Fe+2. The 20

or~anic a~d aqueous ,rhases were flowed through the

mIxer sectIon of the pIpe extractor at a velocity orO.9-1

ft.sec. at a temperature of 23°e. Two passes of the

phases through the mixer were made with the following

results.

Reagent C, Contact

Addition Pass Time G/LCu

Vol. % No. Sec. Organic Raffinate

None I 6.5 .51 2.20

2 6.5 .98 1.69

Equilibrium 20 min. 1.62 .74

l<;l; I 6.7 1.14 1.45

2 7.0 1.49 1.03

Equilibrium 20 min. 1.60 .75

Organic

Cu Loading '7<

Of Equilibrium

Results:

50 Distribution

Aque- Assay, gil Cu <;l; Cu Coefficient

Or- ous Organic Raf- Extracted KOlA

ganic pH finate

C-3 1.0 0.002 2.04 0.1 0.001

2.0 0.026 2.04 1.3 0.013

C-4 1.0 0.002 2.02 0.1 0.001

2.0 0.018 2.02 0.9 0.009

It will be observed from the above example that over

twice as·much copper was extracted in the first pass

with the C2additive present than was extracted without 40

the additive in the same period of time. In the two

passes more than one and one-half times as much copper

was extracted with the additive than without the

additive.

The following example was performed to show the 45

effect of the presence of the additive C2 on the rate of

stripping copper from LIX 64N. The solvent used for

LIX 64N and the additive was Arnsco 175. The stripping

solution was a 3N H2S04solution containing 20 gil

of copper as copper sulfate. The propeller in the baffled

beaker in which the process was performed was

rotated at 900 RPM. An organic to aqueous ratio of 3: I

was used. The experiment was performed at a temperature

of 30°C with samplings being taken at various

intervals.

20 gil Na2S04

Aqueous Synthetic sulfate solution containing 2.06

gil Cu, and 2 gil Na2S04

Contact 01A ratio 1/1

Contact time 5 minutes at pH

Aqueous pH Adjusted with IN NaOH

Temperature 23°C

EXAMPLE 3

Reagent C,

Addition

Vol. "k

None

1.0

Contact

Time

Min.

0.25

0.5

1.0

2.0

5.0

10.0

20.0

0.25

Organic Assay, GIL Cu

Loaded Stripped

2.22

1.50

1.45

1.32

1.00

.44

.17

.15

2.58

.84

<;l; Cu

Stripped

The results show that the C3 and C4 reagents do not

appreciably extract copper under the conditions set

60 forth.

The following example was performed to illustrate

the effect of the reagents C3 and C4 on the copper

extraction rate of LIX 64N, the experiment being performed

by the drop test described hereinabove. The

65 solvent for the LIX 64N and the C3 and C4 additives

was Arnsco 175. The aqueous phase, i.e., the copper

sulfate solution, contained 1.9 gil copper, 2 gil Fe+3

and 2 gil sodium sulfate.

EXAMPLE 5

3,927,169

EXAMPLE 7

Reagent Addition Copper Transfer Rate Contact Assa\'. GIL

Mg Cu/M'/Sec. 5 Reagent Pass Time Org,mic . Raffinate

Addition No. Sec. Cu Fe Cu

None 4

0.5 Vol. 'Il c;-,a 20 None I 6.5 .57 .003 2.38

1.0 30 2 .88 .005 1.88

2.0 41 3 1.16 .006 1.59

0.5 C, 13 I'll C" I 5.9 1.22 .004 1.19

1.0 15 2 6.5 1.49 .007 .89

2.0 12 10 3 5.9 1.60 .009 .81

I'll C, I 5.9 1.07 .003 1.42

2 6.5 1.43 .006 .98

3 5.9 1.59 .008 .85

Organic

Cu Loading 'Il

Of Equilibrium

The results show that, in the same times, as compared

to copper extraction with no additive present, extraction

rates were increased by factors of 5, 7.5, and 10 15

with, respectively, 0.5, I, and 2 volume percent of C3

present. Likewise, extraction rates were increased by

factors of 3, 3.8, and 3, respectively, with the use of

0.5, I and 2 volume percent of C4 additive.

The following example was performed, again, to iIIus- 20

trate the effect on copper extraction rate of the presence

of the reagent C3. The solvent for LIX 64N and

the reagent was Amsco 175. The aqueous phase comprised

a copper sulfate solution containing 3.1 gil of

copper, 1.7 gil Fe+3 and 2.9 gil Fe+2 . A pipe extractor 25

was used. A flow velocity of 0.9 ft/sec of the liquids was

used. An organic to aqueous ratio of 1.5: I and a temperature

of 23°C were used.

EXAMPLE 6

Reagent C" Contact

Addition Pass Time Assa\,. GIL Cu

Vol. 'Il No. Sec. Organic - Raffinate

None I 6.9 .55 2.20

2 6.8 .85 1.67

Equilibrium 20 Min. 1.54 .73

I'll I 7.0 1.24 1.15

2 6.8 1.39 .85

Equilibrium 20 Min. 1.50 .76

The example shows that with essentially the same

contact time, the amount of copper extracted using 1

volume percent ofCa was almost doubled in two passes

over that extracted with no additive present.

The example shows that using essentially the same

contact time, the amount of copper extracted was increased

by a factor of 1.7 by the addition of I volume

percent of reagent C3 . Likewise, copper extraction

increased by a factor of 1.6 in the same time by the

addition of I volume percent ofC4 additive. The example

also illustrates that the presence of either of the

reagents C3 or C4 does not increase iron extraction to

any appreciable extent.

The following example was performed to illustrate

the effect ofCa and C4 additives on the rate of stripping

copper from LIX 64N. The organic solvent used was

Isopar C. The strip solution was a 3N sulfuric acid

solution containing 20 gil copper as copper sulfate. A

pipe extractor was used. The velocity of liquids through

the mixing section of the pipe extractor was I ft/sec. An

organic to aqueous ratio of 1: 1 and a temperature of

23°C were used.

EXAMPLE 8

Organ ic Assay. GIL Cu

Reagent Pass Loaded Stripped 'Il Stripped Stripping Rate

Addition No. Cu Fe Cu Fe Cu Fe GIL Cu/Sec.

None 0 1.16 .006

I .63 .003 46 50 .082

2 .35 .0008 70 87 .043

3 .18 .0008 84 87 .026

1% C" 0 1.60 .009

I .37 .003 77 67 .19

2 .087 .0006 95 93 .044

3 .058 .0004 96 96 .004

I'll C, 0 1.59 .008

1 .62 .003 61 63 .15

2 .23 .0009 86 89 .060

3 .11 .0005 93 94 .018

The following example using the pipe extractor was

performed to show the effect of the presence of the

reagents C3 and C4 on the copper loading rate of LIX

64N. The organic solvent for the LIX 64N and additives

Ca or C4 was Isopar C. The aqueous phase comprised

copper sulfate solution containing 3.1 gil of

copper, 1.7 gil of Fe+a and 2.9 gil Fe+2 . A flow velocity

of 0.9 ft/sec was used. Three passes were used.

The example shows that in the same contact time,

during the first pass with one volume percent of C3

present, the copper stripping rate was increased by a

factor 2.3, and with one volume percent of C4 present,

stripping rates were increased by a factor of 1.8. Com-

65 parable results were obtained in the second and third

passes.

The final example was performed using as additives

the oxidation products ofC4 , one of the products being

3,927,169

H 0 I ~

R-S-C-C-OH

wherein R is an aliphatic, aryl, or an araliphatic group,

and tfte oxidation product of the thioglycolic acids has

the formula:

The graph of FIG. 2 shows graphically the accelerated

stripping rate achieved by the addition of Ca and

C4 additives to LIX 64N. A pipe extractor was used.

One percent of the additive based on the amount of

5 solvent was used. The organic solvent was Isopar C. A

flow velocity of I ft/sec was used. The tests were performed

at 22°C. The strip solution was a 3N sulfuric

acid solution containing 20 gil of copper as Cu S04'

It will be noted from the graph of FIG. 2 that the

10 stripping rate was accelerated by factors of 2 and 1.6 by

the presence of C3 and C4 additives, respectively.

The volume percent of the C2 • C3 and C4 type additives

based on the amount of LIX 64N reagent (2hydroxy

benzopnenoxime) can vary from 0.1 to 100

15 percent, with a preferred volume percent of additive to

reagent being about 1 to about 20, The contact time of

the mixed extractants (2-hydroxy benzophenoximes

like LIX 64N plus additive) with the aqueous phase for

20 extraction, irrespective of the type mixing equipment

used, can vary from a few seconds up to about one

minute with satisfactory results being obtained. This is

in contrast to a contact time of at least two minutes

required for satisfactory copper extraction with the

25 LIX compounds alone in commercial operations. The

contact time of the stripping agent with the mixed extractant

loaded with copper is from a few seconds up to

about one minute for satisfactory stripping. Again, this

is in contrast to a time of about two minutes contact

30 time for satisfactory stripping of copper from the LIX

reagents without the additives.

The chief advantages of the process are that the addition

of the copper extraction and stripping acceleration

additives increases the copper extraction rate of the

35 LIX reagents up to a factor of at least 3 and the rate at

which copper can be stripped from them by a factor of

up to at least 2. The result is a decided economic improvement

in that much less capital equipment is required,

and the amount of expensive agent which is tied

40 up and the time it is tied up are drastically reduced

from a comparative economic standpoint.

What is claimed is:

1. A process for recovering copper values from an

aqueous medium comprising contacting the aqueous

45 medium with a water-immiscible organic solvent having

dissolved therein an extractant comprising:

a 2-hydroxy benzophenoxime having a solubility of at

least 2% by weight in the organic solvent and as a

copper extraction accelerating agent for the 2hydroxy

benzophenoxime a compound selected

from the group consisting of thioglycolic acids and

oxidation products of thioglycolic acids.

2. The process of claim 1 in which

the thioglycolic acid has the formula:

EXAMPLE 9

o 0

CI2H,,-SII-CH2COOH and CI2H25-"0-CH2COOH

Test Control No.1 No.2

Additive (1% C.l (Sulfoxide) (Sulfone)

Contact Time, Sec. 6.9 6.7 6.5

Drop Size, cm3/Drop .041 .029 .026

Surf.Area, cm2/ Drop .58 .46 .42

Temp.,oC 23 25 23

Organic Assay

G/LCu .14 .22 .22

Transfer Rate

Mg Cu/m2/sec. 14.4 20.8 21.0

The results show that the sulfoxide and sulfone are

even better copper extraction accelerators for LIX 64N

than C4. In substantially the same time 45 percent more

copper was exextracted with LIX 64N containing these

additives than was extracted by LIX 64N containing

the C4 additive alone.

Reference is now made to the graph of FIG. 1 depicting

comparative results of experiments performed in

extracting copper with LIX 64N with the addition of

the C3 and C4 reagents and without the addition of any 50

reagents. One volume percent of the reagents C3 and C4

based on the organic solvent was used. This amounts to

a volume ratio of 1:10 of additive to LIX 64N. The

organic solvent was Isopar C. A pipe extractor was

used. The aqueous phase was a copper sulfate solution

containing 3 gil copper, 2 gil Fe+3 and 3 gil Fe+2. The

solution had a pH of 2.0 at the start. A flow velocity of

1 ft/sec was used. An organic to aqueous ratio of 1.5/1

and a temperature of 21 ° - 23° were used. Three passes

were made. Essentially the same contact time for all 60

passes was used.

The graph of FIG. 1 shows that copper extraction

rate with 1 volume percent of C3 present increased by

a factor of about 3 on the first pass, 1,6 on the second

pass and 1.3 on the third pass. Likewise, with one vol- 65

ume percent of C4 present, the rate of copper extraction

increased by a factor of about 2.3 on the first pass,

1.5 on the second pass, and 1.3 on the third pass.

a partial oxidation product and the other a complete

oxidation product. The oxidation products were made

in the conventional manner by oxidation with hydrogen

peroxide in the presence of glacial acetic acid, one-half

the stoichiometric amount of hydrogen peroxide for

complete oxidation being used for the partial oxidation

and the complete stoichiometric amount being used for

complete oxidation. The sulfoxide was produced by

partial oxidation and the sulfone by complete oxidation,

and these additives are so identified in the following

table of results. They are represented by the following

chemical formulas:

Using the drop test procedure described above in

separate tests of the sulfoxide and sulfone, 10 volume

percent LIX 64N and one volume percent additive

were mixed in Arnsco 175 as the solvent and contacted

with an aqueous solution containing 2.0 gil Cu, 3 gil

Fe+2, 2 gil Fe+3 , and 2 gil Na2S04 with the following

results which include comparative results obtained on a

control using one volume percent C4 additive.

3,927,169

11. The process of claim 7 in which at least one R

group of the 2-hydroxy benzophcnoxime is in the 5

position.

12. The process of claim 1 in which the thioglycolic

acid is a member selected from the group consisting of

octyl thioglycolic acid and its oxidation products.

13. The process of claim 1 in which the thioglycolic

acid is a member selected from the group consisting of

dodecyl thioglycolic acid and its oxidation products.

14. In the process for recovering copper values from

an aqueous medium which comprises contacting the

aqueous medium with an extractant comprising a 2hydroxy

benzophenoxime followed by stripping the

copper from the loaded extractant to recover the copper,

the improvement which comprises stripping the

copper from the extractant in the presence of a copper

stripping accelerating agent for the 2-hydroxy benzophenoxime

comprising a member selected from the

group consisting of a thioglycolic acid or an oxidation

20 product of a thioglycolic acid.

15. The process improvement of claim 14 in which

the stripping is performed in a time of up to about one

minute.

16. A process for recovering copper values from an

25 aqueous medium comprising contacting the aqueous

medium with a water-immiscible organic solvent having

dissolved therein an extractant comprising:

a 2-hydroxy benzophenoxime having a solubility of at

least 2% by weight in the organic solvent and as a

copper extraction accelerating agent for the 2hydroxy

benzophenoxime an organic compound

containing the group

OH NOH

/o-~-< Z R R'

In n

wherein R is an aliphatic, aryl or araliphatic group, R1

is oxygen and R2 is oxygen or an electron pair.

3. The process of claim 2 wherein the aliphatic group

in all structural formulas has from 7-20 carbon atoms.

4. The process of claim 1 in which the aqueous me- 5

dium is contacted with the extractant for a time up to

about one minute.

5. The process of claim 1 in which the accelerating

agent is present in an amount from about 0.1-100 vol- 10

ume percent of the 2-hydroxy benzophenoxime.

6. The process of claim 1 in which the 2-hydroxy

benzophenoxime is a member selected from the group

consisting of alkyl substituted, ethylenically unsaturated

aliphatic substituted and alkyl or ethylenically 15

unsaturated aliphatic ether substituted 2-hydroxy benzophenoximes.

7. The process of claim 6 in which the 2-hydroxy

benzophenoxime has the formula:

50 * * * * *

in which a sulfur atom is separated from a carboxyl

group only by one lower alkyl group.

17. A process for recovering copper values from an

40 aqueous medium comprising contacting the aqueous

medium with a water-immiscible organic solvent having

dissolved therein an extractant comprising:

a substituted hydroxy benzophenoxime having a solubility

of at least 2% by weight in the organic solvent

and as a copper extraction accelerating agent for

the substituted hydroxy benzophenoxime a compound

selected from the group consisting of thioglycolic

acids and oxidation products of thioglycolic

acids. .

in which Rand R' may be individually alike or different

and are saturated aliphatic groups of 1-25 carbon 35

atoms, ethylenically unsaturated aliphatic groups of

3-25 carbon atoms or -OR" where R" is a saturated

or ethylenically unsaturated aliphatic group as defined,

m and n are.O, I, 2, 3 or 4 with the proviso that both are

not 0 and the total number of carbon atoms in Rill and

R'1l is from 3-25.

8. The process of claim 7 in which R of the 2-hydroxy

benxophenoxime is an ethylenically unsaturated group.

9. The process of claim 7 in which R' of the 2- 45

hydroxy benzophenoxime is an unsubstituted branched

chain aliphatic hydrocarbon group.

10. The process of claim 7 in which R of the 2hydroxy

benzophenoxime is an unsubstituted branched

chain hydrocarbon group.