United States Patent [19]
Hadzeriga
[ 11 ] 3,853,981
[45] Dec. 10, 1974
10 Claims, 1 Drawing Figure
Primary Examiner-Herbert T. Carter
Attorney, Agent, or Firm-Sheridan, Ross & Fields
An ion exchange process for selectively recovering a
first metal in solution from a second metal without
build-up of the second metal in the circuit. The process
comprises first separating from the ion exchange
recovery circuit for the first metal a bleed stream of
the aqueous which is recycled to the leaching stage to
maintain a required concentration of first metal in the
leaching stage. The remaining aqueous is further contacted
countercurrently with barren organic to completely
remove all of the first metal from it. The aqueous
is then sent to a recovery circuit for the second
metal. After the second metal recovery the raffinate
from this stage is returned to the leaching stage. The
result is that the second metal is removed from the
system at substantially the same rate at which it is introduced
into the leaching stage in the continuous
process.
[54] LIQUID ION EXCHANGE PROCESS FOR
THE RECOVERY OF METALS
[75] Inventor: Pablo Hadzeriga, Arvada, Colo.
[73] Assignee: Cyprus Mines Corporation, Los
Angeles, Calif.
[22] Filed: June 26, 1972
[21] Appl. No.: 266,456
[52] U.S. Cl. 423/24, 423/32, 423/100,
423/109,423/105,75/103,75/101 BE,
75/117,75/120,204/106,204/114
[51] Int. CI... ..... COlg 3/00, COlg 3/10, COlg 3/14,
COlg 9/00, C22b 15/10, C22b 19/24, C22b 19/26
[58] Field of Search 423/24, 32, 33,109,100,
423/105; 75/100 BE, 101 R, 103, 117
[56] References Cited
UNITED STATES PATENTS
2,805,918 9/1957 Van Hare et al. 423/105
2,839,388 6/1958 Van Hare et al. 423/105 X
[57] ABSTRACT
I AMMONIUM I I FEED ~ CARBONATE IAIR OR OXYGEN I
SOURCE (SCRAP BRASS) SOURCE
~ I LEACHING 1
!
FEED
SOLUTION
1 PREGNANT ORGANIC I H2SO I 4 1-- STRIP
STAGE I
ION EXCHANGE
BLEED AQUEOUS
STRIP
RECYCLE ORGANIC BARREN LIQUOR
ORGANIC
STAGE 2
ION EXCHANGE I COPPER }- ELECTROLYSIS
AQUEOUS ORGANIC
STAGE 3
ION EXCHANGE
AQUEOUS
ZINC RECOVERY
DEHPA EXTRACTION
OR PRECIPITATE WITH
C02 OR BY BOILING
OFF NH3
RAFFINATE
RECYCLE
SPENT ELECTROLYTE
RECYCLE
AMMONIUM
CARBONATE
SOURCE
BLEED
RECYCLE
FEED
(SCRAP BRASS)
~
LEACHING
T
FEED
SOLUTION
t
STAGE 1
ION EXCHANGE
AQUEOUS
STAGE 2
ION EXCHANG E
AQUEOUS
STAGE 3
ION EXCHANGE
AIR OR OXYGEN
SOURCE
I
PREGNANT ORGANIC
I~RGANIC IBARREN
ORGANIC
ORGANIC
l
H2S04
STRI P
STRIP
LIQUOR
. COPPER
ELECTROLYSIS
Ir
SPENT ELECTROLYTE
RECYCLE
u
:r>
.-..l,
:z:
.-..l,
C'"
CJ
r1
~
o
C-.E. ~
w
RAFFINATE
RECYCLE
AQUEOUS
ZINC RECOVERY
DEHPA EXTRACTION
OR PRECIPITATE' WITH
C02 OR BY BOI LIN G
OFF NH3
co
U1
W
wc.o'
ro
t-J
3,853,981
2
The operation of the invention is described with reference
to the accompanying drawing of the flow sheet.
solution is prevented and commercial grade copper and
zinc are recovered in quantitative amounts.
Copper is extracted with a copper selective ion exchange'
agent from· an ammoniacal leach solution of
5 scrap brass containing copper and zinc values. A prescribed
portion of aqueous from the copper extraction
step is recycled to the leach solution to maintain
enough cupric copper therein to expedite leaching.
Zinc build-up in the leach solutionis prevented by
sending the remaining aqueous to a zinc recovery circuit
where zinc is removed and the raffinate from this
stage recycled to the leaching stage. To insure maximum
copper recovery and that the recovered zinc is of
commercial grade and not contaminated with copper,
the remaining aqueous referred to above is contacted
in at least one countercurrent extraction stage with bare
ren organic for complete removal of copper before
reaching the zinc recovery circuit.
. BACKGROUND OF THE INVENTION
1
LIQUID ION EXCHANGE PROCESS FOR THE
RECOVERY OF METALS
The increasing world-wide scarcity of copper with
consequent increase in price has stimulated a demand
for an economical process for recovering copper from
scrap brass and other copper alloys. The present invention
is related to a process for recovering copper from 10
ammoniacal solutions used to leach scrap copper al~
loys, particularly, brass and bronze.
The art for leaching copper from its ores and alloys
with ammoniacal solutions is well developed. For example,
it is known that a leach solution of 30 gil NH3 15
and 30 gil of (NH4h C03 will dissolve 40 gil of copper.
It is also well known that a certain amount of cupric
copper must be present in the solution to maximize the
rate at which copper is dissolved. Otherwise, without 20 DETAILED DESCRIPTION OF THE INVENTION
adequate oxidation, the metallic copper will reduce any
cupric ion present in solution in accordance with the
reaction: CUD+Cu++ +-:-"2 Cu+ and leaching will cease.
Therefore, during leaching. air or oxygen is bubbled
h h h I hi' ·d· h . The drawing isa schematic showing of the ion ext
ro~g t e eac so utlon to OXI Ize t e cuprous Ion to 25 change system in which an illustrative embodiment or
cupnc.
While ammoniacal leaching provides an effective application of the process is presented. This system was
means for solubilizing copper and zinc from scrap used in obtaining the results presented further on in the
brass, it is difficult to recover the copper from the leach specification. In the drawing a conventional liquid ion
solution in the presence of dissolved zinc. exchange circuit for the recovery of copper from an
Most of the ion exchange extractants for copper are 30 ammoniacal leach solution is represented followed by
not sufficiently selective for copper to permit their use a conventional sulfuric acid stripping circuit followed
for effectively separating this metal in solution in the by an electrolysis step forelectrowinning copper. A
bleed recycle of a portion of the aqueous from the first
presence of other metals. However, the General Mills copper recovery stage to the leaching stage is shown
Company of Minneapolis, Minn. has introduced on the 35 with another portion of the aqueous going through two
market some copper ion exchange agents sold under a~ditional copper recovery stages before proceeding to
the names of LIX-63, LIX-64, LIX-64N, LIX-65N a zinc recovery circuit:The direCtion of the arrows inand
LIX-70 which are highly selective to copper. One dicates the countercurrent travel of aqueous and orof
the active agehts of some of t~ese extractants, LIX- ganic phases..
-64 an~ LIX-6~N, for ~xample, IS a 2-hydroxy benzo- 40 In the description which follows the combination of
phenoxlme as dlsclosed.In U.S. Pat. No: 3,42~,449. AI- the first ion exchange stage, the H2S04 strip and the
th?ugh ~he problem whIch ~he present InventIon solves copper electrolysis will be referred to as the copper reanses
WIth the use of selectIve extra.ctants~ the extra~t- covery circuit, while ion exchange stages 2 and 3 with
ants .themselves fo:m ~o Par.t of the InventIOn as .the In- the zinc recovery· stage will be referred to as the zinc
ventlOn fl.nds apphcatlon WIth the use of selectIve ex- 45 recovery circuit. The recycle of the aqueous bleed from
tractants.In g~neral. . stage 1 is referred to as the bleed recycle and the recy-
The chIef dlsadvanta~e of the use of selectIve sol~ent c1e of the raffinate from the zinc recovery stage is reextra~
t~nts ~or separat~ng cop~er ~alues from solutl?ns ferred to as the raffinate recycle, the main stream of the
con.tammg zmc value~ IS that .zmc If not .removed bUIlds 0 aqueous proceeding through stages 1, 2 and 3.
up m th~ lea~h solut~~n durIng a contmu~us proc~s~. 5 The leach solution comprises copper and the zinc
Upon dlssolvmg addItIOnal copper, the zmc preclpl- values dissolved in an ammoniacal solution containing
tates as a basic carbonate and coats the surface of un- about equal amounts of ammonia or ammonium hydissolved
scrap, thus retarding further copper solution. droxide and ammonium carbonate. An ammonium car-
Various expedients to combat this, such as agitation bonate source is available to adjust the composition of
leach, have been resorted to by the prior art. 55 the leaching solution. Each of the stages 1, 2 and 3 in-
Accordingly, it is a principal object of the invention c1udes a conventional mixer-settler system to perform
to provide an ion exchange process,for the selective re- the separation.
covery of a first metal in solution with a second metal The organic solvent was prepared using the abovein
which build-up of the second metal in the leach solu- 60 mentioned extractants dissolved in an inert diluent,
tion is prevented. such as Napoleum 470, a hydrocarbon distillation frac-
Another object of the invention is to provide an ion tion. Other conventional organic diluents may be used.
exchange process as stated for the principal object in The concentration of extractant in the solvent will dewhich
both metals are recovered in commercial grade pend on the desired characteristic of the circuit.
purity. 65 Air or oxygen is introduced in the leaching step to ox-
A further object of the invention is the provision of idize copper to the cupric form to increase leaching
an ion exchange process for the recovery of copper in rate. The feed solution goes to stage 1 where more than
solution with zinc in which build-up of zinc in the feed 50% of the copper is extracted into the organic phase.
3
3,853,981
4
GIL
GIL
34 - 35
9.5 - 9.7
40 - 55
21.4 - 21.6
Cu
Zn
NH. co.
COMPONENT
COMPONENT
The aqueous feed for the results of Table 2 had a pH
of 10.4 and the following composition:
Cu(NHa).++ + 2(OH)- + 2RH + 2H20+---+ R2Cu + 4
NH.OH
The pregnant organic moving countercurrently to the so that for this reaction the-ammoniaieach sOlution is
aqueous phase goes to the sulfuric acid stripping circuit completely regenerated. However, some losses of amwhere
the copper is stripped and copper sulfate liquor monia and CO2 do occur during the operation of the
goes to electrolysis where metallic copper is recovered process. Losses of both gases are kept at a minimum by
at the cathode with the reformation of sulfuric acid 5 recycling the aqueous from the copper recovery circuit
which is recycled back to the stripping stage. The bar- and the raffinate from the zinc recovery circuit.
ren organic from the H2S04 stripping stage is diverted The process of the invention was performed in accorto
extraction stages land 3. dance with the flow sheet of the drawing. The results
A.portion of aqueous from stage I is recycled to the in terms of material balances set forth in Tables I and
leaching stage as a bleed for further dissolution of cop- 10· 2 below are representative of those obtained in prac- .
per. It is important to recycle a substantial amount of tice.
cupric copper to the leach solution as its presence max- The aqueous feed used for the results presented in
imizes the rate of leaching of copper from the brass Table I had a pH between 11.4 and 12 and the followscrap
as explained earlier. The amount of copper which 15 ing composition: _. __.... _..
must be recycled for a continuous process can be calculated
and a prescribed portion of the aqueous diverted
accordingly.
The remainderof the aqueous travels from stage 1 to
stages 2·and 3 where it is countercurrently contacted 20
with barren organic to provide an effective recovery of ---------------------
any copper remaining in this portion.
From stage 3 the substantially copper-free portion of
aqueous goes to the zinc recovery circuit where zinc is
recovered by conventional solvent extraction with di 25
2-ethyl hexyl phosphoric acid [DEHPA] or by precipitation
by addition of carbon dioxide or by boiling off
ammonia, procedures well known inthe art. Commer- ~~ 29.6
cial grade substantially copper-free basic zinc carbon- NHa
2~:~5
ate, zinc oxide or the metal is finally recovered by con- 30 co, 30.7
ventionalprocedures.---··....-----..--.------.-..--...---.
The raffinate from the zinc removal stage is recycled The organic phase for copper recovery consisted of
and mixed with the bleed stream of aqueous from the 10% LIX-64N, 5% isodecanol and 85% Napoleum 470
first stage for return to the leaching stage. The amount (volume percentages). The loaded organic was
of aqueous going to the zinc recovery circuit should be 35 stripped with a 200 gil H2S04 solution. The process was
sufficient for removal of a quantity of zinc equal to that operated at room temperature. The copper strip liquor
dissolved in the leaching stage. Contacting countercur- was fed to a small electrolytic cell whereby copper was
rendy the portion of aqueous from stage I going to the plated and the depleted electrolyte was recycled to the
zinc recov.ery circuit with barren organic in stages 2 stripping circuit.
and 3 before zinc recovery insures removal of substan- 40 In the . . . . d f: ZInC reco~ery cIrcuIt zmc was extracte rom
tially all of the copper with the result that the zinc re- the aqueous by usmg DEHPA. (10% DEHPA, 5% Isocovered
meets commercial grade specifications. The decanol, 85% Napoleum ~70 10 v?lume percentages).
barren organic is more effective for removal of the re- T,he loaded solvent was stnpped WIth 30 gil H2S04 and
maining copper in the aqueous than partially loaded or- 45 zmc recovered from the ZInC sulfate formed by stanganic
dard procedures.
Am'monia and carbon dioxide losses are a consider- !he test from which the ~esults of Table 1 were ob-
. .. tamed was operated contmuously for twenty hours
atlon for a commercIally feasIble process and they must h'I' th t t ~ th It f T bl 2 th
be held to a minimum. The reaction involved in the ex- w I e In e es or ~ resu s 0 a e e process
t f . ti th f' was also operated contmuously for twenty-seven hours.
rac Ion process or e recovery 0 copper IS: 50 At the end of each test complete analyses were performed
across the unit and material balances for the
last hour of operation were obtained. These material
balances are presented in Tables 1 and 2.
TABLE 1
COPPER
In: Cu 34.5 gIl 500 mllhr = 17.25 g
Out: Bleed recycle IS.5 gil 400 ml/hr = 6.20g
Strip 41.0 gil 240 mllhr = 984 1
17.04 11 VB. 17.25 g in feed
98.8% accounted for
ZINC
In: Zn 9.67 gIl 500 ml/hr~ 4.84 g
Out: Bleed recycle 9.20 gil 400 ml/hr = 3.68 g
Strip Zn 4.19 gil 100 ml/hr = 0.42 g
Strip Cu 0.11 gIl 240 mllhr = 0.03 g
Rafftnate 0.01 gIl 100 ml/hr =
4.13 g '5. 4.84 g in feed
85.3% accounted for
5
3,853,981
6
TABLE 2
In: Cu
Out: Bleed recycle
Strip
29.6 gIl
16.4 gil
32.8 gIl
COPPER
500 ml/lIr = 14.80 g
400 ml/hr = 6.56 g
240ml!hr=~
14.43 g vs. 14.80g in feed
97.5% accounted for
In: Zn
Out: Bleed recycle
Strip Zn
Strip Cu
Raffinate
9.15 g/I
9.15 gil
4.19 gil
0.91 gil
5.64 gIl
ZINC
500 ml/hr = 4.58 g
400 mllhr = 3.66 g
50 ml/hr = 0.21 g
240 mllhr = 0.22 g
100 ml/hr = 0.56 g
4.65 g vs. 4.58g in feed
101.5% accounted for
25
35
45
f. stripping copper from said ion exchange agent with
a stripping agent for copper,
g., recov~rin,g copper from the stripping agent, and,
h. recycling the barren ion exchange agent from step
(f) to step (a) after contacting it with said remainderof
a9.11eous pl1ase.
9. A continuous countercurrent ion exchange process
for the selective recovery of copper and zinc from
an ammoniacal ammonium carbonate leach solution in
. which process the cupric-cuprous ratioof the leach solution
is maintained at an active leaching level and the
30 copper is recovered in the presence of zinc without
build-up of zinc in the leach solution, the process comprising
the following operations performed continuously
and simultaneously with the aqueous and organic
phases passing countercurrent to each other:
a. continuously adding copper and zinc containing
feed to the leach solution in a leaching stage to provide
an aqueous phase containing copper and zinc
ions,
b. flowing said aqueous phase to a first copper recovery
stage and recovering copper from said aqueous
phase by ion exchange by contacting said aqueous
phase countercurrently with a water immiscible organic
phase comprising a copper selective ion exchange
agent in an organic diluent,
c. recycling a bleed portion of said aqueous phase
from the first copper recovery stage of step (b) to
the leaching stage to maintain the cupric-cuprous
ratio of said leach solution at an active leaching
level,
d. passing the pregnant organic phase to a copper
stripping stage to strip copper from the organic
phase leaving the organic phase substantially barren,
e. recycling the barren organic phase to said first copper
recovery stage where it is again loaded with
copper,
f. passing the remainder of said aqueous phase to a
zinc recovery stage to recover zinc therefrom at a
rate substantially equal to the rate of addition of
zinc to the leach solution to prevent build-up of
zinc in the leach solution, and
g. recycling spent raffinate from said zinc recovery
stage to said leaching stage,
whereby as zinc and copper are continuously
added to said leach solution the cupric-cuprous
ratio in said leaching solution is continuously
maintained at an active leaching level and zinc is
continuously removed from said leach s,:!lution at
The results show that build-up of zinc in the leach solution
can be effectively controlled by use of the flow
sheet. The plated copper from the copper strip liquor 20
meets the commercial specifications for this metal. The
strip zinc solution was pure enough to warrant the recovery
of a basic zinc carbonate, zinc oxide or zinc
metal meeting commercial specifications.
What is claimed is:
1. A continuous ion exchange process for the selective
recovery of copper and zinc from an ammoniacal
ammonium carbonate leach solution in which zinc and
copper are continuously added to the leach solution
and recovered without build-up of zinc in the leach solution,
the process comprising:
a. contacting the leach solution in an ion exchange
circuit for copper with a water immiscible organic
phase comprising a copper selective ion exchange
agent in an organic diluent,
b. recycling a bleed portion of the aqueous phase
containing copper and zinc from the ion exchange
circuit to the leach solution to maintain the cupriccuprous
ratio therein at an active leaching level,
c. recovering zinc from the remainder of the aqueous 40
phase at a rate substantially equal to the rate of addition
of zinc to the leach solution to prevent buildup
of zinc in the leach solution,
d. recycling the raffinate from step (c) to the leach
solution, and
e. recovering copper from said organic phase.
2. The process of claim 1 in which said ion exchange
extractant is a benzophenoxime.
3. The process of claim 1 in which said zinc is recovered
from said remainder of the aqueous phase by .sol- 50
vent extraction with di 2-ethyl hexyl phosphoric acid.
4. The process of claim 1 in which zinc is recovered
from said remainder of the aqueous phase by boiling off
ammonia.
5. The process of claim 1 in which zinc is recovered 55
from said remainder of the aqueous phase by adding
carbon dioxide.
6. The process of claim 1 in which substantially all of
the remainder of copper is removed from said remainder
of aqueous phase before removal of zinc therefrom 60
and recycle of the barren raffinate to the leach solution.
7. The process of claim 6 in which the remainder of
copper is removed by contacting said remainder of
aqueous phase with barren organic phase resulting 65
from stripping copper from said ion exchange agent.
8. The process of claim 7 to which is added the following
steps:
3,853,981
7
a rate substantially equal to its rate of introduction
to prevent zinc build-up in the leach solution.
to. The process of claim 9 including at least one additional
copper recovery stage immediately following
said first copper recovery stage and the continuous
8
countercurrent circulation of said remainder of aqueous
phase and said barren organic phase therethrough
before the organic phase is returned to said first copper
5 recovery stage.
* * * * *
10
15
20
25
30
35
40
4S
50
55
60
65