United States Patent [19]
Shaw
[11]
[45]
4,268,380
May 19, 1981
7 Claims, 2 Drawing Figures
An improvement in the froth flotation separation of
metallic sulfide mineral ores, particularly those ores
bearing copper and molybdenum, in which a mercaptan
collector is used in an earlier primary flotation stage, the
improvement comprising the addition of activated carbon
to achieve deactivation of the mercaptan collector
prior to the component mineral separation stage,
thereby providing enhanced separation of the minerals.
2,957,576 10/1960 Henderson 209/167
3,137,649 6/1964 De Benedictis 209/167 X
3,919,079 1111975 Weston 209/166
4,211,644 7/1980 Wiechers 209/166
FOREIGN PATENT DOCUMENTS
1011183 4/1952 France 209/167
358460 4/1930 United Kingdom 209/167
OTHER PUBLICATIONS
Froth Flot, 50 Anniv. vol., Aimrne, 1962, pp. 394, 395.
Primary Examiner-Robert Halper
Attorney, Agent, or Firm-Keil & Witherspoon
[54] FROTH FLOTATION PROCESS
[75] Inventor: Douglas R. Shaw, Tucson, Ariz.
[73] Assignee: Pennwalt Corporation, Philadelphia,
Pa.
[21] Appl. No.: 62,092
[22] Filed: Jul. 30, 1979
Related U.S. Application Data
[63] Continuation-in-part of Ser. No. 934,132, Aug. 15,
1978, abandoned.
[51) Int. C1,3 B03D 1/06
[52] U.S. Cl 209/167
[58] Field of Search 209/166, 167
[56] References Cited
U.S. PATENT DOCUMENTS
1,261,810 4/1918 Hebbard 209/167
1,839,155 1211931 Lubs 209/166
1,904,460 4/1933 Moses 209/166
2,385,527 9/1945 Mensfee 209/166
2,559,104 7/1951 Arbiter 209/167 X
2,811,255 10/1957 Nokes : 209/167
2,834,430 5/1958 Johnson 209/166
[57] ABSTRACT
GENERAL FLOWSHEET AND RESULTS ORE A
STANDARD PLANT CONDITIONS
. lNO DDMl
TAILING
RECOVERY,%
Cu -90.0
Mo-75.4
Cu- Mo CLEANER
CONCENTRATE
A.TJ9~ ,J;Qtl.Q!I!Qr-§. ! _~!IY.~~Q...~~El..ON
1 1 CuoMo CuoMo
SEPARATION SEPARATION
STANDARD PLANT
'§~A.R
CuOMo
SEPARATION
OF
Cu IN SEPn. FEED
OF
Cu IN SEpn FEED
OF
Cu IN SEpn FEED
Cu Cone
81.3%
Mo CIRCUIT
18.7%
Cu Cone.
66.6% 33.4%
Cu Cone
91.8%
Mo CIRCUIT
8.2%
GENERAL FLOWSHEET AND RESULTS ORE A
~
~
sa
-'
0"0
-~
s::
~
c.
.Vl
0/0
IROUGHER I iSCAVENGER ~"'''IAILII'''''
I
RECOVERY,
Cu- 91.5
Ro- Scav Cone Mo-76.6
REGRIND a
CLEANING
~%
WITH DDM0.0075
Ib/TON ORE
TO SC1VENGER
STANDARD PLANT CONDITIONS
(NO DDM)
IROUGHER
I
:SCAVENGER II·ULINIJ I
RECOVER
Ro-SeQv. Cone
Cu -90.0
Mo -75.4
REGRIND a
CLEANING
1 !
Cu-Mo Cu-Mo
SEPARATION SEPARATION
Cu-Mo CLEANER
CONCENTRATE
Cu-Mo
SEPARATION
STANDARD PLANT
..§EPAR
Cu-Mo CLEANER
CONCENTRATE en g
.(.l.).. -o
'""" N
OF
Cu IN SEPLl. FEED
OF
Cu IN SEp!! FEED
OF
Cu IN SEp!! FEED
FIG. I
Cu Cone
81.3%
Mo CIRCUIT
18.7%
Cu Cone.
66.6%
Mo CIRCUIT
33.4%
Cu Cone
91.8%
Mo CIRCUIT
8.2%
..~.
tv
0\
..0. 0
W
00 o
GENERAL FLOWSHEET AND RESULTS ORE B
STANDARD PLANT CONDITIONS
(NO DDM)
c..CJ'.)
~
~
~
~
~a
....
~....
\C
-00
TAILING
OVERY, %
89.0 TO 89.7
86.6 TO 88.3
WITH DDM0.009
Ib/ TON ORE
TO PRIMARY GRIND
PRIMARY
HROUGHER I JSCAVENGER
GRIND J I
REC
Cu-:
Ro - Seov Cone Mo-
REGRIND 8
CLEANING
DDM
~
TAILING
RECOVERY,%
Cu -86.6
Mo-84.0
I -ISCAVENGER
REGRIND 8
CLEANING
ROUGHER
PRIMARY
GRIND
1 1
Cu-Mo Cu-Mo
SEPARATION SEPARATION FIG. 2
Cu-Mo CLEANER
CONCENTRATE
Cu-Mo
SEPARATION
STANDARD PLANT
S-EP-AR-A
Cu- Mo CLEANER
CONCENTRATE en
::r
(l)
-(l) tv
~
tv
OF
Cu IN SEpll. FEED
OF
Cu IN SEpll. FEED
OF
Cu IN SEp!!. FEED
Cu Cone
57.1%
Mo CIRCUIT
42.9%
Cu Cone
32.6%
Mo CIRCUIT
67.4%
Cu Cone
89.0%
Mo CIRCUIT
11.0%
~
\II
N
0\
00
\II
W
00 o
SUMMARY OF THE INVENTION
2
centages for a standard plant pliocess of concentration
and separation, a process employing DDM concentration
and standard separation, and a process employing
DDM concentration and the novel separation proce-
5 dures of the present invention.
4,268,380
1
DRAWINGS
FROTH FLOTATION PROCESS
FIGS. 1 and 2 are general flowsheets illustrating 65
treatment of ores from two different sources, Ore A in
FIG. 1 and Ore B in FIG. 2. In each figure, the flowsheets
compare the treatment steps and recovery per-
The improved process of this invention relates to the
specific separation of metallic sulfide mineral ores com10
prising copper and molybdenum through flotation
This invention relates to an improvement in a froth where an alkyl mercaptan has been used as a collector in
flotation process for concentration and separation of an earlier flotation stage to provide a cleaner concenmetallic
sulfide mineral ores. The improved process is trate having the mercaptan present. The improvement
directed to separations wherein a mercaptan is utilized in the process comprises deactivating the mercaptan,
as a collector in an earlier flotation stage. The improved 15 whereby the subsequent separation flotation stage is
method of this invention includes the addition of acti- removed. The deactivation of the mercaptan is
vated carbon to achieve deactivation of the mercaptan achieved by the addition of an eflfective amount of powprior
to a mineral separation stage and to achieve en- dered activated carbon.
hanced separation of the metallic elements desired. From the drawings, it is clear that an improvement in
Froth flotation is a process commonly employed for 20 the overall yield of copper can be achieved by employseparating,
collecting, and, hence, concentrating valu- ing an alkyl mercaptan collector, 91.5% as compared to
able minerals, particularly sulfide and oxide ores, from 90% in treatment of Ore A,and 89 to 89.7% as comthe
gangue minerals associated with these minerals in pared to 86.6% in treatment of Ore B. Unfortunately,
their ores. The usual steps are as follows:
(a) The ore is crushed andsubjected to wet grinding 25 33.4% of the copper from Ore A and 67.4% of the
to provide a pulp wherein the ore particles are typically copper from Ore B are carried into. the molybdenum
reduced to minus 48 mesh and with about 50% of the circuit when DDM is employed, as compared to 18.7%
particles being in the minus 200.mesh fractions. and 42.9%, respectively, for the previously employed
(b) The ore pulp is generally diluted with water to standard plant procedure. Using the separation ·proceapproximately
30% solids by weight. 30 dure of the present invention to deactivate the DDM
(c) Various conditioning, collecting, and frothing prior to separation, only 8.2% of the copper in Ore A
agents are then added to the mineral pulp. and 11.0% of the copper in Ore B are carried' into the
(d) The pulp is then aerated to produce air bubbles molybdenum circuit, providing a copper concentrate of
that rise to the surface of the pulp and to which the 91.8% for Ore A and 89% for Ore B as compared to
desired mineral particles selectively attach themselves 35 81.3% and 57.1% for the standard plant process.
by virtue of the characteristics of the collectors em- More specifically, the improved process is a method
ployed, thereby permitting removal of these minerals in for recovery of metal values by froth flotation from
a concentrated form. metallic sulfide mineral ores comprising copper and
There are, of course, numerous patents on processes molybdenum, including the steps of:
for froth flotation concentration and separation of min- 40 (A) forming an aqueous mineral pulpfrom the ore:
erals. One such patent is U.S. Pat. No. 2,559,104 (issued (B) subjecting the pulp to rougher flotation to pro-
July 3, 1951) to Arbiter et alwhich relates to a flotation vide a scavenger feed and a rougher concentrate:
recovery method for molybdenite. Arbiter et al teaches (C) adding and effective amount of an alkyl mercapa
specific system in which a collector is oxidized prior tan of the formula HnH2n+ISH in which n is at least 12
to subsequent separation stages. The problem addressed 45 .to the primary flotation stages as a collector and subin
the Arbiter et al patent involves reducing excess jecting the scavenger feed to flotation to provide a
further and excess collector inthe subsequent cleaning scavenger tailing and a scavenger concentrate;
stage. They tend to collect by virtue of the fact that the (D) combining, regrinding, and cleaning the concenbulk
of the collector and frother are carried forward trates from the primary flotation stages (B) and (C) to
into the next cleaning stage. In the Arbiter et al patent, 50
reduction of the excessfrother is accomplished by the i~~:ide a copper molybdenum deaner concentrate; and
addition of the activated carbon as required;
U.S. application Ser. No. 852,413, filed Nov. 17, 1977 (E) subjecting the cleaner concentrate of step (D) to
by Adriaan Wiechers, now U.S. Pat. No. 4,211,644 (the component mineral stage flotation separation; the imspecification
and claims of which arespecifically-incor- 55 provement which comprises deactivating substantial
porated herein by reference) teaches an improved pro- amount of the mercaptan collector on the mineral of the
cess utilizing a mercaptan as a collector, the preferred ore in the cleaner concentrate of step (D) prior to the
mercaptan being normal dodecyl mercaptan ("DDM"). component mineral stage flotation separation in step
As will be seen hereinafter, the use of DDM increases (E), said deactivating comprising adding a deactivating
the overall 'copper recovery from the ore, but at the 60 effective amount of activated carbon to the cleaner
same time can make separation of the copper from the concentrate prior to flotation in step (E); to provide
molybdenite more difficult. more effective mineral separation.
It is preferred that the activated carbon be added
within the range of about 0.25 to about 1.0 pound of
activated carbon per ton of initial ore feed and that it be
added to the cleaner concentrate for a sufficient time
interval prior to step (E) to provide substantial deactivation
of the Illercaptanprior to commencement of step
CROSS REFERENCE TO RELATED
APPLICATION
Thi!\ application is a continuation in part of copending
application Ser. No. 934,132 now abandoned flIed
Aug. IS, 1978.
BACKGROUND OF THE INVENTION
0.014
0.017
0.003
Calculated I
Cu Mo
0.38
0.38
0.34
Mo
0.014
0.018
0.003
1Average assay as calculated from tests
Standard conditions and reagent balance is shown in
Table 2. The reagent balance is substantially identical to
that of current conventional plant practice.
TABLE 2
4,268,380
4
all size fractions from 65- to plus 4OO-mesh with a high
distribution of copper (47%) in the minus 400-mesh (37
micrometers). A relatively constant distribution of molybdenumoccurs
in the coarser size fractions while
67% reports to the minus 400-mesh fraction. The copper
and molybdenum minerals are liberated at a relatively
coarse mesh of grind.
DESCRIPTION OF THE PREFERRED The assays of the three concentrator cyclone over-
EMBODIMENTS flow samples utilized in the examples are as follows:
The process of this invention involves subjecting the 10 TABLE I
ore feed to primary grinding and then rougher flotation, --------.....;;;,;;.;;,=:.::...;;.---------
including the addition of the appropriate reagents, to Assay, %
provide a feed to the scavenger flotation stage after Direct
which the rougher concentrate and the scavenger con- Cu
centrate are combined, subjected to a regrinding, and 15 Sample 3 0.39
then subjected to a number of cleaner flotation stages. Sample 4 0.37
Sample 5 0.35
Prior to commencement of the scavenger flotation
stage, from about 0.005 to about 0.02 pounds per ton ore
of a mercaptan (such as normal dodecyl mercaptan,
"DDM") is added as an auxiliary collector or promoter 20
to provide increased metals recovery during the pri-
3
(E). Such time interval is preferably within the range of
about 5 to 30 minutes.
The invention is particularly applicable to coppermolybednum
sulfide containing mineral ores and is.
quite suited to the typical type of Arizona porphyry 5
ores.
Test Conditions and Reagent Balance
Feed - 4000 grams dry solids cyclone overflow pulp sample
Stage
Reagents Added, IblTon of Ore! Time
Shell Minutes
CaO Z-63 AF-2384 16385 Cond Froth pH
10.7
II.2
11.2
11.2
11.0
0.01 0.005 0.03
0.01
10
0.005 I
II
NaCN/
NaSH ZnS04
1.0
0.25
0.10
0.10
Condition
Rougher
Scavenger
Thicken2
Regrind
1st cleaner
2nd cleaner
3rd cleaner
(NH)4S2
Condition I 11.0 10.
Condition 2 25.0 5
Mo rougher 3 9.3
Mo 1st cleaner 5.0 5 3
Mo 2nd cleaner 2.0 3 2 9.0
1Reagent additions based on Ib/ton of ore with exception of (NH.h S. NaSH, and NaCN/ZnSO additions
which are based on Ib/ton Cu-Mo cleaner concentrate.
2Combine rougher and scavenger concentrates. Thicken to approximately 60% solids.
Jpotassium amyl xanthate
4Sodium di secondary butyl dithiophosphate
585% methyl isobutyl carbinol, !5% distillate bottoms
mary flotation stages. With certain sulfide minerals such
as copper and molybdenum containing ores, the DDM
produces· undesirable effects in the subsequent separation
stage. The process of this invention involves sub- 50
stantially deactivating the DDM prior to the mineral
separation stage.
Ore Sample A
A representative ore sample which is the feed to a 55
concentrator is obtained from a typical producing copper-
molybdenum concentrator located in Arizona.
Copper occurs predominately as chalcopyrite and molybdenum
occurs primarily as molybdenite.
Distribution data for the ore sample show that the 60
copper values are approximately equally distributed on
The most desirable, readily available activated carbon
useful in deactivating the mercaptan collector is of
a relatively high pore surface area of about 0.95 ml per
gram and is a lignite-based powdered activated carbon.
ICI type OFP is particularly useful.
Activated carbon addition is made prior to the sulfidizing
reagent addition in the copper-molybdenum separation
and about 10 minutes allowed for conditioning.
Summarized in Table 3 are the comparative results
illustrating the significant improvement in deactivating
the mercaptan collector (DDM) with the addition of
activated carbon, while the effect of varying levels of
activated carbon is illustrated by the results shown in
Table 4.
TABLE 3
Feed
Sample
No.
Comparison of Effect of General Cu-Mo Separation Processes
Weight Distribution.
Percent Assay, % % Overall
Process Product Overall Cu Mo Cu Mo
2 Standard-plant Mo Ro Conc 0.20 27.9 1.48 18.7 38.8
4,268,380
5 6
TABLE 3-continued
Comparison of Effect of General Cu-Mo Separation Processes
Peed Weighi Distribution,
Sample Percent Assay, % % Overall
No. Process Product Overall Cu Mo Cu Mo
(no DDM) Cu Cone 0.75 26.2 0.07 66.0 7.0
Cu + Mo CI Cone 0.95 26.6 0.37 84.7 45.7
2 Standard-plant' Mo Ro Cone 0.40 25.1 0.86 33.4 43.9
Cu Cone 0.65 24.3 0.06 52.6 4.9
Cu + Mo CI Cone 1.05 24.6 0.36 86.0 48.8
4 Standard-plant' Mo Ro Cone 0.37 25.7 1.19 26.3 36.0
CuCone 0.74 23.8 0.04 54.2 2.3
Cu + Mo CI Cone 1.11 26.2 0.40 80.5 38.3
Activated carbon' Mo Ro Cone 0.20 19.5 2.23 10.0 32.9
(1.0 Ib/ton ore) Cu Cone 1.06 26.0 0.05 71.3 3.9
Cu + Mo CI Cone 1.26 25.0 0.40 81.3 36.8
·0.0075 pound ofDDM addition per ton of ore feed to the scavenger flotation stage
TABLE 4
Effect of Varying Level of Activated Carbon on Cu-Mo Separation
Activated Distribution,
Sample Carbon Weight Assay, % % Overall
No. IblTon Ore Product Percent Cu Mo Cu Mo
2 Mo Ro Cone 0.40 25.1 0.86 33.4 43.9
Cu Cone 0.65 24.3 0.059 52.6 4.9
Cu + Mo CI Cone 1.05 24.6 0.36 86.0 48.8
4 Mo Ro Cone 0.37 25.7 1.19 26.3 36.0
Cu Cone 0.74 23.8 0.035 54.2 2.3
Cu + Mo Cl Cone 1.11 26.2 0.40 80.5 38.3
4 0.25 Mo Ro Cone 0.23 19.9 1.84 13.6 23.3
Cu Cone 0.88 26.0 0.041 67.6 2.0
Cu + Mo CI Cone 1.11 24.7 0.41 81.2 25.3
0.50 Mo Ro Cone 0.22 24.0 2.27 13.9 35.4
Cu Cone 0.94 27.0 0.060 67.1 4.0
Cu + Mo Cl Cone 1.15 26.7 0.48 81.0 39.4
1.0 Mo Ro Cone 0.20 19.5 2.23 10.0 32.9
Cu Cone 1.06 26.0 0.050 71.3 3.9
Cu + Mo Cl Cone 1.26 25.0 0.40 81.3 36.8
4 1.35 Mo Ro Cone 0.20 15.7 2.06 10.9 24.3
Cu Cone 0.86 24.4 0.14 73.3 7.1
Cu + Mo CI Cone 1.06 22.8 0.50 84.2 31.4
4 2.0 Mo Ro Cone 0.18 17.7 1.24 8.9 12.2
Cu Cone 1.07 24.2 0.31 72.7 18.2
Cu + Mo CI Cone 1.25 23.2 0.44 81.6 30.4
IAverage head assays as calculated from all tests
Additional assays were performed on the Sample I head
sample. The results are shown below.
1.77
0.015
0.018
S (Total)
CalculatedI
Pe
Cu Mo
3.05
0.69
0.73
Assay, %
O.oll5
0.OU8
<0.001
NOIllSullide
Mo
Direct
Cu Mo
0.72
0.70
0.060
NonSulfide
Cui
Head Assays - Ore B
Assay, %
1Assay confirmed by two analysts
Sample 1
Sample I
(HRI No. T-229)
Sample 2
(HRI No. T-236)
The results indicate that 0.25 to 0.50 pound activated 45 the standard plant process and 32.6% for DDM with
carbon per ton ore is sufficient to reduce the copper .the standard separation process. Table 9 shows the efdisplacement
in the molybdenum circuit to approxi- fect of varying levels of activated carbon, while Table
mately 13% from approximately 30% without activated 10 illustrates the wise variety of activated carbons
carbon. Increasing the activated carbon level to one which can be employed.
pound per ton ore result in only a marginal further 50
decrease of copper loss in the molybdenum circuit to TABLE 5
about 10%.
Increasing the activated carbon level to greater than
one pound per ton of ore does not appear to significantly
reduce copper loss to the molybdenum circuit, 55
but it may result in reduced molybdenum recovery to
the molybdenum rougher concentrate.
A similar series of experiments were conducted on
another typical 'copper molybdenum ore from a different
location in Arizona, designated for convenience, as 60
Ore B. These experiments developed the data for Tables
5 through 9.
Table 5 contains the head assay, Table 6 sets forth the
reagent balance, and Table 7 the copper-molybdenum
separation reagent balance for the Ore B experiments. 65
Table 8 shows that using activated carbon in the process
of the present invention, the copper concentrate contains
92.5% of the copper as compared with 57.1% for
4,268,380
7 8
TABLE 6
Reagent Balance - Ore B
Reagents Added, IblTon Ore Time,
Fuel Minutes
CaO Sm-S! Oil2 Z_11 3 MIBC4 Cond Froth pH
1.2 0.Q15 0.025 0.05
6 10.0
0.003 0.01 6 9.7
0.2 0.01
Stage
Primary grind
Rougher
Scavenger
ThickenS
Regrind
1st cleaner
2nd cleaner
Stage
Equipment
Speed, rpm
Airflow, IImin
% solids
Rougher-scavenger
Denver D-I, 1000 g cell
1900
-16
35
0.005 I 4
I 3
Ist, 2nd cleaner
Denver D-I, 250 g cell
1200
-6
IS
10.0
9.2
IMinerec Sm-8
2Fuel oil - 50:50 mixture No.2 diesel oil/kerosene
.1Sodium ethyl xauthate
4MIBC - 8S% methyl iosbutyl carbinolllS% MIBC distillation bottoms
5Thickened rougher-scavenger concentrate to approximately 60% solids· decanted (reclaim) water used as
makeup in cleaner stages
TABLE 7
Copper-Molybdenum Separation Reagent Balance
Reagents Added, IblTon Concentrate Feed
Stage
NaCN Na-Ferro K-Ferri
Zn02 H2 023 CN CN NaOCI4 MIBC
Time,
Minutes
Cond Froth pH
8.7-6.7
6.9-6.6
7.0
7.4
7.6
7.7
7.8
8.0
8.1
20
3.75 20
2.0 0.004 I 4
1.0 0.003 I 3
0.20 1.0 I 3
0.10 0.02 I 2
0.10 0.02 I 2
0.10 0.01 I 2
0.10 0.01 1 I~
0.50 0.46
0.20
0.20
Condition I
Condition 2
Mo rougher
Mo 1st cleaner
Mo 2nd cleaner
Mo 3rd cleaner
Mo 4th cleaner
Mo 5th cleaner
Mo 6th cleaner
Condition I, 2 - pulp density 50% solids
Mo rougher - pulp density 20% solids
IAddition based on pounds 100% H2 S04
2NaCN/ZnO· - 5:1 mixture
.130% H202
4S% available CI
TABLE 8
Comparing Cu/Mo Separation With and Without DDM and Activated Carbon
Weight Assay, % Distribution, %
Conditions Product % Cu Mo Cu Mo
Standard separation Mo CI Cone 1.68 13.3 19.6 0.8 51.5
on concentrate withoutDDM
Mo RoConc 35.81 31.6 1.61 42.9 90.7
Cu Cone 64.19 23.4 0.09 57.1 --2:l.
Head (calc) 100.00 26.3 0.64 100.0 100.0
Standard separation Mo CI Cone 8.74 28.9 5.80 9.5 82.8
on concentrate with
DDM Mo Ro Cone 57.39 31.3 1.02 67.4 95.4
Cu Cone 42.61 ,20.4 0.067 32.6 4.6
Head (calc) 100.00 26.7 0.61 100.0 100.0
DDM plus 0.6 Ibsl Mo CI Cone 0.91 13.8 33.7 0.5 57.8
ton ore activated
carbon Mo Ro Cone 6.78 28.0 7.04 7.5 89.8
Cu Cone 93.22 25.1 0.058~ -!Q1..
Head (calc) 100.00 25.3 0.53 100.0 100.0
TABLE 9
Effect of Varying Level of Activated Carbon in Ore B Experiments
Weight Assay, % Distribution, %
Conditions Product % Cu Mo Cu Mo
Standard, no acti- Mo 3rd CI cone 8.74 28.9 5.80 9.5 82.8
vated carbon Mo Ro cone 57.38 31.3 1.02 67.4 95.4
Cu cone 42.61 20.4 0.067 ..lll.. ~
Head (calc) 100.00 26.7 0.61 100.0 100.0
4,268,380
9 10
TABLE 9-continued
Effect of Varying Level of Activated Carbon in Ore B Experiments
Weight Assay, % Distribution, %
Conditions Product % Cu Mo Cu Mo
0.075 Ib activated Mo 3rd.Cl cone 9.23 , 29.2 ·5.30 10.8 81.3
carbon/ton ore Mo Ro cone 38.21 30.8 1.46 47.5 93.8
(1.37 Ib/ton cone) Cu cone 61.79 --RQ... ~ ~ 6.2
Head (calc) 100.00 24.8 0.60 100.0 100.0
0.15 Ib activated Mo 3rd CI cone 3;66 26.4 12.0 3.9 76.5
carbon/ton are Mo Ro cone, 23.84 30.6 2.20 29.5 91.5
(2.73 Ib/ton cone) Cu cone 76.16 ~ 0.064 .2.Q:1... --!1.
Head (calc) 100.00 24.7 0.57 100.0 100.0
0.30 Ib activated Mo 3rd CI cone 2.74 21.2 16.1 2.4 74.7
carbon/ton ore Mo Ro cone 1'6.80 28.9 3.18 19.8 90.5
(5.45 Ib/ton cone) Cu cone 83.20 ~ ~ ~ --2l-
Head (calc) 100.00 24.6 0.59 100.0 100.0
0.60 Ib activated Mo 3rd CI cone 1.77 13.7 23.5 1.0 69.8
carbon/ton are Mo Ro cone 10.73 26.6 4.98 11.6 89.5
(10.91 Ib/ton cone) Cu cone 89.27 24.4 0.070 88.4 -!Q2..
Head (calc) 100.00 24.6 0.60 100.0 100.0
0.90 Ib activated Mo 3rd CI conc 2.60 18.5 15.5 2.0 75.1
carbon/ton are Mo Roconc 11.47 26.9 4.\7 12.6 89.2
(16.38 Ib/ton cone) Cu conc 88.53 24.2 ~ 87.4 ---.!Q:!
Head (calc) 100.00 24.5 0.54 100.0 100.0
1.25 Ib activated Mo 3rd CI conc 2.06 11.5 21.7 1.0 70.4
carbon/ton are Mo Ro conc 10.86 24.8 5.41 11.0 92.6
(22.75/ton conc) Cu conc 89.14 ~ ~ ~ 7.4
Head (calc) 100.00 24.5 0.63 100.0 100.0
TABLE 10
Effect of Type of Activated Carbon (0.6 Pounds Per Ton Ore)
Weight Assay, % Distribution, %
Activated Carbon Product % Cu Mo Cu Mo
Darco-GFP Mo 2nd CI conc 0.91 13.8 33.7 0.5 57.8
Mo Ro conc 6.78 28.0 7.04 7.5 89.8
Cu conc 93.22 ~ ~ ~ -.!Q1..
Head (calc) 100.00 25.3 0.53 100.0 100.0
Darco-FM-I Mo 3rd CI conc 1.16 10.5 28.4 0.5 67.1
Mo Ro conc 7.30 26.2 6.17 7.5 91.7
Cu conc 92.70 ~ 0.044 ~ 8.3
Head (calc) 100.00 25.5 0.49 100.0 100.0
Calgon-PCB Mo 3rd CI conc 2.57 18.3 17.0 1.9 78.4
Mo Ro conc 13.13 28.6 3.99 15.0 93.9
Cu conc 86.87 ~ ~ -lliL --il
Head (calc) 100.00 25.3 0.56 100.0 100.0
Union Carbide-LCK Mo 3rd CI conc 2.40 14.0 18.5 1.3 74.0
MoRa conc 11.70 27.6 4.75 12.8 92.6
Cu conc 88.30 25.0 ~ -EL 7.4
Head (calc) 100.00 25.3 ,0.60 100.0 100.0
Norit-RO 0.8 Mo 3rd CI conc 1.33 5.52 31.3 0.3 67.5
Mo Ro conc 10.80 26.4 5.35 11.2 93.7
Cu conc 89.20 ~ ~ -1ll. ~
Head (calc) 100.00 25.5 0.61 100.0 100.0
Sethco-powdered Mo 3rd CI conc 4.30 23.1 9.92 3.9 76.9
Mo Ro cone 18.00 29.8 2.85 21.0 92.3
Cu conc 82.00 ~ ~ 79.0 7.7
Head (calc) 100.00 25.4 0.56 100.0 100.0
Measurements were made of the oxidation-reduction
potential (emf) of the pulp just prior to molybdenum
rougher flotation, These measurements were made at
various levels of activated carbon and the results are set
forth in Table 11.
Reference was made hereinbefore to U.S. Pat. No. 55
2,559,104 to Arbiter et at which teaches the oxidizing of
a collector prior to the subsequent separation stages,
and the use of activated carbon to reduce excess frother
and. excess collector in the subsequent cleaning stages.
While appafently similar to the process of the present 60
invention, the chemical route taught by Arbiteret al is,
in fact, exactly opposite to that employed in the process
of the present invention. Thus while Arbiter et al
teaches the use of an oxidizing agent to deactivate the
collector, the process of the present invention employes 65
activated carbon to deactivate the collector, and there is
strong evidence that in so doing, the activated carbon
acts as a reducing agent.
TABLE 1M
Pounds Activated Carbon
Per Ton Ore
0.00
0,075
lJ5
0.30 .
0.60 '
0.90
Pulp emf,
-mv
380
360
300
260
190
180
12
scope of the present invention, and it is my intention to
be limited only by the appended claims.
What is claimed:
1. In the method for recovery of metal values by froth
5 flotation from metallic sulfide mineral ores comprising
copper and molybdenum, including the steps of:
(A) forming an aqueous mineral pulp from the ore;
(B) subjecting the pulp to rougher flotation to provide
a scavenger feed and a rougher concentrate;
(C) adding an effective amount of an alkyl mercaptan
of the formula CnH2n+ISH in which n is at least 12
to the rougher flotation stage (B) or to the scavenger
feed resulting therefrom, as a collector, and
subjecting the scavenger feed to flotation to provide
a scavenger tailing and a scavenger concentrate;
(D) combining, regrinding, and cleaning the concentrates
from the rougher and scavenger flotation
states (B) and (C) to provide a copper-molybdenum
cleaner concentrate; and then
(E) subjecting the cleaner concentrate of step (D) to
component mineral stage flotation separation; the
improvement which comprises deactivating a substantial
amount of the mercaptan collector on the
4,268,380
160
190
230
170
Pulp emf,
-mv
11
TABLE II-continued
1.25
Pounds Activated Carbon
Per Ton Ore
In addition, it has been found that sodium zinc cyanide,
which was heretofore considered to be an essential
reagent to the process, can be omitted. A further series
of tests were conducted in which the emf was measured 10
on a series of pulps wherein the sodium zinc cyanide
was omitted, the level of activated carbon was maintained
constant, and only the conditioning time was
varied. The data developed in these further tests are set
forth in Table 12, while the distribution of copper and 15
molybdenum is described in Table 13.
TABLE 12
0.60 Ib Activated Carbon Pulp emf,
/Ton Ore -mv
------------------- 20
(20 minute A.C. cond time)
(10 minute A.C. cond time)
( 5 minute A.C. cond time)
TABLE 13
Effect o(Elimination of Sodium Zinc Cyanide
Weight Assay, % Distribution, %
Condition Product % Cu Mo Cu Mo
Standard, with Mo 3rd CI conc 1.77 13.7 23.5 1.0 69.8
NaZnCN 0.60 Ib A.C. Mo Ro conc 10.73 26.6 4.98 11.6 89.5
/ton ore to Cond 1 Cu conc 89.27 24.4 0.070 ~ --lQ:i.
Head (calc) 100.00 24.6 0.60 100.0 100.0
0.60 Ib A.C./ton ore Mo 3rd CI conc 1.13 12.7 29.7 0.6 65.8
No NaZnCn' Mo Ro conc 9.03 29.7 5.10 10.4 90.2
Cu conc 90.97 ~ 0.055 89.6 --..2:!
Head (calc) 100.00 25.7 0.51 100.0 100.0
No activated carbon Mo Ro Conc 45.97 30.2 1.38 54.3 96.4
No NaZnCN Cu conc 54.03 ....1.!&. 0.044 ~ -1i.
Head (calc) 100.00 25.6 0.66 100.0 100.0
The data in Tables 11 and 12 clearly indicate that as
the level of activated carbon increased, and/or as the
conditioning time increased for a fixed level of carbon, 45
the emf of the pulp decreased. In other words, the net
effect of the treatment with activated carbon was to
achieve a reduction reaction as evidenced by these
substantially lower emf measurements.
Though not willing to be bound by anyone theory by 50
which the functioning of the activated carbon might be
explained, at least one possible mechanism is that the
activated carbon functions by desorption of oxygen
from the collector-mineral surface bond to render a
given sulfide mineral hydrophillic. Desorption of the 55
oxygen from the sulfide minerals surface would render
collector inactive, and therefore,' the mineral particle
hydrophillic. In a copper molybdenum separation, the
action of the activated carbon is apparently specific to
copper and iron sulfide minerals rendering these less 60
floatable than the molybdenite, while it very surprisingly
does not appear to cause desorption of oxygen
and/or collector from the molybdenite surface and the
molybdenite, therefore, continues to be hydrophobic.
It will, of course, be obvious to those skilled in the 65
art, that many changes and substitutions,can be made in
the specific materials, reactants, and procedural steps
set forth hereinbefore, without departing from the
mineral of the ore in the cleaner concentrate of step
(D) prior to the component mineral stage flotation
separation in step (E), said deactivating comprising
adding a deactivating effective amount of activated
carbon to the cleaner concentrate prior to flotation
in step (E); to provide more effective mineral separation
of said copper and molybdenum.
2. The method as defined in claim I, wherein the
amount of activated carbon is within the range of about
0.25 to about 1.0 pound of activated carbon per ton of
initial ore feed.
3. The method as defined in claim 1, wherein the
activated carbon is added to the cleaner concentrate a
sufficient time prior to step (E) to provide substantial
deactivation of the mercaptan prior to commencement
of the step (E) separation stage.
4. The method as defined in claim 3, wherein the time
prior to step (E) separation stage is within the range of
about 5 minutes to about 30 minutes.
5. The method as defined in claim 1, wherein the
mercaptan is normal dodecyl mercaptan.
6. The method as defined in claim 5, wherein said
mercaptan is added in an amount within the range of
about 0.005 to about 0.02 pounds per ton of ore.
7. The method as defined in claim 6, wherein the
amount of activated carbon added is within the range of
about 0.25 to about 1.0 pound per ton of initial ore feed. * * • • .,
UNITED STATES PATENT AND TRADEMARK OFFICE
CERTIFICATE OF CORRECTION
PATENT NO.
DATED
INVENTOR(S)
4,268,380
May 19, 1981
DOULGAS R. SHAW
It is certified that error appears in the above-identified patent and that said Letters Patent
is hereby corrected as shown below:
IN THE DRAWINGS
At each location at the bottom of Fig. 1 and Fig. 2
(a total of six places), change "Mo CIRCUIT" to read
--Mo Ro Conc--.
~jgncd and ~calcd this
Fourth Day of Augllst1981
ISEAL)
Att,st:
GERALD J. MOSSINGHOFF
Commissioner of Patents and Trademarks
r------------------------------------------...,
UNITED STATES PATENT AND TRADEMARK OFFICE
CERTIFICATE OF CORRECTION
PATENT NO.
DATED
INVENTOR(S)
4,268,380
May 19, 1981
DOUGLAS R. SHAW
It is certified that error appears in the above-identified patent and that said Letters Patent
is hereby corrected as shown below:
Column 1, line 47, delete "further" and insert --frother--.
Column 2, line 17, delete "removed" and insert --improved--j
line 43, delete "and" and insert --an--j
line 44, correct the formula to read --CnH2n+1SF--.
Column 3, line 2, after "to" insert --about--.
Column 12, claim 1, line 19, "states" should read --stages--.
5igncd and 5calcd this
First Day of September /98/
{SEAL\
GERALD J. MOSSlNGHOFF
Commissioni!r of Patents and Trademarks