4,268,380 Froth flotation process

Patent Number/Link:

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

Cu IN SEPn. FEED

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

0"0

s::

.Vl

0/0

IROUGHER I iSCAVENGER ~"'''IAILII'''''

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

: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

Cu IN SEPLl. FEED

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%

..~.

..0. 0

00 o

GENERAL FLOWSHEET AND RESULTS ORE B

STANDARD PLANT CONDITIONS

(NO DDM)

c..CJ'.)

....

~....

-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

Cu IN SEpll. FEED

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

00 o

SUMMARY OF THE INVENTION

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

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

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

0.34

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

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-

(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

11.0

0.01 0.005 0.03

0.01

0.005 I

NaCN/

NaSH ZnS04

1.0

0.25

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

Cu Mo

3.05

0.69

0.73

Assay, %

O.oll5

0.OU8

<0.001

NOIllSullide

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

0.005 I 4

I 3

Ist, 2nd cleaner

Denver D-I, 250 g cell

1200

-6

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

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 0.01 I 2

0.10 0.01 1 I~

0.50 0.46

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

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;

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

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