8 Oaims, No Drawings
Molybdenite is recovered by froth flotation of ore or
concentrate by use of thio carboxylic acid compound
and activated carbon to depress copper and other metal
sulfides. The reagents are preferably utilized in a weight
ratio of about 1:1.
3,400,817 9/1968 Burwell 209/167
3,785,488 1/1974 Werneke 209/167
3,811,569 8/1974 Shirley 209/167
4,196,073 4/1980 Gannon 209/167
4,231,859 11/1980 Huiatt 209/167
4,268,380 5/1981 Shaw 209/167
FOREIGN PATENT DOCUMENTS
358460 4/1930 United Kingdom 209/167
373662 6/1932 United Kingdom 209/167
Primary Examiner-Robert Halper
Attorney, Agent, or Firm-James R. Thornton
United States Patent [19]
Ramadoraiet ale
[54] FLOTATION OF MOLYBDENITE
[75] Inventors: Gopalan Ramadorai, Fullerton,
Calif.; Douglas R. Shaw, Tucson,
Ariz.
[73] Assignee: United States Borax & Chemical
Corporation, Los Angeles, Calif.
[21] Appl. No.: 111,434
[22] Filed: Jan. 11, 1980
[51] Int. 0.3 B03D 1/06
[52] U.S. O 209/167
[58] Field of Search 209/167, 166
[56] References Cited
U.S. PATENT DOCUMENTS
1,261,810 4/1918 Hebbard 209/167
2,449,984 9/1948 Gibbs 209/167
2,559,104 7/1951 Arbiter 209/167 X
2,957,576 10/1960 Henderson 209/167
[57]
[11]
[45]
ABSTRACT
4,329,223
May 11,1982
DESCRIPTION OF THE INVENTION
EXAMPLE 1
Molybdenite ore (18 kg.) assaying 0.265% MoSz and
0.0035% Cu as calcopyrite was ground to about 22%
+100 mesh, treated with known grinding and flotation
reagents and submitted to a rougher and scavenger
flotation procedure. The rougher concentrate was reground
at 50% solids and refloated to give a first
cleaner concentrate containing about 0.18% Cu. The
resultant concentrate was reground, reagentized, condi-
2
use of activated carbon or charcoal in conjunction With
Nokes reagent in a process for the recovery ofmolybdenite
by froth floation.
4,329,223
1
FLOTATION OF MOLYBDENITE
SUMMARYOFTHE INVENTION
BACKGROUND OF THE INVENTION
This invention provides a process of froth flotation
for the separation ofmolybdenite from copper, iron and
similar metal sulfides by use of a combination of acti- 45
vated carbon and a thio carboxylic acid compound as
flotation reagents. Such combinations of reagents are
used in a weight ratio of about 1:1.
This invention relates to the flotation recovery of
molybdenite and especially to the depression of undesir- 5
able metal sulfides in the froth flotation of molybdenite. The reagent combination of the present invention
includes a thio carboxylic acid which may be defined by
the formula HS-R-COOH or HS-R-COSH in which R
A major source of molybdenum metal is the mineral represents an aliphatic hydrocarbon group having from
molybdenite (MoSz) which occurs frequently as a con- 10 1 to about 5 carbon atoms or the group CO. Such comstituent
of other metal sulfide ores or may occur as a pounds are described in Gibbs' U.S. Pat. No. 2,449,984
primary molybdenite ore with only minor amounts of and include compounds such as thioglycollic acid, alother
metal sulfides. Frequently, molybdenite is a minor pha-mercaptobutyric acid, alpha-mercaptocaproic acid,
constituent of copper sulfide ores, and a major source of and dithio oxalic acid. The compounds are conveniently
molybdenite in the United States is as a by-product of 15 used in the form of their water-soluble salts such as the
copper ore processing in which the molybdenite is sepa- sodium and potassium salts. The presently preferred
rated from the copper and other sulfide constituentsby thio carboxylic acid is thioglycollic acid, also known as
a froth flotation procedure. Molybdenite is also ob- mercaptoacetic acid, especially as the salts, sodium
tained from primlll'Y molybdenit~ ores by use of a series thioglycollate or potassium thioglycollate.
of froth flotation procedures to obtain a concentrate 20 The activated carbon or charcoal is well-known to
high in molybdenum sulfide but containing minor the art and is readily available from several industrial
.amounts of copper sulfide contaminant. Such copper is sources. The activated carbon is conveniently used in
undesirable since the molybdenite concentrate is usually the form of an aqueous slurry and is employed in a
converted to molybdenum oxide or ferromolybdenum fmely divided form such as of about 200 to 400 mesh
for use by the iron and steel industry which requires the 25
copper contentto be low, generally lessthan 1%. size. According to the process of the present invention,
According to the present practice of the industry, the activated carbon is added to the flotation pulp prior
undesirable metal sulfides such as copper and iron sul- to addition of the thio carboxylic acid.
fide are controlled by use of sodium cyanide or Nokes The combination of reagents of this invention are
reagent as a depressant in the froth floj:ation procedure. 30 preferably employed in a weight ratio of about 1:1 with
However, the toxic nature of the cyanide makes it unat- the amounts required being dependent upon the copper
tractive because of its potential.adverse environmetal sulfide content of the ore or concentrate being treated.
effects. Nokes reagent, which is produced by reaction Thus, when a copper sulfide ore having a minor amount
of phosphorous pentasu1fide with caustic soda also pres- of molybdenite is subjected to flotation, a much larger
ents problems sinc~ toxic hydrogen sulfide gas is pro- 35 amount of reagent is required. If the ore is a primary
duced as a by-product. The present invention provides molybdeniteore or molybdenite concentrate containing
a novel combin~tion of reagents which depress copper small amounts of copper sulfide, lesser amounts of reaand
other metal sulfides in the froth flotation of molyb- gents are required to depress the copper and other metal
denite without. the above undesirable environmental sulfides. Thus, according to the present invention, about
side effects. .. 40 0.001 to 0.01 lb. of the thio carboxylic acid reagent is
used for each pound of copper in the ore or concentrate
being subjected to flotation, with about 0.005 lb. being
preferred. A similar amount of activated carbon is also
used since best results are obtained when the weight
ratio of the reagents is about 1:1.
As described above, the activated carbon is added
and the flotation pulp is conditioned prior to addition of
the thio carboxylic acid. The flotation procedure takes
place at about ambient temperature using flotation pro-
PRIOR ART 50 cessing equipment well-known to those skilled in the
Gibbs, U.S. Pat. No. 2,449,984, describes the use of a art. Other well-known flotation reagents may be used,
series of thio carboxylic acid compounds as depressants including frothers such as methyl isobutyl carbonol,
for copper and iron sulfides in the froth flotation of pine oil and the Dowfroth products, collectors such as
molybdenite. Such compounds are defmed as having diesel oil and vapor oil, flocculants, emulsifiers, disperthe
formula HS-R-COOH or HS-R-COSH in which R 55 sants, pH modifiers and other depressants.
represents a saturated aliphatic group or the group CO. The following examples illustrate the process of the
Arbiter and Young, U.S. Pat. No. 2,559,104, and Huiatt present invention. In each example, the amount of reaet
al., U.S. Application Ser. No. 900,830, ftled Apr. 28, gent added is expressed as per ton of ore.
1978 (published by the National Technical Information
Service as PB-282 977), describe. the use of activated 60
carbon or charcoal in the froth flotation of molybdenite
and separation ofcopper sulfide therefrom. According
to Arbiter et al., the activated carbon is used in conjunction
with an oxidizing agent such as the hypocWorites
and peroxides. According to Huiatt et aI., the activated 65
carbon is employed in a froth flotation process in combination
with the. injection. of steam into the flotation
pulp. Henderson, U.S. Pat. No. 2,957,576, discloses the
4,329,223
3 4
tioned and submitted to five cleaner flotation procedures
as outlined below:
Reagents Added, PoundslTon of are
Stpfl. Diesel Pine
Stage Na2Si03 ZnS04 85L Oil Oil MIBC Lime
Primary Grind 0.50 0.020 0.140 0.027 0.027
Rougher Float 0.030 0.033
Scavenger Float 0.020 0.016
1st Regrind
1st Cleaner Float 0.036
2nd Regrind 0.100 0.200
2nd Cleaner Float 0.034 0.001 0.044
3rd Cleaner Float 0.050 0.100 0.030
3rd Regrind 0.025 0.050
4th Cleaner Float 0.030 0.001
5th Cleaner Float 0.QI5 0.030 0.020 0.001 0.014
6th Cleaner Float 0.010 0.020 0.020 0.002
Total 0.700 0.400 0.020 0.360 0.027 0.046 0.093
TABLE I-continued
5 Carbon 0.032 Ib./ton ) 78.7 87.7 0.032 0.20
Concentrate
Ex- MOS2% Concentrate
am- Re- Grade (%)
pie Reagents -covery MoS2 Cu Fe
NTG 0.035 Ib./ton
6 Carbon 0.036 Ib./ton ) 61.4 91.6 0.010 0.17
NTG 0.065 Ib./ton
EXAMPLE 5
EXAMPLE 4
TABLE I
Concentrate
Ex- MOS2% Concentrate 65
am- Re- Grade (%)
pie Reagents covery MOS2 Cu Fe
1 Control 72.1 89.8 0.130 0.37
Z Carbon 0.04 Ib./ton 75.7 88.4 0.095 0.29
3 NTG 0.035 Ib./ton 63.6 86.7 0.050 0.35
4 NTG 0.065 Ib./ton 62.0 90.4 0.QI5 0.20
25
EXAMPLE 2
MIBC is methyl isobutyl carbinol. 20
Stpfl. 85L is Stepanflote 85L, an organic sulfur contain- ---------------------
ing surfactant which is recommended for flotation of
molybdenite.
The results are shown in Table I.
EXAMPLE 6
The procedure of Example 5 was followed except
0.036 pound/ton ore of activated carbon and 0.065
pound/ton ore of sodium thioglycollate were added.
The results are shown in Table I.
The procedure of Example 1 was followed except
0.032 pound/ton ore of activated carbon was added and 50
the reagentized pulp conditioned for 5 minutes and then
0.035 pound/ton ore of sodium thioglycollate added
prior to the 2nd through-4th cleaner flotation stages.
The results are recorded in Table I.
EXAMPLE 3
The procedure of Example 1 was repeated except 35
0.035 pound of sodium thioglycollate per ton of ore was
added prior to the 2nd through 6th cleaner flotation
stages. The results are shown in Table I.
The procedure of Example -I was repeated except
0.065 pound of sodium thioglycollate per ton ofore was
added prior to the 2nd through 6th cleaner flotation
stages. The results are shown in Table I. 45
The procedure of Example 1 was repeated except
0.04 pound of activated carbon per ton ofore was added
prior to conditioning and flotation in the 2nd through 30
4th cleaner flotation stages. The results are shown in :-=-:---:-~~~~---------------
Table I. NTG = sodium thioglycollate
As shown in Table I, when activated carbon"is added
(Example 2), the MOS2 recovery is increased and the
copper and iron content of the concentrate reduced.
The addition of NTG (Examples 3 and 4) further reduces
the Cu and Fe, but the MoSz recovery is also
reduced. The 1:1 combination of carbon andNTG (Example
5) gives a high recovery of MOS2 with, low Cu
40 and Fe content. Although a 1:2 combination of carbon
and NTG (Example 6) further reduces the Cu and Fe
content of the MOS2 concentrate, the recovery is also
lowered substantially. Thus, the 1:1 combination of
Example 5 gave an acceptable grade of MOS2 concentrate
with good Cu and Fe levels and good MoS2recovery.
Various changes and modifications of the invention
can be made, and to the extent that such variations
incorporate the spirit of this invention, they are intended
to be included within the scope of the appended
claims.
What is claimed is:
1. The method _for recovering molybdenite from a
flotation concentrate containing primarily molybdenite
55 and minor amounts of sulfides of copper and iron which
comprises conditioning said concentrate in aqueous
suspension with first about 0.001 to 0.01 pound of activated
carbon and then about 0.001 to 0.01 pound of a
thio acid of the formula HS-R-COOH or HS-R-COSH
60 or soluble salt thereof and subjecting the suspension of
conditioned concentrate to froth flotation at ambient
temperature for the recovery of said molybdenite,
wherein R represents an aliphatic hydrocarbon group
having 1 to about 5 carbon atoms or the group CO, the
weight ratio of said carbon and said thio acid is about
1:1 and said pounds of said carbon and said thio acid are
per pound of copper in said concentrate.
2. The method according to claim 1 in which said thio
acid salt is sodium thioglycollate.
3. The method according to claim 1 in which about
0.005 pound of activated carbon and about 0.005 pound
4,329,223
5
ofsaid thio acid or salt thereof are added for each pound
of copper in said concentrate.
4. The method of claim 1 in which said thio acid salt
is potassium dithio oxalate.
5. In the method for separating molybdenite from 5
copper sulfide by the froth flotation of an aqueous suspension
of molybdenite concentrate containing a minor
amount of copper sulfide, the improvement which comprises
conditioning said concentrate with, first, activated
carbon and, second, a thio acid or soluble salt 10
thereof, and subjecting said conditioned concentrate to
froth flotation at ambient temperature, wherein about
0.001 to 0.01 pound of said activated carbon per pound
of copper in said concentrate and about an equivalent
6
amount of said thio acid or salt thereof are employed
and wherein said thio acid has the formula HS-RCOOH
or HS-R-COSH in which R represents an aliphatic
hydrocarbon group having from 1 to about 5
carbon atoms or the group CO.
6. The method according to claim 5 in which said thio
acid salt is sodium thioglycollate.
7. The method according to claim 6 in which about
0.005 pound each of said activated carbon and sodium
thioglycollate are employed for each pound of copper
in said concentrate.
8. The method according to claim 5 in which said thio
acid salt is potassium dithio oxalate. . ••• * •
15
20
25
30
35
40
45
50
55
60
65