Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
30984CA
~2~
ORE FLOTATION WITH COMBINED FLOTATION AGENTS
This invention relates to mineral recovery by flotation
operations. More specifically the invention relates to a new composition
comprising two or more flotation ingredients. Another aspect of this
invention relates to an ore flotation process, particularly an ore
flotation process in which iron, copper, lead or zinc are recovered.
Background of the Invention
Flotation processes are known in the art and are used for
recovering and concentrating minerals from ores. In froth flotation
processes the ore is crushed and wet ground to obtain a pulp. Additives
such as mineral ~lotation or collecting agents, frothers, suppressants,
stabilizers, etc. are added to the pulp to assist separating valuable
materials from undesirable or gangue portions of the ore in subsequent
flotation steps. The pulp is then aerated to produce a froth at the
surface. The minerals which adhere to the bubbles or froth are skimmed
or otherwise removed and the mineral bearing froth is collected and
further processed to obtain the desired minerals. Typical mineral
flotation collectors include xanthates, amines, al~yl sulfates, arene
sulfonates, dithiocarbamates, dithiophosphates, and thiols.
While the art of ore flotation has reached a significant degree
of sophistication it is a continuing goal in the ore recovery industry to
increase the productivity of ore flotation processes and above all to
provide specific processes which are selective to one ore or to one metal
over other ores or other metals~ respectively~ which are present in the
treated material.
5;7~;
The Invention
It is thus one object of this invention -to provide a new
composition which is useful in ore flotation.
Another object of this invention is to provide a flotation
process.
Yet a further object of this invention is to provide an
improved flotation process using the new composition to improve the
recovery of iron and/or copper as well as lead and/or zinc from ores
containing metals, particularly sulfided ores.
These and other objects, advantages, details, features and
embodiments of this invention will become apparent to those skilled in
the art from the following detailed description of the invention and the
appended claims.
In accordance with this invention it has now been found that a
composition comprising a n-butyl alkali metal trithiocarbonate and a
lower alkyl alkali metal trithiocarbonate to be defined together
constitute a new composition which is useful particularly as a ~lotation
and collecting agent in the recovery of iron and/or copper as well as
lead and/or zinc.
Thus in accordance with a first embodiment of this invention a
novel composition of matter is provided which comprises and preferably
consists essentially o~ substantial amounts of each of the ~ollowing
compounds:
(a) a first composition being an alkali metal n-butyl
trithiocarbonate having the formula
S
M-S-C-S-CH -CH -CH -C~
~herein M is sodium or potassillm, or being a mixture of these compounds,
30~b) a second composition being an alka].i metal alkyl
trithiocarbonate having the formula
S
M-S-C-S-R
wherein M is sodium or potassium and R is ethyl, n-propyl or isopropyl,
or being a mixture o two or three of these compounds.
The preferred composition comprises the above-deined materials
as the sodium salts, in other words, in the preferred flota~ion agent M
is sodium.
The ore flotation agent in accordance with this invention
contains the above ingredients pre~erably in relative quantities as
follows:
(a) 50 to 98 wt. % of said first composition,
(b) 50 to 2 wt. % of said second composi-tlon,
said weight percentages being based on the total weight of said first and
said second composition combined as 100 weight percent.
The flotation agent of this invention is generally employed as
an aqueous solu~ion. The preferred composi~ion of such an aqueous
solution of the flo~ation agent is as follows:
60 parts by weigh-t of water
20 to 39.2 parts by weight of said first composition
20 to .8 parts by weight of said second composition
In addition, the ore flotation agent of this invention can be admixed
with frothers, suppressants and stabilizers as mentioned above. These
additional ingredients are used in quantities commonly employed in this
art. Examples of frothers that can be used in addition to the collector
compositions defined above are polyo~y alkylene glycols and ethers having
broadly a molecular weight of 400 to about 1000, and preferably a
molecular weight in the range of about 420 to 780. Particularly
polypropylene glycols having molecular weights of e.g., 400, 425, 750 or
900 can be used. Also polybutylene glycol and polypentylene glycol are
useful materials. ~xamples of other frothers that may be used are methyl
isobutyl carbinol, pine oil, alcohols, phenols, fatty acids and cresylic
acid.
Suppressants which can be used in combination with the
collector compositions defined above are sodium cyanide, sodium sulfide,
lime, zinc sulfate, starch, glue and sulfuric acid to name just a few.
Both the n butyl trithiocarbonate composition and the lower
; alkyl trithiocarbonate composition are present in the ore flo-tation agent
of this invention in a substantial quantity. While the preferred weight
ranges have been given above, the term "substantial" as used herein is
7~
intended to describe a ~uan-tity of each composi-tion but is large ~nough
to change or modify at least one flotation process parameter as compared
to using only the other composition of the flotation agent.
Particularly, a "substantial" amount of each composition is present if
the recovery of a specific ore achieved by the combined agent is larger
than the recovery activity or efficiency of the other agent alone.
he ~irst Composition
The first composition is an alkali metal n-butyl trithio-
carbonate as defined. Most preferably it is a sodium metal n-butyl
trithiocarbonate. Said first component can also be a mix-ture of the
sodium and potassium n-butyl trithiocarbonate.
The Second Composition
The second composition present in the flotation agent of this
invention is an alkali metal C2 3 alkyl trithiocarbonate. In the
flotation agent of this invention, the sodium salt is preferred. For the
flotation of iron and/or copper the isopropyl alkali trithiocarbonate is
particularly advantageously used. The n-propyl alkali metal trithio-
carbonate and the ethyl alkali metal trithiocarbonate as well as Mixtures
of these two compositions are specifically suited for the flotation of
lead and/or zinc ores.
_lotation Process
In accordance with another embodiment of this invention a
flotation process is provided. This flotation process lnvolves the steps
of
(a) mixing the mineral material with water and the composition
defined above to establish a pulp,
(b) aerating the pulp to produce a froth and a tail product,
(c) separating the froth and the tail product and
(d) recovering minerals from the so separated froth and/or
tail product.
The process steps here involved are conventional except for the
novel composition used as collector in combination as defined above.
Although the two compositions can be added separately during the froth
flotation, and can be added either to the grind stage of the minerals or
to a float, it is Rreferred that the ingredients be premixed, blended or
otherwise combined before using.
`` ~2~57~
Metal Bearing Ores
The composition of this invention is useful for a variety of
minerals. The composition is, however, particularly useiul for
recovering mineral values from sulfided ores.
For the recovery of iron and/or copper values from such ores
the isopropyl trithiocarbonate salt in combination with the n-butyl
trithiocarbonate salt is particularly useful. For lead and/or zinc
recovery the ethyl and normal prop~l trithiocarbonate salt (or both)
in combination with the n-butyl tri-thiocarbona-te salt have proven to be
advantageous.
The amount of the two collector compositions as defined above
employed will generally be from a total about 0.005 lbs/ton of ore to 0.5
lbs/ton of ore (or concentrate or other mining deposit as the case may
be).
Examples of ores for which the flotation of this invention and
the process of this invention can be utilized are listed in the
following:
Copper-Bearing Ores:
Covellite CuS 2Fe~S7 or Cu3Fe4s7
Chalcocite Cu2S Cuprite Cu2O
Chalcopyrite CuFeS2 Tenorite CuO
Bornite Cu5FeS4 Chrysocolla CuSi08
Cubanite Cu2SFe4S5 Bournonite PbCuSbS3
~ead-Bearing Ores:
Galena PbS
Zinc-Bearing Ores:
Sphalerite ZnS
Zincite ZnO
Smithsonite ZnCO3
30 Iron-Bearing Ores:
Ma8netite FeO, Fe2O3
Pyrite FeS2
Pyrrhotite Fe5S6 to Fel6S17
.
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In accordance with a second embodiment of this invention it has
been discovered that iron and copper recovery are high when a flotation
agent is utilized which comprises a substantial amount of both of the
following ingredients:
~a) a first composition having the formula
S
Il
M-S-C-S-CH -CH -CH -CH
wherein M is sodium or potassium, or being a mix-ture of these compounds,
(b) a second composition being a com~ound having the formula
M--S-C-O-C5H11
wherein M is sodium or potassium, or being a mixture of such compounds.
The slkali metal n-butyl trithiocarbonate and the alkali metal
amyl xanthate are preferably employed in ~eight ranges shown in the
following:
16:2~i parts by weight of said first composition
84:76 parts by weight of said second composition
The total weight of said first and said second composition combined being
100 parts by weight.
The flo-tation agent of the second embodiment of this invention
also preferably is provided for and used as an aqueous solution. As such
the agent comprises
(a) 60 parts by weight of water,
(b) 8 to 15.7 parts by weight of said Eirst composition,
(c) 32 to 24.3 par-ts by weight of said second composition,
being said xanthate.
The present invention also relates to a flotation process
utilizing the flotation agent of the second embodiment of this invention.
The preferred conditions and steps of the flotation agent ~or this
embodiment are essentially the same as those described above, except that
the flotation agent used is the trithiocarbonate and xanthate containing
flotation agent defined infra. This process is particularly applicable
for the recovery of iron and/or copper values from mineral containing
such values, particularly from sulfided ~inerals.
~5~
The following examples serve to further illustrate the
invention as well as to show further preferred embodiments thereof
without undue limitation of its scope.
Example I
This example describes a typical procedure used herein to
evalua-te ore flotation agents. The example includes an inventive run
whereby a trithiocarbonate is used along with a known xanthate-type
mineral collector and a control run where two known mineral collectors,
xanthate and a dithiophosphate, are used. To a ball mill was added 1100
grams of a Fe-, Cu-containing ore (Disputada Ore, Chile) along with 1000
milliliters tap water, and 2.5 grams lime and the mixture ground for 5.5
minutes. The slurry was transferred -to a 2.5 Liter Denver~ D-12
flotation cell along with enough water to fill the cell to 1 inch from
the lip (about 35 wt. % aqueous solids). Also added to the cell while
stirring the contents a-t 1000 rpm was 1 drop of frother (methyl isobutyl
carbinol), 0.07 lb/ton sodium di-sec-butyl dithiophosphate (AC238~,
American Cyanamid) and 0.058 lb/ton potassium amyl xanthate (Z-6). The
mixture was conditioned for 1 minute and floated for 10 minutes. The
floa-ted concentrate was filtered, dried and analyzed. The procedure was
repeated except instead of using the AC238 and Z-6 collector combination
there was used as the collector combination 0.058 lb/ton potassium amyl
xanthate (Z-6) and 0.07 lb/ton sodium n-butyl trithiocarbonate. The
results listed in Table I show the inventive composition, potassium amyl
xanthate and sodium n-butyl trithiocarbonate, gives an increase in Fe
and Cu recoveries.
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57~
Table I
EE~ect of Collector Blends on % Recovery
1100 grams Ore
Run % Recovery
No. Collector (0.128 lb/ton)Fe Cu
Control:
1 54.6% Dithiophosphatea ~ 45.4% Xanthateb41.11 80.47
2 5~.6% Dithiophosphatea -~ ~15.4% Xanthateb 44.38 77.54
Average = 42.75 79.01
10 Invention:
354.6% TrithiocarbonateC + 45.4% Xanthateb 43.39 79.91
454.6% TrithiocarbonateC~ 45.4% Xanthateb 45.81 80.40
Average = 44.60 80.16
aAC-238, sodium di-sec-butyl dithiophosphate (1% aqueous solution).
bZ-6, potassium amyl ~anthate (1% aqueous solution).
C1% aqueous solution of sodium n-butyl trithiocarbonate.
Example II
This example illustrates the effectiveness of combinlng two
different trithiocarbona-tes as a collector. The procedure described in
~xample I was repeated except the collectors used were sodium isopropyl
trithiocarbonate and sodium n-butyl trithiocarbonate. The results which
are listed in Table II show an increase in the % recovery oE Fe and Cu
when the sodium isopropyl trithiocarbonate and sodium n-bu-tyl trithio-
carbonate are used together as compared when each collector is used
separately. The data appears to indicate a more or less constant /O
recovery of Cu when varying the concentration o~ the isopropyl trithio-
carbonate relative to the concentration of the butyl trithiocarbonate but
the % recovery of Fe increases as the isopropyl trithiocarbonate
concentration increases.
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Table Il
Effect of Trithiocarbonate Blends on % Recovery
1100 grams Ore
Run % Recovery
No Collector (0.128 lb/ton) Fe Cu
.
Control:
1 Isopropyl TTCa only 34.72 64.84
2 Isopropyl TTCa only 3~.21 61.16
Average = 32.47 63.0
3 n-Butyl TTCb only 38.71 76.85
4 n-butyl TTCb only 36.85 73.69
Average = 37.78 75.27
InventionC:
55.9% Isopropyl TTC ~ 94.1% n-Butyl TTC 44.94 79.31
65.9% Isopropyl TTC + 94.1% n-Butyl TTC 40.86 78.76
Average = 42.90 79.0
711.1% Isopropyl TTC + 88.9% n-Butyl TTC 48.37 82.63
811.1% Isopropyl TTC + 88.9% n-Butyl TTC ~17.39 77.98
Average = 47.88 80.31
920.0% Isopropyl TTC + 80.0% n-Butyl TTC 49.00 80.25
1020.0% Isopropyl TTC + 80.0% n-Butyl TTC 46.24 75.86
; Average = 47.62 78.01
1125% Isopropyl TTC -~ 75% n-Butyl TTC 53.37 82.94
12%25% Isopropyl TTC + 75% n-Butyl TTC 48.35 77.
Average = 50.85 80.21
aSodium isopropyl trithiocarbonate (1% aqueous solution) prepared from
isopropyl mercaptan, CS2, NaOH, water according to the general
procedure described in Ind. & Eng. Chem. Vol. 42, pg. 5.
Sodium n-butyl trithiocarbonate (1% aqueous solution) prepared from
n~butyl mercaptan, CS2, NaOH, water according to ref. a.
CThe trithiocarbonate blends were prepared in a similar manner as
described by using a corresponding mixture of, for example, 25%
isopropyl mercaptan plus 75% n-butyl mercaptan plus CS2, NaOH in water.
Example III
This example illustrates the effectiveness of combining sodium
n-butyl trithiocarbonate with another type alkyl trithiocarbonate such as
sodium ethyl trithiocarbonate. The general procedure described in
Example I was repeated but using a different type ore (i.e., Pb, Zn,
Fe-containing) and a different collector system (sodium ethyl
'
::,
~2~5~
trithiocarbonate combined with n-butyl trithiocarbonate). These results
listed in Table III show that during the Pb float combining the n-butyl
trithiocarbonate with the ethyl trithiocarbonate (Runs 5, 6) increases
the recovery of Pb as compared to when each collec~or was used separately
S (Runs 1, 2 and 3, 4). The data also shows premixing the ethyl and butyl
trithiocarbonate tRuns 7, 8) is comparable in the % recoveries (Pb, Zn,
Fe) to when the collectors are merely added to the cell together (Runs 5,
6). In addition, the data indicates the butyl trithiocarbonate by itself
gives an undesirable increase in Zn and Fe during the first float (Pb).
Table III
Effect of Trithiocarbonate Blends on % Pb~ Zn Fe Recoveries
(1000 grams Ozark ore, 350 mL water, .75 lbjton ZnS04,
.10 lb/ton NaCN, .03 lb/ton methyl isobutyl carbinol
frother, grind dilute to 35% in flotation cell, add
collector, float 5 mins.)
Run % Recovery
No.Collector (0.09 lb/ton) Pb Zn ~e
Control:
1n-Butyl TTCa only 74.9 53.3 6.32
2n-Butyl TTCa only 84.5 49.7 6.63
Average = 79.7 51.5 6.5
3Ethyl TTCb only 70.4 10.9 3.64
4Ethyl TTCb only 80.8 13.6 1.71
Average = 75.6 12.3 2.7
25 Invention:
550/0 n-Butyl TTC ~ 50% Ethyl TTC 78.625.6 5.97
650% n-Butyl TTC + 50% Ethyl TTC 84.919.3 4.66
Average - 81.8 22.5 5.3
7Premixed Blend of 50% n-Butyl TTC
~ 50~ Ethyl TTC80.0 18.5 4.65
8 Same as 7. 84.5 26.4 5.09
Average = 82.3 22.5 4.9
aSodium n-B~Ityl Trithiocarbonate as a 40% aqueous solution.
bSodium Ethyl Trithiocarbonate as a 40% aqueous solution.
Reasonable variations and modifications which will become
apparent to those skilled in the art can be made in this invention
without departing from the spirit and scope thereof.
