Note: Descriptions are shown in the official language in which they were submitted.
26,3~6
This invention relatec, to a novel cornposi-tion of
matter comprising a dialkyldithlophosphinate in combination with
an N-alkyl, O-alkyl thionocarbaMate; with the thionocarbamate
preferably being dissolved in an aqueous solulion of the dialkyl
dithiophosphinate.
Organic compounds are numerous and of highly varied
structure. Such compounds have a variety of uses depending
on their nature and proper-ties. Typically, organic sulfur
compounds are used in the manufacture of rayon and cellophane
as insecticides, as fw~gicides and as flotatiorl agents in the
concentration of minerals. Certain organic sul~ur compounds
are watex soluble while oth~rs are no-t. The lack of water
solubility in many cases interferes with ex-tensive utiliza-
tion of such organic sulfur compounds. In many application,
it is desirable to use mixtures of different types of sulfur
compounds for increased efficiency. However, the incompat-
ibility of different types of sulfur compounds complicates ef-
forts to use mixtures of different types of organic sulfur
compounds. This generally necessitates separate additions of
the diferent types of sulfur compounds to be employed and ex-
tensive processing to effect uniform admixture. In many in-
stances, maximum performance of the mixture is not obtained
because of the incompatibility of the different sulfur
compounds.
Alkali metal or ammonium salts of dialkyl dithio~
phosphinates are water soluble organic sulfur compounds that
have been used as flotation ageslts in the concentration of
minerals. N-alkyl, O-a1kylthionocarbamates are water in-
soluble olls that also have typical uses of organic sulfur
compounds/ such as flotation agents in the concentration of
- 1 -
~.
minerals. The disslmilar solubi.lity characteristics of
these difEerent compound types clo not suggest that these com~
pounds could be employed as a si.ngle composition.
In accordance with the present invention, there is
provided a stable a~ueous solution comprising from about 25 to
75 weight percent of an alkali metal or ammonium salt of a di-
alkyldithiophosphinate and, corl-espondingly, from about 75 to
25 weight percent of wa-ter, sa:id solution containing dissolved
therein sufficient of an N-alkyl, O-alkyl thionocarbamate to
provide a volume ratio in the range of from about 95:5 to
50:50 of said di.alkyldithiophosphil1ate sal-t solution to said
thionocarbamate, respectively.
The solubility of N-alkyl, O-alkyl thionocarbamates
in aqueous solutions of alkali meta:L or ammonium salts of di-
alkyldithiophosphinates is h.igh:Ly unexpected :Eor numerous
reasons. The N-alkyl, O-alkyl 1:hionocarbamate~s are insoluble
in aqueous solutions of alkali metal alkyl xanthates. The thio-
phosphinates are immiscible in allyl amyl xanthate, a water in-
soluble oil similar in nature and application to the thiono-
earbamates. Toluene, an organic so].vent, was found to be im-
miscible with the aqueous dithiophosphinates in proportions
at whieh the thionocarbamates a:re miscible. The range of pro-
portions at which the various thionocarbamates are miscible
with the aqueous dithiophosphinates varies with the individual
compounds of both types.
: In accordance with the process aspect of the pre-
sent invention, there is provided an improvement in the pro-
eess of recovering eopper values from a coppe:r-bearing ore by
froth flotation which comprises using as collector for said
30~ eopper va~ues an aqueous solution eomprising from about 25 to
: ~:
~ 2 -
: ~
75 weight percent o~ an alkali metal or ammon:ium salt of a
diallcyldithiophosphinate and, correspolldingly, from about 75
to 25 weight percent of waterl said solution containing dis-
solved therein sufficient of an N-alkyl O-alk~l thionocarba-
mate to provide a volume ratio in the range O:e about 95:5 to
60:40 of said dialkyldithiophosphinate salt solution to said
thionocarbamate, respectively, saicl collector bein-J used at
from about 0.001 to about 0.1 pound3 per ton of ore.
The dialkyldithiophosphinates useful in the present
invention have the general formula:
Rl~ 11
~ P -S -M
wherein M is an alkali metal or ammonium ion and Rl and R2 are
lS individually selected from alkyl groups of 2 to 12 carbon
atoms having straight or branched chains. Typical compounds
include sodium diethyldithiophosphinate, sodium diisopropyl-
dithiophosphinate, sodium c~iisobutyldithiophosphinate, sodium
diisoamyldithiophosphinate, and the corresponding compounds as
the ammonlum or potasslum salts. All of the dithiophosphinates
contemplated for use in the present invention are water soluble.
The thionocarbamates useful in the present invent-
ion have the structure:
S
25~ ~ R3 _NH ~C OR4
wherein R3 and R4 ara individually selected from alkyl groups
of about 1 to 6 carbon atoms having straight or branched chains.
Typical compounds include isopropyl methylthionocarbamake, iso-
propyl ethylthlonocarbamate, isobutyl methy}thionocarbamate and
the like. The first alkyl radical named in the nomenclature
::: :: :
- 3 -
~,
is attached to the oxygen atom. Thus, the alkylthionocarbamic
acid is identified and the ester thereof is specified by the
first alkyl rad.ica~. named. The comyo~lncls are sometimes called
thioncarbamates but for euphony the thionocarbamate clesigna-
tion is preferred. All of the thionocarbamates contemplated
for use in the invention are water insoluble oils.
In preparing the compositions o~ the present inven-t-
ion, an aqueous so].ution of the dialkyldithiophosphinate salt is
prepared. Generally such salt will be prepared as about a 35
to 70 weight percent aqueous solution, depending upon the sol
ubility limit of the particular dialkyldithiophosphinate salt
employed. Solubility of the thionocarbamate is predicated on
the dialkyldithiophosphinate salt solution being concentrated,
generally at least about 25 weight percent.
In preparing the compositions of the invention, the
oily, water insoluble, thionocarbamate is mixed with the con- . .
centrated aqueous dialkyldithiophosphinate salt until solution
occurs. The amount of thionocarbamate used i.n the mixture in
preparing the composition will generally be i.n a range such as
to provide a volume ratio of from about 95:5 to 60:40 of said
dialkyldithiophosphinate salt solution to sai.d thionocarbamate,
respectively. The individual t.hionocarbamates vary in solubil-
ity in aqueous sol~utions of particular dialkyldithiophosphin-
:~: ate salts and, accordingly, varying maximum contents of thio-
nocarbamates in the composition wil.l arise.
It is generally preferred to prepare the solutions
: at or near the levels of maximum solubility of the dialkyl-
dithiophosphlnate~salt and to add thereto the requisite weight
ratio of thionocarbamate whi.ch is~desirable i.n the specific
: 30 appl.ication in which use is co~templated. Thus, the high con-
,
: - 4 -
5~
centration of diallcyldithiophosphinate salt minimizes shippi.ng
costs and the desired level of thionocarbamat:e minimiæes hand
lin~.
The compositions of t.he present in~en-tion eliminate
the need for separate additions of the two ingredients when
co-use thereof is desirable, thus reducing the number of pro-
cessing steps that would otherwise be required Eor co-use.
The compositions also provide t.he thionocarbamates in desirable
form for addition, in aqueous solution Porm, a form previously
lD not available. The aqueous solution .Eorm i.s desirable in many
applications where it is compat.ible in the preocess being per-
formed and thus eliminates the problems associated with uni-
formly dispersing the normal oily, water insoluble, thionocar-
bamates. Furthermore, the compositions o the invention pro-
vide improved performance over the separate use of either of
the specific ingredients alone. Thus, not or,ly do the composit~
ions of the present invention eliminate processing steps and
handling difficulties normally associ.ated wit.h uses of thiono-
carbamates, but also may provide improved performance as com-
pared to the individual use of the materials.
A particular application in which the solutions of
the present inventi.on show advantage is that of collector in
concentrating valuable constituents Erom ores by flotation.
The mixed solution of thionocarbamate and dialkyldithiophos-
phinate provides advantages in the flotation of metallic sul-
: fides such as those o~copper, zinc, lead, platinum, nickel
and molybdenum ores. The advantages include reduction in
: ~ processing steps~by use of the combined solution and may pro-
vide lncreased recovery of desired metal values while main-
taining a high grade concentrate.
::
~ ~ - 5 -
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,~
The collector is used in an amount which will provide
best recovery of metal while mairltaining a high grade of metal.
Generally, this amount will vary Erom about 0.001 to about 0.1
pound of collector per ton of ore, preferably about 0.005 to
about 0.05 pound per ton. Usage will vary depending upon the
particular ore processed, the composition of the collector
solution, and the processing ecluipmerlt employed. Optimum usaye
can be readily determined by trial.
The invention is i.llustra-ted by the examples which
follow wherein all parts and percentayes are by weigh-t unless
otherwise specified.
EXAMPLES_l ~ 5
A crushed and ground ore sample containing copper,
primarily as chalcopyrite, was submitted to a conventional
laboratory flotation procedure using various collectors and
: collector combïnat.ions at varyi.ng usage levels. A flotation
time of seven and one half minutes was required to obtain a
: copper concentrate. Frother uC.age (methyl isobutyl carbinol)
was 0.1 lb. per ton of ore and the flotation pH was 10.5. The
collectors employed, the usage levels run specified as pounds
acti.ve ingredient/ton of ore and the result obtained are given
:
in Table I below. When usecl in combination, the th.ionocarbamate
` was dissolved in an aqueous so].ution of the clialkyldithiophosphin-
:~ ~ ate with moderate stirring at room temperature prior to addi-
tion to the flotation cell.
: : :
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: 30
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c~ o
o r~ o o r~
~;
u~ ~ ~ co r- ~
-~1 O O O c~ O
E~ o o o o o
.
V N CO 1` 1` cn
~:: a~ o c~
O
~r ~ ~`I t`l ~`J
o'lP
V
0
U~
ul _ ~ o u~ a~
~D, ~O ~ ~ U~
U~
. . ~ .
0 O O O O O
m
Lr~
.
~,
O
~1 ~ Ql t~
O O O O O O O
1:'1 ~4 ~
o ~ o~ ~ rl
F~ U~ O
E~ 1-l ~1 H
O
U~
P; O
0
U~ .,1
O O O O
~0 . ~ . .
O ~ ~ ~ O O O o o
~ rl ~ O
0 ~: O~rl
q O: U~
~1
~ c~ a
:
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Q
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::
:
~: :::
: ~ : :
;:
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,: :. :
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C M ARATIV~ EXAMPL:ES A AND B
The procedure of Examples 1 - 5 was repeated with
two commercially available collectors using the same ore. The
results are shown in Table II.
.
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,
, :
: ~ ~ : ::
:::~: ~ ~ :: :::
1 .5 ~
h
O
c~ o a~
dP ~ ~ ~X7
u~ oo ~r
~1 ~ ~P
. O O
E~ o o
~,1 ~ ,, a
c~
H g~ td ~ O
H ~ H ~ ; ~ ~ a ,1
o a ~:s
O
~ o ~o I
E~ H ~
:~ ~' ~
: ~ O O ~ ~
~ O O
O )-1
~0
: a
O
:~ ~ m
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:: ,.......... æ
h rl
~m: :
; ~ ~ :
o X
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EXA~IPI,ES 6 - 9
The procedure of Examples 1--5 was repeated using an
ore containing copper and zine; as chalcopyrite and sphalerite
respectively. The collectors were tested in the copper flota-
tion stage. A frother (methyl isobutyl carbinol) was used at
the rate of 0.08 lb./ton of ore, a collection time of nine min-
utes was used and the flota-tion pH was 10.5~ The results are
given in Table III below.
:25
.
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~: :
: ~30
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:
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~, ~
h
~ ~ I~ r~
o~o o ~r Ir) ~r
O ot~ cl) c~
u~ ~ cs~ r~ o
_I r u~ ~D CO
~rl H
E~ o c) o o
~ T~ N H 1-- tO
C.) O ~r o; cs~ co
dP ~ r~ ~
U~
~ _
~ ~)
tn ,~
d c~ c~
~, C~ r-
~a ~ r1 H H
. ~
C~
H ¦ Pl r-l h ~ ~1 r-l
~ol o o~ o '~
O
:n ~
r-l rl ~ Ul Ll l
~`1 ~1 ~r
~0 O O O
Ul r~ ,q O O C; O O
~ r~
:
r
co cr~ :
X
~1 ~ :
:
: : '
1 1 --
`
:
~5~LS~
EX~MP~E~,S ].0-13
The procedure of ~xanlples 6 - 9 is repeated on the
same ore but using sodium di.isobu-tyldithiophosphinate and iso-
propyl methylthionocarbamate as the collectors. Similar super-
ior results for the c~ombinatiorl are found.
:
:
~ : - 12 -
