CA1105156A

CA1105156A - Flotation of sulfide minerals

Info

Publication number: CA1105156A
Application number: CA313,124A
Authority: CA
Inventors: William A. Rickelton
Original assignee: American Cyanamid Co
Current assignee: Wyeth Holdings LLC
Priority date: 1978-10-11
Filing date: 1978-10-11
Publication date: 1981-07-14
Also published as: YU238879A; ZM8079A1

Abstract

26, 386 ABSTRACT OF THE DISCLOSURE
N-alkyl, O-alkylthionocarbamates are soluble in con-centrated aqueous solutions of ammonium or alkali metal salts of dialkyldithiophosphinates and the resulting mixture provides improved copper recovery by froth flotation.

Description

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 ~.

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 ::: :: :

~, 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 -'~
,~

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.

: : :
;
: 30 : :
`' ~ :

~ ~ ~r o ~ ~ ~D
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

U~
ul _ ~ o u~ a~
~D, ~O ~ ~ U~
U~
. . ~ .

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

U~ .,1 O O O O
~0 . ~ . .
O ~ ~ ~ O O O o o ~ rl ~ O
0 ~: O~rl q O: U~
~1 ~ c~ a :
~ : :
Q
~0 ~
::
:

~: :::
: ~ : :
;:

:: ::: : :
,: :. :

S~.5~

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.

.

:~
:
~: :: : :
:: :

~::: 25 , , :

: ~ ~ : ::

:::~: ~ ~ :: :::

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 ~ .
` :
~ ,~
:: ,.......... æ
h rl ~m: :
; ~ ~ :
o X
0 t`l : : ' _ 9 _ :
:

`
:: ~

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 .
: ~ .
~: :

: ~30 : ~ :

:
~ ~ :

~, ~

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 ~ :

:
: : ' `

:

~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 -

Claims

26,386 WHAT IS CLAIMED IS:
l. An aqueous solution comprising from about 25 to 75 percent by weight of an alkali metal or ammonium salt of a dialkyldithiophosphinate of the formula:

wherein M is an alkali metal or ammonium ion and R1 and R2 are each alkyl groups of 2 to 12 carbon atom. from about 75 to 25 percent by weight of water, said solution containing dis-solved therein an N-alkyl, 0-alkyl thionocarbamate of the formula:

wherein R3 and R4 are each alkyl groups of 1 to 6 carbon atoms, said thionocarbamate being present in an amount sufficient to provide a weight ratio in the range of from about 95:5 to 50:50 of said dialkyldithiophosphinate solution to said thionocarb-amate, respectively.
2. The solution of Claim 1 wherein said thiono-carbamate is isopropyl methylthionocarbamate.
3. The solution of Claim 1 wherein said thiono-carbamate is isopropyl ethylthionocarbamate.
4. The solution of Claim l wherein said thiono-carbamate is isobutyl methylthionocarbamate.
5. The solution of Claim l wherein said dialkyldi-thiophosphinate is sodium dibutyldithiophosphinate.
6. The solution of Claim l wherein said dialkyldi-thiophosphinate is sodium diisobutyldithiophosphinate.
7. The solution of Claim 1 wherein said thionocar-bamate is isopropyl ethylthionocarbamate and said dialkyldi-thiophosphinate salt is sodlum diisobutyldithiophosphinate.
8. The solution of Claim 1 wherein said thionocar-bamate is isopropyl ethylthionocarbamate and said dialkyldithio-phosphinate salt is ammonium diisobutyldithiophosphinate.
9. In the process of recovering copper values from a copper-bearing ore by froth flotation employing a collector for said copper values, the improvement comprising employing as said collector an aqueous solution of about 25 to 75 per-cent by weight of an alkali metal or ammonium salt of a dialkyl-dithiophosphinate of the formula:

wherein M is an alkali metal or ammonium ion, and R1 and R2 are each alkyl groups of 2 to 12 carbon atoms, from about 75 to 25 percent by weight of water, said solution containing dissolved therein an N-alkyl~ 0-alkyl thionocarbamate of the formula:

wherein R3 and R4 are each alkyl groups of 1 to 6 carbon atoms, said thionocarbamate being present in an amount suficient to provide a weight ratio in the range of from about 95:5 to 50:50 of said dialkyldithiophosphinate solution to said thionocarbam-ate, respectively, said collector being present in an amount of from about 0.001 to 0.1 pounds per ton of ore.
10. The process of Claim 9 wherein said thionocar-bamate is isopropyl methylthionocarbamate.
11. The process of Claim 9 wherein sald thionocarbamate is isopropyl ethylthionocarbamate.
12. The process of Claim 9 wherein said thionocarbamate is isobutyl methylthionocarbamate.
13. The process of Claim 9 wherein said dialkyldithio-phosphinate is sodium dibutyldithiophosphinate.
14. The process of Claim 9 wherein said dialkyldithio-phosphinate is sodium diisobutyldithiophosphinate.
15. The process of Claim 9 wherein said thionocarbamate is isopropyl ethylthionocarbamate and said dialkyldithiophos-phinate salt is sodium diisobutyldithiophosphinate.
16. The process of Claim 9 wherein said thionocar-bamate is isopropyl ethylthionophosphate and said dialkyldi-thiophosphinate salt is ammonium diisobutyldithiophosphate.