CA1263662A - O,o'-, o,s'-or s,s'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamothioates) and s,s'- dithiodialkylene-bis(mono- or dihydrocarbyl carbamodithioates) useful as froth flotation collectors - Google Patents
O,o'-, o,s'-or s,s'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamothioates) and s,s'- dithiodialkylene-bis(mono- or dihydrocarbyl carbamodithioates) useful as froth flotation collectorsInfo
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- CA1263662A CA1263662A CA000507447A CA507447A CA1263662A CA 1263662 A CA1263662 A CA 1263662A CA 000507447 A CA000507447 A CA 000507447A CA 507447 A CA507447 A CA 507447A CA 1263662 A CA1263662 A CA 1263662A
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- dihydrocarbyl
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Abstract
ABSTRACT
The invention concerns novel O,O'-, O,S'- or S,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamo-thioates) and S,S'-dithiodialkylene-bis(mono- or dihydro carbyl carbamodithioate). The novel compounds are useful as collectors in the froth flotation of sulfide mineral ores.
The invention concerns novel O,O'-, O,S'- or S,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamo-thioates) and S,S'-dithiodialkylene-bis(mono- or dihydro carbyl carbamodithioate). The novel compounds are useful as collectors in the froth flotation of sulfide mineral ores.
Description
`` NOVEL O,O'-, O,S'- OR
S,S'-DITHIODIALKYLENE-BIS(MONO- OR
DIHYDROCARBYL CARBAMOTHIOATES) AND
S,S'-DITMIODIALKYLENE-BIS(MONO-OR DIHYDROCARBYL CARBAMODITHIOATES) USEFUL AS FROTH FLOTATION COLLECTORS
This invention concerns novel compounds, specifically O,O'-, O,S'- or S,S'-dithiodialkylene-bis~
(mono- or dihydrocarbyl carbamothioates) and S,S'-dithio-dialkylene-~is(mono- or dihydrocarbyl carbamodithioates) and their use as collectors in the recovery of sulfide ores by froth flotation.
Flotation is a process of treating a mixture of finely divided mineral solids, e.g., a pulverulent ore, suspended in a liquid whereby a portion of such solids is ` ld separated from other finely divided mineral sollds, e.g., clays and the like materials present in the ore, by intro-ducing a gas into the liquid (or providing a gas ln situ) to produce a frothy mass containing certain of the solids on the top of the liquid, and leaving suspended (unfrothed) other solid components of the ore. Flotation is based on 31,361-F -1-
S,S'-DITHIODIALKYLENE-BIS(MONO- OR
DIHYDROCARBYL CARBAMOTHIOATES) AND
S,S'-DITMIODIALKYLENE-BIS(MONO-OR DIHYDROCARBYL CARBAMODITHIOATES) USEFUL AS FROTH FLOTATION COLLECTORS
This invention concerns novel compounds, specifically O,O'-, O,S'- or S,S'-dithiodialkylene-bis~
(mono- or dihydrocarbyl carbamothioates) and S,S'-dithio-dialkylene-~is(mono- or dihydrocarbyl carbamodithioates) and their use as collectors in the recovery of sulfide ores by froth flotation.
Flotation is a process of treating a mixture of finely divided mineral solids, e.g., a pulverulent ore, suspended in a liquid whereby a portion of such solids is ` ld separated from other finely divided mineral sollds, e.g., clays and the like materials present in the ore, by intro-ducing a gas into the liquid (or providing a gas ln situ) to produce a frothy mass containing certain of the solids on the top of the liquid, and leaving suspended (unfrothed) other solid components of the ore. Flotation is based on 31,361-F -1-
-2~ 3~ 6 Z
the principle that introducing a gas into a liquid containing solid particles of different materials suspended thereln causes adherence of some gas to certain suspended solids and not to o-thers and makes S the particles having the gas thus adhered thereto lighter than the li~uid. Accordingly, these particles rise to the top of the liquid to form a froth.
An understanding of the phenomena whic~ makes flotation a particularly valuable industrial operation is not essential to the practice of the present invention.
Such phenomena appear, however, to be largely associated with selective affinity of the surface of particulated solids, suspended in a liquid containing entrapped gas, for the li~uid on one hand and the gas on the other.
.
The flotation principle is applied in.a number of mineral separation processes among which is the selective separation of such minerals as sul~ide copper minerals, sulfide zinc minerals, sulfide molybdenum minerals and others from sulfide iron minerals.
..
`~ 20 Various flotation agents have been admixed with the suspension to improve the frothing process. Such ~; added agents are classed according to the function to be performed: collectors, e.g., high carbon chain compounds ~ such as collectors for sulfide minerals including ; 25 xanthates, thionocarbamate, dithiophosphates, mercaptans, and the like; frothers which impart the property of forming a stable froth, e.g., natural oils such as pine oil and eucalyptus oil; modifiers such as activators to , induce flotation in the presence of a collector, e.g., copper sulfate; depressants, e.g., sodium cyanide, which tend to prevent a collector from functioning as such on a certain mineral which it is desired to retain in the :. .
~ 31,361-F -2-., ;
.
.
:
., i;
the principle that introducing a gas into a liquid containing solid particles of different materials suspended thereln causes adherence of some gas to certain suspended solids and not to o-thers and makes S the particles having the gas thus adhered thereto lighter than the li~uid. Accordingly, these particles rise to the top of the liquid to form a froth.
An understanding of the phenomena whic~ makes flotation a particularly valuable industrial operation is not essential to the practice of the present invention.
Such phenomena appear, however, to be largely associated with selective affinity of the surface of particulated solids, suspended in a liquid containing entrapped gas, for the li~uid on one hand and the gas on the other.
.
The flotation principle is applied in.a number of mineral separation processes among which is the selective separation of such minerals as sul~ide copper minerals, sulfide zinc minerals, sulfide molybdenum minerals and others from sulfide iron minerals.
..
`~ 20 Various flotation agents have been admixed with the suspension to improve the frothing process. Such ~; added agents are classed according to the function to be performed: collectors, e.g., high carbon chain compounds ~ such as collectors for sulfide minerals including ; 25 xanthates, thionocarbamate, dithiophosphates, mercaptans, and the like; frothers which impart the property of forming a stable froth, e.g., natural oils such as pine oil and eucalyptus oil; modifiers such as activators to , induce flotation in the presence of a collector, e.g., copper sulfate; depressants, e.g., sodium cyanide, which tend to prevent a collector from functioning as such on a certain mineral which it is desired to retain in the :. .
~ 31,361-F -2-., ;
.
.
:
., i;
-3~
liquid, and thereby discourage a substance ~rom being carried up and forming a par-t of the froth; pH regulators to produce optimum metallurgical results, e.g., lime, soda ash and the like.
These foregoing flotation additaments are selected for use according to th-e nature of the ore, the mineral sought to be recovered, and the other additaments which are to be used in combinat~on theréwith.
Xanthates and dithiophosphates are relatively inexpensive collectors but have a comparatively low activity as collectors, thus requiring larger concen-trations than some other collectors to get satisfactory activity. The thionocarbamates have good activity as collectors but are relatively expensive to produce.
Further, in the preparation of thionocarbamates, salt and odorous by-products are prepared. These by-products must be removed from the thionocarbamates.
Although the following patents disclose compounds similar to the compounds now claimed, the patents concern other utilities and are structurally distinguished.
U. S. Patent 3,579,516 discloses compounds of the formula .
Rl S S R
" "
R2 N-c-s-cH2-sx-cH2-s-c- N~R4 wherein R1 and R3 are alkyl or aryl; R2 and R~ are alkyl;
and R1 and R2 may form a ring, and R3 and R~ may form a 31,361-F . -3-
liquid, and thereby discourage a substance ~rom being carried up and forming a par-t of the froth; pH regulators to produce optimum metallurgical results, e.g., lime, soda ash and the like.
These foregoing flotation additaments are selected for use according to th-e nature of the ore, the mineral sought to be recovered, and the other additaments which are to be used in combinat~on theréwith.
Xanthates and dithiophosphates are relatively inexpensive collectors but have a comparatively low activity as collectors, thus requiring larger concen-trations than some other collectors to get satisfactory activity. The thionocarbamates have good activity as collectors but are relatively expensive to produce.
Further, in the preparation of thionocarbamates, salt and odorous by-products are prepared. These by-products must be removed from the thionocarbamates.
Although the following patents disclose compounds similar to the compounds now claimed, the patents concern other utilities and are structurally distinguished.
U. S. Patent 3,579,516 discloses compounds of the formula .
Rl S S R
" "
R2 N-c-s-cH2-sx-cH2-s-c- N~R4 wherein R1 and R3 are alkyl or aryl; R2 and R~ are alkyl;
and R1 and R2 may form a ring, and R3 and R~ may form a 31,361-F . -3-
-4~
ring; and X is an integer of from 2 to 6. These compounds are useful as vulcanizing agents.
U. S. Patent 3,876,550 discloses lubrican-t compositions having an aliphatic hydrocarbon substituted succinic acid or derivatives thereof and an alkylene ~ithiocarbamate which corresponds to the formula S S
RlR2N-C-S-X-S -C-NR3R4 wherein: R1, R2, R3 and R4 are a hydrogen or alkyl; or R
and R2 may be taken together to form a heterocyclic ring;
or R3 and ~4 may be taken together to form a heterocyclic ring; and X is Cl 8 alkylene radical.
. There is needed a froth flotation collector s, 15 which is relatively inexpensive to prepare which has a high activity as a collector for sulfide ores. There is furthex needed a collector which can be prepared by a process that does not produce salt or odorous by-products.
i The invention concerns novel 0,0'-, 0,S'- or . 20 S,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamo-thioates) and S,S'-dithiodialkylene-bis(mono- or dihydro-carbyl carbamodithioates).
Another aspect of this invention is a-process for the preparation of 0,0'-, 0,S'- or S,S'-dithiodi-alkylene-bis(mono- or dihydrocarbyl carbamothioates) and , S,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamo-- thioates) which comprises .
31,361-F -4-.
: ~s ~, . .
.. .
.
:~
.~!' ,:, ., ' . ~
~5- ~r~,6~
(1) contacting a 1,3-oxathiolane-2-thione or a 1,3-dithiolone-2-thione with a primary or secondary amine in a nonpolar solvent under conditions such that an S- or 0-(2~mercap-toalkyl~mono- or dihydrocarbyl carbamothioate or an S-(2-mercaptoalkyl)mono- or dihydrocarbyl carbamodithioate is formed; and - - (2) addiny to the above reaction solution an oxidant which is capable of oxidizing the mercapto - moiety under cond.itions such that 0,0'-, 0,S'- or S,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamothioate) or S,S'-dithiodialkylene-bis(mono-or dihydrocarbyl carbamodithioate) is prepared.
A further aspect of this invention is a process of concentrating sulfide ores by flotation, which comprises subjecting the sulfide ore in the form of a pulp, to a flotation process in the presence of a flotating amount of a flotation collector for the sulfide comprising a 0,0'-, 0,S'- or S,S'-dithiodialkylene bis(mono- or dihydrocarbyl carbamothioate) (hereinafter disulfide carbamothioates) or S,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamo-dithioate) (hereinafter disulfide carbamodithioates), or mixtures thereof.
The disulfide carbamothioates and disulfide carbamodithioates of this invention have good activity as collectors, and better activity than the xanthates and - dithiophosphates, Further, the compounds of thi~ invention are less expensive to prepare than the thionocarbamates.
Also, the process for the preparation of the compounds of this invention does not result in the preparation of salt or odorous by-products.
: `
~;
31,361-F -5~
.
~ 2 The invention includes O,O'-, O,S'- or S,S'--dithiodialkylene-bis(mono- or dihydrocarbyl carbamothio ates) and S,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamodithloates) which correspond to the formula Rl X R3 R3 R3 R3 X R1 ~ 11 ~ I I 11 /
~ NCY-C -C-SS-C C-YCN' R2 R4 R~ R4 R4 `~R2 ~. . .
wherein R1 is separately in each occurrence hydrogen or C1 ~0 hydrocarbyl;
R is separately in each occurrence Cl 20 hydrocarbyl;
R3 is separately in each occurrence hydrogen or C1_~0 hydrocarbyl;
R is separately in each occurrence hydrogen or Cl 20 hydrocarbyli X is separately in each occurrence O or S;
and Y is separately in each occurrence O or S;
with the proviso that both X and Y cannot be oxygen and with the further proviso that at least one R3 and one R4 on the same carbon atom on each alkylene moiety must be hy~drogen.
A preferred class of compounds of the above formula is the O,O'-S,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamothioates), such as the O,O'-disulfide dialkylene-bis(mono- or dihydrocarbyl carbamothioates) of 31,361 F -6-) -7- .~
this invention which include those corresponding to the formula R1 S R3 R3 R3 R3 s R
~ "
~NCO-C- C-SS-C--C-OCN~
R R4 R4 R4 R4 \ R2 wherein R1, R2, R3 and R4 are as defined above.
The 0,S'-disulfide dialkylene-bis(mono- or dihydrocarbyl carbamothioates) of this invention corre-spond to the formula " , , , . Il `NCS-C--C-SS-C -C-OCN~
R2 / R4 R4 R4 R4 \ R2 wherein R1, R2, R3 and R4 are as defined above.
The S,S'-disulfide dialkylene-bis(mono- or dihydrocarbyl carbamothioates) of this invention corre-spond to the formula Rl R3 R3 R3 R3 R
\ NCS-C-~C-SS-C - C-SCN /
` 25 R2 R4 R4 R4 R4 \ R2 wherein R1, R2, R3 and R4 are as defined above.
The S,S'-disulfide dialkylene-bis(mono- or dihydrocarbyl carbamodithioates) of this invention include those corresponding to the formula i~ .
~ 31,361-F -7-`
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.
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''~' ~., `:
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Rl S R3 R3 R3 R3 S R
~ " , , I 1 11 ~
"NCS-C--C-SS-C--C-SCN~
R2 R4 R4 R4 R~L ~R2 wherein R1, R2, R3 and R4 are as defined above.
Rl is preferably hydrogen or C1_20 alkyl and most preferably hydrogen. R is preferably C1 20 alkyl or phenyl; more preferably C2 10 alkyl, and most prefer-ably C2 6 alkyl. R3 is preferably hydrogen or C1 20 alkyl, more preferably hydrogen or C1 4 alkyl, and most preferably hydrogen. R4 is preferably C1 20 alkyl and most preferably C1 4 alkyl.
In one preferred embodiment, the nitrogen atom on the carbamate moiety is substituted with one hydro-carbyl group. In another preferred embodiment, the alkylene moiety has only one substituent.
C1 20 hydrocarbyl means herein an organic radical containing between one and twenty carbon atoms to which are bonded hydrogen atoms. Included are the following groups: Cl_20 alkyl~ C1-20 alkenyl~ C1-20 alkynyl~ C3_20 cycloalkyl, C3_20 cycloalkenyl~ C6 20 aryl, C7_20 alkaryl or C7 20 aralkyl.
.
The term aryl Eefers herein to biaryl, phenyl, naphthyl, phenanthranyl and anthranyl. Alkaryl refers herein to an alkyl-, alkenyl- or alkynyl-substituted aryl substituent wherein aryl is as defined hereinbefore.
Aralkyl means herein an alkyl, alkenyl or alkynyl substit-uent substituted with an aryl group, wherein aryl is as defined hereinbefore.
i 31, 361~F -8-_g~ $ ~
C3 20 cycloalkyl refers to an alkyl group containing one, two, three or more cyclic rings. C3 20 cycloalkenyl refers to mono-, di- and polycycllc groups containing one or more double bonds. C3 20 cycloalkenyl also refers to the cyclo~alkenyl groups wherein two or more double bonds are present.
The O,O'-, O,S'- or S,S'-dithiodialk~lene-bis-(mono- or dihydrocarbyl carbamothioates) are prepared by reacting a primary or secondary amine with a 1,3~oxa-1~ thiolane-2-thione in a suitable solvent to prepare a S-(2-mercaptoalkyl)mono- or dihydrocarbyl carbamothioate (hereinafter S-mercapto carbamothioate), 0-(2-mercapto-alkyl)mono- or dihydrocarbyl carbamothioate (hereinafter O-mercapto carbamothioate),- or mixtures thereo~. In order to get high yields of the 0-(2-mercaptoalkyl)mono- or di~ydrocarbyl carbamothioate, a nonpolar solvent should be used. The 0-(2-mercaptoalkyl) carbamothioate, the S-(2--mercaptoalkyl) carbamothioate, or mixtures thereof are then contacted with an oxidation agent to prepare the 2~ ~,O'-, O,S'- or S,S'-dithiodialkylene-bis(mono- or dihydro-carbyl carbamothioate) or~mixtures thereof.
The dithiodialkylene~bis(mono- or dihydrocarbyl carbamodithioates) are prepared by contac-ting a 1,3--dithiolane-2-thione with a primary or secondary amine to ~S prepare a (2-mercaptoalkyl)mono- or dihydrocarbyl carbamo-dithioate ~hereinafter referred to as mercapto carbamodi-thioate). The mercapto carbamodithioate is then contacted with an oxidation agent to prepare the dithiodialkylene--bis(mono- or dihydrocarbyl carbamodithioates).
Amines useful in this process include those which correspond to the formula HNRlR2 wherein R1 and R2 are as defined hereinbefore.
31,361-F -g-t,~ J
Specific illustra-tive examples of the amines contemplated herein are shown by the following:
(1) monoalkylamines including, for example, methyl~mine, ethylamine, propylamine, isopropylamine, n-butylamine, sec-butylamine, isobutylamine, pentyl-~ amines, hexylamines, cyclohexylamines, heptylamines, octylamines, dodecylamines, octadecylamines, eicosyl-` amines, triacontanylamines, benzylamine, chloro-~enzylamine, nitrobenzylamine, 2-ethoxyethylamine, 4-carbomethoxyhexylamine;
(2~ dialkylamines including, for example, dimethylamine, diethylamine, di-n-propylamine, diisopropylamine, di-,n-butylamine, di-sec-butylamine, diisobutylamine, di-tert-butylamine, dipentylamines, dihexylamines, dioctylamines, ditriacontanylamine, N-methylethylamine, N-methylpropylamine, N-methyl-octadecylamine, N-ethylhexylamine, N-ethyldodecyl-amine, N-propyldodecylamine;
(3) heterocyclic aliphatic secondary amines including, ~or example, piperazine, pyrrole, imidazoline, pyrazole, piperazine;
(4) arylamines including, for example, aniline, toluidine, anisidine, nitroaniline, bromoaniline, xylidines, 4-ethylaniline, naphthylamine;
ring; and X is an integer of from 2 to 6. These compounds are useful as vulcanizing agents.
U. S. Patent 3,876,550 discloses lubrican-t compositions having an aliphatic hydrocarbon substituted succinic acid or derivatives thereof and an alkylene ~ithiocarbamate which corresponds to the formula S S
RlR2N-C-S-X-S -C-NR3R4 wherein: R1, R2, R3 and R4 are a hydrogen or alkyl; or R
and R2 may be taken together to form a heterocyclic ring;
or R3 and ~4 may be taken together to form a heterocyclic ring; and X is Cl 8 alkylene radical.
. There is needed a froth flotation collector s, 15 which is relatively inexpensive to prepare which has a high activity as a collector for sulfide ores. There is furthex needed a collector which can be prepared by a process that does not produce salt or odorous by-products.
i The invention concerns novel 0,0'-, 0,S'- or . 20 S,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamo-thioates) and S,S'-dithiodialkylene-bis(mono- or dihydro-carbyl carbamodithioates).
Another aspect of this invention is a-process for the preparation of 0,0'-, 0,S'- or S,S'-dithiodi-alkylene-bis(mono- or dihydrocarbyl carbamothioates) and , S,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamo-- thioates) which comprises .
31,361-F -4-.
: ~s ~, . .
.. .
.
:~
.~!' ,:, ., ' . ~
~5- ~r~,6~
(1) contacting a 1,3-oxathiolane-2-thione or a 1,3-dithiolone-2-thione with a primary or secondary amine in a nonpolar solvent under conditions such that an S- or 0-(2~mercap-toalkyl~mono- or dihydrocarbyl carbamothioate or an S-(2-mercaptoalkyl)mono- or dihydrocarbyl carbamodithioate is formed; and - - (2) addiny to the above reaction solution an oxidant which is capable of oxidizing the mercapto - moiety under cond.itions such that 0,0'-, 0,S'- or S,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamothioate) or S,S'-dithiodialkylene-bis(mono-or dihydrocarbyl carbamodithioate) is prepared.
A further aspect of this invention is a process of concentrating sulfide ores by flotation, which comprises subjecting the sulfide ore in the form of a pulp, to a flotation process in the presence of a flotating amount of a flotation collector for the sulfide comprising a 0,0'-, 0,S'- or S,S'-dithiodialkylene bis(mono- or dihydrocarbyl carbamothioate) (hereinafter disulfide carbamothioates) or S,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamo-dithioate) (hereinafter disulfide carbamodithioates), or mixtures thereof.
The disulfide carbamothioates and disulfide carbamodithioates of this invention have good activity as collectors, and better activity than the xanthates and - dithiophosphates, Further, the compounds of thi~ invention are less expensive to prepare than the thionocarbamates.
Also, the process for the preparation of the compounds of this invention does not result in the preparation of salt or odorous by-products.
: `
~;
31,361-F -5~
.
~ 2 The invention includes O,O'-, O,S'- or S,S'--dithiodialkylene-bis(mono- or dihydrocarbyl carbamothio ates) and S,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamodithloates) which correspond to the formula Rl X R3 R3 R3 R3 X R1 ~ 11 ~ I I 11 /
~ NCY-C -C-SS-C C-YCN' R2 R4 R~ R4 R4 `~R2 ~. . .
wherein R1 is separately in each occurrence hydrogen or C1 ~0 hydrocarbyl;
R is separately in each occurrence Cl 20 hydrocarbyl;
R3 is separately in each occurrence hydrogen or C1_~0 hydrocarbyl;
R is separately in each occurrence hydrogen or Cl 20 hydrocarbyli X is separately in each occurrence O or S;
and Y is separately in each occurrence O or S;
with the proviso that both X and Y cannot be oxygen and with the further proviso that at least one R3 and one R4 on the same carbon atom on each alkylene moiety must be hy~drogen.
A preferred class of compounds of the above formula is the O,O'-S,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamothioates), such as the O,O'-disulfide dialkylene-bis(mono- or dihydrocarbyl carbamothioates) of 31,361 F -6-) -7- .~
this invention which include those corresponding to the formula R1 S R3 R3 R3 R3 s R
~ "
~NCO-C- C-SS-C--C-OCN~
R R4 R4 R4 R4 \ R2 wherein R1, R2, R3 and R4 are as defined above.
The 0,S'-disulfide dialkylene-bis(mono- or dihydrocarbyl carbamothioates) of this invention corre-spond to the formula " , , , . Il `NCS-C--C-SS-C -C-OCN~
R2 / R4 R4 R4 R4 \ R2 wherein R1, R2, R3 and R4 are as defined above.
The S,S'-disulfide dialkylene-bis(mono- or dihydrocarbyl carbamothioates) of this invention corre-spond to the formula Rl R3 R3 R3 R3 R
\ NCS-C-~C-SS-C - C-SCN /
` 25 R2 R4 R4 R4 R4 \ R2 wherein R1, R2, R3 and R4 are as defined above.
The S,S'-disulfide dialkylene-bis(mono- or dihydrocarbyl carbamodithioates) of this invention include those corresponding to the formula i~ .
~ 31,361-F -7-`
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Rl S R3 R3 R3 R3 S R
~ " , , I 1 11 ~
"NCS-C--C-SS-C--C-SCN~
R2 R4 R4 R4 R~L ~R2 wherein R1, R2, R3 and R4 are as defined above.
Rl is preferably hydrogen or C1_20 alkyl and most preferably hydrogen. R is preferably C1 20 alkyl or phenyl; more preferably C2 10 alkyl, and most prefer-ably C2 6 alkyl. R3 is preferably hydrogen or C1 20 alkyl, more preferably hydrogen or C1 4 alkyl, and most preferably hydrogen. R4 is preferably C1 20 alkyl and most preferably C1 4 alkyl.
In one preferred embodiment, the nitrogen atom on the carbamate moiety is substituted with one hydro-carbyl group. In another preferred embodiment, the alkylene moiety has only one substituent.
C1 20 hydrocarbyl means herein an organic radical containing between one and twenty carbon atoms to which are bonded hydrogen atoms. Included are the following groups: Cl_20 alkyl~ C1-20 alkenyl~ C1-20 alkynyl~ C3_20 cycloalkyl, C3_20 cycloalkenyl~ C6 20 aryl, C7_20 alkaryl or C7 20 aralkyl.
.
The term aryl Eefers herein to biaryl, phenyl, naphthyl, phenanthranyl and anthranyl. Alkaryl refers herein to an alkyl-, alkenyl- or alkynyl-substituted aryl substituent wherein aryl is as defined hereinbefore.
Aralkyl means herein an alkyl, alkenyl or alkynyl substit-uent substituted with an aryl group, wherein aryl is as defined hereinbefore.
i 31, 361~F -8-_g~ $ ~
C3 20 cycloalkyl refers to an alkyl group containing one, two, three or more cyclic rings. C3 20 cycloalkenyl refers to mono-, di- and polycycllc groups containing one or more double bonds. C3 20 cycloalkenyl also refers to the cyclo~alkenyl groups wherein two or more double bonds are present.
The O,O'-, O,S'- or S,S'-dithiodialk~lene-bis-(mono- or dihydrocarbyl carbamothioates) are prepared by reacting a primary or secondary amine with a 1,3~oxa-1~ thiolane-2-thione in a suitable solvent to prepare a S-(2-mercaptoalkyl)mono- or dihydrocarbyl carbamothioate (hereinafter S-mercapto carbamothioate), 0-(2-mercapto-alkyl)mono- or dihydrocarbyl carbamothioate (hereinafter O-mercapto carbamothioate),- or mixtures thereo~. In order to get high yields of the 0-(2-mercaptoalkyl)mono- or di~ydrocarbyl carbamothioate, a nonpolar solvent should be used. The 0-(2-mercaptoalkyl) carbamothioate, the S-(2--mercaptoalkyl) carbamothioate, or mixtures thereof are then contacted with an oxidation agent to prepare the 2~ ~,O'-, O,S'- or S,S'-dithiodialkylene-bis(mono- or dihydro-carbyl carbamothioate) or~mixtures thereof.
The dithiodialkylene~bis(mono- or dihydrocarbyl carbamodithioates) are prepared by contac-ting a 1,3--dithiolane-2-thione with a primary or secondary amine to ~S prepare a (2-mercaptoalkyl)mono- or dihydrocarbyl carbamo-dithioate ~hereinafter referred to as mercapto carbamodi-thioate). The mercapto carbamodithioate is then contacted with an oxidation agent to prepare the dithiodialkylene--bis(mono- or dihydrocarbyl carbamodithioates).
Amines useful in this process include those which correspond to the formula HNRlR2 wherein R1 and R2 are as defined hereinbefore.
31,361-F -g-t,~ J
Specific illustra-tive examples of the amines contemplated herein are shown by the following:
(1) monoalkylamines including, for example, methyl~mine, ethylamine, propylamine, isopropylamine, n-butylamine, sec-butylamine, isobutylamine, pentyl-~ amines, hexylamines, cyclohexylamines, heptylamines, octylamines, dodecylamines, octadecylamines, eicosyl-` amines, triacontanylamines, benzylamine, chloro-~enzylamine, nitrobenzylamine, 2-ethoxyethylamine, 4-carbomethoxyhexylamine;
(2~ dialkylamines including, for example, dimethylamine, diethylamine, di-n-propylamine, diisopropylamine, di-,n-butylamine, di-sec-butylamine, diisobutylamine, di-tert-butylamine, dipentylamines, dihexylamines, dioctylamines, ditriacontanylamine, N-methylethylamine, N-methylpropylamine, N-methyl-octadecylamine, N-ethylhexylamine, N-ethyldodecyl-amine, N-propyldodecylamine;
(3) heterocyclic aliphatic secondary amines including, ~or example, piperazine, pyrrole, imidazoline, pyrazole, piperazine;
(4) arylamines including, for example, aniline, toluidine, anisidine, nitroaniline, bromoaniline, xylidines, 4-ethylaniline, naphthylamine;
(5) diarylamines including, for example, diphenylamine, N-phenyl-2-naphthylamine, N-phenyl-naphthylamine;
(6) alkylarylamines having from 1 to about 30 carbon atoms in the alkyl group attached either to the nitrogen atom or to the aryl group including, for example, N-ethylaniline, N-methyl-o-toluidine, N-methyl-p-toluidine, p-chloro-N~methylaniline, N,N'--dimethylphenylenediamine, 4-ethylaniline, 4-propyl-aniline, 4-bu-tylaniline, 4-decylaniline; and 31,361-F -10-
(7) aminoalkyl-substituted amines including, for example, ethylenediamine, diethylenetriamine, triethylenetetramine, 1,3-propylenediamine, di-1,3--propylenetriamine, 1,6,11,16-tetraa~ahexadecane.
The 1,3-ox~athiolane-2-thiones useful in this invention include those corresponding to the f~rmula S .. ...
O~ ~S
'4 '3 R R
wherein R3 and R4 are as defined hereinbefore, with the proviso that the R3 and R4 attached to one of the carbon atoms must be hydrogen, that is either the 4 carbon or the 5 carbon must be unsubstituted. Included are 1,3-oxa-thiolane-2-thione, 5-methyl-1,3-oxathiolane-2-thione, 5-ethyl-1,3-oxathiolane-2-thione, 5-propyl-1,3-oxathiolane--2-thione, 5-butyl-1,3-oxathiolane-2-thione, 5-pentyl-1,3--oxathiolane-2-thione, 5,5-dimethyl-1,3-oxathiolane-2--thione, 5,5-diethyl-1,3-oxathiolane-2-thione, 5,5-di-propyl-1,3-oxathiolane-2-thione, 5,5-dibutyl-1,3-oxa-thiolane-2-thione, 5,5-dipentyl-1,3-oxathiolane-2-thione, .25 5-phenyl-1,3-oxathiolane-2-thione. The 1,3-oxathiolane-2-; -thiones can be prepared by the method taught in U.S.
Patent 3,409,635.
The 1,3 dithiolane-2-thiones useful in this invention correspond to the formula 31,361-F -11-5R3~ C _.C -.R3 wherein R3 and R4 are as defined above and with the proviso that the R3 and R4 attached to one of the carbon atoms must be hydrogen, that is either -the 4 carbon or the 5 carbon must be unsubstituted. 1,3-Dithiolane-2-thiones are prepared by contacting carbon disulfide with an alkylene episulfide at a temperature of between 10C and 80C in the presence of a catalyst comprising an alkali metal halide, 2 to 12 weight percent water based on the alkali -~ metal halide, and an alkylsulfonium halide or methanol.
\
The 0-(2-mercaptoalkyl)mono- or dihydrocarbyl carbamothioates include those corresponding to the formula ; `
Rl S R3 R
:, wherein Rl, R2, R3 and R4 are as defined hereinbefore.
.
25The S-(2-mercaptoalkyl)mono- or dihydrocarbyl carbamothioates include those corresponding to the formula Rl O R3 R3 \ "
' ,NCS-C--C-SE~
" 30 R R4 R4 ..:
" 31,361-F -12-, ;`
. .~.
:
:
,;, ::
. ., wherein Rl, R2, R3 and R4 are as previously deflned.
The (2-mercaptoalkyl)mono- or dihydrocarbyl carbamodithioates correspond -to the formula Rl S R3 R3 ~ ~ 11 1 1 NCS-C- C-SH
wherein Rl, R2, R3 and R4 are as previously defined.
In the preparation of a S- or 0-~2-mercapto-alkyl~mono- or dihydrocarbyl carbamothioate or (2-mercapto-alkyl)mono- or dihydrocarbyl carbamodithioate, an amine and a l,3-oxathiolane-2-thione or l,3-dithiolane-2-thione are contacted in a suitable solvent. Preferably in a molar ratio of between about 0.95:l.0 to l.O:l.0 of l,3-oxa-thiolane-2-thione or l,3-dithiolane-2-thione to amine, more preferably in a l:l molar ratio. Although excesses of either reagent are within the scope of this invention, the reactants react in a stoichiometric manner such that the use of such an excess provides no significant advanta~e.
Suitable solvents include any inert solvent which dissolves the reactants. When high yields of 0,01_ -dithiodialkylene-bis(mono- or dihydrocarbyl carbamo-thioate) are desired, the solvent should be a nonpolarsolvent. Suitable nonpolar solvents include aromatlc hydrocarbons, aliphatic hydrocarbons, chlorinated aromatic hydrocarbons, aliphatic chlorinated hydrocarbons, cyclic ethers and aliphatic ethers. Examples of aromatic solvents include benzene, toluene, xylene, ethylbenzene and the.
like. Examples o~ aliphatic hydrocarbons include hexane, ~ .
`: :
; 31,~61-~ -13-; :
i . .
.
heptane, octane and the like. Examples of chlorinated aromatic hydrocarbons include monochlorobenzenes, dichloro-- benzenes, trichlorobenzenes, monochlorotoluene, monochloro-e-thylbenzene and the like. Chlorinated aliphatic hydro-carbons include chloromethane, dichloromethane, trichloro-methane, tetrachloromethane, chloroethane, dichloroethane, l,l,l-trichloroethane, viJnyl chloride, vinylidene chloride and the like. Cyclic ethers include tetrahydrofuran and ' the''like. Aliphatic ethers include ethyl ether'and the like.
Preferred solvents are cyclic ethers and aliphatic ethers, with tetrahydrofuran most preferred.
The first step can be run at an~ temperature at which the reaction rate-is reasonable and the product is acceptable. Preferred temperatures are between about -40C
and 30C, with between about 0C and 20C more preferred and between about 0C and 10C most preferred. Below -40C
the reaction rate is low, above 30C a siynificant amount of dialkylthiourea by-products is prepared.
The reaction time is generally between about 1 minute and several hours with between about 30 and 120 minutes being preferred.
After the amine and 1,3-oxathiolane-2-thione or 1,3-dithiolane-2-thione have reacted for a sufficient ;time to prepare the S-mercapto carbamothioate, 0-mercapto carbamothioate or mercapto carbamodithioate, an oxidant is added to the reaction solution to oxidize such compound to the disulfide carbamothioates and disulfide carbamodi-thioates claimed herein. Generally, a sufficient amount of oxidant is added to oxidize all of the S-mercapto 31,361-F -14--15- ~
carbamothioate, 0-mercapto thioate or mercapto carbamodi-thioate to the disulfide carbamothioates or disulfide carbamodithioates. Preferably, between about 0.5 and 1.5 moles of oxidant per mole of swch compounds is used.
More preferably, as this oxidation process is a mole ratio of 0.95:1 to 1.05:1 stoichiometric reaction, a 1:1 molar ratio is most preferred.
Suitable oxidants are those which oxidize mercaptans to disulfides. Examples of suitable oxidants are hydrogen peroxide, bromine, chlorine or oxygen or oxygen-containing gases in the presence of suitable catalysts. Hydrogen peroxide is the preferred oxidant.
When bromine or chlorine is used as the oxidant, the S,S'-dithiodialkylene bis(mono- or dihydrocarbyl carbamo-thioates) are prepared.-The oxidation can be run at any temperature atwhich the reaction rate is reasonable and product prepared does not have an unacceptable amount of by~product in it.
Preferable temperatures are between about -10C and 50C, more preferably between about 0C and 20C, and most ; preferably between about 0C and 10C. Below -10C the reaction rate is slow, above 50C significant amounts of unwanted by-products are prepared including dialkyl-thioureas.
.
The disulfide carbamothioatés and disulfide carbamodithioates are generally recovered by removing the solvents, for example, by stripping off the solvents on a rotary evaporator.
When a 1,3-oxathiolane-2-thione is the initial starting material, the product generally comprises a ~. ~
, .. .
~' .
~ 31,361-F -15 ;:
,.~;
.. . :
,~
,....
-16- ~
mixture of the O,O'-dithiodialkylene-bis(mono- or dihydro-carbyl carbamothioate), O,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamo-thioates) and S,S'-dithiodialkylene--bis(mono- or dihydrocarby:L carbamothioates). The O,O'--dithiodialkylene-bis(mono- or dihydrocarbyl carbamothio-ates) are preferred as they are better sulfide ore collectors; The ratio of the O,O'-dithi-odialkylene-bis-~mono- or dihydrocarbyl carbamothioates) to the S,S'--dithiodialkylene-bis(mono- or dihydroca~byl carbamothio-ates) and O,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamothioates) can be increased by using a more nonpolar solvent, running the reaction at lower temperatures and using shorter reaction times. The O,O'-dithiodialkylene--bis(mono- or dihydrocarbyl carbamothioates) are thermally less stable than the S,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamothioates) and at higher temperatures undergo rearrangement to the latter compounds.
In one preferred embodiment the process described herein is performed as follows. The 1,3-oxa-thiolane-2-thione is dissolved in a nonpolar solvent (i.e., tetrahydrofuran, dichloromethane or toluene). The solution is cooled to between 0C and 25C. A quanti-tative amount of amine is added slowly, while the temper-ature is maintained at between about 0C and 25C. After sufficient time for the reaction to go to completion (generally between 0.5 and 2.0 hours), a quantitative amount of oxidant (hydrogen peroxide) is added slowly while the temperature is maintained at between about 0C
and 25C. The reaction mixture is then allowed to warm to room temperature and react for at least about 0.5 hour.
The solvent and water are removed to obtain the crude product.
31,361-~ -16-~.
p The O,O'-dithiodialk~lene-bis(mono- or dih~dro-carbyl carbamothioates), O,S' dithiodialkylene-bis(mono-or dihydrocarbyl carbamo-thioates) and S,S'-dithiodi-alkylene-bis(mono- or dihydrocarbyl carhamothioa~es) are useful as collectors for sulfide ores in ~roth flo~,ation processes. Generally, the compounds are added to a frothing aqueous sulfide ore pulp in which they aid the sulfide ores in becoming attached to the air bubbles and being carried with the bubbles Into the froth.
Ores for which these compounds are useful include mineral ores containing copper, zinc, molybdenum, cobalt, nickel, lead, arsenic, silver, chromium, gold, platinum, uranium and mixtures thereof. It is preferable to use the disulfide carbamothioates and disulfide carbamodithio-ates as collectors for copper-containing sulfide minerals.
Examples of metal-containing sulfide minerals which may be concentrated by froth ~lotation using the disulfide carbamothioates and disulfide carbamodithioates of this invention as collectors include copper-bearing minerals such as, for example, covellite (CuS), chalcocite (Cu2S), chalcopyrite (CuFeS2), bornite (Cu5FeS4), cubanite (Cu2SFe4S5), vallerite (Cu2Fe4S7 or Cu3Fe~S7), enargite [Cu3(AsSb)S4], tetrahedrite (Cu3SbS2), tennanti-te (Cu12As4Sl3), cuprite (Cu20), tenorite (CuO), malachite [Cu2~0H)2C03], azurite [Cu3(0H)2C03], antlerite [Cu3S04(0H)4], brochantite [Cu4(0H)6S04], atacamite " [Cu2Cl~OH)3], chrysocolla (CuSiO7), fama-tinite [Cu3(SbAs)S4], and bournonite (PbCuSbS3); lead-bearing ~
minerals such as, for example, galena (PbS); an-timony--bearing minerals such as, for example, stibni-te (Sb2S4);
: zinc-bearing minerals such as, for example, sphalerite (ZnS), zincite (ZnO), and smithsonite (ZnC03); silver-` -bearing minerals such as, for example, argentite (Ag2S), stephanite (Ag5SbS4), and hessite (AgTe2); chromium-bearing 31,361-F -17-., , :.
;T~3~
minerals such as, for example, daubreelite (FeSCrS3) and chromite (FeOCr2O3); gold-bearing minerals such as, for example, sylvanite (AuAgTe2) and calaverite (AuTe), pla-tinum-bearing ores such as, for example, cooperite [Pt(AsS)2] and sperrylite (PtAs2); and uranium-bearing ores such as, for example, pitchblende [U2O5(U3O8)] and g~mmite (U~3nH2O).
The amount of the disulfide carbamothioate or disulfide carbamodithioate used for froth flotation depends upon the type of ore used, the grade of the ore, the size of the ore particles and the particular compound used.
Generally, that amount which separates the desired metal sulfide from the sulfide ore is suitable. Preferably between about 0.005 and 0.25 lb of disulfide carbamothio-ates or disulfide carbamodithioates per ton of ore, mostpreferably between about 0.015 and 0.08 lb per ton of ore is used.
Mixtures of O,O'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamothioates~ and S,S'-dithiodialkylene--bis(mono- or dihydrocarbyl carbamodithioates) are usually used in froth flotation of sulfide ores, because the process described hereinbefore prepares mixtures of the compounds. Each of the species can be used alone for froth flotation of sulfide ores. O,O'-dithiodialkylene--bis(mono- or dihydrocarbyl carbamothioates) and S,S'--dithiodialkylene-bis(mono- or dihydrocarbyl carbamothio.-ates are the preferred species as they are generally better collectors, with the O,O'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamothioates) being most preferred.
The froth flotation processes in which the disulfides of this invention are used, are those which are well known in the art. In most of these processes, use of ' 31,361-F -18-,, .
.
. ., .
.
- 1 9 ~
frothing agents is re~uired. It is contemplated that -the disulfide carbamothioa-tes and disulfide carbamodithioates of this invention will be used along wi-th fro-thers.
Further, the collectors of this invention can be used in mixtures with other known collectors.
Numerous collectors are known in flotation practice or have been proposed in the technical and patent literature; Generic examples include xan-thates, thio-- -carbamates, dithiophosphates, thiocarbanilide, xanthogen formates, alkylamines, quaternary ammonium compounds, sulfonates and the like. Any collector which is known in the art as suitable for the beneficiation by flotation of sulfide mineral ores can be used in this invention.
Further blends of known collectors can also be used in this invention.
Suitable frothers include some compounds which are also useful as collectors such as fatty acids, soaps, and alkyl aryl sulfonates, but the best frothers are those which have a minimum of collecting properties. They are polar-nonpolar molecules of the type C5~11OH, amyl alcohol or CloH17OH, the active constituent of the well-known frother pine oil. The aliphatic alcohols used as frothers preferably have chain lengths of 5 to 8 carbon atoms, provided there is sufficient branching in the chain.
Alcohols in the 10 to 12 carbon atom range are good frothers. Other examples include polyalkylene glycols, polyoxyalkylene paraffins and cresylic acids. ~lends of frothers may also be used. All frothers which are suitable for beneficiation of sulfide mineral ores by 3Q froth flotation can be used in this invention.
31,361-F -19--The disulfide carbamothioate and disulfide carbamodithioate collectors of this invention demonstrate good recoveries and rates of recovery.
~cific Embodiments The following examples are included for illustration and do not limit the scope of the invention or claims. Unless otherwise indicated, all parts, fractions and percen-tages are by weight.
In the following examples, the performance of the frothing processes described is shown by giving the rate constant of flotation and the amount of recovery at infinite time. These numbers are calculated by using the formula -kt y = R~ [1- kt ]
. . , wherein: y is the amount of mineral recovered at time t, k is the rate constant for the rate of recovery and R~ is the calculated amount of the mineral which would be recovered at infinite time. The amount recovered at various times is determined experimentally and the series of values are substituted into the equation to obtain the R and k. The above formula is explained in Klimpel, ~n "Selection of Chemical Reagents for Flotation", Ch. 45, pp. 907-934, Mineral Pr_cessin~ Plant Desiqn, 2d Ed., Eds.
Mular and Bhappu, published by Society of Mining Engineers, N.Y. ~1980).
, .
Example 1 - Preparation of 0,0'-dithio(l,l'-dimethyl)di-ethylene-bis(ethyl carbamothioate) A 250 ml 3-necked flask is equipped with a stirrer, thermometer, condenser (vented through a drying .,~ .
31,361-F -20-, . .
: `
, .; , tube), and an addi-tional funnel. To the flask is added 13.42 parts of 5-methyl-1,3-oxathiolane-2-thione and 42 parts of THF. The solution is cooled at 0C wikh an ice-water bath. To the mixture is added, dropwise, 5.90 parts propylamine o~er approximatel~ 15 minutes. The temperature ls maintained below 20C. After the exotherm is complete, the reaction solution is allowed to stand at 0C-20C for 30 minutes. The solution is cooled to 0C
and 11.3 parts of 30 percent H202 in H2O is added, drop-wise, maintaining the temperature below 20C. After theexotherm is complete, the solution is allowed to warm to room temperature and remain there for 1 hour or longer.
The tetrahydrofuran and water are removed in a ro-tovap at up -to 80C in an aspirator vacuum. The crude product of O,O'-dithio(l,l'-dimethyl)diethylene-bis(ethyl carbamo-thioate), 18.36 parts, is thus obtained.
Examples 2-12 - Experimental Procedure for Flotation of Copper Sulfide Ores Several of the O,O'- or S,S'-dithiodialkylene--bis(mono- or dihydrocarbyl carbamothioates) and S,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamo-dithioates~ of this invention and prior art collectors are used for the flotation of copper sulfide. The procedure for such flotation is described hereinafter. The results are compiled in Table I.
Pro~edure:
The flotation cell used is a 6.5 x 6.5 x 8-inch plexiglass container which holds approximately 2.8 liters of deionized water, ore, collector and frother. A rotating paddle is provided for skimming the frother from the top of the cell. An air inlet is placed in the bottom of the cell.
31,361-F -21-i A copper sulfide ore from the Inspiration Consolidated Copper Company is preground to -10 mesh.
Immediately before floatlng the ore is yround in a rod mill for an additional period of time to obtain the desired mesh size. The process for -this gri~ding is as follo~7s. Eigh-t rods of one inch each are put in a rod mill along ~ith lO00 g of ore, 0.6 g of lime (to bring the pH to 10.6), 600 g of deionized water, 0.05 lb of collec-tor per ton of ore (0.025-g), and the mixture ls ground at 60 rpm for about 25 minutes, until approximately 80 percent of the particles had a size of less than 200 mesh.
Thereafter, the slurry is transferxed to the float cell as described hereinbefore. The frother, Dowfroth~ 1012 (a polypropylene glycol ether available from The Dow Chemical ~ompany, Midland, Michigan) is added to the cell, 0.0~ lb per ton of ore (0.04 g). Deionized water is added to bring the water up to the desired level in the float cell. The mixture in the float cell is stirred at 900 rpm for 2 minutes to condikion the ore.
After 2 minutes of stirring, the air flow of 9 liters/-minute is started, wi.th continued stirring, and a paddle rotation of 10 rpm is started. Further water is added to maintain the water level. The froth from the cell is skimmed by the paddle into a collection tray. The froth 25 skimmed off is collected at intervals of 0.5, 1.5, 3.0, 5.0 and 8.0 minutes. Each sample is dried overnight in a forced air oven at 95C.
The samples are weighed and analyzed for copper ` content by plasma emission spectroscopy.
`:
The recovery and rate are calculated from the copper content and time of each sample using the equation ` described hereinbefore.
~ .
31,361-F -22-.
.
23 '~J'~ 3~
The procedure for the analysis by plasma emission spectroscopy is as follows. Into a 100-cc flask is placed 0.2 to 0.25 g of ore sample (approximately 2.0 y i it is a tailings sample, the ore lef-t in the cell after flo-tation). -To this is added 3.5 ml of concen-trated hydro-chloric acid and 5.0 ml of concentrated nitric acid. The - mixture is heated to boiling and boiled for 25 minutes, and then allowed to cool. To this is added 25 ml of ~ dei-onized water. The mixture is heated to boiling then allowed to cool. The mixture is filled to the volumetric line. A plasma emission spectrometer (Spectrospan IV) is used to determine the copper level in the solutions prepared. The copper emission line at 2135.98 nm is found to give a linear response with copper concentration. The instrument is standardized by the use of copper solution standards. When the sample solution is aspirated into the plasma, the concentration in ppm of Cu is shown by the - instrument by digital display. This ppm of Cu is converted into percent Cu in the original sample by the following e~uation:
% Cu in original sample = (gPrPamsCUOf(lsOamp)eluOsed) x 100%
The results are compiled in Table I.
, .
:,~
!.
:,' :~ 1 , . ~
,2,.~
~`i ~ ~ 31,361-F -23-~'' `: ' '.'..~
,,.,~, .
,~:
~: .
- 24 - ~ 6~6g3-3795 TABLE :[
Copper R Ganque Exam-ple Collector _ _ K8 minl- R K
2 Blank2 0.16 2.7 O.l6 0.03 4,5 3 Z-]l 0.55 4.3 0.54 0.03 3.7 4 Sodium Aerofloat 0.55 4.6 0.54 0.03 4.1 AFT 2083 0.55 2.7 0.56 0.03 0.8 ~-200 0.65 7.7 0.63 0.14 4.2 7 (cH3cH~NHcocHcH2s~2 0.62 4.5 0.62 0.07 3.7
The 1,3-ox~athiolane-2-thiones useful in this invention include those corresponding to the f~rmula S .. ...
O~ ~S
'4 '3 R R
wherein R3 and R4 are as defined hereinbefore, with the proviso that the R3 and R4 attached to one of the carbon atoms must be hydrogen, that is either the 4 carbon or the 5 carbon must be unsubstituted. Included are 1,3-oxa-thiolane-2-thione, 5-methyl-1,3-oxathiolane-2-thione, 5-ethyl-1,3-oxathiolane-2-thione, 5-propyl-1,3-oxathiolane--2-thione, 5-butyl-1,3-oxathiolane-2-thione, 5-pentyl-1,3--oxathiolane-2-thione, 5,5-dimethyl-1,3-oxathiolane-2--thione, 5,5-diethyl-1,3-oxathiolane-2-thione, 5,5-di-propyl-1,3-oxathiolane-2-thione, 5,5-dibutyl-1,3-oxa-thiolane-2-thione, 5,5-dipentyl-1,3-oxathiolane-2-thione, .25 5-phenyl-1,3-oxathiolane-2-thione. The 1,3-oxathiolane-2-; -thiones can be prepared by the method taught in U.S.
Patent 3,409,635.
The 1,3 dithiolane-2-thiones useful in this invention correspond to the formula 31,361-F -11-5R3~ C _.C -.R3 wherein R3 and R4 are as defined above and with the proviso that the R3 and R4 attached to one of the carbon atoms must be hydrogen, that is either -the 4 carbon or the 5 carbon must be unsubstituted. 1,3-Dithiolane-2-thiones are prepared by contacting carbon disulfide with an alkylene episulfide at a temperature of between 10C and 80C in the presence of a catalyst comprising an alkali metal halide, 2 to 12 weight percent water based on the alkali -~ metal halide, and an alkylsulfonium halide or methanol.
\
The 0-(2-mercaptoalkyl)mono- or dihydrocarbyl carbamothioates include those corresponding to the formula ; `
Rl S R3 R
:, wherein Rl, R2, R3 and R4 are as defined hereinbefore.
.
25The S-(2-mercaptoalkyl)mono- or dihydrocarbyl carbamothioates include those corresponding to the formula Rl O R3 R3 \ "
' ,NCS-C--C-SE~
" 30 R R4 R4 ..:
" 31,361-F -12-, ;`
. .~.
:
:
,;, ::
. ., wherein Rl, R2, R3 and R4 are as previously deflned.
The (2-mercaptoalkyl)mono- or dihydrocarbyl carbamodithioates correspond -to the formula Rl S R3 R3 ~ ~ 11 1 1 NCS-C- C-SH
wherein Rl, R2, R3 and R4 are as previously defined.
In the preparation of a S- or 0-~2-mercapto-alkyl~mono- or dihydrocarbyl carbamothioate or (2-mercapto-alkyl)mono- or dihydrocarbyl carbamodithioate, an amine and a l,3-oxathiolane-2-thione or l,3-dithiolane-2-thione are contacted in a suitable solvent. Preferably in a molar ratio of between about 0.95:l.0 to l.O:l.0 of l,3-oxa-thiolane-2-thione or l,3-dithiolane-2-thione to amine, more preferably in a l:l molar ratio. Although excesses of either reagent are within the scope of this invention, the reactants react in a stoichiometric manner such that the use of such an excess provides no significant advanta~e.
Suitable solvents include any inert solvent which dissolves the reactants. When high yields of 0,01_ -dithiodialkylene-bis(mono- or dihydrocarbyl carbamo-thioate) are desired, the solvent should be a nonpolarsolvent. Suitable nonpolar solvents include aromatlc hydrocarbons, aliphatic hydrocarbons, chlorinated aromatic hydrocarbons, aliphatic chlorinated hydrocarbons, cyclic ethers and aliphatic ethers. Examples of aromatic solvents include benzene, toluene, xylene, ethylbenzene and the.
like. Examples o~ aliphatic hydrocarbons include hexane, ~ .
`: :
; 31,~61-~ -13-; :
i . .
.
heptane, octane and the like. Examples of chlorinated aromatic hydrocarbons include monochlorobenzenes, dichloro-- benzenes, trichlorobenzenes, monochlorotoluene, monochloro-e-thylbenzene and the like. Chlorinated aliphatic hydro-carbons include chloromethane, dichloromethane, trichloro-methane, tetrachloromethane, chloroethane, dichloroethane, l,l,l-trichloroethane, viJnyl chloride, vinylidene chloride and the like. Cyclic ethers include tetrahydrofuran and ' the''like. Aliphatic ethers include ethyl ether'and the like.
Preferred solvents are cyclic ethers and aliphatic ethers, with tetrahydrofuran most preferred.
The first step can be run at an~ temperature at which the reaction rate-is reasonable and the product is acceptable. Preferred temperatures are between about -40C
and 30C, with between about 0C and 20C more preferred and between about 0C and 10C most preferred. Below -40C
the reaction rate is low, above 30C a siynificant amount of dialkylthiourea by-products is prepared.
The reaction time is generally between about 1 minute and several hours with between about 30 and 120 minutes being preferred.
After the amine and 1,3-oxathiolane-2-thione or 1,3-dithiolane-2-thione have reacted for a sufficient ;time to prepare the S-mercapto carbamothioate, 0-mercapto carbamothioate or mercapto carbamodithioate, an oxidant is added to the reaction solution to oxidize such compound to the disulfide carbamothioates and disulfide carbamodi-thioates claimed herein. Generally, a sufficient amount of oxidant is added to oxidize all of the S-mercapto 31,361-F -14--15- ~
carbamothioate, 0-mercapto thioate or mercapto carbamodi-thioate to the disulfide carbamothioates or disulfide carbamodithioates. Preferably, between about 0.5 and 1.5 moles of oxidant per mole of swch compounds is used.
More preferably, as this oxidation process is a mole ratio of 0.95:1 to 1.05:1 stoichiometric reaction, a 1:1 molar ratio is most preferred.
Suitable oxidants are those which oxidize mercaptans to disulfides. Examples of suitable oxidants are hydrogen peroxide, bromine, chlorine or oxygen or oxygen-containing gases in the presence of suitable catalysts. Hydrogen peroxide is the preferred oxidant.
When bromine or chlorine is used as the oxidant, the S,S'-dithiodialkylene bis(mono- or dihydrocarbyl carbamo-thioates) are prepared.-The oxidation can be run at any temperature atwhich the reaction rate is reasonable and product prepared does not have an unacceptable amount of by~product in it.
Preferable temperatures are between about -10C and 50C, more preferably between about 0C and 20C, and most ; preferably between about 0C and 10C. Below -10C the reaction rate is slow, above 50C significant amounts of unwanted by-products are prepared including dialkyl-thioureas.
.
The disulfide carbamothioatés and disulfide carbamodithioates are generally recovered by removing the solvents, for example, by stripping off the solvents on a rotary evaporator.
When a 1,3-oxathiolane-2-thione is the initial starting material, the product generally comprises a ~. ~
, .. .
~' .
~ 31,361-F -15 ;:
,.~;
.. . :
,~
,....
-16- ~
mixture of the O,O'-dithiodialkylene-bis(mono- or dihydro-carbyl carbamothioate), O,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamo-thioates) and S,S'-dithiodialkylene--bis(mono- or dihydrocarby:L carbamothioates). The O,O'--dithiodialkylene-bis(mono- or dihydrocarbyl carbamothio-ates) are preferred as they are better sulfide ore collectors; The ratio of the O,O'-dithi-odialkylene-bis-~mono- or dihydrocarbyl carbamothioates) to the S,S'--dithiodialkylene-bis(mono- or dihydroca~byl carbamothio-ates) and O,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamothioates) can be increased by using a more nonpolar solvent, running the reaction at lower temperatures and using shorter reaction times. The O,O'-dithiodialkylene--bis(mono- or dihydrocarbyl carbamothioates) are thermally less stable than the S,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamothioates) and at higher temperatures undergo rearrangement to the latter compounds.
In one preferred embodiment the process described herein is performed as follows. The 1,3-oxa-thiolane-2-thione is dissolved in a nonpolar solvent (i.e., tetrahydrofuran, dichloromethane or toluene). The solution is cooled to between 0C and 25C. A quanti-tative amount of amine is added slowly, while the temper-ature is maintained at between about 0C and 25C. After sufficient time for the reaction to go to completion (generally between 0.5 and 2.0 hours), a quantitative amount of oxidant (hydrogen peroxide) is added slowly while the temperature is maintained at between about 0C
and 25C. The reaction mixture is then allowed to warm to room temperature and react for at least about 0.5 hour.
The solvent and water are removed to obtain the crude product.
31,361-~ -16-~.
p The O,O'-dithiodialk~lene-bis(mono- or dih~dro-carbyl carbamothioates), O,S' dithiodialkylene-bis(mono-or dihydrocarbyl carbamo-thioates) and S,S'-dithiodi-alkylene-bis(mono- or dihydrocarbyl carhamothioa~es) are useful as collectors for sulfide ores in ~roth flo~,ation processes. Generally, the compounds are added to a frothing aqueous sulfide ore pulp in which they aid the sulfide ores in becoming attached to the air bubbles and being carried with the bubbles Into the froth.
Ores for which these compounds are useful include mineral ores containing copper, zinc, molybdenum, cobalt, nickel, lead, arsenic, silver, chromium, gold, platinum, uranium and mixtures thereof. It is preferable to use the disulfide carbamothioates and disulfide carbamodithio-ates as collectors for copper-containing sulfide minerals.
Examples of metal-containing sulfide minerals which may be concentrated by froth ~lotation using the disulfide carbamothioates and disulfide carbamodithioates of this invention as collectors include copper-bearing minerals such as, for example, covellite (CuS), chalcocite (Cu2S), chalcopyrite (CuFeS2), bornite (Cu5FeS4), cubanite (Cu2SFe4S5), vallerite (Cu2Fe4S7 or Cu3Fe~S7), enargite [Cu3(AsSb)S4], tetrahedrite (Cu3SbS2), tennanti-te (Cu12As4Sl3), cuprite (Cu20), tenorite (CuO), malachite [Cu2~0H)2C03], azurite [Cu3(0H)2C03], antlerite [Cu3S04(0H)4], brochantite [Cu4(0H)6S04], atacamite " [Cu2Cl~OH)3], chrysocolla (CuSiO7), fama-tinite [Cu3(SbAs)S4], and bournonite (PbCuSbS3); lead-bearing ~
minerals such as, for example, galena (PbS); an-timony--bearing minerals such as, for example, stibni-te (Sb2S4);
: zinc-bearing minerals such as, for example, sphalerite (ZnS), zincite (ZnO), and smithsonite (ZnC03); silver-` -bearing minerals such as, for example, argentite (Ag2S), stephanite (Ag5SbS4), and hessite (AgTe2); chromium-bearing 31,361-F -17-., , :.
;T~3~
minerals such as, for example, daubreelite (FeSCrS3) and chromite (FeOCr2O3); gold-bearing minerals such as, for example, sylvanite (AuAgTe2) and calaverite (AuTe), pla-tinum-bearing ores such as, for example, cooperite [Pt(AsS)2] and sperrylite (PtAs2); and uranium-bearing ores such as, for example, pitchblende [U2O5(U3O8)] and g~mmite (U~3nH2O).
The amount of the disulfide carbamothioate or disulfide carbamodithioate used for froth flotation depends upon the type of ore used, the grade of the ore, the size of the ore particles and the particular compound used.
Generally, that amount which separates the desired metal sulfide from the sulfide ore is suitable. Preferably between about 0.005 and 0.25 lb of disulfide carbamothio-ates or disulfide carbamodithioates per ton of ore, mostpreferably between about 0.015 and 0.08 lb per ton of ore is used.
Mixtures of O,O'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamothioates~ and S,S'-dithiodialkylene--bis(mono- or dihydrocarbyl carbamodithioates) are usually used in froth flotation of sulfide ores, because the process described hereinbefore prepares mixtures of the compounds. Each of the species can be used alone for froth flotation of sulfide ores. O,O'-dithiodialkylene--bis(mono- or dihydrocarbyl carbamothioates) and S,S'--dithiodialkylene-bis(mono- or dihydrocarbyl carbamothio.-ates are the preferred species as they are generally better collectors, with the O,O'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamothioates) being most preferred.
The froth flotation processes in which the disulfides of this invention are used, are those which are well known in the art. In most of these processes, use of ' 31,361-F -18-,, .
.
. ., .
.
- 1 9 ~
frothing agents is re~uired. It is contemplated that -the disulfide carbamothioa-tes and disulfide carbamodithioates of this invention will be used along wi-th fro-thers.
Further, the collectors of this invention can be used in mixtures with other known collectors.
Numerous collectors are known in flotation practice or have been proposed in the technical and patent literature; Generic examples include xan-thates, thio-- -carbamates, dithiophosphates, thiocarbanilide, xanthogen formates, alkylamines, quaternary ammonium compounds, sulfonates and the like. Any collector which is known in the art as suitable for the beneficiation by flotation of sulfide mineral ores can be used in this invention.
Further blends of known collectors can also be used in this invention.
Suitable frothers include some compounds which are also useful as collectors such as fatty acids, soaps, and alkyl aryl sulfonates, but the best frothers are those which have a minimum of collecting properties. They are polar-nonpolar molecules of the type C5~11OH, amyl alcohol or CloH17OH, the active constituent of the well-known frother pine oil. The aliphatic alcohols used as frothers preferably have chain lengths of 5 to 8 carbon atoms, provided there is sufficient branching in the chain.
Alcohols in the 10 to 12 carbon atom range are good frothers. Other examples include polyalkylene glycols, polyoxyalkylene paraffins and cresylic acids. ~lends of frothers may also be used. All frothers which are suitable for beneficiation of sulfide mineral ores by 3Q froth flotation can be used in this invention.
31,361-F -19--The disulfide carbamothioate and disulfide carbamodithioate collectors of this invention demonstrate good recoveries and rates of recovery.
~cific Embodiments The following examples are included for illustration and do not limit the scope of the invention or claims. Unless otherwise indicated, all parts, fractions and percen-tages are by weight.
In the following examples, the performance of the frothing processes described is shown by giving the rate constant of flotation and the amount of recovery at infinite time. These numbers are calculated by using the formula -kt y = R~ [1- kt ]
. . , wherein: y is the amount of mineral recovered at time t, k is the rate constant for the rate of recovery and R~ is the calculated amount of the mineral which would be recovered at infinite time. The amount recovered at various times is determined experimentally and the series of values are substituted into the equation to obtain the R and k. The above formula is explained in Klimpel, ~n "Selection of Chemical Reagents for Flotation", Ch. 45, pp. 907-934, Mineral Pr_cessin~ Plant Desiqn, 2d Ed., Eds.
Mular and Bhappu, published by Society of Mining Engineers, N.Y. ~1980).
, .
Example 1 - Preparation of 0,0'-dithio(l,l'-dimethyl)di-ethylene-bis(ethyl carbamothioate) A 250 ml 3-necked flask is equipped with a stirrer, thermometer, condenser (vented through a drying .,~ .
31,361-F -20-, . .
: `
, .; , tube), and an addi-tional funnel. To the flask is added 13.42 parts of 5-methyl-1,3-oxathiolane-2-thione and 42 parts of THF. The solution is cooled at 0C wikh an ice-water bath. To the mixture is added, dropwise, 5.90 parts propylamine o~er approximatel~ 15 minutes. The temperature ls maintained below 20C. After the exotherm is complete, the reaction solution is allowed to stand at 0C-20C for 30 minutes. The solution is cooled to 0C
and 11.3 parts of 30 percent H202 in H2O is added, drop-wise, maintaining the temperature below 20C. After theexotherm is complete, the solution is allowed to warm to room temperature and remain there for 1 hour or longer.
The tetrahydrofuran and water are removed in a ro-tovap at up -to 80C in an aspirator vacuum. The crude product of O,O'-dithio(l,l'-dimethyl)diethylene-bis(ethyl carbamo-thioate), 18.36 parts, is thus obtained.
Examples 2-12 - Experimental Procedure for Flotation of Copper Sulfide Ores Several of the O,O'- or S,S'-dithiodialkylene--bis(mono- or dihydrocarbyl carbamothioates) and S,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamo-dithioates~ of this invention and prior art collectors are used for the flotation of copper sulfide. The procedure for such flotation is described hereinafter. The results are compiled in Table I.
Pro~edure:
The flotation cell used is a 6.5 x 6.5 x 8-inch plexiglass container which holds approximately 2.8 liters of deionized water, ore, collector and frother. A rotating paddle is provided for skimming the frother from the top of the cell. An air inlet is placed in the bottom of the cell.
31,361-F -21-i A copper sulfide ore from the Inspiration Consolidated Copper Company is preground to -10 mesh.
Immediately before floatlng the ore is yround in a rod mill for an additional period of time to obtain the desired mesh size. The process for -this gri~ding is as follo~7s. Eigh-t rods of one inch each are put in a rod mill along ~ith lO00 g of ore, 0.6 g of lime (to bring the pH to 10.6), 600 g of deionized water, 0.05 lb of collec-tor per ton of ore (0.025-g), and the mixture ls ground at 60 rpm for about 25 minutes, until approximately 80 percent of the particles had a size of less than 200 mesh.
Thereafter, the slurry is transferxed to the float cell as described hereinbefore. The frother, Dowfroth~ 1012 (a polypropylene glycol ether available from The Dow Chemical ~ompany, Midland, Michigan) is added to the cell, 0.0~ lb per ton of ore (0.04 g). Deionized water is added to bring the water up to the desired level in the float cell. The mixture in the float cell is stirred at 900 rpm for 2 minutes to condikion the ore.
After 2 minutes of stirring, the air flow of 9 liters/-minute is started, wi.th continued stirring, and a paddle rotation of 10 rpm is started. Further water is added to maintain the water level. The froth from the cell is skimmed by the paddle into a collection tray. The froth 25 skimmed off is collected at intervals of 0.5, 1.5, 3.0, 5.0 and 8.0 minutes. Each sample is dried overnight in a forced air oven at 95C.
The samples are weighed and analyzed for copper ` content by plasma emission spectroscopy.
`:
The recovery and rate are calculated from the copper content and time of each sample using the equation ` described hereinbefore.
~ .
31,361-F -22-.
.
23 '~J'~ 3~
The procedure for the analysis by plasma emission spectroscopy is as follows. Into a 100-cc flask is placed 0.2 to 0.25 g of ore sample (approximately 2.0 y i it is a tailings sample, the ore lef-t in the cell after flo-tation). -To this is added 3.5 ml of concen-trated hydro-chloric acid and 5.0 ml of concentrated nitric acid. The - mixture is heated to boiling and boiled for 25 minutes, and then allowed to cool. To this is added 25 ml of ~ dei-onized water. The mixture is heated to boiling then allowed to cool. The mixture is filled to the volumetric line. A plasma emission spectrometer (Spectrospan IV) is used to determine the copper level in the solutions prepared. The copper emission line at 2135.98 nm is found to give a linear response with copper concentration. The instrument is standardized by the use of copper solution standards. When the sample solution is aspirated into the plasma, the concentration in ppm of Cu is shown by the - instrument by digital display. This ppm of Cu is converted into percent Cu in the original sample by the following e~uation:
% Cu in original sample = (gPrPamsCUOf(lsOamp)eluOsed) x 100%
The results are compiled in Table I.
, .
:,~
!.
:,' :~ 1 , . ~
,2,.~
~`i ~ ~ 31,361-F -23-~'' `: ' '.'..~
,,.,~, .
,~:
~: .
- 24 - ~ 6~6g3-3795 TABLE :[
Copper R Ganque Exam-ple Collector _ _ K8 minl- R K
2 Blank2 0.16 2.7 O.l6 0.03 4,5 3 Z-]l 0.55 4.3 0.54 0.03 3.7 4 Sodium Aerofloat 0.55 4.6 0.54 0.03 4.1 AFT 2083 0.55 2.7 0.56 0.03 0.8 ~-200 0.65 7.7 0.63 0.14 4.2 7 (cH3cH~NHcocHcH2s~2 0.62 4.5 0.62 0.07 3.7
8 (CH3CH2NHC0CHcH2s~2 0.71 6.5 0.70 0.08 3.7 g (cH3cH2cH2NHcolcHcH2s~2 0.67 7.1 0.66 0.15 4.6 (CH3CH2NHCSCHCH2S~2 0.55 4.8 0.52 0.04 4.8 11 (cH3cH2NHcsclHcH2s~2 0.65 4.40.65 0.04 3.6 12 (CH3CH2NHCSCIHCH2S~2 0.54 3.80.53 0.54 4.1 R 8 min is the actual recovery after 8 minutes.
2Blank means no collector has been added.
3AFT 208~ Trade-mark of American Cyanamid is a mixture of Na diethyl dithiophosphate and Na di-sec-butyl dithiophosphate.
.
3 ~
Examples 2 6 are not embodiments of -this invention.
Examples 13-22 - Experimental Procedure for Flotation of Copper Sulfide Ores Several of the disulfide carbamothioates of this invention and prior art collectors are used for the flo-tation of copper sulfide. The procedure for such flotation is described hereinafter. The results are compiled in Table II.
Procedure:
The flotation cell used is a container which holds approximately 1.7 liters of deionized water, ore, collector and frother. A rotating double-paddle is provided for skimming t~e frother from the top of the cell into a collecting tray. An air inlet is placed in the bottom of the cell.
` Kennecott ore containing copper sulfide from the Arthur Mill in Utah is preground to -10 mesh. Immediately before floating, the ore is ground in a rod mill for an additional period of time to obtain the desired mesh size.
', The process for this grinding is as follows. Eight rods of one inch each are put in a rod mill along with 500 g of ~t ore, 1 g of NaCO3 and 333 g of deionized water. Lime is added to adjust the pH to between 10.0 and 10.2, the collector is added and the mixture is ground at 60 rpm for about 5 minutes, until approximately 52 percent of -the s~ particles had a size of less than 200 mesh.
Thereafter, the slurry is transferred to the ~t~ float cell as described hereinbefore. The frother, methyl ;~ 30 isobutyl carbinol (50 ~l) is added to the cell. Deionized ~ water is added to bring the water up to the desired level ;~
`~ 31,361-F -25-. .
::j ,., . j .
,.. .
~,, 7~ ~;3 in the float cell. The mixture in the float cell is stirred at 1050 rpm for 2 minutes to condition the ore.
After 2 minutes of s-tirring, the air flo~l o~ l9 ft3/hour is started, with continued stirring, and a paddle rotation of 12 rpm is starte~. Further water is added to maintain the water level. The froth from the cell is skimmed by the paddle into a collection tray. The froth skimmed off is collected at intervals of 0.5, l.0, 2.0, 4.0 and 8-.0 minute~s. Each sample- is dried overnight in a forced air oven at about 100C.
The samples are weighed and analyzed for copper content by plasma emission spectroscopy.
The procedure for the analysis by plasma emission spectroscopy is as follows. Into a lO0-ml flask is placed 0.2 to 0.25 g of ore sample (approximately 2.0 g if it is a tailings sample, the ore left in the cell after flotation). To this is added 3.5 ml of concentrated hydro-chloric acid and 5 0 ml of concentrated nitric acid. The mixture is heated to boiling and boiled for 25 minutes, and then allowed to cool. To this is added 25 ml of deionized water. The mixture is heated to boiling then allowed to cool. The mixture is filled to the volumetric line. A plasma emission spectrometer (Spectrospan IV) is used to determine the copper level in the solutions prepared. The copper emission line at 2135.98 nm is found to give a linear response with copper concentration. The instrument is standardized by the use of copper solution standards. When the sample solution is aspirated into the plasma, the concentration in ppm of Cu is shown by the instrument by digital display. This ppm of Cu is converted into percent Cu in the original sample by the following equation:
31,361-F -26-:
. . .
% Cu in original sample = ((PrPmsCOU)(1amp~ used) x 100% .
The percent recovery and rate are calculated by subs-tituting the weight of the copper and the time each sample was taken into the e~uation described hereinbefore.
Table II demonstrates that the compounds of this invention demonstrate activity comparable to -the activity of collectors presently being used commercially. Further, the preferred collectors of this invention can give recoveries around 90 percent with rates of 9.0 or better.
, 31,361-F -27-'' ':
- ~ .
,, .
~ . .
TABLE II
Copper Exam- R 8 ple Collector CC1 R K min~ R K
13 sodium isopro- 0.02 0.90 12.4 0.90 0.093 15.2 pyl xanthate 14 potassium amyl 0.02 0.91 11.5 0.91 0.106 18.8 xanthate 15A-211 0.02 0.89 7.8 0.89 0.052 8.3 16Z-200 0.02 0.91 7.3 0.91 0.091 6.8 10 17Z-200 0.01 0.92 6.8 - 0.128 10.7 S
183.(RlNHCOCHCH2St2 0.05 0.90 9.8 0.90 0.096 11.2 R
193 (RlNHCOCHCH2S~2 0.025 0.89 10.7 0.90 0.089 12.6 R
S
203 (R NHcocHcH2st2 0.025 0.89 11.0 0.89 0.092 14.1 R
S
213 ~RlNHCOCHCH2S~2 0.015 0.88 9.0 0.88 0.091 12.1 O
22 (RlNHCSCHCH2S~2 0.015 0.69 2.9 0.69 0.066 16.0 R
1Collector Concentration.
2R 8 min is the actual recovery after 8 minutes.
3R1 and R2 are CH3CH2 above.
.,; .
`
~ 31,361-F -28-~.:
.
:
2Blank means no collector has been added.
3AFT 208~ Trade-mark of American Cyanamid is a mixture of Na diethyl dithiophosphate and Na di-sec-butyl dithiophosphate.
.
3 ~
Examples 2 6 are not embodiments of -this invention.
Examples 13-22 - Experimental Procedure for Flotation of Copper Sulfide Ores Several of the disulfide carbamothioates of this invention and prior art collectors are used for the flo-tation of copper sulfide. The procedure for such flotation is described hereinafter. The results are compiled in Table II.
Procedure:
The flotation cell used is a container which holds approximately 1.7 liters of deionized water, ore, collector and frother. A rotating double-paddle is provided for skimming t~e frother from the top of the cell into a collecting tray. An air inlet is placed in the bottom of the cell.
` Kennecott ore containing copper sulfide from the Arthur Mill in Utah is preground to -10 mesh. Immediately before floating, the ore is ground in a rod mill for an additional period of time to obtain the desired mesh size.
', The process for this grinding is as follows. Eight rods of one inch each are put in a rod mill along with 500 g of ~t ore, 1 g of NaCO3 and 333 g of deionized water. Lime is added to adjust the pH to between 10.0 and 10.2, the collector is added and the mixture is ground at 60 rpm for about 5 minutes, until approximately 52 percent of -the s~ particles had a size of less than 200 mesh.
Thereafter, the slurry is transferred to the ~t~ float cell as described hereinbefore. The frother, methyl ;~ 30 isobutyl carbinol (50 ~l) is added to the cell. Deionized ~ water is added to bring the water up to the desired level ;~
`~ 31,361-F -25-. .
::j ,., . j .
,.. .
~,, 7~ ~;3 in the float cell. The mixture in the float cell is stirred at 1050 rpm for 2 minutes to condition the ore.
After 2 minutes of s-tirring, the air flo~l o~ l9 ft3/hour is started, with continued stirring, and a paddle rotation of 12 rpm is starte~. Further water is added to maintain the water level. The froth from the cell is skimmed by the paddle into a collection tray. The froth skimmed off is collected at intervals of 0.5, l.0, 2.0, 4.0 and 8-.0 minute~s. Each sample- is dried overnight in a forced air oven at about 100C.
The samples are weighed and analyzed for copper content by plasma emission spectroscopy.
The procedure for the analysis by plasma emission spectroscopy is as follows. Into a lO0-ml flask is placed 0.2 to 0.25 g of ore sample (approximately 2.0 g if it is a tailings sample, the ore left in the cell after flotation). To this is added 3.5 ml of concentrated hydro-chloric acid and 5 0 ml of concentrated nitric acid. The mixture is heated to boiling and boiled for 25 minutes, and then allowed to cool. To this is added 25 ml of deionized water. The mixture is heated to boiling then allowed to cool. The mixture is filled to the volumetric line. A plasma emission spectrometer (Spectrospan IV) is used to determine the copper level in the solutions prepared. The copper emission line at 2135.98 nm is found to give a linear response with copper concentration. The instrument is standardized by the use of copper solution standards. When the sample solution is aspirated into the plasma, the concentration in ppm of Cu is shown by the instrument by digital display. This ppm of Cu is converted into percent Cu in the original sample by the following equation:
31,361-F -26-:
. . .
% Cu in original sample = ((PrPmsCOU)(1amp~ used) x 100% .
The percent recovery and rate are calculated by subs-tituting the weight of the copper and the time each sample was taken into the e~uation described hereinbefore.
Table II demonstrates that the compounds of this invention demonstrate activity comparable to -the activity of collectors presently being used commercially. Further, the preferred collectors of this invention can give recoveries around 90 percent with rates of 9.0 or better.
, 31,361-F -27-'' ':
- ~ .
,, .
~ . .
TABLE II
Copper Exam- R 8 ple Collector CC1 R K min~ R K
13 sodium isopro- 0.02 0.90 12.4 0.90 0.093 15.2 pyl xanthate 14 potassium amyl 0.02 0.91 11.5 0.91 0.106 18.8 xanthate 15A-211 0.02 0.89 7.8 0.89 0.052 8.3 16Z-200 0.02 0.91 7.3 0.91 0.091 6.8 10 17Z-200 0.01 0.92 6.8 - 0.128 10.7 S
183.(RlNHCOCHCH2St2 0.05 0.90 9.8 0.90 0.096 11.2 R
193 (RlNHCOCHCH2S~2 0.025 0.89 10.7 0.90 0.089 12.6 R
S
203 (R NHcocHcH2st2 0.025 0.89 11.0 0.89 0.092 14.1 R
S
213 ~RlNHCOCHCH2S~2 0.015 0.88 9.0 0.88 0.091 12.1 O
22 (RlNHCSCHCH2S~2 0.015 0.69 2.9 0.69 0.066 16.0 R
1Collector Concentration.
2R 8 min is the actual recovery after 8 minutes.
3R1 and R2 are CH3CH2 above.
.,; .
`
~ 31,361-F -28-~.:
.
:
Claims (23)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A compound comprising O,O'-, O,S'- or S,S'-dithiodi-alkylene-bis-(mono- or dihydrocarbyl carbamothioates) and S,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamodithioates) which correspond to the formula wherein R1 is separately in each occurrence hydrogen or C1-20 hydro-carbyl;
R2 is separately in each occurrence C1-20 hydrocarbyl;
R3 is separately in each occurrence hydrogen or C1-20 hydro-carbyl;
R4 is separately in each occurrence hydrogen or C1-20 hydro-carbyl;
X is separately in each occurrence O or S; and Y is separately in each occurrence O or S;
with the proviso that X and Y cannot both be oxygen and with the further proviso that at least one R3 and one R4 on the same carbon atom on each alkylene moiety must be hydrogen.
R2 is separately in each occurrence C1-20 hydrocarbyl;
R3 is separately in each occurrence hydrogen or C1-20 hydro-carbyl;
R4 is separately in each occurrence hydrogen or C1-20 hydro-carbyl;
X is separately in each occurrence O or S; and Y is separately in each occurrence O or S;
with the proviso that X and Y cannot both be oxygen and with the further proviso that at least one R3 and one R4 on the same carbon atom on each alkylene moiety must be hydrogen.
2. The O,O'-, S,S'-dithiodialkylene-bis(mono- or dihydro-carbyl carbamothioates) of Claim 1 which correspond to the formula wherein R1 is separately in each occurrence hydrogen or C1-20 hydrocarbyl;
R2 is separately in each occurrence C1-20 hydrocarbyl;
R3 is separately in each occurrence hydrogen or C1-20 hydrocarbyl;
R4 is separately in each occurrence hydrogen or C1-20 hydrocarbyl, X is separately in each occurrence O or S; and Y is separately in each occurrence O or S;
with the proviso that X and Y cannot both be the same and with the further proviso that at least one R3 and one R4 on the same carbon atom on each alkylene moiety must be hydrogen.
R2 is separately in each occurrence C1-20 hydrocarbyl;
R3 is separately in each occurrence hydrogen or C1-20 hydrocarbyl;
R4 is separately in each occurrence hydrogen or C1-20 hydrocarbyl, X is separately in each occurrence O or S; and Y is separately in each occurrence O or S;
with the proviso that X and Y cannot both be the same and with the further proviso that at least one R3 and one R4 on the same carbon atom on each alkylene moiety must be hydrogen.
3. The O,O'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamothioates) of Claim 2 which correspond to the formula wherein R1, R2, R3 and R4 are as defined in Claim 2,
4. The S,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamothioates) of Claim 2 which correspond to the formula wherein R1, R2, R3 and R4 are as defined in Claim 2.
5. The dithiodialkylene-bis(mono- or dihydrocarbyl carbamodithioates) of Claim 1 which correspond to the formula wherein R1, R2, R3 and R4 are as defined in Claim 2.
6. The disulfides of Claim 1 wherein R2 is C1-20 alkyl or phenyl.
7. The disulfides of Claim 1 wherein R2 is C2-6 alkyl.
8. The disulfides of Claim 1 wherein R3 is hydrogen or C1-20 alkyl and R4 is C1-20 alkyl.
9. The disulfides of Claim 8 wherein R3 is hydrogen or C1-4 alkyl and R4 is C1-4 alkyl.
10. A process for the preparation of O,O'-, O,S'- or S,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamothioates) or S,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamodi-thioates) which comprises (1) contacting a 1,3-oxathiolane-2-thione or 1,3-dithiolane-2-thione with a primary or secondary amine in a nonpolar solvent under conditions such that an O- or S-(2-mercaptoalkyl)mono- or dihydrocarbyl carbamothioate or S-(2-mercaptoalkyl)mono-or di-hydrocarbyl carbamothioate is formed;
(2) adding to the above reaction solution an oxidant which is capable of oxidizing the mercapto moiety under conditions such that an O,O'- O,S'- or S,S'-dithiodialkylene-bis(mono- or dihydro-carbyl carbamothioate) or S,S'-dithiodialkylene-bis(mono- or di-hydrocarbyl carbamodithioate) is prepared;
wherein the amine corresponds to the formula NHR1R2, the 1,3-oxathiolane-2-thione corresponds to the formula the 1,3-dithiolane-2-thiones correspond to the formula the O-(2-mercaptoalkyl)mono- or dihydrocarbyl carbamothioate corresponds to the formula the S-(2-mercaptoalkyl)mono- or dihydrocarbyl carbamothioate corresponds to the formula the (2-mercaptoalkyl)mono- or dihydrocarbyl carbamodithioate corresponds to the formula the O,O'-dithioalkylene-bis(mono- or dihydrocarbyl carbamothioate) corresponds to the formula the O,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamo-thioate) corresponds to the formula the S,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamothioate) corresponds to the formula and the S,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamo-dithioate) corresponds to the formula wherein R1 is separately in each occurrence hydrogen or C1-20 hydro-carbyl:
R2 is separately in each occurrence C1-20 hydrocarbyl;
R3 is separately in each occurrence hydrogen or C1-20 hydro-carbyl; and R4 is separately in each occurrence hydrogen or C1-20 hydro-carbyl, with the proviso that at least one R3 and R4 on the same carbon atom on each alkylene moiety must be hydrogen.
(2) adding to the above reaction solution an oxidant which is capable of oxidizing the mercapto moiety under conditions such that an O,O'- O,S'- or S,S'-dithiodialkylene-bis(mono- or dihydro-carbyl carbamothioate) or S,S'-dithiodialkylene-bis(mono- or di-hydrocarbyl carbamodithioate) is prepared;
wherein the amine corresponds to the formula NHR1R2, the 1,3-oxathiolane-2-thione corresponds to the formula the 1,3-dithiolane-2-thiones correspond to the formula the O-(2-mercaptoalkyl)mono- or dihydrocarbyl carbamothioate corresponds to the formula the S-(2-mercaptoalkyl)mono- or dihydrocarbyl carbamothioate corresponds to the formula the (2-mercaptoalkyl)mono- or dihydrocarbyl carbamodithioate corresponds to the formula the O,O'-dithioalkylene-bis(mono- or dihydrocarbyl carbamothioate) corresponds to the formula the O,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamo-thioate) corresponds to the formula the S,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamothioate) corresponds to the formula and the S,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamo-dithioate) corresponds to the formula wherein R1 is separately in each occurrence hydrogen or C1-20 hydro-carbyl:
R2 is separately in each occurrence C1-20 hydrocarbyl;
R3 is separately in each occurrence hydrogen or C1-20 hydro-carbyl; and R4 is separately in each occurrence hydrogen or C1-20 hydro-carbyl, with the proviso that at least one R3 and R4 on the same carbon atom on each alkylene moiety must be hydrogen.
11. The process of Claim 10 wherein the temperature of step (1) is -40°C to 30°C and the temperature of step (2) is -10°C to 50°C
12. The process of Claim 11 wherein the temperature of step (1) and (2) is between about 0°C and 20°C.
13. The process of Claim 10 wherein the solvent is an aroma-tic hydrocarbon, a chlorinated aliphatic hydrocarbon, a chlori-nated aromatic hydrocarbon, an aliphatic ether or a cyclic ether.
14. The process of Claim 13 wherein the solvent is an ali-phatic ether or a cyclic ether.
15. The process of Claim 14 wherein the solvent is tetra-hydrofuran.
16. The process of Claim 10 wherein the oxidant is hydrogen peroxide.
17. A process of concentrating sulfide ores by flotation, which comprises subjecting the sulfide ore in the form of a pulp, to a flotation process in the presence of a flotating amount of a flotation collector for the sulfide comprising an O,O'-, O,S'- or S,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamothioate) or S,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamodi-thioate), or mixtures thereof, which correspond to the formula wherein R1 is separately in each occurrence hydrogen or C1-20 hydro-carbyl;
R2 is separately in each occurrence C1-20 hydrocarbyl;
R3 is separately in each occurrence hydrogen or C1-20 hydro-carbyl;
R4 is separately in each occurrence hydrogen of C1-20 hydro-carbyl;
X is separately in each occurrence O or S;
Y is separately in each occurrence O or S;
with the proviso that X and Y cannot both be oxygen, and with the further proviso that at least one R3 and one R4 on the same carbon atom on each alkylene moiety must be hydrogen.
R2 is separately in each occurrence C1-20 hydrocarbyl;
R3 is separately in each occurrence hydrogen or C1-20 hydro-carbyl;
R4 is separately in each occurrence hydrogen of C1-20 hydro-carbyl;
X is separately in each occurrence O or S;
Y is separately in each occurrence O or S;
with the proviso that X and Y cannot both be oxygen, and with the further proviso that at least one R3 and one R4 on the same carbon atom on each alkylene moiety must be hydrogen.
18. The process of Claim 17 wherein the collector comprises an O,O'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamo-thioate) which corresponds to the formula or an S,S'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamodi-thioate) which corresponds to the formula or a mixture thereof wherein R1, R2, R3 and R4 are as defined in Claim 17.
19. The process of Claim 17 wherein R1 is hydrogen or C1-20 alkyl, R2 is C1-20 alkyl or phenyl, R3 is hydrogen or C1-20 alkyl, and R4 is C1-20 alkyl.
20. The process of Claim 17 wherein R1 is hydrogen, R2 is C2-10 alkyl, R3 is hydrogen or C1-4 alkyl and R4 is C1-4 alkyl.
21. The process of Claim 17 wherein 0.005 to 0.25 pound of disulfide per ton of sulfide ore pulp (0.0025 to 0.123 kg/metric ton) is employed.
22. The process of Claim 17 wherein the collector further comprises a collector selected from the group consisting of sodium xanthates, potassium xanthates, ammonium xanthates, esters of xanthic acid; sodium dithiophosphates, potassium dithiophosphates, ammonium dithiophosphates, thiocarbamate esters; sodium dithio-carbamates, potassium dithiocarbamates, ammonium dithiocarbamates, dithiocarbamate esters; mercaptobenzothiazole, sodium mercapto-benzothiazole, potassium mercaptobenzothiazole, ammonium mercapto-benzothiazole; or dixanthogens.
23. The process of Claim 17 wherein the sulfide ore is copper sulfide, zinc sulfide, molybdenum sulfide, cobalt sulfide, nickel sulfide, lead sulfide, arsenic sulfide, antimony sulfide, silver sulfide, chromium sulfide, gold sulfide, platinum sulfide and uranium sulfide.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000507447A CA1263662A (en) | 1986-04-24 | 1986-04-24 | O,o'-, o,s'-or s,s'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamothioates) and s,s'- dithiodialkylene-bis(mono- or dihydrocarbyl carbamodithioates) useful as froth flotation collectors |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000507447A CA1263662A (en) | 1986-04-24 | 1986-04-24 | O,o'-, o,s'-or s,s'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamothioates) and s,s'- dithiodialkylene-bis(mono- or dihydrocarbyl carbamodithioates) useful as froth flotation collectors |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1263662A true CA1263662A (en) | 1989-12-05 |
Family
ID=4132957
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000507447A Expired CA1263662A (en) | 1986-04-24 | 1986-04-24 | O,o'-, o,s'-or s,s'-dithiodialkylene-bis(mono- or dihydrocarbyl carbamothioates) and s,s'- dithiodialkylene-bis(mono- or dihydrocarbyl carbamodithioates) useful as froth flotation collectors |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1263662A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114682388A (en) * | 2022-03-29 | 2022-07-01 | 中国地质科学院矿产综合利用研究所 | Flotation reagent for arsenic-containing dip-dyeing type gold ore, preparation method and use method |
-
1986
- 1986-04-24 CA CA000507447A patent/CA1263662A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114682388A (en) * | 2022-03-29 | 2022-07-01 | 中国地质科学院矿产综合利用研究所 | Flotation reagent for arsenic-containing dip-dyeing type gold ore, preparation method and use method |
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