CA1070034A - Differential froth flotation of molybdenum sulfide from copper sulfide - Google Patents
Differential froth flotation of molybdenum sulfide from copper sulfideInfo
- Publication number
- CA1070034A CA1070034A CA240,550A CA240550A CA1070034A CA 1070034 A CA1070034 A CA 1070034A CA 240550 A CA240550 A CA 240550A CA 1070034 A CA1070034 A CA 1070034A
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- sulfide
- copper
- concentrate
- molybdenum
- flotation
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Abstract
ABSTRACT OF THE DISCLOSURE
An improved process of differential froth flotation applied to a flotation pulp of molybdenite and copper sulfide using only a small amount of a water-soluble ammonium, alkali metal or alkaline earth metal sulfide compound as depressant with nitrogen aeration.
An improved process of differential froth flotation applied to a flotation pulp of molybdenite and copper sulfide using only a small amount of a water-soluble ammonium, alkali metal or alkaline earth metal sulfide compound as depressant with nitrogen aeration.
Description
. 7 The Eield of art -to which the invention pertains includes the Eield of differential froth flotation, particularly with the employment of preferential modifying agents. More specifically, the field relates to the separation and recovery of molybdenum sulfide from copper ore concentrate containing both molybdenum sulfide and copper sulfide by froth flotation in the presence of a depressant for copper sulfide to effect ~ recovery of a molybdenum concentrate in the flotation overflow :~ and recovery of a copper concentrate in the flotation underflow.
1 .
¦ BACKGROUND AND 'SUMMARY OF THE IN~IENTION
Molybdenite ~MoS2) can be found in small amounts with sulfidic copper ores such as those containing chalcopyrite.
Typically, copper ores of such nature are beneficiated by , , ' ~
.
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flotation to ob-tain an ore concentrate cont:aining about 25-30%
copper and abou-t 0.3-1% molybdenum. In obtalning the concen-trate, reagents such as collectors and frot:hers are added during treatment of the ore to facilitate separati.on from the gangue materials, the molybdenite following -the copper sulEide in the flotation circuit to obtain a concentrate as above des-cribed. Thereafter, the molybdenite content of the copper ore concentrate is separated by differential flotation to obtain a molybdenum concentrate containing about 40% or more Mo. In view of the fact tha-t sulfidic copper minerals and molybdenite are floated by the same collectors, in order to effect a differential flotation of the molybdenite it has .
been found.necessary to depress.the copper sulfide while floating the molybdenite content of the concentrate. The use of sulfides with or wi-thout a collector for the molyb- ~ .
denum sulfide has been known and used in the industry for many years. However, in the last 25 years a process widely used in industry for differential flotation of molybdenite has included conditioning an aqueous pulp of the molybdenite- -containing copper ore concentrate with a material known as a "Nokes-type" reagent for depressing the copper sulfide and with a conventional collector for molybdenum sulfide.
The conditioned pulp is then subjected to froth flotation with a conventional fl.otation machine to obtain a molybdenum concentrate as -the flotation overflow and a copper concentrate tailing as the flotation underflow.
Nokes-type reagents are complex sulfur compounds of phosphorus, arsenic or antimony and a caustic. See, in ~C~7~
this regard, Nokes et al U.S~ Patent No. 2,492,936. They are substantially more expensive than simpler sulfides, Eor example, sodium hydrosulfide, cos-ting at present about 1.5 times as much as such simple sulfides, but their effective-ness is such that substantially less Nokes-type reagent need be used than the simple sulfide with the result that the Nokes-type depressants have become a standard in the industry.
Although Nokes-type depressants are used at lower levels than the simple sulfides, their cost and constant consumption adds significantly to the cost of the molybdenum ultimately produced. An attempt to mitigate such costs can be found in Delaney U.S. Patent No. 3,655,044 wherein a process is described in which the amount of Nokes-type reagent required as a depressant is reduced so that only about one-fifth to one-half of the usual amount is needed.
The process requires the addition of a collector for the molybdenum sulfide along with the use of an inert gas, such as nitrogen, as the froth producing gas. While ordinary collectors are not a major cost item, the use of nitrogen is sufficiently costly so that the aforenoted xeduction in the concentration of Nokes reagent cannot readily justify nitrogen aeration, particularly when one considers that an increased capital investment may be required.
The present invention provides a process for froth flotation of molybdenum sulfide which also employs nitrogen as the aerating gas but which is economically ~07~3~
l operational hecal1se it (a) uses a clepressant reagent for
1 .
¦ BACKGROUND AND 'SUMMARY OF THE IN~IENTION
Molybdenite ~MoS2) can be found in small amounts with sulfidic copper ores such as those containing chalcopyrite.
Typically, copper ores of such nature are beneficiated by , , ' ~
.
. ., . :, . ~, .' ~ . '. ,-,'~ .
.. .~ .
. ~ . . ~.I
- I .
- ~. . ..
:
, ~'7C3 ~3~
flotation to ob-tain an ore concentrate cont:aining about 25-30%
copper and abou-t 0.3-1% molybdenum. In obtalning the concen-trate, reagents such as collectors and frot:hers are added during treatment of the ore to facilitate separati.on from the gangue materials, the molybdenite following -the copper sulEide in the flotation circuit to obtain a concentrate as above des-cribed. Thereafter, the molybdenite content of the copper ore concentrate is separated by differential flotation to obtain a molybdenum concentrate containing about 40% or more Mo. In view of the fact tha-t sulfidic copper minerals and molybdenite are floated by the same collectors, in order to effect a differential flotation of the molybdenite it has .
been found.necessary to depress.the copper sulfide while floating the molybdenite content of the concentrate. The use of sulfides with or wi-thout a collector for the molyb- ~ .
denum sulfide has been known and used in the industry for many years. However, in the last 25 years a process widely used in industry for differential flotation of molybdenite has included conditioning an aqueous pulp of the molybdenite- -containing copper ore concentrate with a material known as a "Nokes-type" reagent for depressing the copper sulfide and with a conventional collector for molybdenum sulfide.
The conditioned pulp is then subjected to froth flotation with a conventional fl.otation machine to obtain a molybdenum concentrate as -the flotation overflow and a copper concentrate tailing as the flotation underflow.
Nokes-type reagents are complex sulfur compounds of phosphorus, arsenic or antimony and a caustic. See, in ~C~7~
this regard, Nokes et al U.S~ Patent No. 2,492,936. They are substantially more expensive than simpler sulfides, Eor example, sodium hydrosulfide, cos-ting at present about 1.5 times as much as such simple sulfides, but their effective-ness is such that substantially less Nokes-type reagent need be used than the simple sulfide with the result that the Nokes-type depressants have become a standard in the industry.
Although Nokes-type depressants are used at lower levels than the simple sulfides, their cost and constant consumption adds significantly to the cost of the molybdenum ultimately produced. An attempt to mitigate such costs can be found in Delaney U.S. Patent No. 3,655,044 wherein a process is described in which the amount of Nokes-type reagent required as a depressant is reduced so that only about one-fifth to one-half of the usual amount is needed.
The process requires the addition of a collector for the molybdenum sulfide along with the use of an inert gas, such as nitrogen, as the froth producing gas. While ordinary collectors are not a major cost item, the use of nitrogen is sufficiently costly so that the aforenoted xeduction in the concentration of Nokes reagent cannot readily justify nitrogen aeration, particularly when one considers that an increased capital investment may be required.
The present invention provides a process for froth flotation of molybdenum sulfide which also employs nitrogen as the aerating gas but which is economically ~07~3~
l operational hecal1se it (a) uses a clepressant reagent for
2 the copper sulEide which is substanti.ally less costly than
3 the Nokes-type reagen-t, (b) surprisingly operates with an
4 amount of depressant reagent which can be as little as 51 l/20 or less of -the amount of depresc,ant usually required 6 in -the absence oE nitrogen aeration, and (c) can often 71 operate without the further addition of a collec-tor for 81 the molybdenite. r lO¦ i~lore particularly, an aqueous pulp of copper ll¦ ` concentrate containing both molybdenum sulfide and copper l2¦ sulfide is conditioned with a depressant comprising, as l3¦ its major constituent, a water-soluble ammonium, alkali l4¦ metal or alkaline earth metal sulfide and the conditioned l5¦ pulp is subjected to froth flotation in which an inert ~61 gas comprising nitrogen as its major component is employed 17¦ as the froth producing medium. A molybdenum concentrate 18 ¦ is recovered in the flota-tion overflow and a copper con-l9 ¦ centrate i5 recovered in the flotation underflow wi-thout 20 ¦ the occurrence of substantial oxidation in the conditioned 21 ¦ aqueous pulp.
23 ¦ The present process is par-ticularly suitable 241 for continuous operation wherein the sulfide concentration 251 oE the copper ore concentrate pulp is measured on a con-26 tinuous basis and the above sulfide depressant is added 27 in an amount suEficient to maintain the measured sulfide 28 concentration above a predetermined value sufficient to 29 effectively depress the copper sulfide. In accordance with the present invention, a sulEide concentration as 31 ___ 32 ___ ~37~3~ `
little as 0.1 pounds per ton of concentrate can he used to e~fect satisfactory separation of the molybdenite.
The present in~entlon, therefore, provides a process (and preferably a continuous process) for the separation and recovery of molybdenum sulfide fr copper ore concentrate containing both molybdenum sul~ide and copper sulfide which comprises conditioning an aqueous pulp of the copper ore concentrate with a depressant or said copper sulfide comprising as the major depressa~t constituent 0~1 lb lb to 3.0 lbs. per ton of said concentrate of a water-soluble am~tonium, alkali metal or alkaline earth metal sulfide, and subjecting the conditioned pulp to froth flotation in which an inert gas comprising nitrogen as its major component is ~tployed as the froth producing medium to effect recovery of a molybdenum con~entrate ir.t the flotation overflow and recoYery of a copper con.centrate i~ the flotation underflow with~ut the occurrence of su~stantial oxidation in the conditioned aqueous pulp.
., . . : ., .. ~ , . .. ........ ... . . .. ....
BRIEF DESCRIPTION OF T~E DRAl~INGS
.FIGURE 1 is a graph showing the chanye in sulfide concentrations at different initial levels, measured by means of an electrode with respect to time when the pulp is aerated with air and with nitxogen; and FIGURE 2 is a.graph which illustrates the rela-` tionship between the percentage o~ molybdenite recovered, copper sulfide recovered and sul~id~ concentration, t~ith respect to time when the pulp is.~erated with air in one example and with nitr~gen ir.t another example.
3~
DETAILED_DESCRIPTION
As above-described, conventional ore benePiciation operations on sul~idic copper ores, such as chalcopyrite r can result in the preparation o~ a copper ore concentrate that typically contalns up to about 30 plercen-t by weight copper and up to about 1 percent by weight molybdenumO In accordance with the present invention, molybdenite is, separat~d from the coppex sulfide concantrate by the ~ddi-tion of a s~lfide depressant for th~ copper sulfide and froth flotation by aeration wi~h nitroyen. ~ ~ollect:or or the moly~denite need not ~e added, but is not pr~cluded,and, for parti~ular ores, i~ may be desirable. In su~h case, any conventional.colle~t~r can be usPd t such as potassium xanthat~, fuel oil, or sodi~m di-sec-butyl~
thiophospha.te~ Add~tionally~ any ~on~en~ional froth~r
23 ¦ The present process is par-ticularly suitable 241 for continuous operation wherein the sulfide concentration 251 oE the copper ore concentrate pulp is measured on a con-26 tinuous basis and the above sulfide depressant is added 27 in an amount suEficient to maintain the measured sulfide 28 concentration above a predetermined value sufficient to 29 effectively depress the copper sulfide. In accordance with the present invention, a sulEide concentration as 31 ___ 32 ___ ~37~3~ `
little as 0.1 pounds per ton of concentrate can he used to e~fect satisfactory separation of the molybdenite.
The present in~entlon, therefore, provides a process (and preferably a continuous process) for the separation and recovery of molybdenum sulfide fr copper ore concentrate containing both molybdenum sul~ide and copper sulfide which comprises conditioning an aqueous pulp of the copper ore concentrate with a depressant or said copper sulfide comprising as the major depressa~t constituent 0~1 lb lb to 3.0 lbs. per ton of said concentrate of a water-soluble am~tonium, alkali metal or alkaline earth metal sulfide, and subjecting the conditioned pulp to froth flotation in which an inert gas comprising nitrogen as its major component is ~tployed as the froth producing medium to effect recovery of a molybdenum con~entrate ir.t the flotation overflow and recoYery of a copper con.centrate i~ the flotation underflow with~ut the occurrence of su~stantial oxidation in the conditioned aqueous pulp.
., . . : ., .. ~ , . .. ........ ... . . .. ....
BRIEF DESCRIPTION OF T~E DRAl~INGS
.FIGURE 1 is a graph showing the chanye in sulfide concentrations at different initial levels, measured by means of an electrode with respect to time when the pulp is aerated with air and with nitxogen; and FIGURE 2 is a.graph which illustrates the rela-` tionship between the percentage o~ molybdenite recovered, copper sulfide recovered and sul~id~ concentration, t~ith respect to time when the pulp is.~erated with air in one example and with nitr~gen ir.t another example.
3~
DETAILED_DESCRIPTION
As above-described, conventional ore benePiciation operations on sul~idic copper ores, such as chalcopyrite r can result in the preparation o~ a copper ore concentrate that typically contalns up to about 30 plercen-t by weight copper and up to about 1 percent by weight molybdenumO In accordance with the present invention, molybdenite is, separat~d from the coppex sulfide concantrate by the ~ddi-tion of a s~lfide depressant for th~ copper sulfide and froth flotation by aeration wi~h nitroyen. ~ ~ollect:or or the moly~denite need not ~e added, but is not pr~cluded,and, for parti~ular ores, i~ may be desirable. In su~h case, any conventional.colle~t~r can be usPd t such as potassium xanthat~, fuel oil, or sodi~m di-sec-butyl~
thiophospha.te~ Add~tionally~ any ~on~en~ional froth~r
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can be added such as pine oil or methyl isobutyl carbinol (MIBC) and a commercial form of MIBC as sold by -the Shell Oil. Co. under ~he designation 1638, comprising 90% MIBC
and 10~ still bot-toms. As a resul-t of the copper circuit, the pulp is at a pH level of about 11~12 03^ higher.
The copper sulfide depressan-t comprises as the ma~or depressant constituent a water-solub~Le ammonium, alkali metal or alkaline earth metal sulfide. The term sulfide is meant to include monosulfides, polysulfides, hydrosulfides and hydrated forms. Specific examples of the sulfide com-pounds include ammonium sulfide, ammonium hydrosulfide, lithium sulfide, lithium hydrosulfide, sodium monosulfide, sodi~lm hydrosulfide, potassium monosulfide, potassium hydrosulfide, rubidium monosulfide, cesium monosulfide, calcium hydro-sulfide, strontium hydrosulfide, barium hydrosulfide, water-soluble polysulfide forms thereof, hydrated forms thereof, and mixtures thereof. It is an important and surprising result of the present invention that the foregoing sulfides, most of which are readily and economically available, can be used in the present process in place of a Nokes reagent at levels which are only a fraction of the amount normally required of such suIfides. Thus, while the usual total amount (rougher and cleaner operations) of sodium hydro-sulfide required for effective molybdenite separation is about 10-25 pounds per ton (PPT), a satisfactory separation can be obtained with the present process by the typical use of 0.5--1 PPT and as little as 0.1 PPT of the sulfide. A sat-isfactory range, depending on the source of ore, is about 0.1-3 PPT. Accordingly, as little as 1/20 or less of the normal amount of sulfide is required. Par-ticularly prefexred, enconornically ~O~ 3~
optimal sulfides are sodium sulfide, sodium hydrosulfide~
ammonium sulfide, ammonium hydrosulfide ancl mi~tures -thereof.
The froth flo-tation is carried out in conventional agitator-equipped flotation cells which otherwise use air as the froth producing gas. In the present inventionl nitrogen is used in place of air; more broadly, an inert gas is used which comprises nitrogen as its ma~or com-ponent.
Electrode determination of the concentration of sulfide in the pulp can be used as a measure of whether copper sulfide is being effectively depressed.
Such electrodes are commercially available and can be exemplified by the "Orion"* Research Model 9~-16 electrode (Orion Research Incoporated~ Cambridge, ~assachusetts) which is specific for silver ion and for sulfide ion activity. The electrodes are periodically standardized using 0.10 molar sodium sulfide solution. An amplified millivolt signal is plo-tted automatically on a strip chart and represents the sulfide concentration. Any abrupt change in slope of the sulfide content, as measured on the strip chartl indicates a drop-off in depressant concentration. Referring to Figure 1, there is plotted the concentration of sulfide as indicated by millivolt reading from an "Orion" Research electrode in various pulp slurries. When 6.0 PPT, of sodium hydrogen sulfide is added to a copper sulfide concentrate pulp, and air is used for the ~roth flota*ion, there is a rapid drop in *Trademark ~L~17~3~
1 sul:Eide concentration, as indicated by the line 10. After 2 3-~1 minutes, the amount o:E sul:Eide concen~ration :is so 3 low tha-t an inordina-te amount of copper sulfide floats with the molybdenum sulfide. When ni-t:rogen is substituted .~or air -there is virtually no drop in sul:Eide concentration
~ -- \
~7~
can be added such as pine oil or methyl isobutyl carbinol (MIBC) and a commercial form of MIBC as sold by -the Shell Oil. Co. under ~he designation 1638, comprising 90% MIBC
and 10~ still bot-toms. As a resul-t of the copper circuit, the pulp is at a pH level of about 11~12 03^ higher.
The copper sulfide depressan-t comprises as the ma~or depressant constituent a water-solub~Le ammonium, alkali metal or alkaline earth metal sulfide. The term sulfide is meant to include monosulfides, polysulfides, hydrosulfides and hydrated forms. Specific examples of the sulfide com-pounds include ammonium sulfide, ammonium hydrosulfide, lithium sulfide, lithium hydrosulfide, sodium monosulfide, sodi~lm hydrosulfide, potassium monosulfide, potassium hydrosulfide, rubidium monosulfide, cesium monosulfide, calcium hydro-sulfide, strontium hydrosulfide, barium hydrosulfide, water-soluble polysulfide forms thereof, hydrated forms thereof, and mixtures thereof. It is an important and surprising result of the present invention that the foregoing sulfides, most of which are readily and economically available, can be used in the present process in place of a Nokes reagent at levels which are only a fraction of the amount normally required of such suIfides. Thus, while the usual total amount (rougher and cleaner operations) of sodium hydro-sulfide required for effective molybdenite separation is about 10-25 pounds per ton (PPT), a satisfactory separation can be obtained with the present process by the typical use of 0.5--1 PPT and as little as 0.1 PPT of the sulfide. A sat-isfactory range, depending on the source of ore, is about 0.1-3 PPT. Accordingly, as little as 1/20 or less of the normal amount of sulfide is required. Par-ticularly prefexred, enconornically ~O~ 3~
optimal sulfides are sodium sulfide, sodium hydrosulfide~
ammonium sulfide, ammonium hydrosulfide ancl mi~tures -thereof.
The froth flo-tation is carried out in conventional agitator-equipped flotation cells which otherwise use air as the froth producing gas. In the present inventionl nitrogen is used in place of air; more broadly, an inert gas is used which comprises nitrogen as its ma~or com-ponent.
Electrode determination of the concentration of sulfide in the pulp can be used as a measure of whether copper sulfide is being effectively depressed.
Such electrodes are commercially available and can be exemplified by the "Orion"* Research Model 9~-16 electrode (Orion Research Incoporated~ Cambridge, ~assachusetts) which is specific for silver ion and for sulfide ion activity. The electrodes are periodically standardized using 0.10 molar sodium sulfide solution. An amplified millivolt signal is plo-tted automatically on a strip chart and represents the sulfide concentration. Any abrupt change in slope of the sulfide content, as measured on the strip chartl indicates a drop-off in depressant concentration. Referring to Figure 1, there is plotted the concentration of sulfide as indicated by millivolt reading from an "Orion" Research electrode in various pulp slurries. When 6.0 PPT, of sodium hydrogen sulfide is added to a copper sulfide concentrate pulp, and air is used for the ~roth flota*ion, there is a rapid drop in *Trademark ~L~17~3~
1 sul:Eide concentration, as indicated by the line 10. After 2 3-~1 minutes, the amount o:E sul:Eide concen~ration :is so 3 low tha-t an inordina-te amount of copper sulfide floats with the molybdenum sulfide. When ni-t:rogen is substituted .~or air -there is virtually no drop in sul:Eide concentration
6 over the ~ull 10 minutes oE flota-tion, as indicated by the
7 line 12. ~s shown by the line 14, when the amount of sodium
8 hydrogen sulfide is reduced -to 1/10 o~ -the above amount,
9¦ i.e., 0.6 PPT, the initial concentra-tion of khe sulEide is,
10 ¦ of course, lower and there is some drop with time, but, lI ¦ importantly, the level is main-tained at a sufficient con-12 ¦ centra-tion to prevent inordinate copper floating.
13 I .
1~ I In a further embodiment, the present invention 15 ¦ is particularly suitable fo~ a continuous process in which 1~ ¦ concentrate pulp is fed on a continuous basis -to a bank 17 ¦ of serially disposed froth flotation cells. The floated 18 ¦ froth, i.e., the molybdenum rougher concen-trate,can be 19 reslurried for one or more successive operations and sul~ide depressant is pre~erably added as needed to each 21 cleaner bank of cells. In accordance with this embodiment, 22 the quantity of reagent used is regulated by the concen-23 tration of sulfide ion which is measured on a continuous 2~ basis as an amplified millivolt signal given by an elec-trode,as above described. The phrase "continuous basis"
26 is meant to include measurements which are either contin-27 uous without interrupti.on or are periodic. While it is 28 preferred ko measure the sulfide concentration without 29 interruption, periodic measurements are satisfactory i~
the intervals are short enough so that quality control can 31 ___ .
3~
be maintained. By continuous moni-toring of -the sul~ide con-tent and adjustment there-to to the leveL deslred, e.g.
0.1 PPT oE NaHS, a minimum amount of sul~ide can be used to obtain a satisfactory depression of the copper sulEide.
Taken together with the lower sulfide addition permitted by the us-e of nitrogen as the aerating gas, the total savings are quite substantial.
In order that those skilled in -the art may better understand how the present invention may be prac--ticed, the following Examples are given by way of illus-tration and without limitation.
EXAl~PLE I
A pulp charge of 1343 grams of copper sulfide concentrate obtained from rougher and cleaning flo~tation of Pima Arizona chalcopyrite, and containing 24.3% copper and 1.0% molybdenum, was added to a standard laboratory flotation machine, sold under the trade mark "Agitair", and diluted with 4 liters of water. Sufficient sodium hydrosulfide was added to obtain a concentration of 8 pounds of the sulfide per ton o~ the concentrate. The sulfide ion concen-tration was monitored with an "Orion"
Research Sulfide Ion electrode. The pulp was allowed to condition until stable sulfide ion readings were obtained on a strip chart. At that point, air was injected and flotation carried out for a period of 16 minutes. During the flotation, the voltage output from the sulfide ion electrode was continuously recorded on a strip chart g _ ~7~
recorder. The flotation ovexflow, i.e., the froth, was collec-ted at 2 minutes intervals, the mineral con-tent thereof was welghed and the copper and molybdenum con--tent were assayed. At the conclusion of the run, -the flotation underflow was collected, the mineral content thereof was weighed and -the copper and molybdenum con-tent were assayed. The results are set forth in Table I.
TABLE I
Time,Wt. mineral Assay Cum. weight Recovered Min Rec.% Cu % Mo Cu Mo % ~u % Mb 2 60.710.26 16.74 6.23 10.161.91 74.59 4 23.9 16.56 7.83 10.18 12.03 3.12 88.32 6 18.7 22.25 3.50 14.34 12.68 4.39 93.09 8 19.1 25.40 1.11 19.19 12.89 5.88 94.63 30.0 25.91 0.555 26.97 13.06 8.27 95.88 12 147.5 31.90 0.182 74.0 13.33 22.7 97.85 14 196.9 30.99 0.047 135 13.42 41.41 98.52 16 181.3 29.01 0.023 188 13.47 57.67 98.89 tails 665 20.73 0.023 326 13.62 :
EXAMPLE II
The procedure of Example I was fo]lowed in all details except that sodium hydrosul~ide was used in a con-centration ofl PPT and pure nitrogen was used in place of air as the aeration gas. The pulp charge was 1353 grams of -copper sulfide concentrate containing 25.0% copper and 0.97% ~
. .
39~
molybdenum. Measurements, weighings and assays were conducted as in Example I. The resulLs are set Eorth in Table II~
TABLE II
Time; Wt. mineral Assay ~lm. weight Recovered Min. Rec. % Cu ~ MD Cu Mo % Cu %Mo 2 62.~ 27.94 16.47 17.~3 10.27 5.15 78O0 4 19.6 13.51 7.94 20.08 11.83 5.92 90.0 6 15.4 19.00 2.956 23.01 12.29 6.8 93.
8 14.5 23.52 2.120 26.41 12.59 7.8 95.5 15.4 26.11 1.229 30.43 12.78 9.0 97.0 12 14.8 26.62 0.792 34.38 12.90 10.1 98.5 14 10.4 26.62 0.582 37.15 12.96 10.8 98.6 16 11.3 26.62 0.419 40.15 13.01 11.8 98.8 tails 1189 25.10 0.014 338.5 13.18 A comparison of the results in Tables I and II reveals that not only was a greater percentage of molybdenum recovered in a shorter period oE -time but containing very much less copper, all with the use of, in this case, 1/8 the amount of sodium hydrosulfide.
Referring to Figure 2, the results listed in Tables I and II are shown graphically along with the sulfide ion concentration as represented ~y the millivolt reading from an '!Orion" Research electrode in each case. The solid line indicates the values pertinent to the first Example and -the dashed line indicates the values pertinent to the second Example. It can be seen that a slight benefit was obtained in -terms of molybdenum recovery and that a tremendous benefit -was obtained with respect to the continued dep:ression of copper sulfide.
E~AMPLES III-XIV
The procedure of Example II can he followed except that in twelve separate runs, 1 PPT of ammonium sulfide, ammonium hydrosulfide, lithium sul.-fide/ lithium hydrosulfide, sodium monosulfide, potassium monosulfide, potassium hydrosulfide, rubidium monosulfide, cesium monosulfide, calcium hydrosulfide, strontium hydrosulfide and barium hydrosulfide, respectively, are substituted :
for the sodium hydrosulfide.
It should be understood that while the present invention has been described in considerable detail with respect to certain specific embodiments thereof, it is not to be considered limited to those embodiments, but may be used in other ways which do not depart from the spirit of the invention or the scope of the appended claims.
~ 12
13 I .
1~ I In a further embodiment, the present invention 15 ¦ is particularly suitable fo~ a continuous process in which 1~ ¦ concentrate pulp is fed on a continuous basis -to a bank 17 ¦ of serially disposed froth flotation cells. The floated 18 ¦ froth, i.e., the molybdenum rougher concen-trate,can be 19 reslurried for one or more successive operations and sul~ide depressant is pre~erably added as needed to each 21 cleaner bank of cells. In accordance with this embodiment, 22 the quantity of reagent used is regulated by the concen-23 tration of sulfide ion which is measured on a continuous 2~ basis as an amplified millivolt signal given by an elec-trode,as above described. The phrase "continuous basis"
26 is meant to include measurements which are either contin-27 uous without interrupti.on or are periodic. While it is 28 preferred ko measure the sulfide concentration without 29 interruption, periodic measurements are satisfactory i~
the intervals are short enough so that quality control can 31 ___ .
3~
be maintained. By continuous moni-toring of -the sul~ide con-tent and adjustment there-to to the leveL deslred, e.g.
0.1 PPT oE NaHS, a minimum amount of sul~ide can be used to obtain a satisfactory depression of the copper sulEide.
Taken together with the lower sulfide addition permitted by the us-e of nitrogen as the aerating gas, the total savings are quite substantial.
In order that those skilled in -the art may better understand how the present invention may be prac--ticed, the following Examples are given by way of illus-tration and without limitation.
EXAl~PLE I
A pulp charge of 1343 grams of copper sulfide concentrate obtained from rougher and cleaning flo~tation of Pima Arizona chalcopyrite, and containing 24.3% copper and 1.0% molybdenum, was added to a standard laboratory flotation machine, sold under the trade mark "Agitair", and diluted with 4 liters of water. Sufficient sodium hydrosulfide was added to obtain a concentration of 8 pounds of the sulfide per ton o~ the concentrate. The sulfide ion concen-tration was monitored with an "Orion"
Research Sulfide Ion electrode. The pulp was allowed to condition until stable sulfide ion readings were obtained on a strip chart. At that point, air was injected and flotation carried out for a period of 16 minutes. During the flotation, the voltage output from the sulfide ion electrode was continuously recorded on a strip chart g _ ~7~
recorder. The flotation ovexflow, i.e., the froth, was collec-ted at 2 minutes intervals, the mineral con-tent thereof was welghed and the copper and molybdenum con--tent were assayed. At the conclusion of the run, -the flotation underflow was collected, the mineral content thereof was weighed and -the copper and molybdenum con-tent were assayed. The results are set forth in Table I.
TABLE I
Time,Wt. mineral Assay Cum. weight Recovered Min Rec.% Cu % Mo Cu Mo % ~u % Mb 2 60.710.26 16.74 6.23 10.161.91 74.59 4 23.9 16.56 7.83 10.18 12.03 3.12 88.32 6 18.7 22.25 3.50 14.34 12.68 4.39 93.09 8 19.1 25.40 1.11 19.19 12.89 5.88 94.63 30.0 25.91 0.555 26.97 13.06 8.27 95.88 12 147.5 31.90 0.182 74.0 13.33 22.7 97.85 14 196.9 30.99 0.047 135 13.42 41.41 98.52 16 181.3 29.01 0.023 188 13.47 57.67 98.89 tails 665 20.73 0.023 326 13.62 :
EXAMPLE II
The procedure of Example I was fo]lowed in all details except that sodium hydrosul~ide was used in a con-centration ofl PPT and pure nitrogen was used in place of air as the aeration gas. The pulp charge was 1353 grams of -copper sulfide concentrate containing 25.0% copper and 0.97% ~
. .
39~
molybdenum. Measurements, weighings and assays were conducted as in Example I. The resulLs are set Eorth in Table II~
TABLE II
Time; Wt. mineral Assay ~lm. weight Recovered Min. Rec. % Cu ~ MD Cu Mo % Cu %Mo 2 62.~ 27.94 16.47 17.~3 10.27 5.15 78O0 4 19.6 13.51 7.94 20.08 11.83 5.92 90.0 6 15.4 19.00 2.956 23.01 12.29 6.8 93.
8 14.5 23.52 2.120 26.41 12.59 7.8 95.5 15.4 26.11 1.229 30.43 12.78 9.0 97.0 12 14.8 26.62 0.792 34.38 12.90 10.1 98.5 14 10.4 26.62 0.582 37.15 12.96 10.8 98.6 16 11.3 26.62 0.419 40.15 13.01 11.8 98.8 tails 1189 25.10 0.014 338.5 13.18 A comparison of the results in Tables I and II reveals that not only was a greater percentage of molybdenum recovered in a shorter period oE -time but containing very much less copper, all with the use of, in this case, 1/8 the amount of sodium hydrosulfide.
Referring to Figure 2, the results listed in Tables I and II are shown graphically along with the sulfide ion concentration as represented ~y the millivolt reading from an '!Orion" Research electrode in each case. The solid line indicates the values pertinent to the first Example and -the dashed line indicates the values pertinent to the second Example. It can be seen that a slight benefit was obtained in -terms of molybdenum recovery and that a tremendous benefit -was obtained with respect to the continued dep:ression of copper sulfide.
E~AMPLES III-XIV
The procedure of Example II can he followed except that in twelve separate runs, 1 PPT of ammonium sulfide, ammonium hydrosulfide, lithium sul.-fide/ lithium hydrosulfide, sodium monosulfide, potassium monosulfide, potassium hydrosulfide, rubidium monosulfide, cesium monosulfide, calcium hydrosulfide, strontium hydrosulfide and barium hydrosulfide, respectively, are substituted :
for the sodium hydrosulfide.
It should be understood that while the present invention has been described in considerable detail with respect to certain specific embodiments thereof, it is not to be considered limited to those embodiments, but may be used in other ways which do not depart from the spirit of the invention or the scope of the appended claims.
~ 12
Claims (8)
1. A process for the separation and recovery of molybdenum sulfide from copper ore concentrate containing both molybdenum sulfide and copper sulfide which comprises conditioning an aqueous pulp of the copper ore concentrate with a depressant for said copper sulfide comprising as the major depressant constituent 0.1 lb lb to 3.0 lbs. per ton of said concentrate of a water-soluble ammonium, alkali metal or alkaline earth metal sulfide, and subjecting the conditioned pulp to froth flotation in which an inert gas comprising nitrogen as its major component is employed as the froth producing medium to effect recovery of a molybdenum concentrate in the flotation overflow and recovery of a copper concentrate in the flotation underflow without the occurrence of substantial oxidation in the conditioned aqueous pulp.
2. The process according to Claim 1 in which said non-oxidizing aerating gas consists essentially of nitrogen.
3. The process according to Claim 1 in which said sulfide is selected from the group consisting essentially of sodium sulfide, sodium hydrosulfide, ammonium sulfide, ammonium hydrosulfide, and mixtures thereof.
4. The process according to Claim 1 in which said water soluble depressant consists essentially of said sulfide.
5. A continuous process for the separation and recovery of molybdenum sulfide from copper ore concentrate containing both molybdenum sulfide and copper sulfide, which comprises measuring on a continuous basis the sulfide concen-tration of an aqueous pulp of the copper ore concentrate, adding to said aqueous pulp a depressant for said copper sulfide comprising as the major depressant constituent 0.1 to 3.0 lbs per ton of said concentrate of a water-soluble ammonium, alkali metal or alkaline earth metal sulfide and subjecting the conditioned pulp to froth flotation in which an inert gas comprising nitrogen as its major component is employed as the froth producing medium to effect recovery of a molybdenum concentrate in the flotation overflow and recovery of a copper concentrate in the flotation underflow without the occurrence of substantial oxidation in the conditioned aqueous pulp.
6. The process according to Claim 5 in which said non-oxidizing aerating gas consists essentially of nitrogen.
7. The process according to Claim 5 in which said sulfide is selected from the group consisting essentially of sodium sulfide, sodium hydrosulfide, ammonium sulfide, ammonium hydrosulfide, and mixtures thereof.
8. The process according to Claim 5 in which said water soluble depressant consists essentially of said sulfide.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US58423075A | 1975-06-05 | 1975-06-05 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1070034A true CA1070034A (en) | 1980-01-15 |
Family
ID=24336464
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA240,550A Expired CA1070034A (en) | 1975-06-05 | 1975-11-26 | Differential froth flotation of molybdenum sulfide from copper sulfide |
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| CA (1) | CA1070034A (en) |
Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4425230A (en) | 1982-02-16 | 1984-01-10 | Oreprep Chemicals, Inc. | Separation of molybdenite from its mixture with other sulfide ores |
| US4549959A (en) * | 1984-10-01 | 1985-10-29 | Atlantic Richfield Company | Process for separating molybdenite from a molybdenite-containing copper sulfide concentrate |
| US4575419A (en) * | 1984-07-16 | 1986-03-11 | Occidental Chemical Corporation | Differential flotation reagent for molybdenum separation |
| US4650569A (en) * | 1983-03-18 | 1987-03-17 | South American Placers, Inc. | Process for the selective separation of base metal sulfides and oxides contained in an ore |
| US4657669A (en) * | 1982-06-17 | 1987-04-14 | Sentrachem Limited | Depressants for froth flotation |
| US5753104A (en) * | 1994-07-06 | 1998-05-19 | Boc Gases Australia Limited | Physical separation processes for mineral slurries |
| US5855770A (en) * | 1994-11-25 | 1999-01-05 | Boc Gases Australia Limited | Base metal mineral flotation processes |
| US6036025A (en) * | 1997-03-26 | 2000-03-14 | Boc Gases Australia Limited | Mineral flotation separation by deoxygenating slurries and mineral surfaces |
| US6427843B1 (en) * | 1998-05-27 | 2002-08-06 | Boc Gases Australia Ltd. | Flotation separation of valuable minerals |
| US6679383B2 (en) * | 2001-11-21 | 2004-01-20 | Newmont Usa Limited | Flotation of platinum group metal ore materials |
| US7219804B2 (en) | 2003-08-26 | 2007-05-22 | Newmont Usa Limited | Flotation processing including recovery of soluble nonferrous base metal values |
| US8413816B2 (en) | 2010-02-16 | 2013-04-09 | Nalco Company | Sulfide flotation aid |
| WO2015157498A1 (en) * | 2014-04-11 | 2015-10-15 | Tessenderlo Kerley, Inc. | Depression of copper and iron sulfides in molybdenite flotation circuits |
| CN106694236A (en) * | 2016-12-07 | 2017-05-24 | 广西大学 | Preparation method of ferromolybdenum ore collecting agent |
-
1975
- 1975-11-26 CA CA240,550A patent/CA1070034A/en not_active Expired
Cited By (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4425230A (en) | 1982-02-16 | 1984-01-10 | Oreprep Chemicals, Inc. | Separation of molybdenite from its mixture with other sulfide ores |
| US4657669A (en) * | 1982-06-17 | 1987-04-14 | Sentrachem Limited | Depressants for froth flotation |
| US4650569A (en) * | 1983-03-18 | 1987-03-17 | South American Placers, Inc. | Process for the selective separation of base metal sulfides and oxides contained in an ore |
| US4575419A (en) * | 1984-07-16 | 1986-03-11 | Occidental Chemical Corporation | Differential flotation reagent for molybdenum separation |
| US4549959A (en) * | 1984-10-01 | 1985-10-29 | Atlantic Richfield Company | Process for separating molybdenite from a molybdenite-containing copper sulfide concentrate |
| US5753104A (en) * | 1994-07-06 | 1998-05-19 | Boc Gases Australia Limited | Physical separation processes for mineral slurries |
| US5855770A (en) * | 1994-11-25 | 1999-01-05 | Boc Gases Australia Limited | Base metal mineral flotation processes |
| US6036025A (en) * | 1997-03-26 | 2000-03-14 | Boc Gases Australia Limited | Mineral flotation separation by deoxygenating slurries and mineral surfaces |
| US6427843B1 (en) * | 1998-05-27 | 2002-08-06 | Boc Gases Australia Ltd. | Flotation separation of valuable minerals |
| US6679383B2 (en) * | 2001-11-21 | 2004-01-20 | Newmont Usa Limited | Flotation of platinum group metal ore materials |
| US7219804B2 (en) | 2003-08-26 | 2007-05-22 | Newmont Usa Limited | Flotation processing including recovery of soluble nonferrous base metal values |
| US8413816B2 (en) | 2010-02-16 | 2013-04-09 | Nalco Company | Sulfide flotation aid |
| WO2015157498A1 (en) * | 2014-04-11 | 2015-10-15 | Tessenderlo Kerley, Inc. | Depression of copper and iron sulfides in molybdenite flotation circuits |
| US10717090B2 (en) | 2014-04-11 | 2020-07-21 | Tessenderlo Kerley, Inc. | Depression of copper and iron sulfides in molybdenite flotation circuits |
| CN106694236A (en) * | 2016-12-07 | 2017-05-24 | 广西大学 | Preparation method of ferromolybdenum ore collecting agent |
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