CA1238430A - Flotation separation of pentlandite from pyrrhotite using sulfur dioxide-air conditioning - Google Patents
Flotation separation of pentlandite from pyrrhotite using sulfur dioxide-air conditioningInfo
- Publication number
- CA1238430A CA1238430A CA000470472A CA470472A CA1238430A CA 1238430 A CA1238430 A CA 1238430A CA 000470472 A CA000470472 A CA 000470472A CA 470472 A CA470472 A CA 470472A CA 1238430 A CA1238430 A CA 1238430A
- Authority
- CA
- Canada
- Prior art keywords
- slurry
- process according
- pyrrhotite
- ore
- sulfur dioxide
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 229910052952 pyrrhotite Inorganic materials 0.000 title claims abstract description 54
- 238000005188 flotation Methods 0.000 title claims abstract description 31
- 229910052954 pentlandite Inorganic materials 0.000 title claims abstract description 30
- 238000000926 separation method Methods 0.000 title abstract description 24
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 title abstract description 6
- 229910052717 sulfur Inorganic materials 0.000 title abstract description 6
- 239000011593 sulfur Substances 0.000 title abstract description 6
- 238000004378 air conditioning Methods 0.000 title abstract description 3
- 238000000034 method Methods 0.000 claims abstract description 58
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 claims abstract description 53
- 230000008569 process Effects 0.000 claims abstract description 36
- ZOOODBUHSVUZEM-UHFFFAOYSA-N ethoxymethanedithioic acid Chemical compound CCOC(S)=S ZOOODBUHSVUZEM-UHFFFAOYSA-N 0.000 claims abstract description 27
- 239000012991 xanthate Substances 0.000 claims abstract description 27
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims abstract description 25
- 235000011941 Tilia x europaea Nutrition 0.000 claims abstract description 25
- 239000004571 lime Substances 0.000 claims abstract description 25
- 229910052951 chalcopyrite Inorganic materials 0.000 claims abstract description 22
- DVRDHUBQLOKMHZ-UHFFFAOYSA-N chalcopyrite Chemical compound [S-2].[S-2].[Fe+2].[Cu+2] DVRDHUBQLOKMHZ-UHFFFAOYSA-N 0.000 claims abstract description 22
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 claims abstract description 21
- 239000003153 chemical reaction reagent Substances 0.000 claims abstract description 9
- XFXPMWWXUTWYJX-UHFFFAOYSA-N Cyanide Chemical compound N#[C-] XFXPMWWXUTWYJX-UHFFFAOYSA-N 0.000 claims abstract description 5
- 239000012141 concentrate Substances 0.000 claims description 30
- 239000002002 slurry Substances 0.000 claims description 30
- 230000003750 conditioning effect Effects 0.000 claims description 26
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 14
- 229910052760 oxygen Inorganic materials 0.000 claims description 14
- 239000001301 oxygen Substances 0.000 claims description 14
- 239000011435 rock Substances 0.000 claims description 10
- 238000007667 floating Methods 0.000 claims description 7
- 150000004763 sulfides Chemical class 0.000 claims description 7
- 239000002562 thickening agent Substances 0.000 claims description 6
- 239000007787 solid Substances 0.000 claims description 5
- 230000000881 depressing effect Effects 0.000 claims description 4
- 229910052500 inorganic mineral Inorganic materials 0.000 claims description 4
- 239000011707 mineral Substances 0.000 claims description 4
- HYHCSLBZRBJJCH-UHFFFAOYSA-M sodium hydrosulfide Chemical compound [Na+].[SH-] HYHCSLBZRBJJCH-UHFFFAOYSA-M 0.000 claims description 3
- 229910052979 sodium sulfide Inorganic materials 0.000 claims description 3
- GRVFOGOEDUUMBP-UHFFFAOYSA-N sodium sulfide (anhydrous) Chemical compound [Na+].[Na+].[S-2] GRVFOGOEDUUMBP-UHFFFAOYSA-N 0.000 claims description 3
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical class S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 claims description 2
- 229910052783 alkali metal Inorganic materials 0.000 claims description 2
- 150000001340 alkali metals Chemical class 0.000 claims description 2
- 229910052784 alkaline earth metal Inorganic materials 0.000 claims description 2
- 150000001342 alkaline earth metals Chemical class 0.000 claims description 2
- HIVLDXAAFGCOFU-UHFFFAOYSA-N ammonium hydrosulfide Chemical compound [NH4+].[SH-] HIVLDXAAFGCOFU-UHFFFAOYSA-N 0.000 claims description 2
- UYJXRRSPUVSSMN-UHFFFAOYSA-P ammonium sulfide Chemical compound [NH4+].[NH4+].[S-2] UYJXRRSPUVSSMN-UHFFFAOYSA-P 0.000 claims description 2
- 230000000994 depressogenic effect Effects 0.000 claims description 2
- 238000007865 diluting Methods 0.000 claims description 2
- 239000006260 foam Substances 0.000 claims description 2
- 239000007788 liquid Substances 0.000 claims description 2
- 230000015572 biosynthetic process Effects 0.000 claims 1
- 230000001143 conditioned effect Effects 0.000 abstract description 9
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 44
- 229910052759 nickel Inorganic materials 0.000 description 22
- 238000012360 testing method Methods 0.000 description 20
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 13
- 229910052802 copper Inorganic materials 0.000 description 13
- 239000010949 copper Substances 0.000 description 13
- 238000005273 aeration Methods 0.000 description 9
- 239000000463 material Substances 0.000 description 7
- 238000004140 cleaning Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 230000008859 change Effects 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 229920006395 saturated elastomer Polymers 0.000 description 3
- 230000008719 thickening Effects 0.000 description 3
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- 238000003556 assay Methods 0.000 description 2
- 238000011021 bench scale process Methods 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- YOCUPQPZWBBYIX-UHFFFAOYSA-N copper nickel Chemical compound [Ni].[Cu] YOCUPQPZWBBYIX-UHFFFAOYSA-N 0.000 description 2
- 230000002950 deficient Effects 0.000 description 2
- 238000010790 dilution Methods 0.000 description 2
- 239000012895 dilution Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 238000007670 refining Methods 0.000 description 2
- 241001140714 Citrus latifolia Species 0.000 description 1
- 241001644893 Entandrophragma utile Species 0.000 description 1
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 1
- 241000965606 Saccopharyngidae Species 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000013043 chemical agent Substances 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000007885 magnetic separation Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 150000002825 nitriles Chemical class 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000002516 radical scavenger Substances 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- WWNBZGLDODTKEM-UHFFFAOYSA-N sulfanylidenenickel Chemical compound [Ni]=S WWNBZGLDODTKEM-UHFFFAOYSA-N 0.000 description 1
- WJCNZQLZVWNLKY-UHFFFAOYSA-N thiabendazole Chemical compound S1C=NC(C=2NC3=CC=CC=C3N=2)=C1 WJCNZQLZVWNLKY-UHFFFAOYSA-N 0.000 description 1
- 125000000101 thioether group Chemical group 0.000 description 1
- 238000009827 uniform distribution Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
- B03D1/00—Flotation
- B03D1/02—Froth-flotation processes
- B03D1/06—Froth-flotation processes differential
Landscapes
- Manufacture And Refinement Of Metals (AREA)
Abstract
FLOTATION SEPARATION OF PENTLANDITE FROM
PYRRHOTITE USING SULFUR DIOXIDE-AIR CONDITIONING
ABSTRACT OF THE DISCLOSURE
A flotation process for the selective beneficiation of sulfide ore. In brief, the ore is slurried, conditioned with sulfide reagent, thickened and ground, conditioned with xanthate, floated and conditioned with lime, sulfur dioxide and air to depress pentlandite and promote chalcopyrite and pyrrhotite flotation. The chalcopyrite is promoted by use of cyanide and control of redox potential.
PYRRHOTITE USING SULFUR DIOXIDE-AIR CONDITIONING
ABSTRACT OF THE DISCLOSURE
A flotation process for the selective beneficiation of sulfide ore. In brief, the ore is slurried, conditioned with sulfide reagent, thickened and ground, conditioned with xanthate, floated and conditioned with lime, sulfur dioxide and air to depress pentlandite and promote chalcopyrite and pyrrhotite flotation. The chalcopyrite is promoted by use of cyanide and control of redox potential.
Description
`~3~3~3 FLOTATION SEPARATION OF PENTLANDITE FROM
PYRRHOTITE USING SULFUR DIOXIDE-AIR CONDITIONING
.
TECHNICAL FIFED
The instant invention relates to beneficiati.on of complex sulfide ores in general and, more particularly, to a process that preferentially renders pentlandite unfloatable while leaving chalcopyrite and pyrrhotite floatable for subsequent separation.
BACKGROUND ART
In the Sudbury district of Canada, as well as in other parts of the world, nickel is found in a complex, finely disseminated ore with other valuable metals including copper. The principal sulfide mlnerali~ation consists of pentlandite (No, Fox, chalcopyrite (Quaffs) and pyrrhotite (Fun US ) with the undesirable pyrrhotite (which itself contains only a minor portion of nickel in solid solution being present in amounts far greater than the pentlandite.
I
PYRRHOTITE USING SULFUR DIOXIDE-AIR CONDITIONING
.
TECHNICAL FIFED
The instant invention relates to beneficiati.on of complex sulfide ores in general and, more particularly, to a process that preferentially renders pentlandite unfloatable while leaving chalcopyrite and pyrrhotite floatable for subsequent separation.
BACKGROUND ART
In the Sudbury district of Canada, as well as in other parts of the world, nickel is found in a complex, finely disseminated ore with other valuable metals including copper. The principal sulfide mlnerali~ation consists of pentlandite (No, Fox, chalcopyrite (Quaffs) and pyrrhotite (Fun US ) with the undesirable pyrrhotite (which itself contains only a minor portion of nickel in solid solution being present in amounts far greater than the pentlandite.
I
2 PC-2174 For example, the ratio of pyrrhotite to pentlandlte may be approximately 5:1. The ores and the separation thereof have been under study for many years and much has been discovered as a result.
The processes which have been adopted for beneflciation of these complex ores involve the separation of the values into a nickel stream, a copper stream, a pyrrhotite stream and reject guying or rock stream, are essentially compromises in which overall recovery of desired metal values and degree of concentration are balanced. Thus, in flotation of the ores the practice of forming a bulk nickel-copper concentrate with rejection of pyrrhotite and guying followed by further flotation to provide separation of nickel and copper has been adopted. In effecting nickel-copper separation, chalcopyrite is floated preferentially to pentlandite. It is necessary to float a large proportion of pyrrhotite to recover slow floating fine pentlandite and middling particles. Thus, substantial quantities of pyrrhotite remain with the nickel concentrate with the result that the nickel concentrate analyzes approximately lo% of nickel. In contrast, the copper concentrate resulting will contain approximately 30% of copper. The nickel concentrate still contains copper and the copper concentrate still contains nickel, factors which co~pllcate further processing in eke smelter. The pyrrhotite concentrate rejected from the circuit should be as low as possible in nickel and copper.
The fact that, in the interest of maximizing nickel (or copper recovery, the nickel concentrate presently obtained it of relatively low grade, means that the total content of sulfur in the nickel concentrate fed to the smelter is higher than is wanted in terms of operating cost, nickel throughput, losses of nickel, losses of cobalt and emissions of sulfur dioxide. For example, raising concentrate grade from about 11% to about 17% nickel would cut sulfur dioxide emissions approximately 25%, a highly desirable result, and other economies can be achieved. While provision of means for treating nickel sulfide ore to provide a nickel concentrate of improved grade has long been recognized as an objective, no practical means for doing so without encountering severe economic handicaps ha heretofore been developed.
The processes which have been adopted for beneflciation of these complex ores involve the separation of the values into a nickel stream, a copper stream, a pyrrhotite stream and reject guying or rock stream, are essentially compromises in which overall recovery of desired metal values and degree of concentration are balanced. Thus, in flotation of the ores the practice of forming a bulk nickel-copper concentrate with rejection of pyrrhotite and guying followed by further flotation to provide separation of nickel and copper has been adopted. In effecting nickel-copper separation, chalcopyrite is floated preferentially to pentlandite. It is necessary to float a large proportion of pyrrhotite to recover slow floating fine pentlandite and middling particles. Thus, substantial quantities of pyrrhotite remain with the nickel concentrate with the result that the nickel concentrate analyzes approximately lo% of nickel. In contrast, the copper concentrate resulting will contain approximately 30% of copper. The nickel concentrate still contains copper and the copper concentrate still contains nickel, factors which co~pllcate further processing in eke smelter. The pyrrhotite concentrate rejected from the circuit should be as low as possible in nickel and copper.
The fact that, in the interest of maximizing nickel (or copper recovery, the nickel concentrate presently obtained it of relatively low grade, means that the total content of sulfur in the nickel concentrate fed to the smelter is higher than is wanted in terms of operating cost, nickel throughput, losses of nickel, losses of cobalt and emissions of sulfur dioxide. For example, raising concentrate grade from about 11% to about 17% nickel would cut sulfur dioxide emissions approximately 25%, a highly desirable result, and other economies can be achieved. While provision of means for treating nickel sulfide ore to provide a nickel concentrate of improved grade has long been recognized as an objective, no practical means for doing so without encountering severe economic handicaps ha heretofore been developed.
3 PC-2174 Coupled with the above, it has become increasingly important to reduce eke quantity of sulfur dioxide (S02) emissions. Sulfur dioxide it an undesirable byproduct of sulfide ore refining. Current gas treatment and sulfuric acid production are exceedingly expensive. Accordingly emphasis has been placed on removing as much pyrrhotite as possible before the treated ore is subjected to pyrometallurgical techniques.
Obviously, the more sulfur one can remove during the initial stages of ore processing, the less sulfur dioxide one will have to contend with during the final refining stages.
Flotation is one of the most useful mineral dressing techniques available to the engineer for concentrating valuable minerals contained in ores. Many specific flotation techniques have been developed for the treatment of specific ores and a wide selection of chemical agents has been employed to provide a variety of beneficial results in applying such techniques.
However, as far as can be determined, there is no commercial flotation process that separates pentlandite from pyrrhotite. The only other flotation process that succeeds in doing this is the subject of Canadian patent 1,156,380 but that process has not been commercialized.
This process uses sodium carbonate and cyanide jointly which leaves pentlandlte and chalcopyrite floatable while depressing pyrrhotite.
Unfortunately, this process consumes a great quantity of cyanide and leaves stable complex metal cyanides in the effluent. Other flotation methods currently in use are at best modestly effective. For instance in what is referred to by some as the pyrrhotite rejection circuit in Into Limlted's Copper Cliff mill (located in Sudbury, Ontario) recovers only 60% of the nickel as jell as 25% of the pyrrhotite.
SUMMARY OF TIE INVENTION
Accordingly, there is provided a flotation process for expeditiously rejecting pyrrhotite while recovering most of the pentlandite and chalcopyrlte from a mixture containing these sulfides and associated silicate rode minerals.
~V~3~
The process conditions the feed, removes rock, subjects the material to a sulfur dioxide/air stream, regulates the pi of the flow stream to first separate the pentlandite from the stream then floating the chalcopyrite, and leaving the pyrrhotite behind.
Thus, the invention provides a flotation process for selectively beneficiating sulfide ore, the ore including, amongst other things, pentlandite, chalcopyrite and pyrrhotite, the process comprising slurring the ore, introducing a reagent to the slurry to resorb xanthate present in the slurry, removing the lo xanthate and liquid, adding sufficient xanthate to the ore to allow -the sulfides to float to form a bulk sulfide concentrate while leaving the rock as a non-float stream, diluting the bulk sulfide concentrate to a second slurry, adjusting the pi level of the second slurry, adding sulfur dioxide and air, and floating the second slurry to recover chalcopyrite and pyrrhotite as a float product while depressing the pentlandite.
BRIEF DESCRIPTION OF THE DRAWING
Figure 1 is a generalized flow sheet of the invention.
Figure 2 is a modification of the invention.
Figure 3 is a graph depicting separation efficiency.
PREFERRED MODE FOR CARRYING OUT THE INVENTION
figure 1 represents the flowchart of the process.
The feed in the following discussion is low grade material obtained from Into Limited's Copper Cliff mill. The stream is generated after removing the readily floatable chalcopyrite and pentlandite and rejecting by magnetic separation most of the monoclinic pyrrhotite. It should be appreciated, however, that the disclosed process may be utilized with the ,, . ,~,...
Jo J - 4 -I
appropriate materials regardless of the source.
The feed in this instance analyzes about 3% chalcopyrite (Quaffs) 5% pentlanclite (Nix foe 2S8), 40% pyrrhotite (Phase), and 50% rock. The objective is to recover the chalcopyrite and pentlandite as separate concentrates while rejecting all of the pyrrhotite and rock.
Simply for ease of discussion, the ensuing treatment applies to a one kilogram sample of feed. Larger quantities are to be treated proportionally. In any event, the feed was slurries to two liters of pulp.
The process begins with an operation that has been dubbed a sulfide wash. The purpose of this step is to provide a means for removing excess xanthate that may accompany the feed material as a consequence of previous processing. Following addition of a sulfide bearing reagent (sodium sulfide, sodium hydrosulfide, ammonium sulfide, or ammonium hydrosulfide, for example) the pulp is conditioned for a few minutes and is then -thickened during which time the pulp is raked Jo - pa -~.3~3~
continuously. Indeed, the sulfide reagent may be selected from the sulfides or hydrosulfides of the alkali metals or alkaline earth metals.
It is also within the purview of this invention to utile a lime wash instead of the sulfide wash.
0.5 g/kg of sodium sulfide was added, after which the pulp was conditioned for five minutes. The purpose of the raking is to ensure that the pulp and liquor are mixed 80 that xanthate resorbed from the sulfides is distributed uniformly throughout the liquor. It is known that conditions necessary for xanthate resorption are a highly negative REDO potential and oxygen deficient conditions. Following thickening for an extended period (17 hours) the liquor is decanted and discarded in order to remove the resorbed xanthate.
The thickened solids are then ground at 50% solids by weight to produce a size distribution with 35~ retained on 37 em. Following grinding an addition of fresh xanthate is made (usually 0.07 go of feed) and the sulfides are floated away from the rock. The flotation time was sixteen minutes.
The bulk sulfide concentrate produced in the foregoing step will contain virtually all of the chalcopyrite, pentlandite and pyrrhotite that was in the feed. Typically about 40% ox the original weight reports to the rock tails which assay about 0.1~ Cut 0.25% No and contain approximately 4% each of the copper and eke nickel.
The bulk sulfide concentrate diluted to 1.7Q of slurry, it heated to 40C, the pi is downwardly adjusted to 8.1 if necessary, then sulfur 25 dioxide is added at a rate of 9 mQ/min for 50 minutes. The total S02 addition is therefore 450 my or 1.2 g. (1.2 grams/1.7 liter or 0.71 grams liter Air is added at a rate of 590 ml per minute simultaneously during the S02 sparring to insure that the dissolved oxygen level it maintained above about 5.4 ppm. During the addition of sulfur dioxide and air the pulp is stirred vigorously to generate a vortex which prevents foam from accumulating on the surface of the pulp. After 50 minutes of sulfur dioxide addition the gas flow is stopped and sufficient lime is added to the pulp while at 40C to produce a pit of 11.5. The pulp is conditioned for an additional 20 minutes with vigorous stirring so as to again generate a vortex. Air was added again to maintain the dissolved oxygen above about 5.4 ppm.
I
Following this S02/air/lime conditioning the bulk sulfide concentrate is subjected to flotation for about ten minutes.
Chalcopyrite and pyrrhotite are floated while pentlandite is depressed.
In a good test 95% of the chalcopgrlte and more than 90% of the pyrrhotite will be in the float product lath less than 25% of the pentlandite. The floated material is returned to the cell for a cleaning flotation stage Lime is again added to produce a pi of 11.5 then the pulp is subjected to flotation at ambient temperature The non-float portion from the first and second (cleaner) flotation stages which it identified as the pyrrhotite cleaner tails) is combined as the nickel concentrate. The material floated in the cleaner stage contains virtually all of the chalcopyrite and most of the pyrrhotite.
To effect a chalcopyrite/pgrrhotite separation the floated material is conditioned in a saturated lime solution (conditioned with 1.6 grams of lime), adding a small amount (0.1 gram) of cyanide then conditioning with aeration until the REDO potential (A versus saturated calmly) rises to a least -225 my then floating the chalcopyrite over a four minute period. The non-float portion is the final pyrrhotite 20 concentrate. Typically it analyzes about 90% pyrrhotite, 1.4% No (1~5%
Nope and contains approximately 75% of the pyrrhotite along with 10% of the pentlandite.
The copper concentrate produced from this single flotation stage analyzed about 16% copper and contained By% of the copper in the feed 25 It also analyzed 1.2% No, 31~ pyrrhotlte with 2.7% of the nickel and 4.4 of the pyrrhotite.
More particularly, the results are shown below:
I
TABLE I
PENTLANDITE/PYRRHOTITE SEPARATION RESULTS
ASSAY (%) DISTRIBUTION (%) Cut No S Pro Wit Cut No Pun Pro Product Cut Kink 1.230.331.0 5.980.3 2.7 2.4 4.4 Pro Kink 1.335.987.8 35.29.4 17.4 9.1 74.6 No Kink 12.022.227.3 16.516.S 75.4 84.8 10.9 Rig Tails 0.1 0.28 4.2 9.9 10 FEED 1.2 2.619.941.4 Ok = Rock Pro = Pyrrhotite Cone. = Concentrate Pun = Pentlandlte The following discussion relates to the particular parameters selected.
A. pi and Conditioning Time The effects of final pi and conditioning time during the addition of S2 and air is shown in Figure 3. In these tests the procedure used was that shown in Figure 2. This procedure differs from the previous on in several aspects some of which are dependent on the sample history. No sulfide Nash (eke thickening stage described in the previous procedure) was done on this sample because it did not have an excess of xanthate.
Figure 3 is relevant, however, to the previous procedure Figure 3 shows the pentlandite/pyrrhotlte separation efficiency (SUE.) as a function of the conditioning time and final phi In this series of tests the S02 was added in a 1.5 White mixture with air. The actual S02 addition rate was 20 mQ/min until the pi reached the desired value at which time the gas addition rate was reduced so that the pi was maintained constant until the total conditioning time had elapsed. The entire conditioning was conducted at room temperature ( 25C).
The separation efficiency is a figure of merit used to evaluate the effectiveness of a physical separation process. It is simply calculated by taking the difference in flotation of pentlandite and pyrrhotite. In this work the fraction floated is based on the bulk sulfide concentrate. The loss of pentlandite and pyrrhotite in the rock 3~3 8 PC-~174 tails is not considered. The separation efficiency measures the fraction of the feed that was perfectly separated.
Figure 3 was obtained by using a stipples multiple regression program to generate an equation relating the SE to the two independent variables. Contours of SE were then generated from the regression equations. The results indicate an optimum condition of about pi 6.0 with about 110 minutes conditioning time. The numbers outside the contours indicate the actual experimental results.
B. Lime Wash During an earlier trial it was learned that the feed many times contained more xanthate than the Syria procedure could cope with at room temperature in 60 minutes. Since the amount of xanthate associated with the scavenger feed was also variable a method was sought by which the excess xanthate could be resorbed and the feed to the separation process stabilized. The method adopted was a lime wash. The lime wash was done by adding about 5 g of lime to 1 kg of feed in a 2.27 liter container filled with water. The slurry was agitated gently for 30 minutes then the slurry was allowed to settle for 45 minutes at which time the liquor was decanted and discarded. The thickened slurry was then ground, if necessary, the pi was adjusted with sulfuric acid to 9.5, xanthate was added, then the Syria conditioning was done.
C. Temperature-Time A series of tests was done on a sample A with this procedure. The parameters varied were the temperature during Syria conditioning and the duration of the conditioning period.
The optimum region was seen to be at 40C with a conditioning time of at least 60 minutes. An average of four tests done at these conditions was an SE of 0.77. It was determined that the Syria conditioning causes a depression of pentlandlte flotation whereas there is little impact on pyrrhotite. The best nickel in pyrrhotite corresponds to the optimum region for the separation efficiency.
D. pi Adjustment with Acid In conjunction with these tests others were done in which the pi was adjusted to the desired value (typically a pal of 6.5) before S02 was added. All of these tests failed to produce a significant separation owe which established that the separation observed following Swallower treatment was not due simply to pi adjustment, Furthermore, it was found that using sulfur dioxide alone to reduce the pi following the lime wash to pi 6.5 resulted in depression of too much pyrrhotite. Needless to say the S02 addition was too large.
E. Oxygen Level During Syria Conditioning An attempt was made to replicate the foregoing procedure on sample A. The test results are shown in Table II along with the dissolved oxygen levels during Syria conditioning.
TABLE II
RESULTS OF REPLICATED TESTS SAMPLE A
TestO~(ppm) SUE.
1 6-6.5 0.78 2 4.9-6.3 0.27 3 5.1-6.1 0.67
Obviously, the more sulfur one can remove during the initial stages of ore processing, the less sulfur dioxide one will have to contend with during the final refining stages.
Flotation is one of the most useful mineral dressing techniques available to the engineer for concentrating valuable minerals contained in ores. Many specific flotation techniques have been developed for the treatment of specific ores and a wide selection of chemical agents has been employed to provide a variety of beneficial results in applying such techniques.
However, as far as can be determined, there is no commercial flotation process that separates pentlandite from pyrrhotite. The only other flotation process that succeeds in doing this is the subject of Canadian patent 1,156,380 but that process has not been commercialized.
This process uses sodium carbonate and cyanide jointly which leaves pentlandlte and chalcopyrite floatable while depressing pyrrhotite.
Unfortunately, this process consumes a great quantity of cyanide and leaves stable complex metal cyanides in the effluent. Other flotation methods currently in use are at best modestly effective. For instance in what is referred to by some as the pyrrhotite rejection circuit in Into Limlted's Copper Cliff mill (located in Sudbury, Ontario) recovers only 60% of the nickel as jell as 25% of the pyrrhotite.
SUMMARY OF TIE INVENTION
Accordingly, there is provided a flotation process for expeditiously rejecting pyrrhotite while recovering most of the pentlandite and chalcopyrlte from a mixture containing these sulfides and associated silicate rode minerals.
~V~3~
The process conditions the feed, removes rock, subjects the material to a sulfur dioxide/air stream, regulates the pi of the flow stream to first separate the pentlandite from the stream then floating the chalcopyrite, and leaving the pyrrhotite behind.
Thus, the invention provides a flotation process for selectively beneficiating sulfide ore, the ore including, amongst other things, pentlandite, chalcopyrite and pyrrhotite, the process comprising slurring the ore, introducing a reagent to the slurry to resorb xanthate present in the slurry, removing the lo xanthate and liquid, adding sufficient xanthate to the ore to allow -the sulfides to float to form a bulk sulfide concentrate while leaving the rock as a non-float stream, diluting the bulk sulfide concentrate to a second slurry, adjusting the pi level of the second slurry, adding sulfur dioxide and air, and floating the second slurry to recover chalcopyrite and pyrrhotite as a float product while depressing the pentlandite.
BRIEF DESCRIPTION OF THE DRAWING
Figure 1 is a generalized flow sheet of the invention.
Figure 2 is a modification of the invention.
Figure 3 is a graph depicting separation efficiency.
PREFERRED MODE FOR CARRYING OUT THE INVENTION
figure 1 represents the flowchart of the process.
The feed in the following discussion is low grade material obtained from Into Limited's Copper Cliff mill. The stream is generated after removing the readily floatable chalcopyrite and pentlandite and rejecting by magnetic separation most of the monoclinic pyrrhotite. It should be appreciated, however, that the disclosed process may be utilized with the ,, . ,~,...
Jo J - 4 -I
appropriate materials regardless of the source.
The feed in this instance analyzes about 3% chalcopyrite (Quaffs) 5% pentlanclite (Nix foe 2S8), 40% pyrrhotite (Phase), and 50% rock. The objective is to recover the chalcopyrite and pentlandite as separate concentrates while rejecting all of the pyrrhotite and rock.
Simply for ease of discussion, the ensuing treatment applies to a one kilogram sample of feed. Larger quantities are to be treated proportionally. In any event, the feed was slurries to two liters of pulp.
The process begins with an operation that has been dubbed a sulfide wash. The purpose of this step is to provide a means for removing excess xanthate that may accompany the feed material as a consequence of previous processing. Following addition of a sulfide bearing reagent (sodium sulfide, sodium hydrosulfide, ammonium sulfide, or ammonium hydrosulfide, for example) the pulp is conditioned for a few minutes and is then -thickened during which time the pulp is raked Jo - pa -~.3~3~
continuously. Indeed, the sulfide reagent may be selected from the sulfides or hydrosulfides of the alkali metals or alkaline earth metals.
It is also within the purview of this invention to utile a lime wash instead of the sulfide wash.
0.5 g/kg of sodium sulfide was added, after which the pulp was conditioned for five minutes. The purpose of the raking is to ensure that the pulp and liquor are mixed 80 that xanthate resorbed from the sulfides is distributed uniformly throughout the liquor. It is known that conditions necessary for xanthate resorption are a highly negative REDO potential and oxygen deficient conditions. Following thickening for an extended period (17 hours) the liquor is decanted and discarded in order to remove the resorbed xanthate.
The thickened solids are then ground at 50% solids by weight to produce a size distribution with 35~ retained on 37 em. Following grinding an addition of fresh xanthate is made (usually 0.07 go of feed) and the sulfides are floated away from the rock. The flotation time was sixteen minutes.
The bulk sulfide concentrate produced in the foregoing step will contain virtually all of the chalcopyrite, pentlandite and pyrrhotite that was in the feed. Typically about 40% ox the original weight reports to the rock tails which assay about 0.1~ Cut 0.25% No and contain approximately 4% each of the copper and eke nickel.
The bulk sulfide concentrate diluted to 1.7Q of slurry, it heated to 40C, the pi is downwardly adjusted to 8.1 if necessary, then sulfur 25 dioxide is added at a rate of 9 mQ/min for 50 minutes. The total S02 addition is therefore 450 my or 1.2 g. (1.2 grams/1.7 liter or 0.71 grams liter Air is added at a rate of 590 ml per minute simultaneously during the S02 sparring to insure that the dissolved oxygen level it maintained above about 5.4 ppm. During the addition of sulfur dioxide and air the pulp is stirred vigorously to generate a vortex which prevents foam from accumulating on the surface of the pulp. After 50 minutes of sulfur dioxide addition the gas flow is stopped and sufficient lime is added to the pulp while at 40C to produce a pit of 11.5. The pulp is conditioned for an additional 20 minutes with vigorous stirring so as to again generate a vortex. Air was added again to maintain the dissolved oxygen above about 5.4 ppm.
I
Following this S02/air/lime conditioning the bulk sulfide concentrate is subjected to flotation for about ten minutes.
Chalcopyrite and pyrrhotite are floated while pentlandite is depressed.
In a good test 95% of the chalcopgrlte and more than 90% of the pyrrhotite will be in the float product lath less than 25% of the pentlandite. The floated material is returned to the cell for a cleaning flotation stage Lime is again added to produce a pi of 11.5 then the pulp is subjected to flotation at ambient temperature The non-float portion from the first and second (cleaner) flotation stages which it identified as the pyrrhotite cleaner tails) is combined as the nickel concentrate. The material floated in the cleaner stage contains virtually all of the chalcopyrite and most of the pyrrhotite.
To effect a chalcopyrite/pgrrhotite separation the floated material is conditioned in a saturated lime solution (conditioned with 1.6 grams of lime), adding a small amount (0.1 gram) of cyanide then conditioning with aeration until the REDO potential (A versus saturated calmly) rises to a least -225 my then floating the chalcopyrite over a four minute period. The non-float portion is the final pyrrhotite 20 concentrate. Typically it analyzes about 90% pyrrhotite, 1.4% No (1~5%
Nope and contains approximately 75% of the pyrrhotite along with 10% of the pentlandite.
The copper concentrate produced from this single flotation stage analyzed about 16% copper and contained By% of the copper in the feed 25 It also analyzed 1.2% No, 31~ pyrrhotlte with 2.7% of the nickel and 4.4 of the pyrrhotite.
More particularly, the results are shown below:
I
TABLE I
PENTLANDITE/PYRRHOTITE SEPARATION RESULTS
ASSAY (%) DISTRIBUTION (%) Cut No S Pro Wit Cut No Pun Pro Product Cut Kink 1.230.331.0 5.980.3 2.7 2.4 4.4 Pro Kink 1.335.987.8 35.29.4 17.4 9.1 74.6 No Kink 12.022.227.3 16.516.S 75.4 84.8 10.9 Rig Tails 0.1 0.28 4.2 9.9 10 FEED 1.2 2.619.941.4 Ok = Rock Pro = Pyrrhotite Cone. = Concentrate Pun = Pentlandlte The following discussion relates to the particular parameters selected.
A. pi and Conditioning Time The effects of final pi and conditioning time during the addition of S2 and air is shown in Figure 3. In these tests the procedure used was that shown in Figure 2. This procedure differs from the previous on in several aspects some of which are dependent on the sample history. No sulfide Nash (eke thickening stage described in the previous procedure) was done on this sample because it did not have an excess of xanthate.
Figure 3 is relevant, however, to the previous procedure Figure 3 shows the pentlandite/pyrrhotlte separation efficiency (SUE.) as a function of the conditioning time and final phi In this series of tests the S02 was added in a 1.5 White mixture with air. The actual S02 addition rate was 20 mQ/min until the pi reached the desired value at which time the gas addition rate was reduced so that the pi was maintained constant until the total conditioning time had elapsed. The entire conditioning was conducted at room temperature ( 25C).
The separation efficiency is a figure of merit used to evaluate the effectiveness of a physical separation process. It is simply calculated by taking the difference in flotation of pentlandite and pyrrhotite. In this work the fraction floated is based on the bulk sulfide concentrate. The loss of pentlandite and pyrrhotite in the rock 3~3 8 PC-~174 tails is not considered. The separation efficiency measures the fraction of the feed that was perfectly separated.
Figure 3 was obtained by using a stipples multiple regression program to generate an equation relating the SE to the two independent variables. Contours of SE were then generated from the regression equations. The results indicate an optimum condition of about pi 6.0 with about 110 minutes conditioning time. The numbers outside the contours indicate the actual experimental results.
B. Lime Wash During an earlier trial it was learned that the feed many times contained more xanthate than the Syria procedure could cope with at room temperature in 60 minutes. Since the amount of xanthate associated with the scavenger feed was also variable a method was sought by which the excess xanthate could be resorbed and the feed to the separation process stabilized. The method adopted was a lime wash. The lime wash was done by adding about 5 g of lime to 1 kg of feed in a 2.27 liter container filled with water. The slurry was agitated gently for 30 minutes then the slurry was allowed to settle for 45 minutes at which time the liquor was decanted and discarded. The thickened slurry was then ground, if necessary, the pi was adjusted with sulfuric acid to 9.5, xanthate was added, then the Syria conditioning was done.
C. Temperature-Time A series of tests was done on a sample A with this procedure. The parameters varied were the temperature during Syria conditioning and the duration of the conditioning period.
The optimum region was seen to be at 40C with a conditioning time of at least 60 minutes. An average of four tests done at these conditions was an SE of 0.77. It was determined that the Syria conditioning causes a depression of pentlandlte flotation whereas there is little impact on pyrrhotite. The best nickel in pyrrhotite corresponds to the optimum region for the separation efficiency.
D. pi Adjustment with Acid In conjunction with these tests others were done in which the pi was adjusted to the desired value (typically a pal of 6.5) before S02 was added. All of these tests failed to produce a significant separation owe which established that the separation observed following Swallower treatment was not due simply to pi adjustment, Furthermore, it was found that using sulfur dioxide alone to reduce the pi following the lime wash to pi 6.5 resulted in depression of too much pyrrhotite. Needless to say the S02 addition was too large.
E. Oxygen Level During Syria Conditioning An attempt was made to replicate the foregoing procedure on sample A. The test results are shown in Table II along with the dissolved oxygen levels during Syria conditioning.
TABLE II
RESULTS OF REPLICATED TESTS SAMPLE A
TestO~(ppm) SUE.
1 6-6.5 0.78 2 4.9-6.3 0.27 3 5.1-6.1 0.67
4 6.1-6.4 0.81 6.1-6.4 0.80 These results were decidedly surprising initially. An excellent separation was generated in test 1 (SE 0.78) however, test 2 failed to reproduce that result. Similarly, test 3, while better than 2 was not of the high caliber of 1. An examination of the test revealed that the dissolved oxygen was low at the beginning of S02 addition in tests 2 and 3. A procedural change was made: the pulp was saturated with oxygen during the heating of the pulp in test 4 and 5 so that oxygen was present when S02 addition was started. Clearly there was only a modest change observed in the measured values of dissolved oxygen but the results of the separation were vastly improved. Subsequently, the procedure has specified oxygen saturation during heating and no less than 5.4 ppm oxygen during S02 addition.
PC-~17 F. So Addition Rate Experiments were done on sample B with three different flow rates of sulfur dioxide. The total addition time was fixed at 60 minutes so the total volume of SO added was alpha changed when the flow rate was changed. The results indicate that for this procedure with this sample the optimum xanthate addition was 0.05 gig Furthermore it appears that within the range tested (480 my - 600 my per 60 minutes) the results were not affected much by the S02 addition rate. Since it is much easier to maintain a high level of dissolved oxygen with low addition rates of S02, a change was made in the procedure from 20 mQ/min to 9 mQ/min. Subsequently, a stipulation was added that the final pi could not be allowed to fall below 6. Thus, the total S02 addition time was reduced to 50 minutes.
G. Lime Aeration Prior to Pyrrhotite Cleaning The usual procedure included a cleaning flotation stage on the pyrrhotite rougher concentrate. Initially the pyrrhotite rougher concentrate was conditioned with Syria for lo minutes prior to cleaner flotation but this was relaxed to dilution wick water previously acidified to pi 6 with S02.
Because the lime aeration procedure for Queen separation is so effective in depressing pentlandite while floating both chalcopyrite and pyrrhotlte, this technique was evaluated. After 60 minutes of lime aeration the cleaning of the pyrrhotite concentrate was greatly improved as is shown by the results in Table III.
TABLE III
IMPACT OF LIME/AERAl`ION OF PYRRHOTITE ROUGHER CONCENTRATE
Sample Best S E Best nope SO~/airLime fir S02/airLime/air B 0.73 0.76 1.69 1.71 C 0.61 0.70 1.99 1.36 D 0.46 0.58 3.20 2.24 E 0.43 0.71 2.20 1.31 F 0.55 0.69 1.89 1.52 G 0.68 0.70 2.09 1.80 H 0.53 0.59 1.98 1.39 In every case the pentlandite/pyrrhotite separation efficiency was better with the lime aeration procedure than with standard of cleaning in pi 6 water.
An early pilot plant trial included an addition of sodium hydrosulfide then thickening to remove the resorbed xanthate. It was discovered very early in the program that very little xanthate was belong decanted but there was a high xanthate concentration in the liquor associated with the thickener under flow. It was known for a long time that a reducing or oxygen deficient environment was required for xanthate resorption but obviously this information was not fully utilized. To effect xanthate removal, the thickener underlie was pumped back to the thickener feed in a closed pipe. A bleed stream was taken from this recycle loop for feed to the process. This solved the problem. As a consequence of thus observation the laboratory procedure was reexamined.
It was found that in the static thickener there was a heterogeneous distribution of xanthate with the highest concentration associated with then thickened solids. To overcome this the solids were raked with a slow moving rake (8 rph). Samples taken at several levels in the thickener following 17 hours of raking showed a uniform distribution of xanthate.
The earlier circuit included Syria conditioning of the heated bulk sulfide concentrate, followed by a jingle stage of flotation. Prior to the pilot plant campaign, bench scale tests had included a pyrrhotite cleaning stage in which the dilution water had been acidified with S02 eon a pi of 6. The run did provide a ready source of pyrrhotite rougher concentrate. Advantage was taken of this availability to do a series of batch bench scale cleaner flotation tests after conditioning with lime and aerating. Pyrrhotlte flotation improved modestly with increased aeration in lime but pentlandite flotation decreased substantially as the aeration time was extended; as a consequence, the cleaner separation efficiency (SUE.) increased from about 0.25 with no aeration to lust about 0.7 after 60 minutes aeration.
H. Hot Lime Conditioning A series of tests was undertaken to examine the effect of elevated temperature on the lime conditioning stage. This led to the addition of lime to the pulp at the end of the Syria conditioning which is done at 40C. The effect of conditioning time following lime addition is shown in Table IV.
TABLE IV
RESULTS OF TESTS WITH HOT LIME CONDITIONING
PROWAR TO PYRRHOTITE ROUGHER FLOTATION
(SAMPLE It Lime Condition Maximum SUE.
Time (mix) Observed Test 2 0.62 25 5 0.68 2 0.60 3 ~.74 4 0.70 S
I 0.69 6 3020 0.68 7 0.75 8 0.75 9 0.73 10 I
Twenty minutes conditioning lime following time addition to pi 11.5 at 40C is considered quite satisfactory.
While in accordance with provisions of the statute, there it illustrated and described herein specific embodiments of eke invention, those skilled in eke art will understand that changes may be made in the form of the invention covered by the claims and the certain features of the invention ma sometimes be used to advantage without a corresponding use of the other features.
PC-~17 F. So Addition Rate Experiments were done on sample B with three different flow rates of sulfur dioxide. The total addition time was fixed at 60 minutes so the total volume of SO added was alpha changed when the flow rate was changed. The results indicate that for this procedure with this sample the optimum xanthate addition was 0.05 gig Furthermore it appears that within the range tested (480 my - 600 my per 60 minutes) the results were not affected much by the S02 addition rate. Since it is much easier to maintain a high level of dissolved oxygen with low addition rates of S02, a change was made in the procedure from 20 mQ/min to 9 mQ/min. Subsequently, a stipulation was added that the final pi could not be allowed to fall below 6. Thus, the total S02 addition time was reduced to 50 minutes.
G. Lime Aeration Prior to Pyrrhotite Cleaning The usual procedure included a cleaning flotation stage on the pyrrhotite rougher concentrate. Initially the pyrrhotite rougher concentrate was conditioned with Syria for lo minutes prior to cleaner flotation but this was relaxed to dilution wick water previously acidified to pi 6 with S02.
Because the lime aeration procedure for Queen separation is so effective in depressing pentlandite while floating both chalcopyrite and pyrrhotlte, this technique was evaluated. After 60 minutes of lime aeration the cleaning of the pyrrhotite concentrate was greatly improved as is shown by the results in Table III.
TABLE III
IMPACT OF LIME/AERAl`ION OF PYRRHOTITE ROUGHER CONCENTRATE
Sample Best S E Best nope SO~/airLime fir S02/airLime/air B 0.73 0.76 1.69 1.71 C 0.61 0.70 1.99 1.36 D 0.46 0.58 3.20 2.24 E 0.43 0.71 2.20 1.31 F 0.55 0.69 1.89 1.52 G 0.68 0.70 2.09 1.80 H 0.53 0.59 1.98 1.39 In every case the pentlandite/pyrrhotite separation efficiency was better with the lime aeration procedure than with standard of cleaning in pi 6 water.
An early pilot plant trial included an addition of sodium hydrosulfide then thickening to remove the resorbed xanthate. It was discovered very early in the program that very little xanthate was belong decanted but there was a high xanthate concentration in the liquor associated with the thickener under flow. It was known for a long time that a reducing or oxygen deficient environment was required for xanthate resorption but obviously this information was not fully utilized. To effect xanthate removal, the thickener underlie was pumped back to the thickener feed in a closed pipe. A bleed stream was taken from this recycle loop for feed to the process. This solved the problem. As a consequence of thus observation the laboratory procedure was reexamined.
It was found that in the static thickener there was a heterogeneous distribution of xanthate with the highest concentration associated with then thickened solids. To overcome this the solids were raked with a slow moving rake (8 rph). Samples taken at several levels in the thickener following 17 hours of raking showed a uniform distribution of xanthate.
The earlier circuit included Syria conditioning of the heated bulk sulfide concentrate, followed by a jingle stage of flotation. Prior to the pilot plant campaign, bench scale tests had included a pyrrhotite cleaning stage in which the dilution water had been acidified with S02 eon a pi of 6. The run did provide a ready source of pyrrhotite rougher concentrate. Advantage was taken of this availability to do a series of batch bench scale cleaner flotation tests after conditioning with lime and aerating. Pyrrhotlte flotation improved modestly with increased aeration in lime but pentlandite flotation decreased substantially as the aeration time was extended; as a consequence, the cleaner separation efficiency (SUE.) increased from about 0.25 with no aeration to lust about 0.7 after 60 minutes aeration.
H. Hot Lime Conditioning A series of tests was undertaken to examine the effect of elevated temperature on the lime conditioning stage. This led to the addition of lime to the pulp at the end of the Syria conditioning which is done at 40C. The effect of conditioning time following lime addition is shown in Table IV.
TABLE IV
RESULTS OF TESTS WITH HOT LIME CONDITIONING
PROWAR TO PYRRHOTITE ROUGHER FLOTATION
(SAMPLE It Lime Condition Maximum SUE.
Time (mix) Observed Test 2 0.62 25 5 0.68 2 0.60 3 ~.74 4 0.70 S
I 0.69 6 3020 0.68 7 0.75 8 0.75 9 0.73 10 I
Twenty minutes conditioning lime following time addition to pi 11.5 at 40C is considered quite satisfactory.
While in accordance with provisions of the statute, there it illustrated and described herein specific embodiments of eke invention, those skilled in eke art will understand that changes may be made in the form of the invention covered by the claims and the certain features of the invention ma sometimes be used to advantage without a corresponding use of the other features.
Claims (19)
1. A flotation process for selectively beneficiating sulfide ore, the ore including, amongst other things, pentlandite, chalcopyrite and pyrrhotite, the process comprising slurrying the ore, introducing a reagent to the slurry to desorb xanthate present in the slurry, removing the xanthate and liquid, adding sufficient xanthate to the ore to allow the sulfides to float to form a bulk sulfide concentrate while leaving the rock as a non-float stream, diluting the bulk sulfide concentrate to a second slurry, adjusting the pH level of the second slurry, adding sulfur dioxide and air, and floating the second slurry to recover chalcopyrite and pyrrhotite as a float product while depressing the pentlandite.
2. The process according to claim 1 wherein the temperature of the second slurry is maintained between about 35 and about 50°C.
3. The process according to claim 1 further comprising raising the pH of the second slurry, after the addition of sulfur dioxide and air, to a pH value of about 11.5 while at about 40°C, then conditioning for a further period of time.
4. The process according to claim 1 further comprising raising the pH of the floated product from the second slurry, adding cyanide to the floated product from the second slurry, causing the REDOX potential of the slurry to rise to at least -225 mV, and floating the chalcopyrite.
5. The process according to claim 1 wherein the reagent is selected from the group consisting of sodium sulfide, sodium hydrosulfide, ammonium sulfide and ammonium hydrosulfide.
6. The process according to claim 1 wherein the reagent is selected from the group consisting of the sulfides and hydrosulfides of the alkali metals and alkaline earth metals.
7. The process according to claim 1 wherein the pH of the second slurry is adjusted to about 8 prior to the introduction of sulfur dioxide.
8. The process according to claim 1 wherein sulfur dioxide is added to the slurry at a rate of about 0.7 grams per liter of slurry while simultaneously maintaining the oxygen level above about 5 ppm.
9. The process according to claim 1 wherein the pH of the second slurry is adjusted to a value between about 6 and about 6.5 by the addition of sulfur dioxide and air.
10. The process according to claim 1 wherein the second slurry is stirred to form a vortex to reduce foam formation.
11. The process according to claim 1 wherein the reagent is added to the first slurry at a rate of about 0.5 grams per kilogram of solids in the slurry.
12. The process according to claim 1 further comprising raising the pH of the second slurry, after the addition of sulfur dioxide and air, to a pH value of about 11.5 using lime while at about 40°C, then conditioning for a further period of time.
13. The process according to claim 1 further comprising raising the pH, using lime, of the pyrrhotite float product obtained from the second slurry to about 11.5 prior to conditioning for a period of about 20 minutes then doing a second or cleaner flotation in which the chalcopyrite and pyrrhotite are floated while pentlandite is depressed.
14. The process according to claim 1 wherein xanthate is added to the ore at a rate of about 0.07 gram per kilogram of ore.
15. The process according to claim 1 wherein the sulfide reagent containing slurry is raked in a thickener.
16. The process according to claim 1 wherein the thickened ore is ground to ensure liberation of the minerals.
17. The process according to claim 1 wherein the pH of the thickened ore is adjusted to about 9.5.
18. The process according to claim 1 wherein a lime wash is utilized to desorb the xanthate.
19. The process according to claim 13 wherein about 5 grams of lime are added to about 1 kilogram of ore.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000470472A CA1238430A (en) | 1984-12-19 | 1984-12-19 | Flotation separation of pentlandite from pyrrhotite using sulfur dioxide-air conditioning |
| AU50238/85A AU578327B2 (en) | 1984-12-19 | 1985-11-21 | Flotation separation of pentlandite from pyrrhotite using sulfur dioxide-air conditioning |
| FI854850A FI78403C (en) | 1984-12-19 | 1985-12-09 | AVSKILJNING AV PENTLANDIT GENOM FLOTATION AV PYRROTIT MEDELST ANVAENDNING AV SVAVELDIOXID-LUFTKONDITIONERING. |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000470472A CA1238430A (en) | 1984-12-19 | 1984-12-19 | Flotation separation of pentlandite from pyrrhotite using sulfur dioxide-air conditioning |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1238430A true CA1238430A (en) | 1988-06-21 |
Family
ID=4129403
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000470472A Expired CA1238430A (en) | 1984-12-19 | 1984-12-19 | Flotation separation of pentlandite from pyrrhotite using sulfur dioxide-air conditioning |
Country Status (3)
| Country | Link |
|---|---|
| AU (1) | AU578327B2 (en) |
| CA (1) | CA1238430A (en) |
| FI (1) | FI78403C (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5171428A (en) * | 1991-11-27 | 1992-12-15 | Beattie Morris J V | Flotation separation of arsenopyrite from pyrite |
| US5295585A (en) * | 1990-12-13 | 1994-03-22 | Cyprus Mineral Company | Method for achieving enhanced copper-containing mineral concentrate grade by oxidation and flotation |
| US5439115A (en) * | 1992-11-12 | 1995-08-08 | Metallgesellschaft Aktiengesellschaft | Process for selective flotation of copper-lead-zinc sulfide |
| US5992640A (en) * | 1994-11-16 | 1999-11-30 | Boc Gases Australia Limited | Precious metals recovery from ores |
| WO2009121147A1 (en) * | 2008-04-04 | 2009-10-08 | Bhp Billiton Ssm Development Pty Ltd | Odour control |
| US20110155651A1 (en) * | 2009-12-04 | 2011-06-30 | Barrick Gold Corporation | Separation of copper minerals from pyrite using air-metabisulfite treatment |
| CN113019684A (en) * | 2021-03-15 | 2021-06-25 | 中国恩菲工程技术有限公司 | Method for separating pyrite from pyrrhotite |
| CN113333170A (en) * | 2021-05-13 | 2021-09-03 | 西北矿冶研究院 | Method for improving main grade of zinc concentrate after copper-zinc separation |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6041941A (en) * | 1997-06-26 | 2000-03-28 | Boc Gases Australia Limited | Reagent consumption in mineral separation circuits |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA1062818A (en) * | 1976-01-30 | 1979-09-18 | Reichel A.G. Tenbergen | Flotation process |
| CA1104274A (en) * | 1978-12-04 | 1981-06-30 | Gordon E. Agar | Separation of sulfides by selective oxidation |
| ZA811606B (en) * | 1980-03-21 | 1982-03-31 | Inco Ltd | Selective flotation of nickel sulphide ore |
-
1984
- 1984-12-19 CA CA000470472A patent/CA1238430A/en not_active Expired
-
1985
- 1985-11-21 AU AU50238/85A patent/AU578327B2/en not_active Expired
- 1985-12-09 FI FI854850A patent/FI78403C/en not_active IP Right Cessation
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5295585A (en) * | 1990-12-13 | 1994-03-22 | Cyprus Mineral Company | Method for achieving enhanced copper-containing mineral concentrate grade by oxidation and flotation |
| US5171428A (en) * | 1991-11-27 | 1992-12-15 | Beattie Morris J V | Flotation separation of arsenopyrite from pyrite |
| WO1993010904A1 (en) * | 1991-11-27 | 1993-06-10 | Cheni Gold Mines Inc. | Flotation separation of arsenopyrite from pyrite |
| US5439115A (en) * | 1992-11-12 | 1995-08-08 | Metallgesellschaft Aktiengesellschaft | Process for selective flotation of copper-lead-zinc sulfide |
| US5992640A (en) * | 1994-11-16 | 1999-11-30 | Boc Gases Australia Limited | Precious metals recovery from ores |
| AU2009230891B2 (en) * | 2008-04-04 | 2014-08-07 | Bhp Billiton Ssm Development Pty Ltd | Odour control |
| WO2009121147A1 (en) * | 2008-04-04 | 2009-10-08 | Bhp Billiton Ssm Development Pty Ltd | Odour control |
| CN102056672A (en) * | 2008-04-04 | 2011-05-11 | Bhp比利通Ssm开发有限公司 | Odour control |
| US8734757B2 (en) | 2008-04-04 | 2014-05-27 | Bhp Billiton Ssm Development Pty Ltd. | Odor control |
| CN102056672B (en) * | 2008-04-04 | 2013-12-04 | Bhp比利通Ssm开发有限公司 | odor control |
| JP2013513025A (en) * | 2009-12-04 | 2013-04-18 | バリック・ゴールド・コーポレイション | Separation of copper minerals from pyrite using air-metabisulfite treatment |
| EP2506979A4 (en) * | 2009-12-04 | 2014-07-09 | Barrick Gold Corp | SEPARATION OF COPPER MINERALS FROM PYRITE BY AIR-METABISULPHITE TREATMENT |
| US20110155651A1 (en) * | 2009-12-04 | 2011-06-30 | Barrick Gold Corporation | Separation of copper minerals from pyrite using air-metabisulfite treatment |
| US9346062B2 (en) | 2009-12-04 | 2016-05-24 | Barrick Gold Corporation | Separation of copper minerals from pyrite using air-metabisulfite treatment |
| JP2016165728A (en) * | 2009-12-04 | 2016-09-15 | バリック・ゴールド・コーポレイションＢａｒｒｉｃｋ Ｇｏｌｄ Ｃｏｒｐｏｒａｔｉｏｎ | Separation of copper minerals from pyrite using air-metabisulfite treatment |
| US10258996B2 (en) | 2009-12-04 | 2019-04-16 | Barrick Gold Corporation | Separation of copper minerals from pyrite using air-metabisulfite treatment |
| CN113019684A (en) * | 2021-03-15 | 2021-06-25 | 中国恩菲工程技术有限公司 | Method for separating pyrite from pyrrhotite |
| CN113333170A (en) * | 2021-05-13 | 2021-09-03 | 西北矿冶研究院 | Method for improving main grade of zinc concentrate after copper-zinc separation |
| CN113333170B (en) * | 2021-05-13 | 2022-05-03 | 西北矿冶研究院 | Method for improving main grade of zinc concentrate after copper-zinc separation |
Also Published As
| Publication number | Publication date |
|---|---|
| AU5023885A (en) | 1986-06-26 |
| AU578327B2 (en) | 1988-10-20 |
| FI78403C (en) | 1989-08-10 |
| FI854850L (en) | 1986-06-20 |
| FI854850A0 (en) | 1985-12-09 |
| FI78403B (en) | 1989-04-28 |
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