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Патент USA US3098828

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July 23, 1963
'
A. c. DAMAN ETAL
3,093,818
CONCENTRATION APPARATUS AND METHOD
Filed April 5, 1961
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INVENTORS.
AFT/7UP C. Daman
Thomas S. Bailey, Jr’.
ATTORNEYS
July 23, 1963
3,098,818
A. c. DAMAN ETAL
CONCENTRATION APPARATUS AND METHOD
Filed April 5, 1961
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INVENTORS.
Arthur C. Damon
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Thomas S. Bailey, Jr
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July 23, 1963
3,098,818
A. c. DAMAN ETAL
CONCENTRATION APPARATUS AND METHOD
Filed April 5, 1961
4 Sheets-Sheet 3
INVENTORS
Arthur C. Daman
Thomas S. Bailey, Jr?
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July 23, 1963
- A. c. DAMAN ETAL
3,098,818
CONCENTRATION APPARATUS AND METHQD
Filed April 5, 1961
4 Sheets-Sheet 4
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INVENTORS.
Arfhur C. Daman
Thomas S. Bailey, Jr
BY
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ATTORNEYS
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United States Patent 0 ” 1C6
1
Patented July 23, 1963
2
terial will be reduced to extremely ?ne sizes; and best re
3,698,818
.
CONCENTRATION APPARATUS
NETHQD
Arthur C. Daman, Denver, Colo., and Thomas S. Bailey,
Jr., Johannesburg, Transvaal, Republic of South Africa,
assignors to Denver Equipment Company, Denver,
Colo., a corporation of Colorado
Filed Apr. 5, 1961, Ser. No. 100,879
9 Claims. ((11. 209-169)
covery is obtained where a minimum amount of the Icon
centrate material is in extremely coarse or extremely ?ne
sizes. As the grinding cost is a substantial part of the
entire milling expense, it is good economy, as well as
bene?cial to the recovery, to avoid excessive size reduc
tion in the grinding stage for the entire ore charge and
the present trend is toward coarser grinds. This practice
produces substantial amounts of coarse concentrate ma
Our invention relates to methods and apparatus for
concentrating the valuable constituents of a mixture of
solids in liquids, such as an ore pulp, and has particular
application but is not limited to improvements in froth
terial and coarse middlings, which collectively represent
only a small fraction of the ore, but are valuable enough
to warrant additional size reduction so as to obtain im
proved recovery.
The present invention involves a distinct departure
Flotation concentration is widely used in ore milling 15 from prior practices in having an adjunct concentration
?otation treatments.
and similar treatments requiring a metal or other valuable
constituent to be separated from other mineral or gangue
with which it is associated. Such a treatment requires
unit or stage which collects settled solids from an asso
to a ?otation size. ‘In the process a pulp is formed, the
liquid component of which acts as a carrier vehicle.
centrator operates continuously and discharges contin
uously in contradistinction to the intermittent batch type
discharge of the prior art.
ciated cell and subjects said solids to a sorting action for
separation of valuable constituents from gangue in a sim
separation of such constituents as by crushing and grind
ple, e?icient and economical manner. One of the inno
ing, in which action the separated particles are reduced 20 vations of the present invention is that the adjunct con
Prior to ?otation, the ore is conditioned by mixing with
one or more reagents as collectors and the conditioning
may include frothers and modi?ers as well.
Various supplemental concentrating procedures have
been proposed or used in the past as an adjunct to
Accordingly, it is an object of our invention to provide
25 a dual concentration in a single ?otation action which is
simple, ei?cient and economical and substantially reduces
tailings losses at the ?otation stage.
Another object of this invention is to provide a simple,
durable and efficient ?otation apparatus providing a dual
the ?otation concentration. Denny et a1. Patent No.
2,107,289 illustrates one arrangement of this type which
has provided an adjunct concentration applied to a unit 30 concentration in a single ?otation stage.
A further object of our invention is to provide series
cell ?otation machine. Daman Patent No. 2,122,028
illustrates another arrangement in which a jig is located
arrangement of secondary concentration apparatus which
underneath a unit cell machine as a mineral trap to col
provides a selective concentration of graded concentrates.
lect some of the heavier mineral concentrate which does
Yet another object of our invention is to provide a dual
not collect in the froth concentrate. According to the 35 concentration in which mineral concentrate and a mid
teachings of each of said patents, the under?ow material
dlings product are separately recovered and removed
passing into the adjunct concentrator is held therein and
from a ?otation treatment without increasing the power
only occasionally discharged from the trap. While the
input over that required for the primary concentration
of said treatment.
?otation cell operation is continuous, these machines pro
vide only intermittent discharge of the adjunct concen 40
A still further object of this invention is to provide a
trate, rather than a continuous discharge as performed by
combined classi?cation and ?otation concentration in
our process.
which the concentrate material reduced to a ?otation
In the usual ?otation operation, ground ore in a pulp
size is recovered as a froth concentrate while coarse sizes
of middlings and gangue are subjected to a separate con
is conditioned and then subjected to agitation and aer
ation in?uences in a series of cells in which the mineral 45 centration with oversize middlings and concentrate being
returned to the grinding stage for additional reduction
or other valuable constituent, responding to the in?uence
and further concentration.
of the collector reagent, is elevated in each cell by the
Further objects and advantages of our novel method
‘ buoyant effect of the air introduction and collects on the
and apparatus, including novel arrangements and com
surface in a froth, where it is removed by over?ow or the
bination of parts, according to the invention will be ap
action of mechanical Skimmers. While ?otation ma
parent to persons skilled in the art through study of the
chines and reagents have been improved to such an extent
following description. The practice of the invention will
that the ?otation separation per se produces a relatively
be readily understood by reference to the accompanying
high recovery, there is always a substantial tailings loss
in such separation, i.e., concentrate mineral passing from 55 drawings. In the drawings, in the several views of which
like parts bear similar reference numerals:
the treatment with the tailings, and a substantial recovery
‘FIG. 1 is a ?ow sheet representation of a typical circuit
improvement can be attained it the adjunct concentration
using one form of our multi-cell concentrating apparatus
can be performed ef?ciently at low cost.
7
adapted to perform the novel methods of our invention;
Many operations utilize a “hog-trough” ?otation ma
FIG. 2 is a second typical circuit having another form
chine in which the cell divisions of the unit permit a di
rect or substantially direct ?ow of pulp along the bottom 60 of multi-oell concentrating apparatus of our invention
used in performing the novel methods of our invention;
of the machine between its ‘feed inlet and tailings dis
FIG. 3 is still another typical circuit using our con
charge outlet. Solids settling on the bottom are swept
centrating apparatus in the practice of the novel meth
along by the action of the impellers and ?nally discharge
through the tailings outlet. As such solids accumulate, 65 ods of our invention, and utilizing a secondary concen
tration separate from the ?otation circuit;
concentrate material which otherwise might ?oat will be
FIG. 4 is a front elevation of a typical Denver Sub
entrained in the bed of solids and carried from the treat
A ?otation cell incorporating our novel concentrating
ment as tailings. Coarse middlings comprise a substan
means as an adjunct to the ?otation apparatus or cell
tial portion of the settled solids and likewise represent
a tailings loss.
and which is partially broken away to show arrange
70
ment of interior parts;
Operating experience has demonstrated that if the ore
is ground too ?ne, a large amount of the concentrate ma;
FIG. 4A is a top plan view of the concentrating ap
3,098,818
4
paratus of FIG. 4 shown as ‘detached from the cell of
FIG. 4 and drawn to an enlarged scale;
FIG. 5v is a fragmentary front elevation of another
type of ?otation cell, ‘broken away to show the arrange~
'rnent of interior parts and illustrating another form of
‘apparatus for cooperation with a ?otation cell for Oh
taining another concentrate from material not collecting
in the froth concentrate of such cell;
‘and are continuously removed through the outlet at the
bottom of the separator into a discharge line or con
duit 16.
The vortex action in separator 15a causes the lighter
fraction of the settled solids to be crowded upwardly into
the bottom portion of the cell in a displacement action
While the larger or heavier particles travel through the pulp
to the ‘bottom of the separator. So much of the elevated
material as returns to the ?otation machine without sus
FIG. 6 is a fragmentary front elevation of another ?ota
tion cell, partially broken away to show arrangements of 10 pending in the pulp therein ?ows toward the ?nal outlet 12
until it is drawn into and subjected to the action of sepa
interior parts with which the supplemental concentrator
rator 15b.
The treatment in separator 15b is essentially the same
as in separator 15a with more of the concentrate or mid
FIG. 7 is another fragmentary front elevation of still
another typical ?otation cell, partially broken away to 15 dlings material removed as an under?ow product. Each
of our invention has been incorporated in a different struc
tural form;
show the interior arrangement of parts and which utilizes
of the separators 15c, 15d, 15e progressively subjects the
a supplemental or adjunct concentrator according to our
entering matter to a separation according to size or spe
invention and a secondary treatment of said supplemental
ci?c gravity for discharge of the separated underflow
concentrate;
through a common discharge line or conduit 16.
but exemplary of novel apparatus arrangements which may
reground middlings material passing through the screen
The re
FIG. 8 is 1a flow sheet representation of another mul 20 sidual solids in the last cell, which are not removed by
separator 15e, are removed as waste through the tailings
tiple cell ?otation machine utilizing a different circuiting
outlet 12 of the machine. The combined separated heav
arrangement employing supplemental concentrating lap
ier or coarser fractions from the ?ve separators 15a
paratus according to our invention;
through 15c, are conducted by iine 16 to a classi?er 17
FIG. 9 is a vertical section of yet another type of com
mercial ?otation cell with which the concentrating appa 25 wherein a slimes fraction is removed through a waste
over?ow line 18 and a raked product is delivered into an
ratus of our invention is combined; and
other line l19 discharging into the feed inlet 20 of a ball
FIG. 10 is a fragmentary vertical section of still an
mill 21. Mill 21 may have other feed introduced through
other type of commercial ?otation cell with which the con
a supply line 20 if desired.
centrating apparatus according to our invention has been
30
A screening unit 22 is mounted at the discharge end of
combined.
mill 21 for removal of tramp oversize material which is
Before describing the arrangements shown in the draw
discharged from the treatment through line 23, while the
ings in detail, we wish it understood that said drawings are
22 is delivered by line 24- into a conditioner or surge tank
be used in the practice of our invention and are not in
tended as a limitation of the invention, the scope of which 35 25, where additional reagent may be supplied. Pump
is de?ned in the appended claims.
As it is quite common in ?otation circuiting to have a
substantial amount of coarser sizes in the feed to the
26 circulates the reground middlings product from tank
25 through a line 27 for return through the feed inlet 11
into the multi-stage ?otation apparatus 10. In some
multistage ?otation circuits there is not a su?icient time
?otation circuit, because the grinding circuit is regulated
to produce a minimum of ?nes and the larger sizes of the 40 interval for middlings and mineral constituents too large
to ?oat to settle on the bottom of the forward cells of
pulp often settle in substantial quantity on the bottom of
the operation. The circuit of FIG. 1 is particularly ef
the cell where they tend to spread beneath and around
fective under such conditions and provides an e?‘icient
the impeller, this results in a progressive buildup of settled
collection and separation of middlings for regn'nding and
solids on the bottom of the cell which contain a substantial
amount of concentrate. Concentrator apparatus accord
ing to our invention is usable with various mechanical
type ?otation cells, particularly “hog-trough” machines, to
return to ?otation. In such a treatment, the circulating
load is held to a minimum by elimination of slimes,
and the quantity of coarse concentrate and middlings sub
jected to additional grinding is only a fraction of the total
feed and as taiiings losses are substantially reduced by
described herein, provide cooperation between the blades 50 the regrinding, the additional recovery is obtained at
relatively low cost.
on the bottom of the impeller, and the upwardly opening,
Another circuiting arrangement has been illustrated in
conical separator beneath the impeller that establishes a
FIG. 2 which is particularly suited ‘for treatment of quick
continuous vortex in the separator which has characteristics
settling constituents of the pulp. The circuit of FIG. 2
of a centrifugal separator, with continuous segregation of
a ‘downwardly discharging, heavier or coarser fraction 55 includes a multicell ?otation apparatus 30 of the “hog
trough” type having a feed inlet 31, a tailings discharge
from said separator.
32, and a common froth concentrate over?ow launder
A typical multi-cell apparatus according to our inven
33 for the series of cells discharging through a nipple 34.
tion will be effective in a separation of a coarse from ?ne,
Four separator cones 35a, 35b, 35c and 35d are mounted
heavy from light, and in special sand removal operations.
beneath the impellers of the ?rst four cells; and a ?fth
One or a plurality of our separators are selectively spaced
separator 35e is mounted beneath a subsequent cell to
at intervals along the bottom of cells in a multi-cell ma
ward the tailings discharge end of the apparatus.
chine, such as the multi-stage ?otation machine 10 shown
These separators may have under?ow outlets of vary
in FIG. 1 having a feed inlet 11 at one end, a tailings dis
ing
size. In a preferred arrangement, cones 35a and 35b
charge 12 at its opposite end, and a froth over?ow launder
may have outlets on the order of 1%" or 1%" diameter
13 extending along a side of the series of cells and which
while 35c and 35d will have 1'' outlets. The greater dis
has a single outlet 14. Concentrators 15a, ‘15b, 15c, 15d
charge capacity of the ?rst two separators serves to re
and 15e are disposed beneath the impellers ‘of the last
move most of the settled mineral from ?otation, together
?ve stages or cells.
overcome the problems of concentrate loss through such
settling. In addition, the various arrangements shown and
with coarser middlings. The next two separators are of
In such an arrangement, the settled solids which are
70 lesser discharge capacity, as the major portion of the
not elevated or ?oated by the aeration or agitation are
solids entering such separators comprises tailings which
swept or drawn along the bottom beneath the impeller
are returned to the ?otation cells for ?nal removal with
until they are drawn into and reach the vortex in?uence
the tailings discharge through outlet 32. As shown in
of separator >15a, wherein the coarser or heavier settled
FIG. 2, the under-?ows of these separators are delivered
particles are separated in the centrifugal action therein 75 into a line 36. The cone 35c under?ow. while cont-aim
3,098,818
5
6
ing a substantial amount of tailings, is a product too
bottom of separator 78 for delivery of a tangential ?ow
valuable to waste which is primarily middlings and is
conducted through a line 38 to combine with the dis
charge of line ‘36 as feed to a pump 37.
of a lubricating ?uid, such as water, so as to main
tain a desired ?uidity to suit the sorting requirement of
the separation. The under?ow outlet .80, preferably hav
The combined discharge of the separators 35a, 35b,
35c, 35d and 35e is pumped through a tangential inlet
39 of a cycloneatype separator 40. A ?ner or lighter
ing an internal thread as shown, may be of any suitable
ball or rod mill ‘44. The remaining portion of this cir
cuit is substantially identical with that described in refer
ence to the circuit of FIG. 1. Tramp oversize is dis
separator 78 by the vortex in?uence and subjected to the
sorting action therein. As the separator 78 is subjected
to a considerable abrasive action in such sorting operation,
charged through a line 46 after rejection on a screen 45
we preferably provide a rubber liner 81 which extends
diameter to accommodate the discharge of said sep
arator.
fraction of the separation therein is removed as waste
Settled solids in cell 60 accumulate on the bottom and
through a conduit 41 and the thickened middlings under
entrain some solids which otherwise would ?oat or sus
?ow is conducted by a line 42 to the feed inlet 43 of a 10 pend in the pulp and said settled solids are drawn into
treating the discharge of the mill 44 and a reground 15 from the outlet nipple 80 to the top peripheral surface
middlings fraction is discharged into a conditioner or
adjacent the ?ange 82, so as to reduce wear and said liner
surge tank 4-8 through a line 47. A pump 49 recirculates
may be replaced when it deteriorates to preserve the sepa
the conditioned pulp through feed inlet 31 of ?otation
rator structure.
machine 30‘.
For some treatments, at high intensity vortex forma
FIG. 3 illustrates still another circuiting arrangement 20 tion may be required, and the arrangement shown in FIG.
providing additional treatment of the recirculated mid
5 is well suited for this purpose. As shown, the impeller
dlings and is similar to the circuit of FIG. 2, except that
has blades or vanes 84 on its undersurface positioned in
the discharges of the respective separators 35a through
close proximity to the top ‘of the separator and of such
3512 are treated for removal of constitutent solids before
size and disposed at an angle which will impart a high in
the remaining portion is subjected to regrinding. The 25 tensity centrifugal movement to the material in separator
combined discharge of cells 35a through 352, comprising
78‘. Again in this arrangement, an inlet 79' is included
middlings and coarser sizes of the valuable constituent
to provide ?uidity control and as the ?otation machine has
is subjected to further treatment. The treatment circuit
provision for adjusting the elevation \of the impeller and
as shown in FIG. 3 includes a concentrator, such as a
the elevation of blades 84 relative to the top of separator
concentrating table 51 or a mineral jig (not shown) to 30 78, the intensity of the vortex action may be closely con
which said combined discharge is fed by a line 52. The
trolled.
slimes and other tailings in ?ne sizes are discharged from
In FIG. 6 a slightly different type of separator cone 85
the table as waste and are removed by a line 53. The
is shown having a discharge nipple "86 at its bottom, an
concentrate of the ta-bling separation is removed through
upwardly opening conical portion 87, and an annular ex
a line 54 as a ?nal product, while the middlings are re 35 tension portion 88 above the conical portion 87. An in
moved at 55 and delivered as feed to a classifier 56.
let 91 in annular portion 88 supplies lubricating ?uid to
Any remaining slimes and other ?ne waste constituents
the top portion of the separation zone. A shaft 89 is se
are removed in the classifier over?ow 57, while the
classi?er raked product containing most of the collected
cured on and depends from the bottom of the impeller and
a bladed agitator 90 is mounted at the lower end of said
concentrate material is conducted through a line 58 40 shaft in approximately the‘ same elevation as the .inlet .91
and discharged as feed into the inlet 43 of ‘a ball mill
so as to supplement the action of the impeller in producing
44, for regrinding and further treatment in the same
an intense vortex effect. This arrangement is particularly
way as described with reference to the circuits of FIGS.
effective when substantial dilution is required in the sepa
1 and 2.
ration. The agitator mixes the liquid input .through'liquid
FIG. 4 represents a typical Denver Sub-A ?otation
inlet 91 with rthe pulp from the cell and provides thorough
cell to which a conical separator according to our inven
washing of the solids moving under the centrifugal in
tion has been connected. As illustrated, this cell is an
?uence in the separator. Such washing removes entrained
intermediate cell of a multicell machine and comprises a
slimes and ?nes from the coarser sizes and provides an
cell or tank 60 having a centrally disposed impeller 61
mounted on ‘a rotary shaft 62 driven by a sheave 63
of a power transmission system (not shown). The im
peller shaft 62 is disposed within a 'hollow column 64,
closed at its upper end by a bonnet 65, which has an air
inlet nipple 66.
Interconnected bearing assemblies 67
and 68 are supported on slotted adjustment plates 69
and 70 ‘for vertical adjustment of the entire assembly
supporting the impeller. A froth skimmer or rotary pad
essentially clean under?ow discharge.
FIG. 7 shows Ia different form of conical separator 78a
having its upper opening beneath the impeller '61 and this
separator has no water inlet for dilution of the pulp under
treatment. The under?ow discharge through the cone
outlet 80a passes through a conduit 8017. at a substantially
lower elevation to establish a hydraulic head directinga
tangential ?ow into another cyclone-type separator 95,
the rover?ow discharge of which passes through an outlet
dle 71, driven by a suitable transmission system 73 at
96 and its under?ow discharge passes through an outlet
a rate determined by a motor and speed reducer assembly
'72 ‘is provided vfor removal of froth from the surface of 60 97. The additional treatment of the under?ow discharge
from separator 78a in the hydro-cyclone 95 removes slimes
the liquid in the cell. Feed enters the cell through a
and finer particles through the upper outlet 96 while a
feed conduit 74 and is delivered onto the hooded im
cleaned
and graded concentrate is directed through the
pelle-r 61. The tailings discharge from the cell passes
bottom discharge outlet 97.
over a weir 75 positioned by a hand wheel 76 on a rod 77
Still another circuiting arrangement is shown in FIG. 8
and comprises the feed to the next cell in the series.
65
utilizing
a multi-cell ?otation machine 30, similar to the
A bottom opening in the cell is enclosed by a generally
apparatus arrangement of FIG. 3, including plural coni
conical separator 78 attached directly below and in
cal separators 35a through 35e. The circuit of FIG. 8
proximity to the impeller 61 which has its. bottom blades
differs from the FIG. 3 circuit in the distribution of the
in position to produce a vortex condition within the
separator. By having the bottom of the impeller in 70 under?ow products of the separators. When the ore un
der treatment has a substantial quantity of vfast settling
close proximity to the open top of the separator, we have
sands or other tailings constituents, some or all of the
found that substantially no power loss is encountered.
separators 35a through 35d may be used for tailings elimi
As some materials tend to pack too tightly in the cen
trifugal action of the vortex to the detriment of the
nation, and the under?ow of said separators may-be passed
sorting action, we provide an inlet nipple 7? adjacent the 75 directly to waste. Middlings are collected and'segregated
3,098,818
8
7
Comparative cell, no separator
Tailing: Total copper 0.93%
in separator 35a landrthe concentrate material is removed
as under?ow while sands separated therein are returned
to the machine 30 and are ?nally discharged at 12. The
middlings preferably are returned to a ball or rod mill in
the initial lore preparation stage of the plant circuit as sepa
Separator Screen Analysis
rator 35e does not produce enough under?ow material to
require a separate grinding mill installation.
,
Mesh Size of Screened
Fraction
Percent
FIGS. 9 and 10 are examples of other types of ?otation
cells which are adapted for modi?cation to utilize the novel
separator apparatus of our invention. In FIG. 9, the cell
100, has a centrally-disposed shaft 101 mounted for ro
tation and carrying an impeller 102 at its lower end, the
periphery of which comprises a series of downwardly ex
17.1
tending ?ngers in closely spaced arrangement. The im
peller 102 is mounted in close adjacency to and spaced 15
from the cell bottom and being of greater diameter than
the top of conical separator '7 8 encloses the opening to the
separator and the impeller ?ngers ‘assist the vortex forma
tion therein.
FIG. 10 illustrates another type of ?otation cell 104 hav 20
ing a rotary shaft 105 carrying a squirrel-cage rotor I106
disposed in a squirrel-cage enclosure 107. Pulp is drawn
into the enclosure through bottom openings in the im
peller 106 and is subjected to beating in?uence in its pas
sage between the bars or rods of the squirrel-cage of the
impeller and again in the passage through the rods or bars
Cumula- Assay, Distribu
tive,
Percent
tion,
percent Total Cu Percent
Total Cu
________ __
21. 2
19. 5
10. 2
7. 2
10.7
14. 1
38. 3
57.8
68.0
75. 2
85. 9
100. 0
100.0
100.0
2.14
30. 73
1. 47
1.03
0. 88
0.77
0.70
0. 65
26. 20
16. 90
7. 60
4. 60
6.30
7. 70
100.0
Comparative Cell Tailing for Same Period
_
Mesh Size of Screened
Fraction
Onmula-
Percent
2. 6
of the squirrel-cage enclosure. Mineral too coarse to ?oat
and oversize gangue settling in the cell pass into the sepa
tive,
percent
________ __
8. 2
12. 7
10.6
11. 4
20. 9
33.6
10.8
23. 5
34.1
45. 5
66. 4
100.0
100. 0
100.0
Assay,
Distribu
Percent
tion,
Total Cu Percent
Total Cu
l. 23
5. 4
1.02
0.77
0. 65
0.62
0.58
0.76
13. 3
13.9
10.9
11.2
13. 3
32.0
100.0
rator where the vortex action provides the sorting action
necessary to return gangue to the cell, While collected mid 30
dlings mineral is discharged through the under?ow out~
let 80.
In actual tests, ‘a separator according to our invention
During this period the ?ow was measured and also
speci?c gravity determined:
The average ?ow was 7.5 seconds per gallon of pulp
with an average pulp density of 1.45; assuming the speci?c
was ‘?tted to one cell of a multi-cell machine, in order to
gravity of solids at 2.9, this equals 30.8 dry tons of prod
35
determine whether a middling product could be produced
not per 24 hours.
containing a considerable proportion of the copper values
that did not =?oat readily in the cell. Preliminary tests
were run to determine the value of the product:
TEST 1
. In this test, a separator was mounted beneath the im
peller, water was introduced through the cone, and oper
ated continuously for several hours.
30.0 tons of dry solids per 24 hours discharged by a
separator and assaying 1.2% total copper equals 739.2
pounds per day of additional copper recovered from the
40 separator in this circuit.
From the above, it will be seen that our separator is
capable of recovering a substantial proportion of the cop
per normally discharging with the tailings otherwise rep
resenting a recovery loss.
The product discharge from the separator was assayed
In another plant test processing copper ore, an installed
and gave the following value:
45 bank of ?otation machines was modi?ed to include sepa
Total copper 3.21%
rators according to our invention, and the following tabu
TEST 2
lated results indicate the reduction in copper ore lost to
tailings when the separators were included:
In this test a 1" hose was ?tted to the cone and dis
Percent
50
charged continuously without addition of water.
First shift:
Copper
This was sampled continuously for 6 hours with the
Plant ‘tailing ___________________________ __ 0.93
following result:
Tailing from bank using separator _________ __ 0.62
Total copper 1.30%
Second shift:
During this period the tailing from the last cell was sam 55
Plant tailing ___________________________ .._
pled, giving the following result:
Total copper 0.63%
Comparative tests of a similar nature on similar units
0.80
Tailing from bank using separator _________ .._ 0.62
In all the arrangements of ?otation cell and conical sep
arator shown in the drawings, the top of the separator is
without separators, were conducted with the following 60 located beneath and in close adjacency to the impeller so
that the sweep of its rotation is utilized as the power
results:
Tailing for the day
source for the centrifugal movement of material within the
separator.. The centrifugal action therein causes heavier
Total copper 0.80%
or coarser solids to segregate and pass through the under
These results indicated that a considerable proportion 65 flow outlet in a substantially packed condition due to the
diminishing space of the separator as said constituents
of the content of the tailings copper was being recovered
with our separator and No. 3 test was then instituted, the
approach said outlet.
samples being screened and assayed.
In the same action, liquid and lighter or smaller sizes
are displaced by or are unable to penetrate the higher
TESTS
density under?ow material adjacent the outlet, and this
‘In this test, the separator product and tailing from the 70 sorting action is maintained throughout the period of con
last of a bank of cells were screened and assayed with the
following result:
Cone product: Total copper 1.20
Last cell tailing: Total copper 0.72
tinuous operation. If the solids in the cone tend to pack
so tightly that excessive wear on the cone surfaces results
or discharge is delayed, water or other lubricating ?uid
75 may be introduced through the inlet 79 or equivalent.
3,098,818
9
10
This lubricant introduction is effective in loosening and
elevating ?ner or lighter sizes which may have been en
trained in the material descending to the under?ow outlet
any other treatments where a middlings material tends
to settle in the cells and represents a tailings loss.
As the novel methods and practices of our invention
may be performed in a variety of apparatus as exempli
?ed in the drawings, it should be understood that the
so that the material passing through said outlet is essen
tially clean and in suitable condition for the subsequent
treatment, such as shown in FIGS. 11, 2 and 3.
In the various circuiting arrangements illustrated in
FIGS. 1, 2, 3 and 8, settled solids containing an appre
ciable quantity of mineral or the valuable constituent of
the treatment which otherwise would pass from the treat
ment and represent a metallurgical loss to the operation
is collected, segregated and separated as product with
resulting reduction in tailings losses. in addition, mid
speci?c structural forms shown in the drawings are merely
illustrative of the requirements of the invention and other
forms functioning in the same manner may be used.
Changes and modi?cations may be availed of within
10 the spirit and scope of the invention as set forth in the
hereunto appended claims.
We claim:
1. In a froth ?otation process in which one pulp con
dlings which otherwise would be lost or lessen the grade
stituent is ?oated and other pulp constituents settle and
of the concentrate product, if combined therewith, are 15 are removed ‘as tailings, the improvement which com
prises moving settled solids from the ?otation stage into
treated in closed circuit with a size reduction stage to re
turn to the ?otation stage in suitable size and condition
for ?nal recovery of substantially all the concentrate con
a vortex zone beneath and in direct communication with
said ?otation stage, continuously discharging a segre
tent of said middlings.
gated pulp fr-action ‘from the bottom of said vortex zone
By this arrangement, excessive grinding of the entire
in a volume less than its intake capacity so as to con?ne
ore charge is avoided and the quantity of material sub
a body of pulp in said zone, and subjecting .the solids so
jected to regrinding in the middlings treatment is only a
con?ned to .a vortex action in said vortex zone thereby
small fraction of the entire charge but contains enough
directing a continuous return ?ow of lighter or ?ner
concentrate material which is eventually removed as prod
solids into said ?otation stage and another continuous
uct to substantially improve recovery. The supplemental 25 ?ow of heavier or coarser solids from the vortex zone
separation of the conical separator provides additional
with the bottom discharge.
recovery of the collected concentrate material and segre
2. In a froth ?otation process in which one pulp con~
gates middlings material therewith which may be reground
stituent is ?oated and other pulp constituents settle and
and re?oated or otherwise treated to attain such improved
are removed as tailings, the improvement which corn
recovery, and said separator rejects waste material which 30 prises moving settled solids from the ?otation stage into
is returned into the ?otation machine where it ?nally dis
a vortex zone beneath and in direct communication with
charges as tailings.
said ?otation stage, continuously discharging a segre
With reference to the various structural modi?cations
gated pulp fraction from the bottom of said vortex zone
previously described, it should .be understood that the
in a volume less than its intake capacity so as to con?ne
shaping, size ‘and arrangement of the separators may be
a body of pulp in said zone, subjecting the solids so
varied according to the requirements of a :given treatment
con?ned to a vortex action in said vortex zone thereby
and the same is true of the arrangement of blades or
directing a continuous return ?ow of lighter or ?ner
suspended agitators on the underside of the impellers.
solids into said ?otation stage (and another continuous
Features described with reference to one drawing dis
?ow of heavier or coarser solids from the vortex zone
closure may be incorporated in any of the others and 40 with the bottom discharge, [and introducing ‘a stream of
similarly with respect to the circuiting following the
diluent ?uid into said vortex zone to maintain a free
segregation treatment, ‘any of the circuiting practices
?owing condition in the material being treated.
shown in relation to one term of separator may be ap~
3. The process of claim 2 in which the ?uid stream
is introduced in tangential ?ow adjacent the area of
continuous discharge from the vortex zone.
plied to all.
The various circuits illustrated disclose the collection
of settled solids, their treatment in a vortex zone to ob
tain a segregated coarser or heavier fraction, usually
middlings, which fraction is subjected to a size reduction
and the fraction after size reduction ‘is introduced as
feed to a ?otation stage. The drawings illustrate the re 50
turn of such fraction for introduction with the original
feed to the machine, but obviously such fraction may be
returned to any ?otation stage where it can be eifectively
handled.
4. A process for concentration of ores or the like in
a multi-stage treatment in which a ?otation pulp is in
troduced into a ?rst stage of such a treatment for pro
gressive ?ow through the succession of stages and one
pulp constituent is ?oated and other pulp constituents
settle and are removed as tailings, aerating the pulp in
each stage by rotating an impeller adjacent the bottom
of each stage with aerating gas delivered thereto for
surface removal of a froth concentrate, moving settled
Also in preferred practice, we provide a plurality or 55 solids in at least one ?otation stage into a vortex zone
succession of separators operating in conjunction with a
maintained beneath its impeller in direct communica
plurality of the ?otation cells. With certain pulps, only
tion with said one stage, continuously discharging a
a single stage may be required and it will be understood
segregated pulp ‘fraction :?rom the bottom of said vortex
that the use of a single stage separator is within the con
templation of our invention.
In treatments where a substantial amount of concen
zone in a volume less than its intake capacity so as to
60 con?ne a body of pulp in said zone, subjecting the solids
so con?ned to a vortex action in said vortex zone thereby
trate material other than middlings settles in the cells, it
will be advantageous to have a concentrating stage in
corporated in the recirculating treatment. We have shown
directing a continuous return ?ow of lighter or ?ner
solids into said at ‘least one ?otation stage and another
?ow of heavier or coarser solids into the bottom discharge,
the use of concentrating tables and cone separators and 65 continuously removing the heavier or coarser solids from
described the use of mineral jigs as an alternative con
said bottom discharge and subjecting the solids so removed
centrating apparatus. It is within the contemplation of
to size reduction, and introducing the reduced solids as
our invention that any suitable concentrating treatment
feed to a ?otation stage.
may be provided and the arrangement of equipment for
5. A process for concentration of ores or the like in
this purpose shown in the drawings is merely exemplary 70 a multi-stage treatment in which a ?otation pulp is intro
of the treatment to be performed.
duced into a ?rst stage of such a treatment for progressive
While the examples of the practice of our invention
?ow through the succession of stages and one pulp con
have involved a ?otation concentration of metallic ores,
stituent is ?oated and other pulp constituents settle and
the use of the invention may be applied to ?otation of
are removed as tailings, ‘aerating the pulp in each stage
non-metallics, such as potash ores, for example, or in 75 by rotating an impeller adjacent the bottom of each stage
3,098,818
11
12
With aerating gas delivered thereto for surface removal of
a froth concentrate, moving settled solids in a plurality
8. A process for reduction of the tailings loss of copper
content in concentration of copper bearing ores in hog
trough type ?otation apparatus, in which a ?otation pulp
of copper bearing ore is introduced into the feed end of the
of said stages into a vortex zo-ne beneath their respective
impellers maintained in direct communication with said
stages, continuously discharging a segregated pulp frac
tion from the bottom of the vortex zones in a volume
less than their respective intake capacities so as to con-_
?ne a body of pulp in each said zone, subjecting the solids
hog tnough apparatus and subjected to progressive ?ow
through a succession of agitation stages in said apparatus,
aerating the pulp in each stage by rotating an impeller
adjacent the bottom of each stage with aerating gas de
livered thereto for elevation and removal of a copper hear
so con?ned to a vortex action in said vortex zones thereby
directing a continuous return flow ‘of lighter or ?ner solids 10 ing froth concentrate, moving settled solids in a plurality
of said stages into a vortex zone beneath the respective
into the plurality of ?otation stages and another ?ow of
impellers maintained in direct communication with the
heavier or coarser solids into the respective bottom dis
charges thereof, continuously removing the heavier or
stages, continuously discharging a segregated pulp frac~
tion from the bottom of the vortex zones in a volume
coarser sol-ids from said bottom discharges, subjecting the
solids so removed to size reduction, and introducing the 15 less than their intake capacities so as to con?ne a body
of pulp in each said zone, subjecting the solids so con?ned
reduced solids after size [reduction as feed to a ?otation
stage.
6. A process for concentration of ores or the like in a
to a vortex action in said vortex zones thereby directing
a continuous return ?ow of lighter or ?ner solids into the
plurality of ?otation stages and another ?ow of heavier
multi-stage treatment inWhich a ?otation pulp is intro
or‘ coarser solids including concentrated copper content
duced into a ?rst stage of such a treatment for progressive
into the respective bottom discharges thereof, continuously
?ow through the succession of stages and one pulp con
removing the heavier or coarser solids and contained cop
stituent is ?oated and other pulp constituents settle and are
per from the bottom discharges, subjecting the solids so
removed as tailings, aerating the pulp in each stage by ro
removed to a classi?cation treatment in which the copper
tating an impeller adjacent the bottom of each stage with
aerating gas :delivered thereto for surface removal of a 25 content is separated from the gangue material, and recov
ering the separated copper values as product.
froth concentrate, moving settled solids in a succession of
9. A process for reduction of the tailings loss of cop
said stages into a vortex zone beneath their respective
per content in concentration of copper bearing ores in
impellers maintained in direct communication with said
hog-trough type ?otation apparatus, in which a a ?otation
stages, continuously discharging a segregated pulp frac
tion from the bottom of the vortex zones in a volume less 30 pulp of copper bearing ore is introduced into the feed end
than their respective intake capacities so as to con?ne a
of the hog trough apparatus and subjected to progressive
body of pulp in each said zone, subjecting the solids so
?ow through a succession of agitation stages in said ap
con?ned to a vortex action in said vortex zones thereby
directing a continuous return ?ow [of lighter or ?ner solids
paratus, aerating the pulp in each stage by rotating an
impeller adjacent the bottom of each stage with aerating
a froth concentrate, moving settled solids in at least one
?otation stage into a vortex zone maintained beneath its
impeller in direct communication with said one stage, con
contentis separated from the gangue material, subjecting
the separated copper content to size reduction, and in
into the succession of ?otation stages and another ?ow of 35 gas delivered thereto for elevation and removal of a cop
per bearing froth concentrate, moving settled solids in a
heavier or coarser solids into the respective bottom dis
plurality of said stages into a vortex zone beneath the re
charges thereof, continuously removing the heavier or
spective impellers maintained in direct communication
coarser solids from said bottom discharges, subjecting the
solids so removed to size reduction, and introducing the 40 with the stages, continuously discharging a segregated pulp
fraction from the bottom of the vortex zones in a volume
reduced solids after size reduction as feed to a ?otation
less than their intake capacities so as to con?ne a body of
stage.
pulp in each said zone, subjecting the solids so con?ned
7. A process for concentration of ores or the like in
to a vortex action in said vortex zones thereby directing
a multi-stage treatment in which a ?otation pulp is intro-4
duced into a ?rst stage of such a treatment for progressive 45 a continuous return ?ow of lighter ‘or ?ner solids into the
plurality of ?otation stages and another ?ow of heavier
?ow through the succession of stages and one pulp con
or coarser solids including concentrated copper content
stituent is ?oated and other pulp constituents settle and
into the respective bottom discharges thereof, continuously
are removed as tailings, aerating the pulp in each stage by
removing the heavier or coarser solids and contained cop
rotating an impeller adjacent the bottom of each stage
with aerating gas delivered thereto for surface removal of 50 per from the bottom discharges, subjecting the solids so
tinuously discharging a segregated pulp fraction from the
removed to a classi?cation treatment in which the copper
troducing the reduced copper content after size reduction
bottom of said vortex zone in a volume less than its in 55 as feed to a ?otation stage.
take capacity so as to con?ne a body of pulp in said zone,
subjecting the solids so con?ned to a vortex action in said
References Cited in the ?le of this patent
vortex zone thereby directing a continuous return ?ow of
lighter or ?ner solids into said at least one ?otation stage
UNITED STATES PATENTS
and another ?ow of heavier or coarser solids into the 60
851,600
Latimer ______________ __ Apr. 23, 1907
bottom discharge, introducing the heavier or coarser solids
2,107,289
Denny ________________ __ Feb. 8, 1938
removed from said bottom discharge into a concentration
stage for removal of a concentrate product, subjecting the
remainder of said fraction to size reduction, and intro
ducing said fraction after size reduction as feed to a ?o
tation stage.
'
2,122,028
2,928,543
2,964,179
Daman ______________ __ June 28, 1938
Logue _______________ .. Mar. 15, 1960
Loevenstein __________ __ Dec. 13, 1960
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