U.S. patent number 3,730,423 [Application Number 05/039,730] was granted by the patent office on 1973-05-01 for mineral dressing centrifuge.
Invention is credited to Gordon Raymond Coulson.
United States Patent |
3,730,423 |
Coulson |
May 1, 1973 |
MINERAL DRESSING CENTRIFUGE
Abstract
A method of mineral dressing and a mineral dressing centrifuge
especially suited to the separation and beneficiation of fine metal
values such as gold particles from suspensions of mixtures of said
metal values and a gangue in a liquid medium. A suspension of the
particulate mineral mixture in a suitable liquid medium is
introduced generally axially into a rotating centrifuge and
separated into its components by the settling rates of the
components in the liquid medium under the influence of centrifugal
forces. The components are separately discharged in liquid streams
issuing from a plurality of discharge outlets and are separately
collected. The centrifuge is of general frusto-conical
configuration having an axial feed inlet for introducing the
suspension into the larger end of the centrifuge and a plurality of
axially and circumferentially spaced discharge outlets.
Inventors: |
Coulson; Gordon Raymond
(Calgary, Alberta, CA) |
Family
ID: |
21907065 |
Appl.
No.: |
05/039,730 |
Filed: |
May 22, 1970 |
Current U.S.
Class: |
494/37; 494/74;
494/43 |
Current CPC
Class: |
B04B
11/06 (20130101); B04B 1/00 (20130101) |
Current International
Class: |
B04B
1/00 (20060101); B04B 11/00 (20060101); B04B
11/06 (20060101); B04b 001/00 () |
Field of
Search: |
;233/28,32,44,34,38,40,45,46,47R,19R,27,22 ;259/96 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
1,143,761 |
|
Feb 1963 |
|
DT |
|
241,180 |
|
Nov 1911 |
|
DD |
|
Primary Examiner: Krizmanich; George H.
Claims
I claim:
1. A method of mineral dressing which comprises introducing a
slurry of a particulate mineral mixture of metal values and a
gangue in suspension in a liquid medium, said metal values having a
greater specific gravity than the specific gravity of the gangue
minerals, generally axially into the large diameter end of a
centrifuge having a generally frusto-conical configuration with a
large diameter end and a small diameter end rotating about its axis
and having a plurality of circumferentially equispaced peripheral
liquid discharge outlets in a plurality of axially spaced planes
extending from said large diameter end to said small diameter end,
accelerating said mixture to substantially the centrifuge
rotational speed by impelling the slurry towards the centrifuge
periphery whereby said mixture is subject to centrifugal forces,
concurrently longitudinally moving the slurry through the
centrifuge from the large diameter end towards the small diameter
end, and separately discharging liquid streams containing said
particulate mineral mixture from said peripheral liquid discharge
outlets, whereby longitudinal travel of the slurry in the
centrifuge under centrifugal forces is effectual for component
separation of said particulate mineral mixture in accordance with
terminal velocities of the components of the particulate mineral
mixture.
2. A method as claimed in claim 1 in which the slurry is moved
longitudinally through the centrifuge by feeding the slurry to the
centrifuge at the large diameter end thereof under positive
pressure and discharging a substantial portion of the slurry liquid
from the centrifuge in proximity to or at the opposite end of the
centrifuge.
3. A method as claimed in claim 2 in which the slurry is
accelerated to substantially the centrifuge rotational speed by
substantially tangentially impelling said slurry towards the
centrifuge periphery at one end of the centrifuge and angularly
impelling the slurry during its travel through the centrifuge.
4. A method as claimed in claim 3, capturing solids settling in
proximity to nozzles in each axially spaced plane for discharge
from said nozzles, and separately collecting the discharge from
said nozzles.
5. A novel mineral dressing centrifuge which comprises a vessel
having a generally frusto-conical configuration with a large
diameter end and a small diameter end mounted for rotation about
its axis and having a plurality of circumferentially equispaced
liquid discharge outlets through its peripheral wall in a plurality
of axially separated planes extending from said large diameter end
to said small diameter end, means for introducing a slurry of a
particulate mineral mixture in a liquid generally axially into said
centrifuge vessel, an impeller mounted concentric with the
centrifuge at the large diameter end and adapted to rotate at the
centrifuge rotational speed, said impeller having an axial chamber
for receiving slurry from the feed pipe and having a plurality of
substantially tangential outlets in communication with said chamber
for equally distributing slurry towards the centrifuge periphery
while accelerating said slurry to substantially the centrifuge
rotational speed, means for maintaining the slurry at said
centrifugal rotational speed, and means for separately collecting
liquid streams discharging from each group of axially spaced apart
outlets.
6. A centrifuge as claimed in claim 5 in which said means for
introducing the slurry axially into the centrifuge comprises a feed
pipe disposed substantially concentric with the centrifuge and
terminating in proximity to or at one end of the centrifuge
interior.
7. A centrifuge as claimed in claim 5 in which said centrifuge has
a plurality of radial longitudinally disposed vanes for angularly
impelling the slurry to maintain the slurry of the centrifugal
speed.
8. A centrifuge as claimed in claim 7 in which means are provided
for effecting longitudinal travel of the slurry comprising liquid
discharge means at or in proximity to the small diameter end of the
centrifuge remote from the feed end adapted to discharge liquid at
a rate relative to the slurry feed rate sufficient to maintain a
positive longitudinal slurry flow within the centrifuge.
9. A centrifuge as claimed in claim 7 in which an annular baffle is
formed within the centrifuge between each adjacent set of axially
spaced nozzles.
Description
The present invention relates to mineral dressing centrifuges and
to a method of mineral dressing in which such a centrifuge is
utilized to beneficiate metal values in a particulate gangue. More
particularly, the invention relates to mineral dressing centrifuges
which, although useful in a wide range of mineral dressing
operations, have specific application in the separation of finely
divided gold particles from gold-bearing suspensions. This
invention is particularly applicable to the recovery of colloidal
and near-colloidal size gold particles from tailings from existing
gold separation treatments and from ores, the treatment of which
previously was considered not to be economically feasible.
Ores containing finely disseminated metal values often are
difficult to process due to slime production which results from
fine grinding of the ore necessary to liberate the said values
mechanically mixed with gangue minerals. Gold values, for example,
are formed in finely disseminated form mechanically mixed with
sulphides such as arsenopyrite and fine grinding of the ore results
in the liberation of colloidal and near-colloidal sized values
which are difficult to collect and separate from the fine gangue
minerals and which escape from the mill with the tailings. As a
result, mill tailings are known to contain considerable gold values
which to date have resisted attempts for commercial recovery of the
gold.
This invention is based on the finding that effective separation
and beneficiation of colloidal and near-colloidal size, e.g., from
less than about one to about 500 microns, gold particles from
particulate gangue materials may be effected by centrifuging a
slurry in the form of a suspension of such a particulate material
mixture in a liquid such as water.
The method of mineral dressing in accordance with the present
invention comprises introducing a slurry of a particulate mineral
mixture of metal values such as gold values and a gangue in
suspension in a liquid medium generally axially into a centrifuge
rotating about its axis, said centrifuge having a plurality of
circumferentially spaced apart peripheral liquid discharge outlets
in a plurality of axially spaced planes, accelerating said slurry
to substantially the centrifuge rotational speed whereby said
mixture is subjected to centrifugal forces in the centrifuge,
concurrently longitudinally moving the slurry through the
centrifuge i.e., parallel to the axis of the centrifuge, and
separately discharging liquid streams from said peripheral liquid
discharge outlets whereby longitudinal travel of the slurry in the
centrifuge is effectual for component separation of said mineral
mixture between said peripheral liquid discharge outlets.
The present invention also provides a novel mineral dressing
centrifuge which comprises a vessel mounted for rotation about its
axis and having a plurality of circumferentially spaced apart
liquid discharge outlets in a plurality of axially separated planes
through its peripheral wall, means for introducing a slurry of a
particulate mineral mixture in a liquid generally axially into said
centrifuge vessel, means for accelerating said slurry in the
centrifuge to substantially the centrifuge rotational sped, means
for effecting longitudinal travel of the slurry within the
centrifuge, and means for separately collecting liquid streams
discharging from each group of axially spaced apart outlets.
It is accordingly a principal object of the present invention to
provide a method of mineral dressing and mineral dressing
centrifuge by means of which mineral metal values may be
effectively beneficiated.
Another object of this invention is the provision of a method of
mineral dressing and a mineral dressing centrifuge by means of
which near-colloidal size gold particles can be effectively
recovered from particulate mineral mixtures containing same in an
economic and facile manner.
These and other objects of the invention and the manner in which
they can be attained will become apparent from the description of
the accompanying drawings, in which:
FIG. 1 is a vertical sectional view through a preferred embodiment
of a mineral dressing centrifuge in accordance with the
invention;
FIG. 2 is a horizontal plan view of the centrifuge of FIG. 1 partly
in section along the line 2--2 of FIG. 1.
FIG. 3 is an enlarged horizontal sectional view through the
centrifuge of FIG. 1 taken along the line 3--3 of that figure;
FIG. 4 is an enlarged and fragmentary vertical sectional view
through the peripheral wall of the centrifuge of FIG. 1 taken along
line 4--4 of FIG. 2 showing an outlet construction;
FIG. 5 is a schematic flow diagram illustrating the use in the
method of the invention of the centrifuge shown in FIGS. 1 to
4;
FIG. 6 is a schematic view of another embodiment of the centrifuge
in accordance with the invention;
FIG. 7 is a longitudinal section of a further embodiment of the
invention; and
FIG. 8 is a transverse section taken along line 8--8 of FIG. 7.
The mineral dressing centrifuge indicated generally at 10 in FIGS.
1-4 of the accompanying drawings comprises a frusto-conical vessel
12 having a peripheral conical wall 14 mounted on base 13 in
liquid-tight relation by O-ring 11, and a top member 15 formed
integral with wall 14. Nut 9 threaded onto conduit 39 locks top
member 15 and wall 14 to base 13. The vessel 12 is mounted for
rotation about its longitudinal axis A -- A by central securement
of base 13 to flange 17 of shaft 18 by connecting bolts 21
extending therethrough in a manner to be described. Shaft 18 is
journaled for rotation by extension downwardly through upper ball
bearing 19 and lower cone bearing 20 supported by housing 22 held
on machine frame comprising a top member 24 and upright members 25.
The structures of the bearing housing 22 and of the machine frame
will not be described herein in greater detail since they comprise
merely one technique for rotatably supporting the centrifuge and it
will readily be understood by those skilled in the art that
numerous types of bearing housings and support frames may be used
with the centrifuge of this invention.
Below the bearings 19 and 20, a pulley 28 is keyed to the shaft 18
as at 29 for receiving a driving belt, not shown, which is also
trained around a suitable source of motive power. An AC motor
operatively connected to a variable drive and a gear reducer has
been found to provide a suitable source of motive power with
satisfactory speed control.
From FIGS. 1 and 2, it will be seen that the peripheral wall 14 of
the centrifuge vessel 12 has sets of circumferentially spaced apart
liquid discharge nozzles 30 extending through wall openings 27 in a
plurality of axially spaced apart planes. In particular, it will be
seen from FIG. 1 that seven such axial sets of liquid discharge
outlets or nozzles 30 are provided through the periphal wall 14
while from FIG. 2 it will be noted that each such set comprises 12
liquid discharge nozzles 30 disposed at angular circumferential
separations of 30.degree.. For convenience, the seven axial sets of
nozzles are identified by the letters "B" through "H" in FIG.
1.
Referring to FIG. 4, it will be seen that each liquid discharge
nozzle 30 comprises a tubular portion 32 of reduced cross-section
which projects through and extends radially inwardly beyond the
inner surface 33 of the peripheral wall 14 and a tubular portion 34
of enlarged cross-section seated within the wall opening 27 such
that nozzle shoulder 31 abuts O-ring 35 against wall opening
shoulder 36. Nozzle 30 is secured in opening 27 by a lock screw 37
threaded in opening 27. Nozzle 30 and lock screw 37 have aligned
axial openings which together define a discharge opening 38. Each
discharge opening 38 is of sufficient diameter to ensure passage of
solids therethrough without bridging and without an excessive flow
of liquid. In the particular embodiment illustrated, the outer
surface 26 of the peripheral wall 14 of the centrifuge vesse 12 is
shown as having a stepped configuration, but this is not an
essential feature of this invention.
The centrifuge 10 also comprises an axially disposed feed conduit
39 which, as shown in FIG. 1, is secured to base 13 by bolts 21
passing through impeller plates 48,50 such that the impeller 49 is
disposed at the bottom of the centrifuge, i.e., the enlarged
portion of the centrifuge. Conduit 39 is friction-fitted through
boss 41 rigidly secured to the top member 15. It will be understood
that the feed conduit 39 is secured to the vessel 12 for
co-rotation therewith and, to permit control of the rate of
introduction of a slurry into the vessel 12, a non-rotatable
conduit portion 44 is freely and telescopically received in the
upper end of the conduit 39. O-ring 42 and packing 43 in internally
threaded collar 45 provide a water-tight seal between members 39
and 44.
In accordance with a particularly useful feature of this invention,
impeller 49 comprising spaced apart circular plates 48,50 is
secured to the feed conduit 39 concentric therewith at the open
lower end thereof for co-rotation for the purpose of imparting
radially outward motion to the particulate suspension introduced
into the vesse 12. In the particular embodiment illustrated, plate
50 is welded as at 51 about the lower end of the feed conduit
39.
With reference now to FIG. 3, impeller chamber 54 into which the
particulate suspension is discharged from the feed conduit 39 has a
plurality of substantially tangential outlets 55 defined between
plates 48,50 by wedges 53.
An annular baffle 58 is provided between adjacent sets "B" through
"H" of discharge nozzles 30. Referring in greater detail to FIG. 4,
it will be seen that the provision of such annular baffles 58
leads, on operation of the centrifuge 10, to the buildup of a bed
59 of particulate mineral material around each of the discharge
nozzles 30. This is particularly advantageous in reducing erosion
of the inner surface 33 of the peripheral wall 14 of the vessel
12.
Axially extending and radially disposed vanes 60, shown most
clearly in FIG. 2 and being provided between all adjacent sets of
nozzles, extend from abutment with the wall of conduit 39 to the
inner surface 33 of wall 14. Each of these radial vanes 60 is
retained in position by its engagement in radial slots 62 and 63
formed in the inner surfaces of the base 13 and the top member 15
respectively of the vessel 12. Each of baffles 58 is divided into
segments and anchored in slots formed radially in the sides of
vanes 60.
The mineral dressing centrifuge 10 also comprises a number of fixed
annular collectors or troughs 66B through 66H shown somewhat
schematically in FIG. 1. Each of these collectors is disposed so as
to receive a particulate material suspension stream from a
respective one of the sets "B" through "H" of the discharge nozzles
30. Four launder chutes 68 having a wedge-shaped configuration in
plan view are provided for draining the particulate material
suspension from each of the annular collectors 66 and these chutes
discharge at their lower ends into conduits 69 leading to settling
troughs 70B through 70H as shown somewhat schematically in FIG. 5
and which overflow into a drainline 71.
The method of the invention and the operation of the mineral
dressing centrifuge of FIGS. 1 to 4 will now be described in
greater detail with reference to FIG. 5 of the accompanying
drawings. From that figure, it will be seen that particulate
mineral mixture is fed through a feed line 74 to a grinder mill for
reduction therein of the particle size to a desired value to
liberate metal values from the gangue. From the mill 76, the
resulting ground mixture passes through line 78 to a slurry tank 80
in which it is thoroughly mixed with water fed through a water line
81 to form a slurry of a desired consistency. A perforated
deflector plate 82 is provided in this tank 80 to facilitate
mixing, and settling in this tank is prevented by a recycle pump 83
and associated lines 84 and 85.
From the slurry tank 80, the slurry passes through line 86 to a
screen classifier 87 for the separation of oversize material which
can, if desired, be recycled to the mill 76 through line 88. The
material passing through the screen classifier 87 then passes
through the feed line 90 to the fixed conduit 44 and into the feed
conduit 39 of the centrifuge 10. If desired, additional water may
be fed directly to the centrifuge through line 89.
The slurry can be fed to centrifuge 10 under pressure or by a
gravity flow utilizing conduit 44 to control the head. Centrifuge
10 can rotate at a speed of from about 200 to about 1,000
revolutions per minute (RPM) and the slurry feed pressure relative
to the liquid discharge through the nozzles must be adequate to
satisfy the discharges from nozzles H-C inclusive and to maintain a
liquid discharge from nozzles B. Nozzles B are of sufficient
capacity to permit variation of slurry flow.
Slurry discharged into the centrifuge is received in chamber 54 of
impeller 49 and impelled tangentially through impeller outlets 55
for acceleration to substantially the centrifuge rotational speed.
Vanes 60 then angularly impel the slurry to maintain the slurry
rotational speed. Liquid flow is induced upwardly, i.e.,
longitudinally, by the discharge of liquid from the upper nozzles,
i.e., nozzles B. The metal values such as, for example,
near-colloidal or colloidal gold, are believed separated from
particulate gangue by the method and apparatus of my invention, as
will be described in the following examples, due to the influence
of centrifugal forces on the solids whereby the coarser gold having
a greater specific gravity than the gangue settles first towards
nozzles H while the finer gold and gangue is retained in the liquid
and is carried upwardly away from nozzles H for discharge from the
remaining nozzles according to the solids' terminal settling
velocities in the liquid.
The following example is described with reference to a centrifuge
having an inside bowl diameter of 20 inches and a height of 83/4
inches with 3/32 inch nozzle openings in nozzle sets C - H
inclusive and 1/4 inch nozzle openings in nozzle set B.
EXAMPLE 1
A 10 per cent by weight solids in water slurry was fed to the
centrifuge at the rate of 25 GPM for a total of 50.65 pounds of ore
solids. The solids from tailings from a gold-arsenopyrite ore,
assayed 0.1093 troy ounces gold per ton. The centrifuge was
operated at a speed of 300 RPM. Table I illustrates the ratio of
gold to solids for each nozzle set and the centrifugal forces at
the centrifuge periphery.
TABLE I
Nozzle %Total %Total Ratio G's Gold Solids Gold:Solids H 32.0 25.15
1:1.28 23.0 G 15.4 14.00 1:1.10 20.4 F 5.3 4.85 1:1.10 17.9 E 5.4
6.00 1:0.9 15.3 D 2.9 2.80 1:1.04 12.8 C 0.8 0.90 1:0.89 10.2 B 0.7
0.80 1:0.88 6.6 Overflow 37.5 45.50 1:0.82 --
The concentrate from nozzles H was beneficiated 28 per cent and the
products from nozzles F and G were beneficiated 10 per cent.
EXAMPLE II
A 10 per cent by weight solids in water slurry was fed to the
centrifuge referred to above having 1/2 inch nozzles in set B. The
centrifuge was operated at 200 RPM at a flow rate of 50 GPM. The
solids in the slurry assayed 0.12 troy ounces gold per ton. The
products from the centrifuge are shown in Table II.
TABLE II
Nozzle %Total %Total Ratio Gold Solids Gold: Solids H (retained)
10.50 3.57 1:2.97 G (retained) 1.70 0.87 1:1.95 F-B (retained) 2.16
1.42 1:1.50 H 4.22 3.98 1:1.06 G 9.90 7.55 1:1.31 F-C 16.25 16.60
1:0.98 B 8.65 8.80 1:0.98 Overflow 46.70 57.20 1:0.81
The concentrate retained in the centrifuge at nozzle H was
beneficiated about 200 per cent. The concentrate retained in the
centrifuge at nozzle G was beneficiated about 95 per cent and at
nozzles F-B about 50 per cent.
EXAMPLE III
The liquid overflow from the system in Example II containing 0.09
troy ounces per ton gold was returned to the centrifuge under the
conditions of Example II except that the centrifuge speed was
increased to 300 RPM. The products from the centrifuge were as
follows in Table III.
TABLE III
Nozzle %Total %Total Ratio Gold Solids Gold:Solids H (retained)
15.08 11.60 1:1.30 G (retained) 5.78 4.45 1:1.30 F-B (retained)
6.85 6.85 1:1.00 H-B 27.18 27.46 1:0.99 Overflow 34.20 38.00
L:0.90
insufficient solids were present in the centrifuge to indicate
beneficiation in the nozzle discharge. However, the centrifuge
residues in proximity to nozzles H and G indicated a 30 per cent
beneficiation. No beneficiation was evident in the residues at
nozzles F-B.
The foregoing Examples indicate beneficiation of the mineral
mixture in the products to nozzles H and G, either in the residue
or in the nozzle discharge.
Although the description of the Examples has proceeded with
reference to a frusto-conical centrifuge having a feed impeller at
the base, i.e., wide end, and the truncated portion in an upwards
position, it will be understood that the centrifuge of this
configuration can be disposed on its side or inverted with the wide
end upwards. Also, the feed impeller can be centrally located at
the bowl end remote from the wide end. Centrifugal force created by
rotation of the centrifuge substantially overcomes the effects of
gravity and centrifuge disposition is therefore not critical. The
location of the feed impeller at the bowl narrow end remote from
the wide end can provide the advantages of increasing centrifugal
forces with reduced longitudinal slurry flow velocities as the wide
end of the bowl is reached such that the colloidal and
near-colloidal solids remaining in the slurry obtain optimum
effects from centrifugal forces with maximum retention time.
FIG. 6 illustrates such an embodiment of my invention in which the
frusto-conical bowl 140 is disposed with the wide end upwards. The
bowl includes a base plate 141 and a cover plate 143 and is
journaled for rotation in bearings 142, 144 and rotated by shelf
146 in a manner described with reference to my embodiment described
in FIGS. 1-4. Impeller 148 receives a slurry from feed conduit 150
and impels the slurry tangentially outwardly towards the periphery
of the centrifuge. Nozzles 152, which are disposed
circumferentially equispaced about the periphery of the bowl, are
arranged in a plurality of axially spaced apart planes and each
axial set of nozzles S, T, X, Y is separated from the adjacent set
by a baffle 154. Baffle 156 functions as an overflow ring or weir
and, in conjunction with the liquid discharge from nozzles 152,
rate of rotation of the centrifuge and rate of slurry feed,
controls the depth of liquid in the centrifuge bowl. The surface of
the liquid is designated by numeral 158. Longitudinal vanes 160
angularly impel the liquid at substantially the centrifuge
rotational speed.
The operation of this embodiment of my invention is substantially
the same as that of the previous embodiment described. Discharge
from nozzles 152 is collected in annular collectors 162S, 162T,
162X and 162Y, for discharge through lines 163S, 163T, 163X and
163Y respectively, the discharge from over-flow baffle 156 being
discharged from the centrifuge via openings 164 formed
circumferentially equispaced about the centrifuge periphery and
received in annular collector 166 leading to discharge lines
167.
It will also be understood that the centrifuge configuration is not
limited to a frusto-conical shape and can be cylindrical, as shown
generally in FIGS. 7 and 8. Cylindrical shell 100 is mounted for
rotation at one end 102 by a bearing 104 carrying feed pipe 106
flanged centrally onto end wall plate 108 and at the opposite end
110 by bearing 112 carrying outlet extension 124 flanged onto end
wall plate 126. The centrifuge can be rotated by a driving belt,
not shown, interconnecting pulley 114 with a source of motive
power, also not shown.
An impeller 116 is secured to wall 108 for rotation therewith. In
the embodiment shown, a plurality of circumferentially spaced apart
peripheral discharge outlet nozzles 118 are arranged in a plurality
of axially spaced planes P, Q and R i.e., eight nozzles in each of
three sets. Radial vanes 120 are disposed between each pair of
adjacent circumferentially spaced nozzles 118 and annular baffles
122 between each adjacent set P, Q and Q,R, as illustrated.
Annular collectors 128, each with an internal radial wall 129 which
defines an annular trough 130, are formed about each set P,Q and R
of nozzles 118 to receive and remove effluent from the nozzles 118
and to pass said material to discharge lines 132.
In operation the centrifuge is rotated at for example 200-1,000 RPM
or more. Slurry of the type hereinbefore described is introduced to
the centrifuge by feed pipe 106 and tangential impeller 116. The
slurry is rapidly accelerated to the centrifuge rotational speed
and, in flowing longitudinally through the centrifuge for discharge
via overflow ring 124 and via nozzles 118 to be received by
collectors 128, is acted upon by the centrifugal forces created.
Coarse gold values with high terminal velocities travel to nozzle
set P, together with coarse gangue, for a preliminary separation.
Finer gold and gangue travel to nozzle sets Q and R and water
containing some colloidal material flows over ring 124. The
longitudinal flow speed of the slurry can be controlled by the
volume of slurry fed to the centrifuge and by the discharge from
the nozzles, the latter being affected by nozzle diameters and G's
of centrifugal force. The paths taken through the centrifuge will
vary as to the characteristics of each ore, i.e., size and specific
gravity of particulate solids, and centrifuge speed, slurry solids
composition, slurry volume, nozzle size, overflow ring size, and
depth of annular baffles 122, which can be regulated by the artisan
to select a suitable combination of parameters.
Although three axially spaced sets P,Q and R of eight
circumferentially spaced nozzles 118 have been shown in FIGS. 7 and
8, and other combinations of, for example, five sets of 12 nozzles
each, can be used as is necessary for flow throughput, maximum
particle size and nature and degree of separation and beneficiation
desired.
* * * * *