US3012670A

US3012670A - Flotation apparatus

Info

Publication number: US3012670A
Application number: US837174A
Authority: US
Inventors: Hans U Ziemer
Original assignee: International Minerals and Chemical Corp
Current assignee: International Minerals and Chemical Corp
Priority date: 1959-08-31
Filing date: 1959-08-31
Publication date: 1961-12-12
Anticipated expiration: 1978-12-12

Description

Dec. 12, 1961 2 Sheets-Sheet 1 Filed Aug. 51, 1959 His . Dec. 12, 1961 H. U. ZIEMER 3,012,670

FLOTATION APPARATUS Filed Aug. 31, 1959 2 Sheets-Sheet 2 4 HHH.. MII.

170775 U. Zzzlzef vbubbles throughout the cross-section of the cell. Ialso been diflicult to float mineral particles of relatively United States .Patent Ofllce [3,012,670 PatentedL Dec. 12, 1 961 3,012,670 FLOTATION APPARATUS Hans U. Ziemer, Lakeland, Fla., assigner to International Minerals & Chemical Corporation, a corporation of New York Filed Aug. 31, 1959, Ser. No. 837,174 2 Claims. (Cl. 209-168) The present invention generally relates to the art of benellciating materials by flotation techniques, and particularly to the control of flowing streams of liquids in flotation equipment, which streams have ore or other materials suspended or dispersed therein. Generally stated, a principal object of the invention is to provide improved ow control means for .flotation equipment.

The beneficiation of minerals by froth-dotation techniques is of great importance in the ore beneficiation art. The flotation process is widely used for treating lmetallic and non-metallic ores and, in addition, it is receiving an ever widening application in other. industries.

feed,"which is usually in the form of an aqueous pulp, is introduced horizontally into a flotation cell which is usually` constructed substantially in the form ofa cylinder or prism. The pulpis agitated and aerated in the flotation In many of the prior art flotation machines the mineral cell by a rapidly rotating irnpeller which rotates on a subvstantially vertical axis. The mineral-laden air bubbles separate' from the other material and pass upwardly to the pulp level of the flotation cell to form a froth. The 'froth is then floated oil of the top ofthe cell.

Since the pulp is introduced laterally into a flotation cell, in which the air bubbles are passing chiefly in upward direction, it has been difficult because of this difference in directions of flow to obtain a uniform distribution of air It has large mass in such a flotation cell.

A different type of flotationcell has recently been developed. This new ilotation cell is described indetail in copendingUnited States patent application No. 754,765,

filed August 13, 1958, now U.S. Patent No. 2,922,52l,

issued January 26, 1960. The apparatus described inthe copending'patent application includes an inlet conduitfor containing a flowing stream of fluid, and a laterally diverging conduit connected to the inflow conduit at the outflow end thereof for receiving the flowing stream of fluid l from the inflow conduit. The laterally diverging conduit comprises a part of the otation cell. Using this apparatus it has been possible, because of air and pump thrust upwardly into the diverging conduit, to effect. a

higher weight recovery of materials than can be obtained in more conventional flotation cells; for example, such 'cells as are used in Fagergren and Denver flotation macontrol means Within the diverging conduit system of a llo- The invention makes possible much more tation cell. positive and much more effective control of the ilow streams encountered in diverging conduit llotation cells than has heretofore been attained.

Further objects and advantages of the present invention companying drawings which illustrate several forms of lthe invention.

In the drawings, wherein are illustrated certain embodiments of the invention:

will be apparent from the following description and ac- FIGURE l is a sectional view of one form of notationY FIGURE 2 is a plan view illustrating another flotation l cell embodying certain features in accordance with the present invention;

FIGURE 3 is a sectional view, similar to FIGURE l, taken on the general line 3--3 of FIGURE 2;

FIGURE 4' is a sectionalview, similar to FIGURE l, illustrating stillother features of the invention;

FIGURE 5 is a partial lsectional view taken along line 5--5 of FIGURE 4. y v

FIGURE 6 is a plan view illustrating another flotation cell embodying still other features in accordance with the present invention; and V FIGURE 7 is a sectional view similar to FIGURE 4, taken on the general line 7-7 of FIGURE 6.

-The present invention provides an apparatus forvfroth ilotation beneiiciation of minerals in a manner that the tailing, or underflow from the flotation cell, contains less of the material which it is desired to float, than heretoforeobtainable.V The apparatus of the present invention is eminently useful in the beneficiation of potash ores such as sylvinite, langbeinite, mixed ores, etc., phosphate ores, and the like. The apparatus operates efficiently at large throughputs. The 'apparatus also makes possible the beneflciation of larger ore particles thanA are usually beneflciated in conventional flotation machines. .l f

In general, the flotation apparatus of the invention comprises an inflow conduit for containing a, flowing kstream of fluid, a laterally diverging conduit connected to the inflow conduit adjacent to the outllow end thereof for receiving the flowing stream of fluid from the inflowrconduit, and atleast one flow control member disposed within the diverging conduit to act upon the flowing stream to control the pressure and velocity relationships in the flowing stream. The flow control member preferably establishes a diverging flow pattern downstream of the outflow end of the inflow conduit. It will be understood that the particular structures illustrated inthe drawings are merely illustrative embodiments of thegeneral principles involved.

The apparatus provides a otation cell having a bottom inlet and an overflow adjacent to the upper end of the flotation cell. Between the inlet and overflow, the flotation cell is defined by essentially a rigid walled laterally diverging conduit section. The flotation cells, in accordtion cell as a jet. The pulp emergingfrom the inflow conduit flows as a more or less coherent or 4jet stream and,

when no flow control member is present in the cell, as it flows upwardly, the jet stream tends to spread out in the form of a mushroom vas the velocity decreases. The airladen mineral particles Vcontinue to rise to the froth level.

Since the jet stream carries the solid entrained particles mainly vertically upwardly, in the same direction that the air bubbles are rising, the adherence of the solid particles to the air bubbles is greatly facilitated vand at the same time a shaking or shearing of the solid particles 1from the bubbles is substantially reduced. For this reason the apparatus enables a reliable flotation of even unusually coarse particles with high efficiency.

It has, however, been observed that when using the apparatus without ilow control members for the beneficiation of material having particles larger than the size of the particles normally beneficiated in conventional flotation machines,-the`tailing or underflow from the flotation cell 3 is usually of poor quality; that is, the underflow contains mineral components which it is desired to tloat.

It has now been determined that when the dotation cell is provided with a flow control member in accordance with this invention, a substantial improvement in the operation of the otation cell is obtained.

A flotation cell employing various forms and arrangements of ow control means within the cell is illustrated in the drawings. The apparatus illustrated in the drawings includes an inow conduit 11 which is shown connected to the bottom of a rigid-walled, laterally diverging conduit or flotation cell 13. l

The tlotation cell 13 is illustrated as an inverted pyramid having a rectangular horizontal cross section; however, the diverging conduit may take on other forms such as an inverted cone. The inflow conduit 11 is also a discharge pipe of a centrifugal pump (not shown). The inflow conduit 11 extends upward and is provided with an extension 15 into the iiotation cell 13. In general, the length of the extension 15 into the otation cell depends upon the feed rate and the ratio of floated material to non-floated material. For example, when beneciating different materials, at substantially the same inflow conditions, if the ratio increased from 1:2 Ito 1:4, the extension 15 is preferably of relatively longer length in the latter operation.

The flotation cell 13 has connected adjacent its lowermost point a pipe 17 through which material may be withdrawn from the otation cell 13. The otation cell is provided at the top with

vertical walls

19, 21', 23 and 25 which together form a froth box. The upper edge of the wall 25 is somewhat lower than the upper edge of the other walls.

An overflow Weir 27 is suitably fixed in wall 25 and is positioned parallel to wall 25 and extends above the upper edge of this wall. The weir 27 is preferably adjustable in height by means not shown. A guide plate 29 is connected to the upper edge of wall 25, and this guide plate curves downwardly.

The apparatus described hereinabove in detail is also generally described in the hereinbefore referred to copending United States application No. 754,765. This co-pending application, however, describes an apparatus which does not include any ow control means between the diverging walls of the flotation cell. The present invention is particularly directed to the flow control means.

Referring now more particularly to FIGURE l of the drawings, there is illustrated a ow control means com prising a solid walled pyramid 31 positioned centrally with the flotation cell 13 on a grid 33. The grid 33 is fabricated of strip steel by overlaying a series of parallel strips with another series of parallel strips 37, with the lower strips 3S being generally perpendicular to the upper strips 37. The pyramid 31 is secured to the grid 33 by bolts 39. Instead of the illustrated pyramid 31, the flow control member may be embodied as a cone. The lower edges of the lower strips 35 of the grid 33 rest on the diverging walls of the otation cell 13. A grid is also positioned within the ilotation cell illustrated in FIGURES 2 and 3 and since the grid is substantially the same as the grid illustrated in FIGURE l, the same numerals, 33, 35, and 37, are used to designate corresponding parts of the grid. The tiow control means 41 illustrated in FIGURES 2 and 3 includes a solid walled upright pyramid 43 positioned centrally within the flotation cell 13 on the grid 33 and an inverted solid walled pyramid 45 attached to and depending from the grid. The vertical axis of the

pyramids

43 and 45 are substantially in alignment with each other and with the vertical axis of the flotation cell 13 and inlet conduit 11. The

pyramids

43 and 45 are secured to the grid 33 by bolts 47. The bases of the pyramids are of substantially the same size. Instead of the pyramids illustrated, one of the pyramids may be substituted for by a cone of substantially similar size and shape or both of the pyramids may be substituted for by cones of substantially similar size and shape.

The pyramids illustrated in FIGURES l, 2, and 3 constitute flow control elements which control and adjust the pressure and velocity relationships existing in the owing stream passing generally upwardly through the notation cell 13. In general, the flow control elements diverge the flowing stream more rapidly than the natural diverging which would occur in the absence of the ow control elements. In other words, the Flow control elements control and adjust the velocity of the owing stream so as to impart to the flowing stream a momentum or horizontal velocity component directed outwardly from the vertical axis of the otation cell, thereby diverting the stream from its normal path. The magnitude of the force delivered to the owing stream will,V of course, depend upon the angle of inclination of the surface of the pyramid to the normal direction of ow. The ow control element is preferably positioned relatively low in the cell, that is, in a lower portion of the cell, in order that the velocity of the owing stream may be altered as soon as possible, therefore permitting a large portion of the cell, downstream of the flow control element, to be utilized as a separating zone. The flow control member should, however, not be so low in the cell `that it adversely atects the solid particles in the owing stream themselves.

A otation apparatus embodying another flow control means in accordance with the general principles of the present invention is illustrated in FIGURES 4 and 5. This structure includes a plurality of guide vanes 49 symmetrically spaced and arranged across the lower section of the dotation cell 13. The guide vanes may be straight or may be curved (not illustrated). The leading edges of the vanes are rounded and the trailing end portions are tapered as indicated. The guide vanes are of a number and of a length suicient to diverge the flowing stream to the degree desired.

As illustrated in FIGURE 5, each of the guide vanes extend substantially from wall to wall of the tiotation cell.

Each of the guide vanes 49 is xedly mounted at a lower portion thereof on a spindle 51 .which extends through the walls of the flotation cell 13. Suitable packing seals 53 are provided around the spindles `in order to prevent Huid from leaking out of the otation cell.

The vanes 49 divide the stream of uid issuing out of the inow conduit 11 into a plurality of segments. Tne angle of inclination which the vanes 49 make with the normal direction of ow may be adjusted by rotating the spindles 51 until the desired predetermined angle is achieved and the vanes may then be fixed in this position. Any suitable means (not illustrated) may be used to adjust the angle and tix the vanes in position.

A flotation cell embodying another ow control means in accordance with the general principles of the present invention is illustrated in FIGURES 6 and 7. This structure includes four

guide vanes

55, 57, 59, and 61. The guide vanes 55 and 59 are tixedly mounted on

parallel spindles

63 and 65 respectively and the

guide vanes

57 and 61 are similarly tixedly mounted on

parallel spindles

67 and 69.

Spindles

63 and 65 are, however, substantially perpendicular to

spindles

67 and 69. The lower edges of the guide vanes terminate in substantially the same plane. In cross section, the vanes have leading edges which are rounded and the trailing end portions are tapered as indicated. The vanes have a narrow dimension (measured parallel to the respective spindle on which it is mounted) at the lower edges and widen toward the upper edges as indicated. The spindles extend through the walls of the otation cell and suitable packing seals 71 are provided around the spindles in order to prevent fluid from leaking out ot the otation cell. These spindles are adjustable to predetermined positions by means not illustrated, similar to spindles 51 so as to adjust the

vanes

55, 57, 59 and 61 to predetermined positions. In general, the vanes are adjusted so that the angles between each of the vanes and the Vertical axis or" the flotation cell are substantially equal.

Various flow control means in accordance with this invention have been illustrated and described with specific reference to certain construction details; however, it is to be understood that such details are illustrative only and not by way of limitation. Other modifications and equivalents will be apparent to those skilled in the art from the foregoing description.

A pilot plant size flotation cell was constructed in accordance with the embodiments described and illustrated in FIGURES 1, 2, and 3. This flotation cell was used in a series of tests. In all of the tests, the feed was an aqueous pulp of a fatty acid reagentized phosphate rock containing a major proportion of -14 +35 mesh size particles with the minor proportion predominantly -35 +150 mesh. As is known to those skilled in the art of beneficiating minerals by flotation, the -14 +35 material is usually considered too coarse for efllcient separation in conventional flotation equipment. All conditions were maintained substantially identical except as noted.

Test 1 The flotation cell was used without any flow control means within the cell. The results were as follows:

Product Wt., BPL, Recovery,

Percent Percent Percent Concentrate 51. 2 71. 67 8O Tailings 48. l 19. 20

Total 100. 0 46. 08 100. 0

Test 2 The flotation cell was provided with a grate (no pyramid) substantially like the grate illustrated in FIG- URE 1. The results were as follows:

Product Wt., BPL, Recovery,

Percent Percent Percent Test 3 The flotation cell was provided with an upright pyramid on the grate, substantially as illustrated in VFIGURE. 1. The results were as follows:

T est 5 The flotation cell was provided with two pyramids sub- 6 stantially as illustrated in FIGURES 2 and 3. The results were as follows:

The above tests illustrate the benefits obtainable when using flow control means in accordance with this invention.

Having now fully described and illustrated the invention, what is desired to be secured and claimed by Letters Patent is set forth in the appended claims.

l claim:

1. Flotation apparatus comprising in combination a substantially vertical inflow conduit for containing a flowing stream of a mineral feed in the form of an aqueous pulp, an upwardly extending laterally diverging conduit of rectangular horizontal cross section having a substantially vertical axis in substantial alignment with the vertical axis of said inflow conduit and having a bottom inlet connected t-o said inflow conduit adjacent the outflow end thereof, a froth box at the upper portion of said diverging conduit for receiving material from said diverging conduit, and an inverted solid walled pyramid disposed within said diverging conduit in a lower portion thereof and a s-olid walled upright pyramid disposed within said diverging conduit above said inverted pyramid and adjacent the lower end of said diverging conduit, said pyramids having substantially vertical axes in substantial alignment with the vertical axis of the inflow conduit, said pyramids acting upon the flowing stream to establish a diverging flow pattern within said diverging conduit downstream of the outflow end of the inflow conduit and control the pressure and velocity relationships in the flowing stream.

2. Flotation apparatus comprising in combination a substantially vertical inflow conduit for containing a flowing stream of a mineral feed in the form of an aqueous pulp, an upwardly extending laterally diverging conduit of rectangular horizontal cross section having a substantially vertical axis in substantial alignment with the vertical axis of said inflow conduit and having a bottom inlet connected to said inflow conduit adjacent the outflow end thereof, a froth box at the upper portion of said diverging conduit for receiving material from said diverging conduit, and an inverted solid walled pyramid having a substantially vertical axis in substantial alignment with the vertical axis of said inflow conduit disposed within said diverging conduit in a lower portion thereof to act upon the flowing stream to establish a diverging flow pattern within said diverging conduit downstream of the outflow end of the inflow conduit and control the pressure and velocity relationships in the flowing stream, a grid extending across the area of said diverging conduit with said inverted pyramid mounted thereon, and an upright pyramid supported on said grid above said inverted pyramid with the vertical axis of said pyramids in substantial alignment with the vertical axis of said inflow conduit.

References Cited in the file of this patent UNITED STATES PATENTS 2,142,207 Price Jan. 3, 1939 2,148,446 Drake Feb. 28, 1939 2,922,521 Schranz Jan. 26, 1960 FOREIGN PATENTS 593,185 Germany Sept. 20, 1931

Claims

1. FLOTATION APPARATUS COMPRISING IN COMBINATION A SUBSTANTIALLY VERTICAL INFLOW CONDUIT FOR CONTAINING A FLOWING STREAM OF A MINERAL FEED IN THE FORM OF AN AQUEOUS PULP, AN UPWARDLY EXTENDING LATERALLY DIVERGING CONDUIT OF RECTANGULAR HORIZONTAL CROSS SECTION HAVING A SUBSTANTIALLY VERTICAL AXIS IN SUBSTANTIAL ALIGNMENT WITH THE VERTICAL AXIS OF SAID INFLOW CONDUIT AND HAVING A BOTTOM INLET CONNECTED TO SAID INFLOW CONDUIT ADJACENT THE OUTFLOW END THEREOF, A FROTH BOX AT THE UPPER PORTION OF SAID DIVERGING CONDUIT FOR RECEIVING MATERIAL FROM SAID DIVERGING CONDUIT, AND AN INVERTED SOLID WALLED PYRAMID DISPOSED WITHIN SAID DIVERGING CONDUIT IN A LOWER PORTION THEREOF AND A SOLID WALLED UPRIGHT PYRAMID DISPOSED WITHIN SAID DIVERGING CONDUIT ABOVE SAID INVERTED AND ADJACENT THE LOWER END OF SAID DIVERGING CONDUIT, SAID PYRAMIDS HAVING SUBSTANTIALLY VERTICAL AXES IN SUBSTANTIAL ALIGNMENT WITH THE VERTICAL AXIS OF THE INFLOW CONDUIT, SAID PYRAMIDS ACTING UPON THE FLOWING STREAM TO ESTABLISH A DIVERGING FLOW PATTERN WITHIN SAID DIVERGING CONDUIT DOWNSTREAM OF THE OUTFLOW END OF THE INFLOW CONDUIT AND CONTROL THE PRESSURE AND VELOCITY RELATIONSHIPS IN THE FLOWING STREAM.