US2496025A - Ore concentrator - Google Patents

Description

Filed March 12, 1949 1 W k W J. $TEPHAN ORE CONCENTRATOR mama 2 Sheets-Sheet l JOSEPH STEPHA/V INVENTOR.

Jan, M, wm J. @TEIPHAN ORE CONCENTRATOR 2 Sheets-Sheet 2 Filed March 12, 1M9

E m bm Q Wm KN 1 D 5 p mm 3 {M Patented Janl3l, 1950 OFFICE ORE CONCENTRATOR Joseph Stephan, Phoenix, Aria, assignor to The Stephan Corp'.,' a corporation Application March 12, 1949,;Serial No. 81,078

8 Claims. (01. 209-441 The invention relates to a machine for concentrating milled ores and classified placer, and for selectively grading the concentrates into any desired specific gravity range. The machine operates partially on the well known gravity stratification and water-washing principles embodied in many concentrating tables known in the past. However, my machine differs from those of the prior art primarily in achieving a continuous, rapid and positive ejection of concentrate of any desired specific gravity range from ores varying widely in complexity, mineral content and specific gravity range.

Briefly, the machine consists of an elongated rectangular table with transverse, diagonal, re-

ceding grooves over its entire concentration surface, adjustably but rigidly mounted on a bed to which is imparted a rapid longitudinal and vertical shaking motion. The longitudinal shaking motion is parallel to the direction of flow of pulp and tailings, and transverse to the concentrate flow, and to the grooves.

To my knowledge, no prior art machine satisfactorily achieves this overall aim, or the more specific objects of the invention which follow.

achieve a machine of greater capacity per square foot of table area than is possible with machines heretofore known. I achieve a higher capacity principally by providing extremely rapid vibration and a novel table contour which makes .pos-

sible a hydraulic ejection of concentrateswhich assists the normal removal of concentrates by gravity and shaking alone.

Another important object of the invention is to provide a machine adjustable to yield a concentrate of any desired specific gravity range.

A specific object of the invention is to achieve a machine capable of rapidly and economically concentrating classified monazite bearing sands at least 6 to 1 by weight while still retaining all the vaiuable minerals in the concentrate, including the thorium containing monazite.

Still another object of the invention is to achieve a concentrator wherein the ejection grooves will not become blocked by black sands, and other troublesome materials.

Anotherobject of the invention isto achieve economy of water, which is an important item in mining locations.

. She principal object of the invention is to still another object of the invention is to achieve a machine simple in operation and requiring a minimum of adjustments. These and other objects are achieved by the machine set forth in the drawings and more particularlydescribed hereinafter.

In the drawings, Figure l is a broken side elevation machine.

Figure of the is a partial rear elevation of the machine, showing in detail the agitating mechamsm;

Figure 3 is ,apartial front elevation, showing the front table and shaker bed mountings.

Figure 4 is a plan View of the top of the table. Figure 5 is a transverse cross section of the tabletop taken through line5-5. Figure 6 is a longitudinal projection of a transverse cross section of the tabletop taken through line 65.

Figure 7 is a cross section of eccentric drive shaft 4d taken through line '!7.

In the detailed description which follows, and in interpreting the drawings, it should be understood that the structural elements of the machine illustrated are of steel plate varying in thickness from inch to inch, and the rigid joints and seams are all welded so that the rapid vibration of the machine will not loosen the joints and dissipate any of the vibratory motion. The table i may vary considerably in size, though it should preferably not be more than about 40 x inches. I have found that much smaller tables thanthis are effective. The table comprises an elongated, rectangular bed-plate 2 of steel plate, which is divided functionally into three main sections. The rear, or upper portion from a to 19 comprises, with side walls 3 and 4, end wall 5, and baffle plate 6, a hopper i into which the wet pulp 'or placer is fed. The baflie plate extends down to within about an inch of the bed plate, providing a narrow slit 8 through which the ore is washed onto the second section of the tablefrom b to c, which, with the metal strips 9,,forms a bulliontrap which entr'aps very heavy minerals. The third and 11131301 section of the table, from c to (Z, forms with metal strips ill, the concentrating area where the concentrate is separated from the tailings. A gutter H is provided along the side Wall 3 to receive the discharged concentrate. An apron I2 and a deflector plate l3 are provided between the sections a.b and 22-0 for the purpose of transmitting the pulp onto the surface of the concentration table from the bullion compartment, and to keep it from flowing into the gutter i l. A cross bar M is provided just below the baffle plate for reinforcement.

The bullion compartment consists of a laterally levelsurface made up by elongated metal strips 9, uniformly rectangular in cross sectionand preferably of aluminum or aluminum alloy, which are riveted diagonally across the bed plate 2 at an angle sloping about l" from a lateral axis of the table. Thesestrips are preferably about 1 inch in width and about inch in height, and are spaced about inch apart to form trap grooves I 5. At their upper ends they abut the side wall 3 at an angle of 86, and their lower ends {terminate an inch or two short of side wall 4, proriding a cleaninggutter I6. A cleaning drain I! strips are riveted to the bed plate} contra-diagonally to the trap grooves 5, at an angle of about 21 from the lateral axis of the table, which is perpendicular to the pulp flow, and abut the side wall 4 at an angle of about 69. From the line e-e to a line an inch or two short of gutter II, the height of the strips iii above the bed plate 2 increases evenly from T35 inch to a maximum of /2 inch, as shown in Figures and 6. In this particular machine, I have found it convenient to form the tapered part of the strips separately from the level part, but they obviously may be made in one continuous strip, if convenient. These strips terminate about two inches from side wall 3 to form gutter I i.

It will be seen that the table surface formed by these strips is laterally level up to the line e-e. From the line e-e to the line of maximum height, a lateral distance of about 9 inches, the surface of the table rises inch. This corresponds to a lateral, upward slope of about 2 from the level area of the table.

In addition to the sloping table surface so formed, the plane of the floor of the ejection grooves or channels it formed between the strips I0, is also inclined upwardly at an even greater slope than the table surface from e-e to a line an inch or two short of gutter II. This is accomplished by riveting tapered, inch square aluminum bars l to the bed plate 2 between the strips Iii, from e-e to gutter II. The height of these bars above the bed plate rises evenly from nothing at e-e to inch at their maximum. The maximum height" of both the table surface and the channel floors above the bed plate 2 is reached about 2 inches from gutter M. It will be seen that at this line of maximum height, the grooves are only /8 inch in depth.

The apron I2 consists of adjoining aluminum strips riveted to the bed plate 2, and appropriately bevelled to provide a flush juncture with the surface of the concentration area.

A concentrate discharge chute 2!! is provided at the lower end of gutter I l.

The table i is mounted on shaker bed 2| at its front end through pivot bearings 22 welded to the table, and pivot shaft 23, journalled in pivot bearings 2 which are welded to the shaker bed. Toward the rear the table is mounted on shaker bed 2! through a pair of racks 25 welded to the table side walls 3 and i, paired pinions 2t welded to shaft 2: and paired detent dogs 28 welded to shaft 29. Shafts 2'! and 29 are journalled in bearings formed through shaker bed flanges 3E) and heavy steel reinforcements 3i welded to the inner side of the flanges 30.

The angle at which the table is tilted may be varied by turning adjusting wheel 32, which is welded to pinion shaft 21. Pinions 2s engage racks 25 and raise or lower the table when the ratchet dogs or detents 28 are disengaged from the racks. The detent dogs are rigidly engaged with the racks during operation by tighening lock bolts 33 which are threaded into support bars 34, which in turn are welded to flanges 36. Springs 35 are not essential to the locking mechanism, merely serving to yieldably engage the detent dogs with the racks while the elevation of the table is being adjusted. Rack supporting blocks 35 are provided behind each rack opposite pinions 25.

The racks 25 and the detent dogs 23, as well as the locking mechanism and support blocks, should be constructed of heavy steel members of sufficient strength to transmit efficiently the vibration of the shaker bed to the table. All the vertical motion and part of the longitudinal motion imparted to the table must be transmitted through racks '25. Some, and probably most of the longitudinal vibration imparted to the table is transmitted through the pivot shaft 23.

The shaker bed 2| consist of a heavy steel plate Bl, preferably /2 inch in thickness, with downwardly extending flanges 30 on each side, which may be of lighter material. If desired, the center portion of-the plate 31 may be cut away in order to conserve weight, provided a wide enough margin is left along the sides and ends to preserve rigidity. Beinforcements may be used if desired.

The shaker bed 2! consists of a heavy steel plate the front end through stationary shaft 39 welded to the shaker bed, double pivot bearings 40, and stationary shaft 15 welded to frame 38. The double pivot bearings it are held onto the trunnions of shafts 39 and ll by means of retaining collars d2, which are locked onto the shafts in known manner by means of set screws, not shown. The shaker bed is rigidly mounted to the frame at the rear through paired journal boxes 43 which are bolted securely to the rear of shaker bed plate 3i, eccentric drive shaft 44, and paired journal boxes 15 which are bolted securely to frame cross beams E16. The journal boxes iliand 45 house a conventional type of ball or roller bearings, which are not shown. Eccentric drive shaft 44 is held in position laterally by conventional retaining collars di.

The rear of the shaker bed 2! is also yieldably mounted to the frame 38 through paired springs 48 and spring mounts 49 which are welded to frame legs 59. These springs should be of heavy enough scale to support the full rear weight of the shaker bed and table, plus another inch or two of mounted deflection. The springs are mounted under more deflection than the weight of the machine parts mounted thereon normally provides. This is done in order that the upward thrust of the shaker bed will be sharper and faster than the downward return stroke. This action assists greatly the gravity settling of the heavier materials close to the surface of the table. The lighter materials are not as greatly affected, since they are largely water borne. In the present case, I have found that about a inch spring is required. These springs also serve the purpose of equalizing the upward and downward thrust on the drive shaft ed and bearings 43 and is.

The frame 38 is composed of steel 4 X 6- inch L-beams about inch thick, and welded together at all joints to form an elongated rectangular box. Obviously, any other type of strong, rigidly constructed frame would be suitable.

Driving mechanism Vibratory motion is imparted to the shaker bed 2! through the eccentric drive: shaft 44. This shaft is driven by motor 5! through belt 52 and V-belt drive wheel 53, keyed to shaft 44. The shaft itself is a solid steel rod about 2 inches in diameter at each end where it is journailed into frame mounted bearings 45, andthe central portion, which is journalled into shaker bed mounted bearings 43, is inch larger in diameter than the frame mountedextremities, and its axis is offset inch from the axis of the extremities. This offset 54 may begin and end at any point between the two outer bearings 45 and the two inner bearings 43. Each journal mounted in bearings 33 and 45 is ground very slightly oval to fit into the inner bearing races, which are also slightly oval.

races.

Type of motion One of the principal operative features of my invention which, in combination with the table design, distinguishes it from other machines, is the type of motion which is transmitted to the table. In the first place, I employ a very rapid and shallow vibration compared tomost concentrators. I preferably operate the drive shaft 44 at about 1000 R. P. M., and since the offset of the shaft axes is only inch, the whole vibration cycle is only 1% inch in stroke. I have found that in my machine, this rapid, shallow vibration provides a very rapid and efficient separation of concentrate, preventing the grooves from blocking and allowing the concentrates to reach the floor of the grooves.

Since the shaker bed 2| is freely mounted on the drive shaft at the rear, and laterally pivoted on shaft 39 and double pivot bearings 40 at the front, it is obvious that the rotation of the drive shaft will impart to the rear part of the shaker bed 2| and the concentration table I a longitudinal and vertical rotation. However, since vertical motion is not possible at shaft 39, this rotation becomes more and more elliptical progressing toward the front of the shaker bed, until, at the shaft 39, it becomes horizontally, longitudinally reciprocating. This variety of vibratory motion over different parts of the concentration table gives each groove slightly different concentrating effects, and makes the, table more versatile in handling various types and classified sizes of ore. i

The backward thrust of the table, opposite to .the pulp flow, would obviously compress a thin ribbon or prism of water against the lower wall and fioor of each channel where the concentrate stratifies. The slope of the groove, from the lateral table axis, causes this water to move sharply but briefly toward the concentrate discharge side of the table, thus hastening the ejection of the concentrate, which would move more slowly by gravity and shaking alone. Due to the longitudinal slope of the table, however, and the short stroke of the backward table motion, this hydraulic effect is very local and does not cause excessive ejection of water and tailings into the concentrate. The lateral slope of the table surface and the floor of the channels, as well as the decrease in the depth of the grooves from e--e to gutter i 1, form a longitudinal weir, as shown in Figures 5 and 6, which counteracts either wholly or partially, depending on the angle at which the table is tilted longitudinally, the tendency of the water in the grooves to flow into the gutter l I. The shear of the larger body of water flowing over the top of the grooves also tends to pull the water out of the grooves and toward the tailings discharge. The fact that the trapgrooves I5 are arranged contra-diagonally to the concentrate ejection grooves i8 also assists in This prevents any rotational slip of the journals on the bearing pulling or diverting the flow of water away from the concentrate discharge side of the table.

Operation In operation the table I is, as previously described, first tilted to the desired angle on pivot shaft, or hinge 23. This angle must be determined by experimentation, since such a wide number of variables is presented by different ores, but I have found that to recover concentrates of specific gravity about 7 and lower from monazite bearing sands, the table should tilt about 11 from the horizontal. The wet ore, for example a monazite bearing sand, which should be classified to contain no material larger than 1 5 inch, is fed into hopper 1. The slope and vibration of the table carries the sand under baflle plate 6 onto the bullion compartment, where the larger and heavier particles of specific gravity higher than about 7 are entrapped in the trap-grooves I 5, from which they may be periodically removed by cleaning, if desired.

The de-bullionized sand then flows over apron i2 onto the concentration area of the table, where the materials of specific gravity between about 3.5 and '7 are Stratified in the ejection grooves M3 by gravity and shaking, and are ejected into gutter I! as previously described. This concentrate contains virtually all the monazite and garnets contained in the ore, as well as very fine gold particles which escaped the trap-grooves I5. The concentrate flows down the gutter ll, through chute 28, into a suitable receptacle. The materials of specific gravity less than about 3.5 are ordinarily silicates of no great value, and due to their lightness, are more susceptible to water fiow than the heavier materials, and hence flow over the grooves and off the table at the lower, or discharge end, forming tailings.

By operating in the above manner I have found that monazite bearing sands classified through a 16 mesh screen may be concentrated 6 to 1 in one run over the table, and still retain in the concentrate nearly all the valuable materials, including thorium containing monazite. Moreover, this concentration is accomplished at the rate of pounds of feed material per minute. Thus, in one simple classifying, and one rapid concentrating run, a very substantial reduction and concentration of the raw, bank-run material is obtained, amounting to as much as between 60 and 200 to 1 by weight.

Milled ores, including refractory and free milling ores, may be treated in a similar manner to the above, except that the table elevation should be adjusted to obtain the desired reduction in volume, or specific gravity range of concentrate. It may be necessary to classify these ores to between about 30 and 100 mesh.

Ihave found that myjmachineis remarkably selective in picking out the concentrate desired. If the tailings from a particular run are reconcentrated at the same table elevation, practically noconcentrate is obtained. Conversely, a reconcentration of a concentrateat the same table elevation yields practically no tailings.

In the claims, when I refer to the lateral axis of the table, I mean, an axis perpendicular tothe general direction of pulp fiow, and to the sides of the table. 1

While I have described my invention in detail with respect to a specific machine, I do not intend to limit my invention to the precise details shrin s. -Tbe deat he traaemorcsma of pulp flow, into a in Vary slightly, and their longitudinal slope may vary somewhat; Also the longitudinal slope of the ejection grooves may vary from about to provided their depth and lateral slope from the table bed is appropriately adjusted. The angle at which the table is elev-atedis also an interrelated factor with the other variables, and can only be determined by experiment. The bullion trap, or trap grooves, may be omitted, if desired. 7

It is obvious that various modifications can be made in the details without departing from the spirit of the invention which I intend to include in the scope of the appended claims.

I claim:

1. An ore concentrating machine as described, comprising a longitudinaly inclined concentration table divided longitudinally, in the direction or, laterally level and a minor area sloping upwardly from said level area at an angle of about 2 therefrom, said tahle being grooved over its operative surface with ejection grooves extending diagonally across said table at an angle of between about 10 and about 25 from its lateral axis, means for adjusting the elevation of the upper end of said table, and means for imparting to said table a rapid, longitudinal shaking motion.

2. An ore concentrating machine as described comprising a longitudinally inclined concentration table divided longitudinally, in the direc ion.

of pulp flow, into a major, laterally level area, and a minor area sloping upwardly from said level area at an angle of about 2 therefrom, said table being grooved over its operative surface with grooves extending diagonally across said table at an angle of about 21 from its lateral axis, said grooves being of uniform depth over the level area of said table and slightly diminishing in depth over the sloping area of said table, means for adjusting the elevation of the upper end of said table, and means for imparting to said table a short, rapid vertical and longitudinal rotating motion at its upper end, and longitudirial, reciprocating movement at its lower end.

3; An ore concentrating machine as described comprising a longitudinally inclined concentration' table divided longitudinally, in the direction of pulp flow, into a major, laterally level area, and a minor area sloping upwardly from said lev'el area at an angle of about 2 therefrom, said table being grooved over its operative surface with ejection grooves extending diagonally across'said table at an angle of about 21 from its lateral axis, said grooves being about inch in depth over the level area of said table diminishing in depth over the sloping area of said table to a minimum of about inch, means for adjusting the elevation of the upper end of said table, and means for imparting to said table a rapid, vertical and longitudinal rotating motion at its upper end tapering to longitudinal, reciprocating motion of about inch stroke at its lower end.

4. A machine as set forth in claim 3 including means for accelerating the upward vertical movement of said table and decelerating the downward vertical movement thereof. 7

5. An ore concentrating machine as described comprising a longitudinally inclined concentration table divided longitudinally, in the direction of pulp flow, into a major, laterally level area and a minor area sloping upwardly from said level area at an angle of about 2 therefrom, said table beinggrooved-over-its operative surface with ejection grooves extending diagonally across said table at an angle of about 21 from its lateral axis, said grooves being about g inch in depth over the level area of said table, and diminishing in depth over the sloping area of said table to a minimum of about V inch, said table being pivotally mounted at its lower end to-a shaker bed, a pair of supporting racks secured laterally toward the upper end of said table, pinions engaging said racks and mounted on a transverse shaft journalled in bearings attached to said shaker bed,- an adjusting wheel attached to said pinion shaft, a pair of detent dogs adapted to rigidly engage said racks, locks adapted to hold said detent dogs in place, said shaker bed being mounted toward the front and through trunnions and double pivot bearings, and toward its rear end through an eccentric shaft and bearings, to a rigid frame, and op'erative means'for driving said eccentric shaft.

6. A machine as set forth in claim 5 including springs deflected between the rear part of said shaker bed and said frame, and adapted to accelerate the upward thrust of said shaker bed and decelerate the downward thrust thereof.

7. An ore concentrating machine as described, comprising a longitudinally inclined tableysaid table being divided laterally into an upper, minor area grooved over its operative surface with trap-grooves extending diagonally across said table at an angle of about 4 from its lateral axis, and a lower, major area, said major area being divided longitudinally into a major, laterally level concentration area, and a minor concentration area sloping upwardly from said level concentration area at an angle of about 2 therefrom,

said concentration areas being grooved over their operative surfaces with ejection grooves extending across said table contra-diagonally to said trap-grooves at an angle of about 21 from the lateral axis of said table, said table being pivotally mounted at its lower end to a shaker bed, a pair of supporting racks secured laterally toward the upper end of said table, pinions engaging said racks and mounted on a transverse shaft journalled in bearings attached'to said shaker bed, an adjusting wheel attached to said pinion shaft, a pair of detent dog's adapted to rigidly engage said racks, locks adapted to hold said detent dogs in place, said shaker bed being mounted toward the front end through trunnions and double pivot bearings, and toward its rear end through an eccentric shaft and bearings, to a rigid frame, and operative means for driving said eccentric shaft.

8. A machine as set forth in claim '7 including springs deflected between the rear part of said shaker bed and said frame, and adapted to accelerate the upward thrust of said shaker bed and decelerate the downward thrust thereof.

JOSEPH STEPHAN.

@ES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 533,362 La'mpert Jan. 29, 1895 632,892 Gammett Sept. 12, 1899 868,830 Algert Oct. 22,

1,088,685 Deister Mar. 3, 1914 1,548,536 Macartnery Au'g. i, 1925 2,155,235 Morgan Apr. 18, 1939 2,291,044 Kennedy July 28, 1942 Certificate of Correction Patent No. 2,496,025 January 31,- 1950 JOSEPH STEPHAN It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 4, line 24, strike out the words consists of a heavy steel plate and insert instead is mounted to frame 88 at; column 8, line 16, for front and read from end;

end that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 20th day of June, A. D. 1950.

THOMAS F. MURPHY,

Assistant Oommissioner of Patents.

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