US2081182A - Apparatus for ore separation or concentration - Google Patents

Description

May 25, 1937. s. MALKE'ET m.- 2,081,182

' APPARATUS FOR ORE SEPARATION 0R CONCENTRATION Filed Marh 1:5, 19:55

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, INVENTORS.

Sven Malke and Eric Alfjellgren WKQM ATTQRNEY.

45 The front and the back plates of the accelerator machine. Fan action by the accelerator wheel is 45 Patented May 25, 1937 4 UNITED STATES PATENT OFFICE APPARATUS FOR ORE SEPARATION OR CONCENTRATION Sven Malke, Milwaukee, and Eric A. Kjellgren,

West Allis, Wis.,' assignors to A. O. Smith Corporation, Milwaukee, Wis., a corporation of New York Application March 13, 1935, Serial No. 10,756

2 Claims. (Cl. 209120) This invention relates to improved apparatus there is an extension which extends for some disfor use in ore concentration or separation and tance in the direction of rotation of the wheel, specifically to apparatus of this kind for the as shown at 20. This extension serves to prevent treatment of dry ores. escape of material through the open front plate In the art of ore separation it has been heretoof the wheel and may, if desired, be extended all 5 fore proposed to project ore through the air to the way around the circumference with the exeffect a preliminary classification of the ore and ception of an opening for the feed pipe Ill. The

to screen or otherwise treat the material thus feed pipe should preferably be so arranged that classified to separate the valuable material from the feed is directed somewhat to the forward side other material with which it may be mixed. of the point at which the belt coming from the in An object of this invention is to provide rear pulley first makes contact with the acceleraan improved apparatus for projecting ores for tor wheel. When this is done the outer surface of usein connection with such methods of separathe wheel is sealed against the escape of material tion. 7 before it reaches the point to which the feed is Other objects of the invention will be clear from directed, and no material is fed between the belt 1.. the accompanying detailed description and the and the wheel Where its presence would result in drawing in which: wear of the belt or of the wheel, or of both. While Figure 1 is a longitudinal elevation of the ap-- this arran ement f he f d pi is preferred f r paratus in which parts are shown in section; the reasons given, it is not indispensable that it Fig. 2 is a vertical section taken on the lin be so arranged- E n When t feed p p is S0 20 22 of Figure 1; and located as to discharge a moderate distance be- Fig. 3 is an enlarged view of a portion of the hind the point at which the belt coming from the accelerator wheel. rear pulley makes contact with the accelerator Referring to the drawing, the shafts I and 2 wheel, the vanes have a tendency to direct the are supported in bearings 3 and 4 respectively by feed forward before it reaches the outward pesuitable pedestals 5 and carry the pulleys 6 and I p y 0 the Wheel d to P v y S respectively. The pulley 6 is rotated in the direetial difficulties due to feed being trapped between tion indicated by the arrow by an electric motor the belt and the wheel. or some other suitable driving means not shown A guard 2| y be mounted to Cover most 0 in the drawing. A continuous belt 8 passes that portion of the accelerator wheel which is not around the pulleys 6 and "I and under anaccelerin contact with the belt 8. A narrow opening 22 is. ator wheel 9. The accelerator wheel 9 is mount d left uncovered for the egress of material fed into on shaft II which rotates in bearings l2 and [3 the accelerator wheel. While a guard or hood is "supported on suitable pedestals I4. The acceleranot indispensable Since even in s absen e the tor wheel may conveniently be an idler wheel greater part of the material fed into the wheel which is driven by the friction of the belt as shown lies smoothly on the belt 8 and is o d y t in the drawing. The accelerator wh l 9 may the guard does prevent asmall amount of material be composed of a front plate l5 nd b k plate from being thrown oil in difierent directions and I6 flanged outwardly at H t rovid for tt his, therefore, a desirable addition. Furthermore, ment to the shaft l l and at l8 to provide a b with high belt speeds the accelerator wheel is ro- --HI ing for the belt 8, The front plate [5 i open t tated rapidly and tends to act as a fan drawing the center for the introduction of a feed pipe l0 a in U e Central Op in the front to feed ore into the open space between the front p t and exhausting it a the p p y Whe e and the back plates. it may carry with it dust from the ore fed into the wheel are rigidly connected together by .vanes l9 further undesirable in that it sets up air currents which support the front plate. Flat vanes may be which interfere to some extent with the uniform used and set radially or at an angle to th r diu motion of the stream of particles which is thrown or curved vanes may be used with the inner porfrom the moving belt. The guard substan ia y tion bent forward in the direction of rotation of eliminates any fan actionthe wheel, as indicated in the drawing, in order While the outside guard or hood'Zl is pr a y that ore fed through the spout or feed pipe [0 the most effective means for the elimination of into the space between the front and back plates fan action by the accelerator wheel, and also of the accelerator wheel may be more readily serves the additional purpose of confining any 55, forced to its periphery. In front of the feed pipe material which may be thrown off by the upper portion of the wheel and returning it to be fed onto the belt, the fan action may also be substantially eliminated by carrying the extension 20 of the feed pipe all around the circumference with the exception of an opening for the entrance of the feed pipe. This substantially closes the inner portion of the accelerator wheel and prevents the vanes from drawing air from the center and forcing it out. As an alternative to this construction, the front plate of the accelerator wheel may be entirely closed except for an opening in which the feed pipe is arranged so as to make a tight fit, or the feed pipe may be passed through a stationary plate mounted close to the front of the revolving accelerator wheel and arranged so as to seal the opening in the front plate.

It is preferable that the belt 8 make contact with the accelerator wheel over a substantial are instead of having a practically straight belt with which the accelerator wheel is in contact for only a short distance. When the belt is in contact with the wheel for a considerable arc, it is clear from the drawing that the belt running onto the' accelerator wheel from the rear pulley I will seal the outside of the space between the front and back plates of the wheel, and will form, with the vanes [9, small pockets which are closed except on top. The pockets remain closed. on the bottom until the belt leaves the accelerator wheel. The are fed into these pockets from above by the feed pipe I0 is brought up to the belt speed by the action of the vanes l9, and leaving the pockets at the belt speed when the belt departs from the accelerator wheel, is carried along by the belt without further acceleration. I

In such a device it is also important that there be only a relatively short length of belt between the accelerator wheel and the forward pulley 6, or if there be a long length of belt, that it be suitably supported or guided so as to cause it to run true and straight. With a long run of unsupported belt between the accelerator wheel and the forward pulley it is found that vibrations of the belt are likely to occur and that these cause the stream of particles to be projected at varying angles. This results in undesirable irregularity ln the operation of the machine. I

In the operation of this machine for the separation or concentration of ores, the pulley 6 is rotated in the direction indicated by suitable means and the ore to be treated is fed into the upper end of the feed pipe "I. Passing through the feed pipe the ore passes between the vanes IS in the accelerator wheel and reaches the belt 8. Since the ore is brought up to belt speed by the vanes l9 while passing through the accelerator wheel it lies smoothly on the belt and moves along with it until it is projected through the air as indicated at 23.

The ore which is treated with this apparatus may be all of one size or may be a mixture of different sizes. In case the ore has been screened before feeding to the machine so that it consists of a closely sized material, the particles of different substances travel a different distance I through the air depending upon their density and can be collected in separate piles. Each particle as it travels through the air is retarded by the resistance of the air to its motion and for particles of equal size those of low density travel a shorter distance from the machine before falling to the ground than those of a high density. Thus particles of valuable minerals such as separate the particles of the heavier and more valuable minerals from lighter materials to which they may have been attached when taken from the ground. The entire mass is then fed into the machine and projected through the air. In this case the feed will contain particles of a wide variety of sizes, both of the mineral which it is desired to separate and of the material from which it is desired to separate it. In the treatment of sand containing gold it can be assumed that the only materials which need consideration are gold and sand. When the ore is projected through the air the small particles of sand travel only a short distance before falling to the ground, while the progressively larger particles of sand fall progressively farther from the machine. A similar situation holds for the gold particles, the larger ones falling farther from the machine than the smaller ones. If the smallest gold particle is sufficiently large and the'largest sand particle is sumciently small, a substantially complete separation may be effected simply by passing the material through the machine, the smallest gold particle falling farther from the machine than the largest sand particle. In general it will be found, however, that this favorable condition is not obtained and that both sand and gold particles will be found together in some of the material collected after it has been thrown from the machine. In that portion of the material which falls at a specified distance from the machine, however, the gold particles will be smaller than the sand particles with which they are associated and can be separated from them by screening, or by some other method for the separation of particles of unequal size.

Furthermore, it has been found in the treatment of certain ores containing gold that the material which falls anywhere within a certain distance from the machine consists almost entirely of sand and contains substantially no gold. This material can therefore be discarded and requires no further treatment for the separation of gold. With this ore and a belt speed of about two thousand feet a minute, it has been found that the, material which falls closest to the machine and contains so little gold that it can be discarded, amounts to some forty per cent of the entire weight of the material treated. At higher belt speeds it appears that an even larger proportion of the entire mass contains substantially no gold and can be discarded without further treatment.

While equally favorable conditions may possibly not be found to exist in the treatment of other ores, there should, in all cases, be a certain amount of material which contains substantially no gold after being projected through the air with this machine. Such material need not be subsequently treated, and it will, therefore, in general be found moreadvantageous to first pass the crushed and disintegrated but unsized ore through this machine, and then separately treat the fractions which fall at different distances from the machine to separate the gold particles from the larger sand particles with which they fall, than to first size the entire mass of oreand to then separately pass the various sized fractions through the machine in order to obtain a substantially complete separation of the gold from the sand particles. In the second case, the entire body of ore is subjected to a sizing operation and is also passed through the apparatus of this invention; in the first case the entire body of unsized ore is passed through the machine, but only a portion is subjected to a sizing operation.

a In sizing the different fractions that are collected at diiferent distances from the machine when the unsized ore is passed through thescreen, the fraction which falls just beyond the fraction which contains substantially no gold is the one which contains the smallest particles of gold. This fraction should, therefore, be screened with a small mesh sieve. The small particles of gold fall through the sieve openings and form the concentrate from this fraction of material. The larger sand particles are caught on the sieve and discarded. The fractions which fall progressively farther away from the machine contain progressively larger gold particles and are treated with sieves or screens of progressively increasing screen openings.

The number of fractions of material which are separately screened will depend upon the results which it is desired to obtain. Since the material thrown from the machine is distributed over the entire distance from the machine up to the greatest distance reached by any particle; any desired number of fractions can be collected.

When a large number of fractions are taken, each fraction. or at least certain fractions,,will contain material which has been collected over a narrow range of distance from the machine. with a small number of fractions, on the contrary, there must be some fractions in which the material has been collected over a considerable range of distance from the machine. The separate collection and screening of a large number of fractions, using screens with different size screen openings, is conducive to both a high degree of concentration and a high degree of recovery of the valuable constituent in the ore. The separate collection and screening of a smaller number of fractions is likelyto lead to a lower degree of concentration if a high recovery is maintained, or to a lower recovery if a high degree of concentration is maintained.

While this apparatus has been specifically described in connection with its use for the concentration of ores it is to be understood that it may also be employed for the concentration of other substances, and the separation of a material of one density from a material of different density which is mixed with it.

1. In an apparatus for the concentration of ores, the combinationof a belt, an accelerator wheel in contact therewith and having radially extending openings through its periphery, said belt being adapted to close the openings in the rim of said wheel over the area in which it contacts with the wheel, and a stationary feed pipe to feed ore radially outwardly into the openings in the rim of the accelerator wheel, said feed pipe being provided with an extension forward in the direction of rotation of the wheel to close the inside of the openings in the rim of the ac celerator wheel for a substantial distance.

2. In an apparatus of the class described, the combination of a belt, an accelerator wheel in contact therewith and having radially extending openings through its periphery, and a stationary feed pipe to feed material radially outwardly into theopenings in the rim of the accelerator wheel, said feed pipe being provided with an extension forward in the direction of rotation of the wheel. to close the inside of the openings in the rim. of

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