Helical Ore Concentrator

Abstract

An apparatus for concentrating ore and the like material having two chutes joined by a ridge-shaped portion and running in adjacent parallel relation and helically about a substantially vertical axis. The outer chute carries a mixture of a liquid and the material to be concentrated, and the inner chute carries the liquid by means of which the concentration is effected, the liquid being transferred from the inner chute to the outer chute by the centrifugal force. A groove is arranged in the ridge-shaped portion. A band which may have through holes is inserted in the groove and its projection from the groove is adjustable. The band serves as an adjustable overflow to enable precise control of the transfer of the liquid from the inner chute to the outer chute at successive portions along the length of the chutes.

Description

U.S. Pat. No. 2,700,469, British Pat. No. 718,353 and Swedish Pat. No. 198,704 disclose an ore concentrator which has two chutes running in adjacent parallel relation and helically about a substantially vertical axis, said chutes being interconnected by a ridge-shaped portion and the outer chute being intended for the material to be concentrated which flows downwardly in said chute, while the inner chute is intended for the liquid by means of which concentration is effected and which flows downwardly in said chute and by the centrifugal force is successively transferred to the outer chute. The material to be concentrated is in the form of a suspension of pulverulent or granular material in a liquid, and during the downward flow of the suspension along the helical outer chute there takes place a separation of a concentrate of higher specific gravity. This concentrate is discharged through openings disposed at intervals along the inner edge or lip of the outer chute. On the other hand, the material of the suspension having a lower specific gravity is forced by the wash liquid to flow along the outer edge or lip of the outer chute, and this material gradually is discharged at the lower end of the chute.

In the apparatus described above the wash liquid flowing in the inner chute is passed over into the outer chute with the aid of connecting passages or sluiceways distributed throughout the length of the chute. The positions of these passages or "water pickups" must be determined, however, already at the manufacture of the concentrating apparatus. For this reason said prior art concentrating apparatus cannot be set for concentration of different types of ores since the optimum positions of the pickups are dependent upon the difference between the specific gravity of the concentrate and that of the gangue. Another disadvantage of the prior art concentrating apparatus is that it provides very restricted possibilities of finely adjusting the flow of the wash liquid over into the concentrating chute during use of the apparatus.

The object of the present invention is to overcome the above disadvantages and thus to provide a concentrating apparatus which can be set for concentration of various raw materials and which permits adjustment in operation for attaining optimum operating conditions. These desiderata are satisfied by providing in the ridge-shaped portion between the adjacent parallel chutes a groove extending along said chutes, and by inserting into said groove a band in the form of one or more parts which partially project from said groove.

The invention will be more fully described in the following with reference to the accompanying drawings in which:

FIG. 1 is a perspective view of approximately one turn of a concentrating apparatus according to the invention;

FIG. 2 is an elevational view of a chute section in said apparatus;

FIG. 3 is a plan view of the chute section shown in FIG. 2;

FIG. 4 is a section on line IV-IV in FIG. 3; and

FIG. 5 is a view of a detail of the apparatus, showing various embodiments of holes therein.

The concentrating apparatus has two chutes 10 and 12 running in parallel relationship. These two chutes are interconnected by a ridge-shaped portion 13 and extend helically about a substantially vertical axis. The interconnected chutes 10, 12 are divided into sections 11 each constituting approximately one-third of a turn of the helical chutes. In the outer chute 10 there is an outlet 14 at the lower end of each chute section 11. This outlet 14 is connected by means of a hose 15 to a centrally positioned vertical pipe 16 which serves as a discharge passage for the concentrate separated in the apparatus. The material to be concentrated, which is in the form of a suspension, and the wash liquid necessary for the concentration are supplied in a known manner at the upper ends of the chutes 10 and 12, respectively, and flow downwardly along their respective chutes. The chute 12 is so designed that the wash liquid during its downward flow in the chute 12 will successively be transferred to the chute 10 by the centrifugal force. This transfer to the chute 10 can be furthered by the provision in per se known manner of pickups 17 on a level with the outlets 14.

According to the invention, a groove 18 is formed in the ridge-shaped portion 13 between the two chutes 10 and 12. Said groove extends helically as do the two chutes and serves to receive a band 19 which is in one or more parts and partially projects from the groove 18. The band 19 can be solid, but as is the case in the embodiment shown in the drawings, can also have one or more through holes 20 therein. The configuration of these holes can vary, and FIG. 5 shows some possible hole configurations. The band 19 may be of natural or synthetic rubber, plastic material, sheet metal or any other suitable material.

During use of the apparatus the wash liquid 21 flows downwardly through the inner chute 12, and by the centrifugal force (and also by the intermediary of the pickups 17) the wash liquid flows up along the said wall of the chute 12 onto the upper side of the ridge-shaped portion 13. The wash liquid then flows on the upper side of the portion 13 along the band 19 until the liquid reaches the hole or holes 20. The wash liquid passes through the holes 20 and enters the chute 10 where it flows in a spiral path flushing the material 22 towards the outer wall of the chute 10. During its downward travel along the chute 10 the material 22 is divided into a heavy fraction and a lightweight fraction, the heavy fraction flowing downwardly within the inner half of the chute 10 and the lightweight material flowing downwardly along the outer half of the chute 10. The heavy material, the concentrate, is discharged from the chute 10 through the aforementioned outlets 14, and to cause the concentrate to flow for sure up to the outlets 14 a guide wall 23 is arranged in the chute 10 on a level with each outlet 14.

If the band 19 is solid or imperforate the wash liquid on the upper side of the ridge 13 will flow downwardly along the band 19 until it reaches a point of the band where the latter projects from the groove 18 by so small an amount that the liquid can flow over it; the band in this case serves as an overflow. This embodiment of the concentrating apparatus according to the invention is the most advantageous if heavily contaminated water is used as wash liquid, as is often the case in the concentrating plants of mines. For it has shown that impurities in the wash liquid can easily clog the connections between the two chutes in the prior art concentrating apparatus as well as the holes 20, if any, in the band 19.

By reason of the vertical adjustability of the band 19 it is possible within broad limits to vary the transfer of the wash liquid from the chute 12 to the chute 10, and a still greater number of variations is provided if a perforated band 19 is selected, for in that case variations can also be attained by changing the configuration of the holes 20. By reason of the vertical adjustability of the band 19 it is also possible fully to close the supply of wash liquid to the chute 10 at such points where no wash liquid is desired. If the band 19 is solid such closure is realized by pulling the band 19 so far out of the groove 18 that the wash liquid is incapable of flowing over the top edge of the band, and if the band 19 is imperforate the closure is realized by pressing the band so far down into the groove 18 that the hole or holes 20 will be situated entirely within the groove 18. By control of the position of the band 19 in the groove 18 one can thus adjust the desired amount of wash liquid very exactly within each individual section of the concentrating apparatus. Further variations are possible by inclining the groove 18 and as a consequence the band 19 inwardly or outwardly in relation to the chute 12, the transfer of the wash liquid from the chute 12 to the chute 10 being rendered more difficult if the groove and the band are inclined towards the chute 12, and easier if the groove and the band are inclined towards the chute 10.

The band 19 should be divided into such lengths that full adjustability is provided at each outlet 14. The joint proper between the different lengths of the band 19 can be an overlap joint or a butt joint between the band end surfaces.

As will appear from FIGS. 2--4 each chute section 11 is formed as a two-layer construction, the inner layer 24 consisting of natural or synthetic rubber and forming the inner side of the chute 10, the ridge 13 and the entire chute 12. The outer layer 25 may be made of for instance reinforced plastic and serve as a supporting structure for the chute 10. The inner layer 24 extends over and downwardly along the end flanges 26 of the section 11 so that upon assembly of the various chute sections the inside of the chute will be formed entirely of rubber.

Claims

I claim:

1. An apparatus for concentrating and separately collecting from a comminuted mass composed of particles having different specific gravities those particles having like specific gravity, comprising two chutes (10, 12) running in adjacent parallel relation and helically about a substantially vertical axis, a ridge-shaped portion (13) extending between and interconnecting said chutes, said outer chute (10) being adapted to carry a stream of liquid having therein the material to be concentrated and said inner chute (12) being adapted to carry a stream of liquid by means of which concentration is to be effected and which flows downwardly in said inner chute and by the centrifugal force is successively transferred to said outer chute, means defining a groove (18) in said ridge-shaped portion (13) between the adjacent parallel chutes (10, 12), said groove-defining means extending along said ridge-shaped portion, band means (19) inserted for vertical adjustment in the groove (18) in said groove-defining means, said band means having at least one part which partially projects from the groove in said groove-defining means, and drawoff outlets (14) in the bottom of said outer chute (10) said drawoff outlets being arranged periodically along the length of said outer chute and adjacent the inner edge thereof.

2. An apparatus as claimed in claim 1, wherein said groove-defining means and said band means (19) are inclined inwardly in relation to said inner chute (12).

3. An apparatus as claimed in claim 1, wherein said groove-defining means and said band means (19) are inclined outwardly in relation to said inner chute (12).

4. An apparatus as claimed in claim 1, wherein said groove-defining means forms a smooth surface at the top of said ridge-shaped portion (13).

5. An apparatus as claimed in claim 1, wherein said band means (19) has means defining at least one through hole (20).

6. An apparatus as claimed in claim 5, wherein said hole-defining means defines at least one longitudinal slot-shaped hole (20).

7. An apparatus as claimed in claim 5, wherein the depth of the groove (18) in said groove-defining means is such in relation to the position of said at least one hole (20) in said hole-defining means that said at least one hole is located entirely within the groove (18) when said band means is located as deeply down as possible in the groove.