EP0081087A2 - Method and device for separating bulk material according to density - Google Patents

Abstract

In a method for separating according to density bulk material consisting of a finely particled and coarsely particled first component of low specific weight and at least one second component of a higher specific weight, in particular ground rough coal, the fine portion (FK) of the first component is fluidised in a vibrator trough (1) with a gas (L) and flows off in one direction. The residual material (GK + P + B) is conveyed in the other direction. Finally, at least the coarse portion (GK) of the first component is separated off from the residual material. In order to simplify the separation off of the coarse portion in method terms, it is proposed that at least the separation off of the coarse portion from the residual material essentially having no further fine portion (FK) occurs by means of the directional vibrational movement of the vibration trough (1). In a device for carrying out the method, the required separating device is integrated according to the invention into the vibration trough. <IMAGE>

Description

The invention relates to a method for density separation of a bulk mixture of the type mentioned in the preamble of claim 1 above.

From DE OS 29 43 556 a method and a plant for the dry separation of pyrite from hard coal is known, in which the density separation system has an inclined vibrating trough which the denser material, ie. H. conveys the mixture of heavy pyrite, crushed mountains and coarse-grained coal in one direction and allows the fluidized fine coal to flow downwards. The residual material drawn off from the density separation stage can be subjected to a subsequent screening in order to separate the coarsely coarse coal compared to the pyrite or the crushed mountains. A separation of the carried mountains from the pyrite is also addressed in order to enable further utilization of the pyrite or the sulfur contained therein. For this purpose, the semolina is removed from the vibrating trough.

It is the object of the present invention to specify a method of the type mentioned, in which at least the removal of the coarse fraction of the first component, in particular the coarse fraction of the coal when treating ground hard coal, is facilitated.

This object is achieved by the features in the characterizing part of claim 1.

The directional oscillating movement of the vibrating channel, which is required to separate the fine fraction of the first component, is additionally used for the separation of at least the coarse fraction of the first component; when using a screening device for separating z. B. no special drive for the separation device is required.

The density of the pyrite is about 5 g / cm ³ ; that of the mountains about 2 - 2.5 g / cm ³ and that of the coal, depending on the composition, 1.2 - 1.7 g / cm.

These density values cause z. B. coarse coal grains with a diameter> 0.5 mm have about the same sinking rate as pyrite and salvage particles <0.5 mm. It was also found that the sulfur content of the residual material discharged from the vibrating trough into the separating device is dependent on the grain size of the discharged material, the sulfur content being very large at grain sizes of <0.5 mm and showing a clear drop down to grain size 0.8. Mountains were mainly found in the grain size range 0.5 - 1.0 mm, while the sulfur content is very small with a grain size> 1 mm.

For the separating device using the oscillating movement of the oscillating trough, it is therefore preferred that the residual material be sieved during the oscillating conveying in order to separate the coarse-grained coal. By integrating the sieve into the vibrating trough, the vibrations of the vibrating trough are used for sieving.

⁺ The grain size values can vary to a certain extent depending on the type or mixture of coal.

It was also found that, under the influence of the oscillating movement, a stratification consisting of essentially two layers occurs in the residual material drawn off from the outflow floor, the coarse-grained coal being located in the upper layer. Another way to separate the coarse fraction of the first component, i. H. the coarse coal is therefore preferably possible by stripping off the top layer of the vibrationally conveyed residual material, which essentially consists of the coarse fraction of the first component. Here, too, there is the advantage that the residual material is conveyed against the scraper by the oscillating movement of the oscillating channel.

Further subclaims relate to advantageous refinements of the method according to the invention.

The invention is also directed to a device for density separation.

For this purpose, the invention is based on a device according to the preamble of claim 6.

In order to make a device of this type suitable for carrying out the method according to the invention, it is provided that the separating device, viewed in the conveying direction of the residual material, is arranged in the vibrating channel directly behind the inflow floor.

Further subclaims relate to configurations of the device according to the invention.

• Figur 1 eine Schrägschwingrinne mit integrierter Siebeinrichtung einer ersten Ausführungsform;
• Figur 2 eine Schrägschwingrinne mit integrierter Siebeinrichtung einer zweiten Ausführungsform;
• Figur 3 eine dritte Ausführungsform mit integrierter Siebeinrichtung, bei der zwei Siebböden hintereinander angeordnet sind;
• Figur 4 eine dritte Ausführungsform mit integrierter Siebeinrichtung, bei der zwei Siebböden übereinander angeordnet sind;
• Figur 5 eine vierte Ausführungsform, bei der ein mechanischer Abstreifer am Ende eines Schwingbodens mit Abstand von demselben angeordnet ist;
• Figuren eine Ausführungsform, bei der ein keil-6 und 7 förmiger mechanischer Abstreifer mit pneumatischen Abstreifdüsen vorgesehen ist;
• Figur 8 einen Querschnitt durch eine weitere Ausführungsform der erfindungsgemäßen Vorrichtung, wobei auf der einen Längsseite der Schwingrinne ein mehrdüsiger pneumatischer Abstreifer und auf der anderen Längsseite eine Aufnahme für das abgestreifte Gut angeordnet sind.

The method according to the invention and the device according to the invention are illustrated by the attached figures explained in more detail. It shows:

• Figure 1 is an inclined vibrating trough with integrated sieve device of a first embodiment;
• Figure 2 shows an inclined vibrating trough with an integrated sieve device of a second embodiment;
• FIG. 3 shows a third embodiment with an integrated sieve device, in which two sieve trays are arranged one behind the other;
• Figure 4 shows a third embodiment with an integrated sieve device, in which two sieve trays are arranged one above the other;
• FIG. 5 shows a fourth embodiment, in which a mechanical scraper is arranged at the end of a vibrating floor at a distance therefrom;
• Figures an embodiment in which a wedge-6 and 7-shaped mechanical wiper with pneumatic wiping nozzles is provided;
• FIG. 8 shows a cross section through a further embodiment of the device according to the invention, a multi-nozzle pneumatic scraper being arranged on one long side of the vibrating channel and a receptacle for the stripped material being arranged on the other long side.

The vibrating channel 1 shown in FIG. 1 has an inflow floor 3 which extends over two air chambers 2 a and 2 b. The two air chambers are separated from one another by a web 4. The air chamber 2 a is pressurized with fluidizing air La of lower pressure and the air chamber 2 b with air La of higher pressure. A vibrating drive 5 engages on the vibrating trough 1, which can set the vibrating trough 1 in a directional swinging motion according to the micro-throwing principle. Such drives are known.

Seen in the conveying direction of the directed oscillating movement, a sieve plate 6 directly adjoins the inflow plate 3; To remove the sieve passage, the sieve chamber 6 located under the sieve bottom is provided with an outlet 8. Air chamber 2 b and sieve chamber 7 are separated from each other by a wall 9. The longitudinal walls of the chambers 2 a, 2 b and 7 are not shown in the schematic illustration.

When using this device for separating ground raw coal, it is applied to the inflow floor 3 in the form of a bulk material mixture consisting of finely divided carbon FK, coarse coal GK, pyrite P and mountains B. The fine-particle coal FK is fluidized by the fluidizing air L and flows to the left in FIG. 1, as shown by the arrow FK. The other components GK, P, and B are conveyed by the directional oscillating movement against the outflow direction of the fine coal FK, ie to the right in FIG. floor 6 promoted. The hole size in the sieve plate 6 is chosen so that the coarse coal GK remains on the sieve as residue, while the mixture P + B can be drawn off as sieve throughput. This is in the Figure represented by the arrows. In the areas given as preferred grain sizes in the introduction, the hole diameter in the sieve tray 6 should be in the range of 0.5 and 1 mm.

While in the embodiment according to FIG. 1, a dust plate 10 is provided on the right end of the sieve plate 6 in order to achieve a sufficient dwell time for the residual material GK + P + B on the sieve plate, it is also possible to dispense with the storage ledge 10 and for this purpose in FIG. 2 to use a sieve plate 11 with an upward inclination with respect to the plane of the inflow plate 3.

While the arrangements according to FIGS. 1 and 2 only allow the two coal components FK and GK to be separated from the bulk material mixture, the arrangement according to FIG. 3 enables the mixture P + B to be further separated into the individual components P and B. To this For this purpose, two sieve trays 12 and 13 are arranged behind the inflow tray 3, which participate in the oscillating movement of the oscillating channel.

In the case of the values discussed in the introduction to the description, the hole size for the sieve part 12 is in the range 0.5 and 0.8 and in the sieve part 13 in the range 0.7 and 1.0, ie a material falls in the sieve chamber 14 assigned to the sieve bottom 12 with a high proportion of pyrite P and in the sieve chamber assigned to the sieve plate 13 essentially mountains B, while the coarse coal GK is discharged as a sieve residue (e.g. Ø ₁₂ = 0.5 and Ø ₁₃ = 1.0).

In the arrangement according to FIG. 4, a sieve plate 16 adjoins the inflow plate 13, under which a further sieve plate 17 is arranged. The order is made such that the throughput of the sieve plate 16 consists essentially of mountains and pyrite, while the throughput of the sieve plate 17 consists of a material with a high proportion of pyrite P. The coarse coal GK is drawn off as residue from the sieve tray 16. In the preferred grain fractions, the hole size of the sieve bottom 16 is in the range of 0.8 - 1, ₀ mm, while the hole size in the sieve plate 17 in the range of 0.5 - 0.8 mm is, z. B. Ø ₁₆ = 1.0 and ⁰ 1 ₇ ⁼ 0.5 mm.

In the embodiment according to FIG. 5, an oscillating floor 18 adjoins the inflow floor 3. At the end of the oscillating floor, a wiper strip 19 is arranged at a distance from the oscillating floor 18. The scraper 19 is arranged at a distance S from the vibrating base 18, which essentially corresponds to the layer thickness of the layer P + B which is established on the vibrating base. When the device is in operation, the mixture P + B is therefore pushed into the outlet 20, while the layer above it, which consists essentially only of coarse coal GK, is stripped off by the scraper 19, as is shown schematically by the arrow GK in FIG .

In the embodiment according to FIGS. 6 and 7, a wedge-shaped scraper 21 extends above the oscillating floor, the tip of which is directed towards the inflow floor. This scraper pushes the coarse coal GK into two receiving pockets 22 arranged laterally on the shaking trough, with inlet edges 22 a raised relative to the vibrating floor. To support the wiping action, the wiper 21 is provided with nozzles 21 a, which are acted upon by gas via a compressed gas supply line 21 b. The below the layer of pyrite P and mountains B passing through the stripper enters a trigger 23.

The distance between the scraper strip 19 and the scraper 21 from the vibrating floor can be changed depending on the coal quality.

In the embodiment according to FIG. 8, which shows a section transverse to the direction of vibration of the conveyor trough 1, a purely pneumatic scraper is used. Lateral scraper nozzles 24 lie approximately in the middle of the layer of coarse coal which arises during operation and drive the coarse coal GK into a receptacle 25 arranged on the other longitudinal side, while pyrite P and mountains B are conveyed perpendicular to the plane of the drawing. (It is also possible to use nozzles arranged in the middle and blowing on both long sides.)

It is also possible in the embodiments according to FIGS. 5-8 to use a sieve plate comparable to a sieve plate 12 or 17 instead of a closed oscillating plate 18, so that mountains B are drawn off via the outlets 20 and 23 and a corresponding outlet in FIG. 8, while as a throughput material with a high pyrite content is obtained from the sieve bottom and is deducted accordingly.

Instead of perforated sieve trays, sieve nets can of course also be used. A horizontal vibrating trough can also be used as the vibrating trough. The pneumatic wiper nozzles 21 a and 24 can be connected to the fluidizing gas source.

Finally, it should be noted that the grains of the coarse coal GK can consist essentially of pure coal and / or coal with adhesions.

In the embodiment according to FIG. 1, more than two chambers 2 a and 2 b in the longitudinal direction of the channel are also possible in order to achieve a more uniform increase in the amount of fluidizing gas in the conveying direction of the residual material.

Claims (12)

1. A method for density separation of a bulk material mixture consisting of a finely divided and coarse first component of lower specific weight and at least one further component of higher specific weight, in particular for density separation of ground raw coal, in which the fine component of the first component is fluidized in a vibrating trough with a gas and flows off in one direction and the residual material is conveyed in the other direction and in which at least the majority of the first component is separated from the residual material,
characterized,
that at least the separation of the coarse part from the residual material which essentially no longer has a fine fraction of the first component takes place by means of the directional oscillating movement of the oscillating channel. 2. The method according to claim 1,
characterized,
that the residual material is screened during the vibration promotion. 3. The method according to claim 1 or 2,
characterized,
that essentially the top layer consisting of the coarse portion of the first component of the vibration-conveyed residual material is stripped off. 4. The method according to claim 3,
characterized,
that the stripping is done mechanically and / or pneumatically. 5. The method according to claim 3 or 4,
characterized,
that stripping is carried out with a stripping force component transverse to the direction of vibration. 6. The method according to any one of claims 1-5,
characterized,
that the amount of fluidizing gas acting on the bulk material increases as seen in the conveying direction of the residual material. 7. A device for density separation according to one of claims 1-6 with a vibrating trough including a drive for generating a directed oscillating movement and a gas-permeable inflow floor and with a downstream separating device for separating different grain fractions,
characterized,
that the separating device (6; 11; 12, 13; 16, 17; 19; 21; 24) in the conveying direction of the residual material (GK + P + B) is arranged in the vibrating trough (1) directly behind the inflow floor (3). 8. The device according to claim 7,
characterized,
that the separating device is a sieve device with at least one sieve (6; 11; 12, 13; 16, 17). 9. The device according to claim 7,
characterized,
that the separating device is a scraper device with at least one mechanical and / or pneumatic scraper (19; 21; 24) and the scraper is arranged at a distance (S) from an oscillating floor (18) assigned to the scraper. 10. Device according to one of claims 7-9,
. characterized,
that the separating device has at least two screens (16, 17; 12, 13) arranged one above the other or one behind the other. 11. The device according to one of claims 7-10,
characterized,
that under the inflow floor (3) more than one air chamber (2 a, 2 b) is formed. 12. The device according to claim 11,
characterized,
that the chambers with different fluidization gas pressures (L 1, L 2) can be acted upon.

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