RU2613917C2 - Powders granulation method and equipment for its implementation - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: fine powder is pre-compacted, compressed, comminuted (crushed), the obtained forms (pellets, strips, ribbons, tiles, plates) are rubbed through a sieve and additional balling of the obtained compacted fine powder is performed using uncompacted powder. The method is also implemented by means of equipment for method implementation comprising successively installed feeding pre-compression set screw, mill or roller press with pressing rollers, knife grinder, rubbing sieves, plate or tubular granulator.

EFFECT: obtaining of spherical granules retaining treated powder composition, and obtaining of granules with hardness of not more than 100 grams measured as per ASTM D5230 standard.

17 cl, 3 dwg

Description

The invention relates to the chemical industry, and in particular to granulation of powders, for example zinc oxide, eliminating the dusting and sticking inherent in powders in equipment.

A known method of wet granulation of powders, which consists in the fact that the powder located on the rotating surfaces of a dish-shaped or tubular granulator is wetted with a binder and doused with the formation of spherical granules [Chemical Encyclopedia. - M .: Soviet Encyclopedia. Ed. I.L. Knunyantsa, 1988., p. 1188].

However, the use of a binder can lead to a change in the chemical composition of the granulated powder, which is unacceptable.

The closest to the implementation and the achieved result is a method of dry granulation of powders [Chemical encyclopedia. - M .: Soviet Encyclopedia. Ed. I.L. Knunyantsa, 1988., p. 1188], which consists in the fact that the pre-compacted powder is pressed, for example, between the rollers (rollers) of the press into briquettes, tiles or strips, which are then crushed with knives and rubbed on sieves. In this case, granules of irregular shape of various sizes and dust are formed. The dust is returned to the feed hopper of the granulator for re-granulation.

Equipment for its implementation consists of the following devices: pre-pressing screw, roller or roller press, chopping knives, wiping sieves and transport devices.

The method and device for its implementation do not allow to obtain spherical granules, which are needed, for example, to ensure maximum flowability and minimum abrasion during transportation due to the absence of protruding parts. The high hardness of the particles obtained by repeated pressing of compacted dust limits the scope of granules.

The technical result of the proposed method and device is to obtain spherical granules with preserving the composition of the processed powder.

The technical result is also the production of granules with a hardness of not more than 100 grams, measured according to ASTM D5230.

The technical result of the proposed method of granulating powders is achieved by the fact that the powder is pre-compacted, pressed, crushed (crushed) obtained forms (briquettes, strips, ribbons, plate tiles), wiped through one or more screens to obtain particles of a certain size (calibration) and additionally carried out pelletizing the resulting compacted powder with a loose powder.

Pre-compaction can be carried out by a screw.

The compacted powder can be pressed with a roller or roller press with a rotational speed of the rollers or rollers from 10 to 100 rpm (depending on the diameter and the required productivity), with a pressing force of 10 to 60 kN.

Crushing can be carried out using a knife chopper.

Calibration of the resulting briquettes or strips can be carried out by wiping them through a sieve with a cell from 1.5 to 5 mm.

Pelletization can be carried out on a plate granulator with a plate rotation speed of 10 to 40 rpm, a plate diameter of 0.5 to 3 meters, a shoulder height of 0.2 to 1 meter, with a plate rotation axis inclined with respect to the horizon, at an angle of 10 to 55 degrees.

Pelletizing can be carried out on a tubular granulator with a pipe rotation frequency of 10 to 40 rpm, a pipe diameter of 0.3 to 3 meters, a pipe length of 1 to 15 meters, an angle of inclination of the axis of rotation of the pipe relative to the horizon from 1 to 45 degrees.

Uncondensed powder is added preferably in an amount of from 5 to 95% of the loaded mass.

After rolling, if necessary, it is possible to sort the finished granules, for example, by dispersing them on vibrating screens.

The difference of the proposed method from the prototype is the rolling of compacted, compressed and ground powder uncompressed powder.

The technical result is also achieved by equipment for implementing the method, including successively installed: feed pre-pressing screw, one or more roller or roller presses with pressing rollers or rollers, knife chopper, wiper sieves, plate or tube granulator.

In a preferred embodiment, the wiper sieves have cells of 1.5 to 5 mm.

In a preferred embodiment, the axis of rotation of the plate is inclined relative to the horizon by an angle of 10 to 55 degrees, the diameter of the plate is from 0.5 to 3 meters, the height of the shoulder is from 0.2 to 1 meter.

In a preferred embodiment, the angle of inclination of the axis of rotation of the pipe relative to the horizon is from 1 to 45 degrees, the diameter of the pipe is from 0.3 to 3 meters, the length of the pipe is from 1 to 15 meters.

The equipment may contain sorting sieves for separating the obtained granules into fractions.

The equipment may include transport and packaging devices.

The difference of the proposed equipment is that it includes a plate or tubular granulator for rolling the compacted, pressed and crushed powder uncompressed powder.

In FIG. 1 presents a diagram of the equipment containing a plate granulator, where 1 is a conical auger pre-pressing; 2 - pressing rolls (rollers); 3 - knife choppers; 4 - wiping sieves; 5 - plate granulator.

In FIG. 2 is a schematic diagram of an equipment comprising a tubular granulator, where 1 is a conical pre-press screw; 2 - pressing rolls (rollers); 3 - knife choppers; 4 - wiping sieves; 6 - tubular granulator.

The equipment operates as follows. The powder is fed with a cone screw (1) into the pressing zone, and the powder is pre-compacted. Next, the pre-compacted powder enters between the press rolls (rollers) (2), where the powder is pressed into strips, tiles or briquettes. Then strips, tiles or briquettes of pressed powder are crushed with knives (3), and then wiped through a sieve (4). The resulting mass enters a disk granulator (5) or a tubular granulator (6), where spherical granules are rolled when an uncompressed powder is added.

If it is necessary to separate the granules according to the given sizes, the granules are sorted, for example, on sorting vibrating screens. Granules larger than the specified size are returned to the wiper sieves, and granules smaller than the specified size are returned to the plate or tubular granulator, granules of the specified size are fed to the packaging.

A process diagram is shown in FIG. 3.

Below are examples of the method using the proposed device.

The starting material is TyreQuality STO 76967236-001-2011 zinc oxide powder.

Example 1. Equipment operation mode:

- The pressing force on the rollers of the roller press is 15 kN;

- The diameter of the rollers - 0.45 m;

- Roller rotation frequency - 20 rpm;

- Wiping sieve with a cell - 1.5 mm;

- Diameter of the plate - 0.9 m;

- The frequency of rotation of the plate - 33 rpm;

- The angle of the plate - 40 degrees .;

- The height of the pile plate - 0.25 m;

- The amount of added unconsolidated powder of zinc oxide is 50% by weight of the load.

Results:

Received spherical granules with a diameter of:

More than 5 mm 4.2% More than 3 less than 5 mm 11.7% More than 2 less than 3 mm 56.4% More than 1 less than 2 mm 24.4% More than 0.45 less than 1 1.7% Less than 0.45 one%

- The hardness of the granules measured according to ASTM D5230 does not exceed 50 g.

- Humidity 0.1%.

- Bulk density 1304 g / dm.

- The chemical composition and specific surface area correspond to the starting material.

Example 2a Operating modes:

- The pressing force on the rollers of the roller press is 10 kN;

- The diameter of the rollers - 0.15 m;

- Roller rotation frequency - 100 rpm;

- Wiping sieve with a cell - 1.5 mm;

- Diameter of the plate - 0.5 m;

- The frequency of rotation of the plate - 40 rpm;

- The angle of the plate - 10 degrees .;

- The height of the pile plate - 0.2 m;

- The amount of added unconsolidated powder of zinc oxide is 5% by weight of the load.

Results:

- Received granules of spherical shape with a diameter of:

More than 5 mm 0% More than 3 less than 5 mm 1.8% More than 2 less than 3 mm 22.3% More than 1 less than 2 mm 62.5% More than 0.45 less than 1 11.7% Less than 0.45 1.7%

- The hardness of the granules measured according to ASTM D5230 does not exceed 50 g.

- Humidity 0.1%.

- Bulk density of 1128 g / DM ³ .

- The chemical composition and specific surface area correspond to the starting material.

Example 2b Operating modes:

- Pressing force on rollers - 60 kN;

- The diameter of the rollers - 1.2 m;

- Roller rotation frequency - 10 rpm;

- Wiping sieve with a cell - 5 mm;

- Diameter of the plate - 3 m;

- The frequency of rotation of the plate - 10 rpm;

- The angle of the plate - 55 degrees .;

- The height of the pile plate - 1.0 m;

- The amount of added unconsolidated powder of zinc oxide is 95% by weight of the load.

Results:

- Received granules of spherical shape with a diameter of:

More than 5 less than 10 mm 48.9% More than 3 less than 5 mm 34.6% More than 2 less than 3 mm 14.1% More than 1 less than 2 mm 1.5% More than 0.45 less than 1 0.9% Less than 0.45 0%

- The hardness of the granules measured according to ASTM D5230 does not exceed 80 g.

- Humidity 0.1%.

- Bulk density 1360 g / dm ³ .

- The chemical composition and specific surface area correspond to the starting material.

Example 3a Operating modes:

- The pressing force on the rollers of the roller press is 10 kN;

- The diameter of the rollers - 0.15 m;

- Roller rotation frequency - 100 rpm;

- Wiping sieve with a cell - 1.5 mm;

- Diameter of the pelletizing pipe - 0.3 m;

- The frequency of rotation of the pipe - 40 rpm;

- The angle of the pipe - 1 deg .;

- Pipe length - 15 m;

- The amount of added unconsolidated powder of zinc oxide is 5% by weight of the load.

Results:

- Received granules of spherical shape with a diameter of:

More than 5 mm 0% More than 3 less than 5 mm 0% More than 2 less than 3 mm 8.4% More than 1 less than 2 mm 36.5% More than 0.45 less than 1 41.8% Less than 0.45 13.3%

- The hardness of the granules measured according to ASTM D5230 does not exceed 30 g.

- Humidity 0.1%.

- Bulk density 1044 g / dm ³ .

- The chemical composition and specific surface area correspond to the starting material.

Example 3b Operating modes:

- Pressing force on rollers - 60 kN;

- The diameter of the rollers - 1.2 m;

- Roller rotation frequency - 10 rpm;

- Wiping sieve with a cell - 5 mm;

- The diameter of the pipe is 3 m;

- The frequency of rotation of the pipe - 10 rpm;

- The angle of the pipe - 45 degrees .;

- Pipe length - 1 m;

- The amount of added unconsolidated powder of zinc oxide is 95% by weight of the load.

Results:

- Received granules of spherical shape with a diameter of:

More than 5 less than 10 mm 36.8 0% More than 3 less than 5 mm 46.7% More than 2 less than 3 mm 12.4% More than 1 less than 2 mm 1.7% More than 0.45 less than 1 2.4% Less than 0.45 0%

- The hardness of the granules measured according to ASTM D5230 does not exceed 75 g.

- Humidity 0.1%.

- Bulk density of 1408 g / DM ³ .

- The chemical composition and specific surface area correspond to the starting material.

Similar results are obtained using a roll press.

Thus, the proposed method using the proposed device allows to obtain spherical granules with preservation of the composition of the processed powder and hardness, measured according to ASTM D5230, not exceeding 100 grams.

Claims (17)

1. A method of granulating powders, characterized in that the powder is pre-compacted, then pressed, the resulting forms are crushed, wiped through one or more screens, and the resulting powder is doused with uncompressed powder. 2. The method according to p. 1, characterized in that the preliminary compaction is carried out by a screw. 3. The method according to p. 1, characterized in that the compaction of the compacted powder is carried out by a roller or roller press with a rotation speed of the rollers or rollers from 10 to 100 rpm, with the application of a pressing force of from 10 to 60 kN. 4. The method according to p. 1, characterized in that the grinding is carried out using a knife chopper. 5. The method according to p. 1, characterized in that they carry out the rubbing of the crushed forms through a sieve with a cell from 1.5 to 5 mm. 6. The method according to p. 1, characterized in that the pelletizing is carried out on a plate granulator with a plate rotation speed of 10 to 40 rpm, a plate diameter of 0.5 to 3 meters, a plate collar height of 0.2 to 1 meter with the axis of rotation of the plate, tilted relative to the horizon at an angle of 10 to 55 degrees. 7. The method according to p. 1, characterized in that the rolling is carried out on a tubular granulator with a pipe rotation speed of 10 to 40 rpm, a pipe diameter of 0.3 to 3 meters, a pipe length of 1 to 15 meters with an axis of rotation of the pipe tilted relative to the horizon at an angle of 1 to 45 degrees. 8. The method according to p. 1, characterized in that the unconsolidated powder for rolling is used in an amount of from 5 to 95% of the loaded mass. 9. Equipment for granulation of fine powders, characterized in that it includes successively installed feed pre-auger, one or more roller or roller presses with compression rollers or rollers, a grinder, wipers, a plate or tube granulator. 10. Equipment according to claim 9, characterized in that the axis of rotation of the plate is tilted relative to the horizon by an angle of 10 to 55 degrees. 11. Equipment according to claim 9, characterized in that the diameter of the plate is from 0.5 to 3 meters. 12. Equipment according to claim 9, characterized in that the axis of rotation of the pipe is inclined relative to the horizon by an angle of 1 to 45 degrees. 13. The equipment according to claim 9, characterized in that the pipe diameter is from 0.3 to 3 meters. 14. The equipment according to claim 9, characterized in that the pipe length is from 1 to 15 meters. 15. The equipment according to claim 9, characterized in that the cleaning sieves have cells ranging in size from 1.5 to 5 mm. 16. The equipment according to claim 9, characterized in that it further comprises sorting sieves. 17. The equipment according to claim 9, characterized in that it further comprises a transportation device.

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