JPS6391134A - Powder granulator - Google Patents

Abstract

PURPOSE:To facilitate the spherical granulation in the succeeding stage by press-forming a powdery material with a couple of press rolls having a continuous recess in the circumferential direction, and cutting the obtained stringy material into granules. CONSTITUTION:The press rolls 3 and 3' have, for example, many semicircular grooves in the circumferential direction, and the grooves of both rolls 3 and 3' are made symmetrical to each other. Accordingly, when the semicircular grooves are used, a circle is formed at the contact site between both rolls 3 and 3'. Besides, one roll 5 between a couple of cutting rolls 5 and 5' is provided with the regularly spaced acute-angle protrusions, and the other roll 5' is a flat roll having the same outer diameter as that of the roll 5. The clearance between both rolls 5 and 5' is made slightly narrower than the maximum thickness of the product formed by the press rolls 3 and 3'. By this structure, the raw powdery material 2 supplied to a hopper 1 is press-formed by the press rolls 3 and 3' into stringy formed product 4. The formed product 4 is cut in accordance wit the pitch of the protrusions on the cutting roll 5 to form columnar pellets.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an apparatus for granulating powder, particularly for producing spherical particles.

[Prior Art] It is well known that, from the viewpoint of particle shape, the fluidity of granules is better when they are more spherical than when they have an acute-angled shape. Particularly, in the case of granular materials used as fertilizers, the particle shape is required to be spherical from the viewpoint of fertilization.

As a method for producing granules from powder, compacting is used to compression mold the powder using a pair of flat rolls to form flat granules, which are then crushed using a crusher to obtain irregularly shaped granules. Alternatively, a powder material is compression molded with a pair of rolls having a large number of concave portions (hereinafter referred to as "pocket holes") on the surface, and a large number of convex portions corresponding to the pocket holes of the rolls (hereinafter referred to as "tablets") are formed. ) and then crushed in a crusher to obtain particles with a shape corresponding to the pocket holes of the roll.

Tying etc. are commonly performed.

However, in the former compacting method, it is difficult to obtain particles with a constant shape, and only irregularly shaped particles are obtained. In addition, in the latter type of briquerating, the board that connects the tablets remains around the entire periphery of each tablet as a so-called "burr", and the compression ratio of this "burr" part is larger than that of the tablet part and is harder than the tablet. Therefore, it is difficult to completely remove these burrs, and even when molded using a roll with hemispherical pocket holes, the shape of the particles obtained as a product is difficult to become spherical. Moreover, if the compression ratio of the spherical part is increased, it has the disadvantage that it becomes impossible to crush it.

[Problems to be Solved by the Invention] The present inventors have arrived at the present invention as a result of various studies on a method for improving press rolls and crushers and obtaining granules that are truly close to spheres. This is what I did.

[Means for Solving the Problems] That is, the present invention involves compressing and molding the powder using a pair of press rolls having continuous recesses along the circumferential direction when producing a granular material from a powder. The obtained string-like material is passed between a gear-shaped roll having an acute-angled convex portion at a constant interval and a flat roll, so that the thickness in the compression direction: the cutting length is 1:0.
The present invention provides a method for producing granules by cutting them into particles having a size of 5 to 1.5.

Next, an example of a manufacturing apparatus according to the present invention will be explained with reference to the drawings.

FIG. 1 shows details of the manufacturing apparatus.

The powdered material 2 supplied to the raw material hopper 1 is compressed and molded into a string-like molded material 4 by press rolls 3 and 3'. As shown in the figure, the press roller 3.3' has semicircular grooves, for example, corresponding to a desired grain size, cut along the circumference, and a large number of these grooves are continuous in the length direction. The grooves of the press roller 3.3' are made completely symmetrically, for example, when semicircular grooves are dug in the roll,
Where both rolls touch, a circle will be formed. If the grooves on both rolls are not symmetrical, the string-like material will be crimped onto whichever has greater frictional resistance, resulting in insufficient release from the rolls. The string-like connected material compression-molded by the press rollers 3 and 3' is guided to the guide 7 and cut to the cutting roll 5.
．． 5'. The cutting roll 5 is a gear-shaped roll having convex portions with acute angle tips at regular intervals, and the cutting roll 5' is a flat roll having the same outer diameter as the cutting roll 5. By making the clearance of this cutting roll 5.5' slightly narrower than the maximum thickness of the string-like molded product compression-molded by the press roll 3.3', the string-like connected object can be formed at the pitch of the protrusions of the cutting roll 5. It is cut into lengths according to the following and becomes cylindrical pellets. The shape of this pellet does not necessarily have to be cylindrical, and may be an elliptical cylinder, a rectangular parallelepiped, etc., but in order to make spheroidized particles in the next step, the ratio of the thickness and length of the pellet should be 0.5 to 0.5. A value of 1.5 is desirable.

The pellets thus obtained can be easily made into spherical particles by grinding them using a known technique (for example, Marumerizer manufactured by Fuji Paudal Co., Ltd.).

Examples manufactured using the apparatus according to the present invention will be shown below.

Example 1 Powdered ammonium chloride under 32Me was fed into a press roller to obtain a string-like molded product. The press roll has two semicircular grooves with R = 1.9 mm along the circumferential direction.
Consists of a set of rolls, the circumferential speed of the rolls is 0.2m/s
I drove with ee. A photograph of the string-like molded product obtained at this time is shown in FIG.

The string-shaped molded product formed by the press roll was then guided by a guide and introduced into a cutting roll operating at a circumferential speed of 0.8 m/sec. The cutting roll has a pitch of 4.
A gear-shaped roll with a 9 mm diameter and an acute-angled protrusion,
It consisted of a flat roll having the same diameter as this roll, and the clearance between these two rolls was adjusted to 3.0 mm.

The obtained pellets had a diameter of 3.8 mm and a cutting length of 4 to 8 mm.
A photo of the cylindrical pellet is shown in FIG. 3.

The cylindrical pellets were introduced into a coarse grinding device (Marumerizer manufactured by Fuji Paudal Co., Ltd.), and the cylindrical pellets had a diameter of 2.0 to 3 mm. E
It became a spherical particle of l+am. The obtained spherical particles had a hardness of 2.0 kg/piece with an angle of repose of 37° as measured by a Honya type hardness meter.
Met. A photograph of this particle is shown in FIG.

[Brief explanation of the drawing]

FIG. 1 is a bird's eye view showing one example of the device of the present invention. FIG. 2 is a photograph showing a string-like molded product which is an intermediate product of granules produced by the apparatus of the present invention. FIG. 3 is a photograph showing cylindrical pellets obtained from the string-like molded product of FIG. 2. FIG. 4 is a photograph showing spherical particles obtained from the cylindrical pellets of FIG. 3. Two cows 1. Reproduction of the drawings in Figure 8 (no change in the contents). 2. Reconstruction of the drawings in Figure 5. (no changes in the contents). Engraving of the drawings in Figure 5. (No changes in the contents.) Figure 4. Procedure amendment (ship). 1988. February 23rd

Claims (5)

[Claims] (1) Granules are obtained by compression-molding a powder using a pair of press rolls that have continuous recesses along the circumferential direction and cutting the resulting string-like material. conversion device. (2) The granulating device according to claim 1, wherein the concave portions of the two rolls are made symmetrically. (3) The granulating device according to claim 1, wherein the width of the flat plate portion between the recesses of the roll is 1.0 times or less the maximum depth of the recesses. (4) The string-like molded product obtained by roll forming is cut into granules so that the thickness in the compression direction:cutting length is 1:0.5 to 1.5. Granulation equipment. (5) When cutting a string-like material, the string-like material is made into granules by passing the string-like material between a flat roll and a gear-shaped roll having an acute-angled convex portion at a rotating constant interval. The granulation device according to item 3.