JPS6235443B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for producing highly active metal particles such as magnesium.

Conventionally, there are many methods for producing metal granules from molten metal, which involve combinations of methods for dispersing molten metal and cooling methods.

Recently, there has been active research into increasing the cooling rate, especially when miniaturizing and solidifying products.In this case, a method is proposed in which molten metal is injected onto the surface of water moving at high speed from a fixed nozzle with an opening as small as possible. is being carried out.

When using this method, fine products can be obtained, but on the other hand, it has the following drawbacks.

(1) It is necessary to apply pressure to the molten metal and feed it into the nozzle.

(2) Because the nozzle diameter is small, it is easy to get clogged.
Productivity is low.

(3) Selection conditions such as the speed and angle at which molten metal is sprayed onto the water surface and the moving speed of the water surface are delicate.

(4) Since the molten metal is once injected into the air, it takes a long time to cool down, and highly active metals may oxidize or even burn.

As mentioned above, there are still points that require further research.

In the present invention, instead of spraying the molten metal under pressure from a fixed nozzle as described above, by attaching the nozzle to a rotating cup, the molten metal is spouted by centrifugal force and the tip of the nozzle is placed in a moving water layer. enables forced dispersion and rapid cooling of molten metal with high efficiency,
Another object of the present invention is to provide a method and apparatus for manufacturing metal granules that can be carried out continuously.

Hereinafter, the present invention will be explained in detail based on embodiments shown in the drawings.

1 and 2 illustrate one embodiment of the present invention.

In FIG. 1, 1 is an inner cup, 4 is an outer cylinder of the inner cup 1, and 18 is an outer cup. The inner surface of the outer cylinder 4 of the inner cup 1 is lined with a material such as ceramic (indicated by reference numeral 2).

A long nozzle 3 made of ceramic or the like is provided on the inner cup 1 to protrude in the lateral direction, and its tip protrudes through the outer tube 4 to form the outer cup 1.
It extends to the vicinity of the inner wall of No. 8.

The bottom of the inner cup 1 is fitted into a recess in the base 1a, and a hollow cylindrical shaft 5 is provided at the bottom of the base 1a.
has been erected.

The base 1a has an inner and outer cup 18 of the cylindrical shaft 5.
A passage 6 is provided for communicating with the inside of the cup 18, and a water fountain 6a communicates with the inside of the outer cup 18.

The cylindrical shaft 5 is rotatably supported by thrust bearings 9, 10, and 11, and a rotary joint 7 is attached to the lower part thereof.

A water conduit 7a equipped with a flow meter 8 is connected to the rotary joint 7.

A pulley 21 is fixed near the lower end of the rotating shaft 5. A V-belt is stretched endlessly between the pulley 21 and a small pulley 23 attached to an electric motor 22 installed on an adjacent frame 22a.

12 is a cylindrical body for protecting and supporting the cylindrical shaft 5. Bearings 9 and 10 are installed above and below this cylindrical body 12 and support the cylindrical shaft 5. 12' is an outer cover of the cylindrical body 12.

A pulley 27 is also attached to the lower end of the cylindrical body 12. A V-belt 28 is stretched endlessly between this pulley 27 and a small pulley 26 attached to an electric motor 25 installed on an adjacent frame 25a.

At the upper part of the cylindrical body 12, there is a wave prevention plate 16 at the inner lower part.
An outer cup 18 having a water fountain 17 at its upper end is installed concentrically with the inner cup 1. 18' is a short tube connecting the outer cup 18 and the cylindrical body 12.

Molten metal 20 (hereinafter referred to as
A supply tank 19 (simply referred to as "molten metal 20") is attached. The lower end of the supply tank 19 opens into the inner cup 1 and supplies the molten metal 20 into the inner cup 1.

A casing 29 is provided on the outside of the outer cup 18 and encloses the outer cup 18 and the short tube 18'.
is provided.

A discharge port 30 is formed in the lower part of the casing 29. Below the discharge port 30, a product receiving box 31 having a number of small holes 31a in the bottom is located. A water tank 32 is provided.

33 is a frame for holding the cylindrical shaft 5 and the cylindrical body 12, 13 is a holding base for rotatably holding the cylindrical body 12, and 34 is a main gantry.

The cylindrical body 12 is a bearing 14 provided on a holding base 13.
and 15 are rotatably supported.

The holding base 13 has a plurality of rods 35 with bolts.
and 36, it is firmly constructed on the casing 29 and the main pedestal 34.

Next, a method for manufacturing metal particles using the apparatus of the present invention configured as described above will be explained.

First, the electric motor 22 is started to rotate the inner cup 1 via the cylindrical shaft 5. At the same time, electric motor 25
to rotate the outer cup 18 through the cylinder 12. The respective rotational speeds are determined depending on the required magnitude of the centrifugal force to be applied to the molten metal and the relative speed between the tip of the nozzle 3 and the cooling water described below. Regarding the direction of rotation, when it is desired to increase both the centrifugal force and the relative speed, the inner cup 1 and the outer cup 18 may be rotated in opposite directions, and when it is desired to increase the centrifugal force and decrease the relative speed, they may be rotated in the same direction.

When the rotation becomes steady, water is pumped out from the water tank (not shown) by a pump (not shown), passed through the flow meter 8 through the water conduit 7a, and then into the cylinder via the rotary joint 7. Feed it into the shaft 5.

This water passes through the cylindrical shaft 5, enters the passage 6 of the base 1a of the inner cup 1, and is ejected from the spout 6a toward the wall surface of the outer cup 18.

The water that has entered the outer cup 18 is
Therefore, if the G value (ratio of centrifugal acceleration and gravitational acceleration) at that time is increased, the free surface of the water becomes a cylindrical surface as shown in Figure 1 (hereinafter, this cylinder of water is called "water cylinder"). layer W") is formed.

The height of the liquid level, that is, the size of the diameter of the cylindrical surface, is determined by the water supply flow rate, the G value for the water layer W, and the shape and dimensions of the water fountain 17, so by adjusting the water supply flow rate, It can be controlled and the outer cup 18 can be fitted with an overflow hole to force it to remain constant.

The tip of the nozzle 3 attached to the inner cup 1 is made to enter the water layer W from the cylindrical surface of the water.

Next, the molten metal 20 is poured from the molten metal supply tank 19 installed above the upper opening of the inner cup 1. The injected molten metal 20, like the water in the outer cup 18, forms a cylindrical free molten metal surface (hereinafter, the cylindrical body of the molten metal 20 is denoted by M) due to centrifugal force. Then, the molten metal 20 has a depth equal to the distance between the cylindrical free molten metal surface and the tip of the nozzle 3, and a centrifugal force corresponding to the G value is generated. Squirt inside.

The molten metal spouted from the opening of the nozzle 3
The moment it comes out, it is forcibly sheared and dispersed by the water passing through it, and is rapidly cooled and solidified by the water.

The dispersed and solidified granules (products) are ejected into the casing 29 together with water from the water fountain 17 provided in the outer cup 18 by centrifugal force, and are discharged through the discharge port 30.
After that, the product is taken out to the product receiving box 31.

The granules and water that entered the product receiving box 31 are discharged into the water tank 32 through the small hole 31a at the bottom.
Separation of water and particulate matter (product) takes place. For this separation, a centrifugation method or the like may be applied as necessary.

Note that if the temperature of the molten metal cannot be much higher than the melting point of the metal, the molten metal that is first injected will solidify at the tip of the spout 17, where the temperature has dropped as it comes into contact with water, before ejecting, and the molten metal will solidify before spouting. 17 may become clogged. In this case, first, the outer cup 18
Injecting the molten metal 20 is started by making the depth of the liquid shallow so that the cylindrical surface of the water inside does not reach the tip of the spout 17, and after the molten metal starts to spout steadily from the spout 17, the water supply amount is increased. to raise the liquid level so that the tip of the water fountain 17 enters the water layer W.

Next, examples clarifying the conditions for implementing the present invention,
The specific effects based on this will be shown in experimental examples.

[Experiment example]

The specific implementation conditions of the present invention are as shown below.

(1) Diameter of one inner cup 100mm (2) Rotation diameter of nozzle 3 tip 260mm (3) Diameter of nozzle 3 tip 2.0mm (this can be from 2.0 to 5.0mm) (4) Rotation of inner cup 1 number and peripheral speed
100rpm, 13.6m/sec (This is 1000~3000rpm, 13.6~40.8m/s
(5) Rotation speed and circumferential speed of outer cup 18
500 rpm, 6.8 m/sec As the metal used in the experiment, 700 g of aluminum for dissolving and deoxidizing was melted in a graphite crucible, and this molten metal was poured into the inner cup 1 at 780°C.

As a result, as shown in FIGS. 3 and 4, granules 37 are nearly spherical and have a diameter of about 50 to 100 μm.
was gotten. In addition, in FIGS. 3 and 4, what is shown around the particulate matter 37 is the embedded resin 38.
It is.

In this case, since the granules 37 are relatively small and extremely difficult to cut or polish, a desired plurality of granules 37 may be arbitrarily taken out of the large number of granules 37 obtained by the present invention. , it was embedded in a embedding resin 38 made of phenolic resin, it was cut as appropriate, and its surface was polished to obtain what is shown in FIGS. 3 and 4.

As can be seen from FIG. 4, the granules 37 obtained by the present invention are polycrystalline, and the size of the crystals 37a is extremely small, 1 to 5 μm. Note that the crystal size of polycrystals obtained by mold casting such as die casting is usually 25 to 60 μm, for example.

The fact that the crystals 37a of the granules 37 obtained in the present invention are extremely small indicates that the tensile strength and elongation are correspondingly large, as can be seen from Hall-Petsch's law.

Further, in the present invention, since the granular material 37 is rapidly cooled in the water layer W, a supersaturated solid solution is formed in the way the elements are mixed. Therefore, the sintering conditions for sintering the particulate matter 37 can be easily set. Furthermore, high strength can be expected through heat treatment.

As is clear from the above description, since the embodiment of the present invention is constructed and operated as described above, it is possible to achieve the following effects.

(1) The molten metal is dispersed by forced dispersion by the shearing action of water at the nozzle opening, so it is powerful and reliable, and has a large processing capacity.

(2) For the same reason as in the previous section, the size of the nozzle opening has almost no relation to the particle size of the product. Therefore, even when making fine particulate products, the nozzle opening can be large, making it easy to manufacture and eliminating the risk of clogging.

(3) Since the molten metal is directly jetted into the water and instantly dispersed, a large cooling rate can be achieved.

(4) Since the rotational speed and direction of rotation of the inner and outer cups can be freely selected, the granulation conditions can be changed significantly and continuously.

(5) Since the molten metal ejected from the nozzle does not pass through the air, it is not oxidized by the air, and the cooling rate is also reduced accordingly.

(6) Continuous operation is possible.

(7) The tip of the nozzle is only slightly submerged in the water, and when it rotates, water resistance only acts on the tip of the nozzle, so the power required is relatively small.

(8) Polycrystalline granules consisting of fairly small crystals can be obtained extremely easily and reliably, and granules with good mechanical properties such as tensile strength and elongation can be obtained.

(9) Since relatively small granules can be obtained, they can be used as they are for sintering.

(10) Since granules can be rapidly cooled in the water layer,
The way the elements are mixed creates a supersaturated solid solution, the sintering conditions for sintering granules can be easily set, and high strength can be expected through heat treatment.

[Brief explanation of the drawing]

The figures illustrate one embodiment for carrying out the invention. FIG. 1 is a longitudinal sectional front view, and FIG. 2 is a sectional view taken along the line AA in FIG. 1. Further, FIG. 3 is a cross-sectional view showing an example of granular material obtained by the present invention,
FIG. 4 is a partially enlarged sectional view of FIG. 3, and FIGS. 3 and 4 show the structure corresponding to a micrograph. 1 is the inner cup, 1a is the base of the inner cup, 2
is lined with material such as ceramics, 3 is the nozzle, 4 is the outer cylinder of the inner cup, 5 is the cylindrical shaft, 6 is the passage in the base of the inner cup, 6a is the water fountain, 7 is the rotary joint, and 7a is the guide. Water pipe, 8 is flow meter,
9, 10, 11 are thrust bearings, 12 is a cylindrical body,
12' is the outer cover of the cylindrical body, 13 is the holding stand, 14,1
5 is a bearing, 16 is a breakwater material, 17 is a water fountain, 18 is an outer cup, 18' is a short tube, 19 is a supply tank for molten metal, 20 is a molten metal, 21 and 27 are pulleys, 2
2, 25 are electric motors, 22a, 25a are frames, 2
3 and 26 are small wheels, 24 and 28 are V belts, 29
is the casing, 30 is the discharge port of the casing, 31
3 is a product receiving box, 32 is a water tank, 33 is a pedestal, 34 is a main pedestal, 35 and 36 are rods with bolts, 37 is a granular material, 38 is an embedded resin, W is a water tank formed in the outer cup 18, M is a cylinder of molten metal formed within the inner cup 1.

Claims (1)

[Scope of Claims] 1. The inner and outer cups are rotated separately in the same or opposite directions, and the outer circumference of the cup is transferred from the inner cup to the water layer formed on the inner surface of the circumferential wall of the outer cup. 1. A method for producing metal granules, which comprises spouting and dispersing molten metal through a nozzle attached to the water layer and having a tip inserted into the water layer. 2. An inner cup that has a nozzle that protrudes to the vicinity of the inner wall surface of the outer cup and is rotatably supported on an axis;
An outer cup that is rotatably supported on a shaft separately from the inner cup is arranged concentrically, and a hollow cylindrical shaft that communicates with a water source is connected to the lower end of the inner cup. 1. An apparatus for producing metal granules, comprising: a supply pipe facing a wall surface and communicating with a passage for supplying water, and supplying molten metal into an inner cup.