JP7458921B2 - Rotary stirring type heat treatment equipment - Google Patents

Description

The present invention relates to a rotary agitation type heat treatment device that applies agitation heat treatment to a workpiece and a heat treatment method using the device.

Rotary stirring type heat treatment apparatuses are used to perform various heat treatments on objects to be treated. This rotary stirring type heat treatment apparatus introduces a workpiece into a rotating cylindrical furnace, and performs heat treatment while moving the workpiece from upstream to downstream of the furnace through rotation.
On the other hand, the purpose of this heat treatment varies depending on the type of object to be treated, and examples of the purpose include calcination for lime, mixing for electrode materials, and oxidation for metal powder.

In this rotary stirring type heat treatment apparatus, various proposals have been made to perform heat treatment more effectively.

For example, Patent Document 1 describes a rotary stirring type heat treatment device having a beater member that rolls on the inner surface of a rotating furnace tube to impart an impact to the workpiece, and the rolling beater member is said to impart an impact to the workpiece, preventing the workpiece from adhering to the inner surface of the furnace tube.

For example, Patent Document 2 describes a rotary stirring type heat treatment device that has a rotor with three or four blades inside a rotating furnace tube, where L is the length of the rotor blades and R is the inner diameter of the furnace tube, and where L/R is 0.1 to 0.6, and is said to be capable of oxidizing electrolytic copper powder to cupric oxide powder.

JP2012-163282A Patent No. 6056709

The rotary stirring type heat treatment apparatus described in Patent Document 1 heat-treats a workpiece of 5 mm or less whose main component is lime, and the rotary stirring type heat treatment apparatus described in Patent Document 2 heat-treats electrolytic copper powder. If the object to be treated is a powder or a small object close to a powder, heat treatment as described in Patent Documents 1 and 2 is possible. However, these Patent Documents 1 and 2 do not describe the heat treatment of a lumpy object, and according to the study of the present inventor, although these rotary stirring type heat treatment apparatuses have a beater member or a rotor, When actually heat-treating a block of material, it was found that sufficient heat treatment was difficult.

In particular, an object of the present invention is to provide a rotary agitation type heat treatment apparatus that can reliably heat treat a block to be treated, and a heat treatment method using the apparatus.

The present inventors have conducted extensive research into the structure of a rotary stirring type heat treatment apparatus capable of heat treating even lump-shaped objects, such as lump scrap containing tungsten (W), for which there has been a demand in recent years for cheap and reliable recycling, that do not pass through a sieve with a mesh size of 5 mm, but pass through a sieve with a mesh size of 30 mm.
Here, sieves with openings of 5 mm and 30 mm refer to sieves having square openings with sides measuring 5 mm and 30 mm, respectively.

As a result, we have gained the novel insight that reliable heat treatment is possible if multiple treatment zones are provided along the longitudinal direction of the cylinder (furnace tube) on the inner circumference of the cylinder, and these treatment zones rotate as the cylinder rotates, and the chunks of material supplied to each treatment zone are prevented from migrating (moving) to other treatment zones, and are heat-treated while being stirred and sized.

The present invention is based on this knowledge and is as follows.
"(1)
A rotary stirring type heat treatment device for heat treating a workpiece,
a heat treatment section having a cylindrical body into which the object to be treated is supplied from one end, heat-treated therein, and discharged from the other end;
heating means for heating the inside of the cylindrical body;
A processing zone forming means is provided on the inner periphery of the cylindrical body and is divided in the inner periphery direction of the cylindrical body and forms a plurality of processing zones along the longitudinal direction of the cylindrical body,
The processing zone forming means rotates by intermittent rotation of the cylindrical body, and has a shape that prevents the object to be processed supplied to each processing zone from moving to other processing zones. thing,
A rotary stirring type heat treatment equipment featuring:
(2) A method for heat treatment of a workpiece, characterized by using the rotary stirring type heat treatment apparatus described in (1) above. ”

The rotary agitation type heat treatment apparatus of the present invention is particularly capable of heat-treating even block-like objects, and the heat treatment method of the present invention can reliably heat-treat the same block-like objects. It's a method.

FIG. 1 is a schematic cross-sectional view showing an example of a rotary stirring type heat treatment apparatus of the present invention. FIG. 3 is a schematic radial cross-sectional view of a cylindrical body of an example of a processing zone forming means.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention for heat-treating a block-shaped object will be described with reference to the drawings, but the present invention is not limited to the following embodiments.

In addition, the lumpy processed material as used in this specification refers to the lumpy processed material that does not pass through a sieve with an opening of 5 mm but passes through a sieve with a 30 mm opening (a lumpy processed material that does not pass through a sieve with an opening of 30 mm). (If the material is crushed, it may unintentionally contain particles that are too large to pass through the 5 mm sieve.) Examples include oxidation treatment in the air (in an oxidizing atmosphere) in which metals such as chromium and copper are treated in bulk, and firing treatment in which industrial waste such as scrap is treated.

A rotary stirring type heat treatment 1 which is an embodiment of the present invention shown in FIG. 1 has a supply section 2, a heat treatment section 3, and a discharge section 4 from upstream to downstream. In FIG. 1, illustration of the processing zone forming means provided in the heat processing section 3 is omitted.

The supply unit 2 includes, for example, a hopper 21 and a screw conveyor 22 (detailed configuration is not shown). In the hopper 21, a lumpy workpiece to be heat-treated, for example, a lumpy scrap containing tungsten, is stored, and a predetermined amount of the stored lumpy workpiece is supplied to the heat treatment section 3 by a screw conveyor 22. Ru.

The discharge section 4 has a discharge means 41 for discharging the block-like processed material subjected to the heat treatment in the heat treatment section 3 to the outside of the rotary stirring type heat treatment apparatus 1 . There are no particular restrictions on the structure of this discharge means 41 as long as it can discharge the heat-treated lump-like object, and any known means may be adopted as appropriate.

The heat treatment section 3 has a cylindrical body (furnace tube) 31 that is intermittently rotated by means not shown. With respect to a pedestal (not shown), this cylindrical body 31 is inclined so that one end side (the side having the supply section 2, upstream) is higher than the other end side (the side having the discharge section 4, downstream). ing. That is, the height of the cylindrical body 31 is lower on the discharge section 4 side than on the supply section 2 side. A processing zone forming means 5 is provided on the inner periphery of the cylindrical body 31, and as described later, the processing zone forming means 5 is intermittently rotated by the intermittent rotation of the cylindrical body 31, and the blocky coating supplied from the supply section 2 is The processed material is heat-treated while being stirred and sized, and then moves toward the discharge section 4. When the lumpy material to be treated reaches the end of the cylindrical body 31 on the side of the discharge section 4, it falls into the discharge section 4 and is discharged from the rotary stirring type heat treatment apparatus 1 by the discharge means 41. There is.

Further, although not shown in the drawings, the heat treatment section 3 is provided with a heater constituted by, for example, a resistance heating element as a heating means for heating the block-shaped object, and the heater is made to generate heat. The inside of the cylindrical body 31 is heated to a predetermined temperature. Note that a predetermined gap is provided between the cylindrical body 31 and the heater so that the cylindrical body 31 can rotate intermittently.

Processing zone forming means 5 that is divided in the inner circumferential direction of the cylindrical body 31 and forms a plurality of processing zones 6 along the longitudinal direction of the cylindrical body 31 is provided on the inner periphery of the cylindrical body 31 . Each of the processing zone forming means 5 has, for example, a hook shape in the radial cross section of the cylindrical body 31 as shown in FIG. The same cross-section of the cylindrical body 31 has the same hook shape (those of the same shape are successively provided from upstream to downstream of the cylindrical body 31), and forms a processing zone 6, in which the supplied lumps are Holds the object to be processed.

Then, when the intermittent rotation of the cylinder 31 is stopped, the lump-shaped material supplied to each of the multiple processing zones 6 is discharged onto the inner circumference of the cylinder 31 in front of each processing zone 6 (in the direction of rotation), where it is stirred. When the rotation of the cylinder 31 is resumed, the discharged lump-shaped material is returned to each original processing zone 6. In other words, the lump-shaped material in each processing zone 6 essentially returns to the same processing zone 6 again, so that the movement of the lump-shaped material in each processing zone 6 to other processing zones 6 is suppressed. It is presumed that by repeating this series of movements of the lump-shaped material, the oxidized lump-shaped material covers the non-oxidized lump-shaped material, leaving no unoxidized portions, and uniform heat treatment is possible.

Here, suppressing the movement of the lumpy processed material does not mean that the lumped processed material does not move at all, but the lumped processed material in each processing zone 6 is limited to a maximum of about 10% by volume. , which means to allow movement.

The object of the present invention can be achieved by providing one treatment zone forming means 5 on the inner periphery of the cylindrical body 31, but it is possible to achieve the object of the present invention by providing one treatment zone forming means 5 on the inner periphery of the cylindrical body 31. is preferred. Further, it is preferable that the same amount of the lump-like material to be processed is supplied to each processing zone 6 .

In addition, the distance between the hook-shaped tip of each processing zone forming means 5 and the inner periphery of the cylindrical body 31 (length M in FIG. 2) is, for example, the inner diameter of the cylindrical body D In this case, it is preferable that M/D is 0.01 to 0.06 (1 to 6%). The reason is that when within this range, the intermittent rotation of the processing zone 6 caused by the rotation of the cylindrical body 31 performs the heat treatment while stirring and grading the lumpy material, and the material is supplied to each processing zone 6. This is because it may be possible to more reliably suppress the movement of the lump-like processed material to other processing zones 6. The value of M/D is more preferably 0.02 to 0.04 (2 to 4%).

Although the shape of the processing zone forming means 5 is shown as a hook shape as shown in FIG. 2, it is not limited thereto. That is, its shape is such that when the intermittent rotation of the cylindrical body 31 stops, a lumpy workpiece is released onto the inner periphery of the cylindrical body 31 in front of it, and when the rotation resumes, the released lumpy workpiece returns to the original process. Anything that allows you to return to zone 6 is fine.

An example of the rotary stirring type heat treatment apparatus of the present invention will be described in detail below, but the present invention is not limited to the example at all.

A scrap containing tungsten (WC-Co scrap (the mass ratio of WC and Co is 9:1)) was used as the bulk material to be processed. This scrap was crushed. Then, this scrap was subjected to heat treatment using a rotary stirring type heat treatment apparatus 1 having a hook-shaped treatment zone forming means 5 shown in FIG. 2, and the results (Examples 1 to 3) are shown in Table 1.

On the other hand, for comparison, although the same scrap as in the example was used as a lumpy workpiece and a Radi blade was used as the processing zone forming means 5, the workpiece in the processing zone was different from other processing zones. The heat treatment was performed using a rotary stirring device (corresponding to the one described in Patent Document 2) that does not suppress the transition to . The results (Comparative Examples 1 and 2) are shown in Table 2.

In Tables 1 and 2, the supply amount, treatment temperature, and treatment time are the same, and only the presence or absence of suppression of migration of the lumpy material to be treated differs. Here, the supply amount is the amount of scrap supplied, the processing temperature is the maximum temperature and minimum temperature of the cylindrical body of the rotary stirring type heat treatment apparatus, and the processing time is the residence time of the scrap in the cylindrical body. In addition, the gap is the value of M/D when the distance between the tip of the blade of the hook-shaped processing zone forming means or the Radii blade and the inner circumference of the cylinder is M, and the inner diameter of the cylinder is D. Yes, when the processed material is a lump, if this value is in the range of 0.01 to 0.06 (1 to 6%), the migration of the processed material to other processing zones will be further suppressed. This was confirmed.

In addition, the mass increase rate is
[(mass after heat treatment)/{(mass before heat treatment) x 1.19}] x 100
It is defined as , and corresponds to the oxidation rate.
In addition, 1.19 is the mass before and after oxidation when WC-Co scrap (mass ratio of WC and Co is 9:1) is completely oxidized and WO ₃ , CoWO ₄ and CO ₂ are generated. It is a ratio.

As is clear from Tables 1 and 2, Examples 1 to 3 all exhibited a high mass increase rate because the material to be processed in the processing zone was inhibited from migrating to other processing zones. , oxidation treatment was performed efficiently. On the other hand, in Comparative Examples 1 and 2, the mass increase rate was low because the migration of the processed material to other processing zones was not suppressed, and it was confirmed that the oxidation treatment was not sufficiently performed. Ta.

The present invention can efficiently perform heat treatment even on bulk objects to be treated, and can satisfactorily achieve energy saving and cost reduction in heat treatment.

1 Rotary stirring type heat treatment device 2 Supply section 21 Hopper 22 Screw conveyor 3 Heat treatment section 31 Cylindrical body (furnace core tube)
4 Discharge section 41 Discharge means 5 Processing zone forming means 6 Processing zone D Inner diameter M of the cylindrical body Distance between the tip of the processing zone forming means (hook shape) and the inner periphery of the cylindrical body

Claims (2)

A rotary stirring type heat treatment device for heat treating a workpiece,
a heat treatment section having a cylindrical body into which the object to be treated is supplied from one end, heat-treated therein, and discharged from the other end;
heating means for heating the inside of the cylindrical body;
A processing zone forming means is provided on the inner periphery of the cylindrical body and is divided in the inner periphery direction of the cylindrical body and forms a plurality of processing zones along the longitudinal direction of the cylindrical body,
The processing zone forming means is rotated by intermittent rotation of the cylindrical body, and has a shape that prevents the object to be processed supplied to each processing zone from moving to other processing zones. thing,
A rotary stirring type heat treatment equipment featuring: A method for heat treating an object to be treated, comprising using the rotary stirring type heat treatment device described in claim 1.

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