JPS6349730B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for hot compression molding of high-temperature reduced iron particles into lumps, and in particular for circulating and remolding fine powder reduced iron derived during compression molding and subsequent steps. The invention relates to a device.

Conventionally, as seen in JP-A-53-12712, hot compression molding of high-temperature reduced iron particles into a lump is already known and commonly practiced.

In addition, several percent of fine powder is generated during hot compression molding and during the crushing process to separate compression molded products into lumps, so in the past, after separating this generated fine powder from the lump molded products, compression molding was performed. It is circulated through the machine and remolded. However, when the amount of circulating fine powder increases as during startup, the fine powder may fall off and the feeder drive machine may be damaged due to insufficient capacity of the fine powder transportation equipment and feeder to circulate and transport the generated fine powder to the inlet of the compression molding machine. In addition, if the temperature of the high-temperature reduced iron raw material to be processed is too low or the metallization rate is too low,
Since the deformation resistance of the reduced iron particles increases during compression molding, there is a problem in that the density of the block molded product becomes smaller than the desired value due to an increase in the amount of fine powder circulation.

The present invention was made in order to improve the above-mentioned drawbacks of the conventional technology, and it uses a compression molding machine that hot compression molds reduced iron particles into a lump with a pair of press rolls, and a compression molding machine that compresses and molds reduced iron particles during the same compression molding process and thereafter. A compression molding apparatus for reduced iron comprising: a sieve device for separating fine powder reduced iron and lump reduced iron produced in the step; and a transport device for returning the separated fine powder reduced iron to the compression molding machine. The present invention relates to a compression molding apparatus for reduced iron, characterized in that the openings of the apparatus can be blocked at a desired time.

According to the device of the present invention, after the reduced iron fine powder generated in the process after compression molding is separated from the lump molded product,
In addition to circulating the reduced iron fine powder to the compression molding machine and remolding it, the separator for separating the reduced iron fine powder from the bulk molded product retains the function of separating the fine powder and not separating the fine powder, thereby facilitating the start-up of the equipment. This method can be easily carried out, and has the advantage of avoiding inconvenient situations that occur when operating conditions such as low-temperature reduced iron treatment are unknown.

The apparatus of the present invention will be explained below with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of the apparatus of the present invention, in which 1 is a high-temperature reduced iron particle, 2 is a hopper,
3 is a chute, 4 is a screw feeder, 5 is a driving motor for the screw feeder 4, 6 is a pair of molding rolls having molding recesses 6a on the surface, 7 is a lump immediately after molding, and 8 is a lump a divider for cutting off the connections between the two, 9 a block molded product, 10 a separator consisting of a sieve plate for separating the block molded product and the generated fine powder;
11 is a cooling water tank for bulk molded products, 12 is a cooling water supply pipe, 13 is a product conveyor, 14 is a product storage area, 15 is separated reduced iron fine powder, 16 is a separator chute, 17 is a conveyor for circulation of separated fine powder, 18 19 is a hopper for atmosphere replacement, 20 is a chute, 21 is a damper for the separator 10, and 22 is a direct reduction furnace for feeding new reduced iron particle raw material (not shown).
23 is a gate valve, and 30 is a chute for bulk molded products.

In the apparatus of the present invention having such a configuration, the high temperature reduced iron particles 1 in the hopper 2 are sent to the screw feeder 4 via the chute 3. Next, the high-temperature reduced iron particles are press-fitted into a pair of forming rolls 6 by a screw feeder 4, and compression-molded into a lump by the rolls 6. During this molding, some fine powder is generated. At this time, since the molded lumps are connected as shown in 7, dividers 8 are used to facilitate handling in the next process.
The connection is severed and a single lump like 9 is formed. At this time, fine powder is also generated.
Therefore, in order to circulate and reshape the reduced iron fine powder generated during compression molding and crushing of connections between lumps, the fine powder separator 10 separates the generated fine powder from the lumps, and the chute 16 is passed through the chute 16. It is then sent to circulation transportation equipment (circulation conveyor 17, elevator 18, etc.) via the circulation conveyor 17, elevator 18, etc. The reduced iron fine powder returned to the hopper 2 by the transportation equipment is compressed and formed into a lump together with the new raw material reduced iron particles again, so that it can be used effectively and the product yield can be prevented from decreasing. On the other hand, after the bulk molded product passes through the fine powder separator, it is passed through a chute 30 to a cooling water tank 1.
After being cooled to about 100° C. by being immersed in water for a predetermined time, the products are stored in a finished product storage area 14 via a finished product conveyor 13.

During normal operation, it is operated in the manner described above.
At the start-up of the apparatus of the present invention, in order to protect the screw feeder 4, the roll gap between the forming rolls 6 is increased to prevent excessive reaction force from being applied to the screw feeder 4. A large amount of fine powder accompanying the unformed powder passes through the subsequent fine powder separator 10, and at this time, the amount of fine powder circulated to the transportation equipment for fine powder circulation inevitably increases, and the equipment of the fine powder circulation system including the hopper 2 increases. This results in insufficient capacity, causing problems such as clogging of fine powder and overflow.

Therefore, like the device of the present invention, the fine powder separator 10
By attaching a damper 21 to the machine, at startup, the damper 21 is closed as shown by the solid line in FIG. 2, and the separation function of the fine powder separator 10 is stopped. By this operation, the generated reduced iron fine powder is not sent to the fine powder circulation system equipment, but directly.
Since it enters the cooling water tank 11, the above-mentioned troubles due to insufficient capacity of the fine powder circulation system do not occur. Therefore, equipment can be started up smoothly. After startup, when the gap between the rolls 6 reaches a steady state and the generation of fine powder reaches a steady state, the damper 21 is opened as shown by the broken line in FIG. 2 to activate the separation function of the fine powder separator 10. By operating the machine, the generated fine powder is circulated and re-molded, and a decrease in yield can be prevented.

As described above, according to the apparatus of the present invention, by allowing the fine powder separator to maintain the function of performing separation operation and non-separation operation using a damper, etc., it is possible to smoothly start up the reduced iron compression molding apparatus. This is extremely advantageous in terms of industrial implementation.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing one embodiment of the apparatus of the present invention, and FIG. 2 is a diagram for explaining in detail the fine powder separation function of the apparatus of the present invention.

Claims (1)

[Claims] 1. A compression molding machine that hot compression molds reduced iron particles into a lump with a pair of press rolls, and a sieve device that separates fine powder reduced iron and lump reduced iron produced during the compression molding and subsequent steps. A reduced iron compression molding apparatus comprising a transportation device for returning separated fine powder reduced iron to the compression molding machine, characterized in that the openings of the sieving device can be blocked at a desired time. Compression molding equipment for reduced iron.