JPS62228418A - Manufacture of reduced iron briquette - Google Patents

Abstract

PURPOSE:To manufacture reduced iron briquettes with high molding efficiency by press-molding sponge reduced iron at a high temp. with a molding press, pressing the resulting belt-shaped briquette to higher density with molding rolls and cutting it to a prescribed size. CONSTITUTION:Sponge reduced iron 1 discharged from a reducing furnace at >=600 deg.C is charged into a molding press from a hopper 2 through a gate valve 3 and a chute 4, an upper lid 5 and a lower lid 9 are shut and both side presses 7, 8 are moved forward to mold the reduce ion 1 by preliminary pressing. The resulting belt-shaped reduced iron briquette 15 is pressed to higher density with molding rolls 10, 11, sent to cutters 13, 14 with guide rolls 12a-12f and cut into reduced iron briquettes 16 of a prescribed size. The hot reduced iron briquettes can be manufactured at a low cost without using a binder.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is directed to the use of spongy reduced iron powder obtained by reducing powdered iron ore, for example, in a fluidized fluidized reduction furnace, as a raw material for a melting reduction furnace (a metal melting furnace such as an electric furnace may also be used). The present invention relates to a method of briquetting in order to increase charging efficiency in the furnace.

(Conventional technology) Conventional techniques for forming reduced iron include: ■ A method in which fine carbon materials or inorganic binders are mixed with high-temperature reduced iron as a binder in an unoxidized state and pressure-formed using forming rolls (
JP-A-53-12712, JP-A-58-11745, JP-A-59-170222, etc.), ■ Preventing re-oxidation by press-molding reduced iron powder in an oxidizing atmosphere, or Technology aimed at improving strong earthquakes (Japanese Unexamined Patent Publication No. 57-51
No. 211, JP-A No. 55-119116, etc.), ■Although it is not specified that a binder such as carbonaceous material is mixed, high-temperature reactive granular metal is molded with a compression molding device such as a molding roll, and then sheared. Method of making 1tlr product by machine (Unexamined Japanese Patent Publication No. 51-1
48610 etc.).

(Problems to be Solved by the Invention) In the prior art described above, the pressure forming method using forming rolls has a great advantage in terms of manufacturing continuity. A characteristic of the sintering roll method is that in order to increase the yield of lumps and the strength of the finished product, a certain molding pressure is required. This causes slippage between the raw material and the rolls. Therefore, in the forming roll method, forming is generally performed using a binder, but there are limitations in controlling the biting between the raw material and the rolls and in controlling the forming pressure.
/ It was difficult to obtain a certain level of strength when converting into steel.

The present invention was made to solve the above problems, and
Utilizing the property of the metallic iron powder in the single-component iron powder at high temperature (600℃) to adhere to each other under high temperature and pressure, it is pressure-formed and agglomerated without using a binder. I created a way to do that. ■
The present invention consists of a plurality of pressure molding machines, and the upper stage is equipped with a mold press machine, which facilitates the final pressure molding with the next stage forming rolls and press molds into a predetermined density shape. After that, it is broken into a predetermined size and agglomerated.

(Means for Solving the Problems) The present invention involves pressure-forming high-temperature sponge-like reduced iron discharged from a reduction furnace into a predetermined density and shape using a mold press machine, and then further forming it using a forming roll. This is a method for producing reduced iron briquettes, which is characterized in that the reduced iron briquettes are pressure-formed until a predetermined density strength is obtained, and then broken into a predetermined size using a breaking machine.

(Function) Unlike the method in which the powder raw material is directly pressure-molded with a forming roll, the mold press machine forms a certain shape after molding with the upper mold press machine, and when the mold press machine is deformed. A band-shaped cake is formed, and its own weight acts as a pressing force on the lower forming roll, making it possible for the band-shaped cake to be bitten by the forming roll. Therefore, even if the reduced iron powder is at a high temperature, it will not get caught between the rolls after being formed into a certain shape, making it easier to form the reduced iron into brigetts.

Generally, the pressure required for pressure forming of high temperature reduced iron is 100
~3000 kg/crl, but the strength of pressure-formed reduced iron under high temperature and high pressure is proportional to the temperature and pressure. In other words, the strength increases if the molding pressure is increased, but the final strength depends on the degree of powdering in the melting reduction furnace, transportation, and charging process, and the degree of pulverization in the melting reduction furnace, transportation, and charging process, and the breaking of the strip cake after pressure molding with a breaking machine. Determined by breakability during sizing.

On the other hand, a mold press machine is easier to control the pressing force than a forming roll, so it not only maintains the shape as a previous stage of the forming roll, but also performs pressure forming by distributing a predetermined forming pressure in balance between it and the forming roll. things are possible. Therefore, the pressurized molding pressure can be easily obtained without varying the pressure of the molding rolls (also by changing the molding pressure of the mold press machine).

(Example) The present invention will be explained based on one embodiment.

The raw iron 1 which has been reduced at a temperature of 600° C. or higher in a reduction furnace (not shown) is stored in a hopper 2. There is a gate valve 3 at the bottom of the hopper, and a chute 4 at the bottom for charging into the mold press machine. When the gate valve 3 is open and the mold press machine 5°7.8.9 is in the state shown in Fig. 2. When the reduced iron 1 is filled, the gate valve 3 is closed and the upper lid 5 of the mold press is closed and locked. In this state (see FIG. 3), the presses 7.8 on both sides compress and mold the reduced iron 1.

After molding, mold press upper cover 5 and lower cover 9 are 1! The presses 7.8 on both sides then retreat outward.
The formed strip briquette/mesh 5 is bitten by its own weight into the forming rolls io and u which are already starting and rotating as shown in FIG. The briquettes are pulled out at ~12f and broken by a breaking machine 1.3.14, resulting in a lump-like product briquette 16.

The above-mentioned side press 7.8 pressurizes and compresses the strip briquette 15 in the case of high-temperature reduced iron with the forming roll 10.1.
It is primarily determined by the set strength and yield of the product briquettes obtained by molding in step 1 and breaking in breaking machine 13 and 14, but as mentioned above, the compacting pressure for turning reduced iron powder into briquettes is generally 100 It is a value that varies depending on the particle size, metallization rate, temperature, etc. of the raw material. For example, in the case of reduced iron in this implementation, the total required molding pressure to obtain product briquettes with a predetermined strength yield is 20
At 0 kg/-, productivity and formability (yield,
Due to strength), the band-shaped burr prevents it from getting caught in the forming roll.

The pressure required to obtain this with a mold press is 20k.
By applying a preforming pressure of 179 g/- of the molding pressure of the molding roll using a mold press, it was possible to mold product briquettes with a predetermined strength yield.

In this way, in the conventional briquetting of high-temperature reduced iron using forming rolls, the main forming is done with the forming rolls without using a binder, but the forming process is performed in advance under light pressure using a mold press machine. The strip briquettes are put into a forming roll by their own weight, pressure-formed with a required pressure on the forming rolls, and broken with a breaking machine to obtain a desired finished briquette.

(Effects of the invention) After the high-temperature reduced iron discharged from the reduction furnace is preformed with pressure in a mold press to form a certain shape, it does not get caught in the forming rolls, so the reduced briquettes are smooth and have good forming efficiency. It becomes easier to

In addition, it is easy to bag high-temperature products (bricare) into the iron bath smelting reduction furnace, making it possible to save energy.

Also, since it has good moldability, it is possible to reduce the cost of the binder and the equipment cost.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; FIG. 1 is a schematic explanatory diagram of the present invention, FIGS. 2 to 5 are explanatory diagrams showing the steps of the present invention, and FIG. 6 is the same as that of FIG. -1' line arrow enlarged view. ■ is 1 element iron, 2 is hopper, 3 is gate valve, 4 is chute, 5 is mold press top cover, 7.8 is mold press machine, 9 is mold press top cover, 10 and 11 are forming rolls, 12a~ 12r is a guide roll, 13 and 14 are breaking machines, 15 is a strip briquette, and 16 is a product briquette. Patent Applicant: Nippon Steel Corporation (No change in content) Figure 1 Figure 2 Negative 5 3 Figure 4 Figure 5 Figure 6 Procedural Amendment ζ Entry) June 1986 On the 16th, Mr. Michibu Uga, Commissioner of the Government Office] ° IB'i display 1! 'l (il 61 'l-patent aM7089
No. 5 No. 2 Name of the invention Method for producing reduced iron briquettes 3, 111 + person who makes the correction Relationship with e1 Patent originator (6 valleys unchanged)

Claims (1)

[Claims] The high-temperature sponge-like reduced iron discharged from the reduction furnace is pressure-formed to a predetermined density and shape using a mold press, and then further pressure-formed using forming rolls until a predetermined density and strength is obtained, and then to a predetermined size. A method for producing reduced iron briquettes, which is characterized in that the reduced iron briquettes are broken.