JPS62228434A - Method for briquetting reduced iron or prereduced ore - Google Patents

Abstract

PURPOSE:To efficiently briquette a powdery substance such as reduced iron to the desired size by feeding starting materials to be briquetted to a pair of flat rolls, press-molding it under excess pressure and continuously cutting the resulting molded body. CONSTITUTION:Hot powdery or granular reduced iron or prereduced ore is fed to the mixing part M of a molding apparatus 2 through a container 1 and a storage bottle 3. Pulverized coal is also fed to the mixing part M through a hopper 11, a constant feeder 12, a screw conveyor 13 and a chute 14. They are mixed in the mixing part M and fed to smooth molding rolls 5 under excess pressure applied by a screw feeder 4. A plate-shaped molded body formed by rolling with the rolls 5 is cut to a prescribed size with a pair of edged cutting rolls 6. The resulting briquettes drop into a cooling tank 8.

Description

Detailed Description of the Invention (Industrial Application Field) Forming rolls and cutting machines using flat rolling rolls when powdered or sponge-like reduced iron or powdered pre-reduced ore is mixed with carbonaceous material and agglomerated. The present invention relates to a method for agglomerating reduced iron or pre-reduced ore using a combination of the following.

(Prior art) Powdered or sponge-like reduced iron is generally charged into an electric furnace (reduction melting furnace) and melted, or has a high re-oxidation property, or is difficult to charge into a reduction melting furnace. From there, it is made into briquettes using pressure rolls.

Also, in the smelting reduction method, the reduction rate of pre-reduced ore may not be as high as reduced iron, but the same problems as reduced iron occur, so briquettes are often used.In this case, reduced iron, pre-reduced ore In either case, carbonaceous material may be added for reduction and melting in the reduction and melting furnace in the subsequent process.

As a molding device for forming the above-mentioned briquettes, a briquette machine is already in practical use as a known technology not only for reduced iron but also for other fields. When using this briquetting machine to form materials that are difficult to agglomerate, such as sponge-like reduced iron, powdered pre-reduced ore, or powdered coal, a pushing device is used to add a small amount of binder and forcefully push the material. Pressure molding is generally performed using a pressure molding roll provided.

In this pressure molding roll, a recess is formed between the opposing rolls, and after compression molding, the briquettes formed by this recess are broken and separated by a separator. The molding and breaking separation mechanism has the following drawbacks.

Firstly, the pregetting machine forms recesses in the pressure roll for molding and uses these to form, so the shape of the recesses is severely worn, reducing compressibility under pressure and causing a sudden drop in lump yield. Therefore, the pressure forming rolls need to be replaced more frequently.

Secondly, this pressure forming roll has a special structure with recesses, making it difficult and expensive to manufacture.

Thirdly, productivity is low because the original purpose is to obtain individual molded products with such a special structure.

The fourth is a mechanism that, while aiming to obtain the above-mentioned individual molded products, continuously performs forced indentation and compresses with pressure molding rolls, supplying raw materials suitable for each molded product in batches. Because it does not have a mechanism to separate each molded product after pressure molding, it is difficult to separate each molded product independently, and some parts are connected to form a chain, so a separator must be installed immediately after the molding roll to separate them individually. Normally, this is not the case. (Reference Art No. 53-12712) (Problems to be Solved by the Invention) The present inventors provide a new high-productivity agglomeration method that improves these drawbacks. In other words, it is an important element for agglomeration.■ The material is pressurized and compressed to obtain a high-density molded body.■
The present invention provides an agglomeration method having a function of cutting this high-temperature, high-density object into a size and shape according to the purpose of use.

(Means for Solving the Problems) The present invention is an agglomeration method having the above two important functions, and its feature is that the pressure forming roll is a normal flat roll having no special large structure. The granular or powdered reduced iron or pre-reduced ore is supplied to a flat roll (pressure molding roll) for pressure molding, and immediately after this, it is synchronized with the rotation speed of this molding roll. This is where a cutter is installed to cut the material to the specified size.

(Function) In the present invention, when feeding materials such as granular or powdered reduced iron or pre-reduced ore to the forming roll, a certain amount of extra pressure (force to prevent anti-tθ of the granular raw material) is applied to the material. Since the material is prevented from being bitten from the forming roll, the material is sufficiently bitten by the forming roll and can be formed.

In addition, it is possible to continuously cut the plate-shaped molded product formed by this molding roll into a predetermined shape using a cutting machine synchronized with the rotation speed of the molding roll, which greatly increases production volume. It is also very economical in terms of equipment and easy to manufacture.

In addition, since the cutting machine only needs to have a cutting function, it is possible to select equipment suitable for the amount of cutting, and by controlling the cutting speed, it is possible to freely change the size and shape of the molded product.

Figure 4 shows the agglomeration yield when pre-reduced ore is agglomerated according to the present invention.
In the case of 0%, the agglomeration yield is about 80% at a temperature of 700° C., and the throughput is about twice that of the conventional method.

As described above, the present invention has been described as a method for agglomerating powdery substances such as pre-reduced powdered ore at high temperatures, but the present invention is not limited to application only to forming such pre-reduced powdered ore, but also metals such as reduced iron. It can also be applied to items with a high conversion rate, sintered ore, and items that require mass production. In that case, it goes without saying that the forming roll and cutting machine that best suits the material can be selected.

(Example) The present invention will be described based on examples of the present invention implementation apparatus shown in FIGS. 1 to 3.

Powdered 800℃ discharged from pre-reduction furnace (not shown)
The above preliminary reduced ore is sent to the molding device 2 via the container 1 storage bottle 3 and supplied to the mixing section M.

On the other hand, powdered coal is supplied to the mixing section M via the hopper 11, constant feeder 12, screw conhair 13, and chute 14 of the coal supply device 10, where it is mixed with the pre-reduced ore and subjected to excess pressure by the screw feeder 4. Kake,
The material is fed under pressure to a forming roll 5 made of a smooth roll. The plate-shaped molded product rolled by the forming roll 5 is synchronized with the forming roll 5. For example, as shown in FIGS. 2 and 3, the vertical blade CH (CH
') and a pair of bladed cutting rolls 6 having a horizontal blade C (C')
．． 6' (opposed vertical blades C8 and CH'' and horizontal blades C (!:C''
(are in different positions so that shearing force is applied to them), cut into a predetermined size, dropped into a cooling tank 8, cooled, passed through a vibrating converter 7, and transferred to a predetermined location at 79. Carry it out. After agglomeration, the agglomerate may be supplied hot to the next process such as a melting furnace without cooling.

In the figure, 15 is a sealing cover for preventing reoxidation by blocking the atmosphere.

Note that the cutting machine is not limited to a shearing type, but a shearing type is preferable when a material with small hardness is used as a pair of racks as in the embodiment.

(Effects of the Invention) The present invention is capable of agglomerating powdery substances, such as high-temperature pre-reduced powder ore, using a flat roll with a simple structure, which reduces the cost of forming rolls and reduces the frequency of replacement. It requires less and has good workability.

In addition, the molded product can be agglomerated into the desired shape and size using a cutting machine, and because the conventional bead-like connections are not formed, the agglomeration yield is also good, and processing capacity can be significantly improved. It is particularly effective as a method for agglomerating reduced iron or pre-reduced ore.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a schematic explanatory diagram showing an example of a device for carrying out the present invention, FIG. 2 is an enlarged explanatory diagram of the cutting machine in FIG. 1, and FIG. is Fig. 2 1-
FIG. 4 is an explanatory diagram showing the relationship between the agglomeration yield and temperature of the molded product according to the present invention. 1 is a container, 2 is a molding device, 3 is a storage bottle, 4 is a screw feeder, 5 is a molding roll, 6゜6゛ is a cutter 1! I
TWJ, 7 is a vibration conveyor, 8 is a cooling tank, 9 is a discharge conveyor, 10 is a carbon material supply device, 11 is a hopper, 12 is a constant feeder, 13 is a screw conveyor, 14
is chute, 15 is sealed cover, CH. CH' is the vertical blade, c and c' are the horizontal blades, and M is the mixing part. Patent applicant: Nippon Steel Corporation

Claims (1)

[Claims] When agglomerating granular or powdered reduced iron or pre-reduced ore, the agglomeration raw material supplied to a pair of flat rolls is pressure-molded while applying extra pressure, and then continuously cut. A method for agglomerating reduced iron or pre-reduced ore.