JPH07157827A - Production of non-burning agglomerate - Google Patents

Abstract

PURPOSE:To produce non-burning agglomerate being simply useable to a blast furnace in a short period by forming fine grain-state raw material for blast furnace into lump- state while using molasses as the binder. CONSTITUTION:Raw material dust 30 having <=0.5mm of fine powder-state of iron ore, lime, etc., recovered with a dust collector and minus sieve sintered ore having <=4mm produced in a fine returned ore and the carrying process of the sintered ore for blast furnace are charged into blending vessels 31-33. Each suitable quantity is discharged with a fixed quantity discharging device 26 and the suitable water is added in a first mixer 34 and a second mixer 35 through a belt conveyor 12 and kneaded. The mixed material is supplied into blending vessels 36 and segmented together with the fine grain 43 in the product produced through a vibrating sieve 42 in the last process on a belt conveyor 26 with a fixed quantity segmenting device 24 at a prescribed ratio. The molasses as the binder from a binder adding device 38 is added with a mixer 37 so as to contain at 1-6%, and after sufficiently kneading by a kneader 39, this kneaded material is agglomerated by a forming machine 40 providing two rolls. The lumpy raw material for blast furnace having excellent collapse strength is obtd. through the vibrating sieve 42 and the fine grain of the minus sieve is also reused as the fine returned ore.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a non-calcined agglomerated ore suitable as a raw material for a metallurgical reaction furnace such as a blast furnace or a direct reduction furnace.

[0002]

2. Description of the Related Art For example, as shown in FIG. 8, when a sintered ore is manufactured, a powdery iron ore having a particle size of approximately 8 mm or less is mixed with a solvent such as quick lime or limestone in a mixing tank 1 to obtain a basicity ( The value of CaO / SiO ₂ ) is adjusted to be about 1.0 to 2.5, and powder coke for fuel is further added. Then, a required amount of water is added to and mixed with the drum type mixers 2 and 3 and then granulated, and then charged into the surge hopper 6. Next, the granulated sintering raw material is cut out by the roll feeder 7 and fed to the pallet of the sintering machine 4 together with the bedding ore already cut out immediately before from the bedding hopper 9, ignited, and fired. It moves in the direction of the mining department while the connection is being made. After sintering, coarse crushing,
After a cooling and sieving process, a product having a particle size of approximately 4 to 50 mm is made into a product, and this product is put into a blast furnace, while a particle size of 4 mm or less is returned ore and refired in a sintering process. In addition, the powder of 4 mm or less generated in the process of conveying the blast furnace, etc. removed by a sieve provided on the way is usually returned to the yard as a powder under the sieve (undergarden powder) and is used as a part of the sintering raw material. It is re-fired in the same manner as return ore. The returned ore and undersize powder have been already sintered in the sintering process, and recirculating them is extremely unreasonable in terms of firing cost and transportation cost.

Therefore, there is provided a manufacturing method for producing a product which can be put into a nodule and charged into a blast furnace or the like. For example, JP-A-58-123839 discloses 20-25.
Disclosed is a sinter return ore lumping method in which ball-like Portland cement, to which wt% water has been added and kneaded, is used as a core, and return slag is adhered and bonded to this to be slag. Has been done.

[0004]

However, in the above-mentioned conventional method, since it takes a long time for the cement to harden and develop its strength, a curing period of at least 48 hours or more is required. In addition, it is necessary to secure a bunker or a yard space for product curing.

In order to compensate for such drawbacks, Japanese Patent Publication No. 58-
Although a continuous rapid curing method is proposed in Japanese Patent Publication No. 53054 and Japanese Patent Publication No. 59-33648, such a curing method requires many auxiliary equipment such as a curing tower and a steam gas blowing device to be installed. The area is large and the equipment cost is high.

The present invention has been made in order to solve the above-mentioned problems, and is one or two kinds of sinter reclaimed or sintered sieving powder (blast furnace product sieving powder, warehousing product), An object of the present invention is to provide a method for producing a non-calcined agglomerated ore that can be efficiently agglomerated without recirculating a mixed powder of dust having a relatively smaller particle size than this, and using a small amount of auxiliary equipment. To do.

[0007]

The method for producing a non-sintered agglomerated ore according to the present invention comprises one or two types of sinter reclaimed or sintered sieving powder (blast furnace product sieving powder, warehousing product). Mixing powder of dust with a relatively finer particle size than this, kneading by adding molasses or its diluent as a binder capable of developing strength required for transportation, handling, etc., by kneading, granulating or molding Agglomerate with a machine.

[0008]

As shown in FIG. 2, when the fine particle dust 53 is mixed with the mixture of the sintered return ore 51 and the sintered undersize powder 52, the fine dust 53 is formed between the particles of the coarse returned ore 51 and the undersize powder 52. 53 is filled, the overall formability and bondability are improved, and the strength of the agglomerated ore is increased.

FIG. 3 is a characteristic diagram showing the relationship between various binder materials, with the horizontal axis representing temperature and the vertical axis representing viscosity. In the figure, curve A shows molasses, curve B shows dextrin 1, curve C shows alcohol waste solution 1, curve D shows alcohol waste solution 2, and curve E shows dextrin 2. As is clear from the figure, molasses used as a binder has a high viscosity itself and brings about a binding action, but it solidifies in a short time due to evaporation of water after the compression molding process or after molding, and shows a strong bonded state. The liquid transferable limit is at a viscosity of 1 × 10 ³ , and a liquid having a viscosity exceeding this cannot substantially pass through the transport pipe.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a process flow diagram showing a method for producing a non-fired agglomerated ore according to an embodiment of the present invention.
In this embodiment, the briquette manufacturing process using a molding machine will be described, but it goes without saying that the same effect can be obtained by using a granulating machine instead of the molding machine (the product becomes pellets). Sintered ore, sintered undersize powder and dust are stored in the mixing tanks 31 to 33, respectively, and each fixed quantity cutting device 2
0 is cut out on the conveyor 12 so as to have a predetermined mixing ratio. It should be noted that the fine particles collected by a dust collector or the like are used as the dust, which is transferred from the small hopper 30 to the conveyor 11 and is conveyed by the conveyor 11 to the first mixing tank 31.
To be shipped to. These raw materials are transported to the first mixer 34 and the second mixer 35 by the conveyors 12 and 13 and mixed. If necessary in this kneading step, humidity control (addition of water) may be performed. further,
The raw materials are transported to the receiving compounding tank 36 via the conveyors 14 and 15.

In the generated powder storage tank 43, the product generated powder that has been sieved by the grizzly or shaking sieve 42 is stored, and these are cut out by the quantitative cutting device 24 and mixed into the raw material at a predetermined mixing ratio. And the binder addition equipment 3 to this
The molasses sent from No. 8 is mixed in a mixer 37 (usually a hagmill), and if necessary, the humidity is adjusted and kneaded. From the viewpoint of cost, it is desirable that the amount of the binder (molasses) added be as small as possible. In this embodiment, the molasses addition amount is set to 1 to 6% by weight. The lower limit of the amount of molasses added is set to 1% by weight because if it is less than 1% by weight, moldability and strength after molding deteriorate. On the other hand, the upper limit of the molasses addition amount is set to 6% by weight, because if it exceeds 6% by weight, it takes time for the binder to solidify, and the crush strength immediately after molding is lowered.

Next, the mixed raw material supplied from the kneader 39 to the molding machine 40 is agglomerated and discharged through the grizzly or shaking sieve 42. In this case, it is desirable that the roll forming pressure be in the range of about 1.0 to 1.5 ton / cm. In this way, the products described in (a) and (b) below could be obtained. (A) The briquette products of Examples 1 to 5 have a particle size of 25 mm
It becomes a 45 mm sieving product. (B) The size of the product agglomerate after molding is 50 mmφ ~
Those with a diameter of 1 mm are raw materials for the blast furnace.

Table 1 shows the particle size distribution of the sintered reclaimed ore used in the examples of the present invention. Table 2 shows the chemical composition of the sintered slag ore used in the examples. Table 3 shows the particle size distribution of the sintered undersize powder used in the examples. Table 4 shows the chemical components of the sintered undersize powder used in the examples. Table 5 shows the particle size distribution of the dust used in the examples. Table 6 shows the chemical components of the dust used in the examples. In addition, the component indication of each composition is% by weight.

[0014]

[Table 1]

[0015]

[Table 2]

[0016]

[Table 3]

[0017]

[Table 4]

[0018]

[Table 5]

[0019]

[Table 6]

Table 7 shows the main components (% by weight) of molasses used as a binder. Table 8 shows the raw material mixing conditions of Examples 1 to 5, respectively. In addition, in Table 8, the addition amounts of the binder and water are the ratios of the sinter reclaimed powder, the sinter undersize powder, and the dust to the total weight (100%) of the powder raw material.

[0021]

[Table 7]

[0022]

[Table 8]

Using the raw materials and binders shown in Tables 1 to 7 above and using mixed raw materials prepared in the formulations shown in Table 8, molded briquettes 45 to 25 mmφ
The crush strength and the drum strength (DI strength) were examined. The results are shown in FIGS.

In FIGS. 4 and 5, the horizontal axis represents the elapsed time (minutes) after molding, and the vertical axis represents the crushing strength (kg / kg) of the briquette.
6 is a graph showing the results of examining the curing rate for Examples 1 to 3 and Examples 4 to 5, respectively. In the figure, curve F shows the result of Example 1, curve G shows the result of Example 2, curve H shows the result of Example 3, curve J shows the result of Example 4, and curve K shows the result of Example 5. The results are shown below.

6 and 7, the horizontal axis represents the elapsed time (minutes) after molding, and the vertical axis represents the product DI strength (+15 mm%). Examples 1 to 3 and Examples 4 to 5, respectively. FIG. 6 is a graph showing the results of examining changes in drum strength with respect to FIG. In the figure, the curve L shows the results of Example 1, the curve M shows the results of Example 2, the curve N shows the results of Example 3, the curve P shows the results of Example 4, and the curve Q shows the results of Example 5. The results are shown below.

As is clear from these results, the crush strength of 30 kg or more, which is already required for transport, was obtained 20 minutes after the molding and the DI strength of 80% was obtained. In addition, the DI strength reaches the upper limit value one hour after the molding, and does not substantially increase further. As described above, in this embodiment, it is possible to obtain a strong agglomerated ore without requiring long-term curing time and installation of auxiliary equipment required for rapid curing.

[0027]

According to the method of the present invention, compared with the conventional method,
The curing time is shortened, the curing space is also saved, and it is possible to agglomerate sinter return ore, sintered sieving powder, dust, etc. without using many auxiliary equipment required for shortening the curing time. .

[0028] Further, since the raw material which was originally subjected to the cyclic reprocessing and re-firing such as the sintered reclaimed mineral powder, the sintered undersize powder, and the dust can be agglomerated and used as a raw material for the blast furnace, etc. It is possible to reduce the binding cost and various basic units, the sintering equipment cost, and the maintenance cost. In addition, ripple effects such as effective use of resources and contribution to environmental conservation can be brought about.

[Brief description of drawings]

FIG. 1 is a process flow diagram showing a method for producing a non-fired agglomerated ore according to an embodiment of the present invention.

FIG. 2 is a structural conceptual diagram of an agglomerate produced by the method of the present invention.

FIG. 3 is a characteristic diagram showing a relationship between viscosity and temperature of various binder materials.

FIG. 4 is a graph showing the crush strength of a product in each example of the method of the present invention.

FIG. 5 is a graph showing the crush strength of a product in each example of the method of the present invention.

FIG. 6 is a graph showing the drum strength (Dl) of the product in each example of the method of the present invention.

FIG. 7 is a graph showing the drum strength (Dl) of the product in each example of the method of the present invention.

FIG. 8 is a process flow diagram for explaining a conventional sinter production process.

[Explanation of symbols]

31, 32, 33, 36, 43 ... Blending tank, 34, 35 ...
Mixer, 37 ... Mixer, 38 ... Binder addition equipment, 4
0 ... Molding machine, 41 ... Product tank, 42 ... Shaking sieve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masanori Nagano 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Pipe Co., Ltd. (72) 1-2-1 Marunouchi, Chiyoda-ku, Tokyo No. Nippon Steel Pipe Co., Ltd. (72) Inventor Kazumasa Wakimoto 1-2-2 Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Pipe Co., Ltd. (72) Atsushi Sakai 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Pipe Co., Ltd. (72) Inventor Kenichi Nemoto 1-2-2 Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Pipe Co., Ltd. (72) Inventor Tomio Kamoshida 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Japan Inside the Steel Pipe Co., Ltd. (72) Minor Ueda Minoru Ueda 429, Shinjo-dori Shijo-Kamikanatancho, Shinmachi-dori, Nakagyo-ku, Kyoto Prefecture Keihan Co., Ltd. (72) Inventor Kiyoshi Omizo Cabinet Office Kyoto Nakagyo-ku Shinmachidori Shijo Agaru Komusubidana-cho, 429 address, Inc. in the Keihan

Claims (2)

[Claims] 1. A mixed powder of 1 or 2 kinds of sinter reclaimed or sintered sieving powder (blast furnace product sieving powder, warehousing product) and dust having a finer particle size than 1 to 6 Add 1% by weight of molasses or diluent containing the above amount of molasses as a binder and knead.
A method for producing a non-calcined agglomerated ore, which comprises agglomeration as described above. 2. The non-calcined agglomerated ore according to claim 1, wherein the dust is dust containing dust containing iron components having a particle size of 0.5 mm or less, which is collected by an environmental dust collector in an iron mill. Manufacturing method.