JPH03219027A - Granulating method of sintering raw material - Google Patents

Abstract

PURPOSE:To form granulated body having a little moisture and excellent strength by making a raw material-mixed powder coming into a kneader band-like shape flow and spraying water from both sides thereof at the time of granulating the mixed powder as the raw material of sintered ore for blast furnace after kneading with the kneader. CONSTITUTION:At the time of manufacturing the sintered ore used for the blast furnace when the raw material 1 composed of the mixed powder of powdery iron ore, returned ore, binder of lime, etc., slag-making agent, and coke is charged to the kneader 31 as a band-state while conveying with a belt conveyor 3, the moisture is added with two water spraying devices 4, 4a from the front surface and rear of band-state mixed raw material. This powdery raw material is vibrated with an exciting machine 32 and formed to flaky-state having strong bonding force with plural incorporated compacting medium 34 and this is charged to the next granulating machine 41. This granulating machine 41 is vibrated with an exciting machine 42, to give the flaky mixed raw material the vibration, and by rolling, the flaky mixed raw material is granulated. This granulated raw material is charged to a DL sintering machine to manufacture the sintered ore for blast furnace. The granulated sintering raw material having excellent strength can be manufactured with the mixed raw material having a little moisture content and the sintered ore can be manufacture at a low sintering cost.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for granulating a sintering raw material in which iron ore or the like is fed to a DL type sintering machine to sinter the sintered ore. The present invention relates to a method for granulating sintered raw materials that enables the granulation of high-strength mini-pellets by adding a small amount of water.

[Prior Art 1] If 10% or more of fine iron ore containing 60% or more of particles less than 60 μm is mixed into the sintering raw material, the permeability of the sintering bed will be inhibited and productivity will be reduced.

In addition, in order to improve the air permeability of the sintered bed, a large amount of binder (quicklime, slaked ash, etc.) is required, leading to problems such as an increase in sintering costs.

Granulation techniques for blending approximately 40% by weight of finely divided iron ore include open grinding and kneading granulation and molding methods (Japanese Patent Publication No. 43-625
No. 6) is known. This method uses ball mill, mouth and
After grinding the raw materials and adjusting the moisture content in a dry mill or other wet grinding mill, raw pellets are granulated using a vertical type, one cylinder type, or other type of granulator. Even in this method, there is no confusion! Moisture adjustment at 1 im is very important. On the other hand, the amount of water required for granulation varies depending on the raw materials used and must be appropriately adjusted. In addition, excessive water content not only causes a decrease in the strength of the granules, but also causes excess moisture in the upper layer of the sintered layer to condense in the middle and lower layers during the sintering process, causing the granules to collapse and forming during sintering. This results in deterioration of air permeability.

In the above-mentioned hot grinding and kneading granulation and forming method, there is no mention of a specific method for adjusting the moisture content depending on the ore brand, which is necessary to granulate uniform high-strength mini pellets. However, in the above-mentioned conventional technology, the amount of water added is still large (therefore, the granulation strength cannot be said to be sufficient, and it cannot be said that it will lead to an improvement in the productivity of sintered ore. In other words, the above-mentioned When granulating using prior art methods, especially when using ores with poor granulation properties, the apparent density is high (and the crushing strength of the poles is low) unless moisture control and proper watering methods are used. It was difficult to make high quality granules.

Furthermore, in order to improve the strength of Greenpol granulated by the above method, a vibratory kneading and granulating device has been developed in which a vibration function is added to the mixer and granulator, but the addition of water is not determined in advance. The green balls were not strong enough because the amount of water was supplied to the kneading machine and the granulating machine.

[Problem to be Solved by the Invention 1] In view of the above-mentioned circumstances, the present inventors have conducted various studies and found that a mixed wire is created in which a large number of consolidation media are given circular motion vibrations and strongly excited, and raw materials are supplied to and kneaded. By devising a method of sprinkling water at the appropriate position for various brands of raw materials in the machine, it has become possible to reduce the amount of water added to various brands of raw materials, making it possible to process fine iron ore in multiple machines. It has been found that it is possible to produce uniform and strong granules with high efficiency.6 It is an object of the present invention to provide such a method.

[Means for Solving the Problems 1] The present invention is a method for suitably granulating fine iron ore (D Jl material is charged into a compaction plasticizing kneading space containing a compaction medium, and an excitation force is applied. The sintered raw material is made into flakes by vibration compaction kneading. This is a sintering raw material granulation method characterized by supplying the sintering raw material falling in a band shape to the raw material charging port of a machine and sprinkling water in the form of a spray from both sides of the falling belt-shaped sintering raw material.

[Function 1] The present invention is a method of supplying optimum moisture to the sintering raw material when granulating the sintering raw material with a vibrating cross-wire granulation device consisting of a cross-wire machine and a granulator. The water is added in the form of a spray from both sides of the sintering raw material conveyed from the belt conveyor while it falls into the mixer. Since the voids are dense while the sintering raw material falls, an excessive amount of water is not required, and water can be uniformly supplied to the entire sintering raw material by adding a small amount of water. The raw materials supplied with the minimum amount of water in this way are subjected to comprehensive actions such as compaction, shearing, transfer, crushing, kneading, and mixing by the compaction medium in the mixer, which acts to equalize and spread the water on the surface of the particles. As a result, the particle group becomes a capillary region, turns into flakes with strong bonding force, and becomes plasticized.

Furthermore, in this mixer, water adheres to the surface of the small granules formed by supplying water in the form of a spray as needed, and undergoes the comprehensive action of the above-mentioned consolidation, kneading, etc. Uniform distribution of moisture within the granules and enlargement of the particles are achieved.

Next, a granulator is used to produce this compacted and plasticized flaky material.
When 1 itself is transferred by strong vibration, the packing density increases, moisture permeates to the surface, adhesion due to this moisture, and particle size growth occurs, making it possible to obtain a high-strength granulated product.

By supplying moisture to the raw material in this way, it becomes possible to granulate with a minimum amount of moisture.

[Example 1] FIG. 4 shows an example of an apparatus that can suitably carry out the method of the present invention. 2 and 3 are cross-sectional views of the drum 31 of the mixer and the drum 41 of the granulator, respectively. First, the vibrating kneading and granulating device will be explained. This device has a configuration in which a vibrating kneader 30 and a vibrating granulator 40 are arranged in series. The vibrating kneading machine 30 is shown in FIG. In this way, a compaction contact body 34 is built into the drum 31, and
are mounted on both sides of the drum 31 and supported on the foundation by springs 33. The S applying machine 32 is configured to be able to vibrate right and left in synchronization, and cooperates with a spring 33 to apply circular vibration to the consolidation medium 34.

As shown in FIG. 3, the vibratory granulation unit 40 has vibrators 42 mounted on both sides of a drum 41, and is supported on a foundation by springs 43. The vibrator 42 and the spring 43 work together to apply circular vibrations to the sintering raw material, causing it to roll and granulate.

In this apparatus, as shown in FIG.
, 4a. This water sprinkler 4.4a is used to evenly add moisture to the sintering raw material.

Note that FIG. 1(a) is a perspective view, and FIG. 1(b) is a sectional view.

Table 1 shows the characteristics of green pole and sintered ore produced by the method of the present invention and the conventional method. Since the sintering raw material has many fine particles, it is pre-treated by adding moisture to create pseudo-granules before firing. It is said that an average diameter of pseudo particles of about 3 to 5 mm is optimal for sinterability. +10
If there are too many mm-sized pseudo particles, the air permeability will be too good, and the heat retention necessary for melting will not be achieved sufficiently, resulting in poor product yield. on the other hand.

- If there are many pseudo particles of 1 mm, air permeability deteriorates, sintering time increases, and productivity deteriorates. Therefore, the greater the particle size ratio of 1=10 mm in the particle size structure of the pseudo particles, the better the sinterability. On the other hand, it is necessary to increase the strength of the pseudo-particles in order to reduce pseudo-particle collapse in the moisture condensation zone during sintering. In the conventional method, since the water content is non-uniform, some parts have a lot of FPL water and some parts do not, and the particle size structure also becomes non-uniform.

If you try to obtain an appropriate particle size composition, the amount of water left behind will increase. An increase in the amount of water sprinkled is not preferable because it increases the disintegration of pseudo particles during the sintering process and impedes 1 air permeability (JPU).

Here, 1 air permeability [JPU] is calculated by formula (11), and the larger the value, the better the air permeability.

Table 2 shows a comparison between the apparatus used in the method of the present invention and the conventional method.

here.

F: Suction air volume (Nrn'/m i 'n)A Nigeshi8 area (lT1'') H: Bed layer thickness (mm) S: Suction air pressure (mm H20) According to the present invention, the amount of water is minimized and the raw material It was possible to provide uniform moisture to the material, and the granulation and sintering properties were able to be extremely improved.

(b) [Effect of the invention 1 According to the present invention, it is possible to carry out ja li with the minimum amount of water, and the amount of water in the water condensation zone during the sintering process is reduced, so that the granules are The cause of the obstruction to air permeability was solved, and it became possible to reduce the amount of binder transport needed to maintain strength, improve productivity, and reduce sintering costs.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an apparatus that can suitably carry out the present invention, in which FIG. 1(a) is a perspective view, FIG. 1(b) is a sectional view, and FIG.
FIG. 3 is an explanatory diagram of a cross section of a mixer, FIG. 3 is an explanatory diagram of a cross section of a granulator, and FIG. 4 is an explanatory diagram of a vibrating kneading and granulating apparatus comprising a mixer and a granulator.

Claims (1)

[Scope of Claims] 1. When granulating a sintered raw material using a vibrating kneading and granulating device consisting of a vibrating kneader and a vibrating granulator, the sintered raw material is fed into a strip shape into a raw material charging port of the kneader. A method for granulating a sintering raw material, which comprises supplying the sintered raw material in a falling manner, and spraying water in the form of a spray from both sides of the falling band-shaped sintered raw material.