JPS61223137A - Sintering operation method utilizing crude graphite - Google Patents

Abstract

PURPOSE:To obtain high thermal efficiency by kneading crude graphite produced from molten pig iron in a blast furnace with finely powdered starting materials and using the kneaded material as primary fuel for sintering in place of nearly equivalent coke breeze. CONSTITUTION:Unrefined crude graphite (a) produced from molten pig iron in a blast furnace is kneaded with dusts (b) as finely powdered starting materials in a kneader 1 after the water content is regulated to about 9%, and the kneaded material is sent to an ore storage tank 2 as primary fuel for sintering. This primary fuel is mixed with ore, secondary starting materials and coke breeze in primary and secondary mixers 3, 4, and the mixture is fed to a pallet carriage 5 as a starting material to be sintered in the form of granules. Thus, the consumption unit of coke breeze can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a sintering operation method that utilizes crude graphite generated during the casting of hot metal in a blast furnace as raw fuel for sintering.

(Conventional technology, problems) Graphite is generated during the casting of blast furnace hot metal.

There are many impurities such as carbon O (D, nipe, sio, cao, etc.), and it is possible to collect only 0 and improve the C grade and use it as a chemical raw material for electrodes, etc., but in order to increase the 0 grade, it is necessary to It has not been put into practical use because of cost problems such as the need to go through purification processes such as screening, oxidation, and high processing costs.

On the other hand, conventionally, one blast furnace was fired as raw fuel for sintering containing 0,
Dust generated in each process of steelmaking, such as sintering dust and converter dust, has been used, but blast furnace ash 00 grade is at most 3.
Even when used as a raw fuel at a concentration of about 5%, the effect is small, and when compared to ordinary coke breeze, its thermal efficiency was about 70%.

From this, the use of coarse graphite with a high zero grade has been considered, but since coarse graphite is a very fine powder, scattering during handling is a problem), so it is necessary to add water to prevent scattering. It is necessary to have grains with a moisture content of about 25%, and if crude graphite alone is used as raw material and fuel for sintering, it will cause problems such as stacking in the storage tank and increasing fluctuations in the sintering process. However, it had not yet been put into practical use.

The present invention has solved these problems. Rough graphite generated during casting of blast furnace hot metal) 1) Provided in method 1 for use as raw fuel for sintering.

(Problem t-Means and effects for solving) The present invention is a sintering operation characterized in that unrefined coarse graphite generated from blast furnace hot metal is kneaded with fine grain raw material and used as raw fuel for sintering. It's a method.

In the present invention, the fine grain raw material refers to a raw material for sintering having an average particle size of 0.5 mm or less, and contains iron.

In view of the above-mentioned problems, the inventor of the present invention has investigated various ways of using crude graphite as a raw material fuel for sintering.
By kneading with a mixer such as a Red mixer or an I1 Rich mixer.

It has been confirmed that it can be used without the problems of scattering that occur when handling coarse graphite, is more effective as a fuel than dust, and can be equivalently replaced with powdered coke.

In addition, as proposed in Japanese Patent Application No. 145887/1987, the cold strength of the upper layer of sintering is improved by spreading pre-mixed raw materials on the surface layer of the sintering bed in front of the sintering ignition furnace. It was also confirmed that the yield was improved.

(Example) Next, the present invention will be explained in detail based on examples.

[Example 1] Example 1 is a case where crude graphite is mixed and granulated with other iron ore and slag raw material in advance and used as raw fuel for sintering.

Book 1j! The examples were carried out using a DL type waste machine with a sintering area of 170 mm, and Table 1 shows examples of changes in the blending ratio of coarse graphite and fine grain raw materials and the C grade when coarse graphite is used. @iOther than graphite are raw materials. Graphite can be added up to 50% and is a good friend.

Tables 1 and 2 show the representative components of blast furnace ash and crude graphite, and Tables 2 and 3 show the sintering raw material blending ratios. Crude graphite is only 0.4% of the total.

As shown in Fig. 1, coarse graphite a is mixed with dust, which is a fine raw material, in a kneader IK with a moisture content adjusted to 9XIC, and this is used as raw fuel for sintering in the sintering ore storage tank 2. It was mixed with other ores, auxiliary raw materials and coke powder in a primary mixer 3 and a secondary mixer 4, granulated, and charged onto a pallet truck 5 as a sintering raw material.

Figure 2 shows the changes in yield, Fed, and coke blending ratio during a test in which 0.4% of crude graphite was used in the blended raw materials.

- From this, it was possible to reduce the coke blending ratio equivalent to a zero increase in crude graphite at a constant yield, and the zero substitution rate was almost 100%.

As a result, as shown in FIG. 3, the method of the present invention was able to reduce the basic unit of coke breeze.

[Example 2] Example 2 is an example in which raw fuel for sintering, which was prepared by kneading coarse graphite and dust, which is a fine raw material, was sprinkled on the surface layer of the sintering bed before ignition, as shown in Fig. 4. be. Crude graphite was kneaded and charged into a raw material ct-hog hole 6, from which a fixed amount was cut out using a quantitative cutting device 7 and uniformly spread in the width direction of the hole using a scattering plate 8 that spread the raw material in the width direction of the bed. Later, it was ignited in the ignition furnace 9 by the burner 10 using OOG as fuel.

The raw fuel C obtained by kneading crude graphite used here had the composition and properties shown in Tables 1 and 2. As a result, by spraying 7.5 Sct/t-s of raw fuel for sintering mixed with crude graphite with a C grade of 11.3% (equivalent to 1 kg/t-s of coke powder), the fifth As shown in the figure, the cold strength of the surface layer of the ICm bed was improved by 10%, and as shown in Figure 6, the yield was improved by 1.4%. Also, as shown in Figure 7, OO
The G consumption rate was also reduced by 0.5 Nd/t-8.

Table 4 Comparing the effects of this example and the case of spraying only coke powder, the results are as shown in Table 4. In this example, the C source is mixed with other raw materials, so the ignitability is reduced and the OOG consumption rate is lower. Although the improvement formula is smaller, the improvement effect (yield) is large because the rolling material using iron-rich raw materials is kept at high temperatures for a long time! ! The cost reduction in this example is greater than that in the case of single sprinkling of coke powder, and furthermore, since inexpensive crude graphite is used as the zero source, even greater cost reduction can be achieved.

(Effect of the invention) As described above, by kneading coarse 27ite with fine raw material with an average particle size of 0.5 particles or less and using it as a raw fuel for sintering, it is possible to replace coke powder on a 1:1 basis. It was confirmed that it has high thermal efficiency.

In addition, by spraying the raw fuel for sintering, which is made by kneading coarse graphite with a fine raw material with an average particle size of 0.5 m or less, on the surface layer of the sintering bed, the yield of the bed surface layer and the consumption of coke gas for ignition were reduced. .

Therefore, the present invention greatly contributes to reducing the cost of sintered ore.

[Brief explanation of drawings]

FIG. 1 is a diagram explaining the present invention in detail, and FIG. 2 is a diagram showing changes in yield, Fed, and coke blending ratio. Figure 3 is a diagram showing the effect of reducing coke powder consumption per unit. Fig. 4 shows another embodiment of the present invention, Fig. 5 shows the cold strength improvement effect of the surface layer of the sintered bed, Fig. 6 shows the yield improvement effect, and Fig. 7 shows the OOG raw material. This is the cause of the unit reduction effect. l...kneader, 2...sintered ore storage tank, 3...primary mixer, 4...secondary mixer, 5...pallet truck, 6...hopper, 7... Quantitative cutting device, 8...
- Spreading plate, 9... Ignition furnace, 10... Burner. Agent Patent Attorney Masamitsu Aki Sawa and 2 others ff 3 Mushroom 4 Afro Voluntary Procedure Amendment April 30, 1985 Indication Patent Application No. 1987-65565 for the Licensed Agency Ushinomiya Case Name of the Invention: Coarse graphite utilization firing Relationship with the case of the person making the amendment Application Address 2-6-3 Otemachi, Chiyoda-ku, Tokyo Name (665) Nippon Steel Corporation, Agent

Claims (1)

[Claims] (1) A sintering operation method characterized in that unrefined coarse graphite generated from blast furnace hot metal is kneaded with fine grain raw material and used as raw fuel for sintering.