JPH03249138A - Operation method for sintering - Google Patents

Abstract

PURPOSE:To make improvement in the pelletizing property of sintering raw materials and to produce sintered ore with high productivity and product yield by charging the coarse particles generated by the classification of returns into a blast furnace and using the fine grains as the raw materials for pelletizing at the time of pelletizing and sintering the raw materials of the sintered ore for the blast furnace. CONSTITUTION:The respective powder raw materials are taken at prescribed ratios out of a storage tank 1 for powdery iron ore, limestone, coke, etc., and a storage tank 2 for the returns of the sintered ore and are mixed with water in a primary mixer 3. The mixture is pelletized in a secondary mixer 4 and is charged to a surge hopper 5, from which the mixture is supplied to a sintering machine 6 and is thereby sintered. The sintered ore is properly crushed by a crushing machine 7 and is sieved by a primary screen 10 after cooling with a cooler 8. The plus sieve is charged to the blast furnace and the minus sieve is sieved by a secondary screen 11, the plus sieve of which is charged to the blast furnace and the minus sieve is sieved by a tertiary screen 12. The plus sieve thereof is charged to the blast furnace and the coarse grains 21 of 0.5 to 1.0mm of the minus sieve are blown by air flow 22 and are supplied to the return tank 2 by a conveyor 19. The minus sieve below these sizes is supplied by a conveyor 19 to the secondary mixer 4 and is used as the raw material for pelletizing. The pseudo particle sizes of the sintering raw materials increase and the air transmissivity of the sintering raw material layer is upgraded. The productivity of the sintered ore is thus increased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] This invention relates to a sintering operation method for improving the granulation properties of sintering raw materials.

[Prior Art] In the production of sintered ore, one of the important requirements is to improve the granulation properties of raw materials in order to improve productivity and quality. Various techniques have been developed and implemented in the past in order to improve granulation properties. Techniques for improving the granulation properties of raw materials include the following.

■ Binder (bentonite, quicklime, cement, etc.)
(For example, Japanese Patent Application Laid-Open No. 61213328). (For example, Japanese Patent Application Laid-open No. 61213328). (2) After primary granulation of the sintering raw material, a method in which pellet phyto and water are added and mixed to form second modified granules.

(For example, JP-A-58-64325) ■ Method for controlling the rotation speed and rotation direction of a rotating body provided inside a drum mixer (For example, JP-A-60-52535) [Issues to be solved] However, the method (■) increases the production cost of sintered ore because the binder is expensive, the method (■) has problems with the supply of pellet feed, and the method (■) is not very effective. There is a problem. Furthermore, conventionally, iron ore powder and the like and return ore of all particle size ranges were mixed in a primary mixer, but it has been found that the coarse part of the return ore does not contribute to the granulation of the sintering raw material. Therefore, the present invention aims to provide a sintering operation method that improves the granulation properties of sintering raw materials by changing the conventional method of using return ore.

[Means for Solving the Problems] The present invention aims to achieve the above-mentioned objects, and involves mixing and granulating iron ore powder, a solvent, coke powder, etc., and charging the mixture into a sintering machine. This sintering operation method is characterized in that the unsieved powder of sintered ore is classified to a predetermined particle size, and the fine powder is charged into a secondary mixer, mixed, and granulated.

It is preferable to set the classification particle size in the range of 0.5 to 1.0 fins. 6. If the classification particle size becomes less than 0.5 fins, the amount of fine powder collected will decrease and the granulation effect will decrease.
Moreover, if the ratio exceeds 1.0, coarse particles will be mixed into fine powder, reducing the granulation effect. Alternatively, the fine powder of the return ore may be mixed with collected dust and then fed into the secondary mixer.

[By classifying the return ore and feeding the fine powder into the secondary mixer, the average diameter of the pseudo particles of the raw material after the secondary mixing increases (see Figure 3), and the raw material layer on the sintering machine This improves the air permeability and increases the production rate (see Figure 4).

[Example] Examples of the present invention will be described in detail below. In FIG. 1, ore powder, limestone powder, and coke powder are cut out from a storage tank group 1, return ore is cut out from a return ore storage tank 2, and water is added and mixed in a primary mixer 3. The raw materials mixed in the primary mixer 3 are granulated in a secondary mixer (or drum pelletizer) 4, and then fed into a surge hopper 5.
It is charged into a sintering machine 6 via a roll feeder to a predetermined thickness and sintered. Sintered lump discharged from the ore discharge section of #l sintering machine 6 (
The sinter cake) is crushed by a primary crusher 7, cooled by a cooler 8, and then conveyed to a primary screen 10. The upper part of the primary screen 10 (sieve mesh 50 am) is transported to the blast furnace, and the lower part of the sieve is transported to the secondary screen 11. 1
The under sieve of the secondary screen 10 is sized by a secondary screen 11 (sieve mesh 15 mm), the upper sieve of the secondary screen 11 is conveyed to a blast furnace, and the under sieve is conveyed to a tertiary screen 12 (sieve mesh 8 mm). The sieve surface of the tertiary screen 12 is conveyed to the blast furnace via a conveyor 17. By the way, in the past, the entire amount of the under-sieve of the tertiary screen 12 was transferred to the return ore storage tank 2, but in the present invention, the under-sieve hopper of the tertiary screen 12 is used as an airflow gravity classifier as shown in FIG. The grains are classified into coarse grains and fine grains. In Fig. 2, 12 is the tertiary screen, 13 is the under-sieve hopper, and 14 is the under-sieve hopper 1.
An air flow blowing duct 15 is attached to the side surface of 3, and a fine grain hopper 15 is connected to the side surface of the under-sieve hopper 13, the upper part of which is open to the under-sieve hopper 13. 16 is an airflow exhaust duct. The under sieve of the tertiary screen 12 is
Airflow 22' blown from the airflow blowing duct 14 (in this case, the gas blown in is generally atmospheric air)
- classified into granules 21 and fine particles 20, coarse particles 21
gets on the conveyor 19 from the discharge port of the under-sieve hopper 13,
The return ore is fed into the primary mixer 3 through the storage tank 2, and fine particles 20
gets on the conveyor 18 from the discharge port of the fine grain hopper 15,
It passes through the storage tank 16 and is fed into the secondary mixer 4.

Table 1 shows the results of particle size analysis of the under sieve of the tertiary screen, and Table 2 shows the results of classification by air flow (classified particle size: 0.5 ■!
I) shows the particle size distribution of the recovered fine powder. Since the production unit of return ore is approximately 190 kg/T, when the classification particle size is 0.5+i+a, from the results in Table 1,
Approximately 47 kg/T of fine powder is collected. This corresponds to 3.2% of the sintering mixed raw material.

Figure 3 compares the average diameter of pseudo particles of the sintered raw material after the secondary mixer between the conventional method and the method of the present invention. It's as big as a dragon.

Figure 4 shows a comparison of production rates.As the pseudo particle size of the sintering raw material increased and the air permeability improved,
The method of the present invention increased T/m''h compared to the conventional method.

Table 1 [Effects of the Invention] Since the present invention is configured as described above, it is possible to obtain
This method has the effect of lowering manufacturing costs and improving productivity than the method of adding a binder.

[Brief explanation of drawings]

Fig. 1 is a sintered ore manufacturing process diagram in which the process of the present invention is carried out, Fig. 2 is a diagram showing an air classifier under the tertiary screen,
FIG. 3 is a graph comparing the average diameter of pseudo particles after granulation between the conventional method and the method of the present invention, and FIG. 4 is a graph comparing the production rate between the conventional method and the method of the present invention. 2... Return ore storage tank, 4... Secondary mixer 12... Tertiary screen, 13... Under-sieve hopper 14... Airflow blowing duct, 15... Fine grain hopper 16... Airflow Exhaust duct, 20...fine particles, 21...coarse particles, 22...airflow.

Claims (3)

[Claims] (1) In a sintering operation method in which iron ore powder, solvent, coke powder, etc. are mixed, granulated, charged into a sintering machine, and fired, the sintered ore undersieve powder is classified to a predetermined particle size and finely granulated. A sintering operation method characterized by introducing powder into a secondary mixer, mixing and granulating it. (2) The sintering operation method according to claim 1, wherein the classified particle size is in the range of 0.5 to 1.0 mm. (3) The sintering operation method according to claim 1, wherein the fine powder and collected dust after classification are introduced into a secondary mixer.