JPH04334577A - Sieving method of granule mass by vibration sieve - Google Patents

Abstract

PURPOSE:To sieve a material in desired particles sizes constantly stably even the particle sizes and the amount of the granule masses of a material supplied to be sieved by a vibration sieve having upper and lower double sieving nets. CONSTITUTION:In the case that granule masses of a material are supplied to the upper side sieving mesh of a vibration sieve having upper and lower double sieving nets and the granule masses are sieved in desired particle sizes by both upper and lower sieving nets, the size of the meshes of the upper side net is altered and adjusted to make the load factor of the lower side sieving net be 40-60%.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for sieving powder agglomerates such as sintered ore and coke to be charged into a blast furnace.

0002

[Prior art] At a steelworks, sintered ore is sintered and sized in a sintering factory, coke is carbonized and sized in a coke factory,
Iron ore transported from the yard is temporarily stored in each hopper (ore storage) installed near the blast furnace, and a predetermined amount is cut out from the hopper according to the request of the blast furnace and charged into the blast furnace via a relay tank. is being carried out.

For example, sintered ore stored in a hopper (normal particle size composition: 10 to 14% is 50 to 35 mm)
, 35-25mm is 14-16%, 25-10m
m is 44 to 42%, 10 to 5 mm is 26 to 22%
As shown in Japanese Patent Publication No. 57-45287, one stage of sieve screen is installed below the hopper to prevent particles from getting mixed in during the grading process or being broken and powdered during transportation. A vibrating sieve with a
After removing particles with the following particle sizes, the blast furnace is charged. On the other hand, changes in the operation rate of the sintering factory (
In other words, adjusting the production amount by changing the amount of raw material charged or the firing time) affects the quality of the sintered ore, especially the strength, so the average particle size and particle size composition of the sintered ore transported and stored in the hopper are Varies significantly.

[0004] Therefore, the average particle size of the sintered ore supplied to the vibrating sieve having the single-stage sieve screen fluctuates widely, and it is not possible to follow this variation and obtain a predetermined sieving efficiency. A large amount of sintered ore with a particle size of
There was a problem that a large amount of sintered ore with a particle size of m or more was returned to the sieve and the cost increased.

[0005] For this reason, as proposed in Japanese Patent Application Laid-open No. 57-99379 and Japanese Patent Publication No. 63-20590, a two-stage mesh sieve having two screens in the height direction is used, and the upper sieve is Some attempts have been made to solve the above problem by fixing the mesh of the upper sieve to be larger than the mesh of the lower sieve (lower sieve) and performing sieving in two stages.

[0006]

[Problems to be Solved by the Invention] However, even this two-stage mesh sieve was not sufficient. In other words, when the operating rate of the sintering factory increases, the strength of this two-stage mesh sieve decreases due to insufficient sintering, and the average particle size of the sintered ore supplied to this vibrating sieve becomes finer. The amount of sintered ore passing through and falling onto the lower sieve screen varied greatly, making it impossible for the lower sieve screen to sufficiently remove particles with a predetermined particle size (5 mm) or less.

[0007] In view of the above-mentioned problems, the present invention solves the problem by using a two-stage sieve screen even if the particle size structure of the powder aggregates such as sintered ore from the sintering factory or yard or coke from the coke factory changes. The object of the present invention is to constantly and stably sieve particles to a desired particle size using a vibrating sieve having the following characteristics.

[0008]

[Means for Solving the Problems] The present invention has been made to solve the above problems, and its characteristic means is that a material to be sieved is placed on the upper screen of a vibrating sieve having two tiers of sieve screens, upper and lower. When supplying a powder aggregate and sieving the powder aggregate to a predetermined particle size using both upper and lower sieve screens, the above-mentioned Change and adjust the mesh size of the upper sieve to set the load factor of the lower sieve to 40.
This is a method for sifting powder and granule agglomerates using a vibrating sieve, which is characterized in that the sieve is set to 60%.

[0009] However, the load factor α is determined by, for example, the following formula (1) or (
2). α=K1・(SM3−SM2)/(SM
1-SM 2)×100...(1) However, K 1:
Constant, SM 1: Average particle size of powder aggregates on the sieve of the upper sieve screen, S
M 2: Average particle size of powder particles on the sieve of the lower sieve screen, SM 3:
This is the average particle size of the mixed powder agglomerates on the upper sieve screen and the lower sieve screen. α=K2・WU/(XU+WU) (2) However, K2: constant, WU: amount of powder particles on the sieve of the lower sieve screen, X
U: The amount of powder agglomerates on the sieve of the upper sieve screen.

0010

[Function] The present inventor conducted various experiments on the most efficient method of sieving sintered ore in the form of powder aggregates to a desired particle size using a vibrating sieve equipped with two upper and lower sieve screens.
As a result of the study, the load factor α of the lower sieve shown in the above formula (1) or (2) and the sieving efficiency η of the lower sieve (η = amount of sintered ore below the sieve of more than 5 mm/supplied to the lower sieve) There is a relationship shown in Figure 1 between the amount of sintered ore (more than 5 mm) and the amount of sintered ore supplied to the upper sieve screen, and the sieve efficiency η is the best when the load factor α is 40 to 60%. It has been found.

Furthermore, the mesh size of the sieve screen of the vibrating sieve,
The relationship between the average particle size of the sieved sintered ore and its amount was investigated. As a result, the size of the mesh of the sieve screen and the average particle size of the sintered ore passing through it have the relationship shown in Figure 2, and
The relationship between the mesh size of the sieve screen and the amount of sintered ore passing through it is shown in FIG.

For this reason, for example, when the operating conditions in a sintering factory change, the sintered ore on the upper and lower screens of the vibrating sieve is sampled and the average particle size and amount of each are measured. By substituting the measured values into the above equations (1) and (2), the mesh size of the upper screen is changed and adjusted so that the lower screen load factor is from 40 to 60%, preferably 50%. This makes it possible to efficiently and accurately sieve and return ore of particle sizes outside the requirements of the blast furnace from the sized sintered ore supplied from the sintering factory.

[0013]

Embodiment An embodiment of the present invention will be explained below. Figure 4
1 is a simplified diagram showing the transport route until the sintered ore produced at the sintering factory is charged into the blast furnace. In the figure, 1 transports the sintered ore produced at the sintering factory S to the ore storage 2. belt conveyor,
Reference numeral 3 denotes a vibrating sieve that sieves the sintered ore cut out from the ore storage 2 as a hopper into 5 mm or more and 5 mm or less, and has an upper sieve screen A and a lower sieve screen B. 4 is a belt conveyor that conveys the sintered ore on the sieves (more than 5 mm) of the upper sieve screen A and the lower sieve screen B from the weighing hopper 10 to the relay tank 5; and 6 is the belt conveyor that conveys the sintered ore cut from the relay tank 5 and other A belt conveyor 8 that conveys the raw material to the blast furnace 7 receives the sintered ore below the sieve (5 mm or less) of the lower sieve screen B of the vibrating sieve 3 from the chute 9, and returns it to the sintering factory S via the relay tank 11. This is a belt conveyor.

Sintered ore produced at the sintering factory S is supplied to an ore warehouse 2 via a belt conveyor 1. Then, the ore is cut out from the bottom of the ore storage 2 using a cutting device (not shown).
Ripple flow type vibrating sieve 3 (frequency: 840 cpm, vibration mode: circular movement in the vertical direction, number of meshes: vertical interval 600 mm
Upper and lower sieve screens A and 2 upper and lower sieves B, sieve area of each sieve screen is 10 square meters, sieve screen type: Upper sieve screen A is a staggered punched iron plate with oval holes (the long axis of the oval holes is the sieve (inclined at 20 degrees from the longitudinal direction), the lower sieve screen B is a hand-woven net made of round rods with a diameter of 5 mm (sieve mesh: rectangular, the long axis is in the width direction of the sieve), the mesh opening ratio of each sieve: the upper sieve screen A is 45
%, lower sieve mesh B is 35%). Then, each sieved ore is supplied to the relay tank 5 by the belt conveyor 4 via the weighing hopper 10, and the sifted ore of the lower sieve screen B is supplied to the relay tank 11 by the belt conveyor 8 via the chute 9 in the same manner as described above. and return it to the sintering factory S. The ore is cut out from the bottom of the ore storage 2 by a cutting device (not shown) and passed through the upper sieve screen A of the vibrating sieve 3.
The relationship among the sintered ore to be supplied, the mesh size of the upper sieve A and the lower sieve B, the load factor, and the sieve results are shown in Table 1 together with comparative examples.

[Table 1]

[0015] The size of the mesh of the upper sieve A is the same as that of the upper sieve A.
The sintered ore on the sieve of , the sintered ore on the sieve of the lower sieve B, and the mixed sintered ore on the sieves of the upper sieve A and the lower sieve B are sampled at predetermined intervals to determine the weight per unit time or average. The particle size was measured and adjusted by replacing the screen.

As shown in Table 1, when the amount (speed) and average particle size of sintered ore supplied to the upper sieve of the vibrating sieve change, the mesh of the upper sieve is adjusted to increase the load factor of the lower sieve to 40. In Examples 1 to 4, the loading rate of the lower sieve screen was maintained from 40 to 60%.
Compared to the comparative example in which the temperature is not maintained, the amount of powdered sintered ore (5 mm or less) mixed into the blast furnace charging side (the upper side of the sieves of the upper sieve screen and the lower sieve screen) is significantly reduced. This prevents the amount of powdered sintered ore charged into the blast furnace from fluctuating greatly, making it possible to maintain good air permeability of the blast furnace.

[0017]

Effects of the Invention: Even if the particle size of the powder agglomerates supplied to the vibrating sieve changes, the present invention can efficiently sieve the powder agglomerates by simply changing the mesh size of the upper sieve screen. For example, if this method is applied to the sieving of sintered ore and coke to be supplied to a blast furnace, a large amount of sintered ore and coke with a particle size below a specified level will not be charged into the blast furnace, resulting in a stable Blast furnace operations can be maintained, and since sintered ore and coke with a particle size exceeding a specified size are significantly reduced in the sieve, the product yield of sintered ore and coke can be greatly improved. It has excellent effects such as:

[Brief explanation of drawings]

[Figure 1] Diagram showing the relationship between the load factor of the lower sieve screen and the sieve efficiency

[Figure 2
] Diagram showing the relationship between the mesh size of the sieve screen and the average particle size of the sintered ore that passes through the sieve screen (under the sieve)

[Figure 3] Diagram showing the relationship between the mesh size of the sieve screen and the amount of sintered ore passing through the sieve screen (under the sieve)

[Figure 4] Diagram showing the transportation process for transporting sintered ore produced at a sintering factory to a blast furnace

Claims (1)

[Claims] [Claim 1] A method for supplying powdery aggregates of a material to be sieved to the upper sieve screen of a vibrating sieve having two upper and lower sieve screens, and sieving the powdery agglomerates to a predetermined particle size using both the upper and lower sieve screens. According to the average particle size and integrated average particle size on each sieve of the upper and lower sieve screens, or the amount on each sieve, the mesh size of the upper sieve screen is changed and adjusted to increase the loading rate of the lower sieve screen from 40 to 60%. A method for sifting powder aggregates using a vibrating sieve, characterized in that: