JPH02173220A - Method for controlling permeability on pallet in sintering machine - Google Patents

Abstract

PURPOSE:To improve the permeability of sintering raw material by granulating kneaded flake having plastic state from a kneading machine with a granular machine and cascade-controlling granule grain size in accordance with the permeability of the sintering raw material on a pallet. CONSTITUTION:Moisture is added to the sintering raw material to charge this into the kneading machine 5. Then, by using compact medium, exciting-compact kneading is executed with exciting force 3-10g (g: acceleration of gravity). The obtd. kneaded flake having plastic state is charged into an exciting cylindrical type granular machine 6. A cylindrical axis in this granular machine is inclined to the gradient in the range of + or -10 deg. angle and the exciting force is adjusted into the range of 3-5g and and the above raw material is rolling-pelletized and granulated while controlling grain size of mini-pellet. This mini-pellet is blended into the ordinary sintering raw material, and after re-granulating with a mixer, this is supplied into a DL-type sintering machine. Then, the permeability of the sintering raw material on the pallet is measured and compared with the preset permeability. Based on this difference, the grain size of the above mini-pellet is cascade-controlled. By this method, the permeability at the time of sintering is improved saving of power cost in a main exhauster can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for controlling the air permeability of a sintering machine barrel L, and more particularly to a granulation technique that improves the air permeability on a pallet.

[Prior Art] FIG. 4 is an overall flow sheet of a conventional DL type sintering machine. The sintering raw material blending tg11 stores sintering raw materials (fine ore, limestone, coke, quicklime, and return ore), and is fed to a constant feeder 2 provided at the bottom of the blending tank.
After being cut out to a certain length, they are stacked and blended in multiple layers on a belt conveyor 3.

The blended raw materials are mixed and granulated in a drum mixer 4 with the addition of 4 to 5% water. The granules are transported to the ore feed hopper 14 and charged into the pallet I8 of the DL type sintering fi 17 via the lower drum feeder 15 and the ore feed chute 16. After that, the ignition burner 19 is used to pierce the coke powder in the raw material.

Sintering progresses.

In this case, fine iron ore (hereinafter referred to as PF) is also used, in which 60% or more of the particles are less than 60 μm. P.F.
If a large amount of (10% or more based on the main raw material) is used, ventilation of the sintered bed will be inhibited and productivity will decrease. Alternatively, it requires a large amount of binder (quicklime, slaked lime, etc.) to improve ventilation, resulting in a disadvantage that the binder cost increases.

In order to solve the above problems, PF (approximately 60%) and the core raw material (return ore or iron ore 6, approximately 40%) are pre-granulated using a drum mixer or disc beletizer 4, and then sintered. A PF granulation method has been proposed in which PF is mixed with raw materials, charged into a drum mixer 4, and mixed and granulated (Iron and Steel:
vo 1゜71, No, l O (1985) li
'Pelletization of sintering raw materials and its role') In this case, a core raw material is required, so with the same -PF blending ratio, a mixer with a capacity 1.4 times larger is required, and equipment is required. The disadvantage is that it is expensive.

Yet another method is to use normal sintering raw materials (60% fine ore).
) is blended with approximately 40% PF and fed to a disc-type beletizer 4 for mixing and granulation to form pellets of 5 to 10 mm. Thereafter, a method has been proposed in which fine coke is added, the outer periphery of the pellet is sprinkled with exterior coke, and the pellet is transported to the feed hopper 14 and sintered (iron and li4: vol. 7
3゜No, l l (1987) Ii' Basic research on manufacturing conditions and quality evaluation of new agglomerate ore for blast furnaces J
).

A disadvantage of this method is that the green balls have a low apparent density and a low crushing strength, so they are easily broken during the transportation process to the sintered bed, which impedes ventilation of the bed. In addition, the coke diameter of the finished product is large, 8 to 10 mm, and exterior coke is required. Furthermore, if the outer coke does not adhere uniformly to the outer periphery of the pellet, the inside of the ball remains unmelted, and there is a drawback that it is likely to become m- pellet or return ore during the crushing process.

On the other hand, although it is an old technology, the d-co type grinding and kneading granulation method (Japanese Patent Publication No. 43-6256) is known, in which raw materials are ground using a ball mill, rod mill, or other hot grinding and kneading machine. After adjusting the moisture content and mixing, the raw pellets are granulated using a vertical type, cylindrical type, or other type of granulator.

This method accomplishes the conventional wet or dry grinding process and the moisture adjustment mixing process in a single step in a wet state.

This method has a low production volume considering the equipment (and the power consumption is high, so it is currently not economical.

[Problem to be Solved by the Invention 1] In view of the above-mentioned circumstances, the present inventors have attempted to improve quality with high efficiency and high production by mixing a consolidation medium into the sintering raw material and strongly shaking it with circular motion vibration. It is possible to perform excellent vibration compaction kneading, and by using a granulation vibrator to agglomerate the mixture by vibration and rolling, it is possible to efficiently produce strong mini pellets in the desired particle size range. I found out that it is possible.

The present invention is a sintering process that improves air permeability on the pallet in the process of blending the mini-pellets obtained in this way with ordinary sintering raw materials, re-granulating them in a mixer, and then charging them into the sintering machine pallet. It is an object of the present invention to provide a method for controlling air permeability on a binder pallet.

[Step 1 for Solving the Problems] The present invention solves the above-mentioned problems, and employs the following method. That is, water is added to the sintered raw material, the raw material is charged into a consolidation plasticization kneader containing a consolidation medium, and an excitation force of 3 g to tog (g is the acceleration of gravity) is applied to perform vibration consolidation kneading. A process of forming mixed wire flakes in a plasticized state, and charging the kneaded raw material into a vibrating cylindrical granulator, tilting the cylindrical axis of the granulator to a slope within a range of ±10 degrees, or applying an excitation force. After adjusting the raw material to a range of 3 g to 5 g, the raw material is agglomerated by rolling to granulate mini pellets and the particle size is controlled, and the mini pellets are blended with normal sintering raw materials and re-granulated with a mixer. The process consists of the following steps: measuring the air permeability of the sintering raw material on the pallet, comparing the first measurement with the set value, and cascading the particle size of the mini pellets based on the deviation value. [Function 1] The present invention applies an excitation force to the sintering raw material that causes a strong circular motion together with the consolidation medium, so that the consolidation medium rotates in the same direction, and adjacent consolidation media The relative movement of the surfaces in opposite directions imparts consolidation, shearing, transfer, and crushing effects to the particles existing between the consolidation medium, squeezing out the internal moisture of the particles and leveling out the surface moisture.As a result, the particles When a group unites, it transforms into a soldier. In this case, if the excitation force is less than 3 g, the consolidation plasticization will be insufficient and the dry density of the produced pellets will be low, and if it exceeds log, it will be saturated and will be ineffective, so the limit is set to log 6 Next, granulation In the process, when the consolidated and plasticized raw material is transferred by strong vibration, the packing density increases, moisture permeates to the surface, adhesion due to this moisture, and particle size growth occur, making it possible to obtain strong mini pellets. can. If the excitation force in this granulation step is less than 3 g.

The particle size of the mini-bellet is small, and if it exceeds 5 g, the oversize will increase, so the range of the excitation force was set to 3 g to 5 g.

Figure 2 (a) is a graph of the relationship between the granulation degree and the air permeability of Pallet-F when the moisture content of the mixed raw material is taken as a parameter, and Figure 2 (b) is a graph of the relationship between the granulation degree and the air permeability of the mixed raw material when the granulation degree is taken as a parameter. This is a graph showing the relationship between moisture content and air permeability on the pallet. Note that all of these graphs are for the case where the blending ratio of mini pellets is constant. FIG. 2 shows that the air permeability of pallet L can be controlled by the granulation degree or added moisture.

For water addition, it is sufficient to add the difference between the water content of the raw material and the optimum water content ratio for granulation, which is 0 to 2%. That is, when the entire sintered raw material having a wide particle size range is subjected to vibration consolidation, the fI) compatible water ratio is adjusted to 5 to 7% with respect to the moisture content of the raw material of 5 to 6%. In addition, when granulating only PF, PF is 8 to 1
It has a moisture content of 1%, and the optimum moisture content is 9-12%.

The mini pellets produced as described above are blended with ordinary sintering raw materials consisting of lime ore, quicklime, coke and return ore, re-granulated in a mixer, and then charged into a sintering machine pallet. Measure the air permeability of the sintered raw material of pellets h and t, compare the measured value with the set value, and control the particle size of the mini pellets produced by the granulator in a cascade based on the difference value. This allows the ventilation on the pallet to be maintained at its highest level.

[Embodiment 1] FIG. 3 is a system explanatory diagram of an air permeability control device on a sintering machine pallet, in which the present invention can be preferably carried out. Raw material PFi3
and quicklime are made using a consolidation plasticization kneader 5 with a built-in consolidation medium.
After applying an excitation force of 3 g to log and excitation compaction kneading to form plasticized flakes, the kneaded raw material is charged into a granulator 6 consisting of an excitation cylinder, and the granulator 6 consists of an excitation cylinder. The cylindrical axis is inclined at an angle of 10 degrees, or the excitation force is adjusted to a range of 3 g to 5 g, and the raw material is agglomerated by rolling to form solid mini pellets.

Next, the usual sintering raw materials consisting of ore, quicklime, coke and return ore are mixed together with the aforementioned mini pellets in a drum mixer and charged into the sintering machine pallet via the regranulation overbed hopper.

The method of the present invention includes a sintering machine windpock base exhaust air pressure A,
Flow QB and material layer thickness on pallet! - (Measure and enter this manually into the air permeability calculator to calculate air permeability = (B/A)/)
Based on the deviation value between the two, granulation 1 (111
This is a method for controlling the air permeability of the sintering machine pallet L by adjusting the excitation force of step 6 and the water added to the kneader 5 to adjust the particle size of the mini pellets.

The method of controlling the air permeability of the pallet E by adjusting the granulation degree using the water content of the mixed raw material as a parameter, as shown in FIG. 2(a), will be explained in detail with reference to FIG. 1.

(1) When the air permeability is within the normal control range (indicated by the dotted line).

When the air permeability is within the range indicated by the dotted line, the particle size ψ is subjected to feedback control within the range shown.

For example, when 1 air permeability is at point X, the particle size is +Δφ′1i
If it is fitted, the air permeability will be controlled to the set value.

(2) When the air permeability is low outside the range of the dotted line, for example at the 0 point, (D) the particle size φ is controlled to be increased to the upper limit of the control range of the particle size φ.As a result, the air permeability is within the range of the dotted line. Once inside, the control described in (1) above is performed.

■ If the air permeability is lower than the range indicated by the dotted line even after performing the control described in (1). For example, if the air permeability is 7E at 0 point, find the moisture Δm corresponding to the air permeability difference ΔP with the currently set moisture characteristics.
Adjust the amount of water added +5m, and change the particle size φ to particle size φ
control to bring it back within range. As a result, if the air permeability falls within the range indicated by the dotted line, the above-mentioned control (1) is performed.

Note that Δm can be obtained from the diagram as follows. Namely.

ΔP ” P , o − P s, Δm=8P/ΔP(
3) When the air permeability is high outside the range of the dotted line, for example when it is at the 0 point, (1) The particle size φ is controlled to be reduced to the lower limit of the control range of the particle size φ. As a result, if the air permeability falls within the dotted line range,
- The above-mentioned system (1) (carry out wholesale).

■ If the air permeability is higher than the range indicated by the dotted line even after performing the control described in (1), for example, if it is at point Δ, the air permeability difference ΔP with the currently set moisture characteristics, and the moisture Δml that is higher than 1. is determined, and the amount of water added is adjusted by -Δm1, and the particle size φ is controlled to return within the control range of the particle size ψ. Result 5
If the air permeability falls within the range indicated by the dotted line, the above-mentioned control (1) is performed.

Note that Δm is obtained from the diagram as follows in the same manner as Δm described above. That is, ΔP,=P,, -P,,.

Δm+=Δp, , /ΔP Here, the subscript 9, to, ttiia indicates the water percentage.

By adjusting the particle size of the mini pellets as described above, the air permeability on the pallet can be controlled.

〔Effect of the invention] The present invention has the following extremely excellent effects.

(The degree of packing of powder particles in the mini pellets becomes denser, the strength of the raw mini pellets, dried mini pellets and fired mini pellets is improved, the air permeability during sintering is improved, and the power cost of the main exhaust fan is reduced. Savings are possible.

(2) Since the air permeability during sintering is improved, it becomes possible to mix 5% PF, and it is possible to reduce the raw material cost.

■It is possible to reduce the ratio of defective particle sizes in the mini pellets charged into the sintering machine, and the rate of return ore generation can be reduced, making it possible to improve operational efficiency.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of the control method of the present invention, Figure 2 (a) is a graph of the relationship between the granulation degree and the air permeability on the pallet when the moisture content of the mixed raw material is used as a parameter, and Figure 2 (b) is a graph of the relationship between the moisture content of the mixed raw material and the air permeability on the pallet when the granulation degree is taken as a parameter, FIG. 3 is a system diagram of a control device that preferably implements the present invention, and FIG. This is the entire flow sheet of the sintering process. 5... Mixer 6... Granulator φ... - Granulation degree P... Air permeability

Claims (1)

[Claims] 1. Moisture is added to the sintering raw material, and the raw material is charged into a consolidation plasticization kneader containing a consolidation medium, and an excitation force of 3 g to 10 g (
g is the acceleration of gravity) to form kneaded flakes in a plasticized state through vibration compaction kneading, and charging the kneaded raw material into a vibrating cylindrical granulator, and inserting the cylindrical shaft of the granulator into a step of granulating mini-pellets and controlling the particle size by tilting the raw material to a slope in the range of ±10 degrees or adjusting the excitation force to a range of 3 g to 5 g, and then agglomerating the raw material by rolling, The process consists of mixing the mini pellets with regular sintering raw materials, re-granulating them in a mixer, and then feeding them to the DL sintering machine.Measuring the air permeability of the sintering raw materials on the pallet, and calculating the measured value. A method for controlling air permeability on a sintering machine pallet, characterized in that the particle size of the mini pellets is controlled in a cascade manner based on the deviation value compared with a set value.