JPH0483826A - Method for pretreating pulverized sintering raw material - Google Patents

Abstract

PURPOSE:To improve the kneading performance and kneading treatment capacity of a kneading machine by specifying the ratio of the cylindrical inside diameter of an exciting and kneading machine to the diameter of a compacting medium, the filling rate of the compacting medium and the speed of rotations in an exciting motor. CONSTITUTION:The ratio of the cylindrical inside diameter of an exciting and kneading machine to the diameter of a compacting medium is regulated to >=15, and the filling rate of the compacting medium in the exciting and kneading machining is regulated to 13 to 50%. Then, a pulverized sintering raw material is fed to the above exciting and kneading machine and is kneaded. At this time, for executing the kneading under the operating condition of 3 to 10g vibrating acceleration in the kneading machine, the speed of rotations in an exciting motor of the exciting machine, e.g. in a vibro motor is controlled. At the time of kneading the pulverized sintering raw material under the above-mentioned conditions, the moisture content in the kneaded material is made uniform, and its pelletizing properties in the following pelletizing stage is remarkably improved. Moreover, by the compacting effect, the ball strength of the kneaded material is improved, and furthermore, the effects of accelerating the circulating speed of a rod and the transferring speed of the raw material, improvement in treating capacity or the like can be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for pre-processing fine sintered raw materials, and more specifically, a method for pre-processing sintered raw materials such as iron ore to a DL type sintering machine to produce sintered ore. The present invention relates to a method for pre-processing fine powder sintering raw materials used during firing.

Conventional technology Figure 8 shows a total of 70 sheets of a conventional DL type sintering machine, and a sintering raw material mixing tank 1 contains sintering raw materials (fine ore, limestone, coke powder, quicklime). After the constant feeder 2 installed at the bottom of the blending tank cuts out a fixed amount of the raw ore, the raw ore is transferred to the belt conveyor 3. i pile is mixed. The mixed raw materials are mixed and granulated in a drum mixer 4 by adding 4 to 5% water. The granules are transported to the ore feed hopper 5, and charged into the pallet 8 of the DL type sintering machine 10 via the lower drum feeder 6 and ore feed chute 7. Thereafter, the ignition burner 9 ignites the coke powder in the raw material, and sintering progresses.

In this case, fine iron ore (hereinafter referred to as PF) in which 60% or more of the particles are 60 μm unlayered is also used. 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. Another drawback is that a large amount of binder (quicklime, slaked lime) is required to improve ventilation, and the cost of the binder 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, and then sintered. A nuclear granulation method for PF has been proposed in which PF is mixed with raw materials and charged into a drum-type mixer or disk-type beletizer, and mixed and granulated (Tetsu to Hagane: vo 1.71.) klO(1
985) "Pelletization of sintering raw materials and its role").

In this case, since a core raw material is required, the same -PF
The mixing ratio requires a mixer with a capacity 1.4 times larger, which has the drawback of increasing equipment costs.

Yet another method is to use normal sintering raw materials (60% fine ore).
) is blended with about 40% PF and fed to a disk-type beretizer for mixing and granulation to make pellets of 5 to 10M.

A method has been proposed in which pulverized coke is then added, and the outer periphery of the pellet is coated with coke, and the S-coated pellet is transported to an ore feed hopper and sintered (Iron and Steel: vo 1.73,
~11 (1987) rBasic research on manufacturing conditions and quality evaluation of new Kaisei ore for blast furnaces'').

The disadvantages of this method are that the green balls have a low apparent density and a low crushing strength, and are easily broken during the transportation process to the sintered bed, which impedes ventilation of the bed. Moreover, the average particle size of the finished product is 8 to 101w111, which requires packaged coke.

Furthermore, if the exterior coke does not adhere uniformly to the outer periphery of the pellet, the inside of the ball will not be melted and the pellet will become a single pellet in the crushing process, but there is a disadvantage that it is likely to become return ore.

On the other hand, although it is an old technology, the hot grinding and kneading granulation method (
(Japanese Patent Publication No. 43-6256) is known, and after grinding, moisture adjustment, and cross-mixing of raw materials in a ball mill, rod mill, or other hot grinding and kneading machine, it is made into vertical, cylindrical, or other granules. A machine is used to granulate raw pellets.

This method accomplishes the conventional wet or dry grinding process and the * minute adjustment mixing process in a single culm in a wet state.

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

Therefore, as a method for solving the above problem, the present inventors first applied circular vibration to a horizontal cylinder filled with rods, put fine powder sintering raw material into the cylinder, added an appropriate amount of water, and kneaded it. We proposed a method for manufacturing mini pellets by forming flaky raw materials and then feeding them into a horizontal cylinder that is subjected to circular vibration. This method allows mini pellets to be obtained continuously and easily, and is basically an excellent granulation technique. However, in this method, if the crosstalk is not sufficient, there is a problem that the strength of the obtained mini pellets is insufficient, or particles of a predetermined size cannot be obtained during granulation, resulting in collapse. One possible solution to this problem is to increase the residence time and increase the crosstalk capability, but in this case, a new problem arises in that the processing capacity is significantly increased and the production efficiency is reduced.

Problems to be Solved by the Invention The present invention aims to solve the above-mentioned problems, and specifically, it aims to solve the above-mentioned problems. When granulating the fine powder sintered raw material using a machine and a granulator that applies circular or horizontal vibration to the fine powder sintered raw material discharged from this kneader and rolls and agglomerates the fine powder sintered raw material,
The purpose of this paper is to propose a method for pre-processing fine powder sintered raw materials that can improve the crosstalk performance and crosstalk handling capacity of a kneader.

As a means to solve the problem, the present invention provides a vibrating kneader including a cylindrical kneader containing a consolidation medium and a vibrator for vibrating and rolling the consolidation medium; When granulating fine powder sintered raw material using a vibratory granulator that applies circular vibration or horizontal rocking vibration to the raw material discharged from a vibratory kneader to form rolling agglomerates, The ratio of the cylindrical inner diameter of the kneader to the diameter of the consolidation medium is 15 or more, and
Fill the consolidation medium to the internal volume of the vibrating kneader from 13 to 5.
0%, and the operating conditions of the vibrating kneader are vibration acceleration of 3 to 10.
The present invention is characterized in that the rotational speed of the vibration motor of the vibration exciter is controlled so that the rotation speed of the vibration motor of the vibration exciter becomes

Hereinafter, the structure and operation of the means of the present invention will be explained in detail with reference to the drawings.

Fig. 1 is a partially cutaway perspective view illustrating the vibrating kneader used in carrying out the present invention, and Fig. 2 shows the AZ20a poll space factor and Al2O3 ball movement in one embodiment of the present invention. It is a graph showing the relationship with speed, and FIG. 3(a),
(b), (C), (d) and (e) are the discharge status of each raw material when the excitation force is kept constant and the rod diameter and number of rods are varied in the excitation kneader of the present invention. FIG. 4 is a graph showing the relationship between rod filling rate and moisture variation, and FIG. (a) shows the relationship between the excitation acceleration and the apparent density, (b) shows the relationship between the excitation acceleration and the crushing strength, and FIG. 6 is a graph showing the relationship between the excitation acceleration and the crushing strength. FIG. 7 is a graph showing the relationship between the vibration acceleration and the total vibration width of the vibrating kneader, FIG. 7 is an explanatory diagram of the relationship between the diameter of the granulator and granulation performance, and FIG.
The figure shows the overall flowchart of a conventional DL type sintering machine.

Reference numeral 11 is a frequency variable device, 12 is a pieromotor, 1
3 is the drum body,] 4 is the timing belt, 15 is the shaft,
16 is a bearing, 17 is a spring, 18 is a pulley, and 19 is a rod.

First, as shown in FIG. 1, the vibrating kneader according to the present invention is
It consists of a kneader with an attached vibrator that has a vibration function. The mixer is equipped with a supply port and a discharge port for fine powder sintering raw material supported by a spring 17 on a support base, and is composed of a drum body 13 in which a predetermined amount of rods 19 are filled. A frequency variable device 11, a vibromotor 12, and a pulley 18 are arranged on a shaft 15 via a bearing 16, a timing belt 14 is attached to this pulley 18, and the frequency of the vibromotor 12 is varied by a peripheral fluid frequency variable device. It consists of things that are configured to do this.

This vibrator is designed so that the number of fluids around the vibromotor 120 can be varied by the signal from the fluid number variable device 11, and by changing the rotational speed of the timing belt 14, the vibration vibration can be adjusted. It is possible to change the vibration acceleration, amplitude, etc. of one machine.

In order to sufficiently mix the wires using the vibrating kneader configured as described above and obtain a good mini-bere I, it is necessary to set the ratio of the cylindrical inner diameter of the vibrating kneader to the diameter of the consolidation medium to 15 or more, and to The filling rate of the consolidation medium in the shaking kneader is set to 13 to 50%, and the fine powder sintered raw material is supplied to this shaking kneader and kneaded.

In this case, in order to perform kneading under an operating condition where the vibration acceleration of the mixer is 3 to 10 (), the rotational speed of the vibration motor of the shaker, such as a vibromotor, may be controlled.

When fine powder sintered raw stone is kneaded under such conditions, the moisture content of the mixed material becomes uniform, and the granulation properties in the next granulation process are greatly improved.In addition, the ball strength is improved due to the compaction effect of the mixed material. In addition, the circulation speed of the rod and the transfer speed of the raw material become faster, and effects such as improved processing capacity can be obtained.

The reason for the above limitation will be further explained below.

Figure 2 shows that Al2O:1 balls are inserted into the drum body of the vibrating kneader of the present invention instead of rods, and the vibration amplitude, frequency, pore space, etc. are varied as shown in Table 1. This is a graph showing an example of the experimental results of the change in ball movement speed when changing the ball speed.As is clear from Figure 2,
AZ20: +The higher the space factor of the balls and the larger the amplitude, the higher the ball transfer speed becomes. - In the first expression, when increasing the processing capacity of the vibration kneading example, the vibration frequency must be increased. It can be said that increasing the amplitude is more preferable than increasing the amplitude because the moving speed of the charged material increases.

In addition, in Fig. 3 (al, (1)), (C), (d), and (e), the excitation force is constant in the excitation kneading machine, respectively.
The raw material discharge situation is shown when the filling rate is changed every second by changing the opening/rad diameter and the number of rods. As shown in Figure 3 (a), the rod diameter is 1001111'O and the number of rods is 2.
In the region where the filling b14 ratio is 20% with 0 rods, the raw material is not meshed between the rods, a so-called short bath occurs in the flow of the raw material, and it can be seen that the raw material is discharged without being sufficiently kneaded. Next, as shown in Figures 3(b) and (C), the rod diameter was reduced to 90 gwn, and the filling rate was 9.7% when the number of rods was 12 and 20, respectively. It was 16.2%. However, no improvement in short bathing was observed even when the filling rate was changed.

Next, as shown in Figure 3(d), a decrease in the number of short bass was observed when using the 75-kaku small-diameter rod. Further, as shown in FIG. 3(e), when the rod diameter was reduced to 7Qmm and the filling rate was increased to 23%, the short bath was eliminated and the raw material was discharged uniformly. In this state, it is considered that the charged raw materials are uniformly subjected to the crosstalk action, and at this time, the drum diameter'rod diameter>15. However, when ordinary steel (SS material) is used for the rod, if the rod diameter is set to 501111 or less, the rod becomes easy to bend and the crosstalk effect is significantly reduced. Therefore, the upper limit of the drum diameter 5·' rod diameter is preferably 25, and in order to make it larger than this, it is necessary to use a material with less bending, such as special steel, for the rod.

On the other hand, Figure 4 shows the relationship between the moisture content variation after the raw materials are kneaded and the rod filling rate. Taking Kudremukh ore as an example, the variation decreases from 13% to 16%.
There is a stagnation in the decrease, and the variation saturates to a constant value at 20 to 23%. Increasing the filling rate increases the size of the vibrator itself. Therefore, the upper limit of the filling rate is practically 50.

Next, the vibration mixture Il! The relationship between the vibration acceleration and the apparent density and crushing strength of the granulated material when the vibration acceleration of the machine was changed is shown in the graphs of FIGS. 5(a) and 5(b), respectively. Moreover, the apparent density and crushing strength of the granulated product of the comparative example were also lower than those shown in FIGS. 5<8) and (b).

The bulk density of the raw material before granulation is 2.5 g, '113, and the apparent dry density of the granulated product granulated with a disc beletizer is 3.
．． It was 1. On the other hand, in the example, the apparent density was very high, ranging from 3.6 to 4.4, depending on the vibration acceleration.

In addition, granules granulated with a disc beletizer (particle size 5M
The crushing strength of the wet ball was about 70Q2, whereas in the example, the crushing strength was extremely strong at about 130 to 150g depending on the vibration acceleration.

Figures 5 (a) and (b) show that when the vibration acceleration of the vibration kneader is 3Q, the effect of consolidation granulation is small, and when it exceeds 10 (), it is saturated; It turns out that the appropriate range is 3-100.

Therefore, in the crosstalk process, the vibration acceleration is in the range of 3 to 10Q, the drum diameter is 7, the rod diameter is 15 to 25, the filling rate is 13 to 50%, and especially 16 to 50%.
is the most preferable range.

In addition, as shown in Fig. 6, as a result of investigating the relationship between vibration acceleration α(Q) and total amplitude S (1+11), it was found that in order to control vibration acceleration α3 to 10g, the total amplitude S must be increased to 12 to 14 kg. In this case, the rotation speed of the vibration motor of the vibration exciter is 600rl)m, 3q is 90Orpm, and 5C1i13
Therefore, the vibration acceleration can be controlled in accordance with the rotational speed e+m.

Next, a vibrating granulator according to the present invention will be explained.

The fine powder sintered raw material mixed in the above-mentioned vibrating kneader is granulated by a vibrating granulator.
Although the above vibration acceleration is applied to granulate, it is necessary to consider the following factors as factors governing the granulation effect.

In other words, as shown in Figure 6, there is a correlation between the diameter of the granulator and the granulation performance, and when comparing the case where the granulator drum has a small diameter and the case where the granulator drum has a large diameter, the rolling speed, drum shell and Regarding the contact time, the smaller the diameter, the higher the rolling speed, the shorter the contact time with the shell, and the better the granulation performance. That is,
If the contact period between the shell and the raw material is long, too much water in the raw material will come out to the surface area, resulting in a cake-like shape and the granulation size will become excessive.
Further, as this progresses, the amount of cake-like raw material increases and the granulation effect disappears.

V, ■...Rolling speed D, t...Contact time between raw material and shell N, n...
・・・・Number of rolling times However, if the upper case letter means a large diameter drum (diameter 944 m) and the lower case letter means a small diameter tram (diameter 250 m), then V>V, and when t << , too much water from the lower layer comes out and the It becomes like this.

When n〉N, the exchange rate of the raw materials in the middle part and the peripheral part decreases, and the variation in particle size increases.

Furthermore, the variation in particle size that governs granulation performance becomes smaller and better as the number of rolling vibrations of the raw material increases, but the number of rolling vibrations in large diameter drums is lower than in small diameter drums, leading to an increase in variation in particle size. It has been found. The results of testing this for each drum diameter are shown below.

The throughput of the granulator is expressed by the following formula.

Processing @ −−□XQ2Xφ×γxypxn...(
a Here, D: Drum diameter α Nidrough angle φ; Raw material space β; Raw material repose angle γ; Raw material Takada degree μ: H coefficient Vp: Raw material movement speed N: Vibration frequency n Number of Nidrums S: Amplitude φ, If γ and Vp are constant, the process becomes D2×n (C1).

However, as mentioned above, a problem occurs when the drum diameter of the 01 type is increased.
In the case of 0 mmφ and 300 anφ, the granulation property was good, in the case of 340+imφ, cake-like materials started to be mixed, and in the case of 450 wφ, cake-like raw materials increased and granulation was difficult. Therefore, the drum diameter of the granulator needs to be 45011IIlφ,
The diameter is preferably 340Hφ or less. On the other hand, from the perspective of the granulation throughput, reducing the diameter of the drum is the process Im, but in order to produce even more for the sintering machine, it is sufficient to combine a plurality of small diameter drums and granulate them at the same time.

EXAMPLE Using a W4-built vibrating mixed Hv1 shown in Figure 1, the processing capacity was 1.
20t'h, drum diameter 1000n+mφ, vibration weight 1
Under the following operating conditions, water was added to the fine powder sintered raw material consisting of PF to make the moisture content 10%.

(1) Rod length: 5Qmmφ 2) Loft filling''*: 25% 3) Vibration motor rotation speed: (variable) 4) Amplitude 2 12-14mm 5) Vibration acceleration: 3-10CI 6) Vibration crab 30-60t As a result, the moisture content of the mixed material was uniform, improving the ball strength, and the rod circulation speed increased the raw material transfer speed, improving throughput.

Next, this mixed material was granulated using a vibrating granulator with a drum diameter of 300 mm, and strong mini pellets with a particle size of 2 to 5 mm were obtained.

ξEffect of the invention 2 As explained in detail above, the present invention provides a vibrating kneader including a cylindrical kneader containing a consolidation medium and a vibrator for vibrating and rolling the consolidation medium; When granulating fine powder sintered raw material using a vibration granulator that applies circular vibration or horizontal rocking vibration to the raw material discharged from the kneader and rolls it into agglomerates,
The ratio of the cylindrical inner diameter of the vibrating kneader to the diameter of the consolidation medium is 15g.
, above, the filling ratio of the consolidation medium to the internal volume of the vibratory mixing sIR is 13 to 50%, and the vibration motor rotation of the vibrator is set such that the operating conditions of the vibrating kneader are vibration acceleration of 3 to 10Q. It is characterized by controlling the number.

According to the processing method according to the present invention, the following effects can be obtained.

(1) The moisture content of the mixed material becomes uniform, improving granulation performance in the next granulation process.

(2) Due to the compaction effect of the kneaded material, the wire crossing performance is improved and the ball strength is improved.

(3) The circulation speed of the rod and the transfer speed of the raw material are increased, and the throughput is improved.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway perspective view illustrating an excitation kneader used in carrying out the present invention, and Fig. 2 shows the A42Ch ball space factor and AZ2C): + ball of one embodiment of the present invention. Graph showing the relationship with movement speed, Figure 3 (a), (b)
, (C), (d) and (e) are explanatory diagrams of the discharge status of each raw material when the excitation force is kept constant and the rod diameter and number of rods are changed in the vibration 88 machine of the present invention, respectively. Figure 4 is a graph showing the relationship between rod filling rate and moisture variation.
FIGS. 5(a) and 5(b) each show the state when the vibration acceleration of the vibration kneading method of the present invention is changed, and (a)
) shows the relationship between the vibration acceleration and the apparent density, (b) shows the relationship between the vibration acceleration and the crushing strength, and Figure 6 shows the relationship between the vibration acceleration and the total density of the vibration kneader of the present invention. FIG. 7 is a graph showing the relationship between vibration width, FIG. 7 is an explanatory diagram of the relationship between the diameter of the granulator and granulation performance, and FIG. 8 is an overall flow sheet of a conventional DL type sintering machine. Symbol 11... Circumferential fluid number variable device 12... Vibro motor 13... Drum body 14... Timing belt 15... Shaft 16. ... Bearing 17 ... Spring 18 ... Pulley 19 ... Rod Fig. 2

Claims (1)

[Claims] 1) A vibratory kneader equipped with a cylindrical kneader containing a consolidation medium and a vibrator that vibrates and rolls the consolidation medium, and a vibratory kneader that applies circular vibration or horizontal vibration to the raw material discharged from this vibratory kneader. When granulating fine powder sintered raw materials using a vibratory granulator that applies dynamic vibration to roll and agglomerate, the ratio of the cylindrical inner diameter of the vibratory kneader to the diameter of the consolidation medium is determined. 15 or more, and the filling ratio of the consolidation medium to the internal volume of the vibrating kneader is 13 to 5.
0%, and the operating conditions of the vibrating kneader are vibration acceleration of 3~
A method for pre-processing a fine powder sintering raw material, characterized in that the rotational speed of the vibration motor of the vibration exciter is controlled so that the vibration becomes 10 g.