JP2000237614A - Crushing/classification method and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the grain size distribution to be optionally changed by arranging a grain size distribution adjusting means between the upper end level of a crushing roller in a crushing chamber and the lower end face level directly below the lower part of a classifying chamber. SOLUTION: The crusher/classifier comprises and upright roller mill crushing chamber 3 provided at the lower part of an external airtight casing 1 and an air classifying chamber 5 provided at the upper part. Further, the crushing chamber 3 has plural crushing rollers 8 arranged on a crushing table 7 equipped with a dam ring. When a primary air current FA for conveying/classification located between the upper end level of the crushing roller 8 and the end face level directly below the lower part of the classifying chamber 5 is made to gyrate and thereby a finely shredded raw material BM is made to ascend, a secondary air current SA for conveying/ classification is allowed to be confluent with the primary air current FA from the tangential direction near a secondary cir current introduction part 60 to increase the air flow. Thus the air currents FA, SA are made to reach an air classifier 11 through a guide vane 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for pulverizing limestone, cement raw materials, cement clinker, ore, silica stone, etc., with a vertical roller mill, and then classifying them with an air classifier.

[0002]

2. Description of the Related Art A pulverizing and classifying apparatus for limestone, cement raw material, cement clinker, ore, silica stone, etc. (hereinafter referred to as pulverized raw material) comprises a vertical roller mill pulverizing chamber provided at the lower part of an outer closed casing, An air classifying chamber provided at the top of the container, a nozzle for supplying a primary air flow for conveying classification into the outer closed casing to form a swirling flow from the pulverizing chamber toward the classifying chamber, and a pulverized raw material in the pulverizing chamber. Feeding means for supplying

[0003] In this apparatus, the pulverized raw material is supplied to a vertical roller mill pulverizing chamber via a feeding means and pulverized, and the pulverized raw material is separated from the pulverizing chamber formed in the outer closed casing by air classification. It rises on the transport swirl flow toward the chamber. The raw material conveyed to the air classification chamber is classified into coarse powder (fine powder) and fine powder by an air classifier, and the coarse powder (fine powder) is returned to the pulverization chamber and re-pulverized. The fine powder is separated from the air through a bag filter, and then recovered as a product.

[0004]

In the case of pulverizing and classifying pulverized raw materials, the requirements for the size of the particle size and the width of the particle size distribution are different depending on the product to be manufactured. Therefore, in order to obtain a product particle size distribution that meets the above requirements, in the conventional example,
A control method combining the following (1) to (3), or (1) to
A control method combining (4) is used.

(1) To change the inclination angle of the guide vanes of the air classifier. (2) Changing the rotation speed of the rotor blade of the air classifier. (3) Changing the classification air volume, that is, changing the primary airflow of the classification for conveyance guided from the entrance of the crusher. (4) Changing the distance between the crushing chamber and the classification chamber, that is, changing the height of the classification chamber.

In the control method (4), casings having different heights, that is, a high side casing for classifying fine powder or a coarse powder are classified and adjusted between the pulverizing chamber and the classifying chamber. The low-side casing, for mounting. Therefore, this method is troublesome and goes against labor saving and improvement of the operation rate. Therefore, in practice, the above methods (1) to (3) are mainly used at the same time, and various particle size distributions are obtained by combining three manipulated variables.

[0007] Further, among the pulverized products pulverized in the pulverizing chamber, in particular, lump such as lump and flake lump are operated under the pulverization condition such that they are not dropped and discharged by the nozzle from the viewpoint of pulverization efficiency. Have been. Therefore, if flakes are generated in the pulverization of the pulverization area, the system cannot be further pulverized.

[0008]

The particle size distribution of a powdery material for a functional material or the like in recent years has been desired to have various distributions as compared with the conventional particle size distribution. In other words, there is a demand for a powdery or granular material having a sharp or broad distribution and further less coarse particles falling into the powder, or a powdery or granular material having the same specific surface area but having a significantly different particle size distribution width. Further, from the viewpoint of labor saving, energy saving, and improvement of the operation rate, easy operation is required for controlling the product particle size distribution. However, in the conventional example, it was a fact that this demand could not be met.

In the conventional pulverizing region, the cohesive force of the fine powder becomes very strong, and agglomerates (flakes) are formed in the pulverizing chamber. Therefore, the flakes fall against the primary air flow for the transport classification at the same time as the remarkable decrease in the fine grinding efficiency,
Since it is discharged outside the pulverizing chamber, not only the continuous stable operation of the pulverizer cannot be performed, but further pulverization cannot be performed, and the pulverization limit is reached.

In view of the above circumstances, it is an object of the present invention to make it possible to arbitrarily change the particle size distribution and to make the change simple and easy. Another object is to improve the grinding efficiency in the fine grinding region.

[0011]

According to the present invention, a vertical roller mill crushing chamber provided at a lower portion of an outer closed casing is provided.
An air classification chamber provided at an upper part of the outer closed casing, a nozzle for introducing a primary air flow for transfer classification into the outer closed casing to form a swirling flow from the crushing chamber to the classification chamber, A feeding means for supplying a raw material to the chamber; a grinding / classifying apparatus; provided between an upper end level of a grinding roller of the grinding chamber and a lower lower end surface level of the classifying chamber; It is characterized in that a particle size distribution adjusting means for introducing a secondary air flow for transport classification into the swirling flow is provided.

According to the present invention, there is provided a vertical roller mill pulverizing chamber provided at a lower portion of an outer sealed casing, an air classifying chamber provided at an upper portion of the outer sealed casing, and a primary air flow for transport classification in the outer sealed casing. A pulverizing and classifying apparatus comprising: a nozzle for introducing and forming a swirling flow from the pulverizing chamber to the classifying chamber; and feeding means for supplying a pulverized raw material to the pulverizing chamber; And a crushing / circulating / conveying means for crushing the flakes discharged from the feeding means and feeding the flakes to the feeding means.

According to the present invention, there is provided a vertical roller mill crushing chamber provided at a lower portion of an outer sealed casing, an air classifying chamber provided at an upper portion of the outer sealed casing, and a primary air flow for transport classification in the outer sealed casing. A pulverizing and classifying apparatus comprising: a nozzle for introducing and forming a swirling flow from the pulverizing chamber to the classifying chamber; and feeding means for supplying a pulverized raw material to the pulverizing chamber; A particle size distribution adjusting means disposed between the upper end level of the classifying chamber and the lower right lower end surface of the classifying chamber, and for introducing a secondary air current for conveying classification into the conveying swirl flow; and And a crushing / circulating / conveying means for crushing the discharged flakes and sending the flakes to the sending means.

According to the present invention, there is provided a step of supplying a pulverized raw material to a vertical roller mill pulverizing chamber provided at a lower portion of an outer closed casing, and pulverizing the pulverized raw material, forming the pulverized raw material in the outer closed casing, A pulverization classification method comprising: a step of transporting the raw material conveyed to the air classification chamber by a transport swirling flow from the pulverization chamber to the air classification chamber; and a step of air classifying the raw material transported to the air classification chamber; A secondary air stream for transport classification is introduced from a tangential direction into the transport swirling flow located between the upper end level of the pulverizing roller and the lower right lower end surface level of the classification chamber.

According to the present invention, there is provided a step of supplying a pulverized raw material to a vertical roller mill pulverizing chamber provided at a lower portion of an outer closed casing, and pulverizing the pulverized raw material. A pulverizing and classification method comprising: a step of transporting the raw material transported by a transport swirl flow from a chamber to an air classification chamber; and a step of air-classifying the raw material transported to the air classification chamber; After the flakes discharged from the chamber are crushed, the flakes are returned to the crushing chamber via feeding means for supplying crushed raw materials.

According to the present invention, there is provided a step of supplying a pulverized raw material to a vertical roller mill pulverizing chamber provided at a lower part of an outer closed casing and pulverizing the pulverized raw material, forming the pulverized raw material in the outer closed casing, A pulverization classification method comprising: a step of transporting the raw material conveyed to the air classification chamber by a transport swirling flow from the pulverization chamber to the air classification chamber; and a step of air classifying the raw material transported to the air classification chamber; In the transport swirling flow located between the upper end level of the crushing roller and the lower lower end surface level of the classification chamber, a secondary air flow for transport classification is introduced from a tangential direction, and discharged from the vertical roller mill crushing chamber. The flakes are returned to the pulverizing chamber via a feeding means for supplying a pulverized raw material.

According to the present invention, there is provided a step of supplying a pulverized raw material to a vertical roller mill pulverizing chamber provided at a lower portion of an outer closed casing, and pulverizing the pulverized raw material, forming the pulverized raw material in the outer closed casing, and A pulverizing and classifying method comprising: a step of transporting the raw material conveyed to the air classifying chamber by transporting the raw material conveyed to the air classifying chamber from the pulverizing chamber; and a step of air classifying the raw material conveyed to the air classifying chamber; In the transport swirl flow located between the upper end level of the pulverizing roller and the lower right lower end surface level of the classification chamber, a secondary air flow for transport classification is introduced from a tangential direction and discharged from the vertical roller mill pulverization chamber. After the flakes are crushed, the flakes are returned to the crushing chamber via a feeding means for supplying a crushed raw material.

According to the present invention, there is provided a step of supplying a pulverized raw material to a vertical roller mill pulverizing chamber provided at a lower portion of an outer closed casing, and pulverizing the pulverized raw material, forming the pulverized raw material in the outer closed casing, and A pulverizing and classifying method comprising: a step of transporting the raw material conveyed to the air classifying chamber by transporting the raw material conveyed to the air classifying chamber from the pulverizing chamber; and a step of air classifying the raw material conveyed to the air classifying chamber; In the transport swirl flow located between the upper end level of the pulverizing roller and the lower right lower end surface level of the classification chamber, a secondary air flow for transport classification is introduced from a tangential direction and discharged from the vertical roller mill pulverization chamber. After crushing the flakes, the crushed material is supplied to the introduction section of the secondary airflow for transport classification.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The inventor of the present invention tangentially supplies a secondary airflow for transport classification to a primary airflow (swirl flow) for transport classification rising from a pulverizing chamber to a classification chamber in an outer closed casing. Various experiments were conducted on the assumption that the particle size distribution of the crushed product could be changed by changing the flow ratio of the two airflows.

As a result, when the secondary air flow is introduced from between the upper end surface level of the pulverizing roller in the pulverizing chamber and the lower right lower end surface level of the classifying chamber, the particle size distribution can be significantly changed by changing the flow ratio of the two air flows. Knew.

The flakes generated in the pulverizing chamber are discharged from the pulverizing chamber and returned to the pulverizing chamber via the feeding means to be re-pulverized, or the flakes discharged from the pulverizing chamber are pulverized by the pulverizing means. Later, it was found that the pulverization efficiency was improved by returning to the pulverization chamber via the feeding means.

The present inventors have completed the present invention based on the above findings.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. In the pulverizing classifier, a vertical roller mill pulverizing chamber 3 is provided at a lower portion of the outer closed casing 1, and an air classifying chamber 5 is provided at an upper portion thereof.

In the crushing chamber 3, a crushing table 7 having a dam ring 6, a plurality of crushing rollers 8 disposed on the crushing table 7, an outer peripheral portion of the table 7 and the casing 1 are formed. And a nozzle 10 provided therebetween.

The classifying chamber 5 is provided with an air classifier 11. The air classifier 11 includes a plurality of guide vanes 1
3 and a plurality of rotor blades 20.

The inner peripheral end of each guide vane 13 is a pin 1
5 is fixed to the lower end. The pin 15 is rotatably supported by the ceiling 14 of the outer closed casing 1.
Each pin 15 penetrates through the ceiling portion 14, and one end of an arm 16 is attached to an upper end thereof. The other end of the arm 16 is connected to a long hole formed in the rotatable connecting ring 17 at a circumferentially equal position by a pin 18. By rotating the connecting pin 18, all the guide vanes 13 can be tilted at the same tilt angle.

The rotor blade 20 is disposed concentrically with the inner hopper 12, and a classification gap 22 is formed between the rotor blade 20 and the inner hopper 12. The rotor blade 20 is rotatably operated by remote control via a motor, a speed reducer, and a vertical axis drive (not shown).

A fine powder outlet 30 is provided at an upper portion of the inner hopper 12, and a coarse powder outlet 40 is provided at a lower portion thereof. The fine powder outlet 30 communicates with a blower 34 via a bag filter 32. Also, coarse powder outlet 40
Is a horizontal discharge facility 42 penetrating the outer sealed casing 1
Is in communication with

The outlet of the horizontal discharge equipment 42 is connected to the calibration device 4
3 is connected to the inlet 43a of the
b is connected to the screw conveyor 51 via the circulation circuit 50.

A mill feed bin 53 and a rotary feeder 54 are connected to the screw conveyor 51, and an outlet 51a of the mill feed bin 53 is connected to a screw conveyor 55 which is a raw material feeding means. This screw conveyor 5
The outlet 55 a of 5 faces the center of the crushing table 7. In addition, as a supply means, the screw conveyor 55
In addition, a chute or a belt conveyor can be used. Further, the screw conveyor 51 may be omitted, and the mill feeder bin 53, the rotary feeder 54, and the like may be connected to the screw conveyor 55.

The outer airtight casing 1 is provided with a secondary airflow introducing section 60. As shown in FIG. 3, the introduction section 60 is composed of four introduction pipes 60P oriented in a tangential direction, and the number of the introduction pipes 60P is appropriately selected as needed. The introduction portion 60 is provided at a position facing the lower portion of the coarse powder outlet 40 of the inner hopper 12,
It is not necessarily limited to this position.

According to an experiment, in order to greatly change the particle size distribution width, the level between the upper end level LL of the pulverizing roller 8 of the pulverizing chamber 3 and the lower end level HL of the lower part (guide vane 13) of the classifying chamber 5 is set. It has been found necessary to dispose the secondary airflow introduction section 60 at this level LL to
It is arranged between levels HL. The introduction section 60 is provided with control means such as a valve for adjusting the flow rate.

Next, the operation of this embodiment will be described. When the pulverizing classifier is driven, the primary airflow FA for transport classification
Passes through the damper 70, the duct heater 71, and from the nozzle 10 of the primary airflow introduction portion of the crushing chamber 3 to the outer closed casing 1
And is swirled into the classifying chamber 5. At this time, since the secondary airflow SA for transport classification is supplied from the secondary airflow introduction unit 60, the primary airflow FA rises while joining the secondary airflow SA, and passes through the guide vanes 13 to classify the air. Flows into the machine 11.

The raw material M in the mill feed bin 53 is supplied to the screw conveyor 51 via the rotary feeder 54, is sent to the screw conveyor 55, and drops from the outlet 55a of the screw conveyor 55 to the center of the grinding table 7. Crushed by a crushing roller 8.

The raw material BM, which has been finely pulverized, is
To the primary airflow FA for transport classification that is rotating inside
Ascends while riding and turning, but close to the secondary airflow introduction section 60
In the vicinity, the secondary air flow SA for transport classification is the primary air flow FA.
The raw material BM is mixed with the
Riding the combined swirling flow W, it rises further and passes through the guide vanes 13.
The air reaches the air classifier 11. Therefore, the raw material BM is
Classification twice during ascent from the crushing chamber 3 to the classification chamber 5, immediately
The primary airflow FA (airflow Q₁) And the primary
Mixing swirling flow W (air flow Q) of airflow FA and secondary airflow SA₁+
Q_Two) And will be subject to classification. In other words, primary
In the raw material BM that rises while turning on the airflow FA,
Coarse powder (A ₁, A_Two), Fine powder (B₁, B_Two), Fine powder C is mixed
However, of the coarse powder A, a large one (coarse powder A₁) Is one
It cannot fall on the swirling flow of the next airflow FA and falls downward.
Next, large coarse powder A₁The raw material BM from which the
It rises due to the circulating flow W, but of the coarse powder A, a small one (coarse
Powder A_Two) Is affected by the centrifugal force of the mixed swirling flow W.
It is pushed to the wall surface of the outer sealed casing 1 and
Comb falls down.

In this manner, the raw material BM from which the coarse powder A is separated into the fine powder B and the fine powder C flows into the classification gap 22 between the guide vanes 13 and the rotor blades 20, and the swirling flow (free vortex) 1-stage centrifugation. And
Of the fine powder B, the larger one (fine powder B ₁ ) is the guide vane 1
3 and separates from the flow of the carrier air and sequentially falls downward.

Then, of the fine powder B, a small one (fine powder B)
₂ ) and only the fine powder C flow into the vicinity of the rotor blade 20, and the fine powder B ₂ contained in the mixed gas flow is generated by the two-stage centrifugal separation action by the swirling flow (forced vortex) of the rotor blade 20.
Is repelled by the guide vanes 13 and falls.

The fine powder B (B ₁ , B ₂ ) is supplied to the hopper 1
2 slides down the inner surface and discharges horizontally from the fine powder outlet 40
2 and is sent to the entrance 43a of the calibration device 43 for calibration. After the completion of the calibration, the fine powder B is sent from the outlet 43b to the circulation circuit 50 via the rotary feeder 54, returned to the screw conveyor 51 again, and sent to the grinding chamber 3 together with the raw material M.

The fine powder C on the fine powder side, which has participated in the two-stage centrifugal separation operation, flows between the blades of the rotor blade 20 while turning, and is sent from the fine powder outlet 30 to the bag filter 32 via the mixed airflow, where it is turned. It is separated into C and air.
This fine powder C is stored in a container 81 on a platform scale 80 via a rotary valve 54.

The above is the outline of the operation of this embodiment. By increasing the gas flow rate of the secondary air stream SA conveying classifier outwardly closed casing 1 flow Q ₂ is introduced in this embodiment, the powder concentration (k for conveying classification of the flow rate to Q ₁ primary air flow FA
with following the g / m ³⁾ changes in reliably classifying efficiency is enhanced, the flow quantity Q _1, airflow ratio Q ₂ / Q ₁ of the flow rate Q ₂ wide, for example, be converted to 0 to 1.5 Classification room 5 by
Particle size distribution and powder concentration (kg / m
³ ) can be greatly adjusted as compared with the conventional example, and the particle size distribution width of the recovered fine powder can be controlled in a wide range.

Further, in addition to the operation of changing the air flow ratio Q ₂ / Q ₁ , the inclination angle of the guide vane 13, the rotor blade 2
By adjusting the number of rotations to 0, adjusting the classification gap 22 between the guide vanes 13 and the rotor blades 20, etc., the particle size distribution width can be greatly changed even with the same specific surface area, and the intrusion of coarse particles can be significantly prevented. Moreover, this change in airflow ratio Q ₂ / Q _1, the flow rate control means, for example, it is possible to simply control the valve, the operation is very simple.

A second embodiment of the present invention will be described with reference to FIG. The difference between this embodiment and the first embodiment is that a flake extracting means 90 such as a rotary valve or a double damper is provided between the crushing chamber 3 and the circulation circuit 50 so that flakes HF generated in the crushing chamber 3 can be removed from the outside. To the screw conveyor 51 via the circulation circuit 50 such as a conveyor, and then to the grinding chamber 3 together with the raw material M for grinding again.

By returning the flakes HF to the crushing chamber 3 and crushing again by the crushing roller 8, the conventional crushing limit in the crushing area can be further extended. According to the present embodiment, for example, in the case of fine pulverization of coal char (limestone), the product particle size distribution is 45, specific surface area (Brain value).
It is possible to approximately 000cm ² / g, compared to Blaine 27,000cm ² / g in the conventional example, it is possible to significantly reduce the pulverized.

A third embodiment of the present invention will be described with reference to FIG. The difference between this embodiment and the first embodiment is that, for example, a flake crusher 95 such as a pin mill, a novo rotor, or a jet mill is provided between the crushing chamber 3 and the circulation circuit 50 and is generated in the crushing chamber 3. The flake HF is crushed by the flake crusher 95, and the crushed flake HF is transferred to the switching chute CS.
Conveyor 51 through the circulation circuit 50 with
To the grinding chamber 3 together with the raw material M for grinding. The crushing machine 95 and the circulation circuit 50 constitute crushing / circulating / transporting means.

The switching chute CS is also connected to the secondary airflow introduction section 60. By operating the switching chute CS, the circulation circuit 50 and the introduction section 60 are communicated, and the fine powder of the crushed flakes is removed. The secondary airflow S is supplied to the introduction section 60 and
A, and may be circulated and transported to the classification chamber, and the coarse powder may be returned to the grinding chamber and re-ground.

By pulverizing the flake HF in this way, the efficiency of the fine pulverization can be further promoted. More specifically, it is possible to promote further pulverization in the fine powder region of the roller mill, and at the same time, to crush and pulverize the flakes in the pulverizing section as compared with a case where the flakes are not directly returned to the pulverization chamber without being pulverized. The bulk specific gravity of the material to be pulverized can be increased by adjusting the fineness of the pulverized powder to an appropriate value in accordance with various types of pulverized raw materials, and continuous stable operation can be performed.

Further, by the forced circulation by crushing the flakes, the trouble of the flake processing is eliminated, and the labor saving and the operation rate can be improved. Furthermore, since the vibration peculiar to the roller mill in the fine pulverizing region is remarkably reduced, by setting the pressing force of the pulverizing roller to an appropriate pulverized fineness according to various pulverized raw materials within the vibration allowable range, a high pressing force is obtained. Can be set arbitrarily. As a result, remarkable improvement in the pulverization efficiency is achieved, and it is possible to increase the hourly production of the product and reduce the unit of production power source (kwh / t).

FIG. 5 shows a control circuit used in this embodiment.
This will be described below. In FIG. 5, reference numeral 100 denotes a mill supply amount control circuit that controls a mill supply amount, 101 denotes a classifying air volume control circuit that performs a constant value control of a classifying air volume, 103 denotes a mill outlet temperature control circuit that performs a constant value control of a mill outlet temperature, and 105 denotes a mill outlet temperature control circuit. A mill power control circuit that performs constant power control of the mill power, 107 is a roller pressure control circuit that adjusts the pressure of the roller, 108 is a pressure reduction alarm switch of the control circuit 107, and 110 is a mill differential pressure control circuit. Show.

The supply of the mill is controlled by the changeover switch 37 so that the mill power (for example, power kw) of the vertical roller mill or the differential pressure (mmH ₂ O) between the inlet and the outlet of the mill body becomes constant. Is done.

The constant value control of the classifying air volume is performed by automatically changing the opening of the motor damper 102 of the exhaust fan 34.

The constant control of the mill outlet temperature is performed by automatically changing the temperature of the duct heater 71 at the mill inlet.

The constant value control of the mill power is performed by automatically changing the mill supply amount.

A fourth embodiment of the present invention will be described with reference to FIG. The difference between this embodiment and the third embodiment is that the horizontal discharge facility 42 is omitted, and the coarse powder outlet 40 of the inner hopper 12 opens toward the crushing chamber 3. Therefore,
In this embodiment, the fine powder B classified by the air classifier 11 falls directly into the crushing chamber 3.

An experimental example will be described. The present inventor compared the pulverizing and classifying apparatus of the conventional example with the pulverizing and classifying apparatus of the present invention.
0 rpm, vertical mill table rotation speed 50 rpm, vertical mill roller pressing force 3 tonf / 1 roller, exhaust fan air flow 25 to 50 m ³ / min, mill inlet damper opening 100% / primary air flow FA air flow Q ₁ 25 to 50 m ³ / min, air volume of the secondary air stream SA intake damper opening 48 to 100% / secondary airflow SA Q ₂ 5 to 15 m ³ / mi
The operation conditions were changed in the range of n, and a pulverization and classification experiment of charcoal (limestone) was performed.

As a result, “the average particle diameter D ₅₀ (μm) of the product (fine powder C) and the specific surface area (Brain value) of the product (cm ² )”
/ G) is as shown in FIG. 7, and the relationship between "mill power consumption unit (kwh / t) and specific surface area (Brain value) (cm ² / g) of product" is as follows. As shown in FIG.

In FIG. 7, the horizontal axis represents the specific surface area (Brain value) of the product (cm ² / g), and the vertical axis represents the average particle diameter D of the product.
₅₀ (μm), the vertical line X ₁ is the grinding limit of 27.0
00 cm ² / g.

[0057] I3~I5 is, in addition to the secondary air stream SA air flow rate of air flow rate of the primary air flow FA (primary air flow rate) Q ₁ (secondary air flow rate)
Is a case where the introduction of Q _2. The number following I indicates the number of revolutions (1,000 rpm) of the classification rotor blade. For example, I3 is a rotation speed of 3 × 1,000 rpm. The number following the flow rate Q ₃ = of the mixed swirling flow W is the total flow rate (m ³ / min) of the primary air flow rate Q ₁ + the secondary air flow rate Q ₂ . Since the air volume to Q ₁ primary air flow is maintained at 35m ³ / min, for example, Q ₃ = 50 is the air volume of mixed swirling flow 50 m ³
/ Min, and air flow rate Q ₂ of the secondary airflow 15 m ³ / min, and made.

[0058] E3~E5 is, only the primary air flow Q _1, that is,
A case of not introducing the secondary air flow Q _2, the next number of E classifier rotor blade speed (unit 1,000rp
m). For example, E3 is a rotation speed of 3 × 1,000 rpm. The number following the primary air flow Q ₁ = is the air volume m ³ / m
in, and L following the number indicates that it is on the line of the air volume of the number. For example, when Q ₁ = 47, the air volume of the primary air flow is 47 m ³ / min, and Q ₁ = 40 L, when the primary air flow Q ₁
= 40 m ³ / min.

As is apparent from this figure, the primary air flow rate Q ₁
Only, i.e., secondary air flow rate if Q ₂ and does not introduce, the particle size range of change in the distribution range surrounded by curves of E3～E5, i.e., Blaine value of about 38,000cm ² / g~18,00
It is a curve part in the range of 0 cm ² / g.

The change range of the particle size distribution when the secondary air flow rate Q ₂ is introduced is a curve portion from the intersection P3 to P5 on the right side of the range surrounded by the curves I3 to I5, that is, a Blaine value of about 34, 000cm ² / g-18,000cm ² / g
Is a curve portion in the range of. This intersection P3 to P5
Is an intersection point of the curve I3~I5 of the case of introducing the curve E3~E5 of the case of introducing only to the primary air flow and the secondary air flow rate Q _2. Comparing the curved portion of each of, it can be seen that it is possible to change significantly the particle size distribution in the same specific surface area by the introduction of the secondary air flow rate Q _2.

Incidentally, the average particle diameter D ₅₀ (μm) of the product can be greatly changed even for the fineness of the same specific surface area.
Particle size distribution width of the product is greatly changed, furthermore, a result of the introduction of the secondary air flow rate Q ₂ is significantly less dive coarse particles.

In FIG. 8, the horizontal axis indicates the specific surface area (Brain value) (cm ² / g) of the product, the vertical axis indicates the mill power unit (kwh / t), and the vertical line X ₂ indicates poor classification performance. Position of the crushing limit of the classifier (Brain value 20,000 cm ²
/ G) and X ₃ indicate the position of the pulverization limit (Brain value 28,000 cm ² / g) when the performance is good.

[0063] The vertical line X ₃ right, i.e., curve I6 direction side of Blaine value is increased, is discharged flakes from the grinding chamber, the case was returned to the grinding chamber through the circulation circuit, the curve I7 is after crushing drained flakes from the grinding chamber, a case where the entrained coarse powder and fine powder in the secondary air flow Q ₂ and returned to the grinding chamber. When the flakes are discharged from the crushing chamber and crushed, and then returned to the crushing chamber via the circulation circuit, I8
Is a value between the curves I6 and I7. The number of revolutions of the classifier rotor blade in this figure is 5,000.
rpm, dam ring is 20mm, the primary air flow rate Q ₁ 25
４５45 m ³ / min.

As is clear from this figure, the flakes are not crushed but are forcedly circulated and returned to the crushing chamber, and the flakes are forcibly crushed. The pulverization limit can be extended to about 000 cm ² / g.

After the flakes have been crushed, they are returned to the crushing chamber.
Or secondary powder flow Q _TwoAnd mix the coarse powder
Returning to the grinding chamber accelerates fine grinding (in the case of charcoal)
Is a Brain value of 45,000cm^Two/ G) becomes possible
In both cases, the remarkable increase in the hourly production of products and the power consumption unit (kw)
h / t) can be reduced.

In the above experiment, the position of the secondary airflow introduction unit 60 is an example immediately below the lower part of the classifier 11, but the experimental results obtained by changing the position of the secondary airflow introduction unit 60 other than the present experimental example are as follows. Although not shown, similar results were obtained. That is, even when the secondary airflow introduction unit 60 is introduced near the upper part of the pulverizing unit (pulverizing chamber), or at an intermediate position between the upper part of the pulverizing chamber and the lower part of the classifier, the secondary airflow introducing unit 60 depends on the position of each introducing part 60. It shows a similar tendency.

These relationships will be described with reference to FIGS. FIG. 10 is an illustration of a conventional example. In the case where the casing between the pulverizing chamber and the classifying chamber is of three types, a high side H, a standard S, and a low side L, the degree of fineness OD and Illustrated IL, IS,
Indicated by IH. The degree OD of this fineness, the ID, rectangular HS hatched is if the primary gas flow rate Q ₁ is larger, also plain rectangular WS its inner is the case the primary air flow rate Q ₁ is small. The longer the length LM of the rectangle is, the coarser it is.

[0068] As can be understood from this illustration, the primary air flow rate Q ₁ is as long as the same air volume, in the case of the low-side L recovering what is most coarse powder of the product on the air classifier. Therefore, the coarse powder after classification also becomes coarse, and the discharged powder becomes the coarsest at the stage of being discharged from the pulverizing chamber. Reach the entrance and classify the coarsest with a classifier.

The degree of fineness OD at the outlet of the primary airflow adjusting nozzle 10 and the degree of fineness ID at the entrance of the classifying chamber are ascending and turning while the casing becomes finer in the order of standard S and high side H, and reach the classifier inlet. The illustration shows that the casing is finely classified in the order of standard S and high side H in the classifier.

FIG. 9 is an illustration of the present invention. The pulverized raw material is introduced from the nozzle 10 of the pulverizing chamber into the primary air flow FA swirling toward the classifying chamber by introducing a secondary air flow SA in a tangential direction in the same direction as the primary air flow, thereby increasing the air flow and thereby increasing the primary air flow. the method of controlling the particle size distribution of the flow rate Q ₁ and the secondary air flow rate Q ₂ and a flow rate ratio Q ₁ / Q ₂ changes while pulverized product described in the illustration.

As will be understood from this illustration, the same concept as described with reference to FIG. 10 can be applied to this description. Degree of fineness OD at outlet of primary air flow adjusting nozzle 10
Becomes rough and the air flow rate Q ₁ of the primary air flow FA is large, located in the finer relationship with less. As described with reference to FIG. 10, when a secondary airflow is introduced from the lower secondary airflow inlet 60C, the degree of fineness ID at the classifier inlet becomes coarse and the particles are conveyed to the classifier. Therefore, since the classification conditions of the classifier are constant, the coarse powder after classification becomes coarse, and the discharged powder becomes coarse at the stage of being discharged from the crushing chamber. Furthermore, since the secondary airflow SA is introduced from the lower secondary airflow inlet 60C, the airflow of the upward swirling flow further increases and reaches the classification chamber 5 inlet with a coarse fineness and is classified most coarsely by the classifier. Illustration I
L indicates.

The degree of fineness ID with respect to the classification chamber inlet becomes smaller in the order of the middle secondary air inlet 60B and the upper secondary air inlet 60A.
Secondary air flow SA from the upper secondary air inlets 60B and 60A
Is introduced, the ascending swirling flow is further strengthened and reaches the classifier inlet with a coarser fineness. In the classifier, the middle secondary air inlet 60B and the upper secondary air inlet 60A are provided.
The illustrations IM and IT show that classification is performed in the order of.

FIG. 9 also includes the relationship with the illustration of FIG. 10 when the casing is high side H, standard S, and low side L. That is, the crushing chamber 3 and the classifying chamber 5
It is shown that the purpose can be achieved only by introducing the secondary airflow SA without having to change the height of the casing between them as needed. This means that even with a fineness of the same specific surface area (cm ² ), the average particle diameter D ₅₀ (μm), the fine particle ratio (%) and the coarse particle ratio (%) in the product can be adjusted, and the particle size distribution width is broad. This indicates that the powder can be sharply controlled from the beginning.

The pulverized raw material used in this experiment was charcoal (limestone), but other pulverized raw materials such as talc,
Similar results were obtained with slag powder and silica stone.

The embodiments of the present invention are not limited to the above, and it goes without saying that changes can be made as appropriate without departing from the spirit of the present invention.

[0076]

The present invention has the following remarkable effects. (1) A particle size distribution adjusting means is provided between the upper end level of the pulverizing roller in the pulverizing chamber and the lower right lower end surface level of the classifying chamber, and introduces a secondary air stream for transport classification into the transport swirl flow. Therefore, as compared with the conventional example, it is possible to greatly change the particle size distribution and enhance the operability function of easily controlling the change. (2) Since the flakes discharged from the vertical roller mill are crushed and then returned to the classifying chamber or the crushing chamber, further pulverization in the fine powder region of the roller mill is promoted and crushing efficiency is improved. At the same time, the bulk specific gravity of the material to be crushed and crushed in the crushing chamber is set to an appropriate crushing fineness according to various crushing materials, as compared with the case where the flakes are directly returned to the crushing chamber without being crushed. Can be increased.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is a sectional view taken along line III-III of FIG. 2;

FIG. 4 is a diagram showing a second embodiment of the present invention.

FIG. 5 is a diagram showing a third embodiment of the present invention.

FIG. 6 is a diagram showing a fourth embodiment of the present invention.

FIG. 7 is a graph showing experimental results.

FIG. 8 is a graph showing experimental results.

FIG. 9 is an illustration showing the relationship between the position of the secondary airflow inlet and the particle size distribution according to the present invention.

FIG. 10 is an illustration showing the relationship between the height and the particle size distribution of a conventional casing.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 outer closed casing 3 crushing chamber 5 classifying chamber 8 crushing roller 11 air classifier 12 inner hopper 20 rotor blade 50 circulation circuit 60 secondary airflow inlet 95 flake crusher

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Shinichi Shimamura, Inventor 3-8-1, Nishikanda, Chiyoda-ku, Tokyo Inside Noda Engineering Co., Ltd. (72) Fumio Kawano 3--8, Nishikanda, Chiyoda-ku, Tokyo No. 1 Inside Onoda Engineering Co., Ltd. (72) Inventor Kantaro Kantaro 1-12-19 Kitahorie, Nishi-ku, Osaka City, Osaka Prefecture Inside Kurimoto Ironworks Co., Ltd. (72) Inventor Masaru Ogata 1-chome, Kitahorie, Nishi-ku, Osaka City, Osaka Prefecture No. 12-19 Inside Kurimoto Iron Works, Ltd.

Claims (11)

[Claims] 1. A vertical roller mill crushing chamber provided at a lower part of an outer sealed casing, an air classifying chamber provided at an upper part of the outer sealed casing, and a primary air flow for transport classification introduced into the outer sealed casing. A pulverizing classifier having a nozzle for forming a swirling flow from the pulverizing chamber to the classifying chamber and feed means for supplying a pulverized raw material to the pulverizing chamber; Disposed between the level and the lower right bottom surface level of the classifying chamber,
A pulverizing and classifying apparatus, further comprising a particle size distribution adjusting means for introducing a secondary air flow for transport classification into the transport swirl flow. 2. A vertical roller mill pulverizing chamber provided at a lower portion of the outer sealed casing, an air classifying chamber provided at an upper portion of the outer sealed casing, and a primary airflow for transport classification is introduced into the outer sealed casing. A pulverizing classifier having a nozzle for forming a swirling flow from the pulverizing chamber to the classifying chamber and a feeding means for supplying a pulverized raw material to the pulverizing chamber; A pulverizing and classifying apparatus, wherein a pulverizing / circulating / conveying means for pulverizing the flakes to be fed to the feeding means is provided. 3. A vertical roller mill crushing chamber provided at a lower portion of the outer sealed casing, an air classifying chamber provided at an upper portion of the outer sealed casing, and a primary air flow for transport classification introduced into the outer sealed casing. A pulverizing classifier having a nozzle for forming a swirling flow from the pulverizing chamber to the classifying chamber and feed means for supplying a pulverized raw material to the pulverizing chamber; Disposed between the level and the lower right bottom surface level of the classifying chamber,
And a particle size distribution adjusting means for introducing a secondary air stream for transport classification into the transport swirling flow; and a crushing and circulating transport means for crushing flakes discharged from the vertical roller mill crushing chamber and sending the flakes to the feeding means. And a pulverizing and classifying apparatus, comprising: 4. The pulverizing and classifying apparatus according to claim 1, wherein the particle size distribution adjusting means includes a flow ratio control device. 5. The particle size distribution adjusting means includes a secondary airflow introduction unit, and a crushing / circulating / conveying means is connected to the feeding means via a switching chute. 4. The pulverizing and classifying apparatus according to claim 3, wherein the pulverizing and classifying apparatus is connected to a secondary airflow introducing section. 6. A step of supplying a pulverized raw material to a vertical roller mill pulverizing chamber provided at a lower portion of the outer closed casing, and pulverizing the pulverized raw material, forming the pulverized raw material in the outer closed casing, and A pulverizing classifier comprising: a step of transporting the raw material conveyed to the air classifying chamber from a transport swirl flow; and a step of classifying the raw material conveyed to the air classifying chamber by air; Pulverizing and classifying, wherein a secondary airflow for transport classification is introduced from a tangential direction into the transport swirling flow located between an upper end level of the above and a lower right lower end surface level of the classification chamber. 7. A step of supplying a pulverized raw material to a vertical roller mill pulverizing chamber provided at a lower portion of the outer closed casing, and pulverizing the pulverized raw material, forming the pulverized raw material in the outer closed casing, and A pulverizing and classifying method comprising a step of transporting the raw material conveyed to the air classifying chamber by carrying it on a swirling flow, and a step of air classifying the raw material transported to the air classifying chamber; A crushing classification method, comprising: crushing discharged flakes and returning the flakes to the crushing chamber via a feeding means for supplying a crushed raw material. 8. A step of supplying a pulverized raw material to a vertical roller mill pulverizing chamber provided at a lower portion of the outer closed casing, and pulverizing the pulverized raw material, forming the pulverized raw material in the outer closed casing, and A pulverizing classifier comprising: a step of transporting the raw material conveyed to the air classifying chamber from a transport swirl flow; and a step of classifying the raw material conveyed to the air classifying chamber by air; In the transport swirling flow located between the upper end level of the classification chamber and the lower right lower end surface level of the classification chamber, a secondary air flow for transportation classification is introduced from a tangential direction, and flakes discharged from the vertical roller mill pulverizing chamber are removed. ,
A pulverization classification method, wherein the pulverization raw material is returned to the pulverization chamber via a feeding means. 9. A step of supplying a pulverized raw material to a vertical roller mill pulverizing chamber provided at a lower portion of the outer closed casing, and pulverizing the pulverized raw material, forming the pulverized raw material in the outer closed casing, and pulverizing the pulverized raw material. A pulverization classification method comprising: a step of transporting the raw material transported by the transport swirl flow from the chamber to the air classification chamber; and a step of air-classifying the raw material transported to the air classification chamber; In the transport swirling flow located between the upper end level of the roller and the lower right lower end surface level of the classification chamber, a secondary air flow for transport classification is introduced from a tangential direction, and flakes discharged from the vertical roller mill grinding chamber. Pulverizing and then returning the pulverized raw material to the pulverizing chamber via a feeding means for supplying a pulverized raw material. 10. A step of supplying a pulverized raw material to a vertical roller mill pulverizing chamber provided at a lower portion of an outer closed casing, and pulverizing the pulverized raw material, forming the pulverized raw material in the outer closed casing, and pulverizing the pulverized raw material. A pulverizing and classifying method comprising: a step of transporting the raw material transported by a transport swirl flow from a chamber to an air classification chamber; and a step of air-classifying the raw material transported to the air classification chamber; In the transport swirl flow located between the upper end level of the roller and the lower lower end surface level of the classification chamber, a secondary air flow for transport classification is introduced from a tangential direction, and the flakes discharged from the vertical roller mill pulverization chamber. Crushing, and then supplying the crushed material to an introduction portion of the secondary air stream for transport classification. 11. The method according to claim 6, wherein the introduction amount of the secondary airflow for transport classification is adjustable.
0. The pulverization classification method according to 0.