JPH10277416A - Production method of sand and sand producing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and its device for producing sand by which the crushed sand stabilized in quantity and having a desired grain size distribution based on an FM value is automatically produced at a low product cost with the inexpensive device. SOLUTION: A raw sand to be supplied from a crushed raw sand feed line is crushed by a sand producing machine consisting of a cage mill provided with a classifying function, a part of the crushed product is returned by a fixed ratio to the feed line as the raw sand of the cage mill. In this case, a sand producing device is composed of the crushed raw sand feed lines 12 and 1, a sand producing machine 2 consisting of the cage mill provided with the classifying function for crushed and classifying the crushed raw sand supplied from the crushed raw sand lines, a distributor 3 for distributing the crushed product from the sand producing machine 2 by a specified ratio, a product pulverized sand producing line connected to one of the distributed side of the distributor 3 and a returning means 4 connected to the other side of the distributed side of the distributor 3 and returning a part of the crushed by a fixed ratio product from the sand producing machine 2 to the sand producing machine 2 side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sand making method capable of crushing and sand making a crushed sand raw material by a predetermined sand making means to produce a crushed sand having a desired coarse particle size distribution such as a single sand and the like. The present invention relates to a sand making device suitable for use in carrying out the method. The single sand refers to sand that can be used as it is as a raw material for concrete or the like without requiring any mixing operation such as mixing with natural sand at a demand destination.

[0002]

2. Description of the Related Art Typical prior art of this type of dry sand making apparatus used in sand making plants and the like is disclosed in Japanese Patent Publication No. 58-900 (first conventional example) and Japanese Utility Model Publication No. 4-909 (No. 2 conventional example) and JP-A-8-173835 (third conventional example).

[0003] In the first prior art, the crushed product of the primary crusher is sieved into coarse aggregate on a sieve and crushed sand passing through a sieve, and the crushed sand passed through the sieve and coarse aggregate having a small particle size are further sized. It is sieved by the following sieves, and those that do not pass through the sieve are crushed by a secondary crusher. Thereafter, a part of the crushed product of the secondary crusher and the crushed sand having a small particle size passing through the sieve surface are supplied to a dry classifier, and the remaining crushed product of the primary crusher and the crushed sand classified by the dry classifier are provided. Is supplied to a humidifying mixer, and a series of treatments of mixing with moisture are performed to produce sand.

[0006] The particle size distribution of the crushed product obtained by crushing a general crushed sand material with each type of conventional dry crusher including the first prior art example was examined.
The result as shown in FIG. That is, referring particularly to FIG. 6 in FIGS. 6 and 7, in order to obtain the above-mentioned crushed product that can be used as single sand, FIG.
(B) must have a particle size distribution within the particle size range defined by the Japan Society of Civil Engineers, represented as the area between the two broken lines, but any crushed products obtained by those dry crushers However, those having a sieve nominal size of 0.6 mm to 0.15 mm are insufficient.

[0005] Crushed sand having such a particle size structure is generally used for blending with natural sand, for example, and cannot be used as single sand.
In this regard, in the first conventional example, the FM value (Fineness M
odule: Coarse particle size of product crushed sand) No adjustment or adjustment of particle size distribution was made, so crushed sand obtained by crushing and classification had a particle size distribution as shown in Fig. 6 (B). As a result, it cannot be used as the single sand targeted by the present invention. However, if a cage mill as a dry crusher is used at a very high rotation speed, the crushing performance may be improved and it may be possible to produce single sand depending on the raw material. Is extremely fast and cannot be used in a short period of time.

On the other hand, the second conventional example is such that a crushed product from a dry crusher is distributed by a distribution chute and a part thereof is returned to the dry crusher. The distribution chute can change the distribution ratio. It has a structure, and the particle size of the crushed product is adjusted by adjusting the distribution ratio. However, in the second conventional example, when the distribution ratio of the distribution chute is changed, the production amount of the crushed product naturally changes accordingly. Therefore, for example, the production amount of the product every month is not stable, There is a problem that it is difficult to make an accurate production plan. In addition, since the supply amount to the dry crusher also changes depending on the distribution ratio, there is a disadvantage that the operation state is likely to be unstable.

In this second conventional example, it is said that the FM value can be adjusted. However, there is no mention of the adjustment of the particle size distribution suitable for the range of the Japan Society of Civil Engineers as shown in FIG. Therefore, even if the FM value is an appropriate value, it is sufficiently considered that the FM value is out of the range of the aforementioned Japan Society of Civil Engineers. Also in the case of the second conventional example, the first point is that it is difficult to obtain crushed sand usable as single sand. This is the same as the conventional example.

The third prior art is a technique relating to a method for producing crushed sand using a rod mill as a crushing means, and is capable of producing crushed sand having a desired particle size distribution. Since it is a treatment method, there is a problem that turbid water treatment requires a long time and high cost, and therefore, it is a method significantly different from the dry crushing intended by the present invention.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems of the prior arts.
Another object of the present invention is to provide a sand making method and a sand making method capable of automatically producing crushed sand having a desired particle size distribution on the basis of an FM value, and capable of producing the sand at low equipment cost and low product cost.

[0010]

The present invention has the following configuration to achieve the above object. That is, in the present invention, the invention according to claim 1 crushes and classifies the crushed sand raw material supplied from the crushed sand raw material supply line by a sand maker comprising a cage mill having a classification function, and a part of the crushed product is separated by a predetermined ratio. It is a sand making method characterized in that only the cage mill raw material is returned to the crushed sand raw material supply line.

[0011] According to the present invention, in the state where the properties (rock quality, size, etc.) of the crushed sand material are small and substantially stable, the crushed product can be obtained by a fixed crushed sand distribution ratio adapted to the crushed sand material. By returning to the crushed sand raw material supply line, the particle size distribution of the crushed sand raw material can be made finer, and crushed sand that is likely to be insufficient in the size range of the sieve nominal size of 0.6 mm to 0.15 mm is replenished, and the desired Crushed sand with particle size distribution,
For example, it is possible to always produce single sand in a stable amount. Also, by having the sand maker have a classification function,
Usually, a dedicated classifier required for a sand making device can be omitted to make the equipment compact. It should be noted that the cage mill is an impact-type fine pulverizer, and has a feature that high-quality crushed sand can be obtained at a low running cost.

Further, according to the invention of claim 2, the crushed sand raw material supplied from the crushed sand raw material supply line is crushed and classified by a sand maker comprising a cage mill having a classification function, and the crushed product is periodically and automatically crushed. A sand making method characterized by sampling and automatically measuring the particle size distribution, and controlling the rotation speed of a cage mill so that the measurement result meets predetermined setting conditions.

According to the present invention, even when the properties of the raw material for crushed sand change or when the crushing performance of the sand maker changes, crushed sand having a constant particle size can always be produced.

According to a third aspect of the present invention, a crushed sand raw material supplied from a crushed sand raw material supply line is crushed and classified by a sand maker comprising a cage mill having a classifying function, and a part of the crushed product is separated by a predetermined ratio. Only the cage mill raw material is returned to the crushed sand raw material supply line, while the crushed product is periodically and automatically sampled, its particle size distribution is automatically measured, and the cage mill is rotated so that the measurement result matches the predetermined setting conditions. A sand making method characterized in that the number is controlled.

According to the present invention as described above,
These characteristics are also exhibited, and it is possible to produce qualitatively and quantitatively stable high-quality crushed product sand.

A fourth aspect of the present invention is a sand making machine comprising a crushed sand material supply line including a conveying device, and a cage mill having a classifying function of crushing and classifying the crushed sand material supplied from the crushed sand material supply line. A distribution device for distributing the crushed product from the sand making machine at a predetermined distribution ratio, a product crushing sand production line connected to one of the distribution devices, and a distribution device connected to the other distribution side of the distribution device. And a return means for returning a part of the crushed product from the sand maker to the crushed sand raw material supply line by a fixed ratio.

According to the present invention, crushed sand having a desired particle size distribution, for example, single sand, can always be produced in a stable amount with low equipment cost and low running cost.

A fifth aspect of the present invention provides a sand maker comprising a crushed sand material supply line including a transport device, and a cage mill having a classifying function of crushing and classifying the crushed sand material supplied from the crushed sand material supply line. A product crushed sand production line connected to a crushed product extraction section of the sand maker, and a particle size distribution measuring means for periodically and automatically sampling the crushed product in the product crushed sand production line and automatically measuring the particle size distribution thereof And a rotation control means for controlling the number of rotations of the cage mill so that the measurement result of the particle size distribution measurement means conforms to a predetermined setting condition.

According to the present invention, it is possible to always produce crushed sand having a constant particle size even when the properties of the crushed sand raw material change or when the crushing performance of the sand maker changes.
Moreover, it has the feature that the apparatus cost and running cost can be kept low.

A sixth aspect of the present invention is a sand making machine comprising a crushed sand raw material supply line including a conveying device, and a cage mill having a classifying function of crushing and classifying the crushed sand raw material supplied from the crushed sand raw material supply line. A distribution device for distributing the crushed product from the sand making machine at a predetermined distribution ratio, a product crushing sand production line connected to one of the distribution devices, and a distributing device connected to the other distribution side of the distribution device. Return means for returning a portion of the crushed product from the sand maker to the crushed sand raw material supply line by a fixed ratio, and periodically and automatically sampling the crushed product in the product crushed sand production line, Sand making equipment by means of particle size distribution measuring means for automatically measuring the particle size distribution, and rotation control means for controlling the rotation speed of the cage mill so that the measurement result of the particle size distribution measuring means conforms to a predetermined setting condition. One in which you configure.

According to the present invention as described above,
By combining these features, it is possible to produce qualitatively and quantitatively stable high-quality crushed sand at low equipment costs and low running costs.

According to a seventh aspect of the present invention, in the sand making device according to the fifth or sixth aspect, the predetermined setting condition is that the rotation speed of the sand maker and the FM value corresponding to the rotation speed are different. It is based on a database determined by the relationship.

According to the present invention, there is further provided a feature in that crushed sand having a desired particle size can be stably and automatically produced based on the setting conditions written in the database. Can be

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. FIG.
(A) schematically shows the configuration of the embodiment of the present invention. The sand-making apparatus includes a sand-crushing material supply line formed by including a sand-crushing material bin 12 and a supply device 1, a sand-making machine (hereinafter, referred to as a cage mill) 2 including a cage mill having a classification function, and a distribution device 3. And a return unit 4, a product crushed sand production line including the humidifier kneader 8, and a control unit 6 for controlling the operation of the sand maker 2. The sand making device according to the present invention may have a sieve device (not shown) interposed between the sand making device 2 and the distribution device 3.
In some cases, the humidifier 8 may not be used.

FIG. 1B shows an example of the structure of the cage mill 2. The rotor portion of the cage mill 2 includes a small rotor 23 having a pin shield 25 and a large rotor 24 having a pin shield 26. The rotors 25 and 26 are coaxially opposed to each other so as to intersect with each other in the radial direction of the rotor, and rotate in opposite directions.
Are integrally attached.

Such a cage mill 2 has two rotors 2.
3 and 24, the raw material (crushed sand raw material) R input from the entrance is rotated by the pin shields 25 and 26.
While being pulverized by the classifying blades 19, the pulverized material P1 and the fine powder P2 are classified, and the pulverized material P1 is discharged from one outlet provided at a lower portion, and the fine powder P2 is provided at the other upper portion provided at a right upper portion. After passing through the outlet, the dust is collected by the dust collecting device 7 connected to the outlet. In this way, the crushing and classification can be performed by a single device.

Referring to FIG. 1A, the crushed sand raw material is supplied from a crushed sand raw material bin 12 to a cage mill 2 through a supply device 1. As the supply device 1, for example, a fixed-quantity cutting device including an electromagnetic feeder is used. The cage mill 2 performs a crushing operation by rotating a rotor at an appropriate speed in a range of a peripheral speed of 20 to 50 m / s, and a part of the crushed material is transferred from a conveyor such as a belt conveyor by a distribution device 3 realized by a damper. The material is returned to the cage mill 2 as a raw material by returning to the crushed sand raw material supply line via the return means 4. At that time, the ratio returned by the return means 4 is determined in accordance with the type and size of the crushed sand raw material within the range of 50 to 0%, and is fixed unless there is a change in this property.

The remaining crushed products distributed and taken out by the distribution device 3 are humidified and kneaded by the humidifying and kneading machine 8 of the product crushed sand production line to produce product crushed sand 20. In addition,
The fine powder 21 classified by the cage mill 2 is stored separately from the product crushed sand 20 through the dust collector 7.

As described above, the FM value representing the properties of the product crushed sand 20 produced by the embodiment of the present invention which performs crushing and classification with partial return is shown in FIGS. 2 and 3 as comparative examples. As shown in FIG. 2, as shown in FIG.
In the case of producing product crushed sand in the range of 2.8, for hard sandstone, the FM value is 2.71 to 0.17 without return.
Since only 3.14 can be adjusted, the desired performance is not achieved, whereas a 25% return provides an FM value of 2.
An adjustment of 6 to 2.8 is possible. With diorite this can be achieved without a return. With andesite, only the FM value of 2.75 to 3.30 can be adjusted without a return, so the desired performance is not achieved. On the other hand, a 40% return results in an FM value of 2.6 to 2.8. Can be adjusted.

Further, as shown in FIG.
In the case of producing product crushed sand having an FM value in the range of 2.6 to 2.8 using the raw material of the above, in the case of quartz rough rock, only the FM value of 2.85 to 3.07 can be adjusted without return,
If the desired performance is not reached, the FM value can be adjusted to 2.6 to 2.8 by setting a 35% return.
For sandstone, FM value 2.98-3.5 without return
7 can be adjusted, so that the desired performance is not achieved. On the other hand, by setting the return to 50%, the FM value of 2.6 to
An adjustment of 2.8 is possible. In the case of hard sandstone, only the FM value of 2.77 to 3.33 can be adjusted without a return, so that the desired performance is not achieved. On the other hand, by setting the return to 35%, the FM value of 2.6 to 2.3. Eight adjustments are possible.

By setting the return-side distribution ratio to a predetermined ratio within the range of 0 to 50% in accordance with the properties of the raw material, it is possible to stably produce crushed sand having a predetermined FM value. It is possible.

On the other hand, regarding the properties of the product crushed sand 20 when the rotation speed of the cage mill 2 is controlled, the product particle size distribution table shown in FIG. 5 (B) is as illustrated in the product particle size distribution diagram. According to this example, the cage mill 2 peripheral speed: 35 m / s, the return side distribution ratio 0%, the cage mill 2 peripheral speed:
35m / s, return side distribution ratio 25%, cage mill 2 peripheral speed: 4
As is clear from the comparison results of the three cases of 0 m / s and the return side distribution ratio of 25%, the particle size distribution can be adjusted by changing the peripheral speed of the cage mill 2 at the return side distribution ratio of 25%. FIG. 5B shows that the particles can fall within the granularity range of the Japan Society of Civil Engineers, which is indicated by the range between two broken lines in FIG.
That is, product crushed sand 20 that can be used as single sand
Can be produced.

Next, the control means 6 for controlling the operation of the cage mill 2 will be described with reference to FIG. The control means 6 includes a sampling device 9, a particle size distribution measuring device 10 realized by an automatic particle size measuring device, and a rotation control device comprising a controller for controlling the number of rotations of a motor (not shown) for driving the cage mill 2. 11. The sampling device 9 is interposed in the crushed material line from the dry classifier 5 to the humidifying kneader 8 so that a part of the crushed material at the outlet of the dry classifier 5 can be periodically sampled. In addition,
The sampling device 9 may be provided so as to be able to sample the crushed product from the cage mill 2 to the dry classifier 5. The particle size distribution measuring means 10 measures the particle size distribution of the crushed material sampled by the sampling device 9, records the measurement result, and stores the measurement result in a memory as particle size information. Rotation control means 11
Is configured to compare the measurement result (FM value) of the particle size distribution measuring means 10 with a preset target FM value, and to control the rotation speed of the motor so that both values match.

The mode of operation control by the control means 6 is as shown in the control flow of steps S1 to S5 in FIG. 4, and the particle size information obtained by the particle size distribution measuring means 10 is fed back to the cage mill 2. ,
The product crushed sand 20 which always maintains a stable particle size can be produced. In addition, the cycle of the automatic particle size measurement is 30 to 60 mi.
It shall be set to an appropriate value in the range of n.

As for the control means 6, a database 27 is prepared as shown in FIG. It is a preferable means to keep it as information. In the database 27, the relationship between the rotation speed of the cage mill 2 and the corresponding FM value is obtained by experiment in advance for each type of the crushed sand material, and is used as data. If an arbitrary FM value is input to the control means 6 as setting information based on the database 27, the cage mill 2 can be automatically controlled at an appropriate rotation speed, and the desired granularity (F
M) The product crushed sand 20 can be stably produced.

[0036]

The present invention is embodied in the form described above and has the following effects. According to the inventions of claims 1 and 4, by returning a part of the crushed product of the cage mill as a raw material of the cage mill by a certain ratio, the particle size distribution of the product crushed sand can be reduced to a small fluctuation state. 0.6-
Crushed sand with a particle size range of 0.15 mm is replenished, enabling the production of single sand. In addition, the production amount can be kept constant with a small amount of fluctuation and always stable.

Further, since the cage mill is provided with a classifying function, a classifier separately provided in a product crushed sand production line is not normally required, so that the installation space for sand making equipment can be reduced, and initial and running costs can be reduced. Also, maintenance work can be saved.

Further, according to the second and fifth aspects of the present invention, it is possible to always produce crushed sand having a constant particle size even when the crushed sand raw material conditions fluctuate or when the crushing performance of the cage mill is reduced due to wear. In addition, according to the invention of claim 5, crushed sand having a desired particle size (FM value) can be stably produced.

According to the third and sixth aspects of the present invention, qualitatively and quantitatively stable, high-quality product crushed sand can be produced at low equipment cost.
It can be produced at low running cost.

According to the seventh aspect of the present invention, the effect of stably and automatically producing crushed sand having a desired particle size based on the setting conditions written in the database can be obtained. More will be added.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention.

FIG. 2 (A) is a table showing the relationship between the cage mill peripheral speed and the FM value with respect to the rock quality and the return ratio of the product crushed sand produced from the raw material having a particle size of 5 to 2.5 mm according to the embodiment of the present invention and the comparative example. The same table (B) is also a diagram.

FIG. 3 (A) is a table showing the relationship between the peripheral speed of a cage mill and the FM value for each type of crushed sand and return ratio of crushed product manufactured from a raw material having a particle size of 13 to 5 mm according to an embodiment of the present invention and a comparative example. , (B) are also diagrams.

FIG. 4 is a flow chart of cage mill rotation control according to the embodiment of the present invention.

FIG. 5 (A) is a product particle size distribution table showing the relationship between the sieve nominal size and the weight percentage of the crushed product manufactured by the embodiment according to the present invention, and (B) is a product particle size distribution diagram similarly. .

FIG. 6 (A) is a product particle size distribution table showing the relationship between the sieve nominal size and weight percentage of product crushed sand crushed by various conventional dry crushers, and FIG. 6 (B) is also a product particle size distribution diagram.

FIG. 7 (A) is a product particle size distribution table showing the relationship between the sieve nominal size and the percentage of passage of product crushed sand crushed by various conventional dry crushers, and FIG. 7 (B) is also a product particle size distribution diagram.

[Explanation of symbols]

1 ... fixed-quantity feeding device, 2 ... sand maker, 3
... Distributor, 4 ... Return means 4, 5 ... Classifier,
6 control means, 7 dust collector, 8
... humidifying kneader, 9 ... sampling device, 10 ...
Particle size distribution measuring means, 11: rotation control means, 12: crushed sand raw material bottle, 13: cone crusher, 14: first sieve,
15: second sieve, 16: transport device, 1
7 ... Damper, 20 ... Crushed product, 21 ... Fine powder,
22: crushed stone, 23: small rotor, 24: large rotor, 25: pin shield,
26 ... pin shield, 27 ... database,

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Masayuki Kano 2-3-1 Shinhama, Arai-machi, Takasago City, Hyogo Prefecture Inside Kobe Steel, Ltd. Takasago Works (72) Inventor Sosuke Naito 2-6, Nishitenma, Kita-ku, Osaka-shi 8 Do Building Seki Nishi Matek Co., Ltd. (72) Inventor Hiroaki Tanaka 2-6-8 Nishi Tenma Kita-ku, Osaka City Do Building Seki Nishi Matek Co., Ltd. (72) Inventor Kazu 2-6 Nishi Tenma Kita-ku, Osaka City -8 Do Building Seki Nishi Matek Co., Ltd.

Claims (7)

[Claims] 1. A crushed sand raw material supplied from a crushed sand raw material supply line is crushed and classified by a sand maker comprising a cage mill having a classification function, and a part of the crushed product is supplied as a cage mill raw material by a fixed ratio to supply the crushed sand raw material. Sand making method characterized by returning to the line. 2. A crushed sand raw material supplied from a crushed sand raw material supply line is crushed and classified by a sand maker comprising a cage mill having a classification function, and the crushed product is periodically and automatically sampled, and its particle size distribution is automatically adjusted. A sand-making method characterized by measuring and controlling the rotation speed of a cage mill so that the measurement result meets predetermined conditions. 3. A crushed sand raw material supplied from a crushed sand raw material supply line is crushed and classified by a sand maker comprising a cage mill having a classification function, and a part of the crushed product is supplied as a cage mill raw material by a fixed ratio to supply the crushed sand raw material. While returning to the line, the crushed product was periodically and automatically sampled, its particle size distribution was automatically measured, and the rotation number of the cage mill was controlled so that the measurement result matched predetermined setting conditions. Sand making method characterized by the above-mentioned. 4. A crushed sand raw material supply line including a conveying device,
A sand maker comprising a cage mill having a classification function of crushing and classifying the crushed sand raw material supplied from the crushed sand raw material supply line, a distribution device for distributing the crushed product from the sand maker at a predetermined distribution ratio, A product crushing sand production line connected to one of the distributing sides of the device, and a crushed sand raw material supply line connected to the other distributing side of the distributing device for distributing a part of the crushed product from the sand maker at a fixed rate. And a return means for returning the sand to the sand making apparatus. 5. A crushed sand raw material supply line including a conveying device,
A sand maker comprising a cage mill having a classifying function for crushing and classifying the crushed sand raw material supplied from the crushed sand raw material supply line, a product crushed sand production line connected to a crushed product take-out part of the sand maker, Particle size distribution measuring means for periodically and automatically sampling the crushed product in the crushed sand production line and automatically measuring the particle size distribution, and a cage mill so that the measurement result of the particle size distribution measuring means matches predetermined setting conditions. And a rotation control means for controlling the number of rotations of the sand. 6. A crushed sand raw material supply line including a transport device,
A sand making machine comprising a cage mill having a classifying function for crushing the crushed sand raw material supplied from the crushed sand raw material supply line, a distribution device for distributing crushed products from the sand maker at a predetermined distribution ratio, and a distribution device A product crushed sand production line connected to one of the distributing sides, and a part of the crushed product from the sand maker connected to the other distributing side of the distributing device is returned to the crushed sand raw material supply line by a fixed ratio. Returning means, a particle size distribution measuring means for periodically and automatically sampling the crushed product in the product crushed sand production line, and automatically measuring the particle size distribution, and a setting in which the measurement result of the particle size distribution measuring means is predetermined. A sand making device comprising: rotation control means for controlling the rotation speed of a cage mill so as to meet a condition. 7. The predetermined setting condition is based on a database determined by a relationship between a rotation speed of a sand maker and an FM value corresponding to the rotation speed.
3. The sand-making apparatus according to 1.