JPH03186358A - Method for grinding wallastonite - Google Patents

Abstract

PURPOSE:To grind a lumpy matrix into a fibrous state without destructing a fibrous crystal too much by sending a wallastonite raw material toward pins moving at high speed to ground the same by the collision with the pins. CONSTITUTION:A raw material charging chute 7 is connected to the center of an almost cylindrical casing 8 and a small rotary plate 10a is fixed to one shaft 9a and the first rotary pins 11 are fixed to the peripheral part of the rotary plate 10a at a definite interval to constitute the cage of the first example. A large rotary plate 10c is fixed to the other drive shaft 9b and second, fourth and sixth rotary pins 12, 14, 16 are fixed to the rotary plate 10c to constitute the second, fourth and sixth cages. The inner peripheral part of a doughnut- shaped rotary plate 10b is fixed to the first rotary pins 11 and the intermediate and outer peripheral parts thereof are fixed to third and fifth rotary pins 13, 15. The raw material ground up to a necessary size in a grinding process becomes a fibrous shape whose aspect ratio is large and is discharged while the fibrous state is kept.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a wollastonite crushing method.

Conventional technology Asbestos has extremely high heat resistance and ash resistance, has great heat and electrical insulation properties, and is resistant to chemicals. Because it has many advantages, asbestos has been used in a wide variety of ways. On the other hand, asbestos is extremely harmful. There have been reports of asbestos lung disease and lung cancer among workers who inhale asbestos dust at asbestos manufacturing factories. In recent years, recommendations have been made regarding the permissible concentration of asbestos dust in workplaces where asbestos is handled, and strict controls have been implemented.

Therefore, manufacturers that use asbestos are focusing on developing alternative materials that are asbestos-free.

Unfortunately, minerals with fibrous crystals are rare in nature. Asbestos was one of the rare examples of such minerals, but recently, wollastonite has attracted attention as an alternative mineral.
te). This mineral forms fibrous crystals and is produced as a cohesive, massive host rock.

Problems to be Solved by the Invention Although wollastonite is suitable as a material to replace asbestos, a major practical problem is that it is difficult to crush the massive host rock into fibers. The fibers were destroyed during crushing, making it difficult to obtain fibrous materials.

OBJECTS OF THE INVENTION An object of the present invention is to provide a wollastonite crushing method that can crush fibrous crystals from massive host rock into fibers without significantly destroying them.

SUMMARY OF THE INVENTION To achieve the above-mentioned objects, the present invention is based on a wollastonite crushing method according to claim 1.

Means for Solving the Problems The wollastonite raw material is sent toward a pin moving at high speed, and the wollastonite raw material is crushed into fibers by collision with the pin.

EXAMPLES Hereinafter, preferred examples of the present invention will be described with reference to the drawings, but the present invention is not limited thereto.

In its naturally occurring state, wollastonite is mixed with topsoil and other impurities. Therefore, many impurities adhere to the wollastonite raw material as it is mined.

In addition, large chunks of host rock are also mixed into the wollastonite raw material mined at the face.

Therefore, as shown in FIG. 1, impurities are removed as much as possible to increase the purity of the wollastonite raw material. Pretreatment is carried out before the wollastonite raw material is put into the final crushing process.

Raw rock of wollastonite (massive host rock) is placed in raw rock hopper 1
The soil is fed to a scalping type screen 3 by a feeder 2, where surface soil and other impurities fall downward, and the impurities are first discharged to a predetermined location by a conveyor 4. On the other hand, the raw wollastonite that has been sorted by the screen 3 enters a show crusher 5, where it is crushed secondarily, and further crushed secondarily by a cone crusher 6. This completes the pretreatment of the wollastonite raw material.

After that, final crushing is performed.

During final crushing, the size (width) of each crushed piece is 40μ.
It is preferable to set the thickness to 150μ. The key is to reduce the number of particles of 150μ or more and the number of particles of 40μ or less as much as possible. If the size is 150μ or more, the crystals will not be easily crushed, the aspect ratio will be small, and the crystal will not be fibrous.

When the size is smaller than 40μ, it loses its properties as a fiber. Even if the width is between 40 and 150μ, it is of little significance unless the overall shape is fibrous. As a criterion for this, it is preferable to set the aspect ratio to 100 to 300. The aspect ratio is expressed as the ratio of the length and width of each crushed piece.

An impact crusher using pins is optimal for crushing the wollastonite raw material to have the aspect ratio described above. A crusher that applies compressive force or shear force tends to over-crush the wollastonite raw material, resulting in the destruction of the fibers.

A rotary impact crusher is shown in FIGS. 2 and 3 as an optimal example. In this example, a raw material input chute 7 is connected to the center of a substantially cylindrical casing 8, and two drive shafts 9a, 9b are horizontally disposed therein.

These drive shafts 9a s 9b rotate in opposite directions. A small circular rotary plate 10a is fixed to one of the shafts 9a, and tenth tally bins 11 are fixed at regular intervals around the periphery of the rotating plate 10a, forming a first row of cages. A large circular rotary plate 10c is fixed to the other drive shaft 9b, and the 20th
- tally bin 12, 40th - tally bin 14 and 6th
0-tally pins 16 are fixed and constitute a second cage, a fourth cage, and a sixth cage, respectively.

The donut-shaped rotary plate 10b has an inner circumferential portion fixed to the tenth tally pin 11, and an intermediate portion and outer circumferential portion fixed to the 30th tally pin 13 and the 150th tally pin 15, respectively. Arrow 17 indicates the input direction of the raw material, and arrow 18 indicates the discharge direction of the crushed material.

The raw material collides with the 10th turbine 11 in a coarse state, and further collides with the 20th turbine 12 which rotates in the opposite direction to be crushed, and then passes through the 3rd and 40th turbines 13 and 14 in order to the 5th and 60th turbines. When reaching turbines 15 and 16, the debris becomes thinner and thinner.

In the crushing process, the pieces that are crushed to a required size while being crushed sequentially from the 10th turbine 11 have a large aspect ratio. In other words, it becomes fibrous. Such fibrous materials do not collide with the rotor turbines 11-16 due to the air flow generated by the rotation of the rotor turbines 11-16. Therefore, the fibers are discharged without being crushed by the rotor turbines 11 to 16 while maintaining the fiber state.

On the other hand, coarse crushed pieces (those with a small aspect ratio) are unaffected by the air flow because they have a large mass, and are continuously crushed by the impact from the rotor turbines 11 to 16. At this time, due to the characteristics of wollastonite, it is torn from the crystal plane and becomes fibrous.

According to the experimental results, in the case of the cage mill shown in Figs. 2 and 3, the optimum rotational speed of each rotor turbine 11 to 16 is as shown in Table 1.
It was as follows.

The spacing t between the rotor turbines of adjacent rows during rotation was 15I1 m. The cross-sectional shape of each rotor turbine is very good.

When the above conditions were repeated 2 to 3 times to crush the wollastonite raw material in the chute 7, the wollastonite raw material became fibrous crushed pieces having a desired aspect ratio in a state close to 100%.

The basic idea behind the crushing mechanism of an impact crusher is that it uses the air flow to prevent light fibrous items from colliding with the rotor turbine and therefore not receiving impact, and to crush heavy items. is crushed by being blown by a rotor turbine without being affected by air flow. It is not limited to rot turbines as long as such a crushing mechanism can be obtained. Furthermore, the bottle may be moved in any manner. The present invention is not limited to crushing using a cage mill, but can also be carried out using, for example, an attrition mill or other types of crushing.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining the pretreatment of wollastonite raw material, FIG. 2 is a schematic end view showing an example of a suitable apparatus for implementing the method of the present invention, and FIG. 3 is a diagram showing the X of FIG. - A schematic cross-sectional view along the X-ray. Rough hopper feeder screen conveyor show crusher cone crusher chute casing a, 9b... Drive shaft Q a, 10 bs

Claims (1)

[Claims] A wollastonite crushing method characterized by sending a wollastonite raw material toward a pin moving at high speed, and crushing the wollastonite raw material into fibers by colliding with the pin. .