JPH0346838Y2 - - Google Patents

Description

[Detailed explanation of the idea]

(Industrial Application Field) The present invention relates to a wet ball mill, and more particularly to a wet ball mill suitable for efficiently pulverizing coal and the like and mixing it with a liquid medium. (Conventional technology) In the case of an actual wet ball mill, there are 3 to 4 mills inside the mill.
It is divided into rooms and has a structure that prevents short passes. Each chamber was filled with balls of two to three different diameters, but the distribution ratio of balls of each diameter was the same in each chamber, and only the amount of balls filled was changed. (Problem to be solved by the invention) However, according to the inventors' study, the characteristics of the powder diameter distribution of the object to be crushed change with the passage of grinding time, and the distribution ratio of the conventional balls is not always sufficient. It was found that it was not crushed in a reasonable manner. FIG. 2 shows test results for a conventional small wet ball mill. The samples are Pacific coal and Horonai coal, and the medium liquid is anthracene oil. The breakdown of the ball is
Three types of balls: 25φ, 30φ, 40φ, 46%, 20%,
It is filled with a distribution ratio of 34%. From this test result, (1) coal has an initial 30 to 60
(2) After 90 minutes, the particle size of the coal remains almost the same and the grinding action is hardly performed. (3) The viscosity of the mixture increases as the particle size of the coal decreases. I found out. From the above, initial pulverization is effective, and a predetermined degree of pulverization can be obtained within the initial 30 to 60 minutes. However, it was found that after 90 minutes, although the viscosity of the mixture increased, it was disadvantageous for grinding and the effect was not improved. The purpose of the present invention is to provide a wet ball mill that can efficiently grind a material to be ground and mix it with a liquid medium based on the characteristics of the particle size change of the material to be ground, which changes with the passage of grinding time. It is in. (Means for solving the problem) The inside of the mill is divided into at least first, second, and third chambers, balls of different particle sizes are mixed and filled in each chamber, and the material to be crushed is crushed, In a wet ball mill that mixes with a medium liquid, the mixing ratio of balls in the first chamber is set such that small diameter balls with a diameter of 16 to 30 mm and large diameter balls with a diameter of more than 40 mm and 60 mm or less are respectively equal to the weight of the balls in the first chamber. 35-40%,
The remaining weight is medium-diameter balls with a diameter exceeding 30 mm and 40 mm, and the mixing ratio of the balls in the second chamber is such that the small-diameter and medium-diameter balls are each 35 to 40% of the weight of the chamber balls, and the remaining weight is The above-mentioned large-diameter balls are used, and the mixing ratio of the balls from the third chamber onward is
The above large diameter ball is 45 to 55% of the weight of the chamber ball,
A feature is that half of the remaining weight is made up of small and medium diameter balls. In this invention, a small diameter ball is defined as a ball with a diameter of 16 to 30 mm.
A medium-diameter ball refers to a ball with a diameter in the mm range.
This refers to balls with a diameter of more than 30 mm and less than 40 mm, and a large diameter ball refers to a ball with a diameter of more than 40 mm and less than 60 mm. In this invention, small diameter balls and large diameter balls are placed in the first chamber of the mill, each accounting for 35 to 40% of the weight of the balls in the first chamber.
By distributing the remaining weight to medium-diameter balls, initial pulverization (coarse pulverization) can be carried out efficiently, and small-diameter and medium-diameter balls are placed in the second chamber, each weighing 35 to 35% of the ball weight in the corresponding chamber. By distributing 40% of the weight and using large diameter balls for the remaining weight, the coarsely ground particles can be efficiently pulverized into fine particles. By distributing 45 to 55% of the weight and using small-diameter and medium-diameter balls as each half of the remaining weight, the material to be crushed and the medium are mainly mixed well. As a result, it is possible to grind the material to be ground in a short time and with less required power, and to mix it well with the liquid medium, even though the particle size of the material to be ground changes as the grinding time elapses. can. Hereinafter, the present invention will be explained in more detail with reference to embodiments shown in the drawings. (Example) FIG. 1 is an explanatory diagram showing an outline of an example of the present invention. The wet ball mill shown in FIG. 1 includes a supply means 1 for supplying a medium key such as anthracene oil for supplying a material to be crushed such as coal, a mill 2 that is rotationally driven in the direction of the arrow shown in the figure,
It is equipped with means 8 for crushing and taking out the mixture. In this embodiment, the inside of the mill 2 is divided into three chambers, ie, a first, second, and third chamber 4, 5, and 6, in the axial direction by a perforated plate 3. the first, second and third chambers 4;
5 and 6 are filled with a mixture of balls 7 of small diameter, medium diameter, and large diameter, and each chamber is filled with balls 7 of small diameter, medium diameter, and large diameter.
The distribution ratio of medium and large diameter balls is different. As the ball 7, balls of small diameter, medium diameter, and large diameter shown in Table 1 are used.

[Table] Table 2 shows the distribution ratio of small diameter, medium diameter and large diameter balls 7 in each chamber in the present invention. However, this distribution ratio is expressed as a weight ratio to the filling amount of each chamber.

[Table] In the wet ball mill configured as described above, the material to be crushed such as coal and a liquid medium such as anthracene oil are supplied into the mill 2 through the supply means, and the mill 2 is rotated. In the first chamber 4 of the mill 2, a large number of small and large diameter balls are distributed, and a small number of medium diameter balls are distributed, so that the material to be crushed is efficiently coarsely pulverized by the action of the balls 7 having this distribution ratio. The mixture of the pulverized material and the liquid medium is sent to the second chamber 5 through the perforated plate 3. Next, in the second chamber 5, a large number of small and medium diameter balls are distributed and a small number of large diameter balls are distributed, so that the pulverized material crushed in the first chamber 4 is is efficiently pulverized, and a mixture of the pulverized material and the liquid medium is sent to the third chamber 6 through the perforated plate 3. In the third chamber 6, approximately half of the large diameter balls and approximately one quarter of the small and medium diameter balls are distributed. and the medium liquid are actively mixed, and balls 7 are prevented from flying out of the mill 2. The mixture of the pulverized material and the liquid medium mixed in the third chamber 6 is taken out through the taking out means 8. In addition, in the present invention, the inside of the mill 2 may be divided into four or more chambers, and in this case, the distribution ratio of the balls 7 in the fourth and subsequent chambers is set to be approximately the same as that in the third chamber, so that the finely ground material and the medium liquid are divided. It can enhance the mixing function. Examples and Comparative Examples A ball mill with an inner diameter of 1300φ and a length of 3600 m/m was used to conduct a pulverization experiment on coal (Pacific Coal). The ball mill body is divided into three chambers, No. 1, No. 2, and No. 3, and each chamber is filled with balls of 1.5 tons, 0.1 tons, and 1.5 tons. The diameter of the balls to be filled is 50φ, 40φ,
There are three types of 30φ. In the conventional method (comparative example), the filling ratio of each ball diameter in each chamber was 50φ: 32wt%, 40φ: 26wt%,
30φ: 42wt%. On the other hand, in the embodiment of the present invention, the filling ratio of each ball diameter was set as shown in Table 3.

【table】 Table 4 shows the ball mill grinding operation results.

[Table] Total weight Looking at the particle size distribution in Table 4, it can be seen that the yield of 200 mesh or more was higher in the example at 87.17 wt%, indicating that it was pulverized more efficiently. Furthermore, in this example, the viscosity was about half that of the comparative example, although the degree of pulverization was high.
This greatly contributes to reducing the specifications of subsequent equipment and facilities. (Effects of the invention) According to the invention, the inside of the mill is divided into at least the first, second, and third chambers, and the ball distribution ratio in each chamber is set to a specific ratio. The object to be crushed can be efficiently pulverized in accordance with the change in the particle size of the pulverized object, and can be mixed well with the liquid medium.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an outline of an embodiment of the present invention, and FIG. 2 is a diagram showing test results of a small-sized wet ball mill. 1... Means for supplying the material to be crushed and the medium liquid, 2... Mill, 4, 5, 6... First chamber, second chamber, third chamber of the mill
Chamber, 7... Ball, 8... Means for taking out the mixture of the finely ground material and the liquid medium.

Claims (1)

[Scope of utility model registration request] In the wet ball mill, the inside of the mill is divided into at least first, second, and third chambers, and each chamber is filled with a mixture of balls having different particle sizes, and the material to be crushed is crushed and mixed with a medium liquid. The mixing ratio of balls in the first chamber is 35 to 40% of the weight of the balls in the first chamber, and small balls with a diameter of 16 to 30 mm and large balls with a diameter of more than 40 mm and less than 60 mm.
The remaining weight is medium-diameter balls with a diameter exceeding 30 mm and 40 mm, and the mixing ratio of the balls in the second chamber is such that the small-diameter and medium-diameter balls are each 35 to 40% of the weight of the chamber balls, and the remaining weight is The above-mentioned large-diameter balls are used, and the mixing ratio of the balls from the third chamber onward is
The above large diameter ball is 45 to 55% of the weight of the chamber ball,
A wet ball mill characterized in that half of the remaining weight is made into small diameter balls and medium diameter balls.