JPH03215631A - Disintegrating method for dehydrated cake of filter press - Google Patents

Abstract

PURPOSE:To form dehydrated cake to finer and to adjusts its moisture in such a manner that the dehydrated cake can be utilized for sintering by adding dry dust to the dehydrated cake after primary disintegration and subjecting this cake to secondary disintegration, thereby simultaneously executing uniform mixing and disintegrating to fine grains. CONSTITUTION:The slurry in a storage tank 1 is dehydrated to about 20% moisture content by a filter press 2 and is transferred to a coarse disintegrator 3. The dehydrated cake subjected to the coarse disintegrating is sent to a primary disintegrator 5 by which the cake is primarily disintegrated. The dry dust 4 is fed by a rotary valve 6 and is dropped onto the dehydrated cake subjected to the primary disintegrating and is sent to a secondary disintegrator 7. The dehydrated cake after the primary disintegrating and the dropped dry dust 4 are simultaneously mixed and finely disintegrated by the secondary disintegrator 7. The mixture is sent to a hopper 9. The dust is mixed in the form of sticking to the surface of the dehydrated cake 8 at the time when the dehydrated cake 8 is finely disintegrated and, therefore, the sticking to the interior of the machine does not arise. The mixing ratio of the dehydrated cake 8 and the dry dust 4 is preferably 10:5 to 10:7.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides a method for crushing a dehydrated cake suitable for turning slurry generated in a steel mill into a cake with moisture and particle size that can be effectively used in sintering. It is related to.

(Prior technology) A filter press is usually used to dewater slurry generated in steel plants, but this dehydrated cake still contains about 20% water, so it is not possible to remove water as is. Under this condition, there are problems such as handling and hopper clogging. Therefore, it is necessary to mix dry dust into this dehydrated cake to adjust the moisture content.

Moreover, since this moisture-adjusted dehydrated cake has only been coarsely crushed, it has a large proportion of coarse particles (90% of which have a particle size of 10 lml or more), and cannot be used as it is for sintering. Therefore, after mixing with the dry dust, it is crushed into fine particles.

(Problem to be Solved by the Invention) By the way, as a means for uniformly mixing the dehydrated cake and dry dust, it is common to use a mixer such as a pug mill or a mixer. Since the moisture contained in the dehydrated cake compressed by the filter leaks to the surface, there is a problem that the dehydrated cake easily adheres to the blades and shafts, making it impossible to mix uniformly. If uniform mixing is no longer possible, there will be parts where the moisture content remains as high as about 20%, causing the following problems.

In other words, a crusher that uses a high-speed rotating blade and a fixed blade to shear the particles is generally used as a means of reducing the size of the particles.
As mentioned above, it is difficult to reduce the part containing about 20% water into fine particles using a crusher.

An object of the present invention is to provide a method capable of solving the problems of conventional crushing methods as described above.

(Means for Solving the Problems) In order to achieve the above object, the present invention dehydrates the slurry with a filter press, then roughly crushes and primary crushes the dehydrated cake, and then crushes the dehydrated cake after crushing. After adding dry dust, these dehydrated cakes and dry dust are simultaneously mixed uniformly and finely crushed in a secondary crusher, and the mixing ratio of the dehydrated cake and dry dust is 10:5 to 10:5. 1
Dry dust is added so that the ratio is 0:7.

According to the method of the present invention, primary crushing is possible even if the moisture content of the dehydrated cake is about 20%. This is because, unlike a mixer, a crusher uses high-speed shear to refine the particles, and even if some coarse particles remain, they will be sufficiently refined in the next secondary crusher.

Also, the mixing of the dehydrated cake and dry dust after the primary crushing,
By using a secondary crusher, when the dehydrated cake is pulverized, it is mixed in such a way that dry dust adheres to the surface of the dehydrated cake, so it does not adhere to the inside of the crusher and can be mixed uniformly. .

Although there is no difference in the gap between the crushing teeth between the primary crusher and the secondary crusher, finer particles can be obtained by crushing in two stages as in the present invention. However, in the case of only a dehydrated cake with a moisture content of about 20%, it cannot be made into fine particles even if it is crushed in two stages. Therefore, in the present invention, the moisture content is reduced by mixing it with dry dust in a secondary crusher. The grain size is reduced and refined.

In the present invention, the mixing ratio of dehydrated cake and dry dust is set to 10:5 to 10:7 because the water content after mixing is 11%.
This is because if it is less than 16%, dust will be generated, and if it is more than 16%, it will adhere to the conveying device, etc.

(Example) The method of the present invention will be explained below based on an example shown in the attached drawings. In the drawing, 1 is a storage tank for slurry generated at a steelworks. The slurry in this storage tank 1 is dehydrated in a filter press 2 to a water content of about 20%, and then sent to a coarse crusher 3, where it is coarsely crushed. It is disintegrated.

The coarsely crushed dehydrated cake is then sent to a primary crusher 5 for good mixing with the dry dust 4, where it is primarily crushed. Thereafter, the dry dust 4 is cut out and adjusted with the rotary valve 6 so that the mixing ratio is 10:5 to 10:7 according to the amount of the primary crushed dehydrated cake, and then the dry dust 4 is adjusted on the primary crushed dehydrated cake. and sent to the secondary crusher 7 in this state. In the secondary crusher 7, the dehydrated cake 8 after the primary crushing and the dry dust 4 dropped thereon are simultaneously mixed and pulverized and sent to a hopper 9. In this secondary crusher 7, when the dehydrated cake 8 is pulverized, it is mixed in such a way that the dry dust 4 adheres to the surface of the dehydrated cake 8.
No adhesion to the interior of the aircraft.

Next, the results of actually crushing a filter press dehydrated cake using the method of the present invention will be explained.

The main components and moisture content of the dehydrated cake and dry dust used are as shown in Table 1 below.

Table 1 (Unit: 2%) The dehydrated cake having the components and water content shown in Table 1 above was roughly crushed and then primary crushed. The particle size distribution after coarse crushing is shown in Table 2 below, and the particle size distribution after primary crushing is shown in Table 3 below.

Table 2 (Unit: 2%) Table 3 (Unit: 2%) Particle size distribution when the dehydrated cake that has been primarily crushed to the particle size shown in Table 3 above is subjected to secondary crushing by changing the mixing ratio of dry dust. The moisture content is shown in Table 4 below.

As is clear from Table 4 above, the particle size distribution of the dehydrated cake crushed by the method of the present invention satisfies the sintering acceptance standard of particle diameters of 10 m or more and 10% or less.

Regarding the moisture content, it is natural that the moisture content will decrease as the dry dust addition rate increases, but for handling reasons and to prevent hopper clogging, we
By adding dry dust at a ratio of 5 to 7, the moisture content (11 to 16%) that can be used for sintering can be achieved.

In addition, as a result of using the dehydrated cake and dry dust with the ingredients and moisture content shown in Table 1 above using a conventional method using a mixer and a crusher, the mixture was uneven and there were parts with a moisture content of 23%, which resulted in the crushing. This made it difficult to use for sintering.

(Effects of the Invention) As explained above, according to the method of the present invention, a filter press dehydrated cake can be made into fine particles and its water content can be adjusted so that it can be used for sintering.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the method of the present invention, where (a) is a schematic overall diagram;
(opening) is a detailed diagram of its main parts. 2 is a filter press, 3 is a coarse crusher, 4 is a dry dust, 5 is a primary crusher, 6 is a rotary valve, 7 is a secondary crusher, 8 is a dehydrated cake.

Claims (2)

[Claims] (1) After dewatering the slurry with a filter press, this dehydrated cake is roughly crushed and primary crushed, and then dry dust is added to the dehydrated cake after crushing, and then these dehydrated cakes,
A method for crushing a filter press dewatered cake, which is characterized by uniformly mixing dry dust and crushing it into fine particles at the same time using a secondary crusher. (2) The mixing ratio of dehydrated cake and dry dust is 10:5~
2. The method for crushing a filter press dehydrated cake according to claim 1, wherein the dry dust is added in a ratio of 10:7.