JPS6265756A - Wet classifying method for granular particle - Google Patents

Abstract

PURPOSE:To prevent the crushing of granular particles having weak strength and to increase treating capacity by supplying an aq. slurry to a vibrating screen arranged with bars formed to an inverted triangular shape at specified intervals then spraying water thereto. CONSTITUTION:This invention relates to a method for sieving the granular particles having a grain size distribution in the slurry state, in which plural pieces of the bar materials 1 formed to the approximately inverted triangular shape in the cross section are arranged at specified intervals to a plane shape to form the screen having the trapezoidal shape in the spaces between the respective bar materials when viewed from the longitudinal direction of the materials 1. The aq. slurry of the raw material granular particles is supplied to such screen and while the screen is vibrated, the water is uniformly sprayed to the granular particles from shower nozzles. Then the fluidity of the granular particles is satisfactorily maintained and the dispersibility thereof is improved. The crushing of the particles is prevented and the clogging arises hardly.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention involves sifting the grains in a slurry state (V) with particle size m, and separating one powder grain larger than the size of the sieve (this slurry and This invention relates to a method of separating into V) a granule slurry having a smaller particle size.

[Conventional technology and its problems] As a means of separating powder and granules into two or more 8Y types based on size or density, sieving using a mesh is a method of classification using the difference in sedimentation speed in the operation and fluid. operation is known. Of these, both dry and wet methods have the drawback that the sieves tend to become clogged. on the other hand,
In the classification operation, the method of using a sedimentation classifier is:
If the difference in density between the liquid (mainly water) that disperses and suspends the powder and the powder is small, the processing capacity per unit settling area is disadvantageous. In addition, the method of using a mechanical sorter or centrifugal sorter can only be classified as 1 for weak powder and granular materials. It has drawbacks such as the risk of it being crushed during production.

[Component (1'4) of the invention] The present invention uses a screen having a special coarse structure that does not easily cause clogging and is easy to remove even if clogging occurs when sieving the granular slurry (25). (2) A person who can process powder and granules with low strength without worrying about their crushing, and who has a high processing capacity per h1 unit surface (wet processing).

However, the present invention proposes a wet classification method for granules.
A vibrating sieve that uses a screen in which a plurality of bars whose cross section is in the shape of an inverted triangle are arranged at regular intervals, and trapezoidal gaps are formed between each bar when viewed from the longitudinal direction of the bars. , supplying an aqueous slurry of powder and granules having a grain size of 9 minutes,
Vibrate the screen! V) grain 1 on the screen
It is characterized by uniformly distributing water to the tree.

1 Screen (mesh surface) of the collapsing sieve used in the present invention
As shown in Fig. 1, a plurality of single cow timbers 1 whose cross sections are approximately in the shape of an inverted triangle are arranged in a flat 1n shape at regular intervals. When viewed from the direction (see white arrow in FIG. 1), the gap between each bar has a trapezoidal shape. For the present invention, it is extremely important that the screen has a trapezoidal shape as shown in Fig. It is difficult to cause clogging, and even if it does become clogged, it can be easily cleared by backwashing, for example.

The cross section of 1 does not have to be an inverted triangle in the strict sense; for example, as shown in Figure 2 (,'l) or <b), the cross section of the rod as a whole can be considered to be an inverted triangle. The material can be used as a screen forming member of the present invention. When a plurality of rods are laid out in a plane, the spacing between the rods (2971~width) is arbitrarily selected according to the grain size of the slurry powder with classification U. Ru.

Figure 3: A screen like the one shown in Figure 1 is installed and two fetal movement sieves of the present invention are connected in series. 1 is a flowchart for classifying, in this embodiment, the first vibrating sieve 1
1 slurry 1-width 1. Amm screen 12 and a screen 12 with a slit width of 1.0 m are installed on the second vibrating sieve 21, respectively.

The aqueous slurry of the raw granules to be classified is first supplied to the screen 12 of the first oscillating sieve IXIN, and water is uniformly applied to the granules on the screen 12 from the shower nozzle 13. It will be ri. Shaking φ force sieve 1ji1
As a result of the 1st hand force sensing mechanism 17 forcing the 1st part to pass through the 1st part at any time, the screen 1st part 12 also vibrates, and the powder and granules are uniformly dispersed on the screen and sieved by the 1st part.

In this case, since water is supplied to the field from the shower nozzle 13 onto the screen 12, agglomeration of particles is prevented, and the powder and granules are sieved by the screen 12 while always maintaining a good dispersion state. In this way, the particles larger than the width +2) are passed through the sieve non-discharge port 19 together with water in slurry form into the slurry 1 of the screen 12) IS! be done. On the other hand, after passing through the screen 12, the powder and granules are taken out along with water from the sieve non-discharge port 18, and fed to the screen 15 of the second single-stage sieve 21.

The powder and granular material supplied onto the screen 15 is
As in the case above 2, water is replenished from the shower nozzle 13°, and the water is uniformly dispersed on the screen 15 and sieved by the vibration from the 17° shower nozzle. Then, the slurry 1 on the screen 15 has a width of 1.0 mm (width 1.0 mm): large powder and granules (sifted with water)
) is collected in the form of a slurry, while the grains having a particle size of 1.0 mm or less that have passed through the screen 15 are collected in the form of a slurry through the sieve non-discharge port 18°.

As mentioned above, the screen of the present invention, which is made up of a plurality of rods (A) whose cross sections are approximately triangular in shape and arranged in a plane at regular intervals, is designed to reduce the gap between each rod from the longitudinal direction of the rods. Since the screen is trapezoidal, there is significantly less clogging compared to conventional sieve mesh surfaces, but if clogging still occurs and the efficiency of the sieve decreases, each screen should be removed as shown in Figure 3. Particles caught in the slurry can be removed by backwashing the screen with water from the backwashing shower nozzle 14.14'. If the fluidity of the powder flowing out to the +11 outlet 19 or 19゜ on the sieve is insufficient, water can be added from the strainer nozzle 16 or (416°) to make the flow of the powder smoother. .

Shower nozzle +3. Screen from 13° +2. i
', +J2 The mother of water sprayed on each screen is l
It is possible to adjust the solid content moisture content of the slurry to be fed, the width of the slurry 1 to I of the screen, etc. If the amount of sprayed water is too large, water will accumulate on the screen and a part of the powder that would normally pass through the screen will flow out to the sieve 1 outlet, resulting in a decrease in classification efficiency. Furthermore, if the amount of sprayed water m is too small, the dispersion and fluidization of the powder and granules on the screen will be insufficient. Therefore, the amount of sprayed water depends on the solid content concentration of the slurry supplied onto the screen, the supply rate,
It is preferable to adjust the slit width of the screen so that a λ9 water film is formed on the screen and the powder and granules are maintained in an appropriate fluidity and dispersion state.

Figure 4 shows two vibrating sieve machines 11A3J shown in Figure 3.
:'Cf21 integrated, slurry l-Ill L4n
+m screen on top side, slit +, om+
This is an explanatory diagram of a vibrating sieve device in which a screen 1!1 of n is provided on the lower stage side, and in this way, two or more screens of the present invention with different slit widths can be incorporated into a single vibrating sieve. , the method of the invention can be carried out. In this case, it goes without saying that the screen on the upper stage side has a larger slit width. [Effects] The effects of the present invention are listed as follows.

(1) By dispersing water on the screen, water is always present on the screen, so the fluidity of the powder and granules is maintained well, and agglomeration of particles is prevented, resulting in improved dispersion. gets better.

(2) Since the surface of the particles is protected by a water film, the particles on the sieve can be prevented from colliding with each other during operation or being crushed due to friction or collision with the wall surface.

G) Due to the use of a screen with specially structured slits, the frequency of screen clogging is significantly reduced.
Furthermore, if clogging occurs, it can be easily cleared by backwashing.

Example 1 As shown in Fig. 4, slurry 1 in the upper stage - width 1.4+++m
Spherical silica with a solid content concentration of 65.7 wt% was screened using a photographic sieving machine equipped with a slit medium L Omm screen on the lower stage (the effective screen area for both the upper and lower stages is 1802πmm2). The hydrogel slurry was classified.

In addition, the particle size distribution when the raw material slurry was dried at 150° C. and classified using a JIS standard sieve was as follows.

-0.84mm 49.3wt%0.
84~1.00mm 10.2Il+, OO~
L4+mm 21.5++141~1.68m
m εQ n1,000L 68mm
11. In experiment (A), the supply m of raw material slurry was set to 15 Ka/min, and 17 shear nozzles of 5 trees were installed above each screen. In (B), the same 6
The classification operation was carried out at 9/min for 11 minutes, and the raw material slurry was divided into three parts: slurry on the upper screen sieve, slurry on the lower screen sieve, and slurry under the lower screen sieve. Rimples for particle size distribution measurement were collected from each slurry thus classified, and after drying at 140 to 150°C, the particle size distribution of each was measured using a JIS standard 1% t sieve. The results are shown in Tables 1 and 2.

Table 1: Experiment (A) - Spray water ff18.8.0/min 2nd
Table: Experiment (B) - 6.0/min 1.0-1.4m for spray water
11 items pumping efficiency - 2,9015,60X100=51
．． 8% Example 2 The two vibrating sieves used in Example 1 were connected in series as shown in FIG. [! Example 1
The same raw material slurry was classified.

However, the raw slurry supply m to the upper screen of the first photographing sieve was set to +5KO/min, and the water usage to be sprayed to each screen of both sieves was set to 6N/min.

Example 1 The upper screen sieve upper slurry, the lower screen sieve upper slurry, the lower screen sieve upper slurry, and the lower screen sieve lower slurry were collected from the second vibrating sieve, and the particle size distribution of particles contained in each slurry was determined. It was measured using the Aγ method in the same manner as above. 3rd result
Shown in the table.

(Margin below) Table 3

[Brief explanation of drawings]

Figure 1 is a perspective view of the screen used in the present invention, Figure 2 is a perspective view of the screen used in the present invention;
Figures (al and ri) are cross-sectional views of rods that can be used as constituent members of the screen used in the present invention. Figure 3 is a flow diagram showing one embodiment of the method of the present invention;
FIG. 4 is an explanatory diagram of the vibrating sieve machine used in Example 1, and FIG. 5 is an explanatory diagram of the flow adopted in Example 2. 1.(绝祠11.1st movement sieve 12.
Screen 13.13', shower nozzle +4.
+4°, backwash shower nozzle 15. screen i6
1G', shower nozzle 47.47'; vibration mechanism 1
8, 18°, sieve upper discharge port 19, 19': sieve 1 discharge port 21, 2nd vibrating sieve machine Patent applicant Catalysts & Chemicals Co., Ltd. Representative Patent attorney Shigeru Tsukimura Soto1fi1Makamo2V (al (t )
1E mouth “1 day 9 mins! 5 rods out”

Claims (1)

[Claims] 1. A vibration device having a screen in which a plurality of rods having an approximately inverted triangular cross section are arranged in a plane at regular intervals, and a trapezoidal gap is formed between each rod when viewed from the longitudinal direction of the rods. A wet classification method for powder and granules, which is characterized by supplying an aqueous slurry of powder and granules having a particle size distribution to a sieve, and uniformly distributing water to the powder and granules on the screen while vibrating the screen.