JPS6365379B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a classification device capable of continuously classifying and removing coarse particles from titanium oxide slurry.

Titanium oxide slurry is used when producing a titanium oxide-containing synthetic polymer. In particular, when the polymer is used as fiber, titanium oxide must be dispersed in fine particles. For this purpose, it is generally possible to produce a titanium oxide slurry containing only fine particles by classifying and removing coarse particles from a titanium oxide slurry that contains both coarse particles of several μm and fine particles of less than 1 μm. It is being done.

[Prior Art] As a classification device for titanium oxide slurry, a device is known in which a siphon tube is provided at the top of a classification tank having a certain space (Japanese Patent Publication No. 57-5582). This device classifies titanium oxide slurry by supplying a slurry stock solution from above, leaving it for a certain period of time, and then extracting a supernatant liquid containing only fine particles through a siphon tube.

[Problems to be Solved by the Invention] However, in this apparatus, the classification operation must be performed in a batch system, and therefore the fine particle slurry cannot be taken out continuously, resulting in low productivity.

Therefore, in order to continuously classify this titanium oxide slurry, we attempted to apply an inclined plate type sedimentation separator that performs continuous separation using a lamellar space having a large number of inclined plates.

However, this inclined plate type sedimentation separator is difficult to use, such as separating sand and decaying organic matter in sewage treatment.
It has been applied to sedimentation separation when the particle size and specific gravity of sediment are significantly different from other materials.
With conventional equipment structures, it has been difficult to classify and remove coarse particles from titanium oxide slurry.

Therefore, the present invention was developed as a result of intensive studies aimed at developing an inclined plate type classification device that can continuously classify and remove coarse particles from titanium oxide slurry. be.

[Means for Solving the Problems] In order to achieve this object, the titanium oxide slurry classification device according to the present invention includes a hopper 1 having a conical or pyramidal bottom surface, and a hopper 1 above the hopper. A classification tank 3 consisting of a lamellar space 2 in which a large number of parallel plates 8 are arranged at substantially constant intervals and inclined at a constant angle; a supply pipe 5 having an opening in the upper space 4 in the hopper; It consists of an extraction pipe 6 that opens downward at the bottom of the hopper; and a discharge pipe 7 that opens above the lamella space.

Hereinafter, the structure of the device, its operation, and effects will be explained with reference to FIGS. 1 and 2 showing an example of the device according to the present invention. Note that FIG. 1 is a partially cutaway side perspective view of the classification device.

The classification device according to the present invention basically consists of a classification tank 3 having a hopper 1 and a lamella space 2 placed in a continuous manner on the hopper, a supply pipe 5 attached to the upper part of the hopper, and a lower part of the hopper. an extraction pipe 6 attached to the lamellar space, and a discharge pipe 7 above the lamella space.
It consists of

Then, the titanium oxide slurry stock solution containing both fine particles and coarse particles is supplied through the supply pipe 5, classified by the lamella space 2, and the fine particle slurry from which the coarse particles have been removed is taken out from the discharge pipe 7. A coarse particle slurry containing coarse titanium oxide particles is taken out from the extraction pipe 6.

The hopper 1 has the function of storing a certain amount of titanium oxide slurry and sedimenting the coarse titanium oxide particles in the titanium oxide slurry. Therefore, it has a certain volume. As shown in Figure 1, the bottom surface may be pyramid-shaped, or may have other shapes,
For example, it may have a conical shape.

The lamellar space 2 is a space in which a large number of parallel, so-called layered plates 8 are arranged at approximately constant intervals and tilted at a constant angle. The angle of inclination may be between 30 and 85 degrees, preferably between 45 and 75 degrees. In the present invention, the hopper 1 and the lamella space 2 are collectively referred to as a classification tank 3. The supply pipe 5 is a pipe having an opening in the space 4 above the hopper. For example, as shown in FIG. 2, the opening preferably has a shape in which the titanium oxide slurry stock solution is distributed and supplied toward the bottom of the hopper (arrow). The position of the opening is preferably below the lower end of the plate 8 and as high as possible above the hopper 1.

The extraction pipe 6 is attached with its opening facing the bottom of the hopper. This is to discharge highly concentrated titanium oxide slurry containing coarse particles that are settling. Therefore, the shape of the bottom surface of the hopper and the method of attaching the extraction pipe are determined so as to enable discharge of the highly concentrated titanium oxide slurry containing coarse particles.

A discharge pipe 7 for taking out the titanium oxide fine particle slurry is provided above the lamella space 2. This discharge pipe 7 is provided to discharge from the lamella space 2 a low concentration titanium oxide slurry in which coarse particles have been sedimented and removed and only fine particles are left. Therefore, the mounting position of the discharge pipe and its opening are determined so that the low concentration titanium oxide fine particle slurry can be discharged.

[Effect] The device of the above structure operates as follows.

When a titanium oxide slurry stock solution containing coarse particles is continuously supplied to the hopper from the supply pipe 5, the titanium oxide slurry first accumulates in the hopper. If the slurry is still continuously supplied, the titanium oxide slurry will eventually overflow from the hopper and rise in the lamella space 2.

However, since the inclined plates 8 are arranged at regular intervals in the lamella space, the coarse particles in the rising titanium oxide slurry collide with the inclined lower surface of the plates 8, are swept downward, and settle. The rate of sedimentation and the rate of rise of the titanium oxide slurry balance to cause particle classification.

The degree of classification depends on the feed rate of the slurry and the cross-sectional area of the lamellar spaces as well as the angle of the inclined plates. For example, in the case of titanium oxide slurry, the angle is preferably 30 to 85 degrees.

As described above, it is important for the classification device according to the present invention to maintain a balance between the descending flow of the titanium oxide coarse particles and the upward flow of the titanium oxide fine particle slurry in the inclined lamella space.
When classifying titanium oxide slurry, for example, coarse particles of 1 μm or more are classified and removed from titanium oxide particles of several μm or less, so the width of the particle size is relatively narrow.
Furthermore, since the classification is performed on slurry in which the difference between the particles to be settled and removed is extremely small, the balance between the above-mentioned settling flow and upward flow depends on the influence of the liquid flow accompanying the supply and withdrawal of the liquid. It is easily disturbed.

Therefore, in the classification device according to the present invention, the supply pipe 5
is opened into the upper space of the hopper located below the lamella space, and the coarse particle slurry is taken out through an extraction pipe 6 which is opened facing downward at the bottom of the hopper, and the liquid is supplied and taken out. The aim was to suppress the negative effects associated with this.

[Effects of the Invention] With this device structure, it is possible to maintain a balance between the sedimentation flow of coarse titanium oxide particles and the upward flow of titanium oxide fine particle slurry in the lamellar space, and to effectively generate the flow. It became possible to classify and remove coarse particles continuously and with high precision, and it became possible to classify titanium oxide with high productivity.

[Example] Hereinafter, the effects of the apparatus of the present invention will be explained with reference to Examples.

Example The classification device has the structure shown in Fig. 1, and the hopper part 1 has a 1000 mm square pyramid shape (bottom inclination angle 60 degrees), and the lamella space 2 has a 1000 mm square pyramid shape with a 60 degree inclination. The device used was a square prism, in which nine plates 8 tilted at 60 degrees were inserted at 100 mm intervals. Then, coarse particles of 1 μm or more were
Aqueous slurry of titanium oxide containing 270 kg/HR was continuously supplied for 6 months.

The concentration of the supplied titanium oxide water slurry was 24.8% by weight, the concentration of the coarse particle slurry taken out from the lower discharge pipe 6 was 25.5% by weight, and the concentration of the fine particle slurry taken out from the upper discharge pipe 7 was 17.0% by weight. .

The titanium oxide particles in the slurry discharged from the upper discharge pipe were 0.9 μm or less, and the titanium oxide fine particle slurry was continuously obtained at 22.5 kg/HR.

Six months later, the inside of the equipment was inspected, but no titanium oxide deposits were found, and good operation continued.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway side perspective view showing an example of a classification device according to the present invention.
FIG. 2 is a side perspective view showing an example of the shape of the slurry supply pipe. Explanation of symbols, 1... hopper, 2... lamella space, 3... classification tank, 4... upper space of hopper, 5
... Slurry supply pipe, 6 ... Slurry extraction pipe, 7
...Slurry discharge pipe, 8...Layered plate.

Claims (1)

[Claims] 1 A hopper 1 whose bottom surface is conical or pyramid-shaped, and a lamellar space 2 formed by arranging a number of parallel plates 8 above the hopper at approximately constant intervals and tilted at a constant angle. A classification tank 3 consisting of; a supply pipe 5 having an opening in the upper space 4 in the hopper; a withdrawal pipe 6 opening downward at the bottom of the hopper; and an opening above the lamella space. A titanium oxide slurry classification device comprising a discharge pipe 7.