JPH0554361B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a crystallizer equipped with a filtration mechanism.

[Conventional technology]

Generally, the process of producing crystals as a product often requires reaction, crystallization, and filtration operations, but these crystallization operations and filtration operations are usually performed in separate dedicated devices. in this case,
Not only does the construction cost of the equipment increase, but the slurry that has undergone crystallization must be transferred to the next processing facility, which reduces yield and increases operational effort.

As a first example, the crystals crystallized by the crystallization operation are extracted from the crystallization tank using a slurry pump, concentrated using a concentration tank or a liquid cyclone, etc., and then centrifuged.
Alternatively, as a second example, the crystallization tank is installed in a high position, a slurry extraction valve is provided at the bottom of the crystallization tank, and the crystals are fed to the centrifuge and the filter using a head difference. There is a method of supplying and separating.

However, in the first example, the mechanical crushing of the crystals by the impeller of the slurry pump was extremely large;
It is difficult to obtain crystals with large grain sizes. In the second example, there is no problem with crystal crushing, but equipment costs increase, such as the need for pumps and tanks to return the crystal separation mother liquor, and the slurry supply line is likely to be clogged, making maintenance management difficult. This requires a lot of effort.

Instead of this type of splitting device system, there are also systems in which reaction, crystallization, and filtration operations are performed in the same tank. In this case, the continuous system is such that the crystals are discharged using a screw conveyor installed at an angle at the bottom of the crystallization tank. In addition, in the batch method, a filter plate and stirring blades are arranged in a cylindrical tank that can be rotated around a horizontal axis.In the case of crystallization operation, the filter plate is positioned above, and in the case of over-operation, the tank is closed. It is used by rotating it 180 degrees.

[Problem that the invention seeks to solve]

However, with the above connection method, there is a limit to the inclination angle of the screw conveyor, and the crystal outlet must be located above the liquid level of the crystallization tank.
Since the screw conveyor requires a large (long) installation space, it is difficult to adjust the dehydration and dewatering times, resulting in poor dewatering efficiency, inability to clean the cake, and maintenance of the screw conveyor's shaft seal. There are problems such as it is time consuming.

Additionally, batch systems inherently do not allow for continuous supply of raw materials and discharge of products. Furthermore, since the tank is rotated when transitioning from crystallization operation to over-operation, the height of the entire apparatus becomes high and workability is poor. Furthermore, since the tank is subjected to an eccentric load when it rotates, there are many structural problems, and there is a limit to increasing the size of the tank.

Therefore, the main purpose of the present invention is to not only enable reaction, crystallization and filtration to be carried out in the same tank, but also to
An object of the present invention is to provide a crystallizer that has excellent operability and low equipment cost.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention provides an apparatus for performing crystallization by providing a stirring mechanism in a tank to generate a liquid flow in the liquid in the tank, and in which crystals can be accommodated in the flow of the liquid. A liquid is provided, and the overbody is configured to be movable between the liquid and the discharge section above the liquid.

[Effect]

According to the present invention, since the overbody 15 is disposed in the liquid in the tank 1, crystals are accumulated in the overbody 15 as the slurry liquid is fluidized. Once a certain amount of crystals have accumulated, the crystals can be discharged by raising the overbody 15 above the liquid and overturning it.

If the overbody is formed by a screen cage, for example, and the means for raising and lowering it is, for example, a winch method, an extremely simple device will be sufficient, and by periodically discharging the crystals, it will be possible to continuously Able to drive.

[Specific examples of the invention]

The present invention will be explained in more detail below with reference to specific examples shown in the drawings.

1 is a cylindrical crystallization tank with a bottom, and a support leg 3 is placed on a base 2.
It is erected through the Inside the tank 1, a draft tube 4 as an inner cylinder is held with its lower end floating by four supports 5A at the upper part and four supports 5B between it and the cone 6 at the lower part. Three stirring blades 8 rotated by a rotary drive motor 7 are arranged within the draft tube 4 . Draft tube 4 is a refrigerant (or heat medium)
It is cooled by the refrigerant supplied from the supply port 9A. 9B is a refrigerant outlet.

Further, a cooling jacket 10 is provided around the outer periphery of the tank 1, and the refrigerant also flows through this jacket from a refrigerant supply port 11A toward a refrigerant outlet 11B. In this way, the stock solution is cooled by the cooling heat provided from the draft tube 4 and the cooling jacket 10, and crystals precipitate and float in the solution, forming a slurry.
This crystal slurry becomes a circulating flow in the direction of the arrow in FIG. 1 under the stirring force of the stirring blade 8.

This circulating flow direction was chosen to make it easier to obtain clarified liquid within the clarified area 13 partitioned by the partition plate 12. If clarified liquid is not required, it is better to use the opposite direction as described below. This is advantageous because the crystals can be easily trapped in the body. 14 is a clear liquid outlet.

On the other hand, a rigid moving guide means is disposed in a part of the annular area between the inner wall surface of the tank 1 and the draft tube 4, and the overbody 15 can be moved up and down using this as a guide. The overbody 15 is made of wire screen, for example, and is a box with an upper opening and a bottom. On the left side of the overbody 15 in the drawing, there is a groove-shaped guide body 16A that basically guides the left side surface of the overbody 15.
is erected, and channel-shaped guide rails 16 are provided on the right side of the overbody 15 and at the front and back in the direction penetrating the page.
B is also erected with its grooves facing each other. An inverted U-shaped arm 17 is pivotally attached at both ends to the front and back points of the lower left side of the overbody 15 in a direction perpendicular to the plane of the drawing. In addition, at the upper right side of the tank 1, there are two coaxial drums 19 driven by a hoisting motor 18,
19 are arranged, and these and the arm 17 are connected by a wire rope 20. Furthermore, in each groove of each guide rail 16B, 16B,
Guide rods 21 attached to both sides of the upper part of the overbody 15 in the front and back direction are engaged. Guide rail 16B
The upper part thereof is inclined diagonally upward, and the end thereof forms an inverted part 16a closed like a bag.

A discharge chute 22 is formed facing the opening when the overbody 15 is reversed. 23 is a reversal stopper for the overbody 15. Further, a cake cleaning nozzle 24 is disposed in a direction toward the overbody 15 when the overbody 15 rises above the liquid.

In the crystallizer constructed in this manner, the overbody 15 is at the lower limit position of the guide means during reaction and crystallization.
On the other hand, when the slurry liquid is circulated in the direction of the arrow in FIG. and enters the body 15. When the crystals have accumulated to a certain extent, the hoisting motor 18 is activated and the overbody 15 is pulled up along the guide body 16A and the guide rails 16B, 16B via the wire rope 20. After that, when the excess body 15 appears on the slurry liquid,
The overbody 15 is temporarily stopped and the liquid in the cake is removed. In this position, if necessary, the cleaning nozzle 24
Washing water is sprayed toward the cake inside the overbody 15 to perform washing. When the liquid removal and water removal are completed, the overbody 15 is rolled up again, and the guide rod 21 abuts against the reversing portion 16a of the lifting limit.
Furthermore, when the overbody 15 is rolled up, the guide rod 2
1 as a fulcrum, the buttocks of the overbody 15 are lifted and reversed. As a result, the crystals (cake) in the bulk body 15 are discharged to the outside of the tank 1 via the discharge chute 22. In this case, if the overbody 15 is brought into strong contact with the stopper 23 during reversal, the impact will smoothly discharge the crystals.

When the drum 19 is rewound, the overbody 15 which has discharged the crystals is reversed and lowered to its lower limit according to its own weight, and the crystals are collected again.
This cycle is repeated continuously.

Here, the crystal sampling position and the deliquing/washing position of the overbody 15 can be freely selected by using a proximity switch or the like. In addition, the sampling time etc. can be changed freely by setting a timer, and the properties of the crystal can be changed.
It is set optimally depending on the properties of the mother liquor, operating load, etc.

On the other hand, as mentioned above, the circulation flow direction can be reversed as shown in FIG. Excellent capture ability.

By the way, in the present invention, as a material, as long as the crystal content can be captured while passing through the liquid,
Although it may be flat, a box-like shape is preferred in order to increase the amount of capture per time.
The material of the overbody may be made of cloth or the like.

The means for raising and lowering the overbody may not be a winch method, but may be a method along the screw axis or using a cylinder. Variations of the movement guide means will readily occur. Furthermore, in order to discharge the crystals in the overbody, it is also possible to discharge them through a separate grasping means, but a method of inverting the overbody is structurally simpler and more reliable.

〔Example〕

An example in which crystallization was performed using the crystallizer shown in the drawings will be shown below.

The specifications and operating conditions of the device are as follows.

○ Tank diameter: 1250 mmφ, tank height: 1900 mm ○ Stirring blade rotation speed: 85 rpm ○ Overbody: Screen cage with slit width 0.1 mm, capacity 9 liters ○ Handled substances: Copper sulfate and other mixed liquid ○ Crystal specific gravity: 2.3, mother liquor specific gravity 1.3 ○ Crystallization temperature: 15℃ ○ Overbody rising speed: 1 m/min ○ Deliquing time: 30 seconds As a result of operating under the above conditions, the internal slurry was uniform and mixed, and was of good quality with an average particle size of 0.5 mm. crystals were obtained. Also, crystal sampling,
The dewatering and filtration equipment continued to operate smoothly, and the average crystal adhesion moisture was 30 wt%, and there were no problems with crystal discharge or handling.

〔Effect of the invention〕

As described above, according to the present invention, the overbody for trapping crystals is provided in the flow of the liquid, and this overbody is movable between the inside of the liquid and the top of the liquid, so that the following effects are achieved.

(1) The crystallization and filter parts are integrated into one device, so the installation area is small.

(2) There is no need to use a slurry extraction pump, and only the operations of collecting, capturing and discharging the crystals are sufficient.
There is no mechanical crushing of the crystals, and operation with very brittle and fragile crystals is also possible.

(3) Since there is no slurry transfer, there are no line blockage problems.

(4) The equipment is simple, making it easy to operate.
Moreover, equipment costs are low.

(5) Even if the amount of precipitated crystals is small, it is still cost-effective.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of one embodiment of the apparatus of the present invention, FIG. 2 is a plan view, and FIG. 3 is a view taken along the - line. 1... Crystallization tank, 4... Draft tube (inner cylinder), 8... Stirring blade, 9A, 11A... Refrigerant supply port, 10... Cooling jacket, 13... Clarified liquid, 15... Superbody, 16A... Guide body, 16B
... Guide rail, 16a ... Reversing section, 18 ...
Hoisting motor, 20... Wire rope, 21...
...Guide rod.

Claims (1)

[Scope of Claims] 1. A device for performing crystallization by providing a stirring mechanism in a tank to generate a liquid flow in the liquid in the tank, wherein an overbody capable of accommodating crystals is provided in the flow of the liquid. , A crystallizer characterized in that the superorganism can be freely moved between the liquid and the discharge section above the liquid. 2. The overbody has a lower limit of descent in the lower part of the annular area between the inner cylinder arranged in the tank and the tank wall in claim 1.
Crystallizer described in section. 3 The body is box-shaped with an upper opening.
and is guided by a moving guide means extending vertically between the liquid surface and the liquid surface, and an inverted part is formed in the liquid upper part of the guide means, in which the overbody lifts the butt and the opening faces downward. A crystallizer according to claim 1.