JPH05140885A - Flotation separator - Google Patents

Abstract

PURPOSE:To effectively carry out the flotation separation by lifting air fed from an air inlet through a clearance between an inner cylinder and an intermediate cylinder, reversing the course of the air in the upper part, lowering the resultant air through a clearance between the intermediate cylinder and an outer cylinder and releasing the air from the lower edge of the outer cylinder. CONSTITUTION:The objective flotation separator is equipped with a bubble producer 31 for feeding air (B) from an air inlet 46, communicating with a clearance between an inner cylinder 33 and an intermediate cylinder 34 and provided in the lower part of the clearance, lifting the air through the clearance between the inner cylinder and the intermediate cylinder, reversing the course of the air in the upper part, then lowering the air through a clearance between the intermediate cylinder and an outer cylinder 42 and releasing the air from the lower edge of the outer cylinder. Thereby, fine particles such as an ink in a raw material fluid (A) can effectively be removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flotation separation device used in a process of removing ink from waste paper.

[0002]

2. Description of the Related Art FIG. 8 is a perspective view of a first example of a conventional flotation separator used to remove ink from waste paper. In the figure, 1 is a hollow body, 2 is an air injection part of the same body, 3 is a mixing part of the same body, 4 is a floating separation part, and 5 is a discharge part. Reference numeral 6 is a raw material fluid inlet provided at one end of the main body, 7 is a compressed air inlet provided in the air injecting section 2, 8 is an outlet for a separated material containing ink or the like, and 9 is a residue after the separated material is removed. Is the outlet of the receptor.
The raw material fluid supplied from the raw material fluid inlet 6 is a fluid in which used paper is mixed and dissolved in a solution of a certain kind of chemical at a concentration of about 1%. Further, arrow A is a raw material fluid, B is compressed air, C is a separated discharge, and D is a receiver.

FIG. 9 is a divided perspective view of the air injecting section 2 of the above-mentioned flotation device. In the figure, 10 is a plurality of air nozzles connected to the compressed air inlet 7 and provided around the air injection portion, and 11 is an air chamber provided around the flow path. Compressed air is blown from this air nozzle 10 to form a donut-shaped air chamber around the flow path through which the raw material fluid flows. The supply air is dissolved in the raw material fluid under pressure, and bubbles are generated by the mechanical shearing action of the raw material flow on the air chamber.

FIG. 10 is a cross-sectional view of the mixing section 3 of the flotation device. In the figure, reference numeral 12 designates a plurality of stages of enlarged and rapid compression channels provided in this portion. The arrow E in the figure is a mixed flow of the raw material fluid and air, and the portion F is a minute turbulent flow caused by the expansion and contraction of the flow path. In this flow path, the mixed flow E
Due to a cavitation effect due to a sudden change in pressure in the expansion flow path, dissolved air in the raw material fluid is deposited as a large number of fine bubbles on the surface of the ink particles that have been hydrophobically modified. Next, the acceleration / deceleration flow and the minute turbulence F
By the action of, bubbles of various sizes including fine bubbles and ink particles collide and adhere.

The raw material fluid / air mixture E exiting the mixing section 3 enters the separating and floating portion 4 of FIG. 8, and the bubbles with ink particles rise toward the interface, causing bubbles containing ink on the liquid surface, that is, floss. To form. At this time, by controlling the flow pattern of the raw material fluid in the separation floating part 4 and maintaining an appropriate turbulent flow, it is possible to control the mixing of the fibers in the waste paper into the floss and also to prevent the precipitation of the fibers. Prevent and improve fiber yield.

After the process, the raw material fluid moves to the discharge section 5, and the froth on the interface containing the ink is discharged from the separated matter discharge port 8 as the separated discharge C, and the remaining ink is removed. The fibrous fluid is sent to the next step from the receptor outlet 9 as the receptor D.

FIG. 11 is a perspective view of a second example of a flotation device used for the same purpose as the first example. In the figure, 21 is a box-shaped main body, 22 is a raw material fluid inlet, 23 is an air intake, 24 is a separated product outlet, 25 is a receiver outlet,
Reference numeral 26 is a turbine, and 27 is a turbine driving motor.
In addition, arrow A is a raw material fluid, B is air, C is a separated discharge or floss, and D is a receiver.

In this apparatus, the used paper raw material present in the solution at a concentration of about 1% is supplied to the raw material fluid inlet 22 and stays in the flotation / separation apparatus main body 21 and then the receptor outlet 24.
Sent to the next step. At that time, the air intake 23
The air sucked from the turbine is sheared by the turbine 26 rotated by the turbine driving motor 27,
It becomes small bubbles, coalesces with ink to generate floss, floats on the liquid surface, and is discharged from the separated discharge outlet.

[0009]

In recent years, it has become popular to aim to reuse recovered waste paper as high-quality paper, and it is desired to improve the whiteness more than ever before. There is a need to remove fine ink particles. In order to remove fine particles with a flotation device, it is necessary to increase the chances of particles adhering to bubbles, and measures such as increasing the amount of air blown in, extending the residence time, and reducing the size of bubbles are necessary. It is taken. Among them, the miniaturization of bubbles is particularly important, and it is preferable to generate bubbles having a particle size of 5 × d (μm) or less in order to take ink particles having a particle size of d (μm).

From the above viewpoint, the present invention aims to provide a flotation separation device capable of generating ultrafine bubbles and effectively performing the flotation separation.

[0011]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems and includes an inner cylinder fixed vertically, an intermediate cylinder concentrically fixed to the outer side of the inner cylinder, and an outer side of the intermediate cylinder. Has an outer cylinder that is concentrically provided with an upper end plate and that rotates, and an air inlet that is provided in the lower portion of the outer cylinder that communicates with the gap between the inner cylinder and the intermediate cylinder. It is equipped with a bubble generating device that raises the space between the inner cylinder and the middle cylinder, reverses it at the upper part, lowers it between the middle cylinder and the outer cylinder, and discharges it from the lower edge of the outer cylinder. The present invention relates to a characteristic floating separation device.

[0012]

In the bubble generating device of the present device, the air descending between the fixed intermediate cylinder and the rotating outer cylinder receives a great shearing force. Since air is released into the liquid in this state, the air becomes ultrafine bubbles and is dispersed in the liquid. Therefore, in the flotation device provided with this, the chances that fine particles such as ink adhere to the bubbles increase. As a result, the performance of the flotation device is improved.

[0013]

1 is a perspective view of a first embodiment of the present invention.
This is an improved device of the first example of the prior art (FIG. 8). In the figure, 2X is an air injection part which is extended as compared with the prior art, and 31 is a bubble generator provided in the air injection part. Since the other parts are the same as those of the conventional technique, the description of the structure is omitted.

FIG. 2 is a sectional view of the bubble generating device.
In the figure, 32 is a pipe wall of the air injecting section 2 of the flotation device, 33 is an inner cylinder fixed to the same, 34 is outside the inner cylinder, and A fixed intermediate tube 35, a rotary shaft 35 rotatably held with respect to the inner cylinder 33, a motor 36, a belt 37 for transmitting the rotational driving force of the motor to the rotary shaft 35,
Reference numeral 38 denotes a support plate fixed to the inner cylinder 33, the rotary shaft 35 penetrating a through hole in the central portion, 39 and 40 bearing members fixed to the support plate, and 41 fixed to the bearing member. A mechanical seal member that forms a mechanical seal with the rotary shaft, 42 an outer cylinder located outside the intermediate cylinder, 43 an end plate of the outer cylinder, and 44 and 45 the end plates of the rotary shaft 35. A fixing member for fixing to the inner cylinder 3 has one end.
3 is an air inlet connected to the space between the intermediate cylinder 34 and the intermediate cylinder 34, and the other end is connected to an air source outside the apparatus. A is a raw material fluid, B is air, and G is bubbles.

In this apparatus, the air B injected from the air inlet 46 rises between the inner cylinder 33 and the intermediate cylinder 34, reverses, and descends between the intermediate cylinder 34 and the outer cylinder 42. .. At this time, since the outer cylinder 42 is rotating via the rotating shaft 35 that is rotated by the driving force of the motor 36, the air B receives a shearing force when descending between the intermediate cylinder and the outer cylinder. When this air is discharged into the raw material fluid A flowing inside the tube wall 32, it becomes dispersed as ultrafine bubbles G in this fluid.

Compared with the conventional type (FIG. 9), this bubble generating device exerts a shearing force on the air itself, so that the dispersing effect is large and it is easy to generate fine bubbles. In the conventional method, when the gas injection amount is increased, the bubbles are likely to coalesce into a bubble having a diameter of 1 to 2 mm, but in this method, due to the shearing effect, it is difficult to coalesce even if the gas injection amount is increased. Further, by changing the rotation speed of the outer cylinder 42, it is possible to control the bubble particle size and the number of bubbles to be generated. With the above operation, a large amount of bubbles having a diameter of 10 μm or less can be generated.

Therefore, in the flotation / separation device of this embodiment equipped with this bubble generating device, the conventional device (FIG. 8) is used.
It is possible to remove ink particles having a finer diameter (10 μm or less) as compared with. Also, by changing the rotation speed of the outer cylinder,
Since the bubble diameter can be changed, it is easy to deal with different raw materials.

FIG. 3 is a comparison diagram of performance test results between the conventional apparatus and the apparatus of the above-mentioned embodiment. In this test, the same raw material (newspaper) was used in solution (water 8
For 00 liters, 40 g of deinking agent, 84.2 g of sodium hydroxide, 600 g of sodium silicate, 229 hydrogen peroxide
What was treated with g) was diluted to a concentration of 1% and used. When the treatment liquid volume is 285 liter / min, the gas liquid ratio = 20%, and the inlet pressure = 2 kgf / cm ² , the dewatering rate measured at the final stage is shown in FIG. Is shown in. For the deinking rate, a value obtained by filtering the paper with a handmade paper according to the JIS method and measuring the paper with a particle analyzer was used (JIS-TAPPI paper pulp test method No. 39-82). As a result, it was found that the present example has a higher performance of removing the ink having a particle diameter of 10 μm or less than that of the conventional apparatus. Figure 4 shows the same conditions,
It is a comparative diagram of the performance test results when the amount of gas is increased and gas / liquid = 30%, and in this case as well, it was found that the device of this example was superior.

FIG. 5 is a perspective view of the second embodiment of the present invention. This is an improved device of the second example of the prior art (FIG. 11). In the figure, 31 is a bubble generator described in detail with reference to FIG. A plurality of this device is provided at the bottom of the main body 21. Along with this, the turbine and the motor for driving the turbine, which have been conventionally provided, have been abolished. The air intake 23 is connected to the air inlet 46 of the bubble generator 31 at the bottom of this device.

Compared with the conventional turbine system, the bubble generator of this embodiment has a large gas dispersion effect and is easy to generate fine bubbles. Therefore, the conventional device (Fig. 11)
It is possible to remove ink particles having a finer diameter (10 μm or less) as compared with

FIG. 6 is a comparison diagram of performance test results between the conventional apparatus and the apparatus of the above embodiment. In this test, in any of the devices, the raw material (newspaper of waste paper) was used in the same manner as that used in the first embodiment, the solution (40 g of deinking agent, 84.2 g of sodium hydroxide, silicic acid per 800 liter of water) What was treated with 600 g of soda and 229 g of hydrogen peroxide was diluted to a concentration of 1% was used. The processing liquid volume is 285 liter / min. Since the residence time was 40 minutes, the horizontal volume was 11.4 m ³ . Gas-liquid ratio is 1
It was 0.0 and the gas amount was 2850 liter / min.
Figure 6 shows the measured deinking ratio by separating the liquid at the inlet and outlet.
Is shown in. The performance of the conventional method is also shown for comparison. For the deinking rate, a value obtained by filtering the paper with a handsheet according to the JIS method and measuring the paper with a particle analyzer was used (JIS-TAPPI Paper Pulp Test Method No. 39-8).
2). The result is that this embodiment is more
It was found that the removal performance of ink having a particle diameter of 0 μm or less is high. FIG. 7 is a comparison diagram of the performance test results when the gas amount was increased to 12.0, that is, the gas amount was 3420 liter / min under the same conditions, and in this case also, the device of this example was used. It turns out that is better.

[0022]

The levitation separating apparatus of the present invention comprises an inner cylinder fixed vertically, an intermediate cylinder concentrically fixed to the outside of the inner cylinder,
It has an outer cylinder that is concentrically provided on the outside of the intermediate cylinder and has an end plate at the upper part, and a rotating outer cylinder, and an air inlet that is provided in the lower part of the intermediate cylinder and communicates with the gap between the inner cylinder and the intermediate cylinder A bubble generating device that raises the air sent from the air inlet between the inner cylinder and the intermediate cylinder, reverses it at the upper part, drops it between the intermediate cylinder and the outer cylinder, and discharges it from the lower edge of the outer cylinder. Is equipped with
It is possible to effectively remove particles of ink or the like in the finer raw material fluid than ever before.

[Brief description of drawings]

FIG. 1 is a perspective view of a first embodiment of the present invention.

FIG. 2 is a sectional view of a bubble generator used in the same embodiment.

FIG. 3 is a comparison diagram of performance test results between the embodiment and a conventional device.

FIG. 4 is a comparison diagram of performance test results under the other conditions between the embodiment and the conventional device.

FIG. 5 is a perspective view of a second embodiment of the present invention.

FIG. 6 is a comparison diagram of performance test results between the embodiment and a conventional device.

FIG. 7 is a comparison diagram of performance test results under the other conditions between the embodiment and the conventional device.

FIG. 8 is a perspective view of a first example of a conventional flotation device.

FIG. 9 is a divided perspective view of an air injection unit of the same device.

FIG. 10 is a sectional view of a mixing section of the apparatus.

FIG. 11 is a perspective view of a second example of a conventional flotation device.

[Explanation of symbols]

 1 Main Body 2, 2X Air Injection Part 3 Mixing Part 4 Separation Floating Head 5 Discharge Part 6 Raw Material Fluid Inlet 7 Compressed Air Inlet 8 Separation Material Outlet Port 9 Receptor Outlet 10 Air Nozzle 11 Air Chamber 12 Enlarged Rapid Compression Channel 21 Main Body 22 Raw material fluid inlet 23 Air intake port 24 Separated substance discharge port 25 Receptor outlet port 26 Turbine 27 Turbine drive motor 31 Air bubble generator 32 Floatation / separator device Air injection part pipe wall 33 Inner cylinder 34 Intermediate cylinder 35 Rotating shaft 36 Motor 37 Belt 38 Support plate 39, 40 Bearing member 41 Mechanical seal member 42 Outer cylinder 43 End plate 44, 45 End plate fixing member 46 Air inlet A Raw material fluid B Air C Separated discharge D Receptor E Mixed flow of raw material fluid and air F Micro turbulence G Bubble

Claims (1)

[Claims] 1. A vertically fixed inner cylinder, an intermediate cylinder concentrically fixed on the outer side of the inner cylinder, and an outer cylinder concentrically provided on the outer side of the intermediate cylinder and having an end plate on the upper part thereof to rotate. , And an air inlet provided at a lower portion thereof in communication with the gap between the inner cylinder and the intermediate cylinder, and air supplied from the air inlet is raised between the inner cylinder and the intermediate cylinder. A flotation device comprising a bubble generating device which is turned upside down and descends between an intermediate cylinder and an outer cylinder to discharge from a lower edge portion of the outer cylinder.