KR810000785B1 - Process and an installation for the klimination by the floatation of impurities in the form of solid particles contained in a liquid - Google Patents

Abstract

The impurities in the form of solid particles contained in a liquid is eliminated in the floating container(1) by the floating. The floating container(1) comprises flow-inlet port and air babbles mixing chamber(8). The fluid flows through the mixing chamber walls which has many through-holes, through which air stream is supplied. Flow velocity is adjusted and air bubbles volume is changed by the distance between two walls.

Description

Apparatus for removing impurities contained in the form of solid particles in a liquid by bar wire

1 is a schematic elevation view of a multi-layered installation for removing ink from gripping pulp according to the present invention.

2 is a horizontal cross-sectional view taken along the line A-A of FIG.

3 is a vertical longitudinal section in which the mixing chamber is enlarged.

4 is a cross-sectional view taken along the line B-B in FIG.

5 is an enlarged vertical sectional view showing another structural example of the mixing chamber.

6 is a cross-sectional view taken along the line C-C of FIG.

7 shows the whiteness curve of the pulp.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for removing impurities contained in a liquid in the form of solid particles by flotation, and in particular, air bubbles in a liquid stream in a float vessel. A device for removing impurities which floats on a liquid surface to generate bubbles to lift impurities by injecting them into a state in which air bubbles are dispersed in the liquid and adhered to the impurities. It is about.

The flotation method as described above is known as a method for removing ink from the papermaking pulp produced from the gripping. According to this known method, air is introduced directly into the bottom of the bath by suction, using a propeller which is also useful for the careful stirring and dispersion of the fiber suspension in the bath.

By introducing air directly into the pulp, it is possible to reliably control the air pressure, and thus to control the diameter of the bubbles depending on the volume of the air. The volume of air can in this case be adjusted within limits. It is possible to increase the air pressure by increasing the volume of air, and consequently to increase the diameter of the bubbles, while with this known method it is not possible to reduce the diameter of the bubbles while increasing the flow rate of the air.

Such a decrease in the diameter of the bubbles is necessary to separate the impurities in the case of any kind of impurities. Surprisingly, it was found here that the present invention makes it possible to selectively separate impurities by the flotation method by independently controlling the dimensions of the bubbles and the volume of air. Thus, for example, it is possible to obtain bubbles having different dimensions, respectively, in order to loosen the ink, in the case of ink removal of the pretreated paper pulp, or in order to float the ink or filler such as kaolin. Can be selectively separated.

The present invention aims, in particular, to provide a device capable of adjusting the dimensions of the bubbles independently of the volume of air mixed in the water to which impurities are to be removed. To this end, the present invention provides that the liquid circulates in at least one mixing chamber in a thin layer prior to introducing air and liquid into the sub-tank, at the same time crossing the passage of the liquid layer and Air is introduced into the liquid layer along a portion of the passageway.

If the liquid is a fibrous suspension, such as paper pulp, the pulp is forced through a narrow room in a thin layer and contacted with the injected and dispensed air in a direction transverse to this liquid thin layer containing the suspended fibers, thereby effectively exchanging the fibers. Friction and cleaning were found.

According to one embodiment of the apparatus of the present invention, the thickness of the liquid layer in the mixing chamber and the passage speed of the liquid in the room are controlled. In the case of ink removal of pulp prepared from phage, the volume of air mixed with the pulp and the pulp passage speed in the mixing chamber affect the whiteness of the pulp, and by controlling these factors, the temperature of 57 ° to 66.5 ° It has been found that various whiteness levels can be obtained.

This control makes it possible to minimize the waste volume and achieve purification. In addition, according to one embodiment of the device of the present invention, the length of the passage through which air enters into the liquid is controlled.

Thereby, the amount of air can be proportionally increased and decreased in the liquid layer passing through the mixing chamber. According to another embodiment, air bubbles are guided to the hopper with the air flow and the air is recovered for recirculation.

In the case of performing a barge using a plurality of barge tanks, a mixture of air and liquid from one mixing chamber can be introduced into the various baths each time. Therefore, the size of the bubbles can be controlled individually for each set, and impurities can be selectively recovered.

In the case of liquids containing fibers, cleaning and depletion entering the first flotation tank can be recirculated to the liquid in order to minimize the loss of fibers.

According to the invention the apparatus comprises a narrow mixing chamber through which at least one thin layer of cleaned and depleted liquid can pass, provided in an upstream side of the subline, in a direction across the liquid layer on the passage of the chamber. Has means to allow air to flow. According to one embodiment, the mixing chamber is bounded by two parallel walls that are separated from each other so that the liquid to be purified and degraded can pass therethrough. According to another embodiment, the mixing chamber has means for adjusting the isolation distance of said one wall.

Hereinafter, the apparatus showing the features of the present invention will be described in detail again. The device shown represents one bonded example of the present invention for removing the ink of the pulp produced from the waste paper, which is merely an example of the present invention.

The device shown comprises four sub-ships (1) (2) (3) (4). These squares are annular and are arranged in the axial direction in order to form a four-stage tower having a plurality of bottom surfaces 5. Of course, this tower can also be configured as a multi-stage tower other than four.

Paper pulp in the form of a suspension of decomposed, chemically pretreated fibers contains a blowing agent, and first passes through the mixing chamber 8 through the pipe 7 to the inlet of the flotation tank 1 via a pump 6. Is introduced. This mixing chamber 8 has a thin layer shape, and there is a narrow passage through which the suspension of the fiber passes. When passing through this passageway, air is simultaneously introduced in or along a portion of the passageway of the pulp liquid layer. This air is introduced through a pipe 9 via a valve 10, which is connected to a pressurized air source, not shown. The mixing chamber 8 communicates with the subline tank 1 through the pipe 11, and the pipe is introduced in the collecting direction to the cylindrical wall of the tank near the bottom surface 5 of the subline tank 1. The fiber suspension therefore turns the attention of the annular center pipe 12. Bubbles generated in the fiber suspension adhere to impurities, and the impurities float with the bubbles to the surface. Bubbles are discharged from the outlet 18 formed in the central pipe 12 and enter the central pipe 12. The movement of the bubbles is caused in part by the rotational movement of the fiber suspension and in part by the flow of air supplied over the suspension. And the vertical plate 50 disposed on the pump liquid level guides the bubbles to the outlet. Bubbles are collected in a hopper 13 arranged to surround the center pipe 12 and are accommodated in a waste tank 37 filled with water. The air flow for discharging the bubbles to the floater is introduced into the upper portion of the floater through the pipe 14. The pipe 14 is connected to a suction device 15 arranged on the upper side of the axially long columnar pipe 16, and the air for bubble discharge is recycled and used. The conical pipe 16 is arranged concentrically with the central pipe 12 and communicates with all the sub-ships in each stage in common. The foaming air enters the vagina through the opening 17 and exits the bath through the outlet 18. As it exits the bath, the bubbles that come with this air fall into the hopper 13 by gravity and the air exits upwards through the pipe 16. The pipe 16 extends up to the next subline 2 to be a conical portion having a tapered tip, and the portion faces the larger pipe portion.

The pipe part having a large diameter is a pipe part for recirculating the bubble discharge air of the adjacent buoys 2 and other stages of the buoys 3 and 4. One cyclone is formed by the constituent parts of the pipe 16. The cyclone gives the foam a centrifugal velocity, and air is introduced into the pipe 16 by the action of the suction device 15. It is aspirated off from the foam and returned to the pipe 14 to be reused for the discharge of the foam.

The pulp partially purified in the sub-tank 1 exits the sub-tank 1 via a pipe 19 with a pump 20. The pressure in the pipe 19 can be increased or decreased by the pump 20. The pipe 19 extends to the mixing chamber of the floater 4 located at the final stage of the tower.

The purification processing performed here is the same as in the case of the sub-tank of the first stage, and the same purification is performed sequentially in another sub-tank. As a result, pulp, or water containing fibers, gradually increases its purity. During this time, the bubbles collected in the different levels of the buoys are sent to the lower buoys. Bubbles discharged from the buoys of the first and other stages containing the exclusion material may of course be recycled or discharged to the outside for treatment by a separate device at each stage. This depends on the type of pulp product intended.

In addition, the apparatus again closes the subsidiary tank 40 of the final stage, the monitoring window 41 for rapid discharge for purification, the discharge valve 42 for emptying the empty space into the tub installed for each subsidiary ship, A flap 46 installed in the air discharge pipe for foaming, a floor 43 installed in the pipe 12 to receive the circulated exclusion material, and a pipe for discharging the exclusion material installed in the first sub-ship 1 44 and a pipe 45 for discharging the pulp in the flotation tank 2 which treats the most purified pulp.

3, 4, 5, and 6 show two structural examples of the mixing chamber, respectively. In the case of the structural example shown in FIG. 3 and FIG. 4, the mixing chamber is formed of a rectangular portion composed of two parallel surface walls 21 and 22 attached in a body 23 of one parallel hexagonal body. The part forms the groove | channel which communicates with the inlet pipe 7 and the outlet pipe 11 of pulp. One wall 21 is movable in parallel with respect to the other wall 22, it is moved by the screw rod (24). The screw rod 24 is guided using the handle 25 in the threaded hole 26 formed in the sleeve 27 attached in the adjacent upper wall of the parallelepiped 23, and the two parallel parts The distance between the walls 21 and 22 is adjusted, thereby determining the thickness of the liquid layer of the pulp under the action of air jets. The wall 21 is provided with a diaphragm to seal the room. On the other hand, the wall 22 is made of a porous material. In the specific example as shown, a frit glass capable of passing an air jet through a liquid layer of pulp indoors as its porous material is considered. In this case, it is advantageous to install the plate 28 which can close a part of the surface of the air passage of the mixing chamber frit glass to adjust the size of the air flow passage surface.

In the structural example shown in FIG. 5 and FIG. 6, the shape of the mixing chamber 8 is conical, and has two parallel parallel cone-shaped walls 29 and 30, between both walls. A passage of pulp liquid is formed in the. The pulp is fed through a nozzle 31 which penetrates the wall 29 of the mixing chamber and enters the room in a tangential direction, and the pulp rotates indoors. Air is supplied and injected from an air inlet pipe 32 connected to a compressed air source (not shown) through a plurality of holes 47 formed in the inner wall 30.

The conical inner wall 30 is slidable laterally with respect to the outer wall 29, so that the distance between the inner wall 30 and the outer wall 29 is adjusted. Therefore, as a result of this, the thickness of the pulp liquid layer is adjusted. For this purpose, the rotatable inner wall 30 is adapted to be controlled in position by a tube 32, the tube 2 being an air supply tube at the same time. In the inner wall 30 a conical closure 33 is arranged. This block 33 is attached to two rods 3 and 35 which can slide in the cross section of the inner wall 30, and if necessary, a portion of the air distribution hole is blocked to allow the air to flow into the mixing chamber. The passage area can be adjusted. In this way, the control of the air inflow can be carried out independently of the flow rate and flow rate of the pulp, so that bubbles can be generated appropriately for the flow of ink, kaolin or fiber in each sub-tank, and thus the selection of these components. Separation can be achieved.

Although the present invention has been described in particular with regard to an apparatus for ink removal of paper pulp, the present invention may be used for other uses, for example, to clean ore or to purify white water by flow of fibers. . White plots 48 and 49 are plotted in FIG. 7 for the air volume to air volume ratio obtained from the laboratory test results and the pulp velocity in the mixing chamber. In the side view, the ratio of the pulp whiteness Scann on the vertical axis and the pulp volume l on the horizontal axis is indicated. Curve 48 displays pulp whiteness when the flow rate of pulp is 4.23 m / sec, and another curve 49 displays pulp whiteness when the flow rate of pulp is 6.35 m / sec.

It can be seen that the difference in whiteness from 57 ° to 66.5 ° Scan can be obtained by adjusting the air-pulp mixing ratio and the pulp speed in the mixing chamber. The above test was carried out using magazine-type grippers, and used was a gripper containing about 50% of mechanical pulp whose whiteness of the unprinted margins was 6.65 ° scan.

By applying the apparatus of the present invention, the whiteness of the printing portion containing about 2% of the ink can be increased from 46 ° to 66.5 scan with a holding time of 20 minutes. After a 2.5 minute hold, the whiteness has already reached 46 ° to 64.5 ° scan. In the case of treating with the conventional method using the same sebum, even in the best result, only 62.3 degrees scan was achieved after the holding time of 20 minutes, and only about 54 degrees scan whiteness was achieved after 2.5 minutes.

The specific examples and the illustrated device examples as described above do not limit the present invention, and various implementation methods are possible within the scope of the present invention described in the claims.

Claims (1)

Liquid in the shape of a solid solid consisting of at least one float chamber, an inlet for introducing liquid into the tank, and a liquid passing through the inlet to suck air and generate air bubbles therein. In the apparatus which removes the impurity contained in it by a flotation, the said mixing chamber has many through which at least one of the opposed walls which penetrate it forms the flow path of the liquid which passes through this mixing chamber. A wall having a hole of air, ventilation means for supplying an air stream through the hole to generate air bubbles in the liquid flowing through the flow path, and the walls being relatively mutually spaced apart from each other. And by decreasing and increasing the width of the passages between the walls, respectively, thereby controlling the flow rate of the liquid passing through the passages, thereby half Control device and wherein the inlet consisting of a means for introducing a liquid to the upstream end of said passage for varying the size of air bubbles formed in.

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