JPH0657670A - Flotator - Google Patents

Abstract

PURPOSE:To improve the removing efficiency of fine ink particles by connecting a specific gas-injection apparatus to an air-feeding port of an aeration zone. CONSTITUTION:A gas-injection apparatus 5 having a channel 13 for raw material liquid at the center and a tubular porous material 6 connected to an air feeding port 12 at the back is connected to the air-feeding port 12 of an aeration zone. Fine bubbles can be generated in the injection of air to improve the dispersing effect and the number of bubbles can be controlled simply by changing the injection rate of air.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a floater that can be used in a deinking device or the like.

[0002]

2. Description of the Related Art A conventional pressure type deinking module is shown in FIG.
The compressed air 1 is blown from several air nozzles provided in the circumferential direction to form a donut-shaped air chamber. At the same time as a part of the supply air is dissolved in the raw material liquid 2 under pressure, bubbles are generated by the mechanical shearing action of the raw material flow on the air chamber. Further, in FIG. 6, there are a mixing zone B and a separation zone C following the aeration zone A for dissolving air. In the mixing zone B, as shown in FIG. 8, several stages of expansion / contraction channels 9 are provided. First, the dissolved air in the raw material is deposited as fine bubbles with the ink particles as the nuclei by the cavitation action due to the sudden change in the pressure in the enlarged flow path. Next, acceleration / deceleration flow and micro turbulence in several stages of expansion / contraction flow
Due to this, collision and adhesion of ink particles with a wide size distribution of bubbles including fine bubbles are highly achieved. On the other hand, in the separation zone C, the bubbles having ink particles attached thereto are raised toward the interface to form bubbles containing the ink on the liquid surface in the D range. At this time, the flow pattern of the raw material in the separation zone C is controlled to maintain an appropriate turbulent flow, thereby suppressing the mixing of the fibers into the floss and preventing the precipitation of the fibers to improve the fiber yield. The floss on the interface is then ejected as reject 3 (range E) and the others are accept 4
Is introduced into the PDM device in the next stage.

[0003]

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. Especially, in the deinking device, it is 10 μm or less. It is necessary to remove the fine ink particles of In addition, in order to remove fine particles with a flotation machine, it is first necessary to increase the chances of particles adhering to the bubbles, such as increasing the amount of air blown, extending the residence time, and making the bubbles finer. Was taken. The effect of bubble size on flotation has been studied since the time it was used in mines, and it has been found that the effect is greatest when the bubble size is 5 times the particle size.
In order to remove ink particles having a size of 10 μm or less, it is desirable to generate bubbles having a size of 50 μm or less, but it has been insufficient with the conventional apparatus. The present invention has been proposed to solve the above conventional problems.

[0004]

For this reason, the present invention is mainly directed to an aeration zone for blowing air into a raw material liquid, a mixing zone for precipitating bubbles with ink particles in the raw material liquid as nuclei, and a separation zone for floating and separating the bubbles. In the floatator constituted by, the air supply port of the aeration zone is provided with a raw material liquid passage in the central portion, and a gas injection device provided with a tubular porous body communicating with the air supply port on the back side is connected to the air supply port. , Is a means for solving the problems.

[0005]

In the present invention, since the tubular porous body having the raw material liquid passage in the central portion is provided, fine bubbles can be generated at the time of injecting air as compared with the conventional type, and the dispersion effect is increased. Further, in the conventional method, if the gas injection amount is increased, the bubbles are likely to coalesce into a bubble of 1 to 2 mmφ,
In the present invention, since it is a fine bubble, it is difficult to unite. Furthermore, by changing the air injection amount, it becomes possible to control the number of bubbles while maintaining the fine particle size.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings. FIGS. 1 and 2 show an embodiment of the present invention. FIG. 1 shows an aeration zone A in which air 1 is mainly blown into a raw material liquid 2.
1 shows a floater composed of a mixing zone B for precipitating air bubbles with ink particles in the raw material liquid 2 as nuclei, and a separation zone C for floating and separating the air bubbles. See also FIG.
As described above, the air supply port 12 is provided in the aeration zone A.
Is provided with a gas injecting device 5 which communicates with the air supply port 5.
2 has a structure in which a tubular porous body 6 leading to 2 is provided. In addition, 7 is a support and 8 is a fine bubble. Next, the operation will be described with reference to FIG. 2. FIG. 2 shows the gas injecting means of the present invention. The air 1 supplied from the air injecting port 12 passes through the fine pores (30 to 50 μmmφ) of the tubular porous body 6. The fine bubbles 8 are dispersed in the raw material liquid 2 in the passage 13. FIG. 1 shows an overall view of a floatator using a gas injection device 5, and as shown in FIG. 2, a tubular porous body 6 is fixed inside a circular tube 11 of the floatator by a support 7. On the other hand, the porous body 6 used is Al ₂ O ₃
First, a sintered body of artificial abrasive grains of high quality can be considered, but any porous body having corrosion resistance and capable of being processed can be sufficiently used, and use of metal, plastic or the like is also conceivable.

The present invention will be described with reference to the following specific examples. The average pore size of the porous body is 40 μm, and the same raw material (newspaper waste) and solution (800 liters of water to 40 parts of the deinking agent) are used.
g, sodium hydroxide 84.2 g, sodium silicate 600
g, hydrogen peroxide 229 g) treated with a concentration of 1%
What was diluted so that it became The amount of processing liquid is
In the case of 285 liter / min, gas-liquid ratio = 20%, and inlet pressure = 2 kgf / cm ² , PDM is connected in six stages in series and the deinking rate measured at the final stage is shown in FIG. For the deinking rate, a value obtained by filtering with hand-made 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, in the case of the present invention, especially 10 μm
It was found that the following particle size ink removal performance is high.
Next, FIG. 4 shows the test results when the amount of gas was increased and gas / liquid = 30% under the same conditions as in the above specific example. Further, FIG. 5 shows the test results of the relationship between the average pore diameter and the average cell diameter of the porous body under the same conditions as the above two specific examples.
At this time, the porosity was set to 30%, and the average pore size for generating a large amount of bubbles having a diameter of 50 μm or less was 40 μm. Further, in order to maintain the bubble diameter of 50 μm, it is desirable that the average pore diameter of the porous body be 40 μm or less.

[0008]

As described in detail above, the present invention is constituted, and therefore, the removal of fine (10 μm or less) ink particles is improved by generating a large number of bubbles having a fine diameter as compared with the conventional method. You can Further, since the present invention is a pressure type, it is possible to dissolve air in the liquid,
Therefore, undissolved (precipitated) air generated when the dissolved air is depressurized can be used. Further, according to the present invention, bubbles having a small diameter are generated at the time of injecting air. Therefore, the number of bubbles can be controlled while maintaining the bubbles having a small diameter by adjusting the injection amount of air.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional side view of an entire floatator according to an embodiment of the present invention.

FIG. 2 is a detailed cross-sectional view of a gas injector for a floater showing an embodiment of the present invention.

FIG. 3 is a diagram showing the relationship between the ink particle size and the ink removal rate in the present invention and the related art.

FIG. 4 is a diagram showing a relationship between an ink particle size and an ink removal rate, which is different from that of FIG. 3 in the present invention and the related art.

FIG. 5 is a diagram showing the relationship between the average pore diameter and the average cell diameter of the porous body in the present invention.

FIG. 6 is a partial sectional side view showing the entire conventional floater.

FIG. 7 is a cross-sectional view showing a gas inlet of a conventional floatator.

FIG. 8 is a sectional view showing a mixing zone in a conventional floater.

[Explanation of symbols]

 1 Air 2 Raw Material Liquid 3 Reject 4 Accept 5 Gas Injector 6 Tubular Porous Body 7 Support 8 Micronized Air 11 Circular Tube 12 Air Supply Port 13 Raw Material Passage A Aeration Zone B Mixing Zone C Separation Zone D Bubble Separation E floss separation

Claims (1)

[Claims] 1. A floater comprising mainly an aeration zone for blowing air into a raw material liquid, a mixing zone for precipitating bubbles with ink particles in the raw material liquid as nuclei, and a separation zone for floating and separating the bubbles. A floater, characterized in that a gas injection device having a raw material liquid passage in the center and a tubular porous body communicating with the air supply port on the back is connected to the air supply port of the zone.