JP2003164711A - Separation method for solid matter of slurry by filter press apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for separating solid matter in a slurry using a simple filter press apparatus with a small amount of washing water without requiring structural alteration. <P>SOLUTION: After the slurry is supplied to a filter chamber 1 of the filter press apparatus through a slurry pipe 9 and solid matter are deposited as a filter cake 10 on a filter cloth 12, the slurry supply is stopped and washing water is supplied through a washing water pipe 8 in the same side as the slurry supply side and a filtered water discharge port 11 is alternately changed to the closed state and the opened state so as to keep the filter cake alternately in the state of immersion in washing water and non-immersion state, and then the resulting filter cake is pressed for dewatering and separated from the filter cloth to separate the solid matter in the slurry. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for separating a slurry solid content by a filter press device.

[0002]

2. Description of the Related Art Conventionally, a slurry solid content is, for example, aggregated in a solid-liquid separation thickener, then temporarily transferred to a washing tank, and after adding washing water and stirring, a filter press device or solid-liquid separation The water-soluble impurities are removed by dehydration with a centrifuge before separation. However, this method not only requires a large amount of washing water, but also requires a large-scale device with a washing tank.

When a filter press device is used, backwashing in which cleaning water is passed from the filtered water drainage port is generally used when removing the above-mentioned water-soluble impurities. The structure needs to be changed and strengthened.

When the slurry is pressed and dehydrated by the filter pressing device without removing the water-soluble impurities, a large amount of impurities remain in the dehydrated cake obtained.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned drawbacks of the prior art, and uses a filter press device that uses a small amount of washing water in the use of the filter press device and does not involve structural changes. The purpose is to separate the slurry solids.

[0006]

SUMMARY OF THE INVENTION The present invention is a method for separating a slurry solids content by a filter pressing device, characterized in that the following steps A to D are carried out in this order. To provide a method of separating the.

Step A: a step of supplying the slurry to a filter press device and depositing a solid content of the slurry as a filter cake on a filter cloth of the filter press device.

Step B: A step of stopping the supply of the slurry.

Step C: To the filter cloth, wash water is supplied to the filter press device from the same side as the supply of the slurry, and the filtered water drain port of the filter press device is closed and opened. A step of repeating the state in which the filter cake is immersed in the wash water and the state in which it is not immersed, by alternately switching.

Step D: a step of pressing the filter cake for dehydration and then separating it from the filter cloth.

Since the dehydrated cake obtained by the method for separating the slurry solids by the filter press of the present invention has a low concentration of water-soluble impurities, it is not only easy to process, but also the main component of the dehydrated cake is recycled as a raw material. When using it, there is an advantage that it is not necessary to deal with the corrosion resistance of the equipment and the quality of the product is not impaired.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the concentration of impurities in the slurry introduced into the filter press is preferably 0.1 to 5.0% in terms of dry mass. 5.
If it exceeds 0%, it takes a long time for cleaning, which makes it difficult to carry out the cleaning. Further, if it is less than 0.1%, the effect of the present invention is not sufficiently exhibited. The water-soluble impurities to be removed are not particularly limited as long as they are easily eluted in the wash water.

Although the washing water to be used is not particularly limited, drainage having a low impurity concentration such as industrial water and blowdown water of open cooling water is preferably used. Also, there is no particular limitation on how to use these, and in addition to the method of using only industrial water alone, the industrial water is used after using low-priced drainage with low impurity concentration in the initial stage of filter cake washing. It can be selected arbitrarily.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a structural view showing one embodiment of a filter press device for carrying out the method for separating a slurry solid content of the present invention, and FIG. 2 is a sectional view of the filter press device used in the present invention.

First, in step A, the slurry whose supply amount is controlled by the slurry supply solenoid valve 4 is introduced from the slurry tank 2 by the slurry pump 3 into the filtration chamber 1 in the filter press apparatus through the slurry pipe 9. , The solid content is deposited on the filter cloth 12 as the filter cake 10.

Next, in step B, the slurry supply solenoid valve 4 is closed to stop the slurry supply. After that, the slurry supply solenoid valve 4 is consistently kept closed until the step D is completed.

Then, the process C is performed. The wash water controlled by the wash water supply solenoid valve 7 is introduced from the wash water tank 5 by the wash water pump 6 into the filtration chamber 1 through the wash water pipe 8 to wash the filter cake 10. After washing the filter cake 10, the filtered water that has passed through the filter cloth 12 is filtered water drain port 1
Filtered water drain pipe 13 passing through 1 and connected by a flexible pipe
After moving to, it is discharged as filtered water from the filtered water drain port solenoid valve 14. Note that the cleaning water supply solenoid valve 7 is kept open throughout the process C.

What is important in this step C is the adjustment of the time for carrying out the step of keeping the filtered water drain port solenoid valve 14 closed and filling the filter chamber 1 with washing water. If this time is too short, there will be a portion where the washing water does not reach the inside of the filtration chamber 1, and the impurity removal rate will decrease. On the contrary, if this time is too long, the wash water pump 6 will be shut off for a long period of time, which may lead to a failure of the wash water pump 6, which is not preferable. Therefore, the filtered water drain port solenoid valve 14 is preferably closed for 10 to 60 seconds. Further, it is more preferable to discharge the filtered water in which impurities are eluted by opening the filtered water drain port solenoid valve 14 for a time equal to the time of introducing the cleaning water into the filtering chamber, and the time is 10 to 30. It is preferably set to 2 seconds. Further, a step of filling the filter chamber with washing water,
By alternately repeating the step of discharging filtered water 3 to 10 times, the effect of removing impurities is significantly improved.

In step D, the filter cake 10 is pressed and dehydrated, and then separated from the filter cloth 12 to obtain a dehydrated cake.

[0020]

EXAMPLES The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited thereto. In carrying out the present invention, a filter press device ISDC-L1500 * 16/18 manufactured by Ishigaki Co., Ltd. was used.

[Example 1 (Example)] In a mass of 2000 kg,
A slurry containing 180 kg of a solid content containing calcium fluoride as a main component was introduced from the slurry tank 2 into the filtration chamber 1 in the filter press device by the slurry pump 3. It should be noted that the slurry contains sodium chloride as an impurity, and as a result of analysis by an ion chromatography method, the chloride ion concentration is 2.1 in terms of dry mass.
%Met.

Next, with the filtered water drain port solenoid valve 14 closed, the wash water supply solenoid valve 7 is opened to filter the industrial water into the filtration chamber 1.
And the washing of the filter cake 10 on the filter cloth 12 was started. After that, the washing water supply solenoid valve 7 is kept in an open state consistently until pressing. Subsequently, 34 seconds after the cleaning water supply solenoid valve 7 was opened, the filtered water drainage solenoid valve 14 was opened to discharge the filtered water. 20 seconds later, the filtered water drain port solenoid valve 14 is closed to fill the filter chamber 1 with washing water, and 20 seconds later, the filtered water drain port solenoid valve 14 is closed.
Was opened, and filtered water in which impurities were eluted was discharged. The step of filling the washing water in the filtration chamber 1 and the step of discharging the filtered water were repeated 9 times at intervals of 20 seconds. The total amount of industrial water used for washing the filter cake 10 was 7500 liters when the opening / closing operation of the filtered water drain port solenoid valve 14 was alternately repeated 9 times.

Next, the washed filter cake 10 is pressed and dehydrated, and then the chloride ion concentration of the dehydrated cake obtained by separating from the filter cloth is measured by ion chromatography. For the purpose of investigating the presence / absence of variations in the degree of impurity removal in each chamber of the filtration chamber 1, the slurry / cleaning water inlet side of the filtration chamber 1 is further provided with two points at the center and the lower end. On the side of the hydraulic pump farthest from the water inlet, a total of 4 points at the center and the bottom
At this point, the chloride ion concentration in terms of dry mass in the dehydrated cake was measured, and the results are shown in Table 1.

[0024]

[Table 1]

Here, the dehydrated cake after opening and closing three times is R
un-1, the dried cake after opening and closing 6 times Run-2,
The dehydrated cake after opening and closing operation 9 times is designated as Run-3. Ru
The chloride ion concentration of n-1 was 0.36% and the removal rate was 83.
%, The chloride ion concentration of Run-2 reached 0.07%, and the removal rate reached 97%. Furthermore, in Run-3, the chloride ion concentration was lowered to 0.01%, indicating that impurities could be sufficiently removed.

[Example 2 (Comparative Example)] The slurry used in Example 1 was aggregated in a solid-liquid separation thickener, then temporarily transferred to a washing tank, and after adding 7500 liters of washing water and stirring, a filter was added. The chloride ion concentration of the dehydrated cake obtained by dehydrating with a press was 0.04%. That is, when the conventional washing method is used to wash with the same amount of washing water as in Example 1, the chloride ion concentration of the dehydrated cake is reduced to only 0.04%.

[Example 3 (Comparative Example)] The slurry used in Example 1 was aggregated in a solid-liquid separating thickener, then temporarily transferred to a washing tank, 31500 liters of washing water was added, and after stirring, a filter press was performed. When the chloride ion concentration of the dehydrated cake obtained by dehydrating with a device was measured, it was 0.01
%showed that. That is, when using the conventional cleaning method,
The chloride ion concentration of the dehydrated cake is the same as in Example 1, 0.01%
Approximately four times as much wash water as in Example 1 is required to reduce

[0028]

According to the method for separating a slurry solid content by the filter press device of the present invention, a simple filter press device which uses a small amount of washing water in the use of the filter press device and does not involve a structural change is used. The slurry solids can be separated.

Further, since the dehydrated cake obtained by the method for separating the slurry solids by the filter pressing apparatus of the present invention has a low concentration of water-soluble impurities, the treatment becomes easy. In addition, when the main component of the dehydrated cake is recycled as a raw material, there is no need to deal with the corrosion resistance of the equipment, and the quality of the recycled product is not impaired.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing an example of an embodiment of a filter press device for carrying out a method for separating a slurry solid content by the filter press device of the present invention.

FIG. 2 is a diagram schematically showing a cross-sectional view of a filter press device used in the present invention.

[Explanation of symbols]

1: Filtration room 2: Slurry tank 3: Slurry pump 4: Slurry supply solenoid valve 5: Wash water tank 6: Wash water pump 7: Wash water supply solenoid valve 8: Wash water pipe 9: Slurry tube 10: Filter cake 11: Filtered water drainage port 12: Filter cloth 13: Filtered water drain pipe 14: Filtered water drain port solenoid valve

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4D018 AA03 AA07 AA11 AA22 BB35                       CC02 CC03 CC06 DD00

Claims (2)

[Claims] 1. A method for separating a slurry solid content by a filter pressing apparatus, wherein the following steps A to D are carried out in this order: Step A: Supply the slurry to the filter press machine,
Depositing the solid content of the slurry as a filter cake on the filter cloth of the filter press device. Step B: A step of stopping the supply of the slurry. Step C: To the filter cloth, wash water is supplied to the filter press device from the same side as the supply of the slurry, and the filtered water drain port of the filter press device is alternately switched between a closed state and an open state. Thereby, the step of repeating the state where the filter cake is immersed in the washing water and the state where it is not immersed. Step D: A step of pressing the filter cake to dehydrate it and then separating it from the filter cloth. 2. In the step C, 3 to 1 depending on whether the filter cake is immersed in the washing water or not.
The method for separating a slurry solid content by the filter press device according to claim 1, which is repeated 0 times.