JPH11262604A - Filtration method with filter press - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance dehydration efficiency by increasing the feed pressure of a slurry contg. particulate solid material fed into a filter chamber to close- filled cake into the chamber when the slurry is filtered with a filter press and then blowing air under high pressure on the close-filled cake to remove the water in the cake. SOLUTION: A stock. soln feed valve SV on a stock soln. feed pipe 20 is opened to feed a stock soln. comprising a slurry contg. a particulate solid material to the stock soln. introduction hole 10 of a filter press and the slurry is introduced into the filter chamber between adjacent filter plates 5 and filtered. At this time, the feed pressure of the slurry is measured with a pressure gauge 31 and a cake is close-filled into the filter chamber by keeping the feed pressure at such a high value as about 10-20 kg/cm<2> G. The filtrate is discharged from filtrate outlets 11-14. Blow air is then blown under high pressure on the close filled cake from the 2nd filtrate inlet 12 of each of the filter plates 5 to remove the water in the cake. The blow filtrate is discharged from the 1st filtrate outlet 11 through the 1st filtrate discharge pipe 21 and a bypass pipe 25.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a filtration method using a filter press.

The present invention is applicable to both a double filter press in which a large number of filter plates and filter frames are alternately arranged and a simple filter press in which a large number of filter plates are arranged.
In this specification, for convenience of explanation, the term "filter plate" is used to include not only a filter plate but also a filter frame.

[0003]

2. Description of the Related Art In general, when a suspended substance in a slurry is subjected to solid-liquid separation by a filter press, the resulting cake forms a solid material having a constant water content and having relatively good transportability. Here, it is preferable that the water content of the cake is as low as possible. However, as a conventional means for dewatering the cake, first, the slurry is passed through a slurry pump at a low and medium pressure of 4 to 7 kg / cm ² by a filter press. After feeding into the filter chamber to form a cake, then 7 to 20 kg /
By pressing the pressed membrane against the cake side at a high pressure of ² cm, a method of compressing the cake filled in the filtration chamber to cause a volume change and reducing moisture is performed, and most cakes are It can be processed by this conventional method.

[0004]

However, cakes containing very colloidal particulate solids, such as, for example, clay, calcium compounds, pigments or ceramics,
Softened and fluidized by the application of physical external force,
Since a so-called thixotropic (thixotropic) phenomenon is caused to break down the form of the solid, transport and supply become impossible.

[0005] That is, the cake obtained by filtering the slurry containing the fine solid particles has a form of a solid having good transportability, but is supplied in a transport process by a conveyor or a kneader or by a feeder. In the process, by repeatedly receiving a physical pressure due to external vibration, stirring, kneading, or the like, the material softens and fluidizes, and a so-called thixotropic (thixotropic) phenomenon occurs. Due to this softening phenomenon, the cake loses its solid form, making it impossible to transport or supply the cake, often causing troubles in the process of transporting the cake or in the storage stage by the hopper, and the cake processing. However, there is a problem that the workability of the method is significantly reduced.

[0006] The inventors of the present invention have conducted intensive studies in view of the above points, and as a result, when filtering a slurry containing fine solid particles, the filling pressure of the cake generated from the slurry supplied into the filter chamber of the filter press was increased. In order to make the cake denser and to reduce the excess voids in the cake as much as possible, and to blow air (blow) at a high pressure into the cake in this state, it is possible to remarkably eliminate the thixotropic property of the cake. They have found and completed the present invention.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, and to eliminate the thixotropic property of cake in the filtration of a slurry containing fine solid particles, and to reduce the thixotropic property of the cake in the process of transporting the cake or storing it in a hopper. The use of a filter press that can prevent the softening and fluidization of the cake beforehand, does not cause any operational troubles, is easy to operate, does not require special equipment, and is inexpensive. The aim is to provide a filtration method.

[0008]

In order to achieve the above object, a filtration method using a filter press according to the present invention is directed to a method for filtering a slurry containing fine solid particles using a filter press. ,
It is characterized in that the supply pressure of the slurry into the filter chamber is increased, the cake is densely filled in the filter chamber, and air is blown at a high pressure to the densely packed cake to remove water in the cake.

According to the second aspect of the present invention, when the slurry containing the fine solid particles is filtered by a filter press, the slurry is supplied into the filtration chamber to form a cake, and then the cake is pressed and densely filled. Along with
Air is blown to the densely packed cake at high pressure to remove moisture in the cake.

[0010]

Embodiments of the present invention will now be described with reference to the drawings.

In this specification, the terms front and rear refer to the first head side as the front and the rear head side as the rear. Therefore, the left and right correspond to the front-back direction.

[0012] The filtration method using a filter press according to the present invention includes a first invention according to claim 1 and a second invention according to claim 2. Embodiments of both inventions are different from each other due to the difference in the air blow system. There are three embodiments.

FIG. 1 shows a flow sheet according to a first embodiment of the first and second inventions, FIG. 2 shows a flow sheet according to a second embodiment of the first and second inventions, respectively, and FIG. FIG. 3 shows a flow sheet according to a third embodiment of each of the first and second inventions. FIG. 4 shows a schematic view of the entire filter press.

Referring first to FIG. 4, the filter press is slidably supported by a first head (1) having a machine frame, a rear head (2), a loose head (3), and left and right side plates (not shown). It has a number of filter plates (5) arranged between the first head (2) and the loose head (3). The front and rear filtration surfaces of the filter plate (5) are covered with a filter cloth (not shown). Then, all the filter plates are operated by the operation of the hydraulic cylinder (4) provided in the rear head (2).
(5) is tightened to make a closed state.

In the first invention of the filtration method according to the present invention,
In filtering the stock solution consisting of the slurry containing the fine solid particles by the filter press, first the adjacent filter plate (5)
The supply pressure of the slurry into the filter chamber during (5) is increased to densely fill the cake into the filter chamber. Then, blow air is blown at a high pressure to the densely packed cake to remove moisture in the cake.

In the second invention, when a stock solution comprising a slurry containing fine solid particles is filtered by a filter press, first, the slurry is supplied into a filter chamber between adjacent filter plates (5) and (5) to form a cake. . Then, the cake is squeezed and densely filled, and air is blown onto the densely packed cake at a high pressure to remove moisture in the cake.

The outline of the first and second aspects of the present invention is as follows.
It is as follows.

First invention: high-pressure filling of slurry + air blow Second invention: normal filling of slurry + cake pressing + air blow Here, the stock solution to be filtered is, for example, a slurry such as a calcium carbonate slurry. The concentration is usually preferably about 5 to 15% by weight.

Next, referring to FIG. 1 showing a flow sheet according to the first embodiment of the first and second inventions, each filter plate (5)
An opening (10) for a stock solution (slurry) is opened in the center of the
Also, at the four corners of each filter plate (5), there are first to fourth filtrate outlets (11) and (12).
(13) and (14), and these filtrate outlets (11) (12) (13) (1
4) are the first to fourth filtrate discharge pipes (21) (22) (23) (24), respectively.
Leads to.

Here, the undiluted solution inlet at the center of each filter plate (5)
In (10), a stock solution is supplied from a stock solution supply pipe (20), and in the middle of the stock solution supply pipe (20), a stock solution supply valve (SV) is interposed and a pressure gauge (31) is provided. ing.

The tip of the first filtrate discharge pipe (21) joins with the tip of the fourth filtrate discharge pipe (24) at a connection point (A1), and from this junction, the filtrate discharge pipe (26) And / or a blow filtrate discharge pipe (27).
The automatic control valves (CV1) and (CV2) are interposed on the way of (27).

A bypass pipe (25) is connected to a portion near the end of the first filtrate discharge pipe (21) at connection points (B1) and (B2), and one of the filtrates between both connection points (B1) and (B2). An automatic control valve (CV5) is interposed in the discharge pipe portion (21a), and an opening adjustment manual valve (MV) is interposed in the middle of the other bypass pipe (25). In addition,
A pressure gauge (32) is provided at the bypass pipe connection point (B1) of the first filtrate discharge pipe (21).

An automatic control valve (CV6) is interposed at a portion near the start end of the third filtrate discharge pipe (23). The distal end of the second filtrate discharge pipe (22) is connected to the tip of the third filtrate discharge pipe (23) at the connection point (A2), and the third filtrate discharge pipe (2) is connected to the third filtrate discharge pipe (2).
The tip of (3) is connected to a portion near the tip of the fourth filtrate discharge pipe (24) at a connection point (A3).

An automatic control valve (CV3) is interposed at the distal end of the third filtrate discharge pipe (23) downstream of the distal end of the second filtrate discharge pipe (22), and the fourth filtrate discharge pipe (24). An automatic control valve (CV4) is interposed in the portion near the start end of ().

A blow air supply pipe (28) is connected to an intermediate portion of the third filtrate discharge pipe (23) at a connection point (A4), and a blow valve (BV) is provided in the middle of the blow air supply pipe (28). Is interposed. A pressure gauge (33) is provided at the connection point (A4) of the third filtrate discharge pipe (23) to the blow air supply pipe.

The first embodiment of the first invention (high-pressure filling of slurry + air blow) will be described in detail with reference to the flow sheet of FIG.

First, in the filtration step, the stock solution supply pipe (2
0) Opening the undiluted solution supply valve (SV), the undiluted solution consisting of the slurry containing the particulate solid material is fed from the undiluted solution supply pipe (20) to each filter plate of the filter press (5), and the undiluted solution introduction port (10) in the center part And the slurry is introduced into the filter chamber between the adjacent filter plates (5) and (5) to perform filtration.

At this time, the filling pressure (supply pressure) of the slurry is measured by a pressure gauge (31) in the middle of the stock solution supply pipe (20), and the slurry filling pressure is maintained as high as about 10 to ²⁰ kg / cm ² G. And tightly fill the cake in the filter room.

The filtrate is supplied from the first to fourth filtrate outlets (11), (12), (13) and (14) at the four corners of each filter plate (5) through the first to fourth filtrate discharge pipes (21).
(22) Discharge through (23) (24). For this reason, the filtrate discharge pipe
(26) Open the automatic control valve (CV1) on the way and open the blow filtrate discharge pipe.
(27) The automatic control valve (CV2) on the way closes. Third filtrate discharge pipe
Open the automatic control valve (CV3) of (23), open the automatic control valve (CV4) near the beginning of the fourth filtrate discharge pipe (24), and open the filtrate discharge pipe near the tip of the first filtrate discharge pipe (21). Part (21a) automatic control valve
Open (CV5) and open the manual valve to adjust the opening of the bypass pipe (25).
(MV) is also open. Also, open the automatic control valve (CV6) near the start end of the third filtrate discharge pipe (23) and open the blow air supply pipe (2).
The blow valve (BV) in the middle of 8) is closed.

After the cake is densely filled in the filter chamber, blow air is blown at a high pressure to the densely packed cake to remove the water in the cake. At this time, the blowing of the blow air is performed from the second filtrate outlet (12) of each filter plate (5).

That is, the blow air is supplied from the blow air supply pipe (28) to the third filtrate discharge pipe (23) connected at the connection point (A4).
Through the second filtrate outlet (12) through the middle portion of the second filtrate and the second filtrate discharge pipe (22) connected at the connection point (A2) from the pipe (23). The blow pressure of the blow air is measured by a pressure gauge (33) in the middle of the blow air supply pipe (28), and the blow pressure of the blow air is set to ² to 10 kg / cm ² G.

The blow filtrate is discharged from the first filtrate outlet (11) of each filter plate (5) through the first filtrate discharge pipe (21) and the bypass pipe (25), and discharged from the blow filtrate discharge pipe (27). I do.

For this purpose, the automatic control valve (CV2) on the way of the blow filtrate discharge pipe (27) is opened, and the automatic control valve (CV1) on the way of the filtrate discharge pipe (26) is closed. Also, open the opening adjustment manual valve (MV) in the middle of the bypass pipe (25), and open all remaining automatic control valves (CV3) to
(CV6) is closed.

By adjusting the opening of the manual valve (MV) in the middle of the bypass pipe (25), the pressure of the blow air in the filter chamber is adjusted so that the discharge amount of the blow filtrate is increased as much as possible. Is what you do.

Next, based on the flow sheet of FIG.
The first embodiment of the second invention (normal filling of slurry + cake pressing + air blow) will be described in detail.

First, the filtration step is almost the same as that of the first embodiment of the first invention, except that the slurry filling pressure is normally kept at a low level of about 4 to 7 kg / cm 2 G and kept low. . At this time, the supply route of the undiluted solution composed of the slurry containing the particulate solid substance and the discharge route of the filtrate are determined by the first method.
This is the same as in the first embodiment of the invention. After this normal filtration step, the compressed fluid is passed through the cake compressed fluid introduction pipes (17) connected to each filter plate (5) and the header (16) connected to these introduction pipes (17). A compressed fluid such as compressed air or compressed water from the supply pipe (15) is introduced into the filter chamber, the cake is compressed, and the filter chamber is densely filled with cake. The compressed pressure by the compressed fluid is measured by a pressure gauge in the middle of the compressed fluid introduction pipe (17).
Measured according to (34), and the squeezing pressure is set to 5 to 20 kg / cm ² G.

At the same time, blow air is blown onto the densely packed cake at a high pressure to remove moisture in the cake. The blowing of the blow air at this time is performed from the second filtrate outlet (12) of each filter plate (5) as in the case of the first embodiment of the first invention, and the compressed filtrate and the blow filtrate are blown. The discharge is performed from the first filtrate outlet (11) of each filter plate (5) through the first filtrate discharge pipe (21) and the bypass pipe (25), as in the case of the first embodiment of the first invention. The compressed filtrate and the blow filtrate are discharged from a discharge pipe (27). Therefore, the opening and closing operation of each valve at this time is the same as that of the first embodiment of the first invention, and the automatic control valve (CV2) in the middle of the blow filtrate discharge pipe (27).
, And manual valve (MV) for adjusting the opening of the bypass pipe (25)
Open all remaining automatic control valves (CV1) and automatic control valves
(CV3) to (CV6) are closed.

Next, FIG. 2 shows a second embodiment of the first and second inventions.
Fig. 3 shows a flow sheet of the embodiment, which is almost the same as the flow sheet of the first embodiment of the two inventions shown in Fig. 1 described above, except for the difference of the second filtrate discharge pipe (22). The tip is connected to the connection point (A) near the connection point (B1) of the bypass pipe (25).
In 5), the point connected to the tip of the first filtrate discharge pipe (21) and the tip of the third filtrate discharge pipe (23) are connected to the fourth filtrate discharge pipe upstream of the automatic control valve (CV4). (24) is connected at a connection point (A3) to a portion near the start end, and thereby, the automatic control valves (CV3) and (CV6) are omitted.

The second embodiment of the first invention (high-pressure filling of slurry + air blow) will be described in detail with reference to the flow sheet of FIG.

First, in the filtration step, the filling pressure of the slurry is kept high, and the cake is densely filled in the filtration chamber.
At this time, the filtrate is supplied from the first to fourth filtrate outlets (11), (12), (13), (14) at the four corners of each filter plate (5) through the first to fourth filtrate discharge pipes (21), (2).
2) Discharge through (23) and (24). Therefore, the filtrate discharge pipe (2
6) Open the automatic control valve (CV1) on the way and open the blow filtrate discharge pipe (2
7) Close the automatic control valve (CV2) on the way. Further, the automatic control valve (CV4) of the fourth filtrate discharge pipe (24) and the first filtrate discharge pipe (2
The automatic control valve (CV) at the filtrate discharge pipe section (21a) near the tip of 1)
5) Open and open the manual valve (M
V) is also open. Also, the blow valve (BV) in the middle of the blow air supply pipe (28) is closed.

After the cake is densely filled in the filter chamber in this way, blow air is blown at a high pressure to the densely packed cake to remove moisture in the cake. At this time, the blown air is blown to the third filtrate outlet (13) of each filter plate (5) and to the fourth filtrate outlet.
It is carried out from two places at the filtrate outlet (14).

That is, the blow air is supplied from the blow air supply pipe (28) to the third filtrate discharge pipe (23) connected at the connection point (A4).
And the third filtrate outlet (13) through the start end of the fourth filtrate discharge pipe (24) connected at the connection point (A3) from the pipe (23).
And, it is introduced into the filtration chamber from the fourth filtrate outlet (14).

The blow filtrate is discharged from the first filtrate outlet (11) and the second filtrate outlet (12) of each filter plate (5) by a first filtrate discharge pipe.
(21) and a second filtrate discharge pipe (22) and a bypass pipe (25), and are discharged from a blow filtrate discharge pipe (27).

For this purpose, the automatic control valve (CV2) on the way of the blow filtrate discharge pipe (27) is opened, and the automatic control valve (CV1) on the way of the filtrate discharge pipe (26) is closed. In addition, open the opening adjustment manual valve (MV) in the middle of the bypass pipe (25), and open all remaining automatic control valves (CV4).
(CV5) is closed.

Next, based on the above flow sheet, a second embodiment of the second invention (normal filling of slurry + cake pressing + air blow) will be described in detail.

First, the filtration step is almost the same as that of the second embodiment of the first invention, except that the slurry filling pressure is usually about 4 to 7 kg / cm ² G and is kept low. I do. At this time, the supply route of the undiluted solution composed of the slurry containing the particulate solid substance and the discharge route of the filtrate are determined by the first method.
This is the same as in the second embodiment of the invention. Then, after this normal filtration step, a compressed fluid such as compressed air or compressed water from the compressed fluid supply pipe (15) is introduced into the filter chamber, the cake is compressed, and the cake is densely filled in the filter chamber. .

At the same time, blow air is blown onto the densely packed cake at a high pressure to remove moisture in the cake. The blowing of the blow air at this time is carried out at the third filtrate outlet (13) and the fourth filtrate outlet (14) of each filter plate (5) in the same manner as in the second embodiment of the first invention. The pressurized filtrate and the blow filtrate are discharged from two places, and are discharged according to the second aspect of the first invention.
As in the case of the embodiment, the first filtrate outlet (1) of each filter plate (5) is used.
1) and a second filtrate outlet (12) are passed through a first filtrate discharge pipe (21), a second filtrate discharge pipe (22), and a bypass pipe (25), and are discharged from a blow filtrate discharge pipe (27). Therefore, the opening / closing operation of each valve at this time is the same as that of the second embodiment of the first invention, and the automatic control valve (CV2) and the bypass pipe (25) on the way of the blow filtrate discharge pipe (27). The opening degree adjustment manual valve (MV) in the middle is opened, and the remaining automatic adjustment valves (CV1), (CV4) and (CV5) are closed.

Next, FIG. 3 shows a third embodiment of the first and second inventions.
Fig. 3 shows a flow sheet of the embodiment, which is almost the same as the flow sheet of the first embodiment of the two inventions shown in Fig. 1 described above, except for the difference of the second filtrate discharge pipe (22). The tip is connected to the middle part of the fourth filtrate discharge pipe (24) at the connection point (A7), and the second filtrate discharge pipe (22) is connected to the bypass pipe.
(25) is connected at connection points (B3) and (B4), and both connection points
An automatic control valve (CV5) is interposed in one filtrate discharge pipe part (22a) between (B3) and (B4), and an opening adjustment manual valve (MV) is interposed in the middle of the other bypass pipe (25). And a second filtrate discharge pipe
The point where the pressure gauge (32) is provided at the bypass pipe connection point (B3) of (22), and the tip of the third filtrate discharge pipe (23) is connected to the portion near the start end of the first filtrate discharge pipe (21). The point connected at the point (A6) is that an automatic control valve (CV3) is interposed in the middle of the first filtrate discharge pipe (21) downstream of the connection point (A6).

The third embodiment of the first invention (high-pressure filling of slurry + air blow) will be described in detail with reference to the flow sheet of FIG.

First, in the filtration step, the filling pressure of the slurry is kept high, and the cake is densely filled in the filtration chamber.
At this time, the filtrate is supplied from the first to fourth filtrate outlets (11), (12), (13), (14) at the four corners of each filter plate (5) through the first to fourth filtrate discharge pipes (21), (2).
2) Discharge through (23) and (24). Therefore, the filtrate discharge pipe (2
6) Open the automatic control valve (CV1) on the way and open the blow filtrate discharge pipe (2
7) Close the automatic control valve (CV2) on the way. Further, the automatic control valve (CV4) of the fourth filtrate discharge pipe (24) and the first filtrate discharge pipe (2
The automatic control valve (CV) at the filtrate discharge pipe section (21a) near the tip of 1)
5) Open and open the manual valve (M
V) is also open. Also, the blow valve (BV) in the middle of the blow air supply pipe (28) is closed.

After the filter chamber is densely filled with the cake in this way, blow air is blown at a high pressure to the densely packed cake to remove moisture in the cake. At this time, the blowing of the blow air is performed from the first filtrate outlet (11) of each filter plate (5).

That is, blow air is supplied from the blow air supply pipe (28) to the third filtrate discharge pipe (23) connected at the connection point (A4).
And a first filtrate outlet (11) through a first filtrate outlet pipe (21) connected at a connection point (A6) from the pipe (23) to the filtration chamber.

The blow filtrate is discharged from the second filtrate outlet (12) of each filter plate (5) through the second filtrate discharge pipe (22) and the bypass pipe (25), and discharged from the blow filtrate discharge pipe (27). I do.

For this purpose, the automatic control valve (CV2) on the way of the blow filtrate discharge pipe (27) is opened, and the automatic control valve (CV1) on the way of the filtrate discharge pipe (26) is closed. Also, open the opening adjustment manual valve (MV) in the middle of the bypass pipe (25), and open all remaining automatic control valves (CV3) to
(CV6) is closed.

The pressure of the blow air in the filter chamber is adjusted by adjusting the opening of the manual valve (MV) for adjusting the opening in the middle of the bypass pipe (25), so that the discharge amount of the blow filtrate is increased as much as possible. Is what you do.

Next, based on the flow sheet of FIG.
A third embodiment of the second invention (normal filling of slurry + cake pressing + air blow) will be described in detail.

First, the filtration step is almost the same as that of the first invention, except that the slurry filling pressure is 4
Approximately 7 kg / cm ² G, which is kept low. At this time, the supply route of the undiluted solution composed of the slurry containing the particulate solid substance and the discharge route of the filtrate are the same as those in the third embodiment of the first invention. After this normal filtration step, the cake pressurized fluid introduction pipe connected to each filter plate (5)
(17) and headers (16) connected to these introduction pipes (17)
, A compressed fluid such as compressed air or compressed water from a compressed fluid supply pipe (15) is introduced into the filter chamber, the cake is compressed, and the filter chamber is densely filled with the cake.

At the same time, blow air is blown onto the densely packed cake at a high pressure to remove water from the cake. The blowing of the blow air at this time is performed from the first filtrate outlet (11) of each filter plate (5) in the same manner as in the third embodiment of the first invention, and the compressed filtrate and the blow filtrate are blown. The discharge is performed from the second filtrate outlet (12) of each filter plate (5) through the second filtrate discharge pipe (22) and the bypass pipe (25), as in the case of the third embodiment of the first invention. The compressed filtrate and the blow filtrate are discharged from a discharge pipe (27). Therefore, the opening and closing operation of each valve at this time is the same as that of the third embodiment of the first invention, and the automatic control valve (CV2) in the middle of the blow filtrate discharge pipe (27).
, And manual valve (MV) for adjusting the opening of the bypass pipe (25)
Open all remaining automatic control valves (CV1) and automatic control valves
(CV3) to (CV6) are closed.

[0059]

Next, an embodiment of the present invention will be described.

Examples 1 and 2 First, a calcium carbonate slurry having a concentration of 8% by weight was prepared as a stock solution to be filtered, and a filter press having a flow sheet shown in FIG. 1 was used. The method of the present invention was carried out based on the first embodiment of the present invention.

Table 1 below shows the solid content of the slurry used, the slurry filtration method, the filling pressure of the slurry (kg / cm ² ), the blow pressure (kg / cm ² ), and the amount of air consumed (Nl / kg (DS)). ), Cake moisture (% by weight), and the results of the presence or absence of thixotropic property are collectively described.

The column of the slurry filtration method in Table 1 is described as follows.

A: High-pressure filling of slurry + air blow (first invention) B: Normal filling of slurry + cake pressing + air blowing (second invention) C: Normal filling of slurry + cake pressing (conventional example) And 4 First Embodiment of the Second Invention (Normal Filling of Slurry + Cake Squeezing + Air Blow) Using a Calcium Carbonate Slurry as a Stock Solution as in Example 1 and Using a Filter Press Having the Flow Sheet of FIG. The method of the present invention was implemented based on

Similarly, in Table 1 below, the slurry solid content, the slurry filtration method (ie, B), the pressing pressure (kg / cm ² ) in addition to the filling pressure of the slurry are described, and the blowing pressure and the air consumption are shown. , Cake moisture, and the results for the presence or absence of thixotropic properties are summarized.

Comparative Examples 1 and 2 For comparison, a calcium carbonate slurry was prepared as a stock solution in the same manner as in Example 1 above, and the conventional method (normal filling of slurry + cake pressing) was carried out using a conventional filter press. .

Similarly, Table 1 below summarizes the results of the solid content of the slurry used, the slurry filtration method (ie, C), the filling pressure of the slurry, the pressing pressure, the cake moisture, and the presence or absence of thixotropic properties.

Example 5 A gypsum slurry having a concentration of 4% by weight was prepared as a stock solution to be filtered, and a gypsum slurry of the first invention (high-pressure filling of slurry + air blow) was prepared using a filter press having a flow sheet shown in FIG. The method of the present invention was implemented according to one embodiment.

Table 1 below summarizes the results of the slurry solids used, the slurry filtration method (ie, A), the slurry filling pressure, blow pressure, air consumption, cake moisture, and the presence or absence of thixotropic properties.

Example 6 A gypsum slurry was prepared as a stock solution in the same manner as in Example 5 above, and the second press of the second invention (normal filling of slurry + cake pressing + air blowing) was performed using a filter press having a flow sheet shown in FIG. The method of the present invention was implemented according to one embodiment.

Similarly, in Table 1 below, the slurry solids used, the slurry filtration method (ie, B), the pressing pressure in addition to the filling pressure of the slurry are described, and the blowing pressure, the amount of consumed air, the cake moisture, and the thixotropic The results on the presence or absence of sex are summarized and described.

Comparative Examples 3 and 4 For comparison, a gypsum slurry was prepared as a stock solution in the same manner as in Example 5 above, and a conventional method (normal filling of slurry + cake pressing) was carried out using a conventional filter press.

Similarly, Table 1 below summarizes the results of the slurry solids used, slurry filtration method (ie, C), slurry filling pressure, squeezing pressure, cake moisture, and the presence or absence of thixotropic properties.

[0073]

[Table 1] As is clear from the results in Table 1, according to the embodiment of the present invention, the cake in the filter chamber can be densely packed, the excess voids in the cake are reduced, and the water content of the cake is significantly reduced. As a result, the thixotropy of the cake was remarkably eliminated. On the other hand, in the conventional method, the cake has a large amount of water and has a thixotropic property. By repeatedly receiving physical pressure, it softens and fluidizes, and this softening phenomena makes it impossible to transport or supply the cake. This may cause the workability of the cake treatment to deteriorate.

When the calcium carbonate slurry was used as the stock solution by the method of the present invention, the final water content of the cake was about 38% by weight or less, and there was no thixotropic property, and the gypsum slurry was used as the stock solution. In this case, it was found that the final moisture content of the cake was approximately 34% by weight or less and there was no thixotropic property.

[0075]

According to the filtration method using a filter press of the present invention, according to the first aspect of the present invention, when a slurry containing fine solid particles is filtered by a filter press, the slurry is supplied into a filter chamber. The pressure is increased, the cake is densely packed in the filter chamber, and air is blown at a high pressure to the densely packed cake to remove moisture in the cake. In the invention, after the slurry is supplied into the filter chamber to form a cake, the cake is squeezed and densely filled, and air is blown to the densely packed cake at a high pressure to remove moisture in the cake. In any of the methods, when filtering the slurry containing the fine solid particles, the filling pressure of the cake generated from the slurry supplied into the filtration chamber is increased, and A key closely, to minimize the extra voids in the cake, and by blowing air (blow) at high pressure cake in this state,
The water content of the cake can be reduced, and the thixotropy of the cake can be remarkably eliminated, thereby preventing the softening and fluidization of the cake during the conveyance process of the cake or the storage stage by the hopper. Thus, there is an effect that no trouble is caused in the cake processing operation, the operation is simple, no special equipment is required, and the cost is reduced.

[Brief description of the drawings]

FIG. 1 is a filter press flow sheet for explaining a first embodiment of the first and second inventions of the present invention.

FIG. 2 is a flow sheet of a filter press illustrating the second embodiment.

FIG. 3 is a flow sheet of a filter press illustrating the third embodiment.

FIG. 4 is a schematic side view of an entire filter press for implementing the method of the present invention.

[Explanation of symbols]

 Reference Signs List 5 filter plate 10 undiluted solution inlet 11 first filtrate outlet 12 second filtrate outlet 13 third filtrate outlet 14 fourth filtrate outlet 15 compressed fluid supply pipe 20 undiluted solution supply pipe 21 first filtrate discharge pipe 22 second filtrate discharge pipe 23 3 Filtrate discharge pipe 24 Fourth filtrate discharge pipe 25 Bypass pipe 26 Filtrate discharge pipe 27 Compressed filtrate and / or blow filtrate discharge pipe 28 Blow air supply pipe

Claims (2)

[Claims] When a slurry containing fine solid particles is filtered by a filter press, the supply pressure of the slurry into the filter chamber is increased, and the cake is densely filled in the filter chamber. A high-pressure spray to remove water from the cake. 2. A slurry containing fine solid particles is filtered by a filter press, a slurry is supplied into a filtration chamber to form a cake, and then the cake is pressed and densely filled, and is blown into a densely packed cake. A filtration method using a filter press, wherein air is blown at a high pressure to remove moisture in the cake.