JP4009820B2 - Method for producing dispersion of granular silica and dilute sulfuric acid - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a dispersion of granular silica and dilute sulfuric acid .
[0002]
[Prior art]
Conventionally, as a liquid holding method for a sealed lead-acid battery, there is a so-called retainer type in which an electrolytic solution is impregnated and held in a mat-like separator made of fine glass fibers. Although this type of battery has a good initial capacity, there is a problem in that the separator is weak in the force of pressing the active material, and the life performance is lowered early due to deterioration of the active material, lattice elongation, and the like.
[0003]
For this reason, in recent years, a granular silica battery has been proposed in which granular silica is densely packed between the electrode plates and around the electrode plate group, and the electrolyte is held by the electrode plates, the separator and the granular silica. Thereby, since the silica closely packed in the battery presses the electrode plate from all directions, the life performance is remarkably improved.
[0004]
For example, Japanese Patent Laid-Open No. 3-252063 discloses a sealed lead-acid battery in which a battery is filled with silica powder having a diameter of 10 to 500 μm, and an electrolyte is held in an electrode plate, a separator and silica powder. Are listed. Moreover, silica powder is a very inexpensive material compared to conventional glass fiber separators, and can be said to be an important material that enables a battery that is inexpensive and has excellent performance.
[0005]
[Problems to be solved by the invention]
Since the silica powder used for the electrolyte solution holding material of the battery needs to hold as much electrolyte solution as possible, porous silica is used. If the silica is made porous, the fluidity of the silica is deteriorated, and the filling of the battery needs to give a strong vibration by a vibrator. Further, such silica powder has a high specific surface area, and in order to inject an electrolyte, a reduced pressure injection is required in which the inside of the battery is reduced by a vacuum pump. Accordingly, there are disadvantages that the cost of equipment such as a vibrator and a vacuum injection device is high, and that it takes a considerable amount of time to fill and inject granules, resulting in low productivity and high manufacturing costs. For this reason, in order to make vibration filling and vacuum injection into one process, granular silica and dilute sulfuric acid are dispersed in a non-injection battery using a battery case with a hole on the side or bottom and a filter covering it. There is a method in which only the excess electrolyte solution is discharged from a discharge port (Japanese Patent Laid-Open No. 7-122288). Even in this method , the discharge rate of the excess electrolyte may be remarkably slow, and the manufacturing cost may be increased. In addition, in a battery with a slow discharge rate, the amount of dilute sulfuric acid near the discharge port is appropriate, but there is a bias in the distribution of dilute sulfuric acid, such as too much dilute sulfuric acid near the injection port, which may adversely affect battery performance. there were. Furthermore, in the step of preparing a solution in which granular silica is dispersed in dilute sulfuric acid, when the granular silica adheres to the inner surface of the dispersion tank, a solution having a stable mixing ratio cannot be obtained, and the above problem tends to be promoted. was there.
[0006]
The problem to be solved by the present invention is to provide a method for producing a dispersion in which granular silica and dilute sulfuric acid are uniformly dispersed in order to eliminate the above-described problems.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the method for producing a dispersion of granular silica and dilute sulfuric acid according to claim 1 is a dispersion tank (5) for producing a dispersion of granular silica and dilute sulfuric acid, An inner lid (8) that divides the inside of the dispersing tank into an upper chamber and a lower chamber, and a gap provided between the outer peripheral wall of the inner lid and the inner wall surface of the dispersing tank, which communicates the upper chamber and the lower chamber A rotary blade (6) arranged in the lower chamber, a first inlet (1) communicating with the lower chamber, and a second inlet (2) communicating with the upper chamber, The dilute sulfuric acid charged from (2) is configured to reach the lower chamber through the gap. First, dilute sulfuric acid is charged from the second charging port (2), and then the first charging port. Add granular silica from (1), mix granular silica and dilute sulfuric acid with rotating blade (6), and add dilute sulfuric acid from the second inlet (2). Characterized by mixing with wings (6).
[0008]
DETAILED DESCRIPTION OF THE INVENTION
[0009]
【Example】
[0010]
A dispersion using granular silica having an average particle size of about 60 μm (measured by a Coulter counter method) and dilute sulfuric acid having a specific gravity of 1.31 (20 ° C.) will be described.
[0011]
FIG. 1 is a view showing a dispersion tank used in the present invention . The dispersion tank 5 includes a middle lid 8 that divides the inside of the dispersion tank into an upper chamber and a lower chamber, and a gap provided between the outer peripheral wall of the middle lid and the inner wall surface of the dispersion tank. , A rotary blade 6 disposed in the lower chamber, a first inlet 1 that communicates with the lower chamber, and a second inlet 2 that communicates with the upper chamber. The introduced diluted sulfuric acid is configured to reach the lower chamber through the gap. First, 80 to 90% of the required amount of dilute sulfuric acid is charged from the second inlet 2 through the valve 4 and then the entire required amount of granular silica is passed through the valve 3 from the first inlet 1. After passing through the opening 9 of the lid 8, the rotary blade 6 is rotated to mix and disperse.
[0012]
In this case a part of the granules silica adheres to the dispersion vessel wall surface soaring. Therefore, finally, the remaining amount of dilute sulfuric acid is introduced from the second introduction port 2 through the valve 4 through the end of the inner lid 8 along the inner surface of the dispersion tank, and the adhering granular silica is washed away before the rotary blade 6 By rotating and mixing, it was possible to obtain a solution in which the granular silica was uniformly dispersed without adhering to the dispersing tank.
[0013]
Thereafter, this dispersion solution is injected into the battery through the valve 7. On the other hand, as shown in FIG. 2, when the conventional equipment without an inner lid is used, a part of the granular silica remains adhered to the inner surface of the dispersion tank, and a dispersion solution having an appropriate mixing ratio cannot be obtained.
[0014]
In this example, the flat plate was installed horizontally as the inner lid, but even if it is convex rather than flat, if dilute sulfuric acid falls along the inner surface of the dispersion tank from the end of the inner lid. Any shape may be used, and the same effect is exhibited.
[0015]
【The invention's effect】
As described above , according to the present invention , a dispersion having a stable mixing ratio of granular silica and dilute sulfuric acid can be obtained, and the productivity is excellent, and its industrial value is extremely large.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a dispersion tank used in the present invention. FIG. 2 is a conventional dispersion tank .
1 First inlet 2 Second inlet 3 Valve 4 Valve 5 Dispersion tank 6 Rotary blade 7 Valve 8 Inner lid 9 Opening part

Claims (1)

A dispersion tank (5) for producing a dispersion of granular silica and dilute sulfuric acid, an inner lid (8) for partitioning the interior of the dispersion tank into an upper chamber and a lower chamber, an outer peripheral wall of the inner lid, and a dispersion tank A gap provided between the inner wall surface and communicating between the upper chamber and the lower chamber, a rotating blade (6) disposed in the lower chamber, and a first input port (1) communicating with the lower chamber And a second inlet (2) communicating with the upper chamber, and the dilute sulfuric acid introduced from the second inlet (2) is configured to reach the lower chamber through the gap. ,
First, dilute sulfuric acid is charged from the second inlet (2), then granular silica is charged from the first inlet (1), and the granular silica and dilute sulfuric acid are mixed with the rotary blade (6). A method for producing a dispersion of granular silica and dilute sulfuric acid, wherein dilute sulfuric acid is additionally added from the second input port (2) and mixed by a rotary blade (6).

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