JP2000229315A - Production of decorative inorganic cement plate material and device thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively reutilize waste water without marring the swelling properties of clay substance added to improve patterning properties by pressing in a sheet-manufacturing method in which a large amounts of waste water are generated. SOLUTION: In the method for producing the decorative inorganic cement plate material in which cement material for a surface layer containing a clayey material is supplied on the surface of a cement plate produced by a sheet- manufacturing method and pressed after dehydration and uneven patterns are formed, prior to reutilization of waste water generated in the producing process, calcium ions contained in waste water W are deposited as calcium carbonate and moreover waste water is reutilized as water for a raw material as it is without removing calcium carbonate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing a decorative inorganic cement board, and more particularly, to a method for producing a decorative inorganic cement board by a papermaking method, which effectively utilizes wastewater generated during the manufacturing process. The present invention relates to a method and an apparatus for manufacturing a cement board.

[0002]

2. Description of the Related Art Conventionally, a papermaking method is known as a method for producing a fiber-reinforced cement board. In this paper making method, a round mesh cylinder is immersed in a cement milk tank to make a cement material, and the made cement material layer is transferred to a felt belt to form a seed film, which is sequentially wound around a making roll. Laminate to a predetermined thickness, then cut and stretched flat, press to form a round mesh paper making method to give a plate material with an uneven pattern on the surface, or supply a slurry of cement slurry on a dehydration belt in layers, suction dewater A flow-on papermaking method and the like are known in which a plate is made, a cement slurry for a surface layer is supplied to the surface of the cement plate, and then pressed to form a plate with an uneven pattern on the surface.

[0003]

By the way, in the above-mentioned papermaking method, a large amount of water is used when preparing a cement slurry, and a large amount of wastewater is generated during a dewatering step or a pressing step in a manufacturing process. Cannot be drained as it is because it contains a large amount of alkaline impurities derived from the cement component.

[0004] In view of such problems, it has been proposed and implemented to collect wastewater, reuse it as added water for cement slurry, and reduce the wastewater as much as possible. A large amount of calcium ions eluted from the cement component is contained, and this calcium ion sometimes hinders the formation of a deeply carved uneven pattern on the product surface.

[0005] That is, when a deeply carved pattern is applied to a cement board obtained by a papermaking method, a surface cement material containing a clay-like material is supplied to the surface of the cement board in order to facilitate the deep carved pattern. Pressing into this layer has been performed. This viscosity is imparted by water molecules easily penetrating between layers of a clay-like material having sodium ions between layers in a layered structure, thereby giving swelling property, and the viscosity of the clay is exerted by the swelling property. If the water added to the substance contains a large amount of calcium ions, the sodium ions are positively replaced by calcium ions, and the calcium ions have a strong bond between the layers, so that the penetration of water molecules is inhibited. As a result, the swelling property of the clay is lost, the viscosity is also lost, and it becomes difficult to form a deeply carved press pattern.

The present invention provides a method and an apparatus for producing a decorative inorganic cement board which can effectively reuse drainage without impairing the swellability of the surface layer in a papermaking method which solves the above problem and generates a large amount of drainage. It was made for the purpose of providing.

[0007]

In order to achieve the above object, a method for producing a decorative inorganic cement board according to claim 1 comprises:
On the surface of the cement board manufactured by the papermaking method, a surface cement material containing a clay material is supplied, and after the dehydration, a method of manufacturing a decorative inorganic cement board material in which an uneven pattern is formed by pressing and pressing,
Prior to reuse of wastewater generated during the manufacturing process, calcium ions contained in the wastewater are precipitated as calcium carbonate, and the calcium carbonate is reused as raw water without removing the calcium carbonate.

According to the present invention, the calcium ions in the wastewater are precipitated as calcium carbonate, so that they do not affect the sodium ions of the clay molecules and the viscosity of the clay material is not impaired. In addition, the calcium carbonate precipitate does not have any adverse effect on the bonding strength of the cement composition, and therefore does not need to be removed.

According to a second aspect of the present invention, there is provided an apparatus for producing an inorganic cement board by a papermaking method, wherein an alkali carbonate is provided in a water collecting tank for overflow water from a papermaking vat, dewatering, and drainage generated during pressing. And a stirring device, and a pump device for circulating the treated water from the water collecting tank to the vat for papermaking is provided.

In the above description, examples of the alkali carbonate include sodium carbonate (Na2CO3) and potassium carbonate (K2C).
O3) and the like. According to a third aspect of the present invention, the water collecting tank for drainage in the above apparatus is provided with a carbon dioxide gas injection pipe instead of the alkali carbonate addition device and the stirring device.
In this case, since the calcium ions in the wastewater are precipitated by the carbon dioxide gas, the wastewater is circulated and agitated by jetting the gas, so that a stirrer is unnecessary.

[0011]

Next, an embodiment of the present invention will be described. Embodiment 1 FIG. 1 is a conceptual diagram of an apparatus for manufacturing a decorative inorganic cement board according to Embodiment 1 of the present invention.

An apparatus 1 for producing a decorative inorganic cement board comprises a flow box 3 for supplying a fiber reinforced cement compounding material 2.
And a dewatering belt 4 which supplies the material 2 in a layered form and performs suction dehydration during the transfer, and a dewatered fiber-reinforced cement tank 2
a supply device 6 for supplying a decorative cement material 5 containing a clay substance onto the decorative cement layer 5a; a press plate 7 for performing a deeply carved uneven pattern press on the decorative cement layer 5a; A collecting gutter 9 and a collecting tank 10 for drainage generated in the process line 7 are attached to the process line.

The water collecting tank 10 is provided with a storage tank 12 for storing an alkali carbonate 11, which communicates with a supply device 13. A stirring device 14 is provided in the tank 10. Examples of the alkali carbonate include sodium carbonate (Na2C
O3), potassium carbonate (K2CO3) and the like. next,
When a decorative inorganic cement board is manufactured by the above-described apparatus 1, a fiber-reinforced cement board is dewatered and formed by a so-called flow-on molding method, and a decorative cement material 5
Is formed and a concavo-convex pattern is formed by the press plate 7. Drainage generated in this manufacturing process is collected in the water collecting tank 10 through the water collecting gutter 9.

In the water collecting tank 10, a calcium carbonate salt 11 is supplied from a storage tank 12 through a supply device 13 such as a pump or a hopper, and is stirred in the tank 10 with drainage collected by a stirring device 14. At this time, the calcium ions contained in the waste water react with the calcium carbonate salt to precipitate as calcium carbonate, and the calcium ion concentration is reduced.

This waste water is used as an additional raw material water for the cement slurry via the pump 10a. In this case, even in the wastewater generated in the cement plate manufacturing process, since the calcium ions in the wastewater are precipitated as calcium carbonate, the swelling performance of clay substances such as sodium-based bentonite is not hindered, and the raw material water is not affected. Can be used as well. Embodiment 2 FIG. 2 is a conceptual diagram of an apparatus for manufacturing a decorative inorganic cement board according to Embodiment 2 of the present invention.

In the second embodiment, members denoted by the same reference numerals as those in FIG. 1 indicate the same or corresponding members.
Detailed description is omitted. In FIG. 2, the manufacturing apparatus for the decorative inorganic cement plate material includes the storage tank 12 according to the first embodiment.
, A carbon dioxide gas cylinder 12 is provided, and instead of the supply device 13 and the stirring device 14, a carbon dioxide gas diffuser 15 is provided in the water collecting tank 10.

In the case of the apparatus according to the second embodiment, the collected wastewater is aerated with carbon dioxide gas from the air diffuser 15 in the water collecting tank 10. Calcium ions in the wastewater are precipitated as calcium carbonate by the carbon dioxide gas, and the concentration of calcium ions in the wastewater is reduced. Therefore, also in the case of the second embodiment, the wastewater can be sufficiently reused as raw water without hindering the swelling performance of the clay material.

When the carbon dioxide gas in the water collecting tank 10 is aerated,
Since there is an aeration effect by the air diffuser 15, the waste water is well stirred, and calcium carbonate can be deposited without the need for a stirring device. In the above embodiment, the case of the flow-on molding has been described.

Example 1 Using the apparatus shown in FIG. 1, sodium carbonate was used as an alkali carbonate, and the wastewater was treated so that the final concentration of calcium ions in the wastewater was 100 ppm. 40% by weight of cement, 40% by weight of silica sand, pulp fiber
A commonly used cement composition of 10% by weight and 10% by weight of lightweight aggregate was prepared, and a cement slurry having a slurry concentration of 25% was prepared.

This cement slurry is supplied on an endless felt belt provided with a suction dewatering device in a layer having a thickness of 30 to 50 mm, and is conveyed while being suctioned and dewatered. , On the base cement layer,
The blending material was the same as that of the slurry, and 12.5% by weight of bentonite was added to reduce the total amount of the pulp fiber and the lightweight aggregate by 12.5% by weight. % Of the slurry was supplied in the form of a layer having a thickness of 5 mm.

The cut formed plate 5 is transferred to a press platen 6.
It was compression-pressed at a pressing pressure of 10 MPa for 3 seconds with a press plate 6 having an uneven pattern of 3 mm in depth and a brick joint shape of 10 cm × 5 cm. After pressing, the molded plate 5 was naturally cured for 24 hours. [Example 2] In the wastewater treatment in Example 1, the wastewater was treated so that the final concentration of calcium ions became 10 ppm. [Comparative Example 1] The same apparatus as in Example 1 was used, except that the collected wastewater was not subjected to any calcium ion treatment and the same wastewater (white water) was used to produce the same decorative inorganic cement board as in Example 1. Manufactured. [Comparative Example 2] The same apparatus as in Example 1 was used, except that the water used was all tap water without using wastewater.
In the same manner as in the above, a decorative inorganic cement board was produced.

The decorative cement plates of Example 1 and Comparative Examples 1 and 2 were subjected to autoclave curing, and the plate materials were evaluated for formability and bending strength. The results are shown in Table 1 below.

[Table 1] In Table 1, the shaping property evaluation is a result of a visual test for the presence or absence of cracks from the convex surface to the corners of the uneven pattern.
◎ indicates no cracks, は indicates minute cracks, and X indicates the presence of many cracks.

As is apparent from Table 1, the calcium ion concentration in the working water of the working example was much lower than that of the comparative example 1 using white water, so that the viscosity of the clay material was kept good and the comparative example 2 A deeply carved uneven pattern almost inferior to the case of using tap water was formed. On the other hand, in the case of Comparative Example 1, the viscosity of the clay material was lost due to the high calcium ion concentration, and many cracks were observed.

[0024]

As described above, according to the present invention, when a decorative inorganic cement board is formed by a papermaking method, it is possible to sufficiently form a deeply carved uneven pattern even by using drainage. Discharge of highly alkaline wastewater can be prevented. In addition, since the precipitated calcium carbonate is added to the molded article without removing it, there is no need to provide a calcium carbonate removing facility, and the implementation is easy.

Further, since the use of new water can be refrained, effective use of water can be achieved and resources can be protected.

[Brief description of the drawings]

FIG. 1 is a side view of an apparatus for manufacturing a decorative inorganic cement board according to a first embodiment.

FIG. 2 is a side view of an apparatus for manufacturing a decorative inorganic cement board according to a second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Manufacturing apparatus of cosmetic inorganic cement board 2 Fiber reinforced cement compounding material 2a Fiber reinforced cement layer 3 Flow box 4 Dehydration belt 5 Dehydration suction box 6a Decorative cement material 7 Supply device 8 Press board 9 Water collecting gutter 10 Water collecting tank 11 Calcium carbonate 12 storage tank 13 supply device 14 stirrer 15 diffuser

Claims (3)

[Claims] 1. A method for producing a decorative inorganic cement board material in which a cement material for a surface layer containing a clay material is supplied to the surface of a cement board produced by a papermaking method, and is pressed after dewatering to give an uneven pattern. When the resulting wastewater is reused as circulating water, calcium ions contained in the wastewater are precipitated as calcium carbonate before reuse,
In addition, a method for producing a decorative inorganic cement plate material, wherein the calcium carbonate is reused as raw water without removing it. 2. An apparatus for producing an inorganic cement board by a papermaking method, wherein a water collecting tank for overflow water from a papermaking vat, dewatering, and drainage generated during pressing is provided with a device for adding an alkali carbonate and a stirring device. An apparatus for producing a decorative inorganic cement plate material, comprising a pump device for circulating treated water from a water collecting tank to the vat for papermaking. 3. The apparatus for manufacturing a decorative inorganic cement board according to claim 2, wherein an injection pipe for carbon dioxide gas is provided in the drainage collecting tank in place of the alkali carbonate addition apparatus and the stirring apparatus.