JP3280537B2 - Pulp treatment method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating pulp blended as a reinforcing material into an inorganic plate used as a building material such as a tile or an outer wall material.

[0002]

2. Description of the Related Art Conventionally, an inorganic plate is formed by blending pulp as a reinforcing material with cement, and this inorganic plate is used as a building material. However, the inorganic plate as a building material has a high fire protection performance. It is essential that the fire prevention performance is specified by tests such as a surface test and a base material test (Ministry of Construction No. 1828). The above-mentioned base material test is performed by using a test block of a predetermined size formed of an inorganic plate for 75 times.
The furnace is placed in an electric furnace adjusted to 0 ° C., and then the temperature change in the furnace for 20 minutes is measured. If the temperature rise in the furnace is 50 ° C. or less (the furnace temperature is 800 ° C. or less) For example, the inorganic plate satisfies the acceptance criteria of the base material test and is said to have high fire prevention performance.

In other words, if the temperature exceeds 800 ° C. (two-dot chain line in FIG. 2) even within a heating time of 20 minutes as shown by the heat generation characteristic curve of the solid line in FIG. 2, the inorganic plate fails the substrate test. If the temperature does not exceed 800 ° C. within a heating time of 20 minutes as shown by a heat generation characteristic curve indicated by a dotted line in FIG. 2, the inorganic plate passes the base material test.

[0004]

However, the pulp conventionally blended in the inorganic plate has a problem that the calorific value is large and the fire prevention performance of the inorganic plate cannot be enhanced. For this reason, the conventional inorganic plate is formed with a small amount of pulp in order to enhance the fire protection performance, and as a result, the mechanical strength such as the strength at the time of nailing and the strength at the time of bending of the inorganic plate decreases. In addition, in the conventional inorganic plate, the thickness or the shape of the inorganic plate is increased so as to obtain mechanical strength, and the design of the thickness and the shape of the inorganic plate is limited.

[0005] The present invention has been made in view of the above points, and has as its object to provide a method for treating pulp that can reduce the calorific value of an inorganic plate in a substrate test.

[0006]

The method for treating pulp according to the present invention is characterized in that pulp is beaten in treated water containing inorganic ions. In the present invention, the solid content concentration in 0.5～4.0Wt%, Ru a waste solution generated in the papermaking process of slurry containing the cement as the treated water.

In the present invention, it is preferable that the beating degree of the pulp is not less than 60 csf and not more than 500 csf in Canadian standard freeness. The pulp of the present invention can be blended with cement to form an inorganic plate. Hereinafter, the present invention will be described in detail.

The pulp used in the present invention is wood pulp, linter pulp, hemp pulp, etc., and may be either bleached or unbleached. This is beaten in treated water containing inorganic ions. The treated water used in the present invention is a high-concentration inorganic ionized water containing calcium (Ca) as a main component, silicon (Si), aluminum (Al), iron (Fe), and magnesium (M).
g) and the like.

By beating the pulp in the treated water containing inorganic ions as described above, the non-combustible filler, which is an inorganic ion, can be deposited and adhered to the surface of the pulp, and the calorific value of the pulp can be reduced by the non-combustible filler. Can be suppressed. Also, by beating the pulp, the surface area of the pulp can be increased, the amount of non-combustible filler adhering to the surface of the pulp can be increased, and the decrease in the calorific value of the pulp can be promoted. And, since the pulp treated in the present invention has a small calorific value, even if it is added to the inorganic plate more than usual, the fire prevention performance of the inorganic plate is not reduced, and therefore, the inorganic plate is treated in the present invention. The pulp can be blended in a large amount to secure the mechanical strength of the inorganic plate.

The above-mentioned treated water is a waste liquid (called white water) generated in the process of forming an inorganic plate mainly composed of cement by a papermaking method, for example, a supernatant liquid of cement slurry (cement water) or a cement slurry. such as Ru with water generated in the dehydration process. When using this waste as treated water had a solid content concentration of Ru 0.5～4.0Wt% der. If the solid content is less than 0.5% by weight, inorganic ions cannot be sufficiently adhered to the pulp, and the solid content concentration is 4.
If it exceeds 0 wt%, the inorganic ions may precipitate as crystals or the like, which may adversely affect the beating equipment used for carrying out the present invention. By using the waste liquid generated during the papermaking process of the cement slurry as the treated water , the waste liquid that is normally discarded can be effectively used.

In the present invention, a disc refiner or a beater can be used as a beating facility for beating pulp. The beating degree of the pulp is preferably not less than 60 csf and not more than 500 csf in Canadian standard freeness. If the beating degree is less than 60 csf, the fibers of the pulp may be finely cut, thereby impairing the effect of reinforcing the cement. And the surface area of the pulp becomes small, and the inorganic ions may not be sufficiently adhered to the surface of the fibers of the pulp.

An inorganic plate can be formed by blending the treated pulp treated by the present invention, ordinary untreated pulp not treated as described above, cement, filler and aggregate. In this inorganic plate, the total pulp content of the treated pulp and the untreated pulp is preferably 3 to 8% by weight based on the total solid content of the inorganic plate. If the total pulp content is less than 3 wt%, the inorganic plate cannot be sufficiently reinforced, and if the total pulp content exceeds 8 wt%, the cement may be too small to form the inorganic plate. Of the total pulp volume, treated pulp accounts for 4
0 wt% or more can be blended. 40 treated pulp
If the amount is less than wt%, the mixing ratio of the amount of the untreated pulp increases, and the calorific value of the inorganic plate may not be sufficiently reduced.

As the cement, any of plain cement such as ordinary Portland cement, early-strength Portland cement and medium-grade Portland cement, and special cement such as mixed Portland cement, alumina cement and magnesia cement can be used. It is preferred to use Portland cement. Silica or silica powder can be used as the filler or aggregate.

The above-mentioned inorganic plate can be formed by any molding method. A slurry is prepared by adding water to the above-mentioned materials such as cement and pulp, and the slurry is formed into a net to form a sheet. Thereafter, the sheet is preferably formed by a so-called sheet forming method in which the sheet is dehydrated and cured. The supernatant liquid of the slurry and the water generated when the papermaking sheet is dewatered are used as the treated water for the pulp treatment.

[0015] Since the inorganic plate thus formed uses pulp having a small calorific value, blending this pulp in a larger amount than usual does not lower the fire prevention performance of the inorganic plate. A large amount of beaten pulp is blended in treated water containing water to secure mechanical strength while maintaining high fire resistance, and to increase both fire resistance and mechanical strength.

[0016]

The present invention will be described below in detail with reference to examples. (Example) As pulp, NU manufactured by Hyogo Pulp Industry Co., Ltd. was used.
KP (softwood unbleached sulfate pulp) was used. This pulp is blended with treated water using the supernatant of ordinary Portland cement (solid content: 1.8 wt%), and the pulp is beaten to 200 cs with a disk refiner manufactured by Ishikawajima Kikai Co., Ltd.
f, and a beaten pulp slurry having a pulp concentration of 5 wt% was prepared.

Next, 53 parts by weight of ordinary Portland cement (OPC) and 2 parts of silica sand No. 8 were added to the beaten pulp slurry.
0 parts by weight, 20 parts by weight of silica powder, and 3 parts by weight of the same unbeaten pulp as above, and the slurry concentration was 10 parts by weight.
A wt% cement slurry was prepared. In addition, 4 parts by weight of the treated pulp was blended. Next, this cement slurry was formed into a paper by a 4-bat, 3-ply round net paper machine, and dewatered by using a filter press at a pressure of 100 kg / cm ² and a holding time of 1 second to form a sheet.

Next, the sheet was cured by humid heat curing for 7 days, and then the surface was coated with acrylic to form an inorganic plate. (Comparative Example 1) Treated pulp was prepared by using pure water containing no inorganic ions as treated water and beaten the pulp in the treated water. Except for this, an inorganic plate was formed in the same manner as in the above example.

(Comparative Example 2) Inorganic ionized water was used as treated water, and only pulp was disintegrated in the treated water to obtain treated pulp having a beating degree of 650 csf. Except for this, an inorganic plate was formed in the same manner as in the above example. As a result of performing a base material test using the inorganic plates of the above-described example and comparative examples 1 and 2, the example obtained passed a base material test with a temperature rise of 38 ° C. as indicated by a solid line in FIG. However, in the case of Comparative Examples 1 and 2, as shown by the dotted line in FIG.
At 52 ° C., the furnace temperature exceeded 800 ° C. (two-dot chain line in FIG. 1), and the base material test was rejected. In other words, the example has high fire prevention performance even when the same amount of pulp as those of comparative examples 1 and 2 is used. The figure
In No. 1 , since the heat generation characteristic curves of Comparative Example 1 and Comparative Example 2 have no significant difference, both are indicated by the same dotted line.

[0020]

As described above, according to the present invention, since the pulp is beaten in the treated water containing the inorganic ions, the non-combustible filler, which is an inorganic ion, can be deposited and adhered to the surface of the pulp. The calorific value of the pulp can be suppressed by the filler, and the calorific value of the inorganic plate in the base material test can be reduced.

The solid content concentration is 0.5 to 4.0 wt%
In the wastewater generated in the process of papermaking of the cement-containing slurry was used as the treated water, so that inorganic ions can be sufficiently adhered to the pulp and excess inorganic ions can be precipitated as crystals and the like. In addition, there is no possibility of adversely affecting the beating equipment used to carry out the present invention. Further, by using the waste liquid generated in the process of making the cement slurry as the treated water , the waste liquid which is normally discarded can be effectively used.

Further, since the beating degree of the pulp is set to be not less than 60 csf and not more than 500 csf in Canadian standard freeness, there is no danger that the fibers of the pulp are cut finely and the effect of reinforcing the cement is impaired, and the pulp fibers are not finely divided. It is sufficient that it is not easily dispersed in the cement slurry, and that the surface area of the pulp is not reduced so that inorganic ions cannot be sufficiently attached to the surface of the fiber of the pulp.

[Brief description of the drawings]

FIG. 1 is a graph showing a heat generation characteristic curve in a base material test of inorganic plates of Examples of the present invention and Comparative Examples 1 and 2.

FIG. 2 is a graph showing a heat generation characteristic curve in a substrate test.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) D21C 1/00-11/14 D21D 1/00-5/28

Claims (2)

(57) [Claims] (1) The treated water containing an inorganic ion is a solid content
Concentration of 0.5-4.0 wt%, cement containing
Using wastewater generated during the rally papermaking process, this treated water
A method for treating pulp, comprising beating pulp inside . 2. The pulp has a beating degree of 6 standard Canadian freeness.
The pulp treatment method according to claim 1, wherein the pulp is set to 0 csf or more and 500 csf or less .