JP2613807B2 - Manufacturing method of lightweight inorganic extruded product - Google Patents

Description

The present invention relates to a method for producing a lightweight inorganic extruded product,
More specifically, the present invention relates to a method of extruding a kneaded material obtained by kneading a raw material composition comprising a hydraulic inorganic raw material as a main raw material, a thickener, a lightweight aggregate, and water, and forming a molded product.

<Prior art and its problems> A raw material composition comprising a hydraulic inorganic material represented by cement as a main component, a fibrous material, a thickener, an aggregate and water added thereto is kneaded. There has been known a method for extruding a molded product by an extruder and subjecting the obtained molded product to natural curing or autoclave curing in a curing room to produce a molded product.

However, since the extruded product obtained by the above-described conventional technique is extruded at a high pressure using an extruder, only an extruded product having a high specific gravity can be obtained.

Therefore, in order to obtain an extruded product having a low specific gravity, attempts have been made to mix light-weight aggregates such as pearlite, expanded synthetic resin particles and papermaking sludge incineration ash with the basic components of the above-mentioned raw material composition. However, since pearlite itself has low compressive strength, it collapses due to the pressure during extrusion molding, and it has been practically difficult to reduce the weight. In addition, foamed synthetic resin particles are effective in achieving weight reduction, but those that shrink due to the pressure during extrusion molding are extruded from the molding machine and generate an expansion force that attempts to restore the original shape. The expansion force causes expansion of the entire formed plate, which hinders dimensional stability of the formed plate. Further, the foamed synthetic resin particles have a problem that the strength is reduced in proportion to the weight reduction because the adhesive strength with the cement is weak.

Paper sludge incineration ash has high compressive strength, is lightweight and inexpensive, and furthermore, since incineration ash has latent hydraulic properties, it has recently come to be used by being mixed into a raw material composition for extrusion molding. I have. However, since paper sludge incineration ash, which is generally available, is obtained by incinerating paper sludge for the main purpose of landfill, etc., 6 to 15% of organic residues are contained in paper sludge incineration ash. This organic residue is present in a state of being adhered to crystals constituting paper sludge incineration ash. Therefore, when used as an extruded lightweight aggregate, the flowability of the kneaded material decreases with the amount of addition, and when a sufficient amount of papermaking sludge incineration ash is added to achieve weight reduction, the extruded material is extruded. There was a problem that molding became impossible. In order to solve this problem, it is necessary to greatly increase the amount of expensive thickener such as methylcellulose and water to be added, resulting in an increase in production cost.

<Means for Solving the Problems> As a result of further study on the above-mentioned problem in the case of extruding by adding papermaking sludge incineration ash to the raw material composition, the present inventor found that the organic residue adhering to the papermaking sludge incineration ash was obtained. It was concluded that the components acted as activated carbon to adsorb the thickener and water, thereby reducing the extruded fluidity of the kneaded product.
The present inventors have found that the above problem can be solved by using paper sludge ash fired until the organic residue becomes 5% or less as a lightweight aggregate, and have completed the present invention.

That is, the present invention relates to a method for producing a molded article by extruding a kneaded material obtained by kneading a raw material composition containing a hydraulic inorganic material as a main raw material, in the raw material composition, as a lightweight aggregate. A method for producing a lightweight inorganic extruded product, comprising adding papermaking sludge baked ash whose organic residue has been baked to 5% or less.

The papermaking sludge calcined ash used in the present invention is obtained by calcining papermaking sludge discharged from paper, a pulse mill or the like, and has an organic residue of 5% or less, preferably 1% or less, more preferably 0.5% or less. % Is used. The organic residue is an organic carbon mainly composed of a residual carbon compound still remaining in the calcined ash obtained by calcining the papermaking sludge, and the mass of the mass when the papermaking sludge calcined ash is burned as a sample. It is displayed as a decrease, that is, a burning loss.

This organic residue is present in a state of adhesion between the crystal surface and the crystals of the paper sludge incineration ash formed in a state where the plate-like crystals are aggregated, and is added for the purpose of improving the fluidity of the kneaded material. It has the property of adsorbing a thickener such as methylcellulose and the like and moisture, and consequently lowers the fluidity of the kneaded material. Generally, as much as 6 to 15% of organic residues remain in the incineration ash of paper sludge that is incinerated mainly for landfilling in order to effectively use paper sludge. The papermaking sludge calcined ash used in the present invention burns such papermaking sludge incinerated ash over a longer period of time to burn off organic carbon mainly composed of residual carbon compounds and to increase voids between plate-like crystals. And the organic residue is 5%
The content is preferably reduced to 1% or less, more preferably 0.5% or less. Further, the papermaking sludge itself can be fired over a long period of time to reduce the organic residue to 5% or less, thereby obtaining papermaking sludge fired ash used in the present invention.

By using the papermaking sludge ash with reduced organic residue as a lightweight aggregate, the thickener and water in the kneaded material can be obtained even if the added amount is increased and the weight of the molded article is reduced. It is not necessary to increase the amount of addition. Even if the papermaking sludge calcined ash is increased to about 120% by weight based on the amount of the hydraulic raw inorganic material, good extrusion molding can be performed without lowering the fluidity of the kneaded material.

The particle size of the papermaking sludge calcined ash used in the present invention is appropriately selected in relation to the dispersibility in the kneaded material and the like.
It is desirable that the mesh pass is about 250 meshes remaining. The bulk specific gravity of the papermaking sludge calcined ash is preferably in the range of 0.3 to 0.6, more preferably 0.3 to 0.5.

The raw material composition in the present invention is mainly composed of Portland cement, alumina cement, blast furnace slag cement, mixed cement, gypsum, slag, etc. as a hydraulic inorganic material, and in addition to the papermaking sludge calcined ash, Vinylon (registered trademark), Fibrous materials such as polypropylene, acrylic, glass, aramid, carbon, metal, rock wool, pulp, edenite, walathnite, sepiolite, thickeners such as methyl cellulose, ethyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, polyethylene oxide, polyvinyl alcohol, and fly Reactive aggregates such as ash, silica fume, silica sand, diatomaceous earth, and lime, and, if necessary, aggregates such as calcium carbonate, clay, and sand, and water. These raw materials can be used alone or in combination of two or more. In general, those obtained by mixing and kneading according to a basic composition at the time of extrusion-forming an inorganic plate can be used.

In particular, when Portland cement and slag are used as a mixture as a hydraulic inorganic material, and when blast furnace slag cement is used, sufficient strength is obtained by normal pressure curing such as natural curing or steam curing, and the generation of Efro occurs. It is preferable because it is small. Further, the addition of slag suppresses the generation of initial strength, and a long-term strength can be obtained by a hydration reaction of slag after curing, so that it is suitable for extrusion molding. Furthermore, there is an advantage that the weight can be reduced, the formed plate material after the effect is excellent in flexibility, the cutting workability is good, and cracks do not occur even in the nail.

Table 1 shows typical blending examples when slag cement is used as the hydraulic inorganic material.

In order to manufacture an inorganic plate according to the present invention, a mixture of a fibrous material, a thickener, an aggregate and the like and a papermaking sludge ash having an organic residue of 5% or less are further mixed with a hydraulic inorganic material as a main raw material. The obtained raw material composition is kneaded with a mixer, and then an appropriate amount of water is added to obtain a kneaded material. The kneaded material is extruded by an extruder to obtain a continuous molded plate. The obtained molded plate is cut into an appropriate length, molded by press molding or the like, and cured by natural curing or steam curing at 40 to 90 °, whereby a lightweight inorganic extruded molded plate can be manufactured.

<Action> Papermaking sludge ash having an organic residue of 5% or less is added as a lightweight aggregate to the extruded material, and the adsorbing action of the thickener and water by the organic residue is suppressed while the extruded material is used as a lightweight aggregate. Lightening can be achieved.

<Examples> 63 parts by weight of slag cement (a mixture of 60% by weight of slag and 40% by weight of Portland cement), 3 parts by weight of pulp, 1.0 part by weight of methylcellulose, 1.0 part by weight of Vinylon (registered trademark) and the composition shown in Table 2 A mixture of 31.5 parts by weight of papermaking sludge ash having an organic residue of 0.13% was kneaded with a xixer and further kneaded with 54 parts by weight of water. The obtained kneaded material is extruded by an extruder, and has a thickness of 12 mm and a width of 470 mm.
Was obtained. The obtained continuous molded plate was cut into an appropriate length, and was steam-cured at 40 to 90 ° C. for 20 hours to obtain an inorganic plate. The specific gravity of the obtained inorganic plate is 1.05 g /
It was cm ^2.

Comparative Example The organic residue of the papermaking sludge calcined ash used in the above example was
Extrusion was attempted in the same manner as in the above example except that 5.4% was used, but extrusion by an extruder could not be performed.

<Effects of the Invention> According to the present invention, in a method for producing a lightweight inorganic molded product by an extrusion molding method, by using papermaking sludge ash obtained by firing papermaking sludge to an organic residue of 5% or less as a lightweight aggregate, Extrusion by an extruder can be performed without increasing the amounts of the thickener and water added, and an industrially inexpensive lightweight inorganic plate can be manufactured.

Claims (2)

(57) [Claims] 1. A method for producing a molded product by extruding and kneading a kneaded material obtained by kneading a raw material composition containing a hydraulic inorganic material as a main raw material, wherein the raw material composition is used as a lightweight aggregate. A method for producing a lightweight inorganic extruded product, comprising adding papermaking sludge calcined ash calcined to an organic residue of 5% or less. 2. The method for producing a lightweight inorganic extruded product according to claim 1, wherein the calcined ash of the papermaking sludge has an organic residue of 1% or less.