JPH11255542A - Hydraulic cement composition and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-fluidity ecological cement and its production process. SOLUTION: This cement composition is a baked material produced by using one or more kinds of incinerated municipal waste ash and incinerated sewage sludge ash as a raw material, composed of a hydraulic composition comprising a composition containing calcium silicate and 10-40 wt.% of one or more components selected from calcium chloroaluminate, calcium fluoroaluminate and calcium aluminate and optionally gypsum and containing water in the composition in the form of hydrated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a hydraulic composition (hereinafter referred to as a "hydraulic composition") comprising a calcined product produced from waste such as municipal garbage incineration ash and sewage sludge incineration ash and gypsum added as needed. More specifically, the present invention relates to a hydraulic cement composition based on eco-cement, and more particularly, to a high-fluidity quick-setting hydraulic cement composition based on eco-cement (hereinafter, referred to as high-flow eco-cement), and And a method for producing the same.

[0002]

2. Description of the Related Art In recent years, general waste such as municipal waste and sewage sludge and industrial waste have increased remarkably, and effective use and recycling of waste have been attempted in various fields. There is no traditional method, and at present, it depends on landfill. However, recently, in the field of cement production, eco-cement has been produced from waste such as municipal waste incineration ash and sewage sludge incineration ash for the purpose of effective use and recycling of waste.

[0003] However, ecocement is a fast-setting mineral derived from its raw material components, ie, calcium aluminate (eg, C ₃ A), calcium fluoroaluminate (eg, C ₁₁ A ₇ CaF ₂ ), calcium chloroaluminum. sulfonates (e.g., C ₁₁ a ₇ CaCl ₂₎ and contains any one or more, when the content of minerals such rapid hardening increases, or the fluidity thereof significantly decreases due to the high hydration reactivity Inconveniences such as insufficient pot life cannot be obtained. Although quick-setting itself is an advantage in some applications, even in such cases, large amounts of organic admixtures such as water-reducing agents and retarders must be added in order to ensure the fluidity and pot life required for the casting operation. Becomes indispensable. In addition, if such cement is mixed with other cement and used, the problem of pot life can be reduced and the advantage of quick setting can be obtained.
The problem of reduced liquidity remains unsolved.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems in ecocement, and makes use of the quick-setting property of ecocement while remarkably reducing fluidity and shorting pot life. A hydraulic cement composition (high-flow eco-cement) and a method for producing the same, which solve the problem, improve the quality of eco-cement contributing to effective use and recycling of waste, and enable expansion of its use To provide.

[0005]

That is, the present invention provides:
(1) A fired product made from at least one of municipal waste incineration ash and sewage sludge incineration ash, wherein 10 to 40% by weight of at least one of calcium chloroaluminate, calcium fluoroaluminate and calcium aluminate and calcium silicate The present invention relates to a hydraulic cement composition formed of a hydraulic composition comprising a calcined product containing and gypsum optionally added, wherein water is held in a hydrated form. The hydraulic cement composition of the present invention is, for example, (2) water retained by a hydrate coating layer formed on the particle surface of the hydraulic composition.

The present invention also relates to (3) a hydraulic cement composition formed from the hydraulic composition of (1) and containing a water-absorbing polymer. The hydraulic cement composition of the present invention includes (4) a composition in which water is retained in the form of a hydrate and contains a water-absorbing polymer.

[0007] The hydraulic cement composition of the present invention comprises:
(5) those having a water content (water / hydraulic cement composition) of 0.2 to 5% by weight in the hydraulic cement composition; (6)
It includes a material obtained by mixing a hydraulic material with any of the above hydraulic cement compositions (1) to (5).

Further, the present invention provides (7) water and, if necessary, water-absorbing time from the pulverizing step in the production of the hydraulic composition of (1) to the addition of mixing water when using cement. The present invention relates to a method for producing a hydraulic cement composition, which comprises adding and mixing a polymer. (8) A hydraulic cement characterized by adding and mixing the hydraulic cement composition of any of the above (1) to (5) at an appropriate time after the production of the cement and before the addition of mixing water. The present invention relates to a method for producing the composition.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below. (I) High flow ecocement Hydraulic cement composition of the present invention (high flow ecocement)
Is a fired product made from at least one of municipal garbage incineration ash and sewage sludge incineration ash, wherein 10 to 40% by weight of calcium chloroaluminate, calcium fluoroaluminate, and calcium aluminate is used, and calcium silicate is used. The main component is an eco-cement formed of a calcined product containing the composition and a hydraulic composition composed of gypsum added as necessary.

In the above mineral composition, for example, calcium chloroaluminate is 11CaO.7Al ₂ O ₃ .C
aCl ₂ (abbreviated as C ₁₁ A ₇ CaCl ₂ ), and calcium fluoroaluminate is 11Ca
_{O · 7Al 2 O 3 · CaF} 2 (C 11 A 7 CaF 2 hereinafter) is represented by the composition formula. The calcium aluminate is, for example, 3CaO.Al ₂ O ₃ (abbreviated as C ₃ A). In addition, dicalcium silicate (2CaO.SiO ₂ , hereinafter abbreviated as C ₂ S) and tricalcium silicate (3CaO.SiO ₂ , hereinafter C ₃ ) contained in ordinary cement are used.
S).

Raw materials for ecocement include sewage sludge dry powder obtained by mixing quicklime with shells and sewage sludge, and other general wastes and industrial wastes. Further, limestone, clay, quartzite, which are ordinary cement raw materials, are used. , Aluminum ash, bauxite, iron, or the like may be used as a raw material and the components thereof are adjusted.
Clinker obtained by calcining these raw materials at 1200 to 1500 ° C. is pulverized, and if necessary, gypsum is added at the time of pulverization or after pulverization to produce ecocement.

The aluminum source in the fired product is mainly derived from incinerated ash. Therefore, C ₁₁ A ₇ CaCl ₂ , C ₁₁ A ₇
The content of aluminum compounds such as CaF ₂ and C ₃ A is 10
When the content is less than the weight%, the amount of incinerated ash is reduced, which is not preferable from the viewpoint of effective use of waste and recycling. On the other hand, if the amount exceeds 40% by weight, the hardened cement body may be excessively expanded due to the progress of hydration, which is not appropriate.

The gypsum added to the calcined product may be any of anhydrous gypsum, gypsum dihydrate and gypsum hemihydrate. From the strength development, the amount of gypsum added is 1 to 100 parts by weight of the calcined material.
30 parts by weight are preferred.

The high flow ecocement of the present invention is obtained by retaining water in non-free water form, that is, hydrate form. Preferably, this water is retained in the form of a hydrated coating layer covering the particle surface. If the added water is in the form of free water, it is not preferable because it generates solids and deteriorates the quality during storage.However, the water fixed in the form of hydrate does not cause such inconvenience, but rather kneads. Occasionally, the hydrate coating layer covering the particle surface suppresses the rapid hydration reaction of ecocement to maintain fluidity. As a result, the consumption of the water reducing agent, the retarding agent, and the like can be reduced, and the effect can be maintained.

[0015] In the high fluidity eco-cement (hydraulic cement composition) of the present invention, a preferable water content is 0.2 to 5% by weight (water / hydraulic cement composition) as a ratio to the hydraulic cement composition. Suitable, 0.5-4% by weight
Is preferable, and 1 to 3% by weight is more preferable. If it is less than 0.2% by weight, a sufficient fluidity improving effect cannot be obtained.
If the content exceeds 10% by weight, it causes the formation of solidified substances.

In order to keep the water in the form of a hydrate in the ecocement particles, water may be added in the pulverizing step in the production of ecocement, or water may be added to the pulverized ecocement powder and mixed. Is also good. Further, an appropriate amount of water may be added to and mixed with the ecocement powder before adding the mixing water at the time of use. When water is added in the pulverization step during cement production, water may be sprinkled into the mill together with a pulverization aid or the like, or may be added to the powder input to the classifier or the powder returned from the classifier to the mill. . When water is added to the pulverized eco-cement powder, various types of powder mixing devices such as a Henschel mixer (vertical stirring type high-speed fluidizing mixer) and an air blender can be used. When water is added immediately before use, various mixers used for mixing concrete can be used, such as a pan mixer and a twin-screw forced stirring mixer.

As described above, by adding an appropriate amount of water to the ecocement powder and mixing, the ettringite (C
_{3 A · 3CaSO 4 · 32H 2} O), mono-monkey Fe maleate hydrate _{(C 3 A · CaSO 4 ·} 12H 2 O), hydrates such as calcium silicate hydrate (C-S-H) generated And adheres to the surface of the cement particles, and as this proceeds, forms a coating layer covering the surface of the particles. Even if the entire surface of the cement particle is not covered with the hydrate, if a certain amount of hydrate adheres to the surface of the cement particle, the rapid hydration reaction can be suppressed. In the present invention, that the water is held in the form of a hydrate means not only that the entire surface of the cement particles is covered with the hydrate, but also includes such a state.

[0018] The hydraulic cement composition of the present invention may contain a water-absorbing polymer, if necessary. The water-absorbing polymer used in the present invention preferably has a water-absorbing ability at least 5 times its own weight. As the type of the water-absorbing polymer, for example, acrylic acid type, starch / acrylic acid type, maleic acid type, cellulose type, polyvinyl alcohol type and the like can be used. The water-absorbing polymer in the hydraulic cement composition of the present invention has an effect of removing excess free water by its water absorption and preventing the generation of solidified substances and the quality deterioration during storage. Also, after kneading, a part of the kneading water is absorbed and then gradually released, thereby maintaining high fluidity.

The water-absorbing polymer may be added to and mixed with Ecocement in advance, or an appropriate amount may be added and mixed before kneading at the time of use. The water and the water-absorbing polymer that enhance the fluidity may be added separately, but if the water is absorbed in the water-absorbing polymer in advance and added as a kind of solid, the added water becomes difficult to volatilize. It is preferable because it can be efficiently held on the particle surface.

The amount of the water-absorbing polymer to be added is suitably not more than 0.2 parts by weight per 100 parts by weight of Ecocement.
0.005 to 0.2 part by weight is preferable, and 0.01 to 0.1 part by weight is more preferable. Since the water-absorbing polymer is a polymer, it has an effect similar to that of a thickener, and an excessive addition thereof is not preferable because it causes inconvenience such as a decrease in fluidity.

As described above, the hydraulic cement composition of the present invention based on ecocement (high flow ecocement)
Can be obtained by adding and mixing water and a water-absorbing polymer as needed at a suitable time from the pulverizing step in the production of ecocement to before the addition of mixing water at the time of on-site use.

(II) Hydraulic Properties Mixed with High Fluid Ecocement
Cement composition The hydraulic cement composition of the present invention can also be obtained by mixing the above-mentioned high-flow ecocement with various hydraulic materials such as ordinary cement. The hydraulic cement composition of the present invention also includes such a mixed cement. The hydraulic material may be any inorganic material exhibiting hydraulic properties. For example, various types of Portland cement such as ordinary, fast, super fast, moderate heat, and high belite, and blast furnace slag and fly Various mixed cements in which ash, siliceous admixture, silica fume and the like are mixed can be used. By mixing a high-flow eco-cement with these hydraulic materials, it is possible to obtain a hydraulic cement composition exhibiting quick-setting while maintaining sufficient fluidity.

The mixing ratio of the hydraulic material and the high fluidity ecocement is not particularly limited, and the required fluidity and setting time can be freely controlled by changing the mixing ratio according to the application.

The mixing of the hydraulic material and the high-flow eco-cement can be carried out in a timely manner after the production of the high-flow eco-cement and before the addition of the mixing water at the time of use on site. For example, in the case of manufacturing a highly fluidized eco-cement by adding a predetermined amount of water at the time of clinker grinding in the process of producing an eco-cement, the hydraulic material and the highly fluidized eco-cement are put into a powder mixer following the grinding process. Then, they can be mixed to produce the hydraulic cement material of the present invention. Further, at the time of use on site, the two materials may be mixed using a mixer or the like immediately before the mixing water is added. These powder mixers and mixers may continue to use the same mixer to continue the mixing and stirring operation, or may be replaced with another one.

The hydraulic cement composition comprising the high-flow eco-cement of the present invention, or the hydraulic cement composition obtained by mixing the high-flow eco-cement with a hydraulic material, may be mixed with a water reducing agent or Various organic admixtures such as retarders can be used. The type of the organic admixture is not limited, and for example, a general cement / concrete can be appropriately used.

[0026]

The hydraulic cement composition of the present invention (high-flow eco-cement and a hydraulic composition obtained by mixing the same) can reduce the use of various organic admixtures as compared with conventional eco-cement. Sufficient fluidity and pot life can be obtained with a smaller amount of use than in the case of Ecocement. In addition, since the amount of various organic admixtures can be reduced, adverse effects on hydration due to excessive addition of the admixtures can be avoided, and good strength can be obtained over a long period of time. In addition, a mixture of ordinary Portland cement or the like and a highly fluidized eco-cement having a modified surface can have quick-setting properties while maintaining fluidity. Therefore,
These hydraulic cement compositions of the present invention can be widely used in various applications such as civil engineering and construction.

[0027]

Examples of the present invention will be described below. These are examples and do not limit the present invention. The ecocement used in this example was manufactured as follows. Manufacturing method of ecocement 54.3% by weight of dried municipal waste incineration ash, 42.5% by weight of limestone powder, 1.1% by weight of aluminum ash, clay 1.
Clinker was fired at 1300 to 1450 ° C. using a rotary kiln by using 1% by weight and 0.5% by weight of fluorite as raw materials. The obtained clinker was pulverized by a rigid mill so that the Blaine specific surface area became 4000 cm ² / g.
12 parts by weight of anhydrous gypsum was added to 00 parts by weight to produce an ecocement having a Blaine specific surface area of 4700 cm ² / g. Table 2 shows the mineral composition of the manufactured fired product.

[0028]

[Table 1]

[0029]

[Table 2]

Example 1 (Surface Modified Ecocement Only) A mixture of 0.04% by weight of a water-absorbing polymer and 0.1 to 10% by weight of water with respect to the above-mentioned ecocement was mixed with the ecocement to form a powder. The mixture was placed in a body mixer (Henschel mixer) and mixed and stirred to obtain a surface-modified eco-cement. Using this surface-modified eco-cement, water / cement ratio = 0.5
The mortar was prepared by mixing at a mixing ratio of 0, the sand / cement ratio = 3.0, and the amount of admixture used = 0.8% by weight of the cement weight. Standard sand of Japanese Industrial Standards (JIS R 5201-1997) was used as the sand. The admixture used was a product of Chichibu Onoda Company (trade name: Coreflow NP55). Unmodified ecocement was used for the comparative sample (No. 1). The mortar flow immediately after kneading and 60 minutes after mixing of the mortar was measured according to Japanese Industrial Standards (JIS R52).
Using the flow cone of 01), the stationary flow was measured on a glass plate. The results are shown in Table 3. Here, a sample having a water content of 0.2 to 5% by weight (No. 3 to No. 5) is a comparative sample (No. 1).
The flow value was much larger than that of the above, and a remarkable fluidity improvement effect was observed. On the other hand, a sample having a moisture content of 0.01% by weight (No.
2) has a small increase in flow value and a water content of 10% by weight.
In sample No. 6 (No. 6), a large amount of condensate was generated during surface modification of ecocement, making it unsuitable as cement.

[0031]

[Table 3]

Example 2 (Mixing of surface-modified eco-cement and ordinary cement) Table 4 shows the surface-modified eco-cement and ordinary Portland cement using a surface-modified eco-cement having a water content of 2.0% by weight. A mixed cement was prepared by mixing at a mixing ratio of water / cement ratio = 0.45, sand / cement ratio = 3.0, admixture used = 0.8% by weight of cement weight. To prepare a mortar. Sand is based on Japanese Industrial Standards (JI
Standard sand of SR 5201-1997) was used. The admixture used was a product of Chichibu Onodasha (trade name: Coreflow NP55), and the ordinary Portland cement used was a product of Chichibu Onodasha. Comparative sample No. 2-1 is an example of ordinary Portland cement alone, and comparative samples No. 2-7 and No. 2-8 are samples to which ecocement which does not modify the surface is added. The mortar flow immediately after kneading of the mortar was measured using a flow cone of Japanese Industrial Standard (JIS R 5201) on a glass plate. The water / cement ratio of each cement sample was determined according to JIS R 5201.
The setting time was measured at 0.30. Table 4 shows the results.

As shown in the results of Table 4, the mixture of the surface-modified eco-cement has a high flow value in proportion to the amount of the mixture, has excellent fluidity, and has a setting time of It is short and fast-curing. On the other hand, the one using the unmodified surface eco-cement (comparative sample) has low fluidity and the setting time is too short.

[0034]

[Table 4]

Claims (8)

[Claims] 1. A fired product obtained from at least one of municipal waste incineration ash and sewage sludge incineration ash, wherein at least one of calcium chloroaluminate, calcium fluoroaluminate, and calcium aluminate is contained in an amount of 10 to 40% by weight. A hydraulic cement composition formed by a hydraulic composition comprising a calcined product containing calcium silicate and gypsum optionally added, wherein water is held in a hydrated form. 2. The hydraulic cement composition according to claim 1, wherein water is retained by a hydrate coating layer formed on the surface of the particles of the hydraulic composition. 3. A hydraulic cement composition formed by the hydraulic composition of claim 1 and containing a water-absorbing polymer. 4. A hydraulic cement composition according to claim 1, wherein the water is retained in the form of a hydrate and contains a water-absorbing polymer. 5. The amount of water (water / water) in a hydraulic cement composition.
The hydraulic cement composition according to any one of claims 1 to 4, wherein the hydraulic cement composition is 0.2 to 5% by weight. 6. A hydraulic cement composition obtained by mixing the hydraulic cement composition according to claim 1 with a hydraulic material. 7. Addition and mixing of water and a water-absorbing polymer as necessary at a time from the pulverizing step in the production of the hydraulic composition according to claim 1 to before the addition of mixing water when using cement. A method for producing a hydraulic cement composition, comprising: 8. A hydraulic cement composition characterized in that the hydraulic cement composition according to any one of claims 1 to 5 is added and mixed at an appropriate time after the production of the cement and before the addition of mixing water. Production method.