JPH11228209A - Hydraulic cement composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a hydraulic cement composition having excellent fluidity, comprising an ecocement. SOLUTION: In a baked material comprising one or more of an incinerated ash of municipal refuse and a burned ash of sewage sludge, a hydraulic composition composed of the baked material containing 10-40 wt.% of one or more of calcium chloroaluminate, calcium fluoroaluminate and calcium aluminate and calcium silicate and a gypsum is mixed with limestone powder to give the objective hydraulic cement composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic composition obtained by mixing limestone powder with a hydraulic composition (hereinafter referred to as "ecocement") produced from waste such as incineration ash of municipal waste and incineration ash of sewage sludge. The present invention relates to a cement composition, and more particularly to a hydraulic cement composition having improved flowability of ecocement.

[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. However, ecocement is a fired product using municipal waste incineration ash, sewage sludge incineration ash, or the like as a raw material, and C ₁₁ A ₇ CaCl ₂ and C ₁₁ A ₇ derived from the raw material are used.
High content of aluminum compounds such as CaF ₂ and C ₃ A,
Since these have remarkable initial hydration activity, there is a problem that the setting time is short and it is difficult to obtain a suitable fluidity.

Generally, in order to improve fluidity, agents such as a high-performance water reducing agent and a high-performance AE water reducing agent that promote dispersion of powder are used. However, in the case of ecocement containing a large amount of aluminum compound having initial hydration activity, which is a noticeable chopstick, in order to obtain suitable fluidity using these chemicals, a large amount has to be added. Properties may be impaired. Further, depending on the drug, the effect of improving the fluidity may not be obtained.

As described above, a high performance water reducing agent or a high performance A
It is pointed out that it is not possible to sufficiently improve the flowability of Ecocement by using a method such as E water reducer to increase the flowability, which may hinder the effective use of Ecocement and expansion of applications. Is done. Ecocement meets the demands of effective use and recycling of waste, and there is a need for improved liquidity in order to promote its widespread use.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the drawback of ecocement in that it is difficult to obtain suitable fluidity, and effectively uses and recycles waste by expanding the use of ecocement manufactured from waste. An object of the present invention is to provide a hydraulic cement composition capable of achieving the following.

[0006]

Means for Solving the Problems The present inventors have improved the fluidity of limestone powder by mixing it with ecocement. That is, the present invention relates to (1) a calcined product using at least one of municipal garbage incineration ash and sewage sludge incineration ash as a raw material. The present invention relates to a hydraulic cement composition obtained by mixing limestone powder with a hydraulic composition composed of a calcined product containing 40% by weight and calcium silicate and gypsum. In the hydraulic cement composition of the present invention, preferably, (2) the mixed limestone powder has an inner percentage of 5 to 40% by weight, and (3) the limestone powder has a Blaine specific surface area of 3,000 cm ² / g or more. , Containing 10% by weight or more of fine particles of 1 μm or less.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to examples and comparative examples. The hydraulic cement composition of the present invention is a calcined product made from at least one of municipal waste incineration ash and sewage sludge incineration ash, and comprises at least one of calcium chloroaluminate, calcium fluoroaluminate and calcium aluminate. It is mainly made of eco-cement obtained by a hydraulic composition composed of a calcined product containing gypsum and 焼 成 40% by weight and calcium silicate.

In the above mineral composition, calcium chloroaluminate is composed of 11CaO.7Al ₂ O ₃ .CaCl ₂
(Abbreviated as C ₁₁ A ₇ CaCl ₂ ), and calcium fluoroaluminate is 11CaO · 7
Al ₂ O ₃ .CaF ₂ (abbreviated as C ₁₁ A ₇ CaF ₂ ) is included. Calcium aluminate is 3Ca
O.Al ₂ O ₃ (abbreviated as C ₃ A). In addition, dicalcium silicate (C ₂
S) and tricalcium silicate (C ₃ S)
Including more than species.

The raw materials of ecocement include sewage sludge dry powder obtained by mixing quicklime with shells and sewage sludge, other general wastes and industrial wastes, and limestone, clay, silica stone, aluminum ash, and bauxite, which are common cement raw materials. It may be a raw material whose components are adjusted by mixing with iron, iron and the like. 12 such raw materials
After crushing the clinker obtained by baking at 00 to 1500 ° C.,
Gypsum is added to this calcined product 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. If this amount exceeds 40% by weight, the hardened cement may expand excessively due to the progress of its hydration.

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. If the amount of gypsum is less than 1 part by weight, the cement will set faster than necessary,
Not enough pot life. On the other hand, if it exceeds 30 parts by weight, the setting of the cement is unnecessarily slowed, and the strength development is reduced.

The hydraulic cement composition of the present invention is obtained by mixing limestone powder with the above-mentioned ecocement. The limestone powder to be added has a grain size of 3000 cm ² / blaine specific surface area.
g or more, and preferably contains 10% by weight or more of fine particles of 1 μm or less. By adding such limestone powder, the flowability of ecocement is significantly improved. Here, the function of the limestone powder is considered as follows. That is, limestone powder is more easily crushed than cement particles, and generally has a large amount of fine particles and a broad particle size distribution. For this reason, by mixing the limestone powder, the fine particles of the limestone powder are filled in the voids between the cement particles, and the water originally present in the voids becomes free water, so that the fluidity is improved. In addition, the addition of limestone powder broadens the particle size distribution of the entire hydraulic cement composition, so that the use of the above agent improves the filling property and reduces the bulk of the hydraulic cement composition. As a result, under the condition that the water cement ratio is constant, the amount of free water also increases,
This also improves the fluidity. Furthermore, the addition of limestone powder reduces the proportion of aluminum compounds having remarkable initial hydration activity, so that the water consumed in the initial hydration reaction decreases and free water also improves the flowability. Contribute.

It is pointed out that while the addition of limestone powder has the effect of improving the flowability, it may cause a decrease in strength commensurate with the amount added. However, limestone powder reacts with aluminum compounds to form hydrates,
Ecocement containing a large amount of aluminum compound is less likely to decrease in strength due to the addition of limestone, and is more advantageous in suppressing the decrease in strength due to limestone addition than other cements having a low aluminum content.

The amount of limestone powder to be added is preferably 5 to 40% by weight. When the amount is less than 5% by weight, there is substantially no effect of improving the fluidity. On the other hand, when the amount exceeds 40% by weight, the fluidity is improved but the strength is greatly reduced. In addition, among the components of the limestone powder, it is desirable that the viscosity minerals and the like be as small as possible because they hinder the improvement of the fluidity. But it doesn't matter. In general, there is generally no problem if the CaCO ₃ content is 90% by weight or more.

In the present invention, the ecocement and the limestone powder may be mixed by adding a limestone powder having a predetermined particle size to the finely pulverized ecocement and mixing them by a usual method such as a mixer. And limestone may be ground simultaneously. When both are individually pulverized and mixed, limestone may be finely pulverized in advance by a usual method and further classified as needed.

[0016]

EXAMPLES and COMPARATIVE EXAMPLES Specific examples and comparative examples of the present invention are shown below. In addition, these are illustrations and do not limit this invention. Example 1 54.3% by weight of dried municipal incineration ash, 42.5% by weight of limestone powder, 1.1% by weight of aluminum ash, and 1.1% of clay shown in Table 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 vertical mill to a pulverized Blaine specific surface area of 4000 cm ² / g.
12 parts by weight of anhydrous gypsum was added to 0 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. Samples Nos. 2 to 9 were prepared by mixing limestone powder having the particle size shown in Table 3 with this ecocement at the ratio shown in the table. The limestone powder used here was obtained by grinding limestone having a chemical composition shown in Table 1 to a predetermined particle size using a ball mill. In addition, a predetermined amount of ecocement and limestone powder were mixed using a blade-type mixer. Sample No. 1 was only Ecocement and was shown as a comparative standard. Samples No. ^{2 to} No. 9 used a limestone powder having a Blaine specific surface area of 4700 cm ² / g and containing 10% by weight or more of fine particles having a particle size of 1 μm or less and varying the amount added to ecocement. These samples N
A mortar was manufactured for o.1 to No.9 according to the compounding ratio in Table 4, and its fluidity and strength were evaluated. The liquidity was evaluated using a flow table and a flow value of 15 strokes.
The strength was evaluated based on the compressive strength of 28 days of age. As for the flow value evaluation mortar, 0.8 parts by weight of a polycarboxylic acid type high-performance AE water reducing agent was added to 100 parts by weight of a hydraulic cement composition which is a mixture of limestone powder and ecocement. Table 5 shows the measurement results of the flow value and the strength, and the rate of increase in the flow value and the rate of decrease in the strength with respect to the comparative standard (Sample No. 1).

Compared with the comparison standard of Ecocement alone (Sample No. 1), the samples of the present invention (No. 3 to No. 8) have an increased flow value, and a remarkable effect of improving fluidity is observed. Moreover, the reduction rate of the compressive strength is small. Note that the flow value increases in proportion to the amount of limestone powder added. This is considered to be because the addition of limestone powder improves the particle size distribution and increases free water and the like released from between the cement particles. However, when the amount of the limestone powder added is less than 3% by weight (Sample No. 2), the flow value does not increase, and no substantial effect of improving the fluidity is seen. 5% by weight or more of limestone powder (Sample No. 3
~ No. 8), the flow value increases significantly. On the other hand, when the addition amount of limestone is 40% by weight or less, preferably 30% by weight or less, more preferably 25% by weight or less, the reduction rate of the compressive strength is small. This is presumably because limestone powder reacts with the aluminum compound to form a hydrate, which advantageously acts to suppress a decrease in strength. However, when the amount of limestone powder added is 50% by weight (Sample No. 9)
Indicates that the reduction rate of strength reaches 48% and the absolute value of compressive strength is 3
Since it is below 0 MPa, the strength is insufficient for use as a structural material. For this reason, in order to maintain a practical strength level, the amount of limestone powder to be added is suitably 40% by weight or less.

Example 2 Limestone powder having a particle size shown in Table 6 was used, and the added amount was 25.
Samples No. 10 to No.
Thirteen hydraulic cement compositions were prepared, and flow values and compressive strengths of the mortars manufactured according to the mixing ratios in Table 4 were measured. The results are shown in Table 7. Sample No. 10 used a limestone powder having a Blaine specific surface area of 1000 cm ² / g and a content of fine particles of 1 μm or less of 5% by weight, while Sample Nos. 11 to 13 used a Blaine specific surface area. Is 3500
Limestone powder having a particle size of 11000 cm ² / g and a content of fine particles of 1 μm or less of 10% by weight or more was used. As is evident from the results in Table 7, samples No. 11 to No. 13 all have a large flow value increase rate, and a remarkable fluidity improving effect is observed. On the other hand, in sample No. 10, the increase in the flow value was small, and therefore, the particle size of the limestone powder was such that the Blaine specific surface area was 3000 cm.
It is preferable that the ratio is ² / g and the fine particles having a size of 1 μm or less account for 10% by weight or more.

[0019]

EFFECT OF THE INVENTION The hydraulic cement composition of the present invention solves the drawback of eco-cement in that it is difficult to obtain suitable fluidity, and effectively utilizes waste through expansion of the use of eco-cement manufactured from waste. And it is easy to recycle.

[0020]

[Table 1]

[0021]

[Table 2]

[0022]

[Table 3]

[0023]

[Table 4]

[0024]

[Table 5]

[0025]

[Table 6]

[0026]

[Table 7]

Claims (3)

[Claims] 1. A fired product made 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 characterized by mixing a limestone powder with a hydraulic composition comprising a calcined product containing gypsum and calcium silicate. 2. The mixed limestone powder has an inner ratio of 5 to 40.
The hydraulic cement composition according to claim 1, which is in weight%. 3. The limestone powder has a Blaine specific surface area of 3000.
^{3. The} hydraulic cement composition according to claim 1, wherein the composition is not less than cm ² / g and contains at least 10% by weight of fine particles having a size of 1 μm or less. 4.