JP2005089232A - Method of producing cement composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide technology for utilizing a larger amount of waste or by-products for production of cement without deteriorating the flowability and workability in use. <P>SOLUTION: In the production of a cement composition using inorganic waste containing an aluminum component in high concentration as a part of raw materials, at least a part of the inorganic waste containing the aluminum component in high concentration is fired in a process separated from a firing process of cement clinker to form a specific fired material containing ≥20 wt.% CaO-Al<SB>2</SB>O<SB>3</SB>-2SiO<SB>2</SB>, the remaining part of the inorganic waste which contains Al<SB>2</SB>O<SB>3</SB>in high concentration is used for a raw material for the cement clinker production in the firing process of the cement clinker and the specific fired material, the cement clinker and gypsum are mixed to produce the cement composition. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a novel method for producing a cement composition. Specifically, it is possible to treat a large amount of inorganic waste containing a high concentration of an aluminum component such as Al ₂ O ₃ and to obtain a cement composition having no problem in the physical properties of the resulting cured product. A method for producing a cement composition is provided.

  In recent years, effective use of waste has become an important issue from the viewpoint of global environmental problems. In particular, the method of using waste as a cement manufacturing raw material or fuel and firing cement clinker is attracting attention as the most effective method from the viewpoint of mass processing of the waste, and already uses a lot of waste. Has been proposed (Non-Patent Document 1).

Chemical Equipment Vol.39 No.1 (issued January 1, 1997) 60-65

However, among the above wastes, inorganic wastes such as coal ash, municipal waste incineration ash, blast furnace granulated slag, and blast furnace slow-cooled slag have a higher aluminum content than ordinary cement clinker components. In the case where the amount of inorganic waste containing a large amount of aluminum (hereinafter also referred to as high Al-containing inorganic waste) is increased, tricalcium aluminate (3CaO · Al ₂ O ₃ , among the cement clinker components) The content of (hereinafter abbreviated as C ₃ A) tends to increase. Since this C ₃ A has a high reactivity at the initial stage of hydration, when its content increases, there arises a problem that the fluidity and workability of the cement composition such as cement paste, mortar, concrete and the like are lowered. .

  Therefore, there is a limit to the amount of high Al-containing inorganic waste used in the cement clinker raw material, and the upper limit of the amount used as a normal cement clinker raw material is only about 20% of the total raw material. At present, it is difficult to treat the inorganic waste contained in the cement production facility.

  Accordingly, it has been desired to develop a technique for using more high Al-containing inorganic waste for cement production without reducing the fluidity and workability during use of the resulting cement composition.

The present inventors have conducted intensive research to solve the above problems. As a result, the calcination of cement clinker in a separate step, to produce a calcined product of _{CaO · Al 2 O 3 · 2SiO} 2 containing 20% by weight or more using a high Al-containing inorganic wastes, which cement clinker By mixing with ingredients and gypsum to make a cement composition, a large amount of high Al-containing inorganic waste can be used as a raw material for the cement composition, and there is no problem in the curing characteristics obtained by the cement composition. It is possible to increase the treatment amount of high Al content inorganic waste in the cement composition in addition to the treatment amount of high Al content inorganic waste as a raw material of the cement clinker. As a result, the present invention has been completed.

That is, the present invention calcinates inorganic waste containing an aluminum component at a high concentration to produce a fired product containing CaO.Al ₂ O ₃ .2SiO ₂ as a main component and containing 20% by weight or more. And a cement clinker component and gypsum are mixed.

  The production method of the cement composition of the present invention is a novel production method capable of treating a large amount of inorganic waste containing a high concentration of aluminum components without greatly reducing the fluidity and workability during use. Yes, such a method also provides a new cement admixture.

  Incidentally, conventionally, the upper limit of the amount of waste used in cement production is about 20% in the raw material, but by using the production method of the present invention, the amount of waste in the cement raw material is not adversely affected. It becomes possible to increase the amount of waste used up to about 70% in terms of quantity.

  As described above, the present invention capable of processing a large amount of waste and by-products is extremely valuable not only from an industrial standpoint but also from the viewpoint of global environmental problems.

  Hereinafter, the present invention will be described in more detail.

In the present invention, the high Al-containing inorganic waste is an inorganic waste containing aluminum at a high concentration, for example, 5 wt% or more, generally 10 to 50 wt% in terms of aluminum oxide (Al ₂ O ₃ ). Say things. The high Al-containing inorganic waste preferably contains a calcium component and a silicon component in addition to the aluminum component.

  Specific examples of the high Al-containing inorganic waste include coal ash, municipal waste incineration ash, blast furnace granulated slag, blast furnace slow-cooled slag, and the like, and one or more of these are used in combination. .

The Al ₂ O ₃ content of the high Al-containing inorganic waste is 10% by weight or more, especially 14 to 36% by weight for coal ash, and 10% by weight or more, especially 12 to 30% by weight for municipal waste incineration ash. The blast furnace granulated slag is preferably 10% by weight or more, particularly 12 to 16% by weight, and the blast furnace slow-cooled slag is preferably 10% by weight or more, particularly 12 to 16% by weight.

In the present invention, a high Al content inorganic waste is fired, and a fired product (hereinafter referred to as 20% by weight or more) containing a mineral represented by a composition formula CaO.Al ₂ O ₃ .2SiO ₂ (hereinafter abbreviated as CAS ₂ ). The method for producing the specific fired product is not particularly limited.

  In general, the composition is adjusted by a high Al content inorganic waste alone, a combination of two or more types of high Al content inorganic waste, or a combination of these high Al content inorganic waste and calcium component and / or silicon component. , 1000-1600 ° C., preferably 1100-1500 ° C.

  Examples of the substance containing the calcium component include limestone, quicklime, slaked lime, and the like, and examples of the substance containing the silicon component include quartzite and silica sand. Moreover, as the device, a device capable of high-temperature heating such as a cement kiln can be suitably used.

The aforementioned specific fired product, in addition to the CAS _2, CaO, oxides such as _Al 2 _{O 3} and SiO _2, CaO, _Al 2 _{O 3} and compounds comprising two or more of SiO _{2, SiO} 2, _{al 2 O 3, Fe 2 O} 3, CaO, MgO, Na 2 O, the glass phase consists of _{K 2} O and TiO _2, etc., or there is a case where compounds other than these are present, they, the CAS ₂ Contains 20% by weight or more. In the present invention, it is preferable that the content of CAS ₂ is 50% by weight or more, particularly 70% by weight or more, and other compounds may be present in an amount that does not significantly inhibit the effects of the present invention.

The CAS as _two other compounds, _{specifically, CaO · SiO 2, 3CaO ·} SiO 2, 2CaO · SiO 2, CaO · Al 2 O 3, 3CaO · Al 2 O 3, 3Al 2 O 3 · 2SiO 2, _{2CaO · Fe 2 O 3, 3CaO} · Fe 2 O 3, 2CaO · Al 2 O 3 · SiO 2, Na 2 O · Al 2 O 3 · 6SiO 2, K 2 O · Al 2 O 3 · 6SiO 2 and the like can be mentioned It is done.

  In the present invention, when the above-mentioned specific fired product is added to the cement clinker component and gypsum to form a cement composition, it does not significantly affect the curing characteristics.

  That is, the specific composition has low reactivity after kneading the cement composition obtained by mixing it with water, and hardly participates in the curing characteristics. Therefore, the specific fired product can be contained in a large amount in the cement composition.

In the present invention, the ratio of the specific calcined product in the obtained cement composition is not particularly limited, but the Al ₂ O ₃ content of the cement composition is 15% by weight or less, more preferably 12% by weight. It is preferable to add so that it may become the following.

In the present invention, the cement clinker component to be mixed with the specific fired product is not particularly limited and may be any composition having a known composition. Generally, the composition formula 3CaO · SiO ₂ (hereinafter referred to as C _{3) is used.} 2CaO · SiO ₂ (hereinafter abbreviated as C ₂ S), 3CaO · Al ₂ O ₃ (hereinafter abbreviated as C ₃ A), 4CaO · Al ₂ O ₃ · Fe ₂ O ₃ (hereinafter referred to as C) ₄ ) (Abbreviated as 4AF) is preferred as the main component.

  Minerals or compounds other than these may be contained, but there is no particular problem as long as the effects of the present invention are not impaired.

  Specific examples of cement clinker having a cement clinker component having the above-described composition include various portland cement clinkers such as normal strength, super early strength, moderate heat, and low heat.

  In the present invention, when producing the cement clinker component, by using the high Al content inorganic waste as a part or all of the raw material, the high Al content inorganic waste in the cement composition in a larger amount. It can be used for this.

Incidentally, in contrast to the case where a high Al content inorganic waste is used only as a raw material for the cement clinker component as in the prior art, the high Al content inorganic waste is further mixed in the cement composition as the fired product. Thus, the amount of the high Al-containing inorganic waste used can be improved by about 230%, and the curing characteristics of the cement composition are not particularly problematic. It becomes possible to increase dramatically. In the method for producing a cement composition of the present invention, gypsum is mixed together with the above-mentioned specific fired product and cement clinker component. As such gypsum, one or more of dihydrate gypsum, hemihydrate gypsum, and anhydrous gypsum can be used. The amount of gypsum used is not particularly limited, but it is desirable to adjust the cement so that the SO ₃ content is 1.5 to 10% by weight. If the SO ₃ content is less than 1.5% by weight, abnormal condensation such as rapid setting may occur, which is not preferable. Further, when the SO ₃ content exceeds 10 wt% is not preferable because the strength development and dimensional stability of the cured product is reduced.

  The cement composition of the present invention may contain a small amount of components in addition to the components described above as long as the effects of the present invention are not impaired. Examples of such minor components include inorganic substances such as blast furnace granulated slag, blast furnace slow-cooled slag, fly ash, coal ash, and fine limestone powder.

  In general, the amount of these small components added is preferably adjusted so as to be a ratio of 10% by weight or less in the cement composition.

  In the present invention, the mixing method of each component is not particularly limited. However, a method of mixing a cement clinker component and gypsum and then pulverizing the mixture and pulverizing the specific fired product is preferable.

  In addition, a method of individually pulverizing and mixing each of them, a method of simultaneously pulverizing two arbitrary components and mixing them with the remaining components separately pulverized, a method of simultaneously pulverizing three components, and the like. In addition, as another method, a method of mixing individually pulverized three components at the time of manufacturing paste, mortar and concrete can be employed.

In the present invention, the specific cement surface area of the obtained cement composition is preferably 2000 to 10,000 cm ² / g, more preferably 2500 to 5000 cm ² / g.

  The cement composition of the present invention obtained by the above-described method is mainly used in the state of paste, mortar or concrete. In use, various chemical admixtures such as water, fine aggregates, coarse aggregates, cement dispersants, cement admixtures, inorganic additives, organic additives, etc. that are usually used for these adjustments are used. Is possible.

By the way, the specific fired product containing 20% by weight or more of CAS ₂ has a high effect of improving the fluidity of the cement composition, and can be suitably used as a cement admixture. The CAS ₂ component is generally used as a ceramic raw material and has not been conventionally applied to cement admixtures. However, the present inventors have studied the behavior of CAS _{2 as} a cement admixture. It has been found that even if a large amount of is mixed, the physical properties of the cement composition are not adversely affected, and the fluidity of the cement composition is improved.

  Furthermore, the present inventors have also found that a concrete composition using the cement admixture has small self-shrinkage during the curing process and is excellent in dimensional stability.

That is, according to the present invention is also provided a cement admixture composed mainly of CAS _2.

In addition, the cement admixture mainly composed of CAS ₂ of the present invention is not limited to the above method using the high Al-containing inorganic waste as a raw material, and a method using CAS ₂ produced in nature, A method of mixing a raw material containing CaO, Al ₂ O ₃ and SiO ₂ at a predetermined ratio and baking is arbitrarily used.

In the present invention, the CAS ₂ content in the cement admixture containing CAS ₂ as a main component is preferably 20% by weight or more, and particularly preferably 50% by weight or more.

In the present invention, the specific surface area of the brane as the cement admixture is desirably 2000 to 10000 cm ² / g.

  The cement admixture of the present invention can be mixed with various cements in addition to being used as one component of the cement composition of the present invention. Specifically, various Portland cements such as normal, early strength, ultra-early strength, moderate heat and low heat, various mixed cements in which blast furnace slag, fly ash, or silica is mixed with these Portland cements, and fillers in which limestone fine powder is mixed. A cement, an alumina cement, an eco-cement, etc. are mentioned, These 1 type (s) or 2 or more types can be used.

  The mixing ratio of the cement admixture is not particularly limited, but is 3 to 300 parts by weight, preferably 5 to 150 parts by weight, with respect to 100 parts by weight of cement.

  The cement admixture of the present invention can be mixed with other cement admixtures. Specific examples include blast furnace slag fine powder, fly ash, silica fume, and limestone fine powder.

  The mixing method of these cements and the cement admixture of the present invention is not particularly limited. A method of mixing cement admixture and cement prepared individually, a method of mixing cement admixture in the cement manufacturing process, a method of mixing at the time of manufacturing paste, mortar and concrete, and the like can be mentioned.

  In the present invention, the water powder weight ratio of the concrete composition using the cement admixture is not particularly limited, but is preferably 0.20 to 0.60.

In the present invention, the amount of water contained in the concrete composition is not particularly limited, but is preferably 140 to 185 kg per 1 m ^{3 of} the concrete composition.

  In the present invention, the cement dispersant is not particularly limited as long as it has an effect of dispersing cement. Specific examples of the cement dispersant include water reducing agents, AE water reducing agents, high performance water reducing agents, fluidizing agents, high performance AE water reducing agents, and the like.

  In the present invention, the blending amount of the cement dispersant is not particularly limited. If a suitable composition is illustrated, it will be 0.1-10.0 weight% with respect to the total amount of a cement and a cement admixture, Preferably it is 0.1-5.0 weight%.

  In the present invention, the fine aggregate and coarse aggregate can be used without particular limitation as long as they are generally used for concrete. Specific examples of the fine aggregate include river sand, sea sand, mountain sand, crushed sand, and the like. Specific examples of the coarse aggregate include river gravel, hard sandstone crushed stone, and limestone crushed stone.

  In addition to the cement, cement admixture, fine aggregate, coarse aggregate, cement dispersant and water that constitute the present invention, the concrete composition of the present invention can control the amount of air within a range that does not significantly impair the effects of the present invention. Preparations, setting retarders, setting accelerators, rust inhibitors, separation reducing agents, thickeners, shrinkage reducing agents, expanding materials, mineral fine powders, and the like may be added and blended.

  Hereinafter, although an example explains composition and an effect of the present invention, the present invention is not limited to an example.

(1) Evaluation method of fluidity The time-dependent change in fluidity was measured from 15 minutes to 30 minutes immediately after kneading of the cement paste using the cement composition or cement admixture. The fluidity was evaluated by measuring the paste flow value based on the fluidity test of JASS 15 M-103 “Quality Standard for Self-Leveling Material”.

(2) Evaluation Method of Compressive Strength of Concrete The compressive strength of concrete was measured according to JIS A 1108 “Method for testing compressive strength of concrete”.

(3) Evaluation method of self-shrinkage of concrete Self-shrinkage is “Superfluid Concrete Research Committee Report (II) [Appendix 1] Self-shrinkage test method of high-fluidity concrete” (Japan Concrete Institute, May 1994) It was measured by.

Examples 1-3 and Comparative Examples 1 and 2
Coal ash (Al ₂ O ₃ content: 30.0% by weight) and calcium carbonate are blended so that the weight ratio is coal ash: calcium carbonate = 5: 1, calcined at 1150 ° C. for 2 hours, and Blaine specific surface area 3300 cm A specific fired product containing 83% by weight of CAS ₂ was obtained by grinding to ² / g.

On the other hand, ordinary Portland cement produced using 14.2% by weight of the raw material of the above coal ash and blast furnace slow-cooled slag (Al ₂ O ₃ content: 14.1% by weight) as a cement clinker component. Tont clinker was produced, and 3.4 wt% of gypsum was mixed with the cement clinker component, and then pulverized to a Blaine specific surface area of 3300 cm ² / g to produce a cement.

  Next, the cement and the specific fired product were mixed in the obtained cement composition so that the specific fired product had a ratio shown in Table 1, thereby obtaining a cement composition.

On the other hand, as Comparative Example 1, a cement not mixed with the specific fired product was used. In addition, as Comparative Example 2, a cement clinker was manufactured using coal ash and blast furnace chilled slag as raw materials, and a C ₃ A content of 15% by weight, and gypsum was used at a usage amount of 6.6% by weight. Cement obtained by pulverizing to a specific surface area of 3100 cm ² / g (hereinafter abbreviated as high C ₃ A cement) was used.

  The fluidity of the cement composition and cement was evaluated. In both examples and comparative examples, the weight ratio of cement paste to water powder was 0.50. The results are shown in Table 1.

実施例４〜６及び比較例３及び４
実施例１〜３及び比較例１、２において、セメントペーストの水粉体重量比は０．２７とし、ポリエチレングリコール鎖を有する化合物を主成分とするポリカルボン酸系セメント分散剤を、添加量がセメント組成物重量の１．５重量％となるよう添加した以外は同様にして、流動性の評価を行った。その結果を表２に示す。

Examples 4-6 and Comparative Examples 3 and 4
In Examples 1 to 3 and Comparative Examples 1 and 2, the weight ratio of the cement paste to water powder is 0.27, and the amount of the polycarboxylic acid-based cement dispersant mainly composed of a compound having a polyethylene glycol chain is added. The fluidity was evaluated in the same manner except that it was added to 1.5% by weight of the cement composition. The results are shown in Table 2.

実施例７〜１４
ＣａＯ、Ａｌ_２Ｏ_３及びＳｉＯ_２を原料とし、重量比がＣａＯ：Ａｌ_２Ｏ_３：ＳｉＯ_２＝１：１：２となるよう配合し、１３５０℃で２時間焼成した後、ブレーン比表面積３１５０ｃｍ^２／ｇに粉砕して、ＣＡＳ_２を９５重量％含有する焼成物を製造した。

Examples 7-14
Using CaO, Al ₂ O ₃ and SiO ₂ as raw materials, blended so that the weight ratio is CaO: Al ₂ O ₃ : SiO ₂ = 1: 1: 2, baked at 1350 ° C. for 2 hours, and then has a Blaine specific surface area of 3150 cm A baked product containing 95% by weight of CAS ₂ was produced by grinding to ² / g.

  The cement used in Examples 1 to 3 as a cement admixture made of this fired product was blended so that the proportion in the resulting cement composition was 10, 20, 30, 40% by weight.

  The fluidity of the cement composition and cement was evaluated. In addition, the water powder weight ratio of the cement pastes of Examples 7 to 10 was 0.50. In Examples 11 to 14, the weight ratio of the cement paste to water powder is 0.27, and the polycarboxylic acid-based cement dispersant mainly composed of a compound having a polyethylene glycol chain is added to the cement and the cement admixture. It added so that it might become 1.5 weight% of a total weight. The results are shown in Table 3.

実施例１５〜２２
石炭灰（Ａｌ_２Ｏ_３含有量２４．０重量％）と高炉徐冷スラグ（Ａｌ_２Ｏ_３含有量１４．０重量％）を原料とし、重量比が石炭灰：高炉徐冷スラグ＝６０：４０となるよう配合し、１１５０℃で１時間３０分焼成した後、ブレーン比表面積３４５０ｃｍ^２／ｇに粉砕し、ＣＡＳ_２を８１重量％含有する特定焼成物を得た。

Examples 15-22
Coal ash (Al ₂ O ₃ content 24.0% by weight) and blast furnace slow-cooled slag (Al ₂ O ₃ content 14.0% by weight) are used as raw materials, and the weight ratio is coal ash: blast furnace slow-cooled slag = 60: The resulting mixture was baked at 1150 ° C. for 1 hour 30 minutes, and then pulverized to a Blaine specific surface area of 3450 cm ² / g to obtain a specific fired product containing 81% by weight of CAS ₂ .

  This specific fired product was used as a cement admixture, and was blended in the cement used in Examples 1 to 3 so that it would be 10, 20, 30, 40% by weight.

  The fluidity of the cement composition was evaluated. In addition, the water powder weight ratio of the cement pastes of Examples 15 to 18 was 0.50. In Examples 19 to 22, the weight ratio of the cement paste to water powder is 0.27, and the polycarboxylic acid-based cement dispersant mainly composed of a compound having a polyethylene glycol chain is added to the cement and the cement admixture. It added so that it might become 1.5 weight% of a total weight. The results are shown in Table 4.

コンクリート組成物の圧縮強度と自己収縮を測定した。セメント混和材は、実施例１５〜２２と同様の焼成物をブレーン比表面積４０５０ｃｍ^２／ｇに粉砕したものを使用した。その他の材料は、以下に示すものを使用した。

The compressive strength and self-shrinkage of the concrete composition were measured. As the cement admixture, the same fired product as in Examples 15 to 22 was pulverized to a Blaine specific surface area of 4050 cm ² / g. The other materials shown below were used.

<Materials used>
Ordinary Portland cement (Brain value: 3320 cm ² / g)
Blast furnace slag fine powder (Blaine value: 5970 cm ² / g)
Limestone fine powder (Brain value: 5100 cm ² / g)
Fine aggregate: sea sand (maximum dimension: 5 mm, surface dry density: 2.61 g / cm ³ )
Coarse aggregate: hard sandstone crushed stone (maximum dimension: 20 mm, surface dry density: 2.71 g / cm ³ )
Cement dispersant: polycarboxylic acid-based high-performance AE water reducing agent water (tap water).

Examples 23-25
The water powder weight ratio is 0.30, the mixing ratio of cement admixture is 10, 30 and 40% by weight of the total amount of cement and cement admixture, and water, cement, cement admixture, fine aggregate, coarse bone The compressive strength and self-shrinkage of the concrete composition containing the materials and the cement dispersant in the proportions shown in Table 5 were measured. The results are shown in Table 6.

Examples 26-27
The water powder weight ratio is 0.32, the mixing ratio of cement, cement admixture and blast furnace slag fine powder is 50:10:40 and 50:30:20, water, cement, cement admixture, blast furnace slag fine powder, The concrete composition which mix | blended the fine aggregate, the coarse aggregate, and the cement dispersing agent in the ratio shown in Table 5 was adjusted, and the test similar to Examples 23-25 was implemented. The results are shown in Table 6.

Comparative Example 5
A concrete composition containing water, cement, fine aggregate, coarse aggregate and cement dispersant in the proportions shown in Table 5 was prepared without using cement admixture, and the same tests as in Examples 23 to 25 were performed. did. The results are shown in Table 6.

Comparative Example 6
A concrete composition containing water, cement, blast furnace slag fine powder, fine aggregate, coarse aggregate and cement dispersant in the proportions shown in Table 5 was prepared without using cement admixture, and Examples 23 to 25 and A similar test was conducted. The results are shown in Table 6.

Comparative Example 7
A concrete composition in which water, cement, fine powder of blast furnace slag, fine powder of limestone, fine aggregate, coarse aggregate and cement dispersant were blended in the proportions shown in Table 5 without using a cement admixture. Tests similar to 23-25 were performed. The results are shown in Table 6.

Claims (6)

Firing an inorganic waste containing an aluminum component at a high concentration to produce a calcined product containing 20 wt% or more of CaO.Al ₂ O ₃ .2SiO ₂ , and mixing the calcined product, cement clinker component, and gypsum. A method for producing a cement composition.   The inorganic waste containing the aluminum component at a high concentration is at least one inorganic waste selected from the group consisting of coal ash, municipal waste incineration ash, blast furnace granulated slag, and blast furnace slow-cooled slag. A method for producing a cement composition.   The method for producing a cement composition according to claim 1 or 2, wherein the cement clinker component is obtained by firing inorganic waste containing an aluminum component at a high concentration as part of a cement raw material. A cement admixture comprising a fired product containing 20% by weight or more of CaO · Al ₂ O ₃ · 2SiO ₂ .   A concrete composition comprising cement, a cement admixture according to claim 4, a fine aggregate, a coarse aggregate, a cement dispersant, and water. The concrete composition according to claim 5, which contains fine blast furnace slag powder.