JP2000290050A - Production of artificial lightweight aggregate and artificial lightweight aggregate obtained by the method - Google Patents

Production of artificial lightweight aggregate and artificial lightweight aggregate obtained by the method

Info

Publication number
JP2000290050A
JP2000290050A JP9505499A JP9505499A JP2000290050A JP 2000290050 A JP2000290050 A JP 2000290050A JP 9505499 A JP9505499 A JP 9505499A JP 9505499 A JP9505499 A JP 9505499A JP 2000290050 A JP2000290050 A JP 2000290050A
Authority
JP
Japan
Prior art keywords
lightweight aggregate
artificial lightweight
weight
alkali metal
metal silicate
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP9505499A
Other languages
Japanese (ja)
Inventor
Atsushi Kagakui
敦 加岳井
Takeshi Naganami
武 長南
Shingo Sudo
真悟 須藤
Koji Kawamoto
孝次 川本
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sumitomo Metal Mining Co Ltd
Original Assignee
Sumitomo Metal Mining Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sumitomo Metal Mining Co Ltd filed Critical Sumitomo Metal Mining Co Ltd
Priority to JP9505499A priority Critical patent/JP2000290050A/en
Publication of JP2000290050A publication Critical patent/JP2000290050A/en
Pending legal-status Critical Current

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Classifications

    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B38/00Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof
    • C04B38/009Porous or hollow ceramic granular materials, e.g. microballoons
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02WCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00Technologies for solid waste management
    • Y02W30/50Reuse, recycling or recovery technologies
    • Y02W30/91Use of waste materials as fillers for mortars or concrete

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Processing Of Solid Wastes (AREA)

Abstract

PROBLEM TO BE SOLVED: To provide a method for inexpensively producing high quality artificial lightweight aggregate reduced in the absolute dry specific gravity with the addition of a small quantity of an easily obtainable low cost additive and capable of exhibiting high strength with a relatively low temp. treatment and the artificial light weight aggregate obtained by the method. SOLUTION: The producing method of the artificial lightweight aggregate is by mixing a foaming agent and if necessary, a binder with coal ash of a main raw material and crushing, wet-kneading the crushed material with a m.p. decreasing agent consisting of an alkali metal silicate, molding, drying and firing. The firing is performed at 950-1300 deg.C, the adding quantity of the alkali metal silicate per total aggregate blending materials is >=0.5 wt.% to <=10 wt.%. The foaming agent is composed of iron oxide and at least one kind of silicon carbide or a carbonaceous material. The artificial lightweight aggregate obtained by the method has a absolute dry specific gravity of 0.5-1.5, >=50 kgf compression breaking load and <=15% water absorption.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【0001】[0001]

【発明の属する技術分野】本発明は人工軽量骨材に関
し、具体的には石炭火力発電所や石炭焚きボイラーなど
から発生する石炭灰を、特に土木・建築用の人工軽量骨
材として再資源化して有効利用するための人工軽量骨材
の製造方法およびこの方法により得らた人工軽量骨材に
関するものである。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to artificial lightweight aggregates, and more particularly, to recycling coal ash generated from coal-fired power plants and coal-fired boilers as artificial lightweight aggregates for civil engineering and construction. The present invention relates to a method for producing an artificial lightweight aggregate for effective use and an artificial lightweight aggregate obtained by this method.

【0002】[0002]

【従来の技術】石炭は石油に比べて資源が豊富で単位発
熱量当りの価格も安価なことから、国内のエネルギー政
策により、特に発電用燃料として大幅な使用量の増加が
計画または実施されつつある。その結果、石炭火力発電
所や石炭焚きボイラーなどから発生する石炭灰が、石炭
使用量にほぼ比例して増加している結果、急増する石炭
灰の有効利用法が大きな課題となっている。このような
石炭灰の有効利用としては、人工軽量骨材としての利用
がその需要量の大きさから大量処理の面で適している。
しかしながら、石炭灰はシンターグレート方式で一部が
骨材化されているものの、人工骨材としての利用は国内
では極めて少ないのが現状である。その原因は、石炭火
力発電所や石炭焚きボイラーなどでは、ボイラーの水管
やボイラー壁への灰の付着を軽減するために、高融点の
灰を発生する石炭を選択して使用していることにある。
2. Description of the Related Art Coal has abundant resources compared to petroleum and a low price per unit calorific value. Therefore, the domestic energy policy is planning or implementing a large increase in the amount of fuel used especially as fuel for power generation. is there. As a result, the amount of coal ash generated from coal-fired power plants and coal-fired boilers has increased almost in proportion to the amount of coal used. As effective utilization of such coal ash, utilization as artificial lightweight aggregate is suitable in terms of mass processing because of its large demand.
However, although coal ash is partially aggregated by the sinter great method, its use as artificial aggregate is extremely small in Japan at present. The cause is that coal-fired power plants and coal-fired boilers use coal that generates high melting point ash in order to reduce the adhesion of ash to boiler water pipes and boiler walls. is there.

【0003】すなわち石炭火力発電所や石炭焚きボイラ
ーなどから発生する石炭灰は、一般的には融点が高く、
軽量骨材化するには低融点の粘土や頁岩を多量に混合し
て焼成しなければならない。しかしこれらの粘土や頁岩
を多量に確保するのが困難であること、これらの粘土や
頁岩を採掘・運搬・前処理・混合するのに多くの工程と
費用を要する結果、人工軽量骨材の製造コストが高くな
っていること、さらには単位製品当りの石炭灰の使用率
が低いことから石炭灰の有効利用上好ましくないこと、
また石炭灰を使用して得られた人工軽量骨材の絶乾比重
が1.3〜1.4程度であって用途が制限されてしま
い、この絶乾比重がより小さく軽質で強度を有する人工
軽量骨材を製造する技術が未だに開発されていないこと
などの問題から石炭灰を人工軽量骨材として有効に再利
用することがなされていなかった。
That is, coal ash generated from a coal-fired power plant or a coal-fired boiler generally has a high melting point,
In order to make a lightweight aggregate, it is necessary to mix a large amount of low melting point clay or shale and fire it. However, it is difficult to secure a large amount of these clays and shale, and many steps and costs are required to mine, transport, pre-process, and mix these clays and shale. That the cost is high, and that the utilization rate of coal ash per unit product is low,
In addition, the absolute dry specific gravity of the artificial lightweight aggregate obtained by using coal ash is about 1.3 to 1.4, which limits the application. The artificial dry aggregate having a smaller absolute dry specific gravity and a lighter and stronger strength is used. Coal ash has not been effectively reused as artificial lightweight aggregate due to problems such as the fact that the technology for producing lightweight aggregate has not been developed yet.

【0004】[0004]

【発明が解決しようとする課題】本発明はこのような実
状を考慮してなされたものであり、入手が容易で低価格
な添加剤を少量添加することによい絶乾比重を小さくで
き、比較的低温な処理でも高強度を発現し、かつ高品質
な人工軽量骨材を安価に製造する方法およびこの方法に
より得られた人工軽量骨材を提供することを目的とする
ものである。
DISCLOSURE OF THE INVENTION The present invention has been made in view of such circumstances, and can reduce the absolute dry specific gravity, which is suitable for adding a small amount of easily available and inexpensive additives. It is an object of the present invention to provide a method for inexpensively producing a high-quality artificial lightweight aggregate that exhibits high strength even at a low temperature treatment and an artificial lightweight aggregate obtained by this method.

【0005】[0005]

【課題を解決するための手段】本発明者らは、単位製品
当たりの石炭灰の使用率を増加してその有効利用率を高
め、絶乾比重を小さくできるとともに高強度を発現で
き、かつ安価な製造方法について鋭意検討した結果、主
原料の石炭灰に、発泡剤と、必要に応じて粘結剤と、ア
ルカリ金属珪酸塩からなる融点降下剤とを混合すること
により上記課題を解決し得ることを見出し本発明を完成
するに至った。
Means for Solving the Problems The present inventors have increased the use rate of coal ash per unit product to increase its effective utilization rate, can reduce the absolute dry specific gravity, can exhibit high strength, and can reduce the cost. As a result of intensive studies on a suitable production method, the above problem can be solved by mixing a foaming agent, a binder if necessary, and a melting point depressant composed of an alkali metal silicate into coal ash as a main raw material. This led to the completion of the present invention.

【0006】すなわち上記目的を達成するため本発明の
第1の実施態様は、主原料の石炭灰に、発泡剤と、必要
に応じて粘結剤を混合して粉砕し、該粉砕物をアルカリ
金属珪酸塩からなる融点降下剤と湿式混練した後、成型
し、ついで乾燥・焼成する人口軽量骨材の製造方法を特
微とするものであり、また前記焼成を950℃〜130
0℃の温度範囲で実施し、さらに全骨材配合原料に対す
る前記アルカリ金属珪酸塩の添加量は、アルカリ金属珪
酸塩に含有するトータルのアルカリ金属酸化物換算で
0.5重量%以上で10重量%以下であり、さらにまた
前記発泡剤が、酸化鉄と、炭化珪素または炭材のうち少
なくとも1種とからなることを特徴とする。
That is, in order to achieve the above object, in a first embodiment of the present invention, coal ash as a main raw material is mixed with a foaming agent and, if necessary, a binder, and ground, and the ground material is treated with an alkali. The method is characterized by a method for producing an artificial lightweight aggregate, which is formed by wet-kneading with a melting point depressant made of a metal silicate, molding, and then drying and firing.
The process was carried out at a temperature of 0 ° C., and the amount of the alkali metal silicate added to the total raw material for the aggregate was 0.5% by weight or more and 10% by weight in terms of the total alkali metal oxide contained in the alkali metal silicate. % Or less, and the foaming agent is made of iron oxide and at least one of silicon carbide and carbonaceous material.

【0007】また本発明の第2の実施態様は、上記した
第1の実施態様に係る方法により得られ、かつ絶乾比重
が0.5〜1.5、一軸圧縮破壊荷重が50kgf以上
で、吸水率が15%以下である人工軽量骨材を特徴とす
るものである。
[0007] A second embodiment of the present invention is obtained by the method according to the first embodiment, and has an absolute dry specific gravity of 0.5 to 1.5, a uniaxial compressive breaking load of 50 kgf or more, It is characterized by an artificial lightweight aggregate having a water absorption of 15% or less.

【0008】[0008]

【発明の実施の形態】以下本発明の詳細およびその作用
についてさらに具体的に説明する。本発明は、アルカリ
金属珪酸塩からなる融点降下剤を主原料の石炭灰に添加
することにより、石炭灰の融点を950℃〜1300
℃、好ましくは1000℃〜1250℃の工業的に焼成
し易い温度に低下させ、かつ発泡剤として酸化鉄と、炭
化珪素および/または石炭やコークスなどの炭材を添加
することによって絶乾比重が0.5〜1.5程度の強度
の高い人工軽量骨材を製造する方法を特徴とするもので
ある。なお炭材は焼成時の造粒したペレット内部の還元
状態の調整にも機能する。
BEST MODE FOR CARRYING OUT THE INVENTION The details of the present invention and its operation will be described more specifically below. The present invention adds the melting point depressant consisting of an alkali metal silicate to coal ash as a main raw material, so that the melting point of coal ash is from 950 ° C. to 1300 ° C.
° C, preferably 1000 ° C to 1250 ° C, and the absolute dry specific gravity is lowered by adding iron oxide and a carbon material such as silicon carbide and / or coal or coke as a foaming agent. It is characterized by a method for producing an artificial lightweight aggregate having a high strength of about 0.5 to 1.5. The carbonaceous material also functions to adjust the reduced state inside the granulated pellets during firing.

【0009】まず本発明に使用する主原料としての石炭
灰は特に限定されるものでなく、例えばフライアッシュ
とシンダアッシュの混合物である原粉、JIS A62
01に適合するようなフライアッシュ、粗粉、クリンカ
アッシュを含む全ての石炭灰を用いることができる。ま
た前記石炭灰の粒径にも特に影響されない。
First, coal ash as a main raw material used in the present invention is not particularly limited. For example, raw powder which is a mixture of fly ash and synda ash, JIS A62
All coal ash can be used, including fly ash, coarse powder, clinker ash, etc., that meet 01. Also, there is no particular effect on the particle size of the coal ash.

【0010】つぎに本発明で用いる発泡剤は酸化鉄と、
炭化珪素または炭材のうち少なくとも1種とからなるも
のであり、人工軽量骨材の絶乾比重を0.5〜1.5程
度に制御するために添加する。発泡剤としては、前記効
果を発揮するものであれば特に限定されないが、例えば
酸化鉄の中でも酸化度の高いヘマタイトが好ましい。酸
化鉄の平均粒径は特に限定されないが、焼成中の炭材に
よる脱酸素反応を促進するために10μm以下とするこ
とが好ましい。また骨材配合原料の全体に対する好まし
いFe添加量は、1重量%〜10重量%である。
その理由は1重量%未満では発泡剤としての効果が少な
く、人工軽量骨材の絶乾比重を0.5〜1.5程度まで
制御できず、他方10重量%を超えて添加しても発泡に
よる軽量化の効果はそれ以上増加しないからである。な
お酸化鉄の比重は石炭灰と比較して著しく大きく、発泡
が促進されないと人工軽量骨材の比重を増加させること
になる。
Next, the blowing agent used in the present invention is iron oxide,
It is composed of at least one of silicon carbide and carbonaceous materials, and is added to control the absolute dry specific gravity of the artificial lightweight aggregate to about 0.5 to 1.5. The foaming agent is not particularly limited as long as it exerts the above-mentioned effects. For example, hematite having a high oxidation degree is preferable among iron oxides. The average particle size of the iron oxide is not particularly limited, but is preferably 10 μm or less in order to promote a deoxygenation reaction by the carbon material during firing. Further, the preferable addition amount of Fe 2 O 3 to the whole of the aggregate compounding raw material is 1% by weight to 10% by weight.
The reason is that if the content is less than 1% by weight, the effect as a foaming agent is small, and the absolute dry specific gravity of the artificial lightweight aggregate cannot be controlled to about 0.5 to 1.5. This is because the effect of weight reduction by the above does not increase any more. The specific gravity of iron oxide is significantly higher than that of coal ash, and if foaming is not promoted, the specific gravity of the artificial lightweight aggregate will increase.

【0011】また炭化珪素はペレットの発泡を促進させ
る効果がある。まず造粒したぺレットが加熱されて多量
の液相が生成されたときに、炭化珪素と酸化鉄が効率よ
く反応してCO、COが発生する。そしてこれらのガ
スが液相中で捕捉され、ペレットの発泡が促進されるの
である。骨材配合原料の全体に対する炭化珪素の添加量
は、0.1重量%〜1重量%であることが好ましい。す
なわち添加量が0.1重量%未満では絶乾比重が1.5
以下の骨材が得られず軽量化ができず、他方1重量%を
超えても軽量効果はそれ以上増大しないためである。さ
らに炭材としては石炭やコークスを使用でき、その効果
は小さいものの、酸化鉄と反応して発泡作用といった機
能を発揮する。したがって炭化珪素の一部を炭材に置き
換えたりすることが可能である。なお炭材は焼成中のペ
レット内部の還元度を調整する効果が大である。骨材配
合原料の全体に対する炭材の添加量は、0.2重量%〜
10重量%であることが好ましい。すなわち添加量が
0.2重量%未満では発泡による軽量化の効果が得られ
ず、他方10重量%を超えて添加しても発泡膨張による
軽量化効果は増加せず、逆に未燃焼の炭素がペレット内
部に残留して人工軽量骨材の強度を低下させる可能性が
あるからである。
Silicon carbide has the effect of promoting the foaming of pellets. First, when the granulated pellet is heated to generate a large amount of liquid phase, silicon carbide and iron oxide react efficiently to generate CO and CO 2 . Then, these gases are trapped in the liquid phase, and the foaming of the pellets is promoted. It is preferable that the amount of silicon carbide to be added to the whole of the aggregate compounding raw material is 0.1% by weight to 1% by weight. That is, when the addition amount is less than 0.1% by weight, the absolute dry specific gravity is 1.5.
This is because the following aggregates cannot be obtained and the weight cannot be reduced. On the other hand, even if the weight exceeds 1% by weight, the lightening effect is not further increased. Further, coal and coke can be used as the carbonaceous material, and although the effect is small, it reacts with iron oxide to exert a function such as a foaming action. Therefore, it is possible to replace a part of silicon carbide with a carbon material. The carbon material has a great effect of adjusting the degree of reduction inside the pellets during firing. The amount of the carbonaceous material added to the whole of the raw material for the aggregate is 0.2% by weight or more.
Preferably it is 10% by weight. That is, if the addition amount is less than 0.2% by weight, the effect of weight reduction by foaming cannot be obtained. On the other hand, if the addition amount exceeds 10% by weight, the effect of weight reduction by foaming expansion does not increase. This is because it may remain inside the pellet and reduce the strength of the artificial lightweight aggregate.

【0012】また粘結剤は後述するアルカリ金属珪酸塩
がその機能を有するため、特に新たに粘結剤を添加しな
くてもよいが、必要に応じて造粒物の成型性と強度を付
与するために添加する。粘結剤の種類は特に限定されな
いが、例えばベントナイトなどの無機類、澱粉、糖蜜、
リグニン、ポリビニルアルコール、メチルセルロース、
天然ゴム、パルプ廃液などの有機類が挙げられる。また
その添加量も特に限定されないが、添加効果およびコス
トを考慮すると0.5重量%〜10重量%の範囲が好ま
しい。
Since the alkali metal silicate described below has the function of the binder, it is not necessary to add a new binder, but if necessary, it can impart the moldability and strength of the granulated material. To be added. The type of the binder is not particularly limited, for example, inorganics such as bentonite, starch, molasses,
Lignin, polyvinyl alcohol, methyl cellulose,
Organics such as natural rubber and pulp waste liquid are exemplified. The amount of addition is not particularly limited, but is preferably in the range of 0.5% by weight to 10% by weight in consideration of the effect of addition and cost.

【0013】つぎに本発明において使用する融点降下剤
について以下に記述する。石炭灰は、液相を生成して焼
結する温度が1400℃〜1500℃と極めて高い場合
が多い。人工軽量骨材を1400℃〜1500℃で焼成
することは、焼成設備の耐火度やエネルギーコストおよ
び発泡剤の選定が困難な点で実用的ではない。従来この
ような高耐火度の原料を焼成する場合には、融点降下剤
としてアルカリ金属類を多く含む低耐火度の粘土や頁岩
などの天然鉱物を多量に加える方法が一般的であった。
本発明者らは粘土、頁岩類の添加効果を種々検討した結
果、これらを構成する成分の中でアルカリ金属類が少量
で液相温度を著しく低下することを確認した。このよう
な液相温度の低下効果を発揮する元素は、前記アルカリ
に限らず低融点酸化物を構成する元素、例えば硼素、鉛
などのいずれのものでもその効果を発揮することを確認
している。
Next, the melting point depressant used in the present invention will be described below. Coal ash often has an extremely high temperature of 1400 ° C. to 1500 ° C. for forming and sintering a liquid phase. Firing the artificial lightweight aggregate at 1400 ° C. to 1500 ° C. is not practical in terms of the fire resistance of the firing equipment, energy cost, and difficulty in selecting a foaming agent. Conventionally, when baking such a high refractory raw material, a method of adding a large amount of a natural mineral such as low refractory clay or shale containing a large amount of alkali metals as a melting point depressant has been generally used.
The present inventors have conducted various studies on the effects of adding clay and shale, and as a result, it has been confirmed that a small amount of alkali metals among these constituents significantly lowers the liquidus temperature. It has been confirmed that the element exhibiting the effect of lowering the liquidus temperature is not limited to the above-described alkali, and that any element constituting the low-melting oxide, such as boron or lead, exhibits the effect. .

【0014】本発明者らは、より安価な製造方法につい
てさらに検討した結果、アルカリ金属珪酸塩が融点降下
剤となり得るという知見を得た。本発明で用いるアルカ
リ金属珪酸塩は特に限定されるものでなく、例えばM
O・nSiO・mHO(M:ナトリウム、カリウ
ム、リチウムなど)あるいはその無水塩が挙げられる
が、コストの点からナトリウム塩が好ましい。
As a result of further study of a less expensive production method, the present inventors have found that an alkali metal silicate can be used as a melting point depressant. Alkali metal silicate used in the present invention is not specifically limited, for example, M 2
O · nSiO 2 · mH 2 O (M: sodium, potassium, lithium, etc.) or its but anhydride salts, sodium salts from the viewpoint of cost are preferred.

【0015】本発明に係る人工軽量骨材において、骨材
配合原料の全体に対するアルカリ金属珪酸塩の好ましい
添加量は、アルカリ金属珪酸塩中に含まれるトータルの
アルカリ金属酸化物換算で0.5重量%以上で10重量
%以下である。これは石炭灰の化学組成が炭種により異
なるものの、SiO:40〜75重量%、Al
:15〜35重量%、NaO:0.2〜2重量
%、KO:0.2〜4重量%からなり、前記アルカリ
金属珪酸塩の添加量によって融点降下が大きくなり、か
つ溶化する温度領域も長くなること、および骨材の焼成
特性と石炭灰利用率の向上の観点からである。そして添
加量を上記範囲とした理由は、0.5重量%未満では融
点降下の効果が十分に発揮されず、他方10重量%を超
えて添加してもそれ以上の格別な効果が得られず、かえ
ってアルカリ金属珪酸塩の使用量の増加によってコスト
高となるとともに石炭灰の利用率が低下するため好まし
くないからである。
In the artificial lightweight aggregate according to the present invention, the aggregate
Preferable alkali metal silicate with respect to the whole compounding raw material
The amount of addition depends on the total amount contained in the alkali metal silicate.
10 weight% at 0.5% or more in terms of alkali metal oxide
% Or less. This is because the chemical composition of coal ash differs depending on the type of coal.
Although, SiO2: 40-75% by weight, Al
2O 3: 15 to 35% by weight, Na2O: 0.2-2 weight
%, K2O: 0.2 to 4% by weight, said alkali
The melting point drop increases with the amount of metal silicate added.
The temperature range for solubilization becomes longer, and the firing of aggregate
This is from the viewpoint of improving characteristics and coal ash utilization. And annex
The reason for setting the addition amount in the above range is that if the addition amount is less than 0.5% by weight,
The effect of point descent is not fully exhibited, and on the other hand, exceeds 10% by weight
Even if it is added, no more special effect can be obtained,
Costs due to increased use of alkali metal silicates
High and the utilization rate of coal ash decreases.
Because it is not.

【0016】本発明に用いる粉砕方法は、混合した骨材
配合原料が平均粒径30μm以下、好ましくは20μm
以下まで微粉砕できるものであればいずれの方法でもよ
く、例えばポットミル、振動ミル、遊星ミルなどのボー
ルミル、衝突式のジェット粉砕機、ターボ粉砕機などが
挙げられる。つぎに主原料の石炭灰および発泡剤と、必
要に応じて粘結剤との混合粉砕物はアルカリ金属珪酸塩
からなる融点降下剤と混練するが、採用する混練方法は
特に限定されず公知の混練装置を用いることができる。
ここでアルカリ金属珪酸塩の添加量によっては混練水を
添加しなくてもよいので、混練をより容易に行うことも
できる。引き続き実施される成型方法としては、所定の
径になるように成型できるものであれば特に限定されず
公知の成型装置を用いると簡便である。なおアルカリ金
属珪酸塩は粘結剤としての機能を有するので、新たに粘
結剤を添加しなくても成型をより容易に行うことができ
る。
In the pulverization method used in the present invention, the mixed aggregate-mixed raw material has an average particle size of 30 μm or less, preferably 20 μm or less.
Any method may be used as long as it can be finely pulverized to the following, and examples thereof include a ball mill such as a pot mill, a vibration mill, and a planetary mill, a collision-type jet pulverizer, and a turbo pulverizer. Next, the mixed and pulverized product of the main raw material coal ash and the foaming agent and, if necessary, the binder is kneaded with a melting point depressant composed of an alkali metal silicate, but the kneading method to be employed is not particularly limited and a known kneading method is used. A kneading device can be used.
Here, kneading water may not be added depending on the amount of alkali metal silicate added, so that kneading can be performed more easily. The molding method to be subsequently performed is not particularly limited as long as it can be molded to a predetermined diameter, and it is convenient to use a known molding device. In addition, since an alkali metal silicate has a function as a binder, molding can be performed more easily without newly adding a binder.

【0017】また焼成法は特に限定されないが、例えば
連続操業や品質の均一性を勘案すればロータリーキルン
を用いることが好ましく、所望とする骨材特性に合わせ
て雰囲気を任意に選択できる。例えば燃焼ガス中の酸素
濃度を3%〜12%、焼成帯温度を950℃〜1300
℃、好ましくは1000℃〜1250℃とし、かつ前記
焼成帯温度での成型体の滞留時間を10分間〜120分
間となるようにキルンの勾配、回転数、ダムの設置や内
径といったキルン構造などを勘案してロータリーキルン
を操作することが好ましい。なお焼成前に施す乾燥法も
特に限定されるものでないが、場合によっては成型体を
直接ロータリーキルンに投入して、当該ロータリーキル
ン内にて乾燥と焼成を同時に行うこともできる。
Although the firing method is not particularly limited, for example, a rotary kiln is preferably used in consideration of continuous operation and uniformity of quality, and the atmosphere can be arbitrarily selected according to desired aggregate characteristics. For example, the oxygen concentration in the combustion gas is 3% to 12%, and the firing zone temperature is 950 ° C to 1300 ° C.
C., preferably 1000 ° C. to 1250 ° C., and the kiln gradient, the number of rotations, the kiln structure such as the dam installation and the inner diameter, etc., so that the residence time of the molded body at the firing zone temperature is 10 minutes to 120 minutes. It is preferable to operate the rotary kiln taking into account. The drying method to be performed before firing is not particularly limited. However, in some cases, the molded body can be directly charged into a rotary kiln, and drying and firing can be simultaneously performed in the rotary kiln.

【0018】[0018]

【実施例】以下実施例および比較例により本発明をさら
に説明する。ただし、本発明は下記実施例に限定される
ものでない。また用いた石炭灰は、SiO:56.2
0重量%、Al:32.10重量%、Fe
:3.57重量%、CaO:0.59重量%、M
gO:1.40重量%、NaO:0.22重量%、K
O:0.48重量%を主成分とするものである。 [実施例1]石炭灰87.5重量%、ベントナイト5重
量%、ヘマタイト5重量%、炭化珪素0.5重量%、コ
ークス2重量%からなる骨材配合原料を、ボールミルに
て平均粒径20μmに混合粉砕した。該粉砕物の全量に
対してアルカリ金属珪酸塩として市販の3号水ガラスを
42.1重量%(NaO=4重量%)添加して混練し
た後、押出成型して105℃で通風乾燥し、ついでロー
タリーキルン(煉瓦内径400mm×長さ6000m
m)に供給して、燃焼ガス中の酸素濃度10%、101
0℃の条件下で10分間焼成して人工軽量骨材を調製し
た。得られた人工軽量骨材の評価として、絶乾比重と吸
水率はJIS A1110に基づいて測定し、また一軸
圧縮破壊荷重により圧潰強度を測定した。なお圧潰強度
は圧潰試験機によって直径10mmの各骨材について測
定し、その平均値を求めた。得られた測定結果を下記す
る表1に示す。
The present invention will be further described below with reference to examples and comparative examples. However, the present invention is not limited to the following examples. The coal ash used was SiO 2 : 56.2.
0% by weight, Al 2 O 3 : 32.10% by weight, Fe
2 O 3 : 3.57% by weight, CaO: 0.59% by weight, M
gO: 1.40 wt%, Na 2 O: 0.22 wt%, K
2 O: 0.48% by weight as a main component. Example 1 An aggregate-mixed raw material composed of 87.5% by weight of coal ash, 5% by weight of bentonite, 5% by weight of hematite, 0.5% by weight of silicon carbide and 2% by weight of coke was averaged in a ball mill to have an average particle diameter of 20 μm. And pulverized. After adding 42.1% by weight (Na 2 O = 4% by weight) of commercially available No. 3 water glass as an alkali metal silicate to the total amount of the pulverized product, kneading, extrusion molding and ventilation drying at 105 ° C. And then a rotary kiln (brick inner diameter 400mm x length 6000m
m), the oxygen concentration in the combustion gas is 10%, 101
The artificial lightweight aggregate was prepared by firing at 0 ° C. for 10 minutes. As the evaluation of the obtained artificial lightweight aggregate, the absolute dry specific gravity and the water absorption were measured based on JIS A1110, and the crushing strength was measured by a uniaxial compressive breaking load. The crushing strength was measured for each aggregate having a diameter of 10 mm by a crushing tester, and the average value was obtained. The obtained measurement results are shown in Table 1 below.

【0019】[実施例2〜9]骨材配合原料を、石炭灰
89.5重量%、ベントナイト5重量%、ヘマタイト5
重量%、炭化珪素0.5重量%、コークス0重量%とし
た以外は実施例1と同様にして実施例2を、骨材配合原
料を、石炭灰90.5重量%、ベントナイト2重量%、
へマタイト5重量%、炭化珪素0.5重量、コークス2
重量%とした以外は実施例1と同様にして実施例3を、
骨材配合原料を、石炭灰92.5重量%、ベントナイ卜
0重量%、ヘマタイト5重量%、炭化珪素0.5重量
%、コークス2重量%とした以外は実施例1と同様にし
て実施例4を、ロークリーキルンの温度を1030℃、
1050℃とした以外は実施例1と同様にして、それぞ
れ実施例5、実施例6を得た。なお実施例2〜6におい
て市販の3号水ガラスの添加量は実施例1と同様とし
た。
[Examples 2 to 9] Aggregate-mixed raw materials were 89.5% by weight of coal ash, 5% by weight of bentonite, and 5% by weight of hematite.
Example 2 was repeated in the same manner as in Example 1 except that the weight of the raw material was changed to 0.5% by weight, silicon carbide and 0% by weight of coke.
Hematite 5% by weight, Silicon carbide 0.5%, Coke 2
Example 3 was repeated in the same manner as in Example 1 except that the weight% was used.
Example 1 was repeated in the same manner as in Example 1 except that the raw material for the aggregate was 92.5% by weight of coal ash, 0% by weight of bentonite, 5% by weight of hematite, 0.5% by weight of silicon carbide and 2% by weight of coke. 4, the temperature of the low-kill kiln is 1030 ° C,
Example 5 and Example 6 were obtained in the same manner as in Example 1 except that the temperature was changed to 1,050 ° C. In Examples 2 to 6, the amount of commercially available No. 3 water glass was the same as in Example 1.

【0020】さらに実施例1と同様の骨材配合原料に対
する市販の3号水ガラスの添加量を8.4重量%(Na
O=0.8重量%)として水を添加して混練し、ロー
タリーキルンでの焼成温度を1170℃とした以外は実
施例1と同様にして実施例7を、市販の3号水ガラスの
添加量を21.1重量%(NaO=2重量%)とし、
ロータリーキルンでの焼成温度を1030℃、1050
℃とした以外は実施例1と同様にして、それぞれ実施例
8、実施例9を得た。
Further, the amount of the commercially available No. 3 water glass added to the same aggregate-mixed raw material as in Example 1 was 8.4% by weight (Na
Water was added and kneaded as 2 O = 0.8 wt%), Example 7 in the same manner as in Example 1 except that the firing temperature was 1170 ° C. in a rotary kiln, the addition of commercial water glass No. 3 Amount 21.1% by weight (Na 2 O = 2% by weight)
The firing temperature in a rotary kiln is 1030 ° C., 1050
Example 8 and Example 9 were obtained in the same manner as in Example 1 except that the temperature was changed to ° C.

【0021】[比較例1〜2]実施例1においてロータ
リーキルンでの焼成温度を900℃とした以外は実施例
1と同様にして比較例1を、市販の3号水ガラスの添加
量を2.1重量%(NaO=0.2重量%)とし水を
添加して混練し、ロータリーキルンの焼成温度を119
0℃とした以外は実施例1と同様にして比較例2を得
た。実施例2〜9および比較例1〜2により得られた人
工軽量骨材についても実施例1と同様な評価試験を行
い、その測定結果を下記する表1に併せて示す。
Comparative Examples 1 and 2 Comparative Example 1 was repeated in the same manner as in Example 1 except that the sintering temperature in the rotary kiln was changed to 900 ° C. 1 wt% (Na 2 O = 0.2 wt%) and water was added and kneaded, the sintering temperature of the rotary kiln 119
Comparative Example 2 was obtained in the same manner as in Example 1 except that the temperature was changed to 0 ° C. The same evaluation test as in Example 1 was performed on the artificial lightweight aggregates obtained in Examples 2 to 9 and Comparative Examples 1 and 2, and the measurement results are shown in Table 1 below.

【0022】[0022]

【表1】 [Table 1]

【0023】表1から分かる通り、実施例1によれば絶
乾比重が1.18、圧潰強度が69kgf、吸水率が1
2.9%の人工軽量骨材が得られた。また、実施例1〜
5、7〜9によれば絶乾比重が1〜1.5、吸水率が1
5%以下で、かつ圧潰強度が60kgfを超える高強度
の人工軽量骨材が得られた。また実施例6によれば絶乾
比重が1未満でも市販の人工軽量骨材と同等の圧潰強度
を有し、かつ吸水率も12.6%の骨材が得られた。こ
れに対して比較例1によれば焼成温度が低いために発泡
が不十分である結果、絶乾比重が1.5以下の人工軽量
骨材が得られず、また比較例2によればアルカリ金属珪
酸塩の添加量が少ないために融点降下が不十分である結
果、絶乾比重が1.5以下の人工軽量骨材が得られなか
った。
As can be seen from Table 1, according to Example 1, the absolute dry specific gravity was 1.18, the crush strength was 69 kgf, and the water absorption was 1
2.9% of artificial lightweight aggregate was obtained. Further, Examples 1 to
According to 5, 7 to 9, the absolute dry specific gravity is 1 to 1.5 and the water absorption is 1
A high-strength artificial lightweight aggregate having a crushing strength of 5% or less and a crushing strength exceeding 60 kgf was obtained. In addition, according to Example 6, an aggregate having a crushing strength equivalent to that of a commercially available artificial lightweight aggregate and a water absorption of 12.6% was obtained even when the absolute dry specific gravity was less than 1. On the other hand, according to Comparative Example 1, as a result of insufficient foaming due to a low firing temperature, an artificial lightweight aggregate having an absolute dry specific gravity of 1.5 or less was not obtained. As a result of insufficient melting point drop due to a small amount of metal silicate added, an artificial lightweight aggregate having an absolute dry gravity of 1.5 or less could not be obtained.

【0024】[0024]

【発明の効果】以上述べた通り本発明によれば、石炭火
力発電所や石炭焚きボイラーなどから発生する石炭灰を
原料として極めて軽質で強度が高く、かつ高品質な人工
軽量骨材を低コストで効率的に生産することができ、し
たがって産業廃棄物を埋め立てて処理することなく、特
に軽量化を必要とする土木・建築材料などに再資源化で
きることから、環境の保全とエネルギーの安定供給に多
大な効果を奏することが可能となった。
As described above, according to the present invention, an extremely light, high-strength, high-quality artificial lightweight aggregate can be produced at a low cost using coal ash generated from a coal-fired power plant or a coal-fired boiler as a raw material. Can be produced efficiently and without having to reclaim and dispose of industrial waste.In particular, it can be recycled into civil engineering and building materials that require lighter weight. A great effect can be achieved.

───────────────────────────────────────────────────── フロントページの続き (72)発明者 須藤 真悟 千葉県市川市中国分3−18−5 住友金属 鉱山株式会社中央研究所内 (72)発明者 川本 孝次 千葉県市川市中国分3−18−5 住友金属 鉱山株式会社中央研究所内 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Shingo Sudo 3-18-5, China, Ichikawa, Chiba Sumitomo Metal Mining Co., Ltd. Central Research Laboratory (72) Inventor Koji Kawamoto 3-18-, China, Ichikawa, Chiba 5. Sumitomo Metal Mining Co., Ltd. Central Research Laboratory

Claims (6)

【特許請求の範囲】[Claims] 【請求項1】 主原料の石炭灰に、発泡剤を混合して粉
砕し、該粉砕物をアルカリ金属珪酸塩からなる融点降下
剤と湿式混練した後、成型し、ついで乾燥・焼成するこ
とを特微とする人工軽量骨材の製造方法。
1. A method of mixing a coal ash as a main raw material with a foaming agent, pulverizing the mixture, wet-kneading the pulverized material with a melting point depressant comprising an alkali metal silicate, molding, and then drying and firing. A special method of manufacturing artificial lightweight aggregate.
【請求項2】 前記石炭灰に、発泡剤とともに粘結剤を
混合することを特微とする請求項1記載の人工軽量骨材
の製造方法。
2. The method for producing an artificial lightweight aggregate according to claim 1, wherein a binder is mixed with the coal ash together with a foaming agent.
【請求項3】 前記焼成を950℃〜1300℃の温度
範囲で実施することを特徴とする請求項1または2記載
の人工軽量骨材の製造方法。
3. The method for producing an artificial lightweight aggregate according to claim 1, wherein the firing is performed in a temperature range of 950 ° C. to 1300 ° C.
【請求項4】 全骨材配合原料に対する前記アルカリ金
属珪酸塩の添加量は、アルカリ金属珪酸塩に含有するト
ータルのアルカリ金属酸化物換算で0.5重量%以上で
10重量%以下であることを特徴とする請求項1〜3の
いずれか1項記載の人工軽量骨材の製造方法。
4. The amount of the alkali metal silicate to be added to the total raw material of the aggregate is 0.5% by weight or more and 10% by weight or less in terms of the total alkali metal oxide contained in the alkali metal silicate. The method for producing an artificial lightweight aggregate according to any one of claims 1 to 3, characterized in that:
【請求項5】 前記発泡剤が、酸化鉄と、炭化珪素また
は炭材のうち少なくとも1種とからなることを特徴とす
る請求項1〜4のいずれか1項記載の人工軽量骨材の製
造方法。
5. The production of an artificial lightweight aggregate according to claim 1, wherein the foaming agent comprises iron oxide and at least one of silicon carbide and carbonaceous material. Method.
【請求項6】 請求項1〜5のいずれか1項記載の製造
方法により得られ、かつ絶乾比重が0.5〜1.5、一
軸圧縮破壊荷重が50kgf以上で、吸水率が15%以
下であることを特徴とする人工軽量骨材。
6. A method according to claim 1, wherein the absolute specific gravity is 0.5 to 1.5, the uniaxial compressive breaking load is 50 kgf or more, and the water absorption is 15%. An artificial lightweight aggregate characterized by the following.
JP9505499A 1999-04-01 1999-04-01 Production of artificial lightweight aggregate and artificial lightweight aggregate obtained by the method Pending JP2000290050A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
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Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP9505499A JP2000290050A (en) 1999-04-01 1999-04-01 Production of artificial lightweight aggregate and artificial lightweight aggregate obtained by the method

Publications (1)

Publication Number Publication Date
JP2000290050A true JP2000290050A (en) 2000-10-17

Family

ID=14127346

Family Applications (1)

Application Number Title Priority Date Filing Date
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Country Link
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015209317A (en) * 2014-04-28 2015-11-24 住友重機械工業株式会社 Conveyance system of coal ash generated in coal burning boiler and conveyance method of coal ash generated in coal burning boiler
JP2019048735A (en) * 2017-09-08 2019-03-28 太平洋セメント株式会社 Production method of fine aggregate
JP2019051511A (en) * 2018-11-07 2019-04-04 住友重機械工業株式会社 Conveyance system of coal ash generated in coal burning boiler and conveyance method of coal ash generated in coal burning boiler

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015209317A (en) * 2014-04-28 2015-11-24 住友重機械工業株式会社 Conveyance system of coal ash generated in coal burning boiler and conveyance method of coal ash generated in coal burning boiler
JP2019048735A (en) * 2017-09-08 2019-03-28 太平洋セメント株式会社 Production method of fine aggregate
JP2019051511A (en) * 2018-11-07 2019-04-04 住友重機械工業株式会社 Conveyance system of coal ash generated in coal burning boiler and conveyance method of coal ash generated in coal burning boiler

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