JP2010222212A

JP2010222212A - Method for producing super-lightweight material

Info

Publication number: JP2010222212A
Application number: JP2009073398A
Authority: JP
Inventors: Kazufumi Nakamura; 和史中村; Nobuhiko Abe; 信彦阿部; Toshio Imai; 敏夫今井; Hiroshi Ozu; 博小津
Original assignee: Taiheiyo Cement Corp
Current assignee: Taiheiyo Cement Corp
Priority date: 2009-03-25
Filing date: 2009-03-25
Publication date: 2010-10-07

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for stably producing a super-lightweight material having specific gravity in oven-dried state of ≤1.0 g/cm<SP>3</SP>at a low cost. <P>SOLUTION: The method for producing a super-lightweight material includes a firing process for firing granules of an expansible raw material or expanded shale by a rotary kiln while adding a fusion preventing agent to the granules or the like, in which fine particles recovered from an exhaust gas of the rotary kiln and containing the fusion preventing agent is returned to the firing process. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

本発明は、土木、建築に使用される超軽量材の製造方法に関する。 The present invention relates to a method for manufacturing an ultralight material used for civil engineering and construction.

絶乾比重が１．０ｇ／ｃｍ³以下である超軽量骨材等の超軽量材の焼成温度は、絶乾比重が１．２〜１．３ｇ／ｃｍ³である通常の軽量材と比べて高くなる傾向にある。そして焼成温度が高い結果、焼成中に超軽量材の原料の粒子間または当該粒子と炉壁の間で融着が生じ易くなり、焼成運転を安定的に行うことが困難になるという問題があった。
当該問題の解決手段として、従来から原料よりも融点の高い無機粉末を融着防止材としてロータリーキルン等の焼成炉内に投入し、前記融着を防止することが行われてきた。 The firing temperature of an ultralight material such as an ultralight aggregate having an absolute dry specific gravity of 1.0 g / cm ³ or less is higher than that of a normal light material having an absolute dry specific gravity of 1.2 to 1.3 g / cm ^3. It tends to be higher. As a result of the high firing temperature, fusion is likely to occur between the particles of the raw material of the ultralight material during firing or between the particles and the furnace wall, making it difficult to stably perform the firing operation. It was.
As a means for solving this problem, conventionally, an inorganic powder having a melting point higher than that of the raw material has been introduced into a firing kiln such as a rotary kiln as an anti-fusion material to prevent the fusion.

例えば、特許文献１には、粉末状の原料を一定形状に成形した塊状原料を、ロータリーキルンに供給して焼成発泡させるに当り、このロータリーキルンのキルン主体を予め原料供給側から順次、小径部、傾斜段部、大径部に構成して、小径部で予熱するとともに、この小径部で融着を助長する原料中の粉化物の除去ならびに融着防止剤の添加を行い、次いで大径部で高温により膨張発泡させて超軽量骨材を製造する方法が開示されている。しかし、この方法によれば原料中の微粉化物は除去できるとしても、キルンの転動に伴う発塵・飛散により融着防止剤の多くはキルン外に排出されるため、融着防止剤が不足する虞がある。
また、特許文献２には、水溶性結合剤を使用した造粒物を焼成し、膨張粒子とする際に、乾燥状態で造粒物に融着防止材を転動によりコーティングし、該コーティングに使用した融着防止材量の等量以下の融着防止材と共に焼成する膨張粒子の製造方法が開示されている。当該方法では、初めに原料の造粒物に融着防止材をコーティングして均一な被覆を形成し、次に焼成時の造粒物表面の膨張により新たに生じた被覆されていない表面に対しては、コーティング原料と同時に投入する融着防止材により再度被覆するものである。しかし、この方法では新たにコーティング工程が必要となってコストアップにつながり、また、キルンの転動に伴う発塵・飛散により融着防止材の多くはキルン外に排出されるため、融着防止材が過剰に必要となる。
また、特許文献３には、ロータリーキルン内の焼点部に、シリカ又はアルミナ含有量が９０％以上であり且つ平均粒径が５〜６０μｍである融着防止材を供給しながら骨材原料を焼成する人工骨材の製造方法と、当該融着防止材の供給量が、骨材原料に対し外割で５〜１００質量％である人工骨材の製造方法が開示されている。しかし、この方法では融着防止材の供給量が原料量に対して５〜１００重量％と多量の融着防止材を必要としていることから、特許文献３に記載の製造方法では、発塵・飛散による融着防止材のロスは極めて大きい。 For example, in Patent Document 1, when a bulk raw material obtained by molding a powdery raw material into a fixed shape is supplied to a rotary kiln and fired and foamed, the kiln main body of this rotary kiln is sequentially preliminarily from the raw material supply side in order of a small diameter portion, an inclined Constructed into a stepped part and a large diameter part, preheated at the small diameter part, removed the pulverized material in the raw material that promotes fusion at this small diameter part and added an anti-fusing agent, then heated at the large diameter part Discloses a method for producing an ultralight aggregate by expansion and foaming. However, even if fine powder in the raw material can be removed by this method, most of the anti-fusing agent is discharged outside the kiln due to dust generation and scattering accompanying the rolling of the kiln, so the anti-fusing agent is insufficient. There is a risk of doing.
Further, in Patent Document 2, when a granulated product using a water-soluble binder is baked to obtain expanded particles, the granulated product is coated by rolling on the granulated product in a dry state. A method for producing expanded particles that is fired together with an anti-fusing material equal to or less than the amount of the anti-fusing material used is disclosed. In this method, the raw granule is first coated with an anti-fusing material to form a uniform coating, and then the uncoated surface newly generated by the expansion of the granulated surface during firing is applied. In this case, the coating material is coated again with an anti-fusing material that is added simultaneously with the coating material. However, this method necessitates a new coating process, which leads to an increase in cost, and because most of the anti-fusing material is discharged outside the kiln due to dust generation and scattering associated with the rolling of the kiln, preventing fusion. Excessive material is required.
Further, in Patent Document 3, an aggregate raw material is fired while supplying an anti-fusing material having a silica or alumina content of 90% or more and an average particle size of 5 to 60 μm to a burning point in a rotary kiln. And an artificial aggregate manufacturing method in which the supply amount of the anti-fusing material is 5 to 100% by mass with respect to the aggregate raw material. However, in this method, since the supply amount of the anti-fusing material requires 5 to 100% by weight relative to the amount of the raw material, a large amount of anti-fusing material is required. The loss of the anti-fusing material due to scattering is extremely large.

特公平６−７２０３５号公報Japanese Patent Publication No. 6-72035 特開２００３−２７１０号公報JP 2003-2710 A 特開２００３−９５７１６公報JP 2003-95716 A

従って、本発明は、絶乾比重１．０ｇ／ｃｍ³以下の超軽量材を安定的かつ安価に製造できる方法を提供することを目的とする。 Accordingly, an object of the present invention is to provide a method capable of stably and inexpensively producing an ultralight material having an absolute dry specific gravity of 1.0 g / cm ³ or less.

本発明者らは、前記課題に鑑み鋭意研究したところ、融着防止材の使用量を低減できるとともに超軽量材を安定的かつ安価に製造できる方法を見出し本発明を完成した。 As a result of intensive research in view of the above problems, the present inventors have found a method capable of reducing the amount of anti-fusing material used and producing an ultralight material stably and inexpensively, thereby completing the present invention.

すなわち、本発明は、膨張性原料の造粒物または膨張頁岩に融着防止材を添加しつつ、ロータリーキルンにより焼成する焼成工程において、ロータリーキルンの排ガスから回収された融着防止材を含む細粒分を、前記焼成工程に戻す超軽量材の製造方法である。 That is, the present invention provides a fine-grain fraction containing an anti-fusing material recovered from exhaust gas of a rotary kiln in a firing step of baking with a rotary kiln while adding an anti-fusing material to an expanded raw material granulated product or expanded shale. Is a method for producing an ultralight material that is returned to the firing step.

本発明の超軽量材の製造方法によれば、融着防止材の使用量を低減できるとともに超軽量材を安定的かつ安価に製造することができる。 According to the method for manufacturing an ultralight material of the present invention, it is possible to reduce the amount of the anti-fusing material used and to manufacture the ultralight material stably and inexpensively.

本発明の超軽量材の製造方法を実施するための製造装置の一例を示す図である。It is a figure which shows an example of the manufacturing apparatus for enforcing the manufacturing method of the super lightweight material of this invention.

以下、本発明の超軽量材の製造方法について説明する。
本発明に使用する膨張性原料は、膨張頁岩、真珠岩、黒曜石、粘土、粘板岩、石炭灰および汚泥等が挙げられる。
また、前記膨張性原料に水やバインダー等の成形助剤を加えて混練した後、ペレタイザーまたは押し出し成形機等により所要の形状に成形する。当該形状としては、球状、ペレット状または円柱状等でよく、その寸法は２〜２０ｍｍ程度が好適である。なお、珪質頁岩、真珠岩および黒曜石は、比較的強度が高いため必ずしも成形することを要しない。 Hereinafter, the manufacturing method of the super lightweight material of this invention is demonstrated.
Examples of the expandable raw material used in the present invention include expanded shale, nacre, obsidian, clay, slate, coal ash, and sludge.
Further, after adding a molding aid such as water or a binder to the expandable raw material and kneading, it is molded into a required shape by a pelletizer or an extrusion molding machine. The shape may be a spherical shape, a pellet shape, a cylindrical shape, or the like, and the size is preferably about 2 to 20 mm. Note that siliceous shale, pearlite, and obsidian do not necessarily need to be molded because of their relatively high strength.

本発明に使用する融着防止材は、原料の融着を有効に防止するために原料よりも融点が高いことが要求されるので、シリカまたはアルミナを主成分とする材がよく、珪石粉、アルミナ粉等が例示できる。また、融着防止材の平均粒径は５〜６０μｍが好ましい。融着防止材の平均粒径が５μｍ未満では、ロータリーキルンの炉壁に付着しやすく融着防止材のロスが大きくなり、また融着防止材の平均粒径が６０μｍを超えると、融着防止材が原料表面を均質に覆うことが困難になる場合がある。
融着防止材の添加量は、原料に対し外割で２〜１０質量％が好ましい。融着防止材の添加量が２質量％未満では、融着防止効果が十分でなく、融着防止材の添加量が１０質量％を超えても融着防止効果は飽和して寧ろコスト高になる。 Since the anti-fusing material used in the present invention is required to have a melting point higher than that of the raw material in order to effectively prevent the fusion of the raw material, a material mainly composed of silica or alumina is preferable. Alumina powder etc. can be illustrated. The average particle size of the anti-fusing material is preferably 5 to 60 μm. If the average particle size of the anti-fusing material is less than 5 μm, it tends to adhere to the furnace wall of the rotary kiln and the loss of the anti-fusing material increases, and if the average particle size of the anti-fusing material exceeds 60 μm, the anti-fusing material May be difficult to cover the surface of the raw material uniformly.
The addition amount of the anti-fusing material is preferably 2 to 10% by mass with respect to the raw material. If the addition amount of the anti-fusing material is less than 2% by mass, the anti-fusing effect is not sufficient, and even if the addition amount of the anti-fusing material exceeds 10% by mass, the anti-fusing effect is saturated and rather expensive. Become.

次に、本発明の製造方法の一形態を図１の製造装置を用いて説明する。
初めに、原料タンク１から原料を、融着防止材タンク２から融着防止材を、所定の配合割合になるようにそれぞれ好適な速度で、下部に設置したベルトコンベア３上に投下する。原料と融着防止材の混合物はベルトコンベア３により運ばれ、投入管４内を通ってロータリーキルン５の窯尻部６に投入される。なお、原料と融着防止材の混合を事前に十分に行うために、投入管４の入口部から出口部までのいずれかの位置に混合装置を設置してもよい。
原料と融着防止材の混合物は、ロータリーキルン５内を転動・混合しながらバーナー７から供給された燃料の燃焼熱により焼成され、窯前部８に到達するまでに原料の膨張は概ね終了し、超軽量材が得られる。
製造された超軽量材はクーラー９において冷却されて製造装置外に排出される。
ここで、融着防止材は、前記の投入管４を通じてロータリーキルン５内に投入する態様のほかに、投入管１０を通じてロータリーキルン５内に投入する態様でもよい。両態様のいずれか一つまたは両態様を同時に実施することができる。投入管１０を通じて融着防止材をロータリーキルン５内に投入する場合は、その投入位置は焼点付近が好ましい。 Next, an embodiment of the manufacturing method of the present invention will be described using the manufacturing apparatus of FIG.
First, the raw material from the raw material tank 1 and the anti-fusing material from the anti-fusing material tank 2 are dropped onto the belt conveyor 3 installed in the lower part at a suitable speed so as to have a predetermined blending ratio. The mixture of the raw material and the anti-fusing material is conveyed by the belt conveyor 3, passed through the charging pipe 4, and charged into the kiln bottom 6 of the rotary kiln 5. In order to sufficiently mix the raw material and the anti-fusing material in advance, a mixing device may be installed at any position from the inlet portion to the outlet portion of the charging pipe 4.
The mixture of the raw material and the anti-fusing material is baked by the combustion heat of the fuel supplied from the burner 7 while rolling and mixing in the rotary kiln 5, and the expansion of the raw material is almost completed before reaching the kiln front part 8. An ultralight material is obtained.
The manufactured ultralight material is cooled in the cooler 9 and discharged out of the manufacturing apparatus.
Here, the fusion preventing material may be charged into the rotary kiln 5 through the charging tube 10 in addition to the mode of charging into the rotary kiln 5 through the charging tube 4. Either one or both embodiments can be performed simultaneously. When the anti-fusing material is charged into the rotary kiln 5 through the charging tube 10, the charging position is preferably near the burning point.

原料と融着防止材の混合物はロータリーキルン５内を転動する間に、その粉粒体が発塵・飛散しロータリーキルン５内のガス流に乗ってキルン排ガスの一部となる。
前記粉粒体を含むキルン排ガスはロータリーキルン５を通過した後、サイクロン１１に至る。当該粉粒体中の、粒径が５μｍ以上の細粒分は、サイクロン１１によりキルン排ガスから分離・回収される。回収された細粒分は、融着防止材を７５〜９０質量％と多量に含むため十分な融着防止効果を有する。
従って、当該回収された細粒分は、回収細粒分投入管１２および／または投入管１０を通じてロータリーキルン５内に戻すことにより、融着防止材の一部として再利用される。ここで細粒分を戻す位置は、回収細粒分投入管１２を通じて戻す場合は、窯尻部を起点にしてロータリーキルン長さの約１／３の地点が好ましく、また、投入管１０を通じて戻す場合は焼点付近が好ましい。 While the mixture of the raw material and the anti-fusing material rolls in the rotary kiln 5, the particulates generate dust and scatter and ride on the gas flow in the rotary kiln 5 to become a part of the kiln exhaust gas.
The kiln exhaust gas containing the granular material reaches the cyclone 11 after passing through the rotary kiln 5. The fine particles having a particle diameter of 5 μm or more in the powder are separated and collected from the kiln exhaust gas by the cyclone 11. The recovered fine particles have a sufficient anti-fusing effect because they contain a large amount of anti-fusing material as 75 to 90% by mass.
Therefore, the recovered fine particles are reused as a part of the anti-fusing material by returning them to the rotary kiln 5 through the recovered fine particle input pipe 12 and / or the input pipe 10. Here, the position for returning the fine particles is preferably about 1/3 of the rotary kiln length starting from the bottom of the kiln when returning through the recovered fine particle input pipe 12, and when returning through the input pipe 10 Is preferably near the burning point.

次に、前記細粒分が除去された粉粒体を含むキルン排ガスは、電気集塵機１３に至る。当該粉粒体中の、粒径が５μｍ未満の微粒分は、電気集塵機１３によりキルン排ガスから分離・回収される。回収された微粒分は、融着防止材を５〜２０質量％と少量しか含まないため融着防止効果は低く、ロータリーキルン５内には戻されない。
最後に、微粒分が除去されたキルン排ガスは、煙突１４を通じて外部に排出される。 Next, the kiln exhaust gas containing the granular material from which the fine particles have been removed reaches the electrostatic precipitator 13. Fine particles having a particle size of less than 5 μm in the powder are separated and collected from the kiln exhaust gas by the electric dust collector 13. The recovered fine particles contain only 5 to 20% by mass of the anti-fusing material, so that the anti-fusing effect is low and is not returned to the rotary kiln 5.
Finally, the kiln exhaust gas from which the fine particles have been removed is discharged to the outside through the chimney 14.

以下、本発明を実施例により説明するが、本発明は実施例に限定されるものではない。
［使用材料］
１．原料
膨張頁岩：淡路島内田鉱山産の珪質頁岩
汚泥造粒物：建設汚泥１００重量部に対し、水を２０重量部を加えて混合し、パンペレタイザーを用いて粒径が５〜２０ｍｍの汚泥造粒物を調製した。
２．融着防止材
珪石粉：宇部サンド工業社製平均粒径４０μｍ
アルミナ粉：日本軽金属社製平均粒径５０μｍ EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to an Example.
[Materials used]
1. Raw material expanded shale: Silica shale sludge granulated material from Uchida mine, Awajishima: Mix 100 parts by weight of construction sludge with 20 parts by weight of water and mix with sludge having a particle size of 5 to 20 mm using a pan pelletizer Granules were prepared.
2. Anti-fusing material Silica stone powder: Ube Sand Industry Co., Ltd. average particle size 40μm
Alumina powder: Nippon Light Metal Co., Ltd. average particle size 50μm

［試験方法］
表１に示す原料をベルトコンベア３上に投下して、内径４５０ｍｍ×長さ８５００ｍｍのロータリーキルン５内に原料を１００ｋｇ／ｈの割合で投入するとともに、表１に示す添加量の融着防止材を投入管４または投入管１０を通じて、ロータリーキルン５内に投入し、表１に示す温度で焼成して超軽量材を得た。
また、回収細粒分を再利用する場合は、回収細粒分投入管１２または投入管１０を通じてロータリーキルン５内に戻した。なお、回収細粒分投入管１２は窯尻部から約３ｍの、ロータリーキルン５の上部に設置した。
得られた超軽量材の絶乾密度および運転状況を表２に示した。 [Test method]
The raw materials shown in Table 1 are dropped on the belt conveyor 3, and the raw materials are introduced into the rotary kiln 5 having an inner diameter of 450 mm and a length of 8500 mm at a rate of 100 kg / h. An ultralight material was obtained by charging the rotary kiln 5 through the input tube 4 or the input tube 10 and firing at the temperature shown in Table 1.
When the recovered fine particles are reused, they are returned to the rotary kiln 5 through the recovered fine particle input pipe 12 or the input pipe 10. In addition, the collection | recovery fine particle injection pipe | tube 12 was installed in the upper part of the rotary kiln 5 about 3 m from the kiln bottom part.
Table 2 shows the absolute dry density and operating conditions of the obtained ultralight material.

表２から分かるように、回収細粒分を再利用した実施例１〜３では、安定して製造装置を運転することができ、絶乾密度が０．８５ｇ／ｃｍ³以下の良質の超軽量材が得られた。一方、回収細粒分を再利用しない比較例１〜３では原料の融着が生じ、比較例１ではこの融着により運転を中止せざるを得なかった。 As can be seen from Table 2, in Examples 1 to 3 in which the recovered fine particles are reused, the production apparatus can be operated stably, and a super-light weight of high quality with an absolute dry density of 0.85 g / cm ³ or less. A material was obtained. On the other hand, in Comparative Examples 1 to 3 in which the recovered fine particles were not reused, the raw material was fused, and in Comparative Example 1, the operation had to be stopped by this fusion.

１原料タンク
２、１５融着防止材タンク
３ベルトコンベア
４、１０投入管
５ロータリーキルン
６窯尻部
７バーナー
８窯前部
９クーラー
１１サイクロン
１２回収細粒分投入管
１３電気集塵機
１４煙突 DESCRIPTION OF SYMBOLS 1 Raw material tank 2, 15 Anti-fusing material tank 3 Belt conveyor 4, 10 Input pipe 5 Rotary kiln 6 Kiln bottom part 7 Burner 8 Kiln front part 9 Cooler 11 Cyclone 12 Collection fine particle input pipe 13 Electric dust collector 14 Chimney

Claims

In the firing step of firing with a rotary kiln while adding an anti-fusing material to the granulated material or expanded shale of the expandable raw material, fine particles containing the anti-fusing material recovered from the exhaust gas of the rotary kiln are added to the firing step. A method for producing an ultralight material characterized by being returned.