JPH0338226B2 - - Google Patents
Info
- Publication number
- JPH0338226B2 JPH0338226B2 JP57006347A JP634782A JPH0338226B2 JP H0338226 B2 JPH0338226 B2 JP H0338226B2 JP 57006347 A JP57006347 A JP 57006347A JP 634782 A JP634782 A JP 634782A JP H0338226 B2 JPH0338226 B2 JP H0338226B2
- Authority
- JP
- Japan
- Prior art keywords
- calcium silicate
- aqueous slurry
- weight
- molded body
- added
- 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.)
- Expired - Lifetime
Links
- 239000000378 calcium silicate Substances 0.000 claims description 29
- 229910052918 calcium silicate Inorganic materials 0.000 claims description 29
- OYACROKNLOSFPA-UHFFFAOYSA-N calcium;dioxido(oxo)silane Chemical compound [Ca+2].[O-][Si]([O-])=O OYACROKNLOSFPA-UHFFFAOYSA-N 0.000 claims description 29
- 239000002002 slurry Substances 0.000 claims description 26
- MKTRXTLKNXLULX-UHFFFAOYSA-P pentacalcium;dioxido(oxo)silane;hydron;tetrahydrate Chemical group [H+].[H+].O.O.O.O.[Ca+2].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[O-][Si]([O-])=O.[O-][Si]([O-])=O.[O-][Si]([O-])=O.[O-][Si]([O-])=O.[O-][Si]([O-])=O.[O-][Si]([O-])=O MKTRXTLKNXLULX-UHFFFAOYSA-P 0.000 claims description 20
- 239000002994 raw material Substances 0.000 claims description 18
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 16
- 238000000465 moulding Methods 0.000 claims description 12
- 238000004519 manufacturing process Methods 0.000 claims description 9
- 238000004062 sedimentation Methods 0.000 claims description 9
- 238000010438 heat treatment Methods 0.000 claims description 6
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 32
- 239000000292 calcium oxide Substances 0.000 description 18
- 239000000047 product Substances 0.000 description 18
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 15
- 235000012255 calcium oxide Nutrition 0.000 description 14
- 239000013078 crystal Substances 0.000 description 13
- UGGQKDBXXFIWJD-UHFFFAOYSA-N calcium;dihydroxy(oxo)silane;hydrate Chemical compound O.[Ca].O[Si](O)=O UGGQKDBXXFIWJD-UHFFFAOYSA-N 0.000 description 11
- 239000010456 wollastonite Substances 0.000 description 11
- 229910052882 wollastonite Inorganic materials 0.000 description 11
- 229910004298 SiO 2 Inorganic materials 0.000 description 10
- 238000006243 chemical reaction Methods 0.000 description 10
- 238000005452 bending Methods 0.000 description 9
- 239000007787 solid Substances 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 7
- 239000000377 silicon dioxide Substances 0.000 description 7
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 6
- 238000000034 method Methods 0.000 description 6
- 239000006227 byproduct Substances 0.000 description 4
- 150000001875 compounds Chemical class 0.000 description 4
- 238000007796 conventional method Methods 0.000 description 4
- 230000018044 dehydration Effects 0.000 description 4
- 238000006297 dehydration reaction Methods 0.000 description 4
- 239000003365 glass fiber Substances 0.000 description 4
- 230000035484 reaction time Effects 0.000 description 4
- 239000003513 alkali Substances 0.000 description 3
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 3
- 239000004568 cement Substances 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 230000005484 gravity Effects 0.000 description 3
- 239000011810 insulating material Substances 0.000 description 3
- 239000012212 insulator Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 229930014626 natural product Natural products 0.000 description 3
- 239000004575 stone Substances 0.000 description 3
- 239000000725 suspension Substances 0.000 description 3
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 2
- 235000011941 Tilia x europaea Nutrition 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 239000010440 gypsum Substances 0.000 description 2
- 229910052602 gypsum Inorganic materials 0.000 description 2
- 239000004571 lime Substances 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 239000012783 reinforcing fiber Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- 230000004580 weight loss Effects 0.000 description 2
- 239000005909 Kieselgur Substances 0.000 description 1
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 description 1
- 239000010425 asbestos Substances 0.000 description 1
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 235000011116 calcium hydroxide Nutrition 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- LRCFXGAMWKDGLA-UHFFFAOYSA-N dioxosilane;hydrate Chemical compound O.O=[Si]=O LRCFXGAMWKDGLA-UHFFFAOYSA-N 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005868 electrolysis reaction Methods 0.000 description 1
- 239000012774 insulation material Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000011490 mineral wool Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910052895 riebeckite Inorganic materials 0.000 description 1
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- -1 tobermorite group compound Chemical class 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
- C04B28/18—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing mixtures of the silica-lime type
- C04B28/186—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing mixtures of the silica-lime type containing formed Ca-silicates before the final hardening step
- C04B28/188—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing mixtures of the silica-lime type containing formed Ca-silicates before the final hardening step the Ca-silicates being present in the starting mixture
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
Description
本発明は珪酸カルシウム成形体の製造方法に関
するものである。詳しくは、低嵩密度で耐熱性、
機械的強度及び寸法安定性の優れた、従つて、保
温材、断熱材として好適な珪酸カルシウム成形体
の製造方法に関するものである。
珪酸カルシウム成形体、とくにゾノトライトを
主成分とするものは1000℃以上の耐熱性を有する
ため保温材、断熱材として好適である。一般に、
保温材、断熱材に用いられる珪酸カルシウム成形
体は熱伝導率の低いものが要求されると共に機械
的強度の大きいものが要求される。しかしなが
ら、熱伝導率を低くするためには嵩密度の低い成
形体を製造することが必要であるが、嵩密度が低
下すると強度も低下するので嵩密度が低く、機械
的強度も大きい成形体を製造することは極めて困
難である。
本発明者らの一部は、このような成形体を製造
する方法として特定の珪酸カルシウム水和物を含
む水性スラリーを脱水成形した後、水蒸気養生す
ることにより珪酸カルシウム成形体を製造する方
法が有効であることを見出し先に提案した。（特
願昭52−63621）（特公昭58−30259号公報）
この方法は極めて有利な方法があるが、脱水成
形時の珪酸カルシウム水和物が非常に嵩高いため
成形圧が高くなりそのため、成形作業に時間がか
かる。又、成形圧の方向に成形体が収縮するとい
う更に改善すべき点があつた。
この点に鑑み本発明者らは鋭意研究した結果、
特定の珪酸カルシウム水和物から実質的に構成さ
れるスラリーにワラストナイトを添加し成形した
後、水蒸気養生すれば、成形性が良好であり、従
来の方法により得られる珪酸カルシウム成形体に
比し同嵩比重であればより高い曲げ強度を有し、
同程度の曲げ強度であればより低い嵩比重を有す
る珪酸カルシウム成形体が得られることを見出し
本発明に到達した。
すなわち、本発明の要旨とするところは、水中
に分散させた石灰質原料と珪酸質原料とを加熱下
反応させて得られる沈降体積が15cm3／ｇ以上のト
バモライトグループの化合物からなる珪酸カルシ
ウム水和物から実質的に構成される水性スラリー
を脱水成形した後、水蒸気養生することにより珪
酸カルシウム成形体を製造する方法において、該
水性スラリーに、ワラストナイトを成形体中に５
〜60重量％含有するように添加することを特徴と
する珪酸カルシウム成形体の製造方法に存する。
以下、本発明を詳細に説明するに、本発明方法
において珪酸質原料としては珪藻土、珪石等の天
然品あるいは、シリコンダスト、湿式燐酸製造プ
ロセスで副生する珪弗化水素酸と水酸化アルミニ
ウムとを反応させて得られるシリカ（以下単に湿
式燐酸副生シリカという）等の工業副産物が用い
られる。また、石灰質原料としては生石灰、消石
灰、カーバイド滓等の周知のものがいずれも使用
できるが、生石灰がとくに好適である。
珪酸質原料と石灰質原料の配合モル比（CaO／
SiO2）は、最終成形品中の珪酸カルシウム水和
物の結晶としてゾノトライトを所望する場合、普
通0.8〜1.2の範囲内であり、結晶性トバモライト
を所望する場合、普通0.7〜1.0の範囲内である。
前記両原料を分散させる水の量は、原料固形分
に対し15重量倍以上であればよく、とくに17〜40
重量倍の範囲が好ましい。
勿論両原料を分散させるのに石灰質原料含有ス
ラリー中の水では不十分なときは更に水を加えて
もよい。
水中に分散させた前記両原料を加熱下反応させ
れば珪酸カルシウム水和物結晶を含む水性スラリ
ーが得られる。
水性スラリー中の珪酸カルシウム水和物結晶の
沈降体積は15cm3／ｇ以上、好ましくは、15〜30
cm3／ｇであることが必要である。沈降体積が15
cm3／ｇより低い場合には高強度の成形体は得られ
ない。
ここで沈降体積とは次式（）によつて算出さ
れる値である。
沈降体積＝Ｖ／Ｗ ……（）
式（）においてＷは原料固形分（例えば生石
灰＋珪酸質原料）の総重量（生石灰以外の石灰質
原料を用いる場合には生石灰に換算して総重量を
求める。）であり、Ｖは反応後得られたスラリー
を24時間静置後に沈降した固形分が占める体積で
ある。実際には通常次のようにして求める。まず
反応後得られた総重量W0ｇのスラリーからW1ｇ
をメスシリンダーに採取し、これを24時間静置
し、沈降した固形分が占める体積V1cm3を測定し、
次式（）より算出する。
沈降体積＝V1／W1×Ｗ／W0 ……（）
なお、Ｗは式（）と同義で原料の総重量を示
す。
沈降体積を15cm3／ｇ以上にする方法としては、
反応を撹拌下、130℃以上、とくに150〜230℃、
最適には160〜210℃で実施する方法が挙げられ
る。その際、反応系は液状に保持する必要があ
り、従つて反応は加圧下で実施される。
更に該スラリーは、実質的にトバモライトグル
ープの化合物からなる珪酸カルシウム水和物で構
成されていることが必要である。
珪酸カルシウム水和物結晶は種々知られてお
り、一般にテーラー（H.F.W.Taylor）著「ザケ
ミストリーオブセメント（The Chemistry of
Cements）」第１巻第182頁表に示す分類に従つ
て整理される。トバモライトグループの化合物に
はトバモライトゲル、Ｃ−Ｓ−Ｈ（）、Ｃ−Ｓ−
Ｈ（）及び結晶性トバモライトが含まれるが、
そのいずれであつてもよい。珪酸カルシウム水和
物結晶は、トバモライトゲル→Ｃ−Ｓ−Ｈ（）
→Ｃ−Ｓ−Ｈ（）→11Åトバモライト（結晶性
トバモライト）→ゾノトライトの順で普通転移す
るので、所望の結晶を得るには反応温度、時間を
調節するだけで充分である。すなわち、反応温度
を高くすれば、あるいは反応時間を長くすれば、
結晶は矢（→）印の方向に転移する。第１の条件
を達成するための温度範囲で反応を実施すれば、
通常トバモライトグループの化合物が得られる。
しかし、反応温度がとくに高かつたり反応時間が
とくに長いとゾノトライトが得られるので、その
場合は温度を下げるか、反応時間を短縮すればよ
い。なお、最終成形品中の結晶として結晶性トバ
モライトを所望する場合には、スラリー中の珪酸
カルシウム水和物はトバモライトゲル、Ｃ−Ｓ−
Ｈ（）またはＣ−Ｓ−Ｈ（）であることが必要
である。
本発明においては、上記水性スラリーにワラス
トナイトを添加する。ここでいうワラストナイト
とは「石膏石灰ハンドブツク」石膏石灰学会編
271頁〜275頁に説明されているものの総称であり
以下のように分類できる。
即ち、ワラストナイト（化学式CaO・SiO2）
は低温型（β−CaO・SiO2）と高温型（α−
CaO・SiO2）の２種類に分類される。低温型は
約1125℃以上で高温型にかわる。低温型には天然
品とゾノトライトなどを加熱脱水して得られる合
成品があり、高温型は主に合成品である。
本発明は使用するワラストナイトは、上記いず
れのタイプでもよいが、特に繊維状結晶の著しい
低温型の天然品が好ましい。またワラストナイト
の添加量は最終的に得られる成形体中に５〜60重
量％、好ましくは、10〜50重量％、特に好ましく
は、10〜35重量％含有するように使用するのが好
ましく、10重量％以下では成形性の面で十分な効
果が得られず、また50重量％以上では成形体の軽
量化を阻害するとともに、マトリツクスを形成す
る珪酸カルシウム水和物の量が相対的に減少する
ため、成形体の機械的強度が低下し好ましくな
い。
本発明においては、通常、上記水性スラリーに
補強繊維を添加する。補強繊維としては周知の
種々のものがいずれも使用でき、例えば石綿、岩
綿、ガラス繊維等が使用される。普通、最終成形
品中に0.5〜10重量％含有するように添加される。
かくして得られる上記水性スラリーは常法に従
つて加圧脱水成形される。その際の圧力は通常１
〜200Kg／cm2Ｇの範囲であり、成形体の嵩比重の
調整は加圧成形機のピストンストロークの調整に
より行なわれる。
次いで得られた成形体を常法に従つて加圧下で
水蒸気養生いわゆるオートクレーブ養生する。こ
の水蒸気養生により成形体の結晶を、トバモライ
トゲル、Ｃ−Ｓ−Ｈ（）またはＣ−Ｓ−Ｈ（）
の場合は結晶性トバモライトまたはゾノトライト
に、結晶性トバモライトの場合はゾノトライトに
転移させることが必要である。この水蒸気養生に
よる結晶の転移により嵩密度が低く機械的強度の
優れた成形体を得ることができる。水蒸気圧は一
般に高い程反応時間を短縮できるが、通常は５〜
50Kg／cm2Ｇの範囲である。最終成形品の結晶とし
てゾノトライトを所望する場合には12〜40Kg／cm2
Ｇ、結晶性トバモライトを所望する場合には６〜
30Kg／cm2Ｇ水蒸気が好適である。このような条件
において前記した転移は普通容易に行なわれる。
転移が所望するように行なわれない場合、このよ
うな場合は極めて稀であるが、例えばゾノトライ
トを所望するのに結晶性トバモライトが得られる
場合は水蒸気圧を上げるか水蒸気養生の時間を延
長すればよいし、また結晶性トバモライトを所望
するのにゾノトライトが得られる場合は逆に水蒸
気圧を下げるか水蒸気養生の時間を短縮すればよ
い。
高耐熱性の要求される用途においてはゾノトラ
イトに転移させることが好ましい。
以上本発明について詳細に説明したが、本発明
方法によれば嵩密度0.15ｇ／cm2程度のもので曲げ
強度が10Kg／cm2以上、0.20ｇ／cm2程度のもので15
Kg／cm2以上と常法で得られる成形体に比べ同嵩密
度で約２倍以上の高い曲げ強度を有する珪酸カル
シウム成形体を成形圧、成形速度の面から成形性
が秀れ、寸法安定性よく得ることができる。
しかも得られる成形体は、耐熱性のあるワラス
トナイトとマトリツクスである珪酸カルシウム水
和物結晶がからみ合つて秀れた耐熱性を有してい
るので、一般の保温材、断熱材の他加熱炉、乾燥
炉、ダクト、アルミニウム工業における各種工業
用耐火断熱材として広範囲な用途が期待できる。
次に本発明を実施例により更に具体的に説明す
るが、本発明はその要旨をこえない限り以下の実
施例に限定されるものではない。
なお、実施例中「部」及び「％」とあるは夫夫
「重量部」「重量％」を示す。
実施例１〜５及び比較例１〜３
生石灰（96.2％ CaO）49.6部に温水を加えて
消化し、これに珪石（96.4％ SiO2）50.4部を添
加した後、総水量が固形分に対し27.5部になるよ
うに水を加えた。このようにして得られた懸濁液
をオートクレーブ中で15Kg／cm2Ｇ 200℃の条件
下で2.0時間撹拌し反応させたところ、沈降体積
21ｇ／cm2のCSHを含む水性スラリーが得られた。
この水性スラリーに耐アルカリガラス繊維３部及
びワラストナイトを表１に示す種類と量添加し
（比較例３はアルミナを添加）嵩密度が0.20（実施
例４のみは0.15）になるようにスラリーを調整
し、300×300×50mm（縦×横×厚さ）の寸法に10
Kg／cm2の圧力にて加圧脱水成形した。次いで得ら
れた成形体とオートクレーブに仕込み、水蒸気11
Kg／cm2Ｇ 187℃の条件で５時間水蒸気養生した
後、150℃で８時間乾燥した。表１にプレス時間、
乾燥後の板厚収縮率、嵩密度、曲げ強度及び1000
℃３時間加熱後の残存収縮率と重量減少％を示し
た。
比較例 ４〜５
生石灰（96.2％ CaO）46.7部に温水を加えて
消化し、これにシリカ（湿式燐酸副生シリカ
SiO2 97.8％）49.2部を添加した後、総水量が固
形分に対し10重量倍になるように水を加えた。こ
のようにして得られた懸濁液を90℃で２時間撹拌
し反応させた後、室温で24時間静置して熟成を行
つた。この水性スラリーの沈降体積は８cm3／ｇで
あり、生成物はゲルであつた。この水性スラリー
に耐アルカリガラス繊維を３部及び比較例４のみ
はさらに天然β−CaO・SiO2を全固形分に対し
30重量％となるように添加した。その後の工程は
実施例１と同様に行つて表１の結果を得た。
比較例 ６
生石灰（96.2％CaO）49.6部に温水を加え消化
し、これに珪石（96.4％SiO2）50.4部を添加した
後、総水量が固形分に対し27.5部になるように水
を加えた。このようにして得られた懸濁液をオー
トクレーブ中で15Kg／cm2Ｇ、200℃の条件下で4.0
時間撹拌し反応させたところ、沈降体積21cm3／ｇ
のゾノトライトを含む水性スラリーが得られた。
この水性スラリーに耐アルカリガラス繊維３部及
びワラストナイト（天然β−CaO・SiO2）10重
量％を添加し嵩密度が0.20ｇ／cm3になるようにス
ラリーを調製し、300×300×50mm（縦×横×厚
さ）の寸法に10Kg／cm2の圧力にて加圧脱水成形し
た。次いで得られた成形体を150℃で８時間乾燥
した。表１にプレス時間、乾燥後の板厚収縮率、
嵩密度、曲げ強度及び、1000℃３時間加熱後の残
存収縮率と重量減少％を示した。該成形体は、実
施例１〜５のトバモライトグループの化合物から
なる珪酸カルシウム水和物を含む水性スラリーを
用いた場合に比べ、プレス時間が長く、曲げ強度
を劣るものであつた。
比較例 ７
ワラストナイト（β−CaO・SiO2）を50重量
％添加すること以外は比較例６と同様に行つて表
１の結果を得た。該成形体は実施例１〜５のトバ
モライトグループの化合物から成る珪酸カルシウ
ム水和物を含む水性スラリーを用いた場合に比
べ、強度の著しく劣るものであつた。
The present invention relates to a method for producing a calcium silicate molded body. For details, see low bulk density, heat resistance,
The present invention relates to a method for producing a calcium silicate molded body that has excellent mechanical strength and dimensional stability and is therefore suitable as a heat insulating material and a heat insulating material. Calcium silicate molded bodies, especially those containing xonotlite as a main component, have heat resistance of 1000°C or higher and are therefore suitable as heat insulators and heat insulating materials. in general,
Calcium silicate molded bodies used as heat insulators and heat insulators are required to have low thermal conductivity and high mechanical strength. However, in order to lower the thermal conductivity, it is necessary to produce a molded product with a low bulk density, but as the bulk density decreases, the strength also decreases, so a molded product with a low bulk density and high mechanical strength is produced. It is extremely difficult to manufacture. Some of the present inventors have proposed a method for producing such a molded body by dehydrating an aqueous slurry containing a specific calcium silicate hydrate and then curing it with steam. I suggested to the target that it was effective. (Japanese Patent Application No. 52-63621) (Japanese Patent Publication No. 58-30259) This method is extremely advantageous, but since the calcium silicate hydrate during dehydration molding is very bulky, the molding pressure is high. Molding work takes time. In addition, there was a further problem that should be improved, that is, the molded product contracts in the direction of the molding pressure. In view of this point, the present inventors conducted extensive research and found that
If wollastonite is added to a slurry consisting essentially of a specific calcium silicate hydrate and then molded, followed by steam curing, the moldability is good and compared to calcium silicate molded bodies obtained by conventional methods. If the bulk specific gravity is the same, it has higher bending strength,
The inventors have discovered that a calcium silicate molded body having a lower bulk specific gravity can be obtained with the same bending strength, and have arrived at the present invention. That is, the gist of the present invention is to provide a hydrated calcium silicate comprising a tobermorite group compound with a sedimentation volume of 15 cm 3 /g or more obtained by reacting a calcareous raw material and a silicate raw material dispersed in water under heating. In a method for producing a calcium silicate molded body by dehydrating and molding an aqueous slurry substantially consisting of a substance, and then curing with steam, the aqueous slurry is added with wollastonite in the molded body.
The present invention provides a method for producing a calcium silicate molded article, characterized in that the calcium silicate molded article is added to the calcium silicate molded body in an amount of up to 60% by weight. The present invention will be described in detail below. In the method of the present invention, the silicic acid raw materials include natural products such as diatomaceous earth and silica stone, silicon dust, and hydrosilicic acid and aluminum hydroxide which are by-products of the wet phosphoric acid manufacturing process. Industrial by-products such as silica (hereinafter simply referred to as wet phosphoric acid by-product silica) obtained by reacting are used. Further, as the calcareous raw material, any of the well-known materials such as quicklime, slaked lime, and carbide slag can be used, but quicklime is particularly suitable. Mixing molar ratio of siliceous raw material and calcareous raw material (CaO/
SiO 2 ) is usually within the range of 0.8 to 1.2 when xonotlite is desired as a crystal of calcium silicate hydrate in the final molded product, and is usually within the range of 0.7 to 1.0 when crystalline tobermorite is desired. be. The amount of water for dispersing both of the raw materials may be at least 15 times the solid content of the raw materials, particularly 17 to 40 times the solid content of the raw materials.
A range of times the weight is preferred. Of course, if the water in the calcareous raw material-containing slurry is insufficient to disperse both raw materials, more water may be added. By reacting the above-mentioned raw materials dispersed in water under heating, an aqueous slurry containing calcium silicate hydrate crystals can be obtained. The settling volume of calcium silicate hydrate crystals in the aqueous slurry is 15 cm 3 /g or more, preferably 15 to 30
cm 3 /g. Sedimentation volume is 15
If it is lower than cm 3 /g, a molded article with high strength cannot be obtained. Here, the sedimentation volume is a value calculated by the following equation (). Sedimentation volume = V/W... () In formula (), W is the total weight of the raw material solid content (e.g. quicklime + silicic raw material) (if calcareous raw materials other than quicklime are used, calculate the total weight by converting to quicklime) ), and V is the volume occupied by the solid content that settled after the slurry obtained after the reaction was allowed to stand for 24 hours. In practice, it is usually determined as follows. First, from the slurry with a total weight of W 0 g obtained after the reaction, W 1 g
was collected in a graduated cylinder, left to stand for 24 hours, and the volume occupied by the settled solids, V 1 cm 3 , was measured.
Calculated using the following formula (). Sedimentation volume=V 1 /W 1 ×W/W 0 () Note that W has the same meaning as in formula () and indicates the total weight of the raw materials. The method of increasing the sedimentation volume to 15 cm 3 /g or more is as follows:
The reaction is carried out under stirring at 130°C or higher, especially at 150-230°C.
The most suitable method is a method carried out at 160 to 210°C. In this case, the reaction system must be kept in a liquid state, and therefore the reaction is carried out under pressure. Furthermore, it is necessary that the slurry consists essentially of calcium silicate hydrate consisting of a compound of the tobermorite group. Various types of calcium silicate hydrate crystals are known, and they are generally described in "The Chemistry of Cement" by HFWTaylor.
Cements) Volume 1, page 182 Tobermorite group compounds include tobermorite gel, C-S-H(), C-S-
H() and crystalline tobermorite are included,
It may be either. Calcium silicate hydrate crystals are produced by tobermorite gel → C-S-H ()
Since the transition normally occurs in the order of →C-S-H() → 11 Å tobermorite (crystalline tobermorite) → xonotrite, it is sufficient to adjust the reaction temperature and time to obtain the desired crystal. In other words, if the reaction temperature is increased or the reaction time is increased,
The crystals transfer in the direction of the arrow (→) mark. If the reaction is carried out in a temperature range to achieve the first condition,
Compounds of the tobermorite group are usually obtained.
However, if the reaction temperature is particularly high or the reaction time is particularly long, xonotlite will be obtained, so in that case, the temperature may be lowered or the reaction time may be shortened. In addition, when crystalline tobermorite is desired as crystals in the final molded product, the calcium silicate hydrate in the slurry is tobermorite gel, C-S-
It must be H() or C-S-H(). In the present invention, wollastonite is added to the aqueous slurry. What does wollastonite refer to here? “Gypsum Lime Handbook” edited by the Gypsum and Lime Society
It is a general term for the items explained on pages 271 to 275, and can be classified as follows. Namely, wollastonite (chemical formula CaO・SiO 2 )
are low-temperature type (β-CaO・SiO 2 ) and high-temperature type (α-
It is classified into two types: CaO and SiO 2 ). The low-temperature type changes to the high-temperature type at temperatures above about 1125℃. Low-temperature types include natural products and synthetic products obtained by heating and dehydrating xonotlite, while high-temperature types are mainly synthetic products. The wollastonite used in the present invention may be any of the above-mentioned types, but particularly preferred is a low-temperature type natural product with significant fibrous crystals. The amount of wollastonite added is preferably 5 to 60% by weight, preferably 10 to 50% by weight, particularly preferably 10 to 35% by weight in the final molded product. If it is less than 10% by weight, a sufficient effect in terms of moldability cannot be obtained, and if it is more than 50% by weight, it will not be possible to reduce the weight of the molded product, and the amount of calcium silicate hydrate forming the matrix will be relatively low. As a result, the mechanical strength of the molded article decreases, which is undesirable. In the present invention, reinforcing fibers are usually added to the aqueous slurry. Any of a variety of well-known reinforcing fibers can be used, such as asbestos, rock wool, glass fiber, and the like. It is usually added to the final molded product in an amount of 0.5 to 10% by weight. The aqueous slurry thus obtained is subjected to pressure dehydration molding according to a conventional method. The pressure at that time is usually 1
~200 Kg/cm 2 G, and the bulk specific gravity of the molded product is adjusted by adjusting the piston stroke of the pressure molding machine. Next, the obtained molded body is subjected to steam curing under pressure, so-called autoclave curing, according to a conventional method. By this steam curing, the crystals of the molded body are removed from tobermorite gel, C-S-H () or C-S-H ().
In this case, it is necessary to transform it into crystalline tobermorite or xonotlite, and in the case of crystalline tobermorite, it is necessary to transform it into xonotlite. The crystal transformation caused by this steam curing makes it possible to obtain a molded article with low bulk density and excellent mechanical strength. In general, the higher the water vapor pressure, the shorter the reaction time, but usually 5~
It is in the range of 50Kg/cm 2 G. 12 to 40 kg/cm 2 if xonotlite is desired as the crystal of the final molded product.
G, 6 to 6 when crystalline tobermorite is desired
30Kg/cm 2 G steam is preferred. Under such conditions, the above-mentioned transfer is usually easily carried out.
If the transformation does not occur as desired, which is extremely rare, for example, if xonotlite is desired but crystalline tobermorite is obtained, increasing the steam pressure or extending the steam curing time will solve the problem. If crystalline tobermorite is desired but xonotlite is obtained, conversely, the steam pressure can be lowered or the steam curing time can be shortened. In applications requiring high heat resistance, it is preferable to transform it into xonotlite. The present invention has been described in detail above. According to the method of the present invention, a material with a bulk density of about 0.15 g/cm 2 has a bending strength of 10 Kg/cm 2 or more, and a material with a bending strength of about 0.20 g/cm 2 has a bending strength of 15 kg/cm 2 or more.
The calcium silicate molded product has a bending strength of Kg/cm 2 or more, which is about twice as high as the molded product obtained by conventional methods at the same bulk density, and has excellent moldability in terms of molding pressure and molding speed, and is dimensionally stable. You can get it easily. Furthermore, the resulting molded product has excellent heat resistance due to the intertwining of heat-resistant wollastonite and matrix of calcium silicate hydrate crystals. It can be expected to have a wide range of applications as a fireproof insulation material for various industrial applications in furnaces, drying furnaces, ducts, and the aluminum industry. Next, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. In the examples, "parts" and "%" refer to "parts by weight" and "% by weight." Examples 1 to 5 and Comparative Examples 1 to 3 After adding warm water to 49.6 parts of quicklime (96.2% CaO) and digesting it, and adding 50.4 parts of silica stone (96.4% SiO 2 ) to this, the total water amount was Water was added to make 27.5 parts. When the suspension thus obtained was stirred and reacted in an autoclave at 15 kg/cm 2 G and 200°C for 2.0 hours, the sedimentation volume was
An aqueous slurry containing 21 g/cm 2 of CSH was obtained.
To this aqueous slurry, 3 parts of alkali-resistant glass fiber and wollastonite were added in the types and amounts shown in Table 1 (alumina was added in Comparative Example 3), and the slurry was made to have a bulk density of 0.20 (0.15 in Example 4 only). Adjust 10 to the dimensions of 300 x 300 x 50 mm (length x width x thickness)
Pressure dehydration molding was performed at a pressure of Kg/cm 2 . Next, the obtained molded body was placed in an autoclave and steamed 11
Kg/cm 2 G After steam curing for 5 hours at 187°C, it was dried at 150°C for 8 hours. Table 1 shows press time,
Thickness shrinkage rate, bulk density, bending strength and 1000 after drying
The residual shrinkage rate and weight loss percentage after heating for 3 hours at °C are shown. Comparative Examples 4-5 46.7 parts of quicklime (96.2% CaO) was digested by adding warm water, and silica (wet phosphoric acid by-product silica) was added to this to digest it.
After adding 49.2 parts of SiO 2 (97.8%), water was added so that the total amount of water was 10 times the solid content by weight. The suspension thus obtained was stirred at 90° C. for 2 hours to react, and then allowed to stand at room temperature for 24 hours to ripen. The settling volume of this aqueous slurry was 8 cm 3 /g, and the product was a gel. 3 parts of alkali-resistant glass fiber was added to this aqueous slurry, and only in Comparative Example 4, natural β-CaO・SiO 2 was added to the total solid content.
It was added at a concentration of 30% by weight. The subsequent steps were carried out in the same manner as in Example 1, and the results shown in Table 1 were obtained. Comparative Example 6 49.6 parts of quicklime (96.2% CaO) was added to digest it with warm water, 50.4 parts of silica stone (96.4% SiO 2 ) was added thereto, and then water was added so that the total amount of water was 27.5 parts based on the solid content. Ta. The suspension thus obtained was placed in an autoclave at 15 Kg/cm 2 G and 200°C under the conditions of 4.0
When the reaction was stirred for hours, the sedimentation volume was 21cm 3 /g.
An aqueous slurry containing 100% of xonotlite was obtained.
To this aqueous slurry, 3 parts of alkali-resistant glass fibers and 10% by weight of wollastonite (natural β-CaO SiO 2 ) were added to prepare a slurry with a bulk density of 0.20 g/cm 3 and a 300×300× Pressure dehydration molding was performed at a pressure of 10 Kg/cm 2 to a size of 50 mm (length x width x thickness). The obtained molded body was then dried at 150°C for 8 hours. Table 1 shows the pressing time, plate thickness shrinkage rate after drying,
The bulk density, bending strength, residual shrinkage rate and weight loss percentage after heating at 1000°C for 3 hours are shown. The molded product required a longer pressing time and had lower bending strength than the case of Examples 1 to 5 in which an aqueous slurry containing calcium silicate hydrate made of a compound of the tobermorite group was used. Comparative Example 7 The results shown in Table 1 were obtained in the same manner as in Comparative Example 6 except that 50% by weight of wollastonite (β-CaO.SiO 2 ) was added. The strength of the molded product was significantly inferior to that of Examples 1 to 5 in which an aqueous slurry containing calcium silicate hydrate made of a compound of the tobermorite group was used.
【表】
＊＊ 小野田セメント社製
＊＊＊ 電解用アルミナ
[Table] ** Manufactured by Onoda Cement *** Alumina for electrolysis
Claims (1)
を加熱下反応させて得られる沈降体積が15cm3／ｇ
以上のトバモライトグループの化合物からなる珪
酸カルシウム水和物から実質的に構成される水性
スラリーを脱水成形した後、水蒸気養生すること
により珪酸カルシウム成形体を製造する方法にお
いて、該水性スラリーに、ワラストナイトを成形
体中に５〜60重量％含有するように添加すること
を特徴とする珪酸カルシウム成形体の製造方法。1 The sedimentation volume obtained by reacting calcareous raw materials and silicic raw materials dispersed in water under heating is 15 cm 3 /g.
In a method for producing a calcium silicate molded body by dehydrating and molding an aqueous slurry substantially consisting of calcium silicate hydrate made of the above-mentioned tobermorite group compounds, the aqueous slurry is coated with wollast. 1. A method for producing a calcium silicate molded body, which comprises adding night to the molded body in an amount of 5 to 60% by weight.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP634782A JPS58125653A (en) | 1982-01-19 | 1982-01-19 | Manufacture of calcium silicate shape |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP634782A JPS58125653A (en) | 1982-01-19 | 1982-01-19 | Manufacture of calcium silicate shape |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58125653A JPS58125653A (en) | 1983-07-26 |
| JPH0338226B2 true JPH0338226B2 (en) | 1991-06-10 |
Family
ID=11635834
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP634782A Granted JPS58125653A (en) | 1982-01-19 | 1982-01-19 | Manufacture of calcium silicate shape |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58125653A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62223051A (en) * | 1986-03-25 | 1987-10-01 | 三菱鉱業セメント株式会社 | Formed body for glazing and manufacture of glazed formed body |
| US7513684B2 (en) * | 2005-02-17 | 2009-04-07 | Parker-Hannifin Corporation | Calcium silicate hydrate material for use as ballast in thermostatic expansion valve |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS52135330A (en) * | 1976-05-10 | 1977-11-12 | Nippon Asbestos Co Ltd | Production of calcium silicate boad free from asbestos |
| JPS54108822A (en) * | 1976-09-17 | 1979-08-25 | Johns Manville | High density wollostoniteecontaining tobermolite heat insulator free of asbestos |
| JPS54109653A (en) * | 1978-01-30 | 1979-08-28 | Johns Manville | Highhdensity nonnasbestos tvelumolite heat insulator |
| JPS54135819A (en) * | 1978-04-14 | 1979-10-22 | Mitsubishi Chem Ind | Production of calcium silicate formed body |
| JPS55167167A (en) * | 1979-05-15 | 1980-12-26 | Nippon Asbestos Co Ltd | Manufacture of calcium silicate heat resistant material |
| JPS577815A (en) * | 1980-06-13 | 1982-01-16 | Masayoshi Aoki | Calcium silicate hydrate-base aggregate |
-
1982
- 1982-01-19 JP JP634782A patent/JPS58125653A/en active Granted
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS52135330A (en) * | 1976-05-10 | 1977-11-12 | Nippon Asbestos Co Ltd | Production of calcium silicate boad free from asbestos |
| JPS54108822A (en) * | 1976-09-17 | 1979-08-25 | Johns Manville | High density wollostoniteecontaining tobermolite heat insulator free of asbestos |
| JPS54109653A (en) * | 1978-01-30 | 1979-08-28 | Johns Manville | Highhdensity nonnasbestos tvelumolite heat insulator |
| JPS54135819A (en) * | 1978-04-14 | 1979-10-22 | Mitsubishi Chem Ind | Production of calcium silicate formed body |
| JPS55167167A (en) * | 1979-05-15 | 1980-12-26 | Nippon Asbestos Co Ltd | Manufacture of calcium silicate heat resistant material |
| JPS577815A (en) * | 1980-06-13 | 1982-01-16 | Masayoshi Aoki | Calcium silicate hydrate-base aggregate |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58125653A (en) | 1983-07-26 |
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