JPS6128622B2 - - Google Patents
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- Publication number
- JPS6128622B2 JPS6128622B2 JP55147376A JP14737680A JPS6128622B2 JP S6128622 B2 JPS6128622 B2 JP S6128622B2 JP 55147376 A JP55147376 A JP 55147376A JP 14737680 A JP14737680 A JP 14737680A JP S6128622 B2 JPS6128622 B2 JP S6128622B2
- Authority
- JP
- Japan
- Prior art keywords
- refractories
- weight
- unfired
- spinel
- parts
- 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.)
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- 239000011230 binding agent Substances 0.000 claims description 16
- 239000000203 mixture Substances 0.000 claims description 16
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims description 13
- 239000003513 alkali Substances 0.000 claims description 13
- 229910019142 PO4 Inorganic materials 0.000 claims description 12
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 7
- 239000002245 particle Substances 0.000 claims 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 claims 1
- 239000010452 phosphate Substances 0.000 claims 1
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 46
- 239000011819 refractory material Substances 0.000 description 39
- 239000000395 magnesium oxide Substances 0.000 description 23
- 229910052596 spinel Inorganic materials 0.000 description 21
- 239000011029 spinel Substances 0.000 description 21
- 235000021317 phosphate Nutrition 0.000 description 11
- 150000003013 phosphoric acid derivatives Chemical class 0.000 description 11
- 239000000126 substance Substances 0.000 description 11
- 238000010304 firing Methods 0.000 description 10
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical class O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 9
- 238000004901 spalling Methods 0.000 description 9
- 239000002994 raw material Substances 0.000 description 8
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 230000006866 deterioration Effects 0.000 description 4
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 description 3
- 239000004568 cement Substances 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 230000000704 physical effect Effects 0.000 description 3
- 239000000377 silicon dioxide Substances 0.000 description 3
- 239000011734 sodium Substances 0.000 description 3
- 239000001577 tetrasodium phosphonato phosphate Substances 0.000 description 3
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 2
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- TWRXJAOTZQYOKJ-UHFFFAOYSA-L Magnesium chloride Chemical compound [Mg+2].[Cl-].[Cl-] TWRXJAOTZQYOKJ-UHFFFAOYSA-L 0.000 description 2
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 2
- 229920000388 Polyphosphate Polymers 0.000 description 2
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 2
- 239000011822 basic refractory Substances 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 229910052500 inorganic mineral Inorganic materials 0.000 description 2
- 159000000003 magnesium salts Chemical class 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 235000010755 mineral Nutrition 0.000 description 2
- 239000011707 mineral Substances 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 239000001205 polyphosphate Substances 0.000 description 2
- 235000011176 polyphosphates Nutrition 0.000 description 2
- 239000011591 potassium Substances 0.000 description 2
- 229910052700 potassium Inorganic materials 0.000 description 2
- 229910052708 sodium Inorganic materials 0.000 description 2
- GCLGEJMYGQKIIW-UHFFFAOYSA-H sodium hexametaphosphate Chemical compound [Na]OP1(=O)OP(=O)(O[Na])OP(=O)(O[Na])OP(=O)(O[Na])OP(=O)(O[Na])OP(=O)(O[Na])O1 GCLGEJMYGQKIIW-UHFFFAOYSA-H 0.000 description 2
- 235000019982 sodium hexametaphosphate Nutrition 0.000 description 2
- 239000001488 sodium phosphate Substances 0.000 description 2
- 229910000162 sodium phosphate Inorganic materials 0.000 description 2
- 235000019832 sodium triphosphate Nutrition 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 229910052566 spinel group Inorganic materials 0.000 description 2
- RYFMWSXOAZQYPI-UHFFFAOYSA-K trisodium phosphate Chemical compound [Na+].[Na+].[Na+].[O-]P([O-])([O-])=O RYFMWSXOAZQYPI-UHFFFAOYSA-K 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 1
- MKYBYDHXWVHEJW-UHFFFAOYSA-N N-[1-oxo-1-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)propan-2-yl]-2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidine-5-carboxamide Chemical compound O=C(C(C)NC(=O)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F)N1CC2=C(CC1)NN=N2 MKYBYDHXWVHEJW-UHFFFAOYSA-N 0.000 description 1
- 239000011398 Portland cement Substances 0.000 description 1
- 239000004111 Potassium silicate Substances 0.000 description 1
- 239000004115 Sodium Silicate Substances 0.000 description 1
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- XFWJKVMFIVXPKK-UHFFFAOYSA-N calcium;oxido(oxo)alumane Chemical compound [Ca+2].[O-][Al]=O.[O-][Al]=O XFWJKVMFIVXPKK-UHFFFAOYSA-N 0.000 description 1
- 239000011233 carbonaceous binding agent Substances 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 229910000423 chromium oxide Inorganic materials 0.000 description 1
- 239000011294 coal tar pitch Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 230000001010 compromised effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 239000011396 hydraulic cement Substances 0.000 description 1
- 230000008595 infiltration Effects 0.000 description 1
- 238000001764 infiltration Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- PAZHGORSDKKUPI-UHFFFAOYSA-N lithium metasilicate Chemical compound [Li+].[Li+].[O-][Si]([O-])=O PAZHGORSDKKUPI-UHFFFAOYSA-N 0.000 description 1
- 229910052912 lithium silicate Inorganic materials 0.000 description 1
- 229910001629 magnesium chloride Inorganic materials 0.000 description 1
- 229910052943 magnesium sulfate Inorganic materials 0.000 description 1
- 235000019341 magnesium sulphate Nutrition 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000005011 phenolic resin Substances 0.000 description 1
- OQZCJRJRGMMSGK-UHFFFAOYSA-M potassium metaphosphate Chemical compound [K+].[O-]P(=O)=O OQZCJRJRGMMSGK-UHFFFAOYSA-M 0.000 description 1
- 229940099402 potassium metaphosphate Drugs 0.000 description 1
- 229910052913 potassium silicate Inorganic materials 0.000 description 1
- 235000019353 potassium silicate Nutrition 0.000 description 1
- NNHHDJVEYQHLHG-UHFFFAOYSA-N potassium silicate Chemical compound [K+].[K+].[O-][Si]([O-])=O NNHHDJVEYQHLHG-UHFFFAOYSA-N 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- FQENQNTWSFEDLI-UHFFFAOYSA-J sodium diphosphate Chemical compound [Na+].[Na+].[Na+].[Na+].[O-]P([O-])(=O)OP([O-])([O-])=O FQENQNTWSFEDLI-UHFFFAOYSA-J 0.000 description 1
- 229940048086 sodium pyrophosphate Drugs 0.000 description 1
- 229910052911 sodium silicate Inorganic materials 0.000 description 1
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000011010 synthetic spinel Substances 0.000 description 1
- RYCLIXPGLDDLTM-UHFFFAOYSA-J tetrapotassium;phosphonato phosphate Chemical compound [K+].[K+].[K+].[K+].[O-]P([O-])(=O)OP([O-])([O-])=O RYCLIXPGLDDLTM-UHFFFAOYSA-J 0.000 description 1
- 235000019818 tetrasodium diphosphate Nutrition 0.000 description 1
- UNXRWKVEANCORM-UHFFFAOYSA-I triphosphate(5-) Chemical compound [O-]P([O-])(=O)OP([O-])(=O)OP([O-])([O-])=O UNXRWKVEANCORM-UHFFFAOYSA-I 0.000 description 1
- 239000011452 unfired brick Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Description
本発明は主成分がマグネシア・アルミナから成
る不焼成耐火物に関するものである。近年耐火物
の変遷に伴ない、マグネシア・アルミナ系耐火
物、鉱物組成的にはマグネシア−スピネル
（MgO・Al2O3）耐火物（以下スピネル耐火物を略
す）が取鍋等の製鉄炉、セメントロータリーキル
ン等の非鉄工業炉の内張り用耐火物として注目を
集めつゝあることは周知の所である。かかるスピ
ネル耐火物が使用され始めた理由はマグネシア含
有耐火物としては、他に類のない熱的スポーリン
グ抵抗性を有すること、及びスライダ浸潤に基因
する構造的スポーリングが少ないこと等が挙げら
れるが、無論溶媒スラグに対する耐食性も塩基性
耐火物共通の優位性を保つている。スピネル耐火
物の製造法は一般に高温で死焼されたマグネシア
クリンカーと、主としてMgO・Al2O3の鉱物組成
から成る合成スピネルクリンカーを配合し、高温
で焼成することから成るが、これに加えてアルミ
ナ原料を使用し、焼成時にマグネシアとの反応に
よる二次スピネルを生成せしめる手法がとられる
場合もある。しかしいずれにしてもその焼成温度
は1500℃以上、好ましくは1700℃付近まで高める
必要があり、近年のように燃料コストが急騰して
いる背景下では、製品コストに占める焼成コスト
の比率が極めて大きくなる欠点を有している。ま
た省エネルギーという観点からも高温焼成を前提
とする耐火物は好ましくなく、可能な限り低温焼
成で製品化し得る耐火物の開発が望まれている。
このような最近の趨勢下では高々200℃の加熱処
理で製品となる不焼成耐火物が最も好ましいが、
スピネル耐火物においては未だ不焼成耐火物が提
案されるに至つていない。
この理由に関しては種々の事項が考えられる
が、特に低温から高温迄の全温度域で優れた強度
特性を付与せしめるのが極めて困難であること、
及び不焼成耐火物に不可欠な結合剤が骨材に比較
して耐熱性に劣る為、耐火物使用中の容積安定
性、耐食性、耐スポーリング性等が焼成耐火物よ
りも格段に劣ることに原因しているものと解釈さ
れる。
本発明はかかる従来の不焼成耐火物の欠点を可
能な限り解消し、焼成耐火物と同等な性能を付与
すべく鋭意研究の末に完成されたものであり、具
体的には一定範囲の化学組成を有する一種以上の
骨材に結合剤として縮合りん酸アルカリ類を配合
して成るものである。
結合剤に関しては従来から種々の物質が提案さ
れているが、これらの内塩基性耐火物に使用可能
なものとして次のようなものを挙げることができ
る。
(1) 塩化マグネシウム、硫酸マグネシウム等のマ
グネシウム塩
(2) SiO2／R2Oモル比が２以上の珪酸ナトリウ
ム、珪酸カリウム及び珪酸リチウム
(3) 特殊に変性されたコロイダルシリカ又は蒸発
シリカ、ゲル状シリカ等の無定形シリカ
(4) 縮合りん酸ナトリウムに代表される縮合りん
酸アルカリ類
(5) ポルトランドセメント、アルミナセメントに
代表される水硬性セメント類
(6) フエノール樹脂、コールタールピツチに代表
される炭素質結合剤
本発明者は上記の中でスピネル耐火物に適する
結合剤を詳細に検討した結果、骨材の化学組成が
MgO70〜95重量部、Al2O35〜25重量部、CaO0.1
〜５重量部、残余が各々１重量部以下のSiO2、
Fe2O3、B2O3等の範囲にあるとき、縮合りん酸ア
ルカリ類が極めて優れた性状を示し、高温で焼成
された耐火物と同等の性能を有する不焼成耐火物
が得られることを見い出した。他の結合剤に比較
した縮合りん酸アルカリ類の優位性は随所にみら
れるが、例えば(1)のマグネシウム塩との比較では
800℃〜1400℃の温度域における強度が格段に優
れ、また(2)(3)(5)のシリカ系結合剤、セメント類と
の比較では加熱、冷却に伴ない容積安定性及び使
用中のスポーリングに対する抵抗性等に関して優
れている。ここで特に加熱、冷却時の容積安定性
は従来不焼成耐火物の欠点として指適されていた
もので、耐火物の目地損耗、部分的な脱落を防止
する意味で極めて重要である。
(6)の炭素質結合剤に比較した優位性は言うまで
もなく、酸化性雰囲気下において強度の劣化を生
じないことにある。
本発明はかかる縮合りん酸アルカリ類を使用し
ているが、その使用量に関しては骨材100重量部
に対して１〜４重量部が好適である。１重量部よ
り少ない範囲では不焼成耐火物の強度を満足させ
るのに充分でなく、４重量部より多い範囲では耐
熱性に乏しい結合剤量が必要以上に増大し、耐火
物使用中の焼結現象が促進されることから、加熱
冷却時の容積安定性、熱的スポーリングに対する
抵抗性が著しく劣化して好ましくない。また縮合
りん酸アルカリ類以外の例えば前述の(1)〜(3)及び
(5)(6)のような結合剤の併用は、縮合りん酸アルカ
リ類が主たる結合剤である範囲、具体的には水、
溶剤を除去した結合剤の固型分換算で縮合りん酸
アルカリ類の重量％を越えない範囲で使用するこ
とができる。本発明に使用される縮合リン酸アル
カリ類とは具体的にはR2O／P2O5のモル比1.5／
１〜１／１の組成範囲を有するものに限定される
が、これはR2O／P2O5モル比1.5／１よりR2Oが
多いもの、即ちピロりん酸ソーダ、トリポリりん
酸ソーダ、ピロりん酸カリウム、トリポリりん酸
カリウム等はマグネシア及びスピネル原料との化
学結合速度が大であり、耐火物製造工程上の弊害
を生ずると同時に耐熱性劣化の原因となるアルカ
リ成分が増大して好ましくない。またR2O／P2O5
のモル比が１／１よりアルカリ成分の少ない範
囲、即ちウルトラポリりん酸塩はPHがかなりの酸
性域である為、塩基性原料との反応が極めてすみ
やかに起こり、不焼成耐火物の結合剤としては不
適である。上記のような制約から本発明に使用で
きる結合剤としてはテトラポリりん酸ソーダ、ペ
ンタポりりん酸ソーダ、ヘキサメタりん酸ソー
ダ、テトラポリりん酸カリウム、メタりん酸カリ
ウム等が挙げられるが、必ずしもこれらに限定さ
れる訳ではなく、前述のR2O／P2O5モル比を有す
るものであれば如何なるものを使用することがで
きる。本発明はかかる組成範囲を有する縮合りん
酸アルカリ類を使用して成るが、不焼成耐火物の
性能を可能な限り向上せしめるには使用する骨材
の化学組成を一定範囲に調整することが必要であ
り、具体的にはMgO70〜95重量部、Al2O35〜25
重量部、CaO0.1〜５重量部、残余が各々１重量
部以下のSiO2、Fe2O3、B2O3等から構成されなけ
ればならない。ここでAl2O3が５重量部より少な
い範囲、即ちMgO・Al2O3のスピネルに換算して
約７重量部以下ではスピネル耐火物の特徴である
熱的スポーリングに対する抵抗性等が著しく劣化
し、マグネシア耐火物に類似した性状となり好ま
しくない。またAl2O3が25重量部を越える範囲で
はMgO・Al2O3換算で約35量部以上となり、この
スピネルが難焼結性であることから不焼成耐火物
使用中に著しい強度劣化を生じ、組織の危弱化を
もたらすので不適である。
CaOは塩基性原料に少なからず含有されている
ものであり、その適度な存在は原料中のシリケー
ト組成を高融点化せしめるのに有効であり、不焼
成耐火物においては特に熱間の強度向上に寄与す
るものであるが、本発明のスピネル耐火物におい
てはAl2O3が共存する為、CaOの過剰な存在は例
えば低融点のカルシウムアルミネート等を生成
し、熱間性状、容積安定性等を劣化させるので、
その量は５重量部以下より好ましくは３重量部以
下に規制する必要がある。また下限については、
特に制約はないが原料の特性上0.1重量部以下に
することは不可能である。SiO2を始めとする不
純物の量は本発明の不焼成スピネル耐火物におけ
る使用中の容積安定性、耐熱性、熱的スポーリン
グに対する抵抗性等の点で極めて重要である。一
般の塩基性原料中に含有されるSiO2以外の不純
物は微量であり、弊害となることは少ないが、
SiO2に関してはその量が１重量部を越えた場合
縮合りん酸アルカリ類を使用した本発明の耐火物
の性能を著しく劣化せしめるので、かかる骨材の
使用は不適である。以上のような化学組成範囲に
限定された条件下で本発明に使用される骨材とし
ては、焼結マグネシア、電融マグネシア並びに
種々の化学組成を有し、鉱物組成的にMgO・
Al2O3のスピネル及びMgO又はAl2O3から成る焼
結、電融スピネル等を挙げることができる。
不焼成耐火物使用中にスピネルを生成せしめる
ことを目的として高純度なアルミナ原料も使用す
ることができるが、かかる反応が膨張反応である
ことから温度の添加は使用中に耐火物の組織劣化
もをたらすので好ましくない。また酸化クロムは
本発明の不焼成耐火物に何ら悪影響を及ぼすもの
ではなく、例外的に使用することができるが、シ
リケート、酸化鉄を多量に含有したクロム鉱等は
本発明による化学組成範囲内に限定される。
本発明による不焼成耐火物を詳細に説明する為
以下に実施例を示す。
実施例 １
骨材に焼結マグネシア、焼結スピネルクリンカ
ーを使用し、その比率を種々変えて不焼成耐火物
を製造した。スピネルクリンカーはその大部分が
MgO・Al2O3のスピネルから成り、微量のフリー
のMgOを含有している。結合剤には市販のヘキ
サメタりん酸ソーダ（Na2O：30.6重量％、
P2O5：69.0重量％）を外掛け２％使用し、既知の
方法で混練、成型した後170℃で10時間乾燥し
た。使用中の状態、即ち受熱後の状態を知る為に
1600℃で６時間焼成し、焼成後の試料の品質及び
熱的スポーリングに対する抵抗性を調査した。
製造した不焼成耐火物の化学組成（結合剤成分
を除く）を第１表に、不焼成耐火物の物性値及び
焼成後の物性値を第２表に示した。なお実施例１
−４にのみ焼結アルミナが３重量部使用されてい
る。本発明の範囲よりアルミナ（スピネル）が少
ない範囲では焼成後の容積安定性、耐スポーリン
グ性が著しく劣化し、また多い範囲では焼成後の
強度劣化が顕著にみられ、本発明の範囲にある不
焼成耐火物の優秀さを立証した。
The present invention relates to an unfired refractory whose main components are magnesia and alumina. In recent years, with the changes in refractories, magnesia/alumina refractories, mineral compositions such as magnesia-spinel (MgO・Al 2 O 3 ) refractories (hereinafter referred to as spinel refractories), have been used in iron making furnaces such as ladles, It is well known that it is attracting attention as a refractory for lining non-ferrous industrial furnaces such as cement rotary kilns. The reason why such spinel refractories have started to be used is that they have unparalleled thermal spalling resistance among magnesia-containing refractories, and that there is little structural spalling caused by slider infiltration. However, corrosion resistance against solvent slag also maintains a common advantage among basic refractories. The manufacturing method for spinel refractories generally consists of blending magnesia clinker dead-fired at high temperature with synthetic spinel clinker mainly composed of MgO Al 2 O 3 mineral composition and firing at high temperature. In some cases, a method is used in which an alumina raw material is used and a secondary spinel is produced by reaction with magnesia during firing. However, in any case, the firing temperature needs to be raised to 1,500℃ or higher, preferably around 1,700℃, and with fuel costs soaring in recent years, the ratio of firing costs to product costs is extremely large. It has some drawbacks. Moreover, from the viewpoint of energy saving, refractories that require high-temperature firing are not preferred, and there is a desire to develop refractories that can be manufactured by firing at as low a temperature as possible.
Under these recent trends, unfired refractories that can be made into products by heat treatment at a temperature of at most 200°C are the most preferred.
Among spinel refractories, unfired refractories have not yet been proposed. There are various possible reasons for this, but in particular it is extremely difficult to impart excellent strength properties over the entire temperature range from low to high temperatures.
And because the binder essential for unfired refractories has inferior heat resistance compared to aggregate, the volume stability, corrosion resistance, spalling resistance, etc. during use of refractories are significantly inferior to fired refractories. It is interpreted as being the cause. The present invention was completed after intensive research in order to eliminate the drawbacks of conventional unfired refractories as much as possible and provide performance equivalent to that of fired refractories. It is made by blending condensed alkali phosphates as a binder with one or more aggregates having the following composition. As for the binder, various substances have been proposed in the past, and the following can be mentioned as those that can be used for these internally basic refractories. (1) Magnesium salts such as magnesium chloride and magnesium sulfate (2) Sodium silicate, potassium silicate, and lithium silicate with a SiO 2 /R 2 O molar ratio of 2 or more (3) Specially modified colloidal silica or evaporated silica, gel Amorphous silica such as silica (4) Condensed alkali phosphates such as condensed sodium phosphate (5) Hydraulic cements such as Portland cement and alumina cement (6) Phenol resin and coal tar pitch As a result of detailed study of the binder suitable for spinel refractories, the inventor found that the chemical composition of the aggregate was
MgO 70-95 parts by weight, Al 2 O 3 5-25 parts by weight, CaO 0.1
~5 parts by weight, the remainder being 1 part by weight or less of SiO 2 ,
When Fe 2 O 3 , B 2 O 3 , etc. are in the range, condensed alkali phosphates exhibit extremely excellent properties, and unfired refractories having performance equivalent to refractories fired at high temperatures can be obtained. I found out. The superiority of alkali condensed phosphates compared to other binders can be seen everywhere, but for example, in comparison with magnesium salts in (1),
It has significantly superior strength in the temperature range of 800℃ to 1400℃, and compared to (2), (3), and (5) silica-based binders and cements, it has improved volumetric stability and stability during use when heated and cooled. Excellent in terms of resistance to spalling, etc. In particular, volumetric stability during heating and cooling has traditionally been cited as a drawback of unfired refractories, and is extremely important in preventing joint wear and partial falling off of refractories. Needless to say, the advantage of (6) over the carbonaceous binder is that the strength does not deteriorate in an oxidizing atmosphere. The present invention uses such alkali condensed phosphates, and the amount used is preferably 1 to 4 parts by weight per 100 parts by weight of aggregate. If it is less than 1 part by weight, it is not sufficient to satisfy the strength of the unfired refractory, and if it is more than 4 parts by weight, the amount of the binder, which has poor heat resistance, increases more than necessary, and the sintering during use of the refractory increases. Since this phenomenon is accelerated, the volume stability during heating and cooling and the resistance to thermal spalling are significantly deteriorated, which is undesirable. In addition, other than condensed alkali phosphates, such as the above-mentioned (1) to (3) and
The combination of binders such as (5) and (6) is limited to the range where condensed alkali phosphates are the main binder, specifically water,
It can be used in an amount that does not exceed the weight percent of the alkali condensed phosphates in terms of the solid content of the binder from which the solvent has been removed. Specifically, the condensed alkali phosphates used in the present invention have a molar ratio of R 2 O/P 2 O 5 of 1.5/
It is limited to those having a composition range of 1 to 1/1, but this includes those containing more R 2 O than the R 2 O/P 2 O 5 molar ratio of 1.5/1, i.e., sodium pyrophosphate, sodium tripolyphosphate. , potassium pyrophosphate, potassium tripolyphosphate, etc., have a high chemical bonding rate with magnesia and spinel raw materials, causing problems in the refractory manufacturing process and at the same time increasing the alkali component that causes heat resistance deterioration. Undesirable. Also R 2 O/P 2 O 5
Ultra polyphosphate has a molar ratio of less than 1/1 and has less alkaline components, that is, the pH of ultra polyphosphate is in a fairly acidic range, so the reaction with basic raw materials occurs extremely quickly, and it is used as a binder for unfired refractories. It is inappropriate as such. Due to the above-mentioned restrictions, binders that can be used in the present invention include sodium tetrapolyphosphate, sodium pentapolyphosphate, sodium hexametaphosphate, potassium tetrapolyphosphate, potassium metaphosphate, etc., but are not necessarily limited to these. However, any material having the above-mentioned R 2 O/P 2 O 5 molar ratio can be used. The present invention uses condensed alkali phosphates having such a composition range, but in order to improve the performance of unfired refractories as much as possible, it is necessary to adjust the chemical composition of the aggregate used within a certain range. Specifically, 70 to 95 parts by weight of MgO, 5 to 25 parts by weight of Al 2 O 3
It must be composed of SiO 2 , Fe 2 O 3 , B 2 O 3 and the like in an amount of 0.1 to 5 parts by weight of CaO, and a balance of 1 part by weight or less each. Here, in a range where Al 2 O 3 is less than 5 parts by weight, that is, less than about 7 parts by weight in terms of MgO Al 2 O 3 spinel, the resistance to thermal spalling, which is a characteristic of spinel refractories, is significantly reduced. It deteriorates and has properties similar to magnesia refractories, which is undesirable. In addition, in the range where Al 2 O 3 exceeds 25 parts by weight, the amount is about 35 parts by weight or more in terms of MgO・Al 2 O 3 , and since this spinel is difficult to sinter, it can cause significant strength deterioration during use as an unsintered refractory. This is unsuitable as it may cause the tissue to become compromised. CaO is contained in a considerable amount in basic raw materials, and its moderate presence is effective in raising the melting point of the silicate composition in the raw materials, and is particularly effective in improving hot strength in unfired refractories. However, since Al 2 O 3 coexists in the spinel refractories of the present invention, excessive presence of CaO produces, for example, calcium aluminate with a low melting point, which deteriorates hot properties, volume stability, etc. Because it deteriorates
The amount needs to be regulated to 5 parts by weight or less, preferably 3 parts by weight or less. Regarding the lower limit,
Although there are no particular restrictions, it is impossible to reduce the amount to 0.1 part by weight or less due to the characteristics of the raw materials. The amount of impurities including SiO 2 is extremely important in terms of volumetric stability, heat resistance, resistance to thermal spalling, etc. during use of the unfired spinel refractories of the present invention. Impurities other than SiO 2 contained in general basic raw materials are trace amounts and are unlikely to cause any harm.
As for SiO 2 , if the amount exceeds 1 part by weight, the performance of the refractory of the present invention using condensed alkali phosphates will be significantly deteriorated, so the use of such aggregate is inappropriate. Aggregates used in the present invention under conditions limited to the above chemical composition range include sintered magnesia, fused magnesia, and various chemical compositions, including MgO, MgO,
Mention may be made of spinels of Al 2 O 3 and sintered, fused spinels of MgO or Al 2 O 3 . High-purity alumina raw materials can be used to generate spinel during use of unfired refractories, but since this reaction is an expansion reaction, the addition of temperature may cause structural deterioration of the refractories during use. This is not desirable because it causes Furthermore, chromium oxide does not have any adverse effect on the unfired refractories of the present invention and can be used exceptionally, but chromium ores containing large amounts of silicate and iron oxide are within the chemical composition range of the present invention. limited to. Examples are shown below to explain in detail the unfired refractories according to the present invention. Example 1 Unfired refractories were manufactured using sintered magnesia and sintered spinel clinker as aggregates and varying their ratios. Most of the spinel clinkers are
It is made of MgO.Al 2 O 3 spinel and contains a small amount of free MgO. Commercially available sodium hexametaphosphate (Na 2 O: 30.6% by weight,
P 2 O 5 (69.0% by weight) was used in an outer layer of 2%, kneaded and molded by a known method, and then dried at 170° C. for 10 hours. To know the state during use, that is, the state after receiving heat
The samples were fired at 1600°C for 6 hours, and the quality and resistance to thermal spalling of the fired samples were investigated. The chemical composition of the manufactured unfired refractory (excluding the binder component) is shown in Table 1, and the physical property values of the unfired refractory and the physical property values after firing are shown in Table 2. Note that Example 1
-4 only uses 3 parts by weight of sintered alumina. In a range where alumina (spinel) is less than the range of the present invention, the volume stability and spalling resistance after firing are significantly deteriorated, and in a range where the content is higher than the range of the present invention, strength deterioration after firing is noticeable, which is within the scope of the present invention. The excellence of unfired refractories has been proven.
【表】【table】
【表】
実施例 ２
焼結マグネシア、電融スピネルクリンカーを配
合し、第３表の化学組成を有する骨材を調整し
た。これに本発明による結合剤を使用し、不焼成
耐火物を製造した。この特性及び実施例１と同様
な焼成後の物性を第４表に示した。[Table] Example 2 Sintered magnesia and fused spinel clinker were blended to prepare aggregate having the chemical composition shown in Table 3. The binder according to the present invention was used thereto to produce an unfired refractory. This characteristic and the physical properties after firing similar to those in Example 1 are shown in Table 4.
【表】【table】
【表】【table】
【表】【table】
【表】
実施例 ３
骨材に種々の焼結マグネシアクリンカーを使用
し、実施例１と同じ焼成スピネルを20重量部用い
て不焼成耐火物を製造した。この化学組成を第５
表に、品質を第６表に示した。[Table] Example 3 Unfired refractories were manufactured using various sintered magnesia clinkers as aggregates and 20 parts by weight of the same fired spinel as in Example 1. This chemical composition is the fifth
The quality is shown in Table 6.
【表】
なお、ここでは結合剤として実施例２で使用し
たと同じ縮合りん酸ナトリウムを骨材100重量に
対し２重量部使用した。（化学組成中には含まれ
ていない実施例１及び２と同様、本発明による不
焼成れんがは比較例に比べ良好な性状を有してい
る。かかる不焼成スピネル耐火物は従来焼成耐火
物が使用されたいた各種工業炉に適用可能であ
り、焼成耐火物と同等の実績を期待することがで
きる。[Table] Here, 2 parts by weight of condensed sodium phosphate, the same as that used in Example 2, was used as a binder per 100 weight of aggregate. (Similar to Examples 1 and 2, which are not included in the chemical composition, the unfired bricks according to the present invention have better properties than the comparative examples. Such unfired spinel refractories are different from the conventional fired refractories. It can be applied to various industrial furnaces that have been used, and can be expected to have the same performance as fired refractories.
【表】【table】
【表】【table】
Claims (1)
CaO0.1〜５重量部、残部が各々１重量部以下の
SiO2、Fe2O3、B2O3等から成る粒度調整された一
種以上の骨材と、R2O／P2O5モル比1.5／１〜
１／１の組成比を有する縮合りん酸アルカリ類か
ら成る結合剤とより成ることを特徴とする不焼成
耐火物。1 MgO 70-95 parts by weight, Al 2 O 3 5-25 parts by weight,
0.1 to 5 parts by weight of CaO, the remainder being 1 part by weight or less each
One or more types of aggregates with adjusted particle size consisting of SiO 2 , Fe 2 O 3 , B 2 O 3 etc. and R 2 O / P 2 O 5 molar ratio 1.5/1 ~
An unfired refractory comprising a binder comprising a condensed alkali phosphate having a composition ratio of 1/1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP55147376A JPS5771862A (en) | 1980-10-20 | 1980-10-20 | Non-baked refractories |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP55147376A JPS5771862A (en) | 1980-10-20 | 1980-10-20 | Non-baked refractories |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5771862A JPS5771862A (en) | 1982-05-04 |
| JPS6128622B2 true JPS6128622B2 (en) | 1986-07-01 |
Family
ID=15428829
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP55147376A Granted JPS5771862A (en) | 1980-10-20 | 1980-10-20 | Non-baked refractories |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5771862A (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5435208A (en) * | 1977-08-24 | 1979-03-15 | Ono Pharmaceut Co Ltd | Stabilization of prostaglandin and prostaglandin-ramily compound |
-
1980
- 1980-10-20 JP JP55147376A patent/JPS5771862A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5435208A (en) * | 1977-08-24 | 1979-03-15 | Ono Pharmaceut Co Ltd | Stabilization of prostaglandin and prostaglandin-ramily compound |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5771862A (en) | 1982-05-04 |
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