JPS6236985B2 - - Google Patents
Info
- Publication number
- JPS6236985B2 JPS6236985B2 JP55062090A JP6209080A JPS6236985B2 JP S6236985 B2 JPS6236985 B2 JP S6236985B2 JP 55062090 A JP55062090 A JP 55062090A JP 6209080 A JP6209080 A JP 6209080A JP S6236985 B2 JPS6236985 B2 JP S6236985B2
- Authority
- JP
- Japan
- Prior art keywords
- sio
- sintered body
- refractories
- cristobalite
- silica
- 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
Links
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 20
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 8
- 239000000377 silicon dioxide Substances 0.000 claims description 7
- 238000004519 manufacturing process Methods 0.000 claims description 4
- 239000000203 mixture Substances 0.000 claims description 4
- 238000010304 firing Methods 0.000 claims description 3
- 229910000423 chromium oxide Inorganic materials 0.000 claims 2
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 claims 1
- 239000000843 powder Substances 0.000 claims 1
- 239000011651 chromium Substances 0.000 description 25
- 229910004298 SiO 2 Inorganic materials 0.000 description 15
- 239000011819 refractory material Substances 0.000 description 10
- 239000011812 mixed powder Substances 0.000 description 6
- 229910052906 cristobalite Inorganic materials 0.000 description 5
- 230000035939 shock Effects 0.000 description 5
- 239000002893 slag Substances 0.000 description 5
- 229910052799 carbon Inorganic materials 0.000 description 4
- QDOXWKRWXJOMAK-UHFFFAOYSA-N dichromium trioxide Chemical compound O=[Cr]O[Cr]=O QDOXWKRWXJOMAK-UHFFFAOYSA-N 0.000 description 4
- 230000007797 corrosion Effects 0.000 description 3
- 238000005260 corrosion Methods 0.000 description 3
- 239000000155 melt Substances 0.000 description 3
- 238000005245 sintering Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 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
- 238000006243 chemical reaction Methods 0.000 description 2
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000001000 micrograph Methods 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 239000012071 phase Substances 0.000 description 2
- 238000001878 scanning electron micrograph Methods 0.000 description 2
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 230000005496 eutectics Effects 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000011152 fibreglass Substances 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 229910052573 porcelain Inorganic materials 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 230000001681 protective effect Effects 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
- 238000009628 steelmaking Methods 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 229910021493 α-cristobalite Inorganic materials 0.000 description 1
- 229910021494 β-cristobalite Inorganic materials 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B5/00—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture
- C03B5/16—Special features of the melting process; Auxiliary means specially adapted for glass-melting furnaces
- C03B5/42—Details of construction of furnace walls, e.g. to prevent corrosion; Use of materials for furnace walls
- C03B5/43—Use of materials for furnace walls, e.g. fire-bricks
Description
【発明の詳細な説明】
本発明は緻密に焼結されたシリカ（SiO2）−酸
化クロム（Cr2O3）系耐火物の製造法に関するも
のである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a densely sintered silica (SiO 2 )-chromium oxide (Cr 2 O 3 )-based refractory.
珪石耐火物は、約600℃以上からの熱膨張係数
が極めて小さく、耐熱衝撃抵抗性に優れまた高温
強度も大きい。しかし酸性スラグ以外の各種スラ
グ融液に対する耐侵食性は比較的小さい。 Silica stone refractories have an extremely small coefficient of thermal expansion above about 600°C, excellent thermal shock resistance, and high high-temperature strength. However, the corrosion resistance against various slag melts other than acid slag is relatively low.
一方Cr2O3を主成分とするクロミア質耐火物は
他の多くの耐火物に比較して各種スラグ融液に対
する耐侵食性では最つとも優れたものの一つであ
る。しかし熱膨張率が大きいことなどのために耐
熱衝撃抵抗性に劣る。 On the other hand, chromia refractories containing Cr 2 O 3 as a main component have one of the best corrosion resistances against various slag melts compared to many other refractories. However, it has poor thermal shock resistance due to its large coefficient of thermal expansion.
上述の珪石耐火物の欠点はCr2O3の添加によつ
て解決されることが、特に酸化鉄を主体とするス
ラグに対する耐食性には効果のあることが相平衡
に関する研究から明らかにされている。一方クロ
ミア質耐火物の耐熱衝撃抵抗性に劣る欠点は高温
における低熱膨張性のシリカを混合することによ
つて解決されることが考えられる。したがつて両
者の混合物の緻密な構造体を作ることができれ
ば、すぐれた耐火物になりうることが推察でき
る。 Studies on phase equilibrium have shown that the above-mentioned drawbacks of silica refractories can be solved by adding Cr 2 O 3 , which is particularly effective in corrosion resistance against slag, which is mainly composed of iron oxide. . On the other hand, it is thought that the disadvantage of poor thermal shock resistance of chromia refractories can be solved by incorporating silica, which has low thermal expansion at high temperatures. Therefore, it can be inferred that if a dense structure can be made from a mixture of the two, it can be made into an excellent refractory.
しかしながら、SiO2とCr2O3とは化合物を作ら
ず、共融点はSiO2の融点（1723℃）よりわずか
に低い1720℃であり、また高温での焼結では
Cr2O3の蒸発などによつて、従来SiO2とCr2O3の
２成分のみからなる成形体を緻密に焼結すること
は困難であり、製造されていない。 However, SiO 2 and Cr 2 O 3 do not form a compound, their eutectic point is 1720°C, which is slightly lower than the melting point of SiO 2 (1723°C), and they do not form a compound when sintered at high temperatures.
Conventionally, it has been difficult to densely sinter a molded body consisting of only two components, SiO 2 and Cr 2 O 3 , by evaporation of Cr 2 O 3 , and so it has not been manufactured.
本発明者はさきに、Cr2O3単味の成形体を炭素
粉末中で焼成することにより、緻密に焼結し得る
ことを開発した（特開昭54−96508号公報）。更に
これに間する研究を進め、SiO2とCr2O3との混合
粉末成形体の焼結に発展させた。すなわち、熱力
学的平衡関係からみて、SiO2は炭素粉末中では
約1550℃以下の温度で安定であり、またCr2O3と
全く反応しない。そのため、Cr2O3単味の場合の
1400〜1500℃における炭素粉末中での焼成で
Cr2O3粒子表面における不安定相の形成による焼
結機構を利用してSiO2とCr2O3との混合粉末成形
体の緻密化焼結が可能となるかもしれないことを
考察した。この考察に基づいて実験を進めたとこ
ろ、これが実証され、クリストバライト粒と
Cr2O3粒とからなる緻密な焼結体を得ることがで
きた。そしてこの焼結体の耐火物は、従来珪石耐
火物およびクロミア耐火物のそれぞれの欠点を補
強したような耐火物となることを知見した。 The present inventor has previously developed that it is possible to sinter densely by firing a compact of Cr 2 O 3 in carbon powder (Japanese Patent Laid-Open No. 54-96508). Further research was carried out and developed into the sintering of a mixed powder compact of SiO 2 and Cr 2 O 3 . That is, in terms of thermodynamic equilibrium, SiO 2 is stable in carbon powder at temperatures below about 1550° C., and does not react with Cr 2 O 3 at all. Therefore, in the case of Cr 2 O 3 monotony,
By calcination in carbon powder at 1400-1500℃
We considered that it might be possible to densify a mixed powder compact of SiO 2 and Cr 2 O 3 by utilizing the sintering mechanism based on the formation of an unstable phase on the surface of Cr 2 O 3 particles. When we conducted experiments based on this consideration, we verified this and found that cristobalite grains and
A dense sintered body consisting of three Cr 2 O grains could be obtained. It was also discovered that the refractory of this sintered body is a refractory that reinforces the drawbacks of conventional silica refractories and chromia refractories.
すなわち、SiO2とCr2O3との任意の比率の混合
粉末成形体から得られた焼結体は、５％以下の気
孔率であり（図−１）、また耐化学的侵食性に優
れそしてスラグなどの融液にぬれにくいCr2O3が
SiO2粒周囲に存在するため（図−２）、従来の珪
石耐火物と比較して耐化学的侵食性を著しく向上
させるものであつた。しかもこの耐火物は他成分
の添加もなく、SiO2とCr2O3のみを緻密に焼結し
たものであるために1720℃まで液相を生成するこ
とがなく、そのため熱間強度も高くこの温度まで
安全に使用できる。一方クロミア質耐火物からみ
れば、約300℃以上からの熱膨張率はSiO2の混合
量の増加と共に低くなり（図−４、図−５）、膨
張率の大きさから生ずる耐熱衝撃抵抗性に劣る欠
点は大きく改良された。 In other words, a sintered body obtained from a mixed powder compact of SiO 2 and Cr 2 O 3 in any ratio has a porosity of 5% or less (Figure 1) and has excellent chemical attack resistance. Cr 2 O 3 is difficult to wet with melts such as slag.
Because it exists around two SiO grains (Figure 2), it significantly improves chemical attack resistance compared to conventional silica refractories. Moreover, this refractory does not contain any other ingredients and is made by densely sintering only SiO 2 and Cr 2 O 3 , so it does not form a liquid phase up to 1720℃, and therefore has high hot strength. Safe to use up to temperature. On the other hand, from the perspective of chromia refractories, the coefficient of thermal expansion at temperatures above about 300℃ decreases as the amount of SiO 2 mixed increases (Fig. 4, Fig. 5), and the thermal shock resistance caused by the large coefficient of expansion decreases. Its disadvantages have been greatly improved.
さらにこの耐火物の製造は、1400〜1500℃程度
の温度でよく、また炭素中で焼成するため、適当
な容器中に入れることによつて一般に使用されて
いる窯炉を用いて焼成でき特殊な炉を必要としな
いため低コストで製造できる。 Furthermore, this refractory can be manufactured at a temperature of about 1,400 to 1,500℃, and since it is fired in carbon, it can be fired in a commonly used kiln by placing it in an appropriate container. Since it does not require a furnace, it can be manufactured at low cost.
このように本発明は、物性の優れた高品質の耐
火物を低コストで製造することを可能にしたもの
であり、長繊維ガラス製造用炉材として、製鋼炉
用炉材としてなど多大の利益を与えるものであ
る。 In this way, the present invention has made it possible to manufacture high-quality refractories with excellent physical properties at low cost, and has great benefits such as as a furnace material for producing long fiber glass and as a furnace material for steelmaking furnaces. It gives
さらにこの焼結体は、緻密に焼結されており、
耐化学的侵食性に極めて優れまた耐熱衝撃抵抗性
に比較的優れたものであるため、坩堝や保護管な
どの特殊磁器への用途も考えられる。 Furthermore, this sintered body is densely sintered,
Since it has extremely high chemical attack resistance and relatively high thermal shock resistance, it can also be used for special porcelain such as crucibles and protective tubes.
以下この焼結体の製造法を実施例をもつて更に
詳細に説明する。 The method for manufacturing this sintered body will be explained in more detail below using examples.
実施例
無水ケイ酸（沈降製）試薬とCr2O3試薬とを
種々の割合に混合し、、この混合粉末を広さ45×
27mmの金型で厚さ15〜10mmの板状に800Kg／cm2の
圧力でプレス成形した。これをアルミナ容器に入
れ、成形体周囲に炭素粉末を十分充填し蓋をし
た。そしてこのアルミナ容器を電気炉に入れ、
1500℃で２時間焼成した。焼成された試料周囲に
は0.1〜1.5mmの炭素との反応層が形成され、やや
気孔の多い層となり、クリストバライトに富んだ
層となつていた。この反応層を除去した後に嵩密
度を測定し、それより気孔率を求めると、図−１
に示されるように、ほぼ全組成範囲で５％以下の
気孔率であつた。そしてこの焼結体のＸ線分析で
は、クリストバライト、Cr2O3および微量のCr2
（Ｃ、Ｎ）から構成されていた。その微構造の１
例をSiO2が40重量％、Cr2O3が60重量％の試料の
ものについて示すと、図−２の反射顕微鏡写真の
ように、クリストバライト粒とCr2O3粒とが均一
に、しかもそれは図−３の破断面の走査電顕写真
で示されるように緻密に焼結されていた。そして
焼結体の膨張曲線は図−４で示されるように、
220〜280℃でα−クリストバライトからβ−クリ
ストバライトへの転移による異常膨張があるもの
の、しかしそれ以上の温度ではほぼ直線的に膨張
し、膨張率は図−５のようにSiO2の混合割合の
多いものほど低くなつていた。Example Anhydrous silicic acid (manufactured by Precipitation) reagent and Cr 2 O 3 reagent were mixed in various proportions, and the mixed powder was spread into a 45×
It was press-molded into a plate shape with a thickness of 15 to 10 mm using a 27 mm mold at a pressure of 800 kg/cm 2 . This was placed in an alumina container, the periphery of the compact was sufficiently filled with carbon powder, and the container was covered with a lid. Then, put this alumina container into an electric furnace,
It was baked at 1500°C for 2 hours. A 0.1-1.5 mm reaction layer with carbon was formed around the fired sample, resulting in a slightly porous layer rich in cristobalite. After removing this reaction layer, the bulk density was measured and the porosity was determined from it, as shown in Figure 1.
As shown, the porosity was 5% or less over almost the entire composition range. X-ray analysis of this sintered body revealed cristobalite, Cr 2 O 3 and a trace amount of Cr 2
It was composed of (C, N). Its microstructure 1
To give an example of a sample containing 40% by weight of SiO 2 and 60% by weight of Cr 2 O 3 , as shown in the reflection micrograph in Figure 2, cristobalite grains and 3 Cr 2 O grains are uniformly distributed. It was densely sintered as shown in the scanning electron micrograph of the fractured surface in Figure 3. The expansion curve of the sintered body is shown in Figure 4.
Although there is abnormal expansion due to the transition from α-cristobalite to β-cristobalite at 220 to 280°C, it expands almost linearly at higher temperatures, and the expansion rate changes with the mixing ratio of SiO 2 as shown in Figure 5. The more things there were, the lower they became.
図−１はSiO2とCr2O3との混合粉末成形体を
1500℃で２時間炭素粉末中で焼成して得られた焼
結体の嵩密度(A)、真空度(B)、および気孔率(C)を
SiO2とCr2O3との混合比に対して示したものであ
る。図−２はSiO2（40重量％）とCr2O3（60重量
％）との混合粉末成形体から作られた焼結体の研
摩面の反射顕微鏡写真であり、Ｓはクリストバラ
イト、ＥはCr2O3、ＮはCr2（Ｃ、Ｎ）を示す。
図−３は図−２と同じ焼結体の破断面の走査電顕
写真を示す。図−４は焼結体の熱膨張曲線であ
り、図−５は500〜1000℃における平均熱膨張係
数を組成比に対して示したものである。
Figure 1 shows a mixed powder compact of SiO 2 and Cr 2 O 3 .
The bulk density (A), degree of vacuum (B), and porosity (C) of the sintered body obtained by firing in carbon powder at 1500℃ for 2 hours are
This is shown for the mixing ratio of SiO 2 and Cr 2 O 3 . Figure 2 is a reflection micrograph of the polished surface of a sintered body made from a mixed powder compact of SiO 2 (40% by weight) and Cr 2 O 3 (60% by weight), where S is cristobalite and E is Cr 2 O 3 and N represent Cr 2 (C, N).
Figure 3 shows a scanning electron micrograph of the fractured surface of the same sintered body as in Figure 2. Figure 4 shows the thermal expansion curve of the sintered body, and Figure 5 shows the average thermal expansion coefficient at 500 to 1000°C versus composition ratio.
Claims (1)
成形体を炭素粉末中で焼成することを特徴とする
緻密質シリカ−酸化クロム系耐火物の製造法。1. A method for producing a dense silica-chromium oxide refractory, which comprises firing a powder compact made of a mixture of silica and chromium oxide in carbon powder.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6209080A JPS56160375A (en) | 1980-05-10 | 1980-05-10 | Manufacture of silica-chromium oxide refractories |
| US06/240,436 US4374897A (en) | 1980-03-04 | 1981-03-04 | Chromium oxide-based sintered bodies and process for production thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6209080A JPS56160375A (en) | 1980-05-10 | 1980-05-10 | Manufacture of silica-chromium oxide refractories |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS56160375A JPS56160375A (en) | 1981-12-10 |
| JPS6236985B2 true JPS6236985B2 (en) | 1987-08-10 |
Family
ID=13190002
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6209080A Granted JPS56160375A (en) | 1980-03-04 | 1980-05-10 | Manufacture of silica-chromium oxide refractories |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS56160375A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63319251A (en) * | 1987-06-22 | 1988-12-27 | Mitsubishi Heavy Ind Ltd | Production of chromium oxide-based dense sintered body |
-
1980
- 1980-05-10 JP JP6209080A patent/JPS56160375A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS56160375A (en) | 1981-12-10 |
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