JP6642596B2 - Graphite-containing castable refractories and method for producing graphite-containing castable refractories - Google Patents
Graphite-containing castable refractories and method for producing graphite-containing castable refractories Download PDFInfo
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims description 194
- 229910002804 graphite Inorganic materials 0.000 title claims description 183
- 239000010439 graphite Substances 0.000 title claims description 183
- 238000004519 manufacturing process Methods 0.000 title claims description 19
- 239000011819 refractory material Substances 0.000 title description 19
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 63
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 41
- 238000009832 plasma treatment Methods 0.000 claims description 30
- 238000000034 method Methods 0.000 claims description 26
- 229910052611 pyroxene Inorganic materials 0.000 claims description 17
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 16
- 239000012159 carrier gas Substances 0.000 claims description 13
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 12
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims description 12
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 12
- 239000001301 oxygen Substances 0.000 claims description 12
- 229910052760 oxygen Inorganic materials 0.000 claims description 12
- 239000004568 cement Substances 0.000 claims description 10
- 239000002270 dispersing agent Substances 0.000 claims description 9
- 239000003570 air Substances 0.000 claims description 8
- 239000001257 hydrogen Substances 0.000 claims description 8
- 229910052739 hydrogen Inorganic materials 0.000 claims description 8
- 238000002156 mixing Methods 0.000 claims description 8
- 229910052757 nitrogen Inorganic materials 0.000 claims description 8
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 claims description 8
- 229910052596 spinel Inorganic materials 0.000 claims description 8
- 239000011029 spinel Substances 0.000 claims description 8
- VXYADVIJALMOEQ-UHFFFAOYSA-K tris(lactato)aluminium Chemical compound CC(O)C(=O)O[Al](OC(=O)C(C)O)OC(=O)C(C)O VXYADVIJALMOEQ-UHFFFAOYSA-K 0.000 claims description 7
- 229910052786 argon Inorganic materials 0.000 claims description 6
- 239000001307 helium Substances 0.000 claims description 6
- 229910052734 helium Inorganic materials 0.000 claims description 6
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 claims description 6
- 239000000395 magnesium oxide Substances 0.000 claims description 6
- 229910052751 metal Inorganic materials 0.000 claims description 6
- 239000002184 metal Substances 0.000 claims description 6
- 229910010271 silicon carbide Inorganic materials 0.000 claims description 6
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims description 6
- 229910052782 aluminium Inorganic materials 0.000 claims description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 4
- 229910052580 B4C Inorganic materials 0.000 claims description 3
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 3
- INAHAJYZKVIDIZ-UHFFFAOYSA-N boron carbide Chemical compound B12B3B4C32B41 INAHAJYZKVIDIZ-UHFFFAOYSA-N 0.000 claims description 3
- 239000010703 silicon Substances 0.000 claims description 3
- 229910052710 silicon Inorganic materials 0.000 claims description 3
- 125000004435 hydrogen atom Chemical class [H]* 0.000 claims 1
- 230000000052 comparative effect Effects 0.000 description 46
- 238000010276 construction Methods 0.000 description 36
- 230000007797 corrosion Effects 0.000 description 34
- 238000005260 corrosion Methods 0.000 description 34
- 230000003628 erosive effect Effects 0.000 description 12
- 239000002893 slag Substances 0.000 description 12
- 239000002994 raw material Substances 0.000 description 11
- 229910052799 carbon Inorganic materials 0.000 description 10
- 239000006229 carbon black Substances 0.000 description 9
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 8
- 239000000203 mixture Substances 0.000 description 8
- 230000007423 decrease Effects 0.000 description 6
- 238000012545 processing Methods 0.000 description 6
- 239000011248 coating agent Substances 0.000 description 5
- 238000000576 coating method Methods 0.000 description 5
- 230000003247 decreasing effect Effects 0.000 description 5
- 239000007789 gas Substances 0.000 description 5
- 150000002431 hydrogen Chemical class 0.000 description 5
- 230000035515 penetration Effects 0.000 description 5
- 239000011148 porous material Substances 0.000 description 5
- 239000003795 chemical substances by application Substances 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 3
- 229910021383 artificial graphite Inorganic materials 0.000 description 3
- 238000011156 evaluation Methods 0.000 description 3
- 125000000524 functional group Chemical group 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 230000003204 osmotic effect Effects 0.000 description 3
- 238000004806 packaging method and process Methods 0.000 description 3
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005469 granulation Methods 0.000 description 2
- 230000003179 granulation Effects 0.000 description 2
- 230000002209 hydrophobic effect Effects 0.000 description 2
- JVTAAEKCZFNVCJ-UHFFFAOYSA-N lactic acid Chemical compound CC(O)C(O)=O JVTAAEKCZFNVCJ-UHFFFAOYSA-N 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000012299 nitrogen atmosphere Substances 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 235000019738 Limestone Nutrition 0.000 description 1
- 229920003171 Poly (ethylene oxide) Polymers 0.000 description 1
- 239000004721 Polyphenylene oxide Substances 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000003963 antioxidant agent Substances 0.000 description 1
- 230000003078 antioxidant effect Effects 0.000 description 1
- 239000012298 atmosphere Substances 0.000 description 1
- 239000011449 brick Substances 0.000 description 1
- 238000012790 confirmation Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 238000005087 graphitization Methods 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000008595 infiltration Effects 0.000 description 1
- 238000001764 infiltration Methods 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- 239000004310 lactic acid Substances 0.000 description 1
- 235000014655 lactic acid Nutrition 0.000 description 1
- 239000006028 limestone Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 239000012768 molten material Substances 0.000 description 1
- PSZYNBSKGUBXEH-UHFFFAOYSA-N naphthalene-1-sulfonic acid Chemical compound C1=CC=C2C(S(=O)(=O)O)=CC=CC2=C1 PSZYNBSKGUBXEH-UHFFFAOYSA-N 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000008188 pellet Substances 0.000 description 1
- 229920000570 polyether Polymers 0.000 description 1
- -1 polyoxyethylene Polymers 0.000 description 1
- 229910052903 pyrophyllite Inorganic materials 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
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- Carbon And Carbon Compounds (AREA)
- Furnace Housings, Linings, Walls, And Ceilings (AREA)
Description
本発明は、製鉄所内で使用される黒鉛含有キャスタブル耐火物および黒鉛含有キャスタブル耐火物の製造方法に関する。 The present invention relates to a graphite-containing castable refractory used in an ironworks and a method for producing the graphite-containing castable refractory.
近年、製鉄所で使用される耐火物に占める不定形耐火物の比率が増大している。不定形耐火物の１つであるキャスタブル耐火物は、酸化物のみで構成される場合が多い。その理由としては、水を用いて混練するので、疎水性を有する炭化物やカーボン源などを使用すると、混水量が多くなり、施工体の強度が小さくなったり、見かけ気孔率が大きくなるからである。 In recent years, the ratio of irregular-shaped refractories to refractories used in steelworks has been increasing. Castable refractories, one of the irregular refractories, are often composed of oxides only. The reason for this is that since water is used for kneading, if a carbide or carbon source having hydrophobicity is used, the amount of mixed water increases, the strength of the construction body decreases, or the apparent porosity increases. .
このような状況下、唯一、高炉樋材は、Ａｌ２Ｏ３−ＳｉＣ−Ｃ、ＳｉＣ−Ｃ質のキャスタブル耐火物となっているが、高炉樋材で使用されているカーボン源は、ピッチ、カーボンブラックである。ピッチは、残炭率が５０〜９０質量％となっており、使用時に加熱されて揮発成分がなくなったあとが気孔として残るので、見かけ気孔率の増大や耐食性の低下の原因になる。また、カーボンブラックは、粒子径が２０〜１２０ｎｍと極めて小さく、酸化しやすいという問題がある。これらの欠点は、定型れんがで使用されている黒鉛化度が高く、且つ、熱伝導率や耐酸化性に優れる鱗状黒鉛を用いることで解決できる。しかしながら、鱗状黒鉛は、疎水性が最も高く、水を用いて施工するキャスタブル耐火物には使用することが困難である。 Under these circumstances, the only blast furnace gutter material is castable refractory of Al 2 O 3 —SiC—C or SiC—C, but the carbon source used in the blast furnace gutter material is pitch, It is carbon black. The pitch has a residual carbon ratio of 50 to 90% by mass, and remains as pores after being heated during use to eliminate volatile components, thereby causing an increase in apparent porosity and a decrease in corrosion resistance. In addition, carbon black has a problem that the particle diameter is extremely small as 20 to 120 nm and is easily oxidized. These drawbacks can be solved by using flake graphite having a high degree of graphitization used in fixed bricks and having excellent thermal conductivity and oxidation resistance. However, scaly graphite has the highest hydrophobicity, and is difficult to use for castable refractories constructed using water.
この問題を解決するために、特許文献１には、カーボンブラックなどの親水性カーボンを黒鉛表面に分散状態で固着させて、黒鉛の親水性を向上させる技術が開示されている。特許文献２および特許文献３には、アルミナなどの酸化物小粒子を黒鉛表面に固着させて黒鉛の親水性を向上させる技術が開示されている。特許文献４には、親水性の界面活性剤で黒鉛表面を被覆することで、黒鉛の親水性を向上させる技術が開示されている。 In order to solve this problem, Patent Literature 1 discloses a technique for improving the hydrophilicity of graphite by fixing hydrophilic carbon such as carbon black on a graphite surface in a dispersed state. Patent Documents 2 and 3 disclose techniques for improving the hydrophilicity of graphite by fixing small oxide particles such as alumina on the graphite surface. Patent Document 4 discloses a technique for improving the hydrophilicity of graphite by coating the graphite surface with a hydrophilic surfactant.
また、特許文献５には、衝撃力及び／又は摩擦力で黒鉛を球形化処理する技術が開示されている。特許文献６には、人造黒鉛を用いる技術が開示されている。さらに、特許文献７には、酸化物と黒鉛を造粒してペレットにすることで、黒鉛の疎水性を低減させる技術が開示されている。 Patent Literature 5 discloses a technique for spheroidizing graphite using impact force and / or frictional force. Patent Document 6 discloses a technique using artificial graphite. Further, Patent Literature 7 discloses a technique for reducing the hydrophobicity of graphite by granulating an oxide and graphite into pellets.
特許文献１〜４に開示されたカーボンブラックやアルミナなどの酸化物で黒鉛表面を被覆する技術は、被覆物を非常に微細なものとする必要があり、製造コストが増加する。また、特許文献５、６に開示された球状化黒鉛または人造黒鉛を用いる技術は、黒鉛の表面性状の疎水性は鱗状黒鉛等と変わるものではなく、黒鉛の形状をアスペクト比１の球形にすることでスラリー化させるための混水量を鱗状黒鉛等と比べて低減できるという効果があるのみである。このため、黒鉛の親水性は十分ではなく、施工時の混水量を十分低減することができず、見かけ気孔率の増大による耐食性低下を解決できる技術にならない。 The technology disclosed in Patent Documents 1 to 4 for coating the graphite surface with an oxide such as carbon black or alumina requires a very fine coating, which increases the manufacturing cost. Further, in the technology using spheroidized graphite or artificial graphite disclosed in Patent Documents 5 and 6, the hydrophobicity of the surface properties of graphite is not different from that of scaly graphite or the like, and the graphite is formed into a spherical shape having an aspect ratio of 1. This only has the effect of reducing the amount of mixed water for making a slurry as compared with scale graphite or the like. For this reason, the hydrophilicity of graphite is not sufficient, the amount of water mixed during construction cannot be sufficiently reduced, and the technology cannot solve the decrease in corrosion resistance due to an increase in apparent porosity.
また、特許文献７に開示された酸化物と黒鉛を造粒する技術は、事前に造粒工程が必要となるので製造コストが増加する。さらに、キャスタブル耐火物として混合する際に造粒物の一部が解砕されるので、造粒したことによる効果が発現しない、という課題があった。本発明は、上記課題を鑑みてなされたものであり、その目的とするところは、製造コストの増加を抑制しつつ、施工後の耐火物の耐食性を向上できる黒鉛含有キャスタブル耐火物を提供することにある。 Further, the technology for granulating oxide and graphite disclosed in Patent Document 7 requires a granulation step in advance, so that the production cost increases. Furthermore, since a part of the granulated material is crushed when mixed as a castable refractory, there is a problem that the effect of the granulation is not exhibited. The present invention has been made in view of the above problems, and an object of the present invention is to provide a graphite-containing castable refractory capable of improving the corrosion resistance of a refractory after construction while suppressing an increase in manufacturing cost. It is in.
このような課題を解決するための本発明の特徴は、以下の通りである。
（１）表面が親水化された黒鉛を１．０質量％以上２０．０質量％以下の範囲内で含有する、黒鉛含有キャスタブル耐火物。
（２）前記黒鉛は、表面がプラズマ処理された黒鉛である、（１）に記載の黒鉛含有キャスタブル耐火物。
（３）前記黒鉛は、写真読み取り法により測定される水の接触角が６０°未満である、（１）または（２）に記載の黒鉛含有キャスタブル耐火物。
（４）表面がプラズマ処理された黒鉛と、アルミナ、マグネシア、スピネルおよび炭化珪素の１種以上と、金属アルミニウム、金属シリコンおよび炭化ホウ素の１種以上と、アルミナセメント、シリカゾル、アルミナゾル、塩基性乳酸アルミニウムおよびρ-アルミナの１種以上と、分散剤と、を混合する黒鉛含有キャスタブル耐火物の製造方法であって、前記プラズマ処理された黒鉛は、１．０質量％以上２０．０質量％以下の範囲内で混合される、黒鉛含有キャスタブル耐火物の製造方法。
（５）前記アルミナ、前記マグネシア、前記スピネルおよび前記炭化珪素の１種以上に加えて、さらにろう石を混合する、（４）に記載の黒鉛含有キャスタブル耐火物の製造方法。
（６）前記プラズマ処理は、キャリアガスとして酸素、大気、水素、窒素、アルゴンおよびヘリウムの１種以上を用いて実施される、（４）または（５）に記載の黒鉛含有キャスタブル耐火物の製造方法。
（７）前記黒鉛は、写真読み取り法により測定される水の接触角が６０°未満である、（４）から（６）の何れか１つに記載の黒鉛含有キャスタブル耐火物の製造方法。
（８）前記プラズマ処理された黒鉛は、真空中で保管された後に混合される、（４）から（７）の何れか１つに記載の黒鉛含有キャスタブル耐火物の製造方法。
（９）前記プラズマ処理された黒鉛は、水中で保管され、乾燥された後に混合される、（４）から（７）の何れか１つに記載の黒鉛含有キャスタブル耐火物の製造方法。
The features of the present invention for solving such a problem are as follows.
(1) A graphite-containing castable refractory containing a graphite whose surface is hydrophilized in a range of 1.0% by mass to 20.0% by mass.
(2) The graphite-containing castable refractory according to (1), wherein the graphite is graphite whose surface is plasma-treated.
(3) The graphite-containing castable refractory according to (1) or (2), wherein the graphite has a contact angle of water measured by a photograph reading method of less than 60 °.
(4) Surface-treated graphite, one or more of alumina, magnesia, spinel and silicon carbide, one or more of metal aluminum, metal silicon and boron carbide, alumina cement, silica sol, alumina sol, basic lactic acid A method for producing a graphite-containing castable refractory, comprising mixing at least one of aluminum and ρ-alumina with a dispersant, wherein the plasma-treated graphite is 1.0% by mass or more and 20.0% by mass or less. A method for producing a graphite-containing castable refractory, which is mixed within the range of
(5) The method for producing a graphite-containing castable refractory according to (4), further comprising mixing in addition to one or more of the alumina, the magnesia, the spinel, and the silicon carbide.
(6) The production of a graphite-containing castable refractory according to (4) or (5), wherein the plasma treatment is performed using one or more of oxygen, air, hydrogen, nitrogen, argon, and helium as a carrier gas. Method.
(7) The method for producing a castable refractory containing graphite according to any one of (4) to (6), wherein the graphite has a contact angle of water measured by a photograph reading method of less than 60 °.
(8) The method for producing a graphite-containing castable refractory according to any one of (4) to (7), wherein the plasma-treated graphite is mixed after being stored in a vacuum.
(9) The method for producing a graphite-containing castable refractory according to any one of (4) to (7), wherein the plasma-treated graphite is stored in water, dried, and then mixed.
本発明の黒鉛含有キャスタブル耐火物に含まれる黒鉛は、その表面自体が親水化されているので、コストの高い微細なカーボンブラックやアルミナ等で表面を被覆することなく親水化できる。そして、当該黒鉛を含有する黒鉛含有キャスタブル耐火物は、少ない混水量でスラリー化させて耐火物を施工できるので、施工後の耐火物の見かけ気孔率を低減させることができ、これにより、耐食性の向上が実現できる。 Since the surface itself of the graphite contained in the graphite-containing castable refractory of the present invention is hydrophilized, it can be hydrophilized without coating the surface with fine carbon black, alumina or the like which is expensive. Then, the graphite-containing castable refractory containing the graphite can be slurried with a small amount of mixed water to construct the refractory, so that the apparent porosity of the refractory after the construction can be reduced, thereby improving the corrosion resistance. Improvement can be realized.
本発明者らは、酸素、大気、水素、窒素、アルゴンおよびヘリウムの１種以上の気体をキャリアガスとして黒鉛をプラズマ処理することで黒鉛の表面自体を親水化でき、当該黒鉛をキャスタブル耐火物に用いることで、少ない混水量でスラリー化でき、耐火物を施工できることを見出した。さらに、発明者らは、混水量を低減させて施工することで施工後の耐火物の見かけ気孔率が低減し、これにより、耐火物の耐食性を向上できることを見出して本発明を完成させた。以下に、本発明の実施形態を通じて本発明を詳細に説明する。 The present inventors have made it possible to hydrophilize the surface of graphite by subjecting graphite to plasma treatment using at least one of oxygen, air, hydrogen, nitrogen, argon and helium as a carrier gas, and convert the graphite into a castable refractory. By using it, it was found that a slurry can be formed with a small amount of mixed water and a refractory can be constructed. Furthermore, the inventors have found that by reducing the amount of mixed water and performing the construction, the apparent porosity of the refractory after the construction is reduced, thereby improving the corrosion resistance of the refractory, and completed the present invention. Hereinafter, the present invention will be described in detail through embodiments of the present invention.
本実施形態に係る黒鉛含有キャスタブル耐火物は、表面が親水化された黒鉛を含有する。黒鉛表面の親水化は、例えば、黒鉛をプラズマ処理することで実現できる。ここでプラズマ処理とは、大気圧下または真空下において、高圧電源を用いて酸素等の気体を励起させ、黒鉛の表面に照射する処理をいう。このプラズマ処理により、黒鉛表面に、−ＯＨ基、−ＣＨ＝Ｏ基、−ＣＯＯＨ基などの親水性の官能基を生成でき、疎水性の黒鉛表面に親水性を付与できる。これにより、コストの高い微細なカーボンブラックやアルミナ等で表面を被覆することなく黒鉛の表面自体を親水化できる。 The graphite-containing castable refractory according to the present embodiment contains graphite whose surface is hydrophilized. Hydrophilization of the graphite surface can be realized, for example, by subjecting graphite to plasma treatment. Here, the plasma treatment refers to a treatment in which a gas such as oxygen is excited using a high-voltage power supply under atmospheric pressure or vacuum, and the surface of graphite is irradiated. By this plasma treatment, hydrophilic functional groups such as —OH groups, —CH ＝ O groups, and —COOH groups can be generated on the graphite surface, and hydrophilicity can be imparted to the hydrophobic graphite surface. Thereby, the surface itself of graphite can be made hydrophilic without coating the surface with fine carbon black, alumina or the like which is expensive.
黒鉛の真空プラズマ処理は、例えば、Ｓｕｒｆａｃｅ Ｔｒｅａｔ社製のＬＡ４００を用いて、黒鉛量：２５０ｇ、電力：１ｋＷ、黒鉛の撹拌スピード：４０ｒｐｍ、圧力：１００Ｐａ、キャリアガス：酸素、処理時間：５分以上、の処理条件で実施できる。なお、キャリアガスとして、酸素、大気、水素、窒素、アルゴンおよびヘリウムの１種以上の気体を用いてよい。例えば、酸素に代えて大気を用いる場合には、処理時間を１０分以上とすることが好ましい。このように、キャリアガスの種類に応じて、処理時間を適宜調整してよい。また、真空プラズマ処理でなく大気圧下でプラズマ処理を行ってもよい。プラズマ処理する黒鉛としては、鱗状黒鉛、人造黒鉛および土状黒鉛の１種以上を用いてよい。 The vacuum plasma treatment of graphite is performed using, for example, LA400 manufactured by Surface Treat Co., Ltd., the amount of graphite: 250 g, the power: 1 kW, the stirring speed of graphite: 40 rpm, the pressure: 100 Pa, the carrier gas: oxygen, and the processing time: 5 minutes or more. , Can be carried out under the following processing conditions. Note that as the carrier gas, one or more of oxygen, air, hydrogen, nitrogen, argon, and helium may be used. For example, when air is used instead of oxygen, the processing time is preferably set to 10 minutes or more. As described above, the processing time may be appropriately adjusted according to the type of the carrier gas. Further, plasma processing may be performed under atmospheric pressure instead of vacuum plasma processing. As the graphite to be plasma-treated, at least one of scale-like graphite, artificial graphite, and earthy graphite may be used.
黒鉛表面に生成された親水性の官能基は、大気中のＣＯ２により汚染され、黒鉛表面の親水性が低下するおそれがある。プラズマ処理してから１週間以内に黒鉛を使用する場合には問題がないが、それ以上の期間保管する場合には、プラズマ処理された黒鉛を水中で保管し、乾燥させた後にキャスタブル耐火物に使用することが好ましい。また、水中で保管することに代えて、プラズマ処理された黒鉛を真空中で保管してもよい。これにより、黒鉛表面に生成された親水性官能基が、大気中のＣＯ２に汚染されることを抑制でき、黒鉛表面の親水性を長期間維持できる。 The hydrophilic functional groups generated on the graphite surface may be contaminated by CO 2 in the atmosphere, and the hydrophilicity of the graphite surface may be reduced. There is no problem if graphite is used within one week after the plasma treatment, but if it is to be stored for a longer period of time, the plasma-treated graphite should be stored in water, dried and then castable refractory. It is preferred to use. Instead of storing in water, graphite that has been plasma-treated may be stored in a vacuum. This can prevent the hydrophilic functional groups generated on the graphite surface from being contaminated by atmospheric CO 2 , and can maintain the hydrophilicity of the graphite surface for a long period of time.
黒鉛の親水性は、写真読み取り法による水の接触角で評価する。写真読み取り法は、以下の手順で実施する。まず、平滑な板の上に１０ｍｍ×２０ｍｍの両面テープを貼り、両面テープ上に０．０３ｇの黒鉛を広げて貼り付ける。次に、黒鉛の表面に薬包紙をのせ、薬包紙を介して黒鉛の表面全体を１ｋＮで２０秒間加圧し、薬包紙の平滑な面で黒鉛の表面を平滑化する。次に、黒鉛の表面より高さ１０ｍｍの位置から、黒鉛の表面へスポイトで水を１滴（約０．０３ｇ）滴下する。黒鉛の表面に水滴がのった状態で側面から写真を撮影して水の接触角を測定する。 The hydrophilicity of graphite is evaluated by the contact angle of water by a photograph reading method. The photograph reading method is performed according to the following procedure. First, a 10 mm × 20 mm double-sided tape is stuck on a smooth plate, and 0.03 g of graphite is spread and stuck on the double-sided tape. Next, a packaging paper is placed on the surface of the graphite, and the entire surface of the graphite is pressurized at 1 kN for 20 seconds via the packaging paper to smooth the surface of the graphite on the smooth surface of the packaging paper. Next, one drop (approximately 0.03 g) of water is dropped on the surface of the graphite with a dropper from a position 10 mm above the surface of the graphite. A photograph is taken from the side with the water droplets on the surface of the graphite, and the contact angle of water is measured.
図１は、黒鉛の表面に水滴がのった状態を側面から撮影した写真である。図１（ａ）は、プラズマ処理された鱗状黒鉛１０の表面１６に水滴１２がのった状態の写真であり、図１（ｂ）は、プラズマ処理されていない鱗状黒鉛１１の表面１６に水滴１２がのった状態の写真である。本実施形態における水の接触角は、表面１６と水滴１２との交点から引いた水滴１２の接線１４と、表面１６とのなす水滴１２側の角度である。鱗状黒鉛１０は、プラズマ処理されており親水性が高いので、水滴１２と鱗状黒鉛１０との接触面積が広くなる。このため、図１（ａ）では、水滴１２の高さは低くなり、水の接触角が小さくなる。一方、鱗状黒鉛１１はプラズマ処理されておらず疎水性が高いので、水滴１２と鱗状黒鉛１１との接触面積が狭くなる。このため、図１（ｂ）では、水滴１２の高さは高くなり、水の接触角が大きくなる。本実施形態では黒鉛をプラズマ処理して、黒鉛の写真読み取り法による水の接触角を６０°未満にしている。黒鉛の写真読み取り法による水の接触角を６０°未満にし、黒鉛の親水性を向上させることで、当該黒鉛を含有するキャスタブル耐火物の施工時の混水量を少なくできる。 FIG. 1 is a photograph taken from the side of a state in which water droplets are placed on the surface of graphite. FIG. 1A is a photograph showing a state in which water droplets 12 are placed on the surface 16 of the plasma-processed flake graphite 10, and FIG. 1B is a photograph showing water droplets on the surface 16 of the non-plasma-processed flake graphite 11. It is a photograph in which 12 was put. The contact angle of water in the present embodiment is the angle between the surface 16 and the tangent line 14 of the water droplet 12 drawn from the intersection of the surface 16 and the water droplet 12. Since the scale-like graphite 10 is plasma-treated and has high hydrophilicity, the contact area between the water droplet 12 and the scale-like graphite 10 is increased. For this reason, in FIG. 1A, the height of the water droplet 12 is reduced, and the contact angle of water is reduced. On the other hand, since the scale-like graphite 11 is not subjected to the plasma treatment and has high hydrophobicity, the contact area between the water droplet 12 and the scale-like graphite 11 is reduced. For this reason, in FIG. 1B, the height of the water droplet 12 is increased, and the contact angle of water is increased. In the present embodiment, graphite is subjected to a plasma treatment so that the contact angle of water by the graphite reading method is less than 60 °. By making the contact angle of water by a graphite reading method less than 60 ° and improving the hydrophilicity of graphite, the amount of mixed water during construction of castable refractories containing the graphite can be reduced.
実際に、キャリアガスとして酸素を用いて、真空プラズマ処理を５分間行った０．５ｍｍ以下の鱗状黒鉛の写真読み取り法による水の接触角を測定したところ、４５．５°［図１（ａ）］であった。一方、プラズマ処理を行っていない０．５ｍｍ以下の鱗状黒鉛の写真読み取り法による水の接触角を測定したところ、１０５．５°［図１（ｂ）］であった。この結果から、黒鉛の親水性を写真読み取り法による水の接触角で評価できることがわかる。また、キャリアガスとして酸素を含有する気体を用いて、黒鉛をプラズマ処理することで、鱗状黒鉛の表面自体を親水化でき、写真読み取り法による水の接触角が６０°未満になることが確認された。 Actually, when a contact angle of water was measured by a photograph reading method of a scale graphite of 0.5 mm or less, which was subjected to a vacuum plasma treatment for 5 minutes using oxygen as a carrier gas, 45.5 ° [FIG. ]Met. On the other hand, the contact angle of water measured by a photograph reading method on a scale graphite of 0.5 mm or less without plasma treatment was 105.5 ° [FIG. 1 (b)]. From this result, it is understood that the hydrophilicity of graphite can be evaluated by the contact angle of water by a photograph reading method. In addition, by performing a plasma treatment on graphite using a gas containing oxygen as a carrier gas, the surface itself of the scale-like graphite can be hydrophilized, and it has been confirmed that the contact angle of water according to the photograph reading method is less than 60 °. Was.
また、キャリアガスとして大気、水素、窒素、アルゴン、ヘリウムおよび水素と窒素の１：１混合ガスを用いて、真空プラズマ処理を１０分間行った０．５ｍｍ以下の鱗状黒鉛の写真読み取り法による水の接触角を測定した。この結果を表１に示す。 In addition, using a 1: 1 mixed gas of air, hydrogen, nitrogen, argon, helium and hydrogen and nitrogen as a carrier gas, a vacuum plasma treatment was performed for 10 minutes. The contact angle was measured. Table 1 shows the results.
表１に示すように、キャリアガスとして大気、水素、窒素、アルゴン、ヘリウムおよび水素と窒素の１：１混合ガスを用いた場合であっても、鱗状黒鉛の写真読み取り法による水の接触角は低下し、鱗状黒鉛の表面自体を親水化できる。 As shown in Table 1, even when air, hydrogen, nitrogen, argon, helium, and a 1: 1 mixed gas of hydrogen and nitrogen are used as the carrier gas, the contact angle of water according to the photographic graphite reading method is as follows. The surface itself of the scaly graphite can be made hydrophilic.
また、黒鉛の親水性は、浸透重量法による接触角でも評価できる。粉体への液体の浸透速度は、下記（１）式であるＬｕｃａｓ−Ｗａｓｈｂｕｒｎ式で求めることができる。 Further, the hydrophilicity of graphite can also be evaluated by the contact angle by the osmotic weight method. The permeation speed of the liquid into the powder can be determined by the following Lucas-Washburn equation (1).
接触角θの測定は、（１）式の浸透高さｌを浸透重量Ｗに置き換えた（２）式を用いる。接触角θを測定する対象の黒鉛をカラムに充填し、カラム内に水を浸透させ、経過時間ｔに対する水の重量Ｗ２の変化を測定する。理想的には、経過時間ｔに対してＷ２をプロットすると直線的な関係になるので、当該直線の傾きと下記（２）式とから浸透角θを算出する。 The measurement of the contact angle θ uses the equation (2) in which the permeation height 1 in the equation (1) is replaced by the permeation weight W. The object of graphite measuring the contact angle θ was packed into a column, impregnated with water in the column to measure the change in weight W 2 of water to the elapsed time t. Ideally, since a linear relationship is plotted W 2 against the elapsed time t, to calculate the penetration angle θ from the slope and the following equation (2) of the straight line.
上記（２）式を用いて接触角θを算出するには、水の表面張力、水の粘度および黒鉛の毛管半径ｒを算出することが必要になる。黒鉛の毛管半径ｒは、表面張力γ、粘度ηおよび黒鉛との接触角θが既知の液体を用いて浸透重量法を実施し、（２）式より黒鉛の毛管半径ｒを算出する。黒鉛の毛管半径ｒを算出するために用いる液体は、例えば、イソプロピルアルコール（表面張力γ＝２０．８ｍＮ、粘度η＝２．３７ｍＰａ・Ｓ、比重ρ＝０．７８５０５、黒鉛との接触角θ≒０°）である。 In order to calculate the contact angle θ using the above equation (2), it is necessary to calculate the surface tension of water, the viscosity of water, and the capillary radius r of graphite. The capillary radius r of graphite is obtained by performing an osmotic weight method using a liquid having a known surface tension γ, viscosity η, and contact angle θ with graphite, and calculating the capillary radius r of graphite from equation (2). The liquid used to calculate the capillary radius r of graphite is, for example, isopropyl alcohol (surface tension γ = 20.8 mN, viscosity η = 2.37 mPa · S, specific gravity ρ = 0.85505, contact angle θ with graphite) 0 °).
キャリアガスとして酸素を用いて、真空プラズマ処理を５分間行った０．５ｍｍ以下の鱗状黒鉛の浸透重量法による接触角θは７５．９°であった。一方、プラズマ処理を行っていない０．５ｍｍ以下の鱗状黒鉛の浸透重量法による接触角θは８９．７°であった。この結果から、黒鉛の親水性を浸透重量法による接触角θで評価できることがわかる。 The contact angle θ by a permeation weight method of scale graphite of 0.5 mm or less subjected to vacuum plasma treatment for 5 minutes using oxygen as a carrier gas was 75.9 °. On the other hand, the contact angle θ of 0.5 mm or less scale graphite not subjected to the plasma treatment by a permeation weight method was 89.7 °. These results show that the hydrophilicity of graphite can be evaluated by the contact angle θ by the osmotic weight method.
本実施形態の黒鉛含有キャスタブル耐火物は、プラズマ処理により表面が親水化された黒鉛を、黒鉛含有キャスタブル耐火物の質量に対して１．０質量％以上２０．０質量％以下の範囲内で含有する。これにより、施工後の耐火物の耐食性を向上でき、また、スラグの浸透厚みを低減できる。一方、表面が親水化された黒鉛の含有量が１．０質量％未満になると、施工後の耐火物の耐食性が向上せず、スラグ浸透厚みも低減できない。また、表面が親水化された黒鉛の含有量が２０．０質量％を超えると、黒鉛含有キャスタブル耐火物中の微粉量が増加して、黒鉛含有キャスタブル耐火物の施工性が低下する。このため、施工時の混水量が増え、施工後の耐火物の見かけ気孔率が増加し、耐火物の耐食性が低下する。 The graphite-containing castable refractory of the present embodiment contains graphite whose surface has been hydrophilized by plasma treatment in a range of 1.0% by mass to 20.0% by mass based on the mass of the graphite-containing castable refractory. I do. Thereby, the corrosion resistance of the refractory after construction can be improved, and the permeation thickness of the slag can be reduced. On the other hand, when the content of the graphite whose surface is hydrophilized is less than 1.0% by mass, the corrosion resistance of the refractory after construction is not improved, and the slag penetration thickness cannot be reduced. When the content of the graphite whose surface is hydrophilized exceeds 20.0% by mass, the amount of fine powder in the graphite-containing castable refractory increases, and the workability of the graphite-containing castable refractory decreases. For this reason, the amount of water mixture during construction increases, the apparent porosity of the refractory after construction increases, and the corrosion resistance of the refractory decreases.
また、表面が親水化された黒鉛以外のキャスタブル耐火物原料としては、骨材として、アルミナ、マグネシア、スピネルおよび炭化珪素の１種以上と、酸化防止剤として、金属アルミニウム、金属シリコンおよび炭化ホウ素の１種以上と、硬化剤として、アルミナセメント、シリカゾル、アルミナゾル、塩基性乳酸アルミニウムおよびρ−アルミナの１種以上と、分散剤として、カルボキシル基含有ポリエーテル系分散剤、ポリオキシエチレン系分散剤、ポリアクリル系分散剤、ナフタリンスルホン酸系分散剤、ポリカルボン酸系分散剤の１種または２種を用いてよい。分散剤は、キャスタブル耐火物原料に対して外掛けで０．０５質量％以上０．２０質量％以下の範囲内で添加される。これにより、キャスタブル耐火物原料を混合する際に各原料を均質に混合できる。 In addition, as a castable refractory raw material other than graphite whose surface is hydrophilized, one or more of alumina, magnesia, spinel, and silicon carbide are used as an aggregate, and as an antioxidant, metal aluminum, metal silicon, and boron carbide are used. At least one kind, as a hardening agent, at least one kind of alumina cement, silica sol, alumina sol, basic aluminum lactate and ρ-alumina, and as a dispersant, a carboxyl group-containing polyether-based dispersant, a polyoxyethylene-based dispersant, One or two of a polyacrylic dispersant, a naphthalenesulfonic acid dispersant, and a polycarboxylic acid dispersant may be used. The dispersant is added in a range of 0.05% by mass or more and 0.20% by mass or less with respect to the castable refractory raw material. Thereby, when mixing the castable refractory raw materials, the respective raw materials can be homogeneously mixed.
また、骨材であるアルミナ、マグネシア、スピネルおよび炭化珪素の１種以上に加え、ろう石を用いてもよい。ろう石はアルミナを含有する鉱物であるが、シリカも多く含有しており、耐火物としての性能は低下するが、耐火物の適用部位の温度条件や接触する溶融物等の環境条件が緩い場合には、十分に使用できる。ろう石を用いることで、キャスタブル耐火物原料コストを低減できる。なお、ろう石を用いる場合には、ろう石の含有量を３０質量％以下にすることが好ましい。これにより、キャスタブル耐火物の耐食性低下を抑制できる。これらキャスタブル耐火物原料に表面が親水化された黒鉛を１．０質量％以上２０．０質量％以下の範囲内で混合することで、少ない混水量で施工できる黒鉛含有キャスタブル耐火物にすることができる。そして、当該黒鉛含有キャスタブル耐火物を少ない混水量で施工することで、施工後の耐火物の見かけ気孔率を低減させることができ、これにより、耐火物の耐食性の向上が実現できる。 Further, in addition to one or more of the aggregates of alumina, magnesia, spinel, and silicon carbide, pyroxene may be used. Pyroxene is a mineral that contains alumina, but also contains a lot of silica, and its performance as a refractory decreases, but when the temperature conditions of the application site of the refractory or the environmental conditions such as the molten material that comes in contact are loose Can be used satisfactorily. By using the limestone, the cost of the raw material for castable refractories can be reduced. When using pyroxene, the content of pyroxene is preferably 30% by mass or less. Thereby, the corrosion resistance of the castable refractory can be suppressed from being reduced. By mixing the castable refractory raw material with a surface-hydrophilized graphite in a range of 1.0% by mass or more and 20.0% by mass or less, a graphite-containing castable refractory that can be constructed with a small amount of mixed water can be obtained. it can. Then, by constructing the graphite-containing castable refractory with a small amount of mixed water, the apparent porosity of the refractory after the construction can be reduced, thereby improving the corrosion resistance of the refractory.
次に、本発明の実施例１を説明する。０．５ｍｍ以下の鱗状黒鉛１２０ｇを、酸素をキャリアガスとして真空プラズマ処理を５分間実施した。これを２１回繰り返し実施して、約２．５ｋｇの表面が親水化された黒鉛を得た。表面が親水化された黒鉛またはプラズマ処理を行っていない黒鉛を用いて、スピネル−Ａｌ２Ｏ３−ＳｉＣ−Ｃキャスタブル耐火物を試作・評価した。試作条件および評価結果を表２、３に示す。 Next, a first embodiment of the present invention will be described. A vacuum plasma treatment of 120 g of 0.5 mm or less scale-like graphite was performed for 5 minutes using oxygen as a carrier gas. This was repeated 21 times to obtain about 2.5 kg of surface-hydrophilized graphite. Surface using a graphite not subjected to graphite or plasma treatment, which is hydrophilized, was fabricated and evaluated spinel -Al 2 O 3 -SiC-C castable refractory. Tables 2 and 3 show the conditions of the prototype and the evaluation results.
発明例１〜５は、プラズマ処理した黒鉛を１．０質量％以上２０．０質量％以下の範囲内で含むキャスタブル耐火物である。発明例５は、プラズマ処理した黒鉛を４．７質量％含み、骨材の一部にろう石を含むキャスタブル耐火物である。比較例１は、カーボン源としてピッチとカーボンブラックを合計で４．７質量％含むキャスタブル耐火物である。比較例２は、プラズマ処理を行っていない鱗状黒鉛を４．７質量％含むキャスタブル耐火物である。比較例３は、プラズマ処理した黒鉛を２５質量％含むキャスタブル耐火物である。比較例４は、カーボン源としてピッチとカーボンブラックを合計で４．７質量％含み、骨材の一部にろう石を含むキャスタブル耐火物である。比較例５は、プラズマ処理を行っていない鱗状黒鉛を４．７質量％含み、骨材の一部にろう石を含むキャスタブル耐火物である。 Inventive Examples 1 to 5 are castable refractories containing the graphite subjected to the plasma treatment in the range of 1.0% by mass to 20.0% by mass. Inventive Example 5 is a castable refractory containing 4.7% by mass of graphite subjected to plasma treatment and containing pyroxene as a part of aggregate. Comparative Example 1 is a castable refractory containing a total of 4.7% by mass of pitch and carbon black as carbon sources. Comparative Example 2 is a castable refractory containing 4.7% by mass of non-plasma-treated graphite graphite. Comparative Example 3 is a castable refractory containing 25% by mass of graphite subjected to plasma treatment. Comparative Example 4 is a castable refractory that includes a total of 4.7% by mass of pitch and carbon black as a carbon source, and contains pyroxene as a part of the aggregate. Comparative Example 5 is a castable refractory containing 4.7% by mass of flake graphite not subjected to the plasma treatment and containing pyroxene as a part of the aggregate.
表２、３に示した原料の比率で、合計質量が２．５ｋｇになるように各原料を混合し、万能ミキサーで３分間混練した。これをφ５０ｍｍ×高さ１００ｍｍの円柱形状の型枠に流し込み、１４００℃×３時間の還元焼成を行って発明例１〜５および比較例１〜５の耐火物を作製した。その後、φ３０ｍｍ×高さ３０ｍｍの穴あけ加工を行い、加工した穴に下記表４に示した組成の高炉スラグを４５ｇ充填し、窒素雰囲気下で、１６００℃で３時間熱処理を行った。試料を冷却させた後、半分に切断して孔径が拡大した割合を測定した。耐食性は、比較例１の孔径が拡大した割合を１００とし、発明例１〜５、比較例２〜５の割合を比較例１の割合で規格化した溶損指数で評価した。なお、表２、３のアルミナの行に記載された「１ｍｍ−」の「−」は、１ｍｍ以下の大きさのアルミナを用いることを意味し、他の行においても「−」の意味は同じである。 The raw materials were mixed so that the total mass became 2.5 kg in the ratio of the raw materials shown in Tables 2 and 3, and the mixture was kneaded for 3 minutes with a universal mixer. This was poured into a cylindrical mold having a diameter of 50 mm and a height of 100 mm, and reduced and fired at 1400 ° C. for 3 hours to produce refractories of Invention Examples 1 to 5 and Comparative Examples 1 to 5. Thereafter, a hole having a diameter of 30 mm and a height of 30 mm was drilled, and the processed hole was filled with 45 g of blast furnace slag having the composition shown in Table 4 below, and heat-treated at 1600 ° C. for 3 hours in a nitrogen atmosphere. After allowing the sample to cool, it was cut in half and the percentage of increase in pore size was measured. Corrosion resistance was evaluated by the erosion index normalized to the ratio of Comparative Example 1 with the ratio of Comparative Examples 1 to 5 and Comparative Examples 2 to 5, with the ratio at which the pore diameter of Comparative Example 1 was increased as 100. In addition, "-" of "1 mm-" described in the alumina row of Tables 2 and 3 means that alumina having a size of 1 mm or less is used, and the meaning of "-" is the same in other rows. It is.
表２、３に示すように、発明例１〜４は、いずれも比較例１より溶損指数が小さくなり、施工後の耐火物の耐食性が向上した。一方、比較例２は、比較例１より溶損指数が大きくなり、施工後の耐火物の耐食性が低下した。比較例２は、発明例１と同じ量の黒鉛を含むキャスタブル耐火物であるが、黒鉛がプラズマ処理されておらず黒鉛の疎水性が高いので当該キャスタブル耐火物の施工性が悪化した。このため、施工時の混水量が増加し、施工後の耐火物の見かけ気孔率が高くなり、耐火物の耐食性が低下した。 As shown in Tables 2 and 3, in each of Invention Examples 1 to 4, the erosion index was smaller than Comparative Example 1, and the corrosion resistance of the refractory after construction was improved. On the other hand, in Comparative Example 2, the erosion index was larger than in Comparative Example 1, and the corrosion resistance of the refractory after construction was reduced. Comparative Example 2 is a castable refractory containing the same amount of graphite as Inventive Example 1, but the graphite was not plasma-treated and the graphite was highly hydrophobic, so that the workability of the castable refractory deteriorated. For this reason, the amount of water mixed during construction increased, the apparent porosity of the refractory after construction increased, and the corrosion resistance of the refractory decreased.
比較例３も比較例１より溶損指数が大きくなり、施工後の耐火物の耐食性が低下した。比較例３は、プラズマ処理された黒鉛を２５．０質量％で含有するキャスタブル耐火物であるが、キャスタブル耐火物中の黒鉛の微粉量が多くなりすぎ、当該キャスタブル耐火物の施工性が悪化した。このため、施工時の混水量が増加し、施工後の耐火物の見かけ気孔率が高くなり、施工後の耐火物の耐食性が低下した。 The erosion index of Comparative Example 3 was larger than that of Comparative Example 1, and the corrosion resistance of the refractory after construction was reduced. Comparative Example 3 is a castable refractory containing plasma-treated graphite at 25.0% by mass. However, the amount of fine graphite powder in the castable refractory became too large, and the workability of the castable refractory deteriorated. . For this reason, the amount of water mixed during construction increased, the apparent porosity of the refractory after construction increased, and the corrosion resistance of the refractory after construction decreased.
次に、骨材の一部にろう石を含むＡｌ２Ｏ３−ＳｉＣ−Ｃキャスタブル耐火物の評価結果を説明する。表２、３に示すように、発明例５は、骨材の一部にろう石を含むキャスタブル耐火物である。この場合であっても、プラズマ処理された黒鉛を含むことで、カーボン源としてピッチとカーボンブラックを含む比較例４およびプラズマ処理されていない黒鉛を含む比較例５よりも溶損指数が小さくなり、施工後の耐火物の耐食性が向上した。比較例４は、骨材の一部にろう石を含むキャスタブル耐火物であるが、骨材の一部にろう石を含まず、他の組成が比較例４に近い比較例１と同じ混水量で施工できたが、ろう石に含まれるＳｉＯ２成分により耐火物の耐食性は悪化した。また、比較例５は、骨材の一部にろう石を含むキャスタブル耐火物であるが、当該耐火物の施工には骨材の一部にろう石を含まず、他の組成が比較例５に近い比較例２と同等の混水量で施工できたが、耐火物の耐食性は比較例２より悪化した。 Next, the evaluation results of the Al 2 O 3 —SiC—C castable refractory containing pyroxene as a part of the aggregate will be described. As shown in Tables 2 and 3, Inventive Example 5 is a castable refractory containing pyroxene as a part of the aggregate. Even in this case, by including the plasma-treated graphite, the erosion index is smaller than that of Comparative Example 4 including the pitch and carbon black as the carbon source and Comparative Example 5 including the graphite not subjected to the plasma treatment, The corrosion resistance of the refractory after construction was improved. Comparative Example 4 is a castable refractory that contains pyroxene as a part of the aggregate, but does not include pyroxene as a part of the aggregate and has the same water mixing amount as Comparative Example 1 whose other composition is close to Comparative Example 4. However, the corrosion resistance of the refractory deteriorated due to the SiO 2 component contained in the pyrophyllite. Further, Comparative Example 5 is a castable refractory that includes pyroxene as a part of the aggregate. However, in the refractory construction, the aggregate does not include pyroxene as a part of the aggregate, and the other composition has a different composition. However, the corrosion resistance of the refractory was worse than that of Comparative Example 2.
このように、プラズマ処理された黒鉛を１．０質量％以上２０．０質量％以下の範囲内で混合することで、スピネル−Ａｌ２Ｏ３−ＳｉＣ−Ｃキャスタブル耐火物の施工性を向上できることが確認された。そして、スピネル−Ａｌ２Ｏ３−ＳｉＣ−Ｃキャスタブル耐火物を少ない混水量で施工することで、施工後の耐火物の耐食性を向上できることが確認された。 Thus, by mixing the plasma-treated graphite in a range of 1.0 mass% or more 20.0% by mass or less, you can improve the workability of the spinel -Al 2 O 3 -SiC-C castable Was confirmed. And it was confirmed that the corrosion resistance of the refractory after construction can be improved by constructing the spinel-Al 2 O 3 -SiC-C castable refractory with a small amount of mixed water.
また、骨材の一部にろう石を含むＡｌ２Ｏ３−ＳｉＣ−Ｃキャスタブル耐火物であっても、ろう石含有量が同じ条件で比較すれば、プラズマ処理された黒鉛を混合することで骨材の一部にろう石を含まない黒鉛含有キャスタブル耐火物と同様に施工性を向上でき、施工後の耐火物の耐食性を向上できることが確認された。 Further, even in the case of Al 2 O 3 —SiC—C castable refractories containing pyroxene as a part of the aggregate, if the pyroxene content is compared under the same conditions, it is possible to mix plasma-treated graphite. It was confirmed that the workability could be improved in the same manner as the graphite-containing castable refractory which does not contain pyroxene in part of the aggregate, and the corrosion resistance of the refractory after the construction could be improved.
次に、本発明の実施例２を説明する。実施例１と同じ条件で０．５ｍｍ以下の鱗状黒鉛を真空プラズマ処理し、約２．５ｋｇの表面が親水化された黒鉛を得た。表面が親水化された黒鉛または未処理の黒鉛を用いて、Ａｌ２Ｏ３−ＭｇＯ−Ｃキャスタブル耐火物を試作・評価した。試作条件および評価結果を表５、６に示す。 Next, a second embodiment of the present invention will be described. Under the same conditions as in Example 1, vacuum plasma treatment was performed on 0.5 mm or less scale-like graphite to obtain about 2.5 kg of surface-hydrophilic graphite. Surface using a hydrophilized graphite or untreated graphite was fabricated and evaluated Al 2 O 3 -MgO-C castable refractory. Tables 5 and 6 show the experimental conditions and the evaluation results.
発明例６〜９は、プラズマ処理した黒鉛を１．０質量％以上２０．０質量％以下の範囲内で含むキャスタブル耐火物である。発明例１０〜１３は、プラズマ処理した黒鉛を５．０質量％で含み、硬化剤であるアルミナセメントに代えてシリカゾル、アルミナゾル、塩基性乳酸アルミニウムまたはρ−アルミナを用いたキャスタブル耐火物である。 Inventive Examples 6 to 9 are castable refractories containing graphite treated with plasma in a range of 1.0% by mass to 20.0% by mass. Inventive Examples 10 to 13 are castable refractories containing 5.0% by mass of graphite subjected to plasma treatment and using silica sol, alumina sol, basic aluminum lactate or ρ-alumina instead of alumina cement as a curing agent.
比較例６は、カーボンを含まないキャスタブル耐火物である。比較例７は、プラズマ処理を行っていない鱗状黒鉛を５．０質量％含むキャスタブル耐火物である。比較例８は、プラズマ処理した黒鉛を２５．０質量％含むキャスタブル耐火物である。比較例９〜１２は、プラズマ処理を行っていない鱗状黒鉛を５．０質量％含み、硬化剤であるアルミナセメントに代えてシリカゾル、アルミナゾル、塩基性乳酸アルミニウムまたはρ−アルミナを用いたキャスタブル耐火物である。 Comparative Example 6 is a castable refractory containing no carbon. Comparative Example 7 is a castable refractory containing 5.0% by mass of flake graphite not subjected to the plasma treatment. Comparative Example 8 is a castable refractory containing 25.0% by mass of graphite subjected to plasma treatment. Comparative Examples 9 to 12 were castable refractories containing 5.0% by mass of scale graphite not subjected to plasma treatment and using silica sol, alumina sol, basic aluminum lactate or ρ-alumina instead of alumina cement as a curing agent. It is.
表５、６に示した原料の比率で、合計質量が２．５ｋｇになるように各原料を混合し、万能ミキサーで３分間混練した。これをφ５０ｍｍ×高さ１００ｍｍの円柱形状の型枠に流し込み、比較例６のみ１４００℃で３時間の大気焼成を行い、他は１４００℃で３時間の還元焼成を行って発明例６〜１３および比較例６〜１２の耐火物を作製した。その後、φ３０ｍｍ×高さ３０ｍｍの穴あけ加工を行い、加工した穴に下記表７に示した組成の転炉スラグを４５ｇ充填し、窒素雰囲気下で、１６００℃で３時間熱処理を行った。試料を冷却させた後、半分に切断して孔径が拡大した割合を測定した。耐食性は、比較例６の孔径が拡大した割合を１００とし、発明例６〜１３、比較例６〜１２の割合を比較例６の割合で規格化した溶損指数で評価した。また、スラグ−耐火物界面からスラグが浸透した深さを測定し、当該深さをスラグ浸透厚み（ｍｍ）として評価した。スラグ浸透厚みが深くなると、スラグが浸透した部分とスラグが浸透していない部分の境界で耐火物の割れが発生するので、スラグ浸透厚みは浅いことが好ましい。なお、表５、６のアルミナの行に記載された「５ｍｍ−」の「−」は、５ｍｍ以下の大きさのアルミナを用いることを意味し、他の行においても「−」の意味は同じである。 The raw materials were mixed at the ratio of the raw materials shown in Tables 5 and 6 so that the total mass became 2.5 kg, and kneaded with a universal mixer for 3 minutes. This was poured into a cylindrical mold having a diameter of 50 mm and a height of 100 mm, and only Comparative Example 6 was fired in the air at 1400 ° C. for 3 hours, and the others were reduced and fired at 1400 ° C. for 3 hours to perform Invention Examples 6 to 13 and Refractories of Comparative Examples 6 to 12 were produced. Thereafter, a hole having a diameter of 30 mm and a height of 30 mm was drilled, and 45 g of converter slag having the composition shown in Table 7 below was filled in the formed hole, and heat treatment was performed at 1600 ° C. for 3 hours in a nitrogen atmosphere. After allowing the sample to cool, it was cut in half and the percentage of increase in pore size was measured. The corrosion resistance was evaluated by the erosion index normalized to the ratio of Comparative Example 6 with the ratio of Comparative Examples 6 to 13 and the ratio of Comparative Examples 6 to 12 assuming that the ratio of the pore diameter of Comparative Example 6 was 100. Further, the depth at which the slag permeated from the slag-refractory interface was measured, and the depth was evaluated as the slag permeation thickness (mm). If the slag infiltration depth is large, the refractory cracks at the boundary between the portion where the slag has penetrated and the portion where the slag has not penetrated. Therefore, the slag permeation thickness is preferably small. In addition, "-" of "5 mm-" described in the row of alumina in Tables 5 and 6 means that alumina having a size of 5 mm or less is used, and the meaning of "-" is the same in other rows. It is.
表５、６に示すように、発明例６〜９は、いずれも比較例６より混水量が多くなったものの、溶損指数が小さくなり、施工後の耐火物の耐食性は良好であった。発明例１０〜１３は、アルミナセメントに代えて、シリカゾル、アルミナゾル、塩基性乳酸アルミニウムまたはρ−アルミナを用いたキャスタブル耐火物であるので、原料に含まれるアルミナセメント由来のＣａＯが少ない。キャスタブル耐火物に含まれるＣａＯを少なくすることで耐火物の融点が高くなるので、施工後の耐火物の耐食性がさらに向上できる可能性がある。今回の確認では、発明例１１〜１３において、発明例６よりも溶損指数が小さくなり、耐食性が高くなった。 As shown in Tables 5 and 6, in each of Inventive Examples 6 to 9, although the amount of mixed water was larger than that of Comparative Example 6, the erosion index was small, and the corrosion resistance of the refractory after construction was good. Inventive Examples 10 to 13 are castable refractories using silica sol, alumina sol, basic aluminum lactate or ρ-alumina instead of alumina cement, so that CaO derived from alumina cement contained in the raw material is small. Since the melting point of the refractory increases by reducing the amount of CaO contained in the castable refractory, the corrosion resistance of the refractory after construction may be further improved. In this confirmation, in Invention Examples 11 to 13, the erosion index was smaller than in Invention Example 6, and the corrosion resistance was higher.
比較例６は、カーボンを含まないので施工性が向上し、混水量が低下したが、カーボンを含まないので、溶損指数は発明例６〜９よりも高くなり、耐食性が低下した。さらに、比較例６は、スラグ浸透厚みが著しく深くなった。比較例７は、比較例６より溶損指数が大きくなり、施工後の耐火物の耐食性が低下した。比較例７は、発明例６と同じ量の黒鉛を含むキャスタブル耐火物であるが、黒鉛がプラズマ処理されておらず黒鉛表面の疎水性が高いので当該キャスタブル耐火物の施工性が悪化した。このため、施工時の混水量が増加し、施工後の耐火物の見かけ気孔率が高くなり、耐火物の耐食性が低下した。 Comparative Example 6 did not contain carbon, so the workability was improved and the amount of mixed water was reduced. However, since it did not contain carbon, the erosion index was higher than that of Invention Examples 6 to 9, and the corrosion resistance was reduced. Further, in Comparative Example 6, the slag penetration thickness was significantly increased. In Comparative Example 7, the erosion index was larger than in Comparative Example 6, and the corrosion resistance of the refractory after construction was reduced. Comparative Example 7 is a castable refractory containing the same amount of graphite as Inventive Example 6, but the graphite was not plasma-treated and the graphite surface had high hydrophobicity, so that the workability of the castable refractory deteriorated. For this reason, the amount of water mixed during construction increased, the apparent porosity of the refractory after construction increased, and the corrosion resistance of the refractory decreased.
比較例８も比較例６より溶損指数が大きくなり、施工後の耐火物の耐食性が低下した。比較例８は、プラズマ処理された黒鉛を２５質量％で含有するキャスタブル耐火物であるが、キャスタブル耐火物中の黒鉛の微粉量が多くなりすぎ、当該キャスタブル耐火物の施工性が悪化した。このため、施工時の混水量が増加し、施工後の耐火物の見かけ気孔率が高くなり、耐火物の耐食性が低下した。 Comparative Example 8 also had a higher erosion index than Comparative Example 6, and the corrosion resistance of the refractory after construction was reduced. Comparative Example 8 is a castable refractory containing plasma-treated graphite at 25% by mass. However, the amount of graphite in the castable refractory was too large, and the workability of the castable refractory deteriorated. For this reason, the amount of water mixed during construction increased, the apparent porosity of the refractory after construction increased, and the corrosion resistance of the refractory decreased.
比較例９〜１２も比較例６より溶損指数が大きくなり、施工後の耐火物の耐食性が低下した。比較例９〜１２は、アルミナセメントに代えて、シリカゾル、アルミナゾル、塩基性乳酸アルミニウムまたはρ−アルミナを用いたキャスタブル耐火物であるが、黒鉛がプラズマ処理されておらず黒鉛の疎水性が高いので当該キャスタブル耐火物の施工性が悪化した。このため、プラズマ処理された黒鉛を用いた発明例１０〜１３よりも施工時の混水量が増加し、施工後の耐火物の見かけ気孔率が高くなり、耐火物の耐食性が低下した。 The erosion index of Comparative Examples 9 to 12 was larger than that of Comparative Example 6, and the corrosion resistance of the refractory after construction was reduced. Comparative Examples 9 to 12 are castable refractories using silica sol, alumina sol, basic aluminum lactate or ρ-alumina instead of alumina cement. However, graphite is not plasma-treated and graphite has high hydrophobicity. The workability of the castable refractory deteriorated. For this reason, the amount of water mixture at the time of construction increased compared with Invention Examples 10 to 13 using the plasma-treated graphite, the apparent porosity of the refractory after construction increased, and the corrosion resistance of the refractory decreased.
このように、Ａｌ２Ｏ３−ＭｇＯ−Ｃキャスタブル耐火物に、酸素を含有する気体をキャリアガスとしてプラズマ処理した黒鉛を１．０質量％以上２０．０質量％以下の範囲内で用いることで、黒鉛含有キャスタブル耐火物の施工性を向上できることが確認された。そして、当該黒鉛含有キャスタブル耐火物を少ない混水量で施工することで、施工後の耐火物の耐食性を向上でき、さらに、スラグ浸透厚みも浅くできることが確認された。また、硬化剤のアルミナセメントに代えて、シリカゾル、アルミナゾル、塩基性乳酸アルミニウムまたはρ−アルミナを用いることで、アルミナセメント由来のＣａＯ量を少なくでき、これにより、アルミナセメントを用いた場合と同等以上の耐食性が得られることが確認された。 As described above, the Al 2 O 3 —MgO—C castable refractory is manufactured by using the plasma-treated graphite in a range of 1.0% by mass to 20.0% by mass using a gas containing oxygen as a carrier gas. It was confirmed that the workability of graphite-containing castable refractories could be improved. Then, it was confirmed that by applying the graphite-containing castable refractory with a small amount of mixed water, the corrosion resistance of the refractory after the construction can be improved and the slag penetration thickness can be reduced. Further, in place of alumina cement as a curing agent, silica sol, alumina sol, basic aluminum lactate or ρ-alumina can be used to reduce the amount of CaO derived from alumina cement. It was confirmed that corrosion resistance was obtained.
１０ 鱗状黒鉛
１１ 鱗状黒鉛
１２ 水滴
１４ 接線
１６ 表面
DESCRIPTION OF SYMBOLS 10 Scale graphite 11 Scale graphite 12 Water drop 14 Tangent line 16 Surface
Claims (9)
アルミナ、マグネシア、スピネルおよび炭化珪素の１種以上と、
金属アルミニウム、金属シリコンおよび炭化ホウ素の１種以上と、
アルミナセメント、シリカゾル、アルミナゾル、塩基性乳酸アルミニウムおよびρ-アルミナの１種以上と、
分散剤と、を混合する黒鉛含有キャスタブル耐火物の製造方法であって、
前記プラズマ処理された黒鉛は、１．０質量％以上２０．０質量％以下の範囲内で混合される、黒鉛含有キャスタブル耐火物の製造方法。 Graphite whose surface is plasma treated,
One or more of alumina, magnesia, spinel and silicon carbide;
One or more of metal aluminum, metal silicon and boron carbide;
One or more of alumina cement, silica sol, alumina sol, basic aluminum lactate and ρ-alumina,
A method for producing a graphite-containing castable refractory by mixing a dispersant,
A method for producing a graphite-containing castable refractory, wherein the plasma-treated graphite is mixed within a range of 1.0% by mass to 20.0% by mass.
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