JP4373081B2 - Refractory - Google Patents

Description

【００７６】
【表２】

【００７７】
比較例の各番号は本発明例の各番号と同材質系である。比較例１は通常のアルミナ−マグネシア質で、本発明例１はアルミナセメントを添加せずにグリコール酸乳酸アルミニウムと軽焼マグネシア微粉をアルミナ超微粉と併用したものである。以下、比較例２と本発明例２はアルミナ−スピネル質、３はアルミナ−スピネル−マグネシア質、４はアルミナ質、５はハイアルミナ質、６はマグネシア−スピネル質、７はマグネシア質、８はジルコン質、９はアルミナ−炭化珪素−カーボン質、１０はマグネシアカーボン質である。なお本発明例の８と９は乳酸アルミニウムを使用した。
本発明例は、いずれも対応する比較例よりも溶損が少なく、スラグ浸透も少なかった。またスポーリングも減少した。
【００７８】
［実施例２］
２７０トン溶鋼取鍋の底には本発明例２、側壁には本発明例１の流し込み材を使用して実機試験を行った。
底にはまずパーマれんがを施工し、続いて鋳造羽口、ポーラスプラグ、湯当たりブロックを設置してから水分６．５質量％を添加して混練した材料を流し込んで施工し、約２４時間常温で養生した。側壁はまずパーマれんがを施工してから中子を置き、６．５質量％の水を加えて混練した材料を流し込んで施工した。約２４時間養生した後、スラグラインにＭｇＯ−Ｃれんがを築造し、使用前に約１０００℃まで加熱し乾燥、予熱してから使用開始した。
【００７９】
通常の溶鋼取鍋ライニングは底が比較例２、側壁が比較例１の材料で、この場合の損耗速度は底が通常２．０mm/ch 側壁は０．９５mm/ch 程度である（ch＝チャージ：溶鋼鍋１杯を示す）。これに対して底の本発明例２の損耗速度は１．５mm/ch、側壁の本発明例１の損耗速度は０．６５mm/ch で、いずれも２５から３０％損耗速度抑制が図れた。また使用後耐火物中の亀裂も減少していた。
【００８０】
実機試験は溶鋼取鍋の内張りにおいて行なったが、本発明の耐火物はこれに限らず、タンデッシュ、真空脱ガス炉、転炉、電気炉等の設備の内張りにも広く使用することができる。
【００８１】
【発明の効果】
本発明の耐火物は、近年の鉄鋼精錬窯炉等おける過酷な使用条件においても優れた耐用性を発揮することができる。その結果、その稼働率向上、内張り耐火物の原単位や内張り耐火物の補修回数等を削減することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a refractory for casting construction or the like.
[0002]
[Prior art]
A refractory for casting construction (hereinafter referred to as “a casting material”) used as a refractory for a molten steel container such as a ladle, a tundish, a vacuum degassing furnace, or a molten steel processing apparatus is widely used. For example, Patent Document 1 and the like propose an alumina-magnesia casting material.
[0003]
However, the use conditions of molten steel containers and molten steel processing equipment in recent years have continued to become severe due to rising molten steel temperature, extension of molten metal time, gas blowing stirring, etc., for example, high durability such as alumina-magnesia However, the service life is never sufficient, and there is a strong demand for a casting material with excellent durability.
[0004]
As an improvement measure, Patent Document 1 proposes an alumina-magnesia casting material in which aluminum lactate is added to a binder. Here, aluminum lactate is used as the binder, and the alumina cement and SiO that are CaO sources.₂By removing the source silica, the effect of improving the resistance to melting loss and improving the heat spalling resistance by suppressing the sintering is obtained.
Patent Document 2 also proposes an alumina-magnesia casting material obtained by adding aluminum lactate to a binder as a material for wet spraying construction and excluding alumina cement as a CaO source.
[0005]
[Patent Document 1]
JP-A-11-130550
[Patent Document 2]
Japanese Patent Laid-Open No. 10-194853
[0006]
[Problems to be solved by the invention]
However, in the case of alumina-magnesia, the formation of low-melting-point substances is reduced except for alumina cement and silica, which slows the spinel formation reaction between alumina and magnesia. There is a problem that internal cracks or peeling damage occurs due to stress.
[0007]
Also, if alumina cement and silica are excluded, the formation of low melting point substances is suppressed, and the formation of a low melting point substance layer at the contact boundary with slag is reduced during refractory use. The effect of prevention is inferior. As a result, sufficient durability cannot be obtained due to peeling damage due to structural spalling and the cracks.
[0008]
When construction is carried out by spraying as in JP-A-10-194453, since the construction body structure is relatively porous, the spinel formation reaction is slow due to the small contact area between particles of alumina and magnesia, In addition, since the porous structure has an expansion absorption action, heat spalling resistance can be obtained by suppressing sintering by removing alumina cement and silica.
[0009]
On the other hand, in the pouring construction using a mold such as a core, the construction body structure is dense, and the material with only the removal of cement cannot avoid rapid expansion. In the lining for the molten steel processing apparatus, internal cracks or peeling damage due to expansion stress occurs.
[0010]
In addition, when aluminum lactate is used as a binder except for alumina cement or silica, defects in the construction body may occur because the shrinkage cracks that occur during curing cannot be suppressed. Since this crack facilitates the penetration of slag and molten steel into the internal structure during use of the refractory, it is inferior in the effect of preventing structural spalling suppression.
As a result, sufficient durability cannot be obtained due to peeling damage due to structural spalling and the cracks.
[0011]
The present invention provides a casting material that can prevent peeling damage and the occurrence of the cracks and obtain sufficient durability.
[0012]
[Means for Solving the Problems]
  In order to solve this problem, the gist of the present invention is as follows.
  (1) As a blending composition, 3 to 15% by mass of an alumina ultrafine powder having an average particle size of 1.5 μm or less, and one or more of aluminum lactate, aluminum glycolate, and aluminum glycolate in a total amount of 0 .01-2% by mass, iodine adsorption amount30-200Iodo mg /gIn addition, 0.01 to 3% by mass of light-burned magnesia fine powder having an average particle diameter of 1 μm or less is contained, and the chemical composition is 0.5% by mass or less of CaO, and the total amount of lactic acid and glycolic acid is 0.005 to 1% by mass MgO is 0.01 to 32% by mass, SiO₂0.05 to 50% by mass, the balance being Al₂O₃And other unavoidable ingredients.
  (2) As a blending composition, 3 to 15% by mass of ultrafine alumina powder having an average particle size of 1.5 μm or less, and one or more of aluminum lactate, aluminum glycolate, and aluminum glycolate in a total amount of 0.01 ~ 2 mass%, iodine adsorption amount30-200Iodo mg /gAnd 0.01-3 mass% of light-burning magnesia fine powder with an average particle diameter of 1 μm or less is contained, and the chemical composition is CaO.0.5Mass% or less, the total amount of lactic acid and glycolic acid is 0.005 to 1 mass%,ZrO ₂ But10-70% By mass, SiO₂But5-50mass%,MgO 0.01 ~ 5% By weight, balanceAl ₂ O ₃ And other unavoidable ingredients.
  (3) As a blending composition, 3 to 15% by mass of ultrafine alumina powder having an average particle size of 1.5 μm or less, and one or more of aluminum lactate, aluminum glycolate, and aluminum glycolate in a total amount of 0.01 ~ 2 mass%, iodine adsorption amount30-200Iodo mg /gIn addition, 0.01 to 3% by mass of light-burned magnesia fine powder having an average particle size of 1 μm or less is contained.0.5Mass% or less, the total amount of lactic acid and glycolic acid is 0.005 to 1 mass%,1 to 44% by mass of carbon,SiO₂But0.1-90mass%,1-80% by mass of SiC, 0.01-10% by mass of MgO,The restAl ₂ O ₃ And other unavoidable ingredients.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is characterized by not using alumina cement as a CaO source for the purpose of improving corrosion resistance and heat spalling resistance.
The CaO component is inevitably contained in refractory raw materials other than alumina cement, but its influence on corrosion resistance and spalling resistance is small compared to the intentionally added CaO component caused by alumina cement. This is probably because the CaO component in the refractory raw material is a stable compound, whereas the CaO component in the alumina cement is unstable and reacts with surrounding aggregates by receiving heat.
In the present invention, paying attention to the CaO component derived from alumina cement having a large adverse effect, and eliminating this, a highly durable refractory was obtained.
[0014]
The amount of CaO of the refractory of the present invention is a value that exceeds these inevitable amounts and does not intentionally add CaO. That is, the CaO component derived from refractory materials other than alumina cement is usually 0.5% by mass or less in the case of mainly alumina-based, alumina-silica-based, spinel-based, silica-based, zircon-based, zirconia-based materials, In the case of a magnesia-based material, it is 2% by mass or less, so these values are the upper limit of the CaO content. Moreover, although CaO in a refractory raw material cannot be ignored although it is comparatively few, it is necessary to regulate CaO content to below predetermined amount.
[0015]
The total amount of lactic acid and glycolic acid in the refractory of the present invention is 0.005 to 1% by mass. This is an amount corresponding to the added amount of 0.01 to 2% by mass of aluminum lactate, aluminum glycolate, aluminum glycolate and the like described later. Aluminum lactate, aluminum glycolate, and aluminum glycolate are composed of lactic acid, glycolic acid, and aluminum ions (or aluminum oxide in terms of oxides), so the amount of lactic acid or glycolic acid is aluminum lactate, aluminum glycolate, glycol glycol Less than the amount of aluminum oxide added.
If the amount of lactic acid or glycolic acid is less than 0.005% by mass, there is no effect of generation of fine cracks due to expansion and contraction, and if it exceeds 1% by mass, cracks due to curing shrinkage occur and the corrosion resistance deteriorates.
[0016]
From the viewpoint of the chemical composition of the refractory, Al₂O_Three, SiO₂, ZrO₂In the case of a refractory with a large amount, CaO is 0.5% by mass or less, and in the case of a refractory with a large amount of MgO, CaO is 2% by mass or less, and the total amount of lactic acid and glycolic acid is 0.005 to 1% by mass. .
[0017]
The chemical composition and composition of various refractories are described below.
The invention according to (1) is an Al₂O_ThreeIt is a refractory material mainly composed of alumina-based or alumina-silica-based raw materials, that is, alumina-magnesia, alumina-spinel, alumina-spinel magnesia, high alumina refractory, and its chemical composition is , CaO is 0.5 mass% or less, the total amount of lactic acid and glycolic acid is 0.005 to 1 mass%, MgO is 0.01 to 32 mass%, SiO₂0.05 to 50% by mass, the balance being Al₂O_ThreeAnd other inevitable ingredients.
The reason for defining the total amount of CaO, lactic acid and glycolic acid in this way is as described above.
[0018]
MgO is derived from light-burned magnesia, magnesia-based raw materials, dolomite-based raw materials, spinel-based raw materials, etc. If MgO content is less than 0.01% by mass, the shrinkage during curing is not sufficient, and if it exceeds 32% by mass, magnesia is Hydration causes problems such as cracks in the construction body and increased slag infiltration.
[0019]
SiO₂Is derived from silica-based raw materials such as volatile silica and alumina-silica-based raw materials, and if it is less than 0.05% by mass, the thermal shock resistance of the construction body deteriorates, or magnesia hydrates, and 50 masses. If it exceeds 50%, the corrosion resistance deteriorates.
[0020]
The balance is Al₂O_ThreeAnd other inevitable ingredients.
Al₂O_ThreeIs derived from raw materials such as alumina, alumina-silica, and spinel. Inevitable ingredients are iron oxide, MnO, TiO₂, Na₂O, P₂O_Five, V₂O_Five, C and other elements having stable nuclides, or compounds such as oxides, both of which adversely affect the corrosion resistance and the like, and are desirably 5% by mass or less.
[0021]
If the amount of lactic acid and glycolic acid in the refractory is managed, the performance of the refractory can be managed and grasped more accurately than the addition ratio of aluminum lactate, aluminum glycolate, aluminum glycolate and the like to be described later. This is because commercially available aluminum lactate, aluminum lactate glycolate, and aluminum glycolate contain diluents and extenders, and the amount of components such as aluminum lactate is not constant.
[0022]
In the present invention, the following method was used as a method for measuring the amounts of lactic acid and glycolic acid in the refractory. That is, in accordance with the dissolution test method of soil etc. of Environment Agency Notification No. 46, a sample of 2 mm or less and a pure water adjusted to pH 5.8 to 6.3 is 10% by mass / volume ratio (50 g of sample and 500 ml of pure water). Mix at a rate and shake continuously for 6 hours at room temperature and normal pressure using a shaker (shaking width 4-5 cm, 200 times per minute). The solution was allowed to stand for 30 minutes, and then the supernatant obtained by centrifuging at about 3000 revolutions per minute was filtered through a membrane filter having a pore size of 0.45 μm to obtain a measurement solution.
[0023]
This was measured by capillary zone electrophoresis or high performance liquid chromatography. In capillary zone electrophoresis, fused silica capillaries were used, and sample injection was performed by the drop method. Detection was based on ultraviolet absorption by the on-column method. In the high performance liquid chromatograph method, an ordinary column having an inner diameter of 3 to 4 mm was used, and the ultraviolet absorbance was measured at a flow rate of about 0.5 to 2 ml / min. The detection sensitivity is superior to capillary electrophoresis. The difference between the two results was within 20%.
[0024]
The present invention according to the above (2) is a refractory material such as magnesia or magnesia spinel with many MgO components, and the composition is such that CaO is 2 mass% or less and the total amount of lactic acid and glycolic acid is 0.005 to 0.005. 1% by mass, Al₂O_Three0.1 to 45 mass%, SiO₂Is 0.05 to 5% by mass, and the balance is MgO and other inevitable components.
[0025]
Al₂O_ThreeIs derived from ultrafine alumina powder, alumina-based raw material, spinel-based raw material, etc., and 0.1 mass% or more is necessary for suppressing slag infiltration and imparting strength, but if it exceeds 45 mass%, the corrosion resistance decreases.
[0026]
SiO₂Is derived from silica-based raw materials, magnesia-based raw materials, and the like, and 0.05% by mass is necessary to prevent hydration of magnesia, but if it exceeds 5% by mass, the corrosion resistance decreases.
[0027]
The balance is MgO and other inevitable components. MgO is derived from light-burned magnesia, magnesia-based materials, dolomite-based materials, spinel-based materials, and the like. Inevitable ingredients are iron oxide, MnO, TiO₂, Na₂O, P₂O_Five, V₂O_Five, B₂O_Three, C or other elements having stable nuclides, or compounds such as oxides, and the like, and desirably 5 mass% or less so as not to impair the corrosion resistance.
[0028]
The present invention according to the above (3) is a refractory rich in zircon or zirconia, and its chemical composition is 0.5 mass% or less of CaO, the total amount of lactic acid and glycolic acid is 0.005 to 1 mass%, ZrO₂10 to 70 mass%, SiO₂5-50 mass%, MgO 0.01-5 mass%, the balance is Al₂O_ThreeAnd other inevitable ingredients.
[0029]
ZrO₂Is derived from zircon or zirconia, and if it is less than 10% by mass, sufficient corrosion resistance cannot be obtained. If it exceeds 70% by mass, the spalling resistance may be deteriorated.
[0030]
SiO₂Is derived from silica-based and alumina-silica-based raw materials. SiO₂If it is less than 5% by mass, the spalling resistance deteriorates, and if it exceeds 50% by mass, the corrosion resistance deteriorates.
[0031]
MgO is derived from light-burned magnesia, magnesia-based raw materials, dolomite-based raw materials, spinel-based raw materials, and the like. If it is 5% or more, the corrosion resistance is adversely affected.
[0032]
The balance is Al₂O_ThreeAnd other inevitable ingredients. Al₂O_ThreeIs derived from raw materials such as alumina, alumina-silica, and spinel. Inevitable ingredients are iron oxide and TiO₂, Na₂O, V₂O_Five, P₂O_FiveDesirably, it is 5% by mass or less so as not to deteriorate the corrosion resistance with an element having a stable nuclide or a compound such as an oxide.
[0033]
This invention which concerns on said (4) is related with a refractory with many alumina, silica, carbon, and silicon carbide, CaO is 0.5 mass% or less, and the total amount of lactic acid and glycolic acid is 0.005-1 mass. %, 1 to 44% by mass of carbon, SiO₂Is 0.1 to 90% by mass, SiC is 1 to 80% by mass, MgO is 0.01 to 10% by mass, and the balance is Al.₂O_ThreeAnd other inevitable ingredients.
[0034]
Carbon is derived from carbon itself and a silicon carbide-based raw material, and if it is less than 1% by mass, the slag infiltration resistance and corrosion resistance decrease, and if it exceeds 44% by mass, oxidation wear increases.
[0035]
SiO₂Is derived from alumina-silica, both silica-based raw materials and silicon carbide-based raw materials. If the amount is less than 0.1% by mass, the sinterability is insufficient and the hot strength is hardly exhibited, and if it exceeds 90% by mass, the corrosion resistance is deteriorated. .
[0036]
SiC is derived from a SiC raw material, and if it is less than 1% by mass, the corrosion resistance is insufficient, and if it exceeds 80% by mass, there is a concern about oxidation wear.
[0037]
MgO is derived from light-burned magnesia, magnesia-based material, dolomite-based material, spinel-based material, and the like. If it is less than 0.01% by mass, shrinkage during curing cannot be sufficiently suppressed, and if it exceeds 10% by mass, slag infiltration increases.
[0038]
The balance is Al₂O_ThreeAnd other inevitable ingredients, Al₂O_ThreeIs derived from raw materials of alumina ultrafine powder, alumina, alumina-silica, silica, and spinel. Other components are iron oxide and TiO₂, Na₂O, V₂O_Five, P₂O_FiveIn order not to impair the corrosion resistance, it is preferably 5% by mass or less with an element having a stable nuclide or a compound such as an oxide.
[0039]
This invention which concerns on said (5) is a refractory material with much magnesia and carbon, The chemical composition is 2 mass% or less of CaO, the total amount of lactic acid and glycolic acid is 0.005-1 mass%, and carbon is 0 .5-30% by mass, SiO₂0.05 to 20 mass%, Al₂O_Three0.1 to 15% by mass, the balance being MgO and other inevitable components.
[0040]
When carbon derived from organic substances such as carbon-based raw materials and resins is less than 0.5% by mass, slag infiltration is large, and when it exceeds 30% by mass, oxidation wear increases.
[0041]
SiO₂If it is less than 0.05% by mass, magnesia hydrates, and if it exceeds 20% by mass, the corrosion resistance decreases.
[0042]
Al₂O_ThreeHowever, if it is less than 0.1% by mass, sufficient strength is not exhibited, and if it is 15% by mass or more, the corrosion resistance decreases.
[0043]
The balance is MgO and other inevitable components, and MgO is derived from light-burned magnesia, magnesia, dolomite, and spinel materials. Other inevitable ingredients are the above-mentioned raw materials and borides, glass powders, metal powders, binders, curing regulators, iron oxides, MnO, P₂O_Five, B₂O_ThreeIn order to prevent the corrosion resistance from being deteriorated by an element having a stable nuclide or a compound such as an oxide, the content is desirably 10% by mass or less.
[0044]
  Said(1)-(5)In the invention according to the present invention, alumina fine powder, one or more of aluminum lactate, aluminum glycolate, and aluminum glycolate, and light-burned magnesia fine powder are added without blending alumina cement. That is, the strength after curing is ensured by ultrafine alumina powder, aluminum lactate, aluminum glycolate, and aluminum glycolate, and cracking during curing is suppressed by light-burned magnesia fine powder.
[0045]
  The alumina ultrafine powder imparts strength to the construction body due to its cohesive force. In addition, since the structure is densified, corrosion resistance and slag infiltration resistance are improved.(1)-(5)In the invention according to the above, ultrafine alumina powder having an average particle size of 1.5 μm or less is combined. This enhances the filling property of the matrix part of the construction body structure, eliminates the extra space between the particles, and prevents shrinkage cracks associated with the gelation of aluminum lactate, glycolate aluminum lactate, and aluminum glycolate described later. The effect of is made more certain.
[0046]
The amount of the ultrafine alumina powder is 3 to 15% by mass with respect to 100% by mass of the refractory aggregate composition, and the average particle size is 1.5 μm or less. If the ratio of the ultrafine alumina powder is less than 3% by mass, the effect of preventing shrinkage cracking of the construction body is inferior, and if it exceeds 15% by mass, the spinel reaction may be excessive or the spalling resistance may be lowered. The filling property and the strength of the construction body that the average particle diameter exceeds 1.5 μm cannot be obtained.
[0047]
The use of calcined alumina is preferable because the ultrafine alumina powder is easily available from commercial products. The calcined alumina is known in various particle sizes. In the present invention, as long as 3 to 15% by mass of alumina ultrafine powder having an average particle diameter of 1.5 μm or less is used, alumina ultrafine powder having other particle diameters may be combined. Moreover, you may combine multiple alumina ultrafine powder from which a particle size differs in the range of an average particle size of 1.5 micrometers or less.
[0048]
Aluminum lactate, aluminum glycolate, and aluminum glycolate play a role as a binder that hardens the cast material during curing by gelation by reaction with construction water. To form fine cracks. The microcracks remain in the structure when the construction body is dried and heated, thereby effectively working to impart air permeability, absorb expansion, and reduce thermal stress.
[0049]
If the addition amount of aluminum lactate, aluminum glycolate, or aluminum glycolate is less than 0.01% by mass, there is no effect of expansion absorption, and if it exceeds 2% by mass, the corrosion resistance decreases. Moreover, you may perform the addition in the state previously thawed with water.
Furthermore, by adding light-burned magnesia, the intended effects of volume stability and corrosion resistance can be obtained. The reason is considered as follows.
[0050]
The fine cracks due to the gelation reaction of aluminum lactate, aluminum glycolate, and aluminum glycolate are effective in absorbing the expansion of the construction as described above, but at the same time cracks due to curing shrinkage occur. This crack due to curing shrinkage has a much larger crack width than the fine crack caused by the gelation reaction, and causes a decrease in corrosion resistance.
[0051]
On the other hand, by combining light-burned magnesia, gelled aluminum lactate, glycolate aluminum lactate, and aluminum glycolate are adsorbed to Mg eluted from the light burnt magnesia during kneading, and aluminum lactate, aluminum glycolate, lactate, glycolic acid By suppressing the rapid gelation reaction observed when aluminum is used alone, shrinkage cracks during curing are prevented.
[0052]
Moreover, it is in the curing form in which magnesia and alumina are already bonded at the time of curing by reaction of light-burned magnesia with aluminum lactate, aluminum glycolate, and aluminum glycolate, and these are spineled at a relatively low temperature range. The spinel produced here has a very fine particle size. This contributes greatly to the improvement of corrosion resistance and volume stability in combination with the prevention of shrinkage cracks during curing.
[0053]
These effects according to the present invention are such that, among light-burned magnesia, the iodine adsorption amount is 20 iodine mg / g or more, more preferably 30 to 200 iodine mg / g, and the average particle size is 1 μm or less, more preferably 0.5 μm or less. It is demonstrated for the first time by using light-burned magnesia fine powder. If the lightly adsorbed magnesia fine powder has an iodine adsorption amount of less than 20 iodomg / g, the reaction with aluminum lactate, aluminum glycolate, or aluminum glycolate is inferior, or there is no effect in preventing shrinkage cracks during curing. On the other hand, if the iodine adsorption amount of the light-burned magnesia fine powder exceeds 200 iodine mg / g, the hydration reaction tends to occur and the digestion resistance of the refractory structure tends to decrease, such being undesirable.
[0054]
If the average particle size exceeds 1 μm, the reaction with aluminum lactate, aluminum glycolate, or aluminum glycolate is slow even when the iodine adsorption amount is 20 iodomg / g or more. There is no prevention effect. Even if either the iodine adsorption amount or the average particle diameter is out of this range, the effect aimed by the present invention cannot be obtained.
[0055]
The measurement of the iodine adsorption amount here can be performed according to JIS-K6338 which is a method for measuring the surface properties of magnesia fine powder. The average particle size can be measured by a laser diffraction method. Moreover, the particle size measurement of the alumina ultrafine powder mentioned later can also be measured by the laser diffraction method.
[0056]
If the amount of lightly burned magnesia fine powder is less than 0.01% by mass in the proportion of 100% by mass of the refractory aggregate composition, there is no effect of preventing curing shrinkage. When the amount exceeds 3% by mass, the casting material has a high viscosity during kneading, and it is difficult to obtain a dense construction body due to a decrease in fluidity during construction.
[0057]
The light-burned magnesia fine powder is obtained by baking magnesium hydroxide at a relatively low temperature range, and the amount of iodine adsorption varies depending on operations such as particle size adjustment and baking temperature in the production process. Various qualities are commercially available in terms of iodine adsorption amount and particle size, and the light-burned magnesia fine powder used in the present invention can also be obtained from this commercially available product. In addition, if the amount of light-burned magnesia fine powder with the iodine adsorption amount and particle size limited in the present invention is used in an amount within the range limited in the present invention, the amount of light-burned magnesia fine powder with other iodine adsorption amount and particle size is used in combination. May be.
[0058]
Aluminum lactate includes basic aluminum lactate, aluminum citrate aluminum lactate and the like as described in JP-A-9-194264, including aluminum lactate in a narrow sense. For example, basic aluminum lactate is produced by reacting water-soluble aluminum with carbonate or carbonate and lactic acid. Al for aluminum lactate₂O_Three/ Lactic acid having a molar ratio of 0.3 to 2 is preferable, but is not limited thereto.
[0059]
Aluminum glycolate is included in a broad sense of aluminum lactate. For example, it can be obtained by preparing a mixed solution of aluminum lactate and glycolic acid, which is an organic acid, and drying it. Al₂O_ThreeAlthough / (lactic acid + glycolic acid) is preferably 0.3 to 2 in terms of molar ratio, it is not limited thereto.
Aluminum glycolate is Al₂O_Three/ Glycolic acid preferably has a molar ratio of 0.3 to 2, but is not limited thereto.
[0060]
The raw material used for the refractory of the present invention will be described below.
The alumina material is a refractory material having both corrosion resistance and volume stability. It does not matter whether it is an electromelted product or a sintered product. For use in the fine powder portion, calcined alumina that is easily available as fine powder may be used. Al₂O_ThreeThe purity is preferably 95% by mass or more.
The magnesia-based raw material used in the present invention may be either a sintered product or an electromelted product. The MgO purity is 90% by mass or more, more preferably 95% by mass.
A part or all of the magnesia-based raw material used in the present invention may be a magnesium carbonate raw material having an MgO content of 35% by mass or more as a chemical analysis value. As the magnesium carbonate, natural magnesite, synthetic magnesium carbonate, magnesium carbonate hydroxide (basic magnesium carbonate) or the like can be used, and the MgO content is preferably 35% by mass or more and the particle size is preferably 1 mm or less.
[0061]
Magnesium carbonate raw material is decomposed from around 600 ° C (MgCO_Three→ MgO + CO₂) To generate fine voids in the construction body structure. In addition to absorbing and mitigating the expansion of the refractory, the fine voids prevent oversintering of the surface layer during use of the construction body and exhibit an excellent effect on structural spalling. From the viewpoint of corrosion resistance, the proportion of the magnesium carbonate raw material is more preferably 70% by mass or less of the entire magnesia raw material or 10% by mass or less as a proportion of the entire refractory aggregate.
The particle size of the magnesia material is adjusted to coarse particles, medium particles, and fine particles in consideration of the fluidity at the time of casting material construction or the filling property of the construction body as in the case of the alumina material described later.
[0062]
Volatile silica, meteorite, etc. can be used as the silica-based raw material. Volatile silica is added to alumina-magnesia amorphous refractories and basic amorphous refractories, and is effective for relaxation of expansion stress during spinel formation and suppression of magnesia hydration. Volatile silica is obtained, for example, as a by-product in the production of silicon or silicon alloys, and is marketed under a trade name such as silica flour or microsilica. Ultrafine particles with an average particle size of 1 μm. The blending ratio is preferably 3% by mass or less based on the entire refractory aggregate. When it exceeds 3 mass%, a low melting point substance will be produced | generated more and corrosion resistance will fall. The most preferred range is 0.05 to 1.5 mass%.
[0063]
As the spinel-based material, electrofused or sintered spinel, spinel ore, etc. can be used. Al₂O_ThreeImpurities other than MgO are preferably less than 80% by mass. Even those outside the stoichiometric composition can be used.
[0064]
Examples of the alumina-silica-based raw material include wax, clay, chamotte, sillimanite, andalusite, kayanite, natural or synthetic sintered or electrofused mullite, porphyry shale, bauxite, and the like. Any of them may be a normal product.
[0065]
The zircon material can be natural zircon sand or zircon flower, and the zirconia material can be natural budeleite or synthetic zirconia. In either case, normal products can be used.
[0066]
Synthetic products and natural products can be used as dolomite-based raw materials. What performed the process for improving hydration resistance is suitable for the refractory material for casting construction.
As the carbon-based raw material, those commonly used can be used. For example, scaly graphite, carbon black, anthracite, earthy graphite, electrode scraps, powder pitch, etc. can be given as examples of the carbon-based raw material.
[0067]
The carbide-based material is a silicon carbide-based material or the like, and a silicon carbide material that is normally used for refractories can be used.
B as a boride_FourC, CaB₆, ZrB₂Etc. can be used.
In addition, raw materials used for other refractories, such as glass powder, can be added.
[0068]
The metal powder is added to suppress the oxidation of the carbon-based raw material and improve the strength of the refractory, and one or more kinds of metal aluminum, metal silicon, metal magnesium, metal calcium, or a mixture or compound thereof can be used. The particle size is desirably 1 mm or less.
For example, hydraulic alumina fine powder may be added as a binder. Unlike alumina cement, hydraulic alumina fine powder does not cause a decrease in corrosion resistance, and also has an effect of preventing a protrusion due to expansion of the construction body.
[0069]
In addition, peptizers, refractory coarse particles, hardening modifiers, short metal fibers (for example, stainless steel fibers), organic fibers, ceramic fibers, carbon fibers, chromium ores, foaming agents, etc., known as additives for casting materials It may be added.
You may add a boric acid, lithium carbonate, etc. as a hardening regulator. The addition amount is usually 0.5% by mass or less.
In particular, the addition of peptizer is necessary to impart fluidity during construction. Specific examples include sodium tripolyphosphate, sodium hexametaphosphate, ultrapolyphosphate soda, acid hexametaphosphate soda, sodium borate, sodium citrate, carboxyl group-containing polyether dispersant, sodium tartrate, sodium polyacrylate, sulfone. There is acid soda. The addition ratio is preferably 0.01 to 0.5% by mass with respect to 100% by mass of the refractory aggregate.
[0070]
The coarse refractory particles have an effect of preventing peeling damage by cutting off the development of cracks generated in the refractory structure. Specific examples are alumina, spinel, mullite, magnesia and the like. Further, brick scraps mainly composed of alumina or spinel, and products after using refractories may be used. The particle size of the refractory coarse particles is preferably 10 to 50 mm, although there is a balance with the maximum particle size of the refractory aggregate. In addition, the ratio is preferably 35% by mass or less, more preferably 5 to 30% by mass, based on 100% by mass of the refractory aggregate. If it exceeds 35% by mass, the strength of the construction body is inferior due to the poor balance of the particle size constitution, and the corrosion resistance is reduced.
[0071]
Each component in the refractory can be quantitatively analyzed by a fluorescent X-ray method using a glass bead sample. In general, carbon is oxidized by heating and analyzed as a gas.
[0072]
The refractory material of the present invention can be used as a casting material, and can also be used as a dry or wet spray material, plastic refractory material, patching material, stamp material, ramming material, sling material, coating material, mortar and the like. Adjust the amount and type of binders and additives as needed. The construction method may be as usual according to each type of refractory.
In the case of a casting material, about 4 to 8% by mass of construction water is added to the entire blended composition as described above, and casting is performed using a mold such as a core. Moreover, it is good to improve a filling rate by giving a vibration at the time of pouring.
[0073]
【Example】
[Example 1]
Examples of the present invention carried out with the casting material and comparative examples thereof are shown below. In each example, 6.5% by mass of working moisture was added to the entire composition shown in Table 1 and Table 2 and kneaded, poured into a mold, applied, cured, and dried at 110 ° C. for 24 hours for testing. I got a piece. The amount of CaO in the table is a numerical value converted as the amount of CaO by multiplying the mass of each compound by the CaO concentration.
In addition, calcined alumina manufactured by Showa Denko Co., Ltd. was used as the ultrafine alumina powder in each example. As the volatile silica, silica flour manufactured by Elchem Co., Ltd. was used. Aluminum lactate and aluminum glycolate are manufactured by Taki Chemical Co., Ltd.
[0074]
The test method is as follows.
Corrosion resistance: Steel slab: converter slag (FeO content; 20% by mass) = 50: 50 was used as an erodant by mass ratio, and a erosion test was conducted at 1700 ° C. for 5 hours to measure a erosion dimension.
Resistance to slag penetration; after performing a rotary erosion test under the above conditions, the slag penetration dimension was measured.
Spalling resistance: Steel slab by mass ratio: Converter slag (FeO content; 20 mass%) = 50:50 as an erodant, heated at 1700 ° C. for 30 minutes using a rotary erosion test apparatus, and then air-cooled for 30 minutes Then, this was repeated 6 times, and the state of crack generation was observed. ◎: no crack, ○: micro crack (with a width of hair crack that can be visually confirmed), △: small crack (crack with a width of approximately 0.3 mm or less), ×: large crack (with a width of approximately 0.00 mm). This shows that a crack of more than 3 mm has occurred.
[0075]
[Table 1]

[0076]
[Table 2]

[0077]
Each number of the comparative example is the same material system as each number of the present invention example. Comparative Example 1 is a normal alumina-magnesia, and Example 1 of the present invention is a combination of aluminum glycolate and light calcined magnesia fine powder combined with ultrafine alumina powder without adding alumina cement. Hereinafter, Comparative Example 2 and Invention Example 2 are alumina-spinel, 3 is alumina-spinel-magnesia, 4 is alumina, 5 is high alumina, 6 is magnesia-spinel, 7 is magnesia, 8 is Zircon, 9 is alumina-silicon carbide-carbon, and 10 is magnesia carbon. In Examples 8 and 9, aluminum lactate was used.
The inventive examples had less melting loss and less slag penetration than the corresponding comparative examples. Spalling also decreased.
[0078]
[Example 2]
An actual machine test was performed using the casting material of the present invention example 2 on the bottom of the 270-ton ladle ladle and the casting material of the present invention example 1 on the side wall.
Perm brick is first applied to the bottom, then cast tuyere, porous plug, block per hot water, and then poured into the kneaded material with addition of 6.5% by weight of water and applied for about 24 hours at room temperature. Cured with. First, permanent bricks were applied to the side walls, then the core was placed, and the material kneaded by adding 6.5% by mass of water was applied. After curing for about 24 hours, a MgO-C brick was built on the slag line, heated to about 1000 ° C. before use, dried and preheated before use.
[0079]
The normal ladle lining is the material of Comparative Example 2 at the bottom and Comparative Example 1 at the side wall. In this case, the wear rate is usually about 2.0 mm / ch at the bottom and about 0.95 mm / ch at the side wall (ch = charge). : Shows 1 cup of molten steel). On the other hand, the wear rate of Invention Example 2 at the bottom was 1.5 mm / ch, and the wear rate of Invention Example 1 at the side wall was 0.65 mm / ch. In addition, cracks in the refractory after use were reduced.
[0080]
Although the actual machine test was performed on the lining of the molten steel ladle, the refractory according to the present invention is not limited to this, and can be widely used for lining of equipment such as tundish, vacuum degassing furnace, converter, electric furnace and the like.
[0081]
【The invention's effect】
The refractory of the present invention can exhibit excellent durability even under severe use conditions in recent steel refining furnaces and the like. As a result, the operating rate can be improved, the basic unit of the lining refractory, the number of repairs of the lining refractory, and the like can be reduced.

Claims (3)

As a blending composition, 3 to 15% by mass of alumina ultrafine powder having an average particle size of 1.5 μm or less, and one or more of aluminum lactate, aluminum glycolate, and aluminum glycolate in a total amount of 0.01 to 2 mass%, iodine adsorption amount 30-200 iodine mg / g, containing 0.01-3 mass% light-burned magnesia fine powder having an average particle size of 1 μm or less, and, as a chemical composition, CaO is 0.5 mass% or less The total amount of lactic acid and glycolic acid is 0.005 to 1% by mass, MgO is 0.01 to 32% by mass, SiO ₂ is 0.05 to 50% by mass, the balance is Al ₂ O ₃ and other inevitable components. A refractory characterized by consisting of. As a blending composition, 3 to 15% by mass of alumina ultrafine powder having an average particle size of 1.5 μm or less, and one or more of aluminum lactate, aluminum glycolate, and aluminum glycolate in a total amount of 0.01 to 2 mass%, iodine adsorption amount 30-200 iodine mg / g, containing 0.01-3 mass% light-burned magnesia fine powder having an average particle size of 1 μm or less, and, as a chemical composition, CaO is 0.5 mass% or less The total amount of lactic acid and glycolic acid is 0.005 to 1% by mass, ZrO ₂ is 10 to 70% by mass, SiO ₂ is 5 to 50% by mass, MgO is 0.01 to 5% by mass, and the balance is Al ₂ O. ₃ and other unavoidable ingredients. As a blending composition, 3 to 15% by mass of alumina ultrafine powder having an average particle size of 1.5 μm or less, and one or more of aluminum lactate, aluminum glycolate, and aluminum glycolate in a total amount of 0.01 to 2 mass%, iodine adsorption amount 30-200 iodine mg / g, containing 0.01-3 mass% light-burned magnesia fine powder having an average particle size of 1 μm or less, and, as a chemical composition, CaO is 0.5 mass% or less The total amount of lactic acid and glycolic acid is 0.005 to 1% by mass, carbon is 1 to 44% by mass, SiO ₂ is 0.1 to 90% by mass, SiC is 1 to 80% by mass, and MgO is 0.01 to A refractory material characterized by comprising 10% by mass and the balance comprising Al ₂ O ₃ and other inevitable components.