JP2007277021A - Refractory carbon material and application of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refractory carbon material which is hard to separate a carbon material even when kneaded with water and is hard to be porous even at high temperatures of 600°C or higher, and to provide a refractory raw material and a monolithic refractory raw material using the same. <P>SOLUTION: The refractory carbon material is composed of a boron-containing carbon black produced in the presence of a boron source in the process of pyrolysis and/or combustion reaction of a hydrocarbon. The boron-containing carbon black preferably has a boron content of 0.1-50 mass%. The refractory raw material is obtained by allowing the refractory carbon material to be contained in an inorganic filler comprising at least one selected among alumina, magnesia, and zirconia as a constituent. The content of the carbon material is preferably 1-20 mass%. The monolithic refractory raw material is obtained from the refractory raw material. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a refractory carbon material and its use.

A regular refractory and an amorphous refractory composed of an inorganic substance containing at least one selected from alumina, magnesia and zirconia as constituent components (hereinafter, both are also referred to as “refractories”) are furnaces and molten metals. Used for container linings, bowls, ladle. In order to improve the spalling resistance and corrosion resistance of the refractory, the refractory usually contains a carbon material such as graphite, pitch, coke, and carbon black. However, since the carbon material is hydrophobic, if the refractory material containing it is kneaded with water at the time of construction, the carbon material will be separated and sufficient carbon material effect will not be obtained, or the fluidity will be reduced and construction failure will occur. invited. Therefore, it has been proposed to treat the refractory raw material with a surfactant (Patent Document 1), but the refractory after construction tends to be porous at a high temperature of 600 ° C. or higher, and the corrosion resistance is lowered.
JP-A-10-287474

  An object of the present invention is to provide a carbon material for a refractory that is difficult to separate even when kneaded with water, and that is not easily porous even at a high temperature of 600 ° C. or higher, a raw material for a refractory using the same, an amorphous refractory It is to provide raw materials.

  The present invention is a refractory carbon material comprising a boron-containing carbon black produced in the presence of a boron source in at least one of the processes of hydrocarbon pyrolysis and combustion reaction. In the present invention, the boron content of the boron-containing carbon black is preferably 0.1 to 50% by mass. Moreover, this invention is the raw material for refractories which contains the carbon material for refractories of this invention in the inorganic powder which has at least 1 type chosen from the alumina, magnesia, and zirconia as a structural component. In this case, it is preferable that the content rate of a carbon material is 1-20 mass%. Furthermore, the present invention is an amorphous refractory material containing the refractory material of the present invention.

  According to the present invention, there is provided a refractory carbon material, a refractory raw material, and an amorphous refractory raw material which are difficult to separate even when kneaded with water and which are not easily porous even at a high temperature of 600 ° C. or higher. Provided.

  The boron-containing carbon black according to the present invention is produced in the presence of a boron source in at least one of the steps of hydrocarbon pyrolysis and combustion reaction, and its structure, method for measuring boron content, and production Details of the method and the like are described in JP-A No. 2000-281933. In the present invention, for example, those manufactured in the Examples of the same publication, or those heat-treated at a high temperature of 1500 ° C. or higher in a non-oxidizing atmosphere such as nitrogen or carbon dioxide are used. According to the latter, there exists an advantage which the oxidation resistance of a refractory improves further.

  The reason why the boron-containing carbon black has an excellent hydrophilic performance is that there is a surface functional group at the end of the solid solution or adhering boron existing on the surface of the carbon black. The reason why boron-containing carbon black has excellent antioxidant performance is that boric acid is generated when the boron-containing carbon black is oxidized, but volume expansion occurs in the generation process, and oxygen intrusion occurs. It is related to being suppressed.

  The boron content of the boron-containing carbon black is preferably 0.1% by mass or more. If it is less than 0.1% by mass, both hydrophilicity and oxidation resistance may be insufficient. The upper limit of the boron content is not particularly limited, but is preferably 50% by mass or less in order to mitigate a decrease in strength due to the generated boric acid and a decrease in corrosion resistance against slag and the like. A particularly preferable boron content is 0.1 to 20% by mass. The boron content can be adjusted by increasing / decreasing the amount of boron source added in the production in the presence of the boron source during at least one of the hydrocarbon pyrolysis and combustion reactions. It can also be adjusted by adding a boron compound to the obtained boron-containing carbon black or carbon black not containing boron.

  The refractory raw material of the present invention is obtained by adding the refractory carbon material of the present invention to an inorganic powder containing at least one selected from alumina, magnesia and zirconia as a constituent component. Examples of such inorganic powders include electrofused alumina, sintered alumina, calcined alumina, bauxite, banquetite, kyanite, mullite, rholite, quartzite, fused spinel, sintered spinel, fused. Examples include magnesia, sintered magnesia, zircon, zirconia, clay, bentonite and the like.

  The content of the inorganic powder containing at least one selected from alumina, magnesia and zirconia in the refractory raw material as a constituent component is preferably 50 to 99% by mass. If it is less than 50% by mass, the fire resistance is not sufficient, and if it exceeds 99% by mass, the spalling resistance and the corrosion resistance may be lowered. A particularly preferable content is 60 to 90% by mass. The refractory material can contain up to 40% by mass of a powder other than the inorganic powder. Examples of the powder that can be optionally included are silicon carbide, silicon nitride iron, silicon, ferrosilicon, aluminum, boron carbide, hydrous amorphous silica, anhydrous amorphous silica, graphite, pitch, coke, carbon fiber, For example, carbon black.

  Furthermore, the raw material for refractories of the present invention can be treated with a surfactant and may contain a binder. Examples of surfactants include polystyrene sulfonic acid, polycarboxylic acid, naphthalene sulfonic acid, alkylbenzene sulfonic acid, and polyacrylic acid. Examples of binders include alumina cement, PVA, phenolic resin, Arabic There is rubber.

  The amorphous refractory raw material of the present invention includes the refractory raw material of the present invention, and includes a casting material, a spraying material, and the like composed of the refractory raw material and water.

Examples 1-9, Comparative Examples 1-3
According to the example of JP 2000-281933 A, acetylene gas (hydrocarbon) and trimethyl borate gas are mixed at a predetermined ratio and installed at the top of a carbon black production furnace (furnace length 6 m, furnace diameter 1 m). The boron-containing carbon black having a boron content of 0.05, 0.3, or 10.3% by mass was produced by spraying from the nozzle formed and utilizing a thermal decomposition reaction of acetylene. The obtained boron-containing carbon black and inorganic powder were mixed at a ratio shown in Table 1 using a universal mixer. The obtained refractory raw material was used as an amorphous refractory raw material, and the following evaluations were performed in producing a casting material by kneading water until the fluidity capable of being applied was exhibited. The results are shown in Table 1.

(1) Separability of boron-containing carbon black from amorphous refractory raw material: 100 parts by mass of amorphous refractory raw material and 3 parts by mass of water were mixed, and the floating separation state of boron-containing carbon black was evaluated in four stages. (◎ No separation, ○ Trace separation, △ Separation, × Almost separation)
(2) Amount of construction water for the refractory raw material of irregular shape: The amount of water until it can be constructed (the fluidity that naturally forms a horizontal plane when the casting material is poured into a frame at room temperature of 25 ° C.) It was measured.
(3) Spalling resistance: A test piece (40 × 40 × 160 mm prismatic shape) obtained by pouring a casting material into a metal frame was heated in an electric furnace at 1500 ° C. × 30 minutes, and then cooled for 30 minutes. This cycle was repeated 30 times, and the occurrence of cracks was evaluated in three stages. (◎ No crack, ○ Some cracks, △ many cracks)
(4) Oxidation resistance: after the prismatic test piece was heated in an electric furnace at 1600 ° C. for 24 hours, it was cut at a longitudinal central portion 40 × 40 mm, and whitened on the front, rear, left and right sides of the cut surface. The thickness was measured and the average value was obtained.

  From Table 1, it can be seen that the refractory raw materials (unshaped refractory raw materials) produced according to the examples of the present invention have all the above-mentioned evaluation physical properties significantly superior to the comparative examples.

  The carbon material for a refractory of the present invention, the raw material for a refractory using the refractory, and the amorphous refractory can be used for a lining of a furnace or a molten metal container, a straw, a ladle or the like.

Claims (5)

A refractory carbon material comprising a boron-containing carbon black produced by the presence of a boron source in at least one of the process of thermal decomposition and combustion reaction of hydrocarbons. The carbon material for a refractory according to claim 1, wherein the boron-containing carbon black has a boron content of 0.1 to 50 mass%. A refractory raw material comprising the refractory carbon material according to claim 1 or 2 in an inorganic powder containing at least one selected from alumina, magnesia and zirconia as a constituent component. The refractory raw material according to claim 3, wherein the content of the refractory carbon material is 1 to 20% by mass. An amorphous refractory material comprising the refractory material according to claim 3 or 4.