JP2003207275A - Crucible, fusing vanadium and its compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fusing crucible capable of fusing vanadium and its compound while retaining purity thereof. <P>SOLUTION: In this crucible for fusing vanadium and its compound, a silicon carbide layer is provided on at least an inner face of the crucible made of a material other than silicon carbide. The crucible made of a material of various oxides such as alumina, magnesium oxide, calcium oxide, beryllium oxide, zirconium oxide, and quartz other than silicon carbide, and graphite, and coated with silicon carbide on its inner face, is used as the crucible for fusing vanadium and its compound. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a crucible for use in melting vanadium and vanadium compounds.

[0002]

2. Description of the Related Art As vanadium ores used as a raw material for vanadium pentoxide, vanadium mica, motterum ore, carnotite, patronite, vanadium lead ore, etc. are known. After mixing, roasting at about 850 ° C., leaching the obtained baked product with warm water and filtering to obtain a sodium metavanadate solution, and then adding sulfuric acid to this solution to adjust the pH to 1 to 3,
Polyvanadate is precipitated and subsequently dried to give vanadium pentoxide.

Metal vanadium obtained by the calcium reduction method of vanadium pentoxide is mainly used as an additional element for alloys. For example, vanadium as an alloying element is widely used in the form of ferrovanadium because it promotes the refinement of crystal grains of steel materials and stabilizes carbides to improve their performance. Also, titanium, zirconium,
It is also used as an alloying element to copper.

On the other hand, vanadium pentoxide has a melting point of about 670.
Relatively low at ℃, it is a type of oxide semiconductor and is used as a ferrovanadium and vanadium steel raw material, as a catalyst, a desiccant for paints and inks, and as a brightening agent for glass and ceramics. Conventionally, when melting vanadium pentoxide, which is also used as an electrode material for a battery, a crucible is generally used as a ferrous material such as MgO, A1 ₂ 0 ₃ , Ti0 ₂ , CaO, and B.
When a crucible made of a material such as eO or graphite is used, vanadium pentoxide reacts with these materials, and there is a problem that the crucible material is mixed into vanadium pentoxide as an impurity. Naturally, the erosion of the crucible gradually progresses, which causes a problem that the cost is increased due to the consumption of the crucible.

As described above, in the conventional technique, since the reactivity of vanadium and vanadium pentoxide is high, it is possible to simultaneously achieve both the objectives of melting while maintaining the purity of the raw material and at a low cost. Had a problem that it was difficult.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and it is intended for melting vanadium and its compounds while maintaining the purity and at a low cost. The purpose is to provide crucibles.

[0007]

The present invention for solving the above-mentioned problems is characterized in that at least the inner surface of a crucible made of a material other than silicon carbide is made of silicon carbide. Materials other than silicon carbide in the present invention include various oxides such as alumina, magnesium oxide, calcium oxide, beryllium oxide, zirconium oxide, and quartz, and graphite.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The melting crucible for vanadium and its compounds according to the present invention comprises a relatively low cost material such as oxide or graphite as a crucible body serving as a saucer for holding molten metal such as vanadium pentoxide. Since the inner surface that directly contacts the molten metal such as vanadium pentoxide is made of silicon carbide that does not react with the molten metal or hardly reacts with it, it is possible to maintain the purity of the melting raw material at a low cost. Both of the melting can be done at the same time.

[0009]

EXAMPLES Next, the present invention will be further described with reference to examples. (Example) 3 kg of vanadium pentoxide was placed in a melting crucible in which the inner surface of an alumina crucible body having a diameter of 200 mm and a depth of 150 mm was coated with silicon carbide, heated to 850 ° C. to be melted, and allowed to stand at that temperature for 24 hours, The molten metal was made uniform.

After that, the molten metal was poured into a mold made of silicon carbide, and casting was performed to obtain a width of 100 mm and a length of 300 mm.
An ingot having a thickness of 30 mm was obtained. The amount of alumina and silicon in this ingot was analyzed. The obtained values were <0.01% for Al, which was below the detection limit, and Si was <0.01. Further, when the inner surface of the crucible was observed, no damaged state could be confirmed.

(Conventional Example) Vanadium pentoxide was dissolved in the same manner as in Example 1 except that the inner surface of the alumina crucible was not coated with silicon carbide to obtain an ingot. The amount of alumina and silicon in the ingot was 0.23, <
It was 0.01, and the inner surface of the crucible was also eroded.

[0012]

INDUSTRIAL APPLICABILITY The melting crucible of the present invention is a cheap crucible made of various oxides such as alumina, magnesium oxide, calcium oxide, beryllium oxide, zirconium oxide, and quartz, and graphite, and at least the inner surface thereof is coated with silicon carbide. Therefore, when vanadium or a compound thereof is dissolved, the amount of impurities mixed from the crucible into the molten metal is reduced, and it becomes possible to carry out melting while maintaining the purity of the melting raw material. In addition, the inner surface of the crucible is less eroded, and the durability is improved accordingly. Therefore, by using the melting crucible of the present invention, it becomes possible to melt at low cost.

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Claims (2)

[Claims] 1. A crucible for melting vanadium and its compound, characterized in that a silicon carbide layer is provided on at least the inner surface of a crucible made of a material other than silicon carbide. 2. The crucible according to claim 1, wherein the material other than silicon carbide is at least one of various oxides such as alumina, magnesium oxide, calcium oxide, beryllium oxide, zirconium oxide, and quartz, and graphite.