JPS60128230A - Production of vanadium - Google Patents

Abstract

PURPOSE:To recover vanadium in the form of a mixture composed of metallic vanadium and vanadium carbide at a high yield by maintaining the mixture composed of vanadium oxide and carbon at a high temp. under a vacuum condition. CONSTITUTION:Carbon, for example, graphite powder is mixed with V2O5 which is obtd. by thermal decomposition of, for example, ammonium (meta)vanadate and is generally powder. The material in this stage is preferably of about 30 mesh of finer than said size and the C/V2O5 ratio is preferably about 0.1-5.0. The mixture is made to compact powder and is molded to a briquette, etc. to permit easy putting of said mixture into and out of a hermetic vessel for performing a reduction stage. Such molding is transferred into the hermetic vessel and is held at a high temp. of about >=1,000 deg.C under the vacuum of about <=0.01atm. The V2O5 is then reduced to V and VC and generally the mixture composed thereof is obtd. as the resulted product. If such product is held, for example, at a high temp. of about >=1,000 deg.C for specified time under a vacuum according to need, the product is decarburized.

Description

DETAILED DESCRIPTION OF THE INVENTION OBJECTS OF THE INVENTION The present invention relates to a method for producing metallic vanadium from vanadium oxide, and in particular to a method for producing vanadium by reducing vanadium oxide, such as V2O5, with carbon.

Vanadium is used, for example, in the form of ferrohananium as an additive for high-strength steel and tool steel in the production of special steel used in the steel industry, as well as in electrical materials, superconducting abrasives, and various catalysts. It is an expensive metal that is expected to be in high demand in the future because it is widely used, has a wide range of uses, and is rare.

However, methods for obtaining vanadium in large amounts are limited, and there is a desire to develop an easy method for producing it.

That is, although vanadium is contained in various 6° stones, its content is minute, and it is rare to create high-grade ore deposits like iron, copper, etc. Therefore, in order to obtain vanadium of high purity, ores containing trace amounts of vanadium must be concentrated with great effort. Another method is to obtain vanadium as a by-product when obtaining useful metals from titanium-containing vanadium magnetic steel, uranium, lead, zinc steel, etc., and recently, a method to recover vanadium from oil combustion smoke is also being developed. It is.

As a specific example of vanadium production technology, patent application 1983-1994
There is a method using the Terumi, 1 reaction as disclosed in No. 082 (Japanese Patent Application Laid-open No. 082/1993) and others. This involves recovering vanadium from vanadium-containing resources as ammonium metavanadate, then thermally decomposing it in an oxidizing gas atmosphere to produce vanadium pentoxide (V 20 s ).
Iron powder and aluminum powder are added to this and a thermite reaction is carried out (this is a method to obtain vanadium in the form of ferrovanadium.This method is simple, but in the step of obtaining 2o, thermal decomposition of ammonium salt is The V2O5 generated by the generated ammonia gas is further reduced to V
It is unavoidable that lower oxides such as 2-04 and V 2' Oa are produced as by-products, and the contamination of such lower oxides is
It is not preferred as a raw material for the tilmiso reaction, which requires a large amount of oxygen. Furthermore, in the later stage of the thermite reaction, the reaction itself is violent, making it difficult to control the reaction, and there are also drawbacks such as the scattering of raw materials, which deteriorates the recovery efficiency of vanadium. Therefore, the production of vanadium by the thermite method is still not fully practical.

The present inventors have conducted repeated studies to overcome the drawbacks of conventional vanadium production methods and to find an effective and practical production method. As a result, when vanadium oxide, mainly vanadium pentoxide, which is used in conventional methods, is mixed with carbon and carbon is reduced by keeping it in a closed state under vacuum at high temperature, metal vanadium and vanadium carbide can be combined. The present invention was completed by discovering that vanadium can be recovered in a high yield in the form of a mixture.

(Structure of the Invention) The present invention provides a vanadium source characterized by subjecting vanadium oxide and carbon to fR combination and maintaining this mixture at high temperature under vacuum conditions.According to one aspect of the present invention, ammonium vanadate ((
Vanadium 18 oxide is used by thermal decomposition of Nil4) & VO4) or ammonium metavanadate (Nll<VO3).

According to another aspect of the invention, vanadium oxide and carbon are
The carbon/vanadium oxide M amount ratio is mixed at a ratio of 0.1 to 5.0, and the mixture is heated under vacuum conditions of 0.01 atm or less.
The mixture is maintained at an elevated temperature above 0°C.

According to another aspect of the present invention, the vanadium oxide and carbon to be mixed are both powders of 30 mesh or finer, and the powder mixture is mixed with 50 kg of powder before the reaction.
/ Molded into briquettes or tablenots at a molding pressure of cII+ or higher.

The present invention will be explained in more detail below with respect to its preferred embodiments.

The vanadium oxide used in the present invention may be obtained from any vanadium raw material by any method. However, vanadium oxide and cum are generally produced by thermal decomposition of ammonium vanadate, especially ammonium metavanadate, and it is preferred in the present invention to use vanadium oxide obtained by this method. One example of a vanadium source is ammonium vanadate or ammonium metavanadate recovered from soda ash dephosphorization slag in a steel mill;
When this is heated to about 350"c, vanadium pentoxide (■2°5) is obtained by thermal decomposition. However, as mentioned above, from the ammonia gas produced by the thermal decomposition of ammonium salt, part of the V2O5 produced is The part is V204.V2
Since the reduction progresses to 03, the product also contains such lower oxides. However, unlike the thermite method, the present invention does not require oxygen in the subsequent reduction with carbon, so the coexistence of such lower oxides does not pose any problem in the method of the present invention. As can be seen from the carbon reduction reaction formula described later, ■20. Since the reduction from vanadium to metal vanadium and vanadium carbide proceeds through the state of such lower oxides, the presence of lower oxides can even be said to be preferable.

The vanadium oxide thus obtained is generally in powder form.

This is mixed with carbon, such as graphite 1'5) powder. The material used at this time is preferably 30 mesosinus or finer particles in order to promote the subsequent reduction reaction. If the powder is coarser than 30 mm or 6 mm, the subsequent reduction reaction will be insufficient and vanadium with good purity cannot be obtained. Therefore, if necessary, one or both of the materials may be pulverized, but the pulverization is preferably carried out after mixing the vanadium oxide and carbon from the viewpoint of operational economy and promotion of mixing.

The mixing work of vanadium oxide and carbon is preferably within the range of 0.1 to 5.0 in terms of carbon/vanadium 11 oxide weight ratio. If this ratio is less than 0.1, the amount of reduction will be insufficient and vanadium with good purity will not be recovered. On the other hand, if the mixing ratio is greater than 5.0, the loss of carbon content will increase, which is economically unfavorable.

The thus iS-treated mixture is compacted and shaped into a brigette or cubrenot in order to facilitate its transfer into and out of a closed container in which the reduction process is carried out. The molding pressure at this time is 50 kg/c+d or more, preferably 250 kg/c+d.
cIII or below. At a molding pressure of 50 kg/cnt, it is difficult for the resulting molded product to have sufficient strength to be handled. On the other hand, if molding is performed at a molding pressure exceeding 250 J/aδ, the compression will be too high and the internal reaction will be insufficient, making it difficult to obtain vanadium of high purity, and excessive molding pressure is also unfavorable from an economical point of view.

Next, the molded product is transferred to a closed container and kept under vacuum at a high temperature to perform vanadium oxide removal using carbon. The vacuum condition is 0.01 atmosphere or less.

The direct air condition is to promote the reduction reaction, and the pressure is 0.
．． If the pressure is lower than 0.01 atm, the reduction reaction will not proceed sufficiently. The temperature at which the mixture is maintained is 1000°C or higher. 1000
At temperatures below .degree. C., the reduction reaction does not take place sufficiently and the purity of the vanadium obtained also decreases. The high temperature holding time is not particularly limited, and since the reduction is performed under vacuum, the reduction is completed in a comparatively short time. Generally, the retention time is at least 5 minutes or longer;
It takes about 60 minutes or less.

Reduction of vanadium oxide with carbon generally includes a reaction represented by the following reaction formula: V2O5+ c -→■, O4400■■2O2+ C
-・V 203+C0■V 203 +5 C-・2
V C+ 3 C○ ■V2O3+ C-2VOIc○
■ VO-1-C-→ V1-3 CO■ V 203 + 3 V C→5 v 1-3 CO■
These reactions i, (summarizing V, O!, to Q) metal vanadium and carbide ＼・norsium...
Reduction of L: LIIlIj is expressed by the following two formulas: Reduction to metal vanadium (■, ■, ■ヱ0V205 +
5C-2V 1-5C○ ■Reduction to vanadium carbide (
■,■,■,(■j, 0V 20 s +7 C→ 2
V C-15CO■ Therefore, the final iYI product 1, -p is a mixture of metal halide and sium carbide, containing mostly impurities other than vanadium and carbon. It is of high purity. When the obtained yellowtail is crushed, the product becomes a porous body that is easy to handle.

The obtained product is subjected to post-processing as necessary depending on the intended use. For example, when used as an additive for the production of special εoka in the steel industry, it may be used as is, but
When used as a catalyst, pulverization is necessary to increase the reaction surface. Furthermore, when the product is used in applications where the coexistence of carbon is undesirable, the product can be decarburized, for example, by holding it at a high temperature of about 1000° C. or higher for a certain period of time under vacuum.

The invention will now be illustrated by examples.

Using 50 kg each of vanadium oxide powder obtained by heat-treating 200 kg of ammonium metavanadate recovered from n-sized soda ash slag at about 350° C., the conventional Dermit method and the carbon reduction method of the present invention were tested. A comparative experiment was conducted on the production of vanadium. The vanadium content of the vanadium oxide used was 55.6%, so that 50 kg of this material contained 27.8 kg of Noridium. Also, from this vanadium content,
■The proportion of 205 in the vanadium oxide raw material is approximately 99.2%
it is conceivable that. The experimental conditions and results are shown below.

(11 Thermite method (comparative example) Raw materials: 50 kg of vanadium oxide and 7.5 kg of AQ The above mixture was ignited according to the trial decision, and 7.5 kg of raw material was produced.

Obtained product weight: 62.6 kB Amount of AQ203 in the product: 49.2 Amount of vanadium in the 8 product: 13.4 kg (2) Carbon reduction method (example of the present invention) Raw material vanadium dioxide 5 Q kg and charcoal 5k for Nu
il vacuum conditions: 0.0001 atm high temperature holding conditions: 1650° Cl2O minute product weight: 26.5 kg Vanadium amount in the product: 19.2 kg Carbon amount in the product: 7.3 kg As described above, according to the present invention It is better to reduce it with 4 lead,
Vanadium recovery rate and product quality,'l! l:4k
It was excellent in all aspects (excellence, performance, and performance).

(Effects of the Invention) As detailed above, the product obtained by the present invention contains less impurities such as A(2203) than the product obtained by conventional methods, such as the Thermi yl' reaction. It has high purity and is easy to handle.As for the production method itself, compared to the conventional thermite method, the method of the present invention has less heat loss and the reaction is not violent, making it easier to control the reduction reaction. It is a very simple and practical method for producing vanadium, which is easy and has a high recovery rate of vanadium.Furthermore, the method of the present invention can produce V2O5, which is obtained by the most common method of thermal decomposition of ammonium metavanadate. It is also advantageous in that it can be used without any problem even if lower oxides are present.

Applicant: Sumitomo Metal Industries, Ltd. Agent Patent Attorney Akira Hirose -

Claims (4)

[Claims] (1) A method for producing vanadium, which is characterized by mixing vanadium oxide and carbon and maintaining the mixture at a high temperature under vacuum conditions. (2) The vanadium oxide is converted into j■I by thermal decomposition of ammonium vanadate or ammonium metavanadate.
2. The manufacturing method according to claim 1, wherein the material is vanadium oxide. (3) The ratio of Hernodium oxide to carbon is within the range of 0.1 to 5.0 in terms of weight ratio of carbon/Nonadium oxide;
2. The manufacturing method according to claim 1, wherein said material ('I) is 0.01 atmosphere or less, and said high temperature holding temperature is +000°C or more. (4) The above-mentioned ha/nodium oxide and carbon are both 3
2. The manufacturing method according to claim 1, wherein the powder is a powder of 100 g/ml or finer than that, and the powder mixture is formed into briquettes or tablets at a molding pressure of 50 kg/o11 or more before the reaction.