JPS61141622A - Production of lower oxide of vanadium - Google Patents

Abstract

PURPOSE:To produce V2O3 safely, by contacting one or more kinds of V compounds having higher oxygen content than V2O3 with NH3 gas at a specific molar ratio under specific partial pressure, and keeping the system within a specific temperature range for a specific time interval. CONSTITUTION:For example, V2O5 is put into the stainless steel mesh container 11 in the reaction furnace 10 from a hopper, and NH3 gas is circulated to the reaction furnace through the pipe line 12. The molar ratio of the Nh3 gas to V2O5 is 1-20, and the partial pressure of the NH3 gas is 0.1-1.5atm. The reaction furnace 10 is heated at 450-700 deg.C with a heater for 1-6hr, and the V2O5 is decomposed and reduced to V2O3. The produced V2O3 is circulated through the pipe line 14 and cooled with the cooling cylinder 13.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] This invention relates to a method for producing 2o from a vanadium compound having a higher oxygen content than vanadium trioxide (VzOa).

In recent years, V2O3 has been used as a material for temperature sensors and other alloy manufacturing.
It is used as a catalyst.

[Prior art]

Conventionally, as a method for obtaining V2O3 from the vanadium compound, a method was disclosed in JP-A-49-47294 in which ammonium metavanazidate (NH, VO, It is also heated to 650-1000''C in an exhaust-tight container without contact with vanadium pentoxide (Vies) and magnesium (NHP) or aluminum (NH).
A method for obtaining 20a has been published in Japanese Patent Application Laid-open No. 72894/1983.

However, since the former method uses H2 gas, there is a risk of explosion if it leaks or if oxygen gets mixed into the reactor, and it is also extremely expensive, increasing product costs and being impractical.

In addition, since the latter method uses exhaust gas sealed heating, a large container cannot be used, the amount that can be manufactured at one time is limited, manufacturing is discontinuous, and a special heating furnace is required for manufacturing.

[Problem to be solved]

This invention does not use explosive gas like the conventional technology,
Another object of the present invention is to provide a method that can safely employ ammonia (NH3) gas without requiring a sealed container and that can be used in both batch and continuous methods.

[Means for solving problems]

This invention uses one or more vanadium compounds with a higher oxygen content than divanadium trioxide (V, O,) as a raw material, and adds ammonia (NH3) gas in a molar ratio of 1 to 20 times to this raw material. Contact with the raw materials at a partial pressure of 0.1 to 1.5 arm, and set the reaction temperature to 450 to 700'C.
It was held for ~6 hours to resolve the decomposition of the raw material.

[Embodiment]

Next, embodiments of the present invention will be described.

As a raw material for this invention, metavanadate an-F-y
(NH4VO3) Using one or a mixture of two or more vanadium compounds having a higher oxygen content than V2O3, such as vanadium pentoxide (V2O,)-vanadium dioxide (VO2), and NH3 at a molar ratio of 1 to 20 times. This raw material is brought into contact with a gas flow at a reaction temperature of 450 to 700°C, and the partial pressure of NH3 gas in the reaction vessel is adjusted to 0.1 to 1.
5 atm (the rest being nitrogen (N2) gas or other inert gas) for 1 to 6 hours, the raw material is decomposed and reduced to produce V2O3, and then an inert gas such as nitrogen gas at room temperature is heated. This is continuously supplied and cooled to obtain the target product.

〔effect〕

When the product obtained by the above method was examined by X-ray diffraction, the results were as shown in Figure 1-1, which agreed well with the results of the conventional reduction method using N2 gas.
It was identified as O3.

It is easy to use, and the heating temperature is relatively low at 450 to 700"C, so the reaction vessel, gas supply pipe, etc.
There is no particular limitation as long as it can withstand this level of temperature, and inexpensive materials such as steel pipes and stainless steel pipes can be used.

In addition, the reactor can be used to collect sugar and gas in a one-shot system or in a circulation system, and the reactor itself can be isolated from the outside air for the time being (as in the method using H, 2 gas). Compared to the conventional method, which requires 15 to 20 hours for reaction time, the reaction time is shorter at 1 to 6 hours, and the process is continuous without the need for special furnaces and labor that are vacuum-sealed each time. Processing can also be performed, improving productivity.

In this invention, if the amount of NH3 is less than 1 times the molar ratio of the vanadium compound, the reduction will not proceed sufficiently, and if it is more than 20 times, the product will tend to contain N and is not economical.

Furthermore, if the reaction temperature is below 450°C, the reduction will not proceed sufficiently;
At temperatures above 700°C, N is easily included in the product (and is not economical).

In addition, if the partial pressure of NI (3 gases) is less than 0.1 arm, the reduction will not proceed sufficiently, and if it is more than 1.5 arm, the product will likely contain N, and a pressurizing device will be required, which will increase the product cost and be uneconomical. .

In this invention, the reason why one or a mixture of two or more vanadium compounds having a higher oxygen content than V2O3 can be used as a raw material as described above is because the reaction is thought to be based on the following process.

[Experiment example]

Experimental Example 1 As a raw material, 30g of NH4VO3 was placed in a stainless steel net container (diameter 22MII, length 150ar), and this was loaded into a ring furnace. After replacing the inside of the furnace with N2 gas, the gas was circulated. After the temperature of the reaction section reaches the predetermined temperature 4
After holding the temperature for a period of time to cause a reduction reaction, N2
The mixture was cooled to room temperature by flowing gas (see Table 1 (1), (2), and (3)).

Experimental example 2 Vanadium pentoxide V, O5 was used as a raw material.

(See Table 1, (4)) Table 1 Both methods could be identified as ■203 by X@ diffraction. [See Figure 1] [Comparative experiment] Next, as a comparative experiment, the reaction temperature was outside the limited range of the molar ratio of NH3 gas to raw material, and the conventional hydrogen gas and N2 gas were used as reducing agents as shown in Table 2. It was shown to.

Table 2 In Table 2, examples (5), (6) and (7)
H4vO3 was used. For example (8), conventional N2 gas was used as the reducing agent.

As an example of an apparatus, a device like that shown in Figure 3 is used.In Figure 1, 10 is a reactor, in which a stainless steel mesh container 11 is installed, and a pipeline 12 connects the reactor 10 to the reactor. This is so that NH and gas can be circulated and N2 gas can be supplied. 13 is a cooling cylinder;
This is for cooling the product and allows N2 gas to be circulated by pipeline 14.

[Brief explanation of drawings]

The drawings relate to this invention; Figure 1 is an X-ray diffraction diagram of the product obtained by the method of the present invention, Figures 1 and 2 are X-ray diffraction diagrams of the product reduced by conventional N2 gas, spear 3
The figure is a schematic diagram of an apparatus used in the present method invention. Patent applicant: Shinko Kagaku Kogyo Co., Ltd. Planar spacing (dA) Planar spacing (dA)

Claims (1)

[Claims] Using one or more vanadium compounds with a higher oxygen content than divanadium trioxide (V_2O_3) as a raw material,
For this raw material, 1 to 20 times the molar ratio of ammonia (N
H_3) The gas is brought into contact with the raw material at a partial pressure of 0.1 to 1.5 atm, and the reaction temperature is maintained at 450 to 700°C for 1 to 6 hours to decompose and reduce the raw material to generate V_2O_3. A method for producing lower vanadium oxides.