JPH02199005A - Apparatus for producing metal oxide - Google Patents

Abstract

PURPOSE:To improve purity of formed powder by providing a coaxial opening of a nonoxidizing gas feed passage between openings for powder and oxygen in an apparatus having a reaction vessel equipped with a specific reaction chamber and respective feed passages for the metal powder, oxygen and an ignition gas. CONSTITUTION:An apparatus composed of a nonoxidizing gas (air) feed passage 3, an oxygen feed passage 4 on the outside thereof, a gas (LPG) feed passage 5, etc., having respective openings coaxial with a powder feed passage 2 opened to a reaction chamber 10. In the above-mentioned apparatus, the metal powder, such as Al, fed to the reaction chamber 10 is prevented from contacting oxygen with the nonoxidizing gas, such as air, fed from an opening 30 therefor and temperature thereof is increased near the opening 20 for the powder by violent combustion. Thereby, the metal powder is prevented from sticking to the vicinity of the opening. The metal powder is further prevented from forming turbulent flows by the nonoxidizing gas flow. Furthermore, the opening 30 for the nonoxidizing gas is formed into a shape extending to the tip thereof to reduce the area of a partition wall of dividing the opening and prevent further sticking. The end face thereof is in the form of an edge to make the sticking difficult. If sticking, the metal powder is readily peeled to stabilize the production.

Description

[Detailed description of the invention] [Industrial Application Field J The present invention relates to an apparatus for producing metal oxides.

The manufacturing apparatus of the present invention can produce metal oxides such as aluminum oxide and magnesium oxide, or mullite, spinel,
It is useful for continuously producing metal composite oxides such as cordierite.

[Prior Art] A manufacturing method proposed by the present inventors is known as a method for continuously manufacturing metal oxides (Japanese Patent Laid-Open No. 63-79
Publication No. 712). In the manufacturing method, a manufacturing apparatus as shown in FIG. 3 is used.

This manufacturing apparatus includes a reaction vessel 100 having a reaction chamber 101, a powder supply path 200 having a powder opening 201 opening in the side wall of the reaction chamber 101 and supplying metal powder together with a carrier gas into the reaction chamber 101, and a powder supply path 200. 200 and a plurality of gas supply passages 300 opening in the side wall concentrically with the powder opening 201, and a collecting device 400.

The powder supply path 200 includes a hopper 20 into which metal powder is charged.
2 is provided, and oxygen gas as a carrier gas is supplied from a valve 203.

The gas supply channel 300 consists of three supply channels provided coaxially with the powder supply channel 200, including an oxygen supply channel 301 provided outside the powder supply channel 200, and an oxygen supply channel 301 provided outside the oxygen supply channel 301. LPG supply path 302, LPG supply path 30
It consists of an air supply path 303 provided on the outside of 2. Each supply path opens concentrically around the powder opening 201.

The collection device 400 includes an exhaust pipe 40 that communicates with the reaction chamber 101.
1 and a dust collector 402 provided at the other end of an exhaust pipe 401, which sucks and exhausts the combustion exhaust gas in the reaction chamber 101 by driving a blower 403, and collects the generated metal oxide powder.

In this manufacturing apparatus, propane gas supplied from the LPG supply path 302 is ignited by an ignition device (not shown) to form a pilot flame. The metal powder supplied from the powder supply path 200 is mixed with oxygen gas as a carrier gas and oxygen gas supplied from the oxygen supply path 301.
It is ignited by a pilot flame to form a combustion flame. This oxidizes the metal powder to form metal oxide powder. This metal oxide powder is collected by a dust collector 11402.

[Problems to be Solved by the Invention] When we carried out an experiment to manufacture metal oxide powder using the above-mentioned manufacturing apparatus, we found that when continuously operated for a long time, the powder opening 201 mainly It became clear that unreacted metals or metal oxides adhered to the surrounding area and gradually grew into icicles. It is presumed that this is because the temperature near the powder opening increases, and the metal powder mainly melts and adheres to it. If the deposits 500 adhere in this way, the combustion flame becomes unstable, the oxidation reaction becomes unstable, and unreacted metal may remain in the collected metal oxide powder. It became clear.

The present invention was made in view of these circumstances, and
The purpose is to prevent deposits from accumulating around the powder opening.

[Means for Solving the Problems] The metal oxide manufacturing apparatus of the present invention includes a reaction vessel having a reaction chamber, and a powder supply path having a powder opening opening in the side wall of the reaction chamber and supplying metal powder into the reaction chamber. an oxygen supply path that is provided coaxially with the powder supply path and has an oxygen opening that opens in the side wall concentrically with the powder opening and supplies oxygen gas into the reaction chamber;
Production of a metal oxide comprising: a gas supply passage provided coaxially with the powder supply passage outside the oxygen supply passage, having a gas opening opening in a side wall concentrically with the powder opening, and supplying ignition gas into a reaction chamber. In the apparatus, a non-oxidizing gas supply path is provided between the powder supply path and the oxygen supply path, and the non-oxidizing gas supply path is provided coaxially with the powder supply path and has a non-oxidizing gas opening opening in the side wall concentrically with the powder opening. It is characterized in that it is configured to supply non-oxidizing gas into the reaction chamber from the oxidizing gas opening.

The reaction vessel has a reaction chamber within which a combustion flame is formed. Since the inside of the reaction chamber reaches a high temperature of 1000° C. or more, its inner surface is usually covered with a heat-resistant and heat-insulating material such as alumina brick.

The powder supply path is a path for supplying metal powder into the reaction chamber, and the metal powder is supplied from a supply source such as a hopper into the reaction chamber through this powder supply path. The metal powder is normally conveyed in the powder supply path by a carrier gas, but it can also be supplied by being dropped by gravity, or it can be conveyed by a conveyor belt or the like.

Incidentally, the carrier gas is generally an inert gas such as nitrogen gas or argon gas, but if 1m gas is used, the oxidation reaction within the reaction chamber can be carried out more efficiently.

Incidentally, the type of metal powder is not particularly limited, such as aluminum, magnesium, and silicon. A single metal oxide may be produced using these metal powders alone, or a composite metal oxide may be produced by simultaneously supplying a plurality of metal powders into the reaction chamber.

An oxygen supply passage is formed coaxially with the powder supply passage outside the powder supply passage. This oxygen supply path has an oxygen opening concentric with the powder opening, and oxygen gas is supplied into the reaction chamber from the oxygen opening.

A gas supply passage is formed coaxially with the powder supply passage outside the oxygen supply passage. This gas supply path has a gas opening concentric with the powder opening, and ignition gas is supplied into the reaction chamber from the gas opening. The ignition gas is ignited in the reaction chamber to form a pilot flame, which has the function of igniting the mixture of oxygen gas and metal powder.

As this ignition gas, hydrocarbon gas such as methane gas and propane gas, carbon oxide gas, etc. are generally used. Depending on the case, liquid fuel such as heavy oil may be sprayed in a gaseous state.

The greatest feature of the present invention is the powder supply path and r! A non-oxidizing gas supply path is provided between the Ii element supply paths, and the non-oxidizing gas opening opening into the reaction chamber of the non-oxidizing gas supply path is located concentrically between the powder opening and the oxygen opening. There it is. With this configuration, the metal powder coming out of the powder opening comes into contact with the oxygen gas and pilot flame supplied from the oxygen opening by the non-oxidizing gas flow from the non-oxidizing gas opening in the vicinity of the powder opening. is prevented. Therefore, combustion flames are prevented from being generated near the powder openings, and the temperature near the powder openings is unlikely to rise, thereby preventing metal powder from adhering to the vicinity of the powder openings. Furthermore, even if deposits try to adhere to the partition wall that separates the powder opening and the non-oxidizing gas opening,
The deposits are blown away by the non-oxidizing gas flow ejected from the non-oxidizing gas opening, thereby preventing deposits from adhering. Note that the non-oxidizing gas as used in the present invention refers to a gas that does not form a combustion flame with the metal powder in the reaction chamber, and includes air as well as inert gases such as nitrogen gas and argon gas.

It is preferable that the non-oxidizing gas opening is constructed so that its diameter increases toward the reaction chamber. In this way, the area of the end face toward the reaction chamber of the partition wall that partitions the non-oxidizing gas opening and the powder opening and the partition wall that partitions the non-oxidizing gas opening and the oxygen opening can be reduced. Therefore, attachment of deposits can be further prevented. Generally speaking, it is preferable that the end face of each partition wall be in an edge shape or a rounded shape rather than being flat. This further makes it difficult for deposits to adhere. In addition, if it is shaped like this,
The volume of that part will become smaller and there is a risk that it will be melted away by the heat of the combustion flame. However, in the case of the present invention, a cooling effect is provided by the non-oxidizing gas, and melting damage is prevented.

The flow rate of the non-oxidizing gas is desirably the same as the flow rate of the powder (the flow rate of the carrier gas) supplied from the powder supply path. This stabilizes the flow of the metal powder within the reaction chamber, thereby further preventing the attachment of deposits and the generation of unreacted materials.

[Operations and Effects of the Invention J] In the metal oxide manufacturing apparatus of the present invention, a non-oxidizing gas is supplied between the powder opening through which metal powder is supplied and the oxygen opening through which oxygen is supplied. A gas opening is interposed. Each aperture is concentric. Therefore, the metal powder supplied into the reaction chamber is prevented from coming into contact with the oxygen gas supplied from the oxygen opening in the vicinity of the powder opening by the non-oxidizing gas flow supplied from the non-oxidizing gas opening.

That is, intense combustion in the vicinity of the powder opening is prevented, thereby preventing the powder opening portion from becoming high temperature, thereby preventing the metal powder from adhering to the vicinity of the powder opening. Furthermore, since the flow of the metal powder is regulated by the non-oxidizing gas flow, the flow of the metal powder is prevented from becoming turbulent and adhesion is also prevented. Furthermore, even if deposits are attached, the non-oxidizing gas flow can be expected to blow away the deposits.

Furthermore, if the non-oxidizing gas openings are shaped such that the diameter increases toward the tip, the area of the end surface of the partition wall that partitions each opening becomes smaller, and adhesion can be further prevented. If this end face is formed into a rounded shape or an edge shape, it is difficult for deposits to adhere to the end face, and even if it does adhere, it is easily peeled off. Note that even if the partition walls are made thin, as described above, intense combustion near the openings is prevented, and the non-oxidizing gas also adds a cooling effect, so that the partition walls are prevented from melting.

In other words, according to the metal oxide manufacturing apparatus of the present invention, since the adhesion of deposits near the powder opening is prevented, a stable combustion flame can be formed even when operated continuously for a long time. This makes it possible to maintain high purity of the metal oxide powder produced.

[Example] Hereinafter, this will be explained in detail using examples.

FIG. 1 shows a schematic configuration explanatory diagram of a metal oxide manufacturing apparatus according to an embodiment of the present invention, and FIG. 2 shows an enlarged cross-sectional view of the main part of FIG. 1.

This manufacturing apparatus includes a reaction vessel 1 having a reaction chamber 10, a powder supply passage 2 provided on the upper side wall of the reaction vessel 1 and opening into the reaction chamber 10, and a reaction chamber 1 provided coaxially with the powder supply passage 2.
an air supply path (non-oxidizing gas supply path) 3 that opens to 0;
An oxygen supply path 4 coaxially provided outside the air supply path 3 and opening into the reaction chamber 10; and an LPG supply path (gas supply path) provided coaxially outside the oxygen supply path 4 and opening into the reaction chamber 10. 5, and a reaction chamber 10 provided on the lower side wall of the reaction vessel 1.
A collecting device 6 communicates with the collecting device 6.

The inner peripheral wall surface of the reaction chamber 10 is made of alumina and has a thickness of about 1 mm.
It is covered with 0 cm of heat insulating material 11.

The volume of this reaction chamber 10 is approximately 50Q.

The powder supply path 2 has a powder opening 20 that opens into the reaction chamber 10, and a hopper 21 is provided at the other end. Oxygen gas as a carrier gas is supplied to this powder supply path 2 from the other end via a valve 22 .

The air supply path 3 has an air opening (non-oxidizing gas opening) 30 that opens into the reaction chamber 10, and air is supplied from the other end via a valve 31. Air opening 30 is formed outside powder opening 20 and concentrically therewith.

The oxygen supply path 4 has an oxygen opening 40 that opens into the reaction chamber 10, and oxygen is supplied from the other end via a valve 41.

Oxygen opening 40 is formed outside air opening 30 and concentrically with powder opening 20 and air opening 30 .

The LPG supply path 5 has an LPG opening (gas opening) 50 that opens into the reaction chamber 10, and propane gas (LPG) is supplied from the other end via a valve 51. LPG opening 50G
, outside the oxygen aperture 40, the powder aperture 20, the air aperture 30
and is formed concentrically with the oxygen opening 40.

The diameter of the air opening 30 increases toward the reaction chamber 10. That is, the partition wall 7 that partitions the air supply path 3 and the powder supply path 2 and the partition wall 8 that partitions the air supply path 3 and the oxygen supply path 4 each have a tapered shape that becomes thinner toward the reaction chamber 10. The tip has a chamfered R shape.

The collection device 6 includes an exhaust pipe 60 that opens into the reaction chamber 10, a dust collector 61 provided at the other end of the exhaust pipe 60, and a blower 62.
By driving the blower 62, the combustion exhaust gas in the reaction chamber 10 is sucked and exhausted, and the generated metal oxide powder is collected.

Using the manufacturing apparatus of this example configured as described above,
Aluminum oxide powder was produced. Note that since aluminum burns violently and the temperature of the combustion flame is high, it is a metal that is particularly likely to adhere to the vicinity of the powder opening.

First, aluminum powder having a particle size of 40 to 50 μm is charged into the hopper 21 . Next, open the valve 51 and supply propane gas from the LPG supply path 5 to the reaction chamber 10 at a rate of 0.4 rl N/
At the same time, the valve 41 is opened to supply oxygen gas to the reaction chamber 10 at a flow rate of 3 ml N/hour.

Then, it is ignited by an ignition means (not shown) to form a pilot flame.

Next, the valve 31 is opened to supply air at a flow rate of 8 m3N/hour, and the valve 22 is opened to supply oxygen gas at a flow rate of 8 m3N/hour.
Aluminum powder is fed at a flow rate of 4 kg/h.

The aluminum powder supplied to the reaction chamber 10 is mixed with oxygen gas and comes into contact with a pilot flame to form a combustion flame. It is then oxidized to form aluminum oxide powder.

Here, since the air flow is ejected from the air opening 30, immediately after coming out from the powder opening 20, the aluminum powder comes into contact with the oxygen gas and pilot flame supplied from the oxygen opening 40 due to the air flow. suppressed. Therefore, the formation of a combustion flame in the vicinity of the powder opening 20 is suppressed, so that the temperature in the vicinity of the powder opening 20 is prevented from increasing. This prevents the aluminum powder from being fused to the surface of the partition wall 7.8 in the vicinity of the powder opening 20.

In addition, the air supplied from the air opening 30 and the powder opening 20
The flow rate is the same as that of the oxygen gas as a carrier gas supplied from the oxygen gas. Therefore, the flow of the aluminum powder directly under the powder opening 20 is regulated and turbulent flow is prevented. This further prevents the aluminum powder and aluminum oxide powder from coming into contact with the surface of the partition wall 7.8, thereby preventing layer adhesion.

Since the tip of the partition wall 7.8 has a tapered shape, the area of the end surface is small. Furthermore, the tip is chamfered in an R shape. Therefore, deposits are less likely to accumulate, and even if they do adhere, they fall off naturally or are blown away by air currents and are easily peeled off.

Therefore, even if aluminum oxide powder is continuously manufactured using the manufacturing apparatus of this embodiment, almost no deposits are observed on the surface of the partition wall 7.8 in the vicinity of the powder opening 20, and stable manufacturing is possible. was completed. It was also observed that even if the deposits adhered, they would naturally peel off after growing for a certain period of time, and would not affect the stability of the combustion flame.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a schematic configuration of a metal oxide manufacturing apparatus according to an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of a main part of FIG. 1. FIG. 3 is a schematic configuration explanatory diagram of a conventional metal oxide production apparatus, and FIG. 4 is an enlarged sectional view of the main part of FIG. 3. 1... Reaction container 2... Powder supply path 3...
Air supply path (non-oxidizing gas supply path) 4... Oxygen supply path 7.8... Partition wall 5... LPG supply path (gas supply path) 10... Reaction chamber 20... Powder opening 30・・・
・Air opening (non-oxidizing gas opening) 40...Oxygen opening 50...LPG opening (gas opening) Figure 1

Claims (1)

[Claims] (1) A reaction vessel having a reaction chamber, a powder supply path having a powder opening opening in the side wall of the reaction chamber and supplying metal powder into the reaction chamber, and the powder opening provided coaxially with the powder supply path. an oxygen supply path that supplies oxygen gas into the reaction chamber and has an oxygen opening opening in the side wall concentrically with the powder supply path; A metal oxide production apparatus comprising: a gas supply path having a gas opening opening in the side wall and supplying ignition gas into the reaction chamber, the powder being disposed between the powder supply path and the oxygen supply path; A non-oxidizing gas supply path is provided coaxially with the supply path and has a non-oxidizing gas opening that opens in the side wall concentrically with the powder opening, and the non-oxidizing gas is supplied from the non-oxidizing gas opening into the reaction chamber. A metal oxide production apparatus characterized in that it is configured to supply.