JPH0741880A - Cooling method and device for sponge titanium reducing furnace - Google Patents

Abstract

PURPOSE:To improve productivity in production of so-called crawl method sponge titanium to produce the sponge titanium by dropping titanium tetrachloride into a molten magnesium bath. CONSTITUTION:A mixture composed of air and misty water drops s blown to the upper part of the outside wall of a reaction vessel to cool the vessel at the time of producing the spongy metal titanium 1 by dropping the titanium tetrachloride 3 from above the molten metal magnesium bath 2 charged into the heated reaction vessel 9. A water injection nozzle 8 connected to a flow rate control mechanism 6 is mounted at a piping for blowing air for cooling the outside walls of the reaction vessel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for cooling a reaction vessel in the so-called Kroll method sponge titanium for producing titanium sponge by dropping titanium tetrachloride into a molten metal magnesium bath.

[0002]

2. Description of the Related Art In the titanium sponge production method by the Kroll method, a stainless steel reaction vessel is placed in a heated furnace,
Molten magnesium is charged inside, titanium tetrachloride is dropped in a static state in an inert atmosphere, and titanium tetrachloride is reduced by magnesium to produce titanium sponge.
Following this reduction step, a sponge titanium block is manufactured through a separation step of magnesium metal and magnesium chloride and a cooling step.

Since the reduction reaction of titanium tetrachloride with magnesium is accompanied by heat generation, the temperature of the outer wall of the reaction vessel, which corresponds to the upper surface of the magnesium bath, is controlled by blowing air. However, since the cooling capacity of air cooling is small,
In order to protect the inner and outer walls of the reaction vessel, the dropping rate of titanium tetrachloride has to be reduced, which causes a problem of low productivity in the reduction step. Further, since the temperature of the inner wall of the reaction vessel is high, the generated titanium sponge reacts with the vessel, and there is a problem that the life of the vessel is shortened due to melting damage of the vessel and the surface of the titanium sponge mass is contaminated.

[0004]

SUMMARY OF THE INVENTION The object of the present invention is to prevent a decrease in productivity, which is a problem in the reduction step of the sponge titanium production process, and to produce a sponge titanium block having less surface contamination. The present invention provides a method of cooling a titanium sponge reduction furnace and a titanium sponge reduction furnace having the cooling mechanism.

[0005]

The gist of the present invention is to produce sponge-like metallic titanium by dropping titanium tetrachloride from above a molten magnesium metal bath charged in a heated reaction vessel. At the time of cooling, a method of cooling the titanium sponge reduction furnace characterized by spraying a mixture of air and mist-like water droplets onto the upper portion of the outer wall of the reaction vessel to cool it, and a reaction vessel and a heating furnace for heating the reaction vessel In the cooling device of the sponge titanium reduction furnace, which is composed of piping for blowing cooling air on the outer wall of the reaction vessel of the titanium sponge reduction furnace, a water injection nozzle connected to the flow rate control mechanism was attached to the piping for blowing air for cooling the outer wall of the reaction vessel. A cooling device for a sponge titanium reduction furnace, which is capable of spraying a mixture of air and water droplets on the outer wall of a reaction vessel. The details of the present invention will be described below together with the operation.

[0006]

In order to remarkably increase the cooling capacity of the outer wall of the reaction vessel, in the present invention, a mixture of air and atomized water is sprayed instead of the air used in the conventional method. In the present invention, the mixing ratio of air and water is 0.03 by weight.
~ 0.2 is suitable. Water has an extremely large cooling capacity compared to air, but it is ineffective if the amount of water contained is small. As a result of the experiment, the lower limit of the mixing ratio at which the effect is recognized is 0.03. If the amount of water mixed is too large, the cooling will be too strong and the reaction in the furnace will become unstable, and the quality of titanium sponge will deteriorate. Also,
The water sprayed on the outer wall of the reaction vessel flows down along the outer wall, lowers the temperature of the heating section below the vessel, and significantly deteriorates the quality of titanium sponge. At this time, the fuel consumption of the heating furnace also increases. The upper limit of the mixing ratio at which water does not flow down is 0.2
Met.

Since the cooling air after cooling contains a large amount of water vapor, drain water is produced when cooled to a temperature below the dew point in the discharge path. Therefore, consideration must be given to providing drainage drains in the cooling air discharge path such as the piping section. The cooling capacity is controlled by measuring the temperature in the reaction vessel or the outer wall of the vessel. As a cooling capacity control means, the flow rate of water mixed with air is controlled. That is, when the temperature is higher than the set value, the amount of water is increased, and when the temperature is lower, the amount of water is decreased.

A conceptual diagram of the titanium sponge manufacturing apparatus of the present invention is schematically shown in FIG. That is, in the conventional Kroll method titanium sponge production apparatus, a mixer (water injection nozzle) 7 is provided in the cooling air blowing air pipe 5 on the outer wall of the titanium sponge production reaction vessel 9 to inject the cooling water 6 whose flow rate is controlled. A mixture of water and air is created and sprayed onto the upper surface of the metal magnesium bath 2 in the container 1 through the spray port 8. In the figure, 1 is titanium sponge, 3 is titanium tetrachloride to be dropped, 4
Is a vacuum system and 10 is a heating furnace.

[0009]

EXAMPLE A 1.2 ton molten magnesium was charged into a stainless steel reactor having an inner diameter of 800 mm, and the temperature was raised to 8
Titanium tetrachloride was dripped at a rate of 2.6 kg per minute from a dropping tube provided at the center of the upper lid while maintaining the temperature at 00 ° C. In the upper part of the heating furnace, inwardly-discharging nozzles with 24 nozzles arranged at equal intervals are installed in three stages in the height direction, and water is supplied from the nozzles whose height corresponds to the change in height of the upper surface of the metal magnesium bath during operation. A / air mixture was sprayed onto the outer wall of the reaction vessel.

The control temperature is 150 mm in the height direction on the outer wall of the container.
It was measured by a thermocouple embedded at intervals. The air / water mixture ratio was adjusted so that the thermocouple indicated 660 ° C. The air / water mixture ratio during operation was in the range of 0.06 to 0.14. After 25 hours, the supply of titanium tetrachloride was stopped, the temperature was raised to 1020 ° C., and the vacuum separation process was started. After 36 hours from the vacuum separation step, the heating of the furnace was stopped under an argon gas atmosphere, and the cooling step was started. After 32 hours, since it was sufficiently cooled, 1012 kg of a mass of titanium sponge was taken out from the reaction vessel and supplied to the crushing step.

As a comparison, in the standard method in which water is not mixed with cooling air, a reduction step of 40 hours (titanium tetrachloride average dropping rate of 1.7 kg / min) and a vacuum are performed in order to obtain 1 ton of titanium sponge mass under the same temperature and pressure conditions. Separation process 36 hours, cooling process 3
It took 2 hours. Therefore, the present invention increased the productivity by 1.6 times in the reduction process and 1.16 times in the whole process. The surface peeling thickness of the titanium sponge lump in the crushing step was 0.8 mm on average, which was halved from the average value of 1.5 mm of the titanium sponge lump by the standard method. The quality of sponge titanium after crushing was as good as that of titanium sponge prepared by the standard method in terms of density and amount of impurities. The reduction in the reaction vessel wall thickness after use was 0.12 mm, which was 60% of the standard method.

[0012]

According to the present invention, the productivity of titanium sponge is increased especially in the reduction step, the yield of titanium sponge ingot is improved, and the life of the reaction vessel is extended.

[Brief description of drawings]

FIG. 1 is an explanatory view schematically showing the outline of an apparatus for carrying out the method of the present invention.

[Explanation of symbols]

 1 Titanium Sponge 2 Molten Magnesium 3 Titanium Tetrachloride 4 Vacuum System 5 Cooling Air 6 Cooling Water Flow Control Mechanism 7 Mixer 8 Cooling Fluid Spray Port 9 Reaction Vessel 10 Heating Furnace

Claims (2)

[Claims] 1. When producing titanium metal sponge by dropping titanium tetrachloride from above a molten metal magnesium bath charged in a heated reaction vessel, a mixture of air and mist-like water droplets is added. A method for cooling a titanium sponge reduction furnace, characterized by spraying onto the outer wall of the reaction vessel to cool. 2. A sponge titanium reduction furnace having a reaction vessel and a heating furnace for heating the reaction vessel and having a pipe for blowing cooling air to the outer wall of the reaction vessel. A cooling device for a titanium sponge reduction furnace, wherein a water injection nozzle connected to a flow rate control mechanism is attached to the pipe.