JPS6410580B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for producing titanium metal by reacting titanium tetrachloride and a reducing metal in a reaction zone at a temperature higher than the melting point of the reducing metal and the chloride of the reducing metal. Regarding the improvement of

Conventionally, the so-called Hunter method, Kroll method, etc. are known as methods for producing the above-mentioned titanium metal.
For example, in the Kroll method, before the start of the reaction, solid or molten magnesium, which is a reducing metal, is charged into a retort-like reaction vessel (if solid magnesium is used, it is further heated,
After raising the temperature to a temperature at which it can react with titanium tetrachloride),
Liquid titanium tetrachloride is reacted while being dropped into the reaction vessel, and the temperature of the reaction part is maintained at a temperature higher than the melting point (715°C) of magnesium chloride produced together with metallic titanium by reaction heat and/or external heating. Perform the reaction while doing so.

Since the melting point of metallic magnesium is 650°C, metallic magnesium is also a molten body at the above temperature. In order for the titanium tetrachloride dropped from the top of the reactor to react smoothly and rapidly, it is necessary that the surface formed by both the magnesium and magnesium chloride melts (hereinafter simply referred to as the melt surface) contain magnesium instead of magnesium chloride. The presence and direct contact with the dropped titanium tetrachloride is an essential requirement.
Since the specific gravity of molten magnesium is lower than that of molten magnesium chloride, generally at least in the early stage of the reaction, magnesium chloride sinks below the molten layer, and the molten magnesium layer floats above it, and the molten surface is mainly made up of magnesium. The reaction proceeds smoothly and rapidly. Incidentally, since the titanium produced by the reaction is heavier than both magnesium and magnesium chloride melts, it settles on the bottom of the reaction vessel and forms a spongy layer (hereinafter this layer is referred to as a spongy titanium layer).

Since the sum of the increase in the volume of magnesium chloride and the increase in the volume of titanium as the reaction progresses is much larger than the decrease in volume due to consumption of magnesium, the total volume of the contents in the reactor increases as the reaction progresses. It is necessary to increase the amount of titanium produced per volume of the reactor, that is, the volumetric efficiency of the reactor, in order to improve productivity, and for this purpose, the magnesium chloride produced during the reaction process is Alternatively, it may be necessary to continuously extract the material from the container.

As the reaction progresses, the deposited layer of metallic titanium (sponge-like) gradually grows upwards, but in order to keep the reaction progress (reaction rate) fast, the contact between magnesium and titanium tetrachloride must be maintained. It is necessary to have good melting, and for this reason it is preferable that the surface of the magnesium layer be located above the titanium sponge layer. If the surface of the magnesium layer is located at a significantly lower level than the titanium sponge layer, the titanium tetrachloride must penetrate through the pores of the titanium sponge before contacting and reacting with the magnesium, resulting in an extremely slow reaction rate.

Therefore, it is necessary to calculate and determine the above-mentioned extraction timing and extraction amount of magnesium chloride so that the surface of the magnesium layer floating on the magnesium chloride layer is near or above the surface of the titanium sponge layer. However, even if the position of the magnesium layer surface is adjusted in this way, the magnesium chloride produced by the reaction on the magnesium surface will descend through the pores of the titanium sponge layer, and the magnesium will rise through the pores of the titanium sponge layer. Must.

In this way, the substitution of magnesium and magnesium chloride must be carried out through the pores of the sponge titanium layer, so as the deposited layer of sponge titanium grows, the rate of substitution between the two decreases. A situation occurs in which the magnesium layer, which should be floating above or near it, remains in the sponge titanium layer, and instead, the magnesium chloride, which should be precipitated, floats above the sponge titanium layer. Under such conditions, titanium tetrachloride cannot of course come into contact with magnesium and the reaction stops.

The reaction is carried out by appropriately selecting the shape of the reactor, the amount of magnesium charged, the timing and amount of magnesium chloride to be extracted, etc., in order to maximize the efficiency of operation such as the volumetric efficiency of the reactor, reaction rate, and utilization rate of magnesium. Even if the amount of magnesium is reduced, for example, when about 60% of the amount of magnesium charged has reacted, the substitution of magnesium and magnesium chloride usually begins to deteriorate and the reaction rate begins to decrease. The problem of a reduction in the reaction rate in the latter stage of the reaction due to poor substitution of magnesium and magnesium chloride can be cited as the first drawback of the conventional method.

Another reason why magnesium cannot float and the reaction stops is that magnesium is trapped in the pores of the spongy titanium sediment layer and cannot float to the surface of the solution. In other words, the reaction between magnesium and titanium tetrachloride takes place near the magnesium surface, and the titanium sponge formed at this location gradually settles to the bottom of the vessel. Even if the magnesium contained in the pores of this sponge is well replaced with magnesium chloride, it cannot float to the surface, resulting in a loss that cannot react with titanium tetrachloride. This is a major reason why in the conventional method, the reaction amount relative to the initially charged amount of magnesium, that is, the magnesium utilization rate, cannot be improved beyond about 70 to 80%. The problem of low magnesium utilization can be cited as the second drawback of the conventional method.

Next, in the early stage of the reaction in the conventional method, the magnesium layer is in a state where it can come into good contact with titanium tetrachloride, so by increasing the dropping rate of titanium tetrachloride, the reaction rate itself can be increased almost without limit. When the reaction rate is increased, the reaction between magnesium and titanium tetrachloride generates a large amount of reaction heat, and the temperature of the reactor rises extremely quickly. Reactor walls are usually made of iron or iron-based alloys for economic reasons, but the eutectic point of titanium and iron is approximately
Since the temperature is 1050°C, if the temperature of the reactor wall exceeds this temperature, the reactor wall and the titanium produced will undergo eutectic melting. Rapid reaction rates leading to exotherms above this temperature cannot therefore be carried out. This restriction on the reaction rate at the initial stage of the reaction can be cited as the third drawback of the conventional method.

The present invention was made in order to improve the drawbacks of such conventional methods, and it does not reduce the reaction rate in the late stage of the reaction as seen in conventional methods, and can significantly shorten the reaction time. It is an object of the present invention to provide a method for producing titanium metal, which can reduce the energy required for the reaction, has a high utilization rate of reducing metals, and allows easy adjustment of the reaction temperature.

That is, the present invention provides a method for producing titanium metal by causing titanium chloride and a reducing metal to react in a reaction zone at a temperature higher than the melting point of the reducing metal and the chloride of the reducing metal. Immediately after the start of the reaction, a small proportion of the reducing metal in an amount necessary to reach the desired reaction rate is fed into the zone and melted, and then the titanium chloride and the remaining main proportion of the reducing metal are added. Provided is a method for producing metallic titanium, characterized in that the reaction is carried out while continuously or continuously supplying a powdery solid to the melting surface of the reaction zone from above the reaction zone directly in small amounts. .

The titanium chloride used in the present invention is selected from titanium tetrachloride alone, or a mixture of titanium tetrachloride and one or two of titanium trichloride and titanium dichloride.

Titanium tetrachloride alone is preferred in terms of reactivity, reaction rate, handling, etc. A mixture of titanium tetrachloride and other chlorides is preferred because the reaction temperature can be more easily controlled.

Examples of reducing metals used in the present invention include magnesium, sodium, lithium, potassium, calcium, etc., with magnesium being the most preferred.

When supplying titanium chloride and reducing metal to the reaction zone, there are no particular restrictions as long as the contact between the two can be made good and the reaction can be carried out quickly, but titanium chloride and reducing metals can be supplied directly to the melt surface from above the reaction zone. It is preferable that the reaction can be carried out smoothly and quickly.

Before feeding the titanium chloride and the granular solid of the reducing metal to the reaction zone to start the reaction, a portion of the reducing metal or a mixture thereof with a chloride of the reducing metal is charged to the reaction zone. In this case, it is possible to reach a predetermined reaction rate immediately after the start of the reaction, which is preferable.

When feeding titanium chloride and reducing metal granular solids to the reaction zone, they can be fed continuously or continuously depending on the reaction conditions, or they can be fed separately and directly. Alternatively, both may be mixed and then supplied. When both are supplied separately, the granular solid of the reducing metal may be supplied for a part of the entire reaction period that is arbitrarily selected depending on the reaction conditions. When supplying both after mixing, the mixture may be supplied for a part of the entire reaction period that is arbitrarily selected depending on the reaction conditions, and only titanium chloride may be supplied for the remaining period. Furthermore, when supplying both after mixing, for example, when the titanium chloride is titanium tetrachloride and the reducing metal is magnesium, the specific gravity of both at room temperature is approximately equal, so storage tanks, supply piping, flow meters, etc. for both, etc. This is advantageous in that both can be made common, and both can be uniformly mixed without being separated and unevenly distributed.

The particle size of the reducing metal powder/grain solid used in the present invention is so large that it becomes difficult to feed it into the reaction vessel, or it becomes difficult to feed it into the reaction zone and then dissolves. There is no particular restriction as long as the temperature distribution in the reaction zone does not locally become significantly non-uniform due to heat absorption, and the shape and size of the reaction vessel,
A method for supplying reducible metals and titanium chloride,
Although it should be determined appropriately in relation to the supply rate and the like, it is usually preferably in the range of 10 μm to 10 mm.

When the particle size is larger than the above upper limit, it becomes difficult to supply the particles to the reaction vessel, and the temperature distribution in the reaction zone becomes non-uniform, which is not preferable.

If the particle size is 10 μm or less, there is no problem in theory from the point of view of the reaction itself, but it is impractical because it requires special refinement means, and if it is supplied separately from titanium chloride, the reaction It is difficult to supply the band.

According to the method of the present invention, the reaction is carried out while supplying titanium chloride and the reducing metal directly to the melt surface from above the reaction zone, so there is no reduction in the reaction rate, and the reaction time is greatly shortened. Productivity can be increased. For example, in the reaction between titanium tetrachloride and magnesium, especially in the late stage of the reaction,
There is no need for magnesium to replace magnesium chloride and float to the surface of the solution for the reaction.

In addition, since the reaction progresses rapidly while titanium chloride and reducing metals are directly supplied to the molten surface above the titanium sponge layer, the amount of reducing metals that are trapped in the pores of the titanium sponge layer and do not contribute to the reaction is reduced. Therefore, the utilization rate of reducing metals is greatly increased.

According to the method of the present invention, the reducing metal is directly supplied as a solid to the reaction zone, so the heat content is lower than that in the molten state of the conventional method, and the temperature rise due to the reaction heat is alleviated. This has the effect of significantly increasing the amount of reaction per hour, that is, productivity. For example, solid magnesium has a reaction temperature of
For example, compared to molten magnesium at 1000°C, its heat content is lower by about 8.7 Kcal/mol, which is about 31.4 Kcal/mol of the reaction temperature per mol of magnesium in the reaction of titanium tetrachloride and magnesium at 1000°C. This corresponds to 28%. Therefore, the third drawback of the conventional method, the restriction on the reaction rate caused by avoiding the temperature rise due to the heat of reaction, is reduced by an amount corresponding to the difference in the heat content of magnesium. In other words, if the amount of heat dissipated from the reaction vessel remains the same, the reaction rate can be increased by 28%. As a result of being able to increase the reaction rate, productivity can be increased and energy consumption can be significantly reduced.

The present invention will be specifically explained below using Examples.

Example 1 A titanium tetrachloride supply pipe was installed through the center of the upper lid of a reaction vessel in which a steel inner cylinder was set in a stainless steel outer cylinder container, and a magnesium grain supply pipe was installed immediately next to it. Titanium sponge was manufactured using a reduction reaction device that can electrically heat the outer cylinder.

Put 600kg of molten magnesium into the outer cylinder and heat to 800℃.
Heat to temperature. When the temperature reached 800℃, titanium tetrachloride was added from the titanium tetrachloride supply pipe at a rate of 2100 c.c./min, and at the same time, magnesium particles (particle size 2 to 4 mm) were added from the magnesium grain supply pipe in an amount equivalent to the reaction equivalent.
Start feeding each at a speed of 926g/min,
Without changing the feeding rate of titanium tetrachloride and magnesium particles midway through, the feeding of both was finished in 31.5 hours, yielding 1726 kg of titanium sponge. The reaction temperature was 1000°C, and the excess Mg was 1.35.
The production amount of titanium sponge per unit time is 54.8
It was Kg/hr.

Comparative Example 1 Using a reaction vessel of the same scale as in Example 1, titanium sponge was produced by a conventional method as described below. First, before starting the reaction, determine the total amount of magnesium required for the reaction.
After charging 2200 kg into a reaction vessel and raising the temperature to 800°C, titanium tetrachloride was supplied at a rate of 1000 to 2100 c.c./min for 42 hours, and the reaction was carried out at 1000°C to form titanium sponge.
Obtained 1500Kg. The Mg excess rate is 1.47, and the production amount of titanium sponge per unit time is 35.7Kg/hr.
It was hot.

Example 2 A steel reaction vessel was set inside a stainless steel outer cylinder. A supply pipe for a mixture of titanium tetrachloride and magnesium particles was installed through the center of the upper lid of the reaction vessel, and electrical heating was applied from outside the outer cylinder. Titanium sponge was manufactured using a reduction reaction device that can be used.

A mixture of titanium tetrachloride and magnesium particles to be used in the reaction is placed in a tank at a ratio of 1 mole of titanium tetrachloride and 2 moles of magnesium particles, and stirred with a stirrer so that the titanium tetrachloride and magnesium particles do not separate.

600Kg of molten magnesium is charged into the outer cylinder.
Heat to 800℃. When the temperature reaches 800°C, the mixture of titanium tetrachloride and magnesium particles in the tank is fed into the reaction vessel from the supply pipe at a rate of 2100 c.c./min as titanium tetrachloride and 926 g/min as magnesium particles. . The difference in specific gravity between titanium tetrachloride and magnesium particles is 0.014 at room temperature, so the magnesium particles do not settle and are supplied with the same composition as in the tank.

31.5 hours after the start of the reaction, the supply of titanium tetrachloride and magnesium particles was completed, and 1733 kg of titanium sponge was obtained.

The reaction temperature was 1000°C, and the excess Mg was 1.34. The production amount of titanium sponge per unit time was 54.8 Kg/hr.

Claims (1)

[Claims] 1. A method for producing titanium metal by reacting a titanium chloride and a reducing metal in a reaction zone at a temperature higher than the melting point of the reducing metal and the chloride of the reducing metal. Immediately after the start of the reaction, a small proportion of reducing metal is supplied to the reaction zone in an amount necessary to reach a predetermined reaction rate, and then melted. 1. A method for producing metallic titanium, which comprises reacting with a powdery solid in a small amount continuously or continuously from above the reaction zone directly onto the melting surface of the reaction zone. 2. The method for producing titanium metal according to claim 1, wherein the titanium chloride is titanium tetrachloride. 3. The method for producing titanium metal according to claim 1, wherein the titanium chloride is a mixture of titanium tetrachloride and one or two selected from titanium trichloride and titanium dichloride. 4. The method for producing titanium metal according to claim 1, wherein the reducing metal is magnesium. 5. Claims 1 to 5 in which the titanium chloride and the reducible metal granular solid are separately supplied to the reaction zone.
The method for producing titanium metal according to any one of Item 4. 6. Claim 1 of supplying titanium chloride and a granular solid of a reducing metal to a reaction zone after mixing them.
The method for producing titanium metal according to any one of items 1 to 4. 7. The method for producing titanium metal according to claim 5, wherein the granular solid of the reducing metal is supplied for an arbitrarily selected portion of the entire reaction period. 8 The mixture of titanium chloride and reducible metal granular solid was randomly selected during the entire reaction period.
7. The method for producing titanium metal according to claim 6, wherein titanium chloride is supplied for a period of 10 minutes, and only titanium chloride is supplied for the remaining period. 9 The particle size of the powdery solid of the reducing metal is 10 μm or more.
A method for manufacturing titanium metal according to any one of claims 1 and 4 to 8, wherein the thickness is in the range of 10 mm.