JP4115136B2 - Method for producing titanium tetrachloride - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an industrially and economically advantageous method for producing titanium tetrachloride that enables a smooth resumption of reaction when the chlorination reaction is stopped in fluid chlorination of titanium-containing ores.
[0002]
[Prior art]
Titanium tetrachloride is widely used as a raw material and catalyst for titanium oxide and titanium metal. Titanium tetrachloride is generally produced by reacting titanium-containing ore and chlorine gas at a high temperature of about 1000 ° C. while flowing in a reactor such as a chlorination furnace in the presence of a reducing agent such as coke. ing. When producing titanium tetrachloride on an industrial scale, it is necessary to temporarily stop the chlorination reaction due to troubles and maintenance of the production plant. While the supply of chlorine gas is stopped and the reaction is stopped, the temperature of the reactor gradually decreases, so the liquefied contents accumulate on the bottom of the reactor and solidify, and chlorine gas is supplied again. However, the fluidity deteriorated, the reactivity was lowered, and in some cases, the fluidized material was not fluidized, and the solidified sediment had to be discharged from the chlorination furnace.
Conventionally, in order to prevent safety measures and oxidation of the contents, purging the inside of the reactor with an inert gas such as nitrogen gas after stopping the supply of chlorine gas. However, with such an inert gas purge, a strong solidified substance is formed, which may hinder the reaction restart.
[0003]
[Problems to be solved by the invention]
The present invention overcomes the problems of the prior art described above, and provides a method for producing titanium tetrachloride that can easily restart the reaction after stopping the chlorination reaction.
[0004]
[Means for Solving the Problems]
As a result of intensive studies to solve these problems, the present inventors may cool the chlorination reaction by supplying an inert gas while maintaining the flow state of the contents in the chlorination furnace. I found out.
[0005]
That is, the present invention is a method of producing titanium tetrachloride by reacting titanium-containing ore and chlorine gas in a fluid state, and when the reaction is stopped by stopping the supply of chlorine gas, the contents in the reactor flow. An inert gas is supplied and cooled so as to maintain the state.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a method for producing titanium tetrachloride, in which titanium tetrachloride is produced by reacting a titanium-containing ore and chlorine gas in a fluid state, and when the reaction is stopped by stopping the supply of chlorine gas. The reactor is cooled by supplying an inert gas so that the contents in the reactor are maintained in a fluid state. The contents cooled while maintaining the fluid state hardly consolidate, or even if solidified, they do not produce a strong solidified substance or stick to the reactor. It quickly returns to a fluid state and titanium tetrachloride can be produced. In the present invention, the supply of the inert gas may be continued until the chlorine gas is supplied again. However, the supply of the inert gas may be stopped when the cooling proceeds to some extent.
[0007]
In order to maintain the flow state of the contents in the reactor after the reaction is stopped, the supply of chlorine gas is stopped and then an inert gas is supplied to the reactor. In order to confirm the flow state inside the reactor, it is industrially carried out by measuring the pressure difference between the upper and lower parts of the fluidized bed. In the present invention, the above pressure difference during the supply of the inert gas, That is, the pressure difference measured at P1 and P2 shown in FIG. 1 is preferably in the range of 5 to 50 kPa, and more preferably in the range of 10 to 30 kPa. The inert gas for maintaining the fluid state is preferably supplied at a flow rate in the range of 3 to 30 cm / second, more preferably in the range of 10 to 20 cm / second. When the flow rate is lower than 3 cm / sec, it is difficult to achieve a sufficient fluid state and cooling is difficult to proceed. Further, even if the flow velocity is increased from 30 cm / second, no further effect can be obtained, which is not economical. The period during which the inert gas is supplied is preferably until the temperature of the contents has decreased by at least 20 ° C. from the start of the supply of the inert gas, and more preferably by continuing to supply until the temperature has decreased by at least 30 ° C.
[0008]
Examples of the inert gas used in the present invention include nitrogen gas, argon gas, carbon dioxide gas, and the like, but since nitrogen gas is particularly inexpensive, it is industrially preferable. There is no particular limitation on the reactor, and the present invention can be applied to those of various configurations, shapes, and sizes. For example, there is no fluid chlorination furnace having a porous dispersion disk at the bottom, or a porous dispersion disk. It can be used for an injection type flow chlorination furnace or the like, and it is preferable to use it for a thing having a porous dispersion disk at the bottom, since it also prevents the chlorine gas supply port from being blocked. Moreover, there is no restriction | limiting also in a titanium containing ore, Well-known things, such as an ilmenite ore, a rutile ore, anatase ore, titanium slag, a synthetic rutile, or those mixtures, can be used. In particular, the production method of the present invention is useful when using, as a raw material, a titanium-containing ore containing a large amount of impurities that easily form a consolidated product. As such a titanium-containing ore, for example, an alkaline earth such as calcium is used. An example is titanium slag containing a large amount of metal.
[0009]
【Example】
Examples of the present invention are shown below, but the present invention is not limited thereto.
[0010]
Example 1
In the presence of coke, a mixture of titanium slag and synthetic rutile (contains 0.10% calcium as CaO) and chlorine gas is reacted in a fluid chlorination furnace at a temperature of 1050 ° C. Manufactured. After the supply of chlorine gas was stopped, nitrogen gas was supplied to the chlorination furnace at a flow rate of 15 cm / second, and the contents were cooled while maintaining a fluid state. The pressure difference between the upper part and lower part (P1, P2 in FIG. 1) of the fluidized bed during supply of nitrogen gas was 20 kPa, and the temperature of the contents one hour after the start of nitrogen gas supply was 1000 ° C. Then, when nitrogen gas was stopped and chlorine gas was supplied, the reaction could be resumed in a good fluidized state due to the pressure difference between the upper and lower surfaces of the fluidized bed. Thereafter, the reaction was stopped and restarted as necessary by the same method, but no particular problem was observed, and the operation of the chlorination furnace was continued for one year.
[0011]
Comparative Example 1
The same procedure as in Example 1 was performed except that the flow rate of nitrogen gas was changed to 1 cm / second. The pressure difference between the upper and lower contents corresponding to P1 and P2 in FIG. 1 during the supply of nitrogen gas is 1.0 kPa, and it is estimated that the contents did not flow. The temperature of the contents one hour after the start of nitrogen gas supply was 1040 ° C. Thereafter, when the reaction was repeatedly stopped and restarted as necessary by the same method, the chlorination furnace could not be operated because the flow of the contents in the chlorination furnace occurred 60 days after the first reaction was resumed. It became. When the chlorination furnace was opened after the reaction was stopped, a solidified deposit was formed inside, and this was discharged and the operation was resumed.
[0012]
【The invention's effect】
The present invention, in a method for producing titanium tetrachloride by fluid chlorination of titanium-containing ore, enables smooth resumption of the reaction after temporarily stopping the chlorination reaction, and in particular, impurities as a raw material. This is useful when using a large amount of titanium-containing ore.
[Brief description of the drawings]
[Fig.1] An example of fluidized chlorination furnace [Explanation of symbols]
1 Flow Chlorination Furnace 2 Titanium-containing Ore Inlet 3 Gas Supply Port 4 Outlet 5 Upper Pressure Measuring End (P1)
6 Lower pressure measurement end (P2)

Claims (5)

In a method for producing titanium tetrachloride by reacting a titanium-containing ore containing at least 0.10% of an alkaline earth metal in terms of oxide and chlorine gas in a reactor in a fluid state, the supply is stopped by stopping the supply of chlorine gas. When the process is stopped, an inert gas is supplied and cooled so that the contents in the reactor maintain a fluid state, thereby preventing the formation of a solidified product . The method for producing titanium tetrachloride according to claim 1, wherein the inert gas is supplied at a flow rate in the range of 3 to 30 cm / sec. The method for producing titanium tetrachloride according to claim 1, wherein the inert gas is supplied so that the differential pressure between the upper part and the lower part of the fluidized bed is in the range of 5 to 50 kPa. 2. The method for producing titanium tetrachloride according to claim 1, wherein the inert gas is supplied until the temperature of the contents decreases by at least 20 [deg.] C. from the start of the supply of the inert gas. 2. The method for producing titanium tetrachloride according to claim 1, wherein the inert gas is nitrogen gas.

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