JP3482426B2 - Method for producing titanium tetrachloride - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing titanium tetrachloride from titanium ore as a raw material.

[0002]

Titanium tetrachloride is widely used as an intermediate product for producing titanium sponge and the like. Titanium tetrachloride is currently used for titanium ores such as rutile, ilmenite, synthetic rutile, chlorine gas and coke at 900-
It is manufactured by supplying to a fluidized furnace kept at 1100 ° C. to cause the reaction of TiO ₂ + 2Cl ₂ + (1-2) · C = TiCl ₄ + 2CO / CO ₂ ··· (3).

In this case, the raw material is required to have an appropriate particle size range in order to stably perform the flow and the reaction. In general, raw coke is crushed and sieved, and granular coke adjusted to the particle size range required for operation of the fluidized furnace is supplied together with titanium ore from the raw material supply hopper at the upper part of the fluidized furnace to the gas space in the fluidized furnace. Is done in a way.

In order to efficiently produce titanium tetrachloride in this fluidized furnace, the following is desired. Increase the yield in the process of producing coke that can be supplied from the raw coke to the fluidized furnace, and lower the unit cost of coke. The coke supplied to the fluidized furnace should be used effectively with the least amount of scattering. Minimize coke wear other than those used for ore reduction reaction (for example, blowing air, oxygen, etc. to oxidize to raise temperature). Increase fluidized bed productivity as much as possible. However, since the equation (3) is an exothermic reaction, when the temperature in the furnace rises above a predetermined value, a measure to reduce the chlorine supply amount is usually taken. In that case, since the productivity will be reduced as a result, it is desirable to control the temperature without such side effects.

The coke particle size range, which is conventionally preferable for the operation of a fluidized furnace, is probably empirical.
Generally, fine powder having a particle size of 150 μm or less scatters out of the reaction system together with the generated gas in the furnace, which not only contributes to the reaction, but also has a problem that it takes time and effort to remove it. As a method for avoiding this problem, JP-A-1-188424
In Japanese Patent Laid-Open Publication No. 2005-242242, a calcined coke, which is substantially spherical particles, is used, and a preferable particle size range for supplying the coke to a fluidized furnace is about 150 to 5000 μm, particularly preferably about 4 μm.
It is assumed to be 25 to 3000 μm.

However, one of the factors that raises the unit cost of coke is that the amount of loss in producing such a particle size range is so large that it cannot be ignored. Further, even if the particle size is adjusted in this way, there is still a large amount of coke scattered from the fluidized furnace, further, in the conventional method of supplying coke from the raw material hopper above the fluidized furnace to the gas space in the furnace,
Since the supplied coke grain size cannot be controlled over time, there is also a problem in that the operation results are deteriorated due to the temperature adjustment. Therefore, the conventional method has a limit in reducing the unit cost of coke, improving the yield, and improving the productivity of the fluidized furnace.

[0007]

In view of the above circumstances, an object of the present invention is to provide a coke which can be used in a method for producing titanium tetrachloride by supplying titanium ore, chlorine gas and coke to a fluidized furnace. A method for reducing the unit price by expanding the particle size range, suppressing coke scattering to improve the yield, and stably controlling the temperature inside the furnace, which was a constraint when improving productivity. It is a thing.

[0008]

In order to achieve such an object, the present invention was obtained as a result of experimentally examining various conditions of coke grain size and usage of coke for each grain size. That is, the present invention provides (1) a fluidized furnace with titanium ore, chlorine gas and 150 μm.
by supplying granular coke m~5mm a process for the preparation of titanium tetrachloride, in addition to the supply of the granular coke,
A method for producing titanium tetrachloride, characterized in that powdery coke having a size of 297 μm or less is directly supplied into a fluidized bed so as to satisfy the following formulas (1) and (2) . When the measurement temperature is higher than 980 ° C, powder coke supply rate (Kg / h) / chlorine gas supply rate (Nm ³ / h) = 0.0002 (measurement temperature (° C) -980) to 0.0015 (measurement temperature (° C) -960) (1) When the measured temperature is 980 ° C or lower Powder coke supply rate (Kg / h) / chlorine gas supply rate (Nm ³ / h) = 0 to 0.0015 (Measurement temperature (° C) -960) (2) (2) Powdered coke is directly supplied into a fluidized bed together with at least one of inert gas and chlorine gas. The gist is the method for producing titanium tetrachloride described in 1).

[0009]

The present invention will be described in detail below with reference to a specific method of implementation. First, various investigations were performed by changing the operating conditions in a fluidized bed reactor for producing titanium tetrachloride, and the following results were obtained. (1) Regarding the coke, the particle size of each of the coke existing in the furnace and that scattered was found to be 100
It was found that a particle size of 180 μm or less is the limit particle size. (2) It was found that, for powdery coke having a size of 105 μm or less, the scattering ratio was significantly different between the case where it was supplied from above the gas space of the fluidized furnace and the case where it was supplied directly using an inert gas in the fluidized bed. . That is, in the case of the former, the rate of scattering without reaction was 91%, whereas in the case of the latter, it was 38%. (3) Regarding the particle size of the powdery coke when directly supplied to the fluidized bed, an experiment was conducted under various conditions.
It was found that if the thickness exceeds μm, the supply pipe is likely to be worn. (4) When powdery coke having a particle size of 297 μm or less is directly supplied to a fluidized bed using an inert gas, CO ₂ / C of the gas is obtained.
O ratio decreases. That is, the calorific value is reduced and the temperature inside the furnace is reduced. (5) The amount of scattered coke decreases as the amount of coke in the furnace decreases, but unreacted chlorine becomes detected in the exhaust gas when the amount of coke is 3 wt% or less. In this state, if powdered coke of 297 μm or less is blown into the fluidized furnace, free chlorine will not be detected in the exhaust gas.

The present invention was obtained based on the above findings. First, the raw material coke is crushed and sieved to obtain granular coke and powder coke having a desired particle size. In the conventional method, only granular coke was supplied to the fluidized furnace together with titanium ore (usually from the upper side through the gas space above the fluidized bed), and powdered coke was not used for the production of titanium tetrachloride. . On the other hand, in the present invention, in addition to supplying the granular coke in the same manner as the conventional method, by supplying the powdery coke in a form of directly blowing into the fluidized bed corresponding to the temperature measured in the furnace, the coke The temperature of the furnace is controlled stably as well as being prevented from scattering.

FIG. 1 or 2 shows a schematic view of the equipment used in the present invention. Here, the fluidized furnace 1 is a device for performing a reaction, the fluidized bed 2 is a layer in which solid raw materials are in a fluidized state in the furnace, the gas space s is a product in a gaseous state, and the volume ratio of solids is 3
% Or less space. Chlorine gas is blown from the bottom through the dispersion plate 6. The granular coke is supplied to the gas space s from the supply port 3 through the raw material hopper (not shown) together with the titanium ore. The temperature in the furnace is measured by the thermocouple 4 at the position shown in the figure.

A feature of the present invention is that the position where the powdery coke is supplied is not in the gas space s in the furnace but in the fluidized bed, and FIG.
The provision of the supply port 5 as shown in FIG. From here, an inert gas such as nitrogen is constantly blown in, and the powdery coke is supplied in correspondence with the measurement temperature in the furnace by using this inert gas as a carrier gas. In addition,
The powdery coke may be supplied from the side surface as shown in FIG. 1, or may be supplied from the bottom through the dispersion plate 6 together with chlorine gas. In addition, it is also possible to use a movable supply pipe 7 as shown in FIG. 2 so that the tip of the pipe enters the fluidized bed only when coke is supplied.

In the operation, the supply amount of powdery coke is adjusted as follows. The temperature in the furnace is continuously measured, and if the measured temperature is higher than 980 ° C., powder coke is blown so as to satisfy the condition shown in the formula (1). Powder coke supply rate (Kg / h) / chlorine gas supply rate (Nm ³ / h) = 0.0002 (measurement temperature (° C) -980) to 0.0015 (measurement temperature (° C) -960) ...・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ( 1) When the temperature is 980 ° C. or lower, the powdery coke is blown according to the formula (2). Powder coke supply rate (Kg / h) / chlorine gas supply rate (Nm ³ / h) = 0 to 0.0015 (measurement temperature (° C) -960) (2) Also, by keeping the amount of coke present in the furnace at 15 wt% or less, it is possible to reduce the scattering loss and to find that free chlorine tends to be generated in the exhaust gas in that state. The supply of powder coke according to the above method is 0.017 to 0.0
By blowing at a rate of 89 kg / h · chlorine gas supply (Nm ³ / h), it is possible to quickly stop the generation of free chlorine. By such a method, it becomes possible to reduce the unit cost of coke, reduce the amount of scattered coke, increase the chlorine supply amount, and simultaneously improve the productivity of the fluidized bed.

[0014]

Example 1 Titanium tetrachloride was produced using titanium ore (rutile), coke and chlorine gas using the apparatus shown in FIG. The coke was crushed and sieved with 80 mesh to obtain granular and powdery coke. Table 1 shows the particle size distribution and components of each.

[0015]

[Table 1]

The operation of the fluidized bed furnace is as follows. Chlorine gas supply rate; average 564 Nm ³ / h Titanium ore supply rate; average 1110 Kg / h Granular coke supply rate; average 227 Kg / h Powdery coke was supplied into the fluidized bed using nitrogen gas by the method shown in FIG. 1. The relationship between the change in furnace temperature and the supply amount of powdery coke was set so as to satisfy the expressions (1) and (2). The average feed rate of powder coke was 28 kg / h. Based on this, the temperature in the furnace could be stably adjusted between 1010 and 1030 ° C. while keeping the chlorine supply rate constant.

[0017]

Example 2 Using the apparatus shown in FIG. 2, except that the powdery coke having the particle size distribution shown in Table 2 (the composition is the same as in Example 1) was fed into the fluidized bed by the method shown in FIG. Titanium tetrachloride was produced using the same raw materials as in Example 1.

[0018]

[Table 2]

The operating conditions of the fluidized furnace are as follows. Chlorine gas supply rate; average 564 Nm ³ / h Titanium ore supply rate; average 1110 Kg / h Granular coke supply rate; average 250 Kg / h Powdery coke was supplied into the fluidized bed using nitrogen gas.
The average feeding rate of the powder coke was 31 kg / h. Based on this, while keeping the chlorine supply rate constant, the temperature inside the furnace could be stabilized and controlled between 1000 and 1030 ° C.

The operation result of each of the above-mentioned examples is shown by a particle size of 297 μm.
As described above, as compared with the case of the conventional method in which the coke having the same composition as that of the example is added from above, the results are as shown in Table 3, which shows that the temperature fluctuation range is reduced and the coke unit consumption is reduced without decreasing the production rate. It was possible to reduce.

[0021]

[Table 3]

[0022]

EFFECTS OF THE INVENTION By implementing the present invention, it becomes possible to efficiently produce titanium tetrachloride in a fluidized furnace (reduction of cost of coke used, improvement of temperature adjustment accuracy, improvement of productivity, etc.). The industrial effect is extremely large.

[Brief description of drawings]

FIG. 1 is a schematic explanatory diagram of an example of an apparatus used to carry out the present invention.

FIG. 2 is a schematic explanatory view of another example of a device used for implementing the present invention.

[Explanation of symbols]

1 Flow furnace 2 fluidized bed 3 Granular coke, ore supply port 4 thermocouple 5 Powder coke supply port 6 Dispersion plate 7 Powder coke supply pipe s gas space

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) C22B 1/00-61/00

Claims (2)

(57) [Claims] 1. A fluidized furnace containing titanium ore, chlorine gas and
A method for producing titanium tetrachloride particulate coke is supplied to 150Myuemu～5mm, in addition to the supply of the granular coke, the following equation (1), 297Myu to satisfy (2)
A method for producing titanium tetrachloride, characterized in that powdery coke having a size of m or less is directly supplied into a fluidized bed. When the measurement temperature is higher than 980 ° C, powder coke supply rate (Kg / h) / chlorine gas supply rate (Nm ³ / h) = 0.0002 (measurement temperature (° C) -980) to 0.0015 (measurement temperature (° C) -960) (1) When the measured temperature is 980 ° C or lower Powder coke supply rate (Kg / h) / chlorine gas supply rate (Nm ³ / h) = 0 to 0.0015 (Measurement temperature (℃) -960) ... (2) 2. The method for producing titanium tetrachloride according to claim 1, wherein the powdery coke is directly supplied into the fluidized bed together with at least one of inert gas and chlorine gas.