RU2549795C2 - Method of producing titanium and apparatus therefor - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: disclosed is a method of producing titanium via reduction thereof from a tetrachloride using a liquid tetrachloride and dispersed aluminium as a reducing agent. The process is carried out in the temperature range of -23°C to +137°C and weight ratio of the initial titanium tetrachloride to aluminium of not less than 5.27 to 1.00 with intense mixing. The system is kept in a pseudo-Newtonian liquid state by using highly dispersed initial aluminium and dispersed products - titanium and aluminium tetrachloride with relative excess of the liquid phase. An apparatus for implementing the method is a flat-bottom conical reactor mounted on a magnetic mixer and fitted with batchers for feeding tetrachloride and dispersed aluminium, as well as a device for separating suspensions of titanium, aluminium trichloride and titanium tetrachloride. The latter is returned to the reactor and solid phases are separated by sublimation and subsequent condensation of aluminium trichloride. Powdered titanium is fed for further processing.

EFFECT: simple technique owing to lowering of temperature.

2 cl, 1 dwg

Description

Technical field

The invention relates to the metallurgy of non-ferrous metals in relation to the technology for producing titanium.

State of the art

It is known that in modern conditions for the production of titanium, its gaseous tetrachloride is used, which is reduced by metallic magnesium [1] or sodium [2, 3] in an inert gas atmosphere — drained argon or helium [3, p.247]. The named inventions should be considered as the main analogues of our technical solution. In this case, the closest prototype is a magnesium thermal process for the reduction of titanium from its tetrachloride. Moreover, in the first case, the reaction proceeds: $$$$

$$$$

$$TiC{l}_{\mathrm{four}g}+2M{g}_{\mathrm{well}(g)}=T{i}_{t\mathrm{at}}+2M\mathrm{<figure-callout\; id="2"\; label="g\; C\; l"\; filenames="00000004.png"\; state="\{\{state\}\}">g\; </figure-callout>}C{l}_{}{}_{2\mathrm{well}}\text{(one)}$$

Magnesium is loaded into a reactor heated to 800 ° C [3, p.245]. The reactor is vacuumized before being installed in the furnace, but then the pressure in it is raised to 0.05-0.1 at. The process requires the provision of very complex temperature conditions. The temperature in the center of the reactor can reach more than 1000 ° C. At the end of the recovery process, hold for 30-60 minutes at 900 ° C, after which the final discharge of magnesium chloride is performed and the reactor is cooled to 800 ° C or 600 ° C. Further cooling to 20-40 ° C is carried out on a special stand, where the reactor is cooled with water or blown with air.

To extract the reaction mass from the cooled reactor, it is drilled on special machines [1, p. 258]. The titanium sponge ultimately obtained requires tremendous labor to free it from dissolved gases and transfer titanium to the plastic state necessary for the production of sheets, profiles, pipes, etc. from it. Titanium production processes are very complex, laborious, energy intensive and it seems desirable to find simpler ways in metallothermal processes for producing this metal.

SUMMARY OF THE INVENTION

It consists in the fact that due to the use of titanium tetrachloride not in a gaseous but in a liquid-phase state, to simplify the process and reduce energy and labor costs. The temperature range of the liquid state of titanium tetrachloride is very large and extends from -23 ° C to + 136-138 ° C, i.e. equal to 160 ° or 1.6 times wider than the liquid-phase state of water (!). At room temperature, TiCl ₄ is a mobile liquid with a density of ~ 1.73 g / cm ³ and a viscosity of ~ 0.0083 poise, i.e. even slightly lower viscosity of water [3, p.130].

The second feature of the proposed invention is that instead of magnesium, aluminum is used as a metal reducing agent, the cost of which in recent years at the London Metal Exchange has fluctuated between $ 1800-2500, and magnesium about $ 3000 per ton.

The essence of the recovery process instead of reaction (1) is then expressed by the equation:

. $$3TiC{l}_{\mathrm{four}\mathrm{well}}+\mathrm{four}A{l}_{t\mathrm{at}}=3T{i}_{t\mathrm{at}}+\mathrm{four}AlC{l}_{3t\mathrm{at}}\text{(2)}$$

.

According to reaction (1), four phases are used: gaseous tetrachloride, liquid (or partially gaseous) magnesium to produce solid titanium and liquid magnesium chloride with five components (including an inert gas).

In our invention, according to reaction (2), vacuum and four phases are applied - one liquid and three solid, i.e. only two types of phase states, while in the classical process according to reaction (1) there are three types of phase states. In the described invention, four components are used instead of five in the prototype invention. Finally, the solid phases are represented by the initial finely dispersed aluminum, and also not prone to sintering by powdered titanium and aluminum chloride at low temperatures. Therefore, in our invention, a sponge will not form, the processing of which requires enormous labor and energy costs.

Process (2) is thermodynamically possible and seems simpler, less energy- and labor-intensive, but provided that it is possible to overcome kinetic barriers. The first of them relates to the need to introduce aluminum in a finely dispersed state in the form of a powder or powder with particle sizes of 1 μm or less with the largest possible specific surface area. And such aluminum is produced in the workshops of the agro-industrial complex (aluminum powders and paints) at the former Irkutsk, Bogoslovsky, Volgograd and other plants, but does not find sufficient demand.

The second kinetic barrier is an oxide film on the surface of aluminum particles. However, the production of aluminum finely dispersed powders in the workshops of the agro-industrial complex is carried out in vacuum or under conditions of carefully dried and inert gas that does not contain oxygen and moisture. The oxide film on the metal particles is therefore absent.

Fine aluminum powder-powder or granular metal with small granule sizes can behave like a fluidized medium.

Obtained at low temperatures (-23 ° - + 137 ° C), titanium and aluminum chloride are also in a finely divided state. Therefore, with relatively small mass or volume contents of solid phases, the system as a whole will remain in the state of a pseudo-Newtonian fluid.

In order to avoid its transfer into rheological structures, it is necessary, in addition to using some excess of liquid tetrachloride, to apply magnetic stirring and to ensure the optimal temperature regime of the process.

Obviously, this regimen should fit into the liquid state range of titanium tetrachloride from -23 ° C to + 137 ° C. With relatively low contents of dispersed solid phases and with an excess of tetrachloride, the entire system is in a fluidized state.

The process according to reaction (2) is carried out at a mass ratio of the starting titanium tetrachloride and dispersed aluminum of not less than 5.27 to 1.00. The upper limit and the optimal value of this ratio are determined experimentally.

To carry out the process, a metal or lined with resistant materials reactor is used that reproduces in shape a conical flat-bottomed flask placed on a magnetic stirrer.

The technical result of the process

It consists in simplifying the recovery technology by lowering the temperature from 800-900 ° C and above to -23 ° - + 137 ° C in the preparation of dispersed products that do not form a sponge and are easier to process. For the same reasons, a significant reduction in energy and labor costs for titanium production is expected. Finally, thanks to the use of aluminum as a cheaper metal reducing agent instead of magnesium, the cost of raw materials will be lower. Due to the reduction in the number of components and phases employed in the process, as well as due to the properties of the fluidized dispersed phases, the new technology is easier to automate.

List of figures of drawings and description of interaction

Figure 1 shows a vertical section of a device for implementing the invention. The basis of the device is a reactor 1 made of mild steel or other materials resistant to liquid titanium tetrachloride. The reactor is mounted on a magnetic stirrer 2, the stirring element 3 of which is made of ferromagnetic metal and enclosed in a protective sheath of resistant polyvinyl chloride materials. Dispersed aluminum powder or “powder” 2 is introduced into the reactor from the metering unit 4 in flow 5. Titanium tetrachloride is fed into the reactor from the metering unit 6 in flow 7.

The resulting mixture of solid-phase powdered titanium and aluminum trichloride suspended in liquid titanium tetrachloride flows downstream into the apparatus 8 for settling and filtering the liquid phase. Next, titanium tetrachloride is returned to the reactor, aluminum trichloride from the filters is transferred to the gas phase by sublimation at ~ 180 ° C, and then, upon cooling in an inert atmosphere or taste, a crystalline commercial product is obtained. Solid phase dispersed titanium from the filters is subjected to further processing.

To ensure that the system is in a fluidized state, the magnetic stirrer is equipped with a device 10 for heating or cooling the contents of the reactor. The reactor through a pipe 11 is connected to a vacuum line.

The device can operate both in batch and continuous modes when controlling and regulating the mass flow rates of the feed streams of titanium tetrachloride and dispersed aluminum, as well as in the processing of products of titanium and aluminum trichloride.

Information confirming the possibility of carrying out the invention

The invention is based on several indisputable facts bestowed upon us by nature. This is the existence of titanium tetrachloride in the form of a mobile Newtonian fluid in a large low-temperature range, relatively close to the range of existence of liquid water. This is the possibility of using aluminum for the reduction of titanium from tetrachloride, which L. Pauling referred to [4, p. 482] (of course, without specifying the phase states of the reaction participants, temperatures, and other conditions). Finally, it is the availability of ready-made technology and production facilities for producing aluminum as a reducing agent in the form of a dispersed powder or powder. One can add, as an obvious statement, that at low temperatures it is much easier to process fine powders of aluminum, titanium and aluminum trichloride than to produce titanium at high temperatures, to cool and further process conglomerates such as a titanium sponge.

Literature

1. Kroll W.J. Pat. USA No. 2.205.854, 1940.

Kroll W.J. Trans Electrochem. Soc. 1940, v. 78, p. 25.

2. Kirillov D.V. Research on titanium. - Publishing house typogr. Arkhipova, 1875.

3. Garmata V.A. et al. Metallurgy of titanium. - M.: Metallurgy, 1968, 643 p.

4. Pauling L. General chemistry. - M., 1974, 838 p., P. 482.

(Linus Pauling. General chemistry. Third edition. - San-Francisco, 1970).

Claims (2)

1. A method of producing titanium, comprising reducing titanium tetrachloride with a reducing metal in a vacuum, characterized in that dispersed aluminum with a particle size of 1 μm or less is used as a reducing metal, which is introduced into a reactor with liquid titanium tetrachloride at a temperature of from -23 ° C to + 137 ° C and a mass ratio of the initial titanium tetrachloride and aluminum tetrachloride of not less than 5.27 to 1.00, to obtain reduction products in the form of powdered titanium and aluminum trichloride suspended in titanium tetrachloride in the form of pseudony tonic liquid, which is removed from the reactor, is separated by filtration into a solid phase in the form of powdered titanium and aluminum trichloride and liquid titanium tetrachloride, which is returned to the reactor, while aluminum trichloride from the filter is transferred to the gas phase by sublimation and subsequent condensation into a solid product, and powder titanium is sent for further processing. 2. A device for producing titanium, containing a reactor with a vacuum pipe, characterized in that the reactor is made in the form of a flat-bottomed cone with a stirring element of ferromagnetic metal, mounted on a magnetic stirrer and has a dispenser for feeding liquid titanium tetrachloride, a dispenser for introducing dispersed aluminum and a flow for draining reduction products in the apparatus for separating solid and liquid phases by settling and filtration, while the magnetic stirrer is equipped with a device for heating and cooling the contents in torus.

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