KR101491891B1 - Method for producing aluminium by metallothermic reduction of trichloride with magnesium and apparatus for carrying out said method - Google Patents

Abstract

A method for receiving aluminum by metal thermal magnesium recovery of aluminum trichloride in a flow of inert gas at a temperature of 900 DEG C to 1150 DEG C and at a total pressure of 0.01 to 5 atm is provided and the mass correlation of aluminum chloride and magnesium in the parent mixture is 3.69: 1.00. The process is realized in a cylindrical reactor with a thin walled attachment 6 made of ceramic and located inside the reactor. The reactor is provided with a conical bottom portion. Evaporator of the magnesium in the flow of inert gas is mounted in front of the reactor and there is a unit for separating the liquid magnesium from the residual mixture of magnesium and aluminum chloride behind the reactor, Lt; / RTI > Technical results are growing in return for a guaranteed continuous process of recycling and the best ecological characteristics.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing aluminum by heat recovery of aluminum trichloride using magnesium,

FIELD OF THE INVENTION The present invention relates to non-ferrous metallurgy, and more particularly to aluminum production technology.

In non-ferrous metallurgy, the so-called Heroult-Hall process, which is the electrolysis of cryolitho-alumina melt, is used to produce aluminum. Electrochemical devices and cells are characterized by a rather low factor of indication of the useful volume consumed, especially when the work is to be registered only on the surface of the electrode-electrolyte, not all through the entire volume of the reactor in chemical technology.

Only one electrode, the cathode, is responsible for the overall amount of useful work performed when the process is performed according to Er-Hall's methodology. As a result, cells are characterized by rather low productivity per cell, with only 3-4 tons per 24 hour cycle. Thus, a plant that produces aluminum has hundreds and thousands of cells that occupy vast areas and consume significant investment while being dried.

The cell is not sealed by the structural features of the cell and the whole process is carried out in the form of natrii, aluminum and hydrogenii fluorides, carcinogenic polyaromatics compounds, alternative greenhouse gases, carbon dioxide and especially perfluorocarbons perfluorinecarbon) into the atmosphere. All of the above is taken into consideration and the production of aluminum by electrolysis of the chloryl-aluminum melts is considerably outdated, because of the frequency of occurrence of aluminum in the Earth's crust (the leading place among the metals) Because it does not correspond to a unique set of structural and technical properties.

There was a conventional solution to the problem of aluminum containment based on the metal thermal methodology by recovery with potassium from aluminum chloride (F. Wohler, 1828) or sodium (S'K. Deville, 1854) according to the scheme:

AlCl ₃ + 3M = 3MCl + Al (1),

Here, M is an alkali metal.

However, when an alkali metal is used corresponding to Scheme 1, metal and power consumption is very high. When associated with potassium, 4.33 kg of alkali metal and 35 kW / h of power are consumed to recover 1 kg of aluminum. For sodium, 2,555 kg of metal and 25,5 kw / h of power are required to recover 1 kg of aluminum.

For other common and similar methods, yen. N. Beketov's proposal is the most real proposal. Accordingly, aluminum can be accommodated through the recovery of aluminum by magnesium from aluminum fluoride or cryolite, which is a component of Greenlandic cryolithionite.

_{2 (3NaF x AlF 3) +} 3Mg = 6NaF + 3MgF 2 + 2Al (2).

Fluoride is a more difficult to process compound, and the devices as well as the process of recovery are more complicated to implement this method. In addition, the unique deposits of Greenlandic Cryolite emanate from the time of the 19th century.

The closest standard for this method is the production of metallic titanium as a result of the recovery of metallic titanium by metal magnesium from tetrachloride.

TiCl ₄ + 2 Mg = ₂ MgCl ₂ + Ti (3)

Since this process involves the introduction of titanii chlorides with different valences into the reaction, the relationship of the reaction is different between the aggregates in different states: gaseous titanium chloride, magnesii chloride and magnesium as liquids, It is in titanium. As a result, this method often requires decompression of the apparatus in order to reduce the productivity of the process and to extract titanium, which degrades the ecological properties.

Crawl W. J. (Kroll W.J.) United States No. 2205854 1940

Crawl W. J. (Kroll W.J.) Trans. Electrochem. Soc., 1940, vol. 78, p. 35. V. a. V.A. Garmata et al., ≪ / RTI > M. (Metallurgia titana. M.), Metallurgia, 1968, 643 s. a. yen. A. N. Zelichman, J. a. G.A. Meerson. Metallurgia redkich metallov, M., Metallurgia, 1973, 607 c. Spravotchnik chemica // Pod red. Blood p. B.P. Nikolskogo, t II, Chemia, M., 1964, 1168 s. M. M. Giua, Istoria chemie, Mir, M., 1975, 477 s. M. M. M. Vetukov, A.. M. A. M. Tsiplakov, S. < RTI ID = 0.0 > yen. S.N. Schkolnicov. Electromataglia alumina eye magnetia. M. (trometallurgia aluminia i magnia. M.), Metallurgia, 1987, 320 s K. K. Grjotheim, Queue. Q. Zhuxian. En Salt Technology, VII, Shenyang, China, 1991, 435. V. a. V. A. Lebedev, V. I. V.I. Sedykh. Metallurgia magnia, Irkutsk, 2010, 175 pp. a. children. A. I. Begunov. Problems modernizathii aluminum electrolizerov, Irkutsk, 2000, 105 s.  Crawl W. J. (Kroll W.J.) Trans. Electrochem. Soc., 1947, No. 89, p. 41  Crawl W. Kroll W. J. Metalls, 1955, vol. 5, pp. 9-10, p. 336.  V. blood. V.P. Mashovets. Electrolizerov aluminia. ONTI-NKTP, SSSR, 1938, 345 pp.

The technical result of introducing the present invention is a higher ecological property by providing higher productivity and device seal by the continuity of the recovery process.

Technically, this object is met by utilizing the reaction of the metal heat recovery of aluminum trichloride by magnesium.

2AlCl _{3 (g)} + 3Mg _(g) = 3MgCl _{2 (1)} + 2Al ₍₁₎

Here, << g >> is a gas phase display while << l >> is a liquid state display. Thus, according to Scheme (4), the parent substance is introduced as a gaseous substance as a process and the resulting product, which is aluminum and magnesium chloride, is released as molten liquid material. The recovery is carried out with a flow of inert gas at a temperature of 900 ° C to 1150 ° C and a total pressure of 0.01 to 5 atm. The proportion of aluminum chloride and metal magnesium mass in the initial mixture is correspondingly 3.69 to 1.00. In this case, the consumption of magnesium would be 1.35 kg per 1 kg of aluminum, while the power requirement for the electrolyte magnesium would be about 17.9 kW / h per kg of aluminum. The result is further improved when magnesium, which is housed in a metal-heated manner, is used, i.e. magnesium, which is initially recovered from dolomite by ferrosilicon according to Pidgeon's technique (V. VALebedev, V., VISedykh, Metallurgy of Magnesium, Irkutsk, 2010, p. 149). According to reaction (4), the total consumption of energy in this case will not exceed 13 kWh per kg of aluminum, which is similar to the consumed value for the method of Er-hole, which is very useful in the stage of generating magnesium- Can be considered as an indication.

However, recovery of aluminum from trichloride by magnesium according to scheme (4) is an independent scientific and engineering problem. Reaction formula (4), which is the basis of the present invention, is realized much simpler than Reaction formula (3) as a standard for the magnesium-thermal recovery of titanium. However, it can be seen as ironic, but higher temperatures and pressures are required to produce aluminum as a result of the recovery of aluminum from trichloride to magnesium.

Actually, as the recovering agent, magnesium has a boiling point temperature of 1103 캜 to 1107 캜 (the pressure of steam forms 1 atm), and the melting temperature of magnesium is 651 캜. For the other participant in scheme (4), aluminum melts at 660 ° C. A particularly wide range of liquid states is for aluminum with a boiling point of 2497 ° C. Aluminum does not actually evaporate at the boiling point of magnesium (1107 ° C). Magnesium chloride melts at 708 캜 to 714 캜 and boils at a temperature of 1412 캜 to 1417 캜 to have a liquid state in a relatively wide temperature range. And finally, the aluminum trichloride can sublimate at a temperature of 179.7 ° C and not be present in a liquid state at normal atmospheric pressure. Thus, parent substances, namely aluminum trichloride and magnesium, are in the gaseous state at temperatures above 1107 ° C, and metallic aluminum and magnesium chloride are in the liquid state at the same temperature, which is convenient for constituting successively high and efficient production It is a situation.

As evidenced by the results of thermodynamic calculations, the process of Scheme (4) is characterized by an enthalpy value of -240 kJ and a Gibbs energy value of -210 kJ at a temperature of 1300 K (1027 ° C) do. This means that the process voluntarily works and emits a large amount of heat. However, a very high possible rate of recovery process should be taken into account with regard to the high reactivity of aluminum chloride and gaseous magnesium metal, which is in the vapor phase and is partially superheated to about 900 ° C. during partial dissociation into monochloride. In addition, the indexes &quot; g &quot; and &quot; l &quot; correspond to gas phase and liquid states following the second law of Le Chatelier and thermodynamics at higher pressure, Will have a balanced balance. For its dynamics, the reaction can take place by means of an explosion, which must be controlled by the velocity of the mother element, aluminum chloride and magnesium, and fed to the separate flow of inert gas with a lower temperature than that supported in the reactor.

The recovered process can occur at a temperature of 900 DEG C because the saturated vapor tension of magnesium in this state is considerable and forms, for example, about 0.19 at 927 DEG C. At the same time it is not reasonable to raise the temperature considerably above the boiling point of magnesium (1103 ° C to 1107 ° C), since this temperature increase is accompanied by a much higher velocity value of the process, so 1150 ° C can be set as the highest threshold have.

The total pressure of the gas phase in the reactor is assigned within 0.01 to 5.0 at the optimum partial pressure of the experimentally equivalent aluminum chloride and magnesium. It is preferred to be oriented at the upper value of the total pressure, but to avoid reaching its explosion limit.

For the composition of the gaseous mixture fed to recover, it should correspond to the stoichiometric ratio of mass contained in Scheme (4) and form 3.69: 1 for the aluminum trichloride and magnesium mass flow fed to the reactor.

The feasibility of the claimed invention is certain because there is a similar formation of titanium from tetrachloride in a magnesium-thermal manner. In addition, the claimed mode of accommodating aluminum becomes much simpler. Magnesium also has more negative metal than aluminum. The power input may be rather small when magnesium is received from the dolomite by its recovery in combination with the conventional method of magnesium chloride electrolysis. Moreover, the process is a self-production process.

Modes of using gaseous aluminum chloride and magnesium as parent materials for the acceptance of the resulting product of magnesium chloride and aluminum as liquids can be realized in a sealing device. It is automation-friendly and does not require the application of any mechanical device or any manual labor input to provide a process. The highly recognized ecological properties of the present invention for the application of a sealing device are apparent. The possibility for designing a device with high productivity per reactor, low construction and production input is one of the significant advantages of the mode provided.

The feasibility of the present invention is demonstrated by the presence of powerful and efficient industries of titanium extraction from tetrachloride using magnesium thermal methodology and also by the smooth realization of recovery of zirconium and hafnium from the chloride by progress of the magnesium thermal process.

With respect to the magnesium thermal system of the titanium reservoir, a cylindrical vessel of steel was initially used as the recovery apparatus. Steel cylinders are made of chrome-nickel steel, for example, lined with molybdenum plates. Subsequently, the lining is made of low-carbon steel. The process is realized at a temperature lower than the metal melting temperature, so that the titanium is accommodated in a solid-state state such as a sponge. To extract the sponge, the reactor will be cooled. Thus, the overall process is inevitably characterized as a cyclic process requiring manual labor input in its own sequence, reducing reactor efficiency, increasing energy input, and deteriorating the ecological characteristics of the manufacturing.

In the claimed invented apparatus intended for the metal heat recovery of aluminum by magnesium, the process takes place at a higher temperature reaching 1100 캜 to 1150 캜. In this state, the recovered product aluminum and magnesium chloride are in a liquid state and flow downward into the bottom portion of the reactor. The melting temperature of aluminum is 660 캜 while the melting temperature of magnesium chloride is 708 캜 to 714 캜 and correspondingly has a boiling point temperature of 2497 캜 and 1412 캜 to 1417 캜. To this end, the top of the reactor is made cylindrical to increase the useful volume of the reactor while the bottom part of the reactor is conical to collect liquid aluminum and magnesium chloride.

Most reaction zones are made hollow, where vaporous aluminum chloride and magnesium are introduced to more fully mix them and the volume adjacent to the conical part is filled with a hollow ceramic piece of a thin wall of a Las cig ring type attachment. The use of deposits accelerates the process of condensation and drops fusions that form aluminum and magnesium chloride.

The flow of the inert gas connects the reactor and the apparatus for separating the liquid magnesium from the caustic evaporation magnesium and the residue mixture of magnesium and aluminum chloride vapor. The cauldron, which is a magnesium evaporator, and the apparatus for separating liquid magnesium are all integral parts of the apparatus. Rather, they are located separately from the reactor.

The reaction of aluminum recovery from its chloride by magnesium in the gas phase is an exothermic reaction and accompanied by the release of large amounts of heat, and the process is a self-production process. To closely control the rate and temperature of recovery, the reactor and the magnesium separator are equipped with a system of boiling water cooling which evaporates.

Fluid conditions (liquid and gas) are used in the present invention under consideration. Fluid conditions are provided for high efficiency of the process by reacting in turbulent flow at high temperature.

In addition, the fiscal expenditure intended for the generation of the manufacturing facility is lowered along with the financial expenditure for the maintenance of the equipment.

Figure 1 is a general view of the reactor.
In FIG. 2, a cauldron-evaporator can be seen.
Figure 3 shows a device for separation.
Both of which are vertical cross-sectional views.

The reactor (FIG. 1) is manufactured as a cylinder 1 of the steel which converts the recovered products, namely aluminum and magnesium chloride, to the conical bottom part 2 intended for collection. A false bottom 3 is located between the cylinder and the conical portion. The reactor is sealed with a lid (4). All internal surfaces of the reactor are lined with refractory material 5 such as magnesite, graphite and other inert stuff.

An attachment 6 made of a thin wall ceramic of the Raschik ring type and typically applied to chemical absorption technology is placed on the pulse bottom 3. The attachment is made of an inflammable material such as magnesite, carbonitride, and the like.

The nozzles and injectors 7 and 8, which are in contact with the horizontal section circumference of the reaction zone and which are fixed in the upper hollow portion of the reactor facing towards each other, are used to introduce parent materials of vapor aluminum chloride and magnesium metal (gas) into the reactor do. The recovered aluminum 9 and magnesium chloride 10 are collected in the conical bottom portion 2 of the reactor so that the magnesium chloride 12 leaks through the tapped holes 11 and the aluminum 13 collects do. There is a branch pipe 15 installed in the lid of the reactor to remove the mixture of aluminum chloride and magnesium not contained in the reaction from the reactor.

The cauldron-evaporator (FIG. 2) is a hemispherical steel 16 sealed with a lid 17, all lined with the same material as the reactor. Magnesium is introduced into the cauldron in a liquid state. The electric heater 18 is immersed in the metal. Can be formed as a set of silicon carbide rods and are surrounded by a protective magnesite coating. The inert gas (argon or nitrogen) is fed into the cauldron-evaporator. In its vapor state, magnesium is guided into the reactor together with the inert gas. The cauldron-evaporator is equipped with a system of diverging water cooling, such as the other elements of the apparatus given in Figures 1 and 3.

The separator (FIG. 3) intended for the separation of aluminum chloride and liquid magnesium from the residual mixture is a smaller sized reactor lined with an anti-fouling ceramic 19. The branch pipe 20 feeds the gas mixture into the apparatus and the fluid magnesium condenses and collects in the bottom portion of the apparatus. Residual aluminum chloride not contained in the reaction is removed from the apparatus through another branch pipe 21 and the remaining aluminum chloride is recovered back into the reactor. A separation device such as a reactor is provided with a lock unit 22 and a divergent cooling system 23. The condensate of magnesium is returned back into the cauldron-evaporator and then further back into the reactor.

The apparatus continuously feeds the vaporized magnesium and aluminum chloride vapor to a reactor, either in a single cauldron evaporator or in a set of such evaporators. Aluminum chloride and gaseous magnesium are supplied to the reactor in the incoming turbulent flow of the inert gas, which is provided for ideal conditions to contact the reactive particles, remove diffusion barriers and enable a high speed recovery process . It is necessary to utilize a larger number and larger surface of active center of liquid state formation from the reactor to achieve greater withdrawal rates of the final products, i. E. Aluminum and magnesium chloride. This is achieved as a result of using the above-described thin walled and non-uniform deposits of the Ruschig ring type made of magnesite. The aluminum 13 released from the reactor in a continuous or periodic mode is protected by a good coating of the molten magnesium chloride 12. Separation of recovered products can be realized with ease. For example, a coating of magnesium chloride may transform the state of the magnesium chloride to a solid state while the drop in temperature falls to 680 ° C to 700 ° C, while the liquid aluminum may be easily directed to be included in other technical work.

Separators intended for the separation of aluminum chloride from magnesium in their residue gaseous mixture operate as a result of a pressure drop in the system and a drop in temperature below the magnesium boiling temperature. When the condensate is sufficiently cleaned, the liquid magnesium in the form of condensate is directed to a cauldron so as to be purified or evaporated and then further directed to the reactor.

A system of water divergent cooling is provided for both the reactor and the separator to provide a high but controllable recovery rate. The working principles of such equipment, which are used in many fields of technology, including metallurgy, are widely known and fine tuned. The system of inert gas circulation is also highly controllable both in chemical technology and in metal metallurgy.

The use of the technique of the present invention requires the vapor phase of aluminum chloride to be introduced through the injector 7 into the upper part of the cylinder of the steel 1 associated with the reactor (Fig. 1). The gaseous or vapor phase magnesium mixed with the inert gas introduces the same way back-flow through the injector 8. This mixture is prepared in a cauldron-evaporator (FIG. 2). The parent agonist, i. E., Inert gas (e. G., Argon), and liquid magnesium are introduced separately therein while the two-component flow of gaseous magnesium and inert gas is removed from the cauldron and sent to the reactor (FIG. 1) (Fig. 1).

The liquid aluminum and magnesium chloride formed condense and coalesce the deposit 6 (Fig. 1) into the conical part of the reactor, and further through the tap hole 11 the liquid aluminum and magnesium chloride are recovered, And magnesium chloride (12) in the pan (14). The residue gaseous mixture is extracted via branch pipe 15 (Figure 1). This mixture is introduced into the separation unit through the pipe 20 (Fig. 3), and then the magnesium removed from the separation unit through the lock unit 22 is returned back into the cauldron-evaporator, 1), the aluminum chloride is extracted through the pipe 21. In this case,

Industrial availability

The feasibility of the present invention submitted is without doubt, and a similar but very much more complex process of magnesium-heat recovery of titanium from its tetrachloride is available and is widely used in some countries of the USA, the Russian Federation and UIS Is confirmed.

The present invention presented is provided for many advantages regarding the technology of aluminum containment and new equipment. This is a low budgetary expenditure for manufacturing new manufacturing facilities and undefined high unit efficiency of the device. Sealing and the ecological safety of the manufacture. Hard manual labor is excluded from manufacturing and can be thought of as full automation of the process. The recovery of aluminum in the device occurs with a significant positive thermochemical and heating effect and is achieved without any self-production mode, without actually consuming any energy from the outside.

Claims (3)

A method of producing aluminum by metal heat recovery of aluminum from aluminum trichloride using inert gas and magnesium flowing,
Characterized in that the parent substance, which is aluminum trichloride, is introduced into the process as a vapor phase material and the resulting product, which is aluminum and magnesium chloride, is discharged as molten liquid material.
Aluminum production method.
The method according to claim 1,
The said number of times is between 900 ° C and 1150 ° C and 0.01 atm. To 5.00 atm, and the mass correlation of said aluminum chloride and said magnesium in a mixture of aluminum chloride and magnesium is 3.69: 1.00.
Aluminum production method.
An apparatus for carrying out a method as claimed in claim 1, comprising a cylindrical reactor with a thin walled attachment made of ceramic, said thin walled attachment being located inside a reactor having a conical bottom part,
The reactor comprises a cauldron-evaporator for evaporating magnesium into a flow of inert gas and a separator for separating magnesium chloride from the residual mixture, wherein the cauldron-evaporator is installed in front of the reactor, Characterized in that it is disposed after the reactor and all of the components of the apparatus are lined with an &lt; RTI ID = 0.0 &gt;
Device.

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