CN110819822B

CN110819822B - Electric heating aluminum smelting device

Info

Publication number: CN110819822B
Application number: CN201910875622.1A
Authority: CN
Inventors: 牛强; 储少军; 庞建明; 王耀武; 郭占成; 陈为亮; 夏明国
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-09-17
Filing date: 2019-09-17
Publication date: 2024-03-19
Anticipated expiration: 2039-09-17
Also published as: CN110819822A

Abstract

The invention belongs to the field of materialogy, and relates to an electric heating aluminum smelting device which comprises the following parts: at least one aluminum-magnesium centrifugal separator, wherein the aluminum-magnesium centrifugal separator receives alloy liquid containing four elements of aluminum, magnesium, silicon and iron which are melted by iron-containing aluminum alloy and magnesium metal, and the alloy liquid is separated into aluminum-magnesium alloy liquid and separated out solid-phase metal compounds after centrifugal treatment, and aluminum-magnesium alloy blocks are generated after the aluminum-magnesium alloy liquid is cooled; at least one aluminum-magnesium continuous distillation and separation furnace, which receives aluminum-magnesium alloy blocks produced by an aluminum-magnesium centrifugal separator, remelts and distills the aluminum-magnesium alloy blocks to separate the aluminum-magnesium alloy blocks into aluminum liquid and magnesium vapor, and the magnesium vapor is condensed to generate condensed magnesium. The invention adopts metal magnesium as extractant, separates aluminum, silicon and iron by physical method, realizes mutual melting of aluminum and magnesium, eliminates iron and silicon from alloy liquid, and then distills and separates aluminum and magnesium.

Description

Electric heating aluminum smelting device

Technical Field

The invention belongs to the field of materialy, relates to a device for purifying aluminum, and in particular relates to a device for electrically heating aluminum.

Background

Aluminum is an important metal, and is widely used, being the second metal next to steel. At present, the metal aluminum in the world is produced by adopting an electrolytic aluminum process. However, the electrolytic aluminum process has a number of important disadvantages that are difficult to overcome. This has led to a constant search for an electrothermal aluminum process to replace electrolytic aluminum. Electrorefining aluminum has advantages over electrolytic aluminum in several respects, at least potential advantages that can be expected: (1) first of all differences in mineral origin: the aluminium-containing minerals are approximately 250 more than 100, i.e. 40% of the aluminium-containing minerals are silicates, i.e. in most cases the aluminium-containing minerals are aluminosilicate. The electrothermal method can use the aluminosilicate ore, and is very wide in nature. The electrolytic aluminum needs aluminum-containing minerals with extremely high purity, namely bauxite with extremely high aluminum-silicon ratio, such as minerals with aluminum-silicon ratio of 5-12, the suitable minerals are extremely limited, and the common gibbsite, diaspore, boehmite and the like are limited, so that the electrolytic aluminum is suitable for the spatial maldistribution of mineral resources of the electrolytic aluminum. The annual raw aluminum production is about 6000-7000 ten thousand tons worldwide, of which about 51-55%, i.e. about 3600 ten thousand tons, are produced in China, and the bauxite resources in China account for only 2.7% of the world. If China does not import bauxite or alumina, the quality bauxite suitable for electrolytic aluminum in the country will be depleted within 7 years. The global bauxite ore-forming zone is mainly distributed in africa, oceangoing, south america and southeast asia. From a national distribution, bauxite is mainly distributed in the countries of guinea, australia, brazil, jamaica, vietnam, indonesia, etc. Almost all of the world's primary aluminum producing countries in China, north America, europe, etc. require imported bauxite. That is, most of the major industrial countries in the world, located in the eastern asia, western europe, eastern european region of the soviet union, north america, etc., are devoid of bauxite suitable for electrolysis of aluminum. (2) the pollution emission in the production process is as follows: the pollution in the whole process of electrolytic aluminum production is serious. The electrolytic aluminum production process is firstly to produce alumina and secondly to electrolyze. The two links produce a large amount of red mud, fluoride smoke dust, fluoride gas, cyanide and other various pollutants caused by cathode overhaul slag, and some of the two links are extremely toxic pollutants, so that serious harm is caused to ecological environment and human health. The electrothermal method is used for producing aluminum, almost no pollution which is difficult to control is caused, oxide dust in the submerged arc furnace has no chemical toxicity, and the method is easy to control. The whole production process has no treatment cycle of acid-base waste liquid, and the whole environmental protection level is much better. (3) third is a difference in energy consumption level: the current whole process of aluminum electrolysis has the process electricity consumption of about 13000kwh per ton of aluminum, but about 1.92 tons of aluminum oxide is needed per ton of aluminum, and the aluminum oxide preparation process is equivalent to the energy consumption of about 20-60GJ per ton of aluminum. If an electrothermal method is adopted, the energy consumption of each ton of alloy is mainly the process electricity consumption, and under the condition of comprehensive recovery, only 12000kwh is needed, and not too much energy consumption in the raw material preparation process is needed, or the energy consumption of the raw material preparation ring is far lower than that of the alumina link. (4) large difference in capacity of the equipment: the electric heating aluminum smelting device is compact, the power and the productivity of a single device are much larger, the voltage reaches hundreds of volts, and the voltage of the electrolytic tank is only one digit. The aluminum production per year of each large-scale electrolytic tank is hundreds of tons, and the electric heating method of the large-scale submerged arc furnace can be used for smelting aluminum to ten thousand tons. This is because, on the one hand, the electrolytic reaction is carried out only on a planar surface, whereas the electrothermal process is carried out in the entire three-dimensional space. Also the overall energy efficiency of the electrolysis process is not high, whereas the electrothermal principle is much higher. From the perspective of the reactor, the electrolytic aluminum workshop often has hundreds of electrolytic tanks connected in series to operate, and the requirements on electric power stability, operation management and maintenance are much higher. The reactor of the electrothermal method has large capacity, less equipment and more flexible production management. (5) adaptability to use of renewable energy sources: electrolytic aluminum can only use electricity produced from conventional fossil energy sources. In the electrolytic aluminum production process, the electrochemical reaction of the electrolytic tank is required to be continuously carried out, once power failure occurs, major production accidents of the coagulation tank are caused, production is stopped, and the recovery is required to be thoroughly re-overhauled, so that the cost is high, and the construction period is delayed for a plurality of months. The electrolytic aluminum is used as a large electricity consumption user, but renewable energy sources such as wind power, photovoltaic, photo-thermal, hydropower and the like cannot be used to prevent power supply fluctuation, and only power generated by fossil energy sources such as traditional coal, gas, fuel oil and the like can be used, so that the effort of global carbon emission reduction cannot be implemented in the electrolytic aluminum industry. (6) treatment of silicon element: in the two-step process of electrolytic aluminum smelting, firstly, the oxide of aluminum and silicon is forced to be separated under the action of aqueous solution, then a large amount of heat energy is consumed to dry the water in the aluminum oxide, and the aluminum oxide is fed into an electrolytic tank to obtain the electrolytic aluminum. However, in the final application of electrolytic aluminum, about 70% of the aluminum is required to be subsequently blended with industrial silicon as an alloy element, which results in great waste. In particular, as high grade bauxite is gradually consumed, more aluminum-silicon is lower than that of bauxite with 3-6 aluminum-silicon ratio, for example, more silicon oxide needs to be removed, which results in complex process and increased cost. The electrothermal method directly reduces aluminum and silicon into alloy in a synergistic way, so that the aluminum and the silicon do not need to consume great force to separate the aluminum and the silicon in an oxide state, moisture is not required to be dried, and industrial silicon is not required to be specially matched in the later stage to improve the silicon content. Obviously, the electrothermal method is more reasonable in the utilization of the accompanying silicon element. And (7) the electrothermal method has huge cost advantages: the production cost of electrolytic aluminum is high. In the production cost of the electrolytic aluminum, the electric power energy accounts for about 40 percent, and the purchasing cost of the aluminum oxide is important, wherein the aluminum oxide consumption per ton of the electrolytic aluminum is generally 1.92 tons, and the aluminum oxide purchasing cost accounts for 40 percent of the selling price of the electrolytic aluminum, so that the cost of the electrolytic aluminum is high. Under the same conditions, the cost of the electrothermal method is reduced by about 30% compared with that of ton aluminium by electrolytic method.

Along with the continuous increase of the global aluminum consumption, the accumulation of metal aluminum and aluminum alloy in society is also increasing, which means that the recovered waste aluminum accumulated in the industrialization process becomes the main source of future metal aluminum, that is, the regenerated aluminum replaces the original aluminum and becomes the main aluminum source. However, the recycled scrap aluminum often contains excessive iron, for example, the iron content is more than 1.5% or even higher, the quality of the recycled aluminum is affected, the iron content is often reduced to a qualified level by adding a plurality of times of pure electrolytic aluminum for dilution, which means that the low cost and low energy consumption of the recycled aluminum are diluted by the electrolytic aluminum, as the recycled aluminum becomes the main stream in the future, and much electrolytic aluminum is not used for dilution in society, so that the accumulation of iron gradually rises along with the cycle number, and the aluminum alloy is degraded. At present, no good effect is received by adding manganese to remove iron, assisting in filtering by an electromagnetic field and the like. Therefore, development of a process technology for removing iron after melting recovered scrap aluminum is urgent.

The quality bauxite suitable for electrolytic aluminum stored in China is not abundant. But there are relatively many low-quality aluminum-containing solid wastes, such as high-alumina fly ash, high-alumina gangue, bauxite tailings, etc. For example, in the middle and western regions of inner mongolia and the middle and north regions of shanxi province of china, the aluminum content in coal is high, the aluminum-silicon content in the fly ash after coal combustion is high, possibly even more than 1, and the aluminum content in the rest of coal gangue is high. In the partial bauxite production area with little north in China, low-quality bauxite tailings, such as the ratio of aluminum to silicon is between 1.5 and 3, are always abandoned due to being lower than the purchasing standard of downstream alumina enterprises, and have large accumulation amount, and the total conservation amount of the low-order bauxite resources is more, so that a good utilization method is not provided at present.

The large Tang electric power group is combined with the Qinghua university, a research institution of high alumina coal is built in an industrial garden of the Erdos university of inner Mongolia, and an industrial production line for extracting alumina by leaching high alumina coal ash is built, but if the low-order resource is used for removing silicon oxide and the like, the pollution emission and the energy consumption level are higher than those of the existing electrolytic aluminum overall process, and the low-order resource has no value in both economic and environmental protection aspects. These production lines and their technical routes have not been popularized and eventually removed by themselves.

The world has focused attention on directly smelting metallic aluminum from bauxite using electrothermal processes with carbon as a reductant, which has been an effort for over a century. Through extensive research and accumulation, several facts and conclusions can be confirmed: (1) direct reduction of aluminum by carbon is difficult. On the one hand very high temperatures, about 2000-2200 c, are required and on the other hand the resulting aluminium is directly bonded to carbon to aluminium carbide instead of metallic aluminium. Due to the elevated temperature, a significant amount of aluminum volatilizes into the furnace atmosphere rather than remaining in the furnace. If vacuum melting is used, there is more of a situation where a large amount of aluminum volatilizes. (2) The method is easier to achieve the synergistic reduction of aluminum silicon oxide than pure aluminum, aluminum silicon alloy is obtained, and if the preferential reduction of iron oxide exists, the generated aluminum and silicon metals are directly mutually dissolved with iron, so that the method is more beneficial. Generally, such aluminum-silicon alloys are theoretically reducible as long as the aluminum content does not exceed 72%. It is further advantageous if the aluminium silicon contains some iron, for example 5-10%. (3) In many domestic ferroalloy enterprises, the aluminum-containing alloy, such as aluminum-silicon alloy or aluminum-silicon-iron alloy, is tried to be reduced by an ore-smelting furnace, and the aluminum content below 35% is generally easy to realize. If the alumina content of the charge stock is high, exceeding 40%, even if it is blended in the alloy at 50-60%, refractory carbides such as silicon carbide are particularly easily produced, resulting in rising of the furnace bottom, so that the production is forced to stop. (4) In the industrial silicon production process, the problem that the furnace bottom is raised due to the generation of silicon carbide is also solved, and the furnace bottom is well controlled by means of process control, furnace bottom rotation and the like. (5) The smelting of high aluminum-containing aluminum-silicon or aluminum-silicon-iron alloy belongs to a difficult-smelting variety, and requires grinding, pelletizing and drying of raw materials, careful process control and production operation, and the furnace type generally suggests a relatively large power density, a relatively large furnace bottom density, relatively concentrated heat supply, relatively rapid heating rate of furnace burden and parameter optimization in the aspect of polar circle and hearth height-diameter ratio.

In general, the world-wide view can realize stable commercial production for decades, and some electrothermal aluminum-silicon alloy production lines with the soviet union period, such as Nie Ba factories, have 8 ore-smelting furnaces with more than 16500KVA for related production, the aluminum content of the product is about 50-60 percent, and the electricity consumption is at the level of 12000-14000 kwh/ton of alloy.

In the 21 st century, the aluminum industry company of the dengue electric group of China is introduced into the Ukraut expert team grasping the Soviet Union technology to conduct technical guidance, after years of fumbling, stable commercial production is realized on the same 16500KVA alternating-current submerged arc furnace, the aluminum content of the product is about 50-60%, the silicon content is more than 30%, the iron content is less than 10%, and the product is identified by Henan province and is listed as an international talent cooperation demonstration project by the national foreign expert agency.

However, the aluminum silicon iron with high aluminum content can not be used as the aluminum alloy of the metal structural material no matter the aluminum industry for realizing stable production in the soviet union, the ukraine and the Chinese only one. It is generally required to reduce the iron content to below 1% and the silicon content to below 13%, so that the alloy can be used as a casting alloy of structural materials in aluminum alloys, otherwise, the alloy can only be used as a composite deoxidizer in ferrous metallurgy processes, and the alloy is far cheaper than aluminum for chemical functions. Tests of iron and silicon removal of the high-aluminum alloy have been carried out, such as manganese addition, filtration and iron removal, and dilution of the high-aluminum alloy to about 10% silicon content by multiple times of electrolytic aluminum, which results in that the electroheat smelting aluminum-silicon alloy cannot be separated from the electrolytic aluminum and exists independently, and the advantage of low raw material cost is also eroded by multiple times of high cost of the electrolytic aluminum.

Therefore, even though the technology and equipment technology for electroheat smelting of aluminum-silicon alloy are carefully mastered, aluminum-silicon-iron alloy with high aluminum content of about 60% can be produced, but aluminum, silicon and iron in the alloy cannot be thoroughly separated to obtain structural metal aluminum, so that the technology has no strong commercial competitiveness and cannot replace the existing electrolytic aluminum technology.

U.S. Pat. nos. 2829961, 2974032, 4099959 and 4213599 disclose that thermal reduction of alumina directly with carbon is difficult to obtain metallic aluminum and that staged reduction of aluminum can be achieved by forming aluminum carbide as an intermediate reducing agent.

US patent 7704443 describes the heating of a molten mass with a side wall electrode plus a top electrode to obtain aluminum vapor. US7819937 proposes the recovery of an aluminium-containing product in the gas phase by means of a feed device.

Richard J Fruehan in US6849101 is proposed to absorb carbon-heat aluminium intermediate carbides in furnace gas with porous charcoal to obtain metallic aluminium by reaction with aluminium in gas phase and aluminium oxide.

The patent number 200980150004.5 filed by the American aluminum company into China proposes to separate aluminum carbide from metallic aluminum by cooling to separate out precipitate.

The Chinese patent 200610051148.3 of the Chinese aluminum industry application proposes that the submerged arc furnace directly produces aluminum-silicon-iron alloy, wherein the aluminum content is 38 percent, the iron content is 23 percent, and the aluminum-silicon-iron alloy is feasible as a deoxidizer, but the difference between the aluminum content and the iron content is too small, so that the aluminum similar to the aluminum used for the structural material cannot be separated.

Chinese patent application 201710874459.8 proposes the use of manganese addition to remove and recover iron from recycled aluminum magnesium silicon alloys, and then removing iron-containing precipitates through ceramic foam filter screens to purify the aluminum alloy liquid.

Chinese patent application No. 98113973.6 and 201210242147.2 propose a device for purifying magnesium by distillation, but all are batch-type production, and the product is single high purity metallic magnesium.

Disclosure of Invention

According to the defects of the prior art, the invention provides an electric heating aluminum smelting device, which adopts metal magnesium as an extracting agent, separates aluminum, silicon and iron by adopting a physical method, selectively dissolves aluminum into the metal magnesium by utilizing the characteristic that molten magnesium liquid is infinitely and mutually soluble in a metal aluminum liquid, and realizes mutual melting of aluminum and magnesium by utilizing the characteristic that iron and silicon are hardly dissolved in the molten metal magnesium liquid, removes the iron and the silicon from an alloy liquid, and then carries out distillation separation on aluminum and magnesium.

The invention relates to a device for electrically heating aluminum smelting, which is characterized by comprising the following parts:

at least one aluminum-magnesium centrifugal separator, wherein the aluminum-magnesium centrifugal separator receives alloy liquid containing four elements of aluminum, magnesium, silicon and iron which are melted by iron-containing aluminum alloy and magnesium metal, and the alloy liquid is separated into aluminum-magnesium alloy liquid and separated out solid-phase metal compounds after centrifugal treatment, and aluminum-magnesium alloy blocks are generated after the aluminum-magnesium alloy liquid is cooled;

at least one aluminum-magnesium continuous distillation and separation furnace, wherein the aluminum-magnesium continuous distillation and separation furnace receives aluminum-magnesium alloy blocks produced by an aluminum-magnesium centrifugal separator, and the aluminum-magnesium alloy blocks are remelted and distilled and separated into aluminum liquid and magnesium vapor, and the magnesium vapor is condensed to generate condensed magnesium.

In the invention, the iron-containing aluminum alloy is an electrothermal aluminum-silicon alloy and an aluminum-silicon-iron alloy which are produced by reducing and smelting in a submerged arc furnace, wherein the iron-containing aluminum alloy contains 1-20% of iron, 40-72% of aluminum and 5-50% of silicon, and the raw materials used by the electrothermal aluminum-silicon alloy and the aluminum-silicon-iron alloy are natural minerals containing aluminum, silicon and iron and energy industrial wastes, and the raw materials comprise low-order bauxite, bauxite tailings, aluminum-containing fly ash, coal gangue, kaolin and the like; the iron-containing aluminum alloy can also be recycled scrap aluminum with iron content of 1.5-10%.

Wherein, the preferable scheme is as follows:

The aluminum-magnesium centrifugal separator is provided with a space surrounded by a centrifugal machine fixing cylinder wall and a centrifugal machine fixing cylinder protective cover plate, a detachable centrifugal cylinder is arranged in the space, the centrifugal cylinder comprises a centrifugal cylinder bottom plate, a centrifugal cylinder outer cylinder wall, a centrifugal cylinder inner cylinder wall and a centrifugal cylinder top plate, the centrifugal cylinder outer cylinder wall and the centrifugal cylinder inner cylinder wall are arranged between the centrifugal cylinder bottom plate and the centrifugal cylinder top plate with the same circle center, a centrifugal cylinder annular liquid receiving groove which is annularly arranged is arranged between the centrifugal cylinder outer cylinder wall and the centrifugal cylinder inner cylinder wall, an inner space surrounded by the centrifugal cylinder inner cylinder wall is a centrifugal cylinder inner cavity, a centrifugal cylinder liquid injection channel leading to the centrifugal cylinder inner cavity is arranged between the centrifugal machine fixing cylinder protective cover plate and the centrifugal cylinder top plate, and a plurality of liquid throwing holes are uniformly formed in the centrifugal cylinder inner cylinder wall. The centrifugal rotary drum of the aluminum-magnesium centrifugal separator is made of carbon steel, heat-resistant steel and the like, and the inner drum wall of the centrifugal rotary drum can bear aluminum-magnesium alloy liquid in direct contact with 500-1000 ℃. The centrifugal speed of the aluminum-magnesium centrifugal separator is 30-5000 revolutions, and the generated centrifugal acceleration is 10-1000 times of the gravity acceleration.

The aluminum-magnesium continuous distillation separation furnace comprises an aluminum-magnesium alloy remelting furnace, a magnesium distillation tower, an aluminum liquid heat preservation furnace, a magnesium condenser, a crystallized magnesium storage chamber, a total vacuum pipeline and a vacuum pump; the aluminum-magnesium alloy remelting furnace is communicated with a top feed inlet of a magnesium distillation tower through a vacuum liquid suction pipe, a bottom discharge outlet of the magnesium distillation tower is communicated to an aluminum liquid heat preservation furnace through an aluminum liquid concurrent pipe, the top of the magnesium distillation tower is also communicated with a top feed inlet of a magnesium condenser through a magnesium steam pipe, a bottom discharge outlet of the magnesium condenser is communicated with a crystallized magnesium storage chamber, and the top of the magnesium condenser is also communicated with a total vacuum pipeline and a vacuum pump.

In the invention, the resistance and induction heating or the non-contact indirect heating of fuel gas and hot air are adopted for the aluminum magnesium alloy remelting furnace and the magnesium distillation tower, the heating temperature of the aluminum magnesium remelting furnace is 500-900 ℃, the heating temperature of the magnesium distillation tower is 700-1200 ℃, and the vacuum degree of the magnesium distillation tower is 0.1-1000Pa. The inside of the magnesium distillation tower and the aluminum liquid concurrent pipe can hold an aluminum liquid column with the height of 3.5-5 meters, so that the aluminum liquid column in the magnesium distillation tower is sealed under the vacuum of local atmospheric pressure. And the device for blowing argon into the bottom of the magnesium distillation tower and the aluminum liquid down-flow pipe can be arranged to realize submerged argon blowing stirring or jet stirring of the aluminum liquid column.

A plurality of layers of distillation trays are vertically arranged in the inner cavity space of the magnesium distillation tower, an aluminum-magnesium liquid connection area is arranged on one side of the top of the distillation tray, an aluminum-magnesium liquid falling hole is formed in the other side of the top of the distillation tray, a surrounding baffle is arranged around the outer side edge of the top of the distillation tray, and a roundabout aluminum-magnesium liquid runner formed by a runner cofferdam is arranged between the aluminum-magnesium liquid connection area and the aluminum-magnesium liquid falling hole.

The shell of the magnesium distillation tower adopts a double-layer steel structure and comprises an outer shell and an inner shell, an interlayer between the outer shell and the inner shell is subjected to vacuum treatment, and a fireproof heat insulation layer is built on the inner wall of the inner shell. The interlayer is a pressure buffer area for vacuumizing, and the shell is a pressure-bearing steel shell for bearing the pressure difference between the atmospheric pressure and the interlayer.

The magnesium condenser is characterized in that a cooling cavity is formed in the magnesium condenser, the top of the cooling cavity is respectively communicated with a magnesium steam pipe, a total vacuum pipeline and a vacuum pump, the bottom of the cooling cavity is communicated with a crystallized magnesium storage chamber, a cooling device is wrapped outside the cooling cavity, a spiral magnesium scraper is arranged in the cooling cavity, a magnesium steam baffle is further arranged at the top of the cooling cavity, and the magnesium steam baffle is positioned between the cooling cavity and two connectors of the magnesium steam pipe, the total vacuum pipeline and the vacuum pump.

The cooling device comprises a negative pressure spray vaporization chamber, a vaporization negative pressure suction pipe and a vacuum pump, wherein the vaporization negative pressure suction pipe and the vacuum pump are connected with the negative pressure spray vaporization chamber, and a plurality of atomized water spray heads are arranged in the negative pressure spray vaporization chamber.

An upper crystallized magnesium locking valve is arranged between the magnesium condenser and the crystallized magnesium storage chamber, and a lower crystallized magnesium locking valve is arranged at the discharge opening of the crystallized magnesium storage chamber.

The crystalline magnesium storage chamber is respectively communicated with a vacuum air suction pipeline and a vacuum breaking inflation pipeline.

The height of the aluminum liquid down-flow pipe is calculated by multiplying the local atmospheric pressure divided by the standard atmospheric pressure by 4.5 m.

The specific process of the invention is shown in figure 1, and adopts an electrothermal reduction process completely different from the existing mainstream high-quality bauxite-alumina-electrolytic aluminum, low-grade bauxite, bauxite tailings, fly ash, coal gangue and other commonly existing aluminum-silicon resources or aluminum-containing solid waste as cheap raw materials, and adopts a thermal reduction method to smelt high-aluminum-silicon-iron alloy in a sealed submerged arc electric furnace, then further adopts molten liquid magnesium metal as a solvent and an extractant to selectively dissolve aluminum from the aluminum-silicon-iron alloy, effectively separates iron and silicon from aluminum-magnesium alloy liquid, adopts a condensation method or a fusion method and a condensation and fusion method, and adopts a hypergravity centrifugal separation method with much higher efficiency than natural gravity separation so as to enable more aluminum elements to enter the final aluminum alloy. Meanwhile, the byproduct ferrosilicon slag is used as a reducing agent for thermal reduction of magnesium metal, so that better comprehensive utilization is obtained. In the process, no aqueous solution participates in the aluminum extraction metallurgical chemical process and no fluoride aluminum smelting process is adopted, so that the aluminum smelting process has no aqueous solution, fluoride treatment and possible pollution risks;

Replacing a planar reactor of an electrolytic tank with a submerged arc furnace three-dimensional reactor to enlarge the capacity of a reduction reactor of single aluminum extraction metallurgy; the aluminum metallurgy reaction process of renewable energy power supply such as wind power, photovoltaic, photo-thermal and the like can be used, namely an aluminum smelting reactor and a production process thereof which are not influenced by power failure or power fluctuation, and the aluminum metallurgy reaction reactor can be used for generating power in a seasonal manner, or the aluminum metallurgy reaction process is similar to an aluminum metallurgy production line which can adjust power load in the middle east region in the power consumption peak period in summer, and has stronger adaptability to power fluctuation than an electrolytic tank.

The device and the method for realizing effective separation of aluminum and magnesium by distillation are developed, and the device and the production process are particularly suitable for large-scale industrialization and continuous production, and comprise automatic continuous feeding, stable continuous evaporation-escape-condensation of magnesium, continuous outflow of residual aluminum liquid, downstream alloying and ingot casting, and continuous discharge of condensed magnesium metal in a vacuum-free manner for the following remelting, alloying and ingot casting.

Along with gradual accumulation of the stock of the waste aluminum in society, the proportion of the regenerated aluminum is higher, but the waste aluminum with higher iron content is difficult to remove iron, so that great limitation is generated on the use of the waste aluminum, the iron is removed by adding magnesium, and then the aluminum and the magnesium are separated from each other by continuous distillation, so that a wide prospect is developed for the use of the waste aluminum with high iron content, degradation use is not needed, and more fresh electrolytic aluminum is not needed to be used for diluting and reducing iron; magnesium element contained in the waste aluminum is better recycled. The waste magnesium often contains a certain amount of aluminum element, and the aluminum recovery is better through the evaporation separation after the mutual melting of the aluminum and the magnesium. In the past, after the waste magnesium is directly distilled, a certain amount of aluminum and other metal elements are contained in the residue, and the residue is adhered to the inner wall of the distiller, has no fluidity and is difficult to remove. The refining of magnesium does not adopt a chemical refining method of fluorine-chlorine salt to pollute the environment, but adopts physical distillation, has good environmental effect,

In the conventional silicon thermal reduction process of magnesium, due to the fact that chemical refining is adopted, metal impurities such as Al, si, fe and the like are difficult to remove, so that a high-temperature and high-vacuum intensified extraction means cannot be used, and the equipment production capacity, the magnesium element recovery rate and the silicon iron utilization rate are always low. The method is adopted to directly mix the crystallized crude magnesium with the aluminum alloy for collaborative purification, so that the high-temperature and high-vacuum strengthening means and process can be adopted for a large amount, the yield, the magnesium element yield and the silicon element utilization rate are obviously improved, and whether impurities can be removed through refining in the follow-up process is not necessary, and silicon and iron elements enter filter residues and aluminum elements enter aluminum liquid for removal because of follow-up condensation and centrifugal separation;

the distillation of magnesium is a high-energy consumption process, and distillation volatilization of one ton of magnesium in industry is realized, so that even in a continuous production process, 15-20GJ energy is often needed, the indirect heating of fuel gas is adopted, the cost is saved compared with the electric power, the thermal power is converted by the fuel gas in many times, and the energy conversion efficiency is often only 30-42%; the distilled magnesium vapor is used as a heat source to indirectly heat new aluminum magnesium alloy liquid or magnesium liquid to volatilize and purify the magnesium, which is equivalent to using one time of metal magnesium distillation energy consumption to generate multiple times of magnesium distillation effect, and the energy-saving effect is more obvious.

The specific process principle of the invention can be described with reference to the following:

the desirable electrothermal aluminum smelting reaction is to contact and even deeply mix minerals containing aluminum oxide with carbonaceous reducing agent and pelletize, then send the minerals into electrothermal metallurgical equipment such as an ore-smelting furnace, and heat the minerals at high temperature by adopting an arc, and hopefully to react with carbon to reduce aluminum oxide, thus obtaining metal aluminum.

The following reactions, which are desirable, do not actually occur.

Al ₂ O ₃ +3C＝2Al+3CO

This reaction requires extremely high temperatures, up to 2000-2100 degrees celsius, according to the theory of chemical thermodynamics, to initiate the reduction.

ΔG ⁰ ＝325660+3.75TlgT-1.5507T

The calculated initial reduction temperature was in the vicinity of 2295K absolute, i.e. 2022℃according to the above formula. The free energy of reaction values calculated by the widely accepted international commercial software for chemical thermodynamics, pictsage 7.3, are shown in the following table, starting to produce metallic aluminum at about 2053 ℃.

TABLE 1 Standard free energy of alumina reduction by carbon

Temperature (degree centigrade)	Delta G ⁰ (J)
		1400.00	364910.5
1500.00	307004.8
		1600.00	249307.9
1700.00	191812.4
		1800.00	134511.4
1900.00	77398.9
		2000.00	20468.9
2053.87	-10122.7
		2100.00	-33911.1
2200.00	-85180.4

But even at such high temperatures, the reduction does not result in metallic aluminum, but mainly aluminum carbide. That is, the reaction actually follows occurs in large amounts.

2Al ₂ O ₃ +9C＝Al ₄ C ₃ +6CO

At high temperatures, aluminum carbide and aluminum oxide dissolve in a large amount with each other and the resulting metallic aluminum is dissolved, making it difficult to obtain metallic pure aluminum from the product. At the same time, at the high temperature above 2000 ℃, the CO gas of the furnace gas is escaped in the form of aluminum vapor along with the massive volatilization of aluminum.

The carbothermic reaction is much more advantageous if the mineral used is a complex oxide of aluminum silicon or if silicon oxide is co-reduced with aluminum oxide.

The chemical reaction represented by the following formula is one of the main reactions for producing ferrosilicon, industrial silicon, and other silicon-based alloys.

SiO ₂ +2C＝Si+2CO

In fact, the reduction process of silicon also involves the reaction of carbides as intermediate products. The following steps are provided

SiO ₂ +3C＝SiC+2CO

However, the presence of carbide further reacts as follows to reduce the semi-metallic silicon.

2SiC+SiO ₂ ＝3Si+2CO

The intermediate product of the aluminum reduction process, aluminum carbide, is also capable of reducing silicon oxide, such that the aluminum silicon is co-reduced as shown in the following equation. The molar ratio of the produced aluminum to the silicon is 8:3, and the mass fraction of the aluminum is 72 percent, which is also the reason why the aluminum content cannot exceed 72 percent theoretically when the industry generally considers that the aluminum-silicon alloy is prepared by electrothermal reduction.

2Al ₄ C ₃ +3SiO ₂ ＝8Al+3Si+6CO

In addition to the intermediate products silicon carbide, aluminum carbide, the action of alumina with carbon may also produce carbon oxides.

4Al ₂ O ₃ +Al ₄ C ₃ ＝3Al ₄ O ₄ C

In the whole process of reducing aluminum silicon oxide by carbon, gaseous products such as intermediate valence silicon oxide, aluminum oxide and the like are also generated. As shown in the following reaction scheme

SiO ₂ +C＝SiO↑+CO↑

Al ₂ O ₃ +2C＝Al ₂ O↑+2CO↑

During the rising process of the low-valence gas oxides, if the hearth is deeper, the reaction can be continued, so that the aluminum-silicon alloy is obtained. This requires a relatively deep reactor design so that the gaseous intermediates have sufficient residence and reaction time.

Because of the presence of silicon, aluminum carbide is destroyed, and in particular silicon is a homogeneous element with carbon, and silicon has greater activity to combine with other elements such as aluminum and occupies the original carbon position, so that aluminum-silicon alloy is produced in large quantity instead of aluminum carbide. After the silicon and the aluminum are mutually dissolved, the activity of the aluminum is reduced, and the reaction of reducing to prepare the aluminum is performed to a larger extent.

In general, theoretical and practical conclusions about electric furnace smelting of aluminum-silicon alloys indicate the following suggestions: (1) The ore-smelting furnace is used for smelting aluminum-silicon alloy or aluminum-silicon-iron alloy, which is industrially feasible, and pure aluminum cannot be obtained by an electrothermal method; (2) Adopting the low-cost resource containing aluminum and silicon in the nature or energy industry, if the alloy containing 50-60% of aluminum can be smelted on the premise of the aluminum-silicon ratio of 1.3-1.6, if the alloy is allowed to contain 5-10% of iron, the smelting difficulty is easier than that of the aluminum-silicon alloy containing less than 1.5% of iron; (3) Before the ore is put into the furnace, the ore is required to be ground together with a carbonaceous reducing agent, the ore is pelletized by using a binder and then is subjected to certain pressure, and the pellets which are dried to be of certain strength are put into the furnace, so that certain strength can be maintained in the furnace, and the CO gas which is a reduction product can escape from a hearth through a gap. The pellet compression strength is too low, and the pellets are easily crushed in the furnace, so that the gas channel is blocked. The ball pressing strength is too high, the ball is too compact, and the reducing process gas cannot escape from the ball, so that further reduction is prevented. (4) Many reducing agents can be selected, such as bituminous coal, and the reducing agents have certain volatile components, and the pellets become a porous structure after being heated, so that the escape of reaction gas is facilitated. Other carbonaceous reducing agents such as biomass carbon, petroleum coke, semi-coke, anthracite are also suggested, but in general, porous carbonaceous reducing agents are desirable; (5) The amount of the carbonaceous reducing agent is slightly lower than the theoretical metering, for example 94% is better, so that the generation probability of carbide can be reduced; (6) High-alumina fly ash, coal gangue, low-order bauxite, tailings thereof, kaolin and the like are all suitable low-cost aluminum-silicon mineral resources. In Shanxi jin, north is a quaighur, such as the plastic state and the inner Mongolia, the quaighur has a large amount of high-alumina coal resources, the alumina-silica ratio can reach 1 or more than 1, and the coal gangue and the fly ash of the coal-fired power plant are also high-alumina. In addition, in bauxite production areas such as Shanxi, henan and Guangxi of China, a large amount of low-order bauxite or bauxite tailings with the aluminum-silicon ratio lower than 3 are abandoned in a large amount because of being not in accordance with the purchasing standard of an alumina plant used for electrolytic aluminum, and are also good mineral resources of electrothermal aluminum-silicon alloy through blending; (7) If the raw material contains a high level of calcium oxide, this is not a favorable burden. The melting point of the furnace burden is reduced due to the calcium oxide, so that the furnace burden is molten prematurely, and the reduction process of aluminum silicon is affected. When part of high-sulfur coal is combusted in a boiler combustion chamber, in order to reduce the burden of subsequent flue gas desulfurization, a certain amount of lime is often mixed to participate in combustion, so that the lime content in the fly ash of a power plant is higher than that of the original coal, which is a disadvantageous factor; (8) From the viewpoint of subsequent extraction of metallic aluminum, the higher the aluminum content is, the better the lower the iron content is, but from the difficulty of submerged arc furnace smelting, generally, the better level can be achieved is 55-63% aluminum, 30-36% silicon, 2-10% iron, and a small amount of titanium, which is generally considered to be incorporated into iron; (9) The operation of the submerged arc furnace is affected, and besides the smooth outflow of the alloy liquid, the risk of rising of the furnace bottom is also caused. The alloy liquid is not easy to flow out, namely the alloy with high aluminum and low iron has very small density which is in the order of 2500kg/M3 and even lower than the density of ores and carbides, which is different from other common iron alloys, so that the alloy liquid floats above furnace charge in a hearth, the tapping is difficult, the current does not pass through the hearth to cool the hearth, refractory carbides such as silicon carbide are generated to be deposited and rise on the hearth, the production is finally carried out for a very short time, the furnace has to be stopped for overhaul, even hard hearth carbides which are difficult to clean need to be fried, and the production process can be maintained for only tens of days; (10) The produced aluminium-silicon alloy and aluminium-silicon-iron alloy contain certain carbide, unreacted alumina-silica, etc. and are mixed in alloy liquid, and need to be refined and removed. The refining method is preferably chemical refining, a small amount of halide is used as a refining agent for removal, and physical methods such as a hypergravity centrifugation method can be considered, so that the environmental pollution in the use process of the halide is reduced; (11) Attempts have been made to reduce the initial temperature of the reduction reaction by carbothermic reduction of alumina under vacuum conditions, but the effect is not ideal, because the vacuum reduces the temperature at which the reduction reaction begins, but also reduces the boiling point of the metallic aluminum, resulting in a large amount of volatilization of the metallic aluminum generated under vacuum; (12) From the electric furnace equipment perspective, the alloy is suitable for electroheat smelting of aluminum-silicon alloy, and is similar to refractory high-silicon alloy such as industrial silicon, for example, calcium-silicon alloy and the like. The rotary furnace shell adopted by the industrial silicon is better to counteract the rising of the furnace bottom or delay the rising of the furnace bottom. If the furnace period caused by the rising of the furnace bottom can be prolonged to 10-12 months, the whole production process can realize better commercial operation; (13) The temperature of the reaction zone and the hearth must be high, and the time for which the charge is heated to the reaction temperature must be short, that is, the temperature must be high, a temperature of 2200 ℃ is required, and the rate of heating must be high, so that the residence time is reduced in a temperature region where carbide is easily generated as much as possible; (14) In general, a submerged arc furnace is used for smelting aluminum-silicon alloy, and a deeper hearth, a smaller polar circle diameter and a larger specific power per unit area of the furnace bottom, such as 450-600kw/M2 and a larger specific power per unit volume are needed. (15) The electric furnace power is more than 16500KVA, which is a general proposal given by the global leading institutions in the field of the Soviet Union and the Ukraand, above which the furnace bottom area power intensity and the furnace volume power intensity are both larger; (16) In theory, the direct-current submerged arc furnace is also a good choice, and particularly, the bottom anode is used, the bottom temperature is high, and the bottom is not easy to expand. However, the bottom anode has high manufacturing cost and is easy to damage, so that the furnace is too short in service and the reliability of the electric furnace is insufficient to be abandoned. At present, alternating current ore-smelting electric furnace is still the main part. (17) It has been suggested to add a false hearth made of porous refractory material to allow the liquid ferrosilicon to flow from the false hearth to the bottom of the hearth immediately once it is produced, avoiding carbide formation by contact with carbonaceous reducing agent, and avoiding difficult liquid discharge caused by floating of the produced ferrosilicon alloy above the charge.

Attempts and practices for electrothermal aluminum production have been largely studied and practiced in the united kingdom, france, germany, united states, canada, china, the soviet union and later uk, since about 1880 s. But finally commercialized is the factories of the soviet union, nie Ba and the like, and the Ukraand metallurgical world is inherited later.

The germany-third empire before the end of the second war, the technology can not only produce aluminum-silicon alloy, but also finally obtain structural aluminum alloy, named as Beck technology, but the data which can be provided are not very sufficient.

Despite the great deal of work done by western technology and industry, commercialization is not fully achieved nor does it create any impact on the production of raw aluminum monopoly electrolytic aluminum. The reason for this may be as follows: the western science and technology industrialization system follows a strict step-by-step amplification path of laboratory small-scale trial-pilot-scale trial production, so scientists engaged in research must be on a small laboratory scale to smoothly realize stable output of electrothermal aluminum-silicon alloy, particularly aluminum-silicon containing more than 50%, and then industry will accept trial production of larger electric furnaces. But the electric heating aluminum-silicon alloy is remarkable in that the bottom power density of a small electric furnace cannot meet the temperature and the heating speed due to the extremely high crucible temperature and the rapid heating process, and even an electric furnace of thousands of KVA cannot meet the temperature and the heating speed, as suggested by the Suviet expert, the 16500KVA electric furnace is the lower power limit of equipment capable of stably producing. Because the Germany before the end of the soviet union and the second battle is in military or quasi-military war time system, the economic law of chemical metallurgy of the so-called market economy law or equipment and scale gradual amplification is not strictly complied with, so that the conventional gradual amplification process can be possibly overcome, and an industrial large-scale electric furnace is directly adopted for trial production, thereby obtaining unexpected success. Of course, this is only a reasonable assumption.

The periodic discharge of aluminum-silicon alloys or aluminum-silicon-iron alloys containing relatively high aluminum content, such as 50-65% aluminum, 1.5-10% iron and titanium, and the balance silicon, generally 30-38%, from submerged arc furnaces, is called primary aluminum-silicon alloys, primary alloys, coarse alloys, intermediate alloys, and the like, and if cast aluminum alloys or even wrought aluminum alloys containing lower iron than silicon cannot be extracted, only as low economic value steel deoxidizers or as hot magnesium reduction agents, does not produce the desired industrial primary aluminum for the aluminum industry, which is primarily structural materials.

The initial refining or treatment is to reduce the iron content in the primary alloy as much as possible, for example around 1.5% or even lower, after simple chemical refining of the liquid alloy to remove mixed carbides and oxides, the iron is removed by adding manganese, after which the iron is reduced, diluted with electrolytic aluminium to reduce the silicon content from 30-38% to 10-13%, i.e. to reduce the silicon content of the eutectic aluminium-silicon alloy or hypoeutectic to a silicon-containing level, which means that the primary aluminium-silicon alloy is diluted by a factor of 3-4 with a high-quality high-priced electrolytic aluminium-silicon liquid, which is not cost-effective, so that some of the cost advantages obtained by the electrothermal method are then diluted by a factor of 3-4 with electrolytic aluminium, which cost advantages are offset instead. FIG. 2 is a phase diagram of an aluminum-silicon binary alloy, and it can be seen that silicon in a typical aluminum alloy should not exceed 13%, otherwise it becomes a hypereutectic alloy, and the application range is limited.

The difficulty of smelting low-iron aluminum-silicon alloy is high. The iron content contributes to the reduction of aluminum, silicon. For the alloy containing 20-30% of aluminum, 30-40% of silicon and 20-30% of iron as deoxidizer, the smelting difficulty is not equal to that of the conventional silicon alloy.

In order to smelt low-iron alloys, the raw materials must be carefully selected, low-iron raw materials must be used, the electrodes must be expensive carbon self-baking electrodes, but pre-baking electrodes cannot be used, the latter being self-sintered in a steel shell with electrode paste, at low cost, but with a certain iron content in the product, so that it cannot be used. Once the iron content is higher than 1.5%, the method of adding manganese to remove iron and diluting pure aluminum to reduce silicon cannot be implemented. This approach obviously cannot be used as a subsequent operation for submerged arc furnace smelting.

It is more feasible to select a metal Me which has stronger dissolution capability to aluminum, but has low solubility to silicon and iron elements, so that a selective dissolution method can be adopted, an Al-Me binary alloy is formed by a refining impurity-removing method commonly used for nonferrous metals such as liquation, condensation and the like, the ferrosilicon in the alloy is separated into byproducts, and then, a method is conceivable, such as distillation separation of Al and Me metals by utilizing different vapor pressures. This selective dissolution, or physical "extraction" of the molten metal, requires two steps to accomplish. The first step is dissolution, followed by solid-liquid separation. And secondly, distilling and separating. Alternative Me metals include lead, mercury, zinc, magnesium, and other relatively common metals, all of which have the aforementioned separable characteristics to some extent. Lead and mercury are used as toxic heavy metals, have adverse effects on human health and environment, and are not good choices. Zinc and magnesium are more suitable. Zinc is a large common metal and is reasonably available. But magnesium has a significant advantage over zinc. The main appearance is that: (1) The aluminum-silicon alloy is treated by zinc, the required mass is about 3-4 times that of the aluminum-silicon alloy, and the magnesium only needs about 1 time. This is because zinc has a large atomic weight and a large density, and a large mass multiple is required in terms of atomic number ratio and volume, so that the amount of zinc to be used and circulated is relatively large; (2) zinc is much more expensive than magnesium. In recent 20 years, with the great development of the magnesium industry, particularly the emerging magnesium production country in which China becomes a global 86% magnesium yield, the price of magnesium is often at the same level as that of aluminum loitering, and is even lower than that of zinc. This is more advantageous when magnesium is used as the "extractant". (3) The capability of magnesium for removing iron and silicon in aluminum-silicon alloy is better than that of zinc. Zinc is not able to remove the bound silicon element from aluminum at higher temperatures, and as such magnesium is much more effective. (4) The ferrosilicon solid phase precipitate removed by the aluminum-silicon alloy is entrained with certain aluminum content and is an excellent metal magnesium thermal smelting reducing agent, which means that the thermal aluminum smelting and the thermal magnesium smelting can form a coupling production relationship, the closed loop coupling brings about the improvement and upgrading of the aluminum industry, has a huge pushing effect on the magnesium industry, and can form aluminum-magnesium co-production with win-win aluminum-magnesium. In contrast, when zinc is used for extracting aluminum, zinc is a simple metal for recycling and does not affect the existing zinc smelting industry. (5) The adoption of magnesium as an extractant means that a large-scale light alloy joint factory forms benign interaction between aluminum-magnesium industry plates. The reducing agent is changed from ferrosilicon to ferrosilicon, and the reducing capability of aluminum is stronger than that of silicon, so that the energy consumption, material consumption and production period of magnesium smelting are greatly improved compared with the pure ferrosilicon. Moreover, the existing chemical refining of magnesium is omitted, crude crystallized magnesium is used as an extracting agent to extract pure aluminum, the purity of magnesium vapor which is originally contraindicated in the magnesium smelting process is not needed to be considered much, the high-temperature high-vacuum process can be adopted to strengthen the rapid smelting, the magnesium smelting period is shortened, even if the magnesium contains high silicon, aluminum and iron content, the content of impurity elements silicon, aluminum and iron is not considered enough, and the impurity elements silicon, aluminum and iron become useful products in the subsequent aluminum-silicon-magnesium mutual smelting stage.

Magnesium is a preferred molten metal for dissolving aluminum due to its special properties; the liquid phase can be infinitely miscible with aluminum, as shown in the aluminum-magnesium binary alloy state diagram of fig. 3, but hardly dissolves iron and silicon. FIG. 4 is a graph showing the very small amount of soluble iron in magnesium-based alloy solutions, which can be considered as a good metal for low iron in the general nonferrous metals industry. Fig. 5 shows the solubility of silicon in magnesium, and the content of soluble silicon element in magnesium is low due to the formation of Mg2Si compound, and particularly, silicon element and magnesium form a compound to precipitate out as the temperature decreases. But magnesium and aluminum can be infinitely and mutually dissolved in liquid state, the eutectic interval is larger, the eutectic temperature is as low as about 480 ℃, and compared with the melting temperature of pure metal aluminum magnesium, the melting temperature is reduced by nearly 200 ℃, which means that the soluble iron and silicon are further thoroughly removed.

The magnesium dissolves aluminum and is separated from ferrosilicon by a condensation method or a liquation method. From the angle of energy utilization, the temperature of the hot aluminum-silicon-iron alloy liquid from the submerged arc furnace is up to 1300-1500 ℃, and after refining, the temperature is reduced to a certain extent, but still remains in a high-temperature liquid state, thus being suitable for a condensation method. And (3) drying and preheating coarse magnesium or waste magnesium, then melting or carefully mixing the coarse magnesium or waste magnesium with aluminum-silicon-iron liquid, and then cooling to a certain temperature which can be up to 480 ℃ or higher than the liquidus line of aluminum-magnesium. The adding amount of magnesium is preferably 0.5-2 times of that of the aluminum-silicon-iron alloy liquid, and the more the magnesium amount is, the more thoroughly the purification, iron removal and silicon reduction are. After cooling and condensing, only relatively pure aluminum-magnesium alloy liquid is maintained in a liquid state, and iron elements are combined with aluminum to form complex aluminum-iron metal compounds and aluminum-silicon-iron metal compounds, typically FeAl3, which means that iron is combined with about 1.5 times of metal aluminum, as shown in an aluminum-iron binary state diagram shown in fig. 6. The silicon element is combined with magnesium to form Mg2Si, and the melting point is up to above 1000 ℃, so that the solid phase precipitate is mainly FeAl3 and Mg2Si, the density of the solid phase precipitate is larger than that of the aluminum magnesium alloy liquid, and the density of magnesium silicide is not obviously different from that of the aluminum magnesium alloy liquid. FIG. 7 shows that the ternary alloy of aluminum, magnesium and silicon combines magnesium with silicon to form magnesium silicide at 550℃, while the aluminum magnesium forms a liquid alloy.

The method for separating the silicon-aluminum alloy liquid from the solid phase precipitate dispersed therein has various methods, and the common solid-liquid separation method has certain effect. Such as gravity sedimentation, vacuum filtration, pressure filtration, spiral electric heating crystallization machines on inclined planes used in the nonferrous tin industry, etc. However, the most effective solid-liquid separation is supergravity centrifugal separation. The solid and liquid can be centrifugally separated by adopting centrifugal sedimentation or centrifugal filtration. For aluminum magnesium alloy liquid and solid phase precipitate with large proportion, centrifugal filtration is suitable. Compared with natural gravity sedimentation, centrifugal separation can achieve many times of gravity by the centrifugal force of solid phase particles, and the effect of strengthening separation is achieved. The ratio of centrifugal force to gravity of solid phase particles is generally defined as separation factor, and can be calculated by simple formula in engineering

Where Fc represents a multiple of centrifugal force to gravity, dimensionless. r is the centrifugal radius in meters. Omega is angular velocity, dimensionless. N is the rotation speed per rpm, how many revolutions per minute.

In the pyrometallurgical industry, the separation factor is 556, i.e. the centrifugal force is up to 556 times the force of gravity, provided that the centrifuge speed is 1000rpm, i.e. 1000rpm, for centrifugal filtration of the aluminium-magnesium alloy liquid or for centrifugal casting of other black or coloured alloys, the drum diameter is 1 meter.

Compared with a horizontal cantilever centrifuge and a horizontal riding wheel type centrifuge, the vertical centrifuge can adopt a larger centrifugal radius, and is more beneficial. The centrifugation process can be completed in 10-20 minutes generally, but the earlier cooling condensation and the later finishing process are time-consuming, and in order to improve the utilization rate of the centrifugal machine, one centrifugal machine is adopted to be matched with a plurality of centrifugal rotary drum modes. The centrifugal rotary drum is of a concentric double-rotary drum structure, a core cavity of the innermost layer is used for containing aluminum-silicon-iron-magnesium quaternary alloy liquid, then after the steel rotary drum is contacted with the hot alloy liquid, heat is absorbed, the alloy liquid is cooled relatively quickly to generate a condensation effect, after the rotary drum absorbs heat and radiates heat outwards for a period of time, the temperature is close to a set separation temperature, such as 530 ℃, the whole centrifugal rotary drum is placed into a centrifugal machine and locked, the centrifugal machine is started, so that aluminum-magnesium alloy liquid is thrown out from a liquid throwing hole, and solid-phase silicon-aluminum-iron and magnesium silicide combined magnesium is reserved in the inner barrel as filter residues. It should be noted that the liquid throwing holes on the inner wall of the centrifugal rotary drum are not used for solid-liquid separation, but are actually used for solid-liquid separation, and are network structures formed by the bridging action of crystals among precipitated solid-phase substances, so that the aluminum-magnesium alloy liquid is filtered. The macroscopic scale liquid throwing holes are only channels for liquid alloy to flow out, and are not filter media, and the truly functioning filter media are microstructure combined by precipitated solid phases.

Through the cooling condensation-centrifugal separation process, most of iron and silicon elements exist in the filter residue in a solid phase form, and filtrate is relatively pure aluminum-magnesium large-proportion alloy liquid, and the melting point is lower, and the minimum temperature is lower than 480 ℃. The mutual separation of aluminum and magnesium is realized by distillation. The lower the temperature of the condensate, the lower the iron and silicon in the aluminum-magnesium alloy liquid, but in industrial production, the temperature of the condensate and centrifugal separation is set according to the actual product requirement, and the separation process shown in fig. 8 is not needed to be adjacent to the solidification line of aluminum-magnesium, so that the iron and silicon content in the liquid phase gradually reduces to a very low level in the aluminum-magnesium alloy liquid phase along with the temperature reduction.

The vapor pressure of the metal increases with increasing temperature. The vapor pressure of the metal can be calculated from the following formula.

lgp＝AT ^-1 +BlgT+CT+D

Where P is the vapor pressure Pa, T is the absolute temperature, and A, B, C, D is a constant. Vapor pressure of aluminum and magnesium is as follows

lgp _Al ＝-16380/T-1.0lgT+14.445

lgp _Mg ＝-7550/T-1.411gT+14.915

With reference to tables 2 to 4, the vapor pressures of aluminum and magnesium were calculated as follows. As a comparison, magnesium is a volatile metal with vapor pressures 5-8 orders of magnitude greater than aluminum. This shows that distillation can be used to allow for a more thorough separation of the aluminium and magnesium. That is, when the aluminum magnesium alloy liquid is heated at high temperature, magnesium volatilizes out of the alloy molten pool, and magnesium vapor is cooled in an additional condensing space to be condensed into liquid or solid state, so that the aluminum magnesium alloy liquid is separated from the residual aluminum liquid in the original molten pool.

Table 2 vapor pressure comparison of magnesium to aluminum and multiples thereof

Temperature in degrees centigrade	Absolute temperature of	Mg vapor pressure (Pa)	Al vapor pressure (Pa)	Multiple times
					650	923	3.58E+02	5.41E-07	6.62E+08
700	973	8.75E+02	4.19E-06	2.09E+08
					750	1023	1.95E+03	2.65E-05	7.37E+07
800	1073	4.03E+03	1.41E-04	2.86E+07
					850	1123	7.78E+03	6.43E-04	1.21E+07
900	1173	1.42E+04	2.58E-03	5.49E+06
					950	1223	2.45E+04	9.21E-03	2.66E+06
1000	1273	4.04E+04	2.97E-02	1.36E+06
					1050	1323	6.41E+04	8.76E-02	7.32E+05
1100	1373	9.82E+04	2.38E-01	4.12E+05

TABLE 3 vapor pressures of metallic magnesium and various impurity elements

Saturated vapor pressure of metal magnesium and each impurity element at different temperatures

TABLE 4 lower limit of content of main impurity element in magnesium by distillation

The lowest content/%of each impurity element in the metal magnesium can be achieved through distillation at different temperatures

The vapor pressure of the binary alloy liquid composed of aluminum and magnesium is reduced compared with that of pure metal, and negative deviation of activity coefficients is formed due to interaction among aluminum and magnesium alloys as well as concentration reduction, so that the vapor pressures of aluminum and magnesium are accelerated to be reduced in a nonlinear degree, and the activity coefficients are shown in table 5.

TABLE 5 Al-Activity coefficient of Mg component (temperature: 800 ℃ C.)

N _Al	1.00	0.9	0.8	0.7	0.6	0.5	0.4	0.3	0.2	0.1	0.0
												γ _Al	1.000	0.971	0.900	0.817	0.732	0.658	0.599	0.555	0.530	0.522	0.526
γ _Mg	0.168	0.301	0.464	0.623	0.763	0.871	0.942	0.982	0.997	1.000	1.000

The density ratio of aluminum to magnesium in the gas phase can be calculated according to the following formula, where N is the mole fraction, P is the vapor pressure, and M is the molar mass.

From the above formula estimation, it is known that at 1000 ℃, even if the magnesium content in the aluminum magnesium alloy liquid is reduced to 1wt.%, the activity coefficient of magnesium is reduced to 0.168, and because the vapor pressure of magnesium at this temperature is still 136 ten thousand times that of aluminum, the instantaneous magnesium mass in the gas phase is still up to more than 2000 times that of aluminum, meaning that the content of aluminum in this instantaneous gas phase is still less than 0.05%, it is demonstrated that purer metallic magnesium can be obtained from the condensed gas phase product, so that the aluminum magnesium is more thoroughly separated.

The rate of metal evaporation per unit area can be calculated by the following formula

Wherein ω is evaporation rate, g/cm ² /hr；

The coagulation coefficient α is at most 1, typically a fraction of less than 1;

p _Pa vapor pressure in Pa;

m, molar mass.

The calculated evaporation rates of pure magnesium are shown in table 6 below. The actual evaporation rate is less than this theoretical value. As the concentration of magnesium decreases during evaporation of the aluminum magnesium alloy liquid, the vapor pressure of magnesium decreases nonlinearly, resulting in a true evaporation rate of less than 1% of the theoretical value of pure metal, for example, in an aluminum magnesium alloy liquid containing 1wt% magnesium, the vapor pressure of magnesium is about 1/600 of that of pure metal, and thus the evaporation rate also decreases drastically. By increasing the evaporation area, increasing the temperature and improving the vacuum degree, the evaporation rate can be accelerated, and the production efficiency is ensured. In addition, the metal evaporation has a critical pressure, the vacuum degree is lower than the critical pressure, the evaporation rate reaches the maximum value at the temperature, the vacuum degree is continuously increased, the increasing rate is not increased, and the vacuum degree is not required to be lower than the critical pressure in the industrial production too much as shown in fig. 9.

TABLE 6 evaporation rates of magnesium metal at different temperatures

Temperature (. Degree. C.)	500	600	700	800	900	1000
							Evaporation rate (g.cm) ^-2 ·h ^-1 )	1.68	17.5	110	484	1620	4450

The aluminum content of the condensate varies in the evaporated gas phase depending on the temperature of evaporation. If the purity of the magnesium sought for distillation is higher, lower temperatures are required, with a corresponding lower evaporation rate, but lower yields. In commercial processes, where a high evaporation rate is required to maintain plant throughput, there is some aluminum content in the distilled magnesium. If magnesium is recycled as extractant, aluminum does not affect its use. If sold as a by-product to the outside, pure magnesium or high-purity magnesium cannot be used as an aluminum-containing magnesium alloy, for example, an aluminum-containing magnesium alloy of AZ series, which is an alloy product widely used.

In the residual aluminum liquid, when the magnesium content is reduced to a relatively low level, for example, 0.2%, the rate of continuing the distillation is greatly reduced, and at the same time, the evaporation amount of aluminum is relatively increased. To this concentration, three approaches are desirable: introducing argon into the aluminum liquid at the bottom of the distillation pot to continue distillation, and distilling out more magnesium in the bubble volume of the argon blowing until the magnesium content is ultralow; and secondly, stopping distillation, removing or replacing magnesium in the residual aluminum liquid by adopting a chemical refining method after the residual aluminum liquid flows out, such as chlorine, aluminum chloride, sodium fluoroaluminate and the like, and replacing aluminum and magnesium mutually to oxidize magnesium into molten salt. Thirdly, a certain aluminum content is reserved, so that the distillation residual liquid is used as a magnesium-containing aluminum alloy or an aluminum alloy of silicon and magnesium, and is also a commonly used aluminum alloy type.

Although aluminum magnesium alloy can be well separated through distillation, the current practice of small amount of metal magnesium distillation is limited to batch equipment and processes, such as waste magnesium recovery, high purity magnesium preparation and distillation recovery of redundant magnesium in the production of titanium sponge, wherein solid or liquid magnesium is placed in a sealed crucible which can be heated, and the magnesium is evaporated into a condensing chamber or a condensing area through continuous heating and vacuumizing, so that pure magnesium is collected after condensation. The whole process has no flow of molten metal, so that the evaporation area is very small, intermittent production is necessarily carried out, the distillation is finished, vacuum is broken, crystallized pure magnesium is taken out for subsequent treatment, the production rhythm is discontinuous, the efficiency is low, and equipment cooling caused by vacuum breaking and vacuum recovery brings about reduction of energy efficiency, and no continuous flow separation of two molten metals to be separated is carried out, so that the requirement of mass production is difficult to meet.

The filter residue remaining in the centrifugal filtration is mainly composed of almost all iron elements, most silicon elements, a certain amount of aluminum elements combined by iron, a certain amount of magnesium elements combined by silicon, and the like, and can be called ferrosilicon filter residue. Wherein the main phase comprises FeAl3 metal compound, mg2Si, feSiAl, crystalline Si and the like. The ferrosilicon filter residue is most suitable to be used as a reducing agent for smelting magnesium by a thermal method or can be used as a composite deoxidizer in the iron and steel industry. If the customer does not need magnesium in the composite deoxidizer for steel, the magnesium is distilled and recovered in vacuum to obtain the ferro-silico-aluminum, and even the content of the iron needs to be remelted and increased so as to enable the density and the composition to meet the requirements of steel users.

As a reducing agent for smelting magnesium by a thermal method, the reducing agent is used for replacing commonly used #75 ferrosilicon, is suitable for a transverse tank reduction process of a Pidgeon method, even in a vertical tank process, a resistance internal heating process and an arc melting reduction process, and has stronger reducing capability than ferrosilicon. The method has the specific advantages that: (1) Magnesium is carried by the reducing agent, namely Mg2Si, and can be separated out only by physical distillation under high-temperature vacuum; (2) The reducing agent contains aluminum, so that the magnesium element reduction rate, the reduction energy consumption, the ferrosilicon surplus, the reduction temperature, the reduction vacuum degree and the like of magnesium smelting are all superior to those of pure ferrosilicon; (3) The iron content in the reducing agent is far lower than 25% level in #75 ferrosilicon, so that various indexes of reduction are further improved; (4) The crude magnesium is directly transported to an aluminum smelting workshop for remelting without refining, so that the refining cost is reduced; (5) Crude magnesium is refined by conventional fluoride, has heavy pollution and faces great risks of strict control limit in the aspect of environmental protection laws and regulations; (6) The dust of electric heating aluminum smelting contains aluminum silicon metal powder, which can be used as magnesium smelting reducer; mgO+CaO contained is dolomite magnesium ore micropowder, and returns to a magnesium factory to be used as a raw material for smelting magnesium, so that the economical efficiency of smelting magnesium is further improved; (7) The most important reduction process can adopt a high-temperature and high-speed reduction process, the fact that the impurity content of aluminum, silicon and iron in crude magnesium exceeds the standard is not considered, the metal impurities cannot be removed by the original fluoride chemical refining, the aluminum magnesium co-production of the metal impurities is a product which can be utilized, low-speed smelting quality is not needed, and the production efficiency can be improved by 50-100%.

The silicon-heat method is used for smelting magnesium by solid reduction, the original smelting period is 12 hours, and a smelting mode of medium temperature, medium vacuum and low speed is adopted to ensure the quality of products, so that the exceeding of silicon, aluminum and iron elements in magnesium ingots is prevented. In the invention, vacuum distillation is adopted to purify magnesium, the front magnesium ingot needs to be mutually fused with aluminum-silicon-iron alloy, and all metal impurities in the magnesium are recycled. Therefore, the aluminum-magnesium combined production realized by the invention breaks through a low-speed mode of magnesium smelting by the Pidgeon process, adopts a process strengthening three-high mode of 'high temperature high vacuum high speed', reduces energy consumption, reduces material consumption, shortens reduction time, reduces labor cost and gas cost, and simultaneously increases productivity, labor productivity and investment. The whole process flow of the electric heating aluminum smelting and the metal magnesium co-production is shown in figure 10.

Drawings

FIG. 1 is a schematic diagram of the overall process of electroheat aluminum production;

FIG. 2 is a state diagram of an aluminum-silicon binary alloy;

FIG. 3 is a state diagram of an aluminum-magnesium binary alloy;

FIG. 4 is the solubility of iron in magnesium-based alloys;

FIG. 5 is a state diagram of a magnesium-silicon binary alloy;

FIG. 6 is a state diagram of an Fe-Al binary alloy;

FIG. 7 is a state diagram of an aluminum-magnesium-silicon ternary alloy;

FIG. 8 shows the effect of removing iron and silicon by liquid phase condensation and centrifugal separation;

FIG. 9 is a graph of critical vacuum for metal distillation rate;

FIG. 10 is a schematic diagram of a thermal aluminum magnesium co-production process flow;

FIG. 11 is a diagram of a centrifugal separation and distillative separation process;

FIG. 12 is a schematic diagram of an apparatus for an aluminum magnesium centrifuge;

FIG. 13 is a schematic diagram of the process of centrifugal separation of aluminum and magnesium;

FIG. 14 is a measurement of iron and silicon removal by centrifugation;

FIG. 15 is a schematic view of an apparatus for a continuous distillation and separation furnace for aluminum and magnesium in example 1;

FIG. 16 is a schematic view of a distillation tray apparatus;

FIG. 17 is a schematic view of a vertical stack of distillation trays;

FIG. 18 is a diagram of an internal heat type double shell distillation furnace body in example 3;

FIG. 19 is a schematic view showing an apparatus of an aluminum-magnesium continuous distillation separation furnace in example 3;

in the figure: 301. aluminum-magnesium centrifuge 302, centrifuge fixed bowl wall 303, centrifuge fixed bowl protective cover 310, centrifuge bowl 311, centrifuge bowl bottom plate 312, centrifuge bowl outer bowl wall 313, centrifuge bowl inner bowl wall 314, centrifuge bowl top plate 317, centrifuge bowl inner bowl chamber 318, centrifuge bowl annular liquid receiving tank 319, centrifuge bowl liquid injection channel 320, liquid throwing hole 330, raw aluminum-silicon-iron-magnesium quaternary alloy liquid 340, aluminum-magnesium alloy filtrate 350, silicon-iron filter residue 601, regenerative heating furnace 602, heat accumulator and air channel 611, aluminum-magnesium alloy remelting furnace 612, aluminum-magnesium alloy block 613, aluminum-magnesium alloy liquid 614, vacuum pipette 621, magnesium distillation column 622, distillation tray 623, aluminum liquid down-flow tube 624, pure aluminum liquid 625, aluminum liquid holding furnace 626, aluminum liquid dosing pump 630, magnesium vapor 631, magnesium condenser 632 negative pressure spray vaporization chamber 633, atomizing water spray head 634, vaporization negative pressure suction pipe and vacuum pump 641, spiral magnesium scraper 642, magnesium vapor baffle 643, crystallized magnesium locking upper valve 645, crystallized magnesium locking lower valve 646, crystallized magnesium storage chamber 650, total vacuum pipeline and vacuum pump 651, pure magnesium liquid 652, magnesium liquid metering pump 653, magnesium remelting furnace 661, vacuum suction pipeline 662, broken vacuum charging pipeline 701, outer shell 702, hot flue gas inlet 703, flue gas outlet 720, refractory insulating layer 721, inner shell 722, hot flue gas pipeline distillation tray 763, interlayer vacuum pipeline 802, aluminum magnesium liquid junction region 803, aluminum magnesium liquid drop hole 804, enclosure 805, runner cofferdam 806, aluminum magnesium liquid runner 807, aluminum magnesium liquid return flow direction 821, kth stage distillation tray 822, kth stage distillation tray junction region 823, the k-stage distillation tray drop hole 828, the k-stage distillation tray liquid receiving position 831, the k+1-stage distillation tray 832, the k+1-stage distillation tray liquid receiving region 833, the k+1-stage distillation tray drop hole 838, the k+1-stage distillation tray liquid receiving position 848, the k+2-stage distillation tray liquid receiving position P1, the double-shell distillation furnace working vacuum pressure P2, and the double-shell distillation furnace interlayer buffer pressure.

Detailed Description

The invention is further described below with reference to examples and figures.

Example 1:

the method comprises the steps of proportioning high-alumina fly ash and bauxite tailings to reach an aluminum-silicon ratio of 1.5, adding stoichiometric bituminous coal as a carbonaceous reducing agent, adding aluminum, silicon and iron oxides in ash brought by the bituminous coal, fully mixing and grinding, kneading and pressing balls by using pulp waste liquid as a binder, drying to prepare a furnace charge with certain strength, adding the furnace charge into a 16500KVA modified alternating current ore furnace, carrying out electrothermal reduction to prepare an aluminum-silicon-iron alloy liquid, carrying out liquid outlet temperature of about 1500 ℃, mixing with certain carbide and unreduced oxide, and carrying out mixed halide salt refining to obtain the initial aluminum-silicon-iron alloy containing 10%, silicon containing 30% and aluminum containing 60%. The electricity consumption of each ton of aluminum-silicon-iron ternary alloy is 13000kwh.

The ternary alloy liquid and the collected crude magnesium are mutually fused: preheating and drying crude magnesium in an aluminum-magnesium intermelting furnace, adding a small amount of ternary alloy liquid in batches, stirring and standing, and after a period of time, completely mixing, wherein the amount of the final ternary alloy liquid is 1000kg, the crude magnesium is 1200kg, and slowly heating to 1000 ℃. The overall flow is shown in fig. 11.

Fig. 12 is an apparatus and connection layout of a centrifugal separation section, and fig. 13 is a sectional view of a centrifugal separation process. The mixed Al-Si-Fe-Mg quaternary alloy liquid is poured into the inner cavity 317 of the centrifugal drum through the liquid pouring channel 319 of the centrifugal drum, and the centrifugal drum 310 is at a liquid pouring station and is not arranged on the Al-Mg centrifugal separator 301. The top plate 314 of the centrifugal drum is covered and inert gas is filled to protect the original aluminum silicon iron magnesium quaternary alloy liquid 330 in the inner cavity 317 of the centrifugal drum from being contacted with the outside, so as to protect the magnesium from being oxidized by air. The inner wall 313 of the centrifugal drum and the bottom plate 311 of the centrifugal drum absorb the heat of the quaternary alloy liquid to raise the temperature, and after a period of time, the mixture is kept stand until the temperature is uniform and the predetermined temperature is reached, for example, 530 ℃, the whole centrifugal drum 310 is lifted, placed inside the fixed wall 302 of the centrifugal drum, and the fixed cover 303 of the fixed drum is covered for fixing. The aluminum-magnesium centrifuge 301 is then started to spin at a speed of 1000 rpm.

The diameter of the inner cavity 317 of the centrifugal drum 310 is 1 m, the height of the inner wall 313 of the centrifugal drum is 700mm, the total volume is about 540 liters, the primary aluminum-silicon-iron-magnesium quaternary alloy liquid 330 is 700 kg at one time, and a certain free space is reserved. The liquid throwing holes 320 are through holes, the hole patterns are round table-shaped from inside to outside, the innermost diameter of the holes is 6mm, the outermost diameter of the holes is 8mm, the holes are uniformly distributed on the inner cylinder wall 313 of the centrifugal cylinder, and the total area of the holes occupies 10-15% of the outer surface area of the inner cylinder wall 313 of the centrifugal cylinder.

The aluminum-magnesium centrifugal separator 301 rotates to perform solid-liquid separation operation, and lasts for 15 minutes after reaching 1000rpm, at this time, solid phase particles separated out from the original aluminum-silicon-iron-magnesium quaternary alloy liquid 330 comprise almost all iron and silicon elements, part of aluminum and magnesium elements combined with the iron and silicon, and the rest is low-melting-point low-iron low-silicon aluminum-magnesium alloy liquid, and under the action of centrifugal force, the aluminum-magnesium alloy aluminum liquid is thrown out from a solid phase particle gap to move away from a rotation center, reaches a centrifugal drum annular liquid receiving groove 318 through a liquid throwing hole 320, continuously shoots outwards to collide with the outer drum wall 312 of the centrifugal drum, is condensed by cooling after contacting with the outer drum wall 312 of the centrifugal drum, adheres to the outer drum wall 312 of the centrifugal drum, at this time, aluminum-magnesium alloy filtrate 340 is accumulated in the annular liquid receiving groove 318 of the centrifugal drum, and is physically separated from silicon-iron filter residues 350 remained in the inner cavity 317 of the centrifugal drum.

The original aluminum-silicon-iron-magnesium quaternary alloy liquid 330 is sampled and analyzed before cooling and condensing, the iron content is 4.55 percent, the silicon content is 13.64 percent, and the aluminum-silicon-iron quaternary alloy liquid is sampled and analyzed from the aluminum-magnesium alloy filtrate 340 after centrifugal separation operation, wherein the iron content is 0.01 percent and the silicon content is 0.24 percent, which indicates that the aluminum element in the original aluminum-silicon-iron is thoroughly separated from the silicon and the iron. The total measurement result is that the amount of the original aluminum-silicon-iron-magnesium quaternary alloy liquid 330 is 2200kg, the aluminum-magnesium alloy filtrate 340 is 1150kg after centrifugal separation, the rest is ferrosilicon filter residue 350, and a small amount of oxidation loss of magnesium-aluminum is also counted in the ferrosilicon filter residue 350.

Through centrifugal separation, 600kg of aluminum element is added into the aluminum magnesium alloy filtrate 340, and the rest is in the ferrosilicon filter residue 350, so that the extraction rate of aluminum reaches 76.7%.

After the obtained aluminum magnesium alloy filtrate 340 is condensed, the aluminum content is 41%, the magnesium content is 58.7%, the silicon content is 0.24%, and the iron content is only 0.01%, so that the iron and silicon removal result is shown in fig. 14. The large-proportion aluminum magnesium alloy has four kinds of applications even without distillation separation. The large-proportion aluminum-magnesium alloy is very fragile, is not like common metal objects any more, is more similar to ceramic in nature, is particularly easy to mechanically crush and grind into fine powder, is very easy to be sticky when common aluminum alloy or magnesium alloy is prepared into powder through mechanical processing, is not easy to be processed into very fine powder, has better usability in occasions needing aluminum-magnesium powder, such as the fields of military industry, civil fireworks and crackers and the like, and can be sold to enterprises manufacturing aluminum-magnesium alloy powder by adding certain aluminum or magnesium after remelting or presetting corresponding components of aluminum-magnesium alloy filtrate 340 when magnesium is added in the earlier stage if the proportion of aluminum-magnesium in the aluminum-magnesium alloy has further specific requirements.

The more common and suitable thorough practice on a large industrial scale is to use a continuous distillation furnace to achieve complete aluminum and magnesium finishing separation of the coagulum of the almag filtrate 340.

The centrifuge fixing cylinder protecting cover 303 of the aluminum-magnesium centrifuge 301 is opened, the whole centrifuge cylinder 310 is taken out from the centrifuge fixing cylinder wall 302, and the whole centrifuge cylinder 310 is moved to a cleaning station of the centrifuge cylinder 310 to empty the aluminum-magnesium centrifuge 301 for the next alloy liquid to be separated and the centrifuge cylinder 310 containing the alloy liquid. The centrifuge bowl top plate 314 is opened and the coagulum of the almag filtrate 340 in the centrifuge bowl annular sump 318 is manually removed or a mechanical tool is ejected for distillative separation. At the same time, the ferrosilicon filter residue 350 remaining in the inner cavity 317 of the centrifugal drum is manually taken out or ejected out by a mechanical tool as a byproduct, a composite deoxidizer for steel production, and a reducing agent for magnesium smelting by a thermal method, or proper composition adjustment is carried out before the application.

The condensate of the main product aluminum magnesium alloy filtrate 340 enters a distillation separation link, as shown in fig. 15. The solidified cake or sheet of the almag filtrate 340 is put into the almag remelting furnace 611 as a distillation step, at this time, a certain amount of almag liquid 613 remains in the almag remelting furnace 611, as a continuous production process, a certain amount of melted almag liquid 613 remains in the crucible of the almag remelting furnace 611, and the newly put almag block 612 is melted in the existing almag liquid 613. In this embodiment, the aluminum-magnesium alloy remelting furnace 611 is placed in the regenerative heating furnace 601, and the energy efficiency of gas heating in the regenerative heating furnace 601 is ensured to be higher through the switching use of the heat accumulator and the air channel 602.

The aluminum-magnesium alloy liquid 613 contained in the aluminum-magnesium alloy remelting furnace 611 is pumped into the magnesium distillation tower 621 through a vacuum liquid suction pipe 614, naturally flows downwards from the top or the middle upper part of the magnesium distillation tower 621, falls through repeated baffling, is paved on the multi-stage distillation tray 622 to form a thin layer of the aluminum-magnesium alloy liquid, is heated to evaporate magnesium and enters a gas phase, and magnesium vapor leaves the magnesium distillation tower 621 from the magnesium vapor pipe 630 under the vacuum pumping effect and enters the magnesium condenser 631 to be condensed into a liquid state or a solid state. In this embodiment, the magnesium distillation tower 621 is placed in the heat accumulating type heating furnace 601, the magnesium distillation tower 621 is made of heat-resistant steel, the outer wall is heated by flame or hot air, the temperature is kept at 900-1000 ℃, the internal vacuum degree is absolute pressure 0.1-133Pa, and the vacuum system forms continuous pumping force on the magnesium distillation tower 621 through the total vacuum pipeline and vacuum pump 650, the magnesium condenser 631 and the magnesium vapor pipe 630 which are connected in series.

Distillation tray 622 of FIG. 16 is a disk-shaped device for evaporating aluminum-magnesium liquid, vertically stacked in a magnesium distillation column 621, for allowing aluminum-magnesium alloy liquid 613 to flow down and flat onto the tray for evaporation, and allowing the residual liquid to continue to flow down. On each distillation tray 622, a baffle 804 is arranged at the periphery, the height is 30-60mm, one side of the distillation tray 622 is provided with an aluminum magnesium liquid receiving area 802, the other side is provided with an aluminum magnesium liquid dropping hole 803, aluminum magnesium alloy liquid 613 flowing down from the upper distillation tray 622 falls into the aluminum magnesium liquid receiving area 802, then flows in a zigzag manner along an aluminum magnesium liquid flow channel 806 restrained by a flow channel cofferdam 805 according to the direction indicated by the turning flow direction 807 of the aluminum magnesium liquid until the aluminum magnesium liquid is fully paved and passes through the surface of the whole distillation tray 622, and finally flows to the lower distillation tray 622 from the aluminum magnesium liquid dropping hole 803 on the other side.

Each layer of distillation trays 622 is positioned opposite the aluminum magnesium liquid drop holes 803 of the next layer of distillation trays 622, as shown in fig. 17, with the kth stage of distillation trays 821 above the kth +1 stage of distillation trays 831, and aluminum magnesium alloy liquid 613 drops to the kth stage of distillation tray drop zone 822 first, then flows through all of the channels of the kth stage of distillation trays 821, finally drops from the kth stage of distillation tray drop holes 823 to the kth +1 stage of distillation tray drop zone 832, as indicated by the kth +1 stage of distillation tray drop zone 838, gradually flows from the kth +1 stage of distillation tray drop zone 832 through each of the channels of the layer, and finally flows down from the kth +1 stage of distillation tray drop holes 833, as indicated by the kth +2 stage of distillation tray drop zone 848. The distillation tray 622 may be made of graphite, ceramic, or a composite material, such as a structure with a carbide or nitride coating coated on the surface of heat-resistant steel, which is resistant to corrosion by high-temperature aluminum liquid or magnesium liquid.

While the aluminum magnesium alloy liquid 613 flows through each distillation tray 622, the magnesium vapor is continuously heated and evaporated, and leaves the aluminum magnesium alloy liquid 613, so that the magnesium concentration in the aluminum magnesium alloy liquid 613 is continuously reduced, the magnesium concentration is very low and even close to zero after reaching the distillation tray 622 at the lowest layer, the residual aluminum liquid 624 is remained, the residual aluminum liquid flows into the aluminum liquid heat preservation furnace 625 through the aluminum liquid forward flow pipe 623, and the aluminum liquid heat preservation furnace 625 is communicated with the atmosphere and is in a normal pressure state. The liquid level of the pure aluminum liquid 621 in the aluminum down-flow pipe 623 and the magnesium distillation column 621 should be about 3.5-5 meters so that the aluminum liquid column can help maintain the vacuum, i.e., the liquid column seal, in the magnesium distillation column 621. In the low altitude plain area, the air pressure is higher, the height of the liquid column is about 4.5 meters, and in the high altitude plateau area, the air pressure is lower, and the height of the liquid column is about 4 meters. The pure aluminum liquid 624 contained in the aluminum liquid holding furnace 625 can be directly refined and alloyed in situ, or can be directly removed by a device such as an aluminum liquid quantifying pump 626 or a vacuum ladle, and transported to the next link in a liquid state for downstream deep processing. In this example, the inside diameter of the magnesium distillation column 621 is 700mm, the inside height is 4 m, heat resistant steel is used, the diameter of the built-in distillation tray 622 is slightly smaller than that of the magnesium distillation column 621, 35 layers of distillation trays 622 are used, the total evaporation area is 11 square meters, and about 150kg of magnesium can be distilled per hour.

Regarding the flow rate control of the vacuum pipette 614, the flow rate is generally determined by a method of theoretical design in advance and correction by industrial production. The vacuum pipette 614 is provided with a control mechanism capable of opening and closing, and is capable of controlling the amount of the fluid flow. The size of the valve on the vacuum pipette 614 can be determined by several attempts at a given distillation temperature and vacuum. By setting the flow from large to small or from small to large, the proportion of magnesium in the pure aluminum liquid 624 flowing out of the tail end of the aluminum liquid forward flow pipe 623 is sampled and analyzed, and if the magnesium content exceeds the set value, the set flow is too large, and the callback is required to be reduced.

In the regenerative heating furnace 601, a plurality of magnesium distillation columns 621 may be provided to operate simultaneously. In this embodiment, in order to reduce the cost of the distillation energy, gas heat accumulating combustion heating, i.e., external heating for the magnesium distillation tower 621, non-contact type insulation heating is necessary. Thus, the magnesium distillation tower 621 is subjected to a pressure of approximately one atmosphere by the difference between the inside and outside and also subjected to a high temperature of about 1000 ℃, and the magnesium distillation tower 621 is generally formed in a cylindrical shape, and the diameter is not preferably large, for example, a diameter of 700-1000mm, and if it is too large, a thickened heat-resistant steel shell is required, so that the manufacturing cost is high and the heat transfer resistance is also large, and therefore, it is preferable to adopt an arrangement in which a plurality of magnesium distillation towers 621 are juxtaposed in one regenerative heating furnace 601.

The vaporized magnesium vapor enters the magnesium condenser 631 through the magnesium vapor tube 630 and the residual non-condensable gases bypass one of the magnesium vapor baffles 642 to the main vacuum line and vacuum pump 650. The magnesium condenser 631 shell is a device for keeping low temperature, water cooling can be adopted, in order to save water and better control temperature, a negative pressure spray vaporization chamber 632 is adopted, one or more atomized water spray nozzles 633 are arranged in the negative pressure spray vaporization chamber 632, when the temperature of the magnesium condenser 631 needs to be reduced, the atomized water spray nozzles 633 are opened to spray water mist into the negative pressure spray vaporization chamber 632, the negative pressure spray vaporization chamber 632 is connected with a vaporization negative pressure suction pipe and a vacuum pump 634, the inside is negative pressure or vacuum, the water and the water mist in the negative pressure evaporation chamber are evaporated in a negative pressure state lower than one atmosphere, the evaporation temperature is lower than 100 ℃, the vacuum degree is set to ensure that the water evaporation temperature is lower than 70 ℃, no scale formation is caused, a great amount of heat is absorbed by the water evaporation, the temperature of the magnesium condenser 631 shell is reduced, and the metal magnesium vapor can be continuously condensed in the magnesium condenser 631. The magnesium vapor is condensed into solid crystals on the inner wall of the magnesium condenser 631, more and more, in order to maintain continuous production, a spiral magnesium scraper 641 is arranged in the middle of the magnesium condenser 631, similar to a rotating spiral scraper, the crystallized magnesium condensed on the wall is scraped by a spiral cutter head to become the broken magnesium or powdery crystals, the broken magnesium falls below the magnesium condenser 631, the broken magnesium falls into a crystallized magnesium storage chamber 646 by a crystallized magnesium locking upper valve 643 to be periodically opened, and the crystallized magnesium storage chamber 646 is communicated with the atmosphere by a crystallized magnesium locking lower valve 645. Before the lower locking valve 645 of the magnesium crystal is opened, it is necessary to ensure that the upper locking valve 643 of the magnesium crystal is in a tightly closed state, and inert gas, typically argon or nitrogen, is introduced into the storage chamber 646 of the magnesium crystal through the vacuum-breaking gas-filling pipe 662 so that the internal pressure of the storage chamber 646 of the magnesium crystal is balanced with the external atmospheric pressure, and then the lower locking valve 645 of the magnesium crystal is opened so that the pieces of magnesium stored in the storage chamber 646 of the magnesium crystal are dropped. If recycling is to be realized, directly collecting magnesium fragments and returning to the forefront aluminum-silicon-iron ternary alloy liquid mutual melting link. If the crystallized magnesium powder needs remelting for sale as commodity or further processing, the magnesium powder in the crystallized magnesium storage chamber 646 falls into the magnesium remelting furnace 653 through the opened crystallized magnesium locking down valve 645, is remelted into pure magnesium liquid 651 by heating, and is removed or directly pumped out of the ingot by a device such as a magnesium liquid injection dosing pump 652. After the crystalline magnesium storage chamber 646 is emptied, the locking crystalline magnesium locking lower valve 645 is closed in time, and the crystalline magnesium storage chamber 646 is vacuumized through the vacuum pumping pipeline 661 to reach the same vacuum degree as the magnesium condenser 631, so that the crystalline magnesium locking upper valve 643 is opened to receive a new batch of scraped crystalline magnesium powder.

In this embodiment, the composition of the final pure aluminum liquid 624 is formulated for use in accordance with 6061 aluminum alloy and other silicon-containing cast aluminum alloys.

Example 2:

the recovered mixed waste aluminum is melted to obtain 3.5% of iron, 7.6% of silicon and 2.3% of magnesium, and the components cannot be separated in advance by a mechanical method. The method adopts recovered waste magnesium to carry out mutual melting, centrifugal filtration for iron removal and distillation separation, thereby realizing the cooperative impurity removal and regeneration of aluminum and magnesium.

The waste magnesium is 10.1% of aluminum, 0.2% of iron and 0.5% of silicon, and is added according to 50% of the amount of the waste aluminum, and the waste magnesium is mutually melted in an induction furnace or a gas heating furnace to form aluminum-magnesium-silicon-iron quaternary alloy liquid, and then the aluminum-magnesium-silicon-iron quaternary alloy liquid enters a centrifugal rotary drum for separation.

Because of the small proportion of solid phase precipitates which can be formed, after the original aluminum silicon iron magnesium quaternary alloy liquid 330 is injected into the centrifugal drum 310, a certain amount of ferrosilicon filter residues 350 which are centrifugally filtered in the previous batches are added, and meanwhile, the cooling effect is realized.

After centrifugal filtration, most of iron in the original aluminum-silicon-iron-magnesium quaternary alloy liquid 330 enters into the ferrosilicon filter residue 350, and silicon is also greatly reduced. The distilled pure aluminum liquid 624 has iron content lower than 0.3 percent and silicon content about 2 percent, meets the component requirements of most cast aluminum alloys, and is recycled as the cast aluminum alloy by adding a certain alloy element.

Meanwhile, the condensed pure magnesium liquid 651 after distillation is purified, the aluminum content is less than 0.2%, and the method is suitable for preparing common magnesium alloy.

The waste aluminum and the waste magnesium realize impurity removal and regeneration, and the economic value and the application field are greatly improved compared with the prior art.

Example 3:

the magnesium distillation column 621 used in example 1 is heated externally and the evaporation and separation of magnesium is realized by internal vacuum, and the outer shell of the magnesium distillation column 621 is subjected to high temperature and high pressure, so that the diameter of the magnesium distillation column 621 cannot be too large, and is not more than 1 meter, so that the volume is smaller, and in addition, from the aspect of bearing pressure, a cylinder shape is adopted, so that possible other shapes are limited.

This example employs a magnesium distillation column 621 suitable for large scale, i.e., a double shell internal heat type distillation furnace. As shown in fig. 18 and 19. Fig. 18 shows the double-shell internal heat distillation furnace itself, and fig. 19 shows the whole connection relationship.

The housing 701 is made of a common steel plate, and may be a thickened or reinforced flat or curved steel plate with reinforcing ribs and reinforcing supports, or a cylindrical structure suitable for pressure resistance. The inner case 721 is made of a common steel plate, and is a rectangular solid surrounded by a common plane. Inside the inner shell 721 is a refractory and heat-insulating layer 720, which is made of a built heat-insulating material and a refractory material, and the refractory material of the innermost layer is aluminum-magnesium or graphite, so that the chemical reaction with the metal magnesium vapor does not occur in vacuum. The airtight gap between the outer shell 701 and the inner shell 721 is vacuumized to make the buffer pressure P2 of the double-shell distillation furnace interlayer consistent or close to the working vacuum pressure P1 of the double-shell distillation furnace inside the inner shell 721, and the vacuum degree in the interlayer is ensured by the interlayer vacuum pipeline 763. The heating means is disposed inside the refractory and heat insulating layer 720 by means of resistance heating or radiant heat pipe heating. The hot flue gas duct distillation tray 722 may be composed of a plurality of layers of stacked hot flue gas ducts closely arranged or welded rib plates, and fig. 18 and 19 show the type in which such heating pipes are closely combined with the distillation tray 722, or a resistance heating pipe for heat radiation, a hot flue gas duct are additionally independently arranged inside the refractory and heat-insulating layer 720, and heat transfer is performed to an almag liquid flowing on the hot flue gas duct distillation tray 722 by means of radiant heat, and the structure and function of the hot flue gas duct distillation tray 722 are the same as those of the distillation tray 622 in embodiment 1. In the embodiment, a gas radiation heat pipe is adopted for heating to save energy cost, the gas radiation heat pipe is a hollow heat-resistant steel or ceramic pipe, hot gas smoke flows in the gas radiation heat pipe, the temperature can reach 900-1100 ℃, heat is transferred to aluminum magnesium alloy liquid 613 to be evaporated by means of radiation, and a hot smoke inlet 702 and a smoke outlet 703 are arranged outside a shell 701.

The adoption of the double-shell internal heating type distillation furnace is equivalent to the realization of respective 'division' of the double-layer furnace shell: the outer shell 701 bears pressure, the inner shell 721 is heated, the heated inner furnace shell is not pressed, and the pressure-bearing outer shell 701 is not heated, so that the large-scale is easy to realize, for example, the area of the hot flue gas pipeline distillation column plate 722 can reach the evaporation area of 3X3 square meters or 5X5 square meters, if tens of layers of hot flue gas pipeline distillation column plates 722 exist, the total evaporation area can reach hundreds of square meters, the amount of evaporated magnesium per hour reaches more than several tons, and the large-scale is realized.

Example 4:

the solid ferrosilicon filter residue 350 obtained by centrifugal filtration has various use directions as a byproduct. If the magnesium in the magnesium alloy is not distilled and separated, the magnesium alloy can be used as a magnesium smelting reducing agent and a steel composite deoxidizing agent. The magnesium alloy is most preferably used as a reducing agent for magnesium smelting by a thermal method. The whole material realizes closed loop circulation.

The ferrosilicon filter residue 350 is transported to a thermal magnesium smelting workshop, mixed with dolomite calcined dolomite and then pressed into balls, enters a transverse tank or a vertical tank for smelting magnesium by a Pidgeon method, and is heated in vacuum, and unlike the common ferrosilicon, the decomposition of Mg2Si in a reducing agent at a high temperature in vacuum firstly occurs, and magnesium vapor is released to be condensed. Then the rest aluminum and silicon are subjected to reduction reaction with MgO in calcined dolomite in sequence, and slag forming reaction with CaO in calcined dolomite is carried out.

The utilization rate of the reducing agent, the calcined dolomite utilization rate, the reduction temperature and the vacuum degree, the service life of the reduction tank, the yield per unit time, the yield per unit equipment and the fuel gas energy consumption are all improved to a greater extent than those of the common #75 ferrosilicon, and the final capacities of the furnace burden and the reducing agent can be squeezed out by adopting high temperature and high vacuum because the crude magnesium is obtained without refining, so that the metal impurities silicon, aluminum, iron and calcium of the crystallized crude magnesium are improved, and the yield of the alloy is increased for the crude magnesium which is fused with the aluminum-silicon-iron ternary alloy liquid in the follow-up process. As for the calcium element therein, calcium which is more active in magnesium or aluminum is easily replaced with a desired metal element.

If the ferrosilicon filter residue 350 is required to be made into ferrosilicon or ferrosilicon strictly meeting the brand requirements, the ferrosilicon or ferrosilicon can be distilled and demagnetized in a closed electric arc furnace or induction furnace, then vacuum is broken to take out condensed magnesium, and then waste steel and ferrosilicon are added to adjust components until the ferrosilicon meets the brand requirements, or a thermit method is adopted, materials containing ferric oxide and silicon oxide are added to consume aluminum elements in the materials, reduced iron and silicon are alloyed, the alloy meeting the brand is obtained, and byproduct high-alumina slag is used as a raw material required by the refractory material industry and the like.

Claims

1. An apparatus for electroheat aluminum production, comprising:

a sealed submerged arc electric furnace, is used for smelting the aluminum-silicon resources or aluminum-containing solid wastes into the iron-aluminum alloy through a thermal reduction method, the iron-aluminum alloy is used for being melted with magnesium metal to form alloy liquid containing four elements of aluminum, magnesium, silicon and iron;

at least one aluminum-magnesium centrifugal separator (301), wherein the aluminum-magnesium centrifugal separator receives alloy liquid containing four elements of aluminum, magnesium, silicon and iron which are melted by iron-containing aluminum alloy and magnesium metal, the alloy liquid is separated into aluminum-magnesium alloy liquid and separated out solid-phase metal compounds after centrifugal treatment, and aluminum-magnesium alloy blocks are generated after the aluminum-magnesium alloy liquid is cooled;

at least one aluminum-magnesium continuous distillation and separation furnace, wherein the aluminum-magnesium continuous distillation and separation furnace receives aluminum-magnesium alloy blocks produced by an aluminum-magnesium centrifugal separator, remelts and distills the aluminum-magnesium alloy blocks and separates the aluminum-magnesium alloy blocks into aluminum liquid and magnesium vapor, and the magnesium vapor is condensed to generate condensed magnesium;

the aluminum-magnesium centrifugal separator (301) is provided with a space surrounded by a centrifugal fixed cylinder wall (302) and a centrifugal fixed cylinder protection cover plate (303), a detachable centrifugal cylinder (310) is arranged in the space, the centrifugal cylinder (310) comprises a centrifugal cylinder bottom plate (311), a centrifugal cylinder outer cylinder wall (312), a centrifugal cylinder inner cylinder wall (313) and a centrifugal cylinder top plate (314), the centrifugal cylinder outer cylinder wall (312) and the centrifugal cylinder inner cylinder wall (313) are arranged between the centrifugal cylinder bottom plate (311) and the centrifugal cylinder top plate (314) at the same circle center, an annular liquid receiving groove (318) of the centrifugal cylinder is arranged between the centrifugal cylinder outer cylinder wall (312) and the centrifugal cylinder inner cylinder wall (313), the inner space surrounded by the centrifugal cylinder inner cylinder wall (313) is a centrifugal cylinder inner cavity (317), a centrifugal cylinder liquid injecting channel (319) leading to the centrifugal cylinder inner cavity (317) is formed between the centrifugal fixed cylinder protection cover plate (303) and the centrifugal cylinder top plate (314), and a plurality of liquid throwing holes (320) are uniformly formed in the centrifugal cylinder inner cylinder wall (313).

2. An apparatus for electroheat aluminum production as claimed in claim 1, wherein: the aluminum-magnesium continuous distillation separation furnace comprises an aluminum-magnesium alloy remelting furnace (611), a magnesium distillation tower (621), an aluminum liquid heat preservation furnace (625), a magnesium condenser (631), a crystallized magnesium storage chamber (646) and a total vacuum pipeline and a vacuum pump (650); the aluminum magnesium alloy remelting furnace (611) is communicated with a top feed inlet of a magnesium distillation tower (621) through a vacuum liquid suction pipe, a bottom discharge outlet of the magnesium distillation tower (621) is communicated to an aluminum liquid heat preservation furnace (625) through an aluminum liquid concurrent pipe (623), the top of the magnesium distillation tower (621) is also communicated with a top feed inlet of a magnesium condenser (631) through a magnesium steam pipe (630), a bottom discharge outlet of the magnesium condenser (631) is communicated with a crystallized magnesium storage chamber (646), and the top of the magnesium condenser (631) is also communicated with a total vacuum pipeline and a vacuum pump (650).

3. An apparatus for electroheat aluminum production as claimed in claim 2, wherein: a plurality of layers of distillation trays (622) are vertically arranged in the inner cavity space of the magnesium distillation tower (621), an aluminum magnesium liquid connection area (802) is arranged on one side of the top of each distillation tray (622), an aluminum magnesium liquid falling hole (803) is formed in the other side of each distillation tray, a surrounding baffle (804) is arranged on the outer edge of the top of each distillation tray (622) in a surrounding mode, and a roundabout aluminum magnesium liquid flow channel (806) formed by a flow channel cofferdam (805) is arranged between each aluminum magnesium liquid connection area (802) and each aluminum magnesium liquid falling hole (803).

4. An apparatus for electroheat aluminum production as claimed in claim 2, wherein: the shell of the magnesium distillation tower (621) adopts a double-layer steel structure and comprises an outer shell (701) and an inner shell (702), an interlayer between the outer shell (701) and the inner shell (702) is subjected to vacuum treatment, and a fireproof heat insulation layer (720) is built on the inner wall of the inner shell (702).

5. An apparatus for electroheat aluminum production as claimed in claim 2, wherein: the magnesium condenser (631) is internally provided with a cooling cavity, the top of the cooling cavity is respectively communicated with a magnesium steam pipe (630) and a total vacuum pipeline and a vacuum pump (650), the bottom of the cooling cavity is communicated with a crystallized magnesium storage chamber (646), a cooling device is wrapped outside the cooling cavity, a spiral magnesium scraper (641) is arranged in the cooling cavity, the top of the cooling cavity is also provided with a magnesium steam baffle (642), and the magnesium steam baffle (642) is positioned between the cooling cavity and two connectors of the magnesium steam pipe (630) and the total vacuum pipeline and the vacuum pump (650).

6. An apparatus for electroheat aluminum production as claimed in claim 5, wherein: the cooling device comprises a negative pressure spray vaporization chamber (632), a vaporization negative pressure suction pipe and a vacuum pump (634), wherein the vaporization negative pressure suction pipe and the vacuum pump (634) are connected with the negative pressure spray vaporization chamber (632), and a plurality of atomizing water spray heads (633) are arranged in the negative pressure spray vaporization chamber (632).

7. An apparatus for electroheat aluminum production as claimed in claim 2 or 5, wherein: an upper crystallized magnesium locking valve (643) is arranged between the magnesium condenser (631) and the crystallized magnesium storage chamber (646), and a lower crystallized magnesium locking valve (645) is arranged at the discharge opening of the crystallized magnesium storage chamber (646).

8. An apparatus for electroheat aluminum production as claimed in claim 2, wherein: the crystallized magnesium storage chamber (646) is respectively communicated with a vacuum pumping pipeline (661) and a vacuum breaking inflation pipeline (662).

9. An apparatus for electroheat aluminum production as claimed in claim 2, wherein: the height of the aluminum liquid concurrent pipe (623) is calculated as the local atmospheric pressure divided by the standard atmospheric pressure multiplied by 4.5 m.