CN115896476A - Aluminum and aluminum alloy melt purification process - Google Patents
Aluminum and aluminum alloy melt purification process Download PDFInfo
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Abstract
The invention discloses a purification process of aluminum and aluminum alloy melts, and relates to the technical field of aluminum material smelting. The technology selects the advanced furnace bottom air brick material, and the inert gas continuously permeates into the furnace through the furnace bottom air brick to react with the hydrogen in the melt, thereby achieving the aim of removing the hydrogen; meanwhile, a part of hydrogen is brought out under the action of partial pressure difference in the floating process of the generated bubbles, and the bubbles collide or are removed from inclusion in the floating process and are brought out of the melt under the action of interfacial tension, so that purification is realized. The furnace bottom ventilation technology can realize continuous degassing and deslagging and also avoid secondary pollution to molten aluminum caused by refining in an artificial furnace.
Description
Technical Field
The invention relates to the technical field of aluminum material smelting, in particular to a process for purifying aluminum and aluminum alloy melt.
Background
The purification treatment of the aluminum alloy melt is one of the basic guarantee measures for producing high-quality aluminum castings and is also a main means for improving the comprehensive performance of the aluminum alloy. The refining effect of the aluminum alloy melt has important influence on the formation of looseness, air holes, inclusions and the like, and directly influences the physical property, the mechanical property and the service performance of the aluminum casting. Effective purification treatment of aluminum alloy melt is the first prerequisite for obtaining high-quality aluminum alloy components.
Since hydrogen is the only gas that is largely dissolved in the aluminum melt. Hydrogen is hardly soluble in solid aluminum, whereas it is very soluble in liquid aluminum and increases with increasing temperature. The solubility of hydrogen above and below the solidus is 0.65mL and 0.034mL per 100g of aluminum liquid, i.e., the solubility difference of hydrogen in the solid and liquid phases is about 19.1 times, while the normal hydrogen content per 100g of aluminum alloy melt is about 0.10-0.40 mL. Therefore, the degassing and purifying of the aluminum alloy melt is mainly used for removing hydrogen, and the main problems are that the hydrogen content of the aluminum alloy is high, and the degassing and purifying technology of the aluminum alloy melt cannot meet the production requirements of high-quality alloys. Generally, 0.1 to 0.2mL of hydrogen per one liter of 00g of aluminum is required, whereas the hydrogen content per 100g of aluminum alloy for aircraft parts is required to be not more than 0.06mL.
Hydrogen is mainly present in the aluminum alloy melt in the following forms: the atomic state, namely H is dissolved in the aluminum melt; molecular state, H is H 2 Exist in A1 2 0 3 Hydrogen bubbles with negative radius of curvature are formed: in the compound state, hydrogen atoms and certain elements in the aluminum liquid form hydrides. In which only hydrogen molecules are likely to form pores. Due to the difference in solubility, hydrogen tends to escape from the melt, forming bubbles when the hydrogen pressure is greater than the surface tension and hydrostatic pressure, thereby creating pores in the casting or ingot. Many years of research and practice have confirmed that: the main source of hydrogen in the aluminum alloy melt is the reaction of aluminum liquid and water vapor. Above 400 ℃, the following reaction occurs after contacting the aluminum with water vapor in air:
3H 2 o (steam) ten 2AI (liquid) = Al 2 O 3 +3H 2
3H 2 O (steam) ten 2AI (liquid) = Al 2 O 3 +6{H}
A part of hydrogen is generated and a part of hydrogen molecules are generated, wherein the former is absorbed by the aluminum liquid, and the latter enters the air. The higher the melting temperature is, the more easily the aluminum liquid and the water vapor react, and the greater the harm is. In order to control the harmful reaction of the aluminum liquid and the water vapor, the furnace burden and the smelting tool need to be preheated after surface cleaning, and the water vapor adsorbed on the surface is removed so as to enter the aluminum liquid. Before various solvents are used, the solvents must be dried or dehydrated and premelted, and the furnace lining must be dried. However, practical experience proves that even if the process operation is strictly followed, the reaction of the aluminum liquid and the water vapor cannot be completely avoided, so that a certain amount of hydrogen is always contained in the aluminum liquid.
Inclusions generally refer to any solid or liquid phase exogenous impurities present above the liquidus temperature. The common non-metal inclusions in the aluminum alloy melt comprise oxides, carbides, nitrides, borides and the like, most of the inclusions exist in a granular or film shape, and the typical grain size is in a range of l-30 um. Except from the charge, is mainly formed by the reaction of aluminum with oxygen during melt casting. The thickness of the oxide film on the surface of the aluminum is about 2-10 nm, and is increased to 200nm when the thickness is close to the melting point, so that the oxide film on the liquid surface is thicker and the structure is changed: one side of the aluminum liquid is compact, so that the aluminum liquid can be protected; the outer side is loose, the inner side is provided with small holes with the diameter of 5-10 nm, and the small holes are filled with hydrogen, air and water vapor, if a liquid film is stirred into the aluminum liquid, the aluminum liquid increases slag and gas. In addition, some undesirable primary intermetallic compounds, such as A1, may also be present in the aluminum alloy melt 3 Zr，A1 3 Ti, etc., fe-containing aluminum alloys may form various Fe-rich intermetallic compounds. It is worth noting that: the gas and the inclusion in the aluminum alloy melt have strong interaction, the hydrogen content in the aluminum liquid is greatly influenced by the inclusion content, and when the inclusion content w is 0.002 percent and 0.02 percent, the corresponding contentThe hydrogen contents of (A) were 0.2mL/100g-Al and 0.35mL/l00g-Al, respectively. Under the condition of the same hydrogen content, the higher the inclusion content is, the higher the porosity is. On the contrary, when the inclusion amount in the aluminum liquid is very low, the hydrogen content is low, even if the hydrogen is artificially introduced into the aluminum liquid, the hydrogen can be automatically removed, and the original content can be quickly recovered. Even if a small amount of inclusions exist, the critical concentration value for forming pores can be significantly reduced. Therefore, deslagging and hydrogen removal should be performed simultaneously, and it is also important that the effects of hydrogen removal and inclusion removal are always combined, but each is emphasized, regardless of the refining process.
At present, the comprehensive treatment of purification and homogenization of aluminum alloy melt is considered to be a common technical basic problem which must be solved for obtaining high-quality aluminum alloy. There are many studies related to, for example, various purification methods (physical and chemical) for degassing and deslagging aluminum melts, various methods for treating the melts by electric and magnetic fields, studies on the influence of the structure of alloy melts and the thermodynamics of the melts on solidification structures, studies on rapidly solidified/powder metallurgy aluminum alloys, and the like. The refining effect in the conventional process for refining the aluminum alloy is better by applying C1 2 Gas and salts, their by-products A1C1 3 HCl and C1 2 Qi causes serious damage to human body, environment and facilities. But non-toxic and non-polluting refining processes, e.g. with N 2 ，Ar 2 The inert gas refining agent often cannot reach C with serious environmental pollution 2 C1 6 The effect achieved by the refining treatment. The refining agent developed in recent years is not only poor in effect but also contains carbonate and nitrate as basic components and a small amount of C 2 C1 6 Therefore, the emission contains a large amount of greenhouse gas C0 2 Nitrogen oxides. In addition, in order to improve the mechanical properties of the aluminum alloy, al-Ti and Al-Ti-B alloys are commonly used as grain refiners to realize grain refinement. But the preparation of Al-Ti and Al-Ti-B alloys also causes environmental pollution.
Disclosure of Invention
The invention provides a process for purifying aluminum and aluminum alloy melts, which solves the problems of hydrogen removal and refining in the aluminum and aluminum alloy smelting process.
In order to solve the above problems, the present invention provides the following technical solutions:
the process for purifying the melt of aluminum and aluminum alloy comprises a step of treating in a smelting furnace and a step of treating the melt after smelting, wherein the step of treating the melt after smelting comprises the step of blowing inert gas in the melt in a rotating way, and hydrogen is brought out in the process that the inert gas escapes from the melt.
Preferably, the inert gas is argon, the blowing pressure of the argon is kept between 0.2 and 0.6MPa, and the argon is blown into the melt from the bottom end of a rotating rod in the autorotation process through the hollow rotating rod extending into the melt.
Preferably, the distance from the bottom end of the hollow rotating rod to the bottom of the chamber is 20-50 cm, and the introduced volume of the argon is 400-500 times of the volume of the hydrogen in the melt.
Preferably, the step of processing the melt after smelting further comprises double-stage filtration treatment, in particular to continuously passing the melt after the argon injection treatment through 30-mesh and 50-mesh ceramic filter plates.
Preferably, the smelting furnace inner treatment step comprises:
(1) Adding an alkali removing agent into the aluminum or aluminum alloy melt in a smelting furnace, wherein the adding amount of the alkali removing agent is 1kg/t.Al;
(2) And laying air bricks at the bottom of the smelting furnace, and introducing nitrogen into the smelting furnace through the air bricks.
Preferably, the alkali remover consists of the following components in parts by weight: KC 1-25 parts, naCl 35-40 parts, na 2 AlF 4 15 to 20 portions of SiF 2 4 to 8 portions of NaCO 3 1 to 5 portions of NaSO 4 1-3 parts.
The invention has the advantages that:
the invention adopts a refining combined process of refining adsorption of an alkali remover and introducing high-purity nitrogen into the furnace bottom air brick in the furnace to remove slag and degas alkali elements in the smelting furnace, and adopts a degassing and deslagging process matched with a 30ppi +50ppi double-stage filtration process outside the furnace by adopting a rotary blowing degassing process. The furnace bottom air brick degassing and deslagging process achieves the domestic advanced process, the process selects the advanced furnace bottom air brick material, and inert gas continuously permeates into the furnace through the furnace bottom air brick to react with hydrogen in a melt so as to achieve the aim of removing the hydrogen; meanwhile, a part of hydrogen is brought out under the action of partial pressure difference in the floating process of the generated bubbles, and the bubbles collide or are removed from inclusion in the floating process and are brought out of the melt under the action of interfacial tension, so that purification is realized. The furnace bottom ventilation technology can realize continuous degassing and deslagging and also avoid secondary pollution to molten aluminum caused by refining in an artificial furnace.
The invention effectively solves the problem of slag content of the aluminum alloy melt with complex components, so that the slag content in the aluminum liquid is less than 0.5mm 2 kg-Al; meanwhile, the problem of hydrogen content in the melt is solved, so that the hydrogen content control amount is 0.08mL/100g-Al.
Drawings
In order to more clearly explain the technical solution of the present application, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious to those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic top view and a schematic physical drawing of a rotary blowing purification apparatus;
FIG. 2 is a physical diagram of a hollow rotating rod;
FIG. 3 is a schematic view of the arrangement of the air brick;
FIG. 4 is a pictorial view of a dual stage filtration device;
FIG. 5 shows the measured values of hydrogen content before and after dehydrogenation treatment of an aluminum alloy melt; wherein, the left graph is the hydrogen content detection value before dehydrogenation, and the right graph is the hydrogen content detection value after dehydrogenation.
FIG. 6 is a graph of a process for removing hydrogen by a rotary blowing degassing 6061;
FIG. 7 shows the effect of removing slag while degassing by rotary blowing;
FIG. 8 is a 6061 aluminum alloy slag inclusion analysis report;
FIG. 9 is a line graph showing Na content of the primary aluminum liquid before alkali removal;
FIG. 10 is an elemental analysis report of a finished aluminum alloy product after alkali removal.
Detailed Description
In order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further described with the specific embodiments.
Example 1: the aluminum alloy melt was purified as follows:
(1) The method comprises the following steps of putting 6061 aluminum alloy into a smelting furnace, heating and melting at 740 ℃ to form a melt, adding an alkali remover into the aluminum or aluminum alloy melt, wherein the adding amount of the alkali remover is 1kg/t.Al, and the alkali remover comprises the following components in parts by weight: KC1 part, naCl 35 parts, na 2 AlF 4 15 parts of SiF 2 4 parts of NaCO 3 1 part of NaSO 4 1 part. Paving air bricks at the bottom of the smelting furnace, and introducing nitrogen into the smelting furnace through the air bricks (as shown in figure 3);
(2) After smelting, transferring an aluminum alloy melt into a degassing chamber of a rotary blowing purification device from a smelting furnace, heating and preserving heat, inserting hollow rotating rods (shown in figure 2) with the length of 1240-1260mm into the melt until the distance from the bottom ends of the hollow rotating rods to the bottom of a chamber of the degassing chamber is 20-50 cm, connecting the upper ends of the hollow rotating rods with an output shaft of a motor, wherein the lower ends of the hollow rotating rods are disc-shaped, a plurality of gas outlet channels are radially arranged in the disc, the gas outlet channels are all communicated with a hollow inner cavity of the hollow rotating rods, the gas outlet channels are opened from the outer edge of the disc, and argon is sprayed into the melt from the outer edge of the disc through the hollow inner cavity and the gas outlet channels. When argon is introduced, the hollow rotating rod rotates under the driving of a motor, the rotating speed is 450rpm, and the argon is sprayed into the melt from the outer edge of a bottom disc of the rotating rod in the rotating process through the hollow rotating rod extending into the melt (as shown in figure 1). The volume of the introduced argon is 400 times of the volume of the hydrogen in the melt, and the blowing pressure of the argon is kept at 0.2MPa.
The inlet and outlet of the degassing device adopt a subsurface flow design, and inert gas is added to inhibit the oxidation of the surface of the aluminum solution. The heating is performed by using a silicon nitride heater protective sleeve. The flow of the melt in figure 1 maximizes the residence time of the bubbles in the aluminum melt.
(3) Double-stage filtration treatment: and injecting the degassed melt into a double-stage filtering device, wherein the melt subjected to argon blowing treatment continuously passes through 30-mesh and 50-mesh ceramic filter plates. As shown in figure 4, the right side groove is provided with a 30-mesh filter plate, and the melt flows into the left 50-mesh filter plate after being filtered by the right side groove to be continuously filtered, so that double-stage filtration is completed.
The rotary blowing degassing and purifying method is one of bubble floating method, and is characterized by that the inert gas or active gas insoluble in aluminium alloy melt is introduced into the aluminium alloy melt, and when it flows through the rotating nozzle blade, it is broken and jetted out at high speed to produce lots of external bubbles. Because the partial pressure of hydrogen in the bubbles is zero, the hydrogen dissolved in the aluminum alloy melt continuously enters the bubbles according to the principle of hydrogen removal dynamics, and the hydrogen in the bubbles is not balanced until the partial pressure of the hydrogen in the bubbles is increased to meet a certain relation with the concentration of the hydrogen in the aluminum alloy melt. After the bubbles float out of the liquid surface, hydrogen in the bubbles also enters the atmosphere. Meanwhile, the bubbles also have the function of adsorbing oxide inclusions in the aluminum alloy melt, and also carry away hydrogen adsorbed on the oxide inclusions.
In the process of degassing and purifying the aluminum alloy melt by rotary blowing, the rotary spray head rotates at a high speed, and in the rotating process of the spray head, fluid sprayed by the spray head blades generates strong turbulence. The air bubble sprayed from the high-speed rotating sprayer is captured by the liquid sprayed by the sprayer blade and the liquid with relatively low peripheral speed at the position close to the sprayer, and the air bubble is cut off from the liquid under the action of turbulent shear stress generated by the two layers of fluid when the force borne by the air bubble is larger than the force borne by the air bubble, so that the air bubble is split into two air bubbles. The split bubble is then captured by the other tangential liquid layers and can continue to split into smaller bubbles until the shear stress between the two layers of fluid is insufficient to break the bubble or the bubble out of the range of action of the shear stress. Thereby can produce than single tube or multitube more tiny, more even bubble, effectively increase specific surface area, also effectively increase mass transfer diffusion capacity, prolonged gas-liquid interface's contact action time simultaneously, at the purge gas inlet flow for wherein the concentration of hydrogen is bigger when purifying bubble effusion aluminum alloy melt, effectively utilized the purge gas, thereby can obtain splendid purifying effect.
a. Thermodynamic analysis
When the external purifying bubbles enter the aluminum alloy melt, the partial pressure of hydrogen in the aluminum alloy melt is low because the aluminum alloy melt does not contain hydrogenP H2 =0, so that the chemical potential of hydrogen therein is
u H2 ＝u 0 H2 +RTln(P H2 /P 0 H2 )＝-∞
Because the effect of hydrogen atoms dissolved in the aluminum alloy melt on the aluminum alloy melt is very small, the aluminum alloy melt is assumed to be an ideal solution, and the concentration of hydrogen in the aluminum alloy melt is set to be C H2 The chemical potential of hydrogen therein
u H ＝u 0 H2 +RTlnC H2 Constant number
The two formulas are shown as follows: u. of H >u H2 That is, the chemical potential of hydrogen in the aluminum alloy melt is higher than that in the purified gas, so that the hydrogen dissolved in the aluminum alloy melt diffuses into the purified gas bubbles. Of course, after a certain hydrogen partial pressure exists in the purge gas bubbles, hydrogen in the purge gas bubbles also diffuses into the aluminum alloy melt, and the amount of hydrogen in the aluminum alloy melt diffusing into the purge gas bubbles is larger than the amount of hydrogen diffusing into the aluminum alloy melt from the purge gas bubbles because the chemical potential in the aluminum alloy melt is still higher than the chemical potential of hydrogen in the purge gas bubbles. This process is continued until the chemical potentials of the hydrogen are equal between the two, and the hydrogen reaches a dynamic equilibrium in the two in response to an equal mutual diffusion.
The minimum volume of purge gas required when a specified degree of outgassing is achieved. If the inert gas is constant, the degree of outgassing may also be calculated. In practical situations, the purification bubbles float faster and escape without reaching the equilibrium state, and therefore the amount of inert gas required is greater than the calculated equilibrium value. Moreover, when the degassing is carried out to a certain extent, the amount of hydrogen dissolved in the aluminum alloy melt is gradually reduced, so that the efficiency of hydrogen removal by argon or other inert gases is remarkably reduced. For example, to achieve a dehydrogenation level of 0.06ml/l00g-Al, the degassing volume ratio must be as high as 400Ar/H 2 Therefore, the amount of inert gas required is greater than the calculated equilibrium value.
b. Kinetic analysis
According to the result of thermodynamic analysis, only the limit and direction of the dissolution process of hydrogen in the aluminum liquid can be determined, so that the kinetic process of hydrogen removal of the aluminum alloy melt must be analyzed to know the speed and the final result of hydrogen removal, and the hydrogen removal effect can be better tested. The hydrogen removing process of the aluminum alloy melt is a dynamic process of degassing and air suction, and consists of a hydrogen removing process in the aluminum alloy melt and an oxidation hydrogen absorption process on the surface of the aluminum alloy melt. The effect of hydrogen removal is determined by the dynamic equilibrium of these two processes in opposite directions. The efficiency of the aluminum alloy melt dehydrogenation purification depends greatly on the mass transfer diffusion coefficient of the aluminum alloy melt and the atmosphere as well as the aluminum alloy melt and the purification bubbles, and simultaneously, the efficiency of the removal of impurities also depends greatly on the collision between the aluminum alloy melt and the atmosphere, the adsorption of the purification bubbles to the impurities, the size and the distribution of the purification bubbles and the like. In summary, the kinetic conditions inside the aluminum alloy melt have a great influence on the purification efficiency.
The degassing process can be divided into two cases: one is a dehydrogenation process capable of forming hydrogen bubbles; the other is a dehydrogenation process that does not form hydrogen bubbles. For the dehydrogenation process capable of forming hydrogen bubbles, three stages can be roughly divided: first, nucleation of bubbles; then the bubbles grow and float; and finally the escape of bubbles. In an aluminum alloy melt, the nucleation of bubbles must satisfy the following two conditions: 1) Hydrogen dissolved in the aluminum alloy melt is in a supersaturated state and has a precipitation pressure; 2) The pressure of the gas in the bubbles is greater than the external pressure acting on the bubbles; the dehydrogenation process incapable of forming hydrogen bubbles mainly means dehydrogenation by forming other kinds of bubbles, such as rotary blowing of nitrogen gas or argon gas. The kinetics of hydrogen removal from the initial hydrogen-free bubble migration of hydrogen in the aluminum alloy melt can be broken down into the following five steps
I. Through convection and diffusion, hydrogen in the aluminum alloy melt is transferred to a gas-liquid interface of the aluminum liquid and bubbles;
II, converting hydrogen atoms from a dissolved state to an adsorbed state;
III, mutually interacting hydrogen atoms adsorbed on a gas-liquid interface to combine the hydrogen atoms into hydrogen molecules;
desorption of hydrogen molecules from the gas-liquid interface;
v. hydrogen molecules diffuse into gas phase and escape from the aluminum liquid along with the upward floating of bubbles.
In the first stage, mainly step I, gas atoms migrate from the inside of the aluminum alloy melt to the surface of the aluminum alloy melt or to the surface of the bubbles. In the floating process of the inert gas, the inert gas and the aluminum alloy melt generate relative motion. The second stage mainly comprises a step II, a step III and a step IV, wherein gas atoms are converted into an adsorption state from a dissolution state, and react in an adsorption layer to generate gas molecules to be desorbed from the surface. In the third stage, gas molecules diffuse into the gas space or bubble and proceed quickly, and are not considered as a control link.
Therefore, the process of rotary blowing degassing and purifying the aluminum alloy melt should be considered integrally, and technological parameters such as proper air inlet flow and rotation speed, proper degassing time, proper resting time, degassing temperature and the like are selected according to actual conditions, so that the purification process is improved, and the purification effect is improved.
c. Simulation model selection analysis of alloy melt rotation blowing degassing purification process
When the rotor system works, the rotor system is subjected to the coupling action of structural centrifugal force, vibration stress and the like, and the establishment of the coupling function has a great relation with the rotating speed of the system. When the rotor is operating, the critical speed must be taken into account when seeking a range of speed variation. Generally, at each stage of the critical rotation speed, the amplitude of the rotor reaches the maximum, and with the occurrence of resonance, the rotor operates in an extremely unstable state, and once the rotor operates at the critical rotation speed for a long time, the system is likely to be damaged, thereby causing an accident. The rotary blowing component of the aluminum alloy melt rotary blowing degassing and purifying equipment can be basically equivalent to a simple rotor system that a straight rod supported by two rolling bearings is connected with a ventilating disc. In a rotor system, one of the main reasons for influencing the critical speed is the system support, and therefore, it is necessary to properly design and arrange the positions of the rolling bearings. Generally, the flexible rotor system works stably between the first and second critical rotating speeds due to the negative feedback effect of the Coriolis force and the gyro effect. Therefore, the rotational speed is generally designed to be greater than the first-order critical rotational speed and less than the second-order critical rotational speed.
Modal analysis can determine the natural frequency and mode shape of a structure, and the natural frequency and mode shape are just important parameters in the design of a structure bearing dynamic load. When the system vibration is transferred, the most harmful vibration is low-frequency high-amplitude vibration, and the research of high-frequency vibration is generally complex and has little harm, so the natural frequency of the first ten orders is only considered in the selection application.
The shape of the rotating rod in the vibration process is differentiated, and parameters are applied to representing vibration I & ltme & gt distribution, frequency distribution, displacement, speed, acceleration and the like of vibration points during numerical calculation. The calculation is that ANSYS modal vibration analysis is adopted, material performance parameters, geometric parameters and load distribution of the rotating rod are used as basic distribution variables, finite element numerical simulation of the vibration problem is realized by using a parameterized design language APDL, and amplitude, vibration mode, vibration stress strain and the like under various orders of frequency are obtained. Because the vibration parameters are influenced mainly by the material performance, the geometric parameters and the supporting mode of the vibrating body, the rotating rod is considered to work in a design allowable range as long as the maximum amplitude is in a required range in the numerical simulation process, namely the rotating rod is reasonable in material selection, the geometric shape meets the requirement and the supporting mode is reasonable in design.
Through comparative screening, the length of a rotor with the length of 1240-1260mm is finally selected, the rotor is made of boron nitride materials, and a double-rotor double-chamber design is adopted for a degassing chamber (shown in figure 1). The effect of the aluminum alloy melt rotary blowing degassing purification treatment is shown in fig. 5-10.
Example 2: the rest is the same as example 1 except that: the alkali remover comprises the following components in parts by weight: KC1 25 parts, naCl 40 parts, na 2 AlF 4 20 parts of SiF 2 8 parts of NaCO 3 5 parts of NaSO 4 And 3 parts.
The volume of the introduced argon is 500 times of the volume of the hydrogen in the melt, and the blowing pressure of the argon is kept at 0.6MPa.
In order to accurately reflect the hydrogen content in the aluminum alloy melt in the production process, a British HYCAL hydrogen tester is used for measuring the hydrogen content in the melt, and the hydrogen content in the aluminum alloy melt treated in the example 1 is shown in FIG. 5.
The present application has been described in detail with reference to specific embodiments and illustrative examples, but the description is not intended to limit the application. Those skilled in the art will appreciate that various equivalent substitutions, modifications or improvements may be made to the presently disclosed embodiments and implementations thereof without departing from the spirit and scope of the present disclosure, and these fall within the scope of the present disclosure. The protection scope of this application is subject to the appended claims.
Claims (6)
1. The process for purifying the aluminum and aluminum alloy melt is characterized by comprising a step of treating the aluminum and aluminum alloy melt in a smelting furnace and a step of treating the melt after smelting, wherein the step of treating the melt after smelting comprises the step of blowing inert gas into the melt in a rotating mode, and hydrogen is brought out in the process that the inert gas escapes from the melt.
2. The process of claim 1, wherein the inert gas is argon, the argon is injected under a pressure of 0.2 to 0.6Mpa, and the argon is injected into the melt from the bottom end of a hollow rotating rod extending into the melt during spinning.
3. The process of claim 2, wherein the distance from the bottom end of the hollow rotating rod to the bottom of the chamber is 20-50 cm, and the volume of the introduced argon gas is 400-500 times of the volume of the hydrogen gas in the melt.
4. The process of claim 3, wherein the step of treating the molten aluminum and aluminum alloy further comprises a double-stage filtration treatment, in which the molten aluminum and aluminum alloy after the step of treating the molten aluminum and aluminum alloy by argon blowing is continuously passed through 30-mesh and 50-mesh ceramic filter plates.
5. The process for cleaning aluminum and aluminum alloy melts according to any one of claims 1 to 4, wherein the step of treating in the smelting furnace comprises:
(1) Adding an alkali removing agent into the aluminum or aluminum alloy melt in a smelting furnace, wherein the adding amount of the alkali removing agent is 1kg/t.Al;
(2) And laying air bricks at the bottom of the smelting furnace, and introducing nitrogen into the smelting furnace through the air bricks.
6. The process for purifying aluminum and aluminum alloy melts as recited in claim 5, wherein the alkali removal agent comprises the following components in parts by weight: KC 1-25 parts, naCl 35-40 parts, na 2 AlF 4 15 to 20 portions of SiF 2 4 to 8 portions of NaCO 3 1 to 5 portions of NaSO 4 1-3 parts.
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