1. The composite aluminum alloy refining agent is characterized by comprising a first refining agent, a second refining agent and a third refining agent; wherein the content of the first and second substances,

the first refining agent comprises the following components in percentage by mass:

sodium nitrate: 34 percent; graphite powder: 6 percent; cryolite powder: 20 percent; industrial salt: 10 percent; grain refiner: 30 percent;

the second refining agent comprises the following components in percentage by mass:

zinc chloride: 20 percent; graphite powder: 6 percent; hexachloroethane: 4 percent; cryolite powder: 20 percent; CaF₂: 20 percent; industrial salt: 10 percent; grain refiner: 20 percent;

the third refining agent comprises the following components in percentage by mass:

sodium nitrate: 36 percent; graphite powder: 6 percent; industrial salt: 28%; grain refiner: 30 percent; wherein the content of the first and second substances,

the grain refiner is obtained by mixing, grinding and sintering aluminum strontium slag and aluminum alloy mother phase powder in a mass ratio of 1: 1.

2. The composite aluminum alloy refining agent according to claim 1,

the sintering parameters are as follows: the sintering pressure is 9-50 MPa, the sintering temperature is 450-550 ℃, and the sintering time is 10-20 min.

3. The composite aluminum alloy refining agent according to claim 1,

the aluminum alloy mother phase powder comprises the following elements in percentage by mass: 10% -12%, Mn: 0.2-0.4%, Mg: 0.22 to 0.30 percent of Fe, less than or equal to 0.95 percent of Fe, less than or equal to 1.0 to 2.0 percent of Cu, less than or equal to 1.0 percent of Zn, less than or equal to 0.15 percent of Ti and Zr, less than or equal to 0.01 percent of Sn, less than or equal to 0.01 percent of Pb, and the balance of Al, wherein the total is 100 percent.

4. A method of refining an aluminum alloy, the method comprising the steps of:

degassing by adding a composite aluminium alloy refining agent as defined in any one of claims 1 to 3:

feeding a first refining agent into the aluminum liquid according to the proportion of 3-4 kg/ton of aluminum liquid, uniformly stirring and degassing for the first time;

feeding the second refining agent into the aluminum liquid according to the proportion of 3-4 kg/ton of aluminum liquid, uniformly stirring and degassing for the second time;

and feeding the third refining agent into the aluminum liquid according to the proportion of 3-4 kg/ton of aluminum liquid, uniformly stirring and degassing for the third time.

5. The aluminum alloy refining method according to claim 4,

each degassing mode adopts 90% nitrogen and 10% CO₂Blowing the aluminum liquid from the furnace bottom.

6. The aluminum alloy refining method according to claim 5,

the blowing time is 15-20 min each time.

7. The aluminum alloy refining method according to claim 4,

and the temperature of the aluminum liquid is kept between 710 and 740 ℃ in the blowing process.

8. The aluminum alloy refining method according to claim 4,

the aluminum liquid is obtained by smelting an aluminum alloy raw material; wherein, the aluminum alloy raw material comprises the following elements in percentage by mass: 10% -12%, Mn: 0.2-0.4%, Mg: 0.22 to 0.30 percent of Fe, less than or equal to 0.95 percent of Cu, less than or equal to 1.0 to 2.0 percent of Cu, less than or equal to 1.0 percent of Zn, less than or equal to 0.15 percent of Ti and Zr, less than or equal to 0.01 percent of Sn, less than or equal to 0.01 percent of Pb, and the balance of Al.

9. The aluminum alloy refining method according to claim 8,

the smelting process comprises smelting, stirring, slag skimming, sampling and testing, standing and heat preservation, refining, stirring, slag skimming and online refining.

10. An aluminum alloy refining method according to claim 4, characterized in that the method further comprises the steps of:

filtering impurities in the aluminum liquid from the degassed aluminum liquid;

and casting the aluminum liquid with impurities removed into aluminum alloy ingots.

Background

At present, aluminum is the metal with the largest amount except steel in the world at present. In the colored whole genus, aluminum is the front group in terms of reserves, yields and dosages.

The waste aluminum is an important resource, and the recovery, regeneration and utilization of the waste aluminum are well done, so that the waste aluminum is beneficial to the effective utilization of the resource, the environmental protection, the energy conservation and the like. The regeneration and utilization of the waste aluminum are great social and economic benefits, and have important practical significance for the sustainable and stable development of economy.

The recovery and the regeneration of the waste aluminum not only lead the resource to be recycled, but also greatly reduce the greenhouse gas CO₂And (4) discharging, because the energy consumption of the secondary aluminum is only 3.5-5.5% of that of the primary aluminum production. With the development of the aluminum industry, the secondary aluminum industry will be better developed. How to change the waste aluminum into a high value-added product with the lowest production cost is the key point of impurity removal technology in the processes of pretreatment, smelting and refining of the waste aluminum.

During the melting of aluminum and aluminum alloys, hydrogen and oxide inclusions are the main species contaminating the aluminum melt. And the main defects in cast aluminum alloys: porosity and slag inclusions are caused by gas and solid particles such as oxides remaining in the alloy. Therefore, not only is it important to select a proper and rational melting process, but also a refining and purifying treatment of the melt is important to obtain a high quality melt.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a composite aluminum alloy refining agent which is used in the aluminum alloy refining process, not only can not generate the problem that the mechanical property of an aluminum alloy casting is influenced because crystal grains grow up due to high temperature or excessively low temperature, but also has good compatibility, can reduce the use of the refining agent, reduces the production cost and also improves the production efficiency.

In order to solve the technical problems, the technical scheme of the invention is as follows: a composite aluminum alloy refining agent comprises a first refining agent, a second refining agent and a third refining agent; wherein the content of the first and second substances,

the first refining agent comprises the following components in percentage by mass:

sodium nitrate: 34 percent; graphite powder: 6 percent; cryolite powder: 20 percent; industrial salt: 10 percent; grain refiner: 30 percent; the second refining agent comprises the following components in percentage by mass:

zinc chloride: 20 percent; graphite powder: 6 percent; hexachloroethane: 4 percent; cryolite powder: 20 percent; CaF₂: 20 percent; industrial salt: 10 percent; grain refiner: 20 percent;

the third refining agent comprises the following components in percentage by mass:

sodium nitrate: 36 percent; graphite powder: 6 percent; industrial salt: 28%; grain refiner: 30 percent; wherein the content of the first and second substances,

the grain refiner is obtained by mixing, grinding and sintering aluminum strontium slag and aluminum alloy mother phase powder in a mass ratio of 1: 1.

Further, the sintering parameters are as follows: the sintering pressure is 9-50 MPa, the sintering temperature is 450-550 ℃, and the sintering time is 10-20 min.

Further, the aluminum alloy mother phase powder comprises the following elements in percentage by mass: 10% -12%, Mn: 0.2-0.4%, Mg: 0.22 to 0.30 percent of Fe, less than or equal to 0.95 percent of Fe, less than or equal to 1.0 to 2.0 percent of Cu, less than or equal to 1.0 percent of Zn, less than or equal to 0.15 percent of Ti and Zr, less than or equal to 0.01 percent of Sn, less than or equal to 0.01 percent of Pb, and the balance of Al, wherein the total is 100 percent.

The invention also provides an aluminum alloy refining method, which comprises the following steps:

adding a composite aluminum alloy refining agent for degassing:

feeding a first refining agent into the aluminum liquid according to the proportion of 3-4 kg/ton of aluminum liquid, uniformly stirring and degassing for the first time;

feeding the second refining agent into the aluminum liquid according to the proportion of 3-4 kg/ton of aluminum liquid, uniformly stirring and degassing for the second time;

and feeding the third refining agent into the aluminum liquid according to the proportion of 3-4 kg/ton of aluminum liquid, uniformly stirring and degassing for the third time.

Further, each degassing method adopts 90% nitrogenGas and 10% CO₂Blowing the aluminum liquid from the furnace bottom.

Furthermore, the air blowing time is 15-20 min each time.

Further, the temperature of the aluminum liquid is kept between 710 and 740 ℃ in the blowing process.

Further, the aluminum liquid is obtained by smelting an aluminum alloy raw material; wherein, the aluminum alloy raw material comprises the following elements in percentage by mass: 10% -12%, Mn: 0.2-0.4%, Mg: 0.22 to 0.30 percent of Fe, less than or equal to 0.95 percent of Cu, less than or equal to 1.0 to 2.0 percent of Cu, less than or equal to 1.0 percent of Zn, less than or equal to 0.15 percent of Ti and Zr, less than or equal to 0.01 percent of Sn, less than or equal to 0.01 percent of Pb, and the balance of Al.

Further, the smelting process comprises smelting, stirring, slag skimming, sampling and assay, standing and heat preservation, refining, stirring, slag skimming and online refining.

Further, the method comprises the following steps:

filtering impurities in the aluminum liquid from the degassed aluminum liquid;

and casting the aluminum liquid with impurities removed into aluminum alloy ingots.

After the technical scheme is adopted, the invention has the following beneficial effects:

1. the aluminum alloy ingot prepared by the aluminum alloy refining method of the composite aluminum alloy refining agent is used for replacing the conventional common refining agent, the smelted aluminum liquid is smelted and refined, and then the high-quality aluminum alloy ingot is prepared, the grain size of the aluminum alloy in the aluminum alloy ingot can be greatly reduced, the grain size of the aluminum alloy can be reduced to 20-80 mu m, other eutectic grains can be reduced to about 15 mu m, and the problem that the mechanical property of the aluminum alloy casting is influenced due to the fact that the grains grow up due to high temperature or too low temperature can not be caused in the die casting process of the aluminum alloy ingot prepared by the aluminum alloy ingot;

2. the aluminum alloy refining method using the composite aluminum alloy refining agent has the advantages that the first refining agent is used for blowing for the first time, the second refining agent is used for the second time, the third refining agent is used for the third time, the blowing time is 15-20 min, the mixture is used as the refining agent, the body material is used as the main component of the refining agent, the compatibility is good in the aluminum liquid refining and degassing process, the use of the refining agent can be reduced, the production cost is reduced, and the production efficiency is also improved.

Drawings

FIG. 1 is a process flow diagram of the aluminum alloy refining method of the present invention.

Detailed Description

The invention provides a composite aluminum alloy refining agent and an aluminum alloy refining method, and a person skilled in the art can realize the refining by properly improving process parameters by referring to the content. It is expressly intended that all such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the scope of the invention. While the methods and applications of this invention have been described in terms of preferred embodiments, it will be apparent to those of ordinary skill in the art that variations and modifications in the methods and applications described herein, as well as other suitable variations and combinations, may be made to implement and use the techniques of this invention without departing from the spirit and scope of the invention.

A composite aluminum alloy refining agent comprises a first refining agent, a second refining agent and a third refining agent; wherein the content of the first and second substances,

the first refining agent comprises the following components in percentage by mass:

sodium nitrate: 34 percent; graphite powder: 6 percent; cryolite powder: 20 percent; industrial salt: 10 percent; grain refiner: 30 percent;

the second refining agent comprises the following components in percentage by mass:

zinc chloride: 20 percent; graphite powder: 6 percent; hexachloroethane: 4 percent; cryolite powder: 20 percent; CaF₂: 20 percent; industrial salt: 10 percent; grain refiner: 20 percent;

the third refining agent comprises the following components in percentage by mass:

sodium nitrate: 36 percent; graphite powder: 6 percent; industrial salt: 28%; grain refiner: 30 percent; wherein the content of the first and second substances,

the grain refiner is obtained by mixing, grinding and sintering aluminum strontium slag and aluminum alloy mother phase powder in a mass ratio of 1: 1.

The first refining agent, the second refining agent and the third refining agent are all obtained by mixing.

Further, the sintering parameters are as follows: the sintering pressure is 9-50 MPa, the sintering temperature is 450-550 ℃, and the sintering time is 10-20 min.

Further, the aluminum alloy mother phase powder comprises the following elements in percentage by mass: 10% -12%, Mn: 0.2-0.4%, Mg: 0.22 to 0.30 percent of Fe, less than or equal to 0.95 percent of Cu, less than or equal to 1.0 to 2.0 percent of Cu, less than or equal to 1.0 percent of Zn, less than or equal to 0.15 percent of Ti and Zr, less than or equal to 0.01 percent of Sn, less than or equal to 0.01 percent of Pb, and the balance of Al.

A method of refining an aluminum alloy, the method comprising the steps of:

adding the obtained composite aluminum alloy refining agent for degassing:

feeding a first refining agent into the aluminum liquid according to the proportion of 3-4 kg/ton of aluminum liquid, uniformly stirring and degassing for the first time;

feeding the second refining agent into the aluminum liquid according to the proportion of 3-4 kg/ton of aluminum liquid, uniformly stirring and degassing for the second time;

and feeding the third refining agent into the aluminum liquid according to the proportion of 3-4 kg/ton of aluminum liquid, uniformly stirring and degassing for the third time.

Further, each degassing mode adopts 90% nitrogen and 10% CO₂Blowing the aluminum liquid from the furnace bottom. Specifically, nitrogen with the concentration of 90% and CO with the concentration of 10% are adopted₂The molten aluminum is injected into the furnace bottom through the iron pipe of the powder blower.

Furthermore, the air blowing time is 15-20 min each time.

Further, the temperature of the aluminum liquid is kept between 710 and 740 ℃ in the blowing process.

The nitrogen has inactive chemical property, does not have chemical reaction with aluminum liquid and other dissolved gases at the refining temperature, and is not dissolved in the aluminum melt. Introducing nitrogen into the aluminum liquid can form a large amount of bubbles. After the bubbles float out of the liquid surface, hydrogen in the bubbles escapes into the atmosphere, so that the bubbles are continuously generated, namely the hydrogen dissolved in the aluminum liquid can be continuously removed. In the floating process of the bubbles, when the bubbles meet the inclusions, the inclusions are adhered to the surfaces of the bubbles due to the action of surface tension, and the inclusions are removed along with the floating of the bubbles. It can be seen that the inclusions are removed at the same time as the gas is removed.

And degassing and refining by using nitrogen, wherein the refining temperature is controlled within the range of 710-740 ℃, the temperature is too high, the nitrogen can react with aluminum, and the nitrogen pressure is controlled within the range of 10-15 kPa.

Further, the aluminum liquid is obtained by smelting an aluminum alloy raw material; wherein, the aluminum alloy raw material comprises the following elements in percentage by mass: 10% -12%, Mn: 0.2-0.4%, Mg: 0.22 to 0.30 percent of Fe, less than or equal to 0.95 percent of Cu, less than or equal to 1.0 to 2.0 percent of Cu, less than or equal to 1.0 percent of Zn, less than or equal to 0.15 percent of Ti and Zr, less than or equal to 0.01 percent of Sn, less than or equal to 0.01 percent of Pb, and the balance of Al.

Further, the smelting process comprises smelting, stirring, slag skimming, sampling and assay, standing and heat preservation, refining, stirring, slag skimming and online refining.

Further, the method comprises the following steps:

filtering impurities in the aluminum liquid from the degassed aluminum liquid; the filtration can be carried out by a honeycomb ceramic filter;

casting the aluminum liquid with impurities removed into aluminum alloy ingots; the casting may be by a semi-continuous casting method.

The flux refining effect is mainly achieved through adsorption and dissolution with oxide inclusions in the melt. Refining agents based on chlorides, with addition of fluorides, e.g. CaF₂、Na₃AlF₆Etc. to adsorb and dissolve Al₂O₃To increase the purification effect. They are capable of removing oxide inclusions and also some, but not all, of the gases. Adding NaNO₃The aluminum ash temperature of the low-temperature aluminum ash can be effectively improved, the aluminum ash temperature of each point is uniform through stirring, and in the stirring process, metals with low burning points such as metal magnesium in the aluminum ash are combusted to release heat, so that the aluminum ash temperature is continuously increased. If the aluminum ash does not contain combustible substances with low burning point, NaNO is added₃The temperature is increased.

As the temperature rises, the metallic aluminum in the aluminum ash begins to melt to form fine aluminum beads, and the surface tension of the formed liquid metallic aluminum particles is reduced along with the temperature rise. Under the action of stirring, the compact oxide film coated on the surface of the liquid metal aluminum particles is broken by rubbing and rubbing by solid aluminum ash impurities, and the fluidity of aluminum liquid is increased.

During refining, the temperature of the aluminum liquid is firstly adjusted to be 20-30 ℃ higher than the pouring temperature. The flux is scattered on the surface of the aluminum alloy melt, and because the flux used by the aluminum alloy is lower in density than the aluminum liquid, the flux floats on the aluminum alloy melt. Stirring for 5-10 min, standing for 5-10 min, removing slag on the alloy, spraying a layer of covering agent, and pouring after refining.

In the invention, the sodium nitrate is added to effectively raise the aluminum ash temperature of the low-temperature aluminum ash, the aluminum ash temperature of each point is uniform through refining and gas dynamic stirring, and metal magnesium and other low-ignition point metals in the aluminum ash are combusted to release heat in the stirring process, so that the aluminum ash temperature is continuously raised. If the aluminum ash does not contain combustible substances with low burning point, sodium nitrate is added to increase the temperature. As the temperature rises, the metallic aluminum in the aluminum ash begins to melt to form fine aluminum beads, and the surface tension of the formed liquid metallic aluminum particles is reduced along with the temperature rise. Under the action of stirring, the compact oxide film coated on the surface of the liquid metal aluminum particles is broken by rubbing and rubbing by solid aluminum ash impurities, and the fluidity of aluminum liquid is increased.

Zinc chloride and hexachloroethane: the principle of chlorine salt purification is that the chlorine salt reacts with aluminum to generate low boiling point compounds (such as AlCl3 boiling point 182.7 ℃) which are insoluble in aluminum liquid, bubbles are formed in the aluminum liquid, and the effects of degassing and removing impurities are achieved when the bubbles float upwards. Firstly, the interfacial tension between the flux and the melt is improved, and the adsorption effect of the flux on oxides is enhanced; secondly, the fluoride and the aluminum melt have higher reaction capability, and reaction products of aluminum fluoride gas, liquid sodium and the like with surface activity are formed on a liquid aluminum-oxide interface, so that the removal of the oxide is promoted. When the treatment is carried out with only chloride, only a small amount of gaseous product of the aluminumhloride is produced, and the refining effect is not as good as that of the fluoride.

The graphite powder is mainly added with an auxiliary agent for avoiding the too fast temperature rise in the refining process.

The cryolite mainly plays a refining role, such as adsorbing and dissolving Al₂O₃。

Fluorite (CaF)₂) Has the functions of lowering the melting point of refractory substances, promoting the flow of slag and making slag and metal very goodGood separation, desulfurization and dephosphorization in the smelting process, and the like, and enhances the malleability and tensile strength of the metal. The surface tension of the mixed molten salt can be increased, the molten salt adsorbed with oxides is spheroidized, the molten salt is convenient to separate from the melt, the loss caused by aluminum wrapped by solid slag is reduced, and the process of adsorbing and mixing by the flux is accelerated due to the improvement of the surface tension of the flux-melt.

The grain refiner is prepared by mixing, grinding and sintering aluminum strontium slag and aluminum alloy mother phase powder in a mass ratio of 1: the grain refiner will act on the size and texture of the grains within the aluminum alloy casting to form finer grain sizes. Can reduce shrinkage porosity, reduce the size of shrinkage porosity, improve feeding and reduce the tendency of shrinkage porosity formation. The aluminum strontium slag acts on the silicon of the alloy system to change the shape of the eutectic silicon from a long strip shape into fine particles. The deterioration results in improved mechanical properties, in particular tensile strength and elongation.

In order that the present invention may be more readily and clearly understood, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments that are illustrated in the appended drawings.

Example one

As shown in fig. 1, a process flow diagram of an aluminum alloy refining method is shown, and the aluminum alloy refining method comprises the following specific steps:

1. preparing materials: the aluminum alloy section bar comprises the following elements in percentage by mass: 10%, Mn: 0.2%, Mg: 0.22%, Fe: 0.5%, Cu: 1.0%, Zn: 0.5%, Ti + Zr: 0.10%, Sn: 0.01%, Pb: 0.01 percent of Al, and weighing and preparing the raw material components in parts by mass;

2. preparing a grain refiner:

a. uniformly mixing the aluminum strontium slag and the aluminum alloy mother phase powder prepared in the step 1 according to the mass part ratio of 1:1, and grinding into powder for later use; b. b, sintering the mixture powder ground in the step a in a sintering furnace, wherein the sintering pressure is 9-50 MPa, the sintering temperature is 450-550 ℃, and the sintering time is 10-20 min to obtain a grain refiner;

3. smelting: all the raw material components weighed in the step 1 are put into a smelting furnace to be smelted; the smelting is specifically as follows: smelting, stirring, slagging off, sampling and testing, standing and preserving heat, refining, stirring, slagging off and online refining;

4. adding a refining agent for degassing: and (3) mixing the grain refiner prepared in the step (2) with the following components to respectively obtain a first refining agent, a second refining agent and a third refining agent:

5. feeding 3-4 kg of aluminum liquid per ton of aluminum liquid into the aluminum liquid, uniformly stirring a refining agent and the aluminum liquid by a powder sprayer, and degassing; the degassing method adopts 90% nitrogen and 10% CO₂Blowing the uniformly stirred aluminum liquid into the furnace bottom through a powder blower iron pipe for 15-20 min, wherein the temperature of the aluminum liquid is kept at 710-740 ℃ in the blowing process, the first blowing uses a first refining agent, the second uses a second refining agent, the third uses a third refining agent, and the blowing time is 15-20 min;

6. and (3) filtering: filtering impurities in the aluminum liquid by passing the degassed aluminum liquid through a honeycomb ceramic filter;

7. casting: and casting the aluminum liquid with impurities removed into aluminum alloy ingots by a semi-continuous casting method.

The grain size of the aluminum alloy ingot prepared by the embodiment reaches the second level, and the mechanical property of the aluminum alloy casting is as follows: the hardness reaches 90HB, the tensile strength is 220Mpa, the usage amount of the refining agent is 1.5 thousandth of that of the aluminum liquid, the usage amount of the refining agent is reduced, the production cost is reduced, and the production efficiency is also improved.

Example two

The method of this embodiment is substantially the same as the first embodiment except that: the aluminum alloy section bar comprises the following elements in percentage by mass: 12%, Mn: 0.4%, Mg: 0.30%, Fe: 0.95%, Cu: 2.0%, Zn: 1.0%, Ti + Zr: 0.15%, Sn: 0.01%, Pb: 0.01%, and the balance of Al, the total being 100%.

The grain size of the aluminum alloy ingot prepared by the embodiment reaches the second level, and the mechanical property of the aluminum alloy casting is as follows: the hardness reaches 95HB, the tensile strength is 240Mpa, the usage amount of the refining agent is 1.5 thousandth of that of the aluminum liquid, the usage amount of the refining agent is reduced, the production cost is reduced, and the production efficiency is also improved.

EXAMPLE III

The method of this embodiment is substantially the same as the first embodiment except that: the aluminum alloy section bar comprises the following elements in percentage by mass: 11%, Mn: 0.3%, Mg: 0.25%, Fe: 0.8%, Cu: 1.5%, Zn: 0.8%, Ti + Zr: 0.10%, Sn: 0.005%, Pb: 0.005% and the balance Al, the total being 100%.

The grain size of the aluminum alloy ingot prepared by the embodiment reaches the second level, and the mechanical property of the aluminum alloy casting is as follows: the hardness reaches 92HB, the tensile strength is 230Mpa, the usage amount of the refining agent is 1.5 thousandth of that of the aluminum liquid, the usage amount of the refining agent is reduced, the production cost is reduced, and the production efficiency is also improved.

The above embodiments are described in further detail to solve the technical problems, technical solutions and advantages of the present invention, and it should be understood that the above embodiments are only examples of the present invention and are not intended to limit the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.