Aluminum production process

Abstract

The present invention belongs to the field of metal smelting technology, and in particular to the production process of aluminum. The method comprises the following steps: under nitrogen protection, preheating the waste aluminum material and then smelting it, then cooling it to 600-700°C, melting the upper liquid, and removing the slag to obtain the product. The present invention performs a cooling treatment after the smelting is completed, so that the iron in the aluminum liquid is settled to the lower layer, and the upper liquid is collected to ensure that the impurity removal and purification process is thorough and effective, thereby greatly improving the purity and yield of aluminum; during the smelting process, the waste aluminum material is quickly melted by three-stage temperature control; by adding a specific refining agent during the smelting process, the synergistic effect of dichloromethane and N-isobutylpyrrolidone is utilized to further increase the permeability and improve the purity of the aluminum yield; a variety of furnace bodies are used in combination, and the purification is carried out by graded division of labor, which effectively improves the utilization rate of waste aluminum and the purity of aluminum products, and the process is simple, the production cost is low, and it is suitable for industrial production.

Description

Technical Field

[0001] The invention belongs to the technical field of metal smelting, and in particular relates to a production process of aluminum. Background Art

[0002] Aluminum resources are mainly obtained from recycled scrap aluminum, which includes pure aluminum scraps from aluminum processing enterprises, deformed aluminum alloys from old buildings at construction sites, cast aluminum alloys, aluminum core wires and scrap aluminum products. The literature reports that the recycling of scrap aluminum generally involves classification, separation, magnetic separation, crushing, drying and smelting to ultimately obtain pure aluminum or aluminum alloys.

[0003] Chinese invention patent application CN102392139A discloses a process for treating cold aluminum ash slag using a rotary furnace. The specific preparation steps include: crushing the cold aluminum ash slag and screening it into coarse particles for standby use; first adding a special flux accounting for 5-20% of the total input into a rotary furnace with a heating device at the furnace mouth, the special flux consisting of 90-96% chloride and 4-10% fluoride; then lighting the burner to start heating, while rotating the rotary furnace, after the special flux in the rotary furnace is melted, adding 80-95% of the total input coarse particles of cold aluminum ash slag; then rotating and heating, when the aluminum alloy liquid in the cold aluminum ash slag is separated from the ash slag, the aluminum alloy liquid is collected at the bottom, and the ash slag floats on the surface of the aluminum alloy liquid, stop rotating and heating, pour out the aluminum liquid first, and then pour out the solid ash while rotating the rotary furnace. The special flux of the invention improves the interfacial tension between the ash slag and the aluminum alloy, making it easy to separate, and at the same time covers the aluminum to prevent further oxidation, thereby improving the metal recovery rate.

[0004] Another Chinese invention patent application CN102703739A discloses a production process for recycled aluminum. The invention improves the stirring step of the smelting process in the recycled aluminum production process and adopts an air compressor. The air compressor is connected to one end of a vibrating rod through a pipeline, and the other end of the vibrating rod extends into the furnace of the smelting furnace. When stirring, the air compressor is turned on to drive the vibrating rod to vibrate and stir in the furnace, thereby improving product quality and production efficiency.

[0005] Another Chinese invention patent application CN103361487A discloses a method for producing recycled aluminum. In this method, waste aluminum or aluminum ash slag is first classified and stacked, and then separated. The separation is to remove dirt by cleaning and crushing, and remove steel by magnetic separation. The initially pure aluminum is then crushed and sieved to obtain miscellaneous aluminum powder, which is then put into a rotary furnace for combustion reaction to decompose the aluminum slag or waste aluminum into aluminum liquid and aluminum ash; the aluminum liquid is further smelted in a refining furnace to obtain aluminum liquid with higher purity, which is discharged to form aluminum ingots; the aluminum ash discharged from the rotary furnace and the flue gas are passed through a cyclone dust collector to obtain aluminum ash, and the residue contains 1-3% aluminum, which can be provided to steel mills as a smelting additive after packaging.

[0006] Although the above-mentioned secondary aluminum production method can recycle scrap aluminum, due to the immaturity of domestic technology, there is a large gap between separation, magnetic separation and smelting and foreign metal recycling companies. Especially in the smelting process of scrap aluminum, some iron-containing and heavy metal impurities cannot be removed to meet the requirements. The production process also causes environmental pollution of waste gas and wastewater.

[0007] Therefore, there is an urgent need in the art to provide a production process that is simple, low-cost and suitable for industrial production of high-purity aluminum. Summary of the invention

[0008] The present invention aims at solving the problems existing in the prior art and provides a production process of aluminum.

[0009] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0010] The production process of aluminum includes the following steps: under nitrogen protection, preheating the waste aluminum material and then smelting it, then cooling it to 600-700°C, melting the upper layer of liquid, and removing the slag to obtain aluminum.

[0011] Preferably, the temperature is lowered to 640-680°C.

[0012] More preferably, the temperature is lowered to 650°C, 660°C or 670°C.

[0013] Preferably, the waste aluminum material is selected from one or more of waste aluminum slices, waste aluminum core wires, waste aluminum products and waste aluminum alloys.

[0014] Preferably, the waste aluminum material needs to be pretreated, and the pretreatment includes cleaning, crushing, magnetic separation and drying.

[0015] Preferably, the cleaning process comprises adding the waste aluminum material into a cleaning agent, wherein the cleaning agent is a mixture of dichloromethane and N-isobutylpyrrolidone in a volume ratio of 2-3:1.

[0016] Preferably, the preheating temperature is 400-500° C., and the preheating time is 120-150 min.

[0017] More preferably, the preheating temperature is 430-470° C., and the preheating time is 125-140 min.

[0018] More preferably, the preheating temperature is 450° C. and the preheating time is 130 min.

[0019] Preferably, a refining agent needs to be added during the smelting, and the refining agent includes 50-70% potassium chloride, 10-30% sodium carbonate, and 10-30% cryolite powder by weight.

[0020] More preferably, the refining agent comprises 60% potassium chloride, 20% sodium carbonate and 20% cryolite powder by weight.

[0021] Preferably, the smelting includes three stages. The first stage of smelting is to heat up to 600-750°C and keep it for 20-40 minutes; the second stage of smelting is to heat up to 750-850°C and keep it for 60-180 minutes; the third stage of smelting is to cool down to 700-750°C and keep it for 40-90 minutes.

[0022] More preferably, the first stage of smelting is to increase the temperature to 650-700°C and keep it for 25-35 minutes; the second stage of smelting is to increase the temperature to 780-800°C and keep it for 90-150 minutes; the third stage of smelting is to decrease the temperature to 720-750°C and keep it for 60-90 minutes.

[0023] Further preferably, the first stage of smelting is to increase the temperature to 700°C and keep it for 35 minutes; the second stage of smelting is to increase the temperature to 800°C and keep it for 120 minutes; and the third stage of smelting is to decrease the temperature to 720°C and keep it for 60 minutes.

[0024] Preferably, the heating and / or cooling rates are both 10-15°C / min.

[0025] Preferably, the melting temperature is 760-780° C., and the melting time is 120-180 min.

[0026] More preferably, the melting temperature is 770-780° C., and the melting time is 150-170 min.

[0027] More preferably, the melting temperature is 780° C. and the melting time is 160 min.

[0028] Preferably, the deslagging temperature is 700-740° C., and the deslagging time is 60-120 min.

[0029] More preferably, the deslagging temperature is 710-730° C., and the deslagging time is 90-120 min.

[0030] More preferably, the slag removal temperature is 720° C. and the slag removal time is 90 min.

[0031] Preferably, after the slag removal is completed, an aluminum ingot needs to be cast, and the temperature of the cast aluminum ingot is 680-720°C.

[0032] Further preferably, the temperature of the cast aluminum ingot is 700-720°C.

[0033] More preferably, the temperature of the cast aluminum ingot is 700°C.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] (1) The present invention performs a cooling treatment after smelting, so that the iron in the aluminum liquid settles to the lower layer, and the upper liquid is collected to ensure that the impurity removal and purification process is thorough and effective, thereby greatly improving the purity and yield of aluminum.

[0036] (2) The present invention adds waste aluminum to a specific cleaning agent and utilizes the synergistic effect of dichloromethane and N-isobutylpyrrolidone to further enhance the penetration ability, destroy the paint layer of the waste aluminum, increase the paint removal efficiency, and improve the quality of aluminum.

[0037] (3) During the smelting process, the present invention uses three-stage temperature control to make the waste aluminum material melt quickly, with a low burn-out rate, low energy consumption, and small discharge volume, thereby realizing the recovery and reuse of aluminum metal; by adding a specific proportion of refining agent during the smelting process, the purity of the aluminum yield is further improved.

[0038] (4) The present invention adopts a combination of multiple furnace bodies and graded and divided purification, which can effectively improve the utilization rate of waste aluminum and the purity of aluminum products. The process is simple, the production cost is low, and it is suitable for industrial production. DETAILED DESCRIPTION

[0039] It is worth noting that the raw materials used in the present invention are all common commercially available products.

[0040] Example 1

[0041] A production process of aluminum, the steps are as follows:

[0042] (1) Pretreatment: Disassemble the scrap aluminum products and remove the steel and other nonferrous metal parts connected to the aluminum materials; screen out the non-metallic waste such as plastic, rubber and other nonferrous metal parts of the scrap aluminum slices; then put the raw materials into a mixed solution of dichloromethane and N-isobutylpyrrolidone with a volume ratio of 2:1 at a material-liquid ratio of 1g:20mL for cleaning to destroy the paint layer of the scrap aluminum materials; soak for 20 minutes; after cleaning, crush to a particle diameter of 50μm; then separate the steel materials through a magnetic field device; dry to obtain mixed aluminum powder for standby use.

[0043] (2) Under nitrogen protection, weigh 20 kg of mixed aluminum powder and put it into the preheating kiln, preheat it at 450°C for 130 minutes, and then put it into the upper furnace for smelting to melt the aluminum product. During smelting, add 0.5 kg of refining agent (by weight percentage, the refining agent consists of 60% potassium chloride, 20% sodium carbonate and 20% cryolite powder), and set the smelting temperature gradient: in the first stage of smelting, heat up to 700°C at a heating rate of 10°C / min and keep it for 35 minutes; in the second stage of smelting, heat up to 800°C at a heating rate of 10°C / min and keep it for 120 minutes; in the third stage of smelting, cool down to 720°C at a cooling rate of 15°C / min and keep it for 60 minutes. After the smelting is completed, aluminum liquid is obtained. When the aluminum liquid drops to 650°C, the iron in the aluminum liquid settles to the lower layer, and the upper liquid is collected.

[0044] (3) Under nitrogen protection, the upper layer of liquid was put into the lower furnace to melt the master alloy, the melting temperature was set to 780°C, and the temperature was kept for 160 minutes, and then put into the rotary furnace for slag removal, and the slag removal temperature was set to 720°C and kept for 90 minutes. Finally, a casting machine was used for online casting to form an aluminum ingot. When the online casting temperature was 720°C, the purity of the obtained aluminum ingot was 99.99% and the yield was 92.8%.

[0045] Example 2

[0046] A production process of aluminum, the steps are as follows:

[0047] (1) Pretreatment: Separate the steel core from the waste aluminum core wire and wind the aluminum wire into a coil; screen out the non-metallic waste and other non-ferrous metal parts of the waste alloy aluminum; then, according to the material-liquid ratio of 1 g:20 mL, put the raw materials into a mixed solution of dichloromethane and N-isobutylpyrrolidone with a volume ratio of 3:1 for cleaning to destroy the paint layer of the waste aluminum material; soak for 30 minutes; after cleaning, crush to a particle diameter of 50 μm; separate the steel material through a device with a magnetic field; dry to obtain mixed aluminum powder for standby use.

[0048] (2) Under nitrogen protection, weigh 20 kg of mixed aluminum powder and put it into the preheating kiln, preheat it at 400 ° C for 150 minutes, and then put it into the upper furnace for smelting to melt the aluminum product. During smelting, add 0.5 kg of refining agent (by weight percentage, the refining agent consists of 50% potassium chloride, 20% sodium carbonate and 30% cryolite powder), and set the smelting temperature gradient: the first stage of smelting is heated to 600 ° C at a heating rate of 10 ° C / min and maintained for 40 minutes; the second stage of smelting is heated to 750 ° C at a heating rate of 10 ° C / min and maintained for 180 minutes; the third stage of smelting is cooled to 750 ° C at a cooling rate of 15 ° C / min and maintained for 40 minutes. After the smelting is completed, aluminum liquid is obtained. When the aluminum liquid drops to 660 ° C, the iron in the aluminum liquid settles to the lower layer, and the upper liquid is collected.

[0049] (3) Under nitrogen protection, the upper layer of liquid was put into the lower furnace to melt the master alloy, the melting temperature was set to 770°C, and the temperature was kept for 170 minutes, and then put into the rotary furnace for slag removal, and the slag removal temperature was set to 700°C and kept for 120 minutes. Finally, a casting machine was used for online casting to form an aluminum ingot. When the online casting temperature was 730°C, the purity of the obtained aluminum ingot was 99.97%, and the yield was 93.5%.

[0050] Example 3

[0051] A production process of aluminum, the steps are as follows:

[0052] (1) Pretreatment: Disassemble the scrap aluminum products and remove the steel and other nonferrous metal parts connected to the aluminum materials; screen out the non-metallic scrap aluminum alloy and other nonferrous metal parts; then put the raw materials into a mixed solution of dichloromethane and N-isobutylpyrrolidone with a volume ratio of 2:1 at a material-liquid ratio of 1g:20mL for cleaning to destroy the paint layer of the scrap aluminum materials; soak for 25 minutes; after cleaning, crush to a particle diameter of 50μm; separate the steel materials through a magnetic field device; dry to obtain mixed aluminum powder for standby use.

[0053] (2) Under nitrogen protection, weigh 20kg of mixed aluminum powder and put it into the preheating kiln, preheat it at 500℃ for 120min, and then put it into the upper furnace for smelting to melt the aluminum product. During smelting, add 0.5kg of refining agent (by weight percentage, the refining agent consists of 70% potassium chloride, 10% sodium carbonate and 20% cryolite powder), and set the smelting temperature gradient: in the first stage of smelting, heat up to 6750℃ at a heating rate of 15℃ / min and keep it for 20min; in the second stage of smelting, heat up to 850℃ at a heating rate of 15℃ / min and keep it for 60min; in the third stage of smelting, cool down to 700℃ at a cooling rate of 10℃ / min and keep it for 90min. After smelting, aluminum liquid is obtained. When the aluminum liquid drops to 670℃, the iron in the aluminum liquid settles to the lower layer, and the upper liquid is collected.

[0054] (3) Under nitrogen protection, the upper layer of liquid was put into the lower furnace to melt the master alloy, the melting temperature was set to 780°C, and the temperature was kept for 120 minutes, and then put into the rotary furnace for slag removal, and the slag removal temperature was set to 740°C and kept for 80 minutes. Finally, a casting machine was used for online casting to form an aluminum ingot. When the online casting temperature was 710°C, the purity of the obtained aluminum ingot was 99.98%, and the yield was 93.1%.

[0055] Comparative Example 1

[0056] The same as Example 1, the only difference is that the cleaning agent in step (1) is N-isobutylpyrrolidone.

[0057] (1) Pretreatment: Disassemble the scrap aluminum products and remove the steel and other nonferrous metal parts connected to the aluminum materials; screen out the non-metallic waste such as plastic, rubber and other nonferrous metal parts of the scrap aluminum slices, and then put the raw materials into N-isobutylpyrrolidone at a material-liquid ratio of 1g:20mL for cleaning to destroy the paint layer of the scrap aluminum materials, soak for 20 minutes, and crush them to a particle diameter of 50μm after cleaning, and then separate the steel materials through a magnetic field device, dry them, and obtain mixed aluminum powder for standby use.

[0058] (2) Under nitrogen protection, weigh 20 kg of mixed aluminum powder and put it into the preheating kiln, preheat it at 450°C for 130 minutes, and then put it into the upper furnace for smelting to melt the aluminum product. During smelting, add 0.5 kg of refining agent (by weight percentage, the refining agent consists of 60% potassium chloride, 20% sodium carbonate and 20% cryolite powder), and set the smelting temperature gradient: in the first stage of smelting, heat up to 700°C at a heating rate of 10°C / min and keep it for 35 minutes; in the second stage of smelting, heat up to 800°C at a heating rate of 10°C / min and keep it for 120 minutes; in the third stage of smelting, cool down to 720°C at a cooling rate of 15°C / min and keep it for 60 minutes. After the smelting is completed, aluminum liquid is obtained. When the aluminum liquid drops to 650°C, the iron in the aluminum liquid settles to the lower layer, and the upper liquid is collected.

[0059] (3) Under nitrogen protection, the upper liquid is put into the lower furnace to melt the master alloy, the melting temperature is set to 780°C, and the temperature is kept for 160 minutes, and then put into the rotary furnace for slag removal, and the slag removal temperature is set to 720°C and kept for 90 minutes. Finally, a casting machine is used for online casting to form an aluminum ingot. When the online casting temperature is 720°C, the purity of the obtained aluminum ingot is 94.1% and the yield is 85.0%.

[0060] Comparative Example 2

[0061] The same as Example 1, the only difference is that the cleaning agent in step (1) is dichloromethane.

[0062] (1) Pretreatment: Disassemble the scrap aluminum products and remove the steel and other non-ferrous metal parts connected to the aluminum materials; screen out the non-metallic waste such as plastic, rubber and other non-ferrous metal parts of the scrap aluminum slices, and then put the raw materials into dichloromethane at a material-liquid ratio of 1g:20mL for cleaning to destroy the paint layer of the scrap aluminum materials, soak for 20 minutes, and crush them to a particle diameter of 50μm after cleaning, and then separate the steel materials through a magnetic field device, dry them, and obtain mixed aluminum powder for standby use.

[0063] (2) Under nitrogen protection, weigh 20 kg of mixed aluminum powder and put it into the preheating kiln, preheat it at 450°C for 130 minutes, and then put it into the upper furnace for smelting to melt the aluminum product. During smelting, add 0.5 kg of refining agent (by weight percentage, the refining agent consists of 60% potassium chloride, 20% sodium carbonate and 20% cryolite powder), and set the smelting temperature gradient: in the first stage of smelting, heat up to 700°C at a heating rate of 10°C / min and keep it for 35 minutes; in the second stage of smelting, heat up to 800°C at a heating rate of 10°C / min and keep it for 120 minutes; in the third stage of smelting, cool down to 720°C at a cooling rate of 15°C / min and keep it for 60 minutes. After the smelting is completed, aluminum liquid is obtained. When the aluminum liquid drops to 650°C, the iron in the aluminum liquid settles to the lower layer, and the upper liquid is collected.

[0064] (3) Under nitrogen protection, the upper layer of liquid was put into the lower furnace to melt the master alloy, the melting temperature was set to 780°C, and the temperature was kept for 160 minutes, and then put into the rotary furnace for slag removal, and the slag removal temperature was set to 720°C and kept for 90 minutes. Finally, a casting machine was used for online casting to form an aluminum ingot. When the online casting temperature was 720°C, the purity of the obtained aluminum ingot was 95.3% and the yield was 83.2%.

[0065] Comparative Example 3

[0066] The same as Example 1, the only difference is that in step (2), the refining agent is: by weight percentage, the refining agent is 60% potassium chloride, 20% sodium hexafluoroaluminate, and 20% cryolite powder.

[0067] (1) Pretreatment: Disassemble the scrap aluminum products and remove the steel and other nonferrous metal parts connected to the aluminum materials; screen out the non-metallic waste such as plastic, rubber and other nonferrous metal parts of the scrap aluminum slices; then put the raw materials into a mixed solution of dichloromethane and N-isobutylpyrrolidone with a volume ratio of 2:1 at a material-liquid ratio of 1g:20mL for cleaning to destroy the paint layer of the scrap aluminum materials; soak for 20 minutes; after cleaning, crush to a particle diameter of 50μm; then separate the steel materials through a magnetic field device; dry to obtain mixed aluminum powder for standby use.

[0068] (2) Under nitrogen protection, weigh 20 kg of mixed aluminum powder and put it into the preheating kiln, preheat it at 450°C for 130 minutes, and then put it into the upper furnace for smelting to melt the aluminum product. During smelting, add 0.5 kg of refining agent (by weight percentage, the refining agent consists of 60% potassium chloride, 20% sodium hexafluoroaluminate and 20% cryolite powder), and set the smelting temperature gradient: in the first stage of smelting, heat up to 700°C at a heating rate of 10°C / min and keep it for 35 minutes; in the second stage of smelting, heat up to 800°C at a heating rate of 10°C / min and keep it for 120 minutes; in the third stage of smelting, cool down to 720°C at a cooling rate of 15°C / min and keep it for 60 minutes. After the smelting is completed, aluminum liquid is obtained. When the aluminum liquid drops to 650°C, the iron in the aluminum liquid settles to the lower layer, and the upper liquid is collected.

[0069] (3) Under nitrogen protection, the upper layer of liquid was put into the lower furnace to melt the master alloy, the melting temperature was set to 780°C, and the temperature was kept for 160 minutes, and then put into the rotary furnace for slag removal, and the slag removal temperature was set to 720°C and kept for 90 minutes. Finally, a casting machine was used for online casting to form an aluminum ingot. When the online casting temperature was 720°C, the purity of the obtained aluminum ingot was 92.8%, and the yield was 87.3%.

[0070] Comparative Example 4

[0071] The same as Example 1, the only difference is that the aluminum liquid is not cooled in step (2).

[0072] A production process of aluminum, the steps are as follows:

[0073] (1) Pretreatment: Disassemble the scrap aluminum products and remove the steel and other nonferrous metal parts connected to the aluminum materials; screen out the non-metallic waste such as plastic, rubber and other nonferrous metal parts of the scrap aluminum slices; then put the raw materials into a mixed solution of dichloromethane and N-methyl-2-pyrrolidone with a volume ratio of 1:2 at a material-liquid ratio of 1g:20mL for cleaning to destroy the paint layer of the scrap aluminum materials; soak for 20 minutes; after cleaning, crush to a particle diameter of 50μm; then separate the steel materials through a magnetic field device; dry to obtain mixed aluminum powder for standby use.

[0074] (2) Under nitrogen protection, 20 kg of mixed aluminum powder was weighed and put into the preheating kiln, preheated at 450 ° C for 130 min, and then put into the upper furnace for smelting to melt the aluminum product. 0.5 kg of refining agent was added during smelting (the refining agent was composed of 60% potassium chloride, 20% sodium carbonate and 20% cryolite powder by weight percentage). The smelting temperature gradient was set: in the first stage of smelting, the temperature was increased to 700 ° C at a heating rate of 10 ° C / min and maintained for 35 min; in the second stage of smelting, the temperature was increased to 800 ° C at a heating rate of 10 ° C / min and maintained for 120 min; in the third stage of smelting, the temperature was reduced to 720 ° C at a cooling rate of 15 ° C / min and maintained for 60 min. After the smelting, aluminum liquid was obtained.

[0075] (3) Under nitrogen protection, the aluminum liquid is put into the lower furnace to melt the master alloy, the melting temperature is set to 780°C, and the temperature is maintained for 160 minutes, and then put into the rotary furnace for slag removal, and the slag removal temperature is set to 720°C and maintained for 90 minutes. Finally, a casting machine is used for online casting to form an aluminum ingot. When the online casting temperature is 720°C, the purity of the obtained aluminum ingot is 90.3%, and the yield is 82.4%.

[0076] Comparative Example 5

[0077] The same as Example 1, the only difference is that the temperature gradient of smelting in step (2) is different.

[0078] A production process of aluminum, the steps are as follows:

[0079] (1) Pretreatment: Disassemble the scrap aluminum products and remove the steel and other nonferrous metal parts connected to the aluminum materials; screen out the non-metallic waste such as plastic, rubber and other nonferrous metal parts of the scrap aluminum slices; then put the raw materials into a mixed solution of dichloromethane and N-methyl-2-pyrrolidone with a volume ratio of 1:2 at a material-liquid ratio of 1g:20mL for cleaning to destroy the paint layer of the scrap aluminum materials; soak for 20 minutes; after cleaning, crush to a particle diameter of 50μm; then separate the steel materials through a magnetic field device; dry to obtain mixed aluminum powder for standby use.

[0080] (2) Under nitrogen protection, weigh 20 kg of mixed aluminum powder and put it into the preheating kiln, preheat it at 450°C for 130 minutes, and then put it into the upper furnace for smelting to melt the aluminum product. During smelting, add 0.5 kg of refining agent (by weight percentage, the refining agent consists of 60% potassium chloride, 20% sodium carbonate and 20% cryolite powder), and set the smelting temperature gradient: in the first stage of smelting, heat up to 600°C at a heating rate of 10°C / min and keep it for 20 minutes; in the second stage of smelting, heat up to 700°C at a heating rate of 10°C / min and keep it for 25 minutes; in the third stage of smelting, cool down to 680°C at a cooling rate of 15°C / min and keep it for 40 minutes. After the smelting is completed, aluminum liquid is obtained. When the aluminum liquid drops to 650°C, the iron in the aluminum liquid settles to the lower layer, and the upper liquid is collected.

[0081] (3) Under nitrogen protection, the upper layer of liquid was put into the lower furnace to melt the master alloy, the melting temperature was set to 780°C, and the temperature was kept for 160 minutes, and then put into the rotary furnace for slag removal, and the slag removal temperature was set to 720°C and kept for 90 minutes. Finally, a casting machine was used for online casting to form an aluminum ingot. When the online casting temperature was 720°C, the purity of the obtained aluminum ingot was 91.5%, and the yield was 88.8%.

[0082] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A process for producing aluminum, characterized in that: The method comprises the following steps: preheating the waste aluminum material under nitrogen protection and then melting it, cooling it to 600-700°C, melting the upper layer of liquid, and removing the slag to obtain: The waste aluminum material needs to be pretreated, and the pretreatment includes cleaning, crushing, magnetic separation and drying. The cleaning process includes adding the waste aluminum material to a cleaning agent, and the cleaning agent is a mixture of dichloromethane and N-isobutylpyrrolidone in a volume ratio of 2-3:

1. The smelting needs to add a refining agent, which is composed of 50-70% potassium chloride, 10-30% sodium carbonate, and 10-30% cryolite powder by weight percentage. The smelting includes three stages. The first stage of smelting is heating to 600-750°C and maintaining for 20-40 minutes; The second stage of smelting is to increase the temperature to 750-850°C and keep it for 60-180 minutes; the third stage of smelting is to reduce the temperature to 700-750°C and keep it for 40-90 minutes.

2. The production process according to claim 1, characterized in that: The waste aluminum material is selected from one or both of waste aluminum slices and waste aluminum core wires.

3. The production process according to claim 1, characterized in that: The waste aluminum material is selected from one or both of waste aluminum products and waste alloy aluminum.

4. The production process according to claim 1, characterized in that: The preheating temperature is 400-500° C., and the preheating time is 120-150 min.

5. The production process according to claim 1, characterized in that: The heating and / or cooling rates are both 10-15°C / min.

6. The production process according to claim 1, characterized in that: The melting temperature is 760-780° C., and the melting time is 120-180 min.

7. The production process according to any one of claims 1 to 6, characterized in that: The slag removal temperature is 700-740°C, the slag removal time is 60-120 min, and after the slag removal is completed, an aluminum ingot is cast, and the temperature of the cast aluminum ingot is 680-720°C.