Aluminum ash resource utilization method

Abstract

The invention belongs to the technical field of aluminum ash treatment, and particularly relates to an aluminum ash resource utilization method. The aluminum ash resource utilization method provided by the invention comprises the following steps: crushing and sieving secondary aluminum ash, then mixing the sieved fine material with water to obtain slurry, and filtering the slurry to obtain a filter cake; drying, crushing and screening the filter cake to obtain filter cake particles; adding the filter cake particles into a roasting furnace, then introducing inert gas into the roasting furnace, heating the roasting furnace to 800-1000 DEG C, roasting the filter cake particles, then introducing hydrogen fluoride gas into the roasting furnace, intermittently introducing hydrogen, cooling the filter cake particles to room temperature after roasting, and crushing to obtain the aluminum ash. According to the aluminum ash resource utilization method, the silicon content in the aluminum ash slag can be effectively reduced, meanwhile, an aluminum fluoride additive does not need to be additionally added, granulation treatment is not needed, and the process is simple.

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum ash processing, and specifically relates to a method for resource utilization of aluminum ash. Background Art

[0002] A large amount of waste slag, namely aluminum ash, is generated during the processing and smelting of aluminum materials. After further processing, such as physical or chemical treatment to recover aluminum, waste slag is also formed during the recovery of aluminum, which is secondary aluminum ash. The secondary aluminum ash has a complex composition, mainly containing aluminum oxide, silicon oxide, calcium oxide, iron oxide, inorganic salts, etc. It may also contain aluminum nitride and other components. Therefore, the resource treatment of aluminum ash has been mentioned and paid attention to by more and more people.

[0003] In the field of resource utilization of aluminum ash, it involves washing the aluminum ash. After washing, a large amount of waste slag will be produced, namely aluminum ash slag. The aluminum ash slag contains a high content of silicon, and the silicon element will form oxides during the high-temperature calcination process. Such oxides will affect the wear resistance and corrosion resistance of the material in the subsequent resource utilization process. Therefore, it is necessary to remove silicon from the aluminum ash slag.

[0004] The prior art discloses a method for desiliconizing aluminum ash slag after water washing, which requires the additional addition of aluminum fluoride additives and requires granulation treatment. The process is complicated and a large amount of aluminum fluoride needs to be added to achieve a better desiliconization effect. Therefore, it is necessary to study a new method for desiliconizing aluminum ash slag after water washing. Summary of the invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defects of the existing method of desiliconizing aluminum ash slag after water washing, which requires the additional addition of aluminum fluoride additives and requires granulation treatment, has a complex process, and requires the addition of a large amount of aluminum fluoride to achieve a better desiliconization effect, thereby providing a method for resource utilization of aluminum ash.

[0006] In order to solve the above problems, the scheme of the present invention is as follows:

[0007] A method for resource utilization of aluminum ash comprises the following steps:

[0008] 1) crushing and sieving the secondary aluminum ash, then mixing the sieved fine material with water to obtain slurry, filtering the slurry to obtain a filter cake;

[0009] 2) drying, crushing and sieving the filter cake to obtain filter cake particles;

[0010] 3) adding the filter cake particles into a calcining furnace, then introducing an inert gas into the calcining furnace, heating the calcining furnace to 800-1000° C. to calcine the filter cake particles, then introducing hydrogen fluoride gas into the calcining furnace, introducing hydrogen into the calcining furnace after introducing the hydrogen fluoride gas for 8-15 minutes, stopping introducing hydrogen into the calcining furnace after introducing the hydrogen for 8-15 minutes, introducing hydrogen into the calcining furnace again after 8-15 minutes, during which time the inert gas and hydrogen fluoride gas are continuously introduced into the calcining furnace, and after the calcination is completed, cooling the filter cake particles to room temperature, crushing them, and obtaining aluminum ash slag.

[0011] Preferably, in step 3), the filter cake particles are added to a calcining furnace, and then argon gas is introduced into the calcining furnace, and the argon gas introduction rate is 280-350sccm. The calcining furnace is heated to 800-1000°C to calcine the filter cake particles, and then hydrogen fluoride gas is introduced into the calcining furnace, and the hydrogen fluoride gas introduction rate is 20-40sccm. After the hydrogen fluoride gas is introduced for 8-15 minutes, hydrogen gas is introduced into the calcining furnace, and the hydrogen introduction rate is 8-15sccm. After the hydrogen gas is introduced for 8-15 minutes, the introduction of hydrogen into the calcining furnace is stopped. After 8-15 minutes, hydrogen gas is introduced into the calcining furnace again for 8-15 minutes, and the hydrogen introduction rate is 8-15sccm. During this period, argon gas and hydrogen fluoride gas are continuously introduced into the calcining furnace. After the calcination is completed, the filter cake particles are cooled to room temperature and crushed to obtain aluminum ash slag.

[0012] Preferably, the total roasting time is 24-60 hours. It can be understood that in the present invention, when the roasting furnace is heated to 800-1000°C, hydrogen fluoride gas is introduced into the roasting furnace at the same time, and the total roasting time is calculated from the time when the roasting furnace is heated to 800-1000°C.

[0013] Preferably, the inert gas is argon.

[0014] The present invention does not specifically limit the composition of the secondary aluminum ash. Optionally, the secondary aluminum ash includes the following components in weight percentage: Al2O3 50-65%, SiO2 5-12%, Na2O 5-9%, Fe2O3 1-4%, and CaO 4-7%.

[0015] Preferably, during the roasting process, the gas in the roasting furnace is discharged through the gas outlet of the roasting furnace, collected and reserved.

[0016] Preferably, after crushing in step 1), the product is sieved through a 80-120 mesh screen.

[0017] Preferably, in step 1), the fine material and water are mixed at a liquid-to-solid ratio of (6-12):1.

[0018] Preferably, in step 1), the fine material and water are mixed at a liquid-to-solid ratio of 8:1.

[0019] Preferably, in step 2), the drying temperature is 90-100° C. and the drying time is 4-10 h.

[0020] Preferably, the particle size of the filter cake particles is 1-5 mm.

[0021] The technical solution of the present invention has the following advantages:

[0022] The resource utilization method of aluminum ash provided by the present invention comprises the following steps: firstly crushing and screening secondary aluminum ash, then preparing slurry, filtering the slurry to obtain filter cake, drying, crushing and screening the filter cake to obtain filter cake particles; adding the filter cake particles into a roasting furnace, introducing inert gas into the roasting furnace, heating the roasting furnace to 800-1000° C. to roast the filter cake particles, then introducing hydrogen fluoride gas into the roasting furnace, introducing hydrogen into the roasting furnace after the hydrogen fluoride gas is introduced for 8-15 minutes, stopping introducing hydrogen into the roasting furnace after the hydrogen is introduced for 8-15 minutes, introducing hydrogen into the roasting furnace again for 8-15 minutes after 8-15 minutes, during which the inert gas and hydrogen fluoride gas are continuously introduced into the roasting furnace, cooling the filter cake particles to room temperature after the roasting is completed, crushing, Aluminum ash slag is obtained. In the process of the present invention, inert gas and hydrogen fluoride gas are introduced in sequence during the roasting process of filter cake particles. The hydrogen fluoride gas reacts with silicon oxide under high-temperature roasting conditions to form silicon tetrafluoride gas. The silicon tetrafluoride gas is discharged from the roasting furnace along with the inert gas to achieve the desiliconization effect. At the same time, the present invention intermittently introduces a proper amount of hydrogen while introducing the inert gas and hydrogen fluoride gas. Since the filter cake is in a granular form, when silicon dioxide inside the granular form reacts with hydrogen fluoride gas to generate silicon tetrafluoride gas, the silicon tetrafluoride gas reacts with hydrogen to generate elemental silicon and hydrogen fluoride before overflowing. The elemental silicon can be discharged along with the inert gas, and the hydrogen fluoride can further react with silicon dioxide inside the granules to generate silicon tetrafluoride gas. This process is repeated, thereby greatly improving the desiliconization effect of the filter cake particles. In addition, the inventors found that if hydrogen is continuously introduced along with the inert gas and hydrogen fluoride gas, the silicon removal effect will be limited. It is speculated that this may be due to the complex composition of the filter cake particles. The addition of hydrogen will reduce some of the components. The reduced components may block the internal passages of the particles or cover the surface of the silicon dioxide, thereby affecting the contact between the silicon dioxide and hydrogen fluoride. The present invention uses an intermittent method of introducing hydrogen and finds that this problem can be effectively solved. The aluminum ash resource utilization method provided by the present invention can effectively reduce the silicon content in the aluminum ash slag, and at the same time, no additional aluminum fluoride additives are required, and no granulation treatment is required, and the process is simple. DETAILED DESCRIPTION

[0023] The following examples are provided for further understanding of the present invention, but are not intended to limit the best mode of implementation and do not limit the scope of protection of the present invention.

[0024] The experimental steps or conditions not specified in the following embodiments of the present invention can be implemented according to the conventional experimental steps and conditions used in the existing literature in the field. The reagents or instruments used without specifying the manufacturer are all conventional reagents or instruments that can be purchased commercially.

[0025] The secondary aluminum ash used in the following examples or comparative examples includes the following components in weight percentage: Al2O3 64.5%, SiO2 10.8%, Na2O 7.8%, Fe2O3 2.5%, and CaO 6.4%.

[0026] Example 1

[0027] This embodiment provides a method for resource utilization of aluminum ash, comprising the following steps:

[0028] 1) crushing the secondary aluminum ash, passing it through a 100-mesh sieve, and then mixing the sieved fine material with water at a liquid-to-solid ratio of 8:1 to obtain a slurry, filtering the slurry to obtain a filter cake and a filtrate;

[0029] 2) Dry the filter cake at 100°C for 5 hours, crush and sieve to obtain filter cake particles with a particle size of 1-2 mm;

[0030] 3) Add the filter cake particles into a roasting furnace, then introduce argon gas into the roasting furnace, the argon gas flow rate is 300sccm, heat the roasting furnace to 900°C to roast the filter cake particles, then introduce hydrogen fluoride gas into the roasting furnace, the hydrogen fluoride gas flow rate is 30sccm, and then introduce hydrogen into the roasting furnace after 10 minutes of hydrogen fluoride gas introduction, the hydrogen gas flow rate is 10sccm, and stop introducing hydrogen into the roasting furnace after 10 minutes of hydrogen introduction. After 10 minutes, introduce hydrogen into the roasting furnace again for 10 minutes, the hydrogen gas flow rate is 10sccm, and argon and hydrogen fluoride gases are continuously introduced into the roasting furnace during the roasting. The total roasting time is 40 minutes. During the roasting, the gas in the roasting furnace is discharged through the gas outlet of the roasting furnace, collected, and used for standby. After the roasting is completed, the filter cake particles are cooled to room temperature and crushed to obtain aluminum ash slag. The silicon element in the aluminum ash slag is detected, and the silicon content is 0.9%.

[0031] Example 2

[0032] This embodiment provides a method for resource utilization of aluminum ash, comprising the following steps:

[0033] 1) crushing the secondary aluminum ash, passing it through a 100-mesh sieve, and then mixing the sieved fine material with water at a liquid-to-solid ratio of 8:1 to obtain a slurry, filtering the slurry to obtain a filter cake and a filtrate;

[0034] 2) Dry the filter cake at 100°C for 5 hours, crush and sieve to obtain filter cake particles with a particle size of 1-2 mm;

[0035] 3) Add the filter cake particles into a roasting furnace, then introduce argon gas into the roasting furnace, the argon gas introduction flow rate is 280sccm, heat the roasting furnace to 940°C to roast the filter cake particles, then introduce hydrogen fluoride gas into the roasting furnace, the hydrogen fluoride gas introduction flow rate is 32sccm, and then introduce hydrogen into the roasting furnace after the hydrogen fluoride gas is introduced for 12 minutes, the hydrogen introduction flow rate is 15sccm, and the introduction of hydrogen into the roasting furnace is stopped after the hydrogen is introduced for 12 minutes. After 12 minutes, hydrogen is introduced into the roasting furnace again for 10 minutes, the hydrogen introduction flow rate is 15sccm, and argon and hydrogen fluoride gases are continuously introduced into the roasting furnace during the roasting. The total roasting time is 46 minutes. During the roasting, the gas in the roasting furnace is discharged through the gas outlet of the roasting furnace, collected, and used for standby. After the roasting is completed, the filter cake particles are cooled to room temperature and crushed to obtain aluminum ash slag, and the silicon element in the aluminum ash slag is detected, and the silicon content is 0.5%.

[0036] Example 3

[0037] This embodiment provides a method for resource utilization of aluminum ash, comprising the following steps:

[0038] 1) crushing the secondary aluminum ash, passing it through a 100-mesh sieve, and then mixing the sieved fine material with water at a liquid-to-solid ratio of 8:1 to obtain a slurry, filtering the slurry to obtain a filter cake and a filtrate;

[0039] 2) drying the filter cake at 100°C for 8 hours, crushing and sieving to obtain filter cake particles with a particle size of 1-2 mm;

[0040] 3) Add the filter cake particles into a roasting furnace, then introduce argon gas into the roasting furnace, the argon gas introduction flow rate is 350sccm, heat the roasting furnace to 950°C to roast the filter cake particles, then introduce hydrogen fluoride gas into the roasting furnace, the hydrogen fluoride gas introduction flow rate is 40sccm, and then introduce hydrogen into the roasting furnace after the hydrogen fluoride gas is introduced for 15 minutes, the hydrogen introduction flow rate is 15sccm, and the introduction of hydrogen into the roasting furnace is stopped after the hydrogen is introduced for 15 minutes. After 15 minutes, hydrogen is introduced into the roasting furnace again for 15 minutes, the hydrogen introduction flow rate is 15sccm, and argon and hydrogen fluoride gases are continuously introduced into the roasting furnace during the roasting. The total roasting time is 60 minutes. During the roasting, the gas in the roasting furnace is discharged through the gas outlet of the roasting furnace, collected, and used for standby. After the roasting is completed, the filter cake particles are cooled to room temperature and crushed to obtain aluminum ash slag. The silicon element in the aluminum ash slag is detected, and the silicon content is 0.3%.

[0041] Example 4

[0042] This embodiment provides a method for resource utilization of aluminum ash, comprising the following steps:

[0043] 1) crushing the secondary aluminum ash, passing it through a 100-mesh sieve, and then mixing the sieved fine material with water at a liquid-to-solid ratio of 8:1 to obtain a slurry, filtering the slurry to obtain a filter cake and a filtrate;

[0044] 2) Dry the filter cake at 100°C for 5 hours, crush and sieve to obtain filter cake particles with a particle size of 1-2 mm;

[0045] 3) Add the filter cake particles into a roasting furnace, then introduce argon gas into the roasting furnace, the argon gas flow rate is 300sccm, heat the roasting furnace to 950°C to roast the filter cake particles, then introduce hydrogen fluoride gas into the roasting furnace, the hydrogen fluoride gas flow rate is 35sccm, and then introduce hydrogen into the roasting furnace after the hydrogen fluoride gas is introduced for 12 minutes, the hydrogen gas flow rate is 12sccm, and the hydrogen gas introduction into the roasting furnace is stopped after the hydrogen gas is introduced for 12 minutes. After 10 minutes, hydrogen gas is introduced into the roasting furnace again for 10 minutes, the hydrogen gas flow rate is 12sccm, and argon gas and hydrogen fluoride gas are continuously introduced into the roasting furnace during the roasting. The total roasting time is 44 minutes. During the roasting, the gas in the roasting furnace is discharged through the gas outlet of the roasting furnace, collected, and used for standby. After the roasting is completed, the filter cake particles are cooled to room temperature and crushed to obtain aluminum ash slag. The silicon element in the aluminum ash slag is detected, and the silicon content is 0.7%.

[0046] Comparative Example 1

[0047] The present comparative example provides a method for resource utilization of aluminum ash, which differs from Example 1 in that in step 3), filter cake particles are added to a calcining furnace, and then argon gas is introduced into the calcining furnace, and the argon gas introduction flow rate is 300sccm. The calcining furnace is heated to 900°C to calcine the filter cake particles, and then hydrogen fluoride gas is introduced into the calcining furnace, and the hydrogen fluoride gas introduction flow rate is 30sccm. During this period, argon gas and hydrogen fluoride gas are continuously introduced into the calcining furnace, and the total roasting time is 40 minutes. During the roasting, the gas in the roasting furnace is discharged through the gas outlet of the roasting furnace, collected, and reserved. After the roasting is completed, the filter cake particles are cooled to room temperature and crushed to obtain aluminum ash slag. The silicon element in the aluminum ash slag is detected, and the silicon content is 1.8%.

[0048] Comparative Example 2

[0049] The present comparative example provides a method for resource utilization of aluminum ash, which differs from Example 1 in that in step 3), filter cake particles are added to a calcining furnace, and then argon gas is introduced into the calcining furnace, and the argon gas introduction flow rate is 300sccm. The calcining furnace is heated to 900°C to calcine the filter cake particles, and then hydrogen fluoride gas is introduced into the calcining furnace, and the hydrogen fluoride gas introduction flow rate is 30sccm. After the hydrogen fluoride gas is introduced for 10 minutes, hydrogen gas is introduced into the calcining furnace, and the hydrogen gas introduction flow rate is 10sccm. During this period, argon gas, hydrogen fluoride gas and hydrogen gas are continuously introduced into the calcining furnace. The total calcination time is 40 minutes. During the calcination, the gas in the calcining furnace is discharged through the gas outlet of the calcining furnace, collected and set aside. After the calcination is completed, the filter cake particles are cooled to room temperature and crushed to obtain aluminum ash slag. The silicon element in the aluminum ash slag is detected, and the silicon content is 1.4%.

[0050] Obviously, for ordinary technicians in the field, other modifications can be made based on the above embodiments, and the obvious modifications brought about by these modifications are still within the protection scope of the present invention.

Claims

1. A method for resource utilization of aluminum ash, characterized in that: The steps include: 1) crushing and sieving the secondary aluminum ash, then mixing the sieved fine material with water to obtain slurry, filtering the slurry to obtain a filter cake; 2) drying, crushing and sieving the filter cake to obtain filter cake particles; 3) adding the filter cake particles into a calcining furnace, then introducing an inert gas into the calcining furnace, heating the calcining furnace to 800-1000° C. to calcine the filter cake particles, then introducing hydrogen fluoride gas into the calcining furnace, introducing hydrogen into the calcining furnace after introducing the hydrogen fluoride gas for 8-15 minutes, stopping introducing hydrogen into the calcining furnace after introducing the hydrogen for 8-15 minutes, introducing hydrogen into the calcining furnace again after 8-15 minutes, during which time the inert gas and hydrogen fluoride gas are continuously introduced into the calcining furnace, and after the calcination is completed, cooling the filter cake particles to room temperature, crushing them, and obtaining aluminum ash slag.

2. The method for recycling aluminum ash according to claim 1, characterized in that: In step 3), the filter cake particles are added to a calcining furnace, and then argon gas is introduced into the calcining furnace, and the argon gas introduction flow rate is 280-350sccm. The calcining furnace is heated to 800-1000°C to calcine the filter cake particles, and then hydrogen fluoride gas is introduced into the calcining furnace, and the hydrogen fluoride gas introduction flow rate is 20-40sccm. After the hydrogen fluoride gas is introduced for 8-15 minutes, hydrogen gas is introduced into the calcining furnace, and the hydrogen introduction flow rate is 8-15sccm. After the hydrogen gas is introduced for 8-15 minutes, the introduction of hydrogen into the calcining furnace is stopped. After 8-15 minutes, hydrogen gas is introduced into the calcining furnace again for 8-15 minutes, and the hydrogen introduction flow rate is 8-15sccm. During this period, argon gas and hydrogen fluoride gas are continuously introduced into the calcining furnace. After the calcination is completed, the filter cake particles are cooled to room temperature and crushed to obtain aluminum ash slag.

3. The method for recycling aluminum ash according to claim 1 or 2, characterized in that: The total roasting time is 24-60h.

4. The method for resource utilization of aluminum ash according to claim 1, characterized in that: The inert gas is argon.

5. The method for recycling aluminum ash according to claim 1 or 2, characterized in that: During the roasting process, the gas in the roasting furnace is discharged through the gas outlet of the roasting furnace, collected and kept for future use.

6. The method for recycling aluminum ash according to claim 1 or 2, characterized in that: After crushing in step 1), the product is sieved through a 80-120 mesh sieve.

7. The method for recycling aluminum ash according to claim 1 or 2, characterized in that: In step 1), the fine material and water are mixed at a liquid-to-solid ratio of (6-12):

1.

8. The method for recycling aluminum ash according to claim 1 or 2, characterized in that: In step 1), the fine material and water are mixed at a liquid-to-solid ratio of 8:

1.

9. The method for recycling aluminum ash according to claim 1 or 2, characterized in that: In step 2), the drying temperature is 90-100° C. and the drying time is 4-10 hours.

10. The method for resource utilization of aluminum ash according to claim 1 or 2, characterized in that: The particle size of the filter cake particles is 1-5 mm.