Storage method for prolonging usable time of sodium silicate-bonded sand

Abstract

The invention relates to a preservation method for prolonging the usable time of sodium silicate-bonded sand, which comprises the following steps: putting mixed sodium silicate-bonded sand into a sealed container, and pumping out air in the sealed container by using a vacuum pump, so that the interior of the sealed container is preserved in a vacuum state. The usable time of the sodium silicate-bonded sand stored according to the method disclosed by the invention is obviously higher than that of the sodium silicate-bonded sand stored by the existing storage method in the production of the sodium silicate-bonded sand, and compared with the existing storage method, the method has obvious technical advantages, reduces the waste of the sodium silicate-bonded sand, saves resources, and has higher practical value and wide application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of water glass sand, and particularly relates to a storage method for increasing the usable time of water glass sand. Background Art

[0002] In the foundry industry, especially in the current environment of increasing environmental awareness, green manufacturing has become the main theme of global industrial development. The adoption of green casting processes and materials has become part of the urgent needs of the foundry industry. As an environmentally friendly casting binder, water glass has attracted much attention for its advantages and potential. However, despite the increasing maturity of water glass sand technology, its short usable time has always plagued the development of the foundry industry. Therefore, it is necessary to find a method to extend the usable time of water glass sand.

[0003] As early as 1947, the CO2 blowing hardening water glass sand process was successfully developed and received attention from the foundry industry. Through the chemical reaction of CO2 gas and water glass, water glass sand can harden quickly and have a higher compressive strength, which makes the casting process more concise, efficient and environmentally friendly. However. The current problem is that after the mixed water glass sand has been stored for a period of time, it has partially or completely hardened before the molding (core) is prepared, making it impossible to continue to use. Water glass sand is difficult to store for a long time, which limits its scope of application in foundry industry production. Therefore, how to further extend the usable time of water glass sand has become a technical problem that needs to be solved urgently. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a storage method for increasing the usable time of water glass sand, so as to solve the problem of short usable time of water glass sand at present and provide help for the flexible application of water glass sand in the foundry industry.

[0005] The present invention provides a storage method for increasing the usable time of water glass sand, comprising the following steps:

[0006] (1) Weigh water glass and raw sand and pour them into a sand mixer for mixing;

[0007] (2) putting the mixed water glass sand into a sealed container, and using a vacuum pump to extract the air in the sealed container so that the inside of the sealed container is in a vacuum state;

[0008] (3) Before use, restore the sealed container to normal pressure, take out the water glass sand in the sealed container and use it for normal casting core making.

[0009] Preferably, the water glass in step (1) includes one or more of sodium water glass, potassium water glass and lithium water glass.

[0010] Preferably, the raw sand in step (1) comprises quartz foundry sand or non-quartz foundry sand.

[0011] Preferably, the mass of water glass in step (1) is 1-10% of the mass of the original sand.

[0012] Preferably, the mixing time in step (1) is 1-10 min.

[0013] Preferably, the sealed container in step (2) includes various sealable containers such as metal, concrete, plastic film, fiber sealed container, or ordinary container, concrete, sand bucket or bag that has been sealed.

[0014] Preferably, the sealed container in step (2) is evacuated to 0.01 MPa-0.09 MPa.

[0015] Preferably, the storage time in step (2) is 1-48 hours.

[0016] The present invention puts the mixed water glass sand into a suitable sealed container, and reduces the air pressure in the container to a certain vacuum degree by vacuuming, thereby effectively removing the air and water vapor in the water glass sand, excluding various gases and humidity therein, preventing the water glass from solidifying prematurely, and extending the usable time thereof. When the water glass sand needs to be used, it is only necessary to restore the pressure in the container to a normal state, and then the water glass sand can be taken out for use.

[0017] Beneficial Effects

[0018] (1) The method of the present invention is simple and easy to implement, saving time and cost; through vacuum treatment, the storage time of water glass sand under vacuum is significantly extended, making it more suitable for the needs of actual industrial production.

[0019] (2) The usable time of the water glass sand preserved according to the method of the present invention is significantly longer than the usable time of the water glass sand preserved by the current preservation method in the production of water glass sand. Compared with the water glass sand, the method of the present invention has significant technical advantages, reduces the waste of water glass sand, saves resources, and has high practical value and broad application prospects. DETAILED DESCRIPTION

[0020] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0021] Example 1

[0022] Weigh each component separately. The original sand is 200 kg of 50-100 mesh quartz sand, 3 kg of water glass (Na2O·SiO2, modulus is 2.3, density is 1.51 g / cm 3 ), pour into a blade sand mixer and mix for 2 minutes. Put the mixed water glass sand into a sealed container and evacuate to a vacuum degree of about 0.09Mpa. After 8 hours of storage, restore the sealed container to normal pressure. Take out the water glass sand for use.

[0023] The sand core was tested according to GB / T2684-2009 testing standard. The immediate compressive strength of the sand core prepared immediately after mixing was 0.533MPa after air hardening, and the 24h compressive strength was 0.78MPa. The sand core prepared after 8 hours of storage and then taken out had an immediate compressive strength of 0.55MPa after air hardening, and the 24h compressive strength was 0.761MPa.

[0024] Example 2

[0025] Weigh each component separately. The original sand is 200 kg of quartz sand with a mesh size of 50-100, 8 kg of water glass (Na2O·SiO2, modulus of 2.3, density of 1.51 g / cm 3 ), pour into the sand mixer and mix for 2 minutes. Put the mixed water glass sand into a sealed ton bag and evacuate to a vacuum degree of about 0.09Mpa. After 8 hours, restore the bag to normal pressure. Take out the water glass sand for use.

[0026] The sand core was tested according to GB / T2684-2009 testing standard. The immediate compressive strength of the sand core prepared immediately after mixing was 0.595MPa after air hardening, and the 24h compressive strength was 1.993MPa. The sand core prepared after 8 hours of storage and then taken out had an immediate compressive strength of 0.596MPa after air hardening, and the 24h compressive strength was 2.036MPa.

[0027] Example 3

[0028] Weigh each component separately. The original sand is 200 kg of 50-100 mesh pearl sand, 3 kg of water glass (Na2O·SiO2, modulus is 2.3, density is 1.51 g / cm 3 ), pour into the sand mixer and mix for 2 minutes. Put the mixed water glass sand into a sealed container and evacuate to a vacuum degree of about 0.09Mpa. After 8 hours, restore the box to normal pressure. Take out the water glass sand for use.

[0029] The sand core was tested according to the GB / T2684-2009 test standard. The sand core prepared immediately after mixing had an immediate compressive strength of 0.812MPa after air hardening and a 24h compressive strength of 1.788MPa. The sand core prepared after 8 hours of storage and then taken out had an immediate compressive strength of 0.813MPa after air hardening and a 24h compressive strength of 1.805MPa.

[0030] Comparative Example 1

[0031] Weigh each component separately. The original sand is 200 kg of 50-100 mesh quartz sand, 3 kg of water glass (Na2O·SiO2, modulus is 2.3, density is 1.51 g / cm 3 ), pour into a blade sand mixer and mix for 2 minutes. Store the mixed water glass sand at room temperature and pressure.

[0032] The sand core was tested according to the GB / T2684-2009 test standard. The sand core prepared immediately after mixing had an immediate compressive strength of 0.533MPa after air hardening and a 24h compressive strength of 0.78MPa. The sand core prepared after 8 hours of storage and then taken out had an immediate compressive strength of ≈0MPa after air hardening and a 24h compressive strength of ≈0MPa.

[0033] Comparative Example 2

[0034] Weigh each component separately. The original sand is 200 kg of 50-100 mesh pearl sand, 3 kg of water glass (Na2O·SiO2, modulus is 2.3, density is 1.51 g / cm 3 ), pour into a blade sand mixer and mix for 2 minutes. Store the mixed water glass sand at room temperature and pressure.

[0035] The sand core was tested according to the GB / T2684-2009 test standard. The sand core sampled immediately after mixing had an immediate compressive strength of 0.812MPa after air hardening and a 24h compressive strength of 1.788MPa. The sand core prepared after 8 hours of storage and then taken out had an immediate compressive strength of ≈0MPa after air hardening and a 24h compressive strength of ≈0MPa.

Claims

1. A method for preserving water glass sand to increase its usable time, comprising the following steps: (1) Weigh water glass and raw sand and pour them into a sand mixer for mixing; (2) putting the mixed water glass sand into a sealed container, and using a vacuum pump to extract the air in the sealed container so that the inside of the sealed container is in a vacuum state; (3) Before use, restore the sealed container to normal pressure, take out the water glass sand in the sealed container and use it for normal casting, molding and core making.

2. The storage method according to claim 1, characterized in that: The water glass in step (1) includes one or more of sodium water glass, potassium water glass and lithium water glass.

3. The storage method according to claim 1, characterized in that: The raw sand in the step (1) includes quartz foundry sand or non-quartz foundry sand.

4. The storage method according to claim 1, characterized in that: The mass of water glass in step (1) is 1-10% of the mass of the original sand.

5. The storage method according to claim 1, characterized in that: The mixing time in step (1) is 1-10 min.

6. The storage method according to claim 1, characterized in that: The sealed container in step (2) includes various sealable containers such as metal, concrete, plastic film, fiber sealed containers, or ordinary containers that have been sealed, concrete, sand buckets or bags.

7. The storage method according to claim 1, characterized in that: The sealed container in step (2) is evacuated to 0.01 MPa-0.09 MPa.

8. The storage method according to claim 1, characterized in that: The storage time in step (2) is 1-48h.