Method for preparing ultralight concrete by using red mud as main raw material

Abstract

The invention relates to the technical field of ultra-light concrete, in particular to a method for preparing ultra-light concrete by using red mud as a main raw material, lightweight aggregate is prepared by metering, mixing and grinding, pelletizing and roasting red mud and coal gangue, the doping amount of the red mud is 50-70%, the doping amount of the coal gangue is 30-50%, the red-mud-based lightweight aggregate with the stacking density of 300kg / m < 3 > is selected and crushed to be below 3mm by a jaw crusher, and the red-mud-based lightweight aggregate with the stacking density of 300kg / m < 3 > is prepared into the ultra-light concrete. The red mud-based lightweight concrete is used for replacing sand and is prepared from the following components in parts by weight: 200 to 300 parts of cement, 250 to 350 parts of red mud, 250 to 350 parts of red mud-based lightweight aggregate with the size of about 10mm, 200 to 300 parts of crushed red mud-based lightweight aggregate with the size of less than 3mm and 200 to 300 parts of water. All indexes of the ultra-light concrete material are very excellent, the density grade is smaller than 1250 kg / m < 3 >, and the compressive strength is 2-15 Mpa.

Description

Technical Field

[0001] The invention relates to the technical field of ultra-light concrete, and in particular to a method for preparing ultra-light concrete using red mud as a main raw material. Background Art

[0002] Red mud is the polluting waste residue discharged when the aluminum industry extracts alumina. Generally, for every ton of alumina produced, 1.0 to 2.0 tons of red mud are produced. At present, the large amount of red mud discharged by alumina cannot be fully and effectively utilized. It can only be piled up in large areas of yards, occupying a large amount of land and causing serious pollution to the environment. About 70 million tons of red mud are produced every year in the world. The production of a large amount of red mud has caused many direct and indirect impacts on human production and life. Therefore, it is urgent to minimize the production and harm of red mud and realize multi-channel and large-scale resource utilization.

[0003] Lightweight aggregate ultra-light concrete is concrete made of lightweight aggregate. The so-called lightweight aggregate is an aggregate used to reduce the mass of concrete and improve thermal effects. Its apparent density is lower than that of ordinary aggregate. Lightweight aggregate concrete has the characteristics of light weight, high strength, thermal insulation, fire resistance, good seismic resistance, good deformation performance, low elastic modulus, and generally large shrinkage and creep. It is widely used in industrial and civil buildings and other projects. It can reduce the deadweight of the structure, save material consumption, improve the efficiency of component transportation and hoisting, reduce foundation loads, and improve the function of buildings. It is suitable for high-rise and large-span buildings. Summary of the invention

[0004] In order to solve the defects in the prior art, the present invention provides a method for preparing ultra-light concrete using red mud as the main raw material, which is specifically achieved through the following technical solutions: A method for preparing ultra-light concrete using red mud as a main raw material comprises the following steps: S1, 50%-70% dry red mud and 30%-50% coal gangue powder to produce a density of 300kg / m 3 Lightweight aggregate; S2, 300kg / m 3 The red mud-based lightweight aggregate is crushed with a jaw crusher, one part is crushed to less than 3 mm, and the other part is crushed to 10 mm; S3, select 10mm red mud-based lightweight aggregate and pre-wet it with water according to the 1h water absorption rate; S4, according to weight parts, cement 200-300 parts, red mud 250-350 parts, step S3 10mm red mud-based lightweight aggregate 250-350 parts, crushed 3mm or less red mud-based lightweight aggregate 200-300 parts, water 200-300 parts for batching; S5, prepare mixed material: add the prepared material into cement mortar mixer and mix and stir to obtain mixed material; S6, casting and molding, casting and molding in a mold; S7, vibration: Place the mold on a vibration table to shake out the air in the material, so that the mixed material is dense in the mold, and continuously fill the mold with the mixed material; S8. Remove the mold and perform curing to obtain the finished product.

[0005] In step S7, the mold needs to be vibrated three times on a vibration table.

[0006] The duration of each of the three vibrations is 20 seconds to 40 seconds.

[0007] The red mud comprises SiO2 10%-30%, Al2O 35%-35%, Fe2O 35%-40%, and GaO 10%-35% by weight.

[0008] The coal gangue powder includes SiO2 30%-40%, Al2O3 5%-45%, and Fe2O3 5%-15% by weight.

[0009] The mixed material in step S5 needs to be stirred for 5 minutes.

[0010] The technical solution of the present invention has the following advantages: Ultra-light concrete materials have excellent indicators and a density level of less than 1250kg / m 3 , compressive strength 2-15Mpa, high temperature resistance up to 1000℃. Red mud and coal gangue are fully utilized, which reduces costs and protects the environment at the same time. DETAILED DESCRIPTION

[0011] The technical solution of the present invention is described in detail below.

[0012] The present invention provides a method for preparing ultra-light concrete using red mud as a main raw material: S1, 50%-70% of dry red mud and 30%-50% of coal gangue powder are used to prepare light aggregate with a density of 300kg / m3 and a diameter of about 20mm by a burning expansion process, part of the red mud is used to replace cement, the amount of cement is reduced, and the workability of the concrete is improved, and the crushed light aggregate is used to improve the bonding force between the cementitious material and the aggregate, so as to achieve the effect of light weight and high strength. Light aggregate is used to replace stone, and the light aggregate is crushed to replace sand, so as to further reduce the bulk density of the concrete, and the partial cementitiousness of the red mud is used to reduce the amount of cement and further improve the workability of the concrete.

[0013] S2. Use a jaw crusher to crush 300kg / m3 of red mud-based lightweight aggregate, one part of which is crushed to less than 3mm and the other part is crushed to about 10mm.

[0014] S3. Select red mud-based lightweight aggregate of about 10 mm and pre-wet it with water according to the water absorption rate in 1 hour.

[0015] S4. According to weight parts, 200-300 parts of cement, 250-350 parts of red mud, 250-350 parts of 10mm red mud-based lightweight aggregate in step S3, 200-300 parts of crushed red mud-based lightweight aggregate below 3mm, and 200-300 parts of water are mixed.

[0016] S5, prepare the mixed material: add the prepared material to the cement mortar mixer and mix well, stir in the mixer for 5 minutes to obtain a mixed material; S6. Casting: Add the mixed material into a 10*10*10cm triple mold.

[0017] S7. Vibration: Place the triple mold on a vibration table and vibrate it three times to expel the air in the material. Each vibration lasts for 30 seconds to make the mixed material dense in the mold and continuously fill the triple mold with the mixed material.

[0018] S8, demoulding and curing: put the triple-mould concrete into a standard curing box for curing, and remove the mould for curing after one day to obtain the finished product.

[0019] S9, Test: Test 3 days, 7 days, 28 days strength.

[0020] Calculated by weight, red mud includes SiO2 10%-30%, Al2O3 5%-35%, Fe2O3 5%-40%, and GaO 10%-35%; coal gangue powder includes SiO2 30%-40%, Al2O3 5%-45%, and Fe2O3 5%-15%.

[0021] The following is a detailed description through specific embodiments.

[0022] Example 1 S1. 50%-70% dry red mud and 30%-50% coal gangue powder are used to produce lightweight aggregate with a density grade of 300kg / m3.

[0023] S2. The red mud-based lightweight aggregate is crushed by a jaw crusher, one part is crushed to less than 3 mm, and the other part is crushed to about 10 mm.

[0024] S3. Select red mud-based lightweight aggregate of about 10 mm and pre-wet it with water according to the water absorption rate in 1 hour.

[0025] S4. According to weight parts, 200 parts of cement, 250 parts of red mud, 250 parts of 10 mm red mud-based lightweight aggregate in step S3, 200 parts of crushed red mud-based lightweight aggregate below 3 mm, and 200 parts of water are mixed.

[0026] S5, prepare the mixed material: add the prepared material to the cement mortar mixer and mix well, stir in the mixer for 5 minutes to obtain a mixed material; S6. Casting: Add the mixed material into a 10*10*10cm triple mold.

[0027] S7. Vibration: Place the triple mold on a vibration table and vibrate it three times to expel the air in the material. Each vibration lasts for 25 seconds to make the mixed material dense in the mold and continuously fill the triple mold with the mixed material.

[0028] S8. Formwork removal and curing: Place the triple-form concrete in a standard curing box for curing, and remove the formwork for curing after one day.

[0029] S9, Test: Test 3 days, 7 days, 28 days strength.

[0030] Example 2 S1, 50%-70% dry red mud and 30%-50% coal gangue powder to produce a density of 300kg / m 3 of lightweight aggregate.

[0031] S2. The red mud-based lightweight aggregate is crushed by a jaw crusher, one part is crushed to less than 3 mm, and the other part is crushed to about 10 mm.

[0032] S3. Select red mud-based lightweight aggregate of about 10 mm and pre-wet it with water according to the water absorption rate in 1 hour.

[0033] S4. According to weight parts, 200 parts of cement, 300 parts of red mud, 280 parts of 10 mm red mud-based lightweight aggregate in step S3, 240 parts of crushed red mud-based lightweight aggregate below 3 mm, and 230 parts of water are mixed.

[0034] S5, prepare the mixed material: add the prepared material to the cement mortar mixer and mix well, stir in the mixer for 5 minutes to obtain a mixed material; S6. Casting: Add the mixed material into a 10*10*10cm triple mold.

[0035] S7. Vibration: Place the triple mold on a vibration table and vibrate it three times to expel the air in the material. Each vibration lasts for 20 seconds to make the mixed material dense in the mold and continuously fill the triple mold with the mixed material.

[0036] S8. Formwork removal and curing: Place the triple-form concrete in a standard curing box for curing, and remove the formwork for curing after one day.

[0037] S9, Test: Test 3 days, 7 days, 28 days strength.

[0038] Example 3 S1, 50%-70% dry red mud and 30%-50% coal gangue powder to produce a density of 300kg / m 3 of lightweight aggregate.

[0039] S2. The red mud-based lightweight aggregate is crushed by a jaw crusher, one part is crushed to less than 3 mm, and the other part is crushed to about 10 mm.

[0040] S3. Select red mud-based lightweight aggregate of about 10 mm and pre-wet it with water according to the water absorption rate in 1 hour.

[0041] S4. According to weight parts, 250 parts of cement, 300 parts of red mud, 280 parts of 10 mm red mud-based lightweight aggregate in step S3, 250 parts of crushed red mud-based lightweight aggregate below 3 mm, and 250 parts of water are mixed.

[0042] S5, prepare the mixed material: add the prepared material to the cement mortar mixer and mix well, stir in the mixer for 5 minutes to obtain a mixed material; S6. Casting: Add the mixed material into a 10*10*10cm triple mold.

[0043] S7. Vibration: Place the triple mold on a vibration table and vibrate it three times to expel the air in the material. Each vibration lasts 40 seconds to make the mixed material dense in the mold and continuously fill the triple mold with the mixed material.

[0044] S8. Formwork removal and curing: Place the triple-form concrete in a standard curing box for curing, and remove the formwork for curing after one day.

[0045] S9, Test: Test 3 days, 7 days, 28 days strength.

[0046] Example 4 S1, 50%-70% dry red mud and 30%-50% coal gangue powder to produce a density of 300kg / m 3 of lightweight aggregate.

[0047] S2. The red mud-based lightweight aggregate is crushed by a jaw crusher, one part is crushed to less than 3 mm, and the other part is crushed to about 10 mm.

[0048] S3. Select red mud-based lightweight aggregate of about 10 mm and pre-wet it with water according to the water absorption rate in 1 hour.

[0049] S4. According to weight parts, 280 parts of cement, 300 parts of red mud, 250 parts of 10mm red mud-based lightweight aggregate in step S3, 270 parts of crushed red mud-based lightweight aggregate below 3mm, and 260 parts of water are mixed.

[0050] S5, prepare the mixed material: add the prepared material to the cement mortar mixer and mix well, stir in the mixer for 5 minutes to obtain a mixed material; S6. Casting: Add the mixed material into a 10*10*10cm triple mold.

[0051] S7. Vibration: Place the triple mold on a vibration table and vibrate it three times to expel the air in the material. Each vibration lasts for 25 seconds to make the mixed material dense in the mold and continuously fill the triple mold with the mixed material.

[0052] S8. Formwork removal and curing: Place the triple-form concrete in a standard curing box for curing, and remove the formwork for curing after one day.

[0053] S9, Test: Test 3 days, 7 days, 28 days strength.

[0054] Example 5 S1, 50%-70% dry red mud and 30%-50% coal gangue powder to produce a density of 300kg / m 3 of lightweight aggregate.

[0055] S2. The red mud-based lightweight aggregate is crushed by a jaw crusher, one part is crushed to less than 3 mm, and the other part is crushed to about 10 mm.

[0056] S3. Select red mud-based lightweight aggregate of about 10 mm and pre-wet it with water according to the water absorption rate in 1 hour.

[0057] S4. According to weight parts, 300 parts of cement, 330 parts of red mud, 320 parts of 10 mm red mud-based lightweight aggregate in step S3, 300 parts of crushed red mud-based lightweight aggregate below 3 mm, and 300 parts of water are mixed.

[0058] S5, prepare the mixed material: add the prepared material to the cement mortar mixer and mix well, stir in the mixer for 5 minutes to obtain a mixed material; S6. Casting: Add the mixed material into a 10*10*10cm triple mold.

[0059] S7. Vibration: Place the triple mold on a vibration table and vibrate it three times to expel the air in the material. Each vibration lasts for 30 seconds to make the mixed material dense in the mold and continuously fill the triple mold with the mixed material.

[0060] S8. Formwork removal and curing: Place the triple-form concrete in a standard curing box for curing, and remove the formwork for curing after one day.

[0061] S9, Test: Test 3 days, 7 days, 28 days strength.

[0062] Example 6 S1, 50%-70% dry red mud and 30%-50% coal gangue powder to produce a density of 300kg / m 3 of lightweight aggregate.

[0063] S2. The red mud-based lightweight aggregate is crushed by a jaw crusher, one part is crushed to less than 3 mm, and the other part is crushed to about 10 mm.

[0064] S3. Select red mud-based lightweight aggregate of about 10 mm and pre-wet it with water according to the water absorption rate in 1 hour.

[0065] S4. According to weight parts, 280 parts of cement, 350 parts of red mud, 350 parts of 10 mm red mud-based lightweight aggregate in step S3, 300 parts of crushed red mud-based lightweight aggregate below 3 mm, and 300 parts of water are mixed.

[0066] S5, prepare the mixed material: add the prepared material to the cement mortar mixer and mix well, stir in the mixer for 5 minutes to obtain a mixed material; S6. Casting: Add the mixed material into a 10*10*10cm triple mold.

[0067] S7. Vibration: Place the triple mold on a vibration table and vibrate it three times to expel the air in the material. Each vibration lasts for 25 seconds to make the mixed material dense in the mold and continuously fill the triple mold with the mixed material.

[0068] S8. Formwork removal and curing: Place the triple-form concrete in a standard curing box for curing, and remove the formwork for curing after one day.

[0069] S9. Test: Test the compressive strength for 3 days, 7 days and 28 days.

[0070] Table 1 Compressive strength test results

[0071] Table 2 Test results of other items

[0072] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A method for preparing ultra-light concrete using red mud as the main raw material, characterized in that: The following steps are involved: S1, 50%-70% dry red mud and 30%-50% coal gangue powder to produce a density of 300kg / m 3 Lightweight aggregate; S2, 300kg / m 3 The red mud-based lightweight aggregate is crushed by jaw crusher, one part is crushed to less than 3mm, and the other part is crushed to 10mm; S3, select 10mm red mud-based lightweight aggregate and pre-wet it with water according to the 1h water absorption rate; S4, according to weight parts, cement 200-300 parts, red mud 250-350 parts, step S3 10mm red mud-based lightweight aggregate 250-350 parts, crushed 3mm or less red mud-based lightweight aggregate 200-300 parts, water 200-300 parts for batching; S5, prepare mixed material: add the prepared material into cement mortar mixer and mix and stir to obtain mixed material; S6, casting and molding, casting and molding in a mold; S7, vibration: Place the mold on a vibration table to shake out the air in the material, so that the mixed material is dense in the mold, and continuously fill the mold with the mixed material; S8. Remove the mold and perform curing to obtain the finished product.

2. The method for preparing ultra-light concrete using red mud as the main raw material according to claim 1, characterized in that: In step S7, the mold needs to be vibrated three times on a vibration table.

3. The method for preparing ultralight concrete using red mud as the main raw material according to claim 2, characterized in that: The duration of each of the three vibrations is 20 seconds to 40 seconds.

4. The method for preparing ultralight concrete using red mud as the main raw material according to claim 1, characterized in that: The red mud comprises SiO2 10%-30%, Al2O 35%-35%, Fe2O 35%-40%, and GaO 10%-35% by weight.

5. The method for preparing ultra-light concrete using red mud as the main raw material according to claim 1, characterized in that: The coal gangue powder includes SiO2 30%-40%, Al2O3 5%-45%, and Fe2O3 5%-15% by weight.

6. The method for preparing ultralight concrete using red mud as the main raw material according to claim 1, characterized in that: The mixed material in step S5 needs to be stirred for 5 minutes.

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