Low-carbon aggregate based on solid waste and preparation method thereof

Abstract

The application provides a kind of low-carbon aggregate based on solid waste and a preparation method, and belongs to the technical field of solid waste resource utilization, the low-carbon aggregate includes a solid waste layer and a stable layer and a pressure-bearing layer wrapped in the solid waste layer from inside to outside;The application designs the low-carbon aggregate into three layers, and strictly controls the thickness of each layer;The innermost layer is a solid waste layer, which uses a small amount of materials with hydration activity to preliminarily fix the waste slag;Then use steel slag, slag, desulfurization gypsum, etc.to prepare a stable layer with high density, which tightly wraps the waste slag, so that harmful elements cannot leach out;Finally, use silica fume, cement, steel slag, slag, desulfurization gypsum, etc.to prepare a pressure-bearing layer with high strength to provide strength for the low-carbon aggregate.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of solid waste resource utilization, and particularly relates to a low-carbon aggregate based on solid waste and a preparation method. BACKGROUND

[0002] The utilization rate of difficult-to-utilize solid waste such as waste incineration fly ash, slag, phosphogypsum, tailings powder and lithium slag is low, and most of them are stored and landfilled, which will seriously pollute groundwater resources and the surrounding environment. At the same time, the traditional method of mountain blasting and stone preparation for aggregate is difficult to continue, which also leads to a gradual shortage of high-quality aggregate in the market, and the engineering quality is difficult to guarantee. SUMMARY

[0003] The application provides a low-carbon aggregate based on solid waste and a preparation method, which seals the waste slag in the aggregate in the form of a high-density low-carbon cementing material, realizes the disposal of industrial waste, and improves the quality of the aggregate due to the high strength and good durability of the low-carbon cementing material, thereby achieving the purpose of waste treatment.

[0004] To achieve the above-mentioned purpose, the technical scheme adopted by the application is as follows: a low-carbon aggregate based on solid waste is provided, which comprises a solid waste layer and a stable layer and a pressure-bearing layer which are sequentially wrapped from inside to outside of the solid waste layer; according to the particle size range of the low-carbon aggregate, the thicknesses of the solid waste layer, the stable layer and the pressure-bearing layer are determined as follows:

[0005] When the particle size range of the low-carbon aggregate is between 5.0mm and 10.0mm, the diameter of the solid waste layer is 0.3mm to 2.36mm, the thickness of the stable layer is 0.3mm to 2.36mm, and the thickness of the pressure-bearing layer is 1.18mm to 3.3mm;

[0006] When the particle size range of the low-carbon aggregate is between 10.0mm and 20.0mm, the diameter of the solid waste layer is 0.6mm to 4.5mm, the thickness of the stable layer is 0.6mm to 4.5mm, and the thickness of the pressure-bearing layer is 2.36mm to 8.0mm;

[0007] When the particle size range of the low-carbon aggregate is between 20.0mm and 40.0mm, the diameter of the solid waste layer is 1.18mm to 9.5mm, the thickness of the stable layer is 2.36mm to 8.0mm, and the thickness of the pressure-bearing layer is 4.5mm to 12.5mm.

[0008] In combination with the first aspect, in an implementable manner, the solid waste layer comprises, in terms of mass percentage, 10% to 25% of waste incineration fly ash, 13% to 30% of slag, 22% to 37% of red mud, 10% to 20% of carbide slag, and 10% to 26% of other components;

[0009] The other components are composed of one or more of phosphogypsum, tailings powder, stone powder, dust removal ash, phosphorus slag, mercury slag, chromium slag, boron slag, lithium slag in any proportion;

[0010] The stable layer comprises, in percentage by mass: 20-35% of steel slag, 30-55% of slag, 5-15% of desulfurization gypsum, 10-25% of fly ash and 0.5-1.5% of Na2CO3.

[0011] The pressure-bearing layer comprises, in percentage by mass: 15-25% of silica fume, 10-25% of steel slag, 30-50% of slag, 5-15% of desulfurization gypsum and 5-15% of cement.

[0012] In the second aspect, the application also provides a preparation method of the low-carbon aggregate based on solid waste.

[0013] Step one, preparation of the solid waste layer:

[0014] After the powder of the solid waste layer is uniformly mixed in proportion, X kg of the powder is weighed and arranged in a disc granulator, the disc is started, and the mixed powder is sprayed with water in an amount of 0.27X-0.32X until the spraying is completed; particles not meeting the target particle size are screened out, and the mass m1 of the low-carbon aggregate primary product a is obtained.

[0015] Step two, wrapping the stable layer on the surface of the low-carbon aggregate primary product a:

[0016] After the excess stable layer powder is uniformly mixed in proportion, it is placed in a first hopper for standby;

[0017] The low-carbon aggregate primary product a is placed in the disc of the disc granulator, the included angle θ between the disc and the horizontal plane is adjusted to 38-43°, the disc granulator is started, and the first hopper is also started, so that the stable layer powder in the first hopper falls into the disc in batches, the mass of the stable layer powder falling into the disc each time is controlled to be 0.15m1-0.25m1, and after each batch of the stable layer powder is discharged, a sprayer is started, and the amount of water sprayed each time is 0.23-0.28 of the mass of the stable layer powder falling into the disc.

[0018] Then the first hopper is started again to discharge the stable layer powder, and the above steps are repeated until more than 80% of the particles reach the diameter of the stable layer, the disc granulator is kept rotating for 5-8 min, and then the disc granulator is stopped; particles not meeting the target particle size are screened out, and the low-carbon aggregate primary product b is obtained, and the mass m2 of the low-carbon aggregate primary product b is obtained.

[0019] Step three, wrapping the pressure-bearing layer on the surface of the low-carbon aggregate primary product b:

[0020] After the excess pressure-bearing layer powder is mixed and stirred uniformly in proportion, it is placed in the second hopper for standby;

[0021] The low-carbon aggregate primary product b is placed in the rotating disc of the disc granulator, the included angle θ between the rotating disc and the horizontal plane is adjusted to 30°-36°, the disc granulator is started, and the second hopper is started at the same time, so that the pressure-bearing layer powder in the second hopper is dropped into the rotating disc in batches,

[0022] Then the second hopper is started again to discharge, and the above steps are repeated until more than 80% of the particles reach the diameter of the pressure-bearing layer, and then the disc granulator is kept rotating for 6-10 min before being turned off. The particles that do not meet the target particle size are screened out, and the low-carbon aggregate primary product c is obtained.

[0023] Step four, after the low-carbon aggregate primary product c is cured in the curing box, it is placed in the autoclave for autoclave curing, and then the low-carbon aggregate primary product d is obtained after the pressure in the autoclave is reduced to normal pressure and the temperature is reduced to normal temperature.

[0024] Step five, the low-carbon aggregate primary product d is placed in the rapid carbonization box for carbonization, and the low-carbon aggregate finished product is obtained.

[0025] In combination with the second aspect, in an implementable manner, in step one, the rotating speed of the disc granulator is controlled to be ;

[0026] In the formula, n is the rotating speed, in r / min;

[0027] θ is the included angle between the rotating disc and the horizontal plane, the included angle is the inclination angle, and the value is controlled to be 40°-45°;

[0028] d is the diameter of the rotating disc, and the value is controlled to be 0.5 m-8.5 m.

[0029] In combination with the second aspect, in an implementable manner, in step one, after the water is sprayed, the disc is kept rotating and observed, and when more than 80% of the particles reach the diameter of the solid waste layer, the disc granulator is kept rotating for 3-5 min before being turned off.

[0030] In combination with the second aspect, in an implementable manner, in step two, the included angle θ between the rotating disc and the horizontal plane is adjusted to 38°-43°, and the rotating speed is calculated according to the rotating speed control formula.

[0031] In combination with the second aspect, in an implementable manner, in step two, the mass of the stabilizing layer powder dropped into the disc each time is controlled to be 0.15 m1-0.25 m1, and after each time of discharging, the sprayer is started, and the water sprayed each time is 0.23-0.28 of the mass of the powder dropped into the disc.

[0032] With reference to the second aspect, in an implementable mode, in step three, the included angle θ between the rotating disc and the horizontal plane is adjusted to 30°-36°, and the rotating speed is calculated according to the rotating speed control formula; the mass of the pressure-bearing layer powder falling each time is controlled to 0.20 m2-0.30 m2, and after each time of discharging is completed, the sprayer is started, and the water spraying amount each time is 0.19-0.24 of the mass of the pressure-bearing layer powder falling into the rotating disc.

[0033] With reference to the second aspect, in an implementable mode, in step four, after curing in the curing box under the condition of a temperature of 20℃±1℃ and a humidity of ≥90% for 16h-24h, the low-carbon aggregate is placed in the autoclave for autoclave curing under a pressure of 2.0Mpa-3.5Mpa and a temperature of 170℃-200℃ for 2h-5h, and after the autoclave curing is completed, the exhaust valve is opened to exhaust.

[0034] With reference to the second aspect, in an implementable mode, in step five, the low-carbon aggregate preliminary product d is carbonized under the condition of a temperature of 20℃±5℃, a carbon dioxide concentration of 0.85-1.50%, and a relative humidity of 65%-75% for 72h-144h to obtain a low-carbon aggregate finished product.

[0035] The low-carbon aggregate based on solid waste and the preparation method have the following beneficial effects compared with the prior art:

[0036] (1) The low-carbon aggregate is designed as three layers, and the thickness of each layer is strictly controlled; the innermost layer is a solid waste layer, a small amount of material with hydration activity is used to preliminarily fix the waste slag; then steel slag, slag, desulfurization gypsum, etc. are used to prepare a stable layer with high compactness, which tightly wraps the waste slag inside, so that harmful elements cannot be leached out; finally, silica fume, cement, steel slag, slag, desulfurization gypsum, etc. are used to prepare a pressure-bearing layer with high strength, which provides strength for the aggregate.

[0037] (2) The solid waste accounts for about 92.5%-97.5%, which not only realizes the harmless treatment of waste slag, but also ensures the strength of the aggregate; at the same time, the concept of treating waste with waste is realized, which is also in line with the national low-carbon development strategy.

[0038] (3) The stable layer uses steel slag, slag, desulfurization gypsum to provide certain strength, uses the secondary hydration characteristics of fly ash to make the stable layer have higher compactness, and at the same time, Na2CO3 is added, which can react with Ca(OH)2 generated by hydration to generate NaOH, continuously providing an alkaline environment, so that hydration continuously occurs, the compactness continuously increases, and then the industrial waste slag is tightly wrapped inside the stable layer, and harmful ions such as heavy metal ions are not easily leached out, realizing the harmless treatment of industrial waste slag.

[0039] (4) The particle size of the aggregate has a great relationship with the rotation speed and the inclination angle of the disc granulator, and according to the target particle size of the low-carbon aggregate, the angle between the rotating disc and the horizontal plane and the rotation speed are adjusted, so that the proportion of the target particle size aggregate can be increased, the preparation efficiency of the aggregate can be improved, and the waste of the material can be reduced; after the target particle size is reached, the rotating disc continues to rotate for a certain period of time, so that the compactness and the strength of the aggregate can be improved.

[0040] (5) The aggregate prepared by using the disc granulator has good particle shape and does not contain stone powder, the occurrence of alkali-aggregate reaction is avoided through carbonization, and the quality of the aggregate is improved; meanwhile, the strength of the aggregate is quickly improved by using the autoclave, so that the preparation process of the low-carbon aggregate is simple and fast.

[0041] In summary, the low-carbon aggregate is prepared by using various bulk solid wastes, the low-carbon cementitious material with high compactness is used to encapsulate the waste slag in the aggregate in the form of encapsulation, so that the industrial waste is accommodated, meanwhile, due to the characteristics of high strength and good durability of the low-carbon cementitious material, the quality of the aggregate can be greatly improved, the purpose of treating waste with waste is achieved, and the low-carbon development concept is met; the harmless treatment of the industrial solid waste is realized by using the method of treating waste with waste, and the problem of shortage of high-quality aggregate in the current market is solved. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 A preparation process flow chart of the low-carbon aggregate based on solid waste is provided for the embodiment of the present application;

[0043] Figure 2 A structure schematic diagram of the low-carbon aggregate with a particle size range of 5.0mm-10.0mm is provided for the embodiment of the present application;

[0044] Figure 3 A structure schematic diagram of the low-carbon aggregate with a particle size range of 10.0mm-20.0mm is provided for the embodiment of the present application;

[0045] Figure 4 A structure schematic diagram of the low-carbon aggregate with a particle size range of 20.0mm-40.0mm is provided for the embodiment of the present application;

[0046] MARKS OF THE DRAWINGS:

[0047] 1, solid waste layer; 2, stable layer; 3, pressure-bearing layer. DETAILED DESCRIPTION

[0048] In order to make the technical problems, technical solutions and beneficial effects of the present application clearer, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0049] The low-carbon aggregate based on solid waste and the preparation method provided by the present application will be described.

[0050] Example 1, please refer to Figure 1 and Figure 2 :

[0051] A low-carbon aggregate based on solid waste, the solid waste layer 1 includes, by mass percentage: 16% of waste incineration fly ash, 22% of slag, 35% of red mud, 12% of carbide slag, and 15% of other components, the other components consisting of 25% of tailings powder, 20% of stone powder, 10% of boron slag, and 45% of lithium slag; the stabilizing layer 2 includes, by mass percentage: 25% of steel slag, 46% of slag, 11.3% of desulfurization gypsum, 17% of fly ash, and 0.7% of Na2CO3; the pressure-bearing layer 3 includes, by mass percentage: 16% of silica fume, 19% of steel slag, 45% of slag, 8% of desulfurization gypsum, and 12% of cement.

[0052] The low-carbon aggregate prepared in this embodiment has a particle size of 5.0mm-10.0mm, the solid waste layer 1 has a diameter of 0.3mm-2.36mm, the stabilizing layer 2 has a thickness of 0.3mm-2.36mm, and the pressure-bearing layer 3 has a thickness of 1.18mm-3.3mm.

[0053] The preparation method includes the following steps:

[0054] Step 1, preparation of the solid waste layer 1: set the angle θ between the rotating disc and the horizontal plane to 45°, measure the diameter of the rotating disc to be 2.5m, calculate the rotating speed range of the disc granulator to be 10r / min-14r / min, and select the rotating speed of 12r / min for granulation. Weigh 20kg of solid waste layer powder and uniformly arrange it in the disc granulator, start the rotating disc, and at the same time use a sprayer to spray the powder, with a water consumption of 5.6kg.

[0055] After the specified amount of water is sprayed and more than 80% of the particles have a particle size of 0.3mm-2.36mm, continue to rotate the disc for 3min, turn off the disc granulator, sieve out the particles that do not meet the target particle size, and obtain the low-carbon aggregate primary product a, which weighs 24.7kg.

[0056] Step 2, wrapping the stabilizing layer 2: mix the excess stabilizing layer powder in proportion, stir uniformly, and place it in the first hopper for standby. Place the low-carbon aggregate primary product a in the rotating disc of the disc granulator, adjust the angle θ between the rotating disc and the horizontal plane to 40°, the diameter of the rotating disc is 2.5m, calculate the rotating speed range of the disc granulator to be 8r / min-13r / min, and select the rotating speed of 9r / min for granulation.

[0057] Start the disc granulator, and at the same time, start the first hopper to make the stable layer powder in the first hopper fall into the rotating disc in batches. The mass of the stable layer powder falling into the rotating disc each time is controlled to be 4.5 kg. After each time of feeding is completed, start the sprayer. The water quantity sprayed each time is 1.3 kg of the mass of the powder falling into the rotating disc.

[0058] Then, open the first hopper again to feed, and repeat the above steps until the thickness of the stable layer of more than 80% reaches 0.3 mm to 2.36 mm. Continue to keep the rotating disc rotating for 6 min, and then stop the disc granulator. Screen out the particles not meeting the target particle size to obtain low-carbon aggregate primary product b. The mass of the low-carbon aggregate primary product b is 183.1 kg.

[0059] Step three, wrapping the pressure-bearing layer 3: after the excess pressure-bearing layer powder is uniformly mixed and stirred in proportion, place the pressure-bearing layer powder in the second hopper for standby.

[0060] Place the low-carbon aggregate primary product b in the rotating disc of the disc granulator. The included angle θ between the rotating disc and the horizontal plane is adjusted to 35°. The diameter of the rotating disc is 2.5 m. The rotating speed range of the disc granulator is calculated to be 7 r / min to 11 r / min. The rotating speed of 8 r / min is selected for granulation.

[0061] Start the disc granulator, and at the same time, start the second hopper to make the pressure-bearing layer powder in the second hopper fall into the disc in batches. The mass of the pressure-bearing layer powder falling into the disc each time is controlled to be 42.1 kg. After each time of feeding is completed, start the sprayer. The water quantity sprayed each time is 9.3 kg of the mass falling into the rotating disc.

[0062] Then, open the second hopper again to feed, and repeat the above steps until the thickness of the pressure-bearing layer of more than 80% reaches 1.18 mm to 3.3 mm. Continue to keep the rotating disc rotating for 8 min, and then stop the disc granulator. Screen out the particles not meeting the target particle size to obtain low-carbon aggregate primary product c.

[0063] Step four: place the low-carbon aggregate primary product c in a curing box, and after curing for 17 h under the condition of a temperature of 20℃±1℃ and a humidity of ≥90%, place the low-carbon aggregate primary product c in a pressure steaming kettle to perform autoclaved curing for 3 h under the condition of 2.3 Mpa and 175℃. After the autoclaved curing is completed, open the exhaust valve. After the pressure in the kettle decreases to normal pressure and the temperature decreases to normal temperature, take out the aggregate to obtain low-carbon aggregate primary product d.

[0064] Step five: place the low-carbon aggregate primary product d in a rapid carbonization box to carbonize for 84 h under the condition of a temperature of 20℃±5℃, a carbon dioxide concentration of 0.95%, and a relative humidity of 68%, to obtain low-carbon aggregate finished product.

[0065] Example two, please refer to Figure 1 and Figure 3 :

[0066] A kind of low-carbon aggregate based on solid waste, solid waste layer 1 includes by mass percentage: garbage incineration fly ash 20%, slag 25%, red mud 26%, carbide slag 17%, and other components 12%, other components are composed of phosphogypsum 15%, tailings micro powder 15%, dust 25%, chromium slag 10%, lithium slag 35%; Stable layer 2 includes by mass percentage: steel slag 30%, slag 43%, desulfurization gypsum 13.6%, fly ash 12.2% and Na2CO3 1.2%; Pressure-bearing layer 3 includes by mass percentage: silica fume 21%, steel slag 15%, slag 47%, desulfurization gypsum 6%, cement 11%.

[0067] The aggregate prepared in the embodiment is 10.0mm-20.0mm aggregate, the solid waste layer 1 is 0.6mm-4.5mm in diameter, the stable layer 2 is 0.6mm-4.5mm in thickness, and the pressure-bearing layer 3 is 2.36mm-8.0mm in thickness.

[0068] The preparation method includes the following steps:

[0069] Step one, preparation of solid waste layer 1: the angle θ between the rotating disc and the horizontal plane is set to 42°, the rotating disc diameter is measured to be 4.0m, and the rotating speed range of the disc granulator is calculated to be 7r / min-11r / min, and the rotating speed of 8r / min is selected for granulation.

[0070] 10kg of solid waste layer powder is weighed and uniformly arranged in the disc granulator, the rotating disc is started, and the powder is sprayed with a water amount of 3.0kg using a sprayer.

[0071] After the specified water amount is sprayed and more than 80% of the particles reach a particle size of 0.6mm-4.5mm, the rotating disc is continuously kept rotating for 4min, the disc granulator is turned off, the particles not meeting the target particle size are screened out, and the low-carbon aggregate primary product a is obtained, and the mass of the low-carbon aggregate primary product a is weighed to be 12.2kg.

[0072] Step two, wrapping stable layer 2: after the excess stable layer powder is uniformly mixed and stirred according to the proportion, it is placed in the first hopper for standby.

[0073] The low-carbon aggregate primary product a is placed in the rotating disc of the disc granulator, the angle θ between the rotating disc and the horizontal plane is adjusted to 38°, the rotating disc diameter is 4.0m, the rotating speed range of the disc granulator is calculated to be 6r / min-10r / min, and the rotating speed of 7r / min is selected for granulation.

[0074] The disc granulator is started, and the stable layer powder in the first hopper is allowed to fall into the disc in batches, with the mass of the stable layer powder falling into the disc being controlled to be 2.1kg each time, the sprayer is started after each time of discharging, and the water amount sprayed each time is 0.55kg of the mass of the powder falling into the disc.

[0075] Then open the first hopper again, repeat the above steps until the stable layer thickness of more than 80% reaches 0.6mm-4.5mm, continue to keep the disc rotating for 5min and then close the disc granulator.

[0076] Screen out the particles not meeting the target particle size to obtain the low-carbon aggregate primary product b, and weigh to obtain the mass of the low-carbon aggregate primary product b as 97.6kg.

[0077] Step three, wrapping the pressure-bearing layer 3: after the excess pressure-bearing layer powder is mixed and stirred uniformly in proportion, it is placed in the second hopper for standby.

[0078] The low-carbon aggregate primary product b is placed in the rotating disc of the disc granulator. The included angle θ between the rotating disc and the horizontal plane is adjusted to 32°, the diameter of the rotating disc is 4.0m, and the calculated rotating speed range of the disc granulator is 6r / min-9r / min, and the rotating speed of 7r / min is selected for granulation.

[0079] The disc granulator is started, and the second hopper is started at the same time, so that the pressure-bearing layer powder in the second hopper falls into the rotating disc in batches, and the mass of the pressure-bearing layer powder falling into the rotating disc each time is controlled at 25.4kg. After each time of feeding is completed, the sprayer is started, and the water quantity sprayed each time is 5.3kg.

[0080] Then the second hopper is started again, and the above steps are repeated until the thickness of the pressure-bearing layer of more than 80% reaches 2.36mm-8.0mm, and the disc granulator is closed after the rotating disc continues to rotate for 9min. Screen out the particles not meeting the target particle size to obtain the low-carbon aggregate primary product c.

[0081] Step four: after the low-carbon aggregate primary product c is placed in the curing box under the conditions of temperature 20℃±1℃ and humidity ≥90% for 20h, it is placed in the autoclave for autoclave curing at 2.8Mpa and 186℃ for 4h. After the autoclave curing is completed, the exhaust valve is opened, and after the pressure in the autoclave decreases to normal pressure and the temperature decreases to normal temperature, the aggregate is taken out to obtain the low-carbon aggregate primary product d.

[0082] Step five: the low-carbon aggregate primary product d is placed in the rapid carbonization box under the conditions of temperature 20℃±5℃, carbon dioxide concentration 1.20% and relative humidity 71% for carbonization for 96h. The low-carbon aggregate finished product is obtained.

[0083] Example three, please refer to Figure 1 and Figure 4 :

[0084] A kind of low-carbon aggregate based on solid waste, solid waste layer 1 includes by mass percentage: garbage incineration fly ash 14%, slag 23%, red mud 29%, carbide slag 13%, and other components 21%, other components are composed of stone powder 27%, dust ash 15%, mercury slag 11%, boron slag 27%, lithium slag 20%;Stable layer 2 includes by mass percentage: steel slag 23%, slag 52%, desulfurization gypsum 9.5%, fly ash 14.2% and Na2CO3 1.3%;Pressure-bearing layer 3 includes by mass percentage: silica fume 25%, steel slag 12%, slag 44%, desulfurization gypsum 11%, cement 8%.

[0085] The aggregate prepared in the embodiment is 10.0mm-20.0mm aggregate, the diameter of solid waste layer 1 is 0.6mm-4.5mm, the thickness of stable layer 2 is 0.6mm-4.5mm, and the thickness of pressure-bearing layer 3 is 2.36mm-8.0mm.

[0086] The preparation method includes the following steps:

[0087] Step one, preparation of solid waste layer 1: the angle θ between the rotating disc and the horizontal plane is 45°, the diameter of the rotating disc is 2.0m, the rotating speed range of the disc granulator is calculated to be 11r / min-16r / min, and the rotating speed of 15r / min is selected for granulation.

[0088] 15kg of solid waste layer powder is uniformly arranged in the disc granulator, the rotating disc is started, and the powder is sprayed using a sprayer with a water amount of 4.5kg. After the specified water amount is sprayed and more than 80% of the particles reach a particle size of 0.6mm-4.5mm, the rotating disc is kept rotating for 5min, the disc granulator is turned off, and the particles not meeting the target particle size are screened out to obtain low-carbon aggregate primary product a, and the mass of the low-carbon aggregate primary product a is 18.0kg.

[0089] Step two, wrapping stable layer 2: after the excess stable layer powder is mixed and stirred uniformly according to the proportion, it is placed in the first hopper for standby. The low-carbon aggregate primary product a is placed in the rotating disc of the disc granulator, the angle θ between the rotating disc and the horizontal plane is adjusted to 39°, the diameter of the rotating disc is 2.0m, and the rotating speed range of the disc granulator is calculated to be 9r / min-14r / min, and the rotating speed of 10r / min is selected for granulation.

[0090] The disc granulator is started, and the stable layer powder in the first hopper is dropped into the disc in batches, with the mass of the stable layer powder dropped each time controlled at 3.1kg. After each batch is dropped, the sprayer is started, and the water amount sprayed each time is 0.74kg of the mass of the powder dropped into the rotating disc.

[0091] Then open the discharge hopper again, repeat the above steps until the thickness of the stable layer of more than 80% reaches 0.6mm-4.5mm, continue to keep the rotating disc rotating for 8min and then close the disc granulator. Screen out the particles that do not meet the target particle size to obtain low-carbon aggregate primary product b, and weigh to obtain the mass of low-carbon aggregate primary product b as 142.6kg.

[0092] Step three, wrapping the pressure-bearing layer 3: After mixing and stirring the excess pressure-bearing layer powder in proportion, place it in the second hopper for standby.

[0093] Place the low-carbon aggregate primary product b in the rotating disc of the disc granulator. Adjust the angle θ between the rotating disc and the horizontal plane to 30°, and the diameter of the rotating disc is 2.0m. Calculate the rotating speed range of the rotating disc granulator as 7r / min-11r / min, and select the rotating speed of 8r / min for granulation.

[0094] Open the disc granulator and at the same time open the second hopper, so that the pressure-bearing layer powder in the second hopper falls into the rotating disc in batches. The mass of the pressure-bearing layer powder falling into the rotating disc each time is controlled at 41.4kg. After each batch of pressure-bearing layer powder is discharged, open the sprayer, and the amount of water sprayed each time is 8.7kg.

[0095] Then open the hopper again, repeat the above steps until the thickness of the pressure-bearing layer of more than 80% reaches 2.36mm-8.0mm, continue to keep the rotating disc rotating for 10min and then close the disc granulator. Screen out the particles that do not meet the target particle size to obtain low-carbon aggregate primary product c.

[0096] Step four: Place the low-carbon aggregate primary product c in the curing box, and after curing at a temperature of 20℃±1℃ and a humidity of ≥90% for 24h, place it in a pressure autoclave for autoclave curing at 3.3Mpa and 196℃ for 5h. After autoclave curing, open the exhaust valve, and after the pressure in the autoclave decreases to normal pressure and the temperature decreases to normal temperature, take out the aggregate to obtain low-carbon aggregate primary product d.

[0097] Step five: Place the low-carbon aggregate primary product d in a rapid carbonization box, and carbonize it at a temperature of 20℃±5℃, a carbon dioxide concentration of 1.30%, and a relative humidity of 73% for 125h. Obtain the low-carbon aggregate finished product.

[0098] According to the test methods in GB / T 14685-2022 and GB / T 17431.2-2010, test the apparent density, water absorption, and cylinder compressive strength of the above three kinds of low-carbon aggregate, and compare them with the aggregate purchased on the market as a comparative example. The results are shown in Table 1.

[0099] According to GB 5085.3-2007, the leaching toxicity test is carried out on the three kinds of aggregates, and the leaching concentration threshold of several heavy metal elements specified in GB 5085.3-2007, and the surface water and groundwater quality standards in GB 3838-2002 and GB / T 14848-2017 are compared, and the results are shown in Table 2.

[0100] Table 1 test results

[0101]

[0102]

[0103] Table 2 leaching toxicity test results (mg / L)

[0104]

[0105] Therefore, the performance of the low-carbon aggregate prepared by the present application meets the standard requirements and is better than the performance of the existing similar products on the market. The leaching concentration of several heavy metal elements is far lower than the threshold of leaching toxicity identification, and also meets the Class I standard requirements of surface water and groundwater.

[0106] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for the production of a low carbon aggregate based on solid waste, characterized in that, The application relates to a solid waste layer (1) and a stable layer (2) and a pressure-bearing layer (3) which are sequentially wrapped in the solid waste layer (1) from inside to outside; the thicknesses of the solid waste layer (1), the stable layer (2) and the pressure-bearing layer (3) are determined according to the particle size range of low-carbon aggregates as follows: when the particle size range of the low-carbon aggregates is between 5.0 mm and 10.0 mm, the diameter of the solid waste layer (1) is 0.3 mm to 2.36 mm, the thickness of the stable layer (2) is 0.3 mm to 2.36 mm, and the thickness of the pressure-bearing layer (3) is 1.18 mm to 3.3 mm; when the particle size range of the low-carbon aggregates is between 10.0 mm and 20.0 mm, the diameter of the solid waste layer (1) is 0.6 mm to 4.5 mm, the thickness of the stable layer (2) is 0.6 mm to 4.5 mm, and the thickness of the pressure-bearing layer (3) is 2.36 mm to 8.0 mm; when the particle size range of the low-carbon aggregates is between 20.0 mm and 40.0 mm, the diameter of the solid waste layer (1) is 1.18 mm to 9.5 mm, the thickness of the stable layer (2) is 2.36 mm to 8.0 mm, and the thickness of the pressure-bearing layer (3) is 4.5 mm to 12.5 mm; the solid waste layer (1) comprises, in percentage by mass, 10% to 25% of garbage incineration fly ash, 13% to 30% of slag, 22% to 37% of red mud, 10% to 20% of calcium carbide slag and 10% to 26% of other components; the other components are composed of one or more of phosphogypsum, tailing micro powder, stone powder, dust removal ash, phosphorus slag, mercury slag, chromium slag, boron slag and lithium slag in any proportion; the stable layer (2) comprises, in percentage by mass, 20% to 35% of steel slag, 30% to 55% of mineral slag, 5% to 15% of desulfurization gypsum, 10% to 25% of fly ash and 0.5% to 1.5% of Na2CO3; the pressure-bearing layer (3) comprises, in percentage by mass, 15% to 25% of silica ash, 10% to 25% of steel slag, 30% to 50% of mineral slag, 5% to 15% of desulfurization gypsum and 5% to 15% of cement; the preparation method comprises the following steps: step one, preparation of the solid waste layer (1): excess stable layer powder is mixed and stirred uniformly according to a proportion, and then is placed in a first hopper for standby; step two, preparation of the stable layer (2): excess stable layer powder is mixed and stirred uniformly according to a proportion, and then is placed in a second hopper for standby; step three, preparation of the pressure-bearing layer (3): excess pressure-bearing layer powder is mixed and stirred uniformly according to a proportion, and then is placed in a third hopper for standby; in the formula, n is the rotating speed, and the unit is r / min; in step one, after water spraying is completed, the disc is kept rotating and observed; when more than 80% of the particles reach the diameter of the solid waste layer, the disc granulator is kept rotating for 3 min to 5 min, and then is turned off; in step four, the curing box is cured for 16 h to 24 h under the condition of a temperature of 20 DEG C plus or minus 1 DEG C and a humidity of greater than or equal to 90%; then the curing box is placed in a pressure steam kettle for steam pressure curing under the condition of 2.0 MPa to 3.5 MPa and 170 DEG C to 200 DEG C for 2 h to 5 h; after the steam pressure curing is completed, an exhaust valve is opened for exhaust. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ After the solid waste layer (1) is mixed and stirred uniformly, the powder is weighed X kg is uniformly arranged in the disc granulator, the rotating disc is opened, and the mixed powder is sprayed with water at a rate of 0.27 X 0.32 X， kg / m3 ； kg / m3 a kg / m3 m 1; Step two, in the low carbon aggregate initial product a The surface is wrapped with the stable layer (2): ​ The low-carbon aggregate primary product a The disc is placed in the turntable of the disc granulator, and the angle between the turntable and the horizontal plane is... ​ Adjust the temperature to 38°~43°; turn on the disc granulator and simultaneously open the first hopper, allowing the stabilized layer powder in the first hopper to fall into the turntable in batches, with the mass of the stabilized layer powder falling each time controlled at 0.

15. m 1~0.25 m 1. After each feeding, turn on the sprayer and spray water at a rate of 0.23 to 0.28 times the mass of the powder falling into the disc. Then the first hopper is opened again to discharge the material, and the above steps are repeated until more than 80% of the particles reach the diameter of the stable layer, and then the disc granulator is kept rotating for 5-8 min before being turned off; the particles that do not meet the target particle size are screened out to obtain the low-carbon aggregate primary product b The mass of the low-carbon aggregate primary product b is weighed as the mass m 2 . Step three, in the low carbon aggregate initial product b The surface is wrapped around the pressure layer (3): ​ The low-carbon aggregate primary product b Placed in the turntable of a disc granulator; the angle between the turntable and the horizontal plane ​ Adjust the temperature to 30°~36°; turn on the disc granulator and simultaneously open the second hopper, so that the pressure-bearing layer powder in the second hopper falls into the turntable in batches. Then the second hopper is opened again, and the above steps are repeated until more than 80% of the particles reach the diameter of the pressure layer, and the rotating disc is kept rotating for 6-10 min after the diameter of the pressure layer is reached, the disc granulator is closed, and the particles that do not meet the target particle size are screened out to obtain the low-carbon aggregate primary product c ; Step four, the low-carbon aggregate initial product c After curing in the curing box, it is placed in a pressure steam kettle for curing. After the pressure in the pressure steam kettle is reduced to normal pressure and the temperature is reduced to normal temperature, the low-carbon aggregate initial product is obtained d ; Step 5, process the low-carbon aggregate raw material. d Carbonize in a rapid carbonization box to obtain low-carbon aggregate finished product; In step one, the rotating speed of the disc granulator is controlled between 200-400 rpm. between 200-400 rpm. ​ ​ is the included angle between the rotating disc and the horizontal plane, the included angle is the inclination angle, and the value is controlled to be 40°-45°; d Diameter of the turntable, the value control in 0.5m~8.5m.

2. The method of producing a low carbon aggregate based on solid waste according to claim 1, characterized in that, ​ 3. The method of producing a low carbon aggregate based on solid waste according to claim 1, characterized in that, In step two, the included angle between the rotating disc and the horizontal plane ​ Adjust to 38°~43°, and calculate the rotating speed according to the rotating speed control formula.

4. The method of producing a low carbon aggregate based on solid waste according to claim 1, characterized in that, The quality control of the stable layer powder in step two is 0.15 m 1 0.25 m 1. After each feeding, the sprayer is opened, and the amount of water sprayed each time is 0.23-0.28 of the quality of the powder falling into the disc.

5. The method of producing a low carbon aggregate based on solid waste according to claim 1, characterized in that, In step three, the included angle between the rotating disc and the horizontal plane ​ Adjust to 30°~36°, and calculate the rotating speed according to the rotating speed control formula; the mass of the pressure-bearing layer powder falling into each time is controlled to be 0.20 m 2~0.30 m 2, after each time of discharging, open the sprayer, and the water spraying amount each time is 0.19~0.24 of the mass of the pressure-bearing layer powder falling into the rotating disc.

6. The method of producing a low carbon aggregate based on solid waste according to claim 1, characterized in that, ​ 7. The method of producing a low carbon aggregate based on solid waste according to claim 1, characterized in that, Step five, the low-carbon aggregate primary product is obtained by carbonizing the low-carbon aggregate primary product in a carbonization device at 20℃±5℃, a carbon dioxide concentration of 0.85~1.50%, and a relative humidity of 65%~75% for 72h~144h. d In a carbonization device at 20℃±5℃, a carbon dioxide concentration of 0.85~1.50%, and a relative humidity of 65%~75% for 72h~144h, a low-carbon aggregate final product is obtained.

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