Ecological building block prepared from river silt and method and device thereof

Abstract

The present disclosure relates to an ecological building block prepared from river silt and a method and device thereof, the method comprising: S1, removing garbage from the original river silt and separating sand and gravel to obtain pre-treated river silt; adding auxiliary agents to the pre-treated river silt for passivation conditioning to obtain passivated river silt; the auxiliary agents include calcium oxide, iron salt, polyacrylamide and bentonite; S2, dehydrating the passivated river silt to obtain a silt cake; crushing the silt cake into dispersed bottom mud with a particle size not exceeding 1 mm; S3, mixing the dispersed bottom mud with cement, coarse aggregate and fine aggregate, pressing and forming, and then standing to obtain an ecological building block. The device for preparing ecological building blocks from river silt disclosed in the present disclosure comprises a cutter suction dredger, a sand and gravel separator, a silt thickener, a silt dewaterer, a silt crusher and a brick press. The heavy metal ions of the ecological building blocks disclosed in the present disclosure are passivated, and the environmental protection performance and compression resistance are excellent.

Description

Technical Field

[0001] The present disclosure relates to ecological bricklaying technology, and in particular, to an ecological brick prepared from river silt and a method and device thereof. Background Art

[0002] River silt is one of the solid wastes generated during the comprehensive improvement of urban rivers. There are many urban rivers in my country. With the implementation of the national river chief system and the one-river-one-policy system, river dredging will inevitably produce a large amount of silt. The disposal of urban silt is extremely difficult today. At present, most urban river silt adopts the simple disposal method of landfill, which occupies landfill space and has the hidden danger of secondary pollution. How to effectively dispose of and recycle river silt is of great significance to solving the problem of river silt and building a resource-saving and environmentally friendly beautiful China.

[0003] A lot of research and application have been carried out on the resource utilization of sludge at home and abroad, which can be mainly divided into: land use, construction and filling materials, production of ceramsite, etc. In terms of building materials, the main uses are ecological bricks and ecological blocks, roadbed backfill earthwork, etc. At present, a large number of recycled products are needed in urban construction projects, and the country encourages their use, including construction projects, municipal projects, water projects and landscape projects that require a large number of ecological blocks. Existing invention patents and research literature have proposed the use of river sludge to produce sintered bricks, composite curing materials, and unburned bricks, such as patent numbers CN101475397A, CN103086666A, etc., but there are still some shortcomings. First, the amount of solid waste added to the raw materials of bricks is relatively low, and a large amount of waste cannot be disposed of; second, the performance of sludge bricks is poor and the scope of application is limited; third, the product lacks environmental safety evaluation, and the public acceptance is not high. The existing ecological bricks prepared from river silt are often unsafe to use due to the presence of toxic substances such as heavy metals. How to reduce the content of toxic substances in river silt ecological bricks is a technical problem that needs to be solved urgently. Summary of the invention

[0004] The purpose of the present disclosure is to provide an ecological building block prepared from river silt and a method and device thereof. The heavy metal ions in the ecological building block of the present disclosure are effectively passivated and the environmental protection performance is significantly improved.

[0005] In a first aspect, the present disclosure provides a method for preparing ecological building blocks from river silt, the method comprising the following steps: S1, removing garbage and separating sand and gravel from the original river silt to obtain pretreated river silt; adding auxiliary agents to the pretreated river silt for passivation conditioning to obtain passivated river silt; the auxiliary agents include calcium oxide, iron salt, polyacrylamide and bentonite; S2, dehydrating the passivated river silt to obtain a silt cake; crushing the silt cake into dispersed sludge with a particle size not exceeding 1 mm; S3, mixing the dispersed sludge with cement, coarse aggregate and fine aggregate, pressing and forming, and then standing to obtain ecological building blocks.

[0006] Optionally, with respect to the weight of dry river sludge per ton, the amount of calcium oxide is 50-80 kg, the amount of iron salt is 40-60 kg, the amount of polyacrylamide is 0.4-1.0 kg, and the amount of bentonite is 30-70 kg.

[0007] Optionally, the iron salt in step S1 includes ferric chloride and / or ferrous sulfate.

[0008] Optionally, the original river silt contains the following components in weight proportions: SiO2 45-60%, Al2O3 20-30%, Fe2O3 3-5%, CaO, MgO, Na2O and K2O 1-8%, and organic matter 5-15%.

[0009] Optionally, the weight proportions of the components in the ecological building block are: dispersed sludge 15-25%, cement 15-20%, coarse aggregate 40-50% and fine aggregate 20-30%.

[0010] In a second aspect, the present disclosure provides an ecological building block prepared according to the above method.

[0011] In a third aspect, the present disclosure provides a device for preparing ecological building blocks from river silt, the device comprising a cutter suction dredger, a sand and gravel separator, a sludge thickener, a sludge dewatering machine, a sludge crusher and a brick press, the cutter suction dredger is connected to the sand and gravel separator through a first sludge pump, the first sludge pump is used to transport the sludge after dredging by the cutter suction dredger to the sand and gravel separator; the sand and gravel separator is connected to the sludge thickener through a second sludge pump, the second sludge pump is used to transport the sludge after large-size sand and gravel are separated by the sand and gravel separator to the sludge thickener; the sludge thickener is also connected to a An auxiliary agent feeder is used to feed auxiliary agent into the sludge concentrator. The sludge concentrator is connected to the sludge dewatering machine through a third sludge pump. The third sludge pump is used to transport the sludge concentrated by the sludge concentrator to the sludge dewatering machine for dehydration to obtain a mud cake; the sludge dewatering machine is connected to the sludge crusher through a first conveyor belt. The first conveyor belt is used to transport the mud cake obtained by the sludge dewatering machine to the sludge crusher for crushing; the sludge crusher is connected to the brick press through a second conveyor belt. The second conveyor belt is used to transport the dispersed bottom mud obtained by the sludge crusher to the brick press for pressing and molding.

[0012] Optionally, the device further includes a crusher, which is connected to the sand and gravel separator via a third conveyor belt, and the third conveyor belt is used to transport the large-diameter sand and gravel separated from the sludge by the sand and gravel separator to the crusher for crushing.

[0013] Optionally, the device further comprises a tail water purifier, wherein the tail water purifier is connected to the sludge dewatering machine via a fourth sludge pump, and the fourth sludge pump is used to purify the tail water obtained by dehydration of the sludge dewatering machine.

[0014] Optionally, the device further comprises an auxiliary agent storage tank, and a material connection is provided between the auxiliary agent feeder and the auxiliary agent storage tank.

[0015] The present invention can effectively utilize river silt, and the method for preparing ecological building blocks can effectively passivate heavy metal ions. The prepared ecological building blocks are more environmentally friendly, the preparation process does not require firing, and the ecological building blocks have excellent compressive strength.

[0016] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0018] Figure 1It is a structural schematic diagram of a specific embodiment of the device for preparing ecological building blocks from river silt disclosed in the present invention.

[0019] Description of Reference Numerals

[0020] 1 Cutter Suction Dredger 2 Sand and Gravel Separator 3 Silt Thickener

[0021] 4 sludge dewatering machine 5 sludge crusher 6 brick press

[0022] 7 Crusher 8 Auxiliary agent storage tank 9 Tail water purifier

[0023] 10 auxiliary agent feeder 11 first sludge pump 12 second sludge pump

[0024] 13 The third sludge pump 14 The first conveyor belt 15 The second conveyor belt

[0025] 16 Fourth sludge pump 17 Third conveyor belt DETAILED DESCRIPTION

[0026] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0027] In a first aspect, the present disclosure provides a method for preparing ecological building blocks from river sludge, the method comprising the following steps: S1, garbage can be removed from the original river sludge and sand and gravel can be separated to obtain pre-treated river sludge; auxiliary agents can be added to the pre-treated river sludge for passivation conditioning to obtain passivated river sludge; the auxiliary agents may include calcium oxide, iron salt, polyacrylamide and bentonite; S2, the passivated river sludge can be dehydrated to obtain a sludge cake, the moisture content of which can be 25-50% by weight; The silt cake is crushed into dispersed sludge with a particle size not exceeding 1 mm; S3, the dispersed sludge can be mixed with cement, coarse aggregate and fine aggregate, pressed into shape and then allowed to stand to obtain ecological building blocks, the cement can be 32.5 grade ordinary Portland cement, the coarse aggregate can be obtained by crushing construction waste, the particle size of the coarse aggregate can be greater than 4.75 mm and less than 10 mm, the fine aggregate can be obtained by crushing construction waste, and can come from sand separated from river sludge, and the particle size of the fine aggregate can be no greater than 4.75 mm.

[0028] In step S1, the material with a particle size of less than 2 mm in the original river sludge can be sequentially subjected to subsequent steps to prepare sludge cakes, the material with a particle size of 2-3 mm is mainly separated sand, which can be used as subsequent fine aggregate, and the material with a particle size of more than 3 mm can be removed as garbage; the passivated river sludge obtained in step S1 can be a slurry with a moisture content of more than 90% by weight. The water dehydrated from the river sludge in step S2 can be purified to obtain clean water, which can be used as water for ecological block maintenance, can also be transported through pipelines as dredging and excavation water for recycling, and can also be used as water for ecological block maintenance. The standing still in step S3 can allow the ecological building blocks to be cured. The standing still can be a natural curing process, and the natural curing time can be 7-28 days. During the natural curing process of standing still, the formed ecological building blocks can preferably be sprayed with water vapor and then continue to stand still. After many experiments, it was found that with the extension of the natural curing process time, the compressive strength of the ecological building blocks will gradually increase. After the compressive strength reaches the peak value, it will no longer increase with the extension of the curing time.

[0029] There are often many harmful heavy metal ions in the original river silt. During the use of the existing ecological bricks prepared from the river silt, many heavy metal ions will be leached. Therefore, the method disclosed in the present invention passivates the heavy metal ions in the original river silt twice: the first passivation, in step S1, the river silt is passivated by adding an auxiliary agent to the pretreated river silt, and the polyacrylamide and bentonite in the auxiliary agent can effectively passivate the heavy metal ions in the river silt, so that the concentration of heavy metal ions that can be leached in the prepared ecological blocks during subsequent use is significantly reduced; the second passivation, in step S3, the heavy metal ions in the dispersed sediment are further passivated and stabilized by cement, and the heavy metal ions in the ecological blocks are further sealed after static maintenance. The various performance indicators of the ecological building blocks prepared by the method disclosed in the present invention can meet the standards of GB28635-2012 and GB / T8239-2014, and when the leachate of the ecological building blocks disclosed in the present invention is tested in accordance with the "Toxicity Identification of Leachate of Hazardous Waste Identification Standard" (GB5085.3-2007), the heavy metal ion concentration of the ecological building block leachate can meet the Class IV water limit requirements of the "Surface Water Environmental Quality Standard" (GB3838-2002), that is, the environmental safety of the ecological building blocks prepared by the method disclosed in the present invention is significantly higher than that of existing silt bricks.

[0030] According to the present disclosure, relative to the weight of dry river sludge per ton, the amount of calcium oxide can be 50-80kg, the amount of iron salt can be 40-60kg, the amount of polyacrylamide can be 0.4-1.0kg, and the amount of bentonite can be 30-70kg. In the method of the present disclosure, the iron salt can be a dehydrating agent, the calcium oxide can be a conditioning agent, and the polyacrylamide (PAM) and bentonite can be passivating agents.

[0031] According to the present disclosure, the iron salt in step S1 may include ferric chloride and / or ferrous sulfate.

[0032] According to the present disclosure, the original river silt may contain the following components in weight proportions: SiO2 45-60%, Al2O3 20-30%, Fe2O3 3-5%, CaO, MgO, Na2O and K2O 1-8%, and organic matter 5-15%.

[0033] According to the present disclosure, the weight proportion of the components in the ecological building block can be: 15-25% dispersed sludge, 15-20% cement, 40-50% coarse aggregate and 20-30% fine aggregate. Preferably, the weight proportion of the components in the ecological building block can be: 17.0% dispersed sludge, 15.9% cement, 40.9% coarse aggregate and 26.2% fine aggregate. The ecological building block obtained under this preferred ratio has better performance parameters.

[0034] The method disclosed in the present invention can make full use of river silt and construction waste, replace natural sand and gravel, save precious natural resources, avoid the environmental pollution caused by the exploitation of natural sand and gravel, solve the problem of the outlet of urban silt disposal, and also make use of construction waste, turn construction waste into resources, create economic value and obtain good environmental benefits, which is of great significance to the construction of a beautiful China. Compared with the existing sludge sintered brick technology, the process of preparing ecological blocks disclosed in the present invention is free of burning, but the obtained ecological blocks have high strength, and all indicators can meet the requirements of national standards, and the environmental safety of the obtained ecological block leachate is significantly improved through the ingenious passivation process. Therefore, under the premise of not generating secondary pollution, the ecological blocks disclosed in the present invention can have a wider range of applications.

[0035] In a second aspect, the present disclosure provides an ecological building block prepared according to the above method. The ecological building block disclosed in the present disclosure has high strength and environmental leaching safety, and can be used as a brick material or permeable brick in the construction of sponge cities, municipal engineering, landscape engineering and water engineering, and can also be used as greenway bricks, sidewalk bricks, square bricks, parking lot bricks, embankment slope protection, roadbed protection and soil and water conservation bricks, etc.

[0036] In the third aspect, the present disclosure provides a device for preparing ecological building blocks from river silt, which may include a cutter suction dredger 1, a sand and gravel separator 2, a sludge thickener 3, a sludge dewatering machine 4, a sludge crusher 5 and a brick press 6. The cutter suction dredger 1 and the sand and gravel separator 2 may be connected via a first sludge pump 11, which may be used to transport the sludge desilted by the cutter suction dredger 1 to the sand and gravel separator 2; the sand and gravel separator 2 and the sludge thickener 3 may be connected via a second sludge pump 12, which may be used to transport the sludge after large-size sand and gravel are separated by the sand and gravel separator 2 to the sludge thickener 3; the sludge thickener 3 may also be connected with a device for conveying the sludge to the The auxiliary agent feeder 10 for feeding auxiliary agents into the sludge concentrator 3, the sludge concentrator 3 and the sludge dewatering machine 4 can be connected through a third sludge pump 13, and the third sludge pump 13 can be used to transport the sludge concentrated by the sludge concentrator 3 to the sludge dewatering machine 4 for dehydration to obtain a mud cake; the sludge dewatering machine 4 and the sludge crusher 5 can be connected through a first conveyor belt 14, and the first conveyor belt 14 can be used to transport the mud cake obtained by the sludge dewatering machine 4 to the sludge crusher 5 for crushing; the sludge crusher 5 and the brick press 6 can be connected through a second conveyor belt 15, and the second conveyor belt 15 can be used to transport the dispersed bottom mud obtained by the sludge crusher 5 to the brick press 6 for pressing and forming. The brick press 6 can produce ecological blocks of different specifications and types by replacing different machine mouth models.

[0037] The river sludge can be desilted and extracted by the cutter suction dredger. The river sludge extracted by the cutter suction dredger can be pumped to the sand and gravel separator through the first sludge pump. The sand and gravel separator can separate the substances with a particle size of more than 2mm in the river sludge. The particles with a particle size of 2-3mm are mainly separated sand, which can be used as subsequent fine aggregates. The particles with a particle size of more than 3mm can be removed as garbage to obtain pre-treated river sludge; the pre-treated river sludge can be pumped to the sludge separator through the second sludge pump. The concentrator can also add auxiliary agents to the sludge in the sludge concentrator through an auxiliary agent feeder to passivate and condition the sludge, so as to obtain passivated and concentrated river sludge; the passivated and concentrated river sludge can be pumped to the sludge dewatering machine through the third sludge pump for dehydration to obtain a mud cake; the mud cake can be crushed by a sludge crusher to obtain dispersed sludge with a particle size of less than 1 mm, and the dispersed sludge can be evenly mixed with cement, coarse aggregate and fine aggregate and then transported to a brick press for pressing and forming, and ecological building blocks can be obtained after static maintenance.

[0038] According to the present disclosure, the device may further include a crusher 7, and the crusher 7 and the sand and gravel separator 2 may be connected via a third conveyor belt 17, and the third conveyor belt 17 may be used to transport the large-grained sand and gravel separated from the sludge by the sand and gravel separator 2 to the crusher 7 for crushing. The crushed small-grained sand and gravel may be used as coarse aggregate or fine aggregate, and the large-grained sand and gravel in the sludge may be used as waste.

[0039] According to the present disclosure, the device may further include a tail water purifier 9, and the tail water purifier 9 and the sludge dewatering machine 4 may be connected via a fourth sludge pump 16, and the fourth sludge pump 16 may be used to purify the tail water obtained by dehydrating the sludge dewatering machine 4. The tail water may be reused after purification, for example, it may be used in the static curing process of the eco-blocks, and may be sprayed on the eco-blocks in the form of water vapor (water mist) to improve the compressive strength of the blocks.

[0040] According to the present disclosure, the device may further include an auxiliary agent storage tank 8, and a material connection may be provided between the auxiliary agent feeder 10 and the auxiliary agent storage tank 8. The auxiliary agent stored in the auxiliary agent storage tank may first be transported to the auxiliary agent feeder, and the auxiliary agent feeder may then feed the auxiliary agent into the sludge of the sludge concentrator to passivate the heavy metal ions in the sludge, so that the ecological blocks prepared by the device for preparing ecological blocks from river sludge of the present disclosure may be used more environmentally friendly. Specifically, the various performance indicators of the ecological blocks produced by the device of the present disclosure may meet the standards of GB28635-2012 and GB / T8239-2014, and when the ecological block leachate of the present disclosure is tested in accordance with the "Hazardous Waste Identification Standard Leachate Toxicity Identification" (GB5085.3-2007), the heavy metal ion concentration of the ecological block leachate may meet the Class IV water limit requirements of the "Surface Water Environmental Quality Standard" (GB3838-2002).

[0041] According to the present disclosure, the sand and gravel separator 2, the sludge thickener 3, the sludge dewatering machine 4 and the sludge crusher 5 can be located on a movable platform. The position of the movable platform can be changed in real time as needed, so that the sand and gravel separator 2, the sludge thickener 3, the sludge dewatering machine 4 and the sludge crusher 5 can be operated more conveniently, which can improve work efficiency.

[0042] According to the present disclosure, the device may further include a static curing area for placing the eco-blocks pressed and formed in the brick press 6. The eco-blocks pressed and formed in the brick press need to be placed in the static curing area for natural curing, and the compressive resistance of the eco-blocks after natural curing can be improved.

[0043] According to the present disclosure, a nozzle for spraying water and / or water vapor may be provided in the static curing area. During the curing process, water and / or water vapor may be sprayed on the curing eco-blocks in an appropriate amount, and sprayed again after the eco-blocks are dried, and the process is repeated in sequence. After such a curing process, the compressive strength of the eco-blocks may be further improved.

[0044] According to the present disclosure, the outlet of the tail water purifier 9 can be fluidically connected to the nozzle, so that the purified tail water can be used again in the maintenance process of the ecological blocks.

[0045] The present invention is further described in detail by way of examples below. The following examples are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0046] Example 1

[0047] The river silt of a river in Shenzhen City, Guangdong Province is dredged by a cutter suction dredger to obtain the dredged river silt, and the dredged river silt is pumped to a sand and gravel separator through a first sludge pump. The sand and gravel separator separates substances with a particle size of more than 2 mm in the dredged river silt, wherein the particles with a particle size of more than 3 mm are regarded as garbage and removed, and the particles with a particle size of 2-3 mm are sand, which can be used as fine aggregate. After removing the garbage and separating the sand and gravel, the pretreated river silt is obtained; the pretreated river silt is pumped to a sludge concentrator through a second sludge pump, and an auxiliary agent is added to the pretreated river silt in the sludge concentrator through an auxiliary agent feeder for passivation conditioning and concentration to obtain the passivated river silt. , relative to the weight of each ton of dry river sludge, 50kg of calcium oxide, 50kg of ferric chloride, 0.5kg of polyacrylamide and 35kg of bentonite are added; the passivated river sludge is pumped to the sludge dewatering machine by the third sludge pump for dehydration to obtain a mud cake with a moisture content of 40% by weight; the mud cake is crushed into dispersed sludge with a particle size less than 1mm, 170Kg of dispersed sludge is mixed with 159Kg of cement, 409Kg of coarse aggregate and 262Kg of fine aggregate, and then pressed into 200×50×50mm by a brick press, and allowed to stand at room temperature for 7 days for curing. During the curing process, water vapor is sprayed and continued to stand to obtain permeable ecological blocks, which are ordinary solid blocks with a block strength of 46.3MPa.

[0048] Example 2

[0049] The river silt of a river in Shenzhen City, Guangdong Province is dredged by a cutter suction dredger to obtain dredged river silt, and the dredged river silt is pumped to a sand and gravel separator through a first sludge pump. The sand and gravel separator separates substances with a particle size of more than 2 mm in the dredged river silt, wherein the particles with a particle size of more than 3 mm are regarded as garbage and removed, and the particles with a particle size of 2-3 mm are sand, which can be used as fine aggregate. After removing the garbage and separating the sand and gravel, the pretreated river silt is obtained; the pretreated river silt is pumped to a sludge concentrator through a second sludge pump, and an auxiliary agent is added to the pretreated river silt in the sludge concentrator through an auxiliary agent feeder for passivation conditioning and concentration to obtain the passivated river silt, which is relatively For every ton of dry river sludge, 55kg of calcium oxide, 60kg of ferrous sulfate, 0.6kg of polyacrylamide and 40kg of bentonite are added; the passivated river sludge is pumped to a sludge dewatering machine by a third sludge pump for dehydration to obtain a mud cake with a moisture content of 45% by weight; the mud cake is crushed into dispersed sludge with a particle size of less than 1mm, 154kg of dispersed sludge is mixed with 159kg of cement, 409kg of coarse aggregate and 278kg of fine aggregate, and then pressed into 300×300×60mm by a brick press, and allowed to stand at room temperature for 28 days for curing. During the curing process, water vapor is sprayed several times and then allowed to stand to obtain a permeable ecological block, which is an ordinary solid block with a block strength of 57.6MPa.

[0050] Example 3

[0051] The river silt of a river in Shenzhen City, Guangdong Province is dredged by a cutter suction dredger to obtain dredged river silt, and the dredged river silt is pumped to a sand and gravel separator through a first sludge pump. The sand and gravel separator separates substances with a particle size of more than 2 mm in the dredged river silt, wherein the particles with a particle size of more than 3 mm are regarded as garbage and removed, and the particles with a particle size of 2-3 mm are sand, which can be used as fine aggregate. After removing the garbage and separating the sand and gravel, the pretreated river silt is obtained; the pretreated river silt is pumped to a sludge concentrator through a second sludge pump, and an auxiliary agent is added to the pretreated river silt in the sludge concentrator through an auxiliary agent feeder for passivation conditioning and concentration to obtain the passivated river silt. The weight of dry river sludge is 60kg of calcium oxide, 50kg of ferric chloride, 1.0kg of polyacrylamide and 40kg of bentonite; the passivated river sludge is pumped to the sludge dewatering machine by the third sludge pump for dehydration to obtain a mud cake with a moisture content of 40% by weight; the mud cake is crushed into dispersed sludge with a particle size less than 1mm, 170Kg of dispersed sludge is mixed with 159Kg of cement, 409Kg of coarse aggregate and 262Kg of fine aggregate, and then pressed into 600×400×150mm by a brick press, and allowed to stand at room temperature for 7 days for curing. During the curing process, water vapor is sprayed several times and then allowed to stand to obtain WE infiltration blocks. WE infiltration blocks are porous special-shaped slope protection materials with a block strength of 15.0MPa.

[0052] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0053] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0054] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A method for preparing ecological building blocks from river silt, characterized in that: The method comprises the following steps: S1, removing garbage and separating sand and gravel from the original river sludge to obtain pre-treated river sludge; adding an auxiliary agent to the pre-treated river sludge for passivation conditioning to obtain passivated river sludge; the auxiliary agent includes calcium oxide, iron salt, polyacrylamide and bentonite; S2, dehydrating the passivated river sludge to obtain a sludge cake; crushing the sludge cake into dispersed sediment with a particle size not exceeding 1 mm; S3, mixing the dispersed sludge with cement, coarse aggregate and fine aggregate, pressing and molding, and then standing to obtain an ecological building block; Relative to the weight of each ton of dry river sludge, the dosage of calcium oxide is 50-80kg, the dosage of iron salt is 40-60kg, the dosage of polyacrylamide is 0.4-1.0kg and the dosage of bentonite is 30-70kg; The original river silt contains the following components by weight: SiO2 45-60%, Al2O3 20-30%, Fe2O3 3-5%, CaO, MgO, Na2O and K2O 1-8%, and organic matter 5-15%; The weight proportions of the components in the ecological building block are: 15-25% dispersed sediment, 15-20% cement, 40-50% coarse aggregate and 20-30% fine aggregate.

2. The method according to claim 1, wherein: The iron salt in step S1 includes ferric chloride and / or ferrous sulfate.

3. An ecological building block prepared according to any one of claims 1-2.

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