Low-carbon sludge curing agent, preparation method and processing equipment thereof

Abstract

The invention discloses a low-carbon sludge curing agent, a preparation method and processing equipment thereof, and relates to the technical field of curing agents, the low-carbon sludge curing agent comprises 22-24% by weight of loess, 28-29% by weight of fly ash, 28-29% by weight of desulfurized gypsum and 19-22% by weight of cement, the raw materials comprise 23.81% by weight of loess, 28.57% by weight of fly ash, 28.57% by weight of desulfurized gypsum and 19.05% by weight of cement, the particle size of the loess is less than or equal to 0.2 mm, the particle size of the fly ash is less than or equal to 0.2 mm, and the particle size of the desulfurized gypsum is less than or equal to 0.2 mm. The fly ash needs to reach the standard of grade I and above GB / T1596-2017 Fly Ash For Cement and Concrete, the specific surface area of the granulated fly ash and the specific surface area of the desulfurized gypsum slag are both larger than or equal to 400 m < 2 > / kg, and the model of the cement is P.O42.5. The raw materials are mainly solid wastes and loess, the cement mixing amount is very small, the concepts of circular economy and green development are practiced, and the energy consumption is reduced; the operation of preparing the curing agent is simple, the cost of raw materials is low, the curing effect is good, the strength of sludge cured by the curing agent is far higher than that of uncured sludge, materials can be conveniently added into a tank body, meanwhile, the interior of the tank body is conveniently cleaned, and the stirring effect is improved.

Description

Technical Field

[0001] The invention relates to the technical field of solidifying agents, and in particular to a low-carbon sludge solidifying agent, a preparation method and processing equipment thereof. Background Art

[0002] At present, solidification technology is an effective method for sludge treatment. Through a series of chemical reactions between the solidifying agent and the sludge, the water content of the sludge can be effectively reduced and its strength can be improved. Traditional raw materials for solidifying agents include cement, lime, etc. In recent years, wastes such as fly ash, steel slag, carbide slag and garbage incineration ash have also been widely studied and used for sludge solidification and stabilization. These solidifying agents have certain effects on reducing the water content of sludge and improving its strength.

[0003] In the prior art, the preparation of curing agents is complicated, the cost of raw materials is high, and the curing effect is poor. To this end, we propose a low-carbon sludge curing agent, a preparation method and a processing equipment thereof to solve the above problems. Summary of the invention

[0004] The object of the present invention is to provide a low-carbon sludge solidifying agent, a preparation method and a processing equipment thereof, so as to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above purpose, the present invention provides the following technical solution: a low-carbon sludge solidifying agent, which comprises the following components by weight percentage: 22-24% loess, 28-29% fly ash, 28-29% desulfurized gypsum, and 19-22% cement.

[0006] Furthermore, the raw materials include, by weight percentage: 23.81% loess, 28.57% fly ash, 28.57% desulfurized gypsum, and 19.05% cement.

[0007] Furthermore, the loess particle size is less than or equal to 0.2 mm.

[0008] Furthermore, the fly ash must meet the standard of GB / T1596-2017 "Fly ash used in cement and concrete" Grade I or above.

[0009] Furthermore, the specific surface areas of the granulated fly ash and desulfurized gypsum slag are both greater than or equal to 400 m2 / kg, and the cement model is P.O42.5.

[0010] Furthermore, a method for preparing a low-carbon sludge solidifying agent specifically comprises the following steps:

[0011] S1. Calculate the mass of sludge according to the sludge volume and density in the solidification area, and calculate the amount of each raw material of the solidifying agent according to the designed ratio;

[0012] S2, drying the loess, crushing and sieving; ball-milling the fly ash and desulfurization gypsum of the power plant to the target particle size;

[0013] S3. According to the above curing agent ratio, loess, fly ash, desulfurized gypsum and cement of corresponding mass are weighed and put into a mixing device according to the designed ratio and stirred thoroughly to obtain a curing agent for curing sludge.

[0014] Furthermore, in step S1, based on the mass of wet sludge, the initial moisture content of the wet sludge is 60%-70%, and the mass percentage of the curing agent is 30%-50%.

[0015] Furthermore, a preparation device for a low-carbon sludge solidifying agent includes a tank body, a telescopic rod, a motor, a stirring rod and stirring blades. The tank body is provided with a cover plate for moving and sealing the top opening of the tank body, and a non-slip pad for increasing the friction between the cover plate and the tank body is provided at the position where the cover plate moves and contacts the tank body. The cover plate is provided with a telescopic rod, and a bracket is provided on the telescopic rod. A stirring rod is rotatably connected to the bracket, and the bottom of the stirring rod moves through the cover plate and is connected to a stirring blade for stirring the material.

[0016] Furthermore, the tank body is a stirring tank body, the diameter of the through hole on the cover plate penetrated by the stirring rod is larger than the diameter of the stirring rod, and the anti-slip pad is provided with two groups symmetrically arranged at the bottom of the cover plate and the top of the tank body.

[0017] Furthermore, the bracket is provided with a motor for driving the stirring rod to rotate, the motor driving end is connected to the stirring rod, the minimum distance between the bracket and the bottom of the tank body is greater than the length of the stirring rod, and the maximum length of the telescopic rod is less than the maximum distance between the stirring blade and the cover plate.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The raw materials are mainly solid waste and loess, with very little cement added, which practices the concept of circular economy and green development and reduces energy consumption; the preparation of the curing agent is simple and the cost of raw materials is low.

[0020] 2. The solidification effect is good. The strength of the sludge solidified by this solidifying agent is much greater than that of the unsolidified sludge.

[0021] 3. Move the cover plate upward by the crane, and the cover plate moves upward. Through the telescopic rod and the bracket, the stirring rod and the stirring blades can be moved upward with it, and the above components can be moved to the outside of the tank body, and then the material is poured into the tank body, and then the cover plate is moved downward, and the lower half of the stirring rod and the stirring blades follow and move downward and insert into the tank body, and the motor is started. The motor drives the stirring rod to rotate, and the stirring rod causes the stirring blades to rotate to stir and mix the materials. At the same time, the telescopic rod can be driven, and the telescopic rod pushes the bracket to rise and fall, so that the stirring rod and the stirring blades follow the rise and fall, and the stirring blades rise and fall to stir the materials in the tank body, making it easy to add materials into the tank body and to clean the inside of the tank body, thereby improving the stirring effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the compressive failure morphology of a 60% water content sludge solidification sample in an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the compressive failure morphology of a sludge solidification sample with a moisture content of 65% in an embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of the compressive failure morphology of a sludge solidification sample with a moisture content of 75% in an embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of the specific workflow of the curing construction method of the present invention;

[0026] Figure 5 It is a schematic diagram of the preparation equipment of the low carbon sludge solidifying agent of the present invention;

[0027] Figure 6 It is a schematic diagram of the structure of the support in the preparation equipment of the low-carbon sludge solidifying agent of the present invention.

[0028] In the figure: 1. tank body; 2. cover plate; 3. anti-slip pad; 4. telescopic rod; 5. bracket; 6. motor; 7. stirring rod; 8. stirring blade. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] A low-carbon sludge solidifying agent comprises the following components by weight percentage: 22-24% of loess, 28-29% of fly ash, 28-29% of desulfurized gypsum, and 19-22% of cement. The loess particle size is less than or equal to 0.2 mm, the fly ash must meet the GB / T1596-2017 "Fly ash used in cement and concrete" Grade I and above standards, the specific surface areas of granulated fly ash and desulfurized gypsum slag are both greater than or equal to 400 m2 / kg, and the cement model is P.O42.5; based on the mass of wet sludge, the initial moisture content of the wet sludge is 60%-70%, and the mass percentage of the solidifying agent is 30%-50%.

[0031] Example 1

[0032] The raw materials include, by weight percentage: 23.81% loess, 28.57% fly ash, 28.57% desulfurized gypsum, 19.05% cement, and the mass percentage of the above-mentioned curing agent is 40% based on the mass of wet sludge;

[0033] The moisture content of the sludge used in this embodiment is 60%. After the curing agent and sludge are fully mixed, they are loaded into a 70.7mm cubic test mold, demoulded after 24-36 hours, and subjected to a compression test after curing to the designed age. The test reference standard is: Cube compressive strength: refer to JGJ 70-2009 Basic Performance Test Method for Building Mortar; the 7d compressive strength of the solidified sludge in this embodiment is 220kPa, the 14d compressive strength is 567kPa, and the 28d compressive strength is 1563kPa. The failure morphology of the solidified samples at different periods is as follows: Figure 1 shown.

[0034] Example 2

[0035] The raw materials include, by weight percentage: 23.81% loess, 28.57% fly ash, 28.57% desulfurized gypsum, 19.05% cement, and the mass percentage of the above-mentioned curing agent is 40% based on the mass of wet sludge;

[0036] The moisture content of the sludge used in this embodiment is 65%. After the curing agent and sludge are fully mixed, they are loaded into a 70.7mm cubic test mold, demoulded after 24-36 hours, and subjected to a compression test after curing to the designed age. The test reference standard is: Cube compressive strength: refer to JGJ 70-2009 Basic Performance Test Method for Building Mortar; the 7d compressive strength of the solidified sludge in this embodiment is 305kPa, the 14d compressive strength is 643kPa, and the 28d compressive strength is 1401kPa. The failure morphology of the solidified samples at different periods is as follows: Figure 2 shown.

[0037] Example 3

[0038] The raw materials include, by weight percentage: 23.81% loess, 28.57% fly ash, 28.57% desulfurized gypsum, 19.05% cement, and the mass percentage of the above-mentioned curing agent is 40% based on the mass of wet sludge;

[0039] The moisture content of the sludge used in this embodiment is 75%. After the curing agent and sludge are fully mixed, they are loaded into a 70.7 mm cubic test mold, demoulded after 24-36 hours, and subjected to a compression test after curing to the designed age. The test reference standard is: Cube compressive strength: refer to JGJ 70-2009 Basic Performance Test Method for Building Mortar; the 7d compressive strength of the solidified sludge in this embodiment is 70 kPa, the 14d compressive strength is 506 kPa, and the 28d compressive strength is 697 kPa. The failure morphology of the solidified samples at different periods is as follows: Figure 3 shown.

[0040] It can be seen from the above embodiments that when the initial moisture content is low, the integrity of the sample is poor and the sample exhibits brittle failure. As the initial moisture content increases, the integrity of the sample improves, and the sample still has quite good integrity when it is destroyed. When the moisture content continues to increase, the solidified sludge sample has a large amount of water, is not easy to shape, and has low strength. Although the sample still has good integrity when it is destroyed, its compressive resistance is greatly reduced. Comprehensively considering that the initial moisture content of the sludge is 60%-65%, the x solidification effect is best.

[0041] A method for preparing a low-carbon sludge solidifying agent specifically comprises the following steps:

[0042] S1. Calculate the mass of sludge according to the sludge volume and density in the solidification area, and calculate the amount of each raw material of the solidifying agent according to the designed ratio;

[0043] S2. Dry the loess, crush and sieve it; ball-mill the fly ash and desulfurization gypsum from the power plant to the target particle size (or directly use the finished product that meets the above requirements);

[0044] S3. According to the above curing agent ratio, loess, fly ash, desulfurized gypsum and cement of corresponding mass are weighed and put into a mixing device according to the designed ratio and stirred thoroughly to obtain a curing agent for curing sludge.

[0045] 1. The raw materials are mainly solid waste and loess, with very little cement content, which practices the concept of circular economy and green development and reduces energy consumption; the preparation of curing agent is simple and the cost of raw materials is low;

[0046] 2. The solidification effect is good. The strength of the sludge solidified by this solidifying agent is much greater than that of the unsolidified sludge.

[0047] See also Figure 5-6A preparation device for a low-carbon sludge solidifying agent comprises a tank body 1, a telescopic rod 4, a motor 6, a stirring rod 7 and a stirring blade 8. The tank body 1 is provided with a cover plate 2 for moving and sealing the top opening of the tank body 1. The cover plate 2 is provided with an anti-skid pad 3 for increasing the friction between the cover plate 2 and the tank body 1 at the place where the cover plate 2 moves and contacts the tank body 1. The cover plate 2 is provided with a telescopic rod 4, and the telescopic rod 4 is provided with a bracket 5. The bracket 5 is rotatably connected with a stirring rod 7. The bottom of the stirring rod 7 moves through the cover plate 2 and is connected with a stirring blade 8 for stirring materials. The tank body 1 is a stirring tank body. The diameter of the through hole on the cover plate 2 penetrated by the stirring rod 7 is larger than the diameter of the stirring rod 7. The anti-slip pad 3 is provided with two groups symmetrically arranged at the bottom of the cover plate 2 and the top of the tank body 1. The bracket 5 is provided with a motor 6 for driving the stirring rod 7 to rotate. The driving end of the motor 6 is connected to the stirring rod 7. The minimum distance between the bracket 5 and the bottom of the tank body 1 is greater than the length of the stirring rod 7. The maximum length of the telescopic rod 4 is less than the maximum distance between the stirring blade 8 and the cover plate 2. A counterweight block can be added to the cover plate 2. The cover plate 2 is provided with a lifting ear. The telescopic rod 4 can be an electric, hydraulic or pneumatic telescopic rod, etc.

[0048] By moving the cover plate 2 upward by the crane, the cover plate 2 moves upward, and the stirring rod 7 and the stirring blade 8 are moved upward with it through the telescopic rod 4 and the bracket 5, and the above-mentioned components can be moved to the outside of the tank body 1 (to facilitate adding materials into the tank body 1 through the equipment, and to facilitate cleaning the inside of the tank body 1 by equipment or manually), and then the material is poured into the tank body 1, and then the cover plate 2 is moved downward, and the lower half of the stirring rod 7 and the stirring blade 8 are moved downward with it and inserted into the tank body 1, and the motor 6 is started, and the motor 6 drives the stirring rod 7 to rotate, and the stirring rod 7 causes the stirring blade 8 to rotate to stir and mix the materials, and at the same time, the telescopic rod 4 can be driven, and the telescopic rod 4 pushes the bracket 5 to rise and fall, so that the stirring rod 7 and the stirring blade 8 are lifted and lowered, and the stirring blade 8 is lifted and lowered to stir the materials in the tank body 1, making it convenient to add materials into the tank body 1 and to clean the inside of the tank body 1, thereby improving the stirring effect.

[0049] The specific working process of the curing construction method is as follows:

[0050] Step 1: Site leveling: Use a bulldozer to level the site within 10m around the sludge pit to facilitate the storage of subsequent test materials and the layout of curing equipment;

[0051] Step 2: Depth exploration: Use ropes to divide the solidification area, use a spiral drill to drill holes every 2m in each area to determine the solidification depth, and monitor in real time during construction to prevent damage to the anti-seepage membrane at the bottom of the sludge;

[0052] Step 3, sampling and testing; for each solidification area, use the stirring equipment to stir up and down, left and right, front and back, and mix the deep and shallow sludge evenly. Note that the stirring rod should be marked with depth before construction, and always pay attention to the depth of the stirring rod entering the sludge during stirring; sample the sludge in each solidification area, test its moisture content and density. If the moisture content is not within the design range, adjust the moisture content to a reasonable range by adding admixtures, and re-sample for density test;

[0053] Step 4, material transportation and processing, curing agent preparation; calculate the mass of the sludge according to the sludge volume and density of the curing area, calculate the amount of each raw material of the curing agent according to the designed ratio, and then use a dump truck to transport the raw materials to the site, and do a good job of waterproofing the materials. Use a sand screener to pass the required mass of loess through a 0.2mm sieve for subsequent curing agent configuration, and use a crane to move the cover plate 2 upward. The cover plate 2 moves upward, and the stirring rod 7 and the stirring blade 8 move upward with the telescopic rod 4 and the bracket 5. The above components can be moved to the outside of the tank body 1 (to facilitate the addition of materials into the tank body 1 through the equipment, and to facilitate the equipment or manual cleaning of the inside of the tank body 1) , put the sieved loess, fly ash, desulfurized gypsum and cement into the tank body 1 according to the designed proportion, then move the cover plate 2 downward, the lower half of the stirring rod 7 and the stirring blade 8 move downward accordingly and insert into the tank body 1, start the motor 6, the motor 6 drives the stirring rod 7 to rotate, the stirring rod 7 rotates the stirring blade 8 to stir and mix the materials, and at the same time, the telescopic rod 4 can be driven, the telescopic rod 4 pushes the bracket 5 to rise and fall, so that the stirring rod 7 and the stirring blade 8 follow the rise and fall, the stirring blade 8 rises and falls to stir the materials in the tank body 1, and fully stir to obtain the curing agent for curing the sludge, so that it is convenient to add materials into the tank body 1, and it is convenient to clean the inside of the tank body 1, thereby improving the stirring effect;

[0054] Step 5: Connect and debug the curing equipment. The in-situ curing system equipment is transported in blocks and assembled in a centralized manner. After the feeding system, conveying system and stirring device are assembled, the machine is checked for abnormalities through trial operation and resolved in a timely manner.

[0055] Step 6, solidification construction; sink the powerful stirring head into the sludge at a set rate, first stir it thoroughly to make the sludge evenly distributed, and spray powder in time according to the designed amount of curing agent added. The powder spraying rate is adjusted according to the characteristics of the sludge, and the lifting rate is lowered. At the same time, in order to make up for the deficiency of the first stirring and improve the utilization rate of the agent, the sludge and the agent are fully mixed. Stir again and feed synchronously, increase the sinking and rising rates, and repeat the cycle until all the required curing agent raw materials are pumped into the sludge. After the construction is completed, continue to solidify the sludge in other areas as described above until all areas are solidified;

[0056] Step 7, site maintenance: After the solidification is completed, HDPE film is used as a temporary covering film to prevent rain and maintain the solidified sludge;

[0057] Step 8, effect evaluation: when the curing age reaches 7d, 14d and 28d, drilling samples are taken at equal intervals along the radial and tangential directions to measure the moisture content and permeability coefficient of the solidified sludge, and the bearing capacity of the solidified sludge is measured by a load plate load test to evaluate the curing effect;

[0058] Step 9, laying the cushion layer; after the sludge is solidified, in order to prevent the external environment from eroding the solidified sludge and to further improve the bearing capacity of the solidified area, an HDPE anti-seepage membrane can be laid on the solidified site and a soil cushion layer of a certain thickness can be laid on the anti-seepage membrane and compacted with a roller. After the construction is completed, the site should be drained.

[0059] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A low-carbon sludge solidifying agent, characterized in that: The low-carbon sludge solidifying agent comprises the following components by weight percentage: 22-24% loess, 28-29% fly ash, 28-29% desulfurized gypsum, and 19-22% cement.

2. A low-carbon sludge solidifying agent according to claim 1, characterized in that: The raw materials include, by weight percentage: 23.81% loess, 28.57% fly ash, 28.57% desulfurized gypsum, and 19.05% cement.

3. A low-carbon sludge solidifying agent according to claims 1-2, characterized in that: The loess particle size is less than or equal to 0.2 mm.

4. A low-carbon sludge solidifying agent according to claims 1-2, characterized in that: The fly ash must meet the standard of GB / T1596-2017 "Fly ash used in cement and concrete" Grade I or above.

5. A low-carbon sludge solidifying agent according to claims 1-2, characterized in that: The specific surface areas of the granulated fly ash and desulfurized gypsum slag are both greater than or equal to 400 m2 / kg, and the cement model is P.O42.

5.

6. A method for preparing a low-carbon sludge solidifying agent according to any one of claims 1 to 2, characterized in that: The specific steps include: S1. Calculate the amount of materials; calculate the mass of the sludge according to the sludge volume and density in the solidification area, and calculate the amount of each raw material of the solidifying agent according to the designed ratio; S2. Processing materials: drying, crushing and sieving loess, and ball-milling fly ash and desulfurization gypsum from power plants to target particle sizes; S3, stirring the mixed materials; according to the above-mentioned curing agent ratio, loess, fly ash, desulfurized gypsum and cement of corresponding mass are weighed and put into a mixing device according to the designed ratio, and then fully stirred to obtain a curing agent for curing the sludge.

7. The method for preparing a low-carbon sludge solidifying agent according to claim 6, characterized in that: In step S1, based on the mass of wet sludge, the initial moisture content of the wet sludge is 60%-70%, and the mass percentage of the curing agent is 30%-50%.

8. A preparation device for the low-carbon sludge solidifying agent according to claim 6, comprising a tank body (1), a telescopic rod (4), a motor (6), a stirring rod (7) and a stirring blade (8), characterized in that: The tank body (1) is provided with a cover plate (2) for moving and sealing the top opening of the tank body (1); a non-slip pad (3) for increasing the friction between the cover plate (2) and the tank body (1) is provided at the position where the cover plate (2) moves and contacts the tank body (1); a telescopic rod (4) is provided on the cover plate (2); a bracket (5) is provided on the telescopic rod (4); a stirring rod (7) is rotatably connected to the bracket (5); the bottom of the stirring rod (7) moves through the cover plate (2) and is connected to a stirring blade (8) for stirring materials.

9. The preparation device of a low-carbon sludge solidifying agent according to claim 8, characterized in that: The tank body (1) is a stirring tank body, the diameter of the through hole on the cover plate (2) penetrated by the stirring rod (7) is larger than the diameter of the stirring rod (7), and the anti-slip pad (3) is provided with two groups symmetrically arranged at the bottom of the cover plate (2) and the top of the tank body (1).

10. The preparation device of a low-carbon sludge solidifying agent according to claim 8, characterized in that: The bracket (5) is provided with a motor (6) for driving the stirring rod (7) to rotate, the driving end of the motor (6) is connected to the stirring rod (7), the minimum distance between the bracket (5) and the bottom of the tank body (1) is greater than the length of the stirring rod (7), and the maximum length of the telescopic rod (4) is less than the maximum distance between the stirring blade (8) and the cover plate (2).

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