CN113264734A - Sludge curing material based on cement-based carbon dioxide foam and sludge curing method and application thereof - Google Patents
Sludge curing material based on cement-based carbon dioxide foam and sludge curing method and application thereof Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
- C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
- C04B28/04—Portland cements
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- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B38/00—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof
- C04B38/10—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof by using foaming agents or by using mechanical means, e.g. adding preformed foam
- C04B38/103—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof by using foaming agents or by using mechanical means, e.g. adding preformed foam the foaming being obtained by the introduction of a gas other than untreated air, e.g. nitrogen
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
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- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
- C04B2111/00663—Uses not provided for elsewhere in C04B2111/00 as filling material for cavities or the like
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
- C04B2111/0075—Uses not provided for elsewhere in C04B2111/00 for road construction
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- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
- C04B2111/00767—Uses not provided for elsewhere in C04B2111/00 for waste stabilisation purposes
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- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2201/00—Mortars, concrete or artificial stone characterised by specific physical values
- C04B2201/20—Mortars, concrete or artificial stone characterised by specific physical values for the density
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- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2201/00—Mortars, concrete or artificial stone characterised by specific physical values
- C04B2201/50—Mortars, concrete or artificial stone characterised by specific physical values for the mechanical strength
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Abstract
The invention provides a sludge curing material based on cement-based carbon dioxide foam, which comprises the following components in percentage by mass: 23-37% of silt, 30-41% of fly ash and 31-36% of cement-based carbon dioxide foam; wherein, the 31-36% cement-based carbon dioxide foam comprises 20-25% cement, 0.7-0.9% foaming agent, 0.85-0.95% foam stabilizer and 8-12% water. The invention also discloses a sludge solidification method and application. The invention makes full use of the two sources causing two environmental problems at present, namely carbon dioxide greenhouse gas and dredging sludge in the lake and ocean, innovatively utilizes a foaming agent and a foam stabilizer to foam carbon dioxide, forms composite slurry with cement and fly ash, and uses the composite slurry as a curing agent to cure the dredging sludge.
Description
Technical Field
The invention relates to a sludge curing material based on cement-based carbon dioxide foam, a sludge curing method and application thereof, wherein the curing method combines the treatment of carbon dioxide greenhouse gas and dredged sludge, belongs to a novel sludge curing method which has important significance for the sustainable development of engineering materials and the relief of global climate change of greenhouse gas emission, and belongs to the technical field of sludge curing.
Background
With the rapid development of economic construction, global warming is gradually increased, mainly due to excessive emission of greenhouse gases such as carbon dioxide. Related weather and environmental scientists predict that for every 1-fold increase in atmospheric carbon dioxide content, global air temperature will rise on average by 1.5-4.5 ℃, while the average air temperature in the north and south regions is about 3 times the average air temperature, causing glaciers melting in the two polar regions, sea level rising, greenhouse effect and global warming to have attracted attention all over the world.
Secondly, dredged or seaside sludge belongs to solid waste, and if the dredged or seaside sludge can be used as a filling material in engineering, the dredged or seaside sludge can be changed into valuable, a large amount of waste is consumed, and meanwhile, the increasing demand on engineering filling materials is met. However, the sludge has high water content, high fine particle content and low shear strength, and the engineering can not be directly utilized. The chemical solidification method can improve the engineering property of the sludge to meet the engineering requirement, and is a method which is relatively accepted by the engineering and academic circles at home and abroad.
Today, CO is carried out by geological bonding, marine bonding, and the like2Isolation and sequestration is difficult to popularize, so CO is carried out by mineral carbonization, concrete carbonization and MgO carbonization2Isolation and sequestration is a viable alternative, and this patent contemplates the use of mineral carbonation for CO2And (5) isolating and sealing. Mineral carbonization is understood to mean the carbonization by CO2A carbon fixation method for forming stable carbonate by carbonization reaction with mineral or metal oxide rich in calcium/magnesium. Mineral carbonization is affected by the initial chemical composition, mineral characteristics in the cement and CO2The influence of absorption can be divided into natural carbonization and accelerated carbonization according to the carbonization speed: natural carbonization, also known as efflorescence, is atmospheric CO2The carbonization reaction with the base material is carried out, and the natural carbonization is slow for a long time; accelerated carbonation is a new carbonation technology, mostly realized by human factors, i.e. injecting high-purity CO into cement slurry2The carbonization can be completed within minutes or hours, and the early strength of the cement paste is improved.
Disclosure of Invention
The invention aims to solve the technical problem of providing a sludge curing material based on cement-based carbon dioxide foam, which has the advantages of small density, high strength, small compressibility, small permeability, good water stability, capability of achieving higher strength in a short time, good filling effect, greenness, environmental protection and cheap and easily-obtained raw materials.
Meanwhile, the invention provides a silt curing method based on cement-based carbon dioxide foam, which is simple to operate in site construction and is suitable for roadbed filling and backfilling of engineering sites.
Meanwhile, the invention provides a sludge curing material based on cement-based carbon dioxide foam for curing sea sludge and CO2Isolating applications in the package.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows:
a sludge curing material based on cement-based carbon dioxide foam comprises the following components in percentage by mass: 23-37% of silt, 30-41% of fly ash and 31-36% of cement-based carbon dioxide foam; the blending mass ratio of the sludge to the fly ash is 1: (0.81-0.85); wherein, the 31-36% cement-based carbon dioxide foam comprises 20-25% cement, 0.7-0.9% foaming agent, 0.85-0.95% foam stabilizer and 8-12% water.
The foaming agent is tea saponin, and the doping concentration of the foaming agent is 3.7-4.2 g/L.
The foam stabilizer is Sodium Dodecyl Benzene Sulfonate (SDBS), and the doping concentration of the foam stabilizer is 4.7-5.2 g/L.
The water content of the sludge is 46-63%.
The sludge comprises pretreated sea sludge, and the pretreatment method comprises the steps of carrying out refining treatment on the sea sludge through a filter screen, removing large-particle impurities and obtaining refined sea sludge; and further comprises treating the refined sea sludge through soaking treatment and/or an electrodialysis method to obtain desalinated sludge.
The large particle impurities include seashells and seaweeds.
A sludge curing method of a sludge curing material based on cement-based carbon dioxide foam comprises the following steps:
step one, preparing cement-based carbon dioxide foam:
stirring and blending a foaming agent and a foam stabilizer respectively at the concentration of 3.7-4.2g/L and 4.7-5.2g/L to prepare a premixed liquid, wherein the solvent is water, the premixed liquid passes through a water-based foam generating device, the pressure of the water-based foam generating device is 0.2-0.5MPa, carbon dioxide is used as a gas source for foaming, and the rotating speed of a high-pressure pump is more than 25r/s during foaming to generate carbon dioxide water-based foam;
stirring and blending cement and water according to a proper water-cement mass ratio to obtain cement slurry; mixing the prepared carbon dioxide water-based foam and cement slurry according to a certain proportion, wherein the volume ratio of the foam to the slurry is (4.2-5.2): 1,
stirring at the speed of 20-22r/min for 3-5min to obtain cement-based carbon dioxide foam;
and step two, firstly, mixing the sludge and the fly ash to form composite powder, then adding cement-based carbon dioxide foam, stirring and mixing, and then curing to form the sludge solidified material, wherein the stirring speed is 15-20r/min, and the stirring time is 3-5 min.
The ratio of the working rotating speed of the high-pressure pump to the maximum rotating speed of the high-pressure pump is 50-70%.
After the sludge solidified material is cured for 28 days, the density of the sludge solidified material is 1.337-1.359g/cm3The unconfined compressive strength is 1149.9-1205.1 kPa.
Silt curing material for curing sea silt and CO based on cement-based carbon dioxide foam2Isolating applications in the package.
After 7d of curing, the unconfined compressive strength of the sludge curing material can reach 70% of that after 28d of curing and 85% of that after 14d of curing.
The permeability coefficient of the sludge curing material can reach 10 after 7d curing-5In the order of cm/s.
The water stability coefficient of the sludge curing material, namely the ratio of unconfined compressive strength of a sample after soaking to unconfined compressive strength of the sample after soaking reaches more than 70%.
After the sludge solidification material is maintained for 14 days, compared with the common cement slurry with the same water-cement ratio, the sludge solidification material has the components of Ca (OH)2With CO2Formation of CaCO3About 26% increase in conversion.
After 14 days of curing, the internal friction angle of the sludge curing material reaches 45 degrees, and the cohesive force reaches 140 kPa.
Compared with the common silicate cement slurry solidified sludge, the sludge solidified material has the following beneficial effects:
(1) the invention fully utilizes two sources which cause two environmental problems at present, namely carbon dioxide greenhouse gas and dredged sediment in lakes and seas, and most domestic and foreign researches show that carbon dioxide can only carry out surface carbonization on sludge solidified materials in the curing process. The invention creatively utilizes the foaming agent and the foam stabilizer to foam carbon dioxide, and the carbon dioxide, the cement and the fly ash form composite slurry which is used as a curing agent and is used for curing dredged sludge. The method solves the problems that carbon dioxide can only carry out surface carbonization on the sludge curing material in the curing process and cannot greatly improve the early strength of the sludge curing material.
(2) From the viewpoint of construction, the method can shorten the curing time of the sludge to reach the on-site specified strength and greatly shorten the construction period by solidifying the dredged sludge by using the cement-based carbon dioxide foam.
(3) The invention considers the analysis of the environmental suitability of the improved soil body, such as the influence of the pH value of the improved soil body on the surrounding vegetation, namely the plantability of plants. The pH value of the sludge curing material is in the pH range of normal growth of common vegetation, and when the sludge curing material is used as an engineering filler, the sludge curing material has no influence on the growth of peripheral vegetation.
(4) The sludge curing material has the advantages of small density, high strength, small compressibility, small permeability and good water stability, can achieve higher strength in a short time, and has good filling effect.
(5) The main raw materials used by the invention are carbon dioxide greenhouse gas and dredged sludge, the materials are convenient to obtain, the cost is extremely low, the construction cost can be greatly reduced, and the ecological concept of environmental sustainable development is met.
Drawings
FIG. 1 is a sectional view of a sample of a sludge solidified material of the present invention having a size of 160mm by 40 mm;
FIG. 2 is a curve of the relationship between unconfined compressive strength of sludge solidifying materials of different ages and the mixing amount of cement-based carbon dioxide foam;
FIG. 3 is a curve of unconfined compressive strength versus age of a sludge curing material of different amounts of cement-based carbon dioxide foam in accordance with the present invention;
FIG. 4 is a graph showing the relationship between the internal friction angle of the sludge solidification material of different ages and the admixture amount of the cement-based carbon dioxide foam;
FIG. 5 is a graph showing the relationship between cohesion of sludge curing materials of different ages and the amount of carbon dioxide foam doped in cement base;
FIG. 6 is a graph showing the relationship between cohesion and age of a sludge solidifying material of different amounts of cement-based carbon dioxide foam according to the present invention;
FIG. 7 is a graph showing the relationship between the internal friction angle and age of a sludge-solidified material with different amounts of cement-based carbon dioxide foam according to the present invention;
FIG. 8 is a graph showing the relationship between the permeability coefficient of the sludge-solidified material and the amount of the cement-based carbon dioxide foam mixed after 7d curing according to the present invention;
FIG. 9 is a graph showing the relationship between the water stability factor of the sludge curing material of different ages and the admixture amount of the cement-based carbon dioxide foam according to the present invention;
FIG. 10 is a graph of water stability factor versus age for a sludge curing agent for different amounts of cement-based carbon dioxide foam in accordance with the present invention;
FIG. 11 is an electron microscope scanning microscopic optical image of a sludge solidified material of the present invention;
FIG. 12 is a graph of pH versus age for a cement-based carbon dioxide foam of the present invention;
FIG. 13 is a state diagram of the foaming agent tea saponin material of the present invention;
FIG. 14 is a state diagram of the raw material of sodium dodecylbenzenesulfonate as a foam stabilizer in accordance with the present invention.
FIG. 15 is a schematic structural view of the water-based foam generating apparatus of the present invention;
FIG. 16 is a state diagram of the presence of a cement-based carbon dioxide foam of the present invention;
FIG. 17 is a flow chart of a manufacturing process of the present invention.
Detailed Description
The sludge solidification material based on cement-based carbon dioxide foam, the sludge solidification method and the application thereof are further described in detail with reference to the accompanying drawings and specific examples.
Example 1
The foaming agent used in the test is tea saponin which is a common vegetable protein cement foaming agent on the market and is from industrial promotion chemical company Limited in Wuhanji, and the basic state of the foaming agent is shown in figure 13. The foam stabilizer adopts the common anion foam stabilizer sodium dodecyl benzene sulfonate on the market, is from Shanghai Kainen chemical company Limited, and the basic state of the foam stabilizer is shown in figure 14. The cement is ordinary Portland conch brand 42.5 cement, and the basic properties and the main component composition of the cement are shown in tables 1 and 2. The fly ash comes from a green Ming-sourced environment-friendly material factory and has the main component composition shown in Table 3. Sludge was collected from areas in Fujian province and soil samples were transported in double plastic bags to preserve the natural moisture content of the soil samples and prevent the effects of the dry-wet cycle on the soil properties. As the soil is necessarily disturbed to a large extent in the stages of bagging, storing and transporting, a sludge remolding sample is adopted in the test, and when the sludge solidifying material is used as an engineering filler, the sludge remolding sample has no influence on the soil sample, so that the growth of peripheral vegetation is not influenced.
Sludge treatment: impurities such as shells, seaweed and the like may exist in the sea sludge, and the liquid sludge is subjected to refining treatment through a filter screen; the desalting treatment in a laboratory can be realized by a soaking treatment and an electrodialysis method, and the desalting treatment can be realized by the electrodialysis method in engineering practice.
TABLE 1 test results of ordinary Portland 42.5 Cement Properties
TABLE 2 Laplace trumpet shell brand ordinary silicate 42.5 cement main chemical components and contents
Table 3 main chemical components and percentages (%)
As shown in fig. 17, in a method for curing sludge based on cement-based carbon dioxide foam, the basic preparation process of cement-based carbon dioxide foam can be divided into three parts, namely preparation of water-based foam, mixing and stirring of composite cement slurry, and mixing of water-based foam and composite cement slurry.
The foaming agent and the foam stabilizer are stirred and blended at the concentration of 4g/L and 5g/L respectively to prepare a premixed liquid, and the premixed liquid is foamed by a water-based foam generating device (shown in figure 15) by using carbon dioxide as a gas source to generate carbon dioxide water-based foam. Stirring and blending cement (21.45% of cement) and a certain amount of water (12% of water) in a proper water-cement ratio to obtain cement slurry, and mixing the prepared carbon dioxide water-based foam and the cement slurry in a certain ratio, wherein the foam-slurry volume ratio is 4.2: 1, the foam slurry volume ratio is the volume ratio of the carbon dioxide water-based foam to the cement slurry, stirring is carried out at a relatively slow speed of about 20r/min for about 3min, so as to avoid damaging the foam or accelerating the dissipation of foam liquid discharge at a too high speed, and obtain the cement-based carbon dioxide foam, which is specifically shown in fig. 16. In order to ensure the integrity and stability of foam in the foam cement slurry during stirring, the sludge is firstly blended with the fly ash to form composite powder, then the foam cement slurry (namely cement-based carbon dioxide foam) is added for stirring, the stirring speed during stirring is 15r/min, and the stirring time is 3min, so that the sludge curing material is obtained. The initial water content of the sludge is 63.26%, the mass fraction of the sludge is 35%, the mass fraction of the fly ash is 30%, and the mass fraction of the foamed cement paste (namely, cement-based carbon dioxide foam) is 35%. Controlling the relative rotation speed (inflation rate) of the high-pressure pump to be 70%, placing the molded product in a curing room for curing for 28d 24h after molding is completed, and carrying out unconfined compressive strength test, shear strength test, penetration test and water stability test after curing for 3d, 7d, 14d and 28 d.
The preparation method needs to strictly control the pressure of gas entering the water-based foam generating device, in the embodiment, the pressure of the water-based foam generating device is 0.2MPa, and the pressure and the rotating speed of a high-pressure pump in the water-based foam generating device and the rotating speed of stirring the water-based foam and cement paste are strictly controlled.
TABLE 4 statistics of test results
As shown in FIG. 1, the sludge curing material prepared in this example has abundant pores, and the lung cancer is 1.359g/cm after 28 days of maintenance3Although the density of the solidified material is low, the sludge solidified material obtained in the embodiment has rich pores and low density, but the sludge solidified material has high strength, and after 28 days of maintenance, the unconfined compressive strength can reach 1205.1 kPa.
As shown in FIG. 2, the relationship curve between unconfined compressive strength of the sludge solidifying material of different ages and the mixing amount of the cement-based carbon dioxide foam is shown. As can be seen from FIG. 2, when the amount of the cement-based carbon dioxide foam is within the range of 31-36%, the unconfined compressive strength can reach about 1200kPa, and when the amount of the cement-based carbon dioxide foam is continuously increased, the change of the unconfined compressive strength tends to be smooth.
As shown in FIG. 3, it is a curve of unconfined compressive strength and age of the sludge solidifying material of different amounts of cement-based carbon dioxide foam. As can be seen from FIG. 3, when 25 to 50 percent of cement-based carbon dioxide foam is added, the variation range of the unconfined compressive strength is not large, and the unconfined compressive strength of the sludge curing material can reach 70 percent of that after being cured for 28 days and 85 percent of that after being cured for 14 days after being cured for 7 days. Therefore, the invention can reach higher strength in a short time, has good filling effect, is green and environment-friendly, has cheap and easily-obtained raw materials, can shorten the curing time for the sludge to reach the on-site specified strength, and greatly shortens the construction period.
FIG. 4 shows the relationship between the internal friction angle of the sludge solidification material of different ages and the mixing amount of the cement-based carbon dioxide foam. FIG. 5 shows the relationship between cohesion of sludge solidifying material of different ages and the amount of carbon dioxide foam in cement base. As can be seen from FIGS. 4 and 5, the internal friction angle of the sludge solidified material of the present invention after 14d curing reaches 45 degrees, and the cohesive force reaches 140 kPa.
FIG. 6 shows the relationship between cohesion and age of the sludge solidifying material of the cement-based carbon dioxide foam with different mixing amounts according to the present invention. FIG. 7 shows the relationship between the internal friction angle and age of the sludge solidification material with different amounts of the cement-based carbon dioxide foam according to the present invention. FIG. 8 shows a curve of the permeability coefficient of the sludge-solidified material after 7 days of curing according to the present invention, as a function of the amount of the cement-based carbon dioxide foam. Therefore, the permeability coefficient of the sludge curing material can reach 10 after 7d curing- 5cm/s order of magnitude and low permeability.
FIG. 9 shows the water stability factor of the sludge curing material of different ages as a function of the admixture amount of the cement-based carbon dioxide foam. FIG. 10 is a graph showing the relationship between water stability factor and age of the sludge solidifying material of different amounts of the cement-based carbon dioxide foam according to the present invention. Therefore, the water stability coefficient of the sludge curing material, namely the ratio of the unconfined compressive strength of the immersed sample to the unconfined compressive strength of the immersed sample reaches more than 70 percent, and the water stability is good.
FIG. 11 shows an electron microscopic optical image of the solidified sludge material of the present invention. Wherein, the first is a net structure formed by rod-shaped or whisker-shaped calcium vanadium stone, and sludge particles such as sludge, fly ash, cement products and the like are wrapped in the net structure. Secondly, CHS gel on the surface of the silt solidified material, which is an active ingredient contained in the fly ash and a product Ca (OH) capable of hydrating with early-stage cement2The secondary hydration reaction occurs. Thirdly, the sludge solidifying material surface granular cluster is cement hydration product CaCO3. Fourthly, cracks are generated around the pores due to dehydration when the sludge solidification material is hydrated.
FIG. 12 is a graph of pH versus age for a cement-based carbon dioxide foam of the present invention; therefore, the pH value of the sludge solidifying material is in the pH range of normal growth of common vegetation, and when the sludge solidifying material is used as an engineering filler, the sludge solidifying material has no influence on the growth of peripheral vegetation.
A sludge curing material based on cement-based carbon dioxide foam comprises the following components in percentage by mass: 35% sludge, 30% fly ash and 35% cement-based carbon dioxide foam; the blending mass ratio of the sludge to the fly ash is 1: 0.85; wherein, the 35% cement-based carbon dioxide foam comprises 21.45% of cement, 0.7% of foaming agent, 0.85% of foam stabilizer and 12% of water.
Silt curing material for curing sea silt and CO based on cement-based carbon dioxide foam2Isolating applications in the package.
Example 2
This example differs from example 1 only in that: the initial water content of the sludge is 63.26%, the mass fraction of the sludge is 37%, the mass fraction of the fly ash is 30%, and the mass fraction of the foamed cement paste is 33%. Controlling the relative rotation speed (inflation rate) of the high-pressure pump to be 70%, putting the molded product into a curing room for curing for 28d 24h after molding, and carrying out unconfined compression test, shear strength, penetration test and water stability test determination after curing for 3d, 7d, 14d and 28 d.
TABLE 5 statistics of test results
A sludge curing material based on cement-based carbon dioxide foam comprises the following components in percentage by mass: 37% sludge, 30% fly ash and 33% cement-based carbon dioxide foam; the blending mass ratio of the sludge to the fly ash is 1: 0.81; wherein, the 33% cement-based carbon dioxide foam comprises 23.15% of cement, 0.9% of foaming agent, 0.95% of foam stabilizer and 8% of water. Example 3
A sludge curing material based on cement-based carbon dioxide foam comprises the following components in percentage by mass: 23% sludge, 41% fly ash and 36% cement-based carbon dioxide foam; the blending mass ratio of the sludge to the fly ash is 1: 1.78; wherein, the 36% cement-based carbon dioxide foam comprises 25% of cement, 0.8% of foaming agent, 0.9% of foam stabilizer and 9.3% of water.
The foaming agent is tea saponin, and the doping concentration of the foaming agent is 3.7 g/L.
The foam stabilizer is Sodium Dodecyl Benzene Sulfonate (SDBS), and the doping concentration of the foam stabilizer is 4.7 g/L.
The moisture content of the sludge was 46%.
The sludge comprises pretreated sea sludge, and the pretreatment method comprises the steps of carrying out refining treatment on the sea sludge through a filter screen, removing large-particle impurities and obtaining refined sea sludge; and further comprises treating the refined sea sludge through soaking treatment and/or an electrodialysis method to obtain desalinated sludge.
The large particle impurities include seashells and seaweeds.
A method for curing sludge based on cement-based carbon dioxide foam, comprising the steps of:
step one, preparing cement-based carbon dioxide foam:
stirring and blending a foaming agent and a foam stabilizer at the concentrations of 3.7g/L and 4.7g/L respectively to prepare a premixed liquid, wherein the solvent is water, the premixed liquid passes through a water-based foam generating device, the pressure of the water-based foam generating device is 0.5MPa, carbon dioxide is used as a gas source for foaming, and the rotating speed of a high-pressure pump is 25r/s during foaming to generate carbon dioxide water-based foam;
stirring and blending cement and water according to a proper water-cement mass ratio to obtain cement slurry; mixing the prepared carbon dioxide water-based foam and cement slurry according to a certain proportion, wherein the volume ratio of the foam to the cement slurry is 5.2: 1,
stirring at the speed of 22r/min for 5min to obtain cement-based carbon dioxide foam;
and step two, firstly, mixing the sludge with the fly ash to form composite powder, then adding cement-based carbon dioxide foam, stirring and mixing, and then maintaining to form the sludge solidified material, wherein the stirring speed is 20r/min, and the stirring time is 5 min.
TABLE 6 statistics of test results
Example 4
A sludge curing material based on cement-based carbon dioxide foam comprises the following components in percentage by mass: 28% sludge, 41% fly ash and 31% cement-based carbon dioxide foam; the blending mass ratio of the sludge to the fly ash is 1: 1.46; wherein, the 31% cement-based carbon dioxide foam comprises 20% of cement, 0.7% of foaming agent, 0.85% of foam stabilizer and 9.45% of water.
The foaming agent is tea saponin, and the doping concentration of the foaming agent is 4.2 g/L.
The foam stabilizer is Sodium Dodecyl Benzene Sulfonate (SDBS), and the doping concentration of the foam stabilizer is 5.2 g/L.
The moisture content of the sludge is 55%.
The sludge comprises pretreated sea sludge, and the pretreatment method comprises the steps of carrying out refining treatment on the sea sludge through a filter screen, removing large-particle impurities and obtaining refined sea sludge; and further comprises treating the refined sea sludge through soaking treatment and/or an electrodialysis method to obtain desalinated sludge.
The large particle impurities include seashells and seaweeds.
A method for curing sludge based on cement-based carbon dioxide foam, comprising the steps of:
step one, preparing cement-based carbon dioxide foam:
stirring and blending a foaming agent and a foam stabilizer at the concentrations of 4.2g/L and 5.2g/L respectively to prepare a premixed liquid, wherein the solvent is water, the premixed liquid passes through a water-based foam generating device, the pressure of the water-based foam generating device is 0.3MPa, carbon dioxide is used as a gas source for foaming, the relative rotating speed of a high-pressure pump is 50% during foaming, and carbon dioxide water-based foam is generated;
stirring and blending cement and water according to a proper water-cement mass ratio to obtain cement slurry; mixing the prepared carbon dioxide water-based foam and cement slurry according to a certain proportion, wherein the weight ratio of the carbon dioxide water-based foam to the cement slurry is 5.0: 1,
stirring at the speed of 21r/min for 4min to obtain cement-based carbon dioxide foam;
and step two, firstly, mixing the sludge with the fly ash to form composite powder, then adding cement-based carbon dioxide foam, stirring and mixing, and then maintaining to form the sludge solidified material, wherein the stirring speed is 18r/min, and the stirring time is 4min, so that the sludge solidified material is obtained.
TABLE 7 statistics of test results
While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this description, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as described herein. Furthermore, it should be noted that the language used in the specification has been principally selected for readability and instructional purposes, and may not have been selected to delineate or circumscribe the inventive subject matter. Accordingly, many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the appended claims. The present invention has been disclosed in an illustrative rather than a restrictive sense, and the scope of the present invention is defined by the appended claims.
The above description is only of the preferred embodiments of the present invention, and it should be noted that: it will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the principles of the invention and these are intended to be within the scope of the invention.
Claims (10)
1. A sludge curing material based on cement-based carbon dioxide foam is characterized by comprising the following components in percentage by mass: 23-37% of silt, 30-41% of fly ash and 31-36% of cement-based carbon dioxide foam; the blending mass ratio of the sludge to the fly ash is 1: (0.81-0.85); wherein, the 31-36% cement-based carbon dioxide foam comprises 20-25% cement, 0.7-0.9% foaming agent, 0.85-0.95% foam stabilizer and 8-12% water.
2. The sludge curing material based on the cement-based carbon dioxide foam as claimed in claim 1, wherein the foaming agent is tea saponin, and the mixing concentration of the foaming agent is 3.7-4.2 g/L.
3. The sludge curing material based on the cement-based carbon dioxide foam as claimed in claim 1, wherein the foam stabilizer is Sodium Dodecyl Benzene Sulfonate (SDBS), and the mixing concentration of the foam stabilizer is 4.7-5.2 g/L.
4. The cement-based carbon dioxide foam-based sludge solidification material as claimed in claim 1, wherein the water content of the sludge is 46-63%.
5. The sludge solidification material based on the cement-based carbon dioxide foam as claimed in claim 1, wherein the sludge comprises pretreated sea sludge, and the pretreatment method comprises refining the sea sludge through a filter screen to remove large granular impurities and obtain refined sea sludge; and further comprises treating the refined sea sludge through soaking treatment and/or an electrodialysis method to obtain desalinated sludge.
6. The cement-based carbon dioxide foam-based sludge solidification material as claimed in claim 5, wherein the large-particle impurities comprise shells and seaweeds.
7. The method for curing the sludge based on the sludge curing material of the cement-based carbon dioxide foam as claimed in any one of claims 1 to 6, which is characterized by comprising the following steps:
step one, preparing cement-based carbon dioxide foam:
stirring and blending a foaming agent and a foam stabilizer respectively at the concentration of 3.7-4.2g/L and 4.7-5.2g/L to prepare a premixed liquid, wherein the solvent is water, the premixed liquid passes through a water-based foam generating device, the pressure of the water-based foam generating device is 0.2-0.5MPa, carbon dioxide is used as a gas source for foaming, and the rotating speed of a high-pressure pump is more than 25r/s during foaming to generate carbon dioxide water-based foam;
stirring and blending cement and water according to a proper water-cement mass ratio to obtain cement slurry; mixing the prepared carbon dioxide water-based foam and cement slurry according to a certain proportion, wherein the volume ratio of the foam to the slurry is (4.2-5.2): 1,
stirring at the speed of 20-22r/min for 3-5min to obtain cement-based carbon dioxide foam;
and step two, firstly, mixing the sludge and the fly ash to form composite powder, then adding cement-based carbon dioxide foam, stirring and mixing, and then curing to form the sludge solidified material, wherein the stirring speed is 15-20r/min, and the stirring time is 3-5 min.
8. The method of claim 7, wherein the ratio of the operating speed of the high pressure pump to the maximum speed of the high pressure pump is 50 to 70%.
9. The sludge solidification method as claimed in claim 7 or 8, wherein the sludge solidified material has a density of 1.337-1.359g/cm after being cured for 28 days3The unconfined compressive strength is 1149.9-1205.1 kPa.
10. The method for curing sludge curing material based on cement-based carbon dioxide foam and CO in sea sludge according to any one of claims 1 to 62Isolating applications in the package.
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