CN117700195A - Method for drying and solidifying flow-shaped sludge by phosphogypsum base powder - Google Patents
Method for drying and solidifying flow-shaped sludge by phosphogypsum base powder Download PDFInfo
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- CN117700195A CN117700195A CN202311837332.0A CN202311837332A CN117700195A CN 117700195 A CN117700195 A CN 117700195A CN 202311837332 A CN202311837332 A CN 202311837332A CN 117700195 A CN117700195 A CN 117700195A
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- 239000010802 sludge Substances 0.000 title claims abstract description 117
- PASHVRUKOFIRIK-UHFFFAOYSA-L calcium sulfate dihydrate Chemical compound O.O.[Ca+2].[O-]S([O-])(=O)=O PASHVRUKOFIRIK-UHFFFAOYSA-L 0.000 title claims abstract description 89
- 239000000843 powder Substances 0.000 title claims abstract description 52
- 238000000034 method Methods 0.000 title claims abstract description 40
- 238000001035 drying Methods 0.000 title claims abstract description 26
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 77
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 37
- 239000004568 cement Substances 0.000 claims abstract description 22
- 239000002893 slag Substances 0.000 claims abstract description 21
- 238000002156 mixing Methods 0.000 claims abstract description 19
- 239000004745 nonwoven fabric Substances 0.000 claims abstract description 16
- 238000007711 solidification Methods 0.000 claims abstract description 7
- 230000008023 solidification Effects 0.000 claims abstract description 7
- 238000004806 packaging method and process Methods 0.000 claims abstract description 5
- 239000012530 fluid Substances 0.000 claims description 9
- 239000002002 slurry Substances 0.000 claims 1
- 240000002853 Nelumbo nucifera Species 0.000 abstract description 44
- 235000006508 Nelumbo nucifera Nutrition 0.000 abstract description 44
- 235000006510 Nelumbo pentapetala Nutrition 0.000 abstract description 42
- 230000000694 effects Effects 0.000 abstract description 8
- 239000002699 waste material Substances 0.000 abstract description 8
- 230000008569 process Effects 0.000 abstract description 7
- 238000011049 filling Methods 0.000 abstract description 5
- 238000005265 energy consumption Methods 0.000 abstract description 2
- 238000011065 in-situ storage Methods 0.000 abstract description 2
- 239000007943 implant Substances 0.000 abstract 1
- 238000010521 absorption reaction Methods 0.000 description 26
- 239000003344 environmental pollutant Substances 0.000 description 10
- 231100000719 pollutant Toxicity 0.000 description 10
- 239000000203 mixture Substances 0.000 description 7
- 239000000126 substance Substances 0.000 description 7
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 6
- 238000003756 stirring Methods 0.000 description 6
- 230000006835 compression Effects 0.000 description 5
- 238000007906 compression Methods 0.000 description 5
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 4
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 description 4
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 4
- 229910052731 fluorine Inorganic materials 0.000 description 4
- 239000011737 fluorine Substances 0.000 description 4
- 229910001385 heavy metal Inorganic materials 0.000 description 4
- 239000011574 phosphorus Substances 0.000 description 4
- 229910052698 phosphorus Inorganic materials 0.000 description 4
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 3
- 230000018044 dehydration Effects 0.000 description 3
- 238000006297 dehydration reaction Methods 0.000 description 3
- 239000010813 municipal solid waste Substances 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 238000004064 recycling Methods 0.000 description 3
- 229920000742 Cotton Polymers 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 230000000996 additive effect Effects 0.000 description 2
- 239000002956 ash Substances 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 239000000292 calcium oxide Substances 0.000 description 2
- 235000012255 calcium oxide Nutrition 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 238000003912 environmental pollution Methods 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 239000004744 fabric Substances 0.000 description 2
- 238000007731 hot pressing Methods 0.000 description 2
- 230000008595 infiltration Effects 0.000 description 2
- 238000001764 infiltration Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000012856 packing Methods 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 238000007789 sealing Methods 0.000 description 2
- 239000002689 soil Substances 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 238000003860 storage Methods 0.000 description 2
- 239000010902 straw Substances 0.000 description 2
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 1
- 235000019738 Limestone Nutrition 0.000 description 1
- 239000011398 Portland cement Substances 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Inorganic materials [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 239000010881 fly ash Substances 0.000 description 1
- 238000001879 gelation Methods 0.000 description 1
- 239000001866 hydroxypropyl methyl cellulose Substances 0.000 description 1
- 229920003088 hydroxypropyl methyl cellulose Polymers 0.000 description 1
- UFVKGYZPFZQRLF-UHFFFAOYSA-N hydroxypropyl methyl cellulose Chemical compound OC1C(O)C(OC)OC(CO)C1OC1C(O)C(O)C(OC2C(C(O)C(OC3C(C(O)C(O)C(CO)O3)O)C(CO)O2)O)C(CO)O1 UFVKGYZPFZQRLF-UHFFFAOYSA-N 0.000 description 1
- 235000010979 hydroxypropyl methyl cellulose Nutrition 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 239000006028 limestone Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 239000002686 phosphate fertilizer Substances 0.000 description 1
- 229920001495 poly(sodium acrylate) polymer Polymers 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000011435 rock Substances 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 230000035943 smell Effects 0.000 description 1
- NNMHYFLPFNGQFZ-UHFFFAOYSA-M sodium polyacrylate Chemical compound [Na+].[O-]C(=O)C=C NNMHYFLPFNGQFZ-UHFFFAOYSA-M 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000002910 solid waste Substances 0.000 description 1
- 238000009270 solid waste treatment Methods 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000008832 zhongfu Substances 0.000 description 1
Classifications
-
- 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
- C04B28/14—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 calcium sulfate cements
- C04B28/142—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 calcium sulfate cements containing synthetic or waste calcium sulfate cements
- C04B28/143—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 calcium sulfate cements containing synthetic or waste calcium sulfate cements the synthetic calcium sulfate being phosphogypsum
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F11/00—Treatment of sludge; Devices therefor
- C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
- C02F11/14—Treatment of sludge; Devices therefor by de-watering, drying or thickening with addition of chemical agents
- C02F11/143—Treatment of sludge; Devices therefor by de-watering, drying or thickening with addition of chemical agents using inorganic substances
-
- 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
- C04B2111/00767—Uses not provided for elsewhere in C04B2111/00 for waste stabilisation purposes
-
- 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
- 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
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/91—Use of waste materials as fillers for mortars or concrete
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Ceramic Engineering (AREA)
- Organic Chemistry (AREA)
- Environmental & Geological Engineering (AREA)
- Hydrology & Water Resources (AREA)
- Water Supply & Treatment (AREA)
- Life Sciences & Earth Sciences (AREA)
- Inorganic Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Treatment Of Sludge (AREA)
Abstract
The invention discloses a method for drying and solidifying phosphogypsum base powder into flowing plastic sludge, which comprises the steps of preparing a solidifying agent and phosphogypsum base powder by using phosphogypsum, slag and cement respectively, quantitatively filling the phosphogypsum base powder into non-woven fabrics, and packaging the phosphogypsum base powder into strip-shaped members similar to lotus node sections; and uniformly mixing the fluid-plastic sludge with a curing agent to obtain cured sludge, and then implanting strip-shaped components containing phosphogypsum base powder into the cured sludge for curing and curing. The invention relatively separates the drying process and the curing process of the flowing plastic sludge, firstly mixes the flowing plastic sludge with the curing agent, and utilizes the strength increasing rule of the curing agent of 'slow first and fast second', and immediately implants the strip-shaped component containing phosphogypsum base powder after mixing, absorbs free water, and dries and cures. The invention reduces the negative effect of high water content of the sludge, eliminates a large amount of phosphogypsum, realizes the in-situ solidification of the sludge with low energy consumption, improves the integral strength of the sludge, and achieves the purpose of treating waste by waste.
Description
Technical Field
The invention belongs to the technical field of environmental geotechnical-solid waste treatment, and particularly relates to a method for drying and solidifying flow-shaped sludge by phosphogypsum base powder.
Background
The dredging sludge is waste in the ecological environment treatment process of rivers and lakes, has black color, smells and malodors, and also contains heavy metal pollutants. For a long time, offshore dumping and land stacking are main methods for treating sludge, and the methods such as stacking and landfill occupy a large amount of land resources and have potential risks of environmental pollution. In order to prevent the water environment from being increasingly worsened, the drainage and storage capacity is improved, dredging sludge is scientifically treated, and the sludge recycling is a key problem to be solved urgently. Currently, two major approaches to solidifying sludge are: (1) the mud-water separation is realized by vacuum preloading and other methods; (2) the sludge is cured by an organic (inorganic) cement.
The method for solidifying the sludge usually adopts a cement solidification method, but the water content of the produced sludge after the dredging construction is finished is 2-3 times or even higher than the liquid limit of the original sludge in China by adopting a hydraulic dredging mode, so that the cost for treating the high-water-content dredging sludge by adopting cement solidification is too high, and the popularization and application of the cement solidification method are seriously limited.
Chinese patent CN102173695A discloses a novel additive of a high-water-content dredging sludge composite curing material, which is a composite additive formed by cement, quicklime and sodium polyacrylate, solves the problem of rapid curing treatment of the high-water-content dredging sludge, and can obviously improve the soil strength. Chinese patent CN114149202A discloses a curing agent for dredging sludge with high water content, a preparation method and application thereof, wherein garbage incineration bottom slag and garbage incineration bottom slag are ground into fine powder to obtain garbage incineration bottom slag mixture, straw ash and industrial steel slag are mixed and ball-milled to obtain a mixture of straw ash ground fine powder and industrial steel slag ground fine powder, and finally all raw materials are mixed according to a proportion to prepare the curing agent, so that the dredging sludge can be effectively cured, the water content of the dredging sludge is reduced, the low-strength characteristic of the dredging sludge is improved, the dredging sludge can be used as a filling material after curing treatment, and the purposes of treating waste with waste and protecting environment are realized.
Phosphogypsum is a solid waste generated in the wet-process phosphoric acid process, and the component of phosphogypsum is mainly calcium sulfate dihydrate. Phosphogypsum has complex composition, and besides calcium sulfate, phosphorus ore which is not completely decomposed, residual phosphoric acid, fluoride, acid insoluble substances, organic matters and the like, wherein the presence of fluorine and organic matters has the greatest influence on the recycling of phosphogypsum. The random discharge and accumulation of phosphogypsum seriously damages the ecological environment, not only pollutes the underground water resource, but also causes the waste of land resource. The random accumulation and discharge of phosphogypsum restricts the sustainable development of industries such as wet phosphoric acid, phosphate fertilizer and the like, so that the treatment and recycling of phosphogypsum are an urgent problem. Phosphogypsum is mainly applied to various aspects such as agriculture, industry, building field and the like. But the phosphogypsum storage amount of China is still higher up to the present, and the comprehensive utilization is insufficient.
Chinese patent CN106478012a discloses a sludge curing agent and a preparation method thereof, wherein phosphogypsum, cement, quicklime, limestone, fly ash, hydroxypropyl methylcellulose, cast stone powder, ceramic micropowder and other substances are mixed to obtain the sludge curing agent, which can remarkably reduce the water content of sludge, reduce the internal strain of the sludge after curing and prevent cracking. Ding Jianwen on the basis of the traditional cement curing sludge, a method for curing the high-water-content dredging sludge by cement-phosphogypsum double-doping curing is proposed (Ding Jianwen, zhang Shuai, hong Zhenshun and the like, experimental research on the high-water-content dredging sludge by cement-phosphogypsum double-doping curing, and rock and soil mechanics, 2010, 31 (9): 2817-2822).
However, the dredging sludge has high water content, and the conventional curing agent cannot achieve a good curing effect, so that the conventional curing agent is often matched with a drying technology, such as natural drying, mechanical dehydration, vacuum preloading dehydration and the like, but the conventional drying technology takes effect slowly, requires large-scale dehydration equipment or more complex construction, is difficult to satisfy the drying of a large amount of dredging sludge, and heavy metal pollutants contained in the dredging sludge have the risk of secondary environmental pollution in the drying process. Therefore, a method for reducing the water content of dredging sludge, improving the curing effect and absorbing a large amount of phosphogypsum is necessary to be developed.
Disclosure of Invention
Aiming at the technical problems, the invention provides a method for drying and curing flowing plastic sludge by phosphogypsum base powder, which uses the strength increase rule of phosphogypsum base curing agent ('firstly slow and secondly fast') to skillfully change the defects of phosphogypsum base curing agent into advantages, provides plentiful time for free water absorption of lotus node structure, realizes the mode of 'firstly absorbing water and then curing' of phosphogypsum base powder, avoids the effect of curing agent on sludge due to high water content, thereby improving the strength of curing sludge and realizing efficient and low-energy consumption in-situ curing of sludge.
In order to achieve the above purpose, the invention provides a method for drying and curing fluid plastic sludge by phosphogypsum base powder, which comprises the following steps:
(1) Preparing phosphogypsum base powder, and packaging in sections to prepare strip-shaped components;
(2) Mixing phosphogypsum, slag and cement to prepare a curing agent;
(3) Uniformly mixing a curing agent with the sludge to obtain cured sludge;
(4) And (3) implanting the strip-shaped members into the solidified sludge, and curing and solidifying.
Preferably, the phosphogypsum base powder in the step (1) is prepared from phosphogypsum, slag and cement according to the mass ratio of 50-80:45-15:5, preferably 70:25:5.
preferably, the strip-shaped member in the step (1) is formed by packing non-woven fabrics in sections, and each section is approximately spherical.
Further preferably, the nonwoven fabric has a mass per unit area of 15-25g/m 2 Radius of each section1-3cm.
Further, the distance between each two sections is 0-13cm, and the mass of each section is 30-100g; the preferred spacing per section is 8-13cm, with a mass per section of 50g.
Preferably, the mass ratio of phosphogypsum, slag and cement in the step (2) is 15-35:65-80:5.
preferably, the curing agent in the step (3) is used in an amount of 20-40% of the mass of the sludge.
Further preferably, the water content of the sludge is 120% -200%.
Preferably, the distance between the strip-shaped members in the step (4) is 8-13cm.
Further preferably, the distance between each of the strip members is 9.6cm.
The invention has the beneficial effects that:
1. mixing a curing agent with the flowing plastic sludge, implanting strip-shaped members similar to lotus node containing phosphogypsum base powder into the curing sludge in the early stage of curing, absorbing free water in the curing sludge by utilizing the strength increasing rule of the phosphogypsum base curing agent of slow first and fast second, drying the sludge and then curing the sludge, thereby solving the problem of insufficient curing strength of the sludge due to high water content of the sludge and reducing the negative benefit of high water content of the sludge.
2. Packaging phosphogypsum base powder into strip-shaped members similar to lotus node by using non-woven fabrics, forming a solidified body after the phosphogypsum base powder absorbs free water, and improving the pulling resistance after the whole sludge is solidified, thereby playing a role in improving the whole strength of the sludge; meanwhile, free water in the sludge absorbed by the phosphogypsum base powder can fix heavy metal pollutants in the sludge and phosphorus, fluorine and other pollutants in phosphogypsum, so that secondary pollution of the pollutants to the environment caused by outflow of the pollutants along with water is avoided.
3. The curing agent is prepared by using phosphogypsum with lower content, and phosphogypsum base powder is prepared by using phosphogypsum with higher content, so that a large amount of phosphogypsum is consumed in the curing process of the flowing plastic sludge, the curing cost is reduced, the application scene of phosphogypsum is expanded, and the waste is treated by waste.
4. The strip-shaped components are packaged by using non-woven fabrics, so that a channel which oozes out to the outer surface is provided for free water in the sludge, and the rapid evaporation of the free water is facilitated.
Drawings
FIG. 1 is a bar graph of curing age and compressive strength of the curing agent of example 1.
FIG. 2 is a schematic structural view of a bar-shaped member similar to "lotus node" in embodiment 2; in the figure, 1 is non-woven fabric, 2 is sleeve, and 3 is phosphogypsum base powder.
Fig. 3 is a schematic drawing showing the binding of the bar-shaped member in example 2.
FIG. 4 is a flow chart of parameter determination and water absorption of the individual "lotus node" in examples 2 and 3, wherein A is the strip-shaped member prepared in example 1, and B is the water absorption experiment of the "lotus node" with different radii in example 1; c is a water absorption experimental diagram of a single lotus node in sludge in the embodiment 2, and D is phosphogypsum base powder which is gel after water absorption.
FIG. 5 is a cross-sectional view of the water absorption radius of the bar-like member of example 4, wherein 1 is a solid "lotus node" formed after the phosphogypsum-based powder absorbs water.
Fig. 6 is a schematic view of the shape of the guide bar in embodiment 5.
Detailed Description
The technical solution of the present invention will be further explained below with reference to the accompanying drawings and specific embodiments, and it should be noted that the following embodiments are only preferred embodiments of the present invention, and should not be construed as limiting the present invention, and the scope of the present invention shall be defined by the claims. Modifications and substitutions made by those skilled in the art without the inventive effort fall within the scope of the present invention.
In the examples below, phosphogypsum (RPG) was purchased from Zhongfu chemical company, inc., particle size 1.38-296 μm, and its chemical composition is shown in Table 1;
slag (GBS) purchased to Hubei Hongkan environmental protection building materials Co., ltd, particle size of 0.97-25 μm, and chemical composition shown in Table 1;
the cement was Ordinary Portland Cement (OPC) of PO42.5, and the chemical composition thereof is shown in Table 1.
TABLE 1 chemical composition of raw materials (wt%)
EXAMPLE 1 investigation of the law of increase in Strength after curing
(1) Phosphogypsum, slag and cement are mixed according to different mass ratios to prepare curing agents with different proportions (Table 2);
(2) And mixing the curing agent with the dredging sludge, uniformly stirring to obtain cured sludge, curing and curing at room temperature, and detecting the compressive strength of the sludge after curing for different times.
TABLE 2 raw material ratio of curing agent
As shown in FIG. 1, the compression strength of the sludge gradually rises along with the extension of the curing time, wherein when different curing agents are cured for 7 days, the compression strength of the sludge is about 14MPa, and the compression strength of the sludge after curing for 28 days obviously rises, so that the compression strength of the dredged sludge and the curing agents are mixed, and the compression strength of the dredged sludge has a 'quick-before-slow' growth rule.
EXAMPLE 2 determination of the radius and Mass of the individual "nodes
(1) Phosphogypsum, slag and cement are mixed according to the mass ratio of 70:25:5, uniformly mixing to prepare phosphogypsum base powder;
(2) The mass per unit area is 20g/m 2 Cutting the non-woven fabric into a rectangle with the width of 4 pi cm and the continuous length, and continuously hot-pressing and edge-sealing along the long side to prepare a sleeve with the radius of 2cm;
(3) Filling phosphogypsum base powder into a non-woven fabric sleeve by using a feeder, forming strip-shaped members (shown in figures 2-3) similar to lotus node by tying knots every 2, 4 and 6cm, and dispersing the strip-shaped members into single lotus node, wherein the radius of the corresponding single lotus node is 1cm, 2cm and 3cm, and the mass of the corresponding single lotus node is 30g, 50g and 100g;
(4) And (3) placing the single lotus node components with different qualities obtained in the step (3) into water or flowing plastic sludge (the water content is 125%) with 300mL respectively, stirring and mixing to enable the single lotus node to be completely immersed, counting the time of phosphogypsum integral complete water absorption infiltration in the single lotus node, and calculating the water content of the single lotus node after water absorption infiltration (figures 4A and B).
Table 3 quality and moisture content of lotus node before and after water absorption
The result shows that the quality of a single lotus node is not changed after 30 minutes in the flowing plastic sludge, and the phosphogypsum base powder is uniformly and fully soaked in water to reach a saturated state; when the radius of each single lotus node is 2cm and the mass is 50g, the mass after water absorption is 81.05g, the water content is 62.1%, and the optimal radius of each single lotus node is 2cm and the optimal mass is 50g. The phosphogypsum-based powder is packaged into lotus node shape in sections, can absorb free water, and has the potential of drying the flow plastic sludge.
Example 3
(1) A single "lotus node" with a radius of 2cm and a mass of 50g was prepared as described in example 1;
(2) Phosphogypsum, slag and cement are mixed according to the mass ratio of 25:75:5, uniformly mixing to obtain a curing agent;
(3) Detecting the water content of the dredged silt, mixing the silt with a curing agent, and uniformly stirring to obtain cured silt (figure 4C); wherein the dosage of the curing agent is 30% of the mass of the sludge;
(4) Mixing the single lotus node obtained in the step (1) and the solidified sludge obtained in the step (3) by stirring with a stirrer to ensure that the single lotus node is distributed in a dot shape in the solidified sludge, and absorbing free water in the solidified sludge by using phosphogypsum base powder contained in the single lotus node; wherein the water absorption thickness of the lotus node is 4.8cm, and the unit water absorption volume range is 58cm 3 ；
(5) Curing the solidified sludge containing single lotus node at room temperature, taking out after 30min to observe the gelation condition of phosphogypsum base powder (figure 4D), and detecting the compressive strength after 28D of solidification.
Results: after 30min, taking out the single lotus node, counting the mass after water absorption, and calculating to obtain the average water absorption of the single lotus node as 64.5%, wherein the curing effect is shown in Table 3.
TABLE 4 influence of the addition of "lotus node" on the curing effect of sludge
EXAMPLE 4 "lotus node" Water absorption area and thickness
(1) Water absorption area of a single "lotus node": taking a single-node lotus node with the mass of 50g as an example, experiments show that the water absorption mode of the single-node lotus node component takes the center of a circle as a center point, and the water absorption is diffused outwards on a plane by a radius; and the phosphogypsum-based powder is adsorbed with water in the sludge, so it is assumed that；
The volume of the dried sludge is；
The water absorption radius is；
The water absorption area is(FIG. 5);
(2) The sample cured with a single "lotus node" in example 3 was taken, and the water absorption thickness of the single "lotus node" was measured after splitting, and the water absorption thickness was measured to be 4.8cm, which was the same as the calculation result in step (1). The distance between lotus node is 8-13cm, and the optimal distance is 9.6cm.
Example 5
(1) The bar-shaped member similar to the lotus node is prepared according to the method of the embodiment 2, and the radius of each lotus node is 2cm, and the mass is 50g for standby; wherein the length of the strip member is 32cm;
(2) Phosphogypsum, slag and cement are mixed according to the mass ratio of 25:70:5, uniformly mixing to obtain a curing agent;
(3) Mixing the dredging sludge with a curing agent, and uniformly stirring to obtain cured sludge; wherein the water content of the dredged sludge is 125%; wherein the dosage of the curing agent is 30% of the mass of the dredged sludge;
(4) Immediately implanting the strip-shaped member obtained in the step (1) into a solidified sludge layer by virtue of a guide rod (figure 6) for adsorbing free water in solidified sludge, and drying and solidifying the strip-shaped member at room temperature for 28d; wherein the spacing of the strip members is 9.6cm;
results: the average water absorption of the strip-shaped members of the single lotus node is 63.8 percent, the water content of the dried and solidified sludge after 28 days is 38.31 percent, and the unconfined compressive strength is 32.9MPa.
Example 6
The method and procedure were the same as in example 5, using only dredging sludge with a water content of 165.3%; the water content of the dried and solidified sludge after 28 days is 39.21 percent, and the unconfined compressive strength is 30.15MPa.
Example 7
The method and steps are the same as in example 5, and only dredging sludge with water content of 198.3% is used for solidification; the water content of the solidified sludge after 28d is 40.33 percent, and the unconfined compressive strength is 28.47MPa.
Example 7
The method and the steps are the same as those in the embodiment 4, and the spacing between the strip-shaped members is changed to 13cm; the water content of the dried and solidified sludge after 28 days is 45.47 percent, and the unconfined compressive strength is 24.17MPa.
Example 8
The method and the steps are the same as those in the embodiment 4, and the spacing between the strip-shaped members is changed to 8cm; the water content of the dried and solidified sludge after 28 days is 30.15 percent, and the unconfined compressive strength is 31.76MPa.
Comparative example 1
(1) Phosphogypsum, slag and cement are mixed according to the mass ratio of 25:70:5, uniformly mixing to obtain a curing agent;
(2) Mixing the curing agent with the fluid plastic sludge, uniformly stirring, and curing for 28 days at room temperature; wherein the water content of the fluidized sludge is 125%.
The water content after drying and curing for 28 days is 78.42 percent, and the unconfined compressive strength is 5.63MPa.
Comparative example 2
(1) Cutting the non-woven fabric into a rectangle with the width of 4 pi cm and the continuous length, and continuously hot-pressing and edge-sealing along the long side to prepare a sleeve with the radius of 2cm;
(2) Phosphogypsum, slag and cement are mixed according to the mass ratio of 70:25:5, uniformly mixing to obtain phosphogypsum base powder;
(3) Filling phosphogypsum base powder into the sleeve prepared in the step (1) by using a filling segment machine, and tying a line every 4cm to prepare strip-shaped members similar to lotus root nodes, wherein the radius of each lotus root node is 2cm, and the mass of the phosphogypsum base powder is about 50g;
(4) Implanting the strip-shaped member obtained in the step (3) into the plastic-flowing sludge by using a guide rod, and curing and solidifying for 28d at room temperature; wherein the water content of the fluidized sludge is 125%.
The water content after drying and curing for 28 days is 42.68 percent, and the unconfined compressive strength is 5.32MPa.
Comparative example 3
The method and the steps are the same as those of comparative example 2, the step (3) is omitted, and the plastic sludge is directly solidified without binding the sleeve.
The moisture content 38.13% after drying and curing for 28d is 28.67MPa, and the result shows that the contact area between phosphogypsum base powder and cured sludge can be increased by packing the strip-shaped components into lotus node shapes in sections, thereby improving the unconfined compressive strength.
Comparative example 4
Because phosphogypsum base powder consists of phosphogypsum, slag and cement, wherein the phosphogypsum contains phosphorus, fluorine and other pollutants, the slag possibly contains heavy metal and other pollutants, the phosphogypsum is easy to pollute the surrounding environment in the transportation process, and the phosphogypsum is wrapped by non-woven fabrics, so that the phosphogypsum base powder not only plays a role in water diversion in water exchange, but also has the important role in fixing the phosphorus, fluorine and other pollutants. Under the wrapping of the non-woven fabrics, the phosphogypsum base powder generates a gelled product under the action of water in the sludge, and the pollutants in the phosphogypsum base powder in the non-woven fabrics are fixed on the premise of finishing water absorption.
Comparative example 5
The method and the steps are the same as those in the example 4, the non-woven fabric is replaced by cotton cloth, the water content after curing for 28 days is 38.16%, and the unconfined compressive strength is 32.2MPa; however, in the experimental process, it is found that the blocking phenomenon occurs in the water absorption process after the non-woven fabric is replaced by cotton cloth, so that the water absorption effect is poor.
Claims (9)
1. A method for drying and solidifying phosphogypsum-based powder into fluid plastic sludge is characterized by comprising the following steps: the method comprises the following steps:
(1) Preparing phosphogypsum base powder, and packaging in sections to prepare strip-shaped components;
(2) Mixing phosphogypsum, slag and cement to prepare a curing agent;
(3) Uniformly mixing a curing agent with the fluid-shaped sludge to obtain cured sludge;
(4) The strip-shaped components are implanted into the solidified sludge, and are absorbed in water for solidification.
2. The method for drying and curing the phosphogypsum-based powder and the fluid plastic sludge according to claim 1, which is characterized in that: the phosphogypsum base powder in the step (1) is prepared from phosphogypsum, slag and cement according to the mass ratio of 50-80:45-15:5, mixing.
3. The method for drying and curing the phosphogypsum-based powder and the fluid plastic sludge according to claim 1, which is characterized in that: the strip-shaped components in the step (1) are formed by packaging non-woven fabrics in sections, and each section is approximately spherical.
4. A method of drying-curing a fluid-like slurry of phosphogypsum-based powder in accordance with claim 3, wherein: the unit area mass of the non-woven fabric is 15-25g/m 2 The radius of each section is 1-3cm.
5. The method for drying and curing phosphogypsum-based powder and flowing plastic sludge, as set forth in claim 4, further comprising the steps of: the distance between each two sections is 0-13cm, and the mass of each section is 30-100g.
6. The method for drying and curing the phosphogypsum-based powder and the fluid plastic sludge according to claim 1, which is characterized in that: the mass ratio of phosphogypsum, slag and cement in the curing agent in the step (2) is 15-35:65-80:5.
7. the method for drying and curing the phosphogypsum-based powder and the fluid plastic sludge according to claim 1, which is characterized in that: the usage amount of the curing agent in the step (3) is 20-40% of the mass of the fluidized plastic sludge.
8. The method for drying and curing the phosphogypsum-based powder and the fluid plastic sludge, as set forth in claim 7, is characterized in that: the water content of the flowing plastic sludge is 120% -200%.
9. The method for drying and curing the phosphogypsum-based powder and the fluid plastic sludge according to claim 1, which is characterized in that: the spacing between the adjacent strip-shaped components in the step (4) is 8-13cm.
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