CN111302766A - Process for dewatering desilted sludge and manufacturing ceramsite by utilizing amphoteric carboxymethyl starch conditioner - Google Patents
Process for dewatering desilted sludge and manufacturing ceramsite by utilizing amphoteric carboxymethyl starch conditioner Download PDFInfo
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- CN111302766A CN111302766A CN202010093295.7A CN202010093295A CN111302766A CN 111302766 A CN111302766 A CN 111302766A CN 202010093295 A CN202010093295 A CN 202010093295A CN 111302766 A CN111302766 A CN 111302766A
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- sludge
- ceramsite
- carboxymethyl starch
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- 239000010802 sludge Substances 0.000 title claims abstract description 160
- 229920002472 Starch Polymers 0.000 title claims abstract description 89
- 235000019698 starch Nutrition 0.000 title claims abstract description 89
- 239000008107 starch Substances 0.000 title claims abstract description 89
- 125000002057 carboxymethyl group Chemical group [H]OC(=O)C([H])([H])[*] 0.000 title claims abstract description 72
- 238000000034 method Methods 0.000 title claims abstract description 48
- 230000008569 process Effects 0.000 title claims abstract description 27
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 13
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 43
- 239000005995 Aluminium silicate Substances 0.000 claims description 25
- 235000012211 aluminium silicate Nutrition 0.000 claims description 25
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 claims description 25
- 239000000292 calcium oxide Substances 0.000 claims description 25
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 claims description 25
- 239000010881 fly ash Substances 0.000 claims description 25
- NLYAJNPCOHFWQQ-UHFFFAOYSA-N kaolin Chemical compound O.O.O=[Al]O[Si](=O)O[Si](=O)O[Al]=O NLYAJNPCOHFWQQ-UHFFFAOYSA-N 0.000 claims description 25
- 238000003756 stirring Methods 0.000 claims description 17
- 238000001816 cooling Methods 0.000 claims description 14
- 238000005245 sintering Methods 0.000 claims description 9
- 239000000463 material Substances 0.000 claims description 8
- 238000002156 mixing Methods 0.000 claims description 8
- 125000002091 cationic group Chemical group 0.000 claims description 7
- 239000002245 particle Substances 0.000 claims description 6
- 229920002401 polyacrylamide Polymers 0.000 claims description 6
- 238000005469 granulation Methods 0.000 claims description 5
- 230000003179 granulation Effects 0.000 claims description 5
- 239000000919 ceramic Substances 0.000 claims description 4
- 239000003795 chemical substances by application Substances 0.000 claims description 4
- 239000008187 granular material Substances 0.000 claims description 4
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 claims description 3
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 claims description 3
- HRPVXLWXLXDGHG-UHFFFAOYSA-N Acrylamide Chemical compound NC(=O)C=C HRPVXLWXLXDGHG-UHFFFAOYSA-N 0.000 claims description 3
- 229920002125 Sokalan® Polymers 0.000 claims description 3
- 230000003750 conditioning effect Effects 0.000 claims description 3
- 238000007334 copolymerization reaction Methods 0.000 claims description 3
- 238000001914 filtration Methods 0.000 claims description 3
- 238000010438 heat treatment Methods 0.000 claims description 3
- 239000004584 polyacrylic acid Substances 0.000 claims description 3
- 238000006467 substitution reaction Methods 0.000 claims description 3
- 239000006228 supernatant Substances 0.000 claims description 2
- 230000001007 puffing effect Effects 0.000 claims 1
- 229910001385 heavy metal Inorganic materials 0.000 abstract description 54
- 230000018044 dehydration Effects 0.000 abstract description 52
- 238000006297 dehydration reaction Methods 0.000 abstract description 52
- 230000008901 benefit Effects 0.000 abstract description 6
- 229910052500 inorganic mineral Inorganic materials 0.000 abstract description 4
- 239000011707 mineral Substances 0.000 abstract description 4
- 208000005156 Dehydration Diseases 0.000 description 51
- 230000000694 effects Effects 0.000 description 34
- 238000010998 test method Methods 0.000 description 30
- 238000002386 leaching Methods 0.000 description 28
- 230000000052 comparative effect Effects 0.000 description 24
- 239000000243 solution Substances 0.000 description 17
- 238000002474 experimental method Methods 0.000 description 14
- 239000000203 mixture Substances 0.000 description 13
- 239000002994 raw material Substances 0.000 description 13
- 239000004576 sand Substances 0.000 description 12
- 239000002920 hazardous waste Substances 0.000 description 11
- 150000002500 ions Chemical class 0.000 description 11
- 239000010841 municipal wastewater Substances 0.000 description 11
- 238000004065 wastewater treatment Methods 0.000 description 11
- 238000001035 drying Methods 0.000 description 8
- 239000000047 product Substances 0.000 description 8
- 239000007787 solid Substances 0.000 description 8
- 238000010304 firing Methods 0.000 description 6
- 230000008961 swelling Effects 0.000 description 4
- 239000004566 building material Substances 0.000 description 3
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 3
- 239000000920 calcium hydroxide Substances 0.000 description 3
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 3
- 230000010355 oscillation Effects 0.000 description 3
- 229910052573 porcelain Inorganic materials 0.000 description 3
- 239000002910 solid waste Substances 0.000 description 3
- 238000007711 solidification Methods 0.000 description 3
- 230000008023 solidification Effects 0.000 description 3
- 231100000419 toxicity Toxicity 0.000 description 3
- 230000001988 toxicity Effects 0.000 description 3
- 239000002028 Biomass Substances 0.000 description 2
- 239000004927 clay Substances 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 230000002349 favourable effect Effects 0.000 description 2
- 239000010413 mother solution Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 125000003368 amide group Chemical group 0.000 description 1
- 125000000129 anionic group Chemical group 0.000 description 1
- 125000002843 carboxylic acid group Chemical group 0.000 description 1
- 238000010668 complexation reaction Methods 0.000 description 1
- 238000004332 deodorization Methods 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 238000012851 eutrophication Methods 0.000 description 1
- 239000003337 fertilizer Substances 0.000 description 1
- 239000003864 humus Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 230000002427 irreversible effect Effects 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 239000012452 mother liquor Substances 0.000 description 1
- 229920005615 natural polymer Polymers 0.000 description 1
- 239000003895 organic fertilizer Substances 0.000 description 1
- 238000000643 oven drying Methods 0.000 description 1
- 238000000053 physical method Methods 0.000 description 1
- 150000003071 polychlorinated biphenyls Chemical group 0.000 description 1
- 125000005575 polycyclic aromatic hydrocarbon group Chemical group 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
- 231100000765 toxin Toxicity 0.000 description 1
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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
- C04B33/00—Clay-wares
- C04B33/02—Preparing or treating the raw materials individually or as batches
- C04B33/13—Compounding ingredients
- C04B33/132—Waste materials; Refuse; Residues
- C04B33/1321—Waste slurries, e.g. harbour sludge, industrial muds
-
- 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
- C02F11/147—Treatment of sludge; Devices therefor by de-watering, drying or thickening with addition of chemical agents using organic 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
- C04B33/00—Clay-wares
- C04B33/02—Preparing or treating the raw materials individually or as batches
- C04B33/13—Compounding ingredients
-
- 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
- C04B33/00—Clay-wares
- C04B33/02—Preparing or treating the raw materials individually or as batches
- C04B33/13—Compounding ingredients
- C04B33/132—Waste materials; Refuse; Residues
- C04B33/135—Combustion residues, e.g. fly ash, incineration waste
- C04B33/1352—Fuel ashes, e.g. fly ash
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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
- C04B38/00—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof
- C04B38/009—Porous or hollow ceramic granular materials, e.g. microballoons
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
- C02F2103/007—Contaminated open waterways, rivers, lakes or ponds
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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
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/65—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes
- C04B2235/656—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes characterised by specific heating conditions during heat treatment
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- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/65—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes
- C04B2235/656—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes characterised by specific heating conditions during heat treatment
- C04B2235/6562—Heating rate
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- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/65—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes
- C04B2235/656—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes characterised by specific heating conditions during heat treatment
- C04B2235/6567—Treatment time
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- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P40/00—Technologies relating to the processing of minerals
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- Treatment Of Sludge (AREA)
Abstract
The invention discloses a process for dewatering desilted sludge and producing ceramsite by utilizing an amphoteric carboxymethyl starch conditioner. According to the invention, the desilting sludge is dehydrated by using the amphoteric carboxymethyl starch conditioner, and the heavy metal components are strong in fixing capacity, so that the escape of heavy metals can be greatly reduced, and the problem of heavy metal pollution of the desilting sludge can be solved; meanwhile, the content of organic components is improved, the expansion of the ceramsite is promoted, the expansion coefficient of the light aggregate reaches more than 3.0, and the expansion performance of the light aggregate is favorably improved; in addition, the amphoteric carboxymethyl starch conditioner pre-dehydration process is combined with the process for manufacturing the sintered and expanded ceramsite, so that a large amount of desilting sludge can be consumed, the consumption of mineral resources is reduced, and new economic benefits can be generated.
Description
Technical Field
The invention relates to a process for dewatering desilting sludge and manufacturing ceramsite by utilizing an amphoteric carboxymethyl starch conditioner, belonging to the technical field of desilting sludge utilization.
Background
The comprehensive treatment of rivers and lakes has become an urgent task in the field of environmental protection at present, wherein the treatment and resource utilization of sludge have become increasingly concerned problems. Taking the Taihu lake of Jiangsu province of China as an example, the Taihu lake basin is more developed in industry and agriculture, and the eutrophication situation of the water body is severe, so that the desilting sludge components are very complex. The organic fertilizer not only contains high humus substances, but also contains different types of toxic and harmful substances including heavy metals, polycyclic aromatic hydrocarbons, polychlorinated biphenyl, biotoxin and the like, and the long-time stacking can affect the surrounding environment. In addition, the water content of the desilting sludge is generally more than 90%, so that the difficulty of transportation is increased, and a large amount of generated percolate cannot be effectively and intensively treated in time, so that the potential risk of causing secondary pollution exists.
The sintered and expanded ceramsite has various excellent properties such as low density, high strength, high porosity and the like, and is widely applied to various fields such as petrochemical industry, buildings, refractory materials, soil improvement, gardens, fertilizers and the like. The desilting sludge is used as a raw material to replace clay to produce sintered and expanded ceramsite due to the special mineral composition of the desilting sludge, and becomes a new development direction of novel building materials.
However, the requirement of firing the ceramsite on the water content of the sludge is higher. Under general conditions, the water content of the biological sludge obtained by a centrifugal means is higher, generally more than 65%, and although the water content of the mixture can be reduced by adding corresponding auxiliary materials for manufacturing the ceramsite, the requirement that the water content of the raw material of the sintered and expanded ceramsite is less than 50% can not be met. In addition, the plasticity of the sludge containing high biomass presents an irreversible phenomenon, namely the biomass sludge is very fine and smooth, once the moisture on the surface is lost (including most of free water and a certain part of bound water), the sludge becomes hard and the edges are sharp gradually, and the sludge is agglomerated and loses the plasticity. The sludge will become fine sand after the secondary water injection. Therefore, reasonable dehydration of the sludge becomes a key factor for firing the ceramsite.
Disclosure of Invention
The purpose of the invention is as follows: in order to solve the technical problem, the invention provides a process for dewatering the silt and manufacturing ceramsite by using an amphoteric carboxymethyl starch conditioner.
The technical scheme is as follows: in order to achieve the purpose of the invention, the technical scheme adopted by the invention is as follows:
a process for dewatering the sludge and preparing haydite from the amphoteric carboxymethyl starch includes preparing the amphoteric carboxymethyl starch as solution, mixing it with non-dewatered fresh sludge, stirring, filtering to obtain the dewatered dry sludge, mixing it with auxiliary material, granulating and baking.
Preferably, the method comprises the following steps:
the amphoteric carboxymethyl starch conditioner is a grafted amphoteric starch conditioner obtained by graft copolymerization of cationic starch, acrylamide and acrylic acid.
Further preferably, in the grafted amphoteric starch conditioner, the substitution degree of a cationic group is 10-90%, the mass of polyacrylamide is 2-90% of that of the grafted amphoteric starch conditioner, and the mass of polyacrylic acid is 10-75% of that of the grafted amphoteric starch conditioner.
The initial water content of the undehydrated fresh sludge is 92-97%.
The amphoteric carboxymethyl starch conditioner is prepared into a solution by the following method: the conditioner was added to pure water at room temperature and stirred well until the solution was clear and transparent.
The amphoteric carboxymethyl starch conditioner and the non-dehydrated fresh sludge are prepared from 4/1001-10/1001 parts by mass: 1000 parts.
The method for mixing and stirring the sludge with the undried fresh sludge comprises the following steps: placing the fresh sludge which is not dehydrated under the stirring condition, adding the conditioner solution while stirring, stirring for a certain time, then reducing the rotating speed, continuing stirring for a certain time, and standing the system after stirring.
The ceramic making auxiliary materials comprise fly ash, calcium oxide and kaolin.
Further preferably, the mass parts of the fly ash, the calcium oxide, the kaolin and the dry sludge are as follows:
dry base sludge: 140 parts of (B); fly ash: 6-10 parts; kaolin: 6-10 parts; calcium oxide: 3-5 parts;
the diameter of the particles prepared by granulation is 3-5mm, and the particles are dried for 12h at the temperature of 105-.
The method of said sintering is as follows:
taking the particles prepared by granulation, firstly heating to the temperature of 300-450 ℃ by a program for preheating for 40-60min, and then carrying out sintering expansion at the temperature of 800-1200 ℃ for 15-30 min; cooling for 30-45min at the temperature of 200-450 ℃ after sintering and expanding, and finally cooling to room temperature to obtain sintered ceramsite
The amphoteric carboxymethyl starch used in the invention is a novel environment-friendly natural polymer conditioner with amphoteric characteristics, which is rich in anionic and cationic groups on molecular chains, and has good functions of dehydration (including most of free water and a certain part of bound water), metal ion complexation, bacteriostasis, deodorization and the like. The physicochemical properties of the sludge, including the water content, the heavy metal solidification rate and the organic component content of the sludge, can be greatly improved, the organic component content of the sludge can be further improved by the sludge, the pore-forming agent can be used in the firing and expansion process of the ceramsite, and the porosity of the firing and expansion ceramsite can be effectively improved. In addition, the amphoteric carboxymethyl starch has the characteristic of high efficiency, the dosage is as low as 0.1-10mg/g of dry mud, the amphoteric carboxymethyl starch shows good salt resistance in water-mud mixed systems with different charges, and the pH can be applied within 1-12. The starch source is wide and the price is low, so the graft amphoteric starch conditioner has higher cost performance and can be widely applied in actual production.
Therefore, the innovation of the invention is as follows: (1) the amphoteric carboxymethyl starch conditioner is used for carrying out pre-dehydration treatment on the Taihu lake silt with high water content, the amphoteric starch has good solubility and is easy to fully disperse in the silt in the conditioning process, and after the Taihu lake silt is dehydrated by the amphoteric carboxymethyl starch conditioner, the water content of the silt is reduced to 50.1% under the condition of the optimal addition amount of the conditioner. (ii) a (2) The carboxylic acid group and the amide group of the used amphoteric carboxymethyl starch can effectively solidify heavy metal elements contained in the desilting sludge and prevent the heavy metal from escaping to cause secondary pollution; (3) the used amphoteric carboxymethyl starch can further improve the content of organic components in the silt, and can be used as a pore-forming agent in the firing and expansion process of the ceramsite, so that the porosity of the firing and expansion ceramsite is improved; (4) the used amphoteric carboxymethyl starch conditioner contains rich amphoteric groups, can efficiently combine various auxiliary materials added in the ceramsite burning expansion process, and promotes the full mixing of materials; (5) the dewatered desilting sludge is directly used for burning expanded ceramsite, so that the desilting sludge can be recycled, the consumption of clay and other mineral resources can be reduced, and the problem that a large amount of building material raw materials cannot be regenerated and are short in source is solved.
Has the advantages that: compared with the prior art, the invention has the following advantages:
(1) the amphoteric carboxymethyl starch conditioner has good dehydration performance, and the dewatered desilted sludge is mixed with the fly ash, the kaolin and the calcium oxide, so that the technical requirement for manufacturing the sintered ceramsite can be met; good economic benefit and environmental benefit;
(2) the amphoteric carboxymethyl starch conditioner has strong fixing capacity on heavy metal components, can greatly reduce the escape of heavy metals, and can solve the problem of heavy metal pollution of silt;
(3) the amphoteric carboxymethyl starch improves the content of organic components, promotes the expansion of the ceramsite, ensures that the expansion coefficient of the light aggregate reaches more than 3.0, is favorable for improving the expansion performance of the light aggregate, and is favorable for improving the performances of heat preservation, energy conservation, sound insulation, noise reduction and the like of the generated building material;
(4) the amphoteric carboxymethyl starch conditioner pre-dehydration process is combined with the process for manufacturing the sintered ceramic particles, so that a large amount of desilting sludge can be consumed, the consumption of mineral resources can be reduced, new economic benefits can be generated, and two purposes are achieved.
Drawings
FIG. 1 is a graph showing the relationship between the amount of a conditioner added and the water content;
FIG. 2 is a graph showing the relationship between different raw material compositions, the sintering-expansion temperature, the sintering-expansion time and the ceramic particle barrel pressure strength;
FIG. 3 is the relationship between different raw material compositions, the sintering-expansion temperature, the sintering-expansion time and the expansion coefficient of the ceramsite.
Detailed Description
The technical solution of the present invention is further described in detail by the following specific examples.
In the following examples, the Taihu lake dredging sludge is used as the non-dehydrated fresh sludge, the initial water content is 92-97%, and the specific process is as follows:
(1) carrying out dehydration pretreatment on the silt removed from the Taihu lake:
(a) preparing a conditioner mother solution: 1 part of amphoteric carboxymethyl starch conditioner; 1000 parts of pure water. The conditioner was added to pure water at room temperature and stirred well until the solution was clear and transparent.
The amphoteric carboxymethyl starch conditioner is a grafted amphoteric starch conditioner obtained by graft copolymerization of cationic starch, acrylamide and acrylic acid. Wherein, the substitution degree of the cationic group is 10 to 90 percent, the mass of the polyacrylamide is 2 to 90 percent of the mass of the graft amphoteric starch conditioner, and the mass of the polyacrylic acid is 10 to 75 percent of the mass of the graft amphoteric starch conditioner.
(b) Taking 4-10 parts of the conditioner mother liquor and 1000 parts of non-dehydrated fresh sludge; placing fresh sludge under the condition that the rotating speed is 200rpm, adding a conditioner mother solution while stirring for 10min, and then continuously stirring for 20min under the condition that the rotating speed is adjusted to 50 rpm; and standing the system for 60min after stirring is finished, and filtering out supernatant to obtain dehydrated dry-based sludge.
(2) Mixing materials: uniformly mixing and stirring the fly ash, the calcium oxide, the kaolin and the dry sludge, wherein the specific feeding conditions are as follows:
dry base sludge: 140 parts of (B);
fly ash: 6-10 parts;
kaolin: 6-10 parts;
calcium oxide: 3-5 parts;
(3) and (3) granulation: directly granulating the above mixture, granulating into balls (diameter of about 3-5mm), and oven drying at 105-120 deg.C for 12 hr.
(4) And (3) burning and swelling: and (3) placing the dried ceramsite spheres in a furnace, and heating at the speed of 8 ℃/min, wherein the preheating temperature is 300-. The burning and swelling temperature of the burning and swelling ceramsite containing the silt removed from the Taihu lake is 800-1200 ℃, and the burning and swelling time is 15-30 min. Cooling for 30-45min at the temperature of 200-450 ℃ after sintering and expanding, and then cooling to room temperature to obtain the fired ceramsite.
Example 1:
the dosage of the amphoteric carboxymethyl starch conditioner is as follows: 4 portions of
Dredging sludge: 1000 portions
The raw materials comprise:
140 portions of dry-base sludge
6 portions of fly ash
6 parts of kaolin
3 portions of calcium oxide
The amphoteric carboxymethyl starch conditioner and the desilting sludge are added in proportion for pre-dehydration treatment. The treated sludge solid sample is uniformly mixed with three components of fly ash, kaolin and calcium oxide, and the mixture is directly granulated. Drying and preheating the prepared ceramsite, and burning and expanding the ceramsite for 15min at the temperature of 800 ℃. Cooling to room temperature to obtain a ceramsite finished product.
The water content of the sludge before and after dehydration is measured by GB/T24600 sludge for brickmaking in sludge disposal of municipal wastewater treatment plants. As can be seen from FIG. 1, the water content of the sludge after dehydration was 59.8%. The amphoteric carboxymethyl starch conditioner has good dehydration effect. The cylinder pressure strength of the ceramsite is measured by a method specified in national standard GB/T17431-1998 light aggregate and test method thereof, wherein the parallel test is 5 groups, and the results of measuring the cylinder pressure strength of the ceramsite are shown in an example 1 in figure 2, and the average cylinder pressure strength of the 5 groups is 2.79 MPa. The cylinder pressure strength of the manufactured ceramsite meets the national standard on the cylinder pressure strength requirement of the ceramsite of the common sand sludge. According to the heavy metal concentration in the leaching solution of the hazardous waste, the measured heavy metal leaching concentration under the condition is Zn: 0.08 mg/L; cu: 0.01 mg/L; cr: 0.03 mg/L; pb: 0 mg/L. Is far less than the discharge standard of the national standard about the heavy metal ions, and has good heavy metal curing effect. GB-T17431.1-2010 part 2 of lightweight aggregate and test method thereof is adopted: test method for lightweight aggregates the expansion coefficient of the samples was measured using five sets of parallel experiments, and the results are shown in example 1 in fig. 3. The 5 results are averaged to obtain a ceramsite having an expansion coefficient of 3.5. The expansion effect of the ceramsite is good (more than or equal to 3.0).
Example 2:
the dosage of the amphoteric carboxymethyl starch conditioner is as follows: 6 portions of
Dredging sludge: 1000 portions
The raw materials comprise:
140 portions of dry-base sludge
8 portions of fly ash
8 portions of kaolin
4 portions of calcium oxide
The amphoteric carboxymethyl starch conditioner and the desilting sludge are added in proportion for pre-dehydration treatment. The treated sludge solid sample is uniformly mixed with three components of fly ash, kaolin and calcium oxide, and the mixture is directly granulated. Drying and preheating the prepared ceramsite, and sintering and expanding the ceramsite for 20min at 900 ℃. Cooling to room temperature to obtain a ceramsite finished product.
The water content of the sludge before and after dehydration is measured by GB/T24600 sludge for brickmaking in sludge disposal of municipal wastewater treatment plants. As can be seen from FIG. 1, the water content of the sludge after dehydration was 56.3%. The amphoteric carboxymethyl starch conditioner has good dehydration effect. The cylinder pressure strength of the ceramsite is measured by a method specified in national standard GB/T17431-1998 light aggregate and test method thereof, wherein the parallel test is 5 groups, and the results of measuring the cylinder pressure strength of the ceramsite are shown in an example 2 in a figure 2, and the average cylinder pressure strength of the 5 groups is 2.15 MPa. The cylinder pressure strength of the manufactured ceramsite meets the national standard on the cylinder pressure strength requirement of the ceramsite of the common sand sludge. According to the heavy metal concentration in the leaching solution of the hazardous waste, the measured heavy metal leaching concentration under the condition is Zn: 0.06 mg/L; cu: 0.04 mg/L; cr: 0.01 mg/L; pb: 0.01 mg/L. Is far less than the discharge standard of the national standard about the heavy metal ions, and has good heavy metal curing effect. GB-T17431.1-2010 part 2 of lightweight aggregate and test method thereof is adopted: test method for lightweight aggregate the expansion coefficient of the samples was measured using five sets of parallel experiments, and the results are shown in example 2 of fig. 3. The 5 results are averaged to obtain a ceramsite having an expansion coefficient of 3.3. The expansion effect of the ceramsite is good (more than or equal to 3.0).
Example 3:
the dosage of the amphoteric carboxymethyl starch conditioner is as follows: 8 portions of
Dredging sludge: 1000 portions
The raw materials comprise:
140 portions of dry-base sludge
10 portions of fly ash
10 portions of kaolin
5 portions of calcium oxide
The amphoteric carboxymethyl starch conditioner and the desilting sludge are added in proportion for pre-dehydration treatment. The treated sludge solid sample is uniformly mixed with three components of fly ash, kaolin and calcium oxide, and the mixture is directly granulated. Drying and preheating the prepared ceramsite, and sintering and expanding the ceramsite for 20min at 900 ℃. Cooling to room temperature to obtain a ceramsite finished product.
The water content of the sludge before and after dehydration is measured by GB/T24600 sludge for brickmaking in sludge disposal of municipal wastewater treatment plants. As can be seen from FIG. 1, the water content of the sludge after dehydration was 50.1%. The amphoteric carboxymethyl starch conditioner has good dehydration effect. The cylinder pressure strength of the ceramsite is measured by a method specified in national standard GB/T17431-1998 light aggregate and test method thereof, wherein the parallel test is 5 groups, and the results of measuring the cylinder pressure strength of the ceramsite are shown in an example 3 in a figure 2, and the average cylinder pressure strength of the 5 groups is 2.65 MPa. The cylinder pressure strength of the manufactured ceramsite meets the national standard on the cylinder pressure strength requirement of the ceramsite of the common sand sludge. According to the heavy metal concentration in the leaching solution of the hazardous waste, the measured heavy metal leaching concentration under the condition is Zn: 0.09 mg/L; cu: 0.02 mg/L; cr: 0.01 mg/L; pb: 0.02 mg/L. Is far less than the discharge standard of the national standard about the heavy metal ions, and has good heavy metal curing effect. GB-T17431.1-2010 part 2 of lightweight aggregate and test method thereof is adopted: test method for lightweight aggregate the expansion coefficient of the samples was measured using five sets of parallel experiments, and the results are shown in example 3 in fig. 3. The 5 results are averaged to obtain a ceramsite having an expansion coefficient of 3.8. The expansion effect of the ceramsite is good (more than or equal to 3.0).
Example 4:
the dosage of the amphoteric carboxymethyl starch conditioner is as follows: 10 portions of
Dredging sludge: 1000 portions
The raw materials comprise:
140 portions of dry-base sludge
6 portions of fly ash
6 parts of kaolin
3 portions of calcium oxide
The amphoteric carboxymethyl starch conditioner and the desilting sludge are added in proportion for pre-dehydration treatment. The treated sludge solid sample is uniformly mixed with three components of fly ash, kaolin and calcium oxide, and the mixture is directly granulated. Drying and preheating the prepared ceramsite, and burning and expanding the ceramsite for 25min at the temperature of 1000 ℃. Cooling to room temperature to obtain a ceramsite finished product.
The water content of the sludge before and after dehydration is measured by GB/T24600 sludge for brickmaking in sludge disposal of municipal wastewater treatment plants. As can be seen from FIG. 1, the water content of the sludge after dehydration was 57.1%. The amphoteric carboxymethyl starch conditioner has good dehydration effect. The cylinder pressure strength of the ceramsite is measured by a method specified in national standard GB/T17431-1998 light aggregate and test method thereof, wherein the parallel test is 5 groups, and the results of measuring the cylinder pressure strength of the ceramsite are shown in an example 4 in figure 2, and the average cylinder pressure strength of the 5 groups is 2.55 MPa. The cylinder pressure strength of the manufactured ceramsite meets the national standard on the cylinder pressure strength requirement of the ceramsite of the common sand sludge. According to the heavy metal concentration in the leaching solution of the hazardous waste, the measured heavy metal leaching concentration under the condition is Zn: 0.06 mg/L; cu: 0.01 mg/L; cr: 0.03 mg/L; pb: 0.02 mg/L. Is far less than the discharge standard of the national standard about the heavy metal ions, and has good heavy metal curing effect. GB-T17431.1-2010 part 2 of lightweight aggregate and test method thereof is adopted: test method for lightweight aggregate the expansion coefficient of the samples was measured using five sets of parallel experiments, and the results are shown in example 4 of fig. 3. The 5 results are averaged to obtain a ceramsite having an expansion coefficient of 3.6. The expansion effect of the ceramsite is good (more than or equal to 3.0).
Example 5:
the dosage of the amphoteric carboxymethyl starch conditioner is as follows: 8 portions of
Dredging sludge: 1000 portions
The raw materials comprise:
140 portions of dry-base sludge
8 portions of fly ash
8 portions of kaolin
4 portions of calcium oxide
The amphoteric carboxymethyl starch conditioner and the desilting sludge are added in proportion for pre-dehydration treatment. The treated sludge solid sample is uniformly mixed with three components of fly ash, kaolin and calcium oxide, and the mixture is directly granulated. Drying and preheating the prepared ceramsite, and burning and expanding the ceramsite for 25min at 1100 ℃. Cooling to room temperature to obtain a ceramsite finished product.
The water content of the sludge before and after dehydration is measured by GB/T24600 sludge for brickmaking in sludge disposal of municipal wastewater treatment plants. As can be seen from FIG. 1, the water content of the sludge after dehydration was 50.1%. The amphoteric carboxymethyl starch conditioner has good dehydration effect. The cylinder pressure strength of the ceramsite is measured by a method specified in national standard GB/T17431-1998 light aggregate and test method thereof, and the cylinder pressure strength of the ceramsite is 5 groups, and the average cylinder pressure strength of the 5 groups is 3.55MPa in example 5 in figure 2. The cylinder pressure strength of the manufactured ceramsite meets the national standard on the cylinder pressure strength requirement of the ceramsite of the common sand sludge. According to the heavy metal concentration in the leaching solution of the hazardous waste, the measured heavy metal leaching concentration under the condition is Zn: 0.06 mg/L; cu: 0.01 mg/L; cr: 0.02 mg/L; pb: 0.01 mg/L. Is far less than the discharge standard of the national standard about the heavy metal ions, and has good heavy metal curing effect. GB-T17431.1-2010 part 2 of lightweight aggregate and test method thereof is adopted: test method for lightweight aggregates the expansion coefficient of the samples was measured using five sets of parallel experiments, and the results are shown in example 5 in fig. 3. The 5 results are averaged to obtain a ceramsite having an expansion coefficient of 3.2. The expansion effect of the ceramsite is good (more than or equal to 3.0).
Example 6:
the dosage of the amphoteric carboxymethyl starch conditioner is as follows: 8 portions of
Dredging sludge: 1000 portions
The raw materials comprise:
140 portions of dry-base sludge
10 portions of fly ash
10 portions of kaolin
5 portions of calcium oxide
The amphoteric carboxymethyl starch conditioner and the desilting sludge are added in proportion for pre-dehydration treatment. The treated sludge solid sample is uniformly mixed with three components of fly ash, kaolin and calcium oxide, and the mixture is directly granulated. Drying and preheating the prepared ceramsite, and sintering and expanding for 30min at 1200 ℃. Cooling to room temperature to obtain a ceramsite finished product.
The water content of the sludge before and after dehydration is measured by GB/T24600 sludge for brickmaking in sludge disposal of municipal wastewater treatment plants. As can be seen from FIG. 1, the water content of the sludge after dehydration was 50.1%. The amphoteric carboxymethyl starch conditioner has good dehydration effect. The cylinder pressure strength of the ceramsite is measured by a method specified in national standard GB/T17431-1998 light aggregate and test method thereof, and the cylinder pressure strength of the ceramsite is 5 groups, and the average cylinder pressure strength of the 5 groups is 4.20MPa in example 6 in FIG. 2. The cylinder pressure strength of the manufactured ceramsite meets the national standard on the cylinder pressure strength requirement of the ceramsite of the common sand sludge. According to the heavy metal concentration in the leaching solution of the hazardous waste, the measured heavy metal leaching concentration under the condition is Zn: 0.05 mg/L; cu: 0 mg/L; cr: 0.03 mg/L; pb: 0.01 mg/L. Is far less than the discharge standard of the national standard about the heavy metal ions, and has good heavy metal curing effect. GB-T17431.1-2010 part 2 of lightweight aggregate and test method thereof is adopted: test method for lightweight aggregate the expansion coefficient of the samples was measured using five sets of parallel experiments, and the results are shown in example 6 in fig. 3. The 5 results are averaged to obtain a ceramsite having an expansion coefficient of 3.8. The expansion effect of the ceramsite is good (more than or equal to 3.0).
Example 7:
the dosage of the amphoteric carboxymethyl starch conditioner is as follows: 6 portions of
Dredging sludge: 1000 portions
The raw materials comprise:
140 portions of dry-base sludge
6 portions of fly ash
6 parts of kaolin
3 portions of calcium oxide
The amphoteric carboxymethyl starch conditioner and the desilting sludge are added in proportion for pre-dehydration treatment. The treated sludge solid sample is uniformly mixed with three components of fly ash, kaolin and calcium oxide, and the mixture is directly granulated. Drying and preheating the prepared ceramsite, and burning and expanding the ceramsite for 30min at 900 ℃. Cooling to room temperature to obtain a ceramsite finished product.
The water content of the sludge before and after dehydration is measured by GB/T24600 sludge for brickmaking in sludge disposal of municipal wastewater treatment plants. As can be seen from FIG. 1, the water content of the sludge after dehydration was 56.3%. The amphoteric carboxymethyl starch conditioner has good dehydration effect. The cylinder pressure strength of the ceramsite is measured by a method specified in national standard GB/T17431-1998 light aggregate and test method thereof, wherein the parallel test is 5 groups, and the results of measuring the cylinder pressure strength of the ceramsite are shown in example 7 in figure 2, and the average cylinder pressure strength of the 5 groups is 2.60 MPa. The cylinder pressure strength of the manufactured ceramsite meets the national standard on the cylinder pressure strength requirement of the ceramsite of the common sand sludge. According to the heavy metal concentration in the leaching solution of the hazardous waste, the measured heavy metal leaching concentration under the condition is Zn: 0.08 mg/L; cu: 0.03 mg/L; cr: 0.01 mg/L; pb: 0.02 mg/L. Is far less than the discharge standard of the national standard about the heavy metal ions, and has good heavy metal curing effect. GB-T17431.1-2010 part 2 of lightweight aggregate and test method thereof is adopted: test method for lightweight aggregates the expansion coefficient of the samples was measured using five sets of parallel experiments, and the results are shown in example 7 in fig. 3. The 5 results are averaged to obtain a ceramsite having an expansion coefficient of 3.9. The expansion effect of the ceramsite is good (more than or equal to 3.0).
Example 8:
the dosage of the amphoteric carboxymethyl starch conditioner is as follows: 10 portions of
Dredging sludge: 1000 portions
The raw materials comprise:
140 portions of dry-base sludge
8 portions of fly ash
8 portions of kaolin
4 portions of calcium oxide
The amphoteric carboxymethyl starch conditioner and the desilting sludge are added in proportion for pre-dehydration treatment. The treated sludge solid sample is uniformly mixed with three components of fly ash, kaolin and calcium oxide, and the mixture is directly granulated. Drying and preheating the prepared ceramsite, and burning and expanding the ceramsite for 30min at the temperature of 1000 ℃. Cooling to room temperature to obtain a ceramsite finished product.
The water content of the sludge before and after dehydration is measured by GB/T24600 sludge for brickmaking in sludge disposal of municipal wastewater treatment plants. As can be seen from FIG. 1, the water content of the sludge after dehydration was 57.1%. The amphoteric carboxymethyl starch conditioner has good dehydration effect. The cylinder pressure strength of the ceramsite is measured by a method specified in national standard GB/T17431-1998 light aggregate and test method thereof, wherein the parallel test is 5 groups, and the results of measuring the cylinder pressure strength of the ceramsite are shown in example 8 in figure 2, and the average cylinder pressure strength of 5 groups is 2.26 MPa. The cylinder pressure strength of the manufactured ceramsite meets the national standard on the cylinder pressure strength requirement of the ceramsite of the common sand sludge. According to the heavy metal concentration in the leaching solution of the hazardous waste, the measured heavy metal leaching concentration under the condition is Zn: 0.05 mg/L; cu: 0.01 mg/L; cr: 0.02 mg/L; pb: 0.01 mg/L. Is far less than the discharge standard of the national standard about the heavy metal ions, and has good heavy metal curing effect. GB-T17431.1-2010 part 2 of lightweight aggregate and test method thereof is adopted: test method for lightweight aggregate the expansion coefficient of the samples was measured using five sets of parallel experiments, and the results are shown in example 8 in fig. 3. The 5 results are averaged to obtain a ceramsite having an expansion coefficient of 4.0. The expansion effect of the ceramsite is good (more than or equal to 3.0).
Comparative examples 1 to 3:
the amount of the amphoteric carboxymethyl starch conditioner used in the above examples 1, 6 and 8 was changed to 0 part. The early dehydration pretreatment process is changed into: firstly, a centrifuge is used for dehydration under the condition of 3000-plus 5000rpm, and the dehydrated sludge is secondarily dehydrated by a plate-and-frame filter press, so that the obtained sludge is dry-base sludge. The amounts of the other components added and the experimental conditions were kept the same as in the corresponding examples.
The water content of the sludge before and after dehydration is measured by GB/T24600 sludge for brickmaking in sludge disposal of municipal wastewater treatment plants. The water contents of the sludge after the dehydration of comparative examples 1 to 3 were 63.8%, 64.2%, and 64.8%, respectively. Compared with the dehydration effect of the amphoteric carboxymethyl starch conditioner, the dehydration effect of the simple physical method is poorer; the method specified by national standard GB/T17431-1998 light aggregate and test method thereof is adopted, the parallel test is 5 groups, the average cylinder pressure strength of the porcelain granules in comparative examples 1-3 is respectively 1.89MPa, 2.21MPa and 1.98MPa, and the cylinder pressure strength part of the manufactured porcelain granules does not meet the national standard for the cylinder pressure strength requirement of the porcelain granules of the ordinary sand sludge; according to the concentration of heavy metals in the leaching solution of the hazardous waste, the leaching concentrations of the heavy metals in the ceramsite in comparative examples 1 to 3 are respectively determined as in comparative example 1 by adopting the national standard GB5085.2-1997 solid waste leaching toxicity leaching method-horizontal oscillation method: zn: 0.16 mg/L; cu: 0.10 mg/L; cr: 0.13 mg/L; pb: 0.08mg/L, comparative example 2: zn: 0.15 mg/L; cu: 0.09 mg/L; cr: 0.11 mg/L; pb: 0.07mg/L, comparative example 3: zn: 0.16 mg/L; cu: 0.08 mg/L; cr: 0.08 mg/L; pb: 0.06 mg/L; the concentration of partial heavy metal components is higher than the upper limit of the national standard on the discharge standard of the heavy metal ions, and compared with the amphoteric carboxymethyl starch conditioner, the heavy metal solidification effect of the sludge without the amphoteric carboxymethyl starch conditioner is poorer; GB-T17431.1-2010 part 2 of lightweight aggregate and test method thereof is adopted: the expansion coefficient of the sample is measured by the experimental method for light aggregate, five groups of parallel experiments are adopted, and the average value is taken. The expansion coefficients of the ceramsite prepared in comparative examples 1-3 are 1.8, 1.6 and 1.9 respectively, the expansion coefficient of the ceramsite is less than 3.0, and the expansion effect is poor.
Comparative examples 4 to 6:
the amphoteric carboxymethyl starch conditioner used in the above examples 1, 6 and 8 is changed into common commercial inorganic dehydration conditioner calcium hydroxide, and the rest of the operation conditions are not changed, and the addition amount of the obtained dry-based sludge and other components and other experimental conditions are consistent with the corresponding examples.
The water content of the sludge before and after dehydration is measured by GB/T24600 sludge for brickmaking in sludge disposal of municipal wastewater treatment plants. The water contents of the sludge after the dehydration of comparative examples 4 to 6 were 60.7%, 61.2%, and 59.8%, respectively. Compared with an amphoteric carboxymethyl starch conditioner, the sludge dewatering effect of the calcium hydroxide used as a common commercial inorganic dewatering conditioner is better; the method specified by national standard GB/T17431-1998 lightweight aggregate and test method thereof is adopted, the parallel test is 5 groups, the average cylinder pressure strength of the ceramsite in comparative examples 4-6 is respectively 2.01MPa, 2.19MPa and 2.13MPa, the cylinder pressure strength of the manufactured ceramsite is barely in line with the national standard on the cylinder pressure strength requirement of the ceramsite of ordinary sand sludge, and the mechanical property of the ceramsite is unstable; according to the concentration of heavy metals in the leaching solution of the hazardous waste, the leaching concentrations of the ceramsite in comparative examples 4 to 6 are respectively determined as the following comparative example 4 by adopting the national standard GB5085.2-1997 solid waste leaching toxicity leaching method-horizontal oscillation method: zn: 0.14 mg/L; cu: 0.09 mg/L; cr: 0.13 mg/L; pb: 0.08mg/L, comparative example 5: zn: 0.12 mg/L; cu: 0.08 mg/L; cr: 0.14 mg/L; pb: 0.07mg/L, comparative example 6: zn: 0.15 mg/L; cu: 0.08 mg/L; cr: 0.15 mg/L; pb: 0.06 mg/L; part of heavy metal components do not meet the upper limit of the discharge standard of the above heavy metal ions of the national standard, and compared with the amphoteric carboxymethyl starch conditioner, the sludge is pretreated by using the common commercial inorganic dehydration conditioner calcium hydroxide, so that the heavy metal curing effect of the sludge is poorer; GB-T17431.1-2010 part 2 of lightweight aggregate and test method thereof is adopted: the expansion coefficient of the sample is measured by the experimental method for light aggregate, five groups of parallel experiments are adopted, and the average value is taken. The expansion coefficients of the ceramsite prepared in comparative examples 4-6 are 1.7, 2.1 and 2.3 respectively. The expansion coefficient of the ceramsite is less than 3.0, and the expansion effect is poor.
Comparative examples 7 to 9:
the amphoteric carboxymethyl starch conditioner used in the above examples 1, 6 and 8 was changed to polyacrylamide which is a common commercial organic dehydration conditioner, and the rest of the operation conditions were not changed, and the addition amounts of the obtained dry-based sludge and other components and other experimental conditions were consistent with those of the corresponding examples.
The water content of the sludge before and after dehydration is measured by GB/T24600 sludge for brickmaking in sludge disposal of municipal wastewater treatment plants. The water contents of the sludge after the dewatering of comparative examples 7 to 9 were 61.4%, 59.2%, and 58.8%, respectively. Compared with an amphoteric carboxymethyl starch conditioner, the sludge dewatering effect of the polyacrylamide serving as a common commercial organic dewatering conditioner is better; the method specified by national standard GB/T17431-1998 light aggregate and test method thereof is adopted, the parallel test is 5 groups, the average cylinder pressure strength of the ceramsite in comparative examples 7-9 is respectively 2.11MPa, 2.45MPa and 2.23MPa, the cylinder pressure strength of the manufactured ceramsite meets the national standard on the cylinder pressure strength requirement of the ceramsite of the ordinary sand sludge, and the mechanical property of the ceramsite is poorer than that of the ceramsite manufactured by pretreating the sludge by using the amphoteric carboxymethyl starch conditioner; according to the concentration of heavy metals in the leaching solution of the hazardous waste, the leaching concentrations of the ceramsite in comparative examples 7 to 9 are respectively determined as in comparative example 7 by adopting the national standard GB5085.2-1997 solid waste leaching toxicity leaching method-horizontal oscillation method: zn: 0.10 mg/L; cu: 0.07 mg/L; cr: 0.08 mg/L; pb: 0.05mg/L, comparative example 8: zn: 0.09 mg/L; cu: 0.05 mg/L; cr: 0.07 mg/L; pb: 0.05mg/L, comparative example 9: zn: 0.10 mg/L; cu: 0.06 mg/L; cr: 0.06 mg/L; pb: 0.06 mg/L; the method meets the upper limit of the national standard on the discharge standard of the heavy metal ions, but compared with the amphoteric carboxymethyl starch conditioner, the sludge is pretreated by using polyacrylamide which is a common commercial organic dehydration conditioner, and the heavy metal solidification effect of the sludge is poorer. GB-T17431.1-2010 part 2 of lightweight aggregate and test method thereof is adopted: the expansion coefficient of the sample is measured by the experimental method for light aggregate, five groups of parallel experiments are adopted, and the average value is taken. The expansion coefficients of the ceramsite prepared in comparative examples 7-9 are 2.3, 2.6 and 2.8 respectively. The expansion coefficient of the ceramsite is less than 3.0, and the expansion effect is poor.
Claims (11)
1. A process for dewatering sludge and making haydite by using amphoteric carboxymethyl starch as conditioning agent includes such steps as preparing the amphoteric carboxymethyl starch as conditioning agent into solution, mixing it with non-dewatered fresh sludge, stirring, filtering to obtain supernatant, mixing it with auxiliary material for preparing pottery, granulating and baking.
2. The process for dewatering the silt and manufacturing the ceramsite according to claim 1, wherein the amphoteric carboxymethyl starch conditioner is a graft amphoteric starch conditioner obtained by graft copolymerization of cationic starch, acrylamide and acrylic acid.
3. The process for dewatering the silt and manufacturing the ceramsite by using the amphoteric carboxymethyl starch conditioner according to claim 2, wherein in the grafted amphoteric starch conditioner, the substitution degree of cationic groups is 10% -90%, the mass of polyacrylamide is 2% -90% of the mass of the grafted amphoteric starch conditioner, and the mass of polyacrylic acid is 10% -75% of the mass of the grafted amphoteric starch conditioner.
4. The process for dewatering sludge and making ceramsite according to claim 1, wherein said non-dewatered fresh sludge has an initial moisture content of 92% -97%.
5. The process for dewatering sludge and producing ceramsite according to claim 1, wherein said amphoteric carboxymethyl starch conditioner is prepared as a solution by the following steps: the conditioner was added to pure water at room temperature and stirred well until the solution was clear and transparent.
6. The process for dewatering sludge and producing ceramsite by using amphoteric carboxymethyl starch conditioner according to claim 1, wherein the mass ratio of amphoteric carboxymethyl starch conditioner to undried fresh sludge is 4/1001-10/1001: 1000 parts.
7. The process for dewatering sludge and producing ceramsite by using amphoteric carboxymethyl starch conditioner according to claim 1, wherein said sludge is mixed with fresh sludge without dewatering by the following method: placing the fresh sludge which is not dehydrated under the stirring condition, adding the conditioner solution while stirring, stirring for a certain time, then reducing the rotating speed, continuing stirring for a certain time, and standing the system after stirring.
8. The process for dewatering the silt and manufacturing the ceramsite by using the amphoteric carboxymethyl starch conditioner according to claim 1, wherein the ceramic auxiliary materials comprise fly ash, calcium oxide and kaolin.
9. The process for dewatering the silt and manufacturing the ceramsite according to claim 8, wherein the fly ash, the calcium oxide, the kaolin and the dry silt are mixed in the following proportions by weight:
dry base sludge: 140 parts of (B); fly ash: 6-10 parts; kaolin: 6-10 parts; calcium oxide: 3-5 parts.
10. The process for dewatering silt and producing ceramsite by using the amphoteric carboxymethyl starch conditioner as claimed in claim 1, wherein the granules obtained by granulation have a diameter of 3-5mm, and are dried at 120 ℃ for 12 h.
11. The process for dewatering sludge and producing ceramsite by using amphoteric carboxymethyl starch conditioner according to claim 1, wherein said method for puffing comprises:
taking the particles prepared by granulation, firstly heating to the temperature of 300-450 ℃ by a program for preheating for 40-60min, and then carrying out sintering expansion at the temperature of 800-1200 ℃ for 15-30 min; cooling for 30-45min at the temperature of 200-450 ℃ after the sintering and expansion, and finally cooling to room temperature to obtain the sintered ceramsite.
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