CN111420966A - Method for treating heavy metal in stable fly ash of N-30 alkaline silica sol - Google Patents
Method for treating heavy metal in stable fly ash of N-30 alkaline silica sol Download PDFInfo
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- CN111420966A CN111420966A CN202010216102.2A CN202010216102A CN111420966A CN 111420966 A CN111420966 A CN 111420966A CN 202010216102 A CN202010216102 A CN 202010216102A CN 111420966 A CN111420966 A CN 111420966A
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- fly ash
- silica sol
- alkaline silica
- reaction kettle
- temperature
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- 239000010881 fly ash Substances 0.000 title claims abstract description 50
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 title claims abstract description 42
- 229910001385 heavy metal Inorganic materials 0.000 title claims abstract description 22
- 238000000034 method Methods 0.000 title claims abstract description 16
- 241001494115 Stomoxys calcitrans Species 0.000 title abstract description 6
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims abstract description 30
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 22
- 238000003756 stirring Methods 0.000 claims abstract description 16
- 239000008367 deionised water Substances 0.000 claims abstract description 12
- 229910021641 deionized water Inorganic materials 0.000 claims abstract description 12
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 10
- 239000011863 silicon-based powder Substances 0.000 claims abstract description 10
- 239000000203 mixture Substances 0.000 claims abstract description 8
- 239000002245 particle Substances 0.000 claims abstract description 6
- 238000005303 weighing Methods 0.000 claims abstract description 4
- 239000000463 material Substances 0.000 claims abstract description 3
- 238000010438 heat treatment Methods 0.000 claims description 12
- 238000001816 cooling Methods 0.000 claims description 3
- 238000012216 screening Methods 0.000 claims description 3
- 239000000126 substance Substances 0.000 claims description 2
- 238000002386 leaching Methods 0.000 abstract description 13
- 238000004056 waste incineration Methods 0.000 abstract description 5
- 229910052793 cadmium Inorganic materials 0.000 abstract description 4
- 229910052802 copper Inorganic materials 0.000 abstract description 4
- 229910052745 lead Inorganic materials 0.000 abstract description 4
- 229910052725 zinc Inorganic materials 0.000 abstract description 4
- 238000001723 curing Methods 0.000 description 9
- 230000001988 toxicity Effects 0.000 description 8
- 231100000419 toxicity Toxicity 0.000 description 8
- 239000010813 municipal solid waste Substances 0.000 description 7
- 238000005516 engineering process Methods 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 4
- 230000000087 stabilizing effect Effects 0.000 description 4
- 239000003795 chemical substances by application Substances 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 239000013043 chemical agent Substances 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 238000000605 extraction Methods 0.000 description 2
- 239000002920 hazardous waste Substances 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 229910021487 silica fume Inorganic materials 0.000 description 2
- 239000001488 sodium phosphate Substances 0.000 description 2
- 229910000162 sodium phosphate Inorganic materials 0.000 description 2
- 230000006641 stabilisation Effects 0.000 description 2
- 238000011105 stabilization Methods 0.000 description 2
- RYFMWSXOAZQYPI-UHFFFAOYSA-K trisodium phosphate Chemical compound [Na+].[Na+].[Na+].[O-]P([O-])([O-])=O RYFMWSXOAZQYPI-UHFFFAOYSA-K 0.000 description 2
- HGUFODBRKLSHSI-UHFFFAOYSA-N 2,3,7,8-tetrachloro-dibenzo-p-dioxin Chemical compound O1C2=CC(Cl)=C(Cl)C=C2OC2=C1C=C(Cl)C(Cl)=C2 HGUFODBRKLSHSI-UHFFFAOYSA-N 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 238000009264 composting Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 208000028659 discharge Diseases 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 231100000614 poison Toxicity 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 230000004083 survival effect Effects 0.000 description 1
- 239000003440 toxic substance Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09B—DISPOSAL OF SOLID WASTE NOT OTHERWISE PROVIDED FOR
- B09B3/00—Destroying solid waste or transforming solid waste into something useful or harmless
- B09B3/40—Destroying solid waste or transforming solid waste into something useful or harmless involving thermal treatment, e.g. evaporation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09B—DISPOSAL OF SOLID WASTE NOT OTHERWISE PROVIDED FOR
- B09B5/00—Operations not covered by a single other subclass or by a single other group in this subclass
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- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Processing Of Solid Wastes (AREA)
Abstract
The invention relates to a method for treating heavy metal in stable fly ash of N-30 alkaline silica sol, which comprises the following steps: (1) preparing N-30 alkaline silica sol: sequentially adding deionized water, industrial silicon powder and sodium hydroxide into a reaction kettle according to a proportion to obtain N-30 alkaline silica sol with the particle size of about 30 nm; (2) reaction materials: weighing quantitative fly ash, adding the fly ash into a reaction kettle, sequentially adding deionized water and N-30 alkaline silica sol into the reaction kettle in sequence, and stirring to form a fly ash silica sol mixture; (3) and (3) curing: pouring the fly ash silica sol mixture into a mold to be cured for 5-10 days; (4) temperature treatment: and (4) moving the cured sample into a muffle furnace for temperature treatment. The invention adopts N-30 alkaline silica sol to solidify the fly ash, treats the fly ash at the same time, effectively reduces the leaching of heavy metals Cu, Zn, Pb and Cd in the fly ash through fully mixing with the fly ash, greatly improves the stability of the heavy metals, and realizes the harmless treatment of the waste incineration fly ash.
Description
Technical Field
The invention belongs to the field of hazardous waste treatment, and particularly relates to a method for treating heavy metal in stable fly ash of N-30 alkaline silica sol.
Background
In recent years, with the development of socio-economic, the acceleration of urbanization and the improvement of physical life of people, the annual production of municipal domestic garbage in China reaches over 1.5 hundred million tons, and the annual rate is increased by 8-10%. The municipal solid waste is treated mainly by landfill, incineration and composting. The burning method can reduce the volume of the garbage by 90 percent and 75 percent, the generated heat energy can be recycled, and the reduction, the harmlessness and the resource utilization of the household garbage can be realized to the maximum extent. However, a large amount of fly ash (about 3% -5% of the amount of the waste to be incinerated) is generated in the incineration process, and a large amount of toxic substances such as heavy metals and dioxin contained in the fly ash can be leached out under specific conditions, so that the pollution of water and soil is caused, and the serious harm is caused to the natural environment and human survival, and the fly ash is listed in national hazardous waste records. The heavy metals in the fly ash mainly comprise Cu, Zn, Pb, Cd and the like.
At present, the disposal of the waste incineration fly ash at home and abroad mainly adopts the following four methods: (1) separation and extraction technology; (2) a curing technique; (3) chemical agent stabilization techniques; (4) and (4) a heat treatment technology. The concentration of heavy metal in the leaching solution of the waste incineration fly ash is low, which is not beneficial to the separate use of the separation and extraction technology in engineering; the essence of the curing technology is that inert environment is provided to wrap the stable heavy metal, and the fly ash after curing is often subjected to capacity increase and weight increase; nowadays, the technologies with potential are chemical agent stabilization technology and heat treatment technology, but the treatment process still has some defects. Based on the problems, the inventor develops a novel curing agent which is low in cost and simple to manufacture, and reduces the leaching toxicity of the waste incineration fly ash at a lower heat treatment temperature.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: in order to solve the problems of high treatment cost, unsatisfactory treatment effect and the like of the heavy metal in the stable fly ash in the prior art, the invention provides a method for treating the heavy metal in the stable fly ash of N-30 alkaline silica sol.
The technical scheme adopted by the invention for solving the technical problems is as follows: a method for treating heavy metal in fly ash stabilized by N-30 alkaline silica sol comprises the following steps.
(1) Preparing N-30 alkaline silica sol: adding deionized water into a reaction kettle, wherein the deionized water accounts for 500 parts by weight, heating to 65-75 ℃, sequentially adding 5-8 parts of industrial silicon powder and 1-3 parts of sodium hydroxide into the reaction kettle, and keeping the temperature constant for 1 hour under the stirring condition; continuously heating to 75-85 ℃, sequentially adding 25-40 parts of industrial silicon powder and 2-4 parts of sodium hydroxide into the reaction kettle, and keeping the temperature for 2 hours under the stirring condition; and heating to 85-95 ℃ again, sequentially adding 50-60 parts of industrial silicon powder and 2-5 parts of sodium hydroxide into the reaction kettle, keeping the temperature for 3 hours under the stirring condition to obtain alkaline silica sol with the particle size of about 30nm, and naming the alkaline silica sol as N-30 alkaline silica sol according to the particle size and related chemical characteristics of the obtained silica sol.
(2) Reaction materials: weighing quantitative fly ash and adding the fly ash into a reaction kettle at room temperature, and sequentially adding deionized water and N-30 alkaline silica sol into the reaction kettle in sequence, wherein the ratio of fly ash to deionized water is 2: setting the temperature of water in a water bath kettle of the reaction kettle to be 30 ℃, stirring the water by a motor at a speed of 200-300 r/min, and stirring the water for 30 minutes to form a fly ash silica sol mixture.
(3) And (3) curing: and pouring the fly ash silica sol mixture into a mold, and curing for 5-10 days at room temperature.
(4) Temperature treatment: and (3) moving the solidified sample into a muffle furnace for temperature treatment, setting the temperature of the muffle furnace to be 500-800 ℃, taking out the sample after 2 hours, cooling, crushing, screening by using a 100-mesh sieve, and storing the screened sample.
Further, the rotating speed of stirring in the step (1) is 150-200 r/min.
Furthermore, the adding amount of the N-30 alkaline silica sol in the step (2) is 5-25% of the mass of the fly ash.
The invention has the beneficial effects that: the N-30 alkaline silica sol is used as a novel curing agent, is simple to manufacture and low in production cost, has better stabilizing effect than traditional curing agents such as sodium phosphate, silica fume and the like, can inhibit leaching of heavy metals Cu, Zn, Pb and Cd by stabilizing the heavy metals in the fly ash by adopting the sodium phosphate and the silica fume, but the leaching concentration can not meet the requirements of national standard GB 16889-2008' pollution control standard of domestic garbage landfill, still has certain discharge risk, and can meet the requirements by stabilizing the heavy metals in the fly ash by using the N-30 alkaline silica sol, thereby realizing harmless treatment of the waste incineration fly ash and reducing pollution to the surrounding environment.
Drawings
FIG. 1 is a flow chart of an embodiment of the method for treating heavy metals in fly ash stabilized by N-30 alkaline silica sol according to the invention.
Detailed Description
The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic views illustrating only the basic structure of the present invention in a schematic manner, and thus show only the constitution related to the present invention.
The best embodiment of the treatment method for stabilizing the heavy metal in the fly ash by using the N-30 alkaline silica sol has the following steps.
(1) Preparing N-30 alkaline silica sol: keeping the stirring speed of a motor at 160 r/min, adding 500g of deionized water into a reaction kettle, heating to 70 ℃, sequentially adding 6g of industrial silicon powder and 2g of sodium hydroxide into the reaction kettle, and keeping the temperature for 1 hour; continuously heating to 80 ℃, sequentially adding 30g of industrial silicon powder and 3g of sodium hydroxide into the reaction kettle, and keeping the temperature for 2 hours; and heating to 90 ℃ again, sequentially adding 55g of industrial silicon powder and 4g of sodium hydroxide into the reaction kettle, and keeping the temperature for 3 hours to obtain N-30 alkaline silica sol with the particle size of about 30 nm.
(2) Weighing 100g of fly ash and adding the fly ash into a reaction kettle at room temperature, sequentially adding 50m L deionized water and 20m L N-30 alkaline silica sol into the reaction kettle, setting the temperature of water in a water bath kettle of the reaction kettle at 30 ℃, the stirring speed of a motor at 200r/min, and stirring for 30 minutes to form a fly ash silica sol mixture.
(3) And (3) curing: the fly ash silica sol mixture was poured into a mold and cured at room temperature for 6 days.
(4) Temperature treatment: and (3) moving the solidified sample into a muffle furnace for temperature treatment, setting the temperature of the muffle furnace to be 700 ℃, taking out the sample after 2 hours, cooling, crushing, screening by using a 100-mesh sieve, and performing leaching toxicity detection on the screened sample according to the national standard.
The leaching toxicity detection result shows that the leaching concentrations of heavy metals Cu, Zn, Pb and Cd in the fly ash are respectively 5.6 mg/L, 5.27 mg/L, 0.17 mg/L and 0.11 mg/L, the leaching toxicity is lower than the Cu toxicity leaching standard of <40 mg/L, the Zn toxicity leaching standard of <100 mg/L, the Pb toxicity leaching standard of <0.25 mg/L and the Cd toxicity leaching standard of <0.15 mg/L in the national standard GB16889-2008 < pollution control Standard for municipal solid waste landfill, and the fly ash can be safely used for landfill disposal of municipal solid waste landfill.
In light of the foregoing description of the preferred embodiment of the present invention, many modifications and variations will be apparent to those skilled in the art without departing from the spirit and scope of the invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.
Claims (3)
1. A method for treating heavy metal in fly ash stabilized by N-30 alkaline silica sol is characterized by comprising the following steps:
(1) preparing N-30 alkaline silica sol: adding deionized water into a reaction kettle, wherein the deionized water accounts for 500 parts by weight, heating to 65-75 ℃, sequentially adding 5-8 parts of industrial silicon powder and 1-3 parts of sodium hydroxide into the reaction kettle, and keeping the temperature constant for 1 hour under the stirring condition; continuously heating to 75-85 ℃, sequentially adding 25-40 parts of industrial silicon powder and 2-4 parts of sodium hydroxide into the reaction kettle, and keeping the temperature for 2 hours under the stirring condition; heating to 85-95 ℃ again, sequentially adding 50-60 parts of industrial silicon powder and 2-5 parts of sodium hydroxide into the reaction kettle, keeping the temperature for 3 hours under the stirring condition to obtain alkaline silica sol with the particle size of about 30nm, and naming the alkaline silica sol as N-30 alkaline silica sol according to the particle size and related chemical characteristics of the obtained silica sol;
(2) reaction materials: weighing quantitative fly ash and adding the fly ash into a reaction kettle at room temperature, and sequentially adding deionized water and N-30 alkaline silica sol into the reaction kettle in sequence, wherein the ratio of fly ash to deionized water is 2: setting the temperature of water in a water bath kettle of a reaction kettle to be 30 ℃, stirring the water at a motor stirring speed of 200-300 r/min for 30 minutes to form fly ash silica sol mixture;
(3) and (3) curing: pouring the fly ash silica sol mixture into a mold, and curing for 5-10 days at room temperature;
(4) temperature treatment: and (3) moving the solidified sample into a muffle furnace for temperature treatment, setting the temperature of the muffle furnace to be 500-800 ℃, taking out the sample after 2 hours, cooling, crushing, screening by using a 100-mesh sieve, and storing the screened sample.
2. The method for treating the N-30 alkaline silica sol stabilized fly ash heavy metal according to claim 1, wherein the stirring speed in the step (1) is 150-200 r/min.
3. The method for treating heavy metals in fly ash stabilized by N-30 alkaline silica sol as claimed in claim 1, wherein the amount of the N-30 alkaline silica sol added in the step (2) is 5-25% of the mass of the fly ash.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010216102.2A CN111420966B (en) | 2020-03-25 | 2020-03-25 | Method for treating heavy metal in stable fly ash of N-30 alkaline silica sol |
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| CN202010216102.2A CN111420966B (en) | 2020-03-25 | 2020-03-25 | Method for treating heavy metal in stable fly ash of N-30 alkaline silica sol |
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| CN111420966A true CN111420966A (en) | 2020-07-17 |
| CN111420966B CN111420966B (en) | 2022-07-01 |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5037286A (en) * | 1988-06-24 | 1991-08-06 | Rolite, Inc. | Incineration residue treatment apparatus |
| CN1974385A (en) * | 2006-12-08 | 2007-06-06 | 中国科学院宁波材料技术与工程研究所 | Prepn process of monodispersive silica sol |
| CN104525064A (en) * | 2014-12-24 | 2015-04-22 | 中科院广州化学有限公司 | Alkaline silica sol and preparation method thereof |
| CN106903130A (en) * | 2017-03-03 | 2017-06-30 | 东南大学 | A kind of method of the middle firm incineration of refuse flyash heavy metal of warm treatment |
| CN107684688A (en) * | 2017-09-05 | 2018-02-13 | 常州大学 | A kind of high-temperature detoxification method of chromium slag |
| CN108261712A (en) * | 2018-04-02 | 2018-07-10 | 长沙绿邦环保科技有限公司 | A kind of incineration of refuse flyash curing agent, preparation method and flying dust method of disposal |
-
2020
- 2020-03-25 CN CN202010216102.2A patent/CN111420966B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5037286A (en) * | 1988-06-24 | 1991-08-06 | Rolite, Inc. | Incineration residue treatment apparatus |
| CN1974385A (en) * | 2006-12-08 | 2007-06-06 | 中国科学院宁波材料技术与工程研究所 | Prepn process of monodispersive silica sol |
| CN104525064A (en) * | 2014-12-24 | 2015-04-22 | 中科院广州化学有限公司 | Alkaline silica sol and preparation method thereof |
| CN106903130A (en) * | 2017-03-03 | 2017-06-30 | 东南大学 | A kind of method of the middle firm incineration of refuse flyash heavy metal of warm treatment |
| CN107684688A (en) * | 2017-09-05 | 2018-02-13 | 常州大学 | A kind of high-temperature detoxification method of chromium slag |
| CN108261712A (en) * | 2018-04-02 | 2018-07-10 | 长沙绿邦环保科技有限公司 | A kind of incineration of refuse flyash curing agent, preparation method and flying dust method of disposal |
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| CN111420966B (en) | 2022-07-01 |
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Effective date of registration: 20230419 Address after: 213164 711-2, floor 7, plant 10, Changzhou Innovation Park, Israel, China, No. 18-67, middle Changwu Road, Wujin District, Changzhou City, Jiangsu Province Patentee after: Xianglai (Changzhou) energy saving Technology Co.,Ltd. Address before: 213164 Changzhou University, 21 Gehu Road, Wujin District, Changzhou City, Jiangsu Province Patentee before: CHANGZHOU University |
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