CN112570432B - Dechlorination method for coal-fired power plant desulfurization wastewater drying ash - Google Patents
Dechlorination method for coal-fired power plant desulfurization wastewater drying ash Download PDFInfo
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- 238000000034 method Methods 0.000 title claims abstract description 40
- 238000006298 dechlorination reaction Methods 0.000 title claims abstract description 29
- 238000001035 drying Methods 0.000 title claims abstract description 26
- 238000006477 desulfuration reaction Methods 0.000 title claims abstract description 23
- 230000023556 desulfurization Effects 0.000 title claims abstract description 23
- 239000002351 wastewater Substances 0.000 title claims abstract description 21
- 238000005406 washing Methods 0.000 claims abstract description 58
- 239000002253 acid Substances 0.000 claims abstract description 55
- 238000000967 suction filtration Methods 0.000 claims abstract description 30
- 230000010355 oscillation Effects 0.000 claims abstract description 27
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 27
- 238000005303 weighing Methods 0.000 claims abstract description 9
- 238000000498 ball milling Methods 0.000 claims abstract description 3
- 238000007873 sieving Methods 0.000 claims abstract description 3
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 claims description 36
- 239000007788 liquid Substances 0.000 claims description 31
- 239000008367 deionised water Substances 0.000 claims description 17
- 229910021641 deionized water Inorganic materials 0.000 claims description 17
- 239000000243 solution Substances 0.000 claims description 16
- 238000003756 stirring Methods 0.000 claims description 15
- 239000011259 mixed solution Substances 0.000 claims description 14
- 239000000919 ceramic Substances 0.000 claims description 11
- 230000000382 dechlorinating effect Effects 0.000 claims description 11
- 238000003760 magnetic stirring Methods 0.000 claims description 8
- 238000004506 ultrasonic cleaning Methods 0.000 claims description 8
- 238000001816 cooling Methods 0.000 claims description 7
- 238000000926 separation method Methods 0.000 claims description 6
- 238000010438 heat treatment Methods 0.000 claims description 3
- 238000004321 preservation Methods 0.000 claims description 2
- 239000002893 slag Substances 0.000 abstract description 22
- 238000004140 cleaning Methods 0.000 abstract description 11
- 239000002699 waste material Substances 0.000 abstract description 11
- 238000001354 calcination Methods 0.000 abstract description 10
- 230000000694 effects Effects 0.000 abstract description 7
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 abstract description 6
- 230000002349 favourable effect Effects 0.000 abstract description 3
- 230000009286 beneficial effect Effects 0.000 abstract description 2
- 238000005554 pickling Methods 0.000 abstract description 2
- 238000002604 ultrasonography Methods 0.000 abstract 1
- 239000002956 ash Substances 0.000 description 55
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 19
- 239000000460 chlorine Substances 0.000 description 19
- 229910052801 chlorine Inorganic materials 0.000 description 19
- 230000000052 comparative effect Effects 0.000 description 15
- 239000010881 fly ash Substances 0.000 description 7
- 239000000203 mixture Substances 0.000 description 6
- 238000009210 therapy by ultrasound Methods 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 4
- 238000005245 sintering Methods 0.000 description 4
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 3
- 239000003546 flue gas Substances 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 150000003839 salts Chemical class 0.000 description 3
- SQGYOTSLMSWVJD-UHFFFAOYSA-N silver(1+) nitrate Chemical compound [Ag+].[O-]N(=O)=O SQGYOTSLMSWVJD-UHFFFAOYSA-N 0.000 description 3
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 238000009835 boiling Methods 0.000 description 2
- 150000001805 chlorine compounds Chemical class 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 239000000706 filtrate Substances 0.000 description 2
- 229910052602 gypsum Inorganic materials 0.000 description 2
- 239000010440 gypsum Substances 0.000 description 2
- 238000010248 power generation Methods 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 239000011593 sulfur Substances 0.000 description 2
- 229910052717 sulfur Inorganic materials 0.000 description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 238000010170 biological method Methods 0.000 description 1
- 150000003841 chloride salts Chemical class 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 231100001261 hazardous Toxicity 0.000 description 1
- 229910001385 heavy metal Inorganic materials 0.000 description 1
- 229910001504 inorganic chloride Inorganic materials 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 238000000053 physical method Methods 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 239000012086 standard solution Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000004448 titration Methods 0.000 description 1
- 238000004056 waste incineration Methods 0.000 description 1
- 238000004065 wastewater treatment Methods 0.000 description 1
- -1 water washing Chemical compound 0.000 description 1
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- 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
-
- 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
-
- 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
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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 dechlorination method for coal-fired power plant desulfurization wastewater dried ash, which comprises the following steps: weighing certain mass of ash, drying, ball-milling and sieving the ash, placing the obtained ash in a beaker, and adding an acid solution for acid washing. The invention has the beneficial effects that: the invention adopts acid cleaning and calcination as dechlorination methods, removes water-soluble chloride by acid cleaning dechlorination and ultrasonic oscillation, then carries out suction filtration on ash slag after acid cleaning centrifugal ultrasound, calcines dried ash slag after suction filtration, can simply and conveniently remove insoluble chloride and a small amount of organic matters, and has the dechlorination effect of 98.1 percent; the method is favorable for resource utilization of the dried ash after dechlorination, and a large amount of water can be saved by acid washing. The waste acid can be used for pickling the dried ash, and the waste acid has high concentration, so that the dechlorination effect is better, and the cost is saved. Can also be extended to the treatment of dried ash slag by utilizing waste acid and the like produced in industry, thereby achieving the effect of treating waste by waste.
Description
Technical Field
The invention belongs to the field of desulfurization of coal-fired power plants, and particularly relates to a dechlorination method for desulfurization wastewater drying ash residues of a coal-fired power plant.
Background
Coal-fired power generation is the most main thermal power generation mode in China at present, and the problem of desulfurization of coal-fired flue gas becomes the key of air treatment. Wherein the limestone-gypsum wet flue gas desulfurization technology accounts for the highest percentage in the coal-fired flue gas desulfurization treatment, and exceeds 75%. The limestone-gypsum wet process converts gaseous sulfur to other forms of sulfur, but produces environmentally hazardous desulfurized waste water in the process. The desulfurization wastewater has complex components, high salt content and extremely difficult treatment, and the direct discharge can cause great harm to water quality and soil. Aiming at the problem, a plurality of desulfurization wastewater treatment methods such as a physical method, a chemical method, a biological method, a zero discharge technology and the like are proposed at home and abroad. Wherein, the zero emission technology gives consideration to resource saving and environmental protection, and becomes a research hotspot. The flue evaporation method is a novel zero-emission technology, and the desulfurized wastewater is directly atomized and evaporated to combine the separated salts with the fly ash, so that not only is the dried ash obtained, but also the water consumption is greatly reduced, and the treatment cost is reduced.
There are many methods for removing chlorine including water washing, calcination, acid washing, metal oxide dechlorination, organic dechlorination, etc. The water-soluble chlorine can be removed by water washing. The acid may react with some of the insoluble chlorine during acid washing to convert it to soluble chlorine. Calcination may evaporate some of the soluble chloride salts and decompose some of the insoluble chloride, enhancing dechlorination.
The removal of chloride ions by combinatorial methods has been reported and is described in the following references:
the behavior research of incineration fly ash pretreatment process and inorganic chloride thereof published in environmental science in 2013 by cinnofen introduces a combination method: washing and sintering (WCCB), and taking the stability of heavy metal and the decomposition of organic matters into consideration. After the fly ash is treated by washing and sintering twice, the chlorine is reduced by more than 94 percent, and the efficiency is higher; the method has the advantages of small wastewater amount and high salt content, and is favorable for secondary utilization of resources.
Secondly, the patent is named as a high-efficiency dechlorinating agent and a dechlorinating method and device for waste incineration fly ash, and the patent with the application number of CN202010222818.3 discloses a dechlorinating method for adding acid by washing, wherein the dechlorinating agent consisting of acid is added into the fly ash in a specially designed electric field device, then the fly ash is washed by water, the stirring is kept, and the current is introduced for 20-120 min to obtain the fly ash after dechlorination.
The dechlorination is carried out by using the 'washing and sintering' in the first step, which shows that the high dechlorination rate cannot be achieved by single washing or sintering, and the dechlorination agent consisting of acid is used in the second step, which shows that the acid washing can better leach out insoluble chlorine. Therefore, the method of acid washing and calcining can be used for more effectively removing chlorine.
Aiming at the problems of large yield, difficult treatment and resource waste caused by large accumulation of the dried ash of the desulfurization wastewater of the coal-fired power plant at present, the dried ash can be well recycled after dechlorination. However, the use of a single chlorine removal method has a problem of low chlorine removal rate.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provides a dechlorination method for drying ash slag of desulfurization wastewater of a coal-fired power plant.
The chlorine removal method for the coal-fired power plant desulfurization wastewater drying ash comprises the following steps:
step 1, weighing certain mass of ash, drying, ball-milling and sieving the ash, placing the obtained ash in a beaker, and adding an acid solution for acid washing; stirring the mixed solution after the acid washing in a magnetic stirrer at room temperature, then pouring the mixed solution into a centrifuge tube, and carrying out centrifugal separation for 10-30 min at the rotating speed of 200-2000 r/min; pouring the washing liquid, continuously adding acid liquid into the centrifugal tube, and placing the centrifugal tube into an ultrasonic cleaning machine for ultrasonic oscillation for 5-15 min; then pouring the mixed solution after ultrasonic oscillation into a beaker for magnetic stirring; sequentially repeating the acid washing, the stirring, the centrifugal separation and the ultrasonic oscillation for 1-3 times;
step 2, removing the washing liquid of acid washing, adding deionized water into a centrifugal tube, and then carrying out ultrasonic oscillation for 5-15 min; then, carrying out suction filtration by using a Buchner funnel and qualitative filter paper; washing with deionized water again after suction filtration, and performing suction filtration for 1-3 times to obtain filter residue; putting the filter residue into an oven, and drying at 105-160 ℃ to constant weight to obtain acid-washed dried ash;
step 3, placing the acid-washed dried ash obtained in the step 2 into a crucible, placing the crucible into a muffle furnace, heating the muffle furnace to 600-900 ℃ at a normal speed, and then preserving heat for 1-4 hours; clamping the crucible out by using a crucible clamp, covering the crucible cover, and cooling the crucible in a dryer to room temperature to obtain acid-washed and calcined dried ash.
Preferably, the ash weighed in the step 1 is 2-10 g in mass.
Preferably, the acid solution in the step 1 is an acetic acid solution prepared by deionized water in a concentration of 0.2-0.8 mol/L, and the solid-to-liquid ratio of the ash to the acetic acid solution is 1: 5-1: 20.
Preferably, the concentration of the acetic acid solution is 0.6-0.8 mol/L, and the solid-to-liquid ratio of the ash residue to the acetic acid solution is 1: 5-1: 15.
Preferably, the stirring time of the mixed solution after the acid washing in the step 1 in a magnetic stirrer is 5-15 min, and the centrifugal speed of a centrifugal tube is 500-1000 r/min; the duration of ultrasonic oscillation is 5-10 min.
Preferably, in the step 1, the acid washing, the stirring, the centrifugal separation and the ultrasonic oscillation are repeated for 1-2 times.
Preferably, the temperature of the oven in step 2 is 105 ℃.
Preferably, the crucible in step 3 is a ceramic crucible.
Preferably, the temperature of the muffle furnace after the temperature rise in the step 3 is 650-750 ℃, and the heat preservation time of the crucible in the muffle furnace is 1-2 h.
The invention has the beneficial effects that: the invention provides a high-efficiency dechlorination method, which adopts acid washing and calcination as dechlorination methods, removes water-soluble chlorides by acid washing dechlorination and ultrasonic oscillation, performs suction filtration on ash slag subjected to acid washing centrifugal ultrasonic treatment, and calcines dried ash slag subjected to suction filtration, can simply and conveniently remove insoluble chlorides and a small amount of organic matters, and has a dechlorination effect of 98.1 percent; the method is favorable for resource utilization of the dried ash after dechlorination, and a large amount of water can be saved by acid washing. The waste acid can be used for pickling the dried ash, and the waste acid has high concentration, so that the dechlorination effect is better, and the cost is saved. Can also be extended to the treatment of dried ash slag by utilizing waste acid and the like produced in industry, thereby achieving the effect of treating waste by waste.
Drawings
FIG. 1 is a flow chart of a method for removing chlorine from desulfurization wastewater drying ash of a coal-fired power plant.
Detailed Description
The present invention will be further described with reference to the following examples. The following examples are set forth merely to aid in the understanding of the invention. It should be noted that, for a person skilled in the art, several modifications can be made to the invention without departing from the principle of the invention, and these modifications and modifications also fall within the protection scope of the claims of the present invention.
The invention provides a dechlorination method for coal-fired power plant desulfurization wastewater drying ash, which has a flow chart as shown in figure 1: acid washing and calcination are adopted as dechlorination methods, water-soluble chloride is removed through acid washing dechlorination and ultrasonic oscillation, then ash obtained after acid washing centrifugal ultrasonic is subjected to suction filtration, and dried ash obtained after suction filtration is calcined, so that insoluble chloride and a small amount of organic matters can be simply and conveniently removed.
Example 1:
3g of ash slag which is sieved by a dry ball mill is weighed to be 0.1g accurately, the ash slag is placed in a 100ml beaker, and acid cleaning is carried out by using 0.8mol/L acetic acid solution according to the solid-to-liquid ratio of 1: 10. Stirring in a magnetic stirrer at room temperature for 5min, pouring the mixed solution into a centrifuge tube, and centrifuging at 1000r/min for 15 min. Pouring off the washing liquid, continuously adding the acid liquid into the centrifuge tube, placing the centrifuge tube in an ultrasonic cleaning machine for ultrasonic oscillation for 10min, then pouring the mixture into a beaker for magnetic stirring for 10min, and then repeating the steps for centrifugal ultrasonic treatment.
Removing the washing liquid, adding deionized water into the centrifuge tube, performing ultrasonic oscillation for 10min, performing suction filtration with Buchner funnel and qualitative filter paper, and cleaning and suction filtration for 2 times after suction filtration to obtain filter residue. And (3) drying the filter residue in an oven at 105 ℃ to constant weight to obtain acid-washed dried ash.
Placing the obtained acid-washed dried ash in a ceramic crucible, placing the ceramic crucible in a muffle furnace, raising the temperature of the muffle furnace to 700 ℃ at a normal speed, and then preserving the heat for 2 hours. Clamping the crucible out by using a crucible clamp, covering the crucible cover, and cooling the crucible cover in a dryer to room temperature to obtain the acid-washed and calcined dried ash.
Example 2:
3g of ash slag which is sieved by a dry ball mill is weighed to be 0.1g accurately, the ash slag is placed in a 100ml beaker, and acid washing is carried out by using 0.6mol/L acetic acid solution according to the solid-to-liquid ratio of 1: 15. Stirring in a magnetic stirrer for 5min at room temperature, pouring the mixed solution into a centrifuge tube, and centrifuging at 500r/min for 20 min. Pouring off the washing liquid, continuously adding the acid liquid into the centrifuge tube, placing the centrifuge tube in an ultrasonic cleaning machine for ultrasonic oscillation for 10min, then pouring the mixture into a beaker for magnetic stirring for 10min, and then repeating the steps for centrifugal ultrasonic treatment.
Removing the washing liquid, adding deionized water into the centrifuge tube, performing ultrasonic oscillation for 10min, performing suction filtration with Buchner funnel and qualitative filter paper, and cleaning and suction filtration for 1 time after suction filtration to obtain filter residue. And (3) drying the filter residue in an oven at 105 ℃ to constant weight to obtain acid-washed dried ash.
Placing the obtained acid-washed dried ash in a ceramic crucible, placing the ceramic crucible in a muffle furnace, raising the temperature of the muffle furnace to 650 ℃ at a normal speed, and then preserving the heat for 1 h. Clamping the crucible out by using a crucible clamp, covering the crucible cover, and cooling the crucible cover in a dryer to room temperature to obtain the acid-washed and calcined dried ash.
Example 2:
3g of ash slag which is sieved by a dry ball mill is weighed to be 0.1g accurately, the ash slag is placed in a 100ml beaker, and acid washing is carried out by using 0.7mol/L acetic acid solution according to the solid-to-liquid ratio of 1: 5. Stirring in a magnetic stirrer for 5min at room temperature, pouring the mixed solution into a centrifuge tube, and centrifuging at 750r/min for 20 min. Pouring off the washing liquid, continuously adding the acid liquid into the centrifuge tube, placing the centrifuge tube in an ultrasonic cleaning machine for ultrasonic oscillation for 10min, then pouring the mixture into a beaker for magnetic stirring for 10min, and then repeating the steps for centrifugal ultrasonic treatment.
Removing the washing liquid, adding deionized water into the centrifuge tube, performing ultrasonic oscillation for 10min, performing suction filtration with Buchner funnel and qualitative filter paper, and cleaning and suction filtration for 3 times after suction filtration to obtain filter residue. And (3) drying the filter residue in an oven at 105 ℃ to constant weight to obtain acid-washed dried ash.
And (3) placing the obtained acid-washed dried ash in a ceramic crucible, placing the ceramic crucible into a muffle furnace, raising the temperature of the muffle furnace to 750 ℃ at a normal speed, and then preserving the heat for 1 h. Clamping the crucible out by using a crucible clamp, covering the crucible cover, and cooling the crucible cover in a dryer to room temperature to obtain the acid-washed and calcined dried ash.
Comparative example
Comparative examples chlorine removal was carried out by using a single chlorine removal method including a single washing, acid washing, calcination, etc. and a combined washing and calcination method, respectively.
Comparative example 1:
weighing 2g of ash slag which is sieved by a dry ball mill, accurately weighing the ash slag to 0.1g, placing the ash slag in a 100ml beaker, and washing the ash slag by deionized water according to a solid-to-liquid ratio of 1: 10. Stirring in a magnetic stirrer for 5min at room temperature, pouring the mixed solution into a centrifuge tube, and centrifuging at 1000r/min for 20 min. Pouring off the washing liquid, continuously adding deionized water into the centrifuge tube, placing the centrifuge tube in an ultrasonic cleaning machine for ultrasonic oscillation for 10min, then pouring the mixture into a beaker for magnetic stirring for 10min, and then repeating the steps for centrifugal ultrasonic.
Removing the washing liquid, adding deionized water into the centrifuge tube, performing ultrasonic oscillation for 10min, performing suction filtration with Buchner funnel and qualitative filter paper, and cleaning and suction filtration for 2 times after suction filtration to obtain filter residue. And (3) drying the filter residue in an oven at 105 ℃ to constant weight to obtain the water-washed dried ash.
Comparative example 2:
2g of ash slag which is sieved by a dry ball mill is weighed to be 0.1g accurately, the ash slag is placed in a 100ml beaker, and acid cleaning is carried out by using 0.8mol/L acetic acid solution according to the solid-to-liquid ratio of 1: 10. Stirring in a magnetic stirrer for 5min at room temperature, pouring the mixed solution into a centrifuge tube, and centrifuging at 1000r/min for 20 min. Pouring off the washing liquid, continuously adding the acid liquid into the centrifuge tube, placing the centrifuge tube in an ultrasonic cleaning machine for ultrasonic oscillation for 10min, then pouring the mixture into a beaker for magnetic stirring for 10min, and then repeating the steps for centrifugal ultrasonic treatment.
Removing the washing liquid, adding deionized water into the centrifuge tube, performing ultrasonic oscillation for 10min, performing suction filtration with Buchner funnel and qualitative filter paper, and cleaning and suction filtration for 2 times after suction filtration to obtain filter residue. And (3) drying the filter residue in an oven at 105 ℃ to constant weight to obtain acid-washed dried ash.
Comparative example 3:
weighing about 2g of dry ball-milled and sieved ash, accurately weighing to 0.1g, placing in a ceramic crucible, placing in a muffle furnace, raising the temperature of the muffle furnace to 700 ℃ at a normal speed, and then preserving the heat for 2 h. Clamping the crucible out by using a crucible clamp, covering the crucible cover, and cooling the crucible cover in a dryer to room temperature to obtain calcined dry ash.
Comparative example 4:
3g of ash slag which is sieved by a dry ball mill is weighed to be 0.1g accurately, and the ash slag is placed in a 100ml beaker and washed by deionized water according to the solid-to-liquid ratio of 1: 10. Stirring in a magnetic stirrer for 5min at room temperature, pouring the mixed solution into a centrifuge tube, and centrifuging at 1000r/min for 20 min. Pouring off the washing liquid, continuously adding deionized water into the centrifuge tube, placing the centrifuge tube in an ultrasonic cleaning machine for ultrasonic oscillation for 10min, then pouring the mixture into a beaker for magnetic stirring for 10min, and then repeating the steps for centrifugal ultrasonic.
Removing the washing liquid, adding deionized water into the centrifuge tube, performing ultrasonic oscillation for 10min, performing suction filtration with Buchner funnel and qualitative filter paper, and cleaning and suction filtration for 2 times after suction filtration to obtain filter residue. And (3) drying the filter residue in an oven at 105 ℃ to constant weight to obtain the water-washed dried ash.
Placing the obtained acid-washed dried ash in a ceramic crucible, placing the ceramic crucible in a muffle furnace, raising the temperature of the muffle furnace to 700 ℃ at a normal speed, and then preserving the heat for 2 hours. Clamping the crucible out by using a crucible clamp, covering the crucible cover, and cooling the crucible cover in a dryer to room temperature to obtain the dried ash slag which is washed by water and calcined.
Dechlorination test experiment:
weighing 1g of sample, accurately weighing the sample to 0.1g, placing the sample in a 100ml beaker, adding deionized water and nitric acid for extraction, heating and boiling, and slightly boiling for 1-2 min. Filter with quick filter paper, collect the filtrate in 100ml volumetric flask, dilute to the mark with water, shake up. Accurately transferring 10ml of filtrate, injecting into a conical flask, adjusting the pH value to be 6.5-10.5, and adding 1ml of 5% KCrO4The AgNO3 standard solution was added dropwise until the brick-red precipitate appeared and did not disappear, indicating that the titration end point had been reached, and the results of the experiment are shown in table 1.
TABLE 1 Experimental results of example 1 and comparative examples 1-4
| Sample (I) | Chlorine removal Rate (%) |
| Example 1 | 98.1 |
| Example 2 | 95.4 |
| Example 3 | 96.7 |
| Comparative example 1 | 71.4 |
| Comparative example 2 | 86.1 |
| Comparative example 3 | 89.5 |
| Comparative example 4 | 92.3 |
The analysis of the results of chlorine removal rate measurements of examples 1 to 3 and comparative examples 1 to 3 in Table 1 shows that: the chlorine removal rates of examples 1-3 were higher than those of comparative examples 1-3, indicating that the combined chlorine removal process of the examples was better than the single chlorine removal process of the comparative examples. And the analysis and comparison of the chlorine removal rate detection results of the embodiments 1 to 3 and the comparative example 4 show that the combined method of acid washing and calcining has better effect than the combined method of water washing and calcining.
Claims (8)
1. A dechlorination method for coal-fired power plant desulfurization wastewater drying ash is characterized by comprising the following steps:
step 1, weighing certain mass of ash, drying, ball-milling and sieving the ash, placing the obtained ash in a beaker, adding an acid solution for acid washing, wherein the acid solution is an acetic acid solution prepared by deionized water at a ratio of ash to acetic acid solution of 1: 5-1: 20; stirring the mixed solution after the acid washing in a magnetic stirrer at room temperature, then pouring the mixed solution into a centrifuge tube, and carrying out centrifugal separation for 10-30 min at the rotating speed of 200-2000 r/min; pouring the washing liquid, continuously adding acid liquid into the centrifugal tube, and placing the centrifugal tube into an ultrasonic cleaning machine for ultrasonic oscillation for 5-15 min; then pouring the mixed solution after ultrasonic oscillation into a beaker for magnetic stirring; sequentially repeating the acid washing, the stirring, the centrifugal separation and the ultrasonic oscillation for 1-3 times;
step 2, removing the washing liquid of acid washing, adding deionized water into a centrifugal tube, and then carrying out ultrasonic oscillation for 5-15 min; then, carrying out suction filtration by using a Buchner funnel and qualitative filter paper; washing with deionized water again after suction filtration, and performing suction filtration for 1-3 times to obtain filter residue; putting the filter residue into an oven, and drying at 105-160 ℃ to constant weight to obtain acid-washed dried ash;
step 3, placing the acid-washed dried ash obtained in the step 2 into a crucible, placing the crucible into a muffle furnace, heating the muffle furnace to 700-900 ℃ at a normal speed, and then preserving heat for 1-4 hours; clamping the crucible out by using a crucible clamp, covering the crucible cover, and cooling the crucible in a dryer to room temperature to obtain acid-washed and calcined dried ash.
2. The method for dechlorinating the coal-fired power plant desulfurization wastewater drying ash according to claim 1, which is characterized by comprising the following steps: the ash weighed in the step 1 is 2-10 g in mass.
3. The method for dechlorinating the coal-fired power plant desulfurization wastewater drying ash according to claim 1, which is characterized by comprising the following steps: the concentration of the acetic acid solution is 0.6-0.8 mol/L, and the solid-to-liquid ratio of the ash residue to the acetic acid solution is 1: 5-1: 15.
4. The method for dechlorinating the coal-fired power plant desulfurization wastewater drying ash according to claim 1, which is characterized by comprising the following steps: stirring the mixed solution after the acid washing in the step 1 in a magnetic stirrer for 5-15 min, wherein the centrifugal speed of a centrifugal tube is 500-1000 r/min; the duration of ultrasonic oscillation is 5-10 min.
5. The method for dechlorinating the coal-fired power plant desulfurization wastewater drying ash according to claim 1, which is characterized by comprising the following steps: and (3) repeating the acid washing, stirring, centrifugal separation and ultrasonic oscillation for 1-2 times in the step 1.
6. The method for dechlorinating the coal-fired power plant desulfurization wastewater drying ash according to claim 1, which is characterized by comprising the following steps: the oven temperature in step 2 was 105 ℃.
7. The method for dechlorinating the coal-fired power plant desulfurization wastewater drying ash according to claim 1, which is characterized by comprising the following steps: the crucible in the step 3 is a ceramic crucible.
8. The method for dechlorinating the coal-fired power plant desulfurization wastewater drying ash according to claim 1, which is characterized by comprising the following steps: and 3, the temperature of the muffle furnace after the temperature rise in the step 3 is 700-750 ℃, and the heat preservation time of the crucible in the muffle furnace is 1-2 h.
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| JPH10132233A (en) * | 1996-10-30 | 1998-05-22 | Takuma Co Ltd | Apparatus and method for burning to dispose waste |
| JP2000285756A (en) * | 1999-03-30 | 2000-10-13 | Densen Sogo Gijutsu Center | Dechlorination method of coating waste of vinyl chloride coated wire |
| JP2005058974A (en) * | 2003-08-20 | 2005-03-10 | National Institute Of Advanced Industrial & Technology | Method for detoxifying dioxins in incineration ash |
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Inventor after: Chen Biao Inventor after: Sheng Jiawei Inventor after: Sun Min Inventor after: Sun Qing Inventor after: Zhang Jian Inventor after: Qin Ganghua Inventor after: Tong Xiaozhong Inventor after: Ye Qing Inventor after: Zhang Lin Inventor after: Lei Shiyi Inventor after: Yu Sanchuan Inventor after: Chen Yufan Inventor after: Feng Xiangdong Inventor before: Chen Biao Inventor before: Tong Xiaozhong Inventor before: Lei Shiyi Inventor before: Chen Yufan Inventor before: Feng Xiangdong Inventor before: Sheng Jiawei Inventor before: Sun Min Inventor before: Sun Qing Inventor before: Zhang Jian |