CN113953303A - Method for reinforced washing of fly ash and resource utilization of high-salinity wastewater - Google Patents
Method for reinforced washing of fly ash and resource utilization of high-salinity wastewater Download PDFInfo
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- 238000005406 washing Methods 0.000 title claims abstract description 100
- 239000010881 fly ash Substances 0.000 title claims abstract description 85
- 238000000034 method Methods 0.000 title claims abstract description 18
- 239000002351 wastewater Substances 0.000 title claims abstract description 10
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 96
- 239000007788 liquid Substances 0.000 claims abstract description 79
- 229910001385 heavy metal Inorganic materials 0.000 claims abstract description 43
- XAEFZNCEHLXOMS-UHFFFAOYSA-M potassium benzoate Chemical compound [K+].[O-]C(=O)C1=CC=CC=C1 XAEFZNCEHLXOMS-UHFFFAOYSA-M 0.000 claims abstract description 23
- 238000010438 heat treatment Methods 0.000 claims abstract description 16
- 159000000000 sodium salts Chemical class 0.000 claims abstract description 16
- 239000002699 waste material Substances 0.000 claims abstract description 16
- 150000003839 salts Chemical class 0.000 claims abstract description 15
- 238000000926 separation method Methods 0.000 claims abstract description 12
- 238000001816 cooling Methods 0.000 claims abstract description 9
- 239000008236 heating water Substances 0.000 claims abstract description 8
- 239000002244 precipitate Substances 0.000 claims abstract description 8
- 238000005728 strengthening Methods 0.000 claims abstract description 5
- 239000002002 slurry Substances 0.000 claims description 26
- 238000002156 mixing Methods 0.000 claims description 24
- 238000000967 suction filtration Methods 0.000 claims description 12
- 238000001704 evaporation Methods 0.000 claims description 11
- 238000003756 stirring Methods 0.000 claims description 8
- 238000004140 cleaning Methods 0.000 claims description 6
- 239000000126 substance Substances 0.000 claims description 5
- 230000001376 precipitating effect Effects 0.000 claims description 4
- 210000004911 serous fluid Anatomy 0.000 claims description 4
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 abstract description 3
- 150000001450 anions Chemical class 0.000 abstract description 3
- 239000008394 flocculating agent Substances 0.000 abstract description 3
- 150000002500 ions Chemical class 0.000 abstract description 3
- 239000012633 leachable Substances 0.000 abstract description 3
- 229910052700 potassium Inorganic materials 0.000 abstract description 3
- 239000011591 potassium Substances 0.000 abstract description 3
- 229910001338 liquidmetal Inorganic materials 0.000 abstract description 2
- 159000000001 potassium salts Chemical class 0.000 abstract 2
- 238000011084 recovery Methods 0.000 abstract 1
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 18
- 239000004568 cement Substances 0.000 description 9
- 239000011780 sodium chloride Substances 0.000 description 9
- 230000000694 effects Effects 0.000 description 7
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M Potassium chloride Chemical compound [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 description 6
- 230000008020 evaporation Effects 0.000 description 6
- 238000005189 flocculation Methods 0.000 description 6
- 230000016615 flocculation Effects 0.000 description 6
- 238000001556 precipitation Methods 0.000 description 6
- 230000008569 process Effects 0.000 description 6
- 239000002994 raw material Substances 0.000 description 6
- 238000004056 waste incineration Methods 0.000 description 5
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 4
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 4
- 239000002920 hazardous waste Substances 0.000 description 4
- 230000008859 change Effects 0.000 description 3
- 238000002425 crystallisation Methods 0.000 description 3
- 230000008025 crystallization Effects 0.000 description 3
- 230000002708 enhancing effect Effects 0.000 description 3
- 230000001965 increasing effect Effects 0.000 description 3
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 3
- 239000001103 potassium chloride Substances 0.000 description 3
- 235000011164 potassium chloride Nutrition 0.000 description 3
- 239000012716 precipitator Substances 0.000 description 3
- 238000004064 recycling Methods 0.000 description 3
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000011033 desalting Methods 0.000 description 2
- 239000000428 dust Substances 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000003344 environmental pollutant Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 231100000719 pollutant Toxicity 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
- 239000002253 acid Substances 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 239000004566 building material Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 229910052681 coesite Inorganic materials 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 229910052593 corundum Inorganic materials 0.000 description 1
- 229910052906 cristobalite Inorganic materials 0.000 description 1
- 238000010612 desalination reaction Methods 0.000 description 1
- 238000011038 discontinuous diafiltration by volume reduction Methods 0.000 description 1
- 238000010828 elution Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 230000036571 hydration Effects 0.000 description 1
- 238000006703 hydration reaction Methods 0.000 description 1
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 description 1
- 229910000041 hydrogen chloride Inorganic materials 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 239000000779 smoke Substances 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 229910052682 stishovite Inorganic materials 0.000 description 1
- 230000001988 toxicity Effects 0.000 description 1
- 231100000419 toxicity Toxicity 0.000 description 1
- 229910052905 tridymite Inorganic materials 0.000 description 1
- 229910001845 yogo sapphire Inorganic materials 0.000 description 1
Images
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09B—DISPOSAL OF SOLID WASTE
- 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
- B09B5/00—Operations not covered by a single other subclass or by a single other group in this subclass
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F9/00—Multistage treatment of water, waste water or sewage
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/02—Treatment of water, waste water, or sewage by heating
- C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
- C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
- C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
- C02F1/54—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using organic material
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/20—Heavy metals or heavy metal compounds
Abstract
The invention adopts a method for strengthening water washing of fly ash and resource utilization of high-salinity wastewater, firstly, the fly ash is subjected to water bath heating water washing, the heating temperature is 50-60 ℃, the water bath heating water washing mode can efficiently remove a large amount of leachable anions and heavy metal ions in the fly ash, and most heavy metals are washed out, so that washing liquid and harmless fly ash are obtained; the washing liquid is subjected to removal of heavy metal precipitates in the washing liquid in a mode of combining inorganic-organic flocculants to obtain purified high-salt water washing liquid and heavy metal precipitates, wherein the removal rate of total heavy metals in the washing liquid can reach 99%; the purified high-salt water washing liquor contains about 6wt% -15wt% of potassium and sodium salts, the high-salt water washing liquor is evaporated and crystallized through an MVR evaporator, the potassium salt is crystallized through cooling, potassium salt and mixed salt waste liquor are obtained through centrifugal separation, the mixed salt waste liquor is electrolyzed to obtain the sodium salts, the recovery of the potassium salts and the sodium salts is realized, and the vacancy of the potassium salts in China can be relieved.
Description
Technical Field
The invention belongs to the technical field of harmless treatment of fly ash generated by waste incineration, and particularly relates to a method for enhancing washing of fly ash and resource utilization of high-salinity wastewater.
Background
The waste incineration fly ash in China has huge yield, and the waste incineration industry will grow explosively with the increase of the clean transportation volume of the household garbage and the increase of the incineration treatment proportion. By the end of 2020, the total incineration amount of the garbage reaches 59.14 ten thousand tons/day, in the process of garbage incineration, a lot of harmful substances, such as dioxin, acid gases (such as hydrogen chloride and sulfur dioxide), nitrogen oxides, heavy metal dust and the like, can be generated, most of the pollutants can be intercepted by a dust removal system to form fly ash when the smoke purification is carried out on the pollutants, the generation amount of the fly ash generated by garbage incineration is 2% -5% of the mass of the original garbage, and the amount of the fly ash generated in the year is about 1000 ten thousand tons.
In 2008, the national hazardous waste record revised definitely that the household garbage incineration fly ash belongs to hazardous waste and has toxicity, the hazardous waste category is HW18, and the household garbage incineration fly ash needs to be subjected to harmless treatment before disposal. The current fly ash harmless treatment means mainly focus on solidification and stabilization, and cement is one of the most common hazardous waste stabilizers. The fly ash is added with cement which accounts for 10-20% of the mass of the fly ash, and heavy metals contained in the fly ash are converted into stable hydroxide by utilizing the strong basicity (the pH value is about 12) of the cement, so that the effect of preventing the heavy metals from dissolving out is very good, and although the cement is solidified to realize the harmlessness of the fly ash, the treated fly ash needs to enter a landfill site for disposal, and the volume reduction of the fly ash cannot be realized. The large and medium-sized urban fly ash has large production amount and tense land resources, the disposal mode mainly based on landfill is under greater and greater pressure, and with the increase of the total capacity of the waste incineration fly ash and the trend of the saturation of the landfill disposal space, the resource, reduction and harmless treatment of the waste incineration fly ash are the final trend, so how to reasonably utilize the fly ash and realize the reutilization of waste resources is urgent.
The main components of the fly ash are CaO and Al2O3、SiO2The content of the hydrochloride and partial heavy metals in the fly ash are reduced, so that the key problem of fly ash resource utilization is that the raw materials are basically consistent with the raw materials required for manufacturing cement or other building materials, but the large amount of the hydrochloride in the fly ash can block the hydration action of the cement, and the volatile heavy metals can cause the blockage of a cement kiln. However, in order to achieve a good elution effect by the conventional washing technology, the washing times or washing strength needs to be increased, and a large amount of water resources are consumed.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention provides a method for strengthening water washing of fly ash and resource utilization of high-salinity wastewater, which mainly solves the technical problems that: the existing fly ash washing process is difficult to achieve the effect of efficiently eluting hydrochloride and heavy metals, and needs to be realized by increasing the times of a water system or the strength of the water system, so that a large amount of water resources are consumed.
In order to solve the technical problems, the invention provides a method for strengthening water washing of fly ash and resource utilization of high-salinity wastewater, which comprises the following steps:
step one, washing fly ash, namely mixing the fly ash with water according to the ratio of 1: 3-5, preparing serous fluid, heating the serous fluid to 50-60 ℃, and carrying out water bath for 30-40 minutes; performing solid-liquid separation, namely performing suction filtration on the slurry subjected to water bath heating by using a suction filtration machine to obtain washing liquid and harmless fly ash;
step two, precipitating heavy metals, namely adding an inorganic flocculant into the washing liquid, wherein the mass ratio of the added inorganic flocculant to the heavy metal substances contained in the washing liquid is 1: 1.3-1.5, uniformly mixing and stirring, reacting for 20-30 minutes, adding an organic flocculant, uniformly mixing and stirring, reacting for 20-30 minutes, and performing solid-liquid separation after the solution is clarified to obtain high-salt water washing liquor and heavy metal precipitates, wherein the adding amount of the organic flocculant is 30-50 mg/l;
and step three, water washing liquid treatment, namely evaporating and crystallizing the high-salt water washing liquid through an MVR evaporator, cooling and crystallizing potassium salt, obtaining potassium salt and mixed salt waste liquid through centrifugal separation, wherein the rest of the water washing liquid is mainly potassium salt and sodium salt, the solubility of sodium chloride is small along with the change of temperature, and the solubility of sodium chloride is less than that of potassium chloride when the temperature is high, so that the high-salt water washing liquid is evaporated and crystallized through the MVR evaporator, the potassium salt can be recovered through cooling and crystallization, the main sodium chloride contained in the residual mixed salt waste liquid is used for electrolyzing the mixed salt waste liquid, and the sodium salt is obtained.
Preferably: the fly ash is washed by water, multistage water bath heating water washing is adopted,
1) mixing fly ash and water according to the proportion of 1: 4, preparing slurry by mixing the solid-liquid ratio, heating the slurry to 50-60 ℃, and carrying out water bath for 30-40 minutes;
2) carrying out suction filtration on the slurry heated by the water bath in the step 1) by using a suction filter to obtain primary cleaning water and washed fly ash; wherein, the primary cleaning water is recycled to 1) and is mixed with fly ash to prepare slurry;
3) mixing the washed fly ash obtained in the step 2) with water according to the ratio of 1: 4, preparing slurry by mixing the solid-liquid ratio, heating the slurry to 50-60 ℃, and carrying out water bath for 30-40 minutes;
4) and (3) carrying out suction filtration on the slurry heated by the water bath in the step 3) by using a suction filter to obtain a washing liquid and harmless fly ash.
Compared with the prior art, the invention has the following advantages:
1. in the stage of washing the fly ash, the water washing process of water bath heating is adopted, so that the desalting effect can be enhanced on the premise of reducing the washing times, the mass percentage concentration of chloride ions in the fly ash is reduced to below 1%, most heavy metals are washed out, the washing times can be reduced, and the water treatment cost is reduced; the washed fly ash belongs to harmless fly ash, and can be directly used as a cement raw material or other building raw materials to achieve the purposes of fly ash harmlessness and recycling;
2. in the stage of heavy metal precipitation of the washing liquid of the fly ash, an inorganic-organic flocculant combined mode is adopted, so that the total heavy metal removal rate in the washing liquid of the fly ash reaches 99 percent, the purified high-salt water washing liquid is obtained, the heavy metal removal effect is effectively enhanced, and the use amount of the flocculant is reduced;
3. in the stage of further resource utilization of the fly ash washing liquid, the MVR evaporation process is adopted to treat the purified high-salt washing liquid after heavy metal precipitation, and sodium salt and potassium salt in the washing liquid are effectively recovered.
Drawings
FIG. 1 is a flow chart of the overall process for enhanced water washing of fly ash.
FIG. 2 is a flow chart of a multi-stage water bath hot water washing process for fly ash.
Detailed Description
The method for enhancing the washing of fly ash and the utilization of high-salinity wastewater resources provided by the invention is further described below by combining the preferred embodiment and the attached drawings 1-2 in the specification.
As shown in figure 1, the invention is a method for strengthening water washing and utilizing high-salinity wastewater resources of fly ash, firstly, the fly ash is subjected to water bath heating water washing, the heating temperature is 50-60 ℃, the water bath heating water washing mode can efficiently remove a large amount of leachable anions and heavy metal ions in the fly ash, the mass percentage concentration of the chloride ions in the fly ash is reduced to below 1%, most heavy metals are washed out, washing liquid and harmless fly ash are obtained, the fly ash is stable and harmless after washing, and the possibility is provided for the subsequent recycling of the fly ash, such as serving as cement raw materials or other building raw materials; the washing liquid is subjected to removal of heavy metal precipitates in the washing liquid in a mode of combining inorganic-organic flocculants to obtain purified high-salt water washing liquid and heavy metal precipitates, wherein the removal rate of total heavy metals in the washing liquid can reach 99%; the purified high-salt water washing liquor contains about 6-15 wt% of potassium and sodium salts, potassium salt resources in China are relatively scarce, the high-salt water washing liquor is evaporated and crystallized through an MVR evaporator, potassium salt is crystallized through cooling, potassium salt and mixed salt waste liquor are obtained through centrifugal separation, the mixed salt waste liquor is electrolyzed to obtain the sodium salt, evaporation treatment is carried out on the high-salt water washing liquor, the potassium salt and the sodium salt are recovered, and the vacancy of the potassium salt in China can be relieved.
As mentioned above, the invention enhances the desalting effect by heating the water bath to wash the fly ash, washes out most heavy metals, and adopts the technology of inorganic-organic flocculation precipitator combination, makes up the incomplete defect of removing the heavy metals when the single organic or inorganic flocculation precipitator is used, greatly reduces the usage amount of the flocculation precipitator, and leads the fly ash washing liquid to be further purified for removing the heavy metals; the MVR evaporation process is adopted for the purified high-salt water washing liquid, high-pressure steam is generated in a secondary steam compression mode, the thermodynamic energy is converted, and the energy utilization rate is greatly improved. And the water temperature of the washing liquid produced in the previous water bath heating water washing stage is about 50 ℃, so that the reaction rate of subsequent flocculation precipitation can be improved, the effect of removing heavy metals by precipitation is enhanced, the high-salt water washing liquid can enter an MVR evaporation system, the temperature required to be increased before the high-salt water washing liquid enters the MVR evaporation system is reduced, the energy consumption is reduced, the operation cost is reduced, potassium salt and sodium salt are prepared by evaporating the high-salt water washing liquid of fly ash, the resource utilization of the high-salt water washing liquid is realized, and certain economic benefits are realized.
Example 1, as shown in fig. 1, it comprises the following steps:
step one, washing fly ash, namely mixing the fly ash with water according to the ratio of 1: 4, preparing slurry by mixing the solid-liquid ratio, heating the slurry to 50-60 ℃, carrying out water bath for 30-40 minutes, and carrying out suction filtration on the slurry heated by the water bath by using a suction filtration machine to obtain washing liquid and harmless fly ash;
step two, precipitating heavy metals, namely adding an inorganic flocculant into the washing liquid, wherein the mass ratio of the added inorganic flocculant to the heavy metal substances contained in the washing liquid is 1: 1.3-1.5, uniformly mixing and stirring, reacting for 20-30 minutes, adding an organic flocculant, wherein the adding amount of the organic flocculant is 30-50 mg/l, uniformly mixing and stirring, reacting for 20-30 minutes, performing flocculation precipitation on heavy metal contained in the washing solution by adopting an inorganic-organic flocculant combined mode, and performing solid-liquid separation after the solution is clarified to obtain high-salt water washing liquor and heavy metal precipitate;
and step three, water washing liquid treatment, namely evaporating and crystallizing the high-salt water washing liquid through an MVR evaporator, cooling and crystallizing potassium salt, obtaining potassium salt and mixed salt waste liquid through centrifugal separation, wherein the rest of the water washing liquid is mainly potassium salt and sodium salt, the solubility of sodium chloride is small along with the change of temperature, and the solubility of sodium chloride is less than that of potassium chloride when the temperature is high, so that the high-salt water washing liquid is evaporated and crystallized through the MVR evaporator, the potassium salt can be recovered through cooling and crystallization, the main sodium chloride contained in the residual mixed salt waste liquid is used for electrolyzing the mixed salt waste liquid, and the sodium salt is obtained.
Example 2, as shown in fig. 1 and 2, it comprises the following steps:
step one, washing the fly ash with water, heating and washing with water in a multi-stage water bath,
1) mixing fly ash and water according to the proportion of 1: 4, preparing slurry by mixing the solid-liquid ratio, heating the slurry to 50-60 ℃, and carrying out water bath for 30-40 minutes;
2) carrying out suction filtration on the slurry heated by the water bath in the step 1) by using a suction filter to obtain primary cleaning water and washed fly ash; wherein, the primary cleaning water is recycled to 1) and is mixed with fly ash to prepare slurry;
3) mixing the washed fly ash obtained in the step 2) with water according to the ratio of 1: 4, preparing slurry by mixing the solid-liquid ratio, heating the slurry to 50-60 ℃, and carrying out water bath for 30-40 minutes;
4) carrying out suction filtration on the slurry heated by the water bath in the step 3) by using a suction filter to obtain washing liquid and harmless fly ash;
step two, precipitating heavy metals, namely adding an inorganic flocculant into the washing liquid, wherein the mass ratio of the added inorganic flocculant to the heavy metal substances contained in the washing liquid is 1: 1.3-1.5, uniformly mixing and stirring, reacting for 20-30 minutes, adding an organic flocculant, wherein the adding amount of the organic flocculant is 30-50 mg/l, uniformly mixing and stirring, reacting for 20-30 minutes, performing flocculation precipitation on heavy metal contained in the washing solution by adopting an inorganic-organic flocculant combined mode, and performing solid-liquid separation after the solution is clarified to obtain high-salt water washing liquor and heavy metal precipitate;
and step three, water washing liquid treatment, namely evaporating and crystallizing the high-salt water washing liquid through an MVR evaporator, cooling and crystallizing potassium salt, obtaining potassium salt and mixed salt waste liquid through centrifugal separation, wherein the rest of the water washing liquid is mainly potassium salt and sodium salt, the solubility of sodium chloride is small along with the change of temperature, and the solubility of sodium chloride is less than that of potassium chloride when the temperature is high, so that the high-salt water washing liquid is evaporated and crystallized through the MVR evaporator, the potassium salt can be recovered through cooling and crystallization, the main sodium chloride contained in the residual mixed salt waste liquid is used for electrolyzing the mixed salt waste liquid, and the sodium salt is obtained.
Statistical differences: table 1 shows the statistical operating data of examples 1-2 and their process performance.
| Item | Chloride ion removal Rate (%) | Total weight metal removal (%) |
| Example 1 | 99.2 | 99.1 |
| Example 2 | 99.2 | 99.4 |
As can be seen from Table 1, the method for enhancing water washing of fly ash and resource utilization of high-salt wastewater provided by the invention has higher desalination efficiency, can efficiently remove a large amount of leachable anions and heavy metal ions in the fly ash in a water bath heating water washing mode, reduce the mass percentage concentration of chloride ions in the fly ash to below 1%, and wash most of heavy metals, and adopts a mode of combining inorganic-organic flocculants to precipitate and remove the heavy metals in the washing liquid, the removal rate of the total heavy metals in the washing liquid can reach 99%, and the high-salt water washing liquid containing about 6-15 wt% of potassium and sodium salts can be recovered and extracted in an MVR evaporation mode, so that nearly full recycling of the fly ash washing liquid is achieved.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and all simple modifications, changes and equivalent process changes made to the above embodiment according to the technical spirit of the present invention still fall within the protection scope of the technical solution of the present invention.
Claims (2)
1. A method for strengthening water washing of fly ash and resource utilization of high-salinity wastewater is characterized by comprising the following steps:
step one, washing fly ash, namely mixing the fly ash with water according to the ratio of 1: 3-5, preparing serous fluid, heating the serous fluid to 50-60 ℃, and carrying out water bath for 30-40 minutes; performing solid-liquid separation, namely performing suction filtration on the slurry subjected to water bath heating by using a suction filtration machine to obtain washing liquid and harmless fly ash;
step two, precipitating heavy metals, namely adding an inorganic flocculant into the washing liquid, wherein the mass ratio of the added inorganic flocculant to the heavy metal substances contained in the washing liquid is 1: 1.3-1.5, uniformly mixing and stirring, reacting for 20-30 minutes, adding an organic flocculant, uniformly mixing and stirring, reacting for 20-30 minutes, and performing solid-liquid separation after the solution is clarified to obtain high-salt water washing liquor and heavy metal precipitates, wherein the adding amount of the organic flocculant is 30-50 mg/l;
and step three, water washing liquid treatment, namely evaporating and crystallizing the high-salt water washing liquid through an MVR evaporator, cooling and crystallizing potassium salt, obtaining potassium salt and mixed salt waste liquid through centrifugal separation, and electrolyzing the mixed salt waste liquid to obtain sodium salt.
2. The method of claim 1, wherein the method comprises the steps of: the fly ash is washed by water, multistage water bath heating water washing is adopted,
1) mixing fly ash and water according to the proportion of 1: 4, preparing slurry by mixing the solid-liquid ratio, heating the slurry to 50-60 ℃, and carrying out water bath for 30-40 minutes;
2) carrying out suction filtration on the slurry heated by the water bath in the step 1) by using a suction filter to obtain primary cleaning water and washed fly ash; wherein, the primary cleaning water is recycled to 1) and is mixed with fly ash to prepare slurry;
3) mixing the washed fly ash obtained in the step 2) with water according to the ratio of 1: 4, preparing slurry by mixing the solid-liquid ratio, heating the slurry to 50-60 ℃, and carrying out water bath for 30-40 minutes;
4) and (3) carrying out suction filtration on the slurry heated by the water bath in the step 3) by using a suction filter to obtain a washing liquid and harmless fly ash.
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