CN111747438B - pH regulation and control multistep stabilization modification method for dry/semi-dry desulfurized fly ash - Google Patents
pH regulation and control multistep stabilization modification method for dry/semi-dry desulfurized fly ash Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F11/00—Compounds of calcium, strontium, or barium
- C01F11/46—Sulfates
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
- B01F25/20—Jet mixers, i.e. mixers using high-speed fluid streams
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
- B01F35/20—Measuring; Control or regulation
- B01F35/21—Measuring
- B01F35/2132—Concentration, pH, pOH, p(ION) or oxygen-demand
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J19/0006—Controlling or regulating processes
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F5/00—Compounds of magnesium
- C01F5/14—Magnesium hydroxide
- C01F5/22—Magnesium hydroxide from magnesium compounds with alkali hydroxides or alkaline- earth oxides or hydroxides
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
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- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Inorganic Chemistry (AREA)
- Treating Waste Gases (AREA)
- Processing Of Solid Wastes (AREA)
Abstract
The invention relates to a pH regulation and control multistep stabilization modification method of dry/semi-dry desulfurized fly ash, which comprises the following steps: raw material analysis and test (1) and acid liquor preparation (2); (3) acidifying the raw material; (4) forced oxidation; (5) regulating and controlling the pH value; (6) multi-step circulation; (7) recovering the product; (8) recycling waste liquor and recovering Mg; (9) finishing the modification; the conventional one-step oxidation process is decomposed into multiple steps, and the solid-liquid ratio and the slurry pH of each step are accurately controlled to avoid SO 2 While releasing, the reaction rate of the forced oxidation process is obviously improved, and the instability and the high alkalinity brought by SO of the dry method/semidry method desulfurized fly ash are finally overcome 2 The problems of secondary pollution and slow oxidation rate are solved, and clean and efficient modification is creatively realized; meanwhile, the resource utilization of the dry/semi-dry desulfurized fly ash and the waste sulfuric acid is realized, so that the aims of treating waste by waste and realizing synergistic circulation are fulfilled, and better economic and environmental benefits are obtained.
Description
Technical Field
The invention relates to stabilization modification and resource utilization of dry/semi-dry desulfurized fly ash, in particular to a multi-step pH regulation stabilization modification method of dry/semi-dry desulfurized fly ash, belonging to the technical field of resources and environment.
Background
In recent years, due to the high importance of our country on the ecological environment protection, and the high importance of our country on SO 2 The emission requirements are becoming stricter, and the flue gas desulfurization process is widely popularized and applied in the industries of coal-fired power plants, steel sintering, industrial boilers, petrochemical industry and the like, wherein dry/semi-dry processes represented by CFB, LIFAC, NID, SDA and CDSI are adoptedThe method desulfurization process has the advantages of small occupied area, low investment, low operating cost, low energy consumption, no sewage and waste acid discharge and the like, and becomes a trend of future development of the flue gas desulfurization technology.
The dry/semi-dry desulfurizing process features that powdered or granular calcium-base absorbent is used to eliminate SO from fume 2 The desulfurization product is dry powder and mainly comprises CaSO 3 ·1/2H 2 O、CaCO 3 、CaSO 4 ·2H 2 O and a small amount of unreacted Ca (OH) 2 And the like. Compared with wet desulphurization process, the desulphurization ash produced by dry/semi-dry desulphurization process has much more complex components, and has the characteristics of high sulfur, high calcium and high alkalinity, especially CaSO 3 The proportion of (A) is high, and the component with poor chemical stability causes the dry/semi-dry desulfurized fly ash to show unusual physicochemical properties. Because the research on the properties, the reaction characteristics and the action mechanism of the solid wastes is not systematic and deep, people have more attentions on the comprehensive utilization of the solid wastes at present, and an effective utilization way is not formed yet, so that the dry/semi-dry desulfurization ash is accumulated in a large amount or is simply buried, a large amount of valuable land resources are occupied, the enterprise burden is increased, and the further popularization and application of the dry/semi-dry desulfurization process are restricted. In addition, since CaSO 3 Is unstable and is easy to cause SO after long-term stacking 2 Causing potential threat to the environment; meanwhile, the dry method/semi-dry method desulfurized ash has small particle size and light weight, and can fly everywhere to pollute air once blown by wind.
For the comprehensive utilization of the dry method/semidry method desulfurized fly ash, the related work at home and abroad does not form a complete system at present, the obtained achievements belong to research properties, no technology for large-scale industrial application is formed, and the reason is researched, and the four aspects are as follows:
(1) The chemical composition of the desulphurisation ash is quite complex. The phase compositions of the general dry/semi-dry desulfurized fly ash comprise CaSO 4 、CaSO 3 、CaCO 3 、Ca(OH) 2 、CaO、MgCO 3 A plurality of components, which make the whole body show complex and diverse chemical propertiesTherefore, the comprehensive utilization is more limited and the utilization difficulty is higher.
(2) The fluctuation of the content of each component of the desulfurized fly ash is large. Due to the differences of the operation, operation and management levels of different enterprises, the differences of different raw material types and proportioning schemes, the differences of desulfurization efficiencies of different desulfurization processes and the differences of components of different batches of coal, the content of each component of desulfurization ash generated by different desulfurization equipment and different periods of time of the same equipment can fluctuate greatly. Such fluctuations bring about frequent changes in the overall chemistry, which makes its comprehensive utilization difficult.
(3) The chemical nature of the various components in the desulfurized fly ash is unstable. CaSO in desulfurized fly ash 3 、Ca(OH) 2 And CaO is chemically unstable and changes with environmental and time changes. CaSO 3 Easily decomposed in acid environment or under high temperature condition of neutral or reducing atmosphere to make SO 2 Is released again to cause secondary pollution to the environment, and simultaneously CaSO 3 Will be oxidized into CaSO in the air 4 Resulting in instability of the properties of the desulfurized fly ash material over long periods of use. CaO readily absorbs water to form Ca (OH) 2 Causing a volume differential expansion, ca (OH) 2 Reabsorbing CO from air 2 To produce CaCO 3 . These instabilities pose a major obstacle to the comprehensive utilization of the desulfurized fly ash.
(4) CaSO in desulfurized fly ash 3 Has a high content of and CaSO 3 The action effect and mechanism of (A) are not clear. CaSO in dry/semi-dry desulfurized fly ash 3 The content of (A) can be up to more than 50%, and CaSO 3 The influence on the overall mechanical properties and stability of the material is yet to be further researched and confirmed. For example, when desulfurized fly ash is used as a cement retarder, caSO 3 The retarding effect and the influence on the mechanical property of the cement are still greatly controversial.
In conclusion, under the new background that China vigorously promotes the construction of 'waste-free cities' and 'waste-free society', the dry method/semidry method desulfurized fly ash is scientifically treated and finely utilized to realize harmlessness and deep recycling, so that the method not only solves the technical problems to be solved urgently in the industries of coal-fired power plants, steel sintering, industrial boilers, petrifaction and the like in China, but also promotes ecological civilization construction in China, promotes high-quality development, and realizes the inevitable requirements on comprehensive conservation and cyclic utilization of resources.
Based on the basic chemical principles of acid-base neutralization and redox, the dry/semi-dry desulfurization ash is subjected to forced oxidation modification in a sulfuric acid environment, so that the problems in the four aspects of limiting large-scale comprehensive utilization of the solid waste can be solved at one stroke: caCO in the desulfurized fly ash under the action of acid-base neutralization reaction 3 、Ca(OH) 2 And the basic components such as CaO and the like are all rapidly converted into CaSO 4 (ii) a And CaSO with poor stability under the action of oxidation reaction 3 Will also be converted into CaSO 4 . Thus, the original dry/semi-dry desulfurized fly ash with complex and various components and unstable content and chemical properties of various components is converted into stable CaSO 4 Is a solid waste with chemical properties similar to those of wet desulphurization gypsum as a main component. Because the technical problems of each link in the comprehensive utilization of the wet desulphurization gypsum are basically solved, the modified dry/semi-dry desulphurization ash can be comprehensively utilized on a large scale according to various technical routes of the wet desulphurization gypsum, thereby thoroughly solving the increasingly urgent treatment problem of the large solid wastes. Meanwhile, the resource utilization of the waste sulfuric acid is realized.
However, due to SO 3 2- Will react with excessive H + Combine to form pollutant SO 2 Therefore, the pH of the reaction solution cannot be too low; meanwhile, the pH value of the solution is rapidly increased in the dissolving process due to strong alkalinity of the desulfurized fly ash, and CaSO 3 The solubility of (a) is very low and further decreases with the increase of the pH value, so that the oxidation rate is greatly reduced, and therefore, the solid-to-liquid ratio in the dissolving process, namely the pH value of the solution, cannot be too high. In conclusion, the high-efficiency oxidation of the dry/semi-dry desulfurized ash is realized in a one-step method and a conventional slurry manner, and the SO-free desulfurization is realized 2 Release is very difficult and innovative stabilization modifications to adapt to the characteristics of the desulfurized fly ash need to be developed.
Disclosure of Invention
In order to make up for the defects of the prior art, the invention aims to provide a pH regulation and multi-step stabilization modification method of the desulfurization ash of the dry/semi-dry method, which decomposes the conventional one-step oxidation process into multiple steps, overcomes the problem of slow oxidation rate caused by high alkalinity of the desulfurization ash of the dry/semi-dry method, and avoids the problem of low oxidation rate caused by high alkalinity of the desulfurization ash of the dry/semi-dry method 2 And releasing, and finally realizing the resource utilization of the dry/semi-dry desulfurized fly ash and the waste sulfuric acid, thereby achieving the purposes of treating waste by waste and realizing synergistic circulation and obtaining better economic and environmental benefits.
The invention aims to realize the purpose through the following technical scheme, and discloses a pH regulation and control multistep stabilization modification method of dry/semi-dry desulfurized fly ash, which has the technical key points that: the method comprises the following steps:
(1) Analysis of raw materials test
Analyzing and testing the components of the original dry/semi-dry desulfurized fly ash to determine CaSO in the desulfurized fly ash 3 And the content of various strong basic compounds;
(2) Preparation of acid liquor
Preparing the waste sulfuric acid stock solution with the mass fraction of 2-98 percent into H with the pH value of 2.2-4.0 2 SO 4 A solution, placed in an oxidation reactor;
(3) Acidification of the feedstock
Gradually toward H in said step (2) 2 SO 4 Adding the dry-process/semi-dry-process desulfurized fly ash obtained in the step (1) into the solution, continuously stirring to obtain a mixed solution, simultaneously monitoring the change of the pH value of the mixed solution in real time, and stopping adding the desulfurized fly ash when the pH value of the mixed solution rises to a certain value within the range of 3.3-5.6 and is kept stable;
(4) Forced oxidation
Using air as an oxidant, and carrying out jet aeration on the mixed liquor obtained in the step (3) by adopting a jet aerator, wherein the jet aerator comprises 1-16 aeration heads, the working air pressure is less than or equal to 10m of water column, the working water pressure is less than or equal to 30m of water column, and the working air volume and the water volume of each aeration head are respectively 20-80 Nm 3 H and 8-18 m 3 H, oxygen transfer efficiency of 9 to 18g O 2 /Nm 3 ·m；
(5) Control of pH
After forced oxidation, when the pH value of the mixed solution is kept stable, the waste sulfuric acid stock solution in the step (2) is gradually added into the solution, so that the pH value of the solution is reduced to a certain value in the range of 2.2-4.0 again and is kept stable;
(6) Multiple step cycle
Continuously repeating the steps (3) to (5), wherein the mixed solution in the step (5) gradually contains solid-phase CaSO 4 Separating out to obtain slurry with solid content of 5-25%;
(7) Recovery of products
Discharging the slurry part obtained in the step (6), and performing solid-liquid separation and dehydration treatment to obtain a stabilized modified gypsum product and residual waste liquid;
(8) Waste liquor circulation and Mg recovery
Returning the residual waste liquid of the step (7) to the oxidation reactor of the step (2) for recycling, or adding Ca (OH) with the purity of more than 90 percent 2 To prepare Mg (OH) 2 The product is used for recycling Mg element in the desulfurized ash of the dry method/semi-dry method in the first step;
the Ca (OH) 2 The adding amount is calculated according to the Mg content of the original desulfurized fly ash in the step (1) and the cumulative adding amount of the desulfurized fly ash in the step (3);
the calculation method comprises the following steps: ca (OH) 2 Addition = original desulfurized ash Mg content × desulfurized ash cumulative addition x (100% -original desulfurized ash moisture content)/24 × 74/(100% -Ca (OH) 2 Water content of)/Ca (OH) 2 The purity of (a);
and (9): completion of modification
And (5) repeating the steps (3) to (8), and finally completing the multi-step stabilization modification of the whole dry/semi-dry desulfurization ash.
Further, the oxidation reactor is provided with an exhaust port, a liquid level, a temperature, a pH value and SO 2 Provided is an online monitoring device.
Further, in the step (3), feeding the desulfurized ash through a metering screw feeder; the agitation is achieved by a mechanical stirrer or a jet aerator.
Further, in the step (5), the waste sulfuric acid is fed by a metering acid liquid pump.
Further, in the step (7), the solid-liquid separation is realized by a hydrocyclone; the dewatering is achieved by a vacuum belt dewaterer or a belt filter press.
Further, in the step (8), the Ca (OH) 2 And adding the mixture by a metering screw feeder.
Compared with the prior art, the invention has the following beneficial effects:
(1) The pH value of the acidified slurry in the whole stabilizing and modifying process is controlled to be between 2.2 and 5.6 all the time based on the optimal solid-liquid ratio, so that CaSO in the desulfurized fly ash can be avoided 3 Decompose to release SO 2 And can ensure enough CaSO 3 Is in a liquid phase reaction system, thereby obviously improving the reaction rate of the whole modification process.
(2) The conventional one-step oxidation process is decomposed into multiple steps, and the problem of slow oxidation rate caused by high alkalinity of the desulfurization ash by the dry method/semi-dry method is solved by accurately controlling the solid-liquid ratio and the pH value of the slurry in each step of oxidation process, so that the high-efficiency oxidation of the high-alkalinity desulfurization ash is creatively realized.
(3) The jet aeration technology has the advantages of strong mixing and stirring effects, high oxygenation capacity, high oxygen utilization rate, high oxygen power transfer efficiency, simple structure, no moving parts, reliable work, flexible operation, convenient adjustment, difficult blockage, easy maintenance and management, low operating cost and the like, and can obviously improve the reaction rate of the forced oxidation process.
(4) The method can simultaneously realize the resource utilization of the dry method/semi-dry method desulfurized fly ash and the waste sulfuric acid, thereby achieving the purposes of treating waste by waste and realizing synergistic circulation and obtaining better economic and environmental benefits.
(5) Can realize high-value utilization of Mg element in the dry method/semi-dry method desulfurized fly ash, and further improves economic and environmental benefits.
Description of the drawings:
FIG. 1 is a logic flow chart of the pH regulation multi-step stabilization modification method of the dry/semi-dry desulfurization ash.
In FIG. 1, 1 is step (1), 2 is step (2), 3 is step (3), 4 is step (4), 5 is step (5), 6 is step (6), 7 is step (7), 8 is step (8), and 9 is step (9).
FIG. 2 shows the semidry desulfurized fly ash and 80% concentrated H in a certain iron and steel plant 2 SO 4 The reagent is used as a raw material, acidification and forced oxidation laboratory tests are carried out according to the pH regulation and control multistep stabilization modification method, and finally when the solid content of the slurry reaches 10%, the slurry comes from CaSO 3 S balance of (1).
Detailed Description
The invention is further described with reference to the following figures and specific examples.
Example 1
A pH regulation and control multistep stabilization modification method for desulfurization ash by a dry method/semi-dry method comprises the following steps:
(1) Analysis of raw materials test
Analyzing and testing the components of the original dry/semi-dry desulfurized fly ash to determine CaSO in the desulfurized fly ash 3 And the contents of various strongly basic compounds; the solid-liquid ratio of the desulfurized fly ash and the waste sulfuric acid in the oxidation process is estimated; to clarify CaSO therein 3 And the content of various strong alkaline compounds, which is used for estimating the solid-liquid ratio between the desulfurized fly ash and the waste sulfuric acid in the oxidation process and providing reference for the subsequent pH regulation process;
(2) Preparation of acid liquor
Preparing the waste sulfuric acid stock solution with the mass fraction of 2-98 percent into H with the pH value of 2.2-4.0 2 SO 4 A solution, placed in an oxidation reactor;
2% -98% is the concentration of original waste sulfuric acid in the step, its acidity is very big, pH value is far lower than 2.2, the step is to dilute the original waste sulfuric acid with water, make its pH value stabilize in a certain value between 2.2-4.0, and place it in oxidation reactor.
(3) Acidification of the feedstock
Gradually moving to H in the step (2) 2 SO 4 Adding the dry method/semi-dry method desulfurized ash obtained in the step (1) into the solution, continuously stirring to obtain a mixed solution, and simultaneously adding the mixed solution into the solutionMonitoring the change of the pH value of the mixed solution in real time, and stopping adding the desulfurized ash when the pH value of the mixed solution rises to a certain value within the range of 3.3-5.6 and is kept stable;
(4) Forced oxidation
Using air as an oxidant, and carrying out jet aeration on the mixed liquor obtained in the step (3) by adopting a jet aerator, wherein the jet aerator comprises 1-16 aeration heads, the working air pressure is less than or equal to 10m of water column, the working water pressure is less than or equal to 30m of water column, and the working air volume and the water volume of each aeration head are respectively 20-80 Nm 3 H and 8-18 m 3 H, oxygen transfer efficiency of 9 to 18g O 2 /Nm 3 M; HSO in solution at this time 3 - Will be oxidized to SO 4 2- To release H + The pH value of the mixed solution is reduced by 0.4 to 1.3 by the jet aeration;
(5) Control of pH
After forced oxidation, when the pH value of the mixed solution is kept stable, the waste sulfuric acid stock solution in the step (2) is gradually added into the solution, so that the pH value of the solution is reduced to a certain value in the range of 2.2-4.0 again and is kept stable; the term "stable" means that the pH value is finally maintained at any value point of 3.3-5.6 or 2.2-4.0 after rising or falling and is not changed any more, and then the corresponding treatment step can be carried out;
(6) Multiple step cycle
Continuously repeating the steps (3) to (5), wherein solid-phase CaSO gradually exists in the mixed solution in the step (5) 4 Separating out to obtain slurry with solid content of 5-25%;
(7) Recycled product
Discharging the slurry part obtained in the step (6), and performing solid-liquid separation and dehydration treatment to obtain a stabilized modified gypsum product and residual waste liquid;
(8) Waste liquor circulation and Mg recovery
Returning the residual waste liquid of the step (7) to the oxidation reactor of the step (2) for recycling, or adding Ca (OH) with the purity of more than 90 percent 2 To prepare Mg (OH) 2 The product is used for recycling Mg element in the desulfurized ash of the dry method/semi-dry method in the first step,
the Ca (OH) 2 The adding amount is calculated according to the Mg content of the original desulfurized fly ash in the step (1) and the cumulative adding amount of the desulfurized fly ash in the step (3);
the calculation method comprises the following steps: ca (OH) 2 Addition = original desulfurized ash Mg content × desulfurized ash cumulative addition x (100% -original desulfurized ash moisture content)/24 × 74/(100% -Ca (OH) 2 Water content of)/Ca (OH) 2 The purity of (2);
and (9): completion of modification
And (5) repeating the steps (3) to (8), and finally completing the multi-step stabilization modification of the whole dry/semi-dry desulfurization ash.
Example 2 Multi-step stabilizing modification of semi-dry desulfurized fly ash from certain iron and steel works by pH control
The pH regulation and control multi-step stabilization modification method of the dry/semi-dry desulfurized fly ash comprises the following 9 steps:
step (1): and (4) analyzing and testing raw materials. Analyzing and testing the components of the dry/semi-dry desulfurized fly ash to determine CaSO in the desulfurized fly ash 3 And the contents of various strongly basic compounds, the results are shown in Table 1;
TABLE 1 original composition of semi-dry desulfurized fly ash (dry basis)
| Cl - | SO 3 | CaCO 3 | Dihydrate CaSO 4 | CaSO 4 | MgCO 3 | CaSO 3 | Ca(OH) 2 | Other impurities |
| 1.02％ | 1.57％ | 32.77％ | 0.36％ | 3.32％ | 8.86％ | 39.65％ | 6.60％ | 5.85％ |
Step (2): and (4) preparing acid liquor. Preparing the waste sulfuric acid with the mass fraction of 80 percent into H with a certain volume and the pH value of 2.7 2 SO 4 A solution, placed in an oxidation reactor;
and (3): and (4) acidifying the raw material. Step (2) of gradual process H 2 SO 4 Adding the dry method/semi-dry method desulfurized fly ash obtained in the step (1) into the solution, continuously stirring, simultaneously monitoring the change of the pH value of the solution in real time, and stopping adding the desulfurized fly ash when the pH value is raised to 5.5 and kept stable;
and (4): and (4) forced oxidation. Carrying out jet aeration on the solution obtained in the step (3) by taking air as an oxidant, wherein the jet aerator adopts 4 aeration heads, the working air pressure is 5m of water column, the working water pressure is 12m of water column, and the working air volume and the water volume of each aeration head are respectively 30Nm 3 H and 10m 3 H, oxygen transfer efficiency of 11g O 2 /Nm 3 M, HSO in solution at this time 3 - Is oxidized into SO 4 2- To release H + Thereby reducing the pH value of the solution by 1.3;
and (5): the pH was adjusted. When the pH value of the solution in the step (5) is kept stable at 4.2, the waste sulfuric acid in the step (2) is gradually added into the solution, so that the pH value of the solution is reduced to 2.7 again and is kept stable, and the ratio of the addition amount of the waste sulfuric acid to the addition amount of the desulfurization ash in the step (3) is 0.4m 3 Waste sulfuric acid: 1 ton of desulfurized fly ash;
and (6): and (4) circulating in multiple steps. Continuously repeating the steps (3) to (5) to ensure that solid CaSO gradually exists in the solution in the step (5) 4 Precipitating and finally forming slurry with the solid content of 10%;
and (7): and (5) recovering the product. When the solid content of the slurry in the step (6) reaches 10%, discharging a part of the slurry, and carrying out solid-liquid separation, dehydration and other treatments to obtain a stabilized and modified gypsum product;
and (8): and recycling the waste liquid and recovering Mg. For the discharged slurry in the step (7), the residual waste liquid after the gypsum product is recovered can be returned to the oxidation reactor in the step (2) for recycling, and Ca (OH) with the purity of more than 90 percent can also be added 2 To prepare Mg (OH) 2 A product for recycling Mg element, particularly Ca (OH), in the dry/semi-dry desulfurized fly ash obtained in the step (1) 2 The adding amount is calculated according to the Mg content of the original desulfurized fly ash in the step (1) and the cumulative adding amount of the desulfurized fly ash in the step (3), and the calculating method comprises the following steps: ca (OH) 2 Addition = original desulfurized fly ash Mg content X desulfurized fly ash cumulative addition X (100% -original desulfurized fly ash water content)/24X 74/(100% -Ca (OH) 2 Water content of)/Ca (OH) 2 The purity of (2);
step (9); and (5) finishing the modification. And (5) continuously repeating the steps (3) to (8) for the residual slurry in the oxidation reactor, and finally completing the multi-step stabilization modification of the whole dry/semi-dry desulfurization ash.
In the step (2), the oxidation reactor is provided with an exhaust port, a liquid level, a temperature, a pH value and SO 2 Provided is an online monitoring device.
And (4) in the step (3), feeding the desulfurized ash through a metering screw feeder.
In the step (3), the stirring is realized by a mechanical stirrer or a jet aerator.
In the step (5), the waste sulfuric acid is added by a metering acid liquid pump.
In the step (7), the solid-liquid separation is realized by a hydrocyclone.
In the step (7), the dehydration is realized by a vacuum belt dehydrator or a belt filter press.
In step (8), ca (OH) 2 And adding the mixture by a metering screw feeder.
The pH regulation and control multistep stabilization modification method is adopted for acidification and forced oxidation tests, and when the solid content of the slurry reaches 10 percent, the slurry comes from CaSO 3 S-balance of (a) is shown in fig. 2. Table 2 shows the ingredients of the resulting modified product. It can be seen that CaSO is the most important component in the original semi-dry desulfurized fly ash 3 And CaCO 3 39.65% and 32.77%, respectively, and a certain amount of MgCO 3 And Ca (OH) 2 Equal high alkalinity component, caSO 4 The content of (A) is very low. By the pH regulation and control multistep stabilization modification method, almost all CaSO in original semi-dry desulfurization ash 3 、CaCO 3 And Ca (OH) 2 Are all converted into dihydrate CaSO 4 Modified product of dihydrate CaSO 4 The content of the modified starch reaches 93.97 percent, and a good modification effect is obtained.
TABLE 2 ingredients of modified products (dry basis)
| Cl - | SO 3 | CaCO 3 | Dihydrate CaSO 4 | CaSO 4 | MgCO 3 | CaSO 3 | Ca(OH) 2 | Other impurities |
| 0.09％ | 0.08％ | 0.00％ | 93.97％ | 0.39％ | 0.00％ | 0.21％ | 0.00％ | 5.26％ |
The embodiments described above are intended to facilitate a person of ordinary skill in the art in a comprehensive understanding and making effective use of the invention. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above-mentioned embodiments, and modifications made by those skilled in the art according to the teachings of the present invention without departing from the scope of the present invention should be within the protection scope of the present invention.
The principle of the invention is as follows:
(1) And (2) controlling the pH value of the acidified slurry in the whole stabilizing modification process to be between 2.2 and 5.6 all the time by taking the optimal solid-liquid ratio as a basis, wherein the optimal solid-liquid ratio is embodied by controlling the pH value of the solution to be within a certain range all the time when each step of oxidation is carried out: firstly adding desulfurized ash to stabilize the pH value of the solution at a certain value within the range of 3.3-5.6, wherein a solid is added; and adding waste sulfuric acid to stabilize the pH value of the solution within a range of 2.2-4.0, wherein one waste sulfuric acid is added. The so-called optimal solid-to-liquid ratio is the ratio between these two quantities.
(2) Increase oxidation rate and avoid SO 2 Releasing
The conventional one-step oxidation process is decomposed into multiple steps, the solid-liquid ratio and the slurry pH value of each step of oxidation process are accurately controlled, and meanwhile, the jet aeration technology adopted has strong mixing and stirring effects and higher oxygenation capacity, oxygen utilization rate and oxygen power transfer efficiency, SO that SO is avoided 2 And when the high-alkalinity desulfurization ash is released, the high-efficiency oxidation of the high-alkalinity desulfurization ash is creatively realized.
Claims (6)
1. A pH regulation and control multistep stabilization modification method of dry method/semidry method desulfurized fly ash is characterized in that: the method comprises the following steps:
(1) Analysis of raw materials test
Analyzing and testing the components of the original dry/semi-dry desulfurized fly ash to determine CaSO in the desulfurized fly ash 3 And the content of various strong basic compounds;
(2) Preparation of acid liquor
Preparing the waste sulfuric acid stock solution with the mass fraction of 2-98% into H with the pH value of 2.2-4.0 2 SO 4 A solution, placed in an oxidation reactor;
(3) Acidification of the feedstock
Gradually moving to H in the step (2) 2 SO 4 Adding the dry/semi-dry desulphurization ash obtained in the step (1) into the solution, continuously stirring to obtain a mixed solution, simultaneously monitoring the change of the pH value of the mixed solution in real time, and stopping adding the desulphurization ash when the pH value of the mixed solution rises to 3.3-5.6;
(4) Forced oxidation
Carrying out jet aeration on the mixed liquid obtained in the step (3) by using air as an oxidant and adopting a jet aerator, wherein the jet aerator comprises 1 to 16 aeration heads, the working air pressure is less than or equal to 10m of water column, the working water pressure is less than or equal to 30m of water column, and the working air volume and the water volume of each aeration head are respectively 20 to 80Nm 3 H and 8 to 18m 3 H, oxygen transfer efficiency of 9 to 18g O 2 /Nm 3 ·m；
(5) Control of pH
After forced oxidation, gradually adding the waste sulfuric acid stock solution in the step (2) into the solution when the pH value of the mixed solution is kept stable, and reducing the pH value of the solution to 2.2-4.0 again;
(6) Multiple step cycle
Continuously repeating the steps (3) to (5), wherein solid-phase CaSO gradually exists in the mixed solution in the step (5) 4 Separating out to obtain slurry with the solid content of 5-25%;
(7) Recycled product
Discharging the slurry part obtained in the step (6), and performing solid-liquid separation and dehydration treatment to obtain a stabilized modified gypsum product and residual waste liquid;
(8) Waste liquor circulation and Mg recovery
Returning the residual waste liquid of the step (7) to the oxidation reactor of the step (2) for recycling, or adding Ca (OH) with the purity of more than 90 percent 2 To prepare Mg (OH) 2 A product used for recycling Mg element in the dry/semi-dry desulphurization ash in the step (1),
the Ca (OH) 2 The adding amount is calculated according to the Mg content of the original desulfurized fly ash in the step (1) and the cumulative adding amount of the desulfurized fly ash in the step (3);
the calculation method comprises the following steps: ca (OH) 2 Addition = original desulfurized ash Mg content × desulfurized ash cumulative addition x (100% -original desulfurized ash moisture content)/24 × 74/(100% -Ca (OH) 2 Water content of)/Ca (OH) 2 The purity of (a);
and (9): completion of modification
And (5) repeating the steps (3) to (8), and finally completing the multi-step stabilization modification of the whole dry/semi-dry desulfurization ash.
2. The method for multi-step stabilization and modification of desulfurization ash by pH regulation of dry/semi-dry process as claimed in claim 1, which is characterized in that: the oxidation reactor is provided with an exhaust port, a liquid level, a temperature, a pH value and an SO value 2 Provided is an online monitoring device.
3. The method for multi-step stabilization and modification of desulfurization ash by pH regulation of dry/semi-dry process as claimed in claim 1, which is characterized in that: in the step (3), feeding the desulfurized ash through a metering screw feeder; the agitation is achieved by a mechanical stirrer or a jet aerator.
4. The method for the pH-regulated multi-step stabilization and modification of the dry/semi-dry desulfurized fly ash according to claim 1, which is characterized in that: in the step (5), the waste sulfuric acid is added through a metering acid liquid pump.
5. The method for multi-step stabilization and modification of desulfurization ash by pH regulation of dry/semi-dry process as claimed in claim 1, which is characterized in that: in the step (7), the solid-liquid separation is realized by a hydrocyclone; the dewatering is achieved by a vacuum belt dewaterer or a belt filter press.
6. The method for the pH-regulated multi-step stabilization and modification of the dry/semi-dry desulfurized fly ash according to claim 1, which is characterized in that: in the step (8), the Ca (OH) 2 And adding the mixture by a metering screw feeder.
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102000481A (en) * | 2009-08-31 | 2011-04-06 | 宝山钢铁股份有限公司 | Method for treating desulfurization ash |
| CN102225781A (en) * | 2011-04-01 | 2011-10-26 | 洛阳理工学院 | Preparation method of cement delayed coagulant |
| CN103232054A (en) * | 2013-05-08 | 2013-08-07 | 武汉钢铁(集团)公司 | Method for oxidizing CaSO3 in desulfurized fly ash in alkaline condition |
| CN109455752A (en) * | 2018-11-29 | 2019-03-12 | 黄冈师范学院 | A kind of desulfurization ash prepares the method and device of calcium sulfate |
| CN110182838A (en) * | 2019-06-25 | 2019-08-30 | 湘潭大学 | A kind of modified technique system and method for flue gas desulfurization ash |
| CN110304647A (en) * | 2019-07-31 | 2019-10-08 | 南京中电环保科技有限公司 | A kind of dry-process desulfurized ash of utilization society spent acid prepares desulfurized gypsum method and system |
| CN110436506A (en) * | 2019-08-14 | 2019-11-12 | 东北大学 | Using industrial waste sulfuric acid to the method for semi-dry desulphurization ash oxidation processes |
| CN210206434U (en) * | 2019-05-23 | 2020-03-31 | 新疆天富环保科技有限公司 | Wet desulphurization device for resource utilization of semidry desulphurization ash |
-
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Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102000481A (en) * | 2009-08-31 | 2011-04-06 | 宝山钢铁股份有限公司 | Method for treating desulfurization ash |
| CN102225781A (en) * | 2011-04-01 | 2011-10-26 | 洛阳理工学院 | Preparation method of cement delayed coagulant |
| CN103232054A (en) * | 2013-05-08 | 2013-08-07 | 武汉钢铁(集团)公司 | Method for oxidizing CaSO3 in desulfurized fly ash in alkaline condition |
| CN109455752A (en) * | 2018-11-29 | 2019-03-12 | 黄冈师范学院 | A kind of desulfurization ash prepares the method and device of calcium sulfate |
| CN210206434U (en) * | 2019-05-23 | 2020-03-31 | 新疆天富环保科技有限公司 | Wet desulphurization device for resource utilization of semidry desulphurization ash |
| CN110182838A (en) * | 2019-06-25 | 2019-08-30 | 湘潭大学 | A kind of modified technique system and method for flue gas desulfurization ash |
| CN110304647A (en) * | 2019-07-31 | 2019-10-08 | 南京中电环保科技有限公司 | A kind of dry-process desulfurized ash of utilization society spent acid prepares desulfurized gypsum method and system |
| CN110436506A (en) * | 2019-08-14 | 2019-11-12 | 东北大学 | Using industrial waste sulfuric acid to the method for semi-dry desulphurization ash oxidation processes |
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