CN110642548B - Method for treating dry-process desulfurized fly ash - Google Patents
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
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- B01D53/34—Chemical or biological purification of waste gases
- B01D53/46—Removing components of defined structure
- B01D53/48—Sulfur compounds
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Abstract
The invention provides a method for treating dry desulfurization ash, which comprises the following steps: a) the oxidized hot air and the dry-method desulfurized fly ash to be treated enter an oxidation device to be contacted with each other, and oxidized high-temperature desulfurized fly ash and oxidized hot air are respectively obtained; the oxygen content of the oxidation hot air is 15-22%, and the temperature is 400-900 ℃; b) cooling the oxidized high-temperature desulfurized fly ash obtained in the step a) to obtain a treated product. Compared with the prior art, the treatment method provided by the invention has the advantages that the oxidized hot air is directly and fully contacted and oxidized with the dry-method desulfurized ash, the heat transfer efficiency and the mass transfer efficiency are high, the oxidation time is shortened, the temperature range is wider, the requirement on the oxygen content is wider, the oxidized hot air is sent to a hot air recycling device for continuous utilization, the adaptability, the operability and the economy are better, and the treated product is suitable for being further applied as a cement retarder.
Description
Technical Field
The invention relates to the technical field of dry desulfurization ash resource utilization, in particular to a method for treating dry desulfurization ash.
Background
At present, the wet method, the semi-dry method and the dry method are mainly adopted for flue gas desulfurization in China, and the SO is reduced along with the increasingly strict requirements on air quality in China3And a chimney white dragon and desulfurization waste water put forward treatment requirements, more and more industrial flue gas purification devices adopt dry/semi-dry desulfurization devices such as a Circulating Fluidized Bed (CFB), a rotary Spray Drying (SDA) and a dry absorbent injection Desulfurization (DSI). The dry desulphurized ashes thus produced are also increasing, with the national one in 2018 estimated to be over 1500 ten thousand tons, with an expectation that after 2020, they will be over 2500 ten thousand tons/year.
The dry desulfurization ash is a dry powdery mixture which is generated by adopting a semi-dry method or a dry desulfurization process (CFB-FGD, SDA, DSI and the like) and has high calcium sulfite content, mainly comprises calcium sulfite hemihydrate, calcium sulfate, calcium carbonate, calcium hydroxide, fly ash and the like, has low water content (generally lower than 2 percent), and belongs to general industrial solid wastes. With the comprehensive popularization of the dry desulfurization process in China, the dry desulfurization ash is generated in an increasing amount, and a comprehensive utilization channel which is large in batch, good in economical efficiency and capable of being accepted by the market needs to be found. China has large cement yield and wide distribution, and is one of important ways for consuming industrial ash. Although the dry desulfurized fly ash contains a large amount of calcium sulfite similar to the calcium sulfite in the desulfurized gypsum, the research finds that the direct use of the dry desulfurized fly ash containing calcium sulfite as a cement retarder has two problems: firstly, the slow setting time of partial clinker is too long; secondly, the adaptability to different clinkers is poor. The reasons for the above problems mainly include: firstly, different from the traditional cement retarder, namely calcium sulfate, the solubility of calcium sulfite is small, and the calcium sulfite is different from the reaction products of tricalcium aluminate and tetracalcium aluminoferrite in cement, so that the retarding effect and the adaptability are greatly different; secondly, although calcium sulfite is oxidized into an exothermic reaction, the gas-solid reaction is difficult to carry out under the condition of lower temperature; thirdly, the calcium sulfite can be decomposed under the conditions of high temperature and oxygen deficiency to causeSO2And in addition, at the high temperature of above 900 ℃, calcium carbonate begins to be largely decomposed, which may cause the calcium oxide content in the final product to be too high, and the retarding effect of cement is influenced, so that the dry-process desulfurized ash after oxidation cannot be used as a cement retarder.
Although a few studies show that calcium sulfite in the dry-process desulfurized fly ash can be oxidized into calcium sulfate under proper temperature, time and oxygen conditions and can be used as a cement retarder instead of natural gypsum, and some colleges, scientific research institutions and enterprises are also actively developing desulfurized fly ash oxidation technologies and equipment; however, most of them use catalytic oxidation method, i.e. adding catalyst such as potassium permanganate, acetic acid, manganese dioxide, etc. under normal temperature condition to promote the oxidation of desulfurized ash, which on one hand has long oxidation time and low efficiency, and on the other hand not only consumes catalyst but also introduces unnecessary impurities.
In addition, there are patents disclosing CaSO in high temperature oxidative desulfurization ash3The technical scheme of (1) is that, as disclosed in Chinese patent publication No. CN102319714A, "calcium oxide based dry or semi-dry flue gas desulfurization slag using waste heat of liquid steel slag", and Chinese patent publication No. CN102701618A "calcium sulfite type desulfurization gypsum is put into a fluidized bed furnace and fired at 480-500 ℃ for 20-40 min and then the main component of calcium sulfite is oxidized into type II anhydrous gypsum", and Chinese patent publication No. CN102010146A "refined desulfurization ash is put into a closed container at 450-700 ℃ and oxygen or air is blown into the closed container to react for 20-60 min; the method and the device can realize the CaSO in the desulfurized fly ash3However, due to the technology, process and equipment, it is difficult to ensure the stability and balance of the oxidation conditions such as temperature, time and oxygen atmosphere, and the conditions of industrial production are not available due to high energy consumption and high cost.
The technical scheme disclosed by the patent application numbers 201410380659.4, 201410380382.5 and 201020627340.4 is that the desulfurized ash is heated and oxidized in two stages, the heat source adopts coal, a gas boiler or high-temperature flue gas, the rotary kiln equipment is heated after heat exchange, and the oxygen content in the kiln is ensured to be 20-25% by using external oxygen. However, the above technical solutions have the following disadvantages: firstly, the patent with application numbers 201410380659.4 and 201020627340.4 adopts an external heating furnace to generate high-temperature hot flue gas, needs to burn a large amount of fuel, has high energy consumption, and under the current environment-friendly situation, the external heating furnace only can adopt natural gas or coal gas as the fuel, has high fuel cost, and inevitably causes high oxidation cost of the dry-process desulfurized ash. Although the patent with the application number of 201410380382.5 adopts high-temperature flue gas at 600-800 ℃ generated by a power generation boiler or a sintering machine, the high-temperature flue gas is a medium which is used for power generation or recycling in the main process of the power generation boiler and the sintering machine and is used for heating a heating section of a rotary oxidation kiln, heat loss of the high-temperature flue gas is brought, the temperature of the cited high-temperature flue gas is obviously reduced, the main process of the power generation boiler and the sintering machine is influenced, and the actual application possibility is low; secondly, the above patent requires that the oxygen content in the kiln must be 20-25%, so that oxygen supply equipment must be additionally added in the technology, which greatly increases the cost and increases the control difficulty; thirdly, the dry-method desulfurized fly ash and the gas are in a relative separation state in the rotary kiln, the contact is insufficient, the oxidation speed of the dry-method desulfurized fly ash is slow, the dry-method desulfurized fly ash needs to stay in the rotary kiln for a long time, and the specification and the length of the rotary kiln to be manufactured are large; finally, the oxidizing air passes through the kiln, and the heating heat source is arranged outside the kiln, so that the heating of the outer wall is uneven, the oxidizing section is inevitably subjected to local high temperature, and hardening is easy to occur.
Disclosure of Invention
In view of the above, the present invention aims to provide a method for treating dry desulfurized ash, which has the advantages of high heat and mass transfer efficiency, shortened oxidation time, wider temperature range, and wider requirement for oxygen content, thus having better adaptability, operability and economy, and the treated product is suitable for further application as a cement retarder.
The invention provides a method for treating dry desulfurization ash, which comprises the following steps:
a) the oxidized hot air and the dry-method desulfurized fly ash to be treated enter an oxidation device to be contacted with each other, and oxidized high-temperature desulfurized fly ash and oxidized hot air are respectively obtained; the oxygen content of the oxidation hot air is 15-22%, and the temperature is 400-900 ℃;
b) cooling the oxidized high-temperature desulfurized fly ash obtained in the step a) to obtain a treated product.
Preferably, the dry desulphurized ash in step a) comprises the following components:
15-70 wt% of calcium sulfite;
5-40 wt% of calcium carbonate;
2 to 45 weight percent of calcium hydroxide;
the water content of the dry desulfurization ash is 0-2 wt%.
Preferably, the oxidation device in the step a) is an ebullated bed, a fluidized bed or a strong mixed flow rotary kiln.
Preferably, the temperature of said contacting in step a) is from 400 ℃ to 900 ℃.
Preferably, the temperature after cooling in step b) is less than 80 ℃.
Preferably, the step a) further comprises:
mixing industrial hot air with air to obtain oxidized hot air; the oxygen content of the industrial hot air is 12-22%, and the temperature is 400-1200 ℃.
Preferably, the volume ratio of the industrial hot air to the air is 1: (0-2).
Preferably, the step a) further comprises:
exchanging heat between the industrial hot air and air to obtain oxidized hot air; the temperature of the industrial hot air is 400-1200 ℃.
Preferably, the step a) further comprises:
and sending the obtained oxidized hot air to a hot air recycling device for continuous utilization.
The invention provides a method for treating dry desulfurization ash, which comprises the following steps: a) the oxidized hot air and the dry-method desulfurized fly ash to be treated enter an oxidation device to be contacted with each other, and oxidized high-temperature desulfurized fly ash and oxidized hot air are respectively obtained; the oxygen content of the oxidation hot air is 15-22%, and the temperature is 400-900 ℃; b) cooling the oxidized high-temperature desulfurized fly ash obtained in the step a) to obtain a treated product. Compared with the prior art, the treatment method provided by the invention has the advantages that the oxidized hot air is directly and fully contacted and oxidized with the dry-method desulfurized ash, the heat transfer efficiency and the mass transfer efficiency are high, the oxidation time is shortened, the temperature range is wider, the requirement on the oxygen content is wider, the oxidized hot air is sent to a hot air recycling device for continuous utilization, the adaptability, the operability and the economy are better, and the treated product is suitable for being further applied as a cement retarder.
In addition, the treatment method provided by the invention can adopt oxygen-enriched industrial hot air as a heat source, does not need to consume fuel additionally, saves energy and greatly reduces the oxidation cost.
Drawings
FIG. 1 is a process flow diagram of a method for treating dry desulfurized fly ash according to example 1 of the present invention.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments of the present invention, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention provides a method for treating dry desulfurization ash, which comprises the following steps:
a) the oxidized hot air and the dry-method desulfurized fly ash to be treated enter an oxidation device to be contacted with each other, and oxidized high-temperature desulfurized fly ash and oxidized hot air are respectively obtained; the oxygen content of the oxidation hot air is 15-22%, and the temperature is 400-900 ℃;
b) cooling the oxidized high-temperature desulfurized fly ash obtained in the step a) to obtain a treated product.
Firstly, oxidizing hot air and dry-process desulfurized fly ash to be treated are fed into an oxidizing device to be contacted, so as to respectively obtain oxidized high-temperature desulfurized fly ash and oxidized hot air. In the present invention, the oxygen content of the oxidizing hot air is 15% to 22%, preferably 21%; the temperature of the oxidation hot air is 400-900 ℃, and is preferably 750 ℃.
In a preferred embodiment of the present invention, the oxidizing hot wind is industrial hot wind well known to those skilled in the art; the source of the industrial hot air is not particularly limited, and the hot air of the grate cooler at the kiln head of the cement plant or the hot air of the grate cooler at the tail of the sintering machine (such as tertiary air of a cement kiln or cooling air of the kiln head of the cement kiln) which is well known by a person skilled in the art can be adopted.
In a preferred embodiment of the present invention, the preparation method of the oxidized hot air specifically comprises:
mixing industrial hot air with air to obtain oxidized hot air; the oxygen content of the industrial hot air is preferably 12-22%, and more preferably 21%; the temperature of the industrial hot air is preferably 400-1200 ℃, and more preferably 900 ℃; the volume ratio of the industrial hot air to the air is preferably 1: (0-2).
In another preferred embodiment of the present invention, the preparation method of the oxidized hot wind specifically comprises:
exchanging heat between the industrial hot air and air to obtain oxidized hot air; the temperature of the industrial hot air is preferably 400-1200 ℃.
The invention adopts the oxygen-enriched industrial hot air as a heat source, does not need to consume fuel additionally, saves energy and greatly reduces the oxidation cost.
In the present invention, the dry desulphurized ash preferably comprises the following components:
15-70 wt% of calcium sulfite;
5-40 wt% of calcium carbonate;
2 to 45 weight percent of calcium hydroxide;
more preferably:
35-65 wt% of calcium sulfite;
5-40 wt% of calcium carbonate;
2 to 45 weight percent of calcium hydroxide.
The source of the dry desulfurization ash is not particularly limited, and a dry powdery mixture with high calcium sulfite content is generated by a semi-dry method or a dry desulfurization process well known to a person skilled in the art; the semi-dry or dry desulfurization process includes circulating fluidized bed dry desulfurization (CFB), rotary Spray Drying (SDA), Novel Integrated Desulfurization (NID), dense phase drying tower and pipeline injection (DSI), etc., which are well known to those skilled in the art. In the invention, the water content of the dry desulfurization ash is preferably 0-2 wt%.
In the invention, in the process of enabling the oxidizing hot air and the dry desulfurization ash to be treated to enter the oxidizing device together for contact, the flow rate of the oxidizing hot air is preferably 10000m3/h～30000m3H, more preferably 20000m3H; the treatment capacity of the dry desulfurization ash to be treated is preferably 4t/h to 8t/h, and more preferably 6 t/h.
The method for feeding the dry desulfurization ash to be treated into the oxidation device is not particularly limited, and the dry desulfurization ash to be treated is transported to a desulfurization ash bin for storage by a tank car and then fed into the oxidation device by a feeding machine, which is well known to those skilled in the art.
In the invention, the oxidation device is preferably a fluidized bed, a fluidized bed or a strong mixed flow rotary kiln (a mixed flow device is arranged in the oxidation device to ensure that the powder is fully mixed and contacted with hot air), and is more preferably a fluidized bed. In the preferred embodiment of the invention, the oxidation device is a fluidized bed, and the specific process is that bulk materials are placed on a pore plate, and gas is conveyed from the lower part of the pore plate to cause the material particles to move on a gas distribution plate and to be in a suspension state in the gas flow, so that a mixed bottom layer of the material particles and the gas is generated just like liquid boiling; the material particles in the fluidized bed are fully contacted with the gas in the mixed bottom layer to carry out heat transfer and chemical reaction between the material and the gas; it has the advantages of high heat and mass transfer rate, high drying rate, high heat efficiency, compact structure, low cost, easy operation, etc.
In the present invention, the temperature of the contact is preferably 400 to 900 ℃, more preferably 750 ℃.
The invention adopts a mode of directly contacting the dry desulfurization ash with the oxidation hot air to realize direct and full contact, and adopts the oxidation devices such as a fluidized bed furnace and a fluidized bed, so that the material particles are in a suspension state, thereby having the characteristics of high-efficiency mass transfer and heat transfer, the particles are fully contacted with the oxidation hot air, the system is simple, the rapid oxidation can be realized, and the problems of device hardening and the like can not exist.
Respectively obtaining oxidized high-temperature desulfurized fly ash and oxidized hot air, and cooling the oxidized high-temperature desulfurized fly ash to obtain a treated product; and meanwhile, the obtained oxidized hot air is sent to a hot air recycling device for continuous utilization. In the present invention, the temperature after cooling is preferably less than 80 ℃, more preferably less than 50 ℃.
The product obtained after cooling is sent into a finished product storage bin; the treated product provided by the invention can solve the problems of long setting time and low adaptability to clinker when the dry-process desulfurized ash is directly used as a cement retarder; the reasons for the above problems mainly include: firstly, different from the traditional cement retarder, namely calcium sulfate, the solubility of calcium sulfite is small, and the calcium sulfite is different from the reaction products of tricalcium aluminate and tetracalcium aluminoferrite in cement, so that the retarding effect and the adaptability are greatly different; the invention converts the calcium sulfite in the dry desulphurization ash into calcium sulfate which is the same as the mineral component of the traditional cement retarder in an oxidation mode; secondly, although calcium sulfite is oxidized into an exothermic reaction, the gas-solid reaction is difficult to carry out under the condition of lower temperature; on one hand, the invention utilizes high-temperature industrial hot air with higher oxygen content to directly react with the dry-method desulfurized fly ash; on the other hand, the high-temperature gas is fully contacted with the dry-method desulfurized fly ash solid particles through an oxidation device such as a fluidized bed or a strong mixed flow rotary kiln, and the oxidation rate is greatly enhanced through high-efficiency mass transfer and heat transfer effects; thirdly, the calcium sulfite can be decomposed under the conditions of high temperature and oxygen deficiency to cause SO2In addition, at the high temperature of above 900 ℃, calcium carbonate begins to decompose in large quantity, possibly causing the content of calcium oxide in the final product to be too high, and influencing the retarding effect of cement, so that the oxidized dry-process desulfurized ash cannot be used as a cement retarder; the invention selects proper temperature interval, gas-solid ratio and heat source through optimizationOxygen content, gas-solid contact mode and other parameters, on one hand, the oxidation rate of calcium sulfite in the desulfurized fly ash is improved, and on the other hand, the decomposition of calcium sulfite and calcium carbonate is minimized.
In the invention, the process of oxidizing the calcium sulfite in the dry desulfurization ash into the calcium sulfate is an exothermic reaction, so the temperature of the oxidized hot air is basically not reduced or slightly reduced, the hot air can be returned to the main process for providing the industrial hot air for recycling according to the situation, and the energy consumption of the main process cannot be increased.
The invention provides a method for treating dry desulfurization ash, which comprises the following steps: a) the oxidized hot air and the dry-method desulfurized fly ash to be treated enter an oxidation device to be contacted with each other, and oxidized high-temperature desulfurized fly ash and oxidized hot air are respectively obtained; the oxygen content of the oxidation hot air is 15-22%, and the temperature is 400-900 ℃; b) cooling the oxidized high-temperature desulfurized fly ash obtained in the step a) to obtain a treated product; and simultaneously sending the oxidized hot air obtained in the step a) to a hot air recycling device for continuous utilization. Compared with the prior art, the treatment method provided by the invention has the advantages that the oxidized hot air is directly and fully contacted and oxidized with the dry-method desulfurized ash, the heat transfer efficiency and the mass transfer efficiency are high, the oxidation time is shortened, the temperature range is wider, the requirement on the oxygen content is wider, the oxidized hot air is sent to a hot air recycling device for continuous utilization, the adaptability, the operability and the economy are better, and the treated product is suitable for being further applied as a cement retarder.
In addition, the treatment method provided by the invention can adopt oxygen-enriched industrial hot air as a heat source, does not need to consume fuel additionally, saves energy and greatly reduces the oxidation cost.
To further illustrate the present invention, the following examples are provided for illustration. The dry desulphurisation ash to be treated used in the following examples of the invention is derived from a Circulating Fluidized Bed (CFB) desulphurisation process wherein the amount of calcium sulphite present in the dry desulphurisation ash to be treated in example 1 is 45 wt% and the amount of calcium sulphite present in the dry desulphurisation ash to be treated in example 2 is 35 wt%.
Example 1
A process flow diagram of the method for treating the dry desulfurization ash provided in embodiment 1 of the present invention is shown in fig. 1, wherein 1 is high-temperature hot air, 2 is cold air at normal temperature, 3 is a mixed preparation device of oxidizing hot air, 4 is a heat exchanger, 5 is oxidizing hot air, 6 is dry desulfurization ash to be treated, 7 is a fluidized bed/rotary kiln oxidation device, 8 is oxidized high-temperature desulfurization ash, 9 is a cooling device, 10 is a cooled oxidation product, 11 is a finished product storage bin, 12 is oxidized hot air, and 13 is a plant hot air recycling device.
The method comprises the following specific steps:
(1) the high-temperature hot air (1) comes from tertiary air of a novel cement kiln, and the oxygen content of the high-temperature hot air is 21 percent and the temperature of the high-temperature hot air is 900 ℃; mixing the high-temperature hot air (1) and the normal-temperature cold air (2) according to a volume ratio of 4: 8, mixing in an oxidizing hot air mixing preparation device (3) to obtain oxidizing hot air (5); the oxygen content of the oxidation hot air (5) is 21 percent, and the temperature is 750 ℃.
(2) The oxidation hot air (5) and the dry desulphurization ash (6) to be treated enter a fluidized bed oxidation device (7) together; the treatment capacity of the dry desulfurization ash (6) to be treated is 6 tons/hour, and the flow of the oxidation hot air (5) is 20000m3H; the internal temperature of the fluidized bed oxidation device (7) is 800 ℃, and the retention time is 1 min; and then, performing high-temperature cyclone dust removal and collection, wherein the efficiency exceeds 80%, obtaining oxidized high-temperature desulfurized ash (8), cooling the oxidized high-temperature desulfurized ash to 50 ℃ by a cooling device (9), and then entering a finished product storage bin (11) to obtain a finished product.
Meanwhile, the oxidized hot air (12) enters an in-plant hot air recycling device (13), and the embodiment 1 is specifically a decomposition kiln of a cement main process production line, so that the hot air is continuously utilized and the main process is not influenced.
Through detection, the treated product obtained in the finished product storage bin (11) has the calcium sulfate content of more than 40 wt% and the calcium oxide content of less than 8 wt%, and can be directly used as a retarder in a cement clinker mill.
The performance of the dry desulfurized fly ash as a cement retarder before and after treatment according to the treatment method provided in example 1 of the present invention was tested, and the results are shown in table 1.
TABLE 1 comparative data on the performance of dry desulfurized fly ash as a cement retarder before and after treatment according to the treatment method provided in example 1 of the present invention
| Retarder | Cement clinker | Mixing amount of retarder | Initial setting | Final setting |
| Dry desulfurized fly ash to be treated | 94％ | 6％ | 320min | 400min |
| Treated product | 94％ | 6％ | 128min | 190min |
Example 2
The process flow diagram of the method of treating dry desulphurised ash provided in example 1; the method comprises the following specific steps:
(1) the high-temperature hot air (1) comes from a novel cement kiln head cooling air (generally used for waste heat power generation) high-temperature section, the oxygen content of the high-temperature hot air is 21%, and the temperature of the high-temperature hot air is 500 ℃; the high-temperature hot air (1) is directly used as oxidizing hot air (5) without treatment.
(2) Mixing the hot oxidizing air (5) with the air to be treatedThe treated dry desulfurization ash (6) enters a rotary kiln oxidation device (7) together; the treatment capacity of the dry desulfurization ash (6) to be treated is 6 tons/hour, and the flow of the oxidation hot air (5) is 20000m3H; the internal temperature of the rotary kiln oxidation device (7) is 450 ℃, and the retention time is 1 min; and then, performing high-temperature cyclone dust removal and collection, wherein the efficiency exceeds 80%, obtaining oxidized high-temperature desulfurized ash (8), cooling the oxidized high-temperature desulfurized ash to 50 ℃ by a cooling device (9), and then entering a finished product storage bin (11) to obtain a finished product.
Meanwhile, the oxidized hot air (12) enters an in-plant hot air recycling device (13), and the embodiment 2 is a cement kiln head waste heat power generation system, so that the hot air is continuously utilized and the main process is not influenced.
Through detection, the treated product obtained in the finished product storage bin (11) has the calcium sulfate content of more than 35 wt% and the calcium oxide content of less than 8 wt%, and can be directly used as a retarder in a cement clinker mill.
The performance of the dry desulfurized fly ash as a cement retarder before and after the treatment according to the treatment method provided in example 2 of the present invention was tested, and the results are shown in table 2.
Table 2 comparative data on performance of dry desulfurized fly ash as a cement retarder before and after treatment according to the treatment method provided in example 2 of the present invention
| Retarder | Cement clinker | Mixing amount of retarder | Initial setting | Final setting |
| Dry desulfurized fly ash to be treated | 94％ | 6％ | 285min | 362min |
| Treated product | 94％ | 6％ | 156min | 220min |
As can be seen from tables 1-2, compared with the dry desulfurization ash to be treated, the main component of the treated product is calcium sulfate, the content of calcium sulfite is low, the adaptability to cement clinker is good, and the setting time can be adjusted within the range of 100-200 min.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (4)
1. A method for treating dry desulfurization ash comprises the following steps:
a) the oxidized hot air and the dry-method desulfurized fly ash to be treated enter an oxidation device to be contacted with each other, and oxidized high-temperature desulfurized fly ash and oxidized hot air are respectively obtained; the oxygen content of the oxidation hot air is 15-22%, and the temperature is 400-900 ℃; the oxidation device is a fluidized bed, a fluidized bed or a strong mixed flow rotary kiln; the contact temperature is 400-900 ℃;
the preparation method of the oxidized hot air comprises the following specific steps:
mixing industrial hot air with the oxygen content of 12-22% and the temperature of 400-1200 ℃ with air to obtain oxidized hot air; the volume ratio of the industrial hot air to the air is 1: (0-2);
or the like, or, alternatively,
exchanging heat between the industrial hot air with the temperature of 400-1200 ℃ and air to obtain oxidized hot air; b) cooling the oxidized high-temperature desulfurized fly ash obtained in the step a) to obtain a treated product.
2. The treatment process according to claim 1, characterized in that said dry desulphurized ash in step a) comprises the following components:
15-70 wt% of calcium sulfite;
5-40 wt% of calcium carbonate;
2 to 45 weight percent of calcium hydroxide;
the water content of the dry desulfurization ash is 0-2 wt%.
3. The process of claim 1, wherein the temperature after cooling in step b) is less than 80 ℃.
4. The process of any one of claims 1 to 3, wherein step a) further comprises:
and sending the obtained oxidized hot air to a hot air recycling device for continuous utilization.
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| CN102701618A (en) * | 2012-06-25 | 2012-10-03 | 甘肃省建材科研设计院 | Method for using calcium sulfite type desulfurization gypsum to produce high-strength environmental-friendly type plastering gypsum |
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| CN102701618A (en) * | 2012-06-25 | 2012-10-03 | 甘肃省建材科研设计院 | Method for using calcium sulfite type desulfurization gypsum to produce high-strength environmental-friendly type plastering gypsum |
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