CN109082709B - Method for synthesizing calcium sulfate whiskers by using sintered flue gas desulfurization ash through one-step method - Google Patents
Method for synthesizing calcium sulfate whiskers by using sintered flue gas desulfurization ash through one-step method Download PDFInfo
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Abstract
The invention discloses a method for removing impurities by using sintering flue gasA method for synthesizing calcium sulfate whiskers by using sulfur ash in one step, belonging to the technical field of resource recovery and reuse. The invention mixes the pretreated desulfurization ash with MgCl2Stirring the solution to obtain slurry, and adding saturated Ca (OH) dropwise into the slurry2And adjusting the pH value of the slurry to be between 8 and 9, and transferring the slurry to a high-pressure reaction kettle for hydro-thermal synthesis to obtain the calcium sulfate whisker. The method takes the sintering flue gas desulfurization ash as a raw material, adopts the hydrothermal system to oxidize and prepare the calcium sulfate whisker synergistically, realizes the synergistic preparation of the calcium sulfate whisker by oxidizing the sintering flue gas desulfurization ash, and solves the problem of CaSO3Difficult rapid oxidation and longer process flow of the preparation process of the calcium sulfate whisker, improves the recovery utilization rate of the desulfurized fly ash and improves the quality of the calcium sulfate whisker.
Description
Technical Field
The invention relates to the field of resource recycling, in particular to a method for synthesizing calcium sulfate whiskers by using sintered flue gas desulfurization ash in a one-step method.
Background
With country to SO2Pollution (b) byThe control enhancement and the enhancement of the environmental protection consciousness in China are gradually concerned by people in the research of the comprehensive utilization aspect of the sinter flue gas desulfurization ash, and the utilization of the sinter flue gas desulfurization ash can reduce the fund consumed by stacking, land occupation and environmental pollution, reduce the consumption of natural gypsum, further reduce the exploitation amount of the natural gypsum and protect the ecological environment. Therefore, many colleges and enterprises have conducted a great deal of research on the comprehensive utilization of the sintered ore flue gas desulfurization ash, such as preparation of sulfuric acid, cement retarders, gypsum building materials, calcium sulfate whiskers and the like by using the sintered flue gas desulfurization ash. The calcium sulfate whisker prepared by sintering flue gas desulfurization ash has higher added value, is a short fiber grown in a single crystal form, has uniform cross section, complete appearance and highly perfect internal structure, and has the advantages of extremely high strength, fine size, easy combination with organic high molecular compounds such as resin, rubber, plastic and the like and excellent appearance quality compared with glass fiber. The method for preparing the calcium sulfate whiskers by using the desulfurized gypsum as the raw material can reduce the pollution of the desulfurized gypsum to the environment, can save natural gypsum resources, and opens up a new way for the high added value utilization of the desulfurized gypsum, but the existing method for preparing the calcium sulfate whiskers by using the desulfurized ash is still imperfect, so that the quality of the calcium sulfate whiskers is poor, and the high-efficiency resource application of the desulfurized ash is severely limited.
Through patent retrieval, Stepeyang of the university in northeast has also carried out related research, and related patents are applied, a method for preparing calcium sulfate whiskers by using sintering ore flue gas desulfurization byproducts (application No. 201010545829.1; application No. 2010.11.16) and a method for preparing calcium sulfate whiskers by using flue gas desulfurization gypsum (application No. 200810011193.5; application No. 2008.04.25), and the method provides a way for resource utilization of the desulfurization byproducts. However, the quality of the calcium sulfate whisker produced by the existing method is poor, and the high value-added application of the desulfurization byproduct is limited. In addition, the name of the invention is as follows: apparatus for treating semidry desulfurized fly ash (patent application No. CN201610076883.3, application publication No. 2016.05.04) by passing it through a heating furnaceAn adsorption tower is arranged above the semi-dry desulfurization ash, the flue gas generated by heating the semi-dry desulfurization ash is cooled by cold air blown by a draught fan in an air inlet flue and then enters a lower adsorption chamber, and the active coke in the lower adsorption chamber is used for treating SO in the flue gas2Carrying out first adsorption, then making the flue gas pass through the transition flue and enter into the upper adsorption chamber, and making the active coke in the upper adsorption chamber to make SO in the flue gas2And carrying out secondary adsorption, and then discharging the flue gas from a chimney after the flue gas enters the air outlet flue. Therefore, the desulfurization treatment of the semi-dry desulfurization ash is rapidly realized, the problem of secondary pollution of the semi-dry desulfurization ash is solved, and the technical problem of reutilization of the desulfurization ash is still not solved. In addition, the name of the invention is as follows: a desulfurization ash treatment apparatus and method (patent application No. CN201610344246.X, application publication No. 2016.10.12) by providing a desulfurization ash treatment apparatus comprising: the device comprises a vertical mill, a dust collector, a hot blast stove, a primary hot blast pipe and a secondary hot blast pipe; a slag inlet for slag to enter is formed in the vertical mill; the dust collector is connected with the vertical mill; the joint of the primary hot air pipe and the secondary hot air pipe is provided with an air mixing inlet. Through oxidizing and modifying the desulfurized fly ash in hot air, the formed slag powder product is greatly shortened in setting time, the investment of low-temperature calcination equipment and the process cost are saved, the technical problems that the treatment cost is increased and a new pollution source is formed due to a desulfurized fly ash treatment mode in the prior art are effectively solved, and the problem of separation of iron powder in the desulfurized fly ash is still not solved.
Disclosure of Invention
1. Technical problem to be solved by the invention
Aiming at the problem of poor quality of the calcium sulfate whisker prepared from the desulfurization ash in the prior art, the invention provides a method for synthesizing the calcium sulfate whisker by using the sintering flue gas desulfurization ash in one step.
2. Technical scheme
In order to achieve the purpose, the technical scheme provided by the invention is as follows:
the invention discloses a method for synthesizing calcium sulfate whiskers by using sintered flue gas desulfurization ash in one step, which comprises the following steps of
The method comprises the following steps: pretreatment of desulfurized fly ash
Separating iron powder from the desulfurized fly ash, and screening out large-particle insoluble substances in the desulfurized fly ash to obtain pretreated desulfurized fly ash;
step two: preparation of calcium sulfate whisker
Mixing the pretreated desulfurized fly ash with MgCl2Mixing the solutions to obtain slurry, transferring the slurry into a high-pressure reaction kettle of a reaction device, introducing oxygen into the high-pressure reaction kettle, and adjusting the pressure in the high-pressure reaction kettle to be 1-2 MPA and the temperature to be 120-180 ℃; thereby synthesizing the calcium sulfate whisker in the high-pressure reaction kettle in a hydrothermal way.
Preferably, the step two comprises the following steps:
(1) MgCl with a concentration of 2% is prepared2The solution acts as a habit modifier to MgCl2Adding the solution into the pretreated desulfurized ash, and uniformly stirring to obtain slurry, wherein the solid-to-liquid ratio of the slurry is controlled to be 1/15-1/20;
(2) to the slurry was added dropwise saturated Ca (OH)2Adjusting the pH of the slurry to 8-9;
(3) adding the slurry into a high-pressure reaction kettle, closing a top cover of the high-pressure reaction kettle, then filling oxygen into the high-pressure reaction kettle, and stirring the slurry in the high-pressure reaction kettle, wherein the stirring strength is 400-600r/min, and the reaction time is 2-3 h, so that the calcium sulfate whisker is hydrothermally synthesized in the high-pressure reaction kettle.
Preferably, the step of the step one is: adding the desulfurized ash into a desulfurized ash and iron powder separating device to separate iron powder, blowing the desulfurized ash into an iron powder recovery cavity by blowing air flow generated by an air inlet pipe of the desulfurized ash and iron powder separating device, and adsorbing the iron powder in the desulfurized ash onto the surface of a cotton sleeve by generating magnetic force by an electromagnet; the desulfurized ash after the iron powder is separated after the blowing air flow of the air inlet pipe is closed falls into the recovery tank under the action of gravity; and taking the desulfurized fly ash separated from the iron powder out of the recovery tank, mixing the desulfurized fly ash with water, screening out large-particle insoluble substances in the desulfurized fly ash, and carrying out vacuum filtration on the desulfurized fly ash from which the large-particle insoluble substances are screened out to obtain pretreated desulfurized fly ash.
Preferably, reaction unit includes oxygen cylinder and high pressure batch autoclave, and the oxygen cylinder passes through the air inlet at pipeline and high pressure batch autoclave top and links to each other, is provided with the oxygen valve on the air inlet, is provided with the relief valve on the pipeline between air inlet and the high pressure batch autoclave, be provided with the barometer on the high pressure batch autoclave, be provided with stirring vane in the high pressure batch autoclave.
Preferably, the step one: the method comprises the following specific steps of desulfurization ash pretreatment:
(1) adding the desulfurized ash into a desulfurized ash and iron powder separating device of an iron powder recovery device, starting an electromagnet, simultaneously opening an air valve of a back-blowing air tank, making back-blowing air in the back-blowing air tank flow into the cylinder core of an electromagnet iron core through a pipeline, and then making the back-blowing air flow overflow to the outside of the electromagnet through an air vent on the surface of the iron core;
(2) starting a blast fan, and spraying blowing air flow generated by the blast fan into the iron powder recovery cavity from bottom to top through an air inlet pipe;
(3) conveying the desulfurized ash into an air inlet pipe through a desulfurized ash groove;
(4) the blowing air flow of the air inlet pipe blows the desulfurized ash into the iron powder recovery cavity, and the iron powder in the desulfurized ash is adsorbed on the surface of the cotton sleeve;
(5) closing the blowing air flow of the air inlet pipe, and dropping the desulfurized fly ash after separating the iron powder into the recovery tank under the action of gravity;
(6) and (3) mixing the desulfurized ash removed of the iron powder from the recovery tank with water, screening out large-particle insoluble substances, and placing the desulfurized ash screened out of the large-particle insoluble substances in a suction filtration device for vacuum filtration to obtain the pretreated desulfurized ash.
Preferably, in the first step (1), the blowback air flow in the blowback tank enters the first air flow branch pipe and the second air flow branch pipe through the main air flow pipe, and simultaneously controls the flow rates of the first blowback valve and the second blowback valve.
Preferably, the desulfurization ash is added into the desulfurization ash groove in the step one (3), the air valve of the pressurization air tank is opened, the pressurization air tank pressurizes the desulfurization ash groove, then the material valve is opened, and the desulfurization ash in the desulfurization ash groove is conveyed into the air inlet pipe through the conveying pipe.
Preferably, in the step one (4), the desulfurization ash is injected into the iron powder recovery cavity by the injection airflow of the air inlet pipe, the desulfurization ash is injected to the periphery of the electromagnet under the action of the injection airflow, the iron powder in the desulfurization ash is adsorbed on the surface of the cotton sleeve by the electromagnet, and meanwhile, the blowback airflow overflows outwards through the vent holes in the surface of the iron core of the electromagnet, so that the desulfurization ash is prevented from permeating into the cotton sleeve.
Preferably, the iron powder recovery device comprises a desulfurization ash and iron powder separation device, a desulfurization ash and iron powder separation device and a desulfurization ash and iron powder separation device, wherein the desulfurization ash and iron powder separation device comprises an air inlet pipe, an iron powder recovery cavity, a top cover and a back-blowing air tank; an electromagnet and a cotton sleeve are arranged in the iron powder recovery cavity, the cotton sleeve is wrapped outside the electromagnet, the electromagnet comprises a lead and an iron core, the lead is wound outside the iron core, and the surface of the iron core is provided with an air vent which is communicated with the cylinder core of the iron core; the top cover is arranged at the top of the iron powder recovery cavity, and a filter layer is arranged inside the top cover; the air inlet pipe is arranged at the bottom of the iron powder recovery cavity, and the desulfurized ash enters the iron powder recovery cavity through the air inlet pipe; the back-blowing gas tank is connected with the cylinder core of the iron core through a gas pipeline, and a recovery tank is arranged at the bottom of the air inlet pipe.
3. Advantageous effects
Compared with the prior art, the technical scheme provided by the invention has the following remarkable effects:
(1) the invention discloses a method for synthesizing calcium sulfate whiskers by using sintered flue gas desulfurization ash in one step2The solution is fully and uniformly stirred to obtain slurry, and then the slurry is transferred to a high-pressure reaction kettle of a reaction device to carry out hydro-thermal synthesis to obtain calcium sulfate whiskers; by separating and removing the iron powder in the desulfurized fly ash, the iron powder doped in the desulfurized fly ash and CaSO in the desulfurized fly ash can be avoided in a hydrothermal system3Compete for dissolved oxygen in the slurry and prevent iron powder in the desulfurized ash from becoming crystal attachment points of nascent calcium sulfate, thereby causing a large amount of nucleation of calcium sulfate whiskers and hindering the growth process of the calcium sulfate whiskers, and simultaneously, the method adoptsThe quality of the calcium sulfate whisker can be improved by preparing the calcium sulfate whisker through the oxidation synergy of the hydrothermal system;
(2) according to the method for synthesizing the calcium sulfate whiskers by using the sintered flue gas desulfurization ash one-step method, the desulfurization ash is blown into the iron powder recovery cavity by the blowing air flow of the air inlet pipe, the iron powder in the desulfurization ash is adsorbed on the surface of the cotton sleeve by the magnetic force generated by the electromagnet, the friction force between the iron powder and the surface of the electromagnet is improved by the cotton sleeve, the iron powder adsorbed on the surface of the electromagnet is prevented from being blown down by wind, and the adsorption of the electromagnet on the iron powder is promoted; the electromagnet is started, an air valve of the back-blowing air tank is opened at the same time, back-blowing air in the back-blowing air tank enters the cylinder core of the electromagnet iron core through a pipeline, and then back-blowing air flows overflow from the vent holes on the surface of the iron core to the outside of the electromagnet, so that desulfurization ash is prevented from permeating into gaps of the cotton sleeve under the action of the blowing air flow, and the separation of the desulfurization ash and iron powder is promoted;
(3) the invention relates to a method for synthesizing calcium sulfate whiskers by using sintered flue gas desulfurization ash in one step, which comprises the steps of uniformly mixing desulfurization ash separated from iron powder taken out from a recovery tank with water to obtain a desulfurization ash water solution, then transferring the desulfurization ash water solution into a filter device, removing large-particle insoluble substances in the desulfurization ash through a filter screen, allowing the desulfurization ash water solution to enter a filter in the filter device through holes in the filter screen, allowing the desulfurization ash water solution to enter a filter outlet at the bottom of the filter under the action of gravity, and flowing into a Buchner funnel along the filter outlet, performing vacuum pumping operation by a circulating water vacuum pump to obtain pretreated desulfurization ash, and transferring the pretreated desulfurization ash into a reaction device for hydrothermal synthesis to obtain the calcium sulfate whiskers. Large-particle insoluble substances in the desulfurized fly ash can be removed by using a vacuum pump for suction filtration, and the quality of the calcium sulfate whisker prepared from the desulfurized fly ash is improved.
Drawings
FIG. 1 is a schematic view of the structure of a reaction apparatus of example 1;
FIG. 2 is an SEM image of calcium sulfate whiskers of example 1;
FIG. 3 is an SEM image of calcium sulfate whiskers without iron removal from example 1;
FIG. 4 is a schematic structural view of a suction filtration apparatus according to example 2;
FIG. 5 is a schematic structural view of a filter according to example 2;
FIG. 6 is a schematic view showing the construction of an apparatus for separating iron powder from desulfurized fly ash according to example 2;
FIG. 7 is a schematic top view of the top cover of embodiment 2;
FIG. 8 is a schematic configuration view of an apparatus for separating iron powder from desulfurized fly ash according to example 4;
FIG. 9 is a schematic configuration view of an apparatus for separating iron powder from desulfurized fly ash according to example 5;
FIG. 10 is a flow chart of a method for synthesizing calcium sulfate whiskers by using sintered flue gas desulfurization ash in a one-step method.
The reference numerals in the schematic drawings illustrate:
100. an air inlet pipe; 110. a first air inlet pipe; 120. a second air inlet pipe; 130. the joint of the air pipe; 131. a bellows; 140. a recovery tank; 150. a blower fan; 101. a desulfurized fly ash tank; 102. a delivery pipe; 103. a pressurized gas tank; 104. a material valve;
200. a ferrous powder recovery cavity; 201. a power-on head; 202. a wire; 203. a cotton sleeve; 204. a vent hole; 205. an iron core; 210. a first electromagnet; 220. a second electromagnet; 230. a third electromagnet; 231. a left electromagnet; 232. a right electromagnet; 240. a cavity contraction section;
310. a top cover; 320. a filter layer;
410. a blowback gas tank; 420. a main airflow pipe; 421. a first gas flow branch pipe; 422. a second gas flow branch pipe; 423. a first blowback valve; 424. a second blowback valve;
520. a high-pressure reaction kettle; 521. a pressure relief valve; 522. a barometer; 523. an air inlet; 524. a gas heater; 525. a stirring blade; 526. a heat-insulating layer; 527. a thermometer; 528. an oxygen valve;
601. a suction filtration unit; 602. a filter; 610. a Buchner funnel; 620. an air extraction opening; 630. a vacuum gas pumping bottle; 640. a rubber hose; 650. a circulating water vacuum pump;
710. filtering with a screen; 720. and (6) filtering an outlet.
Detailed Description
The detailed description and exemplary embodiments of the invention will be better understood when read in conjunction with the appended drawings, where the elements and features of the invention are identified by reference numerals.
The structure, ratio, size and the like shown in the drawings of the present specification are only used for matching with the content disclosed in the specification, so as to be known and read by people familiar with the technology, and are not used for limiting the limit conditions which can be implemented by the present invention, so that the present invention does not have the substantial significance in the technology, and any structure modification, ratio relationship change or size adjustment should still fall within the scope which can be covered by the technical content disclosed by the present invention without affecting the efficacy which can be produced by the present invention and the achievable purpose. Meanwhile, the terms such as "upper", "lower", "left", "right", "middle", and the like, referred to in the present specification, are used for clarity of description only, and are not used to limit the implementable scope, and changes or adjustments of the relative relationship thereof are also regarded as the implementable scope of the present invention without substantial changes in the technical content; in addition, the embodiments of the present invention are not independent of each other, but can be combined.
Example 1
As shown in fig. 1, in the method for synthesizing calcium sulfate whiskers by using sintered flue gas desulfurization ash in one step, the desulfurization ash in this embodiment is sintered flue gas desulfurization ash.
The method comprises the following steps: pretreatment of desulfurized fly ash
Separating iron powder from the desulfurized fly ash, and removing large-particle insoluble substances from the desulfurized fly ash to obtain pretreated desulfurized fly ash; the detailed steps are as follows:
(1) adding desulfurized ash into a desulfurized ash and iron powder separating device, starting an electromagnet, simultaneously opening an air valve of a back-blowing air tank 410, enabling back-blowing air in the back-blowing air tank 410 to flow into a cylinder core of an electromagnet iron core 205 through a pipeline, and then enabling back-blowing air flow to overflow to the outside of the electromagnet through an air hole 204 on the surface of the iron core 205;
the blowback air flow in the blowback air tank 410 enters the first air flow branch pipe 421 and the second air flow branch pipe 422 through the air flow main pipe 420, and simultaneously controls the flow of the first blowback valve 423 and the second blowback valve 424;
(2) starting the blast fan 150, and spraying blowing air flow generated by the blast fan 150 into the iron powder recovery cavity 200 from bottom to top through the air inlet pipe 100;
(3) conveying the desulfurized ash into an air inlet pipe 100 through a desulfurized ash tank 101;
adding the desulfurization ash into a desulfurization ash tank 101, starting an air valve of a pressurization air tank 103, pressurizing the desulfurization ash tank 101 by the pressurization air tank 103, then opening a material valve 104, and conveying the desulfurization ash in the desulfurization ash tank 101 into an air inlet pipe 100 through a conveying pipe 102;
(4) the blowing air flow of the air inlet pipe 100 blows the desulfurized fly ash into the iron powder recovery cavity 200, and the iron powder in the desulfurized fly ash is adsorbed on the surface of the cotton sleeve 203;
the blowing air flow of the air inlet pipe 100 blows the desulfurization ash into the iron powder recovery cavity 200, the desulfurization ash is blown to the periphery of the electromagnet under the action of the blowing air flow, the iron powder in the desulfurization ash is adsorbed on the surface of the cotton sleeve 203 by the electromagnet, meanwhile, the blowback air flow overflows outwards through the vent holes 204 on the surface of the electromagnet iron core 205, and the desulfurization ash is prevented from permeating into the cotton sleeve 203;
(5) the desulfurized fly ash after the iron powder is separated after the blowing air flow of the air inlet pipe 100 is closed falls into the recovery tank 140 under the action of gravity;
(6) taking the desulfurized fly ash from which the iron powder is removed out of the recovery tank 140, mixing the desulfurized fly ash with water, screening out large-particle insoluble substances, and placing the desulfurized fly ash from which the large-particle insoluble substances are screened out in a Buchner funnel 610 for vacuum filtration to obtain pretreated desulfurized fly ash;
step two: preparation of calcium sulfate whisker
Mixing the pretreated desulfurized fly ash with MgCl2Mixing the solutions to obtain slurry, transferring the slurry into a high-pressure reaction kettle 520 of a reaction device, introducing oxygen into the high-pressure reaction kettle 520, adjusting the pressure in the high-pressure reaction kettle 520 to be 1-2 MPA and the temperature to be 120-180 ℃, wherein the temperature in the embodiment is 180 ℃; thereby synthesizing the calcium sulfate whisker in the high-pressure reaction kettle 520 by hydrothermal reaction; the method comprises the following specific steps:
(1) MgCl with a concentration of 2% is prepared2The solution acts as a habit modifier to MgCl2Adding the solution into the pretreated desulfurized ash, and uniformly stirring to obtain slurry, wherein the solid-to-liquid ratio of the slurry is controlled to be 1/15-1/20;
(2) to the slurry was added dropwise saturated Ca (OH)2Adjusting the pH of the slurry to 8-9;
(3) adding the slurry into a high-pressure reaction kettle 520, closing the top cover of the high-pressure reaction kettle 520, then filling oxygen into the high-pressure reaction kettle 520, and stirring the slurry in the high-pressure reaction kettle 520, wherein the stirring strength is 400-600r/min, and the reaction time is 2-3 h, so that the calcium sulfate whisker is hydrothermally synthesized in the high-pressure reaction kettle 520; the high-pressure oxygen is an oxidant in an oxidation stage, the magnesium chloride is used as a habit modifier, and the three specific processes of crystallization protection are combined with a crystallization theory:
1) dissolution oxidation process
The fine granularity ensures that the desulfurized fly ash has larger specific surface area, and the hydrothermal system has higher temperature and pressure and can promote CaSO3·0.5H2And (4) dissolving O. SO produced after dissolution3 2-Is oxidized into SO rapidly4 2-The oxidation reaction is carried out uninterruptedly, and CaSO is contained in the desulfurized fly ash3·0.5H2The O is constantly dissolved.
2) Crystallization process
Ca in solution as the dissolution oxidation process continues2+、SO4 2-When the concentration of Ca in the solution is increased2 +、SO4 2-When the temperature reaches a supersaturated state, crystals are precipitated. Experiments show that the reaction conditions are different, and the corresponding reaction products are also different, and the specific reaction equation is as follows:
Ca2++SO4 2-= CaSO4(fibrous)
Ca2++SO4 2-+1/2H2O = CaSO4·1/2H2O (fibrous)
Ca2++SO4 2-+ 2H2O = CaSO4·2H2O (fibrous)
3) Whisker growth process
Ca in solution after crystal nucleation2+、SO4 2-Still in a supersaturated state and still continuously precipitate in the form of crystals. At 180 ℃ in CaSO4Solubility lower than CaSO4·0.5H2O and CaSO4·2H2O，CaSO4Will be rapidly condensed with the crystal nucleus as the center; meanwhile, according to the directional growth characteristic of the calcium sulfate whisker and under the action of a crystal habit modifier, the crystal can continuously grow, and finally the acicular calcium sulfate whisker is formed. SEM pictures of calcium sulfate whiskers prepared using this example are shown in fig. 2.
Comparative example 1
The basic contents of comparative example 1 are the same as example 1, except that: in the first step: in the pretreatment of the desulfurization ash, the iron powder in the desulfurization ash is not separated, but the whisker is prepared directly by the desulfurization ash with the iron powder. SEM pictures of calcium sulfate whiskers prepared using this comparative example are shown in fig. 3.
Comparing fig. 2 and 3, it is shown that the calcium sulfate whiskers produced using example 1 are relatively ordered and that the calcium sulfate whiskers are produced relatively quickly. The reasons for this may be: comparative example 1 in the process of preparing calcium sulfate whiskers, desulfurized fly ash contained a large amount of CaSO3In this embodiment, a physical impurity removal process is introduced, iron powder in desulfurized ash is removed by using an electromagnet, and if the desulfurized ash from which the iron powder is not separated is directly used for hydrothermal reaction to synthesize calcium sulfate whiskers, the iron powder and CaSO in a hydrothermal system can be mixed3The dissolved oxygen in the slurry is strived for, and meanwhile, the iron powder becomes the crystal attachment point of the new calcium sulfate, so that a large amount of calcium sulfate whiskers are nucleated, but the growth is slow, and the removal of the iron powder in the desulfurized fly ash is beneficial to the growth process of the calcium sulfate whiskers. In the process of preparing the calcium sulfate whisker in the embodiment 1, the iron powder in the desulfurized fly ash is physically removed, so that the iron powder in the desulfurized fly ash is effectively removed, and the preparation quality of the calcium sulfate whisker is improved.
It is worth noting that MgCl was formulated at a concentration of 2%2The solution acts as a habit modifier to MgCl2Adding the pretreated desulfurized ash into the solution, uniformly stirring to obtain slurry, controlling the solid-to-liquid ratio of the slurry to be 1/15-1/20, avoiding the desulfurized ash in the slurry from caking, and simultaneously enabling the desulfurized ash to have larger specific surface area due to the finer granularity; adding the slurry which is fully and uniformly stirred into the high-pressure reaction kettle 520, closing the top cover of the high-pressure reaction kettle 520, then filling oxygen into the high-pressure reaction kettle 520, controlling the stirring strength in the high-pressure reaction kettle 520 to be 400-600r/min, and controlling the reaction time to be 2-3 h, so that the hydrothermal system has higher temperature and pressure, and can promote CaSO in the desulfurized ash3·0.5H2Dissolving O, SO produced after dissolving3 2-Is oxidized into SO rapidly4 2-The oxidation reaction is carried out uninterruptedly, and CaSO is contained in the desulfurized fly ash3·0.5H2Continuously dissolving O and Ca in the solution2+、SO4 2-Is always in a supersaturated state, provides power for crystallization and growth of the calcium sulfate whisker, realizes the synergistic preparation of the calcium sulfate whisker by oxidizing the sintering flue gas desulfurization ash, and solves the problem of CaSO3The difficulty of difficult rapid oxidation and long process flow of the preparation of the calcium sulfate whisker, and provides theoretical basis for high value-added resource utilization of the sintering flue gas desulfurization ash.
Example 2
The basic content of this embodiment is the same as embodiment 1, as shown in fig. 4 and 5, except that: adding desulfurized ash into the desulfurized ash and iron powder separating device, wherein when the desulfurized ash moves to the lower part of the iron powder recovery cavity 200, the desulfurized ash moves to the periphery of the first electromagnet 210 and the second electromagnet 220, and the iron powder in the desulfurized ash is adsorbed on the surface of the cotton sleeve 203 by the first electromagnet 210 and the second electromagnet 220; then, the desulfurized fly ash continues to move upwards under the action of the blowing air flow, and when the desulfurized fly ash moves to the periphery of the third electromagnet 230, iron powder in the desulfurized fly ash is adsorbed on the surface of the third electromagnet 230; the desulfurization ash moves to the junction between the left electromagnet 231 and the right electromagnet 232 through the gap between the first electromagnet 210 and the second electromagnet 220 under the effect of the blowing air flow, and is adsorbed on the surface of the junction, so that the separation effect of the iron powder in the desulfurization ash is improved, and after the blowing air flow stops blowing, the desulfurization ash after the iron powder is separated falls into the recovery tank 140 under the action of gravity, so that the desulfurization ash is convenient to collect.
Further, collecting and transferring the desulfurized ash falling into the recovery tank 140 into a suction filtration device, wherein the suction filtration device comprises a filter 602, a circulating water vacuum pump 650 and a suction filtration unit 601, and the circulating water vacuum pump 650 is connected with an extraction opening 620 of the suction filtration unit 601 through a rubber hose 640; the suction filtration unit 601 comprises a Buchner funnel 610, an extraction opening 620 and a vacuum extraction bottle 630, the Buchner funnel 610 is arranged above the vacuum extraction bottle 630, one side of the vacuum extraction bottle 630 is provided with the extraction opening 620, the extraction opening 620 is connected with a circulating water vacuum pump 650 through a rubber hose 640, and the filter 602 is arranged above the Buchner funnel 610; the middle part of the filter 602 is provided with a filter screen 710, the filter aperture of the filter screen 710 is smaller than the diameter of large-particle insoluble substances and larger than the diameter of the desulfurized fly ash, the bottom of the filter 602 is provided with a filter outlet 720, and the filter outlet 720 is arranged at the upper part of the Buchner funnel 610. After iron powder is removed from the desulfurized ash, the desulfurized ash is uniformly mixed with distilled water and then is moved into a filter 602, under the action of a filter screen 710 of the filter 602, large-particle insoluble substances in the desulfurized ash water solution are blocked on the upper surface of the filter screen 710, so that the large-particle insoluble substances in the desulfurized ash can be removed, the rest part of the desulfurized ash water solution flows to the bottom of the filter 602 along holes in the filter screen 710, the desulfurized ash water solution flowing into the bottom of the filter 602 continues to flow to a filtering outlet 720 arranged at the bottom of the filter 602 under the action of gravity, and then flows into a suction filtration unit 601 arranged below the filtering outlet 720.
Further, after the desulfurized ash aqueous solution flows to the suction filtration device, the suction filtration unit 601 performs suction filtration on the desulfurized ash aqueous solution, a power supply of the circulating water vacuum pump 650 is firstly turned on, the desulfurized ash aqueous solution flows into the buchner funnel 610 under the action of gravity, the circulating water vacuum pump 650 is connected with the air suction port 620 arranged on one side of the vacuum air suction bottle 630 through the rubber hose 640, the desulfurized ash aqueous solution acting on the buchner funnel 610 through the rubber hose 640 starts vacuum pumping operation, pretreated desulfurized ash is obtained after vacuum filtration, large-particle insoluble substances in the desulfurized ash are screened out, the purity of the desulfurized ash is improved, the quality of calcium sulfate whiskers prepared by using the desulfurized ash is further improved, and then the pretreated desulfurized ash and MgCl are used for filtering the desulfurized ash2The solution is mixed and then transferred to a high-pressure reaction kettle 520 for hydro-thermal synthesis of calcium sulfate whiskers.
In the method for synthesizing calcium sulfate whiskers by using sintered flue gas desulfurization ash in one step, the reaction device includes an oxygen cylinder 510 and a high-pressure reaction kettle 520, the oxygen cylinder 510 is connected with an air inlet 523 at the top of the high-pressure reaction kettle 520 through a pipeline, an oxygen valve 528 is arranged on the air inlet 523, a pressure release valve 521 is arranged on the pipeline between the air inlet 523 and the high-pressure reaction kettle 520, a gas pressure gauge 522 is arranged on the high-pressure reaction kettle 520, and stirring blades 525 are arranged in the high-pressure reaction kettle 520. Adjusting the pH value of the slurry which is fully and uniformly stirred to be within 8-9, adding the slurry into the high-pressure reaction kettle 520, filling oxygen into the high-pressure reaction kettle 520 after the top cover of the high-pressure reaction kettle 520 is closed, controlling the stirring strength in the high-pressure reaction kettle 520 to be 400-flow 600r/min, and controlling the reaction time to be 2-3 h, and carrying out hydro-thermal synthesis to obtain the calcium sulfate whisker. The stirring intensity and the reaction time in the high-pressure reaction kettle 520 are controlled, so that the hydrothermal system has higher temperature and pressure, and the CaSO in the desulfurized fly ash can be promoted3·0.5H2Continuous dissolution of O and SO generated after dissolution3 2-Is oxidized into SO rapidly4 2-To make Ca in the solution2+、SO4 2-Is always in a supersaturated state, and simultaneously, the oxidation reaction is uninterruptedly carried out, thereby providing power for the crystallization and the growth of the calcium sulfate crystal whisker, realizing the synergistic preparation of the calcium sulfate crystal whisker by the oxidation of the sintering flue gas desulfurization ash, and further solving the problem of CaSO3Difficult rapid oxidation and long process flow of the preparation of the calcium sulfate whisker.
In this embodiment, the blowing air flow of the air inlet pipe 100 blows the desulfurized fly ash into the iron powder recovery cavity 200, the electromagnet generates magnetic force to adsorb the iron powder in the desulfurized fly ash onto the surface of the cotton sleeve 203, the cotton sleeve 203 improves the friction force between the surface of the electromagnet and the iron powder, and the iron powder adsorbed on the surface of the electromagnet is prevented from being blown off by the blowing air flow; the electromagnet comprises a lead 202 and an iron core 205, wherein the lead 202 is wound outside the iron core 205, the surface of the iron core 205 is provided with a vent hole 204, the vent hole 204 is communicated with the cylinder core of the iron core 205, and then the blowback gas tank 410 can convey blowback gas flow to the cylinder core of the iron core 205 through a gas pipeline; in addition, the diameter of the vent hole 204 is larger than that of the lead 202, so that when the lead 202 passes through the outer surface of the vent hole 204, the back-blowing airflow entering the iron core 205 can also flow out from gaps around the vent hole 204, and then is diffused to the outside through the cotton sleeve 203, and the back-blowing airflow diffused to the outside can prevent the desulfurized ash from entering the cotton sleeve 203 under the action of the blowing airflow, so that the effect of separating iron powder in the desulfurized ash is achieved.
The top cover 310 of the present embodiment is disposed on the top of the iron powder recovering chamber 200, and the filter layer 320 is disposed inside the top cover 310; the air inlet pipe 100 is arranged at the bottom of the iron powder recovery cavity 200, and the blowing air flow in the air inlet pipe 100 is used for blowing the desulfurization ash into the iron powder recovery cavity 200, so that the desulfurization ash enters the iron powder recovery cavity 200 through the air inlet pipe 100; the blowing air flow entering the iron powder collection cavity 200 from the air inlet pipe 100 flows out of the iron powder collection cavity 200 through the filter layer 320, so that the pressure intensity in the iron powder collection cavity 200 and the external pressure intensity are balanced, and the smooth separation process is ensured.
It should be noted that the electromagnets include a first electromagnet 210, a second electromagnet 220, and a third electromagnet 230, wherein the first electromagnet 210 and the second electromagnet 220 are arranged in parallel, a gap is provided between the first electromagnet 210 and the second electromagnet 220, the third electromagnet 230 is arranged on the upper portions of the first electromagnet 210 and the second electromagnet 220, and the third electromagnet 230 is arranged corresponding to the gap. The up-and-down arrangement mode of the electromagnets enables the electromagnets at different positions and different levels to be in full contact with the desulfurization ash, so that the electromagnets adsorb and recover the iron powder at different positions in the cavity 200, and further the separation efficiency of the iron powder in unit time is improved.
The third electromagnet 230 of the present embodiment includes a left electromagnet 231 and a right electromagnet 232, and a connection position of the left electromagnet 231 and the right electromagnet 232 is located right above the gap; the included angle of the left electromagnet 231 and the right electromagnet 232 is beta, the range of beta is 120-150 degrees, the beta value of the embodiment is 120 degrees, the adsorption area of the third electromagnet 230 on the iron powder is increased by the arrangement of the included angle beta, the electromagnetic acting force of the connection is enhanced, the third electromagnet 230 generates strong magnetic force to adsorb the iron powder in the desulfurization ash, and a good separation effect is achieved.
As shown in fig. 6 and 7, the top cover 310 is disposed on the top of the iron powder recovery cavity 200, an internal thread is disposed inside the top of the iron powder recovery cavity 200, and an external thread matched with the internal thread is disposed on the outer side wall of the top cover 310, so that the iron powder recovery cavity 200 and the top cover 310 are connected by a thread, and the installation efficiency can be improved by the thread connection; in addition, the filtering layer 320 is arranged inside the top cover 310, the filtering layer 320 is provided with a through hole, the through hole is matched with the power-on head 201, the power-on head 201 penetrates through the filtering layer 320 through the through hole, the power-on head 201 penetrates through the filtering layer 320 and extends to the outside of the top cover 310, and the power-on head 201 is electrically connected with a power supply. The filter layer 320 is a gauze, a filling layer with gaps or a dust removal cloth bag, gas can flow out through the filter layer 320 in the iron powder recovery process, and the filter layer 320 can limit the treated desulfurization ash in the iron powder recovery cavity 200, so that the treated desulfurization ash is concentrated in the iron powder recovery cavity 200, and the desulfurization ash is prevented from overflowing out of the iron powder recovery cavity 200 while the iron powder in the desulfurization ash is safely and efficiently separated.
Example 3
The basic contents of this embodiment are the same as embodiment 1, except that: the blowback gas tank 410 is connected with an air main pipe 420, the air main pipe 420 is connected with a first air branch pipe 421 and a second air branch pipe 422, the first air branch pipe 421 is communicated with two ends of the iron core 205 of the third electromagnet 230, and it is worth noting that: the first air flow branch pipe 421 is communicated with the cylinder core of the iron core 205, the cylinder core is a hollow channel, the cylinder core is communicated with the vent hole 204 on the surface of the iron core 205, and a sealing ring is arranged at the position where the first air flow branch pipe 421 is connected with the cylinder core, so that the leakage of the back-blowing air flow from the two ends of the cylinder core of the iron core 205 is avoided; the second airflow branch pipe 422 is respectively communicated with the iron cores 205 of the first electromagnet 210 and the second electromagnet 220, namely the second airflow branch pipe 422 is communicated with the cylinder core in the iron core 205, and a sealing ring is arranged at the connecting position of the second airflow branch pipe 422 and the cylinder core. The air inlet of the second air flow branch pipe 422 includes a left port connected to the left end of the core 205 of the first electromagnet 210 and a right port connected to the right end of the core 205 of the second electromagnet 220. The gas flow generated by the blowback gas tank 410 enters the first gas flow branch pipe 421 and the second gas flow branch pipe 422 through gas pipelines respectively; a first blowback valve 423 is arranged on the first air branch pipe 421, and a second blowback valve 424 is arranged on the second air branch pipe 422; the first blowback valve 423 is used for controlling the flow of the gas in the first branch 421, and the second blowback valve 424 is used for controlling the flow of the gas in the second branch 422. The first electromagnet 210 and the second electromagnet 220 are positioned close to the air inlet pipe 100, the power supply provides electric energy for the electromagnets through the electrifying head 201, and then the electromagnets generate magnetic force through electromagnetic induction, on one hand, because the probability that the first electromagnet 210 and the second electromagnet 220 at the positions are contacted with iron powder in the desulfurized ash is higher, the number of turns of the conducting wires 202 on the first electromagnet 210 and the second electromagnet 220 can be properly increased, and further the electromagnetic strength at the positions of the first electromagnet 210 and the second electromagnet 220 can be enhanced; on the other hand, the third electromagnet 230 is located farther from the air inlet duct 100 than the first electromagnet 210 and the second electromagnet 220, so that the probability of contact between the third electromagnet 230 and the iron powder in the desulfurized fly ash is lower, and the number of turns of the wire 202 on the third electromagnet 230 needs to be increased appropriately under the condition of the same current, so as to enhance the electromagnetic strength at the third electromagnet 230, thereby improving the adsorption of the third electromagnet 230 on the iron powder blown into the top end of the iron powder recovery cavity 200, further avoiding the situation that the iron powder adsorbed on the surface of the cotton sleeve 203 falls into the desulfurized fly ash again due to the blowback airflow, and reducing the separation purity of the desulfurized fly ash.
It should be noted that the desulfurized ash can permeate into the cotton sleeve 203 under the action of the blowing air flow of the air inlet pipe 100, so that the desulfurized ash is left in the cotton sleeve 203, the separation effect of the iron powder is poor, and at the moment, the air flow in the second air flow branch pipe 422 can be controlled by adjusting the second blowback valve 424, so that the blowback air flow flows from the inner surface to the outer surface of the cotton sleeve 203, and the desulfurized ash is prevented from being attached to the fiber holes of the cotton sleeve 203. Iron powder in the desulfurized fly ash is adsorbed on the surface of the cotton sleeve 203 under the action of electromagnetic force, and the desulfurized fly ash moving to the position near the electromagnet moves reversely to be far away from the cotton sleeve 203 under the action of the blowback air flow of the vent holes 204, so that the separation of the desulfurized fly ash and the iron powder is promoted, and the separation effect of the iron powder in the desulfurized fly ash is improved. The third electromagnet 230 is far away from the air inlet duct 100, and when the desulfurized ash moves to the vicinity of the third electromagnet 230, the gas impact on the desulfurized ash is smaller than that on the first electromagnet 210 and the second electromagnet 220, so in this embodiment, the gas flow in the first gas flow branch pipe 421 can be controlled by the first blowback valve 423, so that the gas flow in the first gas flow branch pipe 421 is smaller than that in the second gas flow branch pipe 422.
In addition, because the blowing air flow in the air inlet pipe 100 has a certain air pressure, the desulfurized ash can not enter the air inlet pipe 100 through the conveying pipe 102 by virtue of the self gravity, so that the embodiment is provided with a sealing cover at the top of the desulfurized ash groove 101, and the pressurized air tank 103 is connected with the desulfurized ash groove 101 through a pipeline; the pressurized gas tank 103 provides air pressure for the sealed desulfurization ash tank 101, so as to balance the air pressure in the air inlet pipe 100, so that the desulfurization ash is conveyed into the air inlet pipe 100 through the conveying pipe 102 under the action of the air pressure and the self gravity provided by the pressurized gas tank 103, the blowing air flow in the air inlet pipe 100 blows the desulfurization ash upwards into the iron powder recovery cavity 200 along the pipeline direction of the air inlet pipe 100, and then the iron powder in the desulfurization ash is separated in the iron powder recovery cavity 200.
Example 4
The basic content of this embodiment is the same as that of embodiment 1, as shown in fig. 8, except that: the air inlet pipe 100 comprises a first air inlet pipe 110 and a second air inlet pipe 120, the first air inlet pipe 110 and the second air inlet pipe 120 are arranged correspondingly, an included angle between the first air inlet pipe 110 and the second air inlet pipe 120 is a, the range of the a is 90-120 degrees, the first air inlet pipe 110 and the second air inlet pipe 120 can generate opposite blowing air flow at the bottom of the iron powder recovery cavity 200, so that the desulfurized ash is better dispersed, the desulfurized ash is blown to the top from the bottom of the iron powder recovery cavity 200 under the action of the blowing air flow, the desulfurized ash is prevented from falling down under the action of self gravity and being accumulated at the bottom of the iron powder recovery cavity 200, further, the full contact between the iron-containing desulfurized ash and the electromagnet is promoted, and the separation efficiency of the electromagnet on iron powder is improved.
Further, a desulfurization ash groove 101 is arranged on one side of the first air inlet pipe 110 far away from the second air inlet pipe 120; the bottom of the desulfurization ash tank 101 is connected with a first air inlet pipe 110 through a conveying pipe 102; a desulfurization ash groove 101 is formed in one side, away from the first air inlet pipe 110, of the second air inlet pipe 120; the bottom of the desulfurization ash tank 101 is connected with a second air inlet pipe 120 through a conveying pipe 102; the desulfurized ash in the desulfurized ash tank 101 is respectively added into the first air inlet pipe 110 and the second air inlet pipe 120 through the conveying pipe 102, so that the desulfurized ash is conveniently and directly added into the air inlet pipe 100 along the conveying pipe 102, the online separation of iron powder in the desulfurized ash is realized, and the actual production efficiency is improved. An end of the air inlet duct 100 remote from the fine iron recovery chamber 200 is provided with a blower fan 150, and the blower fan 150 is used to blow an air current into the air inlet duct 100. Since the air flow in the air inlet pipe 100 has a certain air pressure, when the air pressure is higher, the desulfurized ash cannot enter the air inlet pipe 100 from the desulfurized ash groove 101 along the conveying pipe 102 by virtue of its own gravity, so that the embodiment is provided with a sealing cover at the top of the desulfurized ash groove 101, and the pressurized air tank 103 is connected with the desulfurized ash groove 101 through a pipeline. The pressurized gas tank 103 provides air pressure to the sealed desulfurization ash tank 101, so as to balance the pressure of the air flow in the air inlet pipe 100, so that the desulfurization ash is conveyed into the air inlet pipe 100 through the conveying pipe 102 under the action of the air pressure and the self gravity provided by the pressurized gas tank 103, the air flow continuously blown into the air inlet pipe 100 blows the desulfurization ash upwards into the iron powder recovery cavity 200 along the pipeline direction of the air inlet pipe 100, and the iron powder in the desulfurization ash is separated in the iron powder recovery cavity 200.
Meanwhile, a cavity contracting section 240 is arranged at the bottom of the iron powder recovering cavity 200, and the air inlet pipe 100 is connected with the bottom of the cavity contracting section 240; the air inlet pipe 100 is connected with the bottom of the iron powder recovery cavity 200 through a cavity contraction section 240, an air pipe joint 130 is arranged between the first air inlet pipe 110 and the second air inlet pipe 120, the air pipe joint 130 is arranged corresponding to a gap between the first electromagnet 210 and the second electromagnet 220, and the air pipe joint 130 extends into the cavity contraction section 240 to a position higher than the bottom of the cavity contraction section 240. The direction upward movement of the jetting air current that air-supply line 100 produced respectively along first air-supply line 110 and second air-supply line 120, the jetting air current is gathered and is got into cavity constriction section 240 at tuber pipe junction 130, the bottom shrink design of cavity constriction section 240, make the jetting air current gather up upward movement, thereby the relative gathering of the jetting air current of air-supply line 100 insufflations at cavity constriction section 240, be favorable to the desulfurization ash to blow to the top by the bottom of iron powder recovery cavity 200 under the effect of jetting air current, avoid the desulfurization ash to deposit in iron powder recovery cavity 200 bottom because of the atress inequality falls under the effect of self gravity, and then lead to the separation effect of desulfurization ash relatively poor. The conveying pipe 102 is provided with a material valve 104, and the material valve 104 can be opened or closed according to requirements; the bottom side walls of the first and second air inlet ducts 110 and 120 are connected to a blower fan 150 through a duct provided with a blower valve for controlling the flow rate of gas in the duct; a recycling groove 140 is provided right below the bottoms of the first and second air inlet ducts 110 and 120, and the recycling groove 140 is used for collecting the desulfurized fly ash after the separation of the iron powder.
As shown in fig. 9, the upper end of the cavity contracting section 240 is connected to the bottom of the iron powder recovery cavity 200 through the corrugated pipe 131, the lower end of the cavity contracting section 240 is connected to the top of the air inlet pipe 100 through the corrugated pipe 131, and the cavity contracting section 240 is provided with a vibration mechanism for driving the cavity contracting section 240 to vibrate, so that the desulfurization ash accumulated on the cavity contracting section 240 falls to the recovery tank 140 through the first air inlet pipe 110 and the second air inlet pipe 120, thereby facilitating the sufficient collection of the desulfurization ash of the separated iron powder, and improving the yield of calcium sulfate whiskers prepared from the desulfurization ash.
The invention has been described in detail hereinabove with reference to specific exemplary embodiments thereof. It will, however, be understood that various modifications and changes may be made without departing from the scope of the invention as defined in the appended claims. The detailed description and drawings are to be regarded as illustrative rather than restrictive, and any such modifications and variations are intended to be included within the scope of the present invention as described herein. Furthermore, the background is intended to be illustrative of the state of the art as developed and the meaning of the present technology and is not intended to limit the scope of the invention or the application and field of application of the invention.
Claims (7)
1. A method for synthesizing calcium sulfate whiskers by using sintered flue gas desulfurization ash in one step is characterized by comprising the following steps:
the method comprises the following steps: pretreatment of desulfurized fly ash
Adding the desulfurized ash into a desulfurized ash iron powder separation device to separate iron powder, blowing the desulfurized ash into an iron powder recovery cavity (200) by blowing air flow generated by an air inlet pipe (100) of the desulfurized ash iron powder separation device, and adsorbing the iron powder in the desulfurized ash on the surface of a cotton sleeve (203) by generating magnetic force by an electromagnet; after the blowing air flow of the air inlet pipe (100) is closed, the desulfurized ash after the iron powder is separated falls into the recovery tank (140) under the action of gravity; taking the desulfurized ash from the recovery tank (140), mixing the desulfurized ash with water, screening out large-particle insoluble substances in the desulfurized ash, and carrying out vacuum filtration on the desulfurized ash from which the large-particle insoluble substances are screened out to obtain pretreated desulfurized ash;
step two: preparation of calcium sulfate whisker
(1) MgCl with a concentration of 2% is prepared2The solution acts as a habit modifier to MgCl2Adding the solution into the pretreated desulfurized ash, and uniformly stirring to obtain slurry, wherein the solid-to-liquid ratio of the slurry is controlled to be 1/15-1/20;
(2) to the slurry was added dropwise saturated Ca (OH)2Adjusting the pH of the slurry to 8-9;
(3) adding the slurry into a high-pressure reaction kettle (520), closing a top cover of the high-pressure reaction kettle (520), then filling oxygen into the high-pressure reaction kettle (520), and stirring the slurry in the high-pressure reaction kettle (520), wherein the stirring strength is 400-600r/min, and the reaction time is 2-3 h, so that the calcium sulfate whisker is hydrothermally synthesized in the high-pressure reaction kettle (520).
2. The method for synthesizing the calcium sulfate whiskers by the one-step method by using the sintered flue gas desulfurization ash as claimed in claim 1, is characterized in that: reaction unit includes oxygen cylinder (510) and high pressure batch autoclave (520), and oxygen cylinder (510) link to each other through air inlet (523) at pipeline and high pressure batch autoclave (520) top, are provided with oxygen valve (528) on air inlet (523), are provided with relief valve (521) on the pipeline between air inlet (523) and high pressure batch autoclave (520), be provided with barometer (522) on high pressure batch autoclave (520), be provided with stirring vane (525) in high pressure batch autoclave (520).
3. The method for synthesizing the calcium sulfate whiskers by the one-step method by using the sintered flue gas desulfurization ash as claimed in claim 1, is characterized in that: the method comprises the following steps: the method comprises the following specific steps of desulfurization ash pretreatment:
(1) adding desulfurized ash into a desulfurized ash and iron powder separating device of an iron powder recovery device, starting an electromagnet, simultaneously opening an air valve of a back-blowing air tank (410), making back-blowing air in the back-blowing air tank (410) flow into a cylinder core of an electromagnet iron core (205) through a pipeline, and then making back-blowing air flow overflow from an air hole (204) on the surface of the iron core (205) to the outside of the electromagnet;
(2) starting a blast fan (150), and spraying blowing air flow generated by the blast fan (150) into the iron powder recovery cavity (200) from bottom to top through an air inlet pipe (100);
(3) conveying the desulfurized ash into an air inlet pipe (100) through a desulfurized ash groove (101);
(4) the desulfurization ash is blown into the iron powder recovery cavity (200) by blowing airflow of the air inlet pipe (100), and the iron powder in the desulfurization ash is adsorbed on the surface of the cotton sleeve (203);
(5) closing the blowing air flow of the air inlet pipe (100), and dropping the desulfurized ash after separating the iron powder into the recovery tank (140) under the action of gravity;
(6) and (3) taking the desulfurized ash from which the iron powder is removed out of the recovery tank (140), mixing the desulfurized ash with water, screening out large-particle insoluble substances, and placing the desulfurized ash from which the large-particle insoluble substances are screened out in a suction filtration device for vacuum filtration to obtain the pretreated desulfurized ash.
4. The method for synthesizing calcium sulfate whiskers by using the sintered flue gas desulfurization ash in one step according to claim 3, is characterized in that: in the first step (1), the blowback air flow in the blowback air tank (410) enters the first air flow branch pipe (421) and the second air flow branch pipe (422) through the main air flow pipe (420), and the flow rates of the first blowback valve (423) and the second blowback valve (424) are controlled simultaneously.
5. The method for synthesizing calcium sulfate whiskers by using the sintered flue gas desulfurization ash in one step according to claim 3, is characterized in that: in the step one (3), the desulfurization ash is added into the desulfurization ash tank (101), an air valve of a pressurization air tank (103) is started, the pressurization air tank (103) pressurizes the desulfurization ash tank (101), then a material valve (104) is opened, and the desulfurization ash in the desulfurization ash tank (101) is conveyed into an air inlet pipe (100) through a conveying pipe (102).
6. The method for synthesizing calcium sulfate whiskers by using the sintered flue gas desulfurization ash in one step according to claim 3, is characterized in that: in the step one (4), the desulfurization ash is sprayed into the iron powder recovery cavity (200) by the blowing air flow of the air inlet pipe (100), the desulfurization ash is sprayed to the periphery of the electromagnet under the action of the blowing air flow, the iron powder in the desulfurization ash is adsorbed on the surface of the cotton sleeve (203) by the electromagnet, and meanwhile, the back blowing air flow overflows outwards through the vent holes (204) on the surface of the electromagnet iron core (205) so as to prevent the desulfurization ash from permeating into the cotton sleeve (203).
7. The method for synthesizing calcium sulfate whiskers by using the sintered flue gas desulfurization ash in one step according to any one of claims 3 to 6, wherein the method comprises the following steps: the iron powder recovery device desulfurization ash iron powder separation device comprises an air inlet pipe (100), an iron powder recovery cavity (200), a top cover (310) and a back-blowing air tank (410); an electromagnet and a cotton sleeve (203) are arranged in the iron powder recovery cavity (200), the cotton sleeve (203) wraps the outside of the electromagnet, the electromagnet comprises a lead (202) and an iron core (205), the lead (202) is wound on the outside of the iron core (205), a vent hole (204) is formed in the surface of the iron core (205), and the vent hole (204) is communicated with the cylinder center of the iron core (205); the top cover (310) is arranged at the top of the iron powder recovery cavity (200), and a filter layer (320) is arranged inside the top cover (310); the air inlet pipe (100) is arranged at the bottom of the iron powder recovery cavity (200), and the desulfurized ash enters the iron powder recovery cavity (200) through the air inlet pipe (100); the back blowing air tank (410) is connected with the cylinder core of the iron core (205) through an air pipeline, and the bottom of the air inlet pipe (100) is provided with a recovery tank (140).
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| EP1633486A1 (en) * | 2003-06-09 | 2006-03-15 | Dow Corning Corporation | Magnetic separator apparatus |
| CN201791675U (en) * | 2010-09-21 | 2011-04-13 | 山东泓奥电力科技有限公司 | High-field intensity magnetic separation coal-desulfurization device |
| CN102002756B (en) * | 2010-11-16 | 2013-03-20 | 东北大学 | Method of preparing calcium sulfate whisker by using sinter fume desulfurized by-products |
| CN102351232A (en) * | 2011-07-07 | 2012-02-15 | 浙江大学 | Process for removing ferrosilicon particles in carbide slag slurry |
| CN102912445A (en) * | 2012-10-22 | 2013-02-06 | 浙江天蓝环保技术股份有限公司 | Process and device for preparing gypsum whisker by semi-dry desulfurized fly ash and waste acid |
| CN105540635B (en) * | 2016-02-04 | 2017-01-25 | 江苏永钢集团有限公司 | Treatment device for semi-dry desulfurized fly ash |
| CN106757363B (en) * | 2016-11-29 | 2019-05-07 | 安徽工业大学 | A method of calcium sulfate crystal whiskers are prepared using sintering flue gas desulfurization by-product |
| CN107400929B (en) * | 2017-03-03 | 2019-07-09 | 安徽工业大学 | A method of the sintering flue gas semi-dry desulphurization ash based on acid oxidation prepares calcium sulfate crystal whiskers |
| CN106698979A (en) * | 2017-03-14 | 2017-05-24 | 江苏沙钢集团有限公司 | Sintering desulfurization ash treatment system and method |
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2018
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