CN117534039A - Method for efficiently preparing aluminum nitride by using fly ash - Google Patents
Method for efficiently preparing aluminum nitride by using fly ash Download PDFInfo
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- CN117534039A CN117534039A CN202311659746.9A CN202311659746A CN117534039A CN 117534039 A CN117534039 A CN 117534039A CN 202311659746 A CN202311659746 A CN 202311659746A CN 117534039 A CN117534039 A CN 117534039A
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- 238000000034 method Methods 0.000 title claims abstract description 64
- 239000010881 fly ash Substances 0.000 title claims abstract description 32
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 title claims abstract description 31
- VSCWAEJMTAWNJL-UHFFFAOYSA-K aluminium trichloride Chemical compound Cl[Al](Cl)Cl VSCWAEJMTAWNJL-UHFFFAOYSA-K 0.000 claims abstract description 58
- FDNAPBUWERUEDA-UHFFFAOYSA-N silicon tetrachloride Chemical compound Cl[Si](Cl)(Cl)Cl FDNAPBUWERUEDA-UHFFFAOYSA-N 0.000 claims abstract description 32
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims abstract description 29
- 238000005121 nitriding Methods 0.000 claims abstract description 29
- 239000012071 phase Substances 0.000 claims abstract description 26
- 238000005660 chlorination reaction Methods 0.000 claims abstract description 19
- 239000007790 solid phase Substances 0.000 claims abstract description 19
- 239000002245 particle Substances 0.000 claims abstract description 17
- 238000006243 chemical reaction Methods 0.000 claims abstract description 15
- 238000009833 condensation Methods 0.000 claims abstract description 13
- 230000005494 condensation Effects 0.000 claims abstract description 13
- 229910021578 Iron(III) chloride Inorganic materials 0.000 claims abstract description 8
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 claims abstract description 8
- 239000000843 powder Substances 0.000 claims abstract description 7
- 238000000926 separation method Methods 0.000 claims abstract description 4
- 238000000746 purification Methods 0.000 claims abstract description 3
- 238000001816 cooling Methods 0.000 claims description 27
- 238000002485 combustion reaction Methods 0.000 claims description 22
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical class [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims description 21
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 11
- 239000007789 gas Substances 0.000 claims description 10
- 239000002893 slag Substances 0.000 claims description 10
- 229910021529 ammonia Inorganic materials 0.000 claims description 9
- 239000000428 dust Substances 0.000 claims description 9
- 239000000779 smoke Substances 0.000 claims description 9
- 239000003546 flue gas Substances 0.000 claims description 8
- 229910052710 silicon Inorganic materials 0.000 claims description 7
- 239000010703 silicon Substances 0.000 claims description 7
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonia chloride Chemical compound [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 claims description 6
- 239000002956 ash Substances 0.000 claims description 6
- 239000000446 fuel Substances 0.000 claims description 6
- 235000019270 ammonium chloride Nutrition 0.000 claims description 3
- 239000007791 liquid phase Substances 0.000 claims description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 abstract description 8
- 229910052782 aluminium Inorganic materials 0.000 abstract description 8
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 abstract description 4
- 229910052799 carbon Inorganic materials 0.000 abstract description 4
- 238000009825 accumulation Methods 0.000 abstract description 3
- 230000006911 nucleation Effects 0.000 abstract description 3
- 238000010899 nucleation Methods 0.000 abstract description 3
- 239000012320 chlorinating reagent Substances 0.000 abstract description 2
- 238000005243 fluidization Methods 0.000 abstract description 2
- 238000005453 pelletization Methods 0.000 abstract description 2
- 238000002360 preparation method Methods 0.000 abstract description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 abstract 2
- TWRXJAOTZQYOKJ-UHFFFAOYSA-L Magnesium chloride Chemical compound [Mg+2].[Cl-].[Cl-] TWRXJAOTZQYOKJ-UHFFFAOYSA-L 0.000 abstract 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 abstract 1
- 229910052742 iron Inorganic materials 0.000 abstract 1
- 229910052749 magnesium Inorganic materials 0.000 abstract 1
- 239000011777 magnesium Substances 0.000 abstract 1
- 229910001629 magnesium chloride Inorganic materials 0.000 abstract 1
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 8
- 238000005245 sintering Methods 0.000 description 8
- 235000019738 Limestone Nutrition 0.000 description 5
- 239000002253 acid Substances 0.000 description 5
- 239000006028 limestone Substances 0.000 description 5
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 4
- 239000000377 silicon dioxide Substances 0.000 description 4
- 235000012239 silicon dioxide Nutrition 0.000 description 4
- 229910000029 sodium carbonate Inorganic materials 0.000 description 4
- 235000012241 calcium silicate Nutrition 0.000 description 3
- 229910052918 calcium silicate Inorganic materials 0.000 description 3
- JHLNERQLKQQLRZ-UHFFFAOYSA-N calcium silicate Chemical compound [Ca+2].[Ca+2].[O-][Si]([O-])([O-])[O-] JHLNERQLKQQLRZ-UHFFFAOYSA-N 0.000 description 2
- XFWJKVMFIVXPKK-UHFFFAOYSA-N calcium;oxido(oxo)alumane Chemical compound [Ca+2].[O-][Al]=O.[O-][Al]=O XFWJKVMFIVXPKK-UHFFFAOYSA-N 0.000 description 2
- 239000003245 coal Substances 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 239000003344 environmental pollutant Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 231100000719 pollutant Toxicity 0.000 description 2
- 239000002910 solid waste Substances 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- 238000004131 Bayer process Methods 0.000 description 1
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 238000003915 air pollution Methods 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- CSDREXVUYHZDNP-UHFFFAOYSA-N alumanylidynesilicon Chemical compound [Al].[Si] CSDREXVUYHZDNP-UHFFFAOYSA-N 0.000 description 1
- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 description 1
- DIZPMCHEQGEION-UHFFFAOYSA-H aluminium sulfate (anhydrous) Chemical compound [Al+3].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O DIZPMCHEQGEION-UHFFFAOYSA-H 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 239000000378 calcium silicate Substances 0.000 description 1
- OYACROKNLOSFPA-UHFFFAOYSA-N calcium;dioxido(oxo)silane Chemical compound [Ca+2].[O-][Si]([O-])=O OYACROKNLOSFPA-UHFFFAOYSA-N 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000002386 leaching Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000009856 non-ferrous metallurgy Methods 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-N sulfuric acid Substances OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 1
- 239000002918 waste heat Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B21/00—Nitrogen; Compounds thereof
- C01B21/06—Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron
- C01B21/072—Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron with aluminium
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Treating Waste Gases (AREA)
Abstract
The invention discloses a method for efficiently preparing aluminum nitride by utilizing fly ash, which adopts silicon chloride to chloridize aluminum, iron and magnesium in the fly ash into aluminum chloride, ferric chloride and magnesium chloride, and obtains high-purity aluminum chloride through multistage condensation, separation and purification, and the aluminum chloride is gasified, preheated and reacted with ammonia gas to generate an aluminum nitride product. The invention uses silicon chloride as chlorinating agent of chlorination reaction, does not need carbon matching and pelletizing, has simple operation, and is easy to separate and purify the product. The fluidized bed is adopted as a chlorination reactor, so that the mass transfer and heat transfer rate between the gas phase and the solid phase is high, and the reaction efficiency is high. The arrangement of inert large particles in the chlorination reactor can obviously improve fluidization quality and play a role in heat accumulation. The seed powder is added into the nitriding reactor, so that nucleation sites and matrixes can be provided, the nitriding reaction is promoted, the product is convenient to collect, meanwhile, the system energy utilization rate is high, the large-scale and high-efficiency preparation of aluminum nitride from the fly ash can be realized, and good economic and social benefits are achieved.
Description
Technical Field
The invention relates to the field of chemical nonferrous metallurgy environmental protection, in particular to a method for efficiently preparing aluminum nitride by utilizing fly ash.
Background
Fly ash is solid waste generated by coal combustion, 1t of fly ash is generated when 4t of coal is consumed, and the yield is huge. The fly ash has finer granularity, is easy to cause regional air pollution, and can pollute soil and water after long-term storage. The fly ash contains abundant aluminum resources, and aluminum extraction is an important direction of high-value utilization.
The method for extracting aluminum from fly ash mainly comprises an alkaline method and an acid method, wherein the alkaline method mainly comprises a limestone sintering method and a sodium carbonate sintering method. The limestone sintering method is to add a certain amount of limestone in the fly ash sintering process, activate and bake the fly ash to generate calcium aluminate and dicalcium silicate at 1200-1400 ℃, realize silicon-aluminum separation by utilizing the solubility difference of the calcium aluminate and dicalcium silicate in sodium carbonate solution, and obtain alumina through dissolution, desilication, carbon content and calcination. The limestone sintering method has been industrially produced, however, the method has higher energy consumption and more complex process, and simultaneously, 1 ton of alumina is produced to produce 8-10 tons of new solid waste calcium silicate slag, and the secondary pollutant discharge amount is larger. The sodium carbonate sintering process is to activate and bake flyash at 700-900 deg.c to produce acid soluble silicate, and to separate silicon from aluminum through acid or alkali leaching to obtain alumina with high purity. Compared with the limestone sintering method, the sodium carbonate sintering method has less waste residue discharge, however, the method has longer process flow, is only suitable for the fly ash with the mass fraction of alumina higher than 30 percent, and is difficult to popularize and apply on a large scale.
The acid method is to bake the fly ash by using concentrated sulfuric acid, dissolve out the baked product, separate solid and liquid, crystallize to obtain aluminum sulfate, and then calcine, dissolve out by Bayer process, seed divide, calcine the aluminum hydroxide to obtain metallurgical grade aluminum oxide. The acid method has complicated process flow, higher equipment cost, larger amount of waste liquid generated in the impurity removal process, easy secondary pollution and difficult industrial application.
Therefore, aiming at the current situation that the current technology cannot efficiently utilize aluminum resources in the fly ash, the processing process is enhanced through technological and technical innovation, the reaction efficiency is improved, the process energy consumption is reduced, and the preparation of high-added-value products by utilizing the aluminum resources in the fly ash is a key point for realizing large-scale efficient clean high-value utilization of the fly ash.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide a method for efficiently preparing aluminum nitride by utilizing fly ash.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
a method for efficiently preparing aluminum nitride by using fly ash comprises the following steps:
s1, preheating I: preheating the fly ash to obtain hot ash;
s2, chlorination: carrying out chlorination reaction on high-temperature silicon chloride and the hot ash obtained in the step S1 to obtain high-temperature chlorinated flue gas and chlorinated slag, wherein the high-temperature chlorinated flue gas is sent to a preheating I process of the step S1 and is used for preheating the fly ash through heat exchange, and the low-temperature chlorinated flue gas after heat exchange is sent to a multistage condensation process of the step S6;
s3, gasifying I: gasifying liquid-phase silicon chloride to obtain gas-phase silicon chloride, and conveying the gas-phase silicon chloride into a heat exchange cooling step I of the step S4;
s4, heat exchange and cooling I: performing heat exchange and cooling on the chloridized slag obtained in the step S2 by utilizing gas-phase chloridized silicon to obtain hot chloridized silicon and tailings;
s5, combustion preheating I: preheating the hot silicon chloride obtained in the step S4 by utilizing the combustion of air and fuel to obtain high-temperature silicon chloride and combustion tail gas I, and sending the high-temperature silicon chloride into a chlorination process of the step S2;
s6, multistage condensation: carrying out multistage condensation separation and purification on low-temperature chlorinated flue gas to respectively obtain solid-phase aluminum chloride, solid-phase ferric chloride and gas-phase circulating silicon chloride, and sending the circulating silicon chloride into a heat exchange cooling I process in the step S4 for cooling the chlorinated slag through heat exchange;
s7, gasifying II: gasifying the solid-phase aluminum chloride obtained in the step S6 to obtain gas-phase aluminum chloride;
s8, preheating II: preheating the gas-phase aluminum chloride obtained in the step S7 to obtain hot aluminum chloride;
s9, nitriding: nitriding reaction is carried out by utilizing high Wen Anqi and the hot aluminum chloride obtained in the step S8 to obtain hot aluminum nitride and high-temperature nitriding smoke, the high-temperature nitriding smoke is sent to a preheating I I process of the step S8 and is used for preheating gas-phase aluminum chloride through heat exchange, and the low-temperature nitriding smoke after heat exchange is sent to a condensation dust collection process of the step S11;
s10, heat exchange and cooling II: cooling the hot aluminum nitride obtained in the step S9 by utilizing ammonia through heat exchange to obtain an aluminum nitride product and hot ammonia, and sending the hot ammonia into a combustion preheating step II of the step S12;
s11, condensing and collecting dust: condensing and dust collecting the low-temperature nitriding flue gas to obtain circulating ammonia gas and ammonium chloride, and sending the circulating ammonia gas into a heat exchange cooling II procedure of the step S10 for cooling the hot aluminum nitride through heat exchange;
s12, combustion preheating II: the hot ammonia gas obtained in the step S10 is preheated by the combustion of air and fuel to obtain high Wen Anqi and combustion tail gas II, and the high Wen Anqi is sent to the nitriding process in the step S9.
Further, in step S1, the particle size of the fly ash is less than 1 μm.
Further, in the step S2, the temperature of the chlorination reaction is 700-900 ℃ and the time is 0.5-1h, the adopted reactor is a fluidized bed reactor, inert oxide is arranged in the fluidized bed reactor, the inert oxide is spherical silicon dioxide particles, and the granularity of the spherical silicon dioxide particles is 0.5-3mm.
In step S6, the low-temperature chloridizing flue gas is condensed to 200-290 ℃ to obtain solid-phase ferric chloride, then the flue gas is further condensed to 70-170 ℃ to obtain solid-phase aluminum chloride, and the rest gas phase is the gas-phase circulating silicon chloride.
Further, in step S9, the nitriding reaction is carried out at a temperature of 700-900 ℃ for 0.5-1h, the adopted reactor is a fluidized bed reactor, seed powder is arranged in the fluidized bed reactor, and the seed powder is aluminum nitride particles with a granularity of 0.1-0.5 mm.
Further, in step S11, the condensation temperature is 20-200 ℃.
The invention has the beneficial effects that:
1. according to the invention, silicon chloride is used as a chlorinating agent for the chlorination reaction, carbon matching and pelletizing are not needed, the operation is simple and convenient, no carbon emission is generated in the chlorination process, and the chlorinated product is easy to separate and purify;
2. the invention adopts the fluidized bed provided with the inert large-particle oxide for chloridizing reaction, the inert large-particle oxide can inhibit fine particle agglomeration, break bubbles, strengthen mass transfer and heat transfer between gas and solid phases, and simultaneously can play a role in heat accumulation, thereby effectively improving the high reaction efficiency and the stability of system operation;
3. according to the invention, ammonia gas is utilized to react with aluminum chloride in a fluidized bed to prepare aluminum nitride, seed powder is added to provide nucleation sites and matrixes for newly generated aluminum nitride, so that the nitridation reaction is promoted, the product purity is high, and the collection is convenient;
4. the invention has high waste heat recovery and utilization rate, and effectively improves the heat efficiency of the whole process system;
5. the invention can efficiently convert the aluminum resource in the fly ash into aluminum nitride with high added value, has no secondary pollutant discharge, and has remarkable economic and social benefits.
Drawings
FIG. 1 is a flow chart of a method according to various embodiments of the present invention.
Detailed Description
The present invention will be further described with reference to the accompanying drawings, and it should be noted that, while the present embodiment provides a detailed implementation and a specific operation process on the premise of the present technical solution, the protection scope of the present invention is not limited to the present embodiment.
Example 1
The embodiment provides a method for efficiently preparing aluminum nitride by using fly ash, which is shown in fig. 1 and comprises the following steps:
s1, preheating I: preheating fly ash with the particle size smaller than 1 mu m to obtain hot ash;
s2, chlorination: carrying out chlorination reaction on high-temperature silicon chloride and the hot ash obtained in the step S1 to obtain high-temperature chlorinated flue gas and chlorinated slag, wherein the high-temperature chlorinated flue gas is sent to a preheating I process of the step S1 and is used for preheating the fly ash through heat exchange, and the low-temperature chlorinated flue gas after heat exchange is sent to a multistage condensation process of the step S6; the temperature of the chlorination reaction is 700 ℃ and the time is 1h; the reactor adopts a fluidized bed reactor, and spherical silica particles with the granularity of 0.5mm are arranged in the fluidized bed reactor and are used for assisting fluidization and heat accumulation;
s3, gasifying I: gasifying liquid-phase silicon chloride to obtain gas-phase silicon chloride, and conveying the gas-phase silicon chloride into a heat exchange cooling step I of the step S4;
s4, heat exchange and cooling I: performing heat exchange and cooling on the chloridized slag obtained in the step S2 by utilizing gas-phase chloridized silicon to obtain hot chloridized silicon and tailings;
s5, combustion preheating I: preheating the hot silicon chloride obtained in the step S4 by utilizing the combustion of air and fuel to obtain high-temperature silicon chloride and combustion tail gas I, and sending the high-temperature silicon chloride into a chlorination process of the step S2;
s6, multistage condensation: condensing the low-temperature chlorinated flue gas to 200 ℃ to obtain solid-phase ferric chloride, further condensing to 70 ℃ to obtain solid-phase aluminum chloride, wherein the remaining gas phase is circulating silicon chloride, and the circulating silicon chloride is sent to a heat exchange cooling step I of the step S4 and used for cooling the chlorinated slag through heat exchange;
s7, gasifying II: gasifying the solid-phase aluminum chloride obtained in the step S6 to obtain gas-phase aluminum chloride;
s8, preheating II: preheating the gas-phase aluminum chloride obtained in the step S7 to obtain hot aluminum chloride;
s9, nitriding: nitriding reaction is carried out by utilizing high Wen Anqi and the hot aluminum chloride obtained in the step S8 to obtain hot aluminum nitride and high-temperature nitriding smoke, the high-temperature nitriding smoke is sent to a preheating I I process of the step S8 and is used for preheating gas-phase aluminum chloride through heat exchange, and the low-temperature nitriding smoke after heat exchange is sent to a condensation dust collection process of the step S11; the temperature of the nitriding reaction is 700 ℃ and the time is 1h, the reactor is a fluidized bed reactor, and aluminum nitride particles with the granularity of 0.1mm are arranged in the fluidized bed reactor as seed powder for providing nucleation sites and matrixes for newly-generated aluminum nitride to promote the nitriding reaction;
s10, heat exchange and cooling II: cooling the hot aluminum nitride obtained in the step S9 by utilizing ammonia through heat exchange to obtain an aluminum nitride product and hot ammonia, and sending the hot ammonia into a combustion preheating step II of the step S12;
s11, condensing and collecting dust: condensing and dust collecting the low-temperature nitriding flue gas, wherein the condensing temperature is 20 ℃, circulating ammonia gas and ammonium chloride are obtained, and the circulating ammonia gas is sent into a heat exchange cooling II procedure of the step S10 and is used for cooling hot aluminum nitride through heat exchange;
s12, combustion preheating II: the hot ammonia gas obtained in the step S10 is preheated by the combustion of air and fuel to obtain high Wen Anqi and combustion tail gas II, and the high Wen Anqi is sent to the nitriding process in the step S9.
Example 2
The process flow of this example is substantially the same as example 1, except that: in the step S2, the temperature of the chlorination reaction is 900 ℃, the time is 0.5h, and the granularity of the spherical silicon dioxide particles is 3mm; in the step S6, the low-temperature chloridizing flue gas is firstly condensed to 290 ℃ to obtain solid-phase ferric chloride, and then further condensed to 170 ℃ to obtain solid-phase aluminum chloride; in the step S9, the temperature of the nitriding reaction is 900 ℃, the time is 0.5h, and the granularity of the aluminum nitride particles is 0.5mm; in step S11, the condensing temperature is 200 ℃.
Example 3
The process flow of this example is substantially the same as example 1, except that: in the step S2, the temperature of the chlorination reaction is 800 ℃, the time is 0.8h, and the granularity of the spherical silicon dioxide particles is 2mm; in the step S6, the low-temperature chloridizing flue gas is firstly condensed to 240 ℃ to obtain solid-phase ferric chloride, and then further condensed to 130 ℃ to obtain solid-phase aluminum chloride; in the step S9, the temperature of the nitriding reaction is 800 ℃, the time is 0.7h, and the granularity of the aluminum nitride particles is 0.3mm; in step S11, the condensing temperature is 100 ℃.
Various modifications and variations of the present invention will be apparent to those skilled in the art in light of the foregoing teachings and are intended to be included within the scope of the following claims.
Claims (6)
1. The method for efficiently preparing the aluminum nitride by using the fly ash is characterized by comprising the following steps of:
s1, preheating I: preheating the fly ash to obtain hot ash;
s2, chlorination: carrying out chlorination reaction on high-temperature silicon chloride and the hot ash obtained in the step S1 to obtain high-temperature chlorinated flue gas and chlorinated slag, wherein the high-temperature chlorinated flue gas is sent to a preheating I process of the step S1 and is used for preheating the fly ash through heat exchange, and the low-temperature chlorinated flue gas after heat exchange is sent to a multistage condensation process of the step S6;
s3, gasifying I: gasifying liquid-phase silicon chloride to obtain gas-phase silicon chloride, and conveying the gas-phase silicon chloride into a heat exchange cooling step I of the step S4;
s4, heat exchange and cooling I: performing heat exchange and cooling on the chloridized slag obtained in the step S2 by utilizing gas-phase chloridized silicon to obtain hot chloridized silicon and tailings;
s5, combustion preheating I: preheating the hot silicon chloride obtained in the step S4 by utilizing the combustion of air and fuel to obtain high-temperature silicon chloride and combustion tail gas I, and sending the high-temperature silicon chloride into a chlorination process of the step S2;
s6, multistage condensation: carrying out multistage condensation separation and purification on low-temperature chlorinated flue gas to respectively obtain solid-phase aluminum chloride, solid-phase ferric chloride and gas-phase circulating silicon chloride, and sending the circulating silicon chloride into a heat exchange cooling I process in the step S4 for cooling the chlorinated slag through heat exchange;
s7, gasifying II: gasifying the solid-phase aluminum chloride obtained in the step S6 to obtain gas-phase aluminum chloride;
s8, preheating II: preheating the gas-phase aluminum chloride obtained in the step S7 to obtain hot aluminum chloride;
s9, nitriding: nitriding reaction is carried out by utilizing high Wen Anqi and the hot aluminum chloride obtained in the step S8 to obtain hot aluminum nitride and high-temperature nitriding smoke, the high-temperature nitriding smoke is sent to a preheating II process of the step S8 and is used for preheating gas-phase aluminum chloride through heat exchange, and the low-temperature nitriding smoke after heat exchange is sent to a condensation dust collection process of the step S11;
s10, heat exchange and cooling II: cooling the hot aluminum nitride obtained in the step S9 by utilizing ammonia through heat exchange to obtain an aluminum nitride product and hot ammonia, and sending the hot ammonia into a combustion preheating step II of the step S12;
s11, condensing and collecting dust: condensing and dust collecting the low-temperature nitriding flue gas to obtain circulating ammonia gas and ammonium chloride, and sending the circulating ammonia gas into a heat exchange cooling II procedure of the step S10 for cooling the hot aluminum nitride through heat exchange;
s12, combustion preheating II: the hot ammonia gas obtained in the step S10 is preheated by the combustion of air and fuel to obtain high Wen Anqi and combustion tail gas II, and the high Wen Anqi is sent to the nitriding process in the step S9.
2. The method according to claim 1, wherein in step S1, the fly ash has a particle size of less than 1 μm.
3. The method according to claim 1, wherein in step S2, the chlorination reaction is carried out at a temperature of 700-900 ℃ for a time of 0.5-1h, the reactor is a fluidized bed reactor, inert oxide is provided in the fluidized bed reactor, the inert oxide is spherical silica particles, and the particle size of the spherical silica particles is 0.5-3mm.
4. The method according to claim 1, wherein in step S6, the low-temperature chlorinated flue gas is first condensed to 200-290 ℃ to obtain solid-phase ferric chloride, and then the flue gas is further condensed to 70-170 ℃ to obtain solid-phase aluminum chloride, and the remaining gas phase is the gas-phase recycled silicon chloride.
5. The method according to claim 1, wherein in step S9, the nitriding reaction is performed at a temperature of 700-900 ℃ for 0.5-1h, the reactor is a fluidized bed reactor, seed powder is arranged in the fluidized bed reactor, and the seed powder is aluminum nitride particles with a particle size of 0.1-0.5 mm.
6. The method according to claim 1, wherein in step S11, the condensing temperature is 20-200 ℃.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311659746.9A CN117534039A (en) | 2023-12-06 | 2023-12-06 | Method for efficiently preparing aluminum nitride by using fly ash |
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