CN112794701A - Alpha alumina with low sodium oxide content and preparation method thereof - Google Patents
Alpha alumina with low sodium oxide content and preparation method thereof Download PDFInfo
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- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical compound [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 title claims abstract description 62
- KKCBUQHMOMHUOY-UHFFFAOYSA-N sodium oxide Chemical compound [O-2].[Na+].[Na+] KKCBUQHMOMHUOY-UHFFFAOYSA-N 0.000 title claims abstract description 53
- 229910001948 sodium oxide Inorganic materials 0.000 title claims abstract description 51
- 238000002360 preparation method Methods 0.000 title abstract description 16
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 162
- 239000011734 sodium Substances 0.000 claims abstract description 60
- 239000000377 silicon dioxide Substances 0.000 claims abstract description 58
- 229910052708 sodium Inorganic materials 0.000 claims abstract description 52
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 claims abstract description 49
- 238000000034 method Methods 0.000 claims abstract description 38
- 239000006004 Quartz sand Substances 0.000 claims abstract description 36
- 238000001354 calcination Methods 0.000 claims abstract description 27
- 238000006243 chemical reaction Methods 0.000 claims abstract description 21
- 239000000463 material Substances 0.000 claims abstract description 14
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 12
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 12
- 239000010703 silicon Substances 0.000 claims abstract description 12
- 235000012239 silicon dioxide Nutrition 0.000 claims abstract description 6
- 238000002156 mixing Methods 0.000 claims abstract description 4
- 239000004576 sand Substances 0.000 claims description 8
- 239000002994 raw material Substances 0.000 claims description 7
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonia chloride Chemical compound [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 claims description 6
- TWRXJAOTZQYOKJ-UHFFFAOYSA-L Magnesium chloride Chemical compound [Mg+2].[Cl-].[Cl-] TWRXJAOTZQYOKJ-UHFFFAOYSA-L 0.000 claims description 6
- IRPGOXJVTQTAAN-UHFFFAOYSA-N 2,2,3,3,3-pentafluoropropanal Chemical compound FC(F)(F)C(F)(F)C=O IRPGOXJVTQTAAN-UHFFFAOYSA-N 0.000 claims description 3
- KLZUFWVZNOTSEM-UHFFFAOYSA-K Aluminum fluoride Inorganic materials F[Al](F)F KLZUFWVZNOTSEM-UHFFFAOYSA-K 0.000 claims description 3
- 235000019270 ammonium chloride Nutrition 0.000 claims description 3
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 claims description 3
- 239000004327 boric acid Substances 0.000 claims description 3
- 229910001629 magnesium chloride Inorganic materials 0.000 claims description 3
- 238000007873 sieving Methods 0.000 claims description 3
- 238000012216 screening Methods 0.000 abstract description 8
- 239000012535 impurity Substances 0.000 abstract description 7
- 229910052911 sodium silicate Inorganic materials 0.000 abstract description 6
- 239000007787 solid Substances 0.000 abstract description 5
- KEAYESYHFKHZAL-UHFFFAOYSA-N Sodium Chemical compound [Na] KEAYESYHFKHZAL-UHFFFAOYSA-N 0.000 abstract description 2
- 229940024545 aluminum hydroxide Drugs 0.000 description 20
- 239000000047 product Substances 0.000 description 15
- 230000000052 comparative effect Effects 0.000 description 14
- 239000003795 chemical substances by application Substances 0.000 description 8
- 230000008569 process Effects 0.000 description 8
- 239000000126 substance Substances 0.000 description 7
- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Chemical compound [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 description 6
- 230000009471 action Effects 0.000 description 5
- 239000013078 crystal Substances 0.000 description 5
- 238000012986 modification Methods 0.000 description 5
- 230000004048 modification Effects 0.000 description 5
- 239000000919 ceramic Substances 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 229910020489 SiO3 Inorganic materials 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 3
- NDLPOXTZKUMGOV-UHFFFAOYSA-N oxo(oxoferriooxy)iron hydrate Chemical compound O.O=[Fe]O[Fe]=O NDLPOXTZKUMGOV-UHFFFAOYSA-N 0.000 description 3
- 229910052814 silicon oxide Inorganic materials 0.000 description 3
- 239000004115 Sodium Silicate Substances 0.000 description 2
- 229910052681 coesite Inorganic materials 0.000 description 2
- 229910052593 corundum Inorganic materials 0.000 description 2
- 229910052906 cristobalite Inorganic materials 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 2
- 238000001179 sorption measurement Methods 0.000 description 2
- 229910052682 stishovite Inorganic materials 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 229910052905 tridymite Inorganic materials 0.000 description 2
- 229910001845 yogo sapphire Inorganic materials 0.000 description 2
- 238000004131 Bayer process Methods 0.000 description 1
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 1
- PZPMSRKHFDCMAC-UHFFFAOYSA-M [OH-].[Na+].[O-2].[Al+3] Chemical compound [OH-].[Na+].[O-2].[Al+3] PZPMSRKHFDCMAC-UHFFFAOYSA-M 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 150000004645 aluminates Chemical class 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- ANBBXQWFNXMHLD-UHFFFAOYSA-N aluminum;sodium;oxygen(2-) Chemical compound [O-2].[O-2].[Na+].[Al+3] ANBBXQWFNXMHLD-UHFFFAOYSA-N 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 229910001388 sodium aluminate Inorganic materials 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
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- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
- C04B35/10—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on aluminium oxide
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- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
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- C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
- C04B2235/3205—Alkaline earth oxides or oxide forming salts thereof, e.g. beryllium oxide
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- C04B2235/3217—Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
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Abstract
The invention discloses alpha alumina with low sodium oxide content and a preparation method thereof, wherein the preparation method comprises the following steps: uniformly mixing 100 parts by weight of high-sodium aluminum hydroxide, 1-3 parts by weight of silica-containing quartz sand and 0.62-0.775 part by weight of mineralizer, and calcining to obtain a reaction material; the mass fraction of silicon dioxide in the silicon-containing quartz sand is more than or equal to 96 percent; the reaction mass is sieved to obtain alpha alumina with low sodium oxide content. According to the invention, SiO in the silica-containing quartz sand is added after the silica-containing quartz sand is calcined2+ NaO reaction to Na2SiO3Sodium is adsorbed on the surface of silica-containing quartz sand in a solid form, impurities are screened out by using a screening method, the aim of reducing the sodium content of calcined alpha alumina is fulfilled, and the mass fraction of the sodium oxide in the finally prepared alpha alumina with low sodium oxide content is less than or equal to 0.3%.
Description
Technical Field
The invention relates to the technical field of preparation of high-purity substances, in particular to alpha alumina with low sodium oxide content and a preparation method thereof.
Background
The calcined alpha alumina series products are used as industrial ceramic raw materials, are widely applied to industries such as wear-resistant ceramics, ceramic glaze materials, refractory materials and the like, and particularly, with the gradual improvement of the quality requirements of industrial ceramics, customers put forward higher requirements on the quality of calcined alpha alumina. The low-sodium calcined alpha-alumina has wide market prospect, but the product is influenced by the sodium hydroxide-aluminum oxide for a long time, so that the coarse grain size cannot meet the use requirement of customers. Sodium is considered to be one of main impurities in the production processes for preparing alumina by a Bayer process, a sintering process, a combination process and the like, and is one of important indexes for grade evaluation of high-purity alumina. The sodium content of the alumina is mainly determined by the sodium in the aluminum hydroxide. There are three main forms of sodium in aluminum hydroxide: sodium is adsorbed on the surface of aluminum hydroxide and sodium wrapped by crystal, sodium replaces hydrogen atoms in aluminum hydroxide to be mixed in intercrystalline sodium during decomposing and crystallizing process of aluminate, and crystalline sodium is Na formed during decomposing and crystallizing process of aluminate2O—Al2O3—CO2—H2O-based compound and Na2O—Al2O3—SiO2—H2An O-series compound. Sodium entrained in aluminum hydroxide hydrate forms high sodium aluminate (xNa) during sintering2O·yAl2O3) Reduce alpha-AL2O3The conversion rate and activity of the alumina, and further influences the physical and chemical properties of the sintered product alumina. Therefore, the removal of sodium from aluminum hydroxide has become a process for preparing high-purity aluminum oxideAnd (5) important links.
Therefore, how to develop an alpha alumina with low sodium oxide content and a preparation method thereof become a key technical problem for research of metallurgists.
Disclosure of Invention
The invention aims to provide alpha alumina with low sodium oxide content and a preparation method thereof.
In order to achieve the above object, the present invention provides a method for preparing alpha alumina having a low sodium oxide content, the method comprising:
uniformly mixing 100 parts by weight of high-sodium aluminum hydroxide, 1-3 parts by weight of silica-containing quartz sand and 0.62-0.775 part by weight of mineralizer, and calcining to obtain a reaction material; wherein the mass fraction of silicon dioxide in the silicon-containing quartz sand is more than or equal to 96 percent;
the reaction mass is sieved to obtain alpha alumina with low sodium oxide content.
Further, the mass fraction of sodium element in the high-sodium aluminum hydroxide is 0.25-0.35%.
Further, the calcination temperature is 1350-1450 ℃, and the calcination time is 45-60 min.
Further, the weight part of the mineralizer is 0.7 part.
Further, the mineralizer is at least one of boric acid, aluminum fluoride, ammonium chloride and magnesium chloride.
Further, the mass fraction of silica in the silica-containing silica sand is 98%.
Further, the silicon-containing quartz sand is 2 parts by weight.
Further, a 30-50-mesh sieve is adopted in the screening.
The invention also provides alpha alumina with low sodium oxide content, and the raw materials for preparing the alpha alumina with low sodium oxide content comprise: 100 parts of high-sodium aluminum hydroxide, 1-3 parts of silica-containing quartz sand and 0.62-0.775 part of mineralizer.
Further, the mass fraction of the sodium oxide in the alpha alumina with low sodium oxide content is less than or equal to 0.3 percent.
One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:
the invention provides alpha alumina with low sodium oxide content and a preparation method thereof, wherein 100 parts by weight of high-sodium aluminum hydroxide, 1-3 parts by weight of silica-containing quartz sand and 0.62-0.775 part by weight of mineralizer are uniformly mixed and then calcined to obtain a reaction material; the mass fraction of silicon dioxide in the silicon-containing quartz sand is more than or equal to 96 percent; sieving the reaction material to obtain alpha alumina with low sodium oxide content; breaks through the original method that sodium is discharged from the kiln tail in the form of steam under the high-temperature action of the rotary kiln, and SiO in silica-containing quartz sand is added after the silica-containing quartz sand is calcined2+ NaO reaction to Na2SiO3Sodium is adsorbed on the surface of silica-containing quartz sand in a solid form, and impurities are screened out by using a screening method, so that the aim of reducing the sodium content of the calcined alpha alumina is fulfilled. The method can better meet the requirements of customers on various physical and chemical indexes such as the grain size, sodium oxide, conversion rate and the like of the product. The mass fraction of the sodium oxide in the finally prepared alpha alumina with low sodium oxide content is less than or equal to 0.3 percent.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.
Fig. 1 is a flow chart of a method for preparing alpha alumina with low sodium oxide content according to an embodiment of the present invention.
Detailed Description
The present invention will be described in detail below with reference to specific embodiments and examples, and the advantages and various effects of the present invention will be more clearly apparent therefrom. It will be understood by those skilled in the art that these specific embodiments and examples are for the purpose of illustrating the invention and are not to be construed as limiting the invention.
Throughout the specification, unless otherwise specifically noted, terms used herein should be understood in accordance with the meanings commonly used in the art. Accordingly, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. If there is a conflict, the present specification will control.
Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.
In order to solve the technical problems, the embodiment of the invention provides the following general ideas:
according to an exemplary embodiment of the present invention, there is provided a method for preparing alpha alumina having a low sodium oxide content, as shown in fig. 1, the method comprising:
s1, uniformly mixing 100 parts by weight of high-sodium aluminum hydroxide, 1-3 parts by weight of silica-containing quartz sand and 0.62-0.775 part by weight of mineralizer, and calcining to obtain a reaction material; the mass fraction of silicon dioxide in the silicon-containing quartz sand is more than or equal to 96 percent;
s2, screening the reaction material to obtain alpha alumina with low sodium oxide content.
According to the preparation method of the alpha alumina with low sodium oxide content provided by the embodiment of the invention, the original method that sodium is discharged from the kiln tail in a steam form under the high-temperature action of the rotary kiln is broken through, after the silica-containing quartz sand is added for calcination, the sodium is adsorbed on the surface of the silica-containing quartz sand in a solid form, and impurities are screened out by using a screening method, so that the purpose of reducing the sodium content of the calcined alpha alumina is realized. The method can better meet the requirements of customers on various physical and chemical indexes such as the grain size, sodium oxide, conversion rate and the like of the product. The mass fraction of the sodium oxide in the finally prepared alpha alumina with low sodium oxide content is less than or equal to 0.3 percent.
In the original method of discharging sodium from the tail of a rotary kiln in a steam form under the high-temperature action of the rotary kiln, volatile compounds can release harmful gases such as fluoride and the like in the process, pollute the environment and cause the working condition to be poor. And the mass fraction of sodium oxide in the finally prepared alpha alumina is higher and is more than 0.3 percent.
SiO in silica-containing silica sand in the embodiment of the invention2+ NaO reaction to Na2SiO3Has sodium removing effect, and Na generated after calcination2SiO3The pore size is large, sodium-containing solids can be greatly adsorbed, and the sodium silicate for adsorbing sodium is a sodium-containing sample obtained after screening.
The technical scheme provided by the embodiment of the invention has the advantages of simple process, small investment and easy implementation and operation, and reduces the content of the calcined alpha alumina sodium oxide produced by using high-sodium aluminum hydroxide as a raw material to be less than or equal to 0.3 percent by combining the actual production of the calcined alpha alumina.
In the present embodiment, the first and second embodiments are described,
the silicon-containing quartz sand accounts for 1-3 parts: the embodiment of the invention discovers for the first time that the silica-containing quartz sand is used as the sodium removal agent, the sodium removal effect of the silica-containing quartz sand is obvious under the auxiliary action of the mineralizer, the influence on the product quality caused by the easy screening of the silica-containing sodium removal agent after sodium removal is small, and the silica-containing sodium removal agent can get rid of the dependence on raw materials in the early stage in the production process to produce high-end products; if the silicon-containing quartz sand is added too little, the sodium removal rate is not improved, and if the silicon-containing quartz sand is added too much, excessive Si impurities are introduced.
The mineralizer accounts for 0.62-0.775 parts: the mineralizer has the functions of reducing the calcination temperature of the product during actual calcination and playing a role of a catalyst on one hand, and improving the grain size of the calcined alpha alumina product, perfecting the crystal structure and achieving the target requirement on the other hand. Too little addition is difficult to do; too much addition and too large grain size increase affect subsequent use performance; the mineralizer is at least one of boric acid, aluminum fluoride, ammonium chloride and magnesium chloride.
The reason why the mass fraction of the silicon dioxide in the silicon-containing quartz sand is more than or equal to 96% is as follows: SiO in silica-containing quartz sand2+ NaO reaction to Na2SiO3(ii) a Na produced2SiO3Namely the sodium silicate for adsorbing sodium. If the silicon content is too low, the sodium removal rate is not improved; if the silicon content is too high, too much Si impurities may be introduced.
Preferably, the calcining temperature is 1350-1450 ℃, and the calcining time is 45-60 min; if the calcination temperature is too high, the calcined alpha alumina is over-burnt, the product index is deviated, and the fuel waste caused by the use of customers cannot be met; if the calcination temperature is too low, the calcination degree of the material is insufficient, and the product quality fluctuates.
In a preferred embodiment, a 30-50 mesh sieve is used for the sieving. The reason for this is that: the sodium removing agent after sodium oxide adsorption is screened out in time, so that the content purity of aluminum oxide in the material is ensured, and the service performance of customers is ensured.
The method for preparing alpha alumina having a low sodium oxide content according to the present application will be described in detail with reference to examples, comparative examples and experimental data.
Example 1
The embodiment provides alpha alumina with low sodium oxide content and a preparation method thereof, and the preparation method comprises the following specific operations:
100 parts of high-sodium aluminum hydroxide, 2 parts of high-efficiency sodium removing agent and 0.7 part of mineralizer are conveyed into a high-temperature kiln through a feeding screw to be calcined, the inlet temperature of a primary cyclone is gradually increased to 450 ℃ from 410 ℃, the kiln speed is controlled to be 28hz, the calcining time is 0.75 hour, the calcined material enters a cooler to be forcibly cooled to be below 80 ℃, and then the calcined material is discharged out of the cooler to be conveyed and lifted by a lifting device to be put into a bin and packaged. After calcination, the primary crystal calcined alpha alumina product with 0.3 percent of sodium oxide, 0.1 percent of silicon oxide, 0.02 percent of ferric oxide, 93 percent of conversion rate and 2.8 mu m of grain size is obtained.
Example 2
The embodiment provides alpha alumina with low sodium oxide content and a preparation method thereof, and the preparation method comprises the following specific operations:
100 parts of high-sodium aluminum hydroxide, 1 part of high-efficiency sodium removing agent and 0.62 part of mineralizer are conveyed into a high-temperature kiln through a feeding screw to be calcined, the inlet temperature of a primary cyclone is gradually increased to 440 ℃ from 410 ℃, the kiln speed is controlled to be 26hz, the calcining time is 0.8 hour, and the calcined material enters a cooler to be forcibly cooled to below 80 ℃, then is discharged out of the cooler, conveyed through a lifting device, conveyed into a bin and packaged. After calcination, the primary crystal calcined alpha alumina product with the sodium oxide content of 0.25 percent, the silicon oxide content of 0.1 percent, the ferric oxide content of 0.02 percent, the conversion rate of 93 percent and the grain size of 2.5 mu m is obtained.
Example 3
The embodiment provides alpha alumina with low sodium oxide content and a preparation method thereof, and the preparation method comprises the following specific operations:
100 parts of high-sodium aluminum hydroxide, 3 parts of high-efficiency sodium removing agent and 0.775 part of mineralizer are conveyed into a high-temperature kiln through a feeding screw to be calcined, the inlet temperature of a primary cyclone is gradually increased to 440 ℃ from 410 ℃, the kiln speed is controlled to be 26hz, the calcining time is 0.8 hour, and the calcined material enters a cooler to be forcibly cooled to below 80 ℃, then is discharged out of the cooler, conveyed through a lifting device, conveyed into a bin and packaged. After calcination, the primary crystal calcined alpha alumina product with the sodium oxide content of 0.25 percent, the silicon oxide content of 0.1 percent, the ferric oxide content of 0.02 percent, the conversion rate of 93 percent and the grain size of 2.5 mu m is obtained.
Comparative example 1
In this comparative example, 100 parts of high-sodium aluminum hydroxide and 0.5 part of silica-containing silica sand were used, and the other steps were the same as in example 1.
Comparative example 2
In this comparative example, 100 parts of high-sodium aluminum hydroxide and 5 parts of silica-containing silica sand were used, and the other steps were the same as in example 1.
Comparative example 3
In this comparative example, the silica content of the silica-containing silica sand was 90% by mass, and the rest of the procedure was the same as in example 1.
Experimental example 1
The results of the evaluation of the low sodium oxide content alpha alumina of each example and comparative example are shown in table 1.
TABLE 1
| Sample coding | Al2O3％ | Fe2O3％ | Na2O％ | SiO2％ | αAl2O3％ | Grain size, μm | Effective density | Reduced by ignition |
| Example 1 | 99.67 | 0.008 | 0.218 | 0.069 | 94.2 | 2.29 | 3.94 | 0.04 |
| Example 2 | 99.59 | 0.008 | 0.282 | 0.068 | 94.2 | 2.91 | 3.94 | 0.05 |
| Example 3 | 99.66 | 0.01 | 0.232 | 0.059 | 94.8 | 3.17 | 3.95 | 0.04 |
| Comparative example 1 | 99.29 | 0.008 | 0.661 | 0.014 | 90.4 | 3.16 | 3.90 | 0.03 |
| Comparative example 2 | 99.26 | 0.008 | 0.624 | 0.012 | 88.1 | 3.41 | 3.88 | 0.1 |
| Comparative example 3 | 99.28 | 0.008 | 0.599 | 0.016 | 91.9 | 3.21 | 3.92 | 0.1 |
As can be seen from the data in Table 1:
in comparative example 1, the addition amount of the silica-containing quartz sand is 0.5% of that of the high-sodium aluminum hydroxide and is less than the range of 2-3% of the invention, the sodium removal rate of the prepared calcined alumina is low, and Na is contained2The content of O is as high as 0.661 percent;
in comparative example 2, the addition amount of the silica-containing quartz sand is 5% of that of the high-sodium aluminum hydroxide and is larger than the range of 2-3% of the invention, and the calcined alumina prepared has low sodium removal rate and Na content2The content of O is as high as 0.624%;
in comparative example 3, the mass fraction of silica in the silica-containing silica sand is 90% and is less than the range of Si of the invention which is more than or equal to 96%, and the calcined alumina prepared by the method has low sodium removal rate and Na2The content of O is as high as 0.599 percent.
In the embodiments 1 to 3, 1 to 3 parts of silica-containing quartz sand is added to 100 parts of high-sodium aluminum hydroxide, the mass fraction of silica in the silica-containing quartz sand is not less than 96%, and after calcination, sodium is adsorbed on the surface of the silica-containing quartz sand in a solid form and impurities are screened out by using a screening method, so that the purpose of reducing sodium in the calcined alpha-alumina is achieved.
Application example 1
The method provided by the embodiment of the invention is adopted for sodium removal, the chemical components of the silica-containing quartz sand before sodium removal are shown in table 2, and the chemical components of the sodium-containing sample obtained after sodium removal of the high-sodium aluminum hydroxide are shown in table 2; na formed after calcination2SiO3The adsorption conditions of (2) are shown in Table 3.
TABLE 2 chemical composition of Quartz Sand before and after calcination of Industrial expansion test
| SiO2 | Al2O3 | Na2O | Fe2O3 | |
| Silica-containing quartz sand | 98.58％ | 0.91％ | 0.036％ | ＜0.01％ |
| Sodium-containing sample | 18.28％ | 73.35％ | 5.34％ | ＜0.01％ |
TABLE 3 Industrial expansion test for alumina loss
Note: total Na2The O content is 0.31% of AH raw material
As can be seen from the data in tables 2 to 3: the silica-containing quartz sand of the embodiment of the invention has obvious sodium removal effect after calcination under the auxiliary action of the mineralizer, the silica-containing sodium removal agent after sodium removal is easy to screen out and has little influence on the product quality, and the method better meets the requirements of customers on various physicochemical indexes of the product such as the grain size, sodium oxide, conversion rate and the like. The mass fraction of the sodium oxide in the finally prepared alpha alumina with low sodium oxide content is less than or equal to 0.3 percent.
Finally, it should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (10)
1. A method for preparing alpha alumina with low sodium oxide content, which is characterized by comprising the following steps:
uniformly mixing 100 parts by weight of high-sodium aluminum hydroxide, 1-3 parts by weight of silica-containing quartz sand and 0.62-0.775 part by weight of mineralizer, and calcining to obtain a reaction material; wherein the mass fraction of silicon dioxide in the silicon-containing quartz sand is more than or equal to 96 percent;
the reaction mass is sieved to obtain alpha alumina with low sodium oxide content.
2. The method for preparing alpha alumina with low sodium oxide content according to claim 1, wherein the mass fraction of sodium element in the high-sodium aluminum hydroxide is 0.25-0.35%.
3. The method for preparing alpha alumina with low sodium oxide content according to claim 1, wherein the calcination temperature is 1350-1450 ℃, and the calcination time is 45-60 min.
4. The method of claim 1, wherein the mineralizer is present in an amount of 0.7 parts by weight.
5. The method of claim 1, wherein the mineralizer is at least one of boric acid, aluminum fluoride, ammonium chloride, and magnesium chloride.
6. The method of claim 1, wherein the silica-containing silica sand comprises silica in an amount of 98% by mass.
7. The method of claim 1, wherein the silica-containing silica sand is present in an amount of 2 parts by weight.
8. The method for preparing alpha alumina with low sodium oxide content according to claim 1, wherein a 30-50 mesh sieve is adopted in the sieving.
9. The alpha alumina with low sodium oxide content is characterized in that the raw materials for preparing the alpha alumina with low sodium oxide content comprise: 100 parts of high-sodium aluminum hydroxide, 1-3 parts of silica-containing quartz sand and 0.62-0.775 part of mineralizer.
10. The low sodium oxide alpha alumina of claim 9, wherein the low sodium oxide alpha alumina has a mass fraction of sodium oxide of 0.3% or less.
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| CN114408955A (en) * | 2022-01-10 | 2022-04-29 | 中铝山东有限公司 | Alpha-alumina for ceramic ball and preparation method thereof |
| CN114455619A (en) * | 2022-01-12 | 2022-05-10 | 中铝山东新材料有限公司 | Low-sodium small primary crystal alpha alumina and preparation method thereof |
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| CN108190930A (en) * | 2017-12-11 | 2018-06-22 | 湖北斯曼新材料有限公司 | A kind of preparation method of suboxides sodium impurity content alpha-phase aluminum oxide |
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| CN114408955A (en) * | 2022-01-10 | 2022-04-29 | 中铝山东有限公司 | Alpha-alumina for ceramic ball and preparation method thereof |
| CN114455619A (en) * | 2022-01-12 | 2022-05-10 | 中铝山东新材料有限公司 | Low-sodium small primary crystal alpha alumina and preparation method thereof |
| CN114455619B (en) * | 2022-01-12 | 2024-05-07 | 中铝山东新材料有限公司 | Low-sodium small primary crystal alpha alumina and preparation method thereof |
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