CN115124072A - Method for preparing high-purity nano titanium dioxide by sulfuric acid process and product - Google Patents
Method for preparing high-purity nano titanium dioxide by sulfuric acid process and product Download PDFInfo
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- CN115124072A CN115124072A CN202210846668.2A CN202210846668A CN115124072A CN 115124072 A CN115124072 A CN 115124072A CN 202210846668 A CN202210846668 A CN 202210846668A CN 115124072 A CN115124072 A CN 115124072A
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- titanium dioxide
- sulfuric acid
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- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 title claims abstract description 87
- 238000000034 method Methods 0.000 title claims abstract description 62
- SOQBVABWOPYFQZ-UHFFFAOYSA-N oxygen(2-);titanium(4+) Chemical compound [O-2].[O-2].[Ti+4] SOQBVABWOPYFQZ-UHFFFAOYSA-N 0.000 title claims abstract description 37
- 230000008569 process Effects 0.000 title claims abstract description 14
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims abstract description 150
- 239000004408 titanium dioxide Substances 0.000 claims abstract description 74
- 229910000349 titanium oxysulfate Inorganic materials 0.000 claims abstract description 53
- 230000007062 hydrolysis Effects 0.000 claims abstract description 44
- 238000006460 hydrolysis reaction Methods 0.000 claims abstract description 44
- 239000002253 acid Substances 0.000 claims abstract description 41
- 239000000843 powder Substances 0.000 claims abstract description 31
- 239000002270 dispersing agent Substances 0.000 claims abstract description 25
- 239000002002 slurry Substances 0.000 claims abstract description 25
- 238000001354 calcination Methods 0.000 claims abstract description 20
- 238000001914 filtration Methods 0.000 claims abstract description 18
- 238000005406 washing Methods 0.000 claims abstract description 18
- 230000032683 aging Effects 0.000 claims abstract description 16
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 claims abstract description 15
- 229910052921 ammonium sulfate Inorganic materials 0.000 claims abstract description 15
- 235000011130 ammonium sulphate Nutrition 0.000 claims abstract description 15
- 238000003756 stirring Methods 0.000 claims abstract description 14
- 238000001035 drying Methods 0.000 claims abstract description 7
- 238000007865 diluting Methods 0.000 claims abstract 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 14
- 150000003863 ammonium salts Chemical class 0.000 claims description 9
- -1 polyoxyethylene lauryl ether Polymers 0.000 claims description 8
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 claims description 6
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 claims description 6
- 235000011114 ammonium hydroxide Nutrition 0.000 claims description 6
- 239000007822 coupling agent Substances 0.000 claims description 5
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 claims description 4
- 239000004721 Polyphenylene oxide Substances 0.000 claims description 4
- 229920002125 Sokalan® Polymers 0.000 claims description 4
- WGCNASOHLSPBMP-UHFFFAOYSA-N hydroxyacetaldehyde Natural products OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 claims description 4
- 239000004584 polyacrylic acid Substances 0.000 claims description 4
- 229920000570 polyether Polymers 0.000 claims description 4
- 229920005862 polyol Polymers 0.000 claims description 4
- 150000003077 polyols Chemical group 0.000 claims description 4
- 229920000056 polyoxyethylene ether Polymers 0.000 claims description 4
- 229940051841 polyoxyethylene ether Drugs 0.000 claims description 4
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 claims description 2
- 229920000259 polyoxyethylene lauryl ether Polymers 0.000 claims description 2
- 229920000036 polyvinylpyrrolidone Polymers 0.000 claims description 2
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 claims description 2
- 239000001267 polyvinylpyrrolidone Substances 0.000 claims description 2
- 239000002245 particle Substances 0.000 abstract description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 22
- 239000008367 deionised water Substances 0.000 description 13
- 229910021641 deionized water Inorganic materials 0.000 description 13
- 239000010936 titanium Substances 0.000 description 12
- 229910052719 titanium Inorganic materials 0.000 description 12
- 238000001816 cooling Methods 0.000 description 11
- 238000010438 heat treatment Methods 0.000 description 11
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 10
- 238000006243 chemical reaction Methods 0.000 description 10
- 239000012071 phase Substances 0.000 description 8
- 239000007789 gas Substances 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 6
- 239000007791 liquid phase Substances 0.000 description 6
- 239000000047 product Substances 0.000 description 6
- 239000013078 crystal Substances 0.000 description 5
- 239000012535 impurity Substances 0.000 description 5
- 229910052742 iron Inorganic materials 0.000 description 5
- 238000002360 preparation method Methods 0.000 description 5
- 238000004846 x-ray emission Methods 0.000 description 4
- 229910010413 TiO 2 Inorganic materials 0.000 description 3
- 238000005054 agglomeration Methods 0.000 description 3
- 230000002776 aggregation Effects 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 3
- 230000001276 controlling effect Effects 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 238000000746 purification Methods 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 2
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 2
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 2
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000004061 bleaching Methods 0.000 description 2
- 239000003990 capacitor Substances 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- LQZZUXJYWNFBMV-UHFFFAOYSA-N dodecan-1-ol Chemical compound CCCCCCCCCCCCO LQZZUXJYWNFBMV-UHFFFAOYSA-N 0.000 description 2
- 229910001448 ferrous ion Inorganic materials 0.000 description 2
- 235000003891 ferrous sulphate Nutrition 0.000 description 2
- 239000011790 ferrous sulphate Substances 0.000 description 2
- 230000003301 hydrolyzing effect Effects 0.000 description 2
- 238000005216 hydrothermal crystallization Methods 0.000 description 2
- 238000001027 hydrothermal synthesis Methods 0.000 description 2
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 2
- 229910000359 iron(II) sulfate Inorganic materials 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 229910052749 magnesium Inorganic materials 0.000 description 2
- 239000011777 magnesium Substances 0.000 description 2
- 229910052758 niobium Inorganic materials 0.000 description 2
- 239000010955 niobium Substances 0.000 description 2
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 2
- 229910052698 phosphorus Inorganic materials 0.000 description 2
- 239000011574 phosphorus Substances 0.000 description 2
- 238000004537 pulping Methods 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 238000001878 scanning electron micrograph Methods 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 229910052726 zirconium Inorganic materials 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- JLVVSXFLKOJNIY-UHFFFAOYSA-N Magnesium ion Chemical compound [Mg+2] JLVVSXFLKOJNIY-UHFFFAOYSA-N 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- 239000006096 absorbing agent Substances 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000012065 filter cake Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 239000012761 high-performance material Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
- 229910001425 magnesium ion Inorganic materials 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 238000000593 microemulsion method Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 239000002086 nanomaterial Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 239000000123 paper Substances 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 229920000058 polyacrylate Polymers 0.000 description 1
- 229920005646 polycarboxylate Polymers 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000003980 solgel method Methods 0.000 description 1
- VEALVRVVWBQVSL-UHFFFAOYSA-N strontium titanate Chemical compound [Sr+2].[O-][Ti]([O-])=O VEALVRVVWBQVSL-UHFFFAOYSA-N 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G23/00—Compounds of titanium
- C01G23/04—Oxides; Hydroxides
- C01G23/047—Titanium dioxide
- C01G23/053—Producing by wet processes, e.g. hydrolysing titanium salts
- C01G23/0532—Producing by wet processes, e.g. hydrolysing titanium salts by hydrolysing sulfate-containing salts
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y40/00—Manufacture or treatment of nanostructures
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- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G23/00—Compounds of titanium
- C01G23/008—Titanium- and titanyl sulfate
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/30—Particle morphology extending in three dimensions
- C01P2004/32—Spheres
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/60—Particles characterised by their size
- C01P2004/64—Nanometer sized, i.e. from 1-100 nanometer
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
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Abstract
The invention discloses a method for preparing high-purity nano titanium dioxide by a sulfuric acid process, which comprises the following steps: (1) carrying out acidolysis on metatitanic acid powder by using concentrated sulfuric acid to obtain acidolysis solution, and diluting the acidolysis solution to obtain titanyl sulfate solution; the concentration of the titanyl sulfate solution is 30-500g/L based on the mass of the titanium dioxide; (2) slowly adding the titanyl sulfate solution into the organic dispersant solution for hydrolysis at the hydrolysis temperature of 30-90 ℃ for 2-12 h, and then preserving heat and aging to obtain titanium dioxide slurry; (3) filtering and washing titanium dioxide slurry, adjusting the pH value to 8-10, stirring and aging for 2-5 hours, adding ammonium sulfate, filtering and drying to obtain powder; (4) and (4) calcining the powder prepared in the step (3) at 400-700 ℃ to prepare the high-purity nano titanium dioxide. The purity of the nano titanium dioxide prepared by the method is high and reaches more than 99.9 percent, the particle size is easy to control, and the sphericity is better.
Description
Technical Field
The invention belongs to the technical field of nano material preparation, and particularly relates to a method for preparing high-purity nano titanium dioxide by a sulfuric acid method and a product.
Background
Because of its unique physical and chemical properties and excellent optical properties, titanium dioxide is widely used in many fields such as paint, plastics, paper making, rubber, capacitor, etc. Meanwhile, because the titanium dioxide has high dielectric constant and resistivity and has semiconductor characteristics, the titanium dioxide becomes a basic raw material for preparing other high-performance materials, for example, the titanium dioxide can be used for preparing catalyst carriers, ultraviolet absorbers, special glass, electronic ceramics, thermistors, semiconductor capacitors, strontium titanate piezoresistors, functionalized titanium dioxide, titanium metal and the like. In recent years, the demand of the market for titanium dioxide keeps growing at a high speed, and in many high-end manufacturing fields, such as the fields of liquid crystal material preparation, precision sensors, aerospace coatings and the like, the quality requirement of titanium dioxide is extremely strict, particularly the content requirement of impurities such as iron and the like, so that higher requirements are provided for the preparation of high-purity titanium dioxide.
At present, the preparation method of the nano titanium dioxide mainly comprises a gas phase method and a liquid phase method. The gas phase process comprises TiCl 4 Gas phase hydrogen flame hydrolysis, TiCl 4 The gas phase oxidation method, the titanium alkoxide gas phase hydrolysis method, the titanium alkoxide gas phase decomposition method and the like have small application range because the gas phase method has high requirements on equipment conditions, is difficult to operate and has high cost; the liquid phase method comprises a sulfuric acid method, a hydrochloric acid method, a sol-gel method, a chloride liquid phase hydrolysis method, a hydrothermal method, a micro-emulsion method and the like, and the liquid phase method has the advantages of lower equipment requirement, easiness in operation, wide raw material source and low cost, and is a common preparation method. The titanium dioxide produced in the industry today is predominantly gas-phase TiCl 4 The method, the liquid-phase sulfuric acid method and the titanium alkoxide liquid-phase hydrolysis method are mainly used in China. The prior sulfuric acid method for preparing titanium dioxide has the advantages of simple and mature process, easily obtained raw materials, lower cost, simple equipment and the likeBut is liable to introduce impurities to result in a decrease in product purity.
Chinese patent publication No. CN110357153A discloses a method for preparing high-purity titanium dioxide by hydrothermal method from industrial metatitanic acid, which comprises the following steps: adding water to industrial metatitanic acid for dispersing, filtering and washing until no ferrous ion exists in washing liquid; adding water again for dispersion to obtain slurry; carrying out hydrothermal crystallization on the slurry at the temperature of 110 ℃ and 180 ℃ for 24-48 h; after the reaction is finished, cooling to 60-80 ℃, filtering, and washing until the washing liquid has no ferrous ions, so as to obtain a metatitanic acid filter cake; calcining at 840-900 ℃ to obtain the high-purity titanium dioxide with the purity of more than 99.87 percent. The hydrothermal crystallization is carried out in a special closed reactor, which is the core step of the method and is used for purifying metatitanic acid and improving the crystallization degree of metatitanic acid; the method has high equipment requirement and harsh reaction conditions, and is difficult to produce on a large scale.
Chinese patent publication No. CN104477981A discloses a method for preparing high purity titanium dioxide, which comprises adding water into metatitanic acid, pulping, adding depolymerizing agent into the slurry, dispersing, and adding alkaline solvent to adjust pH to 7-10; squeezing, washing with water, and pulping with water; adding depolymerizing agent for dispersion, adding acid solvent to adjust pH to 1.0-2.0; and squeezing the obtained slurry, washing with water, calcining, cooling and crushing to obtain the high-purity titanium dioxide product. Wherein, the purpose of adding the depolymerizing agent is to fully disperse the obtained slurry and avoid agglomeration, and the method is complicated and has harsh reaction conditions.
Disclosure of Invention
Aiming at the problems that titanium dioxide prepared by a sulfuric acid method in the prior art still has a small amount of elements such as phosphorus, niobium, zirconium and the like, and the purity is to be improved, the invention provides a method for preparing high-purity nano titanium dioxide by a sulfuric acid method, the nano titanium dioxide is prepared by carrying out acidolysis, secondary hydrolysis, washing, calcination and other operations on metatitanic acid, the purity of the prepared nano titanium dioxide is high and reaches more than 99.9%, the particle size is easy to control, and the sphericity is better.
The technical scheme is as follows:
a method for preparing high-purity nano titanium dioxide by a sulfuric acid method comprises the following steps:
(1) carrying out acidolysis on metatitanic acid powder by using concentrated sulfuric acid to obtain acidolysis solution, and adding water to dilute the acidolysis solution to obtain titanyl sulfate solution; the concentration of the titanyl sulfate solution is 30-500g/L based on the mass of the titanium dioxide;
(2) slowly adding the titanyl sulfate solution into a dilute sulfuric acid solution of an organic dispersant for hydrolysis, wherein the hydrolysis temperature is 30-90 ℃, the addition time is 2-12 h, and then carrying out heat preservation and aging to obtain titanium dioxide slurry;
(3) filtering and washing titanium dioxide slurry, adjusting the pH value to 8-10, stirring and aging for 2-5 hours, adding ammonium sulfate, filtering and drying to obtain powder;
(4) and (4) calcining the powder prepared in the step (3) at 400-700 ℃ to prepare the high-purity nano titanium dioxide.
The method comprises the steps of carrying out acidolysis on metatitanic acid powder by concentrated sulfuric acid to obtain titanyl sulfate solution free of iron and magnesium impurities, and then carrying out hydrolysis on the titanyl sulfate solution (the hydrolysis process is reaction: TiOSO) 4 +2H 2 O=TiO 2 .nH 2 O+H 2 SO 4 ) And the conditions of the hydrolysis process are regulated and controlled, the growth of the product titanium dioxide is controlled, impurity elements are further removed, and the nano titanium dioxide with better dispersity and high purity is prepared.
Preferably, the metatitanic acid powder can be prepared by the following method: carrying out acidolysis on titanium ore by concentrated sulfuric acid, preparing titanium ore acidolysis solution by settling, filtering, crystallizing by ferrous sulfate, separating, and concentrating the titanium solution, hydrolyzing the titanium ore acidolysis solution to obtain metatitanic acid, washing the metatitanic acid with water, and bleaching to obtain pure metatitanic acid powder.
Preferably, in the step (1), the acidolysis temperature is 90-200 ℃; in the acidolysis process, concentrated sulfuric acid is heated to 90-200 ℃, and then metatitanic acid powder is slowly added while stirring, so that metatitanic acid is prevented from hardening. Dissolving metatitanic acid powder in concentrated sulfuric acid to obtain brown transparent viscous acidolysis solution.
Further preferably, the acidolysis temperature is 150 to 200 ℃; the concentration of the titanyl sulfate solution is 150g/L in terms of the mass of the titanium dioxide; the acidolysis speed can be accelerated by raising the temperature, and metatitanic acid can be dissolved by less concentrated sulfuric acid; however, if the temperature is too high, the metatitanic acid may be hardened, which may affect the dissolution effect.
The organic dispersant is polyol polyether, titanate coupling agent, polyacrylic acid ammonium salt, polycarboxylic acid ammonium salt or polyvinylpyrrolidone; the polyol polyether comprises polyoxyethylene lauryl ether, nonapolyethylene glycol monodecane ether, nonyl glycol monoether or alcohol polyoxyethylene ether. The organic dispersing agent is added to effectively reduce agglomeration in the hydrolysis process of metatitanic acid to form titanium dioxide prepolymer with good dispersity and sphericity, and the organic dispersing agent is beneficial to removal in subsequent washing and calcining steps, so that the purity of titanium dioxide is ensured.
Preferably, the organic dispersant is a titanate coupling agent, an ammonium polyacrylate salt or an ammonium polycarboxylate salt; the content of the organic dispersant is 0.1-3% by mass of titanium dioxide in the hydrolysis system.
Preferably, in the step (2), the concentration of sulfuric acid in the hydrolysis system is controlled to be 10% -15%, the hydrolysis speed of titanyl sulfate can be controlled by controlling the concentration of sulfuric acid in the hydrolysis system within the range, and meanwhile, the hydrolysis of a small amount of metal ions such as iron, manganese and the like in the solution is reduced, and the purity of titanium dioxide is improved; dividing the titanyl sulfate solution into a first titanyl sulfate solution and a second titanyl sulfate solution according to the volume ratio of 1: 5-50, and respectively adding the first titanyl sulfate solution and the second titanyl sulfate solution into the organic dispersant solution for two-stage hydrolysis; the hydrolysis temperature of the first stage is 30-60 ℃, and the adding time of the first titanyl sulfate solution is 0.5-2 h; the second stage hydrolysis is 70-90 ℃, and the adding time of the second titanyl sulfate solution is 1.5-10 h.
Preferably, in the step (3), ammonia water is used for adjusting the pH value to 8.5-9.5, and stirring and aging are carried out for 3-4 hours to promote crystal form conversion; the adding amount of ammonium sulfate is 0.5-2% by mass of titanium dioxide in the titanium dioxide slurry. The addition of ammonium sulfate can promote the dehydration of titanium dioxide prepolymer to titanium dioxide conversion in the calcining process to be carried out at a lower temperature, and reduce the agglomeration among titanium dioxide particles.
Preferably, in the step (4), the powder prepared in the step (3) is calcined at 400-500 ℃. The calcination temperature in the prior art is usually around 800 ℃, and the calcination temperature can be significantly reduced by controlling the hydrolysis process and adding ammonium sulfate in the step (3).
The invention also provides high-purity nano titanium dioxide prepared by the method for preparing the high-purity nano titanium dioxide by the sulfuric acid method; the high-purity nano titanium dioxide has good dispersibility, and the purity is more than or equal to 99.9 percent.
Compared with the prior art, the invention has the beneficial effects that:
(1) the method of the invention carries out acidolysis on metatitanic acid to obtain titanyl sulfate solution without iron and magnesium impurities; and then secondary hydrolysis and washing are carried out to effectively reduce elements such as phosphorus, niobium, zirconium and the like in the product, so that the prepared nano titanium dioxide has high purity.
(2) The invention utilizes the purer titanyl sulfate solution for hydrolysis, has no influence of iron and magnesium ions, lower hydrolysis temperature and low hydrolysis acidity condition; by controlling the hydrolysis temperature, the hydrolysis time, the organic dispersant and the like, the growth of titanium dioxide particles obtained by hydrolysis is further controlled, and the high-purity nano titanium dioxide with better dispersity is obtained.
(3) The high-purity nano titanium dioxide prepared by the method has the advantages of easy control of particle size and better sphericity.
Drawings
FIG. 1 shows high purity nano-titania obtained in example 1.
FIG. 2 shows titanium dioxide obtained in comparative example 1.
Detailed Description
The invention is further elucidated with reference to the figures and the examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention.
The metatitanic acids of examples 1 to 4 and comparative example 1 were prepared as follows: carrying out acidolysis on titanium ore by concentrated sulfuric acid, preparing titanium ore acidolysis solution by settling, filtering, crystallizing by ferrous sulfate, separating, and concentrating the titanium solution, hydrolyzing the titanium ore acidolysis solution to obtain metatitanic acid, washing the metatitanic acid with water, and bleaching to obtain pure metatitanic acid powder.
Example 1
(1) Preparing a titanyl sulfate solution: heating 500g of concentrated sulfuric acid to 100 ℃, slowly adding metatitanic acid powder while stirring, obtaining brown transparent viscous acidolysis solution after metatitanic acid is completely dissolved, cooling, and slowly adding deionized water to dilute to 1000mL to obtain titanyl sulfate solution, wherein the concentration of the titanyl sulfate solution is about 300g/L based on the mass of titanium dioxide.
(2) Hydrolysis of titanyl sulfate: taking 3g of polyacrylic acid ammonium salt dispersant (the content of the organic dispersant is 1 percent based on the mass of titanium dioxide in a hydrolysis system), dispersing in 100mL of dilute sulfuric acid with the mass fraction of 10 percent to prepare an organic dispersant solution, heating to 50 ℃, slowly adding 100mL of titanyl sulfate solution obtained in the step (1), simultaneously adding a proper amount of deionized water to keep the concentration of sulfuric acid in the solution at 10 percent, and adding for 1 hour; heating to 80 ℃, continuously adding the rest 900mL of titanyl sulfate solution obtained in the step (1) for 10h, and simultaneously adding a proper amount of deionized water to keep the concentration of sulfuric acid in the solution at 10%; then preserving heat and aging for 2h to obtain titanium dioxide slurry.
(3) And (3) titanium dioxide purification: filtering and washing the titanium dioxide slurry, removing sulfuric acid adsorbed on the surface, adding ammonia water to adjust the pH value to 9, stirring and aging for 3 hours to promote crystal form conversion, then adding 3g of ammonium sulfate (the adding amount of the ammonium sulfate is 1 percent based on the mass of titanium dioxide in the titanium dioxide slurry), filtering and drying to obtain powder.
(4) And (3) calcining: calcining the powder prepared in the step (3) at 500 ℃, cooling and crushing to obtain the high-purity nano titanium dioxide.
The SEM image of the nano titanium dioxide prepared by the embodiment is shown in FIG. 1, the particle size of the prepared titanium dioxide is 50-100 nm, the titanium dioxide is mostly spherical, and the dispersibility is good; the purity of the nano-titania obtained in this example was measured by X-ray fluorescence spectroscopy (XRF) and the results are shown in table 1:
TABLE 1 analysis of the composition of the nano-titanium dioxide obtained in example 1
Composition (I) | TiO 2 | P 2 O 5 | Nb 2 O 5 | ZrO 2 |
Content (%) | 99.96 | 0.014 | 0.0092 | 0.009 |
Comparative example 1
(1) And (3) calcining: calcining metatitanic acid powder at 700 ℃, cooling and crushing to obtain titanium dioxide powder.
The SEM image of the titanium dioxide prepared in this comparative example is shown in FIG. 2, and the purity of the titanium dioxide prepared in this comparative example was measured by X-ray fluorescence spectroscopy (XRF) and the results are shown in Table 2:
TABLE 2 compositional analysis of titanium dioxide obtained in comparative example 1
Composition (I) | TiO 2 | P 2 O 5 | Nb 2 O 5 | ZrO 2 |
Content (%) | 99.84 | 0.059 | 0.0213 | 0.082 |
Example 2
(1) Preparing a titanyl sulfate solution: heating 500g of concentrated sulfuric acid to 100 ℃, slowly adding metatitanic acid powder while stirring, obtaining brown transparent viscous acidolysis solution after metatitanic acid is completely dissolved, cooling, slowly adding deionized water to a constant volume of 1000mL to obtain titanyl sulfate solution, wherein the concentration of the titanyl sulfate solution is about 300g/L based on the mass of titanium dioxide.
(2) Titanyl sulfate hydrolysis: taking 3g of polycarboxylic acid ammonium salt dispersant (the content of the organic dispersant is 1 percent based on the mass of titanium dioxide in a hydrolysis system), dispersing the polycarboxylic acid ammonium salt dispersant in 100mL of dilute sulfuric acid with the mass fraction of 10 percent to prepare an organic dispersant solution, heating the solution to 60 ℃, slowly adding 100mL of the titanyl sulfate solution obtained in the step (1), simultaneously adding a proper amount of deionized water to keep the concentration of sulfuric acid in the solution to be 10 percent, and adding the solution for 1 hour; heating to 80 ℃, continuously adding the rest 900mL of titanyl sulfate solution obtained in the step (1) for 10h, and simultaneously adding a proper amount of deionized water to keep the concentration of sulfuric acid in the solution at 10%; then preserving heat and aging for 2h to obtain titanium dioxide slurry.
(3) And (3) titanium dioxide purification: filtering and washing the titanium dioxide slurry, removing sulfuric acid adsorbed on the surface, adding ammonia water to adjust the pH value to 9, stirring and aging for 3 hours to promote crystal form conversion, then adding 3g of ammonium sulfate (the mass of the titanium dioxide in the titanium dioxide slurry is calculated, and the adding amount of the ammonium sulfate is 1%), filtering and drying to obtain powder.
(4) And (3) calcining: calcining the powder prepared in the step (3) at 500 ℃, cooling and crushing to obtain the high-purity nano titanium dioxide.
Example 3
(1) Preparing titanyl sulfate solution: heating 200g of concentrated sulfuric acid to 200 ℃, slowly adding metatitanic acid powder while stirring, obtaining brown transparent viscous acidolysis solution after metatitanic acid is completely dissolved, cooling, slowly adding deionized water to a constant volume of 1000mL to obtain titanyl sulfate solution, wherein the concentration of the titanyl sulfate solution is about 200g/L based on the mass of titanium dioxide.
(2) Hydrolysis of titanyl sulfate: dispersing 2g of titanate coupling agent (the content of the organic dispersant is 1 percent based on the mass of titanium dioxide in a hydrolysis system) in 100mL of dilute sulfuric acid with the mass fraction of 15 percent to prepare an organic dispersant solution, heating to 90 ℃, slowly adding 20mL of titanyl sulfate solution obtained in the step (1), adding a proper amount of deionized water to keep the concentration of sulfuric acid in the solution at 15 percent, and adding for 2 hours; keeping the temperature at 90 ℃, continuously adding the rest 980mL of titanyl sulfate solution for 2h, and simultaneously adding a proper amount of deionized water to keep the concentration of sulfuric acid in the solution at 15%; then preserving heat and aging for 4 hours to obtain titanium dioxide slurry.
(3) And (3) purifying titanium dioxide: filtering and washing the titanium dioxide slurry, removing sulfuric acid adsorbed on the surface, adding ammonia water to adjust the pH value to 8, stirring and aging for 4 hours to promote crystal form conversion, then adding 1g of ammonium sulfate (the adding amount of the ammonium sulfate is 0.5 percent based on the mass of the titanium dioxide in the titanium dioxide slurry), filtering and drying to obtain powder.
(4) And (3) calcining: calcining the powder prepared in the step (3) at 600 ℃, cooling and crushing to obtain the high-purity nano titanium dioxide.
Example 4
(1) Preparing titanyl sulfate solution: heating 800g of concentrated sulfuric acid to 180 ℃, slowly adding metatitanic acid powder while stirring, obtaining brown transparent viscous acidolysis solution after metatitanic acid is completely dissolved, cooling, slowly adding deionized water to a constant volume of 1000mL to obtain titanyl sulfate solution, wherein the concentration of the titanyl sulfate solution is about 220g/L based on the mass of titanium dioxide.
(2) Hydrolysis of titanyl sulfate: taking 1g of lauryl alcohol polyoxyethylene ether (the mass of titanium dioxide in a hydrolysis system is calculated, and the content of the organic dispersant is 0.45 percent), dispersing the lauryl alcohol polyoxyethylene ether in 100mL of dilute sulfuric acid with the mass fraction of 10 percent to prepare an organic dispersant solution, heating the solution to 40 ℃, slowly adding 150mL of titanyl sulfate solution obtained in the step (1), adding a proper amount of deionized water to keep the concentration of sulfuric acid in the solution to be 10 percent, and adding the deionized water for 0.5 h; heating to 70 ℃, continuously adding the residual 850mL of titanyl sulfate solution obtained in the step (1) for 5h, and simultaneously adding a proper amount of deionized water to keep the concentration of sulfuric acid in the solution at 10%; then preserving heat and aging for 5h to obtain titanium dioxide slurry.
(3) And (3) titanium dioxide purification: filtering and washing the titanium dioxide slurry, removing sulfuric acid adsorbed on the surface, adding ammonia water to adjust the pH value to 10, stirring and aging for 3 hours to promote crystal form conversion, then adding 4g of ammonium sulfate (the adding amount of the ammonium sulfate is 1.8 percent based on the mass of titanium dioxide in the titanium dioxide slurry), filtering and drying to obtain powder.
(4) And (3) calcining: calcining the powder prepared in the step (3) at 700 ℃, cooling and crushing to obtain the high-purity nano titanium dioxide.
The embodiments described above are intended to illustrate the technical solutions of the present invention in detail, and it should be understood that the above-mentioned embodiments are only specific embodiments of the present invention, and are not intended to limit the present invention, and any modification, supplement or similar substitution made within the scope of the principles of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A method for preparing high-purity nano titanium dioxide by a sulfuric acid method is characterized by comprising the following steps:
(1) carrying out acidolysis on metatitanic acid powder by using concentrated sulfuric acid to obtain acidolysis solution, and diluting the acidolysis solution to obtain titanyl sulfate solution; the concentration of the titanyl sulfate solution is 30-500g/L based on the mass of the titanium dioxide;
(2) slowly adding the titanyl sulfate solution into the organic dispersant solution for hydrolysis at the hydrolysis temperature of 30-90 ℃ for 2-12 h, and then preserving heat and aging to obtain titanium dioxide slurry;
(3) filtering and washing titanium dioxide slurry, adjusting the pH value to 8-10, stirring and aging for 2-5 hours, adding ammonium sulfate, filtering and drying to obtain powder;
(4) and (4) calcining the powder prepared in the step (3) at 400-700 ℃ to prepare the high-purity nano titanium dioxide.
2. The method for preparing high-purity nano titanium dioxide according to the sulfuric acid process of claim 1, wherein in the step (1), the acidolysis temperature is 90-200 ℃.
3. The method for preparing high-purity nano titanium dioxide according to the claim 1, wherein the organic dispersant is polyol polyether, titanate coupling agent, polyacrylic acid ammonium salt, polycarboxylic acid ammonium salt or polyvinylpyrrolidone; the polyol polyether comprises polyoxyethylene lauryl ether, nonapolyethylene glycol monodecane ether, nonyl glycol monoether or alcohol polyoxyethylene ether.
4. The method for preparing high-purity nano titanium dioxide according to the claim 1, wherein the organic dispersant is titanate coupling agent, polyacrylic acid ammonium salt or polycarboxylic acid ammonium salt; the content of the organic dispersant is 0.1-3 percent by mass of the titanium dioxide in the hydrolysis system.
5. The method for preparing high-purity nano titanium dioxide by the sulfuric acid process according to claim 1, wherein in the step (2), the concentration of sulfuric acid in a hydrolysis system is controlled to be 10% -15%; dividing the titanyl sulfate solution into a first titanyl sulfate solution and a second titanyl sulfate solution according to the volume ratio of 1: 5-50, and respectively adding the first titanyl sulfate solution and the second titanyl sulfate solution into the organic dispersant solution for two-stage hydrolysis; the hydrolysis temperature of the first stage is 30-60 ℃, and the adding time of the first titanyl sulfate solution is 0.5-2 h; the second stage hydrolysis is 70-90 ℃, and the adding time of the second titanyl sulfate solution is 1.5-10 h.
6. The method for preparing high-purity nano titanium dioxide according to claim 1, wherein in the step (3), ammonia water is used for adjusting the pH value to 8.5-9.5, and stirring and aging are carried out for 3-4 hours.
7. The method for preparing high-purity nano titanium dioxide by using the sulfuric acid method according to claim 1, wherein in the step (3), the addition amount of ammonium sulfate is 0.5-2% by mass of titanium dioxide in the titanium dioxide slurry.
8. The method for preparing high-purity nano titanium dioxide by the sulfuric acid process according to claim 1, wherein in the step (4), the powder prepared in the step (3) is calcined at 400-500 ℃.
9. The high-purity nano titanium dioxide prepared by the method for preparing the high-purity nano titanium dioxide according to any one of claims 1 to 8.
10. The sulfuric acid process for preparing high-purity nano titanium dioxide according to claim 9, wherein the purity is more than or equal to 99.9%.
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