Method of producing nanopowder zirconium, yttrium and titanium composite oxide

FIELD: chemistry.

SUBSTANCE: invention can be used in production of dense wear-resistant ceramic and solid electrolytes. The method of producing powder of a zirconium, yttrium and titanium composite oxide involves preparing a starting solution of nitrates, adding an organic acid and a titanium-containing compound into said solution, followed by heat treatment. The organic acid used is glycine in amount of 1.6-2.5 mol per 1 g-atom of the sum of metal cations (Zr+4+Ti+4+Y+3). The titanium-containing compound used is a hydrolysable titanium compound with the ratio Zr+4:Ti+4=(0.99-0.85):(0.15-0.01). The starting solution is further mixed with 30% hydrogen peroxide with the ratio H2O2:Ti+4=(4.7-12):1. The hydrolysable titanium compound used can be titanium tetrabutylate or titanium sulphate or titanium tetrachloride.

EFFECT: invention prevents waste discharge, reduces power consumption and simplifies production of nanopowder of a zirconium, titanium and yttrium composite oxide.

3 cl, 3 ex

 

The invention relates to the chemical industry, in particular to methods of producing fine powders stabilized zirconium oxide, partially replaced by titanium oxide, which can be used to produce a dense wear-resistant ceramics, solid electrolytes and elements of sofcs.

The known method of producing nanoscale double oxide of titanium and zirconium from solutions of tetrabutyrate titanium and isopropylate zirconium mixed with carboxylic acid. The reaction mixture was incubated for 8-24 h, washed with ethanol and dried (patent CH 101164898, IPC C01G 23/053, 2007).

The disadvantage of this method is the length of the process of esterification and the need to wash the product with ethanol.

A method of obtaining nanoparticles of oxides, in particular complex oxide of titanium and zirconium, in which the original use two solution: aqueous solution containing at least two metal salts and operauser agent and a second solution of pectin and mono - or disaccharide. Both solution are mixed at 100-110°C and maintained at this temperature to complete the process of melirovanie. Heat treatment of the mixture of the solutions are in the range of 500-1200°C (patent USA 7968609, IPC B01D 21/01, 2011).

The disadvantage of this method is the danger of hydrolysis of inorganic salts Titus is on in aqueous solutions of other salts and aggregation of the nanoparticles of the product under vysokotemperaturnom annealing (1000-1200°C).

A method of obtaining compounds based on oxides of titanium, lead, zirconium, namely, that in an alcoholic solution of the initial mixture of salts of the individual components introduce a solution of oxalic acid and titanium dioxide in the form of nanopowder with a mixture of the oxalates of the individual components, then the mixture of the oxalates are annealed in two stages: 320-370°C and 780°C with heating rate of 5 to 12 deg/min with time at a given temperature at each stage and cooling the reaction mass after each stage (patent RU 2379259, IPC C04B 35/491, 2010).

The disadvantage of this method is the need for a separately obtained nanopowder titanium dioxide dimension of less than 20 nm and a large amount of carbon monoxide generated during calcination. High corrosion activity of oxalic acid requires the use of special reactors for thermal treatment.

Closest to the proposed method of obtaining is the way to obtain a complex oxide of zirconium, yttrium, titanium using ORGANOMETALLIC precursor containing zirconium, titanium and yttrium, which is mixed with an aqueous solution of sodium hydroxide or potassium containing alcohol, and thermoablative at a temperature not higher than 350°C (application US 20100135937, IPC A61K 8/19, 2010) (prototype).

The disadvantage of izvestno the method is its complexity, as well as the use of a large number of organic compounds.

Thus, the authors goal was to develop a simple and reliable method of obtaining nanosized powder-based complex oxide of zirconium, yttrium and titanium.

The problem is solved in the proposed method of obtaining nanopowder complex of zirconium oxide, yttrium and titanium, comprising preparing a starting solution of salts of nitrates, the introduction of organic acid and titanium containing compounds, and the subsequent heat treatment, in which the organic acid is used glycine based 1,6÷2,5 mol per 1 g-atom of the amount of metal cations (Zr+4+Ti+4+Y+3), and as such compounds are used gidrolizuyutza compound of titanium with a ratio Zr+4:Ti+4=0,99÷0,85:0,15÷0,01, the original solution was further added 30%hydrogen peroxide at a ratio of N2About2:Ti+4=4,7÷12:1.

However as gidrolizuyushchie compounds of titanium use tetrabutyl titanium or titanium sulfate or titanium tetrachloride.

In this case, the heat treatment is carried out in two stages at a temperature of 160-250°C on the 1st stage and at a temperature of 550-600°C on the 2nd stage.

At the present time of patent and technical literature is not a method of obtaining nanopowder SL is the author of zirconium oxide, titanium and yttrium, which in the original salt solution and glycine optionally add the hydrogen peroxide, enter the amount of which depends on the concentration of cations of titanium.

Research conducted by the authors, allowed to determine the conditions for obtaining nano and submicron powders on the basis of oxides of zirconium, titanium and yttrium. Failed to install, glycine (Gly) form a solid chelate complexes with cations ZrO2+, Y3+but also with the cation TiO2+that in the process of evaporation of the initial reaction solution prevents fractional allocation from the solution of the hydroxides and oxysalts, but leads to the formation of the ORGANOMETALLIC compound in the form of a xerogel with a low temperature exothermic decomposition (160-250°C). As a result of ignition of the dried reaction mixture results in the release of water vapor, carbon dioxide and elemental nitrogen, contributing to the formation of nanopowder product. The total amount of organic reducing agent provides complete conversion of nitrogen oxides to molecular nitrogen, but at the same time, stores the media for self replicating mode synthesis.

Known General principle of obtaining powders of metal oxides by evaporation and incineration aqueous solution of nitrate salts of the metals in the presence of amino acids, particularly glycine. One is to, aqueous solutions of titanyl nitrate is unstable and quickly decay into chemically inactive, hydrate, titanium oxide, not giving a solution with amino acids, which prevents the mixing of the components of the reaction medium at the molecular level.

Introduction in acidic solution zirconyl nitrate of tetrabutyrate titanium (titanium tetrachloride, titanium sulfate or other gidrolizuyushchie of titanium compounds) is accompanied by formation of a precipitate of titanium hydroxide, which does not react with amino acids, in particular glycine and insoluble. In the process of further drying the hydroxide of titanium becomes ballast compound in the reaction mixture, not entering fully into a chemical reaction with the formed zirconium oxide. A preliminary introduction to the solution of zirconyl nitrate hydrogen peroxide allows for the mixing translate the resulting titanium hydroxide in peroxinitrite of Titania-resistant storage in aqueous solution and its moderate heat, interacting with amino acids. After mixing with other metals nitrates and glycine homogeneous solution upon evaporation of the highlights solid xerogel based on a homogeneous mixture of the original glycine-nitrate complexes, which upon reaching a temperature 160-250°C enters the mode volume of burning or samovosproizvodyaschiesya emitting large amounts of heat and gaseous products of water vapor, nitrogen and carbon dioxide.

Experimental studies conducted by the authors, allowed to determine the optimal quantitative proportions of the starting components, completely eliminating the emission of nitrogen oxides, for example, by conducting the process in accordance with the following reactions: 0.9ZrO(NO3)2+0.10[TiO(H2O2)](NO3)2+1,5H2N(CH2)COOH+(1.65-x)O2=Zrfor 0.9Ti0.1O2+1.75N2+(3-x)CO2+3.85H2O+xC

0.855ZrO(NO3)2+0.05[TiO(H2O2)](NO3)2+0.19Y(NO3)3+2.5H2N(CH2)COOH+(2.625-x)O2=(http://Zro.855Tio.05O2)·(Y2O3)0.095+2.48N2+(5-x)CO2+6.3H2O+xC.

The content of hydrogen peroxide is taken on the basis of the formed water-soluble peroxide complexes of titanium. Reducing the number entered in the hydrogen peroxide solution is less than H2O2:Ti+4<4,7 not possible to achieve complete dissolution of the precipitate of titanium hydroxide or makes it unstable when further operations and storage. The increase in the number entered in the hydrogen peroxide solution in a ratio in excess of H2O2: Ti+4>12, is impractical because it leads to inappropriate waste of reagent.

The proposed method can be implemented as follows. Prepare a water solution containing zircon is l nitrate and yttrium nitrate in a molar ratio Zr +4:Y+3from (0,78-x):0.22 to (0,94 - x):0,06, where x=(0.01 to 0.15), add with stirring glycine from the calculation of 1.6 to 2.5 mol per 1 g-atom of the amount of metal cations and a solution of 30% hydrogen peroxide. Weighed in a separate vessel a portion of tetrabutyl titanium based Zr+4:Ti+4=(0,99-0.85):(0.01 to 0.15) and poured thereto under stirring with a solution of Zirconia and yttrium nitrate. Stirring is stopped after complete dissolution of the precipitated sludge. The amount of added hydrogen peroxide rely on the content of titanium in the sample of tetrabutyl titanium, keeping the ratio of N2About2:Ti+4=4,7÷12:1. The resulting reaction solution was heated in an open reactor from acid - and heat-resistant material when the temperature of the heater 160-250°C. In the process of heating the reaction solution forms a gelatinous mass that is transformed into a xerogel, which develops the SHS reaction with volatile components (carbon dioxide, and nitrogen) and water vapor and the formation of a powder of stabilized Zirconia and titanium. After completion of the combustion process, according to the chemical analysis of the obtained semi-finished product contains up to 8-10% carbon. After completion of the combustion process, according to the chemical analysis of the obtained semi-finished product contains up to 8% of carbon. It loads in a corundum crucible and annealed several the aces at a temperature of 550-600°C. After annealing the product does not contain traces of carbon and volatiles, is a weakly agglomerated nanopowder white with a high specific surface area.

Example 1. In the solution zirconyl nitrate containing 130 g/l Zr contribute to the solution of yttrium nitrate, containing 55 g/l of yttrium to obtain a solution with a ratio Zr+4:Y+3=0.87:0.20. Then the solution is added aminouksusnoy acid (glycine) at the rate of 1.6 mol per 1 g-atom of metal cations (Zr4++Ti4++Y3+and dissolve it by stirring.

Select 20% of the volume of the obtained solution Zirconia and yttrium nitrate in a separate container, add in a solution of 30%hydrogen peroxide based 4.7 g of the peroxide solution on g Ti and contribute in the capacity of a portion of tetrabutyrate (34,6% Ti) titanium, taken Zr+4:Ti+4=0.87:0.03 to the total content of zirconium with constant stirring. Stirring is continued until complete dissolution of the drop-down sediment. Then mix the remains of the original solution zirconyl nitrate and yttrium nitrate with such a solution.

The resulting reaction solution was heated portions of 0.5-0.6 l in an open reactor from acid - and heat-resistant material when the temperature of the heater 160°C. In the process of heating the reaction solution forms a gel-like mass is at and burns with carbon dioxide, nitrogen and water vapor, and the reactor is formed loose weight of a powder of yttrium-stabilized complex oxide of titanium and zirconium. The reactor is removed from the heater and cooled to room temperature, unload the received intermediate the holding tank and pour the next portion of the solution. After burning the entire solution obtained intermediate is stirred or subjected to grinding, after which it is loaded in corundum crucibles and annealed for 6 hours at 550°C. After annealing the product does not contain traces of carbon and volatiles, is a weakly agglomerated nanopowder white, with a specific surface area of 14 m2/, XRD shows that he is a nonequilibrium zirconium oxide-yttrium-titanium that does not contain a separate phases of oxides of zirconium, yttrium or titanium. After annealing the samples of powder at 1500°C sample has a cubic structure.

Example 2. In the solution zirconyl nitrate, containing in terms of 130 g/l of zirconium contribute to the solution of yttrium nitrate, containing 30 g/l of yttrium to obtain a solution with a ratio Zr+4:Y+3=0.79:0,06. Then the solution is added aminouksusnoy acid (glycine) at the rate of 2.5 mol per 1 g-atom of metal cations (Zr4++Ti4++Y3+and dissolve it by stirring.

Select 20% of the volume of the resulting solution C is ranila and yttrium nitrate in a separate container, add to it a solution of 30%hydrogen peroxide based 12.0 g of the peroxide solution on g Ti and contribute in the capacity of a portion of tetrabutyrate (34,6% Ti) titanium, taken Zr+4:Ti+4=0.79:0.15 to the total content of zirconium with constant stirring. Stirring is continued until complete dissolution of the drop-down sediment. Then mixed source solution zirconyl nitrate and yttrium nitrate with such a solution.

The resulting reaction solution was heated portions of 0.5-0.6 l is heated in an open reactor from acid - and heat-resistant material when the temperature of the heater 250°C. In the process of heating the reaction solution forms a gel-like mass and burns with carbon dioxide, nitrogen and water vapor, and the reactor is formed loose weight of a powder of yttrium-stabilized complex oxide of titanium and zirconium. The reactor is removed from the heater and cooled to room temperature, unload the received intermediate the holding tank and pour the next portion of the solution. After burning the entire solution obtained intermediate is stirred or subjected to grinding, after which it is loaded in corundum crucibles and annealed 5 hours at a temperature of 600°C. After annealing the product does not contain traces of carbon and volatiles, is a weakly agglomerated nano is whether submicron powder of white color, with a specific surface area of 15 m2/, RF And shows that he is a nonequilibrium zirconium oxide-yttrium-titanium that does not contain a separate phases of oxides of zirconium, yttrium or titanium. After annealing the samples of powder at 1500°C sample has a tetragonal structure.

Example 3. In the solution zirconyl nitrate, containing in terms of 130 g/l of zirconium contribute to the solution of yttrium nitrate, containing 30 g/l of yttrium to obtain a solution with a ratio Zr+4:Y+3=0.70:0,22. Then the solution is added aminouksusnoy acid (glycine) at the rate of 2.5 mol per 1 g-atom of metal cations (Zr4++Ti4++Y3+and dissolve it by stirring.

Select 20% of the volume of the obtained solution Zirconia and yttrium nitrate in a separate container, add in a solution of 30%hydrogen peroxide based 8.0 g of peroxide solution in 1 g Ti and contribute in the capacity of a portion of tetrabutyrate (34,6% Ti) titanium, taken Zr+4:Ti+4=0.70:0.08 to the total content of zirconium with constant stirring. Stirring is continued until complete dissolution of the drop-down sediment. Then mixed source solution zirconyl nitrate and yttrium nitrate with such a solution.

The resulting reaction solution was heated portions of 0.5-0.6 l is heated in an open reactor of acid and thermally with onogo material when the temperature of the heater 250°C. In the process of heating the reaction solution forms a gel-like mass and burns with carbon dioxide, nitrogen and water vapor, and the reactor is formed of loose mass of powder of stabilized zirconium oxide with the addition of titanium. The reactor is removed from the heater and cooled to room temperature, unload the received intermediate the holding tank and pour the next portion of the solution. After burning the entire solution obtained intermediate is stirred or subjected to grinding, after which it is loaded in corundum crucibles and annealed 5 hours at a temperature of 600°C. After annealing the product does not contain traces of carbon and volatiles, is a weakly agglomerated nano or submicron white powder with a specific surface area of 17 m2/, XRD shows that he is a nonequilibrium zirconium oxide-yttrium-titanium that does not contain a separate phases of oxides of zirconium, yttrium or titanium. After annealing the samples of powder at 1500°C sample has a cubic structure.

Thus, the authors propose a method of obtaining nanopowder compounds complex oxides of zirconium, titanium and yttrium, which is a highly eco-friendly as it eliminates the need to discharge wastewater in process cycle, reduces energy consumption and is easy tehnologicheskogo the solution.

1. The method of obtaining nanopowder complex of zirconium oxide, yttrium and titanium, comprising preparing a starting solution of salts of nitrates, the introduction of organic acid and titanium containing compounds and subsequent heat treatment, characterized in that the organic acid is used glycine based 1,6÷2,5 mol per 1 g-atom of the amount of metal cations (Zr+4+Ti+4+Y+3), and as such compounds are used gidrolizuyutza compound of titanium with a ratio Zr+4:Ti+4=(0,99÷0,85):(0,15÷0,01), the original solution was further added 30%hydrogen peroxide at a ratio of H2O2:Ti+4=(4,7÷12):1.

2. The method according to claim 1, characterized in that as gidrolizuyushchie compounds of titanium use tetrabutyl titanium, or titanium sulfate or titanium tetrachloride.

3. The method according to claim 1, characterized in that the heat treatment is carried out in two stages, at a temperature of 160-250°C on the 1st stage and at a temperature of 550-600°C on the 2nd stage.



 

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1 tbl, 2 ex

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SUBSTANCE: invention can be used for photocatalytic treatment of water and air from organic compounds and pathogenic flora, with photocatalytic decomposition of water. In order to obtain a photocatalytic nanocomposite containing titanium dioxide, a transition metal salt is added in amount of 1.5-60 wt % in terms of metal to a titanium (IV) salt solution with concentration of 1.0-2.5 mol/l TiO2 while stirring and the salts undergo hydrolysis in ammonium hydroxide solution at 15-25°C for 0.1-0.25 hours with formation of a precipitate. The obtained precipitate is settled for 1.5-2.0 hours, separated, washed and thermally processed at 80-800°C for 0.5-1.0 hours. The titanium (IV) salt used is a chloride or sulphate, the iron (III) salt used is a chloride, sulphate or nitrate, the niobium (V) salt used is a fluoride and the tungsten (VI) salt used is sodium tungstate.

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9 cl, 1 tbl

FIELD: chemistry.

SUBSTANCE: method of preparing aqueous dispersions of TiO2 nanoparticles in form of anatase involves reaction of titanium alkoxide with water in the presence of a mineral acid and a nonionic surfactant while heating. The titanium alkoxide is selected from a group comprising titanium methoxide, ethoxide, n-propoxide, isopropoxide, n-butoxide and isobutoxide. The mineral acid is a halogen acid. The surfactants have a polar functional group of the ether or ester type. The titanium alkoxide/halogen acid molar ratio ranges from 0.005 to 15. In an alternative method, the solution which contains titanium alkoxide, mineral acid and surfactant is mixed with a transition metal salt, for example Ag or Cu or Ce, and a dispersion of TiO2 nanoparticles is obtained, where Ti is deposited on the said metal. The obtained dispersions of TiO2 nanoparticles are used to produce photocatalytic coatings on a surface which requires such processing, as well as for photocatalytic cleaning of gases and liquids.

EFFECT: method enables to obtain a dispersion of TiO2 nanoparticles which do not exhibit adhesion, coagulation and deposition of a solid material even after prolonged storage of the dispersed product, and are uniform, have photocatalytic activity and are transparent.

18 cl, 1 dwg, 7 ex

FIELD: process engineering.

SUBSTANCE: invention relates to production of photocatalysts. Proposed method consists in preparing water solution of titanyl sulphate with concentration of 0.1-1.0 mol/l, adding acid thereto obtain concentration of 0.15-1 mol/l, hydrolysis of obtained solution in hydrothermal conditions at 100-250°C for 0.5-24 h, and drying of produced suspension of porous titanium dioxide.

EFFECT: production of porous photocatalyst with high specific surface and photocatalytic ctivity.

6 cl, 4 tbl, 2 dwg, 4 ex

FIELD: chemistry.

SUBSTANCE: invention can be used in chemical industry to extract rare-earth elements from phosphogypsum. The method involves carbonising phosphogypsum to obtain phosphochalk, dissolving said phosphochalk in nitric acid to obtain a product suspension and then separating the insoluble residue - a black concentrate of rare-earth elements - by filtering. The product suspension is divided into two parts, one of which is fed for filtration to separate the insoluble residue - black concentrate, and the second is fed for premixing with nitric acid. The mixing process is carried out for 3-5 minutes with the ratio CaO/HNO3 equal to 0.75-2.25. When dissolving, pH is kept at 2.2-4.

EFFECT: invention enables to extract rare-earth elements from phosphogypsum in form of a back concentrate with high content of rare-earth elements and stabilise the process in industrial conditions.

4 tbl, 5 ex

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