The method of producing titanium dioxide

 

(57) Abstract:

The invention relates to a method for producing titanium dioxide by hydrolysis of solutions of alkoxides of titanium. The result of the invention is to create an effective method to obtain powders of Tio2with predetermined particle sizes, which are determined by the conditions of the experiment. The method is carried out by hydrolysis of titanium alcoholate with water or a water-alcohol mixture in two successive stages at a molar ratio of water to the alcoholate 1-1,5 at the first stage and a 10-15 second stage and extracts the mixture obtained in the first stage of hydrolysis, before the second stage of hydrolysis. As alcoholate use Ti(Ovi)4in the form of its solution in butyl alcohol with a concentration of 0.2-0.8 M and the exposure is carried out at 20-65oC for 1-4 hours 1 tab., 4 Il.

The invention relates to a method for producing powder of titanium dioxide used in various engineering industries. Titanium dioxide is used as a source of raw materials during sintering of many types of ceramic materials of capacitors, position, piezoelectric elements, in particular barium titanate, zirconium titanate, lead zirconate titanate, and others. Sintering behavior of the powder is about the size of the particles. The powder of titanium dioxide of high purity and morphological homogeneity is also used to create inorganic membranes for ultrafiltration, in the production of sensor elements, and may also find application in the cosmetic industry and in the manufacture of dyes.

In recent decades, the widely used method of obtaining TiO2by hydrolysis of solutions of titanium alcoholate. This method allows to synthesize powders of titanium dioxide of high purity (due to the possibility of deep cleaning materials - volatile metal alcoholate).

However, the regulation of the particle size is a very difficult task. During hydrolysis, as a rule, produced the smallest particles (with an average size of < 0.05 microns), which has a very high tendency to agglomerate, stick together in large dense aggregates, considerably reducing the sintering of powders, as well as complicating their use in all the above directions.

In the application Japan N 63-139005 (class C 01 B 13/32, C 01 F 11/04, op. 10.06.88) to obtain monodisperse powder of titanium dioxide solution isopropylate titanium alcohol was sprayed through a nozzle in the form of droplets in an alcohol solution of water. Raznie and is only suitable for use dilute solutions.

In the work Look J. L, Zukoski C F (J. Am. Ceram. Soc. 1992, V 75, N 6, p. 1587) proposed to carry out the hydrolysis of ateleta titanium in the presence of an electrolyte - HCl or NaCl, which leads to the creation of an electrostatic charge on the surface formed during hydrolysis of the particles and prevents their agglomeration. However, the introduction of inorganic impurities, in particular cations of alkali metals, it is unacceptable for most applications TiO2in the production of materials for electronics. To remove traces of chlorine usually cannot even during high-temperature processing.

It is proposed to use organic additives, in particular, in U.S. patent N 4732750 (class C 01 G 25/02, op. 22.03.88) to regulate the size of the resulting particles in a solution of the alcoholate to impose certain number of triethylamine and gidroksipropilzelluloza. Supplementation pollutes titanium dioxide: for removal of the target product has to be subjected to high temperature processing, which affects the morphology of the powder, particularly undesirable bad remove the impurity of nitrogen.

In the application of Stampante Y. M. and others (application USSR N 674990, class C 01 G 23/053, op. 25.07.79) to obtain a titanium dioxide carry out the hydrolysis of butyl titanium large excess of water in the form of logindisable particles, and agglomerates with a size of 400-1000 microns, is not suitable as charge for the sintering of ceramics. In addition, Econoline-buchanania mixture, which is a by-product of hydrolysis, difficult to split. Thus, the proposed technique cannot be considered as a technological method of obtaining TiO2.

Closest to the proposed invention is a method for TiO2of the titanium alkoxide (abstract to the application Japan N 2-18323, class C 01 G 23/053, op. 22.01.90), including its hydrolysis in two stages. First, the titanium alkoxide is treated with a water-alcohol solution containing 1-2 mol H2O, the reaction mixture is heated and kept in for some time, and then it is distilled alcohol. To the obtained in the first stage titanocene again add water-alcohol solution so that the total amount of water introduced into the system at both stages was 2-40 mol. The formed particles of titanium dioxide have a size of 0.3-1 μm.

The disadvantage of the proposed method is the presence of a stage of removal of the solvent, which not only is a very tedious process, but also significantly affects the morphological characteristics of the final product. Isplay powder TiO2as evidenced by the wide distribution of the resulting particles, and leads to the hydrolysis products with a very high specific surface area (250-550 m2/g), fusible annealing in highly agglomerated powders TiO2. The same terms and conditions mentioned in the patent for hydrolysis of various alcoholate of titanium, as well as the lack of the necessary combination of options for carrying out hydrolysis does not make it possible to adjust the particle size and to obtain monodisperse powders with a narrow distribution of particle sizes.

The technical task of the present invention is to provide an efficient method of obtaining powders of TiO2with predetermined particle sizes, which are determined by the conditions of the experiment.

This is achieved by using as the source of the alcoholate - Ti(OBu)4available, easily dosed, and less prone to hydrolysis, compared to other Ti(OR)4in the form of 0.2 to 0.8 M solution in BuOH, maintaining the solution after the first hydrolysis step and before performing the second stage of hydrolysis within 1-4 hours at a temperature of 20-65oC.

A characteristic feature of Ti(OBu)4is rest if ethylate and isopropylate titanium oxoalcohols - crystalline substances, see Day V. W., Eberspacher T. D., Chen Y., Hao J., W. G. Klemperer, Inorganica Chimica Acta 1995, V 229, p. 391). The rate of hydrolysis oxobutyrate significantly below the rate of hydrolysis of the original alcoholate, which allows homogeneous nucleation in solutions by separation of hydrolysis in two stages. Changes in the concentration of a solution of Ti(OBu)4time and temperature of exposure between the first and second stages of hydrolysis allows you to adjust the size of the resulting particles in the range from 0.1 to 1.4 μm and get the hydrolysis product with a predetermined morphology preserved in the further heat treatment.

The essence of the proposed method lies in the fact that hydrolysis in two stages water or water-butanolide solution are solutions of Ti(OBu)4with a concentration of from 0.2 to 0.8 M, and obtained in the first stage the solution before carrying out the second stage of hydrolysis was incubated for 1-4 hours at a temperature of 20-65oC. the Formed precipitate was separated from the mother liquor by centrifugation and dried at 120oC in air. The decrease in the concentration of a solution of Ti(OBu)4and the increase in temperature and exposure time partially hydrolyzed solution leads to an increase in the size of h is th method differs from the known as source of the alcoholate used butyl titanium in the form of its solution in butyl alcohol with a concentration of 0.2 to 0.8 M, obtained in the first stage the solution before carrying out the second stage of hydrolysis was incubated for 1 to 4 hours at a temperature of 20-65oC. Thus, the claimed method meets the criterion of "novelty."

In the literature there are known methods of obtaining titanium dioxide upon hydrolysis of the alcoholate solutions, but none of the known methods do not describe the possibility of regulating the dispersion of the powder TiO2when the separation of hydrolysis in two stages and conditions of implementation of this process. This allows to make a conclusion on the conformity of the proposed method the criterion of "inventive step".

Example 1.

In a reactor with a stirrer in a volume of 1 l, made of titanium, download 150,0 g (0,44 M) tetramethoxysilane and 400 ml of butyl alcohol. Separately prepare a solution of water: mix until complete homogeneity 11,91 g (0.66 M) of distilled water and 135 ml of butanol. In the resulting 0.8 M solution of tetraethoxysilane with vigorous stirring pour in 4.5 M solution of water (the ratio h=[H2O2]:[Ti(OBu)4] or=1.5). Stopping stirring, the formed with the transparent solution), then cooled to room temperature and add another 68 g (3.77 Feet) of distilled water, bringing the ratio of h to 10. The resulting suspension of amorphous titanium dioxide is separated from the mother liquor by centrifugation and dried in air at 120oC. the result of 50.5 g of the powder with an average particle size of 0.8 μm (Fig. 1). The average size and distribution parameters were calculated by electronic microphotographs manually, based in each case from ~1000 particles.

Example 2.

In a reactor with a stirrer in a volume of 1 l, made of titanium, download 150,0 g (0,44 M) tetramethoxysilane and 400 ml of butyl alcohol. Separately prepare a solution of water: mix until complete homogeneity 7,94 g (0,44 M) of distilled water and 90 ml of butanol. In the resulting 0.8 M solution of tetraethoxysilane with vigorous stirring pour in 4.5 M solution of water (the ratio h= [H2O]:[Ti(OBu)4]=1). Stopping stirring, the resulting solution is heated to 65oC and kept at this temperature for 1 h, then cooled to room temperature and add another 72 g (4.0 M) of distilled water, bringing the ratio of h to 10. The resulting suspension of amorphous titanium dioxide is separated from the mother liquor centrifuge is µm (Fig. 2).

Example 3.

All operations is carried out, as in example 2, however, formed after adding the first portion of water, the solution was incubated for 1 h at room temperature. The result is a powder with an average particle size of 0.2-0.3 μm (Fig. 3).

Example 4.

In a glass reactor with stirrer volume of 250 ml load of 10.0 g (0,029 M) tetramethoxysilane and 63 ml of butyl alcohol. Separately prepare a solution of water: mix until complete homogeneity of 0.53 g (0,029 M) of distilled water and 72,5 ml of butanol. Received 0.4 M solution of tetraethoxysilane with vigorous stirring pour in an equal volume of 0.4 M solution of water (the ratio h=[H2O]:[Ti(OBu)4]=1). Stirring is continued for 0.5-1 min, and then stop and maintain the resulting solution for 4 h at room temperature. At the same time prepare a solution of water with mixing until complete homogeneity of 7.4 g of distilled water and 140 ml of butanol. At the end of the exposure time to the resulting partially hydrolized solution with a concentration of 0.2 M to add when mixing equal volume of 2.8 M solution of water, bringing the ratio of h to 15. Particles of amorphous titanium dioxide begin to precipitate from solution through ituverava and dried in air at 120oC. the result of 3.3 g of the powder with an average particle size of 1.4 μm (Fig. 4).

The results are presented in the table.

The method of obtaining titanium dioxide, comprising the hydrolysis of the titanium alcoholate with water or a water-alcohol mixture in two successive stages at a molar ratio of water to the alcoholate 1-1,5 at the first stage and a 10-15 second stage and the extract mixture obtained in the first stage of hydrolysis, before the second stage of hydrolysis, characterized in that as alcoholate using Ti(OBu)4in the form of its solution in butyl alcohol with a concentration of 0.2-0.8 M and the exposure is carried out at 20-65oC for 1-4 hours

 

Same patents:

The invention relates to a method for producing pigmentary titanium dioxide from titanium containing waste, which can be used in the manufacture of paints and as a component for creating white
The invention relates to the production of compounds of titanium, such as titanium dioxide

FIELD: mining industry.

SUBSTANCE: perovskite concentrate, which can be used for manufacture of pigment titanium dioxide for paints, paper, enamels, and plastics, is processed as follows. 1 kg of concentrate is treated under atmosphere conditions with concentrated HCl at 90-100оС for 10 to 20 h to solubilize 75-85% of titanium, radioactive, and other acid-soluble components. Concentration of HCl is then lowered by diluting it with 1-5% HCl solution until TiO2 concentration 50-100 g/L. Thermohydrolysis of solution at 100-105оС accompanied by distilling away HCl leads to residual HCl concentration 20-100 g/L. Distilled HCl is sent to processing of perovskite concentrate. Titanium-containing precipitate is separated from mother liquor, washed first with 15-37% HCl solution and then with water to pH 3. Washed precipitate is treated with aluminum acid phosphate with pH 2-4. Aluminum acid phosphate uptake (on conversion to Al2O3) constitutes 0.5 to 5.0% content of TiO2. Treated precipitate is separated and calcined at 850-870оС to give pigment titanium dioxide. From mother liquor (after separation of Ti-containing precipitate), radioactive components are isolated by 4-6-step extraction with tributyl phosphate. Organic phase-to-water phase ratio is (1.5-2.0):1. Degree of titanium recovery is at least 98%, whiteness at least 96.5 conv. units, brightening power 1650-1800 conv. units, spreading capacity 38.0-40.0 g/m2, oil capacity 25-27 g/100 g pigment. Yield of pigment TiO2 is 95.7-98.0%. Amount of radioactive precipitate does not exceed 0.06 kg.

EFFECT: optimized perovskite concentrate processing parameters.

12 cl, 4 ex

FIELD: catalyst preparation methods.

SUBSTANCE: catalyst containing crystalline anatase phase in amount at least 30% and nickel in amount 0.5 to 2% has porous structure with mean pore diameter 2 to 16 nm and specific surface at least 70 m2/g. When used to catalyze photochemical reaction of isolation of hydrogen from water-alcohol mixtures, it provides quantum yield of reaction 0.09-0.13. Preparation of titanium dioxide-based mesoporous material comprises adding titanium tetraalkoxide precursor and organic-nature template to aqueous-organic solvent, ageing reaction mixture to complete formation of spatial structure therefrom through consecutive sol and gel formation stages, separating reaction product, and processing it to remove template. Invention is characterized by that water-alcohol derivative contains no more than 7% water and template consists of at least one ligand selected from group of macrocyclic compounds, in particular oxa- and oxaazamacrocyclic compounds containing at least four oxygen atoms, and/or complexes of indicated macrocyclic compounds with metal ions selected from group of alkali metals or alkali-earth metal metals, or f-metals consisting, in particular, of lithium, potassium, sodium, rubidium, cesium, magnesium, calcium, strontium, barium, lanthanum, and cerium used in amounts from 0.001 to 0.2 mole per 1 mole precursor. Sol is formed by stirring reaction mixture at temperature not higher than 35°C. Once formation of spaced structure completed, mixture is held at the same temperature in open vessel to allow free access of water steam and, when template is removed from the mixture, mixture is first treated with nickel salt solution and then with alkali metal borohydride solution until metallic nickel is formed.

EFFECT: increased sorption and photocatalytic properties of catalyst and enabled reproducibility of its property complex.

7 cl, 68 ex

FIELD: production of inorganic compounds.

SUBSTANCE: invention relates to production of titanium dioxide using chloride process , which is employed in radio-electronic industry to manufacture multiple types of composite ceramic materials and also employed as starting material from production of metal titanates. Synthesis of titanium dioxide having high-purity rutile modification involves thermal hydrolysis of titanium tetrachloride solution with concentration 60-70 g/dm3 TiO2 and containing titanium nuclei and polyacrylamide in amount 100-120 g per 1 kg TiO2 in initial solution. Hydrolysis is continued for 1.5-2 h, after which resulting titanium hydroxide is separated from filtrate, treated with 2-3% oxalic acid solution, then with distilled water, dried and calcined at 550-650°C.

EFFECT: reduced hydrolysis process time, accelerated filtration, reduced consumption of power on heat treatment of resulting precipitate, and reduced negative environmental impact.

1 dwg, 1 tbl, 11 ex

FIELD: chemical industry; methods of production of the catalytic agents of photochemical reaction and sorbents-catalysts of heterogeneous photochemical processes.

SUBSTANCE: the invention is pertaining to the field of chemical industry and may be used in production of the catalytic agents of photochemical reaction and the sorbents-catalysts of heterogeneous photochemical processes of oxidizing of the harmful organic compounds. The precursor in the form of titanium tetraalcoxide and template of the organic nature are introduced into the water-organic dissolvent. The mixture of the reactants is intermixed up to formation of the sol and is kept till the final formation of the special structure. The gained reaction product is separated and treated removal of the template using calcifying or the extraction by the alcohol after preliminary hydrothermal treatment. In preferential version of the invention the water-alcohol dissolvent is additionally introduced with the salt of lanthanum. The invention allows to produce the reproducible sorbent-photocatalyst with the high attributes: the crystal phase of the anatase - no less than 30 mass %, a mean diameter of the pores - 2-16 nanometers, the specific surface - no less than 70 m2/g, does not contain the non-desirable impurities.

EFFECT: the invention ensures production of the reproducible sorbent-photocatalyst with the high attributes of thee crystal phase of the anatase, the effective diameter of the pores, the specific surface at absence of the non-desirable impurities.

7 cl, 68 ex

FIELD: sulfate method of production of titanium dioxide from titanium-containing material.

SUBSTANCE: proposed method includes leaching-out of titanium-containing materials with sulfuric acid solution for obtaining lye, deposition of ferrous sulfate from lye, extraction of titanyl sulfate from lye by means of solvent, hydrolysis of extracted titanyl sulfate followed by roasting of solid phase obtained at hydrolysis stage. At least part of raffinate from extraction stage is used as part of leaching solution at initial leaching-out stage.

EFFECT: high degree of purity of titanium dioxide; reduced amount of acid; reduced power requirements.

20 cl, 2 dwg, 9 tbl, 13 ex

FIELD: industrial inorganic synthesis.

SUBSTANCE: invention relates to a sulfate process for titanium dioxide production from titanium-containing material. Process comprises leaching starting material to produce leaching lye containing acidic solution of titanyl sulfate, which is separated from the lye and then hydrolyzed to form hydrated titanium oxides further fired to produce desired titanium dioxide. Hydrolysis step is properly controlled to form hydrated titanium oxides with desired particle size distribution.

EFFECT: enhanced commercial process efficiency.

29 cl, 2 dwg, 9 tbl, 13 ex

FIELD: sulfate method of production of titanium dioxide from titanium-containing material.

SUBSTANCE: proposed method includes leaching-out of titanium-containing material by sulfuric acid solution, thus obtaining lye containing titanyl sulfate, separation of titanyl sulfate from lye, hydrolysis of titanyl sulfate for forming solid phase containing hydrated titanium oxides followed by roasting the solid phase obtained at the hydrolysis stage. Proposed method includes additional leaching-out stage for leaching-out of solid phase remaining after leaching-out of initial titanium-containing material by means of solution containing sulfuric acid.

EFFECT: enhanced efficiency of process.

24 cl, 2 dwg, 9 tbl, 13 ex

FIELD: light-sensitive catalysts.

SUBSTANCE: invention is directed to preparation of titanium dioxide-based catalysts for photocatalytic treatment of water and air polluted with organics and pathogenic floras. Invention provides a method comprising preparation of reaction solution containing mineral titanium salt, fluoride ion, and activation additive; hydrolysis of mineral titanium salt to form precipitate; washing and calcination of the precipitate. Activation additive utilized is ammonium hydroxide in 5-10% stoichiometric excess. Hydrolysis is conducted for 0.25-0.5 h at pH 10-13, while concentration of fluoride ion in reaction solution is maintained at least 5 wt % based on TiO2. Mineral titanium salt is selected from titanium tetrachloride, titanyl sulfate, and titanium-ammonium chloride.

EFFECT: increased degree of recovering titanium dioxide into target product, increased heat resistance and specific surface of photocatalytic anatase-modification titanium, and reduced process duration.

6 cl, 1 tbl, 14 ex

FIELD: chemistry.

SUBSTANCE: invention can be applied in production of rutile-structured pigment based on titanium dioxide. The method of obtaining the base for pigment rutile titanium dioxide involves obtaining of source solution containing a titanium compound, addition of effective quantity of a salt catalyst to that solution, preferable addition of a chemical control agent to the solution, solution evaporation for obtaining dry amorphous intermediary product containing a mixture of titanium compounds, and baking of the intermediary product at the temperature under 500°C. Another variant of the method of obtaining the base for pigment rutile titanium dioxide uses eutectic mix of two or more NaCl, KCl and LiCl salts as the salt catalyst, melting temperature of the salt catalyst being lower than baking temperature.

EFFECT: reduction of rutile crystallisation temperature.

42 cl, 12 ex, 19 dwg

FIELD: nanotechnologies.

SUBSTANCE: invention is related to methods for production of nanosize particles of titanium dioxide, which may be used as photocatalysts, light sensitive materials of sun batteries, photo luminophors, as cathode materials of chemical current sources. Method for production of such particles of titanium dioxide includes hydrolysis of water solution that contains titanium ions, in presence of acid during heating. Water solution containing titanium ions is produced by dissolution of titanium hydride or metal titanium in 37% hydrochloric or 96% sulfuric acid dissolved with water, accordingly, as 1:2 or 1:3.4, to obtain ratio of Ti+3 : Cl-, equal to 1:6, or Ti+3 : SO42-, equal to 1:3. Hydrolysis may be performed in presence of nickel chloride or cobalt chloride.

EFFECT: invention makes it possible to simplify production of nanosize particles of titanium dioxide of different shape - in the form of nanobars, nanorods, nanoneedles, without negative effect at environment.

4 dwg, 7 ex

Up!