Novel method of producing silicon dioxide

FIELD: chemistry.

SUBSTANCE: invention is intended for chemical industry and can be used for making substrates for catalysts, absorbents, agents against caking or increasing viscosity of structure, additives to dental pastes and paper, fillers for polymer compositions. First, raw material containing water with pH of 2–5 is made and simultaneously silicate and diluted acid are added to it. After achieving congelation point concentrated acid is added to maintain specified value of pH. Then adding of concentrated acid is stopped, adding of silicate is continued. After achieving pH 7–10 silicate and acid are simultaneously added again to maintain specified value of pH. Then adding of silicate is stopped, continuing to add acid to bring pH less than 6. Obtained suspension of silicon dioxide is separated and dried by spraying.

EFFECT: invention reduces power consumption and increases efficiency of production of fine-grained silicon dioxide, while preserving all its properties and characteristics.

17 cl, 2 ex

 



 

Same patents:

FIELD: chemistry.

SUBSTANCE: invention relates to novel granular silicic acids for use as catalyst supports, production and use thereof. Disclosed is a granular silicic acid with defined mercury porosimetry with pore volume (less than 4 mcm) greater than 0.90 ml/g, dQ3=10% greater than 400 mcm and dQ3=90% less than 3000 mcm and the ratio of the value d50 without ultrasonic action to the value d50 after 3-minute ultrasonic action of less than 4.00, wherein measurements are taken on a particle fraction with size ranging from 400 to 500 mcm. Also disclosed are versions of the method of producing said acid, use thereof, an absorbate based thereon and a method for production thereof, as well as use of the obtained absorbate.

EFFECT: disclosed acids enable to obtain catalysts supports that are resistant to mechanical action, which lead to minimally possible loss of pressure of a reaction mixture passing through fixed-bed reactors.

20 cl, 2 tbl, 7 ex

FIELD: chemistry.

SUBSTANCE: invention relates to the chemical industry and can be used in manufacturing substrates for catalysts, absorbing agents of active substances, thickening agents, anti-caking agents, additives to toothpastes and paper. The method of obtaining precipitated silicon oxide includes the reaction of precipitation between silicate and at least one acid with a concentrated acid, selected from the group, consisting of sulphuric acid with the concentration of at least 80 wt %, acetic acid or formic acid with the concentration of at least 90 wt %, nitric acid with the concentration of at least 60 wt %, phosphoric acid with the concentration of at least 75 wt %, hydrochloric acid with the concentration of at least 30 wt %. The obtained suspension of precipitated silicon oxide is separated by filtration, the residue is milled in the presence of an alkali metal aluminate and dried by sputtering.

EFFECT: invention makes it possible to obtain precipitated silicon oxides with the physical-chemical characteristics, close to the known ones, with the reduction of an amount of consumed energy and water.

12 cl, 4 ex

FIELD: chemistry.

SUBSTANCE: invention relates to use of silicic acids in rubber mixtures used to produce various industrial rubber articles. The invention includes a method of producing precipitated silicic acids, characterised by a maximally narrow and uniform particle size distribution coupled with optimum pore size distribution, as well as use of said silicic acids as filler for rubber mixtures.

EFFECT: invention provides reinforcement which is uniform in the entire rubber matrix, thereby improving wear resistance of the finished rubber article.

25 cl, 3 dwg, 6 tbl, 4 ex

FIELD: chemistry.

SUBSTANCE: claimed invention relates to suspensions, containing very small amount of salts and containing, at least, one precipitated silicon oxide. Claimed is method of obtaining suspensions which have low content of salts and include, at least, one precipitated silicon oxide, including the following stages: provision of suspension, containing, at least, one precipitated silicon oxide; bringing suspension pH to value 0.5-5, if pH of suspension, obtained at the previous state, is not in the said interval; purification of suspension by means of electrodialysis, with device for electrodialysis including one or more electrodialysis cells, in each of which product-containing area is separated from catholyte-containing area by means of cation-exchange membrane and distance between electrodes constitutes from 2 to 200 mm; and application of potential from 5 to 1000 V. Also claimed are: suspension obtained by said method, cell for electrodialysis and device which contains it, as well as suspension application. Obtained suspensions are suitable for obtaining coatings for paper in manufacturing information carriers with application of inkjet printing or for obtaining dried precipitated silicon oxides.

EFFECT: method makes it possible to obtain suspensions, containing precipitated silicon oxide with content of sodium sulphate lower than 1000 ppm.

21 cl, 1 tbl, 2 ex

FIELD: chemistry.

SUBSTANCE: invention can be applied in chemical industry. Precipitated silicon dioxide is obtained by interaction of alkali metal silicate and/or alkali earth metal silicate and acidifying reagent at temperature equal from 80 to 95°C, for from 60 to 90 min. After that, precipitated suspension is acidified and subjected to ageing for 5-50 minutes, filtered, washed and dried. Value Y, characterising concentration of alkali metal ion in reaction mixture solution, is supported for precipitated suspension at constant value, equal from 10 to 30, and deviates by not more than 3% from the initial Y value. Precipitated silicon dioxide has BET surface area from 185 to 260 m2/g; surface area, equal from 100 to 160 m2/g; BET/CTAB ratio, equal from 1.2 to 2.6; electric conductivity, equal less than 250 (µS); average size of particles d50, equal from 5 to 25 mcm; and tap density, equal from 50 to 150 g/l.

EFFECT: claimed silicon dioxide is suitable for application in compositions of silicone rubber RTV-1, RTV-2, HTV and LSR to thicken and strengthen compositions.

15 cl, 4 tbl

FIELD: chemistry.

SUBSTANCE: invention can be used in chemical industry. Precipitated silica is obtained by reacting a silicate with an acid agent. The precipitated silica is formed from aggregates of coarse primary silica particles, on the surface of which there are fine primary silica particles. The silica has: specific adsorption surface area CTAB (SCTAB) from 60 to 400 m2/g, an aggregate median size d50, measured by XDC grading after ultrasound deagglomeration, such that: d50 (nm) > (6214/SCTAB (m2/g))+23, pore volume distribution, such that: V(d5-d50)/V(d5-d100)>0.906-(0.0013×SCTAB (m2/g)), and pore size distribution, such that: mode (nm) > (4166/SCTAB(m2/g))-9.2. The silica is used as reinforcing filler for polymers.

EFFECT: novel method.

35 cl, 18 tbl, 2 dwg

FIELD: chemistry.

SUBSTANCE: invention can be used to obtain silicon dioxide dispersions. A dispersion of porous anionic particles of silicon dioxide with a modified surface contains a liquid and silicon dioxide particles. The maximum fractional filled volume (Fmax) of the said particles in the said liquid is at least 0.55 and can be calculated using formula , where F is the fractional filled volume of solid substances in the liquid, Fmax is asymptotic limit of the fractional filled volume while approaching infinity, b is intrinsic viscosity, η0 is viscosity of the liquid/solvent, η is viscosity of the dispersion. The dispersion is obtained by forming a suspension from silicon oxide particles and liquid with its subsequent grinding. The said suspension contains a chemical agent which increases the volume fraction of the particles in the dispersion. The invention also relates to a coating composition and a coating on a substrate which contains the said dispersion.

EFFECT: invention enables to obtain stable silicon dioxide dispersions with high content of solid substances.

31 cl, 2 tbl, 5 ex

FIELD: chemistry.

SUBSTANCE: invention can be used in the tyre industry, rubber industry, in the production of plastic, glass, cement, lacquer, resins and pesticides. An initial sodium silicate solution with density 1.06-1.07 g/cm3 is mixed with a silica-containing inoculant - a product of direct precipitation of 12-31% hydrochloric acid from the sodium silicate solution with density 1.08-1.12 g/cm3. The reaction mixture, which consists of the silica-containing inoculant and the sodium silicate solution, is carbonised with carbon dioxide to form a silicon dioxide precipitate and the carbonised suspension is neutralised with 12-31% hydrochloric acid to pH 2.9-6.5. The obtained silicon dioxide precipitate is filtered, washed and dried.

EFFECT: obtaining silica with specific surface area of 120-170 m2/g and packed density of 232-244 g/dm3 and simplifies the production process.

3 cl, 1 tbl, 3 ex

FIELD: chemistry of polymers, chemical technology.

SUBSTANCE: invention relates to a method for preparing a filling agent used in manufacturing polymeric composition materials in making articles for structural and tribotechnical designation. Method involves mixing 0.5-10.0 mas. p. of epoxy diane resin with 100.0 mas. p. of sodium silicate aqueous solution (by dry matter) at temperature 40-60°C. Then the mixture is coagulated with mineral acid taken in the amount providing hydrogen index pH = 4.0-5.0, washed out with water and prepared solid substance as a precipitate is dried. Invention provides enhancing physicochemical and antifriction properties of the polymeric composition.

EFFECT: improved preparing method.

5 ex

FIELD: technology for silicium dioxide production useful as additive for polymer reinforcement.

SUBSTANCE: claimed method includes silicate reaction with acidifying agent to produce silicium dioxide slurry separation and drying of said slurry, wherein reaction is carried out according to the next steps: i) providing base aqueous solution with pH from 2 to 5, preferably from 2.5 to 5; ii) simultaneous addition silicate and acidifying agent to said base solution maintaining solution pH from 2 to 5, preferably from 2.5 to 5; iii) addition silicate only without acidifying agent to produce pH from 7 to 10, preferably from 7.5 to 9.5; (iv) simultaneous addition silicate and acidifying agent to reaction medium to maintain pH from 7 to 10, preferably from 7.5 to 9.5; (v) addition acidifying agent only without silicate to produce reaction medium pH below 6. Obtained high structured silicium dioxides have the next characteristics: CTAB specific surface (SCTAB) is 40-525 m2/g; BET specific surface (SBET) is 45-550 m2/g; width Ld ((d84-d16)/d50) of particle size distribution measured by XDC grading analysis after ultrasound grinding is at least 0.92; and such pore distribution that V(d95-d50)/V(d5-d100) is at least 0.66.

EFFECT: improved material for polymer reinforcement.

FIELD: technology for silicium dioxide production useful as additive for polymer reinforcement.

SUBSTANCE: claimed method includes silicate reaction with acidifying agent to produce silicium dioxide slurry separation and drying of said slurry, wherein reaction is carried out according to the next steps: i) providing base aqueous solution with pH from 2 to 5, preferably from 2.5 to 5; ii) simultaneous addition silicate and acidifying agent to said base solution maintaining solution pH from 2 to 5, preferably from 2.5 to 5; iii) addition silicate only without acidifying agent to produce pH from 7 to 10, preferably from 7.5 to 9.5; (iv) simultaneous addition silicate and acidifying agent to reaction medium to maintain pH from 7 to 10, preferably from 7.5 to 9.5; (v) addition acidifying agent only without silicate to produce reaction medium pH below 6. Obtained high structured silicium dioxides have the next characteristics: CTAB specific surface (SCTAB) is 40-525 m2/g; BET specific surface (SBET) is 45-550 m2/g; width Ld ((d84-d16)/d50) of particle size distribution measured by XDC grading analysis after ultrasound grinding is at least 0.92; and such pore distribution that V(d95-d50)/V(d5-d100) is at least 0.66.

EFFECT: improved material for polymer reinforcement.

FIELD: chemistry of polymers, chemical technology.

SUBSTANCE: invention relates to a method for preparing a filling agent used in manufacturing polymeric composition materials in making articles for structural and tribotechnical designation. Method involves mixing 0.5-10.0 mas. p. of epoxy diane resin with 100.0 mas. p. of sodium silicate aqueous solution (by dry matter) at temperature 40-60°C. Then the mixture is coagulated with mineral acid taken in the amount providing hydrogen index pH = 4.0-5.0, washed out with water and prepared solid substance as a precipitate is dried. Invention provides enhancing physicochemical and antifriction properties of the polymeric composition.

EFFECT: improved preparing method.

5 ex

FIELD: chemistry.

SUBSTANCE: invention can be used in the tyre industry, rubber industry, in the production of plastic, glass, cement, lacquer, resins and pesticides. An initial sodium silicate solution with density 1.06-1.07 g/cm3 is mixed with a silica-containing inoculant - a product of direct precipitation of 12-31% hydrochloric acid from the sodium silicate solution with density 1.08-1.12 g/cm3. The reaction mixture, which consists of the silica-containing inoculant and the sodium silicate solution, is carbonised with carbon dioxide to form a silicon dioxide precipitate and the carbonised suspension is neutralised with 12-31% hydrochloric acid to pH 2.9-6.5. The obtained silicon dioxide precipitate is filtered, washed and dried.

EFFECT: obtaining silica with specific surface area of 120-170 m2/g and packed density of 232-244 g/dm3 and simplifies the production process.

3 cl, 1 tbl, 3 ex

FIELD: chemistry.

SUBSTANCE: invention can be used to obtain silicon dioxide dispersions. A dispersion of porous anionic particles of silicon dioxide with a modified surface contains a liquid and silicon dioxide particles. The maximum fractional filled volume (Fmax) of the said particles in the said liquid is at least 0.55 and can be calculated using formula , where F is the fractional filled volume of solid substances in the liquid, Fmax is asymptotic limit of the fractional filled volume while approaching infinity, b is intrinsic viscosity, η0 is viscosity of the liquid/solvent, η is viscosity of the dispersion. The dispersion is obtained by forming a suspension from silicon oxide particles and liquid with its subsequent grinding. The said suspension contains a chemical agent which increases the volume fraction of the particles in the dispersion. The invention also relates to a coating composition and a coating on a substrate which contains the said dispersion.

EFFECT: invention enables to obtain stable silicon dioxide dispersions with high content of solid substances.

31 cl, 2 tbl, 5 ex

FIELD: chemistry.

SUBSTANCE: invention can be used in chemical industry. Precipitated silica is obtained by reacting a silicate with an acid agent. The precipitated silica is formed from aggregates of coarse primary silica particles, on the surface of which there are fine primary silica particles. The silica has: specific adsorption surface area CTAB (SCTAB) from 60 to 400 m2/g, an aggregate median size d50, measured by XDC grading after ultrasound deagglomeration, such that: d50 (nm) > (6214/SCTAB (m2/g))+23, pore volume distribution, such that: V(d5-d50)/V(d5-d100)>0.906-(0.0013×SCTAB (m2/g)), and pore size distribution, such that: mode (nm) > (4166/SCTAB(m2/g))-9.2. The silica is used as reinforcing filler for polymers.

EFFECT: novel method.

35 cl, 18 tbl, 2 dwg

FIELD: chemistry.

SUBSTANCE: invention can be applied in chemical industry. Precipitated silicon dioxide is obtained by interaction of alkali metal silicate and/or alkali earth metal silicate and acidifying reagent at temperature equal from 80 to 95°C, for from 60 to 90 min. After that, precipitated suspension is acidified and subjected to ageing for 5-50 minutes, filtered, washed and dried. Value Y, characterising concentration of alkali metal ion in reaction mixture solution, is supported for precipitated suspension at constant value, equal from 10 to 30, and deviates by not more than 3% from the initial Y value. Precipitated silicon dioxide has BET surface area from 185 to 260 m2/g; surface area, equal from 100 to 160 m2/g; BET/CTAB ratio, equal from 1.2 to 2.6; electric conductivity, equal less than 250 (µS); average size of particles d50, equal from 5 to 25 mcm; and tap density, equal from 50 to 150 g/l.

EFFECT: claimed silicon dioxide is suitable for application in compositions of silicone rubber RTV-1, RTV-2, HTV and LSR to thicken and strengthen compositions.

15 cl, 4 tbl

FIELD: chemistry.

SUBSTANCE: claimed invention relates to suspensions, containing very small amount of salts and containing, at least, one precipitated silicon oxide. Claimed is method of obtaining suspensions which have low content of salts and include, at least, one precipitated silicon oxide, including the following stages: provision of suspension, containing, at least, one precipitated silicon oxide; bringing suspension pH to value 0.5-5, if pH of suspension, obtained at the previous state, is not in the said interval; purification of suspension by means of electrodialysis, with device for electrodialysis including one or more electrodialysis cells, in each of which product-containing area is separated from catholyte-containing area by means of cation-exchange membrane and distance between electrodes constitutes from 2 to 200 mm; and application of potential from 5 to 1000 V. Also claimed are: suspension obtained by said method, cell for electrodialysis and device which contains it, as well as suspension application. Obtained suspensions are suitable for obtaining coatings for paper in manufacturing information carriers with application of inkjet printing or for obtaining dried precipitated silicon oxides.

EFFECT: method makes it possible to obtain suspensions, containing precipitated silicon oxide with content of sodium sulphate lower than 1000 ppm.

21 cl, 1 tbl, 2 ex

FIELD: chemistry.

SUBSTANCE: invention relates to use of silicic acids in rubber mixtures used to produce various industrial rubber articles. The invention includes a method of producing precipitated silicic acids, characterised by a maximally narrow and uniform particle size distribution coupled with optimum pore size distribution, as well as use of said silicic acids as filler for rubber mixtures.

EFFECT: invention provides reinforcement which is uniform in the entire rubber matrix, thereby improving wear resistance of the finished rubber article.

25 cl, 3 dwg, 6 tbl, 4 ex

FIELD: chemistry.

SUBSTANCE: invention relates to the chemical industry and can be used in manufacturing substrates for catalysts, absorbing agents of active substances, thickening agents, anti-caking agents, additives to toothpastes and paper. The method of obtaining precipitated silicon oxide includes the reaction of precipitation between silicate and at least one acid with a concentrated acid, selected from the group, consisting of sulphuric acid with the concentration of at least 80 wt %, acetic acid or formic acid with the concentration of at least 90 wt %, nitric acid with the concentration of at least 60 wt %, phosphoric acid with the concentration of at least 75 wt %, hydrochloric acid with the concentration of at least 30 wt %. The obtained suspension of precipitated silicon oxide is separated by filtration, the residue is milled in the presence of an alkali metal aluminate and dried by sputtering.

EFFECT: invention makes it possible to obtain precipitated silicon oxides with the physical-chemical characteristics, close to the known ones, with the reduction of an amount of consumed energy and water.

12 cl, 4 ex

FIELD: chemistry.

SUBSTANCE: invention relates to novel granular silicic acids for use as catalyst supports, production and use thereof. Disclosed is a granular silicic acid with defined mercury porosimetry with pore volume (less than 4 mcm) greater than 0.90 ml/g, dQ3=10% greater than 400 mcm and dQ3=90% less than 3000 mcm and the ratio of the value d50 without ultrasonic action to the value d50 after 3-minute ultrasonic action of less than 4.00, wherein measurements are taken on a particle fraction with size ranging from 400 to 500 mcm. Also disclosed are versions of the method of producing said acid, use thereof, an absorbate based thereon and a method for production thereof, as well as use of the obtained absorbate.

EFFECT: disclosed acids enable to obtain catalysts supports that are resistant to mechanical action, which lead to minimally possible loss of pressure of a reaction mixture passing through fixed-bed reactors.

20 cl, 2 tbl, 7 ex

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