Novel method of obtaining precipitated silicon oxides

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

 

The invention relates to a new method of obtaining the deposited silicon oxide.

Is known about the use of precipitated silica as catalyst substrates, as a scavenger of active substances (in particular, fillers liquids, such as used in the diet, such as vitamins (particularly vitamin E), line: choline chloride), as thickening agents, improvers consistency or funds from caking as item separators for batteries, as an additive to toothpaste, paper.

Precipitated silica can also be used as reinforcing fillers in silicone matrices (for example, for coating electrical cables) or compositions based on synthetic or natural polymers, in particular elastomers, in particular diene, for example, for tires, Shoe soles, floor coverings, gas-tight barriers, fire-resistant materials for impregnation, and also for such technical details as the pulleys for the cable cars, the connections for electrical appliances, pipe joints in pipelines for liquid or gas seal for the brake system (flexible) hoses, membranes, cables and drive belts.

There are known some methods of preparation, which is carried out the deposition reaction between the silicate and dilute acid, and aside�nye silicon oxides have good ability of dispersion (dispersibility) in the polymer (elastomer) compositions and good ability of dispersion (dispersibility) in the polymer (elastomer) compositions and good reinforcing properties, allowing to achieve in these compositions, in which they were introduced, a very satisfactory compromise of properties, in particular with regard to their mechanical, rheological and/or dynamic properties.

The main objective of the present invention is to propose a new method of producing precipitated silica, suitable for use as a reinforcing filler in the polymer (elastomer) compositions, which would represent an alternative to known methods of producing precipitated silica.

More preferably, one of the objectives of the present invention is to develop a method that, with improved efficiency, in particular in relation to the deposition reaction, in particular, compared to the extraction methods according to the prior art, in which the acid used is dilute acid, allows to obtain a precipitated silica, having physico-chemical characteristics and properties, in particular with regard to their distribution within the pores, their ability to desagglomeration and dispersion (dispersibility) in the polymer (elastomer) compositions and/or reinforcing properties, close to the characteristics and properties of the precipitated silica obtained by the methods of obtaining commensurate with level of technology.

In particular, for this purpose, the object of the invention is a new method of obtaining the deposited oxide of silicon, preferably having a good ability of dispersion (dispersibility) in the polymer (elastomer) compositions and good reinforcing properties, including the deposition reaction between the silicate and at least one acid, to thereby produce a suspension of precipitated silica, then separating and drying that suspension, in which:

- the reaction of the deposition, according to the following sequential steps:

(i) form of the original batch containing a silicate and an electrolyte, and the concentration of silicate (expressed on SiO2) in the specified source kneading above 0 g/l and below 100 g/l and, preferably, the concentration of the electrolyte in the specified source kneading greater than 0 g/l and less than 19 g/l, in particular below 18 g/l, in particular below 17 g/l, for example, below 15 g/l (being often above 6 g/l),

(ii) adding acid to the specified batch to achieve the pH of the reaction medium of at least 7, in particular from 7 to 8.5,

(iii) simultaneously added to the reaction medium�the acid and silicate,

(iv) adding to the reaction medium acid, in particular, to obtain the pH of the reaction medium in the range from 3.0 to 6.5, in particular from 4.0 to 5.5,

- slurry, preferably having a solids content of not more than 24 wt.%, dried;

moreover, the acid used at least in step (iii) is a concentrated acid, preferably concentrated sulfuric acid, i.e. sulfuric acid having a concentration of at least 80 wt.%, preferably at least 90% of the mass.

Thus, according to one of the essential characteristics of the invention, in combination with the sequence of stages in the special conditions, in particular, at a certain concentration of the silicate and of the electrolyte in the initial batch, as well as, preferably, with proper solids content in the slurry, which was dried, the acid used in the step (iii) is a concentrated acid, preferably concentrated sulfuric acid, i.e. sulfuric acid having a concentration of at least 80% of the mass. (and usually not more than 98 mass%), preferably at least 90% wt.; in particular, its concentration ranges from 90 to 98 wt.%, for example, from 91 to 97% of the mass.

Then the acid used in steps (ii) and (iv) may be, for example, dilute acid, preferably dilute sulfuric acid, that is, they�setup portion of the much lower concentration of 80 wt.%, in this case, the concentration below 20 wt%. (and usually at least 4%), in particular, below 14 wt.%, in particular, not more than 10 wt.%, for example, from 5 to 10 wt%.

However, according to one very preferred embodiment of the invention, the acid used in step (iv) is also concentrated acid which is indicated above.

Although in a very preferred variant of the invention, the acid used in the step (ii) may be, for example, dilute acid, as described above, in this embodiment of the invention may be advantageous that the acid used on the side of the stage (ii), usually on the second and last part of this phase (ii) was also concentrated acid which is indicated above (wherein the acid used in another part of the stage (ii) is, for example, dilute acid, as described above). So, at this stage, (ii) the acid used to reach the point of gelation in the reaction medium (corresponding to a sharp increase in turbidity of the reaction medium, which is characteristic for increasing the size of the objects) can be diluted with the acid, what is stated above, preferably dilute sulfuric acid (i.e., having a much lower concentration of 80 wt.%, in this case, the concentration below 20 wt.%, usually below 14 wt.%, in particular, not more than 10 wt.%, for example, in the range from 5 to 10 wt%.), and �Isleta, used after reaching the point of gelation in the reaction medium, can be concentrated acid, what is stated above, preferably concentrated sulfuric acid, i.e. sulfuric acid having a concentration of at least 80 wt.%, preferably at least 90 wt.%, in particular, from 90 to 98 wt%. Similarly, at this stage, (ii) the acid used in the first x minutes of stage (ii), where x is from 15 to 25, for example, equal to 20, can be diluted with the acid, what is stated above, and the acid used after the first x minutes of stage (ii), where x is from 15 to 25, for example, is 20 may be concentrated acid which is indicated above.

In a very preferred variant of the invention, the acid used in the step (ii) may also be concentrated acid, what is stated above, that is, to have a concentration of at least 80 wt.%, preferably at least 90 wt.%, in particular, from 90 to 98 wt%. In the case of this application, you can optional add the water to the original batch, in particular, either before step (ii) or in phase (ii).

Preferably, in the method according to the invention the concentration of silicate (expressed on SiO2) in the initial batch, which is below 100 g/l may be at least 80 g/L. Thus, it is possible, in particular, to hang out in the framework described above is very preferred variant of the invention (concentrated acid, used at all stages (iii) and (iv)), when part of the stage (ii) is not carried out with concentrated acid.

Although this is not necessarily the preferred implementation of the method according to the invention, the concentration of silicate (expressed as SiO2in an initial batch may be below 80 g/L. Thus, it is possible, in particular, to stay within the framework described above is very preferred variant of the invention (concentrated acid used at all stages (iii) and (iv)), when the entire stage (ii) is a concentrated acid.

In the method according to the invention as acid (concentrated acid or dilute acid) is commonly used organic acid, such as acetic acid, formic acid or carbonic acid, or, preferably, an inorganic acid, such as sulfuric acid, nitric acid, phosphoric acid or hydrochloric acid.

If concentrated acid is used, the concentrated acetic acid or concentrated formic acid, its concentration is at least 90% of the mass.

If concentrated acid is used concentrated nitric acid, its concentration is at least 60% of the mass.

If concentrated acid is used concentrated FOS�ornago acid, its concentration is at least 75% of the mass.

If concentrated acid is used concentrated hydrochloric acid, its concentration is at least 30% of the mass.

However, it is preferable to use the acid is sulfuric acid, and then used concentrated sulfuric acid has a concentration which has already been described above.

Can furthermore be used as silicate with any conventional form of silicate, such as metasilicates, disilicate, and preferably the alkali metal silicate, particularly sodium silicate or potassium.

The silicate may have a concentration (expressed as SiO2) in the range from 40 to 330 g/l, for example, from 60 to 300 g/L.

It is preferable to use as silicate sodium silicate.

In the case when using sodium silicate, it is usually present in a weight ratio SiO2/Na2O, lying in the interval from 2 to 4, in particular from 2.4 to 3.9, for example, from 3.1 to 3.8.

As for the electrolyte contained in the initial batch (stage (i)), the term is understood here in its ordinary accepted meaning, i.e. it means any ionic or molecular substance which, when it is in solution, decomposes or dissociates, forming ions or charged particles. The electrolyte can�VAT salt from the group of salts of alkali and alkaline earth metals, in particular, a metal salt of a source of silicate and acid, e.g., sodium chloride in the case of the reaction of sodium silicate with hydrochloric acid or, preferably, sodium sulfate in the case of the reaction of sodium silicate with sulfuric acid.

Adding acid in step (ii) leads to a corresponding decrease in pH of the reaction medium, and it is carried out until the pH of the reaction medium of at least 7, in particular lying in the range from 7 to 8.5, for example, from 7.5 to 8.5.

After the desired pH value are transferred to the simultaneous addition of stage (iii).

This simultaneous addition is usually carried out so that the pH value of the reaction medium was constant (±0,1) and equal to achieved at the end of phase (ii).

After step (iv) can proceed to the maturation of the obtained reaction medium (aqueous suspension), at pH obtained at the outlet of stage (iv), and usually with stirring, for example for from 2 to 45 minutes, in particular within 3-30 minutes.

Stages (i) to(iv) is usually carried out with stirring.

Similarly, all of the steps (i) to(iv) is usually conducted at a temperature of from 75 to 97°C, preferably from 80 to 96°C.

According to one embodiment of the invention, stage (ii) is carried out (all or part) or not carried out with concentrated acid, and the temperature at the end of reaction is higher than the temperature in the early�e reaction thus, the temperature at the beginning of the reaction (for example, in phase (i) and part of step (ii)) is preferably maintained at from 75 to 90°C, then the temperature was raised, preferably to a value in the range from 90 to 97°C and kept at this value (for example, during a portion of step (ii) and during steps (iii) and (iv)) until the end of the reaction.

According to another embodiment of the invention, for example (but not exclusively) when part of the stage (ii) is not carried out with concentrated acid, all of the steps (i) to(iv) may be maintained at a constant temperature.

In the method of the invention at the outlet of stage (iv), which may be maturity, receive the slurry of silicon oxide, which is then subjected to separation (separation of liquid-solid).

This division usually includes filtering (if necessary with some washing), carried out by any suitable method, for example, on a belt filter, a vacuum filter or, preferably, on a filter press.

Usually this division includes after filtration, grinding, and the specified reduction can then be carried out in the presence of at least one compound of aluminum and, possibly, in the presence of acid (in this latter case, the bonding of aluminum and the specified acid is preferably added at the same time).

The grinding operation which can be performed mechanically, for�reamer, by carrying out the filtration of the precipitate through a crusher type colloid mill or ball mill, allows, in particular, to reduce the viscosity of the suspension, which will later be dried (in particular, spraying).

The connection usually consists of aluminum of alkali metal aluminate, in particular, potassium or preferably sodium.

Collected in this way a suspension of precipitated silica (filter cake, normally shredded) and then dried.

Preferably, in the method of receiving according to the invention, this suspension should be directly in front of his drying solids content of not more than 24 wt.%, in particular, no more than 23% vol., for example, not more than 22% of the mass.

This drying may be carried out by any known method.

Preferably, drying is performed by spraying. You can use any suitable type of atomizer, in particular, turbine, nozzle sprayer, sprayer with hydraulic pressure or two-fluid atomizer. Usually, when the filtration is carried out using a filter press, uses a jet spray, and when the filtration is carried out using a vacuum filter, used turbine sprayer.

When drying is carried out using a spray atomizer, precipitated silica, which can then be obtained, is in the form of �about the merits of spherical grains.

After exiting the drying optionally, you can proceed to the stage of grinding the harvested product; precipitated silica, which can then be obtained, is usually in powder form.

When drying is carried out using a turbine atomizer, precipitated silica, which can then be obtained, is usually in powder form.

Finally, dried (in particular, turbine spray or crushed product as indicated above, can optionally be subjected to an agglomeration stage, which consists, for example, in direct compaction, wet granulation (i.e. using a binder, such as water, a suspension of silicon oxide, etc.), extrusion or, preferably, dry compacting. When using this last method, it may be favorable prior to pressing to carry out deaeration (surgery, also called predoplatnoj or degassing) powder products to remove included them in the air and to ensure a more even compressible.

The precipitated silica which can be obtained at this stage of agglomeration, is usually in the form of granules.

The implementation of the method of receiving according to the invention, especially when used concentrated acid is concentrated sulfuric acid, allows, in particular, to provide during account creation during�way (output from step (iv)) the slurry with a higher concentration of precipitated silica than is obtained in an identical way, using only dilute acid, and, thus, to obtain a higher yield on beleaguered silicon oxide (which may be achieved, for example, at least 10-40%), in particular, on the reaction of deposition (i.e., at the outlet of stage (iv)) that are unexpectedly accompanied by the production of precipitated silica, having a good ability of dispersion (dispersibility) in the polymer (elastomer) compositions; more General, precipitated silica obtained by the method according to the invention, preferably have physico-chemical characteristics and properties in particular, in relation to their distribution within the pores, their ability to desagglomeration and dispersion (dispersibility) in the polymer (elastomer) compositions and/or reinforcing properties, comparable with the characteristics and properties of the precipitated silica obtained in an identical way, using only dilute acid.

At the same time, preferably, in particular when used concentrated acid is concentrated sulfuric acid, the method of the invention allows to obtain in comparison with the identical way, using only dilute acid, the gain (which may be achieved, for example, at least 20-60%) in power consumption (e.g., in the form �strictly pair) in particular, the deposition reaction (that is, the output from step (iv)), by reducing the amount of water used and ekzotermicheskie related to the use of concentrated acid. Furthermore, the use of concentrated acid allows you to limit (e.g., at least 25%) of the amount of water required for the reaction, in particular, by reducing the amount of water used to prepare the acid.

Precipitated silica obtained by the method according to the invention, is preferably finely dispersed, i.e., in particular, he has a very high ability to desagglomeration and dispersion (dispersibility) in the polymer matrix, as can be seen, in particular, in electronic or optical microscopy on thin sections.

One of the parameters of the precipitated silica obtained by the method according to the invention, may be a distribution or division of its pore volume and, in particular, the distribution of the pore volume composed of pores with a diameter less than or equal to 400 Å. This latter volume corresponds to the volume of pores suitable for fillers used to reinforce elastomers. Analysis of porosity indicates that the oxide of silicon is usually preferably has such pore distribution, pore volume formed by pores whose diameter is � the range from 175 to 275 Å (V2), is at least 50%, particularly at least 60% of the pore volume formed by pores with a diameter less than or equal to 400 Å (V1).

The pore volumes and pore diameters measured by mercury porosimetry (Hg) using Porosimeter MICROMERITICS Autopore 9520 and calculate the ratio of WASHBURN when the angle of contact theta equal to 130° and a surface tension gamma equal to 484 Dyne/cm

The physical state in which the precipitated silica obtained by the method according to the invention, can be arbitrary, i.e., it may be in the form of microbasin (essentially spherical grains) of powder or granules.

So, it may be in the form of essentially spherical grains with an average size of at least 80 μm, preferably at least 150 μm, in particular in the range from 150 to 270 μm; the average size is defined according to the standard NF X 11507 (December 1970) by dry screening and determination of the diameter corresponding to the total sieve residue 50%.

It may be in the form of a powder with an average size of at least 3 μm, in particular at least 10 μm, preferably at least 15 microns.

It may be in the form of pellets (usually in the form of essentially parallelepiped) of size at least 1 mm, e.g. from 1 to 10 mm, in particular in the direction of their axes of greatest length.

When precipitated oxide cream�Oia, obtained by the method according to the invention is in the form of granules, it preferably has a pore distribution, pore volume formed by pores whose diameter is in the range from 175 to 275 Å (V2) is at least 60% of the pore volume formed by pores with a diameter less than or equal to 400 Å (V1).

Precipitated silica obtained by the method according to the invention, preferably has a specific surface of CTAB absorption in the range from 100 to 240 m2/g, in particular from 140 to 200 m2/g, e.g., from 140 to 180 m2/g.

Similarly, it preferably has a specific surface according to BET in the range from 100 to 240 m2/g, in particular from 140 to 200 m2/g, for example, from 150 to 190 m2/g.

Specific surface area by CTAB absorption is the outer surface, which can be defined by the method NF T 45007 (November 1987). Specific surface area by BET can be measured according to the method of brunauer-Emmett-teller described in "The Journal of The American Chemical Society", vol. 60, page 309 (1938), and the corresponding norm NF T 45007 (November 1987).

Ability of dispersion (and to desagglomeration) precipitated silica obtained by the method according to the invention can be evaluated in the next test by particle size measurement (by laser diffraction) carried out on suspensions of silicon oxide, the pre-desagglomeration�th ultrasound (rift objects to a particle size of 0.1 to several tens of microns). Desagglomeration ultrasound is performed using the ultrasonic irradiator VIBRACELL bioblock is used (750 W), equipped with a probe 19 mm. particle size measurement is carried out by laser diffraction on a SYMPATEC particle size indicator using theory of the Fraunhofer-Gesellschaft.

In a pillbox (height: 6 cm and diameter 4 cm), weigh out 2 grams of silicon oxide and Supplement to 50 grams by addition of permuteran water; thus, aqueous suspension with 4% of silicon oxide, which is homogenized for 2 minutes by stirring a magnetic stirrer. Then move to desagglomeration ultrasound as follows: the probe is immersed for a length of 4 cm, put it to work for 5 minutes and 30 seconds at 80% of nominal power (amplitude). Then subjected to particle size measurement, introducing a cell-volume V (expressed in ml) homogenizing suspension needed to obtain the optical density of the order of 20.

The value of the median diameter ø50in this test, the smaller the higher the ability of silicon oxide to desagglomeration.

The factor of desagglomeration FDis described by the equation:

FD= 10×V / (optical density of the suspension measured at a diffraction particle size analyzer) (this optical density is about 20).

The factor of desagglomeration FDcharacterizes to�Yu particles smaller than 0.1 µm, are not detected by diffraction particle size analyzer. This factor is higher, the greater the ability of silicon oxide to desagglomeration.

Usually, precipitated silica obtained by the method according to the invention, after disagglomeration ultrasound have a median diameter ø5Oless than 5 μm, in particular less than 4.5 μm, in particular less than 4 μm, such as less than 3 microns.

They typically have a coefficient of desagglomeration ultrasound FDhigher than 5.5 ml, in particular, above 6.5 ml, e.g., above 10 ml.

Its oil absorption (DOP) can be from 180 to 350 ml/100 g, in particular, in the case when it is in powder form. Oil absorption (DOP) can be determined according to the standard ISO 787/5 using dioctyl phthalate (DOP).

Precipitated silica obtained by the method according to the invention, can be used in multiple applications.

It can be applied, for example, as substrates of the catalyst as a scavenger of active substances (in particular, fillers liquids, for example, used in the diet, such as vitamins (vitamin E), line: choline chloride), polymer compositions, in particular, elastomeric, silicone, as thickening agents, improvers consistency or funds from caking as item separators for batteries, as an additive for toothpaste, for concrete, for paper.

However, he finds the person�but advantageous use for strengthening of polymers, natural or synthetic.

Polymer compositions in which it may be applied, in particular as reinforcing filler, are usually based one or more polymers or copolymers, in particular, one or more elastomers, preferably having at least one glass transition temperature, component from -150 to +300°C, for example, from -150 to +20°C.

As a possible polymers may be mentioned, in particular, diene polymers, in particular diene elastomers.

As non-limiting examples of finished products on the basis of these polymer compositions can be called Shoe soles, tires, floor coverings, gas barriers, refractory materials for impregnation, as well as such technical details as the pulleys for the cable cars, connectors for household appliances, pipe joints in pipelines for liquid or gas seal for the brake system (flexible) hoses, membranes (in particular, cables), cables, engine mount, belt, belts.

The following examples illustrate the invention but in no way limit its scope.

Example 1 (comparative)

In a stainless steel reactor equipped with a spiral mixing and heating with live steam in the reaction medium, enter:

- 637 litres in�s,

- 14,1 kg Na2SO4(electrolyte),

- 362 liters of an aqueous solution of sodium silicate having a weight ratio of SiO2/Na2O, equal to 3.5 and a density at 20°C, is $ 1,230.

The concentration of silicate (expressed as SiO2in the kneading equal in this case to 86 g/L. the Mixture is brought temperature 83°C, while continuing the stirring.

Then there is injected 462 liters of dilute sulfuric acid (density at 20°C, is $ 1,050 (sulfuric acid with a mass concentration equal to 7.7%). Dilute acid is introduced at a speed of 529 l/h for the first 20 minutes of reaction, then the rate of increase up to 1056 l/h until a pH of the reaction medium value of 8.0 (measured at ambient temperature).

Reaction temperature is 83°C during the first 20 minutes of the reaction; then it is brought from 83°C to 92°C for about 15 minutes, then maintained at 92°C until the reaction is finished.

Then to the reaction medium simultaneously administered 87,9 liters of an aqueous solution of sodium silicate of the type described above and 119 liters of sulfuric acid, also of the type described above, and the simultaneous introduction of dilute acid and silicate is carried out so that the pH of the reaction medium on the period of introduction all the time was $ 8,0±0,1.

After the introduction of silicate is continued for 6 minutes to introduce the diluted acid at a speed of 432 l/h.

It is an additional�th introduction acid brings the pH of the reaction medium to a value equal to 4.8.

The total duration of the reaction is 60 minutes.

Thus, the slurry of precipitated silica, which was filtered and washed on a filter press, so that at the end of the collected silicon oxide as filter cake, the moisture content of which amounts to 77% (i.e., solids content 23 mass%). This filter cake is then szhizhajut mechanical and chemical effects (adding a quantity of sodium aluminate corresponding to the weight ratio Al/SiO20,22%). After this operation the grinding get beyond pumping the filter the precipitate with a pH of 6.9, which is then sprayed using a spray nozzle.

Characteristics of the obtained (in the form of essentially spherical grains) of silicon oxide of the following:

Surface BET (m2/g)158
The surface of CTAB absorption (m2/g)155
ø50(µm)*2,1
FD(ml)*16,9
V2/V1 (%)57
*: after disaglomerated�and ultrasound

Example 2

In a stainless steel reactor equipped with a spiral mixing and heating with live steam in the reaction medium, enter:

700 liters of water,

- 15,5 kg Na2SO4(electrolyte),

- 402 liters of an aqueous solution of sodium silicate having a weight ratio of SiO2/Na2O, equal to 3.5 and a density at 20°C, is $ 1,230.

The concentration of silicate (expressed as SiO2in the kneading equal in this case to 86 g/L. the Mixture is brought temperature 83°C, while continuing the stirring.

Then there is injected 489 litres of dilute sulphuric acid (density at 20°C, is $ 1,050 (sulfuric acid with a mass concentration equal to 7.7%). Dilute acid is introduced at a speed of 546 l/h for the first 20 minutes of reaction, then the rate of increase up to 1228 l/h, until a pH of the reaction medium value of 8.0 (measured at ambient temperature).

Reaction temperature is 83°C during the first 20 minutes of reaction, then it was adjusted from 83°C to 92°C for about 15 minutes, then maintained at 92°C until the reaction is finished.

Then to the reaction medium simultaneously administered 98.0 liters of an aqueous solution of sodium silicate of the type described above and 6.5 liters of concentrated sulfuric acid (density at 20°C, equal to 1.83 (sulfuric acid with a mass concentration equal to 95%), and the simultaneous introduction of concentri�agreed acid and silicate is performed so as so that pH of the reaction medium on the period of introduction all the time was $ 8,0±0,1.

After the introduction of silicate is continued for 6 minutes to enter the concentrated acid at a rate of 20 l/h.

This is the introduction of additional acid brings the pH of the reaction medium to a value equal to 4.8.

The total duration of the reaction is 60 minutes.

Compared to example 1 is installed:

- improving the efficiency of the reaction (with respect to a final concentration expressed as SiO2in reaction medium and taking into account the duration of the reaction) by 11%,

- winning in the flow of water in the reaction 10%,

- the gain in energy in the reaction (in the form of steam) 10%.

Thus, the slurry of precipitated silica, which was filtered and washed on a filter press, so that at the end of the collected silicon oxide as filter cake, the moisture content of which amounts to 78% (i.e., the solids content of 22 mass%). This filter cake is then szhizhajut mechanical and chemical effects (adding a quantity of sodium aluminate corresponding to the weight ratio Al/SiO20,21%). After this operation the grinding get beyond pumping the filter the precipitate with a pH of 6.6, which is then sprayed using a spray nozzle.

Characteristics of the obtained (in view of� essentially spherical grains) of silicon oxide of the following:

Surface BET (m2/g)157
The surface of CTAB absorption (m2/g)155
ø50(µm)*2,5
FD(ml)*19,3
V2/V1 (%)60
*: after disagglomeration ultrasound

Example 3

In a stainless steel reactor equipped with a spiral mixing and heating with live steam in the reaction medium, enter:

- 860 liters of water

- 19,0 kg Na2SO4(electrolyte),

- 492 liters of an aqueous solution of sodium silicate having a weight ratio of SiO2/Na2O, equal to 3.5 and a density at 20°C, is $ 1,230.

The concentration of silicate (expressed as SiO2in the kneading equal in this case 86 g/L. the Mixture is brought to a temperature of 82°C, continuing to stir.

Then there is injected 232 liters of dilute sulfuric acid (density at 20°C, is $ 1,050 (sulfuric acid with a mass concentration equal to 7.7%) during the first 20 minutes of reaction, then 17 liters of concentrated sulfuric acid (density at 20°C, equal to 1.83 (sulfuric �Isleta with the mass concentration, equal to 95%), until a pH of the reaction medium value of 8.0 (measured at ambient temperature).

Reaction temperature is 82°C during the first 20 minutes of reaction, then it was adjusted from 82°C to 92°C for about 15 minutes, then maintained at 92°C until the reaction is finished.

Then to the reaction medium simultaneously administered 120 liters of an aqueous solution of sodium silicate of the type described above and 7.6 liters of concentrated sulfuric acid of the type described above, and the simultaneous introduction of concentrated acid and silicate is carried out so that the pH of the reaction medium on the period of introduction all the time was $ 8,0±0,1.

After the introduction of silicate is continued for 6 minutes to enter the concentrated acid at a rate of 23 l/h.

This is the introduction of additional acid brings the pH of the reaction medium to a value equal to 4.8.

The total duration of the reaction is 65 minutes.

Compared to example 1 is installed:

- improving the efficiency of the reaction (with respect to a final concentration expressed as SiO2in reaction medium and taking into account the duration of the reaction) at 25%,

- winning in the flow of water in the reaction 26%,

- the gain in energy consumption (in the form of steam) in the reaction of 32%.

Thus, the slurry of precipitated silica, which was filtered and washed on the filter�which represented a step backward, so in the end collect silicon oxide as filter cake, the moisture content of which amounts to 77% (i.e., solids content 23 mass%). This filter cake is then szhizhajut mechanical and chemical effects (adding a quantity of sodium aluminate corresponding to the weight ratio Al/SiO20,29%). After this operation the grinding get beyond pumping the filter the precipitate with a pH of 6.6, which is then sprayed using a spray nozzle.

Characteristics of the obtained (in the form of essentially spherical grains) of silicon oxide of the following:

Surface BET (m2/g)163
The surface of CTAB absorption (m2/g)160
ø50(µm)*2,5
FD(ml)*18,3
V2/V1 (%)61
*: after disagglomeration ultrasound

Example 4

In a stainless steel reactor equipped with a spiral mixing and heating jacket with double walls, enter:

- 86.4 liters of water

- 0,77 kg Na2SO4(electrolyte),

- 44,2 liter aqueous solution of sodium silicate having a weight ratio of SiO2/Na2O, equal to 3.5 and a density at 20°C, is $ 1,230.

The concentration of silicate (expressed as SiO2in the kneading equal in this case to 80 g/L. the Mixture is brought to the temperature of 87°C, while continuing the stirring. The temperature was maintained at this value throughout the reaction.

Then there is administered to 22.1 liters of dilute sulfuric acid (density at 20°C, is $ 1,050 (sulfuric acid with a mass concentration equal to 7.7%), during the first 20 minutes of reaction, then injected 1.46 liters of concentrated sulfuric acid (density at 20°C, equal to 1.85 (sulfuric acid with a mass concentration of 98%), until a pH of the reaction medium value of 8.0 (measured at ambient temperature).

Then to the reaction medium simultaneously administered 10.7 liters of an aqueous solution of sodium silicate of the type described above and a 0.69 liters of concentrated sulfuric acid of the type described above, and the simultaneous introduction of concentrated acid and silicate is carried out so that the pH of the reaction medium on the period of introduction all the time was $ 8,0±0,1.

After the introduction of silicate is continued for 6 minutes to enter a concentrated acid with a speed of 2.0 l/h.

This is in additional�edenia acid brings the pH of the reaction medium to a value equal to 4.8.

The total duration of the reaction is 60 minutes.

Compared to example 1 is installed:

- improving the efficiency of the reaction (with respect to a final concentration expressed as SiO2in reaction medium and taking into account the duration of the reaction) at 37%,

- winning in the flow of water in the reaction 27%,

- the gain in power consumption in the reaction of 32%.

Thus, the slurry of precipitated silica, which was filtered and washed using a vacuum filter, so in the end collect silicon oxide as filter cake, the moisture content of which is 85% (i.e., the solids content of 15% wt.). This filter cake is then szhizhajut mechanical and chemical effects (adding a quantity of sodium aluminate corresponding to the weight ratio Al/SiO20,27%). After this operation the grinding get beyond pumping the filter the precipitate with a pH of 6.8, which is then sprayed.

Characteristics of the obtained (in powder form) of silicon oxide of the following:

Surface BET (m2/g)155
The surface of CTAB absorption (m2/g)164
ø50(µm)* 2,8
FD(ml)*12,6
V2/V1 (%)58
*: after disagglomeration ultrasound

1. The method of producing a precipitated silica, comprising the deposition reaction between the silicate and at least one acid, to thereby produce a suspension of precipitated silica, then separating and drying that suspension, in which:
- the reaction of deposition is as follows:
(i) form of the original batch containing a silicate and an electrolyte, and the concentration of silicate (expressed as SiO2) in the specified source kneading below 100 g/l, and the concentration of the electrolyte in the specified source kneading is preferably below 19 g/l,
(ii) is added to the specified mixing acid to obtain a pH of the reaction medium of at least about 7.0, in particular in the range from 7 to 8.5,
(iii) are simultaneously added to the reaction medium acid and silicate,
(iv) adding acid to the reaction medium, in particular, to obtain a pH of the reaction medium in the range from 3.0 to 6.5,
- dry the slurry, preferably having a solids content of not more than 24 wt.%,
moreover, the acid used in at least step (iii) is a concentrated acid, an�Noah from the group consisting of sulfuric acid with a concentration of at least 80 wt.%, acetic acid or formic acid at a concentration of at least 90 wt.%, nitric acid with a concentration of at least 60 wt.%, phosphoric acid with a concentration of at least 75% wt., hydrochloric acid with a concentration of at least 30% of the mass.

2. A method according to claim 1, characterized in that the acid used in steps (iii) and (iv) is a concentrated acid selected from the group consisting of sulfuric acid with a concentration of at least 80 wt.%, acetic acid or formic acid at a concentration of at least 90 wt.%, nitric acid with a concentration of at least 60 wt.%, phosphoric acid with a concentration of at least 75% wt., hydrochloric acid with a concentration of at least 30% of the mass..

3. A method according to claim 2, characterized in that on the side of the stage (ii) of the acid used is a concentrated acid selected from the group consisting of sulfuric acid with a concentration of at least 80 wt.%, acetic acid or formic acid at a concentration of at least 90 wt.%, nitric acid with a concentration of at least 60 wt.%, phosphoric acid with a concentration of at least 75% wt., hydrochloric acid with a concentration of at least 30% of the mass.

4. A method according to claim 3, W�himself, in step (ii) acid used after reaching the point of gelation in the reaction medium is concentrated acid selected from the group consisting of sulfuric acid with a concentration of at least 80 wt.%, acetic acid or formic acid at a concentration of at least 90 wt.%, nitric acid with a concentration of at least 60 wt.%, phosphoric acid with a concentration of at least 75% wt., hydrochloric acid with a concentration of at least 30% of the mass.

5. Method according to one of claims. 3 and 4, characterized in that in step (ii) acid used after x minutes, measured from the start of this stage, and x ranges from 15 to 25, is a concentrated acid selected from the group consisting of sulfuric acid with a concentration of at least 80 wt.%, acetic acid or formic acid at a concentration of at least 90 wt.%, nitric acid with a concentration of at least 60 wt.%, phosphoric acid with a concentration of at least 75% wt., hydrochloric acid with a concentration of at least 30% of the mass.

6. Method according to one of claims. 1-4, characterized in that the concentration of silicate (expressed as SiO2) in the specified source kneading is at least 80 g/L.

7. A method according to claim 2, characterized in that the acid used in step (ii) is close�terouanne acid, selected from the group consisting of sulfuric acid with a concentration of at least 80 wt.%, acetic acid or formic acid at a concentration of at least 90 wt.%, nitric acid with a concentration of at least 60 wt.%, phosphoric acid with a concentration of at least 75% wt., hydrochloric acid with a concentration of at least 30% of the mass.

8. A method according to claim 7, characterized in that the concentration of silicate (expressed as SiO2) in the specified source kneading below 80 g/L.

9. Method according to one of claims. 1-4, characterized in that said concentrated acid is sulfuric acid having a concentration of at least 90% of the mass.

10. Method according to one of claims. 1-4, characterized in that said concentrated acid is sulfuric acid having a concentration in the range from 90 to 98% of the mass.

11. Method according to one of claims. 1-4, characterized in that the separation comprises a filtration and grinding filtration residue and the specified grinding is preferably carried out in the presence of at least one aluminum compounds, in particular alkali metal aluminate.

12. Method according to one of claims. 1-4, characterized in that the drying is performed by spraying.



 

Same patents:

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.

The invention relates to a technology for obtaining highly dispersed silicon dioxide and can be used in the chemical industry, in particular in the production of polymers and mineral fillers

The invention relates to amorphous silica used as abrasives in oral compositions, and method of production thereof

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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