US20110129401A1 - Production of precipitated silica employing a fast blender - Google Patents

Production of precipitated silica employing a fast blender Download PDF

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Publication number
US20110129401A1
US20110129401A1 US12/520,576 US52057607A US2011129401A1 US 20110129401 A1 US20110129401 A1 US 20110129401A1 US 52057607 A US52057607 A US 52057607A US 2011129401 A1 US2011129401 A1 US 2011129401A1
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silicate
reaction medium
acidifying agent
surface area
specific surface
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Elise Fournier
Jean-Claude Magne
Francois Nicol
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Rhodia Operations SAS
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Rhodia Operations SAS
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Assigned to RHODIA OPERATIONS reassignment RHODIA OPERATIONS ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: NICOL, FRANCOIS, FOURNIER, ELISE, MAGNE, JEAN-CLAUDE
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B33/00—Silicon; Compounds thereof
    • C01B33/113—Silicon oxides; Hydrates thereof
    • C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
    • C01B33/126—Preparation of silica of undetermined type
    • C01B33/128—Preparation of silica of undetermined type by acidic treatment of aqueous silicate solutions
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B33/00—Silicon; Compounds thereof
    • C01B33/113—Silicon oxides; Hydrates thereof
    • C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
    • C01B33/18—Preparation of finely divided silica neither in sol nor in gel form; After-treatment thereof
    • C01B33/187—Preparation of finely divided silica neither in sol nor in gel form; After-treatment thereof by acidic treatment of silicates
    • C01B33/193—Preparation of finely divided silica neither in sol nor in gel form; After-treatment thereof by acidic treatment of silicates of aqueous solutions of silicates

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  • the present invention relates to a novel method for preparing precipitated silica, in particular using a fast blender.
  • precipitated silica is known as a catalyst support, as an absorbent for active materials (in particular supports for liquids, for example used in foods, such as vitamins (in particular vitamin E), choline chloride), as a viscosifying, texturizing or anti-caking agent, as an element for battery separators, as a toothpaste and paper additive, etc.
  • Precipitated silica can also be employed as a reinforcing filler in silicon matrices (for example for coating electrical cables) or in compositions based on polymer(s), in particular elastomer(s).
  • Methods for obtaining precipitated silica conventionally involve adding the reactants to a stirred reactor (vessel). These methods may have drawbacks, in particular when the precipitation operation comprises the simultaneous addition of silicate and acidifying agent in acidic medium.
  • This simultaneous addition step is often difficult to control, thereby substantially reducing the reliability of the method, or even making it really unreliable and therefore not robust.
  • the precipitation of silica in these methods comprises rather fast reaction steps, whose control may depend in particular on the mixing quality of the reactants and hence the mixing performance of the reactor. Due to the speed of the reactions, the stirred reactor may display wide heterogeneities in the concentration of the reactants and of the products.
  • the invention proposes a novel method for preparing precipitated silica which constitutes an alternative to the known methods for preparing precipitated silica and which advantageously serves to remedy the abovementioned drawbacks.
  • the present invention proposes a method for preparing precipitated silica, of the type comprising reacting a silicate with an acidifying agent for obtaining a suspension of precipitated silica, and separating and drying this suspension, characterized in that the precipitation comprises contacting (mixing) a silicate with an acidifying agent in acidic medium (the reaction medium has an acidic pH), in a fast blender.
  • the invention also proposes a method for preparing precipitated silica, of the type comprising reacting a silicate with an acidifying agent for obtaining a suspension of precipitated silica, and separating and drying this suspension, characterized in that the precipitation comprises contacting (mixing) a silicate with an acidifying agent in acidic medium (the reaction medium has an acidic pH), in a turbulent flow zone.
  • said contacting (mixing) of a silicate with an acidifying agent is carried out at a pH of between 2 and 5.5, preferably between 2 and 5.
  • This introduction of the silicate into the fast blender (or into the turbulent flow zone) is generally carried out continuously.
  • the reaction medium resulting from the contacting of the silicate with the acidifying agent is fed to a reactor, preferably subject to stirring, said reactor generally operating in semi-continuous mode.
  • a reactor preferably subject to stirring
  • at least one aggregation/growth of the silica particles formed generally takes place.
  • a reactor (vessel) preferably stirred, is placed in series after the fast blender.
  • the fast blender may in particular be selected from symmetrical T or Y blenders (or tubes), asymmetrical T or Y blenders (or tubes), tangential jet blenders, Hartridge-Roughton blenders, vortex blenders, rotor-stator blenders.
  • Symmetrical T or Y blenders generally consist of two opposing tubes (T tubes) or tubes making an angle smaller than 0 to 180° (Y tubes), having the same diameter, discharging into a central tube having an identical or higher diameter than that of the preceding two tubes. They are said to be symmetrical because the two reactant injection tubes have the same diameter and the same angle to the central tube, the device being characterized by an axis of symmetry.
  • the central tube has a diameter about two times higher than the diameter of the opposing tubes; similarly, the speed of the fluid in the central tube is preferably equal to half of that in the opposing tubes.
  • one of the fluids (generally the fluid with the lower flow rate) is injected into the central tube via a side tube having a smaller diameter.
  • the latter generally makes a 90° angle with the central tube (T tube); this angle may be different from 90° (Y tube), producing cocurrent systems (for example 45° angle) or countercurrent systems (for example 135° angle) with regard to the other stream.
  • the method according to the present invention makes use of a tangential jet blender, a Hartridge-Roughton blender or a vortex blender (or precipitator), which are derived from symmetrical T devices.
  • the contacting of a silicate with an acidifying agent is carried in a tangential jet, Hartridge-Roughton or vortex blender, comprising a chamber having at least two tangential inlets via which the silicate and acidifying agent enter separately (but simultaneously), and an axial outlet via which the reaction medium exits, preferably to a ieactor (vessel) placed in series after said blender.
  • the two tangential inlets are preferably located symmetrically, and in opposition, about the centerline of said chamber.
  • the chamber of the tangential jet, Hartridge-Roughton or vortex blender used generally has a circular cross section and preferably a cylindrical shape.
  • Each tangential inlet tube may have an inside diameter d of 0.5 to 80 mm.
  • This inside diameter d may be between 0.5 and 10 mm, in particular between 1 and 9 mm, for example between 2 and 7 mm. However, particularly at industrial scale, it is preferably between 10 and 80 mm, in particular between 20 and 60 mm, for example between 30 and 50 mm.
  • the inside diameter of the chamber of the tangential jet, Hartridge-Roughton or vortex blender employed may be between 3 d and 6 d, in particular between 3 d and 5 d, for example equal to 4 d; the inside diameter of the axial outlet tube may be between 1 d and 3 d, in particular between 1.5 d and 2.5 d, for example equal to 2 d.
  • the flow rates of silicate and acidifying agent are determined for example so that at the point of confluence, the two reactant streams enter into contact with one another in a sufficiently turbulent flow zone.
  • the method according to the present invention generally does not comprise any (formation of) initial bottoms.
  • the precipitation is carried out as follows:
  • silicate and acidifying agent are added simultaneously to said fast blender, preferably in continuous mode, the pH of the reaction medium (pH 1 ) being between 2 and 5.5, in particular between 2 and 5,
  • step (ii) the reaction medium issuing from step (i) is introduced into at least one stirred reactor, in particular in semi-continuous mode, the pH of the reaction medium (pH 2 ) in the reactor being regulated between 2 and 5.5, in particular between 2 and 5, preferably with pH 2 ⁇ pH 1 ,
  • step (iii) silicate is added to the reaction medium issuing from step (ii), in the stirred reactor, until the pH value of the reaction mixture obtained is between 7 and 10, in particular between 7.5 and 9.5,
  • silicate and acidifying agent are added simultaneously to the reaction medium issuing from step (iii), in the stirred reactor, so that the pH of the reaction medium is maintained between 7 and 10, in particular between 7.5 and 9.5.
  • the silicate addition is interrupted while continuing to add acidifying agent to the reaction medium of the stirred reactor until the pH value of the reaction medium obtained in the stirred reactor is lower than 6, preferably between 3 and 5.5, for example between 3 and 5.
  • the acidifying agent and silicate employed in step (i) are preferably diluted, and for example prepared by dilution and heating in line of the generally more concentrated acidifying agent and silicate used in the other steps of the inventive method.
  • acidifying agent use is generally made of a strong inorganic acid such as sulfuric acid, nitric acid or hydrochloric acid, or an organic acid such as acetic acid, formic acid or carbonic acid.
  • the normality of the acidifying agent may be between 0.1 and 36 N, for example between 0.2 and 1.5 N.
  • the acidifying agent is sulfuric acid
  • its concentration, in step (i) may be between 5 and 50 g/l, for example between 10 and 35 g/l
  • its concentration, in the other steps may be between 40 and 180 g/l, for example between 60 and 130 g/l.
  • silica can also be used as silicate, such as metasilicates, disilicates and advantageously, an alkali metal silicate, in particular sodium or potassium silicate.
  • the silicate may have a concentration (expressed as SiO 2 ) of between 5 and 100 g/l, for example between 20 and 90 g/l, in particular between 25 and 80 g/l; its concentration (expressed as SiO 2 ), in the other steps, may be between 40 and 330 g/l, for example between 60 and 300 g/l, in particular between 60 and 260 g/l.
  • sulfuric acid is employed as acidifying agent
  • sodium silicate as the silicate
  • sodium silicate In the case in which sodium silicate is used, it generally has a SiO 2 /Na 2 O weight ratio of between 2.5 and 4, in particular between 3.2 and 3.8, for example between 3.4 and 3.7.
  • the reaction of the silicate with the acidifying agent takes place very specifically according to the following steps.
  • step (i)) consists of a simultaneous addition of silicate and acidifying agent in a fast blender, preferably in continuous mode, at a pH (pH 1 ) of between 2 and 5.5, in particular between 2 and 5.
  • a tangential jet blender is used in this embodiment of the present invention, and even more preferably, a Hartridge-Roughton blender or a vortex blender (precipitator).
  • the contacting of the silicate with an acidifying agent is carried in a tangential jet, Hartridge-Roughton or vortex fast blender, comprising a chamber having at least two tangential inlets via which the silicate and acidifying agent enter separately (but simultaneously), and an axial outlet via which the reaction medium exits, preferably to a reactor (vessel) placed in series after said blender.
  • the two tangential inlets are preferably located symmetrically, and in opposition, about the centerline of said chamber.
  • the chamber of the tangential jet, Hartridge-Roughton or vortex blender used generally has a circular cross section and preferably a cylindrical shape.
  • Each tangential inlet tube may have an inside diameter d of 0.5 to 80 mm.
  • This inside diameter d may be between 0.5 and 10 mm, in particular between 1 and 9 mm, for example between 2 and 7 mm. However, particularly at industrial scale, it is preferably between 10 and 80 mm, in particular between 20 and 60 mm, for example between 30 and 50 mm.
  • the inside diameter of the chamber of the tangential jet, Hartridge-Roughton or vortex blender employed may be between 3 d and 6 d, in particular between 3 d and 5 d, for example equal to 4 d; the inside diameter of the axial outlet tube may be between 1 d and 3 d, in particular between 1.5 d and 2.5 d, for example equal to 2 d.
  • An electrolyte may optionally be used in step (i). However, preferably, no electrolyte is added during the preparation method, in particular in step (i).
  • electrolyte is understood here in its normal acceptation, that is meaning any ionic or molecular substance which, when in solution, decomposes or dissociates to form ions or charged particles.
  • electrolyte of a salt of the group of alkali metal or alkaline earth metal salts in particular the metal salt of the starting silicate and of the acidifying agent, for example sodium chloride in the case of the reaction of a sodium silicate with hydrochloric acid or, preferably, sodium silicate in the case of the reaction of a sodium silicate with sulfuric acid.
  • ultrasonic treatment in particular during the contacting of the reactants in the fast blender, is unnecessary and is preferably not employed.
  • a reaction medium resulting from the contacting of the silicate and with the acidifying agent is fed to a reactor (vessel), subject to stirring, this reactor (vessel) generally operating in semi-continuous mode.
  • a stirred reactor (vessel) is placed in series after the fast blender.
  • the pH of the reaction medium (pH 2 ) in the reactor (vessel) subjected to stirring is regulated between 2 and 5.5, in particular between 2 and 5, in particular between 2.5 and 5, for example between 3 and 4.5, or even between 4 and 4.5; this pH (pH 2 ) may be equal to 4.4 ⁇ 0.1.
  • pH 2 ⁇ pH 1 it is possible to have pH 2 ⁇ pH 1 , but preferably, pH 2 ⁇ pH 1 .
  • the inventive method generally does not comprise any (formation of) initial bottoms; but this is not always the case: thus, even if this is not a highly preferred alternative, the stirred reactor may optionally comprise, prior to the addition of the reaction medium issuing from step (i), aqueous bottoms having a pH of between 2 and 5.5, in particular between 2 and 5.
  • step (ii) in order to regulate the pH of the reaction medium (pH 2 ) in the stirred reactor to the desired value, between 2 and 5.5, in particular between 2 and 5, especially between 2.5 and 5, acidifying agent or rather, preferably, silicate or a basifying agent (such as sodium hydroxide), can be added simultaneously to the reaction medium issuing from the fast blender.
  • acidifying agent or rather, preferably, silicate or a basifying agent such as sodium hydroxide
  • the pH measurement both in the and/or at the outlet of the fast blender and in the stirred reactor, must be particularly reliable and therefore make use of appropriate pH probes/electrodes.
  • For measuring the pH at the outlet of the fast blender use can be made for example of a Mettler Ingold 3200 probe or electrode, and for measuring the pH in the stirred reactor, a Mettler Ingold 4800 probe or electrode.
  • silicate is added to the reaction medium in the reactor, with stirring, in order to obtain a pH value of the reaction medium between 7 and 10, preferably between 7.5 and 9.5.
  • a maturation of the reaction medium may optionally be carried out just after this step (iii) and hence just after the interruption of the silicate addition, particularly at the pH obtained on completion of step (iii), and in general with stirring; this maturation may, for example, last 2 to 45 minutes, in particular 5 to 25 minutes, and preferably not comprise any addition of acidifying agent nor silicate addition.
  • step (iii), and the optional maturation a new simultaneous addition of acidifying agent and silicate is carried out, so that (in particular at such flow rates) the pH value of the reaction medium is maintained between 7 and 10, preferably between 7.5 and 9.5.
  • This second simulteneous addition (step(iv)) is advantageously carried out in such a way that the pH of the reaction medium is constantly equal (to within ⁇ 0.2) to the pH reached on completion of the previous step.
  • step (v) the silicate addition is interrupted while continuing to add acidifying agent to the reaction medium in order to obtain a pH value of the reaction medium lower than 6, preferably between 3 and 5.5, in particular between 3 and 5, for example between 3.5 and 5.
  • a maturation of the reaction medium may be carried out after this step (v) and hence just after interrupting the addition of acidifying agent, particularly at the pH obtained on completion of step (v), and in general with stirring; this maturation may for example last 2 to 45 minutes, in particular 5 to 20 minutes and preferably not comprise any addition of acidifying agent nor any silicate addition.
  • reaction chamber in which all the steps (ii) to (v) are carried out is equipped with a stirring unit and, generally, appropriate heating equipment.
  • the entire precipitation is preferably carried out between 70 and 95° C., in particular between 75 and 95° C.
  • the entire reaction of silicate with acidifying agent is carried out at a constant temperature, usually between 70 and 95° C., in particular between 75 and 95° C.
  • the temperature at the end of the reaction is higher than the temperature at the start of the reaction: thus, the temperature at the start of the reaction is maintained (for example during steps (i) and (ii), the temperature in step (ii) generally being equal to or higher than that of step (i)) preferably between 70 and 86° C., for example between 70 and 85° C. or between 76 and 86° C., and the temperature is then increased (for example during step (iii)), preferably to a value of between 85 (or 86) and 95° C., at which it is maintained (for example during steps (iv) and (v)) until the end of the reaction.
  • the contacting of the starting reactants is very uniform and very fast; all the reactants preferably react in the same way.
  • the residence time in the turbulent flow zone or through the fast blender is advantageously shorter than 1 second, in particular shorter than 0.5 second, for example no longer than 0.3 second, or even no longer than 0.1 second; it is generally longer than 0.001 second, particularly longer than 0.01 second, for example longer than 0.03 second. More particularly during an industrial implementation, this residence time in the fast blender may be between 0.04 and 0.3 second, for example between 0.05 and 0.25 second.
  • at least 95% preferably at least 99%, by volume of the mixture is uniform.
  • the stirring rate in the reactor (vessel), particularly in the preferred embodiment of the invention, may for example be between 60 and 700 rpm, in particular between 75 and 300 rpm.
  • the inventive method allows control of the step of simultaneous addition of the starting reactants and thereby serves to feed the stirred reactor with a uniform reaction medium, making it possible to eliminate the difficulties of a method in which the precipitation operation is entirely carried out in a stirred reactor.
  • One of the advantages of the inventive methods, in particular according to the preferred embodiment of the invention is that, in combination with other specific steps, with the use of a fast blender, in particular a tangential jet, Hartridge-Roughton or vortex blender, placed in series before the reactor, it serves to eliminate in particular the heterogeneities found in a method in which the precipitation operation is entirely carried out in a stirred reactor; a decrease in the time of introduction of the starting reactants is observed, as well as better process control and silica properties.
  • the method according to the preferred embodiment of the invention is a reliable, robust method, allowing control of the quality of the silica prepared, and advantageously has very satisfactory productivity.
  • the separation carried out in the preparation method according to the invention usually comprises a filtration, followed by a washing if necessary.
  • the filtration takes place by any appropriate method, for example using a filter press, a belt filter, a vacuum filter.
  • the silica suspension thus recovered (filter cake) is then dried.
  • This drying can be carried out by any means known per se.
  • the drying is preferably carried out by spray drying.
  • spray drying use can be made of any appropriate spray dryer, in particular a turbine, nozzle, liquid pressure or dual fluid spray dryer.
  • a turbine spray dryer or nozzle spray dyer is used, and when the filtration is carried out using a vacuum filter, a turbine spray dryer is used.
  • the filter cake is not always in a condition allowing spray drying, particularly due to its high viscosity.
  • this cake is subjected to a disintegration operation.
  • This operation can be carried out mechanically, by passing the cake through a colloidal grinder or ball mill.
  • the disintegration is generally carried out in the presence of an aluminum compound, in particular sodium aluminate and, optionally, in the presence of an acidifying agent as described above (in the latter case, the aluminum compound and the acidifying agent are generally added simultaneously).
  • the disintegration operation serves in particular to lower the viscosity of the suspension to be dried later.
  • the silica that may then be obtained is usually in the form of substantially spherical beads.
  • the product recovered may be subjected to a grinding step.
  • the silica that is then likely to be obtained is generally in the form of a powder.
  • the silica that may be obtained may be in the form of a powder.
  • the dried product in particular dried by a turbine spray dryer or ground as indicated above may optionally be subjected to an agglomeration step, which consists for example of a direct compression, a wet granulation (that is with the use of a binder such as water, silica suspension, etc.), an extrusion or, preferably, a dry compaction.
  • an agglomeration step which consists for example of a direct compression, a wet granulation (that is with the use of a binder such as water, silica suspension, etc.), an extrusion or, preferably, a dry compaction.
  • the silica that may then be obtained by this agglomeration step is generally in the form of granules.
  • the silica powders like the beads, obtained by the method according to the invention thus offer the advantage, among others, of being converted simply, effectively and economically, to granules, particularly by conventional shaping operations, such as for example a granulation or compaction, without the latter causing any damage liable to mask, or even destroy, the good intrinsic properties attached to these powders or these beads, as may be the case in the prior art when conventional powders are employed.
  • the preparation method according to the invention serves in particular to obtain precipitated silica which, on the one hand, is highly structured and not friable and, on the other hand, preferably has a particular grain size distribution and/or pore distribution.
  • the BET specific surface area is determined by the BRUNAUER-EMMETT-TELLER method described in “The Journal of the American Chemical Society”, Vol. 60, page 309, February 1938 and corresponding to international standard ISO 5794/1 (Annex D).
  • the CTAB specific surface area is the outer surface area determined to standard NF T 45007 (November 1987) (5.12).
  • the DOP oil intake is determined according to standard NF T 30-022 (March 1953) using dioctylphthalate.
  • the pH is measured according to standard ISO 787/9 (pH of a 5% suspension in water).
  • the XDC grain-size analysis method by centrifugal sedimentation used to measure, on the one hand, the widths of the object size distribution of the silica and, on the other hand, the XDC mode illustrating its object size, is described below:
  • the object size distribution width Ld measured by XDC grain-size analysis, after the ultrasonic disaggregation (in water) corresponds to the ratio (d84-d16)/d50 in which dn is the size for which there are n % of particles (by weight) smaller than this size (hence the distribution width Ld is calculated on the cumulative grain size distribution curve, considered as a whole).
  • the size distribution width L′d of objects smaller than 500 nm, measured by XDC grain-size analysis, after ultrasonic disaggregation (in water), corresponds to the ratio (d84-d16)/d50 in which dn is the size for which there are n % of particles (by weight), with regard to the particles smaller than 500 nm, which are smaller than this size (hence the distribution width L′d is calculated on the cumulative grain-size distribution curve, cut above 500 nm).
  • d w an average size (by weight) of the particles (that is of the secondary particles or aggregates), denoted d w , after dispersion, by ultrasonic disaggregation of the silica in water.
  • the method differs from the one previously described in the fact that the suspension formed (silica+permuted water) is disaggregated, on the one hand, for 8 minutes, and on the other hand, using a Vibracell 1.9 cm ultrasonic probe (sold by Bioblock) of 1500 watts (used at 60% of maximum capacity).
  • d w The geometric mean by weight of the particle size (Xg in the software), denoted d w , is calculated by the software from the following equation:
  • m i is the mass of all the objects in the size class d i .
  • each sample is prepared as follows: each sample is previously dried for 2 hours in an oven at 200° C., and then placed in a test, container within 5 minutes after leaving the oven and vacuum-degasified, for example using a rotary distributor pump; the pore diameters (Micrometrics AutoPore III 9420 porosimeter) are calculated by the Washburn equation with a theta contact angle of 140° C. and a gamma surface tension of 484 Dynes/cm (or N/m).
  • V (ds-d50) denotes the pore volume consisting of the pores with diameters between d5′ and d50
  • V (d5-d100) is the pore volume consisting of the pores with diameters between d5 and d100, do here being the pore diameter for which n % of the total area of all of the pores is provided by the pores larger than this diameter (the total area of the pores (S 0 ) can be determined from the mercury intrusion curve).
  • the aptitude to dispersion (and to disaggregation) of the silica obtained by the inventive method can be quantified by means of specific disaggregation tests.
  • the cohesion of the aggregates is assessed by a grain size measurement (by laser diffraction) carried out on a suspension of silica previously disaggregated by ultrasonication; the aptitude of the silica to disaggregation is thus measured (fracture of objects between 0.1 and a few tens of microns).
  • Ultrasonic disaggregation is carried out using a Vibracell Bioblock 600 W) sonicator, equipped with a 19 mm diameter probe.
  • the grain size measurement is taken by laser diffraction on a Sympatec grain-size analyzer.
  • the value of the median diameter ⁇ 50S (or Sympatec median diameter) obtained is lower if the silica has a high aptitude to disaggregation. It is also possible to determine the ratio (10 ⁇ volume of suspension introduced (in ml))/optical density of the suspension detected by the grain-size analyzer (this optical density is about 20). This ratio indicates the proportion of particles smaller than 0.1 ⁇ m which are not detected by the grain-size analyzer. This ratio is called the (Sympatec) ultrasonic disaggregation factor (F DS ).
  • the cohesion of the aggregates is assessed by a grain size measurement (by laser diffraction) carried out on a suspension of silica previously disaggregated by ultrasonication; the aptitude of the silica to disaggregation is thus measured (fracture of objects between 0.1 and a few tens of microns).
  • Ultrasonic disaggregation is carried out using a Vibracell Bioblock 600 W) sonicator, used at 80% of maximum capacity, equipped with a 19 mm diameter probe.
  • the grain size measurement is taken by laser diffraction on a Malvern (Mastersizer 2000) grain-size analyzer.
  • silica 1 gram is weighed in a pillbox (height: 6 cm and diameter: 4 cm), and made up to 50 g by adding permuted water: this produces an aqueous suspension containing 2% silica which is homogenized for 2 minutes by magnetic stirring. The disaggregation is carried out for 420 seconds. The grain size measurement is then taken after having introduced a known volume of homogenized suspension into the cell of the grain-size analyzer.
  • the value of the median diameter ⁇ 50M (or Malvern median diameter) obtained is lower if the silica has a high aptitude to disaggregation. It is also possible to determine the ratio (10 ⁇ value of blue laser darkening)/value of red laser darkening. This ratio indicates the proportion of particles smaller than 0.1 ⁇ m. This ratio is called the (Malvern) ultrasonic disaggregation factor (F DM ).
  • the Sears number is determined by the method described by G. W. Sears in an article in “Analytical Chemistry, Vol. 28, No. 12, December 1956” entitled “Determination of specific surface area of colloidal silica by titration with sodium hydroxide”.
  • the Sears number is the volume of 0.1 M sodium hydroxide solution required to raise the pH of a 10 g/l silica suspension in 200 g/l sodium chloride medium from 4 to 9.
  • a 200 g/l sodium chloride solution is prepared, acidified to pH 3 with a 1 M hydrochloric acid solution.
  • the weighings are performed using a Mettler precision balance.
  • 150 ml of this sodium chloride solution is added delicately to a 250 ml beaker into which a mass M (in g) of the sample to be analyzed has been introduced, corresponding to 1.5 grams of dry silica.
  • Ultrasound is applied to the dispersion obtained for 8 minutes (Branson 1500 W ultrasonic probe, amplitude 60%, diameter 13 mm), the beaker being placed in an ice-filled chiller.
  • the solution obtained is then homogenized by magnetic stirring, using a magnetic rod measuring 25 mm ⁇ 5 mm.
  • the titrating pH meter has been programmed as follows: 1) Called the “Get pH” program, 2) Enter the following parameters: pause (pause before start of titration): 3 s, reactant flow rate: 2 ml/min, anticipation (adaptation of the titration rate to the slope of the pH curve): 30, stop pH: 9.40, critical EP (detection sensitivity at equivalence point): 3, report (in parameters of the titration ratio): 2, 3, 5 (that is creation of a detailed report, list of measurement points, titration curve)).
  • the exact volumes V 1 and V 2 of the sodium hydroxide solution added to obtain a pH of 4 and a pH of 9 respectively are determined by interpolation.
  • the Sears number for 1.5 grams of dry silica is equal to ((V 2 ⁇ V 1 ) ⁇ 150)/(ES ⁇ M), where:
  • the inventive method serves to prepare a precipitated silica having:
  • This silica has for example:
  • This silica may have a ratio of V (d5-d50) /V (d5-d100) of at least 0.73, in particular of at least 0.74. This ratio may be at least 0.78, in particular at least 0.80, or even at least 0.84.
  • the inventive method serves also to prepare a precipitated silica having:
  • This silica may have a pore distribution width 1 dp higher than 1.05, for example 1.25 or even 1.40.
  • This silica preferably has an object size distribution width Ld ((d84 ⁇ d16)/d50) measured by XDC grain-size analysis after ultrasonic disaggregation of at least 0.91, in particular at least 0.94, for example at least 1.0.
  • the inventive method in particular according to the preferred embodiment of the invention also serves to prepare a precipitated silica having:
  • This silica may have a ratio of V (d5-d50) /V (d5-d100) of at least 0.73, in particular of at least 0.74. This ratio may be at least 0.78, in particular at least 0.80, or even at least 0.84.
  • the inventive method serves also to prepare a precipitated silica having:
  • This silica may have a ratio of V (d5-d50) /V (d5-d100) of at least 0.78, in particular at least 0.80, or even at least 0.84.
  • the pore volume provided by the largest pores normally accounts for the majority of the structure.
  • They may have both an object size distribution width Ld of at least 1.04 and a size distribution width L′d of objects (smaller than 500 nm) of at least 0.95.
  • the object size distribution width Ld of these silicas may in certain cases be at least 1.10, in particular at least 1.20; it may be at least 1.30, for example at least 1.50, or even at least 1.60.
  • the size distribution width L′d of objects may for example be at least 1.0, in particular be at least 1.10, in particular at least 1.20.
  • these silicas have a particular surface chemistry, such as to have a ratio (Sears number ⁇ 1000)/(BET specific surface area (S BET )) lower than 60, preferably lower than 55, for example lower than 50.
  • XDC mode (nm) ⁇ (5320/S CTAB (m 2 /g))+8, or even the condition: XDC mode (nm) ⁇ (5320/S CTAB (m 2 /g))+10.
  • V 80 may for example have a poor volume (V 80 ) consisting of the pores having diameters between 3.7 and 80 nm of at least 1.35 cm 3 /g, in particular at least 1.40 cm 3 /g, or even at least 1.50 cm 3 /g.
  • ⁇ 50S Their median diameter ( ⁇ 50S ), after ultrasound disaggregation, is generally lower than 8.5 ⁇ m; it may be lower than 6.0 ⁇ m, for example lower than 5.5 ⁇ m.
  • ⁇ 50M median diameter after ultrasonic disaggregation, is generally lower than 8.5 ⁇ m; it may be lower than 6.0 ⁇ m, for example lower than 5.5 ⁇ m.
  • These silicas may have an ultrasonic disaggregation factor (F DS ) higher than 3 ml, in particular higher than 3.5 ml, in particular higher than 4.5 ml.
  • F DS ultrasonic disaggregation factor
  • F DM ultrasonic disaggregation factor
  • d w average particle size (by mass) measured by XDC grain-size analysis after ultrasonic disaggregation, d w , of between 20 and 300 nm in particular between 30 and 300 nm in particular between 40 and 160 nm.
  • They may have a particle size distribution such that dw ⁇ (16500/S CTAB ) ⁇ 30.
  • the silicas prepared by the invention generally have:
  • Their CTAB specific surface area may be between 90 and 230 m 2 /g.
  • their BET specific surface area may be between 110 and 270 m 2 /g, in particular between 115 and 250 m 2 /g, for example between 135 and 235 m 2 /g.
  • the silicas prepared by the invention generally have:
  • Their CTAB specific surface area may be between 115 and 260 m 2 /g, in particular between 145 and 260 m 2 /g.
  • their BET specific surface area may be between 120 and 280 m 2 /g, in particular between 150 and 280 m 2 /g.
  • the silicas prepared by the present invention may have a certain microporosity; thus, these silicas are normally such that
  • This microporosity is generally not too high; these silicas are generally such that (S BET -S CTAB ) ⁇ 50 m 2 /g, preferably ⁇ 40 m 2 /g.
  • the pH of the silicas obtained by the invention is normally between 6.3 and 7.8, in particular between 6.6 and 7.5.
  • DOP oil intake which usually varies between 220 and 330 ml/100 g, for example between 240 and 300 ml/100 g.
  • They may be in the form of substantially spherical beads having an average size of at least 80 ⁇ m.
  • This average bead size may be at least 100 ⁇ m, for example at least 150 ⁇ m; it is generally at least no more than 300 ⁇ m and is preferably between 100 and 270 ⁇ m. This average size is determined according to standard NF X 11507 (December 1970) by dry screening and determination of the diameter corresponding to an oversize of 50%.
  • They may also be in the form of a powder having an average size of at least 15 ⁇ m; this is for example between 15 and 60 ⁇ m, (in particular between 20 and 45 ⁇ m) or between 30 and 150 ⁇ m (in particular between 45 and 120 ⁇ m).
  • They may also be in the form of granules having a size of at least 1 mm, in particular between 1 and 10 mm, according to their major axis (length).
  • the silicas prepared by the inventive methods may have an advantageous application for reinforcing polymers, natural or synthetic.
  • the polymer(s) compositions in which they can be used, as reinforcing filler, are generally based on one or more polymers or copolymers, in particular one or more elastomers, in particular thermoplastic elastomers, preferably having at least a glass transition temperature of between ⁇ 150 and +300° C., for example between ⁇ 150 and +20° C.
  • dienic polymers in particular dienic elastomers, for example polybutadienes (BR), polyisoprenes (IR), styrene-butadiene copolymers (SBR, in particular ESBR (emulsion) or SSBR (solution)). Mention can also be made of natural rubber (NR).
  • BR polybutadienes
  • IR polyisoprenes
  • SBR styrene-butadiene copolymers
  • ESBR styrene-butadiene copolymers
  • ESBR styrene-butadiene copolymers
  • ESBR styrene-butadiene copolymers
  • ESBR styrene-butadiene copolymers
  • NR natural rubber
  • the polymer(s) compositions can be vulcanized with sulfur or crosslinked in particular with peroxides.
  • the polymer(s) compositions further comprise at least one coupling agent (silica/polymer).
  • coupling agent use can be made in particular, as nonlimiting examples, of a polysulfide silane (called “symmetrical” or “asymmetrical”, such as monoethoxydimethylsilylpropyl tetrasulfide.
  • the proportion by weight of silica in the polymer(s) composition normally accounts for 20 to 80%, for example 30 to 70%, of the quantity of polymer(s).
  • the silica prepared by the inventive method may constitute all the reinforcing filler of the polymer(s) composition.
  • another reinforcing filler can be combined with the silica, such as in particular a commercial highly dispersible silica such as for example Z1165MP silica, Z1115MP silica, another reinforcing inorganic filler such as for example alumina, or even a reinforcing organic filler, such as carbon black.
  • a commercial highly dispersible silica such as for example Z1165MP silica, Z1115MP silica
  • another reinforcing inorganic filler such as for example alumina
  • a reinforcing organic filler such as carbon black.
  • the silicas prepared by the inventive method can also be employed as a catalyst support, as absorbent of active materials (in particular liquid support, for example used in foods, such as vitamins (vitamin E), choline chloride), as viscosifying, texturizing or anti-caking agents, as elements for battery separators, as toothpaste and paper additives.
  • active materials in particular liquid support, for example used in foods, such as vitamins (vitamin E), choline chloride
  • viscosifying, texturizing or anti-caking agents as elements for battery separators, as toothpaste and paper additives.
  • the silica precipitation reaction is carried out by sequencing a Hartridge-Roughton type stainless steel fast blender, with an inlet diameter d of 5 mm (FIGURE), and a stirred (160 rpm) stainless steel vessel having a volume of 170 L, in the following steps.
  • a sodium silicate solution (SiO 2 /Na 2 O weight ratio 3.45), having a concentration of 50 g/L and a temperature of 77° C., at a flow rate of 377 L/h, is added to the fast blender for 8 minutes and 30 seconds, simultaneously with sulfuric acid, having a concentration of 21 g/L and a temperature of 77° C., at a flow rate regulated in order to maintain the pH of the reaction medium at a value of 4.0.
  • This reaction medium is accommodated in the stirred vessel, into which a sodium silicate solution is introduced simultaneously at a flow rate regulated in order to maintain the pH of the reaction medium at a value of 4.2.
  • the temperature is increased to 84° C.
  • the feeds of the fast blender are interrupted and a sodium silicate solution is introduced into the stirred vessel until pH value of 8.0 is obtained.
  • the temperature is increased to 92° C. and maintained at this level until the end of the reaction.
  • a new simultaneous addition of sodium silicate and sulfuric acid is carried out for 40 minutes in the stirred vessel, with a sodium silicate flow rate of 35 L/h, in a concentration of 235 g/L, and a sulfuric acid flow rate, having a concentration of 80 g/L, regulated in order to maintain the pH of the reaction medium at a value of 8.0.
  • reaction medium is adjusted to a pH of 3.9 in 5 minutes by sulfuric acid having a concentration of 80 g/L.
  • the slurry obtained is filtered and washed on a filter press (dry extract of the cake 20%). After dilution, the cake obtained is mechanically disintegrated, adding sodium aluminate (Na 2 O/Al 2 O 3 weight ratio 0.8), in an Al/SiO 2 ratio of 0.3% and sulfuric acid until a pH of 6.5 is reached.
  • the resulting. slurry (having a dry extract of 11%) is spray dried using a turbine spray dryer.
  • the silica precipitation reaction is carried out by sequencing a Hartridge-Roughton type stainless steel fast blender, with an inlet diameter d of 5 mm (FIGURE), and a stirred (160 rpm) stainless steel vessel having a volume of 170 L, in the following steps.
  • a sodium silicate solution (SiO 2 /Na 2 O weight ratio 3.45), having a concentration of 50 g/L and a temperature of 79° C., at a flow rate of 458 L/h, is added to the fast blender for 7 minutes, simultaneously with sulfuric acid, having a concentration of 21 g/L and a temperature of 79° C., at a flow rate regulated in order to maintain the pH of the reaction medium at a value of 4.6.
  • This reaction medium is accommodated in the stirred vessel, into which a sodium silicate solution is introduced simultaneously at a flow rate regulated in order to maintain the pH of the reaction medium at a value of 4.3.
  • the temperature is increased to 81° C.
  • the feeds of the fast blender are interrupted and a sodium silicate solution is introduced into the stirred vessel until pH value of 8.0 is obtained.
  • the temperature is increased to 92° C. and maintained at this level until the end of the reaction.
  • a new simultaneous addition of sodium silicate and sulfuric acid is carried out for 40 minutes in the stirred vessel, with a sodium silicate flow rate of 34 L/h, in a concentration of 235 g/L, and a sulfuric acid flow rate, having a concentration of 80 g/L, regulated in order to maintain the pH of the reaction medium at a value of 8.0.
  • reaction medium is adjusted to a pH of 3.9 in 5 minutes by sulfuric acid having a concentration of 80 g/L.
  • the slurry obtained is filtered and washed on a filter press (dry extract of the cake 20%): After dilution, the cake obtained is mechanically disintegrated, adding sodium aluminate (Na 2 O/Al 2 O 3 weight ratio 0.8), in an Al/SiO 2 ratio of 0.3% and sulfuric acid until a pH of 6.5 is reached.
  • the resulting slurry (having a dry extract of 11%) is spray dried using a turbine spray dryer.
  • the silica precipitation reaction is carried out by sequencing a Hartridge-Roughton type stainless steel fast blender, with an, inlet diameter d of 5 mm (FIGURE), and a stirred (160 rpm) stainless steel vessel having a volume of 170 L, in the following steps.
  • a sodium silicate solution (SiO 2 /Na 2 O weight ratio 3.45), having a concentration of 50 g/L and a temperature of 82° C., at a flow rate of 382 L/h, is added to the fast blender for 8 minutes and 30 seconds, simultaneously with sulfuric acid, having a concentration of 21 g/L and a temperature of 82° C., at a flow rate regulated in order to maintain the pH of the reaction medium at a value of 3.1.
  • This reaction medium is accommodated in the stirred vessel, into which a sodium silicate solution is introduced simultaneously at a flow rate regulated in order to maintain the pH of the reaction medium at a value of 4.3.
  • the temperature is increased to 82° C.
  • the feeds of the fast blender are interrupted and a sodium silicate solution is introduced into the stirred vessel until pH value of 8.0 is obtained.
  • the temperature is increased to 92° C. and maintained at this level until the end of the reaction.
  • a new simultaneous addition of sodium silicate and sulfuric acid is carried out for 40 minutes in the stirred vessel, with a sodium silicate flow rate of 34 L/h, in a concentration of 235 g/L, and a sulfuric acid flow rate, having a concentration of 80 g/L, regulated in order to maintain the pH of the reaction medium at a value of 8.0.
  • reaction medium is adjusted to a pH of 3.9 in 5 minutes by sulfuric acid having a concentration of 80 g/L.
  • the slurry obtained is filtered and washed on a filter press (dry extract of the cake 21%). After dilution, the cake obtained is mechanically disintegrated, adding sodium aluminate (Na 2 O/Al 2 O 3 weight ratio 0.8), in an Al/SiO 2 ratio of 0.3% and sulfuric acid until a pH of 6.5 is reached. The resulting slurry (having a dry extract of 11%) is spray dried using a turbine spray dryer.
  • sodium aluminate Na 2 O/Al 2 O 3 weight ratio 0.8
  • the silica precipitation reaction is carried out by sequencing a Hartridge-Roughton type stainless steel fast blender, with an inlet diameter d of 5 mm (FIGURE), and a stirred (160 rpm) stainless steel vessel having a volume of 170 L, in the following steps.
  • a sodium silicate solution (SiO 2 /Na 2 O weight ratio 3.45), having a concentration of 50 g/L and a temperature of 79° C., at a flow rate of 321 L/h is added to the fast blender for 10 minutes, simultaneously with sulfuric acid, having a concentration of 21 g/L and a temperature of 79° C., at a flow rate regulated in order to maintain the pH of the reaction medium at a value of 4.6.
  • This reaction medium is accommodated in the stirred vessel, into which a sodium silicate solution is introduced simultaneously at a flow rate regulated in order to maintain the pH of the reaction medium at a value of 4.4.
  • the temperature is increased to 81° C.
  • the feeds of the fast blender are interrupted and a sodium silicate solution is introduced into the stirred vessel until pH value of 8.0 is obtained.
  • the temperature is increased to 92° C. and maintained at this level until the end of the reaction.
  • a new simultaneous addition of sodium silicate and sulfuric acid is carried out for 40 minutes in the stirred vessel, with a sodium silicate flow rate of 34 L/h, in a concentration of 235 g/L, and a sulfuric acid flow rate, having a concentration of 80 g/L, regulated in order to maintain the pH of the reaction medium at a value of 8.0.
  • reaction medium is adjusted to a pH of 3.9 in 5 minutes by sulfuric acid having a concentration of 80 g/L.
  • the slurry obtained is filtered and washed on a filter press (dry extract of the cake 20%). After dilution, the cake obtained is mechanically disintegrated, adding sodium aluminate (Na 2 O/Al 2 O 3 weight ratio 0.8), in an Al/SiO 2 ratio of 0.3% and sulfuric acid until a pH of 6.5 is reached.
  • the resulting slurry (having a dry extract of 11%) is spray dried using a turbine spray dryer.
  • the silica precipitation reaction is carried, out by sequencing a Hartridge-Roughton type stainless steel fast blender, with an inlet diameter d of 5 mm (FIGURE), and a stirred (160 rpm) stainless steel vessel having a volume of 170 L, in the following steps.
  • a sodium silicate solution (SiO 2 /Na 2 O weight ratio 3.45), having a concentration of 50 g/L and a temperature of 82° C., at a flow rate of 384 L/h, is added to the fast blender for 8 minutes and 30 seconds, simultaneously with sulfuric acid, having a concentration of 21 g/L and a temperature of 82° C., at a flow rate regulated in order to maintain the pH of the reaction medium at a value of 4.0.
  • This reaction medium is accommodated in the stirred vessel, into which a sodium silicate solution is introduced simultaneously at a flow rate regulated in order to maintain the pH of the reaction medium at a value of 4.4.
  • the temperature is increased to 82° C.
  • the feeds of the fast blender are interrupted and a sodium silicate solution is introduced into the stirred vessel until pH value of 8.0 is obtained.
  • the temperature is increased to 92° C. and maintained at this level until the end of the reaction.
  • a new simultaneous addition of sodium silicate and sulfuric acid is carried out for 40 minutes in the stirred vessel, with a sodium silicate flow rate of 35 L/h, in a concentration of 235 g/L, and a sulfuric acid flow rate, having a concentration of 80 g/L, regulated in order to maintain the pH of the reaction medium at a value of 8.0.
  • reaction medium is adjusted to a pH of 4.0 in 5 minutes by sulfuric acid having a concentration of 80 g/L.
  • the slurry obtained is filtered and washed on a filter press (dry extract of the cake 20%). After dilution, the cake obtained is mechanically disintegrated, adding sodium aluminate (Na 2 O/Al 2 O 3 weight ratio 0.8), in an Al/SiO 2 ratio of 0.3% and sulfuric acid until a pH of 6.5 is reached.
  • the resulting slurry (having a dry extract of 18.6%) is spray dried by means of a nozzle spray dryer.
  • the silica precipitation reaction is carried out by sequencing a Hartridge-Roughton type stainless steel fast blender, with an inlet diameter d of 5 mm (FIGURE), and a stirred (160 rpm) stainless steel vessel having a volume of 170 L, in the following steps.
  • a sodium silicate solution (SiO 2 /Na 2 O weight ratio 3.45), having a concentration of 50 g/L and a temperature of 78° C., at a flow rate of 376 L/h, is added to the fast blender for 8 minutes and 30 seconds, simultaneously with sulfuric acid, having a concentration of 21 g/L and a temperature of 78° C., at a flow rate regulated in order to maintain the pH of the reaction medium at a value of 3.9.
  • This reaction medium is accommodated in the stirred vessel, into which a sodium silicate solution is introduced simultaneously at a flow rate regulated in order to maintain the pH of the reaction medium at a value of 4.1.
  • the temperature is increased to 85° C.
  • the feeds of the fast blender are interrupted and a sodium silicate solution is introduced into the stirred vessel until pH value of 8.0 is obtained.
  • the temperature is increased to 92° C. and maintained at this level until the end of the reaction.
  • a new simultaneous addition of sodium silicate and sulfuric acid is carried out for 40 minutes in the stirred vessel, with a sodium silicate flow rate of 33 L/h, in a concentration of 235 g/L, and a sulfuric acid flow rate, having a concentration of 80 g/L, regulated in order to maintain the pH of the reaction medium at a value of 8.0.
  • reaction medium is adjusted to a pH of 3.9 in 5 minutes by sulfuric acid having a concentration of 80 g/L.
  • the slurry obtained is filtered and washed on a filter press (dry extract of the cake 20%). After dilution, the cake obtained is mechanically disintegrated, adding sodium aluminate (Na 2 O/Al 2 O 3 weight ratio 0.8), in an Al/SiO 2 ratio of 0.3% and sulfuric acid until a pH of 6.5 is reached.
  • the resulting slurry (having a dry extract of 11%) is spray dried using a turbine spray dryer.
  • the silica precipitation reaction is carried out by sequencing a Hartridge-Roughton type stainless steel fast blender, with an inlet diameter d of 5 mm (FIGURE), and a stirred (160 rpm) stainless steel vessel having a volume of 170 L, in the following steps.
  • a sodium silicate solution (SiO 2 /Na 2 O weight ratio 3.45), having a concentration of 50 g/L and a temperature of 86° C., at a flow rate of 376 L/h, is added to the fast blender for 8 minutes and 30 seconds, simultaneously with sulfuric acid, having a concentration of 21 g/L and a temperature of 86° C., at a flow rate regulated in order to maintain the pH of the reaction medium at a value of 3.9.
  • This reaction medium is accommodated in the stirred vessel, into which a sodium silicate solution is introduced simultaneously at a flow rate regulated in order to maintain the pH of the reaction medium at a value of 4.1.
  • the temperature is increased to 86° C.
  • the feeds of the fast blender are interrupted and a sodium silicate solution is introduced into the stirred vessel until pH value of 8.0 is obtained.
  • the temperature is increased to 92° C. and maintained at this level until the end of the reaction.
  • a new simultaneous addition of sodium silicate and sulfuric acid is carried out for 40 minutes in the stirred vessel, with a sodium silicate flow rate of 32 L/h, in a concentration of 235 g/L, and a sulfuric acid flow rate, having a concentration of 80 g/L, regulated in order to maintain the pH of the reaction medium at a value of 8.0.
  • reaction medium is adjusted to a pH of 4.0 in 5 minutes by sulfuric acid having a concentration of 80 g/L.
  • the slurry obtained is filtered and washed on a filter press (dry extract of the cake 20%). After dilution, the cake obtained is mechanically disintegrated, adding sodium aluminate (Na 2 O/Al 2 O 3 weight ratio 0.8), in an Al/SiO 2 ratio of 0.3% and sulfuric acid until a pH of 6.5 is reached.
  • the resulting slurry (having a dry extract of 11%) is spray dried using a turbine spray dryer.

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FR0611289A FR2910459B1 (fr) 2006-12-22 2006-12-22 Nouveau procede de preparation de silices precipitees par mise en oeuvre d'un melangeur rapide
PCT/EP2007/064473 WO2008077948A1 (fr) 2006-12-22 2007-12-21 Nouveau procede de preparation de silices precipitees par mise en oeuvre d'un melangeur rapide

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Cited By (4)

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US20120077902A1 (en) * 2010-09-24 2012-03-29 Pascal Patrick Steiner Pneumatic tire
DE102010039105B4 (de) * 2009-08-10 2016-12-22 The Yokohama Rubber Co., Ltd. Gummizusammensetzung zur Verwendung in Reifenlaufflächen und Verwendung der Gummizusammensetzung in einer Lauffläche eines Luftreifens
US9567230B2 (en) 2009-09-03 2017-02-14 Rhodia Operations Method for preparing precipitated silica
US11873218B2 (en) 2018-03-02 2024-01-16 Pörner Ingenieurgesellschaft M.B.H. Sustainable silicates and methods for their extraction

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FR2928363B1 (fr) * 2008-03-10 2012-08-31 Rhodia Operations Nouveau procede de preparation de silices precipitees, silices precipitees a morphologie, granulometrie et porosite particulieres et leurs utilisations, notamment pour le renforcement de polymeres
FR2962996B1 (fr) * 2010-07-23 2012-07-27 Rhodia Operations Nouveau procede de preparation de silices precipitees
FR2988383B1 (fr) * 2012-03-22 2017-06-09 Rhodia Operations Procede de preparation de silice precipitee mettant en oeuvre un malaxeur ou une extrudeuse
FR3017609B1 (fr) * 2014-02-14 2016-03-18 Rhodia Operations Nouveau procede de preparation de silices precipitees, nouvelles silices precipitees et leurs utilisations, notamment pour le renforcement de polymeres
JP6781106B2 (ja) * 2017-06-09 2020-11-04 東ソー・シリカ株式会社 ゴム補強充填用含水ケイ酸及びその製造方法
JP7069604B2 (ja) * 2017-08-28 2022-05-18 味の素株式会社 沈降シリカの製造法
EP3820816A1 (en) * 2018-07-13 2021-05-19 Rhodia Operations Precipitated silica with improved processing properties
CN109319794A (zh) * 2018-11-20 2019-02-12 福建省三明同晟化工有限公司 一种连续法制备沉淀二氧化硅的方法
EP3992147A1 (de) 2020-10-28 2022-05-04 Evonik Operations GmbH Gefällte kieselsäuren, verfahren zur deren herstellung und deren verwendung

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US2871099A (en) * 1955-02-03 1959-01-27 Basf Ag Process for the continuous production of hydrogels containing silicic acid
US3034914A (en) * 1959-05-05 1962-05-15 Pittsburgh Plate Glass Co Preparation of siliceous products
US3108892A (en) * 1960-12-05 1963-10-29 Pittsburgh Plate Glass Co Pigment process
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DE102010039105B4 (de) * 2009-08-10 2016-12-22 The Yokohama Rubber Co., Ltd. Gummizusammensetzung zur Verwendung in Reifenlaufflächen und Verwendung der Gummizusammensetzung in einer Lauffläche eines Luftreifens
US9567230B2 (en) 2009-09-03 2017-02-14 Rhodia Operations Method for preparing precipitated silica
US20120077902A1 (en) * 2010-09-24 2012-03-29 Pascal Patrick Steiner Pneumatic tire
US8312905B2 (en) * 2010-09-24 2012-11-20 The Goodyear Tire & Rubber Company Pneumatic tire
US11873218B2 (en) 2018-03-02 2024-01-16 Pörner Ingenieurgesellschaft M.B.H. Sustainable silicates and methods for their extraction

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