METHOD FOR PRODUCING AN ARTICLE FOR USE IN THE FOUNDRY INDUSTRY, CORRESPONDING GRANULAR MATERIAL AND KIT, APPARATUSES, AND USES

Abstract

The invention relates to a method for producing an article for use in the foundry industry, selected from a group consisting of granular material for producing a pourable additive, a solid pourable additive, an inorganic binder, and a molding material mixture. The invention also relates to a corresponding granular material comprising particulate amorphous silica and to a kit for producing an inorganic binder. The invention also relates to an apparatus for carrying out the method according to the invention and to a corresponding use of particulate amorphous silica and to the corresponding use of a granular material.

Claims

1. A process for producing an article for use in the foundry industry selected from the group consisting of granular material for production of a pourable additive for use as a constituent of an inorganic binder in the foundry industry, solid pourable additive for use as a constituent of an inorganic binder in the foundry industry, inorganic binder for use in the foundry industry, molding material mixture comprising an inorganic binder for use in the foundry industry, and moldings for use in the casting of metallic cast parts in the foundry industry, comprising the following steps for production of the article: producing or providing particulate amorphous silicon dioxide comprising silicon dioxide in a proportion of at least 80% by weight, based on the total mass of the particulate amorphous silicon dioxide, combining the particles of the particulate amorphous silicon dioxide in an enlargement step to give grains, so as to result in a granular material comprising a multitude of individual grains each comprising combined particles and each comprising a proportion of at least 30% by weight of particulate amorphous silicon dioxide, based on the mass of the respective grain, where the average grain diameter of the granular material is greater than 0.2 mm, determined by sieving.

2. The process as claimed in claim 1 for producing an article for use in the foundry industry selected from the group consisting of solid pourable additive for use as a constituent of an inorganic binder in the foundry industry, inorganic binder for use in the foundry industry, molding material mixture comprising an inorganic binder for use in the foundry industry, and moldings for use in the casting of metallic cast parts in the foundry industry, comprising the steps of: producing a granular material by a process as claimed in claim 1, comminuting the grains of the granular material, so as to result in a solid pourable additive.

3. The process as claimed in claim 1 for producing an article for use in the foundry industry selected from the group consisting of inorganic binder for use in the foundry industry, molding material mixture comprising an inorganic binder for use in the foundry industry, and moldings for use in the casting of metallic cast parts in the foundry industry, (i) comprising the steps of: producing the solid pourable additive by a process as claimed in claim 1, contacting the solid pourable additive produced with waterglass or suspending the solid pourable additive produced in waterglass, or (ii) comprising the steps of: producing a granular material by a process as claimed in claim 1, contacting the granular material produced with waterglass, in the presence or absence of refractory mold base material, and comminuting the grains of the granular material at the same time or thereafter.

4. The process as claimed in claim 1 for producing a molding material mixture comprising refractory mold base material and an inorganic binder comprising waterglass and particulate amorphous silicon dioxide for use in the foundry industry, comprising the steps of: producing an inorganic binder as per claim 1, and (i) at the same time mixing the constituents used for production of the inorganic binder with a refractory mold base material and/or (ii) thereafter mixing the inorganic binder produced with a refractory mold base material.

5. The process as claimed in claim 1, wherein, in the step of combining the particles of the particulate amorphous silicon dioxide in an enlargement step to give grains, so as to result in a granular material comprising a multitude of individual grains each comprising combined particles and each comprising a proportion of at least 30% by weight, preferably at least 40% by weight, more preferably at least 50% by weight, of particulate amorphous silicon dioxide, based on the mass of the respective grain, the average grain diameter of the granular material is greater than 0.5 mm, preferably greater than 1 mm, determined by sieving.

6. The process as claimed in claim 1, wherein the particulate amorphous silicon dioxide comprising silicon dioxide in a proportion of at least 80% by weight, based on the total mass of the particulate amorphous silicon dioxide, consists wholly or partly of particulate synthetic amorphous silicon dioxide.

7. The process as claimed in claim 1, wherein the proportion of silicon dioxide in the granular material as a whole, determined by means of x-ray fluorescence analysis, and the proportion of silicon dioxide in at least 90% of the grains of the granular material having a grain diameter greater than 1 mm, preferably greater than 0.5 mm, more preferably greater than 0.2 mm, in each case determined by means of sieving and subsequent x-ray fluorescence analysis, differs by not more than 30%, preferably differs by not more than 20%, more preferably differs by not more than 10%, based on the proportion of silicon dioxide in the granular material as a whole.

8. The process as claimed in claim 1, wherein, in the enlargement step, the particles of the particulate amorphous silicon dioxide are mixed and/or contacted with one, two or more further materials independently selected from the group consisting of: liquids, preferably liquid wetting agents and/or suspension media, preferably water, particulate materials, preferably particulate inorganic materials, preferably selected from the group consisting of oxides of aluminum, preferably aluminum oxide in the alpha phase, bauxite, oxides of zirconium, preferably zirconium(IV) oxide, mixed aluminum/silicon oxides, zinc oxide, barium sulfate, phosphorus compounds, sheet silicates, graphite, carbon black, glass beads, oxides of magnesium, borosilicates, ceramic hollow beads, oxidic boron compounds, preferably pulverulent oxidic boron compounds, and mixtures thereof, water-soluble materials, alkali metal hydroxides, surfactants, film formers, hydrophobizing agents, preferably organosilicon compounds, silanes, silicones and siloxanes, waxes, paraffins, metal soaps,  and carbohydrates.

9. The process as claimed in claim 8, wherein grains of the granular material that results from the enlargement step, preferably at least 90% of the grains of the granular material having a grain diameter greater than 1 mm, preferably greater than 0.5 mm, more preferably greater than 0.2 mm, in each case determined by means of sieving, (i) comprise particulate amorphous silicon dioxide and one, two, more than two or all of the further solid materials present in the enlargement step and/or (ii) comprise particulate amorphous silicon dioxide and one, two or more further materials independently selected from the group consisting of: particulate materials, preferably particulate inorganic materials, preferably selected from the group consisting of oxides of aluminum, preferably aluminum oxide in the alpha phase, bauxite, oxides of zirconium, preferably zirconium(IV) oxide, mixed aluminum/silicon oxides, zinc oxide, barium sulfate, phosphorus compounds, sheet silicates, graphite, carbon black, glass beads, oxides of magnesium, borosilicates, ceramic hollow beads, oxidic boron compounds, preferably pulverulent oxidic boron compounds, and mixtures thereof, water-soluble materials, alkali metal hydroxides, surfactants, film formers, hydrophobizing agents, preferably organosilicon compounds, silanes, silicones and siloxanes, waxes, paraffins, metal soaps, and carbohydrates.

10. The process as claimed in claim 1, wherein the producing of particulate amorphous silicon dioxide comprising silicon dioxide in a proportion of at least 80% by weight, based on the total mass of the particulate amorphous silicon dioxide, comprises the step of: mixing two or more different types of particulate amorphous silicon dioxide, where the two or more types differ by their particle size distribution and/or their chemical composition.

11. The process as claimed in claim 10, (i)—wherein a first type of particulate amorphous silicon dioxide has a particle size distribution having a median in the range from 0.1 to 0.4 μm, determined by laser scattering, and wherein a further type of particulate amorphous silicon dioxide has a particle size distribution having a median in the range from 0.7 to 1.5 μm, determined by laser scattering, and/or (ii)—wherein one, two, more than two or all of the different types of particulate amorphous silicon dioxide is selected or are independently selected from the group consisting of particulate synthetic amorphous silicon dioxide containing silicon dioxide in a proportion of at least 80% by weight, based on the total mass of the particulate synthetic amorphous silicon dioxide, and at least carbon as secondary constituent, preferably producible by reducing quartz in an arc furnace; particulate synthetic amorphous silicon dioxide comprising oxidic zirconium as secondary constituent and preferably producible by thermal breakdown of ZrSiO.sub.4 particulate synthetic amorphous silicon dioxide producible by oxidizing metallic silicon by means of an oxygenous gas; particulate synthetic amorphous silicon dioxide producible by quenching a silicon dioxide melt.

12. The process as claimed in claim 10, wherein at least 90% of the grains of the granular material having a grain diameter greater than 0.2 mm, preferably greater than 0.5 mm, more preferably greater than 1 mm, in each case determined by sieving, comprise both or at least two of the different types of particulate amorphous silicon dioxide.

13. The process as claimed in claim 1, wherein the enlargement step comprises one or more measures independently selected from the group consisting of: granulating extruding and agglomerating.

14. A granular material having an average grain diameter greater than 0.2 mm, determined by sieving, for production of a pourable additive for use as a constituent of an inorganic binder in the foundry industry, comprising particulate amorphous silicon dioxide, (a) wherein the granular material additionally comprises one, two or more further materials independently selected from the group consisting of: particulate materials, preferably particulate inorganic materials, preferably selected from the group consisting of oxides of aluminum, preferably aluminum oxide in the alpha phase, bauxite, oxides of zirconium, preferably zirconium(IV) oxide, mixed aluminum/silicon oxides, zinc oxide, barium sulfate, phosphorus compounds, sheet silicates, graphite, carbon black, glass beads, oxides of magnesium, borosilicates, ceramic hollow beads, oxidic boron compounds, preferably pulverulent oxidic boron compounds, and mixtures thereof, water-soluble materials, alkali metal hydroxides, surfactants, film formers, hydrophobizing agents, preferably organosilicon compounds, silanes, silicones and siloxanes, waxes, paraffins, metal soaps, and carbohydrates, wherein at least 90% of the grains of the granular material having a grain diameter greater than 0.2 mm, preferably greater than 0.5 mm, more preferably greater than 1 mm, in each case determined by sieving, comprise particulate amorphous silicon dioxide, and one, two or more of said further materials, and/or (b) wherein the particulate amorphous silicon dioxide comprises a proportion of at least 80% by weight of silicon dioxide, based on the total mass of the particulate amorphous silicon dioxide, preferably consisting wholly or partly of particulate synthetic amorphous silicon dioxide, and/or (c) wherein the proportion of silicon dioxide in the granular material as a whole, determined by means of x-ray fluorescence analysis, and the proportion of silicon dioxide in at least 90% of the grains of the granular material having a grain diameter greater than 1 mm, in each case determined by means of sieving and subsequent x-ray fluorescence analysis, differs by not more than 30%, preferably differs by not more than 20%, more preferably differs by not more than 10%, based on the proportion of silicon dioxide in the granular material as a whole, and/or (d) wherein, in the granular material, the particulate amorphous silicon dioxide comprises two or more different types of particulate amorphous silicon dioxide, where the two or more types differ by their chemical composition, wherein preferably one, two, more than two or all of the different types of particulate amorphous silicon dioxide is selected or are independently selected from the group consisting of particulate synthetic amorphous silicon dioxide containing silicon dioxide in a proportion of at least 80% by weight, based on the total mass of the particulate synthetic amorphous silicon dioxide, and at least carbon as secondary constituent, preferably producible by reducing quartz in an arc furnace; particulate synthetic amorphous silicon dioxide comprising oxidic zirconium as secondary constituent and preferably producible by thermal breakdown of ZrSiO.sub.4 particulate synthetic amorphous silicon dioxide producible by oxidizing metallic silicon by means of an oxygenous gas; particulate synthetic amorphous silicon dioxide producible by quenching a silicon dioxide melt and/or (e) wherein the granular material is producible by a process as claimed in claim 1.

15. A kit for production of an inorganic binder, at least comprising, as components in a mutually spatially separate arrangement, a granular material as claimed in claim 14 and a solution or dispersion comprising waterglass.

16. An apparatus for performing a process as claimed in claim 1, comprising a reservoir vessel containing particulate amorphous silicon dioxide, comprising silicon dioxide in a proportion of at least 80% by weight, based on the total mass of the particulate amorphous silicon dioxide, a mixing or contacting device for mixing or contacting the particulate amorphous silicon dioxide with one, two or more further materials, a device for granulating, extruding and/or agglomerating the particulate amorphous silicon dioxide that has been mixed or contacted with one, two or more further materials.

17. The apparatus as claimed in claim 16, additionally comprising one or more apparatus elements selected from the group consisting of device for transferring particulate amorphous silicon dioxide from the reservoir vessel into the mixing or contacting apparatus, one or more reservoir vessels containing liquid, preferably liquid wetting agent and/or suspension medium, preferably water, one or more reservoir vessels containing particulate material, preferably particulate inorganic material, preferably selected from the group consisting of oxides of aluminum, preferably aluminum oxide in the alpha phase, bauxite, oxides of zirconium, preferably zirconium(IV) oxide, mixed aluminum/silicon oxides, zinc oxide, barium sulfate, phosphorus compounds, sheet silicates, graphite, carbon black, glass beads, oxides of magnesium, borosilicates, ceramic hollow beads, oxidic boron compounds, preferably pulverulent oxidic boron compounds, and mixtures thereof, one or more reservoir vessels containing a water-soluble material, one or more reservoir vessels containing one or more surfactants, one or more reservoir vessels containing one or more hydrophobizing agents, one or more reservoir vessels containing one or more carbohydrates.

18. The apparatus as claimed in claim 16, additionally comprising a device for dispensing or transporting granular material produced.

19. Method of making a granular material as claimed in claim 14, comprising the use of particulate amorphous silicon dioxide.

20. Method of producing a solid pourable additive with homogenized grain composition comprising a granular material as claimed in claim 14, wherein the homogenized grain composition if for use as a constituent of an inorganic binder in the foundry industry.

Description

EXAMPLE 1—METHODOLOGY OF DETERMINATION OF PARTICLE SIZE DISTRIBUTION BY MEANS OF LASER SCATTERING

[0519] The selection of the substances in this example is merely illustrative, and it is also possible to determine particle size distributions or medians of other particulate species to be used in the context of the present invention by means of laser scattering according to the procedure in this example.

[0520] 1.1 Sample Preparation:

[0521] By way of example, particle size distributions of silica fume particles (CAS number: 65012-64-2; particulate amorphous silicon dioxide) that are commercially available (RW Silicium GmbH) and in particulate powder form from Si production were determined.

[0522] In each case, about 1 teaspoon of this particulate amorphous silicon dioxide was admixed with about 100 mL of demineralized water, and the resultant mixture was stirred with a magnetic stirrer (IKAMAG RET) at a stirrer speed of 500 revolutions per minute for 30 seconds. Subsequently, an ultrasound probe (from Hielscher; model: UP200HT) preadjusted to 100% amplitude, equipped with a S26d7 sonotrode (from Hielscher), was immersed into the sample, and the sample was sonicated therewith. The sonication was continuous (not pulsed). For the silica fume particles examined, optimal sonication times of 300 seconds were chosen, which were determined beforehand as described in point 1.3 below of example 1.

[0523] 1.2 Laser Scattering Measurements:

[0524] The measurements were conducted with a Horiba LA-960 instrument (LA-960 hereinafter). For the measurements, circulation speed was set to 6, stirrer speed to 8, data recording for the sample to 30 000, convergence factor to 15, the mode of distribution to volume, and refractive index (R) to 1.50-0.01i (1.33 for demineralized water dispersion medium) and refractive index (B) to 1.50-0.01i (1.33 for demineralized water dispersion medium). Laser scattering measurements were conducted at room temperature (20° C. to 25° C.).

[0525] The measurement chamber of the LA-960 was filled to an extent of three quarters with demineralized water (maximum fill level). Then the stirrer was started at the set speed, the circulation was switched on and the water was degassed. Subsequently, a zero measurement was conducted with the parameters specified.

[0526] A disposable pipette was then used to take a 0.5-3.0 mL sample centrally from the sample prepared according to point 1.1 of example 1 immediately after the ultrasound treatment. Subsequently, the complete contents of the pipette were introduced into the measurement chamber, such that the transmittance of the red laser was between 80% and 90% and the transmittance of the blue laser was between 70% and 90%. Then the measurement was started. The measurements were evaluated in an automated manner on the basis of the parameters specified.

[0527] For the silica fume particles examined from Si production, a particle size distribution was ascertained with a median rounded to the second post-decimal place.

[0528] 1.3 Determination of Optimal Sonication Time:

[0529] The optimal duration of ultrasound sonication, which is dependent on the type of sample, is ascertained by conducting a measurement series with different sonication times for each particulate species. This is done by extending the sonication time, starting from 10 seconds, by 10 seconds each time for every further sample, and determining the respective particle size distribution by means of laser scattering (LA-960) immediately after the end of sonication as described in point 1.2 of example 1. With increasing duration of sonication, the median ascertained in the particle size distribution falls at first, before ultimately rising again at longer sonication times. For the ultrasound sonications described in point 1.1 of example 1, the sonication time chosen was that at which, in these measurements series, the lowest median of the particle size distribution was determined for the particle species; this sonication time is the “optimal” sonication time.

EXAMPLE 2—PRODUCTION METHOD FOR GRANULAR MATERIALS

[0530] 10 kg of synthetic particulate amorphous silicon dioxide (in powder form, particle size <1.5 μm; e.g. Microsilica POS B-W 90 LD (Possehl Erzkontor GmbH) or silica fume (Doral Fused Materials Pty., Ltd.); production process in each case: production of ZrO.sub.2 and SiO.sub.2 from ZrSiO.sub.4) are introduced into a plowshare mixer (from Gebrüder Lödige Maschinenbau GmbH, model L50), and the plowshare mixer, for mixing, is operated at a speed of rotation of the plowshare shaft of 180 revolutions per minute and of the bladed head of 3000 revolutions per minute. During the mixing, water is fed into the synthetic particulate amorphous silicon dioxide in several steps: 0.25 kg of water followed by a mixing time of 60 seconds, then an additional 0.5 kg of water followed by a mixing time of a further 240 seconds, then an additional 0.5 kg of water followed by a mixing time of a further 120 seconds, and then an additional 1.0 kg of water followed by a mixing time after a further mixing time of 180 seconds.

[0531] The suspension thus produced is dripped by means of a pipette in individual droplets onto a commercial aluminum foil (which has optionally been sprayed with separating agent) heated to 250° C. on a hotplate and dried, such that the particles of the powder used combine to form grains and result in a granular material of the invention. The hotplate is preferably protected here from soiling with a further layer of aluminum foil (arranged beneath the layer that comes into contact with the suspension).

[0532] The proportion by mass of the particles having a size of less than 20 μm, determined by means of laser scattering, in the granular material is lower than in the particulate amorphous silicon dioxide.

EXAMPLE 3—BULK DENSITY; REDUCED EVOLUTION OF DUST

[0533] Bulk density is determined with a laboratory balance (measurement uncertainty ±0.1 g), a metal measuring cylinder having a volume of (100±0.5) mL and an internal diameter of (45±5) mm, and a funnel (according to DIN EN ISO 60) with a closed lower opening.

[0534] The funnel is secured centrally above the measuring cylinder at a height of 20 mm to 30 mm, and the sample is mixed well. About 120 mL to 130 mL of the sample is introduced into the funnel. The closure of the funnel is opened quickly, such that the sample material drops into the cylinder. Excess sample material is stripped off the cylinder with the aid of a straight-edged article, and then the contents of the cylinder are weighed; the mass of the contents of the cylinder is m.sub.sample.

[0535] The evaluation is made by the following formula:

[00002]$\mathrm{Bulk}\mathrm{density}\left[\frac{g}{L}\right]=m_{\mathrm{sample}}\left[g\right].Math.10\left[\frac{1}{L}\right]$

[0536] The result is reported to 1 g/L.

[0537] According to example 2, synthetic particulate amorphous silicon dioxide having a bulk density of 550 g/L was used to produce a granular material. After drying, the granular material of the invention thus obtained had an average grain diameter of 6 mm and a bulk density of 950 g/L.

[0538] When poured, the granular material showed much lower evolution of (fine) dust than the starting material, the synthetic particulate amorphous silicon dioxide having a bulk density of 550 g/L.

EXAMPLE 4—EXAMINATION OF ONE-HOUR STRENGTH OF DIFFERENT TEST BARS

[0539] 4.1 Production of a Molding Material Mixture 4-A

[0540] 0.80 part by weight of synthetic particulate amorphous silicon dioxide having a bulk density of about 550 g/L (pulverulent; non-granulated; e.g. Microsilica POS B-W 90 LD (Possehl Erzkontor GmbH) or silica fume (Doral Fused Materials Pty., Ltd.); production process in each case: production of ZrO.sub.2 and SiO.sub.2 from ZrSiO.sub.4) was mixed manually with 100 parts by weight of H-S 00232 sand (quartz sand, from Quarzwerke GmbH, AFS grain fineness number 47). Then 2.00 parts by weight of a water glass-based liquid binder (commercial material named Cordis 9032; Hüttenes-Albertus Chemische Werke GmbH) was added and all components were mixed with one another for 120 s in a bull mixer (RN 10/20 type, from Morek Multiserw) at 220 revolutions per minute, such that the materials used were distributed homogeneously, and so as to result in a molding material mixture.

[0541] 4.2 Production of a Molding Material Mixture 4-B

[0542] Synthetic particulate amorphous silicon dioxide having a bulk density of 550 g/L (identical to the material used in example 4.1) and water were used according to example 2 to produce a granular material. The granular material thus produced was ground in a mixer (from Bosch, Universal Plus MUM 6N11 food processor) for 10 s so as to result in a solid pourable additive.

[0543] 0.80 part by weight of this solid pourable additive was mixed manually with 100 parts by weight of H-S 00232 sand (quartz sand, from Quarzwerke GmbH, AFS grain fineness number 47). Then 2.00 parts by weight of a water glass-based liquid binder (commercial material named Cordis 9032; Hüttenes-Albertus Chemische Werke GmbH) was added and all components were mixed with one another for 120 s in a bull mixer (RN 10/20 type, from Morek Multiserw) at 220 revolutions per minute, such that the materials used were distributed homogeneously, and so as to result in a molding material mixture.

[0544] 4.3 Production of a Molding Material Mixture 4-C

[0545] From 20.05 kg of synthetic particulate amorphous silicon dioxide having a bulk density of about 550 g/L (identical to the material used in example 4.1) was introduced into a plowshare mixer (from Gebrüder Lödige Maschinenbau GmbH, model L50). 3 kg of water was fed into the synthetic particulate amorphous silicon dioxide, and the plowshare mixer was operated at a speed of rotation of the plowshare shaft of 180 revolutions per minute and of the bladed head of 3000 revolutions per minute for 120 seconds. Then the bladed head was switched off and mixing was continued at a speed of rotation of the plowshare shaft of 180 revolutions per minute, such that a soft granular material was formed.

[0546] A portion of the still-moist soft granular material was then dried to constant weight at 105° C., so as to result in a (dried) granular material. The cooled dried material was then classified by means of a sieving tower in accordance with VDG-Merkblatt P 27, October 1999, and the fractions <125 μm were discarded. The sieving yield was about 85%.

[0547] When poured, the classified granular material showed much lower evolution of (fine) dust than the starting material, the particulate amorphous silicon dioxide having a bulk density of about 550 g/L.

[0548] The classified granular material thus produced was ground in a mixer (from Bosch, Universal Plus MUM 6N11 food processor) for 10 s so as to form a solid pourable additive.

[0549] 0.80 part by weight of this solid pourable additive was mixed manually with 100 parts by weight of H-S 00232 sand (quartz sand, from Quarzwerke GmbH, AFS grain fineness number 47). Then 2.00 parts by weight of a water glass-based liquid binder (commercial material named Cordis 9032; Hüttenes-Albertus Chemische Werke GmbH) was added and all components were mixed with one another for 120 s in a bull mixer (RN 10/20 type, from Morek Multiserw) at 220 revolutions per minute, such that the materials used were distributed homogeneously, and so as to result in a molding material mixture.

[0550] 4.4 Production of Test Bars

[0551] Molding material mixtures 4-A, 4-B and 4-C produced according to points 4.1, 4.2 and 4.3 of example 4 were each formed to test bars having dimensions of 22.4 mm×22.4 mm×185 mm. For this purpose, the respective molding material mixtures were introduced with compressed air (4 bar) and a shooting time of 3 seconds into a mold for test bars having a temperature of 160° C. Subsequently, the test bars were subjected to hot curing at 160° C. without gas supply for 30 seconds. Thereafter, the mold was opened, and the cured test bars were removed and stored for cooling.

[0552] 4.5 Determination of One-Hour Strength

[0553] The test bars produced from molding material mixtures 4-A, 4-B and 4-C according to point 4.4 of example 4, after a cooling time of one hour, were introduced into a Georg Fischer strength tester, equipped with a 3-point bending device (from Morek Multiserw), and the force that led to fracture of the test bar was measured. The value read off (in N/cm.sup.2) indicated the one-hour strength. Results are shown in table 1, with the respective one-hour strength figure corresponding to a median from 6 individual measurements.

TABLE-US-00001 TABLE 1 Molding material One-hour strength mixture no. (N/cm.sup.2) 4-A 500 4-B 520 4-C 520

[0554] The results listed in table 1 show that test bars produced using a granular material (produced by a process of the invention) or a solid pourable additive (produced by a process of the invention) surprisingly have elevated one-hour strength.

EXAMPLE 5—PRODUCTION OF GRANULAR MATERIALS WITH HOMOGENEOUS DISTRIBUTION OF MULTIPLE ADDITIVES

[0555] Analogously to the production method from example 2, granular materials were produced in a multitude of in-house experiments, with addition of one or more of the following substances as a further material, in each case in addition to the particulate amorphous silicon dioxide used: [0556] liquids, preferably liquid suspension media, preferably water, [0557] particulate materials, preferably particulate inorganic materials, preferably selected from the group consisting of oxides of aluminum, preferably aluminum oxide in the alpha phase, bauxite, oxides of zirconium, preferably zirconium(IV) oxide, mixed aluminum/silicon oxides, zinc oxide, barium sulfate, phosphorus compounds, sheet silicates, graphite, carbon black, glass beads, oxides of magnesium, borosilicates, ceramic hollow beads, oxidic boron compounds, preferably pulverulent oxidic boron compounds, and mixtures thereof, [0558] water-soluble materials, [0559] alkali metal hydroxides, [0560] surfactants, preferably selected from the group consisting of: [0561] oleyl sulfate, stearyl sulfate, palmityl sulfate, myristyl sulfate, lauryl sulfate, decyl sulfate, octyl sulfate, 2-ethylhexyl sulfate, 2-ethyloctyl sulfate, 2-ethyldecyl sulfate, palmitoleyl sulfate, linolyl sulfate, lauryl sulfonate, 2-ethyldecyl sulfonate, palmityl sulfonate, stearyl sulfonate, 2-ethylstearyl sulfonate, linolyl sulfonate, hexyl phosphate, 2-ethylhexyl phosphate, capryl phosphate, lauryl phosphate, myristyl phosphate, palmityl phosphate, palmitoleyl phosphate, oleyl phosphate, stearyl phosphate, poly(ethane-1,2-diyl)phenol hydroxyphosphate, poly(ethane-1,2-diyl)stearyl phosphate, poly(ethane-1,2-diyl)oleyl phosphate, polycarboxylate ethers in water (Melpers 0030, from BASF), modified polyacrylate in water (Melpers VP 4547/240 L, from BASF), 2-ethylhexyl sulfate in water (Texapon EHS, from Cognis), polyglucoside in water (Glukopon 225 DK, from Cognis), sodium octylsulfate in water (Texapon 842, from Lakeland), modified carboxylate ethers (Castament ES 60, solid-state, from BASF). [0562] film formers, preferably polyvinylalcohol and/or acrylic acid, [0563] rheological additives (thickeners, suspension aids), preferably selected from the group consisting of: [0564] swellable clays, preferably sodium bentonite or attapulgite/palygorskite, [0565] swellable polymers, preferably cellulose derivatives, especially carboxymethyl, methyl, ethyl, hydroxyethyl and hydroxypropyl cellulose, plant mucilages, polyvinylpyrrolidone, pectin, gelatin, agar-agar, polypeptides and/or alginates, [0566] hydrophobizing agents, preferably organosilicon compounds, silanes, silanols, preferably trimethylsilanol, silicones and siloxanes, preferably polydimethylsiloxane, waxes, paraffins, metal soaps,  and [0567] carbohydrates.

[0568] Granular materials were obtained in an analogous manner in each case. The granular materials obtained can each be processed by grinding to give solid pourable additive. Granular materials or solid pourable additives were each processed successfully to give molding material mixtures, and these were processed further to give test bars.