JP2022543468A - Methods, corresponding particulates and kits, apparatus and uses for manufacturing articles for use in the foundry industry - Google Patents

Abstract

The present invention produces an article for use in the foundry industry selected from the group consisting of granules for producing injectable additives, solid injectable additives, inorganic binders and molding material mixtures. about the method for The present invention also relates to kits for making corresponding granules and inorganic binders comprising particulate amorphous silica. The invention also relates to a device for carrying out the process according to the invention and the corresponding use of particulate amorphous silica and the corresponding use of granules.

Description

The present invention produces articles for use in the foundry industry selected from the group consisting of granules for the production of injectable additives, solid injectable additives, inorganic binders and molding material mixtures. about the process for Further details of the process of the invention will be apparent from the appended claims and the following description. The invention additionally relates to corresponding granules comprising particulate amorphous silicon dioxide. The invention further relates to kits for the production of inorganic binders. The invention also relates to an apparatus for carrying out the process of the invention. The invention further relates to the corresponding use of particulate amorphous silicon dioxide. The invention additionally relates to the corresponding use of the granules. Details of each will be apparent from the appended claims and the following description.

Lost mold casting is a commonly used process for the production of near net shape parts. After casting, the mold is destroyed and the cast parts are removed. Lost molds are molds, and therefore negatives, that contain cavities in which casting takes place, thereby obtaining finished cast parts. The inner contour of future cast parts is formed by the core. During manufacture of the mold, a model of the cast part to be manufactured forms a cavity in the molding material.

In contrast to sand casting methods in which the mold (lost mold) is destroyed after casting to remove the cast parts, permanent metallic molds, for example made from cast iron or cast steel, are used after removal of the cast parts. can be reused for casting. Die casting can also be used, in which a liquid metal melt is injected into a die casting mold under high pressure with a high mold filling speed. The casting method described above is also preferred with respect to the present invention. The molding substrates used for the molds and cores (in sand casting processes with lost molds) are primarily refractory particulate materials, such as washed classified silica sand. For the production of molds, molding substrates are bound together by inorganic or organic binders. The binder forms a firm bond between the particles of the molding substrate so that the required mechanical stability of the mold or core is obtained. The refractory molded substrate premixed with a binder is preferably in free-flowing form so that it can be introduced into a suitable cavity and compressed therein. The molding material is compressed to increase strength.

The mold and core must meet various requirements. During the actual casting operation they must first of all have sufficient strength and temperature stability to be able to contain the liquid metal in the cavities formed by one or more (partial) molds. . After starting the solidification operation, the mechanical stability of the cast part is ensured by a solidified metal layer that forms along the walls of the mold.

It is assumed that the material of the mold will change under the influence of the heat given off by the metal in such a way that it loses its mechanical strength, i.e. the bond between the individual particles of the refractory material is lost. . In the ideal case, the mold and core can be easily removed from the cast part and decomposed again to form fine sand with correspondingly good disintegration properties.

Inorganic binders have been known for a long time, especially those based on water glass. Three different methods in particular are available for curing water glass, which may be combined: (i) passage of gas, such as _CO2 , air or a combination of the two, (ii) liquid or solid curing. addition of agents, such as certain esters, and (iii) thermal curing, such as in the so-called hot-box method or by microwave treatment.

However, the use of inorganic binder systems is often associated with other typical disadvantages.

For example, it is relatively common for castings made from inorganic binders to exhibit low strength unless appropriate special measures are taken. This is particularly evident immediately after removal of the core or mold or casting from the mould. Strength at this point ("hot strength" or "instant strength") is particularly important for safe handling of the core or foam during removal from the mold. Also important is high "cold strength" (i.e. strength after full hardening of the core or mold) so that the desired cast parts can be produced with minimal levels of casting defects.

EP 1 802 409 B1 describes a molding material mixture for producing molds for metalworking, comprising at least a refractory molding substrate, a binder based on water glass and a proportion of particulate synthetic amorphous dioxide A molding compound mixture is disclosed, characterized in that silicon is added to the molding compound mixture.

DE 102013111626 A1 describes a molding material mixture for producing molds or cores comprising at least a refractory molding substrate, water glass as binder, particulate amorphous silicon dioxide and one Molding material mixtures containing the above powdered boron oxide compounds are disclosed. This document further discloses that the addition of a boron compound to the molding compound mixture improves the moisture stability of cores and molds produced therewith.

WO 2014/202042 A1 is a molding material mixture for producing molds and cores for metalworking, comprising at least one refractory molding substrate, particulate amorphous SiO ₂ , water glass and Molding material mixtures containing lithium compounds are disclosed. This document further discloses that the addition of a lithium compound to the molding compound mixture improves the moisture stability of moldings produced therewith.

DE 10 2012 104 934 A1 describes a molding compound mixture for producing molds for metalworking, comprising at least a refractory molding substrate, a binder based on water glass and barium sulphate. is disclosed.

DE 102012113073 A1 describes a molding compound mixture for producing foams and cores for metalworking, comprising at least a) a refractory molding substrate, b) an inorganic binder and c) at least one particulate metal oxide, wherein the particulate metal oxide is at least one alpha-phase aluminum oxide and/or at least one mixed aluminum/silicon oxide excluding mixed aluminum/silicon oxide having a sheet silicate structure Disclosed is a molding material mixture comprising or consisting of

DE 102012113074 A1 describes a molding material mixture for producing foams and cores for metalworking, comprising at least one refractory molding substrate, an organic binder and at least one particulate admixture. A molding material mixture comprising metal oxides is disclosed. Aluminum and zirconium oxides are used in a particular manner.

DE 102017107531 A1 discloses a process for manufacturing molds, cores and molded substrates regenerated therefrom. Particulate sheet silicates are used in a particular manner.

EP 2 104 580 B1 describes a molding material mixture for producing molds for metalworking, comprising at least a refractory molding substrate, a binder based on water glass; proportions of silicon dioxide, aluminum oxide, A molding material mixture is disclosed comprising particulate metal oxides selected from the group of titanium oxide and zinc oxide. A carbohydrate is added to the molding material mixture.

EP 2 097 192 B1 describes a molding material mixture for producing molds for metalworking, comprising at least a refractory molding substrate, a binder based on water glass; proportions of silicon dioxide, aluminum oxide, A molding material mixture is disclosed comprising particulate metal oxides selected from the group of titanium oxide and zinc oxide. A proportion of a phosphorus compound is added to the molding compound mixture.

DE 102012020509 A1 describes a molding compound mixture for producing molds and cores for metalworking, comprising at _least a refractory molding substrate, an inorganic binder and _ZrSiO4 to ZrO2 and _SiO2 . It discloses a molding compound mixture comprising particulate amorphous SiO ₂ that can be produced by pyrolysis to .

DE 10 2012 020 510 A1 describes a molding material mixture for producing molds and cores for metalworking, comprising at least a refractory molding substrate, an inorganic binder and oxidation of metallic silicon with an oxygen-containing gas. discloses a molding compound mixture comprising particulate amorphous SiO ₂ producible by the company.

DE 10 2012 020 511 A1 describes a molding material mixture for producing molds and cores for metalworking, comprising at least a refractory molding substrate, an inorganic binder and crystalline quartz by melting and rapid A molding compound mixture containing particulate amorphous SiO ₂ that can be produced by recooling is disclosed.

DE 102 01 202 0073 A1 describes a molding material mixture for producing molds and cores for metalworking, comprising at least a refractory molding substrate, an inorganic binder and oxidation of metallic silicon with an oxygen-containing gas. discloses a molding compound mixture comprising particulate amorphous SiO ₂ producible by the company.

WO 2009/056320 is a molding material mixture for producing molds for metalworking, comprising at least a refractory molding substrate, a binder based on water glass; proportions of silicon dioxide, aluminum oxide , a molding material mixture comprising particulate metal oxides selected from the group of titanium oxide and zinc oxide. A proportion of at least one surface-active substance is added to the molding compound mixture.

The patent documents identified above already disclose molding compound mixtures containing particulate amorphous SiO ₂ . It is also known that by starting from a specific base formulation and adding selected additives it is possible to influence the proportions of the molding material mixture and the properties of the resulting moldings.

In the foundry industry, binder and molding material mixtures containing particulate amorphous silicon dioxide and optionally further solid additives are used, and in fact hitherto there are additional health risks arising from contamination of the breathing air. There is a need to simultaneously minimize the inconvenience associated with individual weighing and mixing associated with . At the same time, it must be ensured that repeatedly produced binder and molding compound mixtures always have the same composition and always have the same product properties.

In addition, the use of substances that do not have long-term stability in water glass, even in gel or liquid form, as constituents of the corresponding binder and molding material mixtures without the need for any additional metering steps. is required.

Furthermore, for the molding material mixture without the need for any additional metering steps and without differences in the composition of the molding material mixture formed depending on, for example, the fill level in the storage container of particulate matter. There is a need to use various particulate materials, each with a very different particle size distribution, as additives for the.

Furthermore, there is a need to add solid and liquid additives for molding compound mixtures to molding compound mixtures in fixed relative proportions to each other and by a single general metering step.

Very particularly additives for molding material mixtures without the need for an additional metering step for every ingredient added and without having to deal with additional problems when storing the additive. There is a need to be able to combine the known positive properties of

The invention is defined in the claims and described in detail below.

The invention relates, in its sections, to a process for manufacturing articles for use in the foundry industry, granules, equipment for carrying out the process, the use of particulate amorphous silicon dioxide and the use of the granules. Any embodiment, aspect or feature described or described as preferred in connection with one of these divisions is correspondingly or similarly applicable to each other division, and vice versa.

Unless otherwise stated, any preferred aspect or embodiment of the invention and various sections thereof may be combined with other aspects or embodiments of the invention and various sections thereof, especially other preferred aspects or embodiments. By combining the respective preferred aspects or embodiments with each other, again preferred aspects or embodiments of the invention are obtained.

1 shows a flow diagram of a first embodiment of the process 100 of the present invention for producing a molding material mixture 107 for use in the foundry industry. Figure 2 shows a flow diagram of a second embodiment of the process 200 of the present invention for producing a molding material mixture 209 for use in the foundry industry. FIG. 3 shows a flow diagram of another embodiment of the process 300 of the present invention for producing a molding material mixture 309 for use in the foundry industry.

In a first aspect of the invention,
- granules for the production of injectable additives for use as components of mineral binders in the foundry industry,
- solid injectable additives for use as components of inorganic binders in the foundry industry,
- inorganic binders for use in the foundry industry,
- molding material mixtures containing inorganic binders for use in the foundry industry; and - moldings (especially cores, molds and feeders) for use in the foundry industry for casting metal casting parts.
A process for manufacturing an article for use in the foundry industry selected from the group consisting of the following steps for manufacturing the article:
- Particulate amorphous silicon dioxide comprising at least 80% by weight, preferably at least 90% by weight of silicon dioxide, based on the total weight of the particulate amorphous silicon dioxide producing or providing silicon dioxide;
- a plurality of individual grains, each comprising combined grains and containing at least 30% by weight, preferably at least 40% by weight, more preferably at least 50% by weight, based on the mass of each grain combining the particles of particulate amorphous silicon dioxide in an enlarging step to provide grains to provide a grain comprising a plurality of individual grains each containing a proportion of particulate amorphous silicon dioxide; The above goals are achieved and the problems are solved in whole or in part by a process comprising steps in which the average particle size of the material is greater than 0.2 mm as determined by sieving.

Granules, solid injectable additives, inorganic binders and molding material mixtures are each intermediate products as they are produced continuously (in the order specified) during the production of the mold or core. Each of these intermediate products can be stored or shipped individually.

Accordingly, the term "particulate", in relation to the above definition, is understood to mean the whole of the plurality of granules defined above.

A grain, as used herein, is the product of a planned expansion step and contains particulate amorphous silicon dioxide (and optionally further materials). The grains are thus in each case composites, eg aggregates or aggregates.

The term "particulate" preferably means particles of a solid powder (including dust), which are preferably pourable and therefore also sievable.

The particulate amorphous silicon dioxide used can be of both the synthetically produced type (eg, as defined in the first recognized prior art) and the naturally occurring type. The latter are known, for example from DE 10 2007 045 649 A1, but are often unfavorable because they contain a significant crystalline component and are therefore classified as carcinogenic. .

"Particulate amorphous silicon dioxide containing at least 80% by weight of silicon dioxide, based on the total weight of particulate amorphous silicon dioxide" is preferably particulate synthetic amorphous silicon dioxide. Depending on the source or preparation process, natural and/or synthetic amorphous silicon dioxide contains up to 50% by weight of secondary components, ie crystalline silicon dioxide and/or substances that are not silicon dioxide. Thus, commercially available (synthetic or natural) "particulate amorphous silicon dioxide" typically contains, in addition to silicon dioxide, a proportion of one or more further inorganic oxides and an unavoidable impurity content of Including percentage. In the context of the present invention, synthetic particulate amorphous dioxide containing a proportion of secondary components of less than 30% by weight and/or a proportion of silicon dioxide of at least 80% by weight, each based on the total weight of particulate amorphous silicon dioxide Preference is given to silicon, very particular preference to particulate synthetic amorphous silicon dioxide which contains a proportion of secondary components of less than 20% by weight and/or a proportion of silicon dioxide of at least 90% by weight.

Typically and optionally, the particulate amorphous silicon dioxide produced or provided preferably comprises particles in the form of dust.

The proportion of particulate amorphous silicon dioxide in the grains of the granules (after appropriate sample treatment, in particular after sieving according to VDG Merkblatt P 27, see below), e.g. It can be determined or confirmed by fluorescence analysis, optionally in combination with optical and/or spectroscopic methods and/or wet chemical methods. A person skilled in the art will select a preferred and appropriate determination method with knowledge of the materials used in the process.

Preferably, the particulate amorphous silicon dioxide produced or provided comprises particles having a diameter of less than 20 μm, more preferably between 0.1 μm and 5 μm, as determined by scanning electron microscopy (SEM) or laser diffraction. It includes particles having a diameter, most preferably particles having a diameter of 0.1 μm to 1.5 μm.

Determined in each case, preferably according to DIN 55992-1 (date: June 2006), type I, rotating drum principle (for example using a Heubach dust measuring device), in most cases with respect to the granules obtained has an index of dust development by the spinning method lower than that of the particulate amorphous silicon dioxide produced or provided, preferably at least 15% lower, particularly preferably at least 25% lower, most particularly preferably at least 40% lower A low process is preferred.

By "synthetically produced" particulate amorphous silicon dioxide, it is meant herein that amorphous silicon dioxide is
- be the target product of a planned chemical reaction process for the industrial synthesis of amorphous silicon dioxide, or - be a planned chemical for the industrial synthesis of a target product that is not amorphous silicon dioxide. Means it is a by-product of a reaction process.

An example of a reaction process with amorphous silicon dioxide as the target product is the flame hydrolysis of silicon tetrachloride. Amorphous SiO ₂ (“silicon dioxide”) produced by this process is also called “calcined SiO ₂ ” (“calcined silicon dioxide”) or calcined silica or fumed silica (CAS RN 112945-52-5).

An example of a reaction process in which amorphous silicon dioxide is formed as a by-product is the reduction of quartz, eg by coke, in an arc furnace to produce silicon or ferrosilicon as target products. Amorphous SiO ₂ (“silicon dioxide”) thus produced is also known as silica dust, silicon dioxide dust or SiO ₂ fume condensate or as “silica fume” or fine silica (CAS RN 69012-64-2).

A further reaction process by which amorphous silicon dioxide is synthetically produced is the _pyrolysis of _ZrSiO4 in an arc furnace to give ZrO2 and _SiO2 .

In the literature, amorphous silicon dioxide formed by flame hydrolysis of silicon tetrachloride and as a by-product during the reduction of quartz by e.g. coke in an arc furnace and by thermal decomposition of _ZrSiO4 The amorphous silicon dioxide that is formed is often described as "calcined _SiO2 "("calcined silicon dioxide") or as calcined silica. This term is also used in relation to this application.

In the context of the present invention, the calcined particulate amorphous silicon dioxide used particularly preferably includes particulate amorphous silicon dioxide identified by CAS RN 69012-64-2 and CAS RN 112945-52-5. be done. A calcined particulate amorphous silicon dioxide of this kind which is particularly preferred according to the invention is prepared in a manner known per se, in particular by reduction of quartz with carbon (e.g. coke) in an arc furnace and subsequent oxidation to silicon dioxide. (preferably in the production of ferrosilicon and silicon). Also particularly preferred are SiO ₂ prepared by thermal decomposition of ZrSiO ₄ to give ZrO ₂ from ZrSiO ₄ and SiO ₂ obtained by flame hydrolysis of silicon tetrachloride.

Particulate amorphous silicon dioxide of the type produced by reduction of quartz with carbon (eg, coke) in an arc (in the production of ferrosilicon and silicon) contains carbon. Particulate amorphous silicon dioxide of the type produced by pyrolysis of _ZrSiO4 contains zirconium oxide compounds.

Particulate synthetic amorphous silicon dioxide, which can be produced by oxidation of metallic silicon with an oxygen-containing gas, and particulate synthetic amorphous silicon dioxide, which can be produced by quenching a silicon dioxide melt, are highly free of unavoidable impurities. Very little, very pure _SiO2 .

Most preferably, the calcined particulate amorphous silicon dioxide preferably used by the present invention comprises particulate amorphous silicon dioxide of the type recognized by CAS RN 69012-64-2. It is preferably produced by reduction of quartz with carbon (e.g. coke) in an arc (e.g. in the production of ferrosilicon and silicon) or by-products of the production of ferrosilicon and silicon (silica fume). manufactured as Very particular preference is likewise given to SiO ₂ which is prepared by thermal decomposition of ZrSiO ₄ to give ZrO ₂ from ZrSiO ₄ . These types of particulate amorphous silicon dioxide are also referred to in the art as "microscopic silica".

"CAS RN" stands for CAS Registry Number and CAS Register Number (CAS=Chemical Abstract Service).

A variety of methods are suitable for combining particles of particulate amorphous silicon dioxide (and optionally further materials) in the expansion step to give grains to provide grains comprising a plurality of individual grains. . Examples of suitable methods include pelletizing, briquetting, tabletting, granulating, agglomerating, extrusion and the like.

"Handbuch der Agglomeration technik" [Handbook of Agglomeration Technology] by author Gerald Heinze (WILEY-VCH Verlag GmbH, 2000, ISBN: 3-527-29788-X) discloses processes and products from the field of agglomeration technology. ing.

EP 1 602 425 A1 describes the production of granules obtainable from silicon dioxide powders containing at least 90% amorphous SiO ₂ by granulation, in particular pelletization, with the addition of water and subsequent drying. revealing things.

A "molding material mixture" in the context of the present invention as defined above comprises a molding substrate as one of a plurality of components. As used herein, the molding substrate is preferably a refractory molding substrate. As used herein, "refractory" substances, materials and minerals, as understood by those skilled in the art, mean those that can withstand the temperature stress during casting or solidification of a ferrous melt, usually cast iron, for at least a short period of time. do. Suitable (refractory) molding substrates are natural and synthetic molding substrates such as silica sand, zircon sand or chromite sand, olivine, vermiculite, bauxite or fireclays and mixtures thereof.

The point at which the additive is added to the further components during the production of the molding compound mixture or the additive is provided to the molding compound mixture is arbitrary and freely selectable. For example, the additive may be added last to the finished molding compound mixture, or may be first pre-mixed with one or more of the above components before one or more further components are finally mixed into the molding compound mixture. can be mixed into

A solid injectable additive is understood to mean an additive for the molding material mixture in the form of fragmentary aggregates in injectable form and quantity. Individual pieces of this aggregate have a diameter of less than 0.2 mm as determined by sieving.

With respect to the above definition of the invention, an "inorganic binder" is a multi-component binder system that typically comprises additives comprising at least particulate amorphous silicon dioxide and a solution or dispersion comprising water glass. Said components are herein present as two or more spatially separated components or as a mixture. The "inorganic binder" may also contain additional particulate materials and/or additional materials in liquid or gel form as part of a mixture and/or as spatially separate components, as well as particulate amorphous silicon dioxide. .

Emissions in the form of dust can be effectively avoided or reduced to a large extent so that mixture components that are unacceptable as individual components in the casting process (e.g. classified as carcinogenic) Respirable crystalline SiO ₂ ) is also optionally used in the granules according to the invention, but is not preferred.

The term "combining" means combining the particles of particulate amorphous silicon dioxide with each other and optionally further components (see below).

The process according to the invention is suitable for the production of all moldings customary for metal castings, ie for example cores, molds and feeders. With particular advantage it is also possible to produce moldings which contain very thin wall sections. It is also particularly advantageous to have a maximum relative molding weight (weight based on the volume of a given molding of predetermined shape; in the case of cores, this is described as core weight) and a particularly high Moldings can be produced that combine strength and strength.

The present invention, in its various aspects, particularly and preferably comprises
- solid injectable additives for use as components of inorganic binders in the foundry industry,
- inorganic binders for use in the foundry industry,
- molding material mixtures containing inorganic binders for use in the foundry industry; and - moldings for use in the foundry industry for casting metal casting parts. A process (described above, preferably described above as being preferred) for manufacturing comprising the following steps:
- producing granules by the process described above, preferably described above as being preferred,
- relates to a process comprising crushing grains of particulate material to yield a solid injectable additive.

A person skilled in the art can choose from several methods for comminuting the granules of the particulate material to provide a solid injectable additive. Preferably, comminution includes grinding or crushing. However, the granules can be ground in other ways as well.

In a preferred embodiment, the comminution, preferably grinding or crushing, takes place in closed equipment so that no significant amount of dust and/or fine dust is released out of the equipment and does not contaminate the breathing air. In that case, the solid injectable additive obtained is preferably metered into a further component of the inorganic binder or of the molding material mixture, so that neither dust and/or fine dust is released.

The present invention particularly and preferably
- inorganic binders for use in the foundry industry,
- molding material mixtures containing inorganic binders for use in the foundry industry; and - moldings for use in the foundry industry for casting metal casting parts. A process (described above, preferably described above as being preferred) for manufacturing
(i) the following steps:
- producing a solid injectable additive by the process according to the invention defined above (preferably in the configuration indicated as being preferred),
- contacting the produced solid injectable additive with water glass or suspending the produced solid injectable additive in water glass, or (ii) the following steps: :
- producing granules according to the process according to the invention as defined above;
- relates to a process comprising contacting the produced granules with water glass in the presence or absence of a refractory molding substrate and simultaneously or subsequently crushing the grains of the granules.

Water glass can be produced from lithium silicate, for example, by dissolving vitreous sodium and potassium silicates in water in a hot autoclave or in a hydrothermal process. According to the invention it is possible to use water glasses containing one, two or more of the alkali metal ions mentioned above. The proportion of water glass in the molding compound mixture according to the invention is preferably in the range from 0.6 to 3% by weight.

The step of contacting the produced solid injectable additive with water glass or suspending the produced solid injectable additive in water glass, carried out in variant (i), was previously The granules produced in the method first need to be processed by comminution, preferably grinding or crushing, to obtain a solid injectable additive. Thus, solid injectable additives made from granules come into contact with or are suspended in water glass. More preferably, the step of contacting the produced solid injectable additive with water glass comprises first introducing the refractory molding substrate, then adding the solid injectable additive, and finally adding water. The glass is added and, at the same time or afterwards, all the ingredients used are blended together until they are preferably homogeneously mixed. In a less preferred embodiment, for example, the refractory molding substrate is added first, followed by the water glass, then the solid injectable additive, and simultaneously and/or thereafter all the It is also possible to change the order as the ingredients are mixed until they are homogeneously blended with each other. In a further embodiment, the solid injectable additive is blended with water glass to form a suspension, which is then added to the initial charge of the refractory molded substrate, simultaneously and subsequently used. All ingredients are mixed until they are homogeneously blended with each other.

In variant (ii), contacting the produced granules with water glass in the presence or absence of a refractory molding substrate and simultaneously or subsequently crushing the grains of the granules comprises (first crushing contacting the grains of the particulate matter with the water glass. A person skilled in the art can, depending on the circumstances of each case, achieve grain comminution by adjusting the stud conditions to the requirements of each case when contacting and blending the produced granules with water glass. can. Likewise, depending on the circumstances of each individual case, the person skilled in the art will be able to mix the produced granules with water glass by appropriately adjusting the stirring conditions in such a way that there is essentially no comminution of individual grains of the granules. can be blended with In both cases, the contacting and mixing of the produced granules with the water glass can be carried out in the presence or absence of a refractory molding substrate. If the step of contacting the produced granules with water glass is performed in the presence of a refractory molding substrate, the blending is performed at (or immediately after) the contacting and the granules are comminuted by this blend. is preferred.

In each of variants (i) and (ii) it is possible to use water glass in the form of mixtures with one or more additives, for example water glass and mixtures comprising one or more surfactants. .

Unlike the prior art, the process according to the invention does not directly use particulate amorphous SiO ₂ for the production of inorganic binders or molding material mixtures, but exclusively granules produced therefrom or solids produced therefrom. of injectable additives are used.

The effects and advantages described above in connection with the process according to the invention are achieved here to a certain extent.

Particularly and preferably, the present invention is for producing a molding material mixture for use in the foundry industry, comprising a refractory molding substrate and an inorganic binder comprising water glass and particulate amorphous silicon dioxide (see above). a process according to the invention, comprising the steps of:
- producing an inorganic binder by the process according to the invention as defined above (preferably in the configuration indicated as being preferred);
(i) simultaneously mixing the ingredients used for the production of the inorganic binder with the refractory molding substrate; and/or (ii) subsequently mixing the produced inorganic binder with the refractory molding substrate. with respect to processes including

Molding material mixtures can be prepared by mixing together the individual components used to make the inorganic binder in the presence of a refractory molding substrate to form a molding material mixture. Similarly, the molding material mixture is such that the inorganic binder is first produced by mixing the components of the inorganic binder, and the already produced inorganic binder is mixed with the refractory molding substrate to obtain the molding material mixture. can be manufactured in Depending on the requirements of the individual case, one or both variants in each case or a combination of the two variants may be preferred.

The refractory molding material preferably represents more than 80% by weight, preferably more than 90% by weight, more preferably more than 95% by weight of the total mass of the molding material mixture. The refractory molding material used according to the invention is preferably present in particulate form. It is preferably free-flowing.

によって決定される。 The refractory molded substrate preferably has an AFS grain size index in the range of 30-100. The AFS grain size index is here determined according to the VDG-Merkblatt (information sheet of the “Verein deutscher Giessereifachleute” [Society of German Foundry Experts]) October 1999, P34, point 5.2. There, the AFS grain size index is given by the formula

determined by

a plurality of individual granules each comprising combined granules and having a proportion of at least 30% by weight, preferably at least 40% by weight, more preferably at least 50% by weight based on the mass of each granule in the step of combining the particles of particulate amorphous silicon dioxide in an enlarging step to provide grains to provide a grain comprising a plurality of individual grains each comprising amorphous silicon dioxide; Preference is given to the process according to the invention (as defined above, preferably as preferred) in which the average particle size of is greater than 0.5 mm, preferably greater than 1 mm, as determined by sieving.

Thus, this preferred process according to the invention ensures that the grains have an average particle size (determined by sieving) greater than 0.5 mm, preferably greater than 1 mm, and at least 30% by weight, preferably at least Granules each containing a proportion of particulate amorphous silicon dioxide (described above) of 40% by weight, more preferably at least 50% by weight are introduced. The granules produced by this method have, in particular, an advantageous combination of the following properties: uniform composition, high bulk density, good flowability, good transportability, good meterability, low dust content, separation. Avoidance of phenomena, grinding performance, high molding weight of moldings producible with them, increased moisture stability (moisture resistance) of moldings producible with them.

Particulate amorphous silicon dioxide comprising at least 80% by weight of silicon dioxide, based on the total mass of particulate amorphous silicon dioxide, consisting wholly or partially of particulate synthetic amorphous silicon dioxide Preference is given to the process according to the invention (as described above, preferably as preferred).

Depending on the requirements of the individual case, the particulate amorphous silicon dioxide (comprising at least 80% by weight of silicon dioxide, based on the total weight of the particulate amorphous silicon dioxide) is the particulate synthetic amorphous silicon dioxide It is particularly advantageous if it consists wholly or partly of silicon. Due to the customary and preferred use of synthetic amorphous silicon dioxide, a particularly advantageous combination of properties of the moldings obtainable therefrom can be achieved with uniform and predictable quality.

The proportion of silicon dioxide in the total granulate, determined by X-ray fluorescence analysis, and in each case greater than 1 mm, preferably greater than 0.5 mm, determined by sieving and subsequent X-ray fluorescence analysis the proportion of silicon dioxide in at least 90% of the grains of the granules preferably having a grain size greater than 0.2 mm differs by no more than 30%, preferably no more than 20%, based on the proportion of silicon dioxide in the total granules Preference is given to processes according to the invention (as described above, preferably as preferred) which differ by only 10%, more preferably by 10% or less.

The proportion of silicon dioxide in the granules as a whole and in individual grains of the granules is determined according to DIN EN ISO 12677, DIN 51001 by X-ray fluorescence analysis. The (average) particle size is determined by sieving according to VDG-Merkblatt of October 1999 (i.e. information sheet of "Vereins deutscher Giessereifachleute") P27, point 4.3 specifying the use of test sieves according to DIN ISO 3310 .

The proportion of silicon dioxide in the total granules (determined by X-ray fluorescence analysis) and greater than 1 mm (determined by sieving), preferably greater than 0.5 mm (determined by sieving), more preferably the proportion of silicon dioxide (determined by X-ray fluorescence analysis) in at least 90% of the individual grains of granules having a particle size greater than 0.2 mm (determined by sieving) and differ by no more than 30%, preferably no more than 20%, more preferably no more than 10% (relative to the proportion of silicon dioxide), that granules of this (minimum) size in their composition are It is meant to be a good representative of the total composition of the granules and therefore of the total material used. For each of the stated diameters (1 mm, 0.5 mm, 0.2 mm), depending on the individual case, any of the specified maximum differences (30%, 20%, 10%) may be relevant and advantageous. . Therefore, depending on the requirements of the individual case, any combination of diameters and maximum differences that can be obtained is preferred.

In the expanding step, the particles of particulate amorphous silicon dioxide are
- a liquid comprising a gel-like substance, preferably a liquid wetting agent and/or suspension medium, preferably water,
- preferably oxides of aluminum, preferably alpha-phase aluminum oxide, bauxite, oxides of zirconium, preferably zirconium(IV) oxide, aluminum/silicon mixed oxides, zinc oxide, barium sulfate, phosphorus compounds, sheet silicates, graphite , carbon black, glass beads, oxides of magnesium, borosilicates, ceramic hollow beads, boron oxide compounds, preferably powdered boron oxide compounds and mixtures thereof, preferably particulate inorganic material,
- water-soluble materials,
- an alkali metal hydroxide,
- surfactants,
- a film former,
- rheological additives (thickeners, suspension aids),
- Hydrophobizing agents, preferably mixed with one, two or more further materials independently selected from the group consisting of organosilicon compounds, silanes, silicones and siloxanes, waxes, paraffins, metal soaps, and - carbohydrates. Preference is given to the process according to the invention (as mentioned above, preferably as preferred) in which and/or contacted.

The particulate amorphous silicon dioxide is preferably mixed and/or contacted with one, two or more additional materials (which are not themselves particulate amorphous silicon dioxide) in the expansion step. The one, two or more additional materials with which the particulate amorphous silicon dioxide is mixed and/or contacted in the expansion step are independently selected from the above list, i.e. the selection of the first material is It has no effect on any subsequent material selection.

Preferably, the surfactant is oleyl sulfate, stearyl sulfate, palmityl sulfate, myristyl sulfate, lauryl sulfate, decyl sulfate, octyl sulfate, 2-ethylhexyl sulfate, 2-ethyloctyl sulfate, 2-ethyl decyl sulfate, palmitole 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-(1,2 ethanediyl)-phenol hydroxyphosphate, poly-(1,2-ethanediyl)-stearyl phosphate, poly -(1,2-ethanediyl)-oleyl phosphate, polycarboxylate ethers in water (e.g. Melpers 0030, BASF), modified polyacrylates (e.g. Melpers VP 4547/240L, BASF) in water, 2-ethylhexyl sulfate in water phate (e.g. Texapon EHS, Cognis), polyglucosides (e.g. Glukopon 225 DK, Cognis) in water, sodium octyl sulfate (e.g. Texapon 842, Lakeland) in water, modified carboxylate ethers (e.g. Castament ES 60, solid , BASF).

Preferably, the film former is independently selected from or comprises the group consisting of polyvinyl alcohol and acrylic acid.

Preferably, rheological additives (thickeners, suspension aids) are
- swelling clays, preferably sodium bentonite or attapulgite/palygorskite,
- swellable polymers, preferably cellulose derivatives, in particular carboxymethyl, methyl, ethyl, hydroxyethyl and hydroxypropylcellulose, independently from the group consisting of plant mucilage, polyvinylpyrrolidone, pectin, gelatin, agar, polypeptides and/or alginates; are selected by or include them.

Preferably, the hydrophobizing agent is preferably independently selected from the group consisting of organosilicon compounds, silanes, silanols, preferably trimethylsilanol, silicones and siloxanes, preferably polydimethylsiloxanes, waxes, paraffins, metal soaps. or contain them.

The above materials are preferred in connection with the present invention. Additional materials may be used depending on the needs of the individual case.

Thus, the materials described above can be used in the process according to the invention without the need for additional metering steps in the casting or additional reservoirs. Preferably, such ingredients, including those liquid ingredients that do not exhibit long-term stability in water glass (including those in gel form), are removed by incorporating them into the granules formed in the expansion step. It can also be incorporated into molding compound mixtures produced according to the invention without the need for an additional metering step.

As used herein, the term "carbohydrate" is understood to mean aldoses (pyrohydroxyaldehydes) and ketoses (polyhydroxyketones) and higher molecular weight compounds convertible to such compounds by hydrolysis. be. Carbohydrates used in connection with the present invention are oligomers and polymers with a chain length of n>2. The invention also relates to the grains of the granulate resulting from the expansion step, preferably having a particle size larger than 1 mm, preferably larger than 0.5 mm, more preferably larger than 0.2 mm, determined by sieving in each case. at least 90% of the grains of the granules having
(i) particulate amorphous silicon dioxide and one, two, three or more or all of the further solid materials present in the expansion step, and/or (ii) particulate amorphous silicon dioxide ,
- preferably oxides of aluminum, preferably alpha-phase aluminum oxide, bauxite, oxides of zirconium, preferably zirconium(IV) oxide, aluminum/silicon mixed oxides, zinc oxide, barium sulphate, phosphorus compounds, sheet silicates, graphite , carbon black, glass beads, oxides of magnesium, borosilicates, ceramic hollow beads, boron oxide compounds, preferably powdered boron oxide compounds and mixtures thereof, preferably particulate inorganic material,
- water-soluble materials,
- an alkali metal hydroxide,
- surfactants,
- a film former,
- rheological additives (thickeners, suspension aids),
- a hydrophobizing agent, preferably one, two or more further materials independently selected from the group consisting of organosilicon compounds, silanes, silicones and siloxanes, waxes, paraffins, metal soaps, and carbohydrates. It relates to the process according to the invention (as described above, preferably as preferred), comprising:

The proportion/presence of silicon dioxide in the individual grains of the granules is determined according to DIN EN ISO 12677, DIN 51001 by X-ray fluorescence analysis. The particle size is determined by sieving according to VDG-Merkblatt of October 1999 (ie information sheet of “Vereins deutscher Giessereifachleute”) P27, point 4.3, specifying the use of test sieves according to DIN ISO 3310. The presence of one, two, three or more or all further solid materials present in the grains of the granulate during the expansion step (especially after sieving by VDG-Merkblatt P 27, see above) can be determined by e.g. DIN It can likewise be determined or confirmed by X-ray fluorescence analysis according to EN ISO 12677, DIN 51001, optionally in combination with optical and/or spectroscopic methods and/and wet chemical methods. The person skilled in the art selects a preferred and suitable determination method with knowledge of the materials used in the process.

At least 90% of the grains of the granules, preferably the grains of the granules having a particle size (each determined by sieving) greater than 0.2 mm, preferably greater than 0.5 mm, more preferably greater than 1 mm, are particles including amorphous silicon dioxide and one, two, three or more or all of the other solid materials present in the expanding step includes one, two, or all of the other solid materials present in the expanding step; three or more or all of which are part of the granules obtained, preferably at least 90 of the grains of the granules (having a particle size greater than 0.2 mm, preferably greater than 0.5 mm, more preferably greater than 1 mm) means that it is part of %. Therefore, one, two, three or more or all of the other solid materials present in the expansion step are preferably part of the granules, more preferably they are uniformly distributed in the granules. , they are present in at least 90% of the grains of the granulate having a particle size (each determined by sieving) greater than 1 mm, preferably greater than 0.5 mm, more preferably greater than 0.2 mm.

In addition to the particulate amorphous silicon dioxide, one, two, three or more or all of the other materials present in the expansion step are selected independently of each other. Each of the possible resulting combinations leads, depending on the requirements of the individual case, to particularly advantageous properties or combinations of properties in the shaped articles producible therefrom.

producing particulate amorphous silicon dioxide comprising at least 80% by weight of silicon dioxide, based on the total mass of particulate amorphous silicon dioxide;
- comprising mixing two or more different types of particulate amorphous silicon dioxide, the two or more types preferably having their particle size distribution determined by laser scattering, e.g. Preference is given to processes according to the invention (described above, preferably as preferred), which differ by the median of their particle size distribution and/or their chemical composition.

As used herein, both types of particulate amorphous silicon dioxide can be selected such that they are chemically distinct and have different particle size distributions. Alternatively, both types can be selected such that they have the same chemical composition but different particle size distributions only. Additionally, both types of particulate amorphous silicon dioxide can be selected such that although they are chemically different, they have the same particle size distribution.

The median value of the particle size distribution is the value at which one-half of the tested particle population has a size smaller than this value and the other half of the tested particle population has a size larger than this value. understood as being. Preferably, this value is determined as described in Example 1 below for commercially available materials.

"Determined by light scattering" means that the sample of particulate material being tested (herein and below) is, if desired, as previously as in the method of Example 1 (see below). It is meant that the particle size distribution of the treated and so pretreated material is determined by laser scattering as in Example 1 (see below).

The present invention
(i)—the first type of particulate amorphous silicon dioxide has a particle size distribution with a median value in the range of 0.1 to 0.4 μm as determined by laser scattering;
- a further type of particulate amorphous silicon dioxide has a particle size distribution with a median in the range of 0.7-1.5 μm, determined by laser scattering, and/or (ii) a different type of one, two, three or more or all of the particulate amorphous silicon dioxide
- Particulate synthetic amorphous silicon dioxide, preferably producible by reducing quartz in an electric arc furnace, comprising a total mass of particulate synthetic amorphous silicon dioxide and at least carbon as a secondary component Particulate synthetic amorphous silicon dioxide containing silicon dioxide in a proportion of at least 80% by weight based on
- particulate synthetic amorphous silicon dioxide containing zirconium oxide as a secondary component and preferably producible by pyrolysis of _ZrSiO4 ,
- particulate synthetic amorphous silicon dioxide, producible by oxidation of metallic silicon with an oxygen-containing gas,
- selected from or independently selected from the group (of chemically distinct materials) consisting of particulate synthetic amorphous silicon dioxide producible by quenching a silicon dioxide melt, , preferably mentioned above as being preferred) also relates to the process according to the invention.

Preferably, at least 90% of the grains of the granules having a particle size of more than 0.2 mm, preferably more than 0.5 mm, more preferably more than 1 mm, determined by sieving in each case (suitable sample After treatment, in particular after screening with VDG-Merkblatt P 27, see below)) by X-ray fluorescence analysis, for example according to DIN EN ISO 12677, DIN 51001, optionally optical and/or spectroscopic methods and/or wet chemical methods Preference is given to a process according to the invention (described above, preferably described above as being preferred) which comprises both or at least two of the different types of particulate amorphous silicon dioxide determined or identified in combination with . The person skilled in the art selects a preferred and suitable determination method with knowledge of the materials used in the process.

the enlargement step
- granulation,
Preference is given to the process according to the invention (as described above, preferably as preferred) comprising one or more means independently selected from the group consisting of - extrusion and - agglomeration, preferably pressure agglomeration.

Further suitable methods for carrying out the expansion step, ie for example pelletizing, briquetting, tableting etc. are known from the prior art and can alternatively or additionally be used according to the invention. Reference is made to the above description.

The present invention relates to the production of injectable additives for use as a component of inorganic binders in the foundry industry, comprising (preferably synthetic) particulate amorphous silicon dioxide, determined by screening, 0. Granules having an average particle size greater than 2 mm,
(a) one, two or more additional materials,
- preferably oxides of aluminum, preferably alpha-phase aluminum oxide, bauxite, oxides of zirconium, preferably zirconium(IV) oxide, aluminum/silicon mixed oxides, zinc oxide, barium sulphate, phosphorus compounds, sheet silicates, graphite , carbon black, glass beads, oxides of magnesium, borosilicates, ceramic hollow beads, boron oxide compounds, preferably powdered boron oxide compounds and mixtures thereof, preferably particulate inorganic material,
- water-soluble materials,
- an alkali metal hydroxide,
- surfactants,
- a film former,
- hydrophobizing agents, preferably adding one, two or more further materials independently selected from the group consisting of organosilicon compounds, silanes, silicones and siloxanes, waxes, paraffins, metal soaps, and - carbohydrates. at least 90% of the grains of the granules having a particle size larger than 0.2 mm, preferably larger than 0.5 mm, more preferably larger than 1 mm, determined in each case by sieving, are particulate comprising amorphous silicon dioxide and one, two or more of said further materials, and/or (b) the particulate amorphous silicon dioxide being the total mass of particulate amorphous silicon dioxide comprising a proportion of at least 80% by weight of silicon dioxide, preferably consisting entirely or partially of particulate synthetic amorphous silicon dioxide, and/or the proportion of silicon dioxide in the total mass and in at least 90% of the grains of the granules with a particle size greater than 1 mm, determined in each case by sieving and subsequent X-ray fluorescence analysis, differ by 30% or less, preferably differ by 20% or less, more preferably differ by 10% or less, based on the proportion of silicon dioxide in the total granule, and/or (d) in the granule, particulate amorphous The amorphous silicon dioxide comprises two or more different types of particulate amorphous silicon dioxide, two or more types preferably (especially after screening according to VDG-Merkblatt P 27, see above) DIN EN by X-ray fluorescence analysis according to ISO 12677, DIN 51001 (optionally in combination with optical and/or spectroscopic methods and/or wet chemical methods), the skilled person, with his knowledge of the materials used in the process depending on their chemical composition to be determined or confirmed, preferably one, two, three or more or all of the different types of particulate amorphous silicon dioxide,
- Particulate synthetic amorphous silicon dioxide, preferably producible by reduction of quartz in an electric arc furnace, comprising a total mass of particulate synthetic amorphous silicon dioxide and at least carbon as a secondary component Particulate synthetic amorphous silicon dioxide containing silicon dioxide in a proportion of at least 80% by weight based on
- particulate synthetic amorphous silicon dioxide containing zirconium oxide as a secondary component and preferably producible by pyrolysis of _ZrSiO4 ,
- particulate synthetic amorphous silicon dioxide, producible by oxidation of metallic silicon with an oxygen-containing gas,
- selected from or independently selected from the group consisting of particulate synthetic amorphous silicon dioxide producible by quenching a silicon dioxide melt; It also relates to granules, preferably producible by the processes described above as being preferred.

Granules defined in this way (i.e. specific whole granules, see above) have in particular an advantageous combination of the following properties: uniform composition, high bulk density, low dust content, good flow. good transportability, good meterability, low dust content, avoidance of segregation phenomena, grinding performance, high molding weights of the moldings which can be produced therefrom, moisture stability of the moldings which can be produced therefrom ( moisture resistance).

Configurations (a) and (e) are of particular economic importance and are therefore preferred in many cases.

The present invention also relates to kits containing particulates (as described above, preferably as preferred) as spatially separate components.

The present invention provides an inorganic binder (described above, preferably described above as being preferred), more preferably as components in mutually spatially discrete arrangements,
- a kit for the production of a binder comprising and/or consisting of an inorganic multi-component binder system comprising at least granules (as described above, preferably as preferred) and - a solution or dispersion comprising water glass Also related to

The kit according to the invention is particularly suitable for carrying out the process according to the invention with which the subsequent product of granulate (binder; molding material mixture; molding) is produced.

The effects and advantages described above in connection with the process according to the invention and the granules according to the invention are achieved when the kit according to the invention is used.

The present invention provides an apparatus for carrying out the process according to the invention (as described above, preferably as preferred), comprising:
- a storage container containing particulate amorphous silicon dioxide, the particulate amorphous silicon dioxide comprising a proportion of at least 80% by weight of silicon dioxide, based on the total weight of the particulate amorphous silicon dioxide;
- a mixing or contacting device for mixing or contacting particulate amorphous silicon dioxide with one, two or more further materials,
- also relates to an apparatus comprising a device for granulating, extruding and/or agglomerating particulate amorphous silicon dioxide mixed or contacted with one, two or more further materials.

The apparatus according to the invention is particularly suitable for carrying out the process according to the invention and for producing granules according to the invention.

The effects and advantages described above in connection with the process according to the invention and the granules according to the invention can be achieved when the device according to the invention is used and can be established according to individual case requirements.

- a device for transferring particulate amorphous silicon dioxide from a storage container to a mixing or contacting device,
- one or more reservoirs containing a liquid, preferably a liquid wetting agent and/or a suspending medium, preferably water,
- preferably oxides of aluminum, preferably alpha-phase aluminum oxide, bauxite, oxides of zirconium, preferably zirconium(IV) oxide, aluminum/silicon mixed oxides, zinc oxide, barium sulfate, phosphorus compounds, sheet silicates, graphite , carbon black, glass beads, oxides of magnesium, borosilicates, ceramic hollow beads, boron oxide compounds, preferably powdered boron oxide compounds and mixtures thereof, preferably particulate one or more storage containers containing inorganic material;
- one or more reservoirs containing water-soluble materials,
- one or more reservoirs containing one or more surfactants,
- one or more reservoirs containing one or more hydrophobizing agents,
- according to the invention (as described above, preferably as preferred), additionally comprising one or more device elements selected from the group consisting of one or more reservoirs containing one or more carbohydrates A device is preferred.

Depending on the requirements of the individual case, preferred apparatuses (plants) are particularly advantageously suitable for carrying out the process according to the invention and for producing granules according to the invention.

Preference is given to an apparatus according to the invention (as described above, preferably as preferred) which additionally comprises a device for dispensing or transporting the produced granules.

The present invention also extends to the corresponding use (as defined above, preferably as preferred) of (preferably synthetic) particulate amorphous silicon dioxide for the production of granules or as a component of granules. related.

Molding material mixtures produced therefrom by the use of particulate amorphous silicon dioxide according to the invention for the production of granules or as a component of granules, depending on the particle size distribution of the particulate amorphous silicon dioxide moldings with a specific, preferably particularly high relative molding weight (in the case of the core: core weight) are produced. Molding material mixtures produced therefrom by the use of particulate amorphous silicon dioxide according to the invention for the production of granules or as a component of granules, depending on the particle size distribution of the particulate amorphous silicon dioxide Moldings are produced from this which have a particular, preferably particularly high, moisture stability.

The present invention relates to the production of solid injectable additives having a homogenized grain composition for use as a component of mineral binders in the foundry industry (described above, preferably according to the invention or preferred and the use of particulates).

Preferred embodiments of the present invention are shown below.

1. A process for producing granules for the production of an injectable additive for use as a component of an inorganic binder in the foundry industry, comprising the following steps for producing the granules:
- Particulate amorphous silicon dioxide comprising at least 80% by weight, preferably at least 90% by weight of silicon dioxide, based on the total weight of the particulate amorphous silicon dioxide producing or providing silicon dioxide;
- a plurality of individual grains, each comprising combined grains and having a proportion of at least 30% by weight, preferably at least 40% by weight, more preferably at least 50% by weight, based on the mass of each grain; combining the particles of particulate amorphous silicon dioxide in an enlarging step to give a grain to provide a grain comprising a plurality of individual grains each comprising amorphous silicon dioxide, wherein the grain average The particle size is greater than 0.2 mm as determined by sieving, preferably the particulate amorphous silicon dioxide produced or provided is determined by scanning electron microscopy (SEM) or laser diffraction. A process comprising particles having a diameter of less than 20 μm, more preferably particles having a diameter between 0.1 μm and 5 μm, most preferably particles having a diameter between 0.1 μm and 1.5 μm.

The product of this process is the granules described above.

2. A process for producing a solid injectable additive for use as a component of an inorganic binder in the foundry industry, comprising the following (and further) steps for producing the solid injectable additive:
- Particulate amorphous silicon dioxide comprising at least 80% by weight, preferably at least 90% by weight of silicon dioxide, based on the total weight of the particulate amorphous silicon dioxide producing or providing silicon dioxide;
- a plurality of individual grains, each comprising combined grains and having a proportion of at least 30% by weight, preferably at least 40% by weight, more preferably at least 50% by weight, based on the mass of each grain; combining the particles of particulate amorphous silicon dioxide in an enlarging step to give a grain to provide a grain comprising a plurality of individual grains each comprising amorphous silicon dioxide, wherein the grain average The particle size is greater than 0.2 mm as determined by sieving, preferably the particulate amorphous silicon dioxide produced or provided is determined by scanning electron microscopy (SEM) or laser diffraction. A process comprising particles having a diameter of less than 20 μm, more preferably particles having a diameter between 0.1 μm and 5 μm, most preferably particles having a diameter between 0.1 μm and 1.5 μm.

3. A process for producing an inorganic binder for use in the foundry industry comprising the following (and further) steps for producing the inorganic binder:
- Particulate amorphous silicon dioxide comprising at least 80% by weight, preferably at least 90% by weight of silicon dioxide, based on the total weight of the particulate amorphous silicon dioxide producing or providing silicon dioxide;
- a plurality of individual grains, each comprising combined grains and having a proportion of at least 30% by weight, preferably at least 40% by weight, more preferably at least 50% by weight, based on the mass of each grain; combining the particles of particulate amorphous silicon dioxide in an enlarging step to give a grain to provide a grain comprising a plurality of individual grains each comprising amorphous silicon dioxide, wherein the grain average The particle size is greater than 0.2 mm as determined by sieving, preferably the particulate amorphous silicon dioxide produced or provided is determined by scanning electron microscopy (SEM) or laser diffraction. A process comprising particles having a diameter of less than 20 μm, more preferably particles having a diameter between 0.1 μm and 5 μm, most preferably particles having a diameter between 0.1 μm and 1.5 μm.

4. A process for producing a molding material mixture containing an inorganic binder for use in the foundry industry, comprising the following (and further) steps for producing the molding material mixture:
- Particulate amorphous silicon dioxide comprising at least 80% by weight, preferably at least 90% by weight of silicon dioxide, based on the total weight of the particulate amorphous silicon dioxide producing or providing silicon dioxide;
- a plurality of individual grains, each comprising combined grains and having a proportion of at least 30% by weight, preferably at least 40% by weight, more preferably at least 50% by weight, based on the mass of each grain; combining the particles of particulate amorphous silicon dioxide in an enlarging step to give a grain to provide a grain comprising a plurality of individual grains each comprising amorphous silicon dioxide, wherein the grain average The particle size is greater than 0.2 mm as determined by sieving, preferably the particulate amorphous silicon dioxide produced or provided is determined by scanning electron microscopy (SEM) or laser diffraction. A process comprising particles having a diameter of less than 20 μm, more preferably particles having a diameter between 0.1 μm and 5 μm, most preferably particles having a diameter between 0.1 μm and 1.5 μm.

5. A method for producing a molding for use in casting metal casting parts in the foundry industry comprising the following (and further) steps for producing the molding:
- Particulate amorphous silicon dioxide comprising at least 80% by weight, preferably at least 90% by weight of silicon dioxide, based on the total weight of the particulate amorphous silicon dioxide producing or providing silicon dioxide;
- a plurality of individual grains, each comprising combined grains and having a proportion of at least 30% by weight, preferably at least 40% by weight, more preferably at least 50% by weight, based on the mass of each grain; combining the particles of particulate amorphous silicon dioxide in an enlarging step to give a grain to provide a grain comprising a plurality of individual grains each comprising amorphous silicon dioxide, wherein the grain average The particle size is greater than 0.2 mm as determined by sieving, preferably the particulate amorphous silicon dioxide produced or provided is determined by scanning electron microscopy (SEM) or laser diffraction. A process comprising particles having a diameter of less than 20 μm, more preferably particles having a diameter between 0.1 μm and 5 μm, most preferably particles having a diameter between 0.1 μm and 1.5 μm.

6. A process according to aspect 2 for producing a solid injectable additive for use as a component of an inorganic binder in the foundry industry, comprising the steps of:
- producing granules by the process according to aspect 1;
- A process comprising crushing the granules to yield a solid injectable additive.

7. A process according to embodiment 3 for producing an inorganic binder for use in the foundry industry, comprising the steps of:
- producing granules by the process according to aspect 1;
- A process comprising crushing the granules to yield a solid injectable additive.

8. A process according to aspect 4 for producing a molding material mixture comprising an inorganic binder for use in the foundry industry, comprising the steps of:
- producing granules by the process according to aspect 1;
- A process comprising crushing the granules to yield a solid injectable additive.

9. A process according to aspect 5 for producing moldings for use in casting metal casting parts in the foundry industry, comprising the steps of:
- producing granules by the process according to aspect 1;
- A process comprising crushing the granules to yield a solid injectable additive.

10. 8. A process according to any of the above aspects 3 and 7 for producing an inorganic binder for use in the foundry industry, comprising the steps of:
- producing a solid injectable additive by a process according to any of aspects 2 and 6;
- A process comprising contacting the produced solid injectable additive with water glass or suspending the produced solid injectable additive in water glass.

11. 11. A process according to any of the above aspects 3, 7 and 10 for producing an inorganic binder for use in the foundry industry, comprising the steps of:
- producing granules by a process according to any of aspects 1 to 9;
- A process comprising contacting the produced granules with water glass in the presence or absence of a refractory molding substrate and simultaneously or subsequently crushing the granules.

12. 9. A process according to any of aspects 4 and 8 above for producing a molding material mixture comprising an inorganic binder for use in the foundry industry, comprising the steps of:
- preparing a solid injectable additive by a process according to any of aspects 2, 6 and 10;
- A process comprising contacting the produced solid injectable additive with water glass or suspending the produced solid injectable additive in water glass.

13. 13. A process according to any of the above aspects 4, 8 and 12 for producing a molding material mixture comprising an inorganic binder for use in the foundry industry, comprising the steps of:
- producing granules by a process according to any of aspects 1-9 or 11;
- A process comprising contacting the produced granules with water glass in the presence or absence of a refractory molding substrate and simultaneously or subsequently crushing the granules.

14. 10. A process according to any of the above aspects 5 and 9 for producing moldings for use in casting metal casting parts in the foundry industry, comprising the steps of:
- preparing a solid injectable additive by a process according to any of aspects 2, 6 and 10;
- A process comprising contacting the produced solid injectable additive with water glass or suspending the produced solid injectable additive in water glass.

15. 15. A process according to any of the above aspects 5, 9 and 14 for producing moldings for use in casting metal casting parts in the foundry industry, comprising the steps of:
- producing granules by a process according to any of aspects 1-9, 11 and 13;
- A process comprising contacting the produced granules with water glass in the presence or absence of a refractory molding substrate and simultaneously or subsequently crushing the granules.

16. Aspects 4, 8, 12 and 13 above for producing a molding material mixture comprising a refractory molding substrate and an inorganic binder comprising water glass and particulate amorphous silicon dioxide for use in the foundry industry. A process by any of the following steps:
- producing an inorganic binder according to any of aspects 3, 7, 10 and 11;
- at the same time mixing the components used for the production of the inorganic binder with the refractory molding substrate.

17. Embodiments 4, 8, 12, 13 and 16 above for producing a molding material mixture comprising a refractory molding substrate and an inorganic binder comprising water glass and particulate amorphous silica for use in the foundry industry. A process by any of the following steps:
- producing an inorganic binder according to any of aspects 3, 7, 10, 11, 16;
- simultaneously mixing the ingredients used for the production of the inorganic binder with the refractory molding substrate; and - subsequently mixing the produced inorganic binder with the refractory molding substrate.

18. Embodiments 4, 8, 12, 13, 16 and for producing a molding material mixture comprising a refractory molding substrate and an inorganic binder comprising water glass and particulate amorphous silica for use in the foundry industry 17, comprising the steps of:
- producing an inorganic binder according to any of aspects 3, 7, 10, 11, 16, 17;
- subsequently mixing the inorganic binder produced with a refractory molding substrate.

19. A process according to any of aspects 1-5, comprising a plurality of individual grains, each comprising combined grains, and comprising at least 30% by weight, preferably at least 40% by weight, based on the mass of each grain combining the particles of particulate amorphous silicon dioxide in an expansion step to provide a granule comprising a plurality of individual grains each comprising a proportion of at least 50% by weight of particulate amorphous silicon dioxide, A process wherein, in the step of providing granules, the average particle size of the granules is greater than 0.5 mm, preferably greater than 1 mm as determined by sieving.

20. The particulate amorphous silicon dioxide comprising at least 80% by weight of silicon dioxide, based on the total weight of the particulate amorphous silicon dioxide, is the particulate synthetic amorphous A process according to any of the above embodiments, consisting entirely of silicon dioxide.

21. The particulate amorphous silicon dioxide comprising at least 80% by weight of silicon dioxide, based on the total weight of the particulate amorphous silicon dioxide, is the particulate synthetic amorphous A process according to any of the above embodiments, consisting partially of silicon dioxide.

22. The proportion of silicon dioxide in the total granules as determined by X-ray fluorescence analysis and the dioxide in at least 90% of the grains of the granules having a particle size greater than 1 mm as determined by sieving and subsequent X-ray fluorescence analysis A process according to any of the preceding aspects, wherein the percentage of silicon differs by no more than 30% based on the percentage of silicon dioxide in the total granulate.

23. The proportion of silicon dioxide in the total granules as determined by X-ray fluorescence analysis and the dioxide in at least 90% of the grains of the granules having a particle size greater than 1 mm as determined by sieving and subsequent X-ray fluorescence analysis A process according to any of the preceding aspects, wherein the percentage of silicon differs by no more than 20% based on the percentage of silicon dioxide in the total granulate.

24. The proportion of silicon dioxide in the total granules as determined by X-ray fluorescence analysis and the dioxide in at least 90% of the grains of the granules having a particle size greater than 1 mm as determined by sieving and subsequent X-ray fluorescence analysis A process according to any of the preceding embodiments, wherein the percentage of silicon differs by no more than 10% based on the percentage of silicon dioxide in the total granulate.

25. The proportion of silicon dioxide in the total granules determined by X-ray fluorescence analysis and at least 90% of the grains of the granules having a particle size greater than 0.5 mm as determined by sieving and subsequent X-ray fluorescence analysis differs by no more than 30% based on the percentage of silicon dioxide in the total particulate matter.

26. The proportion of silicon dioxide in the total granules determined by X-ray fluorescence analysis and at least 90% of the grains of the granules having a particle size greater than 0.5 mm as determined by sieving and subsequent X-ray fluorescence analysis A process according to any of the preceding aspects, wherein the proportion of silicon dioxide in the is different by no more than 20% based on the proportion of silicon dioxide in the total particulate matter.

27. The proportion of silicon dioxide in the total granules determined by X-ray fluorescence analysis and at least 90% of the grains of the granules having a particle size greater than 0.5 mm as determined by sieving and subsequent X-ray fluorescence analysis is different by no more than 10% based on the percentage of silicon dioxide in the total particulate matter.

28. The proportion of silicon dioxide in the total granules determined by X-ray fluorescence analysis and at least 90% of the grains of the granules having a particle size greater than 0.2 mm as determined by screening and subsequent X-ray fluorescence analysis differs by no more than 30% based on the percentage of silicon dioxide in the total particulate matter.

29. The proportion of silicon dioxide in the total granules determined by X-ray fluorescence analysis and at least 90% of the grains of the granules having a particle size greater than 0.2 mm as determined by screening and subsequent X-ray fluorescence analysis A process according to any of the preceding aspects, wherein the proportion of silicon dioxide in the is different by no more than 20% based on the proportion of silicon dioxide in the total particulate matter.

30. The proportion of silicon dioxide in the total granules determined by X-ray fluorescence analysis and at least 90% of the grains of the granules having a particle size greater than 0.2 mm as determined by screening and subsequent X-ray fluorescence analysis is different by no more than 10% based on the percentage of silicon dioxide in the total particulate matter.

31. In the expansion step, the particles of particulate amorphous silicon dioxide are
- a liquid, preferably a liquid wetting agent and/or suspension medium, preferably water,
- preferably oxides of aluminum, preferably alpha-phase aluminum oxide, bauxite, oxides of zirconium, preferably zirconium(IV) oxide, aluminum/silicon mixed oxides, zinc oxide, barium sulfate, phosphorus compounds, sheet silicates, graphite , carbon black, glass beads, oxides of magnesium, borosilicates, ceramic hollow beads, boron oxide compounds, preferably powdered boron oxide compounds and mixtures thereof, preferably particulate inorganic material,
- water-soluble materials,
- an alkali metal hydroxide,
- surfactants,
- a film former,
- Hydrophobizing agents, preferably mixed with one, two or more further materials independently selected from the group consisting of organosilicon compounds, silanes, silicones and siloxanes, waxes, paraffins, metal soaps, and - carbohydrates. and/or contacted.

32. grains of granulate resulting from the expansion step, preferably grains of granulate having a particle size determined by sieving in each case greater than 1 mm, preferably greater than 0.5 mm, more preferably greater than 0.2 mm at least 90% of
(i) particulate amorphous silicon dioxide and one, two, three or more or all of the additional solid materials present in the expansion step; and (ii) particulate amorphous silicon dioxide;
- preferably oxides of aluminum, preferably alpha-phase aluminum oxide, bauxite, oxides of zirconium, preferably zirconium(IV) oxide, aluminum/silicon mixed oxides, zinc oxide, barium sulphate, phosphorus compounds, sheet silicates, graphite , carbon black, glass beads, oxides of magnesium, borosilicates, ceramic hollow beads, boron oxide compounds, preferably powdered boron oxide compounds and mixtures thereof, preferably particulate inorganic material,
- water-soluble materials,
- an alkali metal hydroxide,
- surfactants,
- a film former,
- a hydrophobizing agent, preferably one, two or more further materials independently selected from the group consisting of organosilicon compounds, silanes, silicones and siloxanes, waxes, paraffins, metal soaps, and carbohydrates. 32. A process according to aspect 31, comprising:

33. grains of granulate resulting from the expansion step, preferably grains of granulate having a particle size determined by sieving in each case greater than 1 mm, preferably greater than 0.5 mm, more preferably greater than 0.2 mm at least 90% of
- A process according to aspect 31, comprising particulate amorphous silicon dioxide and one, two, three or more or all of the other solid materials present in the expansion step.

34. grains of granulate resulting from the expansion step, preferably grains of granulate having a particle size of more than 1 mm, preferably more than 0.5 mm, more preferably more than 0.2 mm, determined in each case by sieving at least 90% of
- particulate amorphous silicon dioxide;
- preferably oxides of aluminum, preferably alpha-phase aluminum oxide, bauxite, oxides of zirconium, preferably zirconium(IV) oxide, aluminum/silicon mixed oxides, zinc oxide, barium sulfate, phosphorus compounds, sheet silicates, graphite , carbon black, glass beads, oxides of magnesium, borosilicates, ceramic hollow beads, boron oxide compounds, preferably powdered boron oxide compounds and mixtures thereof, preferably particulate inorganic material,
- water-soluble materials,
- an alkali metal hydroxide,
- surfactants,
- a film former,
- a hydrophobizing agent, preferably one, two or more further materials independently selected from the group consisting of organosilicon compounds, silanes, silicones and siloxanes, waxes, paraffins, metal soaps, and carbohydrates. 32. A process according to aspect 31, comprising:

35. Producing particulate amorphous silicon dioxide, the particulate amorphous silicon dioxide comprising a proportion of at least 80% by weight of silicon dioxide, based on the total weight of the particulate amorphous silicon dioxide,
- according to any of the above aspects, comprising mixing two or more different types of particulate amorphous silicon dioxide, the two or more types differing by their particle size distribution and/or their chemical composition. process.

36. - A process according to aspect 35, wherein one type of particulate amorphous silicon dioxide has a particle size distribution with a median value in the range of 0.1 to 0.4 μm as determined by laser scattering.

37. - A process according to aspect 35, wherein one type of particulate amorphous silicon dioxide has a particle size distribution with a median value in the range of 0.7 to 1.5 μm as determined by laser scattering.

38. one, two, three or more or all of the different types of particulate amorphous silicon dioxide are
- Particulate synthetic amorphous silicon dioxide, preferably producible by reducing quartz in an electric arc furnace, comprising a total mass of particulate synthetic amorphous silicon dioxide and at least carbon as a secondary component Particulate synthetic amorphous silicon dioxide containing silicon dioxide in a proportion of at least 80% by weight based on
- particulate synthetic amorphous silicon dioxide containing zirconium oxide as a secondary component and preferably producible by pyrolysis of _ZrSiO4 ,
- particulate synthetic amorphous silicon dioxide, producible by oxidation of metallic silicon with an oxygen-containing gas,
- a process according to aspect 35, selected from or independently selected from the group consisting of particulate synthetic amorphous silicon dioxide producible by quenching a silicon dioxide melt.

39. - the first type of particulate amorphous silicon dioxide has a particle size distribution with a median value in the range 0.1 to 0.4 μm, determined by laser scattering;
- A process according to aspect 35, wherein the further type of particulate amorphous silicon dioxide has a particle size distribution with a median value in the range 0.7 to 1.5 μm as determined by laser scattering.

40. - the first type of particulate amorphous silicon dioxide has a particle size distribution with a median value in the range 0.1 to 0.4 μm, determined by laser scattering;
- one, two, three or more or all of the different types of particulate amorphous silicon dioxide are
- Particulate synthetic amorphous silicon dioxide, preferably producible by reducing quartz in an electric arc furnace, comprising a total mass of particulate synthetic amorphous silicon dioxide and at least carbon as a secondary component Particulate synthetic amorphous silicon dioxide containing silicon dioxide in a proportion of at least 80% by weight based on
- particulate synthetic amorphous silicon dioxide containing zirconium oxide as a secondary component and preferably producible by pyrolysis of _ZrSiO4 ,
- particulate synthetic amorphous silicon dioxide, producible by oxidation of metallic silicon with an oxygen-containing gas,
- a process according to aspect 35, selected from or independently selected from the group consisting of particulate synthetic amorphous silicon dioxide producible by quenching a silicon dioxide melt.

41. - the first type of particulate amorphous silicon dioxide has a particle size distribution with a median value in the range 0.1 to 0.4 μm, determined by laser scattering;
- a further type of particulate amorphous silicon dioxide has a particle size distribution with a median value in the range 0.7 to 1.5 μm, determined by laser scattering,
- one, two, three or more or all of the different types of particulate amorphous silicon dioxide are
- Particulate synthetic amorphous silicon dioxide, preferably producible by reducing quartz in an electric arc furnace, comprising a total mass of particulate synthetic amorphous silicon dioxide and at least carbon as a secondary component Particulate synthetic amorphous silicon dioxide containing silicon dioxide in a proportion of at least 80% by weight based on
- particulate synthetic amorphous silicon dioxide containing zirconium oxide as a secondary component and preferably producible by pyrolysis of _ZrSiO4 ,
- particulate synthetic amorphous silicon dioxide, producible by oxidation of metallic silicon with an oxygen-containing gas,
- a process according to aspect 35, selected from or independently selected from the group consisting of particulate synthetic amorphous silicon dioxide producible by quenching a silicon dioxide melt.

42. - a further type of particulate amorphous silicon dioxide has a particle size distribution with a median value in the range 0.7 to 1.5 μm, determined by laser scattering,
- one, two, three or more or all of the different types of particulate amorphous silicon dioxide are
- Particulate synthetic amorphous silicon dioxide, preferably producible by reducing quartz in an electric arc furnace, comprising a total mass of particulate synthetic amorphous silicon dioxide and at least carbon as a secondary component Particulate synthetic amorphous silicon dioxide containing silicon dioxide in a proportion of at least 80% by weight based on
- particulate synthetic amorphous silicon dioxide containing zirconium oxide as a secondary component and preferably producible by pyrolysis of _ZrSiO4 ,
- particulate synthetic amorphous silicon dioxide, producible by oxidation of metallic silicon with an oxygen-containing gas,
- a process according to aspect 35, selected from or independently selected from the group consisting of particulate synthetic amorphous silicon dioxide producible by quenching a silicon dioxide melt.

43. Preferably, at least 90% of the grains of the granules have a particle size of more than 0.2 mm, preferably more than 0.5 mm, more preferably more than 1 mm, each determined by sieving (especially VDG-Merkblatt P 27, see above) by X-ray fluorescence analysis, for example according to DIN EN ISO 12677, DIN 51001, optionally in combination with optical and/or spectroscopic methods and/or wet chemical methods. , including both or at least two different types of particulate amorphous silicon dioxide, and the skilled artisan will select a preferred and appropriate determination method with knowledge of the materials used in the process, any of aspects 35-42 The process depends on.

44. The enlargement step is
- granulation,
- a process according to one of the above aspects comprising one or more means independently selected from the group consisting of - extrusion, and - agglomeration.

45. Granules having an average particle size of greater than 0.2 mm as determined by sieving for the production of injectable additives for use as components of inorganic binders in the foundry industry, comprising particulate amorphous silicon dioxide being a thing,
(a) one, two or more additional materials,
- preferably oxides of aluminum, preferably alpha-phase aluminum oxide, bauxite, oxides of zirconium, preferably zirconium(IV) oxide, aluminum/silicon mixed oxides, zinc oxide, barium sulphate, phosphorus compounds, sheet silicates, graphite , carbon black, glass beads, oxides of magnesium, borosilicates, ceramic hollow beads, boron oxide compounds, preferably powdered boron oxide compounds and mixtures thereof, preferably particulate inorganic material,
- water-soluble materials,
- an alkali metal hydroxide,
- surfactants,
- a film former,
- hydrophobizing agents, preferably adding one, two or more further materials independently selected from the group consisting of organosilicon compounds, silanes, silicones and siloxanes, waxes, paraffins, metal soaps, and - carbohydrates. at least 90% of the grains of the granules having a particle size larger than 0.2 mm, preferably larger than 0.5 mm, more preferably larger than 1 mm, determined in each case by sieving, are particulate comprising amorphous silicon dioxide and one, two or more of said further materials; and/or (b) the particulate amorphous silicon dioxide comprises of at least 80% by weight of silicon dioxide, preferably consisting entirely or partially of particulate synthetic amorphous silicon dioxide and/or (c) determined by X-ray fluorescence analysis The proportion of silicon dioxide in the total and the proportion of silicon dioxide in at least 90% of the grains of the granules having a grain size greater than 1 mm, determined in each case by sieving and subsequent X-ray fluorescence analysis, are defined as granules differ by no more than 30%, preferably differ by no more than 20%, more preferably differ by no more than 10%, based on the proportion of silicon dioxide in the total article, and/or (d) in the particulate article, particulate amorphous The silicon dioxide comprises two or more different types of particulate amorphous silicon dioxide, the two or more types differing by their chemical composition, preferably one of the different types of particulate amorphous silicon dioxide. one, two, three or more or all
- Particulate synthetic amorphous silicon dioxide, preferably producible by reducing quartz in an arc furnace, comprising a total mass of particulate synthetic amorphous silicon dioxide and at least carbon as a secondary component Particulate synthetic amorphous silicon dioxide containing silicon dioxide in a proportion of at least 80% by weight based on
- particulate synthetic amorphous silicon dioxide containing zirconium oxide as a secondary component and preferably producible by pyrolysis of _ZrSiO4 ,
- particulate synthetic amorphous silicon dioxide, producible by oxidation of metallic silicon with an oxygen-containing gas,
- is selected from or independently selected from the group consisting of particulate synthetic amorphous silicon dioxide producible by quenching a silicon dioxide melt, and/or (e) the particulate comprises aspects 1-9 or by a process according to any of aspects 20-44.

46. Granules having an average particle size of greater than 0.2 mm as determined by sieving for the production of injectable additives for use as components of inorganic binders in the foundry industry, comprising particulate amorphous silicon dioxide being a thing,
(a) one, two or more additional materials,
- preferably oxides of aluminum, preferably alpha-phase aluminum oxide, bauxite, oxides of zirconium, preferably zirconium(IV) oxide, aluminum/silicon mixed oxides, zinc oxide, barium sulphate, phosphorus compounds, sheet silicates, graphite , carbon black, glass beads, oxides of magnesium, borosilicates, ceramic hollow beads, boron oxide compounds, preferably powdered boron oxide compounds and mixtures thereof, preferably particulate inorganic material,
- water-soluble materials,
- an alkali metal hydroxide,
- surfactants,
- a film former,
- hydrophobizing agents, preferably adding one, two or more further materials independently selected from the group consisting of organosilicon compounds, silanes, silicones and siloxanes, waxes, paraffins, metal soaps, and - carbohydrates. at least 90% of the grains of the granules having a particle size larger than 0.2 mm, preferably larger than 0.5 mm, more preferably larger than 1 mm, determined in each case by sieving, are particulate comprising amorphous silicon dioxide and one, two or more of said further materials;
(b) the particulate amorphous silicon dioxide comprises a proportion of at least 80% by weight of silicon dioxide, based on the total mass of particulate amorphous silicon dioxide, preferably entirely from particulate synthetic amorphous silicon dioxide or become partial,
(c) the proportion of silicon dioxide in the total granules, determined by X-ray fluorescence analysis, and granules with a particle size greater than 1 mm, determined in each case by sieving and subsequent X-ray fluorescence analysis; The proportion of silicon dioxide in at least 90% of the grain differs by no more than 30%, preferably by no more than 20%, more preferably by no more than 10%, based on the proportion of silicon dioxide in the total granule,
(d) in the particulate, the particulate amorphous silicon dioxide comprises two or more different types of particulate amorphous silicon dioxide, the two or more types differing by their chemical composition, preferably , one, two, three or more or all of different types of particulate amorphous silicon dioxide,
- Particulate synthetic amorphous silicon dioxide, preferably producible by reducing quartz in an arc furnace, comprising a total mass of particulate synthetic amorphous silicon dioxide and at least carbon as a secondary component Particulate synthetic amorphous silicon dioxide containing silicon dioxide in a proportion of at least 80% by weight based on
- particulate synthetic amorphous silicon dioxide containing zirconium oxide as a secondary component and preferably producible by pyrolysis of _ZrSiO4 ,
- particulate synthetic amorphous silicon dioxide, producible by oxidation of metallic silicon with an oxygen-containing gas,
- selected from or independently selected from the group consisting of particulate synthetic amorphous silicon dioxide producible by quenching a silicon dioxide melt;
(e) a granulate, wherein the granulate is producible by a process according to any of aspects 1-9 or any of aspects 20-44;

47. Granules having an average particle size of greater than 0.2 mm as determined by sieving for the production of injectable additives for use as components of inorganic binders in the foundry industry, comprising particulate amorphous silicon dioxide being a thing,
- preferably oxides of aluminum, preferably alpha-phase aluminum oxide, bauxite, oxides of zirconium, preferably zirconium(IV) oxide, aluminum/silicon mixed oxides, zinc oxide, barium sulphate, phosphorus compounds, sheet silicates, graphite , carbon black, glass beads, oxides of magnesium, borosilicates, ceramic hollow beads, boron oxide compounds, preferably powdered boron oxide compounds and mixtures thereof, preferably particulate inorganic material,
- water-soluble materials,
- an alkali metal hydroxide,
- surfactants,
- a film former,
- hydrophobizing agents, preferably adding one, two or more further materials independently selected from the group consisting of organosilicon compounds, silanes, silicones and siloxanes, waxes, paraffins, metal soaps, and - carbohydrates. at least 90% of the grains of the granules having a particle size larger than 0.2 mm, preferably larger than 0.5 mm, more preferably larger than 1 mm, determined in each case by sieving, are particulate A granulate comprising amorphous silicon dioxide and one, two or more of said further materials.

48. Granules having an average particle size of greater than 0.2 mm as determined by sieving for the production of injectable additives for use as components of inorganic binders in the foundry industry, comprising particulate amorphous silicon dioxide , wherein the particulate amorphous silicon dioxide comprises a proportion of at least 80% by weight of silicon dioxide, based on the total weight of the particulate amorphous silicon dioxide, preferably from particulate synthetic amorphous silicon dioxide Particulate matter, wholly or partially.

49. Granules having an average particle size of greater than 0.2 mm as determined by sieving for the production of injectable additives for use as components of inorganic binders in the foundry industry, comprising particulate amorphous silicon dioxide granules having a particle size of more than 1 mm, determined in each case by sieving and subsequent X-ray fluorescence analysis The proportion of silicon dioxide in at least 90% of the grains of the article differs by no more than 30%, preferably by no more than 20%, more preferably by no more than 10%, based on the proportion of silicon dioxide in the total grain of the article, particulate matter.

50. Granules having an average particle size of greater than 0.2 mm as determined by sieving for the production of injectable additives for use as components of inorganic binders in the foundry industry, comprising particulate amorphous silicon dioxide A product, wherein in the particulate, the particulate amorphous silicon dioxide comprises two or more different types of particulate amorphous silicon dioxide, the two or more types differing by their chemical composition; Preferably one, two, three or more or all of the different types of particulate amorphous silicon dioxide are
- Particulate synthetic amorphous silicon dioxide, preferably producible by reducing quartz in an arc furnace, comprising a total mass of particulate synthetic amorphous silicon dioxide and at least carbon as a secondary component Particulate synthetic amorphous silicon dioxide containing silicon dioxide in a proportion of at least 80% by weight based on
- particulate synthetic amorphous silicon dioxide containing zirconium oxide as a secondary component and preferably producible by pyrolysis of _ZrSiO4 ,
- particulate synthetic amorphous silicon dioxide, producible by oxidation of metallic silicon with an oxygen-containing gas,
- Particulates selected or independently selected from the group consisting of particulate synthetic amorphous silicon dioxides producible by quenching silicon dioxide melts.

51. Granules having an average particle size of greater than 0.2 mm as determined by sieving for the production of injectable additives for use as components of inorganic binders in the foundry industry, comprising particulate amorphous silicon dioxide A particulate article producible by a process according to any of aspects 1-9 or any of aspects 20-44.

52. a kit comprising, as components in spatially separate arrangements, particulates according to any of aspects 45-51, preferably an inorganic binder, preferably as components in spatially separate arrangements from one another,
- a granulate according to any of aspects 45 to 51; and - a kit for the production of a binder comprising and/or consisting of an inorganic multi-component binder system comprising at least a solution or dispersion comprising water glass.

53. 45. An apparatus for carrying out the process according to any of aspects 1-44, comprising:
- a storage container containing particulate amorphous silicon dioxide, the particulate amorphous silicon dioxide comprising a proportion of at least 80% by weight of silicon dioxide, based on the total weight of the particulate amorphous silicon dioxide;
- a mixing or contacting device for mixing or contacting particulate amorphous silicon dioxide with one, two or more further materials,
- An apparatus comprising a device for granulating, extruding and/or agglomerating particulate amorphous silicon dioxide mixed or contacted with one, two or more additional materials.

54. - a device for transferring particulate amorphous silicon dioxide from a storage container to a mixing or contacting device,
- one or more reservoirs containing a liquid, preferably a liquid wetting agent and/or a suspending medium, preferably water,
- preferably oxides of aluminum, preferably alpha-phase aluminum oxide, bauxite, oxides of zirconium, preferably zirconium(IV) oxide, aluminum/silicon mixed oxides, zinc oxide, barium sulphate, phosphorus compounds, sheet silicates, graphite , carbon black, glass beads, oxides of magnesium, borosilicates, ceramic hollow beads, boron oxide compounds, preferably powdered boron oxide compounds and mixtures thereof, preferably particulate one or more storage containers containing inorganic material;
- one or more reservoirs containing water-soluble materials,
- one or more reservoirs containing one or more surfactants,
- one or more reservoirs containing one or more hydrophobizing agents,
- a device according to aspect 53, additionally comprising one or more device elements selected from the group consisting of one or more reservoirs containing one or more carbohydrates.

55. 55. Apparatus according to aspects 53 or 54, additionally comprising a device for dispensing or transporting the produced particulate matter.

56. Use of particulate amorphous silicon dioxide for the manufacture of granules according to aspects 45-51 or as a component of granules according to aspects 45-51.

57. 52. Use of the granules according to any of aspects 45-51 for producing solid injectable additives having a homogenized grain composition for use as a component of inorganic binders in the foundry industry.

In the following, the invention will be explained in detail with reference to the drawings.

FIG. 1 shows a flow diagram of a first embodiment of the process 100 of the present invention for producing a molding material mixture 107 for use in the foundry industry.

In a first step 101 of process 100, particulate amorphous silicon dioxide, as defined above, is produced or provided.

In a second (expansion) step 102, the particles of particulate amorphous silicon dioxide are combined to provide grains to provide a grain 103 as defined above comprising a plurality of individual grains.

The granulate produced is already the product of the process of the invention.

In a further step 104 the produced granules are brought into direct contact with water glass to provide an inorganic binder 105 . The inorganic binder produced is likewise a product of the process of the invention.

In an additional step 106, the produced inorganic binder 105 is mixed with a refractory molding substrate to yield a molding material mixture 107 as the product of the process of the present invention.

In a further step 108 the produced molding material mixture 107 is molded and (at least partially) cured to yield a molded article 109 as a product of the process of the invention.

FIG. 2 shows a flow diagram of a second embodiment of the process 200 of the present invention for producing a molding material mixture 209 for use in the foundry industry.

In a first step 201 of process 200, particulate amorphous silicon dioxide, as defined above, is produced or provided.

In a second (expansion) step 202, the particles of particulate amorphous silicon dioxide are combined to provide grains to provide a grain 203 as defined above comprising a plurality of individual grains. The granulate produced is already the product of the process of the invention.

In a next step 204 , the grains of particulate matter 203 are crushed to form a solid injectable additive 205 . The additive produced is likewise a product of the process of the invention.

In a further step 206 the produced granules are brought into contact with water glass to provide an inorganic binder 207 . The inorganic binder produced is likewise a product of the process of the invention.

In an additional step 208, the produced inorganic binder 207 is mixed with a refractory molding substrate to yield a molding material mixture 209 as the product of the process of the present invention.

In a further step 210, the produced molding material mixture 209 is molded and (at least partially) cured to yield a molding 211 as a product of the process of the invention.

FIG. 3 shows a flow diagram of another embodiment of the process 300 of the present invention for producing a molding material mixture 309 for use in the foundry industry.

In a first step 301 of process 300, particulate amorphous silicon dioxide, as defined above, is produced or provided.

In another step 301a, further material is produced or provided (aspect 27 and as defined above).

In a following (expansion) step 302, the particles of particulate amorphous silicon dioxide are combined into granules, where further materials produced or provided in step 301a are added before or during step 302a and the expansion step , the particles of particulate amorphous silicon dioxide are mixed and/or brought into contact with these additional materials, resulting in an expansion step in the granules 303 defined above comprising a plurality of individual grains. These individual grains contain particulate amorphous silicon dioxide and additional materials. The granulate produced is already the product of the process of the invention.

In a subsequent step 304 , the grains of particulate matter 303 are crushed to form a solid injectable additive 305 . The additive produced is likewise a product of the process of the invention.

In a further step 306 the produced granules are brought into contact with water glass to provide an inorganic binder 307 . The inorganic binder produced is likewise a product of the process of the invention.

In a next step 308, the produced inorganic binder 307 is mixed with a refractory molding substrate to yield a molding material mixture 309 as the product of the process of the present invention.

In a further step 310, the produced molding material mixture 309 is molded and (at least partially) cured to yield a molding 311 as a product of the process of the invention.

Steps 102, 202 and 302 shown in Figures 1, 2 and 3 represent steps essential to each embodiment of the process of the present invention. No model of such a step exists in the prior art.

Example 1 Method for Determining Particle Size Distribution by Laser Scattering It is also possible to determine the particle size distribution or median of .

1.1 Sample preparation:
As an example, granules of silica fume particles (CAS number: 65012-64-2; particulate amorphous silicon dioxide) which are commercially available (RW Silicon GmbH) and are in particulate powder form, especially from Si production The size distribution was determined.

In each case, about 1 teaspoon of this particulate amorphous silicon dioxide is mixed with about 100 mL of demineralized water and the resulting mixture is stirred for 30 seconds at a stirrer speed of 500 revolutions per minute. Stirred using a magnetic stirrer (IKAMAG RET). Afterwards, an ultrasonic probe (from Hielscher; model: UP200HT) pre-adjusted to 100% amplitude and equipped with a S26d7 sonotrode (from Hielscher) was immersed into the sample, thereby sonicating the sample. Sonication was continuous (not pulsed). An optimal sonication time of 300 seconds was chosen for the silica fume particles tested. This was previously determined as described in Example 1, point 1.3 below.

1.2 Laser scattering measurements:
Measurements were performed using a Horiba LA-960 instrument (hereinafter LA-960). For the measurements, the circulation speed was 6, the stirrer speed was 8, the data recording of the sample was 30000, the convergence factor was 15, the mode of distribution was volume, the refractive index (R) was 1.50-0.01i (demineralized 1.33 for the demineralized water dispersion) and the refractive index (B) was set at 1.50-0.01i (1.33 for the demineralized water dispersion). Laser scattering measurements were performed at room temperature (20° C.-25° C.).

The measurement chamber of the LA-960 was filled three-quarters full with demineralized water (maximum filling level). Stirring was then started at the set speed and circulation was switched on to degas the water. A zero measurement was then performed using the specified parameters.

A 0.5-3.0 mL sample was then taken from the central portion of the sample prepared according to point 1.1 of Example 1 immediately after sonication using a disposable pipette. The entire contents of the pipette were then introduced into the measurement chamber such that the red laser transmittance was 80%-90% and the blue laser transmittance was 70%-90%. Measurements were then started. Measurements were evaluated in an automated manner based on specified parameters.

For the tested silica fume particles from Si production, the particle size distribution was confirmed by the median value rounded to two decimal places.

1.3 Determination of optimal sonication time:
The optimal duration of sonication, which depends on the type of sample, is determined by performing a series of measurements with different sonication times for each particle type. This was done by starting with a sonication time of 10 seconds and increasing each time by 10 seconds for every further sample, and by increasing the sonication time as described in Example 1, point 1.2. This is done by determining the respective particle size distribution by laser scattering (LA-960) immediately after termination. By increasing the time of sonication, the median value observed for the particle size distribution initially drops, but eventually rises again at longer sonication times. For sonication as described in Example 1, point 1.1, the sonication time chosen is such that in these series of measurements the smallest median particle size distribution is determined for that particle species. time, and this sonication time is the "optimal" sonication time.

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

The suspension thus produced is pipetted as individual droplets onto a commercial aluminum foil (optionally sprayed with a separating agent) heated to 250° C. on a hotplate. and dried, and the particles of the powder used are combined to form granules to obtain the granules of the present invention. The hotplate is here preferably protected against contamination by an additional layer of aluminum foil (located below the layer in contact with the suspension).

The proportion by mass of particles with a diameter of less than 20 μm as determined by laser scattering in the granules is lower than in particulate amorphous silicon dioxide.

Example 3 - Bulk Density; Reduced Dust Emission An electronic balance (measurement uncertainty ± 0.1 g), a metal graduated cylinder with a volume of (100 ± 0.5) mL and an internal diameter of (45 ± 5) mm and The bulk density is determined using a funnel with closed lower opening (according to DIN EN ISO 60).

The funnel is fixed centrally above the graduated cylinder at a height of 20-30 mm and the sample is thoroughly mixed. About 120-130 mL of sample is introduced into the funnel. Quickly open the closure of the funnel so that the sample material falls into the cylinder. An article with a linear end is used to remove excess sample material from the cylinder and then weigh the contents of the cylinder. The mass of the cylinder contents is m _samples .

Evaluation is performed by the following formula.

Results are reported at 1 g/L.

According to Example 2, granules were produced using synthetic particulate amorphous silicon dioxide having a bulk density of 550 g/L. After drying, the granules of the invention so obtained had an average particle size of 6 mm and a bulk density of 950 g/l.

Upon injection, the granules showed a much lower (fine) dust emission than the starting material, synthetic particulate amorphous silicon dioxide with a bulk density of 550 g/L.

Example 4 - One Hour Strength Testing of Various Test Bars 4.1 Preparation of Molding Material Mixture 4-A 0.80 parts by weight of synthetic particulate amorphous silicon dioxide having a bulk density of about 550 g/L (powder non-granulated; for example Microsilica POS BW 90 LD (Possehl Erzkontor GmbH) or silica fume (Doral Fused Materials Pty., Ltd.); production process in each case: ZrO ₂ and SiO ₂ from ZrSiO ₄ manufactured) was manually mixed with 100 parts by weight of HS 00232 sand (silica sand, from Quarzwerke GmbH, AFS particle size index 47). Then 2.00 parts by weight of a liquid binder based on water glass (commercially available material named Cordis 9032; Huettenes-Albertus Chemische Werke GmbH) are added, the materials used are homogeneously dispersed and a molding material mixture is obtained. All components were mixed together in a bull mixer (type RN 10/20, ex Morek Multiserw) for 120 seconds at 220 revolutions per minute, such that all ingredients were mixed together.

4.2 Preparation of Molding Material Mixture 4-B According to Example 2, using synthetic particulate amorphous silicon dioxide with a bulk density of 550 g/L (same material used in Example 4.1) and water to produce granules. The granules so produced were ground for 10 seconds in a blender (Universal Plus MUM 6N11 food processor from Bosch) so as to obtain a solid injectable additive.

0.80 parts by weight of this solid injectable additive was manually mixed with 100 parts by weight of HS 00232 sand (silica sand, from Quarzwerke GmbH, AFS particle size index 47). Then 2.00 parts by weight of a liquid binder based on water glass (commercially available material named Cordis 9032; Huettenes-Albertus Chemische Werke GmbH) are added, the materials used are homogeneously dispersed and a molding material mixture is obtained. All components were mixed together in a bull mixer (type RN 10/20, ex Morek Multiserw) for 120 seconds at 220 revolutions per minute, such that all ingredients were mixed together.

4.3 Preparation of Molding Material Mixture 4-C 20.05 kg of synthetic particulate amorphous silicon dioxide (same as the material used in Example 4.1) having a bulk density of about 550 g/L are placed in a plowshare mixer. (from Gebrueder Loedige 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 plowshare shaft rotation speed of 180 revolutions per minute and a blade head rotation speed of 3000 revolutions per minute for 120 seconds. The blade head was then switched off and mixing was continued at a plowshare shaft rotation speed of 180 revolutions per minute such that soft granules were formed.

A portion of the wet granules was then dried at 105° C. to constant weight so as to obtain (dry) granules. The cooled dry material was then classified by a sieving tower according to VDG-Merkblatt P27 (October 1999) and the fraction below 125 μm was discarded. The sieving yield was about 85%.

Upon injection, the classified granules showed a much lower (fine) dust emission than the starting material, particulate amorphous silicon dioxide having a bulk density of about 550 g/L.

The classified granules so produced were ground for 10 seconds in a blender (Universal Plus MUM 6N11 food processor from Bosch) so as to obtain a solid injectable additive.

0.80 parts by weight of this solid injectable additive was manually mixed with 100 parts by weight of HS 00232 sand (silica sand, from Quarzwerke GmbH, AFS particle size index 47). Then 2.00 parts by weight of a liquid binder based on water glass (commercially available material named Cordis 9032; Huettenes-Albertus Chemische Werke GmbH) are added, the materials used are homogeneously dispersed and a molding material mixture is obtained. All components were mixed together in a bull mixer (type RN 10/20, ex Morek Multiserw) for 120 seconds at 220 revolutions per minute, such that all ingredients were mixed together.

4.4 Production of test bars 22.4 mm x 22 bars from each of the molding material mixtures 4-A, 4-B and 4-C produced according to points 4.1, 4.2 and 4.3 of Example 4. A test bar was formed having dimensions of 0.4 mm x 185 mm. For this purpose, using compressed air (4 bar) and a firing time of 3 seconds, the respective molding material mixture was introduced into a mold for test bars with a temperature of 160°C. The test bars were then heat cured at 160° C. for 30 seconds without gas. The mold was then opened and the cured test bars removed and stored to cool.

4.5 Determination of 1 hour strength Test bars produced from molding material mixtures 4-A, 4-B and 4-C according to point 4.4 of Example 4 were placed in a 3-point bending device after a cooling time of 1 hour. (from Morek Multiserw) to measure the force leading to fracture of the test bar. Readings (in N/cm ² ) indicated 1 hour strength. Table 1 shows the results. Each 1-hour intensity number corresponds to the median value from 6 individual measurements.

The results shown in Table 1 show that test bars made with particulate (made by the process of the present invention) or solid injectable additives (made by the process of the present invention) are surprisingly It should be noted that it has a high 1 hour strength.

Example 5 - Preparation of Granules with Uniform Distribution of Additives Similar to the preparation method of Example 2, in several experiments, in each case, in addition to the particulate amorphous silicon dioxide used, and added one or more of the following substances as additional ingredients to produce granules:
- a liquid, preferably a liquid suspension medium, preferably water,
- preferably oxides of aluminum, preferably alpha-phase aluminum oxide, bauxite, oxides of zirconium, preferably zirconium(IV) oxide, aluminum/silicon mixed oxides, zinc oxide, barium sulphate, phosphorus compounds, sheet silicates, graphite , carbon black, glass beads, oxides of magnesium, borosilicates, ceramic hollow beads, boron oxide compounds, preferably powdered boron oxide compounds and mixtures thereof, preferably particulate inorganic material,
- water-soluble materials,
- an alkali metal hydroxide,
- Surfactants, preferably selected from the group consisting of:
- 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-(1,2 ethanediyl)-phenol hydroxyphosphate, poly-(1,2-ethanediyl)-stearyl phosphate, poly-(1,2-ethanediyl) )-oleyl phosphate, polycarboxylate ether (Melpers 0030, BASF) in water, modified polyacrylate (Melpers VP 4547/240L, BASF) in water, 2-ethylhexyl sulfate (Texapon EHS, Cognis) in water, poly glucoside (Glukopon 225 DK, Cognis), sodium octyl sulfate in water (Texapon 842, Lakeland), modified carboxylate ether (Castament ES 60, solid, BASF),
- a film former, preferably polyvinyl alcohol and/or acrylic acid,
- Rheological additives (thickeners, suspension aids), preferably selected from the group consisting of:
- swelling clays, preferably sodium bentonite or attapulgite/palygorskite,
- swellable polymers, preferably cellulose derivatives, especially carboxymethyl, methyl, ethyl, hydroxyethyl and hydroxypropyl cellulose, plant mucilage, polyvinylpyrrolidone, pectin, gelatin, agar, polypeptides and/or alginates,
- Hydrophobizing agents, preferably organosilicon compounds, silanes, silanols, preferably trimethylsilanol, silicones and siloxanes, preferably polydimethylsiloxanes, waxes, paraffins, metal soaps, and - carbohydrates.

In each case granules were obtained in a similar manner. The granules obtained can each be treated by grinding in order to obtain solid injectable additives. Granular or solid injectable additives, respectively, have been successfully processed to obtain molding compound mixtures. These were further processed to obtain test bars.

Claims (20)

- granules for the production of injectable additives for use as components of mineral binders in the foundry industry,
- solid injectable additives for use as components of inorganic binders in the foundry industry,
- inorganic binders for use in the foundry industry,
- molding material mixtures containing inorganic binders for use in the foundry industry; and - moldings for use in the foundry industry for casting metal casting parts. A process for manufacturing comprising the following steps for manufacturing said article:
- producing or providing particulate amorphous silicon dioxide, said particulate amorphous silicon dioxide comprising a proportion of at least 80% by weight of silicon dioxide, based on the total mass of said particulate amorphous silicon dioxide; ,
- a plurality of individual grains, each containing combined grains and each containing a proportion of particulate amorphous silicon dioxide of at least 30% by weight, based on the mass of said respective grain combining the particles of said particulate amorphous silicon dioxide in an enlarging step to provide granules, wherein the average particle size of said granules is determined by sieving to be 0.2 mm A process that contains larger steps. - solid injectable additives for use as components of inorganic binders in the foundry industry,
- inorganic binders for use in the foundry industry,
- molding material mixtures containing inorganic binders for use in the foundry industry; and - moldings for use in the foundry industry for casting metal casting parts. For manufacturing, the following steps:
- producing granules according to the process of claim 1;
- A process according to claim 1, comprising the step of crushing said grains of said particulate material to yield a solid injectable additive. - inorganic binders for use in the foundry industry,
- molding material mixtures containing inorganic binders for use in the foundry industry; and - moldings for use in the foundry industry for casting metal casting parts. is for manufacturing,
(i) the following steps:
- manufacturing said solid injectable additive by the process of claim 1 or 2;
- contacting said produced solid injectable additive with water glass or suspending said produced solid injectable additive in water glass, or (ii) steps:
- producing granules according to the process of claim 1 or 2;
- contacting the produced granules with water glass in the presence or absence of a refractory molding substrate and simultaneously or subsequently crushing the grains of the granules. Described process. For producing a molding material mixture comprising a refractory molding substrate and an inorganic binder comprising water glass and particulate amorphous silicon dioxide for use in the foundry industry, comprising the steps of:
- producing an inorganic binder according to any one of claims 1-3;
(i) simultaneously mixing the components used for the production of the inorganic binder with a refractory molding substrate; and/or (ii) thereafter mixing the produced inorganic binder with the refractory molding substrate. The process of any one of claims 1-3, comprising the step of mixing. a plurality of individual grains, each comprising combined grains and having a proportion of at least 30% by weight, preferably at least 40% by weight, more preferably at least 50% by weight, based on the mass of said respective grains combining said grains of said particulate amorphous silicon dioxide in an expanding step to provide a grain to provide a grain comprising a plurality of individual grains each comprising amorphous silicon dioxide; 2. The process of claim 1, wherein the average particle size of is greater than 0.5 mm, preferably greater than 1 mm as determined by sieving. said particulate amorphous silicon dioxide comprising at least 80% by weight of silicon dioxide, based on the total mass of said particulate amorphous silicon dioxide, entirely or partially from particulate synthetic amorphous silicon dioxide; The process of any one of claims 1-5, comprising: the proportion of silicon dioxide in the total granules, determined by X-ray fluorescence analysis, and in each case greater than 1 mm, preferably greater than 0.5 mm, determined by screening and subsequent X-ray fluorescence analysis; More preferably, the proportion of silicon dioxide in at least 90% of said grains of said granules having a grain size greater than 0.2 mm differs by no more than 30%, based on said proportion of silicon dioxide in said whole granules, A process according to any one of claims 1 to 6, preferably different by no more than 20%, more preferably no more than 10%. In the expanding step, the particles of the particulate amorphous silicon dioxide are:
- a liquid, preferably a liquid wetting agent and/or suspension medium, preferably water,
- preferably oxides of aluminum, preferably alpha-phase aluminum oxide, bauxite, oxides of zirconium, preferably zirconium(IV) oxide, aluminum/silicon mixed oxides, zinc oxide, barium sulphate, phosphorus compounds, sheet silicates, graphite , carbon black, glass beads, oxides of magnesium, borosilicates, ceramic hollow beads, boron oxide compounds, preferably powdered boron oxide compounds and mixtures thereof, preferably particulate inorganic material,
- water-soluble materials,
- an alkali metal hydroxide,
- surfactants,
- a film former,
- Hydrophobizing agents, preferably mixed with one, two or more further materials independently selected from the group consisting of organosilicon compounds, silanes, silicones and siloxanes, waxes, paraffins, metal soaps, and - carbohydrates. and/or contacted. granules of said granulate resulting from said expansion step, preferably said granules having a particle size larger than 1 mm, preferably larger than 0.5 mm, more preferably larger than 0.2 mm, determined in each case by sieving at least 90% of said grains of matter are
(i) particulate amorphous silicon dioxide and one, two, three or more or all of said further solid materials present in said expansion step, and/or (ii) particulate amorphous silicon dioxide Silicon and
- preferably oxides of aluminum, preferably alpha-phase aluminum oxide, bauxite, oxides of zirconium, preferably zirconium(IV) oxide, aluminum/silicon mixed oxides, zinc oxide, barium sulphate, phosphorus compounds, sheet silicates, graphite , carbon black, glass beads, oxides of magnesium, borosilicates, ceramic hollow beads, boron oxide compounds, preferably powdered boron oxide compounds and mixtures thereof, preferably particulate inorganic material,
- water-soluble materials,
- an alkali metal hydroxide,
- surfactants,
- a film former,
- a hydrophobizing agent, preferably one, two or more further materials independently selected from the group consisting of organosilicon compounds, silanes, silicones and siloxanes, waxes, paraffins, metal soaps, and carbohydrates. 9. The process of claim 8, comprising: said producing particulate amorphous silicon dioxide comprising silicon dioxide in a proportion of at least 80% by weight, based on the total weight of said particulate amorphous silicon dioxide,
- comprising mixing two or more different types of particulate amorphous silicon dioxide, said two or more types differing by their particle size distribution and/or their chemical composition, claims 1-9 A process according to any one of (i)—the first type of particulate amorphous silicon dioxide has a particle size distribution with a median value in the range of 0.1 to 0.4 μm as determined by laser scattering;
- a further type of particulate amorphous silicon dioxide has a particle size distribution with a median value in the range of 0.7-1.5 μm as determined by laser scattering, and/or (ii) said different types one, two, three or more or all of the particulate amorphous silicon dioxide of
- particulate synthetic amorphous silicon dioxide, preferably producible by reducing quartz in an electric arc furnace, the total mass of said particulate synthetic amorphous silicon dioxide and at least carbon as a secondary component particulate synthetic amorphous silicon dioxide containing at least 80% by weight of silicon dioxide based on
- particulate synthetic amorphous silicon dioxide containing zirconium oxide as a secondary component and preferably producible by pyrolysis of _ZrSiO4 ,
- particulate synthetic amorphous silicon dioxide, producible by oxidation of metallic silicon with an oxygen-containing gas,
- the process of claim 10, selected or independently selected from the group consisting of: - particulate synthetic amorphous silicon dioxide, producible by quenching a silicon dioxide melt. At least 90% of said grains of said granules having a particle size of greater than 0.2 mm, preferably greater than 0.5 mm, more preferably greater than 1 mm, determined by sieving in each case, are of said different types 12. A process according to claim 10 or 11, comprising both or at least two of particulate amorphous silicon dioxide. The enlarging step includes:
- granulation,
A process according to any one of claims 1 to 12, comprising one or more means independently selected from the group consisting of - extrusion and - agglomeration. Granules having an average particle size of greater than 0.2 mm as determined by sieving for the production of injectable additives for use as components of inorganic binders in the foundry industry, comprising particulate amorphous silicon dioxide being a thing,
(a) one, two or more additional materials,
- preferably oxides of aluminum, preferably alpha-phase aluminum oxide, bauxite, oxides of zirconium, preferably zirconium(IV) oxide, aluminum/silicon mixed oxides, zinc oxide, barium sulphate, phosphorus compounds, sheet silicates, graphite , carbon black, glass beads, oxides of magnesium, borosilicates, ceramic hollow beads, boron oxide compounds, preferably powdered boron oxide compounds and mixtures thereof, preferably particulate inorganic material,
- water-soluble materials,
- an alkali metal hydroxide,
- surfactants,
- a film former,
- hydrophobizing agents, preferably adding one, two or more further materials independently selected from the group consisting of organosilicon compounds, silanes, silicones and siloxanes, waxes, paraffins, metal soaps, and - carbohydrates. at least 90% of the grains of said granules having a grain size of greater than 0.2 mm, preferably greater than 0.5 mm, more preferably greater than 1 mm, determined in each case by sieving, are particles and one, two or more of said further materials, and/or (b) said particulate amorphous silicon dioxide comprises said particulate amorphous silicon dioxide silicon dioxide in a proportion of at least 80% by weight, based on the total weight of, preferably consisting entirely or partially of particulate synthetic amorphous silicon dioxide, and/or (c) as determined by X-ray fluorescence analysis the proportion of silicon dioxide in the total granules and the dioxide in at least 90% of said grains of said granules having a particle size greater than 1 mm, determined in each case by sieving and subsequent X-ray fluorescence analysis The proportion of silicon differs by no more than 30%, preferably by no more than 20%, more preferably by no more than 10%, based on said proportion of silicon dioxide in said total particulate matter, and/or (d) said In the granulate, said particulate amorphous silicon dioxide comprises two or more different types of particulate amorphous silicon dioxide, said two or more types differing by their chemical composition, preferably one, two, three or more or all of the different types of particulate amorphous silicon dioxide,
- particulate synthetic amorphous silicon dioxide, preferably producible by reducing quartz in an electric arc furnace, the total mass of said particulate synthetic amorphous silicon dioxide and at least carbon as a secondary component particulate synthetic amorphous silicon dioxide containing at least 80% by weight of silicon dioxide based on
- particulate synthetic amorphous silicon dioxide containing zirconium oxide as a secondary component and preferably producible by pyrolysis of _ZrSiO4 ,
- particulate synthetic amorphous silicon dioxide, producible by oxidation of metallic silicon with an oxygen-containing gas,
- selected from or independently selected from the group consisting of particulate synthetic amorphous silicon dioxide producible by quenching a silicon dioxide melt; or granules, which are producible by the process of any one of 6-13. as components in mutually spatially distinct arrangements,
- a granule according to claim 14; and - a kit for the production of inorganic binders, comprising at least a solution or dispersion containing water glass. A device for carrying out the process according to any one of claims 1 to 13, comprising:
- a storage container containing particulate amorphous silicon dioxide, said particulate amorphous silicon dioxide comprising a proportion of at least 80% by weight of silicon dioxide, based on the total mass of said particulate amorphous silicon dioxide;
- a mixing or contacting device for mixing or contacting said particulate amorphous silicon dioxide with one, two or more further materials,
- An apparatus comprising a device for granulating, extruding and/or agglomerating said particulate amorphous silicon dioxide mixed or contacted with one, two or more further materials. - a device for transferring particulate amorphous silicon dioxide from said storage vessel to said mixing or contacting device;
- one or more reservoirs containing a liquid, preferably a liquid wetting agent and/or a suspending medium, preferably water,
- preferably oxides of aluminum, preferably alpha-phase aluminum oxide, bauxite, oxides of zirconium, preferably zirconium(IV) oxide, aluminum/silicon mixed oxides, zinc oxide, barium sulfate, phosphorus compounds, sheet silicates, graphite , carbon black, glass beads, oxides of magnesium, borosilicates, ceramic hollow beads, boron oxide compounds, preferably powdered boron oxide compounds and mixtures thereof, preferably particulate one or more storage containers containing inorganic material;
- one or more reservoirs containing water-soluble materials,
- one or more reservoirs containing one or more surfactants,
- one or more reservoirs containing one or more hydrophobizing agents,
- A device according to claim 16, additionally comprising one or more device elements selected from the group consisting of one or more reservoirs containing one or more carbohydrates. 18. Apparatus according to claim 16 or 17, additionally comprising a device for dispensing or transporting the produced granules. Use of particulate amorphous silicon dioxide for the manufacture of the granules according to claim 14 or as a component of the granules according to claim 14. 15. Use of granules according to claim 14 for the production of solid injectable additives with homogenized grain composition for use as a component of mineral binders in the foundry industry.

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