DD278919A3 - DENSITY OF CERAMIC FORMKOERPERS AND METHOD OF PREPARING THEM - Google Patents

Abstract

The invention includes dense ceramic moldings and a process for their preparation. The invention relates to new dense ceramic moldings based on glass and quartz, which are based on an intimate mixture of raw materials, which consists of (mass fractions in%) 50 to 70 finely comminuted recycled glass breakage 0.1 to 30 finely comminuted quartz-rich raw material 5 to 40 ton components and the after firing, have a linear thermal expansion coefficient in the temperature range 20 to 100C of about equal to or less than 9.10 6K 1 and a flexural strength of about equal to or greater than 55 MPa. The process of the invention is characterized by a d84 value of the raw material mixture of less than or equal to 0.025 mm and a d99 value of less than or equal to 0.04 mm, a molding compression pressure of between about 10 and 60 MPa, a sintering temperature of between 1 100 and 1 250 K and a furnace run time of about 30 to about 60 minutes. The moldings produced are in particular construction or sanitary ceramic products.

Description

is used; the raw material mixture a d ₈₄ value of the particle size distribution of less than or equal. 0.025mm and a d- _9g less than or equal to 0.04mm; when molding by pressing a free-flowing granules having a moisture content to about 8 parts by mass in% of the pressing pressure between about 10 and about 60MPa; and firing the moldings at a temperature in the range of 1100 to 1250K, preferably without prior drying, wherein the oven cycle time is about 30 to about 60 minutes.

8. The method according to claim 7, characterized in that the raw material mixture has the following constituents (% by mass)

60 to 70, in particular

60 to 65 finely shredded recycling glass breakage,

1 to 27 finely crushed quartz-rich raw material,

10 to 40 tonne component and optionally

0.01 to 0.5 adjusting agent.

9. The method according to claim 7 or 8, characterized in that the temperature profile in the furnace is then increased by the lying between 1100 and 1 250 K sealing fire zone in a comparatively narrow zone to the sealing fire zone by about 50 to about 120 K.

10. The method according to claim 8 or 9, characterized in that the temperature profile in the furnace is subsequently increased by about 50 to about 120 K in a comparatively narrow zone to the sealing fire zone lying between 1100 and 1 250 K.

Field of application of the invention

The invention relates to dense ceramic moldings based on glass and quartz, which are suitable due to their properties as floor and wall tiles or slabs and mosaics, including sanitary ware products. The invention further relates to a production method of these shaped bodies.

Well-known technical solutions

There are already known ceramic non-porous articles, which were produced on the basis of glass / quartz mixtures. Thus, for example, DD-PS Π5104 discloses ceramic articles in which the material to be sintered consists of 25-60% by weight of quartz raw material and 40-75% by weight of SiO ₂ -containing glass. The objects produced from this material have the disadvantage that they are required for use in the construction ceramics as tiles or plates such as mosaic only in the boundary region of the specified glass-quartz composition region in the European Standard 176 expansion coefficient of less than 9 · 10 ~ reach ⁸ K.

In the SU-PS 567704 and 1 214632 dense moldings, in particular facade tiles are described which at firing temperatures below 1 300 K from mixtures on the basis of 62 to 70 wt .-% clay and 10 to 40 wt .-% of a glass frit or Glass breakage and 15 to 25 wt .-% of the waste products from the titanium-manganese enrichment are produced.

Furthermore, dense plate-shaped moldings according to SU-PS 1 263674 are produced from a raw material mixture which contains as main component waste products from the treatment of the rare earths (40-60Ma .-%) and glass breakage (4-15 Ma .-%), chamotte (1-5Ma .-%) and contains clay in proportion up to 100%. Details on the composition of the waste products are not known, as well as there is no indication of the properties of the plates produced in terms of expansion coefficients.

Object of the invention

It is an object of the invention to make the production of tiles and other ceramic products with similar physical parameters by using secondary raw materials much more economical.

Essence of the invention

The invention has for its object to provide by selecting secondary raw materials as starting materials and by means of a low sintering temperature with the simultaneous application of rapid firing new dense ceramic moldings and a process for their preparation. Another part of the task was. To develop moldings with special surface properties.

According to the invention, the new dense ceramic moldings based on glass and quartz are characterized in that, starting from an intimate raw material mixture of 50-70 parts by mass in% comminuted recycling glass breakage, 0.1-30 parts by mass in finely comminuted quartz-rich raw material 5 40 mass fractions in% of clay component and optionally 0.01-0.5 mass% of adjuvant, after firing the following physical properties: linear thermal expansion coefficient in the temperature range 20 to 100 ° C (measured according to European Standard EN 176) equal to or less than about 9 · 10 " ⁶ K" ¹ , flexural strength (three point bend test) equal to or greater than about 55MPa. According to the invention, the finely comminuted Recycüngglasbruch of commercially available colored or white container glass and / or flat glass whose grain size is at least 90% less than 0.04mm, the d ₅₀ value is between 0.020 and 0.005 mm, preferably below 0.015mm, and its linearerthermischer Coefficient of expansion in the temperature range 50 to 400 ^° C. is equal to or less than about 9 · 10 ^-6 K, whose transformation temperature is equal to or less than 840 K and whose chemical composition is in the following ranges (% by mass)

SiO ₂ 69-73 Al ₂ O ₃ 0.1-3.5 Fe ₂ O ₃ 0.02 to 0.9 CaO 5-10 - MgO 1,5-6 - Na ₂ O 12-16 K ₂ O 0.1-1.5.

CaO + MgO 9-12 Na ₂ O + K ₂ 013-16

other impurities (e.g., Mn, Ti, Cu-Pb) less than 1.5, based on each individual impurity.

Recycled glass breakage is understood to mean copious glass breakage from container glass, flat glass and / or building glass, with small amounts (less than about 5-10% by weight in mass) of special glass breakage contained therein not disturbing.

The finely comminuted quartz-rich raw material is advantageously such a low quality, preferably a residue of sand and / or kaolin preparation having a quartz content of at least about 75 mass% and a balance of predominantly siliceous constituents, the d2 value of the particle size distribution being less than 0.025 mm, preferably less than 0.020 mm. The content of carbonates should not exceed 2%.

The clay component used according to the invention may be either a sedimentary clay, a bentonite or a treated kaolin, as well as an analogous preparation product with a high clay mineral content. According to the invention, the clay component to 95%, a particle size less than 0.01 mm and at least 50% less than 0.001 mm, preferably 50% less than 0.0003 mm. The specified grain sizes for glass, quartz and clay ensure that a readily processable, homogeneous slip, a good compressible granules and moldings are obtained, which have a sufficient Rohbruchfestigkeit, densely sintered at temperatures below 1 300 K and optionally in the same sintering process at the Surface can be provided with a self-glaze effect.

Surprisingly, it has been found that the inclusion of the clay component in the glass / quartz system can result in the formation of new phases whose coefficient of expansion may degrade the linear thermal expansion behavior of the dense ceramic moldings, with an interaction for temperature control being observed during the sintering process. The resulting due to the clay content during the sintering process new phases can be suppressed by short sintering times, so that dense sintered bodies with expansion coefficients of about equal to or less than 9 10 " ⁶ K" ¹ can be obtained by suitable temperature control. The term "about

9 x 10 ^-6 K " ¹ " means that small deviations of 1 to 2% upwards are still considered within the scope of the invention.

Moldings in which the body is fired from a raw material mixture consisting of 57 to 65 parts by mass in% finely comminuted recycled glass fracture, 20 to 24 parts by mass in finely comminuted quartz-rich raw material, have proven to be preferred for the production of bodies via the path of granules.

10 to 15 mass fractions in% clay component and optionally 0.01 to 0.5 parts by mass in% adjusting agent

consists.

Particularly suitable for the production of tiles is an inventive raw material mixture of (mass fractions in%) 60 to 70, preferably 60 to 65, finely comminuted reclaimed glass breakage, 10 to 40 ton component

1 to 27 finely comminuted quartz-rich raw material and optionally

0.01 to 0.5 adjusting agent. Such a mixture has a linear thermal expansion coefficient in the temperature range of 20 to 100 ° C, equal to or less than 8.7 · 10 " ⁶ K" ¹ and a bending strength equal to or greater than 65 MPa after firing. A particularly preferred shaped article according to the invention has, after firing (sintering), a matt-glossy to shiny self-glaze. Advantageously, such a shaped body has a very good strength, a water absorption of less than about 0.2% by weight and a Mohs scratch hardness of more than about 6. Such values, however, also achieve shaped articles according to the invention without self-glaze

 Preferably, the shaped body according to the invention is present as a plate-shaped material, for. As a tile or mosaic, with all of the

Europanorm EN 176 required for this subject chemical and physical parameters, but also hollow body, such. As typical for sanitary ware, with appropriate wall thicknesses of 2 to average 8 mm and adapted to temperature control during firing produced. The molding according to the invention is in particular a body which can be produced by rapid firing.

Another essential feature of the invention is a method for producing dense ceramic shaped bodies by grinding the raw materials and / or a raw material mixture, shaping, optionally glazing, firing the raw-glazed or unglazed molding, characterized in that a raw material mixture consisting of (% by mass)

50 to 70 finely shredded recycled glass breakage

0.1 to 30 finely crushed quartz-rich raw material

5 to 40 tonne component and optionally

0.01 to 0.5 adjusting agent

is used; the raw material mixture has a d ^ value of particle size distribution of less than or equal to 0.025 mm and a d ₉₉ value of less than or equal to 0.04 mm;

when molding by pressing a free-flowing granules having a moisture content to about 8 parts by mass in% of the pressing pressure between about 10 and about 60 MPa; and firing the shaped bodies at a temperature in the range of 1100 to 1250 K, preferably without prior drying, wherein the furnace transit time is about 30 to about 60 minutes. A preferred raw material mixture in connection with the process according to the invention has the following constituents (% by mass)

57 to 65 finely shredded recycling glass breakage,

20 to 24 finely crushed quartz-rich raw material,

10 to 15 tonne component and optionally

0.01 to 0.5 actuating means,

and is particularly suitable for shaping by pressing a granulate.

Another preferred mixture of raw materials, which is particularly suitable for the production of tiles in rapid firing process, consists of (mass fractions in%)

60 to 70, preferably 60 to 65, finely comminuted recycling glass breakage

1 to 27 finely crushed quartz-rich raw material

10 to 40 tonne component and optionally

0.01 to 0.5 actuating means,

wherein after firing, a linear thermal expansion coefficient in the temperature range of 20 to 100 ^° C, equal to or smaller than 8.8 x 10 ^-6 K ^-1 and a flexural strength equal to or greater than 65 MPa is achieved.

In general, the process of the invention can be run by known dry or wet milling processes. Preferably, a separate dry grinding of the glass component and a brief wet grinding of the entire raw material mixture to a homogeneous, sprayable slurry.

A preferred variant of the method is that the temperature profile in the furnace is subsequently increased by about 50 to about 120K in a narrow region relative to the sealing firing zone, to the sealing firing zone lying between 1100 and 1 250K. This short-term increase in the firing temperature at the surface of the molded body obtained from unglazed Rohformkörpern in Einbrandverfahren a dull glossy to shiny self-glaze and achieved savings by eliminating the process step of the glaze order and the corresponding material costs. Particularly preferred in this method are mixtures of raw materials with more than 60 mass fractions in% glass component.

For the process according to the invention, preferred furnace throughput times are between about 30 and about 45 minutes. For shorter times, material defects in the shaped body result from e.g. non-fired areas when the wall thicknesses of the material are over 3mm. Accordingly, thinner moldings would also allow furnace throughput times of less than 30 minutes, but have little significance in connection with the field of application provided here.

The furnace throughput times mentioned always refer to the entry of the molding at ambient temperature (about 280 to 300K) into the furnace and the exit of the molding at about 470-500 K from the furnace.

The properties and production conditions of the shaped bodies according to the invention result in particular in the following advantages:

- due to the high strength, the material thicknesses for certain applications (eg floor tiles) can be reduced

- By lowering the sintering temperature and the possibility of extremely short sintering time can save fuel costs on the one hand and z. B. for plate-shaped body roller conveyor furnaces with metal rollers are used, which are almost free of wear

it is possible to produce self-glazed moldings having a scratch hardness of greater than 6, thereby achieving further material savings and process and property improvements

- The drying of the compacts, which is usually required for dry pressing and rapid firing processes, can be dispensed with in the compositions according to the invention

- As starting materials, cheap and secondary raw materials are used.

embodiments

The invention will be explained in more detail by the following embodiments, wherein it is not limited to these examples.

example 1

The glass raw material used was green bottle glass with the chemical composition in mass fractions in%:

SiO ₂ 70.3 Al ₂ O ₃ 2.7 Fe ₂ O ₃ 0.42 CaO 8.2 MgO 2.54 Na ₂ O 14.1 K ₂ O 0.67 TiO ₂ 0.1

24 kg of said glass are ground in a 100-l ball mill with 120 kg sintered corundum balls (KER 710) as grinding media with the addition of 0.5% distilled water (based on the dry matter) for 38 hours. The ground product, the grain through-values ds4 = 0.021 mm, d = 0,0069mm _so and a sieve residue on a 0.04 mm sieve of 0.8% by mass on.

As a quartz component, sediment from the kaolin preparation with the following mineral composition in mass fractions in% is used:

quartz 85 to 87 kaolinite 13bis14 Mica u. feldspar Max. 1

This quartz component is comminuted by wet grinding to the grain transmission values d & j = 0.02 mm and dso = 0.0085 mm.

As a clay component, a clay of Friedland with a mineral composition of (in mass fractions in%) about 17 quartz

about 10 kaolinite and

71 Three-layer clay minerals (main constituent: illite-montmorillonite exchange storage mineral) as well as accessories as rest and with the

Grain size passage values d _S 4 = 0.0036mm

d ₅₀ = 0.0003 mm used

 The raw materials become the following shares

Glass 65 parts by weight

Quartz raw material 25 parts by weight clay 10 parts by mass

and with the addition of 0.2 parts by weight of Na-carboxymethylcellulose in% and of water to a solids / liquid ratio of 60:40 by grinding for three hours in a 100-l ball mill with sintered corundum balls (KER 710) to a sprayable slurry mixed. The mixture has the following grain passage values (see also Table 1): d48 = 0.014 mm d ₅₀ = 0.0051 mm

The further processing is carried out by spray drying, dry pressing of the obtained granules and sintering of the raw molded bodies in a rapid heating furnace.

Measured values which characterize these technological processing steps as well as the properties of the ceramic shaped bodies are summarized under Example 1 in Table 1.

Example 2

As raw materials, the offset components specified in Example 1 are mixed in the following proportions in%:

Glass 60 parts by weight

Quartz raw material 25 parts by mass

Clay 15 parts by weight

Na carboxymethyl cellulose 0.1 parts by mass

The processing of the mixture is carried out as described in Example 1. Measured values which characterize the technological processing steps and selected properties of the ceramic shaped bodies are given in Example 2 of Table 1.

Example 3

As raw materials, the offset components specified in Example 1 are mixed in the following proportions in%:

Glass 60 parts by weight

Quartz raw material 20 parts by mass

Clay 20 parts by weight

Na carboxymethyl cellulose 0.1 parts by mass

The further processing is carried out as described in Example 1. Measured values which characterize the technological processing steps and selected properties of the ceramic shaped bodies are given in Example 3 of Table 1.

Example 4

As raw materials, the offset components specified in Example 1 are mixed to the following proportions in% with the addition of water (solid-liquid ratio 60:40).

Glass 50 parts by weight

Quartz raw material 20 parts by mass

Toned component 30 parts by weight

The further processing is carried out as described in Example 1.

Further details which characterize the technological processing process and selected properties of the corresponding ceramic shaped bodies are summarized under Example 4 of Table 1.

Example 5

As raw materials, the offset components specified in Example 1 are mixed to the following proportions in% with the addition of water (solid-liquid ratio 55:45):

Glass 60 parts by weight

Clay 40 mass parts

Further processing is as described in Example 1.

Measured values characterizing the processing technology and the material properties are shown in Table 1 under Example 5.

Example 6

The glass raw material used is a colorless glass powder with the following chemical composition in mass fractions in%:

SiO ₂ 72.5 Al ₂ O ₃ 1.3 Fe ₂ O ₃ 0.2 CaO 7.6 MgO 3.7 Na ₂ O 13.8 K ₂ O 0.3 TiO ₂ 0.04

The glass flour has the grain transmission values d ^ = 0.038 mm, d ₅₀ = 0.021 mm and d ₁₆ = 0.007 mm.

The quartz raw material used is a sediment from the kaolin preparation with a mineral composition of 95% by mass in% quartz and 5% by mass in% clay minerals (mainly HMt and mica).

As a clay component, kaolin with a mineral composition such as (in% by weight) about 17 quartz

42 kaolinite and

37 Three-layer clay minerals (mostly illite-montmorillonite exchange storage mineral) as well as some feldspar and others

accessory components used.

The grain transmission values of the clay component are da4 = 0.0050 mm and

d ₅₀ = 0.0007 mm.

8 kg of the quartz-rich and clay raw material are ground in a 100 l ball mill with 120 kg KER 710 sintered corundum balls with the addition of 17 kg of water. The grain passage values are U ₈₄ = 0.011 mm and d ₅₀ = 0.003 mm. After addition of 24kg glass powder for wet grinding of the quartz-rich and clayey raw material components, so that a mixture to proportions of

60 mass fractions in% glass, 20 mass fractions in% quartz raw material and 20 mass fractions in% Seilitzer kaolin is present.

after a mixed grinding, a sprayable slurry with the grain permeation values (see Table 1)

ds4 = 0.021 mm d5o = 0.009 mm d _ie = 0.0012mm

receive. The further processing is carried out by spray drying, dry pressing of the obtained granules and sintering of the raw molded bodies in a rapid heating furnace.

Measured values which characterize these technological processing steps and the material properties are given in Table 1 under Example 6.

Example 7

As raw materials, the offset components specified in Example 6 are used in the following proportions in%.

Glass flour 60 parts by mass

Seilitzer kaolin 40 parts by weight

with the addition of water (solid-liquid ratio 65:35) for four and a half hours in a ball mill to form a homogeneous and sprayable slurry.

Further processing was carried out as described in Example 6. Measured values which characterize the technological processing steps and characterize the material properties are listed in Table 1.

Example 8

As indicated in Example 7, 60 parts of glass flour and 40 parts of kaolin Seilitzer mixed in Ma .-% and processed to a homogeneous slip.

The further processing is carried out by casting a complicated hollow body in plaster molds, pouring excess slurry after about 10 minutes, removing the green body from the mold after blunting, air drying and sintering in a chamber furnace.

The grain passage values of the slurry, the sintering temperature of the ceramic mass and the characteristic properties for the material such as water absorption, linear thermal expansion coefficient, flexural strength and scratch hardness correspond to those of Example 7 of the table

Example 9

The glass raw material used is the glass flour specified in Example 6.

The quartz and clay raw material used is the RossbacherTon grade 2 with a mineral composition such as (in% by weight) about 43 quartz

40 kaolinite 14 Three-layer clay minerals and some feldspar and other accessory ingredients used.

The grain transmission values of the quartz-rich argillaceous component are ds »= 0.018 mm and d ₅₀ = 0.0034 mm.

Per 64kg of the quartz-rich argillaceous raw material are ground in a 300-l ball mill with 160kg of flint stone with the addition of 68kg of water for 5 hours.

After addition of 96 kg of glass powder for wet grinding of the quartz-rich argillaceous raw material component, so that a mixture to proportions of 60 parts by weight in% glass

40% by weight of RoßbacherTon grade 2, after a mixed grinding, a sprayable slip with the grain permeation values (see Table 1) da4 = 0.0193 mm d ₅₀ = 0.0075 mm d ₁₆ = 0.0012 mm is obtained. Further processing is carried out by sputter drying, dry pressing of the obtained granules and sintering of the green shaped bodies in a rapid heating furnace.

Measured values which characterize these technological processing steps and the material properties are given in Table 1 under Example 9.

Example 10

The glass raw material used is the glass flour specified in Example 6.

The quartz material used is the Rossbach clay grade 3 with a mineral composition such as (in% by weight) about 54 quartz 24 kaolinite 18 mica and 2 other minerals.

The grain transmission values of the quartz-rich component are dg4 = 0.04 mm

d ₅₀ = 0.005 mm.

As a clay component, Guttauer clay with a mineral composition such as (in% by weight) about 74 kaolinite 16 three-layer clay minerals 6 quartz

2 other minerals used.

The Komdurchgangswerte the tonigen component da da = 0.0008 mm and

d ₅₀ = 0.0002 mm.

50 g each of the Rossbach clay grade 3 and 30 g of the clay raw material were ground in a 1 l vibration ball mill with sintered corundum balls of the type KER 710 with the addition of 130 g of water. The grain passage values are d ^ = 0.0085 mm and d ₅₀ = 0.0011 mm.

After addition of 120 g of glass powder for wet grinding of the quartz-rich and clayey raw material components, so that a mixture to proportions of 60 parts by weight in% glass 25 parts by weight in% Roßbacher clay variety and

15 mass fractions in% Guttauer clay is present, after a mixed grinding a sprayable slurry with the grain throughput values (see Table 1) djj4 = 0.019 mm d _so = 0.007 mm d ₁₆ = 0.0025 mm is obtained.

The further processing is carried out by spray drying, dry pressing of the obtained granules and sintering of the raw molded bodies in a rapid heating furnace.

Measured values which characterize these technological processing steps and the material properties are given in Table 1 under Example 10.

Table 1: Measured values for the technological processing steps and selected characteristics of the materials

Example Nr .: 1 2 3 4 5 6 7 8th 9 Grain passage values d. keram. Mass in mm ds4 dso 0.014 0.005 0.014 0.0048 0.013 0.004 0.012 0.004 0.012 0.003 0.021 0.009 0.013 0.004 0.019 0.008 0.019 0.007 Pressing humidity in% 4.0 7.2 a) 6,6 b) 4,8 4.7 5.7 8.0 7.1 1.9 5.5 Pressing pressure in MPa a) 25 b) 36 40 a, b) 40 40 40 40 40 16 40 40 Dry bending strength in MPa a) 1.6 b) 2.1 3.2 a) 5.2 b) 3.1 5.1 6.6 2.1 3.5 1.0 1.6 2.1 Heating rate near the sintering temp. in K / mm a) 25 b) 7 25 25 25 25 a) 25 b) 7 a) 25 b) 7 25 25 Sintertemp. in K a) 1120 b) 1 090 1190 1180 1250 1190 a) 1 270 b) 1 200 a) 1 270 b) 1190 1275 1300 Water absorption in% tight «0,2) dense (<0.2) dense (<0.2) tight «0,2) tight «0,2) tight «0,2) tight «0,2) tight «0,2) tight «0,2) Li nearer thermal expansion. x 10 ^e i. K " ¹ 8.6 8.6 8.4 9.1 8.5 8.6 8.5 8.6 8.9 Flexural. d. Sintered body in MPa 67 79 74 68 70 65 73 76 86 Scratch hardness after Mohs 7 7 7 6-7 6-7 7 7 6-7 6-7

Claims (7)

claims: 1. Dense ceramic moldings based on glass and quartz, characterized in that the bodies, based on an intimate raw material mixture of 50 to 70 parts by weight in% finely comminuted recycling glass breakage, 0.1 to 30 parts by weight in finely comminuted quartz-rich raw material, 5 to 40 parts by mass in% of a single-tone component and optionally 0.01 to 0.5 parts by mass in% of adjusting agent, have the following physical properties after firing: linear thermal expansion coefficient in the temperature range 20 to 100 ⁰ C (EN 176) less than about 9 10 ~ ⁶ K ~ ¹ , flexural strength (three-point bending test) equal to or greater than about 55 MPa. 2. Shaped body according to claim 1, characterized in that the finely shredded recycled glass breakage of commercially available colored or white container glass and / or flat glass whose particle size is at least 90% less than 0.04mm, wherein the d ₅₀ value between 0.020 and 0.005mm is, preferably below 0.015 mm, and whose linear thermal expansion coefficient in the temperature interval 50 to 400 ° C is equal to or less than about 9 · 10 ~ ⁶ K ~ ¹ , whose transformation temperature is equal to or less than 840 K and its chemical composition in the following ranges lies (mass fractions in%) CaO + MgO 9-12
Na ₂ O + K ₂ O 13-16 other impurities (e.g., Mn, Ti, Cu, Pb) less than 1.5, based on each individual impurity. 3. Shaped body according to claim 1, characterized in that the finely crushed quartz-rich raw material is such a lower, preferably a residue of sand and / or kaolin processing with a quartz content of at least about 75 mass% and a balance of predominantly silicate components, said the d ^ value of the particle size distribution is less than 0.025 mm, preferably less than 0.020 mm. 4. Shaped body according to claim 1, characterized in that the clay component to 95% has a particle size smaller than 0.01 mm and at least 50% smaller than 0.001 mm, preferably 50% smaller than 0.0003 mm. 5. Shaped body according to one or more of claims 1 to 4, characterized in that the body, based on an intimate raw material mixture of (mass fractions in%) 60 to 70, in particular 60 to 65 finely shredded recycling glass breakage, 1 to 27 finely crushed quartz-rich raw material, 10 to 40 tonne component and optionally 0.01 to 0.5 actuating means, have the following physical properties after firing: linearerthermischer expansion coefficient in the temperature interval 20 to 100 ⁰ C equal to or less than 8.8 · 10 ^-6 K ^-1, flexural strength equal to or greater 65MPa. 6. Shaped body according to one or more of claims 1 to 5, characterized in that they have a matte glossy to shiny self-glaze after firing and a water absorption of less than about 0.2 parts by mass in% and a scratch hardness to Mohs of about about 6 have , 7. A process for producing dense ceramic shaped bodies by grinding the raw materials and / or a mixture of raw materials, shaping, optionally glazing, firing the raw-glazed or unglazed molding, characterized in that a mixture of raw materials, consisting of (mass fractions in%) 50 to 70 finely shredded recycled glass breakage 0.1 to 30 finely crushed quartz-rich raw material 5 to 40 tonne component and optionally 0.01 to 0.5 adjusting agent