DE1961144A1 - Process for the production of pressed tiles - Google Patents

Description

description
to the patent application

2 / 197b

of the company Ciments Lafarge Soci ^ te Anonyme, 28 rue Emile Menier, Paris, France

Concerning:

"Process for the production of pressed tiles and slabs"

The present invention relates to a method for the production of pressed tiles and slabs, for the implementation thereof a molding compound is used, the main component of which consists of a synthetic monocalcium silicate compound, the main component of which is monocalcium silicate in a mixture with aluminum silicates and optionally alkali silicates and other additives contains. The synthetic monocalcium silicate compound hereinafter referred to as "synthetic silicate" or "CS" for short represents a new industrial product which, in addition to the known beneficial properties of the so-called pseudo-wollastonite and the naturally occurring wollastonite also has other advantageous properties, so that it is of is of very great industrial interest.

The naturally occurring wollastonite has been around for a long time known for the production of fine ceramic products, e.g. cladding panels, e.g. tiles, as well as various other products useful in various fields of electrical engineering. The natural wollastonite has

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however, the disadvantage that it is very expensive, so that numerous attempts have been made to find cheaper substitutes which, if not all, at least most of the quality features and advantageous properties de ^; s natural wollastonite, especially with regard to the processability into cladding panels and sanitary industrial products.

Numerous investigations were aimed at attempts to produce a synthetic wollastonite, ie a substance whose composition corresponds to that of naturally occurring wollastonite. Such studies have been carried out using raw materials rich in silica and calcium oxide obtained in the manufacture of aluminum from alumina. It was possible to produce a crystallized compound in the form of a white powder that is very finely granulated using frits without melting at a maximum temperature of 1180 C. The X-ray analysis shows that the composition of the compound obtained in this way corresponds to that of natural wollastonite. It was also found that this synthetic _{wollastonite, corresponding to the formula CaO, ßSiO 2, can} be used in the same way as the natural wollastonite for the production of cladding panels. This means an economic advantage, since the synthetic wollastonite, due to its homogeneity, facilitates the standardization of the manufacturing process, enables the pressing process to be accelerated to a certain extent and is also significantly cheaper than. the natural wollastonite. When processing this synthetic wollastonite by known processes, however, it must be ensured that the firing of the shaped bodies formed is carried out at a temperature at which no glass formation occurs and no absorption below about 5% occurs.

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An attempt was therefore made to connect to the has at least the same quality features and advantages as natural wollastonite and pseudo-wollastonite, which however has the advantage of being more versatile and can be manufactured at lower manufacturing costs.

In the course of these investigations it has now been found that such a silicate compound can be produced by a method which runs counter to the teachings of the known prior art, namely in such a way that a synthetic silicate is produced by using aluminum silicates and calcium oxide of the type CaO, ° ** SiO ₂ melts, then the molten mass, optionally with quenching with air or water, is cooled and then the cooled mass is ground to a fine powder which can be used for the production of ceramic, optionally enamelled industrial products.

In each case, the process of the invention for the preparation of the synthetic silicate is carried out essentially in such a way that, preferably in a glass melting furnace or back-reflecting furnace, a mixture of aluminum silicates! and calcium oxide and, if necessary, further additives melt at a temperature of about 100 to 160O ⁰ C, bring the resulting mixture to complete melting after drying and decarbonization and converted into a free-flowing state like a molten glass bath, withdrawing the resulting melt continuously or discontinuously in this way that, depending on the cooling conditions, a glass-like product is obtained by quenching or a partially crystallized product is obtained by slow cooling and finally the cooled silicate compound is ground.

The synthetic silicate obtained by fusing the starting substances at temperatures from about 100 to 1600 ° C., preferably from about 1550 ° C., is optionally quenched

with air or water, a vitreous, dem Bottle glass is an analog product that crystallized 5 to 30%, may contain parts consisting partly of pseudo-wollastonite. The vitreous synthetic silicate according to the Invention usually contains 50 to 90% monocalcium silicate in a mixture with alkali silicates, aluminum silicates and calcium oxide.

The resulting according to the invention when grinding the glassy synthetic silicate white powder is used as starting substance ψ for producing various industrial products.

The vitreous, "practically non-crystallized monocalcium silicate compound according to the invention is a new product that consists of 45 to 60% silicon dioxide, 30 to 45% calcium oxide and 0 to 15% aluminum oxide, for example in the form of a calcium and aluminum silicate , and which can also contain 0 to 3% iron oxide and, optionally also in the form of silicates, about 0 to 3% magnesium oxide and about 0 to 6% K ^ O and / or Na ₂ O, and which has a ratio of silicon dioxide / Calcium oxide from 1 to 2, preferably from about 1.5, has.

The synthetic silicate according to the invention has for chemical The compound of calcium and aluminum silicate has a characteristic Representation point, which is located in the interior of a 2one in the vicinity of the "CS" point of the triangle diagram of Silicon dioxide-aluminum oxide-calcium oxide is located. It was found that the vitreous synthetic silicate according to the invention, the by melting and cooling the melt with quenching Air or water is obtained, after grinding an aqueous one Suspension results, the pH of which is not above 11 and is therefore lower than that of corresponding suspensions, which by

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Frits of the obtained silicates were obtained. It was also found that in the fused synthetic silicate after Invention to distinguish it from the well-known fried products all of the calcium oxide is bound as well as the silicon dioxide.

The invention also relates to the use of the specified synthetic silicates for the production of industrial products. For example, the synthetic silicates according to the invention can be mixed with clays for the production of cast or pressed Shaped bodies, in particular for sanitary industrial products, e.g. bathtubs, sinks, sinks, bidets and the like Moldings and used for the production of cladding panels will.

Another advantage of the synthetic silicate according to the invention is that it is due to the advantageous pH suspensions made from it can be processed in clay pots without causing flocculation.

Furthermore, the synthetic silicate according to the invention has the remarkably advantageous property that, with the addition aluminum-containing cement can be processed into mortar, which after after drying, preferably at a temperature of about 70 C, has excellent mechanical resistance and allows the desired shaped body to be fired about 2 hours after production. This way are the materials you want can be produced very quickly, i.e. the production time is less than 4 hours, and compared with that using known Products manufactured products fall just very much less scrap.

The synthetic silicate according to the invention can also be used for Manufacture of terracotta products to be used when using

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0 to 80% talc, kaolin and the like are added to the clay. on In this way, porous ceramic products, e.g. filters, can be manufactured.

Furthermore, the synthetic silicate according to the invention can be used as a starting material for the production of fibers, according to the Glass fibers.

It has also been found that the vitreous synthetic silicate according to the invention, if it is in whole or in part, as a rule 20 to 50% by weight, is combined with aluminum-containing cement, can be deformed into shaped bodies which crystallize when fired and which reveal the structure of natural wollastonite mixed with pseudo-wollastonite, as can be seen from the X-ray analysis results. When cooled, the products obtained behave like a mixture of wollastonite and pseudo-wollastonite and are therefore in full agreement with email.

It was possible to establish that the products produced using the synthetic silicate according to the invention have ^{a completely linear expansion between 20 and 800 °} C., which is explained by the fact that the complete combination of calcium oxide and silicon dioxide during melting is prevented that the Siliciumdioxyds ß about its transformation point oC 4- 4 during the cooling of the ceramic products to a change in volume or to changes in the expansion coefficient due deformations

appear.

The results and properties given show that the synthetic silicate according to the invention behaves similarly like naturally occurring wollastonite, in both respects

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on the mechanical resistance in raw and fired Condition, as well as in relation to the pressing behavior through suppression of platelet formation as well as in relation to improving the resistance to thermal shock; also owns the synthetic silicate according to the invention has a thermal behavior that makes it suitable at high temperatures as a refractory To serve as an aggregate or to be used as an abrasive binder.

With regard to industrial use, two types of synthetic silicates according to the invention can be assumed, namely a comparatively poorly refractory silicate with an aluminum content of about 10 to 12%, expressed _{as A ^ O 3, which is obtained, for example, from sand} which has a composition corresponding to the composition of "Arnage", or of a "refractory" silicate with a low aluminum content, which can be obtained, for example, from pebbly so-called "Crau".

The specified two types of synthetic silicate according to the invention can be used in clay vessels for ceramic sanitary products that are cheap, can be fired at low temperatures and usually of an average Email are of appropriate quality.

Furthermore, the specified two types of synthetic silicate according to the invention can be used in mortar or concrete made of flowable Cement used, e.g. in pressed concrete or mortar with low E / C ratio, which can only be processed for simple shapes is, or in a concrete or mortar with an E / C ratio that allows the production of castings.

The "pressed" concrete or mortar mixes have the advantage that they process themselves into panels suitable for sanitary or other purposes within a very short production time let what from the standpoint of industrial economics very much is advantageous. Q0983A / 1687

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When using mortar or concrete mixtures that result in moldings are deniable and the existence of a higher ratio Requiring E / C, ceramic sanitary ware of the usual type or those corresponding to high temperature enamel are obtained.

A very dry mortar, aluminum-containing cement and granules of the synthetic are used to produce pellets Silicate according to the invention pressed into a mold in such a way that a molded body which is sufficiently compact for further processing is obtained, whereupon this treated in the autoclave or treated with steam for a few hours, whereupon he is dried and enamelled. Enamelling is usually carried out in the warm; this is done on the molded body first a first layer consisting of colored earth and then a second layer consisting of enamel of the desired color is applied. After renewed drying, the molding is at the enamel firing temperature, which differs depending on the type of email.

For the manufacture of products obtained by molding a mortar, granules of synthetic silicate according to the invention and aluminous cement become sufficiently plastic Processed mass that enables correct pouring into molds. The moldings obtained are then placed in an autoclave or treated with steam for as long as the hardening time of the cement corresponds, after which it is removed from the molds and under the same conditions as the molded bodies obtained by pressing dried, enamelled and fired.

A mixture can be used to produce ceramic plates that contains:

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a) Synthetic silicate according to the invention, which is the main ingredient and is present in an amount of 50 to 70% by weight, based on the plate to be produced. That used synthetic silicate is ground very finely beforehand;

b) alurainium-containing cement, which in an amount of 20 to

50% by weight, based on the plate to be produced, in the form of Flowable cement is used, e.g. ready-made cement or the cement known under the trade name "SECAR". The ready-made cement represents a mixture of flowable cement F and Portland cement P in the following ratios of F to P: 50-50, 55-45, as well as 60-40 and

c) optionally talc, the amount of which can be up to 50% and is preferably present in an amount of from 0 to 30%.

A typical mixture suitable for the production of ceramic tiles, which proves to be very advantageous, practical and has proven to be economical, has the following composition:

50% synthetic silicate according to the invention 25% aluminous cement
25% talk

The following examples explain and illustrate the invention the production of pellets and moldings »

example 1

For the production of press plates, a mold was made from the dimensions 10 χ 10 cm with a height of 15 mm used »in the a pourable concrete with the following synthetic silicate content was injected under the following conditions:

CS granules 75%

flowable cement 25%

Ratio E / C o, 23

ο
Molding pressure 200 kg / cm

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The used CS granules made of synthetic silicate according to of the invention had the following particle size distribution:

not passable through a percentage sieve of the mesh size
(in mm)

3.15. 0.3

2.00 25

1.60 36

1.00 57

0.50 73

0.315 86

0.200 90

The curing was carried out by steam treatment for 2 hours at 70 ° C. The drying was carried out in such a way that the molded articles exposed to a temperature of 110 ° C for 15 minutes became.

For enamelling, the moldings were initially in several Work steps are provided with a first layer consisting of colored earth, followed by a second layer made of enamel of the desired Color existing layer was applied. The moldings were allowed to dry for a few minutes between the application of the two layers calmly. .

The enamel was finally dried in 20 minutes long treatment carried out at 70 ° C.

The final firing of the shaped bodies took place in a conventional, known, electrically heatable laboratory furnace a firing temperature of 98O ° C and a temperature rise of 3 hours and 30 minutes. Stages of 15 minutes were used and the cooling time was 14 hours.

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It should be emphasized that the specified firing conditions depended on the type of furnace used. The total burning time can obviously be shortened.

Example 2

For the production of molded cast bodies, a shape was made from the dimensions 10 χ 10 χ 2 cm used in the flowable concrete with the following content of synthetic silicate (CS) in the form of Granules was poured under the following conditions:

CS granules 75%

flowable cement 25%
E / C ratio 0.40

The granulometric composition of the CS granules used was the same as that described in Example 1 CS granules.

The specified concrete mass was poured into the mold with the help of a mason's trowel in order to obtain a smooth surface. The molding was hardened for 4 hours in a drying cabinet under steam at 70 C. The drying took place for 15 minutes at 110 C. The enamelling and firing of the Moldings were made according to the method described in Example 1 carried out for the production of pressed slabs or tiles.

High quality panels or tiles were obtained. The results obtained prove the versatile applicability the synthetic silicate obtained by the process of the invention and the technical to be achieved according to the invention Progress. This results in particular from the fact that

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Positioning of molded tiles obtained from flowable cement and porphyry granules according to the usual known methods, the moldings after hardening and drying initially in a time-consuming and costly manner must be fired a first time for 36 hours at 125O ° C, whereupon they have to be burned after the application of a layer of earthenware and a layer of enamel finally
Fired for a second time at 980 C for 13 hours and then cooled down. ~ '

(Patent claim)

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Claims (1)

" ¹³ ""1961H4 Claim Process for the production of pressed tiles and slabs, characterized in / that a molding compound made from a synthetic Monocalciumsilicateverbindungen, consisting of 45 to 60% of silicon dioxide, 30 to 45% of calcium oxide and from 0 to 15% of aluminum oxide in the form of a calcium silicate or a calcium aluminum silicate, which optionally contains about 0 to 3% iron oxide, also in the form of a silicate, as well contains about 0 to 3% magnesium oxide and about 0 to 6% K-O and / or NagO, and which has a ratio of silicon dioxide / calcium oxide from about 1 to 2, preferably from about 1.5, upwards, and furthermore either a clay or a kaolin, or contains a clay putty or an aluminum-containing cement, and optionally contains talc as an additional additive, is used, the pellets obtained are treated in an autoclave or subjected to steam treatment for a few hours Pressings are then dried and finally enamelled, usually in the heat, by first treating them with a first layer consisting of colored earth and then with a second layer consisting of enamel of the desired color Layer provides. 009834/1687