DE968438C - Process for the production of shaped brick bodies in which a ceramic raw material is pressed in granule form using low pressures - Google Patents

Description

A process for the manufacture of brick moldings, in which a ceramic raw material in granule form using low Drue & e is compressed in the patent 864,675 a method for the production of 'brick moldings, in particular bricks hollow block bodies # is described in which a tone or kerainischer raw material in GranaJienform using lower, the structure of the granules or. clay grains largely gentler and only theirs. Edge zones for interpenetrating1), backs, which are maximally in the order of magnitude of v01130 kWCM2, are pressed into a shaped body. The method described in this patent was based on a raw material that is obtained in a crumbly, pourable form when excavating from the Wanct, which can be poured into the mold without any preparation or processing. The moldings pressed from this material show neither the inechaic format, even with large-format bricks up to i: 2 times the imperial format and above, with drying shrinkage. Properties * - noticeably influencing cracks in the finished brick still noticeably uneven dimensional changes. A very large part * of the natural clay deposits do not, however, from the outset have the same properties as for the process described in the main patent. favorable preconditions. For such clay deposits that do not already occur when the wall is excavated in the form of granular, free-flowing material, it is therefore proposed according to the invention that the excavated or stoned material should be passed through. to bring mechanical preparation into the crumbly form; However, the mechanical processing should only consist in granulating the large chunks coming from the wall until they have become free-flowing.

In the refractory industry, in abrasives manufacturing and in the Ziegdlindustrie in the so-called dry pressing it is already loading known to use kerarnische raw materials in granulated form. In these cases, however, the granulated form of the raw material is only chosen in order to obtain easy filling of the mold. In this known method, however, at the high pressures of over 100 kg / cm 2, often up to. 5oo k # / cin2 and more, completely destroyed. At these high pressures, a homogeneous, dense structure is created. This can be clearly seen on a fracture surface of a stone or other object produced by this method, which always shows a smooth, dense body. In contrast to this, the fracture surface of a stone produced according to the method according to the main patent is irregular and runs along the boundary surfaces of the clay granules that are only brought into contact with one another at their points of contact, so that the grain or granule structure of the in the mold is clearly visible in the fracture surface filled tone is to be recognized. In addition, in the known methods which use a raw material in granulated form, any larger clay 'grains present, as well as coarser components and foreign bodies, are sorted out before they are poured into the mold. However, this is not necessary in the method according to the invention.

The mechanical preparation of the material for further processing according to the method described in the main patent can be done in a wide variety of ways. For example, it is possible to crumble the raw material with the help of known clay chippers and / or vibrating sieves. Preferably - the raw material is granulated in such a way that the dimensions and proportions of the resulting clay 'crumbs or clay bodies correspond approximately to the Fuller curve known from concrete construction in analogous transfer of the scales.As is well known, the Fuller curve describes the dimensions and proportions required to meet the cavity minimum the body filling the space. If the mechanical preparation of the clay, possibly with the use of vibrating sieves, is done in such a way that the clay crumbs or grains in the clay material have the same size gradations and are mixed with one another in the same proportions as the Fuller curve in analogous transfer of the scale indicates, the finished bricks will also show the highest compressive strength.

So far it was assumed that the clay deposits were more or less is homogeneous. Now there are many Freindr inclusions in clay, such as Quartz, lime, gravel or other grains contained, or in (Jen TonvoTkommen are individual Shitlites embedded, in which such foreign inclusions are particularly rich occurrence. -As it would be uneconomical to sort out these foreign inclusions, the material obtained from such clay deposits is expediently by means of bring such machines into the desired granular, free-flowing form, which at the same time- shatter these foreign inclusions so that the fragments are equal to or smaller than the clay grains are. Such a disintegration occurs e.g. B. a, if you have a pan mill or a synchronous. or differential. driven rolling mill with or without elastic Coverings used for the mechanical preparation of the material.

Some of the clay deposits have the natural moisture content just on the one hand still so big that when pressing the from the excavation wall or at the granular clay material obtained by mechanical preparation, the edge zones of the individual clay grains can penetrate into one another, but on the other hand already so low that even with large-format brick moldings of, for example 5o cm edge length with the dry shrinkage neither the mechanical properties in the finished brick noticeably influencing cracks still noticeably uneven dimensional changes appear. Such clay materials can be used directly according to the one described in the main patent Process are pressed into brick moldings.

In the case of clay deposits in which the natural moisture is not in The moisture content can be within this range required for the process artificially adjusted to this favorable total moisture content.

If the clay deposit is too moist and not crumbly, for example the humidity can be reduced in a manner known per se in that the material excavated from the wall by air drying or artificial drying before it is mechanically exposed to the desired crumbly or granular clay material is processed.

In the case of a material that is crumbly, but as such is too moist to be processed directly for the procedure, the Desired moisture content can be set by using a natural drying process or artificial drying of the material during or after the mechanical Preparation is made.

It is also possible to mix this crumbly, but too moist clay material before, during or after the mechanical preparation with particularly dry clay in the form of granules, but preferably in the form of dust. -Good mixing obtain a molded article advance set by the local Fetichtigkeitsausgleich Zvi # rule benachbartn Tonkörnern, the GesaintfeuchtigkeitsgehaIt is decisive for its drying shrinkage, so that when properly Misthungsverhä # ltnis of - although in this case an unfavorable moisture content is present in a majority of the clay granules, but is In this case, too, large-format bricks with good strength properties can be obtained with moist and dry material.

. There are also clay deposits in which individual layers are too moist, but those, like very hard, water-impermeable clay layers, are too dry , himself -the one for the procedure. Set a favorable total moisture content.

For a material made by. Nature off. Zit dry and with it only is difficult to plasticize, is proposed according to the invention, before, during or after mechanical preparation, e.g. B. by spraying known per se, to moisten the material in such a way that the edge zones of the individual clay grains become plastic so that they then penetrate into one another during pressing and. in order to can bind. A clay that is too dry to be dealt with in this way may be Certainly also in a clay that was originally too damp and not crumbly after drying can be obtained as this material in order to be cut off large chunks of clay to dry out sufficiently into the inner core Edge areas already for further processing according to the process according to the main patent may have become too dry. Though the small grains of clay due to the moistening and the clay dust become very damp, the total humidity will be adjusted correctly through the local equalization with the neighboring larger ones that have remained dry in the core Clay grains get a shaped body that does not have the mechanical during the drying process Shows cracks influencing properties of the fired brick.

For one that is too dry, especially hard, difficult to plasticize Clay, like slate, is also possible by using the method according to the main patent to make applicable that one plasticized only the fine clay grains and / or fine Clay grains of a crumbly, very moist clay are added, which then act as a binding agent act between the coarser clay grains.

While the ceramic raw materials are first processed into a stiff, homogeneous, compressible mass in the processes mostly used for the production of ceramic moldings, according to the invention the material coming from the wall is only comminuted to such an extent that it. enters into free-flowing form that allows you to fill Preßforrn can, but here in the individual grains the natural structure of the deposit Tonvorkommens - left largely undisturbed as possible. The size of the clay grains depends on the cavities to be filled in the mold. In the case of large cavities, large clay grains can be used in the pressing process, but their proportions should be as close as possible to the Fuller curve in order to achieve the most favorable results.

Claims (2)

PATENT APPEAL-. i. Process for the production of shaped brick bodies, in particular hollow brick blocks, in which a clay or ceramic raw material in granule form using low pressures that is largely gentle on the deposition structure of the granules or clay grains. A molded body is pressed, according to patent 864675, characterized in that such raw material, which is not in the form of clay crumbs when excavating from the wall, is brought into the form of granules by mechanical preparation while largely preserving the natural deposit structure in the individual clay grains . 2. The method according to claim T, characterized in that the. Mechanical preparation of the material by crushing machines and / or vibrating sieves takes place in such a way that the dimensions of the resulting clay crumbs or clay grains and their mixing ratio correspond approximately to the Fuller curve known from concrete construction in analogous transfer of the scales. 3. The method according to claim i and 2, characterized in that the raw material, which contains foreign inclusions, is very hard or comes from inhomogeneous clay occurrences with very hard clay layers, is mechanically prepared by means of such machines, which the foreign inclusions and / or lumps of clay shatter hard layers of clay. 4. The method according to claim i to 3, characterized in that the moisture content is adjusted so that the edge zones ' of the clay grains or granules can plastically penetrate one another. 5. The method according to claim 4, characterized in that in a clay deposit that is too moist for the method and cannot be crumbled, the raw material prior to mechanical preparation by air drying of the excavated material or the like. Is dried. 6. The method according to claim 4, characterized in that in a crumbly, too moist raw material drying during or after the mechanical Vorbe . preparation of the material is carried out. 7. The method according to claim 4, characterized in that, in the case of a crumbly, excessively moist raw material, the gems are mixed in during or after the mechanical preparation, particularly tru # ckew clay grains, preferably in the form of dust. 8. The method according to claim4, characterized in that a too dry raw material, for. B. by spraying, before, during or after the mechanical preparation, is moistened in such a way that the edges of the clay grains become plasüsch. G. A method according to claim 4, characterized in that if the raw material is too dry, especially if the grain is hard, such as slate, part of the clay grains, especially the fine grains of grain, is plasticized and / or fine grains of a very moist clay are added. Documents considered: German Patent No. 428 853; British Patent Specification Nos. 394667, 627264.