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Title:
PROCESS OF TREATMENT OF LARGE CERAMIC SLABS
Document Type and Number:
WIPO Patent Application WO/2019/234528
Kind Code:
A1
Abstract:
A process of treatment of ceramic slabs, comprises the phases of preparing slabs made of ceramic material (CT) with dimensions equal to about 1 x 3 m, drying said slabs (CT); firing the slabs at a temperature of about 8000-1100°C, storing the slabs vertically on special supports similar to those already used in the glass industry, single or double inclined, or horizontally in a special storage unit (8), which may comprise wooden crates, or similar material, slightly larger than the fired size of the material; taking the stored slabs (CT) and decorating them by applying slip paints and/or glazes, firing the glazed slabs at a temperature ranging from 1100° to 1300°C.

Inventors:
BIANCHINI ALESSANDRO (IT)
BARANI DOMENICO (IT)
Application Number:
PCT/IB2019/054018
Publication Date:
December 12, 2019
Filing Date:
May 15, 2019
Export Citation:
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Assignee:
SITI B & T GROUP SPA (IT)
International Classes:
B28B11/04; B28B11/24; C04B41/86; G06Q50/04
Domestic Patent References:
WO2018007972A12018-01-11
WO2012137066A12012-10-11
WO2001024074A12001-04-05
Foreign References:
CN104591805A2015-05-06
JP2016193811A2016-11-17
EP2266769A12010-12-29
DE102005042456A12007-05-16
Attorney, Agent or Firm:
ZOLI, Filippo (IT)
Download PDF:
Claims:
CLAIMS

1) Process of treatment of ceramic slabs, comprising the following phases: preparing slabs made of ceramic material (CT) with dimensions ranging from lxl m to 1.6 x 3.6 m and thickness equal to about 5-12 mm, drying said slabs (CT),

firing said slabs at a temperature of about 8000-1100°C,

storing said slabs (CT),

taking said stored slabs (CT) and decorating them by applying slip paints and/or glazes,

firing said glazed slabs at a temperature ranging from 1100° to 1300°C.

2) Process according to claim 1, wherein said drying phase is carried out at a temperature of less than 250°C, or 200°C, or 150°C, in order to obtain a removal of the residual water from the slab.

3) Process according to claim 1 or 2, wherein said storage phase comprises a vertical and/or horizontal storage in wooden crates.

4) Process according to the preceding claim, wherein said vertical storage phase occurs on single or double inclination supports.

5) Process according to claim 3, wherein said horizontal storage phase occurs in a storage unit (8), which may comprise wooden crates, or similar material, slightly larger than the fired size of the slabs and overlapping a maximum of 6-8 slabs (CT), the maximum number being determined by the mechanical strength of the slabs themselves.

6) Process according to any of the preceding claims, wherein said decoration phase comprises the application of traditional and/or digital glazes.

7) Process according to any of the preceding claims, wherein said firing phase of glazed slabs comprises a firing phase at a temperature ranging from 1190°C to 1210°C.

8) Process according to any of the preceding claims, wherein before said drying phase, said slabs are pressed and trimmed.

9) Process according to any of the preceding claims, wherein said slabs are stored before being decorated, and are taken to be subjected to the subsequent decoration phase only after a specific order from customers was obtained, so as to produce decorated tiles only on demand.

Description:
PROCESS OF TREATMENT OF LARGE CERAMIC SLABS

Technical Field

The present invention relates to a process of treatment of large ceramic slabs. Background Art

Large decorated ceramic tiles, i.e. tiles larger than 1000x1000 mm, are usually produced using processes including, among other things, a single firing phase of the starting slab. These slabs are also decorated with slip paints and glazes. Description of the Invention

One object of the present invention is to provide a new process of treatment of large ceramic slabs or tiles.

One object of the present invention is to provide a new process of treatment of large ceramic slabs or tiles that is cheaper than the processes currently carried out.

Another object of the present invention is to provide a new process of treatment of large ceramic slabs or tiles that is more effective than the processes so far envisaged.

Another object of the present invention is to provide a new process of treatment of ceramic slabs or tiles that allows reducing storage costs.

Another object of the present invention is to provide a new process of treatment of ceramic slabs or tiles that allows eliminating the risk of producing finished slabs or tiles that remain unsold.

In accordance with one aspect of the invention, a process of treatment of ceramic slabs according to claim 1 is provided.

Dependent claims relate to preferred and advantageous embodiments of the invention.

Brief Description of the Drawings

Other characteristics and advantages of the invention will be more evident from the description of an embodiment of a plant for the realization of a process according to the present invention, illustrated as an indication in the attached Figure 1.

Embodiments of the Invention

In accordance with the present invention, a process is provided for the treatment of ceramic slabs CT, in particular large ceramic slabs, which first provides for the preparation of a ceramic slab with dimensions, width and length, ranging from 1 x 1 m to 1.6 x 3.6 m, for example equal to about 1x3 m.

The thickness of the starting slabs CT can be about 5-12 mm, possibly 5-10 or 6-8 mm.

These slabs CT are then pressed with the aid of presses able to guarantee the application of a pressure or pressing force of 400-450 Kg/cm 2 or about 39-44 MPa on a slab with a surface and thickness as indicated above, trimmed by means of high speed cutting discs and dried by means of horizontal dryers on one or more floors depending on the production output of the plant.

To do this, the slab CT or slabs CT can be processed in a plant 1 and arranged on a special conveying means of same, such as a conveyor belt 2a, by means of which the slabs CT are brought to a special pressing unit 3, trimming unit 4 and drying unit 5.

The pressing unit 3 and the trimming unit 4 4 are optional and may not be provided.

The trimming phase can be carried out in raw green, but also in raw dry.

The drying phase is preferably carried out quickly with drying cycles of less than 60 minutes, at a temperature of less than 250°C or 200°C or 150°C for example in fast roller machines, in order to obtain an almost total removal of the residual water from the slab.

In actual facts, the newly pressed large slab CT is dried to remove residual moisture so as to achieve a level of toughness which is adapted to withstand subsequent handling without incurring surface and structural defects.

Subsequently, the slab CT is subjected to a first firing/inertization process, e.g. in a first kiln 6, in which the slabs CT are fired at a temperature of about 8000- 1100°C, possibly 1050°C-1080°C and then stored, possibly by means of special storage devices, such as movement arms 7 for the slabs CT.

Basically, after rapid drying, the material or slab is sent directly to a first kiln 6 and the purpose of the first firing is the inertization of the medium or slab.

This thermal firing phase not only produces an effective degassing of the medium or slab CT from organic substances, but it also contributes to making the medium or slab CT itself tough and easy to handle, with the possibility of being stored in the warehouse.

The approximate firing cycle for a slab of 1000 x 3000 x 9 mm size can be 100 minutes.

Storage can take place vertically on special supports similar to those already used in the glass industry, single or double inclined, or horizontally in a special storage unit 8, which may comprise wooden crates, or similar material, slightly larger than the fired size of the material.

The storage unit 8 can allow the overlapping of a maximum of 6-8 units or supports or slabs CT, the maximum number being determined by the mechanical strength of the units themselves.

In this regard, during the first phases the material is transformed or chemically treated in order to reach mechanical strength and toughness that allow storing it stacked vertically and/or horizontally in special wooden crates, possibly with a single or double inclination.

After storage, the slabs are taken, e.g. from a stack of stored slabs TS and decorated in a glazing line by applying traditional slip paints and/or glazes. Due to the size of the slabs, mobile airbrush booths are used for wet glazing and shot blasting machines for dry glazing.

This phase can be carried out by taking the stored slabs CT by means of suitable picking means 9 and arranging these on a special second conveying means, such as a second conveyor belt 2b, and then transporting them to ceramic glazing lines or to a special decoration unit 10 of the plant 1.

During this phase, together with the glazes or slip paints, inks and protective agents can also be applied (traditional, such as those used in flexographic printing and/or digital machines, such as those used in inkjet printing machines). Since the medium or slab is already partially fired, the liquid decorations are quickly dried and breakage due to movement of the slab is prevented.

After glazing or decorating the slab, this is subjected to a second firing, which can be carried out in a roller kiln similar to that of the first firing, at a temperature ranging from 1100° to l300°C, preferably ranging from H90°C to !2lO°C, depending on the chemical nature of the base mixture or rather on the components of the slab mixture and their specific effective sintering temperature.

The times also vary depending on the final thickness of the material.

The second firing can be carried out more quickly since the slab has already been degassed from the organic substances present in the clays during the first firing.

The approximate cycle of second firing for a slab measuring 1000 x 3000 x 9 mm is about 90 minutes.

The second firing can be carried out in a second kiln 11 or also in the first kiln properly calibrated.

The slab CT is therefore ready to be finished by cutting so as to obtain a cut slab CCT, e.g. in a special cutting unit 12 in the various sizes ranging from the maximum to the various possible modular sub-sizes.

Smaller sizes up to 1200 x 1200 mm can be boxed as coupled tiles in a variable number depending on the size, while larger sizes can be stored vertically or in special large wooden or metal crates in a reduced number depending on the final weight/thickness.

Basically, a process according to the present invention involves firing large ceramic slabs (about 1 x 3 m) in two distinct phases.

The finished product will have the technical characteristics of porcelain stoneware, such as, e.g., the international Bla class with water absorption of less than 0.5%.

As it can be understood, thanks to a process according to the present invention, it is possible to store a neutral product or slab or otherwise still unprocessed and then, in fact, standard and decorate the same only after orders from customers were obtained, so as to produce tiles only on demand, exactly reflecting what is ordered by the end customers, completely eliminating the warehouse of finished products.

This clearly leads to significantly lower storage or warehouse costs and at the same time to a reduction in the risk of producing finished slabs or tiles that are not actually sold.

Changes and variations of the invention are possible within the scope of protection defined by the claims.