EP3479980A1 - Method for surfacing a rock and sedimentary stone - Google Patents

Abstract

The present invention relates to a method of surfacing a rock having at least one surface to be treated in a device comprising a flame unit followed by a water jet treatment unit, comprising: feeding said rock onto a conveyor belt towards said flaming unit which comprises at least one flaming head provided with at least two flaming nozzles fed with fuel and with oxidant and facing said at least one surface to be flamed. treat flaming said at least one surface by means of said flaming head supplying said rock towards said water jet treatment unit applying at least one jet of water at high pressure by means of said water jet head towards said at least one surface, - Obtaining a rock anthracite gray whole color.

Description

The present invention relates to a method of surfacing a rock, preferably a fossiliferous calcified carbonate-crinoid sedimentary rock.

In general, a calcareous fossiliferous to crinoid carbonate sedimentary rock, whether treated or not, shaped as an article or not, may also be referred to as "blue stone".

Blue stones are widely used as a noble material, for example to form window sills, terrace slabs or facade cladding. The blue stone is defined as a fossiliferous limestone with crinoids according to the nomenclature of PTV 844 - level 5 precision, registered at the Belgian Institute for Standardization (IBN) on 23 September 2005 - (NBN EN 12670). This compact limestone of gray-blue hue and stratigraphic Upper Tournaisian age also meets the descriptions written in the NIT 220 "The Belgian Blue Stone called Little Granite of Geological Age Tournaisien" and NIT 228 "Natural Stones" of the CSTC (Center Scientific and Technical Building, Belgium). These stones also correspond to the name of limestone carbonate fossiliferous to crinoid sedimentary rocks.

The document WO 993 22 62 refers to an abrasive surface treatment method of stone slab. This teaching proposes to apply a treatment by jets of water to provide a final product with an improved external aspect compared to a product obtained by application of a flame.

According to this document, the use of a treatment with flaming is restrictive and does not provide a quality product with an improved appearance, especially because of the heat shock resulting from such treatment.

In addition, it has become apparent that the current treatments for giving the blue stones a dark hue, preferably anthracite gray make the surface of the blue stones particularly smooth. In fact, the surfacing treatments currently applied to give the blue stones a dark hue are essentially based on polishing, which inevitably makes the treated stones particularly smooth. However, these smooth surfaces can be dangerous when the stones are used as slabs or pavers placed outside, to achieve for example, a door sill, a path or a terrace. Indeed, because of their smooth surface, these stones can be particularly slippery, this phenomenon being further accentuated during precipitation during which, the stones are likely to be covered with a film of water, the surfaces being even more slippery and therefore all the more dangerous for people putting their foot on it.

Another disadvantage of current treatment processes is the lifetime of the product obtained, as regards the maintenance of a dark shade over time. When stone slabs are laid outdoors, they tend to lose their dark hue over time and become more lighter, which makes them much less aesthetic and requires replacement. This lightening phenomenon is observed even when a polishing pretreatment to make the darker blue stones has been applied. This is partly due to the pollution, weather and stress that the surface of the blue stones may have when placed outdoors.

There is a real need to provide a more efficient, even more cost effective, rock surface treatment process that increases the life of the final product. In addition, there is also a need to provide a method suitable for forming a non-slip surface, while ensuring that the dark shade of the rock is preserved over time, particularly when the rock is exposed to the outside environment.

• amenée de ladite roche sur une bande transporteuse, présentant une vitesse de déplacement prédéterminée selon un plan A, en direction de ladite unité de flammage qui comporte au moins une tête de flammage munie d'au moins deux buses de flammage, de préférence au moins 3 buses de flammage, alimentées en combustible et en comburant et faisant face à ladite au moins une surface à traiter, ladite tête de flammage étant agencée pour être orientée dans le sens de déplacement de ladite bande transporteuse par inclinaison selon un angle prédéfini,
• flammage de ladite au moins une surface au moyen de ladite tête de flammage conférant une teinte foncée et mat à ladite au moins une surface,
• amenée de ladite roche présentant ladite au moins une surface traitée par flamme en direction de ladite unité de traitement par jet d'eau qui comporte une tête à jet d'eau munie de plusieurs ouvertures,
• application d'au moins un jet d'eau à haute pression au moyen de ladite tête à jet d'eau en direction de ladite au moins une surface préalablement traitée par flamme pour former sur ladite au moins une surface de ladite roche une structure rugueuse, et
• obtention d'une roche de teinte d'ensemble gris anthracite, constellée de plusieurs fragments fossiles, de cristaux, de préférence de type calcite, dont les plans de clivage scintillent à la lumière et présentant un relief de surface antidérapante.

To solve these problems, it is provided according to the present invention a method of surfacing a rock, preferably a rock crinoid fossiliferous carbonate calcareous sediment having at least one surface to be treated in a surface treatment device comprising a flaming unit followed by a water jet treatment unit, said process comprising successively the following steps:

• feeding said rock onto a conveyor belt, having a predetermined movement speed along a plane A, towards said flaming unit which comprises at least one flaming head provided with at least two flaming nozzles, preferably at least 3 flaming nozzles, supplied with fuel and with oxidant and facing said at least one surface to be treated, said flaming head being arranged to be oriented in the direction of movement of said conveyor belt by inclination at a predefined angle,
• flaming said at least one surface by means of said flaming head imparting a dark and matte shade to said at least one surface,
• supplying said rock having said at least one flame-treated surface to said water jet treatment unit which comprises a water jet head provided with a plurality of openings,
• applying at least one high-pressure water jet by means of said water-jet head towards said at least one previously flame-treated surface to form on said at least one surface of said rock a rough structure, and
• obtaining a rock of anthracite gray overall color, studded with several fossil fragments, crystals, preferably of calcite type, whose cleavage planes glitter in the light and having a non-slip surface relief.

The method according to the invention is more cost effective than known treatment methods since it can be applied to rocks that are normally discarded. This is totally surprising considering the state of the art. Indeed, it is known that some rocks, as For example, blue stones have defects within them, such as, for example, charcoal veins, generally black in color. In addition to being unsightly, these defects represent points of weakness that can reduce the resistance of the blue stone to external constraints. Typically, these types of rock are generally not valued and are therefore decommissioned because they do not have a sufficient level of quality for rock breeders, especially for slices.

For these reasons, these rocks with veins are therefore discarded by the rock operators because their use can not be valued, which generates a serious loss of income for the operators of these rocks.

However, the method according to the invention makes it possible to valorize this product, normally discarded, by the application of a first flaming step followed by a water jet treatment step.

Indeed, the method according to the invention has the effect of etching the surface by removing the rock parts may have weak points, without affecting the rock deep. It results in particular that the resistance of the treated rock is reinforced. This process therefore makes it possible to reduce the quantity of discarded rocks after extraction in quarries. Rock and especially blue stone operators can thus commercialize a greater quantity of rocks, which increases the value of this product, and makes the process of quarrying rock profitable.

In addition, the method according to the invention makes it possible to provide a rock of which at least one of the surfaces, the treated surface, has a dark shade, preferably anthracite gray. This shade is particularly sought after by the consumer.

In this regard, it has been found that the process according to the invention makes it possible to increase the duration of the final product obtained, since the preservation of the dark shade is guaranteed over time. It has been demonstrated that the dark shade of rock, for example blue stones treated by the process according to the invention, is maintained significantly more for a long time, even in external conditions, with respect to similar rocks, for which another surfacing method (polishing for example) has been applied for the same purpose.

Finally, the fact of applying a flaming step and then a water jet treatment makes it possible to impart a certain roughness to the treated surface of the rock, which gives it anti-slip properties.

It has also been observed that the surfacing treatment according to the invention makes it possible to obtain blue stones whose surface is studded with several fossil fragments, of crystals, preferably of the calcite type, whose cleavage planes sparkle in the light. This flicker effect in the light is particularly unexpected.

Preferably, said flaming step is accompanied by an addition of a quantity of water, preferably cold, on said at least one surface of said rock to cause a temperature shock.

It has been observed that the application of water, preferably cold on the surface of the treated rock, causes a peeling phenomenon of the surface. This flaking comes from the thermal shock created by the application of water after the passage of the flame during the flaming step. This peeling allows both to provide a certain roughness on the surface of the stone and to further reduce the presence of defects such as charcoal veins on the surface of the treated rock. This phenomenon is particularly surprising since it is known from the state of the art that thermal shocks must be avoided at all costs in order to preserve the resistance of the rock.

Preferably, said flaming head is further arranged to be displaced transversely with respect to the direction of movement of said conveyor belt at a translation speed of between 45 and 120 cm / min, preferably between 50 and 100 cm / min, plus preferably between 65 and 90 cm / min, more preferably still equal to 75 cm / min.

The transverse displacement of the flaming head makes it possible to treat all of said at least one surface in a substantially homogeneous manner.

Preferably, said openings of said water jet head are rotatably mounted and each have a rotation speed of between 300 rpm and 700 rpm, preferably between 400 rpm and 600 rpm, more preferably between 450 and 550 rpm.

This makes it possible to choose the most appropriate rotational speed to provide a surface rendering as desired.

Advantageously, said speed of said conveyor belt is between 50 cm / min and 150 cm / min, preferably between 100 cm / min and 110 cm / min.

This allows to manage the exposure time or treatment of said rock in each unit, in this case flaming and water jet treatment.

Preferably, said rock is in the form of a slice obtained by cutting said rock, said slice having a thickness of between 1 and 30 cm, preferably ranging from 1.5 cm to 20 cm, more preferably between 3 and 10 cm.

It is preferable to opt for a slice with a thickness included in one of the abovementioned ranges to be able to provide a final product that can be used in various fields of application.

Preferably, said flaming head is inclined in the direction of movement of said conveyor belt at an angle of between 0 and 75 °, preferably between 10 and 45 °, more preferably between 15 and 35 °, defined with respect to an axis. perpendicular to said plane A.

This makes it possible to treat the at least one surface with a flame angle that can give a very precise surface structure. The goal is to provide a non-slip end product.

Advantageously, each nozzle of said flaming head has a distal end located at a distance from said at least one surface of said rock, said distance being between 25 and 35 mm, preferably between 29 and 31 mm.

Preferably, said flaming head is provided with 3 nozzles arranged to form the edges of a triangle.

Advantageously, each nozzle of said flame head has an opening diameter of between 3.5 and 4.5 mm, preferably between 3.8 and 4 mm.

Preferably, each nozzle of said flaming head has a length of between 70 and 90 mm, preferably between 75 and 85 mm, more preferably between 79 and 81 mm.

Advantageously, the flaming step is carried out at a temperature between 0 ° C. and 4000 ° C., preferably between 1000 ° C. and 3000 ° C., even more preferably between 1000 and 1500 ° C.

Preferably, the method according to the invention comprises a step of feeding said nozzles with a propylene / oxygen mixture, preferably in a ratio of 1.1: 5 (expressed in volume).

Other embodiments of the process according to the invention are indicated in the appended claims.

The present invention also relates to a crinoid fossiliferous carbonate calcareous sedimentary stone obtained by the process according to the present invention, characterized in that it has a coefficient of friction of at least 0.71 and a slip angle of at least 35. ° evaluated according to DIN 51130, which corresponds to a slip resistance class R13.

Other embodiments of the stone obtained directly by the process according to the invention are indicated in the appended claims.

The present invention also relates to a crinoid fossiliferous carbonate calcareous sedimentary stone obtainable according to any one of the preceding claims of an overall anthracite gray color, constellated with several fossil fragments, with crystalline crystals. calcite whose cleavage planes are scintillated by light and have a non-slip surface relief, obtained by the application of a flame followed by a jet of water at high pressure.

Preferably, the abovementioned stone also has a colorimetric measurement variation measured according to DIN 6174, less than or equal to 1, after having been exposed to outside conditions for a period of two months.

The variation in colorimetric measurement is determined by subtracting the colorimetric value indicated after 2 months of exposure in an external environment to that taken at time zero, in this case before exposure in an external environment. The subtraction of these two values being less than or equal to 1.

Advantageously, said stone has a surface relief of between 0 and 1 mm, preferably between 0.1 and 0.8 mm.

Other embodiments of the stone obtainable according to the invention are indicated in the appended claims.

A fossiliferous crinoid limestone carbonate sedimentary rock was extracted as a block within a quarry then placed in a cutting unit where the rock is recovered as a slice having a thickness between 1.5 and 20 cm.

Thus, several slices are recovered and need to be visually evaluated by experts in order to classify them according to their degree of quality.

Slices that have the lowest degree of quality and should normally be discarded are stored for processing and thus valued using the method of the present invention. Such slices have dark veins or black tint.

In the method according to the invention, these slices having veins can be placed in the treatment device according to the invention which comprises two units. The first flaming unit comprises a flaming head provided with three nozzles arranged relative to each other so as to constitute the vertices of a triangle. The second unit is a water jet treatment area. The combination of these two treatments constitutes the heart of the present invention.

In practice, the wafer is fed on a conveyor belt which has a movement speed of between 50 cm / minute and 150 cm / minute along a plane A, towards said flame unit. The flame head is supplied with fuel and oxidant so that the nozzles can generate a flame that faces the surface of the wafer. In addition, the flaming head has previously been manipulated to be inclined in the direction of movement of said conveyor belt by between 15 and 45 °, relative to an axis perpendicular to the plane A.

In addition, the flaming head moves in translation, transversely to the plane A (in the direction of the width of the slice) to scan the slice across its width. In this way, the flame treatment is carried out homogeneously, that is to say over the entire surface to be treated, at a temperature of between 1000 and 4000 ° C.

During this flaming step, it may be accompanied by an addition of water which is injected into the surface of the flame-treated wafer in order to form a peeling of the surface.

After passing through the flaming unit, the wafer is fed to the water jet treatment unit which has a water jet head with a plurality of openings. This step is carried out with a water jet pressure of between 500 and 2000 bar, preferably about 1000 bar to give the surface of the wafer roughness.

This makes it possible to obtain an anthracite gray colored shade rock, studded with several fossil fragments, crystals, preferably of calcite type, whose cleavage planes are scintillated by light and having a non-slip surface relief.

Preferably, said openings of said water jet head are each formed of a water jet nozzle and are mounted on a tray. Preferably, said plate comprises 20 bushings.

Preferably, said plate has a rotation speed of between 300 rpm and 700 rpm, preferably between 400 rpm and 600 rpm, more preferably between 450 and 550 rpm.

Advantageously, each nozzle of said flaming head has a distal end located at a distance from said at least one surface of said rock, said distance being between 25 and 35 mm, preferably between 29 and 31 mm.

In particular, said flaming head is provided with 3 nozzles arranged to form the edges of a triangle.

Advantageously, each nozzle of said flaming head has an opening diameter of between 3.5 and 4.5 mm, preferably between 3.8 and 4 mm.

In addition, each nozzle of said flaming head may have a length of between 70 and 90 mm, preferably between 75 and 85 mm, more preferably between 79 and 81 mm.

Other features, details and advantages of the invention will become apparent from the description given below, without limitation and with reference to the accompanying drawings.

In the context of the present invention, the determination of a colorimetric value can be carried out using a spectrophotometer, for example a MiniScan® EZ brand supplied by HunterLab.

The principle of measurement is to determine the color on a scale from 0 to 100, where 0 is black and 100 is white.

In the context of the present invention, the surface relief between 0 and 1 mm, preferably between 0.1 and 0.8 mm, is determined using a profile probe having graduations, such as for example the Profilmeister. provided by Staba.

• La figure 1 est une vue en perspective de l'unité de flammage du dispositif de traitement de surface selon l'invention en présence d'une tranche de roche dont la surface doit être traitée.
• La figure 2 est une vue en coupe transversale de la tête de flammage selon l'invention.
• La figure 1 représente une unité de flammage 3 selon l'invention comprenant une tête de flammage 5 et une bande transporteuse 4 convoyant une roche 1 coupée en tranche d'une certaine épaisseur 7 dans la direction x.

With this tool, it is possible to determine the surface relief of the rock in a precise way.

• The figure 1 is a perspective view of the flaming unit of the surface treatment device according to the invention in the presence of a slice of rock whose surface is to be treated.
• The figure 2 is a cross-sectional view of the flame head according to the invention.
• The figure 1 represents a flaming unit 3 according to the invention comprising a flaming head 5 and a conveyor belt 4 conveying a rock 1 cut into a slice of a certain thickness 7 in the x direction.

The flaming head 5 is inclined at a predetermined angle y defined with respect to a perpendicular axis B to said plane A and comprises three flaming nozzles 6 directed towards the surface 2 of the rock 1, to be treated.

The figure 2 is a cross-section through the 3 flaming nozzles 6 of the flaming head 5 arranged to form the vertices of a triangle.

Example 1

A fossiliferous crinoid limestone carbonate sedimentary rock was extracted as a block within a quarry and then sawn to form a 1.5 cm thick slice. The wafer is then fed into the surface treatment device.

The wafer is placed on a conveyor belt traveling at a speed of 105 cm / min and is first introduced into a flaming unit which is provided with a flame head having three nozzles arranged in a triangle, each having a diameter d opening of 3.98 mm and a length of 80 mm. The flaming nozzles are fed with a mixture of oxygen and propylene (5: 1.1, v / v) and generate a flame having a height of 30 mm towards the surface of the wafer in order to treat it. The flaming head is inclined relative to a plane perpendicular to said surface of said slice at an angle of 71 °. Of moreover, the flaming head is disposed at a distance of 30 mm from the surface of the treated slice.

During the flaming step, the flaming head translates at a speed of 75 cm / min in a direction perpendicular to the direction in which the wafer is conveyed by the conveyor belt. During the passage of the flame, tap water at about 10 ° C is applied to the surface of the rock by a jet of water.

The wafer is then conveyed by the conveyor belt to the water jet treatment unit. A water jet head having a series of nozzles generates at least one jet of water at a pressure of 1000 bar towards the surface of the wafer. During the water jet treatment step, the water jet head also translates at a speed of 40 cm / min in a direction perpendicular to the direction in which the wafer is conveyed by the conveyor belt. . In addition, the water jet head comprises a rotating plate comprising 20 nozzles forming as many openings from which water jets are directed towards the surface of the wafer. In addition, during processing, the turntable rotates at a speed of 500 rpm and is at a distance of 30 mm from the surface of the treated wafer.

At the end of treatment, the slice obtained after treatment has a deep anthracite gray hue and is studded with numerous fossil fragments, calcite crystals which have cleavage planes scintillating in the light. The wafer surface has a coefficient of friction of at least 0.71 and a slip angle of at least 35 ° evaluated according to DIN 51130, which corresponds to a slip resistance class R13. The measured colorimetric index, preferably according to DIN 6174, is 39.985 using a MiniScan® EZ spectrophotometer supplied by HunterLab. The chosen color scale has a value of zero for the color black and a value equal to 100 for the color white.

Comparative example

The conditions of Example 1 were reproduced except that a sanding step was carried out instead of flaming and jet of water.

The lifetimes (by measurement of colorimetry) of a fossiliferous crinoid carbonate calcareous sedimentary rock treated according to Example 1 and a crinoid fossiliferous carbonate calcareous sedimentary rock treated according to the comparative example were compared.

For this, two slabs have been placed close to each other outdoors, so that they both experience the same external conditions in terms of exposure to UV, rain, wind and Pollution.

Before external exposure, the treated surface of the slab according to Example 1 has a colorimetric value of 39.985 and a value of 40.240 after 2 months of exposure.

The treated surface of the wafer according to the comparative example has, before exposure, a colorimetric value of 24.751 and, after exposure for one month, a value of 30.506.

Claims (15)

Method for surfacing a rock (1), preferably a fossiliferous crinoid limestone carbonate sedimentary rock (1), having at least one surface (2) to be treated in a surface treatment device comprising a flaming unit (3) followed by a water jet treatment unit, said process comprising successively the following steps: supplying said rock (1) on a conveyor belt (4), having a predetermined displacement speed (x) along a plane A, in the direction of said flaming unit (3) which comprises at least one flaming head (5); ) provided with at least two flaming nozzles (6), preferably at least 3 flaming nozzles (6), supplied with fuel and oxidant and facing said at least one surface (2) to be treated, said flaming head flaming (5) being arranged to be oriented in the direction of movement of said conveyor belt (4) by inclination at a predefined angle, flaming said at least one surface (2) by means of said flaming head (5) giving a dark and matte shade to said at least one surface (2), supplying said rock (1) having said at least one flame-treated surface (2) in the direction of said water jet treatment unit which comprises a water jet head provided with a plurality of openings, applying at least one high pressure water jet by means of said water jet head towards said at least one previously flame-treated surface (2) to form on said at least one surface (2) said rock (1) has a rough structure, and - Obtaining a rock with anthracite gray overall color, constellated with several fossil fragments, crystals, preferably of type calcite, whose cleavage planes are scintillated by light and have a non-slip surface relief. The method of claim 1, wherein said flaming step is continued by applying a quantity of water, preferably cold, to said at least one surface (2) of said rock (1) to cause a temperature shock. Method according to claim 1 or 2, wherein said flaming head (5) is further arranged to be displaced transversely with respect to the direction of movement of said conveyor belt (4) at a translation speed of between 45 and 120 cm / min, preferably between 50 and 100 cm / min, more preferably between 65 and 90 cm / min, more preferably still equal to 75 cm / min. A method according to any one of the preceding claims, wherein said apertures of said water jet head are rotatably mounted and each have a rotational speed of between 300 rpm and 700 rpm, preferably 400 revolutions / minute. minute and 600 rpm, more preferably between 450 and 550 rpm. Method according to any of the preceding claims, wherein said speed (x) of said conveyor belt (4) is between 50 cm / min and 150 cm / min, preferably between 100 cm / min and 110 cm / min. Method according to any one of the preceding claims, wherein said rock (1) is in the form of a slice obtained by cutting said rock (1), said slice having a thickness of between 1 and 30 cm, preferably ranging from 1.5 cm to 20 cm, more preferably between 3 and 10 cm. A method as claimed in any one of the preceding claims, wherein said flaming head (5) is inclined in the direction of movement of said conveyor belt (4) at an angle (y) of between 0 and 75 °, preferably between 10 ° and 75 °. and 45 °, more preferably between 15 and 35 °, defined with respect to an axis (B) perpendicular to said plane A. A method as claimed in any one of the preceding claims, wherein each nozzle (6) of said flame head (5) has a distal end located at a distance from said at least one surface (2) of said rock (1), said distance being between 25 and 35 mm, preferably between 29 and 31 mm. A method according to any one of the preceding claims, wherein said flaming head (5) is provided with 3 nozzles (6) arranged to form the edges of a triangle. Method according to any of the preceding claims, wherein each nozzle (6) of said flame head (5) has an opening diameter of between 3.5 and 4.5 mm, preferably between 3.8 and 4 mm. Process according to any one of the preceding claims, in which each nozzle (6) of said flaming head (5) has a length of between 70 and 90 mm, preferably between 75 and 85 mm, more preferably between 79 and 81 mm. . Process according to any one of the preceding claims, in which the flaming step is carried out at a temperature of between 0 ° C. and 4000 ° C., preferably between 1000 ° C. and 3000 ° C., even more preferably between 1000 ° C and 1500 ° C. Crinoid fossiliferous carbonate calcareous sedimentary stone obtained by the process according to any one of claims 1 to 12, characterized in that it has a coefficient of friction of at least 0.71 and an angle of slipperiness of at least 35 ° evaluated according to DIN 51130, which corresponds to a slip resistance class R13. Crinoid fossiliferous limestone carbonate sedimentary stone obtainable according to any one of the preceding claims of an overall anthracite gray color, constellated with several fossil fragments, with calcite crystals whose cleavage planes are scintillated by light and have a relief of anti-slip surface, obtained by the application of a flame followed by a jet of water at high pressure, and further having a colorimetric measurement variation, preferably measured according to DIN6174, less than or equal to 1, after having been exposed to outside conditions for a period of two months. Blue stone according to Claim 14, having a surface relief of between 0 and 1 mm, preferably between 0.1 and 0.8 mm.

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