Aqueous mixture, reconstructed marble obtained therefrom and relative preparation method

Abstract

An aqueous mixture comprises a solid material, which in turn comprises lactic casein, sodium hydroxide, calcium hydroxide, marble sand, and water. The weight ratio between lactic casein and sodium hydroxide is comprised between 1:0.25 and 1:20. The weight ratio between lactic casein and calcium hydroxide is comprised between 1:0.1 and 1:10. The weight ratio between lactic casein and marble sand is comprised between 1:2 and 1:80.

Description

[0001] TITLE: "Aqueous mixture, reconstructed marble obtained therefrom and relative preparation method"

[0002] DESCRIPTION

[0003] Technical field

[0004] The present invention relates to an aqueous mixture. More in particular, the present invention is useful for the production of reconstructed marble. In particular, the reconstructed marble obtained by the present invention is applicable in the construction field, as a cladding, in particular as a thermal -acoustic insulating material, and in the design and artistic fields, as a coating or workable material. The reconstructed marble has characteristics of mechanical resistance, liquid resistance, heat resistance and sound insulation.

[0005] Description of the prior art

[0006] Marble is widely used in the field of construction, for example to make flooring, wall cladding or pillars. The marble is extracted from quarries. The most common extraction method is cutting with diamond wire.

[0007] US 1629854 A discloses a composition of reconstructed marble.

[0008] Problem of the prior art

[0009] The extraction of marble from quarries is a process which generates a considerable amount of waste material, called "quarry waste", intended as a material which is particularly homogeneous by chemical composition (mainly CaCCh), but extremely heterogeneous in size. In particular, the waste comprises both masses of considerable size and ultra-fine and nanometric powders.

[0010] Particulate matter with a size less than 60 pm, called marble slurry, is an environmental problem. In fact, this debris is easily transported by atmospheric agents into waterways. The marble slurry deposits in the riverbeds and banks of rivers, blocking the airways of fish and invertebrates, and burying the flora and algae, which are at the base of the food chain of aquatic life forms.

[0011] The marble slurry can be separated by decanting the washing waters of a small portion of the quarry waste generated. The product thus generated is still considered waste and destined for landfill.

[0012] The composition of known reconstructed marble, while benefiting from the reuse of marble waste, has some critical issues in the manufacturing methodology, such as poor environmental sustainability, making it necessary to search for an alternative solution.

[0013] SUMMARY OF THE INVENTION

[0014] In this context, the technical task underlying the present invention is to propose an aqueous mixture comprising waste materials.

[0015] In particular, it is an object of the present invention to provide an aqueous mixture for reconstructed marble which is more eco-sustainable.

[0016] The technical task mentioned, and the objects stated are substantially achieved by an aqueous mixture comprising the technical features set out in one or more of the appended claims.

[0017] The present invention allows to provide an aqueous mixture for reconstructed marble which allows to recover the waste material coming from the production of the marble, in particular marble slurry.

[0018] Advantageously, it is possible to obtain an aqueous mixture using valuable materials such as marble and at the same time reducing the amount of waste released into the environment. DETAILED DESCRIPTION

[0019] An aqueous mixture, in accordance with the present invention, comprises a solid material and water. The solid material in turn comprises lactic casein, sodium hydroxide, calcium hydroxide, preferably slaked lime, and marble sand.

[0020] The sodium hydroxide accelerates the suspension of the lactic casein in water.

[0021] Calcium hydroxide is a calcifier which speeds up the drying process, which will be illustrated below in the present disclosure.

[0022] Preferably, the marble sand has a variable granulometry. The granulometry is determined through a characteristic size, for example the diameter. Preferably, the marble sand has variable fractions of ultra-fine marble particles, with a characteristic size of less than 60 pm, fine particles, with a characteristic size comprised between 60 pm and 200 pm, medium particles, with a characteristic size comprised between 200 pm and 400 pm, and coarse particles with a characteristic size comprised between 400 pm and 1500 pm. An example of marble sand granulometry distribution is as follows: 40% coarse particles, 30% medium particles and 30% ultra-fine particles.

[0023] The weight ratio between lactic casein and sodium hydroxide is comprised between 1 :0.25 and 1 :20.

[0024] The weight ratio between lactic casein and calcium hydroxide is comprised between 1 :0.1 and 1 : 10.

[0025] The weight ratio between lactic casein and marble sand is comprised between 1 :2 and 1 :80.

[0026] In accordance with an embodiment, the aqueous mixture comprises urea. Advantageously, urea improves the stability of the aqueous mixture.

[0027] The weight ratio between lactic casein and water is comprised between 1 :8 and 1 :0.8.

[0028] In accordance with an embodiment, the aqueous mixture comprises sodium tetraborate. Advantageously, sodium tetraborate, in combination with urea, allows to stabilize the casein.

[0029] The weight ratio between lactic casein and sodium tetraborate is comprised between 1 :0.05 and 1 : 10.

[0030] The aqueous mixture according to the present invention is used to obtain reconstructed marble.

[0031] According to a first embodiment, the reconstructed marble is obtained by pouring the aqueous mixture into a mould, pressing and drying at a temperature comprised between 15°C and 45°C for a time interval comprised between 4 hours and 72 hours.

[0032] In accordance with a second embodiment, the reconstructed marble is obtained by modelling or pouring and drying the modelled aqueous mixture at a temperature comprised between 15 and 45°C for a time interval comprised between 24 hours and 7 days.

[0033] According to a third embodiment, the reconstructed marble is obtained by drying the aqueous mixture at a temperature comprised between 15°C and 45°C for a time interval comprised between 24 hours and 7 days.

[0034] Preferably, a method for preparing reconstructed marble comprises a first step of preparing the aqueous mixture. The method for preparing reconstructed marble comprises a second step of pouring the aqueous mixture into a mould and pressing the aqueous mixture in the mould. The method for preparing reconstructed marble comprises a third step of exposing the aqueous mixture to air, at a temperature comprised between 15°C and 45°C, for a time interval comprised between 4 hours and 72 hours.

[0035] Still preferably, a method for preparing reconstructed marble comprises a first step of preparing the aqueous mixture. The method for preparing reconstructed marble comprises a second step of modelling or pouring the aqueous mixture into a mould. The method for preparing reconstructed marble comprises a third step of exposing the modelled or poured aqueous mixture to a temperature comprised between 15°C and 45°C for a time interval comprised between 24 hours and 7 days.

[0036] Preferably, the step of preparing the aqueous mixture comprises a sub step of providing a solid material comprising lactic casein, sodium hydroxide, calcium hydroxide and marble sand and a substep of providing water.

[0037] Preferably, the step of preparing the aqueous mixture comprises a sub step of making a solution with water and sodium hydroxide.

[0038] Preferably, the step of preparing the aqueous mixture comprises a further substep of adding lactic casein to the sodium hydroxide solution.

[0039] Preferably, the step of preparing the aqueous mixture comprises a subsequent substep of adding calcium hydroxide to the solution of sodium hydroxide and casein.

[0040] Preferably, the step of preparing the aqueous mixture comprises a further substep of adding marble sand.

[0041] Preferably, a method for preparing reconstructed marble comprises a first step of preparing the aqueous mixture. Preferably, the aqueous mixture comprises urea and sodium tetraborate. The method comprises a second step of exposing the aqueous mixture to air, at a temperature comprised between 15°C and 45°C, for a time interval comprised between 24 hours and 7 days.

[0042] The step of preparing the aqueous mixture comprises a step of providing a solid material, comprising lactic casein, sodium hydroxide, sodium tetraborate, calcium hydroxide, marble sand, urea, sodium tetraborate, and water.

[0043] The step of preparing the aqueous mixture comprises a further substep of making a solution with water, sodium hydroxide and sodium tetraborate.

[0044] Thereafter, the step of preparing the aqueous mixture comprises a sub step of adding lactic casein to the solution of sodium hydroxide and sodium tetraborate.

[0045] The step of preparing the aqueous mixture comprises a subsequent step of adding calcium hydroxide to the solution of sodium hydroxide and sodium tetraborate.

[0046] The step of preparing the aqueous mixture comprises a step of adding marble sand.

[0047] According to a first example of embodiment, the aqueous mixture comprises a solid material and water. The solid material in turn comprises lactic casein, sodium hydroxide, calcium hydroxide, preferably slaked lime, and marble sand.

[0048] According to this first example, the weight ratio between lactic casein and sodium hydroxide is equal to 1 :5. Furthermore, the weight ratio between lactic casein and calcium hydroxide is equal to 1 :3. The weight ratio between lactic casein and marble sand is equal to 1 :35.

[0049] According to such a first example, the aqueous mixture thus obtained is used to obtain reconstructed marble. The aqueous mixture is poured into a mould. Thereafter, the aqueous mixture is pressed in the mould. Preferably, the aqueous mixture in the mould is pressed by applying a pressure of up to 400 kg / cm2.

[0050] Furthermore, the pressed aqueous mixture is dried at a temperature comprised between 15°C and 45°C for a time interval comprised between 4 hours and 72 hours. Preferably, the drying time interval is proportional to a thickness of the pressed aqueous mixture.

[0051] A method for preparing reconstructed marble in accordance with the first example will now be disclosed.

[0052] The method includes a first step of preparing the aqueous mixture. Such a step includes further substeps.

[0053] In particular, the method includes a first substep of providing a solid material comprising lactic casein, sodium hydroxide, calcium hydroxide and marble sand. Preferably, the method includes providing slaked lime.

[0054] The method includes a second substep of providing water.

[0055] The method includes a third substep of making a solution with water and sodium hydroxide. Preferably, the method includes heating the solution to a temperature comprised between 40°C and 50°C. Preferably, the method includes mechanically stirring the sodium hydroxide solution.

[0056] The method includes further substeps of adding lactic casein to the sodium hydroxide solution, adding calcium hydroxide to the solution of sodium hydroxide and casein, and adding marble sand.

[0057] Preferably, the method includes adding lactic casein and calcium hydroxide until completely dissolved.

[0058] Once the aqueous mixture is obtained, the method includes a further step of pouring the aqueous mixture into a mould. Thereafter, the method includes a step of pressing the aqueous mixture into the mould. Lastly, the method includes a step of exposing the aqueous mixture to air, at a temperature comprised between 15°C and 45°C, for a time interval comprised between 4 hours and 72 hours.

[0059] Preferably, in accordance with the method for preparing reconstructed marble, it is possible to obtain pressed slabs, for example.

[0060] According to a second example of embodiment, the aqueous mixture comprises a solid material and water. The solid material in turn comprises lactic casein, sodium hydroxide, calcium hydroxide, preferably slaked lime, and marble sand.

[0061] In accordance with this second example, the weight ratio between lactic casein to sodium hydroxide is equal to 1 : 10.

[0062] Preferably, the weight ratio between lactic casein and calcium hydroxide is equal to 1 :4.

[0063] Preferably, the weight ratio between lactic casein and marble sand is equal to 1 :40.

[0064] According to such a second example, the aqueous mixture thus obtained is used to obtain reconstructed marble. The aqueous mixture is poured into a mould or modelled.

[0065] Furthermore, the pressed aqueous mixture is dried at a temperature comprised between 15°C and 45°C for a time interval comprised between 24 hours and 7 days. Preferably, the drying time interval is proportional to a thickness of the poured or modelled aqueous mixture.

[0066] A method for preparing reconstructed marble in accordance with the second example will now be disclosed.

[0067] The method includes a first step of preparing the aqueous mixture. Such a step includes further substeps.

[0068] In particular, the method includes a first substep of providing a solid material comprising lactic casein, sodium hydroxide, calcium hydroxide and marble sand. Preferably, the method includes providing slaked lime.

[0069] The method includes a second substep of providing water.

[0070] The method includes a third substep of making a solution with water and sodium hydroxide. Preferably, the method includes heating the solution to a temperature comprised between 40°C and 50°C. Preferably, the method includes mechanically stirring the sodium hydroxide solution.

[0071] The method includes further substeps of adding lactic casein to the sodium hydroxide solution, adding calcium hydroxide to the solution of sodium hydroxide and casein, and adding marble sand.

[0072] Preferably, the method includes adding lactic casein and calcium hydroxide until completely dissolved.

[0073] Once the aqueous mixture is obtained, the method includes a further step of pouring the aqueous mixture into a mould or modelling the aqueous mixture. Lastly, the method includes a step of exposing the aqueous mixture to air, at a temperature comprised between 15°C and 45°C, for a time interval comprised between 24 hours and 7 days.

[0074] According to a third example of embodiment, the aqueous mixture comprises a solid material and water. The solid material in turn comprises lactic casein, sodium hydroxide, calcium hydroxide, preferably slaked lime, marble sand, urea and sodium tetraborate.

[0075] According to this third example, the weight ratio between lactic casein and sodium hydroxide is equal to 1 : 10.

[0076] Preferably, the weight ratio between lactic casein and calcium hydroxide is equal to 1 :2.5.

[0077] Preferably, the weight ratio between lactic casein and marble sand is equal to 1 :22.5.

[0078] Preferably, the weight ratio between lactic casein and urea is equal to 2: 1.

[0079] Preferably, the weight ratio between lactic casein and sodium tetraborate is 1 : 1.

[0080] According to such a third example, the aqueous mixture thus obtained is used to obtain reconstructed marble for 3D printing. The aqueous mixture is exposed to air, at a temperature comprised between 15°C and 45°C, for a time interval comprised between 24 hours and 7 days.

[0081] A method for preparing reconstructed marble in accordance with the third example will now be disclosed.

[0082] The method includes a first step of preparing the aqueous mixture. Such a step includes further substeps.

[0083] In particular, the method includes a first substep of providing a solid material comprising lactic casein, sodium hydroxide, calcium hydroxide and marble sand. Preferably, the method includes providing slaked lime.

[0084] The method includes a second substep of providing water.

[0085] The method includes a third substep of making a solution with water and sodium hydroxide. Preferably, the method includes heating the solution to a temperature comprised between 40°C and 50°C. Preferably, the method includes mechanically stirring the sodium hydroxide solution.

[0086] The method includes further substeps of adding lactic casein to the sodium hydroxide solution, adding calcium hydroxide and urea to the solution of sodium hydroxide and casein, and adding marble sand. Preferably, the method includes adding lactic casein, urea and calcium hydroxide until completely dissolved.

[0087] Preferably, the method includes adjusting the rheological properties of the aqueous mixture, as a function of the 3D printer to be used.

[0088] Once the aqueous mixture is obtained, the method includes a further step of exposing the aqueous mixture to air, at a temperature comprised between 15°C and 45°C, for a time interval comprised between 24 hours and 7 days.

Claims

CLAIMS1. Aqueous mixture comprising: a) a solid material, in turn comprising:• lactic casein,• sodium hydroxide,• calcium hydroxide,• marble sand, b) water, wherein- the weight ratio between lactic casein and sodium hydroxide is comprised between 1 :0.25 and 1 :20,- the weight ratio between lactic casein and calcium hydroxide is comprised between 1 :0.1 and 1 : 10,- the weight ratio between lactic casein and marble sand is comprised between 1 :2 and 1 :80.

2. Aqueous mixture according to claim 1 comprising urea, the weight ratio between lactic casein and urea being comprised between 1 :8 and 1 :0.8.

3. Aqueous mixture according to claim 1 or 2 comprising sodium tetraborate, the weight ratio between lactic casein and sodium tetraborate being comprised between 1 :0.05 and 1 : 10.

4. Reconstructed marble obtained by pouring the aqueous mixture, according to claim 1, into a mould, pressing and drying at a temperature comprised between 15°C and 45°C the pressed aqueous mixture for a time interval comprised between 4 hours and72 hours.

5. Reconstructed marble obtained by modelling or pouring the aqueous mixture, according to claim 1, and drying the modelled aqueous mixture at a temperature comprised between 15 and 45°C for a time interval comprised between 24 hours and 7 days.

6. Reconstructed marble obtained by drying the aqueous mixture, according to claims 2 and 3, at a temperature comprised between 15°C and 45°C for a time interval comprised between 24 hours and 7 days.

7. Method for preparing reconstructed marble, comprising the steps of:- preparing the aqueous mixture according to claim 1,- pouring the aqueous mixture into a mould,- pressing the aqueous mixture in the mould,- exposing the aqueous mixture to air, at a temperature comprised between 15°C and 45°C, for a time interval comprised between 4 hours and 72 hours.

8. Method for preparing reconstructed marble, comprising the steps of:- preparing the aqueous mixture according to claim 1,- modelling or pouring the aqueous mixture into a mould,- exposing the modelled or poured aqueous mixture to a temperature comprised between 15°C and 45°C for a time interval comprised between 24 hours and 7 days.

9. Method for preparing reconstructed marble according to claim 7 or 8, wherein the step of preparing the aqueous mixture comprises the following substeps:- providing a solid material comprising lactic casein, sodium hydroxide, calcium hydroxide and marble sand,- providing water,- making a solution with water and sodium hydroxide,- adding lactic casein to the sodium hydroxide solution,- adding calcium hydroxide to the solution of sodium hydroxide and casein,- adding marble sand.

10. Method for preparing reconstructed marble, comprising the steps of:- preparing the aqueous mixture according to claims 2 and 3,- exposing the aqueous mixture to air, at a temperature comprised between 15°C and 45°C, for a time interval comprised between 24 hours and 7 days.

11. The method for preparing reconstructed marble according to claim 10, wherein the step of preparing the aqueous mixture comprises the following substeps:- providing a solid material comprising lactic casein, sodium hydroxide, sodium tetraborate, calcium hydroxide, marble sand,- providing water,- making a solution with water, sodium hydroxide and sodium tetraborate,- adding lactic casein to the solution of sodium hydroxide and sodium tetraborate,- adding calcium hydroxide to the solution of sodium hydroxide and sodium tetraborate,- adding marble sand.