IT201600082173A1 - POLYMERIZABLE MIXTURE, PRODUCTION PROCESS AND 3D PRINTING DEVICE FOR THE PRODUCTION OF A MANUFACTURE IN A GEOPOLYMERIC COMPOSITE MATERIAL, AND GEOPOLYMERIC COMPOSITE MATERIAL - Google Patents

Description

CURABLE BLEND, PRODUCTION PROCESS AND 3D PRINTING DEVICE FOR THE PRODUCTION OF AN ARTIFACT IN A GEOPOLIM ERIC COMPOSITE MATERIAL, AND GEOPOLIM ERICO COMPOSITE MATERIAL

DESCRIPTION OF THE INVENTION

The invention relates to the field of geopolymer composite materials. This sector includes: such materials, the manufactured articles in said materials, the polymerizable mixtures which can be used to realize said materials, and the production processes and the equipment for the production of said manufactured articles.

Geopolymer composite materials include a geopolymer and inert materials, homogeneously dispersed and incorporated into the geopolymer. By geopolymer we mean a synthetic aluminosilicate material with different degrees of crystallinity, obtained by reaction of an aluminum silicate powder (typically an activated clay, i.e. artificially or naturally calcined, in which case pozzolan is used, having a silica content and alumina higher than 80% (S1O2 + AI2O3> 80% weight) with an aqueous solution of hydroxides or with an aqueous solution containing alkaline hydroxides and silicates. This reaction is a polymerization reaction, more specifically a polycondensation which gives rise to a inorganic polymer Geopolymers can be considered “ceramics” consolidated by alkaline reaction and not by thermal sintering as for common ceramics.

To obtain the geopolymeric composite materials, the inert materials are mixed with said powder and said aqueous solution and, obviously, they do not take part in the polycondensation reaction and there are no unwanted reactions between them and the geopolymer. They include fillers, and optionally additives, which can be used for the production of ceramics, which are chosen on the basis of the characteristics (mechanical, thermal, aesthetic, eco) that are to be given to the geopolymeric composite material to be produced.

Usually, geopolymer composite materials are used for the production of products that can be used in civil construction, typically for casting. The forming of casting products involves waste of raw materials, long production times, and the tooling of the molds, which are subjected to considerable wear. The materials currently used to make containers for the production and storage of food and / or drinks with a relative degree of acidity, such as oil, beer, wine and vinegar, are classical ceramics (where classical means ceramics subjected to sintering high temperature thermal, typically between 800 - 1700 ° C), concrete, steel, fiberglass, and wood. Typically these containers are jars or barrels, or barrels typically of about 250 liters, called "barriques". The latter are mostly used for the aging of fine wines and / or liqueurs.

The classic ceramic, cement or fiberglass jars are made with a high incidence of manual labor and therefore have relatively long production times and the need to resort to cooking and / or manual finishing processes. Furthermore, classical ceramics require the application of glass-like finishes with high contents of heavy metals, typically lead, cadmium, selenium, which can be released to the liquids contained. The cement also has a limited resistance to the acidity of said liquids contained with the possibility of releasing components of the cement itself. The fiberglass itself is not completely inert to the acidity of said foods and / or beverages, resulting in the disadvantage of potential contamination of the liquids contained. As for the steel containers, the relative production involves a high cost, and a considerable use of energy. Furthermore, steel is susceptible to passivation and / or oxidation phenomena with the release of toxic and / or harmful substances to the liquids contained. Unfortunately, wood is an organic material, therefore it is subject to organic deterioration and can be a source of bacterial contamination and / or bacterial growth phenomena with the conferment of unwanted organoleptic characteristics to the liquids contained in the relative containers.

The invention aims to overcome the drawbacks of the aforementioned containers for production and storage and the related materials with which they were made. In particular, an object of the invention is to allow the production and storage of foods and / or drinks having a relative degree of acidity, such as oil, beer, wine and vinegar, in inert containers, which are easy, fast and economical to make, which involve : a low energy expenditure and a corresponding low C02 emission; of production waste and almost zero waste, and that are biocompatible, recyclable and that do not involve particular safety risks both in their production and in their use.

The aforementioned purposes and objectives have been achieved by means of a polymerizable mixture in accordance with the content of claim 1, a production process and 3D printing device for the production of an artifact in a geopolymeric composite material, in accordance, respectively, with the content of claims 7 and 11 and with a geopolymeric composite material in accordance with claim 15.

In fact, this polymerizable mixture has the enormous advantage of being 3D printable, by implementing the claimed process through the 3D printing device according to the invention, allowing the obtaining of an artifact made of geopolymeric composite material in accordance with the invention. Therefore, through the invention, all the advantages relating to 3D printing are achievable, in particular: the speed and versatility of forming (since it allows the creation of products of any shape in a short time, and with practically changeover times and product changeover times. null). Furthermore, according to the invention, there is an almost total absence of waste and molds, unlike the casting molding processes, usually used with the polymerizing mixtures of the known type which are currently used for the production of building products in a material geopolymer composite of known type. Note that curing blends for the production of a known geopolymer composite material are not suitable for 3D printing.

The geopolymer composite material according to the invention is biocompatible, safe from a food point of view and is recyclable. Furthermore, the creation of a product in said material involves the use of non-hazardous raw materials, a very low energy consumption and therefore very low C02 emissions.

The applicants have shown that the presence of cellulose fibers and chitin and / or chitosan in the polymerizing mixture in accordance with the invention and the heating provided for in the claimed production process allows forming by 3D printing. These curing components are assumed to promote the rheology of the curing blend suitable for 3D printing. In this way, this polymerizable mixture is made plastic and its structural stability is promoted. In particular, it is assumed that chitin and chitosan are responsible for the accelerated formation of a crystalline co-lattice in which the geopolymer is present and which gives the polymerizing mixture characteristics such as to make it 3D printable.

Contrary to any artifact in a ceramic material, which can currently be produced by 3D printing, the production of an artifact in the geopolymer composite material in accordance with the invention does not provide for any firing process, since to complete the polymerization of the claimed polymerizable mixture , a temperature lower than 60 ° C is sufficient, and for the total polymerization a time of about 28 days is foreseen, necessary for the completion of the conversion of the metakaolin and mixture of silicates into a crystalline geopolymer structure.

In addition, it should be noted that the geopolymeric composite material according to the invention does not allow the formation or deposit of limestone on the relative surface and is particularly inert under acid or basic conditions. Therefore it is particularly suitable for the production of containers for the production and / or storage of the aforementioned acidic foods and / or drinks and can be used in particular to contain the production of wine, beer, vinegar and oil. In fact, in accordance with the invention, it is possible to make an artifact in said geopolymer composite material by following good production practices relating to food containers.

Specific forms of implementation and realization of the invention will be described later in this discussion, in accordance with what is reported in the claims and with the aid of the attached drawing tables, in which:

Figure 1 is a schematic perspective view of a 3D printing device according to the invention; And

Figure 2 is a schematic front view of some components of the 3D printing device of Figure 1.

The polymerizable mixture according to the invention can be used for the production of a geopolymer composite material in accordance with the invention. Said polymerizable mixture comprises (and, preferably, consists of) the following powder components: metakaolin, having relative particles smaller than 11 µm; potassium silicate; sodium silicate; lithium silicate, chitin and / or chitosan; cellulose fibers; fillers and / or inert additives, usable for the production of ceramics, and water.

To reduce the 3D printing times of the polymerizable mixture according to the invention, it is gradually preferable, in the following order, that at least 30%, 40% or 50% of the metakaolin particles have dimensions below 2 pm.

This polymerizable mixture can be advantageously used in a production process of an artifact in the geopolymer composite material according to the invention, which obviously involves the production of said geopolymeric composite material. The latter, which clearly includes the related geopolymer, can be obtained by polymerization of said polymerizable mixture and includes chitin, and / or chitosan, and cellulose fibers. This characterizes it with respect to the geopolymeric composite materials of the known art.

The production process in accordance with the invention comprising the following stages:

- prepare a polymerizable mixture in accordance with the invention;

- forming a first manufactured article by continuously dosing said prepared polymerizable mixture and continuously heating the polymerizable mixture while it is being dosed and / or as soon as dosed, so that the local temperature of the polymerizable mixture, as soon as it is heated, is lower than or equal to 80 ° C (preferably 60 ° C);

- once the first manufactured article has been formed, complete the polymerization of the relative polymerizable mixture at a temperature between 35 ° C - 65 ° C to obtain a second manufactured article in said geopolymeric composite material having the same conformation as said first manufactured article. Advantageously, this step is carried out at a temperature between 40 ° C and 60 ° C which allows to speed up the polymerization while obtaining a structurally uniform geopolymeric composite material.

An article made of a geopolymeric composite material in accordance with the invention, obtainable through a production process according to the invention, is therefore preferred, in particular when it is a container for the storage of food, more specifically when it is a jar. , or it is shaped like a barrel or like a barrique.

It is evident that the expenditure of energy for the production of said product is particularly low, since it does not require any cooking process and can be carried out with simple and economical equipment. In fact, this process can be implemented with a 3D printing device 10, in accordance with the invention which includes:

- at least one tank 11, 12;

- a print head 1 comprising a housing 13 which can be fed from said tank 11, 12 and a print nozzle 2 which can be fed from said housing 13, said print head 1 being operable to print a material in 3D; and - heating means 3 arranged near the printing nozzle 2 and operable to heat a 3D printable material at a temperature lower than or equal to 80 ° C while it is being dosed and / or as soon as dosed by said printing nozzle.

As can be seen in Figure 1, the 3D printing device 10 can comprise a base 40 on which to form the first product, a printing head 1 supported by a frame 41 and movable in three directions by means of suitable handling means 42. Note that, according to the invention, the forming of a cylindrical container, having for example a base and a height of 20 cm, has a duration of execution of about 30 - 40 '.

Preferably, said print head is arranged for printing by extrusion. The curing mixture begins to polymerize when the metakaolin comes into contact with sodium and / or lithium and / or potassium silicates in the presence of water, but this is not an immediate reaction. Each curing mixture has a certain setting time, beyond which the curing reaction has progressed to the point that it is not possible to convey this curing mixture. In order to carry out the aforementioned process, it is therefore possible to load in said tank 11, 12 a quantity of polymerizing mixture such as to produce a certain article in a printing phase lasting less than the relative setting time. Typically, the polymerizable mixtures according to the invention have a setting time of about 30-40 ', therefore, by implementing the method in accordance with the independent claim, it is possible to print products that require a printing time lower than this setting time by setting suitably the diameter of the nozzle and the flow of polymerizable mixture that reaches the nozzle itself.

Advantageously, the heating means 3 are integral with the print head 1, in particular with the nozzle, and are preferably arranged to heat at least the terminal part 18 of the printing nozzle 1. As can be seen in Figure 2, an arm 8 can be provided which rigidly connects the heating means 3 to the print head 1. Preferably the terminal part of the printing nozzle painted black on the outside to facilitate the absorption of the heat emitted by the heating means 3.

According to an embodiment of the production process in accordance with the invention and claim, the formation step of the first article is carried out by continuously dosing said polymerizable mixture prepared article is carried out by continuously dosing said polymerizable mixture prepared and heating by irradiating with low power infrared, preferably at low frequency, ie in a range of wavelengths comprised within 0.72 -1.5 µm. Correspondingly, it is preferable that, in the 3D printing device 10 according to the invention, said heating means 3 comprise an infrared irradiation device 3 which can be operated to irradiate a printed material from the printing nozzle 2 while it is being dosed and / or as soon as dosed. In this way it is possible to heat both the printing nozzle (ie the polymerizing mixture while it is being dosed) and the polymerizing mixture as soon as it is dosed. This infrared irradiation device 3 can comprise at least one infrared diode. Considering the typical dimensions of the printing nozzles, it is gradually preferable, in the following order, that the heating means, in particular the infrared irradiation device 3, supply energy in the following ranges at 2.76 x 10 <'19> J - 1.33 x 10 <'19> J; 2.21 x 10 <19> J - 1.52 x 10 <19> J; and 1.99 x 10 <19> J and 1.80 x 10 <'19> J.

It is particularly preferable that in said polymerizing mixture at least 50% of the cellulose fibers have a relative length equal to or less than 100 μΐτι and / or said chitosan has a degree of deacetylation equal to or greater than 80%, more preferably 85%.

Preferably said chitin and / or chitosan are present in said polymerizable mixture in a relative percentage, calculated by weight / weight with respect to the total of the polymerizable mixture of 1 - 5%, more preferably 1 - 3%. It is assumed that they are responsible for the accelerated formation of a crystalline coreticle in which the geopolymer is present, thus accelerating the formation of the first artifact, ie the printing times. Furthermore, it is preferable that this polymerizable mixture includes a percentage of cellulose fibers, calculated in weight / weight with respect to the total of the polymerizable mixture, of 1 - 3%, more preferably of 1 - 1.15%.

Correspondingly, a geopolymeric composite material according to the invention is preferred which comprises chitin and / or chitosan in a relative percentage of 1 - 5%, preferably 1 - 3%, and cellulose fibers in a relative percentage of 1 - 3%, preferably 1 - 1.5%, where the percentages are calculated by weight / weight with respect to the total of the geopolymeric composite material, because this simplifies the production of the related product in said material.

Considering the general formula of an alkali metal silicate given by: x Si02 * M20, where M is the relative alkali metal and x is the molar ratio between the moles Si02 and the moles M20, in accordance with a preferred aspect of the present invention called potassium silicate, sodium silicate and lithium silicate preferably have a relative molar ratio lower than 2, 3 and 4 respectively. According to a particularly preferred embodiment, said components are present in the percentages reported in table 1 and calculated by weight / weight with respect to the total of the polymerizable mixture.

- powdered metakaolin: 15 - 45%, more preferably 15 - 25%; - sum of the percentages of: 10 - 32%, more preferably 10 - 18%; potassium silicate, silicate of

sodium and lithium silicate:

- chitin and / or chitosan: 1 - 5%, more preferably 1 - 3%; - cellulose fibers: 1 - 3%, more preferably 1 - 1.5%; - fillers and / or inert additives: 34 - 79%, more preferably 34 - 50.5%; and - water to taste at 100%. q.s. at 100%.

Table 1

In each embodiment of the polymerizable mixture, said metakaolin in powder preferably has a particle size distribution in which at least 50% of the particles have dimensions below 2 µm and, preferably, exhibit pozzolanic activity (measured with the Chapelle test) not lower than 1200 mg of Ca (OH) 2 per gram of metakaolin. This greatly increases the specific surface of the metakaolin, making it particularly reactive, and decreases the times of obtaining the geopolymeric material according to the invention, and consequently also of the manufactured article in said material.

It is preferable that the polymerizable mixture comprises said silicates in the following percentages, calculated by weight / weight with respect to the total of the polymerizable mixture:

- potassium silicate: 7.5 - 22.5%, more preferably 7.5 - 12.5%; - sodium silicate: 2 - 6%, more preferably 5 - 4%; And

- lithium silicate: 1 - 1.5%, more preferably 0.5 - 1%.

This allows to shorten the polymerization times of the polymerizable mixture. The presence of the three silicates, potassium, sodium and lithium, in particular in the quantities indicated above, gives the final product particular qualities of mechanical resistance not otherwise obtainable by the use of a single silicate. In each embodiment of the polymerizable mixture said fillers and / or inert additives may comprise a relative percentage, of 0.2 - 2% (gradually more preferably, in the following order at 0.2 - 0.4% 1,3 - 1.8% and 1.5%), calculated by weight / weight with respect to the total of the polymerizable mixture.

This allows to reduce the reduction of the final porosity of the geopolymeric material allowing to create a food container in said material, whose internal containment wall can not be subjected to further processing, such as for example an enamelling process similar to that relating to dishes. in porcelain. Therefore, the production process of said container is further simplified, further reducing the relative times, costs, labor and simplifying the equipment relating to its production.

To make the polymerizable mixture according to the invention, the mica can be used as it is. Alternatively, you can use the Ball Clay, also known as also called “Terra Arancio Dolce” or “Terra Sigillata”. This is because Ball Clay is a sedimentary kaolin clay which is essentially made up of 20 - 80% kaolinite, 10 - 25% mica and 5 - 65% quartz. Therefore, the polymerizable mixture according to the invention can comprise Ball Clay in a relative percentage, calculated by weight / weight with respect to the total of the polymerizable mixture, of 1 - 5%, more preferably 1 - 2%, advantageously 1.25 - 1.5%.

A geopolymeric composite material according to the invention is preferred which further comprises mica, in particular in a relative percentage, by weight / weight of 0.2 - 2%, more preferably of 0.2 - 0.4%, advantageously of 1, 3 - 1.8%. The presence of mica in the geopolymeric composite material according to the invention can be easily verified through specific analyzes.

It is preferable that in the polymerizable mixture in accordance with the invention, said fillers and / or inert additives include at least one of the following additional components, in the following respective percentages, calculated by weight / weight with respect to the total of the polymerizable mixture:

- mullite 20 - 40%, more preferably 20 - 30%;

- quartz 10 - 25%, more preferably 10 - 15%;

- sodium feldspar 1 - 3%, more preferably 1 - 2%;

- potassium feldspar 1 - 3%, more preferably 1 - 2%; And

- 1 - 3% zirconium silicate, more preferably 1 - 1.5%.

In particular, the presence of mullite confers a high thermal stability to flame and a very high mechanical resistance of the geopolymeric composite material obtainable with the mixtures in accordance with the invention that comprise it. In particular, mullite allows the geopolymer composite material according to the invention not to overheat. For this reason, the latter is particularly suitable for food containers that involve fermentation involving the production of heat.

The zirconium silicate increases the hardness of the geopolymeric composite material obtainable with the mixtures in accordance with the invention that include it.

On the other hand, quartz, sodium feldspar and potassium feldspar are particularly preferred fillers as they allow the creation of a geopolymeric composite material having a composition similar to the composition of a classic ceramic thanks to their property of giving a glassy appearance. and polished to the second artifact. According to a particularly preferred embodiment, the polymerizable mixture comprises each of the further components in the relative aforementioned concentrations.

In particular, the polymerizable refluxing mixtures of the formulations reported in the following table 2 are particularly preferred, where the percentages of the relative components are calculated in weight / weight with respect to the total of the formulation.

Formulation A Formulation B Formulation C components:%%% Metakaolin 15-45 15-25 20-25 Potassium Silicate 7.5-22.5 7.5-12.5 7.5-10 Sodium Silicate 2-6 2 -4 2,4 -3,2 Lithium silicate 0,5 -1,5 0,5-1 0,75-0,9 Mullite 20-40 20-30 25-28 Quartz 10-25 10-15 12, 5-14 Sodium feldspar 1 -3 1 -2 1.25-1.5 Potassium feldspar 1 -3 1 -2 1.25-1.5 Zirconium silicate 1 -3 1 - 1.5 1.25- 1,4 Chitin and / or Chitosan 1 -5 1 -3 1.25-2 Mica 0.2-1 0.2 -0.4 1.3-1.8 Cellulose fibers 1 -3 1 - 1.5 1.25-1.5 Water q.s. to 100 q.b. to 100 q.b. a 100 Table 2

Formulation B is more preferable than formulation A because it gives rise to a geopolymeric composite material particularly suitable to be used to contain the aforementioned foods and / or beverages. Furthermore, formulation C is preferable to the other two because it allows you to further optimize 3D printing times.

In these formulations, instead of mica as it is, Ball Clay can be used in the percentages indicated in table 3.

Formulation A Formulation B Formulation C Ball Clay 1 - 5% 1 - 2% 1.25-1.5% Table 3

Correspondingly, the compositions of the geopolymeric composite material reported in the following table 4 are preferred, where the percentages of the relative components are calculated in weight / weight with respect to the total of the formulation.

Formulation D Formulation E Formulation F components:%%% Geopolymer 30-90 30-50 25-30 Mullite 20-40 20-30 25-28 Quartz (44 micron) 10-25 10-15 12.5-14 Sodium feldspar 1 -3 1 -2 1.25-1.5 Potassium feldspar 1 -3 1 -2 1.25-1.5 Zirconium silicate 1 -3 1 - 1.5 1.25-1.4 Formulation D Formulation E Formulation F Chitin and / or Chitosan 1 -5 1 -3 1.25-2 Mica 0.2-1 0.2 -0.4 1.3- 1.8 Cellulose fibers 1 - 3 1 - 1.5 1.25 - 1.5

Water q.s. to 100 q.b. to 100 q.b. to 100

Table 4

Formulation E is more preferable than formulation D and formulation F is preferable to the other two.

According to a preferred embodiment of the production process in accordance with the invention, the stage of preparation of said polymerizable mixture comprises the following sub-stages:

- mix said: potassium silicate, sodium silicate; lithium silicate; chitin and / or chitosan; cellulose fibers; fillers and / or inert additives, in relative quantities predisposed to obtain a first predetermined quantity of polymerizable mixture, with a first quantity of water sufficient to obtain a first pumpable mud suspension (ie a first "slurry");

- mixing said metakaolin in powder, in a relative quantity predisposed to obtain said first predetermined quantity of polymerizable mixture, with a second quantity of water, with the sum of the first and second quantities of water equal to the quantity of water foreseen in the first predetermined quantity of polymerizable mixture, obtaining a second pumpable mud suspension (ie a second "slurry");

- continuously mixing, in a print head 1 of a 3D printing device 10, said first and second pumpable mud suspension, in relative quantities proportional to the relative quantities necessary to obtain said first predetermined quantity of polymerizable mixture, producing continuously, a second predetermined quantity of polymerizable mixture smaller than said first predetermined quantity of polymerizable mixture;

in which the step of forming the first product comprises 3D printing, continuously and through a printing nozzle 2 provided in said printing head 1, of the second predetermined quantity of polymerizable mixture produced and the continuous heating of the second predetermined quantity of polymerizable mixture while it is being dosed or as soon as it is dosed.

Preferably, heating is carried out by infrared (IR) radiation. This process can therefore be carried out with a second 3D printing device 10 - a first and a second tank 11, 12;

- metering means arranged for, when the first and second tanks 11, 12 contain, respectively, a first and a second pumpable sludge suspension, to continuously dose, in said housing 13, relative predetermined quantities of said suspensions; And

- means for mixing and feeding the material to be printed arranged in said housing 13, with said mixing and feeding means operable to mix said predetermined metered quantities of said first and second mud slurry, to obtain a 3D printable mixture and to continuously feed said printing nozzle 2 with said obtained printable mixture.

With reference to Figure 2, said mixing and feeding means can comprise an electric motor 7 and a screw 6, or auger, which, driven by the shaft of the motor 7, pushes the material to be printed present in the housing 13 towards the nozzle. print 2. In this case the print head 1 is therefore structured as an extruder.

When two tanks 11, 12 are provided, once said first and second tanks 11, 12 have been loaded with said first and second muddy suspension respectively, it is possible to create any type of product, even of large dimensions, without having to worry about the setting time. of the polymerizing mixture, because it is printed as soon as it has been obtained, since the preparation of said second predetermined quantity of polymerizable mixture takes place in the housing 13 of the printing head 1 immediately before the relative 3D printing.

According to a particularly inventive embodiment of the 3D printing device 10 according to the invention, said metering means comprise a control and command unit, also called PLC, and a first and a second metering nozzle 31, 32, arranged, respectively downstream of the first and second tanks 11, 12, which can be operated by the control and command unit to convey, in said housing 13, said predetermined quantities of said first and second pumpable muddy suspension.

As visible in Figure 2, the two dosing nozzles 31, 32 dose the respective muddy suspensions in the housing 13 through an opening 14 for accessing the housing 13.

The control and command unit then provides for the correct dosage of the two pumpable mud suspensions in the required mixing ratio.

In order to increase the stability in acidic and basic conditions of said second product made of a geopolymeric composite material according to the invention, the production process can advantageously further comprise the following phase:

- applying (preferably by spraying) on at least a portion of the surface of said second manufactured article an aqueous solution or suspension containing a compound selected from the group consisting of: zinc citrate; zinc tartrate; colloidal silica; and their mixtures;

- rinsing said surface portion of the second article with water.

Preferably, the zinc citrate, the zinc tartrate and colloidal silica are present in these solutions or suspensions at a relative concentration equal to about Γ1% by weight / weight.

The zinc and / or silica present in said solutions / suspensions is incorporated into the crystal lattice that originates from the reaction of the silicates with the metakaolin, accelerating the formation of the geopolymer and preventing the deposition of calcium and / or magnesium carbonates.

This allows to obtain a container according to the invention comprising a containment wall having a relative surface, in which the percentage by weight / weight of the zinc contained in the containment wall is greater at the relative surface than inside the wall. This container is therefore particularly suitable to be used for the production and storage of food and / or drinks such as beer, wine, oil and vinegar, in particular when it is shaped like a jar, a barrel or a barrique.

It is understood that the above has been described by way of non-limiting example, and any variants of a practical-applicative nature are understood to fall within the protective scope of the invention claimed below.

Claims (19)

CLAIMS 1. Polymerizable blend usable for the production of a geopolymer composite material, said polymerizable blend comprising the following powder components: metakaolin, having relative particles smaller than 11 µm; potassium silicate; sodium silicate; lithium silicate, chitin and / or chitosan; cellulose fibers; fillers and / or inert additives, usable for the production of ceramics, and water. 2. Polymerizable blend according to claim 1, wherein at least 50% of the cellulose fibers have a relative length equal to or less than 100 μηη and / or said chitosan has a degree of deacetylation equal to or greater than 80%. 3. Polymerizable mixture according to claim 1 or 2, in which said components are present in the following percentages, calculated by weight / weight with respect to the total of the polymerizable mixture: - metakaolin 15 - 45%; - sum of the percentages of: potassium silicate, sodium silicate and lithium silicate: 10 - 32%; - chitin and / or chitosan: 1 - 5%; - cellulose fibers: 1 - 3%; - fillers and / or inert additives: 34 - 79%; - water to taste at 100% 4. Polymerizable mixture according to any preceding claim, comprising said silicates in the following percentages, calculated by weight / weight with respect to the total of the polymerizable mixture: - potassium silicate: 7.5 - 22.5%; - sodium silicate: 2 - 6%; And - lithium silicate: 0.5 - 1.5%. 5. Polymerizable mixture according to any preceding claim, wherein said fillers and / or inert additives comprise mica in a relative percentage of 0.2% - 2%, calculated by weight / weight with respect to the total of the polymerizable mixture. 6. Polymerizable mixture according to any preceding claim, wherein said fillers and / or inert additives comprise at least one of the following components, in the following respective percentages, calculated by weight / weight with respect to the total of the polymerizable mixture: - mullite 20 - 40%; - quartz 10 - 25%; - sodium feldspar 1 - 3%; - potassium feldspar 1 - 3%; And - 1 - 3% zirconium silicate. 7. Production process of an artifact in a geopolymer composite material, comprising the following phases: - preparing a polymerizable mixture according to any preceding claim; - forming a first manufactured article by continuously dosing said prepared polymerizable mixture and continuously heating the polymerizable mixture while it is being dosed and / or as soon as dosed, so that the local temperature of the polymerizable mixture, as soon as it is heated, is lower than or equal to 80 ° C; - once the first manufactured article has been formed, complete the polymerization of the relative polymerizable mixture at a temperature between 35 ° C - 65 ° C to obtain a second manufactured article in said geopolymeric composite material having the same conformation as said first manufactured article. 8. Production process according to the preceding claim in which the formation step of the first article is carried out by continuously dosing said prepared polymerizable mixture and heating by irradiating with infrared rays. 9. Production process according to claim 7 or 8, wherein the step of preparing said polymerizable mixture comprising the following sub-steps: - mixing said: potassium silicate, sodium silicate; lithium silicate; chitin and / or chitosan; cellulose fibers; fillers and / or inert additives, in relative quantities predisposed to obtain a first predetermined quantity of polymerizable mixture, with a first quantity of water sufficient to obtain a first pumpable mud suspension; - mixing said metakaolin in powder, in a relative quantity predisposed to obtain said first predetermined quantity of polymerizable mixture, with a second quantity of water, with the sum of the first and second quantities of water equal to the quantity of water foreseen in the first predetermined quantity of polymerizable mixture, obtaining a second pumpable mud suspension; - continuously mixing, in a printing head (1) of a 3D printing device, said first and second pumpable sludge suspension, in relative quantities proportional to the relative quantities prepared to obtain said first predetermined quantity of polymerizable mixture, producing continuously, a second predetermined quantity of polymerizable mixture smaller than said first predetermined quantity of polymerizable mixture; in which the step of forming the first product comprises the 3D printing, continuously and through a printing nozzle (2) provided in said printing head (1), of the second predetermined quantity of polymerizable mixture produced and the continuous heating of the second predetermined quantity of polymerizable mixture while it is being dosed or as soon as it is dosed. 10. Production process according to any one of claims 7 to 9, further comprising the following step: - applying on at least a portion of the surface of said second manufactured article an aqueous solution or suspension containing a compound selected from the group consisting of: zinc citrate; zinc tartrate; colloidal silica; and their mixtures; - rinsing said surface portion of the second article with water. 11. 3D printing device, comprising: - at least one tank (11, 12); - a print head (1) comprising a housing (13) which can be fed from said tank (11, 12) and a printing nozzle (2) which can be fed from said housing (13), said print head (1) being operable to print a 3D material; And - heating means (3) arranged near the printing nozzle (2) and operable to heat a 3D printable material at a temperature lower than or equal to 80 ° C while it is being dosed and / or as soon as dosed by said printing nozzle . 3D printing device according to claim 11, wherein said heating means (3) comprise an infrared irradiation device (3) operable to irradiate a printed material from the printing nozzle (2) while it is being dosed and / or as soon as dosed. 13. 3D printing device according to claim 11 or 12, comprising: - a first and a second tank (11, 12); - metering means arranged for, when the first and second tanks (11, 12) contain, respectively, a first and a second pumpable sludge suspension, to continuously dose in said housing (13) relative predetermined quantities of said suspensions; And - means for mixing and feeding the material to be printed arranged in said housing (13), with said mixing and feeding means operable to mix said predetermined metered quantities of said first and second muddy suspension, to obtain a 3D printable mixture and to feed in continuous said printing nozzle (2) with said obtained printable mixture. 14. 3D printing device according to the preceding claim, in which said metering means comprise a control and command unit and a first and a second metering nozzle (31, 32), arranged respectively downstream of the first and second tank (11, 12), which can be operated by said control and command unit to convey said predetermined quantities of said first and second pumpable mud suspension into said housing (13). 15. Geopolymeric composite material, obtainable by polymerization of a polymerizable mixture according to any one of claims 1 to 6, comprising chitin, and / or chitosan, and cellulose fibers. 16. A geopolymeric composite material according to the preceding claim further comprising mica. 17. Product made of a geopolymeric composite material in accordance with the previous claim obtainable through a production process in accordance with claims 7 - 10. 18. Product according to the preceding claim, said product being a container for storing food. 19. Container according to the preceding claim, comprising a containment wall having a relative surface, in which the percentage by weight / weight of the zinc contained in the containment wall is greater at the relative surface than inside the wall.