Process for obtaining concentrated silica zeolite activator, concentrated silica zeolite activator and use thereof

Abstract

The present invention relates to a process for obtaining a silica zeolite activator from the combination of a source of silica (SiO2), a source of alumina (Al2O3) and a source of sodium (Na2O). This process involves a unique electrified alkaline fusion heat treatment and involves low temperatures and energy consumption, contributing to a reduction in the CO2 footprint. In addition, the present invention relates to the concentrated solid silica zeolite activator thus obtained, which has reactive silica and zeolite phases. The present invention also relates to the use of silica zeolite for alkaline activation of alkali-activated cement.

Description

PROCESS FOR OBTAINING CONCENTRATED SILICO-ZEOLITIC ACTIVATOR, CONCENTRATED SILICO-ZEOLITIC ACTIVATOR, AND USE. FIELD OF THE INVENTION

[0001] The present invention relates to a process for obtaining an alkaline zeolitic siliceous activator from the combination of a silica source (SiO2), an alumina source (Al2O3), and a sodium source (Na2O). The process proposed herein involves the electrified alkaline fusion of the raw material. Furthermore, the present invention relates to the concentrated zeolitic siliceous activator obtained and the use of the zeolitic siliceous activator for the alkaline activation of alkali-activated cement. BACKGROUND OF THE INVENTION

[0002] Cement is the second most consumed material in the world, accounting for approximately 8% of global CO2 emissions. Conventional cement generally requires high temperatures to be produced and, consequently, has a high energy demand and associated CO2 footprint. Total global CO2 emissions from this industry exceed 2.5 Gt, of which approximately 60% come from the high-temperature decomposition of the materials used and 40% from the combustion of fuels. In this context, Portland cement has a proven track record; however, its production process requires the materials to be subjected to high clinkerization temperatures (1400°C-1500°C), directly influencing energy demand and the associated CO2 footprint.

[0003] In this scenario, alkali-activated cements stand out as an alternative with a lower environmental impact, since they do not involve high-temperature heat treatments in their production. Furthermore, alkali-activated cements perform well in terms of mechanical properties and durability. Alkali-activated cements use aluminosilicates as precursors, which may consist of industrial waste and / or byproducts. Furthermore, alkali-activated cements use high-alkaline activators to increase the pH of the solution and accelerate reactions (in the presence of water). Alkaline activators are generally commercial products and, depending on the proportion and type, are responsible for the highest CO2 emissions within the composition of alkali-activated cements. It is worth mentioning that alkali-activated cements also allow the incorporation of waste and residues in the production of activators.

[0004] Alkaline activators traditionally consist of one or more of hydroxides, silicates, and carbonates. Hydroxides are commonly NaOH, KOH, Ca(OH)2, among others. They provide a slower and less effective reaction at room temperature, and therefore may require thermal curing and result in lower initial strengths. Silicates are commonly Na2SiO3, K2SiO3, among others. They provide faster reactions, higher initial strength, and a more homogeneous matrix. Carbonates, in turn, are commonly Na2CO3, among others. Mixing the various types of activators is also common, so that each contributes specific properties.

[0005] When in contact with water, alkali-activated cements develop reaction nuclei, which can form NASH or CASH gels. The proportion of each depends on the composition of the materials involved in the reaction, particularly the presence or absence of CaO in the precursors. Over time, the gel matrix expands until a resistant solid is formed.

[0006] In view of the above, alkali-activated cements are effective and more sustainable alternatives to conventional cement. However, their widespread use is still limited by the lack of standardization of various precursor materials, a lack of activator materials and precursors in certain regions, and other factors. Furthermore, measures can still be taken to reduce the CO2 footprint of alkali-activated cement, even though it is already very low, such as the development of activators based on tailings and / or residues and through low-temperature, low-energy processes. Currently, the industry still lacks activators with low CO2 emissions. Mineral components that can chemically and physically aid in the alkali-activated matrix and that, in addition, have a physical form that allows their transport to locations lacking accessible activators in terms of volume and price. Thus, the process for obtaining a silico-zeolitic alkaline activator as proposed by the present invention is aligned with this context and can boost the use of alkali-activated cements, contributing to the global reduction of CO2 emissions.

[0007] The present invention proposes a process route for obtaining a concentrated silico-zeolitic activator from the combination of a silica source (SiO2), an alumina source (Al2O3), and a sodium source (Na2O), each in a specific proportion. These SiO2 and Al2O3 sources can come from pure raw materials or from waste from various industries. The proposed process route involves the electrified alkaline fusion of the powdered raw material, preferably agglomerated (preferably pelletized), at a temperature between approximately 400°C and approximately 600°C. This results in a concentrated alkaline activator with reactive siliceous and zeolitic phases, which contribute beneficially to the performance of alkali-activated cement matrices.

[0008] The silico-zeolitic activator of the present invention is solid, in powder form, preferably agglomerated (more preferably pelletized), so as to constitute a one-part alkali-activated cement system (alkali-activated cements are considered one-part when both precursor and activator are solid).

[0009] The state of the art concerning the present invention reveals efforts related to obtaining alternative activators for alkali-activated cements / geopolymers, including activators obtained from mining waste and slag from steel-metallurgical processes.

[0010] The scientific article entitled “Producing sodium silicate powder from iron ore tailings for use as an activator in one-part geopolymer binders” refers to the use of iron ore tailings (IOT) as a source of silica (SiO2) to produce An alternative form of sodium silicate (SS) for use as an activator in a one-part geopolymer. In this context, this document teaches the mixing of iron ore tailings with water and sodium hydroxide (97% purity micropearls) and heating the mixture at 350°C for 2 hours in an electric furnace. Unlike the present invention, this document specifically refers to the production of sodium silicate, in which the process involves mixing water and sodium hydroxide with the starting material.

[0011] Patent document PI0101413-7A refers to the production of sodium silicate from leaching between slags resulting from iron and steel metallurgical processes and an alkaline substance, which may be sodium hydroxide. According to this document, no heat treatment is necessary since the raw material (slag) already contains the heat of reaction (1500°C). Furthermore, this document refers to the production of sodium silico-aluminate, either by utilizing the aluminum oxide (Al2O3) content present in the slag or by adding any aluminum mineral. Unlike the present invention, PI0101413-7A refers to a hydrothermal process for the production of sodium silicate from iron and steel metallurgical slags, using sodium hydroxide.Despite mentioning the possibility of incorporating aluminum mineral as raw material in the proposed process, the objective of PI0101413-7A with the use of aluminum mineral is to obtain sodium silicoaluminate, and this document is silent regarding a process involving alkaline fusion heat treatment in order to generate a product with reactive siliceous and zeolitic phases.

[0012] The scientific article entitled "Transformation of iron ore and serpentinite mining tailings into silicates and other value-added products" refers to the production of value-added materials from iron ore and serpentinite mining tailings. In one of the disclosed pathways, this article reveals the production of sodium silicate from reactions of sodium hydroxide with serpentinite and iron ore mining tailings. In this context, the use of sodium silicate thus produced as an alkaline activator for the production of geopolymers. According to this document, a hydrothermal route was conducted, in which iron waste is mixed with solid NaOH and water, in a closed system under pressure and temperature of 200°C. Unlike the present invention, this document refers specifically to the production of sodium silicate, in which the process involves mixing water and sodium hydroxide with the starting material followed by a hydrothermal route.

[0013] Patent document BR102019018080-3B1 refers to a process for producing sodium silicate from sandy mineral processing tailings as a source of silica. In this context, this patent mentions the use of the sodium silicate thus produced in the manufacture of geopolymers and materials activated in an alkaline medium. According to the process proposed by the patent in question, a mixture of sodium hydroxide solution with a concentration between 33 and 38 mol / L and the sandy tailings is heat treated at a temperature between 400°C and 500°C for approximately 2.5 hours, producing sodium silicate powder. Unlike the present invention, patent BR102019018080-3B1 specifically addresses the production of sodium silicate powder from sandy mineral processing tailings.

[0014] As explained above, there are prior art efforts dedicated to obtaining alternative alkaline activators for alkali-activated cements / geopolymers, including activators obtained from mining tailings and slag from steel and metallurgical processes. Furthermore, the prior art also envisions solutions concerning the production of powdered activators. However, the prior art is silent on activators with mineral components that can chemically and physically assist in the alkali-activated matrix in the molds of the silico-zeolitic alkaline activator as proposed by the present invention. Furthermore, the prior art does not mention the pelletized format proposed by the present invention, which allows the activator to be transported more safely, without loss of material and control of reactivity. As further detailed below, the present invention aims to solve the deficiencies of the prior art described above. SUMMARY OF THE INVENTION

[0015] The present invention relates to a process for producing a concentrated siliceous-zeolitic activator suitable for use in alkali-activated cements. Briefly, the proposed process comprises a single alkali fusion heat treatment (more specifically, electrified alkali fusion), which generates reactive siliceous and zeolitic phases.

[0016] The raw material of the proposed process consists of the combination of materials that result, after heat treatment (which results in the loss of free and chemically bound water), in a chemical composition of approximately 25% to approximately 40% sodium (Na2O), approximately 5% to approximately 15% alumina (Al2O3) and approximately 45% to approximately 70% silica (SiO2).

[0017] Optionally, after dosing and homogenizing the raw material and before heat treatment, the process of the present invention includes a pre-processing mixture agglomeration step. Agglomeration can be carried out in pelletizing discs, pelletizing drums, or any other equipment that allows for rotation control (and, therefore, agglomeration), using water as a binder (in an amount between approximately 13% and approximately 15% of the total mass of solids). The agglomerates are then dried at temperatures between approximately 40°C and approximately 100°C to remove moisture. If pelletizing is not possible or if the application is desirable, the material can be processed in powder form.

[0018] The heat treatment stage, in turn, is conducted in a static or rotary electric furnace, without the possibility of combustion or contact with fossil gases, at temperatures between approximately 400°C and approximately 600°C, and a residence time of approximately 45 minutes to approximately 1 hour (in a rotary furnace) or approximately 3 hours (in a static furnace). The resulting activator is then cooled and processed.

[0019] The activator obtained by means of the process of the present invention, in powder or pellet form, is composed of about 25% to about 50% silicate species, about 1% to about 30% zeolite species and about 20% to about 50% amorphous silica or in quartz form.

[0020] When using the alkaline activator obtained in the production of alkali-activated cement, it must be ground to a particle size of less than approximately 75 μm and combined with a reactive precursor to form the alkali-activated cement. The amount of activator to be used will depend on the type of precursor used for the cement, and can be used at a level ranging from approximately 15% to approximately 35% of the total mass of alkali-activated cement.

[0021] In view of the above, the present invention aims to provide an alkaline activator for alkali-activated cement through a process involving low temperatures and energy consumption, contributing to the reduction of the CO2 footprint of the alkali-activated cement. Thus, the present invention contributes to the reduction of CO2 emissions associated with the construction market.

[0022] Furthermore, the present invention enables the production of an agglomerated activator that can be mixed with the powdered or granulated precursor to produce alkali-activated cement, requiring only the addition of water to initiate the reaction. This provides benefits related to handling, transportation, safety during use, and production scalability. Furthermore, when producing the silico-zeolitic activator in pelletized form, this format allows for safer transport, without material loss, and allows for reactivity control.

[0023] The above-mentioned objects and other advantages of the present invention will become more evident from the following description. BRIEF DESCRIPTION OF THE FIGURES

[0024] Figure 1 illustrates a ternary diagram situating the silico-activator zeolitic of the present invention among the main activators of alkali-activated cement.

[0025] Figure 2 illustrates a photograph of the silico-zeolitic activator of the present invention, in pellet form.

[0026] Figure 3 illustrates a diagram with the production flow of the silico-zeolitic activator of the present invention and procedures necessary for its use in alkali-activated cement.

[0027] Figure 4 illustrates the identification of the mineral phases, by means of X-ray diffraction, of three samples of activators obtained by means of the process of the present invention.

[0028] Figure 5 illustrates compressive strength results of an alkali-activated cement comprising 15% silico-zeolitic activator according to the present invention and 85% blast furnace slag as precursor.

[0029] Figure 6 illustrates compressive strength results of an alkali-activated cement comprising 20% ​​silico-zeolitic activator according to the present invention and 80% blast furnace slag as precursor.

[0030] Figure 7 illustrates compressive strength results of an alkali-activated cement comprising 25% silico-zeolitic activator according to the present invention and 75% blast furnace slag as precursor.

[0031] Figures 8a and 8b illustrate calorimetry results of an alkali-activated cement comprising 15% silico-zeolitic activator according to the present invention and 85% blast furnace slag as precursor.

[0032] Figures 9a and 9b illustrate calorimetry results of an alkali-activated cement comprising 20% ​​silico-zeolitic activator according to the present invention and 80% blast furnace slag as precursor.

[0033] Figures 10a and 10b illustrate calorimetry results of an alkali-activated cement comprising 25% zeolitic-silica activator according to the present invention and 75% blast furnace slag as precursor. DETAILED DESCRIPTION OF THE INVENTION

[0034] In order to achieve the objectives described above, the present invention provides a process for obtaining a silico-zeolitic alkaline activator for use in alkali-activated cements.

[0035] According to the present invention, the raw material for the process in question consists of a combination of a major source of silica (SiO2), an alumina source (Al2O3), and a sodium source (Na2O). The major source of SiO2 must be predominantly quartzose, consisting of sand from any source or quartzose ore, with a SiO2 content >90%. The sodium source (Na2O) consists of granular or flaky NaOH. The alumina source (Al2O3) consists of kaolinites, kaolinitic waste from intrusive rocks, decomposed mafic rocks, friable shales, among others, with the possibility of also contributing as a silica source to the system.

[0036] Initially, the raw material components are taken to a dosing and homogenization stage to obtain the pre-processing mixture. The raw material for the proposed process consists of a combination of materials that result, after heat treatment (which results in the loss of free and chemically bound water), in a chemical composition of approximately 25% to approximately 40% sodium (Na2O), approximately 5% to approximately 15% alumina (Al2O3), and approximately 45% to approximately 70% silica (SiO2).

[0037] Optionally, the pre-processing mixture is sent to an agglomeration stage. This agglomeration stage preferably consists of a pelletizing stage. This stage is performed in pelletizing discs, pelletizing drums, or any other equipment that allows for rotation control (and, therefore, agglomeration), using water as a binder (in an amount between approximately 13% and approximately 15% of the total mass of solids). The agglomerates are then dried at temperatures between approximately 40°C and approximately 100°C to remove moisture.

[0038] Then, the material (agglomerated or powdered) is taken to the stage Heat treatment, which consists of electrified alkaline fusion and is carried out in a static or rotary furnace, without the possibility of combustion or contact with fossil gases. This heat treatment occurs at temperatures between approximately 400°C and approximately 600°C, with a residence time of approximately 45 minutes to approximately 1 hour (in a rotary furnace) or approximately 3 hours (in a static furnace). The resulting activator is then cooled and processed.

[0039] The alkaline fusion of the combination of oxides of the raw material, in the specific proportions as defined in the present invention, allows the combined formation of reactive siliceous and zeolitic phases from the pre-processing mixture.

[0040] Considering sodium hydroxide as the sodium source, it has a melting temperature of 323°C. Above this temperature, in a molten state, it surrounds SiO2 and Al2O3 particles, enabling alkaline leaching. SiO2, in turn, combined with Na2O, enables the formation of silicate species such as Na4SiO4, Na2SiO3, and Na6Si2O7. Similarly, the combination of SiO2, Al2O3, and Na2O enables the formation of different zeolite species such as Na2Al2Si3O10.2H2O, NaAlSi2O6·H2O, Na2Al2Si4O12.6H2O, and Na8Al6(SiO4)6(OH)2. The formation of the zeolitic structure from a silicate occurs through the replacement of a silicon atom (oxidation number +4) by an aluminum atom (oxidation number +3), resulting in a residual negative charge in the crystal lattice. In addition, other siliceous phases are formed. The amount of siliceous and zeolitic phases is determined by the input composition and processing conditions.

[0041] In the context of using the materials obtained as alkaline activators to obtain alkali-activated cements, the aforementioned reactive siliceous and zeolitic phases contribute beneficially to the formation of the cement.

[0042] The siliceous phases, which are amorphous or semicrystalline, allow the formation of silicon-rich tetrahedral molecular bonds, favoring the formation of denser and more stable structures. Furthermore, these These phases allow for an increase in pH and the initiation of the reaction with the precursors to obtain the alkali-activated cement. Furthermore, semicrystalline quartz nanoparticles can also be observed in the resulting activator, which have the potential to act as nucleation points and accelerate gel formation in the cement.

[0043] Zeolitic phases, in turn, are crystalline and porous structures of silica and alumina tetrahedrons linked by shared oxygen atoms. It is worth mentioning that these zeolitic phases are commonly found as products of the geopolymerization process; however, this invention proposes incorporating them as a raw material. Increasing the amount of zeolite in the alkali-activated cement matrix is ​​beneficial because it contributes to the formation of the NASH gel and, consequently, to the development of strength. The unreacted fraction, when present, enhances other properties such as the ability to immobilize heavy metals (through cation exchange), sodium stabilization, and increased surface area.

[0044] The activator obtained by the process of the present invention is solid (in powder form), preferably in agglomerated form and, more preferably, in pelletized form. Therefore, the activator product of the present invention is suitable for constituting a one-part alkali-activated cement system. Said product is composed of about 25% to about 50% silicate species, about 1% to about 30% zeolite species, and about 20% to about 50% amorphous silica or quartz form.

[0045] Figure 1 illustrates a ternary diagram placing the silico-zeolitic activator of the present invention among the main alkali-activated cement activators.

[0046] Figure 2, in turn, illustrates a photograph of the silico-zeolitic activator obtained according to the present invention, in pellet form.

[0047] The present invention also envisages the use of the activator obtained through the proposed process for alkaline activation in the production of alkali-activated cements. In this context, the cement must be ground to a particle size of less than approximately 75 μm to be combined with a reactive precursor to form the alkali-activated cement. The amount of activator to be used will depend on the type of precursor used for the cement, as follows:

[0048] – approximately 15% w / w to approximately 25% w / w for cements with blast furnace slag as a precursor;

[0049] – about 20% w / w to about 30% w / w for cements with blast furnace slag + calcined clays as precursors; and

[0050] – about 25% w / w to about 35% w / w for cements with calcined clays or fly ash as precursor.

[0051] Figure 3 illustrates a diagram with the production flow of the silico-zeolitic activator of the present invention and procedures necessary for its use in alkali-activated cement, as detailed above.

[0052] The description given thus far of the subject matter of the present invention should be considered only as one or more possible embodiments, and any particular features introduced therein should be understood only as something that was written to facilitate understanding. Therefore, they should not be considered as limiting the invention, which is limited to the scope of the claims.

[0053] The examples presented below illustrate the scope of the products generated through the process proposed here. EXAMPLES EXAMPLE 1: Chemical analysis of a raw material sample.

[0054] Table 1 shows the results of the chemical analysis obtained by X-ray fluorescence (XRF) of each of the components used to prepare a pre-processing mixture according to the present invention. The sodium source used has a purity above 98% and the activator dosage was based on the amount of Na2O. Table 1: Chemical analysis by XRF of raw material sample. EXAMPLE 2: Chemical analysis of activator samples.

[0055] Three samples of concentrated silico-zeolitic activators were obtained through the process of the present invention. Table 2 shows the mass proportions of the components used to prepare the pre-processing mixture. Table 2: Composition of the pre-processing mixture.

[0056] Table 3 shows the results of the chemical analysis obtained by X-ray fluorescence of each of the three concentrated silico-zeolitic activators obtained by means of the process of the present invention. Table 3: Chemical analysis by XRF of activator samples.

[0057] It is observed that the chemical compositions of the activators obtained were consistent with the mass proportions of the components used to prepare the pre-processing mixture. EXAMPLE 3: Quantification of the mineral phases of activator samples.

[0058] Table 4 shows the quantitative results concerning the mineral phases identified in each of three concentrated silico-zeolitic activators obtained through the process of the present invention, which were performed using X-ray diffraction equipment and XRD analysis software.

[0059] It can be seen that as an alumina source was added to replace the majority silica source in the pre-processing mixture, more zeolitic mineral phases were formed. Similarly, the lower the amount of alumina in the system, the greater the amount of sodium silicate formed in each activator.

[0060] Figure 4 illustrates the identification of the mineral phases, by means of X-ray diffraction, of the three samples of activators obtained by means of the process of the present invention. Table 4: Quantitative analysis of mineral phases of activator samples.

[0061] The following examples refer to the calorimetric analysis and mechanical performance under compression of mortars containing cement activated with each of the three activator samples obtained through the process of the present invention. In this context, it was decided to analyze different levels of the silico-zeolitic activator (15% w / w, 20% w / w, and 25% w / w) in the composition of the alkali-activated cement. This cement was obtained using blast furnace slag as a precursor. Table 5 shows the formulations of the analyzed cements. Table 5: Cement formulation. EXAMPLE 4: Mechanical performance analysis: compressive strength.

[0062] Figures 5, 6, and 7 demonstrate, respectively, the compressive strength results of mortars using NBR 7215, containing 15%, 20%, and 25% of the activators obtained through the process of the present invention. It can be observed that, by controlling the amount of silico-zeolitic activator in the system, it is possible to achieve different strength classes at 28 days, ranging from classes aimed at simpler artifacts (around 30 MPa) to classes for more elaborate constructions (around 50 MPa).

[0063] Furthermore, depending on the application and the need for a more or less cohesive matrix—that is, one that performs better from a durability standpoint—activators with a higher zeolite content can be chosen, so that the zeolite can dissolve over time and promote greater compactness in the matrix. EXAMPLE 5: Calorimetric analysis.

[0064] Figures 8a / 8b, 9a / 9b, and 10a / 10b demonstrate, respectively, the results of accumulated heat over time and heat flux over time of mortars containing 15%, 20%, and 25% of the activators obtained through the process of the present invention, using the calorimetry technique that measures the heat flux and accumulated heat of the alkali-activated cement with a water / cement ratio = 0.5 over time. Tables 6, 7, and 8 below present the quantitative data relating, respectively, to Figures 8a / 8b, 9a / 9b, and 10a / 10b.

[0065] It is observed that these results were consistent with the mechanical performance results, which show that the silica- The zeolite is most effective after three days of curing at room temperature. Furthermore, through the total heat and heat flux data, it is possible to observe that within 75 hours, the activators containing larger amounts of sodium silicate and smaller amounts of zeolite significantly outperform each other. However, after 75 hours, the difference between the activators is more subtle. Table 6: Calorimetry results for cements with 15% silico-zeolitic activator and 85% blast furnace slag. Table 7: Calorimetry results for cements with 20% silico-zeolitic activator and 80% blast furnace slag. Table 8: Calorimetry results for cements with 25% silico-zeolitic activator and 75% blast furnace slag.

[0066] The examples demonstrate that the proposed process, as well as the activators obtained and their use for alkali-activated cements, consist of effective and more sustainable alternatives compared to the state of the art.

Claims

CLAIMS 1. Process for obtaining concentrated silico-zeolitic activator, characterized by the fact that it comprises the following steps: - homogenization of a major source of silica (SiO2), a source of alumina (Al2O3) and a source of sodium (Na2O) to obtain a pre-processing mixture, in which the alumina source can additionally contribute as a source of silica; - heat treatment of the pre-processing mixture at a temperature between about 400ºC and about 600ºC; - cooling.

2. Process according to claim 1, characterized by the fact that the major source of SiO2 is predominantly quartzose, consisting of sand of any origin or quartzose ore, with a SiO2 content> 90%; the sodium source (Na2O) consists of granulated or flaky NaOH; and the source of Al2O3 consists of kaolinitic waste from intrusive rocks, decomposed mafic rocks, friable schists, among others. 3.Process according to claim 1, characterized in that the combination of materials, after heat treatment, must consist of a chemical composition of about 25% to about 40% sodium (Na2O), from about 5% to about 15% alumina (Al2O3) and from about 45% to about 70% silica (SiO2).

4. Process according to claim 1, characterized in that the heat treatment step is carried out in a static or rotary furnace, at a temperature between about 400ºC and about 600ºC and a residence time of about 45 min to about 1 hour (in a rotary furnace) or about 3 hours (in a static furnace).

5. Process according to claim 1, characterized in that it additionally comprises a step of agglomerating the pre-mixture. processing prior to heat treatment.

6. Process according to claim 5, characterized in that the agglomeration step consists of a pelletizing step.

7. Process according to claim 5 or 6, characterized in that the agglomeration step is carried out in pelletizing discs, pelletizing drums or any other equipment that allows rotation control (and, therefore, agglomeration), using water as a binder in an amount between about 13% and about 15% in relation to the total mass of solids.

8. Process according to claim 7, characterized in that it comprises, after the agglomeration step, a step of drying the agglomerates at a temperature between about 40°C and about 100°C.

9. Concentrated silico-zeolitic activator, characterized in that it is obtained by means of the process as defined in claim 1. 10.Concentrated silicozeolitic activator according to claim 9, characterized in that it is solid, in powder form.

11. Concentrated silicozeolitic activator according to claim 10, characterized in that it has an agglomerated form.

12. Concentrated silicozeolitic activator according to claim 10 or 11, characterized in that it has a pelletized form.

13. Concentrated silicozeolitic activator according to claim 9, characterized in that it is composed of about 25% to about 50% silicate species, about 1% to about 30% zeolite species and about 20% to about 50% amorphous silica or in quartz form.

14. Use of the activator as defined in claim 9, characterized in that it is for alkaline activation in the production of alkali-activated cement. 15.Use, according to claim 14, characterized by the fact that the activator must be ground to a particle size of less than about 75 μm to be combined with a reactive precursor to obtain the alkali-type cement. activated.

16. Use according to claim 14, characterized in that the amount of activator to be used depends on the type of precursor used for the cement, being: – from about 15% w / w to about 25% w / w for cements with blast furnace slag as precursor; – from about 20% w / w to about 30% w / w for cements with blast furnace slag + calcined clays as precursors; and – from about 25% w / w to about 35% w / w for cements with calcined clays or fly ash as precursor.

Images