NL2037199B1 - Method for obtaining a cement constituent from a concrete element - Google Patents

Abstract

Title: Method for obtaining a cement constituent from a concrete element Abstract The invention is in the field of concrete. Specifically, the invention is in the field of providing several fractions, in particular a cement constituent, from a concrete element. The invention is further directed to materials for producing concrete and the use of such materials for producing concrete.

Description

P136273NL00

Title: Method for obtaining a cement constituent from a concrete element

The invention is in the field of concrete. Specifically, the invention is in the field of providing several fractions, in particular a cement constituent, from a concrete element. The invention is further directed to materials for producing concrete and the use of such materials for producing concrete.

Concrete is a composite material of aggregates (such as sand, gravel) and paste and a widely used material for z.a. buildings. The paste typically comprises cement and water. This paste coats the surface of the aggregates and hardens due to hydration. For the production of cement several raw materials are needed, such as cement clinker. Cement clinker 1s generally the main reactive binder component for concrete constructions.

However, the production of cement, in particular the production of cement clinker, and accordingly concrete is associated with high CO: emissions.

Therefore efforts have been made to minimize the carbon footprint, such efforts include reducing the clinker content by using clinker replacements. Clinker replacements may for instance be industrial by- products that would otherwise be waste. Examples thereof include gypsum, fly ash, natural pozzolans and calcined clay and other supplementary cementitious materials (SCM). SCM are considered to be materials that contribute to the properties of concrete through hydraulic and/or pozzolanic activity.

One such effort is provided in WO2022/033877. Herein a method for manufacturing concrete parts is described. This method includes minor carbonation of fresh concrete paste.

Another example is given in W02019/115722, where a method for cleaning an exhaust gas from CO: with simultaneous manufacturing of a supplementary cementitious material from recycled concrete fines is described.

Disadvantageously, these methods do not provide for optimal recycling and upcycling of concrete. The methods do not apply to end-of-life concrete. The carbon footprint is still too large and the quality of the obtained materials is insufficient to be interchangeably used with the virgin materials (i.e. the material as originally used in the production of the concrete element).

Examples are also provided to prepare supplementary cementitious materials.

W02022/248179 describes a method comprising hydrothermal treatment of concrete waste and subsequent carbonation of the hydrothermally activated material to provide a supplementary cementitious material.

US2023/0110452 discloses a method for preparing ground carbonated supplementary cementitious material. The method includes adding water to a carbonatable material to form a carbonatable mixture.

The carbonatable mixture is agitated, carbonated and milled. The milled mixture may also be carbonated.

US2023/0023151 describes various method for preparing carbonated supplementary cementitious materials. These include performing semi-wet carbonation, cyclic carbonation, non-slurry carbonation, high temperature carbonation and granular carbonation of a carbonatable material.

The present inventors surprisingly found a method for obtaining a cement constituent from concrete, that overcomes at least part of the above- mentioned drawbacks. In particular, the method allows for obtaining a cement constituent that may be used in the production of cement, in particular the cement constituent may advantageously have pozzolanic and/or hydraulic properties. Further, the method may allow for a minimal carbon footprint, as the produced CO: may be used in a further step of the method. Additionally, the energy consumption is optimized and waste streams are minimized. Each of the resulting products are typically suitable to be used as materials for the production of concrete. Furthermore, the method may advantageously be performed close to the feedstock to minimize transport.

Figure 1 illustrates a schematic overview of a method according to the present invention.

Figure 2 illustrates a schematic overview of a preferred method according to the present invention.

The present invention is directed to a method for obtaining a cement constituent from a concrete element. As illustrated in Figure 1, the method comprises providing a concrete element (1), breaking said concrete element into concrete parts (2). The concrete parts are subjected to a first liberation and separation step to obtain a coarse aggregate fraction (3), a medium fine fraction (4) and a small fine fraction (5). The method further comprises subjecting the medium fine fraction to a second liberation and separation step to obtain a fine aggregate fraction (6) and an ultrafine fraction (7). The method further comprises grinding and optionally carbonating the small fine fraction and the ultrafine fraction to obtain a cement constituent (8). Preferably, the method comprises grinding and carbonation, more preferably the method comprises simultaneous grinding and carbonation.

The concrete element may be provided in any form. For instance, if a building is torn down, the resulting concrete elements may be used as a starting (feed) material for the present method. This concrete element may be or comprise end-of-life concrete. This is a term known in the art to refer to concrete that has reached the end of useful service. For instance, the deterioration of the concrete is beyond the point where repair is impractical or uneconomic. Alternatively, or additionally, the concrete may be a freshly produced concrete. For example, it is common that a truck comprising z.a. ready-mixed concrete is not emptied fully, as this is challenging to achieve.

The ready-mixed concrete may then be diluted (e.g. with water) and poured onto a substrate. The produced concrete may be used as a concrete element for the present method.

It may be appreciated that the concrete element optionally further comprises one or more impurities, such as water and/or residues from demolition waste (e.g. ceramics, glass).

The method further comprises breaking said concrete element into concrete parts. As the concrete element comprises a composite material of aggregates and paste, this breaking typically allows for liberation of some of the aggregates and paste. Conventional methods to break concrete elements into concrete parts are typically based on impact breaking. This generally results in breaking the element in random directions, and accordingly results in concrete parts that are only smaller pieces of the concrete element (and thus not have a structure of the virgin material). Further, conventional methods often result in destroying the material in such a manner that the provided material would not be commercially relevant. It is accordingly preferred that the force for breaking is substantially evenly distributed over the concrete element. This allows for breaking the concrete element and liberation of the material essentially along the natural composition lines and accordingly essentially without destroying the internal structure. The breaking therefore preferably comprises crushing, typically crushing wherein the pressure is applied on two surfaces of the concrete element, such as crushing in a jaw crusher and/or in a cone crusher. In particular, it may be preferred to apply the pressure on two opposite surfaces of the concrete element, e.g. a top surface and a bottom surface.

A jaw crusher is known in the art and commercially available. The concrete element may be placed in between the jaws. By closing the jaws a force is exerted on the concrete element, thereby breaking the concrete element into concrete parts. A cone crusher is also known in the art and commercially available.

The method further comprises subjecting the concrete parts to a first liberation and separation step. This allows for obtaining a coarse aggregate fraction, a medium fine fraction and a small fine fraction. The first liberation and separation step preferably comprises ballistic 5 separation. Ballistic separation may suitably be performed in a ballistic separator, 1n particular in a separation-apparatus as described in

WO2009/123452, which is incorporated herein in its entirety.

Advantageously, such a ballistic separator may also be suitably used for moist materials. This minimizes the requirements for the feed material and accordingly allows for the ability to process a high variation of feed materials, as the method is generally not sensitive to moisture.

It may be appreciated that the present invention is also directed to such a method for liberating and separating of a coarse aggregate fraction, a medium fine fraction and a small fraction from concrete parts.

The coarse aggregate fraction is typically considered a product that may be sold and/or used as a substitute for virgin coarse aggregates used in the production of concrete. The medium fine fraction may further be processed. The method thus further comprises subjecting the medium fine fraction to a second liberation and separation step to obtain a fine aggregate fraction and an ultrafine fraction.

Preferably, the second liberation and separation step comprises mechanical separation. This may be performed in a separator. Typically, the fine aggregate fraction comprises sand, cement hydrate, unreacted cement particles and/or other contaminants and the ultrafine fraction comprises cement hydrates. Generally, the fine aggregate fraction is bound to the ultrafine fraction. As the thermal expansion of the aggregate fraction and the ultrafine fractions are not identical, the ultrafine fraction and the aggregate fraction may be liberated from one another due to stress caused by the difference in expansion. It may be appreciated that liberation of the fine aggregate fraction and the ultrafine fraction may accordingly be achieved by heating the medium fine fraction. Accordingly, it is preferred that the second Liberation and separation step comprises thermo-mechanical separation. Heating may be provided by a flame, such as a flame with a temperature of at least 500 °C, preferably at least 550 °C, such as approximately 600 °C. Even more preferably, the second liberation and separation is performed in a heating air classification system (HAS). A suitable HAS system is described in WO2019/212336A1, which 1s incorporated herein in its entirety. It may be appreciated that the second liberation and separation step may be essentially without adding water.

Generally, the second liberation and separation step results in the formation of a flue gas. This flue gas comprises CO» and may further comprise water vapor. Preferably, the flue gas comprises CO: and water vapor. Further, it may be appreciated that the temperature of the flue gas is sufficiently high to be used for z.a. drying (vide infra).

Preferably, the flue gas comprises up to 25 vol% COz, more preferably up to 20 vol%, such as between 5 - 15 vol% or between 8 — 12 vol%. Most preferably, the flue gas comprises 9 — 10 vol% COs.

Typically, the flue gas comprises 5-25 vol%, preferably 10 — 15 vol%, water vapor.

It may be appreciated that the remainder of the flue gas may comprise nitrogen gas.

As release of COzis undesirable due to its negative impact on the environment, it is preferred that the flue gas is used for carbonation (vide infra). This is illustrated in Figure 2, wherein the flue gas (9) formed in the second liberation and separation step is led to the grinding and carbonation step. Accordingly, beneficially, the present method may allow for internal use of the CO» and does not substantially release CO: into the environment, nor does it need CO: provided from another (external) source.

The present invention is accordingly also directed to such a method for liberating and separating a fine aggregate fraction and an ultrafine fraction from a medium fine fraction.

The fine aggregate fraction is suitable to be sold and used as a substitute material in the production of concrete. The ultrafine fraction and the small fine fraction are further processed. The method therefore further comprises grinding and optional carbonation of the small fine fraction and the ultrafine fraction to obtain a cement constituent. This may be performed in a mill. It may be appreciated that advantageously, the small fine fraction does not necessarily need to be subjected to the second liberation and separation step and may directly be subjected to grinding and optional carbonation. This minimizes the energy consumption.

The ultrafine fraction and the small fines fraction typically comprise hydrated pastes. The BET surface of the ultrafine fraction and/or the small fines fraction is typically between 0.2 — 2 m?/g, preferably between 0.5 — 1 m2/g. It is preferred to activate the ultrafine fraction and the small fine fraction by carbonating the amorphous content while maintaining a relative humidity and/or moisture content in the process environment and/or in the small fine and/or ultrafine fraction itself. Preferably the relative humidity in the process environment is at least 40%, preferably at least 60%, more preferably at least 80%, such as at least 90%. In particular, it is advantageous to have a relative humidity in the range of 50 — 99%, preferably between 60 — 95%, even more preferably between 80 — 90%. This relative humidity is defined the amount of water vapour present in the process environment relative to the amount of water vapour required to achieve saturation at the same temperature and pressure.

Reactivity of the ultrafine fraction and the small fine fraction may be further improved if the grinding and optional carbonation comprises heating. The heating further advantageously allows for the disruption of the hydrated structure, thereby forming a reactive silica alumina gel, reactive silica and/or reactive alumina gel from amorphous phases of the ultrafine fraction and the small fines fraction. Additionally, the heating further increases the process efficiency and enhances the properties of the obtained cement constituent, in particular SCM. The heating is preferably to a temperature of 50 — 200 °C, more preferably 80 — 170 °C, even more preferably 100 — 160 °C, most preferably 130 — 150 °C. This temperature may advantageously be provided by the flue gas. It may be appreciated that the flue gas leaving the thermo-mechanical separator typically has a temperature within this range, therefore essentially no further addition of energy is needed.

Typically, the cement constituent comprises a binder and/or filler.

The specific type of cement constituent is dependent on the starting material. Nonetheless, the person skilled in the art is aware of possible suitable cement constituents. For instance, the cement constituent may comprise a reactive binder. Reactive binder is herein used as a term to describe a material that has hydraulic (z.e. a material that sets and hardens by chemical reaction with water and is capable of doing so under water) or pozzolanic (i.e. a material that needs both water and calcium hydroxide as reactants in order to harden) constituent and may comprise a supplementary cementitious material. Preferably, the binder, in particular the reactive binder, comprises a SCM comprising 15-50 wt% calcium or calcium complexes based on the total weight of the SCM, preferably a SCM with similar or improved properties to e.g. fly ash, slag cement, raw and calcined natural pozzolans, more preferably a SCM in accordance with standard ASTM C1709-22 and/or EN206:2014 type II addition. The cement constituent may alternatively or additionally comprise a filler, preferably a filler comprising an inert material (providing an inert filler), preferably the filler comprises less than 1 wt%, preferably less than 0.5 wt%, more preferably less than 0.1 wt% chloride and/or less than 0.5 wt%, more preferably less than 0.2 wt%, most preferably less than 0.05 wt% sulfur based on the total weight of the filler. It may be particularly advantageous to have an inert filler according to standard EN 12620:2002 + A1:2008, more preferably a EN206:2014 type 1 filler. Inert fillers are also well known in the art and may for instance be a silica fraction (e.g. quartz; SiOz). The (inert) fillers are typically finely divided materials, less than e.g. 70 microns gr less than 63 microns in size, used in concrete in order to improve certain properties or to achieve special properties.

It may be understandable that for the preparation of an (inert) filler, it is often not required to carbonate the small fine fraction and the ultrafine fraction, while for the preparation of a (reactive) binder, this is typically required.

It may further be appreciated that the method for carbonation is not particularly limiting. Preferably, the flue gas originating from the second liberation and separation step is employed for carbonation. This allows for the internal usage of the formed CO:. Favorably, the water content and temperature of the flue gas allow for ideal conditions for carbonation. That is, the flue gas may provide for an optimal balance between keeping the temperature high enough to stay above the dew point and minimize condensation, while the water content allows for good carbonation.

Alternatively or additionally, chemicals may be used for carbonation. Suitable chemicals are for instance carbonic acid and/or dry ice.

It may be appreciated that external CO» may also be employed. However, this would minimize the advantages of the internal usage of the formed

COs. The present invention is also directed to this method for grinding and optional carbonation of a small fine fraction and an ultrafine fraction to obtain a cement constituent.

Each of the fractions typically individually have a different size.

These sizes are typically determined by the desired application and/or the apparatuses used for the subsequent method steps. The sizes of each individual fraction may easily be changed by adjusting one or more parameters (or settings) during the method. For instance, the rotor speed and/or the pressure of the airknife of the ballistic separator may be adjusted and/or the grinding settings and/or residence time in the mill may be adjusted to provide smaller or larger cement constituents.

The apparatuses used for the method steps may each have requirements for the size. For instance, the ballistic separator may not be suitable for large concrete parts. This could potentially damage the ballistic separator. To ensure that no larger particles enter the ballistic separator, a safety screen or filter may be employed.

The concrete parts may have a d90 size of less than 100 mm. The coarse aggregate fraction typically comprises coarse aggregates having a d90 size in the range of 7 — 20 mm. The medium fine fraction typically comprises medium fines having a d90 size in the range of 3 — 7 mm. The small fine fraction may comprise small fines having a d90 size in the range of less than 3 mm. The fine aggregate fraction may comprise fine aggregates having a d90 size in the range of 0.5 — 7 mm. The ultrafine fraction may comprises ultrafines having a d90 size of less than 0.5 mm.

Alternatively, the concrete parts may have a d90 size of less 50 mm, the coarse aggregate fraction may comprise coarse aggregates having a d90 size in the range of 5 — 15 mm. The medium fine fraction may comprise medium fines having a d90 size in the range of 2 — 5 mm, the small fine fraction may comprise small fines having a d90 size of less than 2 mm. The fine aggregate fraction may comprise fine aggregates having a d90 size in the range of 0.3 — 5 mm. The ultrafine fraction may comprises ultrafines having a d90 size of less than 0.3 mm.

Alternatively, the concrete parts may have a d90 size of less than 20 mm. The coarse aggregate fraction may comprise coarse aggregates having a d90 size in the range of 4 — 12 mm. The medium fine fraction may comprise medium fines having a d90 size in the range of 1 — 4 mm. The small fines fraction may comprise small fines having a d90 size of less than 1 mm. The fine aggregate fraction may comprise fine aggregates having a d90 size in the range of 0.25 — 4 mm. The ultrafine fraction may comprises ultrafines having a d90 size of less than 0.25 mm.

The sizes of each of the individual fractions allow for increased surface area and/or surface reactivity. The surface area may determine the particle packing and/or provide nucleation sites for cementitious reactions to occur. The surface reactivity is particularly interesting for the cement constituent. Namely, the cement constituent sizes allow for a high reactive surface that allows for usage in the production of concrete. Accordingly, the cement constituent has an average particle size d50 of at most 200 um, preferably at most 150 um, more preferably at most 120 um. Typically, the filler has such average particles sizes, while the sizes of the binder may be even smaller. Preferably, the binder has an average particle size d50 of at most 50 um, preferably at most 30 um, more preferably at most 20 um or at most 15 um, such as approximately 10 um. The sizes may even be adjusted such that the cement constituent, in particular the binder, has a d50 size of at most 2 um.

As detailed above, the cement constituent, in particular the filler may comprise a silica fraction. The content thereof, based on the weight of the cement constituent, is dependent on the composition of the starting material, z.e. the concrete element. The silica content is mainly attributed to quartz.

It may be appreciated that, for an SCM, while some silica (or quartz) content is not detrimental (e.g. at most 5 wt% based on the total weight of the SCM) and often present as fine filler material, too much silica negatively affects the properties of the SCM. For instance, the reactivity of the SCM is negatively affected by the presence of silica.

Favorably, the quartz, i.e. most of the silica fraction, is generally harder to grind than the rest of ultrafine fraction and the small fine fraction and may accordingly be easily rejected. Therefore, it may be appreciated that the cement constituent may be further subjected to a purification step.

This purification step allows for separating it into a filler (e.g. the silica fraction) and a binder (e.g. the supplementary cementitious material). Such a purification step may be easily implemented after the grinding and carbonation. For instance, the method may comprise classification of the cement constituent with a certain cut-off particle size. Preferably by air classification. This cut-off value is typically 70 um, preferably 65 um, more preferably 63 um.

To ensure a constant quality of the output, the concrete element, one or each of the fractions and/or cement constituent may be analyzed.

Therefore it is preferred that the method further comprises analysis of the coarse aggregate fraction, the fine aggregate fraction and/or the cement constituent. Further, it may be appreciated that depending on the analysis results, the settings for the method may be adjusted accordingly to ensure that the resulting fractions have the desired properties.

The analysis means are not particularly limiting and may be by any analysis methods known in the art. For instance, one or more sensors (e.g. moisture sensors) may be included to analyze the contents of the individual fractions and/or cement constituent throughout the method.

Alternatively or additionally, an expert in the field may also analyze the fractions and/or cement constituent by eye.

Preferably, the analysis method comprises infra-red (IR) spectroscopy and/or laser-induced breakdown spectroscopy (LIBS). LIBS is a technique known in the art that may be applied to analysis samples both quantitatively and qualitatively. The results of the LIBS may advantageously be used to certify the fractions. For instance, the data may be used to provide RFID tags and as such use it as a certification. LIBS is therefore preferred.

It was found that high yields of the fractions may be obtained.

There 1s minimal to no waste streams associated with the present method.

For instance, 60% of a coarse aggregate fraction, 15% of a fine aggregate fraction and 25% cement constituent, such as supplementary cementitious material, may be obtained based on a starting concrete element.

Another favorable aspect of the present invention is that the method may be easily implemented on a construction and/or demolition site.

The method may thus be (semi-)mobile and as such enables local operation close to the feed material. This minimizes transportation and accordingly costs and CO: emissions.

The pressure during any one and/or each of the individual method steps may be endogenous. In other words, no external pressure is applied and the pressure is at what sets itself.

The invention is further directed to each of the individually liberated fractions. Each of these individual fractions may advantageously have pozzolanic and/or hydraulic proporties.

In particular, the invention is further directed to a coarse aggregate material for producing concrete. This coarse aggregate material has a particle size d50 in the range of 4 — 20 mm, preferably 4 — 16 mm. In addition, the coarse aggregate material has one or more of: - a resistance to crushing between 20 — 60 %, preferably between 30 — 50%; - a bulk density of at least 1400 kg/m3, preferably at least 1600 kg/m3, more preferably at least 1800 kg/m3; - a water absorption of at most 8.0%, preferably at most 6.0%, more preferably at most 4.0%. Preferably, the water absorption is in the range of 2.0 — 8.0%, more preferably in the range of 2.0 — 6.0%, most preferably in the range of 2.0 — 4.0%. The water absorption, resistance to crushing and bulk density may each be independently measured in accordance with

EN12620:2002 + A1:2008.

The coarse aggregate material may comprise a coarse aggregate fraction, typically obtained in the method of the present invention.

The invention is further directed to a fine aggregate material for producing concrete. The fine aggregate material typically comprises a sand and/or sand-like material. The fine aggregate material has a particle size d50 in the range of 0.25 — 5 mm, preferably 0.25 — 4 mm. In addition, the fine aggregate material has: - a bulk density of 1200 - 1600 kg/m3, preferably 1300 - 1600 kg/m3, more preferably 1500 - 1600 kg/m3; and/or

- a water absorption of 1.0 — 9.0%, more preferably 2.0 — 7.0%, more preferably 2.0 — 5.0% Preferably, the water absorption is in the range of 2.0 — 9.0%, more preferably in the range of 2.0 — 7.0%, most preferably in the range of 2.0 — 5.0%. The water absorption, resistance to crushing and bulk density may each be independently measured in accordance with

EN12620:2002 + A1:2008.

The fine aggregate material typically comprises the fine aggregate fraction as liberated by the method according to the present invention.

The invention is further directed to the cement constituent, preferably to a cement constituent comprising a binder, such as an SCM.

Preferably this cement constituent, particular a supplementary cementitious material, is obtainable by the method according to the present invention. The cement constituent typically comprises - less than 10 wt%, preferably less than 8 wt%, more preferably less than 7 wt% SiO; - 10 — 50 wt%, preferably 20 — 50 wt% calcium and/or calcium complexes; and/or - 5 — 30 wt%, preferably 15 — 20 wt% of a reactive silica alumina gel, reactive silica and/or reactive alumina gel.

The invention is further directed to the use of a coarse aggregate material, a fine aggregate material and/or a cement constituent as detailed herein for producing cement and/or concrete. In particular, the cement constituent, more particular a cement constituent comprising an SCM may be used as a substitute of cement in concrete and/or of cement clinker in cement.

For the purpose of clarity and a concise description, features are described herein as part of the same or separate embodiments, however, it will be appreciated that the scope of the invention may include embodiments having combinations of all or some of the features described.

In particular, it will be appreciated that the scope of the invention may also relate to any and each of the method steps individually and independently.

Claims (15)

Conclusions 1. Method for obtaining a cement constituent of a concrete element, said method comprising: - providing a concrete element; - breaking said concrete element into concrete parts; - subjecting the concrete parts to a first liberating and separation step to obtain a coarse aggregate fraction, a medium-fine fraction, and a small-fine fraction; - subjecting the medium-fine fraction to a second liberating and separation step to obtain a fine aggregate fraction and an ultra-fine fraction; - grinding and optionally carbonating the small-fine fraction and the ultra-fine fraction to obtain a cement constituent. 2. A method according to the preceding claim, wherein the method further comprises analysing, preferably by means of laser-induced degradation spectroscopy, the coarse aggregate fraction, the fine aggregate fraction and/or the cement constituent. A method according to any preceding claim, wherein said cement constituent comprises a binder and/or filler, preferably a reactive binder and/or an inert filler, more preferably wherein said cement constituent comprises a silica fraction and/or a supplementary cementitious material, most preferably wherein said cement constituent comprises a supplementary cementitious material. A method according to any preceding claim, wherein said breaking comprises crushing, preferably in a jaw crusher and/or in a cone crusher. 5. A method according to any preceding claim, wherein said first liberating and separating step comprises ballistic separation. 6. A method according to any preceding claim, wherein said concrete parts have a d90 size of less than 100 mm, said coarse aggregate fraction comprises coarse aggregates having a d90 size in the range of 7 - 20 mm, said medium fine fraction comprises medium-sized fine particles having a d90 size in the range of 3 - 7 mm, said small fine fraction comprises small fine particles having a d90 size in the range of less than 3 mm, said fine aggregate fraction comprises fine aggregates having a d90 size in the range of 0.5 - 7 mm, and/or said ultrafine fraction comprises ultrafine particles having a d90 size of less than 0.5 mm. 7. Method according to any of the preceding claims 1-5, wherein said concrete parts have a d90 size of less than 50 mm, said coarse aggregate fraction comprises coarse aggregates having a d90 size in the range of 5 - 15 mm, said medium fine fraction comprises medium-sized fine particles having a d90 size in the range of 2 - 5 mm, said small fine fraction comprises small fine particles having a d90 size of less than 2 mm, said fine aggregate fraction comprises fine aggregates having a d90 size in the range of 0.3 - 5 mm and/or said ultrafine fraction comprises ultrafine particles having a d90 size of less than 0.3 mm. 8. Method according to any of the preceding claims 1-5, wherein said concrete parts have a d90 size of less than 20 mm, said coarse aggregate fraction comprises coarse aggregates having a d90 size in the range of 4 - 12 mm, said medium fine fraction comprises medium-sized fine particles having a d90 size in the range of 1 - 4 mm, said small fine fraction comprises small fine particles having a d90 size of less than 1 mm, said fine aggregate fraction comprises fine aggregates having a d90 size in the range of 0.25 - 4 mm and/or said ultrafine fraction comprises ultrafine particles having a d90 size of less than 0.25 mm. 9. A method according to any preceding claim, wherein said second liberating and separation step comprises mechanical separation, preferably thermo-mechanical separation, and/or wherein said second liberating and separation step comprises forming a flue gas comprising CO2, preferably wherein said method further comprises using said flue gas for said carbonation. A method according to any preceding claim, wherein said milling and optionally carbonation comprises heating, preferably to a temperature of 50 - 200 °C, more preferably 80 - 170 °C, more preferably 100 - 160 °C, most preferably 130 - 150 °C. A method according to any preceding claim, wherein said cement constituent has an average particle size d50 of at most 200 µm, preferably at most 150 µm, more preferably at most 120 µm, preferably wherein said binder has an average particle size of at most 50 µm, preferably at most 30 µm, more preferably at most 20 µm or at most 15 µm, such as about 10 µm. 12. A coarse aggregate material for producing concrete, said coarse aggregate material having a particle size d50 in the range of 4 to 20 mm, preferably 4 to 16 mm, and one or more of: - a crushing strength of between 20 to 60 %, preferably between 30 to 50 %; - a bulk density of at least 1400 kg/m3, preferably at least 1600 kg/m3, more preferably at least 1800 kg/m3; - a water absorption of not more than 8.0%, preferably not more than 6.0%, more preferably not more than 4.0%. 13. A fine aggregate material for producing concrete, said fine aggregate material having a particle size d50 in the range of 0.25 to 5 mm, preferably 0.25 to 4 mm, and one or more of: - a bulk density of 1200 to 1600 kg/m3, preferably 1300 to 1600 kg/m3, more preferably 1500 to 1600 kg/m3; - a water absorption of at most 9.0%, more preferably at most 7.0%, preferably at most 5.0%. 14. A cement constituent for producing concrete comprising: - less than 10 wt.%, preferably less than 8 wt.%, more preferably less than 7 wt.% SiO: (quartz); - 10 — 50% calcium and/or calcium complexes; and/or - 5 — 30% of a reactive aluminium silicate gel, reactive silica gel and/or reactive aluminium gel, preferably wherein the cement constituent is obtainable by the method according to any one of the preceding claims 1 to 11. 15. Use of a coarse granulate material according to claim 12, a fine granulate material according to claim 13 and/or a cement constituent according to claim 14 for the production of cement and/or concrete.