Carbonized product-containing granules and method for producing them, and use

Abstract

The invention relates to granules for use as building materials or as aggregates in building materials. The invention further relates to methods for producing the granules and the use thereof. The granule according to the invention contains a binder and a carbonized product, the content of the carbonized product in the granules amounting to 30 wt.-% or more, relative to the total weight of the binder and the carbonized product in the granules.

Description

[0001]FRIESE GOEDEN Patentanwälte PartGmbB Widenmayerstraße 49 80538 Munich Our reference: 31778 PWO GO Applicant: Fraunhofer-Gesellschaft eV ─ ... GRANULES AND THEIR PRODUCTION METHOD AND USE ─ ... FIELD OF THE INVENTION The invention relates to granules for use as building materials or as aggregate in building materials. The invention further relates to manufacturing processes for the granules and their use. PRIOR ART The construction industry is an industrial sector with high CO2 emissions. For example, the cement industry is one of the main emitters of greenhouse gases that cause global warming. Worldwide, 4.1 billion tons of cement are produced annually, which contains an average of approximately 60% CaO.This means that the release of carbon dioxide bound in the lime, even with optimal process management, results in emissions of at least three billion tons of CO2, or approximately 6 to 8% of annual CO2 emissions. For example, the production and use of 1 kg of Portland cement releases approximately 0.7 kg of CO2. In order to achieve climate targets and reduce future costs related to CO2 pricing, CO2 emissions in the construction industry should be reduced. One aspect of this is the search for alternative raw materials and substitutes for particularly CO2-intensive building materials. One known possibility is the utilization of carbonizates in building products, whereby CO2 is bound in the form of carbon, allowing the building material to function as a carbon sink.However, the use of carbonisates in building materials is only possible to a limited extent due to their heterogeneous material composition and the resulting irregular properties. Carbonisates from different sources or different manufacturing processes also have different properties, which is why building material formulations must be continually adapted to them. Large-scale industrial use is currently limited because the adaptation or modification of the residual materials (e.g. chemical processing, conditioning, activation) is often complex and uneconomical. However, solutions must be found to incorporate carbonisates into building materials without disadvantages in order to contain the climate effects of the construction industry and at the same time limit the costs due to the expected increase in CO2 pricing. There is therefore a lack of efficient and cost-effective homogenization orModification processes to adjust the properties of the carbonates or to optimize their bonding to the building material matrix and then use this intermediate product in various building materials. US 2020 / 0062646 A1 discloses building materials in which cement, sand, and biochar are mixed and hardened after the addition of water. Alternatively, powdered biochar is mixed with plaster or gypsum and processed into coated or homogeneous pellets that can be used as filler for drywall. The disadvantage of this is that only very small amounts of biochar could be absorbed using the disclosed processes (approx. 6 g per 0.1 m²). 2Wall panel). Alternatively, just under 1.5 wt.% biochar in the dry mass could be achieved during mortar production by replacing a small portion of sand with biochar. However, the biochar used here had to be ground first after pyrolysis, which represents an additional, energy-intensive step in which additional energy is consumed and thus also results in further CO2 release. The high specific surface area of ​​the biochar is further increased by grinding, allowing it to adsorb more moisture. This has a strong influence on the workability of the mortar mixture, which is why superplasticizers had to be added to the mortar mixture to compensate.In addition, the exact water requirement of the granules described in US 2020 / 0062646 A1 is initially unknown, depending on the origin of the carbonates, and requires coordination with the water content in a mortar mixture. The prior art therefore presents a problem. BRIEF DESCRIPTION OF THE INVENTION A granule according to claim 1, a method according to claim 11, and a use according to claim 14 are described below. Advantageous developments of the invention can be found in the subclaims. In one embodiment, the invention can provide granules comprising binder and carbonate, and wherein the carbonate content in the granules is 20 wt. % or more, based on the total weight of the binder and the carbonate in the granule.It has been found that by mixing binder and carbonizate in granulate form, homogeneous granulate compositions can be easily provided that are suitable for further use in construction. In one embodiment of the present invention, the binder in the granulate is selected from the group consisting of clinker cement, Portland cement, calcium aluminate cement, calcium sulfo-aluminate cement, calcium sulfate (gypsum), calcium oxide, calcium hydroxide, ashes, fly ash, slag, granulated blast furnace slag, alkali metal or alkaline earth metal hydrides, halides, 31778 PWO GO / RM - 4 / 18 - 03.05.2024 oxides, nitrates, sulfates, carbonates, silicates, phosphates, fluorides or their organic derivatives such as alcoholates or acetates, aluminum phosphate compounds, aluminosilicates, clays, calcined clays, kaolin, pozzolans, trass, tuff, organic polymers or combinations thereof.According to the invention, these binders are all suitable for processing with carbonizate to form granules that can then be used in construction. In a further embodiment of the present invention, the carbonizate is selected from the group consisting of biochar, charcoal, pyrolyzed sewage sludge, pyrolyzed paper and / or pyrolyzed cardboard, pyrolyzed digestate, industrial carbon black, and combinations thereof. According to the invention, carbonates from the aforementioned sources or production processes can be used throughout to form granules with binders that can then be used in construction. In a further embodiment of the present invention, the carbonizate content in the granule can be 30% by weight or more, or 40% by weight or more, or 50% by weight or more, or 60% by weight or more, or 65% by weight or more, in each case based on the total weight of the binder and the carbonizate in the granule.According to the invention, depending on the area of ​​application, homogeneous granules can be produced with correspondingly high carbonatation contents. In a further embodiment of the present invention, the granules have a grain size in the range from approximately 0.1 mm to approximately 32 mm or from approximately 0.2 mm to approximately 2 mm or from approximately 1.5 mm to approximately 5 mm or from approximately 5 mm to approximately 10 mm or from approximately 8 mm to approximately 20 mm or from approximately 20 mm to approximately 32 mm or from approximately 0.1 mm to approximately 1.5 mm or from approximately 20 mm to approximately 25 mm or from approximately 25 mm to approximately 32 mm. For a granulate made from a large number of granules according to the invention, an average grain size in the range from 0.1 mm to 32 mm should thus be ensured. Corresponding grain sizes are best suited for use in construction. 31778 PWO GO / RM - 5 / 18 - 03.05.2024 In a further embodiment of the present invention, the granulate is homogeneous.In this context, a granule is referred to as homogeneous if the binder and carbonate are evenly distributed within the granule. In this sense, a uniform distribution exists if the carbonate grains are distributed within a binder matrix in the granule in such a way that there are no regions with carbonate contents that deviate significantly from the average content. In an alternative embodiment of the present invention, a granule can be layered. In this respect, a layered structure is referred to if, for example, the core of the granule consists exclusively of binder or exclusively of carbonate and the core is covered by a layer of the other component. Multiple layer sequences are also considered a layered structure.In particular, depending on the application of the granules, it may be desirable for a binder layer to be present on the surface of the granules. In one embodiment of the present invention, the granules consist essentially of carbonizate and binder. This is the case when, with the exception of water, no other component is present in the granules in an amount of 5% by weight or more. In one embodiment of the present invention, the granules have a loss on ignition, measured according to DIN 18128, of 15% or more. In other embodiments of the present invention, the granules have a loss on ignition, measured according to DIN 18128, of more than 20%, or more than 30%, or more than 50%, or more than 60%, or more than 70%. In particular, this can demonstrate that oxidizable carbon in the form of carbonizate is present in the granules according to the invention and, accordingly, evidence for the binding of CO2 can be provided.31778 PWO GO / RM - 6 / 18 - 03.05.2024 Also part of the present invention is a production process for a granulate comprising granules of the present invention, wherein the production process comprises process steps selected from wet granulation, spray drying, fluidized bed granulation, melt granulation, or combinations thereof. It has been shown that granules according to the invention can be obtained using a variety of production processes. In one embodiment of the production process according to the invention, a first step involves carbonation of biomass, plant material, wood, sewage sludge, paper, cardboard, digestate, or combinations thereof. This step is followed by the addition of a binder, followed directly by granulation.In a further embodiment of the production process according to the invention, grinding and optionally sieving of the carbonate takes place after or during the carbonation, so that the carbonate has a grain size distribution such that d. 80 ≤ 500 μm, or d 80≤ 100 μm. Furthermore, part of the present invention is the use of a granulate containing the granules according to the invention or of a granulate produced by the process according to the invention as an aggregate for building materials, loose-fill insulation, aggregate in dry mortar products, acoustic components, aggregate for acoustic absorbers, addition to crash concrete, dye, aggregate for improving the flow properties in flowable building materials, aggregate for asphalt, filler, plant substrate, aggregate for backing concrete, joint fill, palisades, bedding material, tree discs, granules for dike or dam construction, greening for roofs and facades, catalysts or carrier material for catalysts, filter / sorption, filter material for exhaust gases or liquid waste streams, drying agent, absorber for impurities or pollutants or combinations thereof. It has been shown that the inventive 31778 PWO GO / RM - 7 / 18 - 03.05.2024 granules are widely applicable and suitable for the applications mentioned. BRIEF DESCRIPTION OF THE FIGURES The invention will now be explained in more detail with reference to figures, without limiting the general inventive concept. Fig. 1 shows a selection of composite granules with different grain sizes, obtained according to the exemplary embodiment. Fig. 2 shows a micro-CT image of granules before and after 7 days of water storage; Fig. 3 shows a graphic representation of the compressive strengths after 28 days of the mortar formulations from the following examples; Fig. 4 shows a graphic representation of the flexural tensile strengths after 28 days of the mortar formulations from the following examples. DETAILED DESCRIPTION OF THE INVENTION The invention will now be described in detail with reference to exemplary embodiments thereof and the figure.The present invention proposes a novel solution for the homogenization and adjustment of carbonates so that they can be used on a larger scale in building materials. The aim is to use granulation to produce a homogeneous product for recycling in the form of CO2-negative composite granules from heterogeneous starting materials. 31778 PWO GO / RM - 8 / 18 - 03.05.2024 This goal is achieved by combining preferably mineral materials (such as cement, quicklime, granulated blast furnace slag, fly ash, limestone, kaolin, clay, etc.) with one or more carbonates. This makes it possible to create a homogeneous product whose interaction shell can be adapted to the corresponding building material matrix. The combination is carried out by granulation. The granules, on the other hand, have a smaller surface area than pure coal particles and therefore a lower water requirement.Their use in mortar leads to a less pronounced reduction in flow properties in the fresh state compared to pure pyrocoal and thus requires significantly fewer adjustments. The granules according to the invention can basically be used as a sand substitute in mortar or concrete. It is possible to replace natural aggregates with spherically shaped and dimensionally stable granules consisting of cement stone and coal and having adjustable grain sizes with diameters in the range from > 0 to 32 mm. This makes it possible to produce components with almost identical strength to references without substituting natural sand. In different embodiments of the present invention, the granules can be uniformly structured or contain different layer sequences. A wide variety of surface properties can be achieved on the granules through targeted coating during the granulation process (e.g.Hydrophobicity, hydrophilicity, roughness, specific surface, etc.), which can interact in different ways with a binder matrix to define the properties of the entire component. These properties can be individually adjusted during granulation and adapted or optimized to the respective application. Depending on the application, the carbonizate content of the granules according to the invention can be set to 70 wt. % or more 31778 PWO GO / RM - 9 / 18 - 03.05.2024 In some embodiments of the present invention, the granules obtained are emission-free or even CO2-negative in their material-technical CO2 balance and thus have a negative emission effect on a material into which the granules according to the invention are introduced. The granules according to the invention make it possible to process carbonates without restriction for use in building material systems, regardless of their origin.All known variations of carbonate can be used, in particular biochar, charcoal, pyrolyzed sewage sludge, pyrolyzed paper and cardboard, pyrolyzed digestate, industrial carbon black, and combinations thereof. The granules according to the invention make it possible to offset the CO2 emissions of the added components (e.g., mineral binders such as Portland cement) through the carbon content of the carbonate, which is obtained, for example, from biomass through pyrolysis. For example, the production and use of 1 kg of Portland cement releases approximately 0.7 kg of CO2. On the other hand, the production of 1 kg of carbonate with up to 99% carbon binds approximately 3.67 kg of CO. 2.Thus, theoretically, 191 g of carbonizate can offset the CO2 emissions of one kilogram of Portland cement. The binding of CO2 in the granules according to the invention is also demonstrated by a loss on ignition, measured according to DIN 18128, in the range of 15% or higher. Furthermore, it has been found that the granules according to the invention, in contrast to powdered carbonizates, do not emit any coal dust during transport, storage, or handling, thus outweighing the disadvantages regarding occupational health or the risk of explosion. Thus, the granules according to the invention can also be stored in silos and can be more easily conveyed and dosed during filling, packaging, and use. A further advantage of the granules is their moisture-regulating property through reversible water and moisture absorption and release.The capacity can be adjusted by selecting the materials / raw materials, in particular the carbonizates, as well as the process parameters and thus size, density, and porosity. The dimensional stability achieved by the granules according to the invention is a basic prerequisite for further use in various building materials. Due to the water absorption capacity of biochar, volume increases may also occur. Swelling of individual components in building materials is usually associated with difficulties, so that potential swelling of the granules plays a crucial role and must be prevented accordingly. In contrast to free coal, the granules according to the invention prevent swelling to such an extent that they can be used in building materials in accordance with standards. Possible methods for homogenization include wet granulation, spray drying, or alternatively, fluidized bed or melt granulation.In the preferred wet granulation process, a liquid, usually water, is added to the powder mixture discontinuously or continuously during the mixing process. If a binder is used, this can be added as a solid or a liquid. The fluidized bed process is handled in a similar way to wet granulation. In melt granulation, the binder is liquefied by elevated temperatures during granulation, before the resulting granules harden again at ambient temperature. It has been found that the different processes described make carbonates suitable for use in building material systems without restriction, regardless of their origin and production method. It has also been shown that the amount of carbonates used in building materials can no longer be limited based on the material 31778 PWO GO / RM - 11 / 18 - 03.05.2024 properties are limited, thus achieving a higher filler content and maximizing the climate-positive effect. The granules according to the invention can be used in a wide range of applications. These include construction applications, gardening and landscaping, and as functional carrier particles. In the construction sector, the granules according to the invention can be used as an aggregate for building materials, loose-fill insulation, aggregate in dry mortar products, acoustic components, aggregate for acoustic absorbers, additive in crash concrete, dye, aggregate for improving the flow properties of flowable building materials, aggregate for asphalt, or as filler.In gardening and landscaping, the granules according to the invention can be used as plant substrate, aggregate for backing concrete, joint fill, palisades, bedding material, tree discs, granules for dike or dam construction, or in greening roofs and facades. The use of the granules according to the invention as carriers is conceivable, as catalysts or carrier material for catalysts, in filter / sorption systems, as filter material for exhaust gases or liquid waste streams, as drying agents, or as absorbers for contaminants or pollution. Any combinations of the features and / or definitions described herein are also part of the present invention, provided they are not mutually exclusive. The description of the innovation relates to specific embodiments of the innovation with the aim of illustrating them.The person skilled in the art will recognize that further modifications and equivalents of the embodiments described here are possible. Such modifications and equivalents also constitute part of the overall scope of the described innovation. 31778 PWO GO / RM - 12 / 18 - 03.05.2024 EXAMPLE 1 A Portland cement-bonded granulate made from a carbonizate (charcoal with a carbon content of 90–92 wt.%) was produced as follows: 1 kg of Portland cement (42.5 N) was wet-granulated with 2 kg of charcoal in a mixer with the addition of 1.65 kg of water. Depending on time and speed, granules with different grain sizes were obtained, as shown in Fig. 1. Regardless of the grain size of the granules, the material CO2 balance is calculated as follows. 1 kg of cement (OPC) emits approx. 0.7 kg of CO2 and 2 kg of coal (carbonate consists of approx. 91% carbon) binds approx.6.68 kg CO2 – In the balance, with this recipe, based on binder and coal, 5.98 kg CO2 is bound in the form of carbon. Accordingly, approximately 1.99 kg CO2 is bound per kg of granules. In this calculation, the added water was not included in the mass balance. Storage of the resulting granules in water for 7 days showed that the size of the granules remained stable. This is illustrated by Fig. 2. The deviations in the difference image (center) are due to fine particles that moved during storage. EXAMPLE 2 Example 2 concerns the production of mortar formulations with the granules according to the invention. A standard mortar recipe was used to test the effect of partially replacing sand with biochar or the granules according to the invention. The standard mortar formulation (reference example RB1) consisted of 450 g cement, 1350 g sand and 225 g water.In Comparative Examples VB1 and VB2 and Inventive Examples EB1 and EB2, 5 and 10 wt.% sand were replaced with identical masses of coal and inventive granulate, respectively. Table 1 summarizes the mortar compositions of the reference, comparative, and inventive examples (without water). 31778 PWO GO / RM - 13 / 18 - 03.05.2024 Table 1: RB VB1 VB2 EB1 EB2 Cement 450 g 450 g 450 g 450 g 450 g (CEM l 42.5) Sand 1350 g 1282 g 1215 g 1282 g 1215 g Coal 0 68 g 135 g 0 0 (L7307) Granules 0 0 0 68 g 135 g (Example 1) The manufactured recipes were used in mortar prisms and tested 28 days after their production for their compressive strength (DF) and flexural tensile strength (BZF) in accordance with DIN EN 196-1. In addition, the CO2 balances of the recipes were calculated. The results are shown in Table 2 and Fig. 3 and 4.For the calculation of the CO2 footprint, values ​​of +0.7 kg CO2 per kg of cement, 3.34 kg CO2 per kg of coal, and -1.99 kg CO2 per kg of aggregate were assumed. Sand is assumed to be CO2-neutral. Table 2: RB VB1 VB2 EB1 EB2 - CO2 balance 0.315 kg -0.09 kg 0.18 kg 0.046 kg 0.135 kg Volume 1.242 L 1.581 L 1.830 L 1.384 L 1.475 L CO2 balance 3 253.6 kg 56.9 kg -73.8 kg 130.1 kg 31.2 kg per m DF 46 MPa 15 MPa 12 MPa 36 MPa 33.5 MPa BZF 10 MPa 4 MPa 3 MPa 8 MPa 7 MPa The substitution of sand with either granules or pure coal leads to a reduction in the compressive and flexural tensile strength in the test prisms made of mortar compared to the reference with pure quartz sand. Compared to the addition of granules, the addition of pure coal resulted in significantly lower compressive and flexural strengths, as well as a significantly greater reduction in processability. To adjust the flow properties, both 31778 PWO GO / RM - 14 / 18 - 03.05.2024, additional water was added to both the batches containing granules and pure coal. This resulted in a comparatively higher w / c ratio in the formulation, which ultimately led to a decrease in the strength of the mortar prisms. In the formulations containing loose coal as a sand substitute, workability was significantly poorer than with mortar containing granules, which is why the water requirement was significantly higher in these. This explains the comparatively significantly lower strength values. By partially replacing sand with granules, the CO2 footprint of the mortar formulations was drastically improved, while the losses in mechanical properties remained within an acceptable range. In contrast, the use of coal achieved an even better CO2 footprint, but the resulting mortar formulations had unacceptable mechanical properties.Due to the lower bulk density of the granules compared to the coal, the resulting mortar formulations also have a lower density. Of course, the invention is not limited to the embodiments shown. The above description is therefore not to be regarded as restrictive, but as explanatory. The following claims are to be understood in such a way that a named feature is present in at least one embodiment of the invention. This does not exclude the presence of further features. The following claims are not to be understood in such a way that a named feature or a named combination of features is present in every embodiment of the invention. Where the claims and the above description define "first" and "second" embodiments, this designation serves to distinguish between two similar embodiments without establishing a priority.

Claims

Claims 1. Granules comprising binder and carbonate, wherein the carbonate content in the granules is 30 wt.% or more, based on the total weight of the binder and the carbonate in the granules.

2. Granules according to claim 1, wherein the binder is selected from the group consisting of clinker cement, Portland cement, calcium aluminate cement, calcium sulfoaluminate cement, calcium sulfate (gypsum), calcium oxide, calcium hydroxide, ashes, fly ash, slag, granulated blast furnace slag, alkali metal or alkaline earth metal hydrides, halides, oxides, nitrates, sulfates, carbonates, silicates, phosphates, fluorides, or their organic derivatives such as alcoholates or acetates, aluminum phosphate compounds, aluminosilicates, clays, calcined clays, kaolin, pozzolans, trass, tuff, organic polymers, or combinations thereof. 3.Granules according to claim 1 or 2, wherein the carbonate is selected from the group consisting of biomass, biochar, charcoal, pyrolyzed sewage sludge, pyrolyzed paper and cardboard, pyrolyzed digestate, carbon black, and combinations thereof.

4. Granules according to one of the preceding claims, wherein the carbonate content in the granules is 40 wt.% or more, or wherein the carbonate content in the granules is 50 wt.% or more, or wherein the carbonate content in the granules is 60 wt.% or more, or wherein the carbonate content in the granules is 65 wt.% or more, in each case based on the total weight of the binder and the carbonate in the granules.

5. Granules according to one of the preceding claims, having a grain size in the range of 0.1 mm to 32 mm.

6. Granules according to one of claims 1 to 5, wherein the granules are homogeneous.

7. Granules according to one of claims 1 to 5, wherein the granules have differently structured layers.

8. Granules according to claim 7, wherein carbonate is present in the core of the granules and binder is present on the surface of the granules.

9. Granules according to one of the preceding claims, consisting essentially of binder and carbonate.

10. Granules according to one of the preceding claims, which have a loss on ignition of 15% or more, measured according to DIN 18128.

11. A production process for granules comprising granules according to any one of the preceding claims, comprising wet granulation, spray drying, fluidized-bed granulation, melt granulation, or combinations thereof. 12.The process according to claim 11, wherein, in a first step, carbonation of plant material, sewage sludge, paper, cardboard, digestate, or combinations thereof is carried out, followed by the addition of a binder, followed by granulation.

13. The process according to claim 12, wherein, after or during the carbonation, grinding and, optionally, a... Sieving of the carbonate is carried out so that the carbonate has a grain size distribution such that the 80 500 μm, or d 80≤ 100 μm.

14. Use of a granulate from any one of claims 1 to 10 or use of a granulate produced by the process from claims 11 to 13 as an aggregate for building materials, loose-fill insulation, aggregate in dry mortar products, acoustic components, aggregate for acoustic absorbers, additive in crash concrete, dye, aggregate for improving the flow properties in flowable building materials, aggregate for asphalt, filler, plant substrate, aggregate for backing concrete, joint fill, palisades, bedding material, tree discs, granules for dike or dam construction, greening for roofs and facades, catalysts or carrier material for catalysts, filter / sorption, filter material for exhaust gases or liquid waste streams, drying agent, absorber for impurities or pollutants or combinations thereof.

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