EP4313901A1

EP4313901A1 - Binder for building materials, method for production thereof and plant for carrying out this method

Info

Publication number: EP4313901A1
Application number: EP22714989.5A
Authority: EP
Inventors: Alf Heidemann; Jörn RICHTER; Michael Larisch; Morten HOLPERT; Georg Bachmann
Original assignee: Eew Energy From Waste GmbH; Heidemann Recycling GmbH
Current assignee: Eew Energy From Waste GmbH; Heidemann Recycling GmbH
Priority date: 2021-04-01
Filing date: 2022-03-28
Publication date: 2024-02-07
Also published as: WO2022207036A1; CA3214015A1; DE102021108322A1

Abstract

The invention relates to a binder for building materials consisting of cement and mineral grinding additives, said grinding additives containing ash of burned refuse, characterized in that, relative to the binder, the ash of burned refuse has a mass fraction of 0.005 to 0.4 and a specific surface area according to Blaine of 1500 cm2/g to 6000 cm2/g. The invention further relates to a method and to a plant for carrying out the method for production of a binder for building materials consisting of cement and mineral grinding additives, said grinding additives containing ash of burned refuse, said method being characterised by the steps of: preparing the ash of burned refuse provided as grinding additive by separating out the fraction having a particle size less than 1 mm and the oversize particles having a particle size greater than 40 mm; pre-crushing the ash of burned refuse which has been freed from the undersize particles and the oversize particles; removing ferrous and non-ferrous metals; further crushing of the pre-crushed ash of burned refuse which has been substantially freed from metals, in order to achieve a specific surface area according to Blaine from 1500 cm2/g to 6000 cm2/g, the ash of burned refuse prepared in this way being added to the cement before and/or after the further crushing of the ash of burned refuse which has been pre-crushed and substantially freed from metals.

Description

DESCRIPTION

Binding agents for building materials, manufacturing process therefor and installation for carrying out this process

The invention relates to a binder for building materials consisting of cement and mineral grinding materials, the grinding materials containing waste incineration ash. The invention also relates to a method for producing such a binder and a plant for carrying out this production method.

Cement or a binder containing cement is a hydraulically hardening building material consisting of a finely divided mixture of non-metallic and inorganic components. Cement can be produced by jointly grinding a Portland cement clinker burned during sintering in a rotary kiln with other main and secondary components or by mixing separately finely ground main and secondary components and adding a setting regulator such as gypsum and/or anhydrite. Cement is mainly used as a binder for mortar and concrete. When fresh, after the addition of water, cement hardens both in air and under water. In the fresh state there is any formability of the mixture with sand and coarser rock grains laid out with a certain grain size distribution. In the hardened state, the cement stone connects this grain structure. The main properties of cement, such as the timing of setting and hardening, strength properties and chemical and physical resistance are known to depend on the chemical and mineralogical composition of the raw materials, the ash from the fuels used in the sintering process in the rotary kiln, the proportion of the ground or mixed main and Secondary components and the optimal coordination of the setting regulator used, such as gypsum and/or anhydrite. The fineness of grinding and the grain size distribution of its main components are also decisive for the most important properties of the cement or cementitious binder produced in this way. According to DIN EN 196-6, the grinding fineness can be described by the mass-related Blaine surface area using air permeability measurements in cm ² /g. Cements with a grinding fineness of less than 2800 cm ² /g are considered coarse, those with more than 4000 cm ² /g are fine. Cements with a Blaine value of 2800 - 4000 cm ² /g have a medium fineness, while very fine cements are between 5000 cm ² /g and 7000 cm ² /g. All standardized types of cement and their composition are listed according to DIN EN 197-1. The types of cement most commonly used in the cement industry are Portland cement, Portland slag cement and blast furnace cement. According to the standard, Portland cement has the abbreviation CEM I. With Portland cement, it is known to replace part of the Portland cement clinker with blast furnace slag. In the production of pig iron from the gangue of the ore, coke ash and aggregates, blast furnace slag is a by-product, initially as blast furnace slag. Rapid cooling of the liquid slag with water to temperatures < 100 °C produces glassy solidified blast furnace slag with grain sizes of up to a few mm. Granulated blast furnace slag is a latently hydraulic substance that hardens hydraulically like cement in a technically usable time using an activator such as Ca(OH)2, CaSC> ₄ etc.

In the conventional cements containing blastfurnace slag, the blastfurnace slag is usually ground to a fineness of 3500 to 4500 cm ² /g according to Blaine. However, higher grinding finenesses of up to more than 6000 cm ² /g but also grinding finenesses of 1600 cm ² /g to 2500 cm ² /g according to Blaine are known, with the coarser variant also being referred to as blast furnace slag. Such a Portland cement containing blastfurnace slag is also referred to as Portland slag cement and according to the standard has the abbreviation CEM II. With a blastfurnace slag content of 6 to 20%, an A is added to the abbreviation and with a proportion of 21 to 35% the letter B is added. Blast furnace cements can have a blast furnace slag content of 36 to 95% and have the abbreviation CEM III according to the standard. Here, too, the letters A, B or C are added depending on the blast furnace slag content. It is also common to characterize a cement by its strength class, such as 32.5, 42.5 and 52.5. If a cement has a high early strength, it is also given the abbreviation R. If it has a normal early strength, it is also given the abbreviation N.

In terms of process technology, Portland slag cements and blast furnace cements can basically be produced both by grinding the main components together and by mixing finely divided main components that are added separately.

Waste incineration bottom ash (slag) is produced in addition to filter dust and salts during the thermal recycling of waste from waste incineration plants. After incineration, they are discharged from the combustion chamber via a slag remover, usually a wet slag remover. Slag mainly consists of non-combustible minerals, metals, salts, sulphates and a small proportion of unburned matter. They also contain not inconsiderable amounts of heavy metals and other trace elements, which make it difficult to use them economically without further processing. Therefore, slag or ashes are usually further processed for further use, whereby ferrous and non-ferrous metals as well as unburned material are separated. The mineral fraction can be treated accordingly by sieving, air classification, magnetic separation, eddy current separation, crushing and aging after dry processing or by wet processing through hydraulic separation of salts and sand separation.

According to a draft ordinance for the introduction of a substitute building material ordinance, for the revision of the Federal Soil Protection and Contaminated Sites Ordinance and for the amendment of the Landfill Ordinance and the Commercial Waste Ordinance of November 6th, 2020 published by the Federal Ministry for the Environment, Nature Conservation, Nuclear Safety and Consumer Protection § 2 No. 28, household waste incineration ash is classified as “Prepared and aged bottom ash and bottom ash from plants incinerating household and similar commercial and industrial waste, as well as waste from private and public facilities”. Correspondingly, the term waste incineration ash (abbreviated: MVA) is used in the present application, and it is often used synonymously in other sources the term incineration bottom ash is used. The household waste incineration bottom ash (HMVA) or synonymously household waste incineration slag (HMVS) is processed bottom ash or grate waste that is produced during the incineration of household waste/municipal waste in waste incineration plants in the combustion chamber of waste incineration plants. This thermal treatment generates energy and reduces the amount of household waste by 75%. This waste incineration ash or synonymous slag is a powdery material with dimensions from 0 mm to over 500 mm. A distinction must be made between waste incineration ash or slag and the filter dust and fly ash that also occurs elsewhere in waste incineration, namely on the flue pipes and filters. For example, between 5 and 6 million tons of household waste incineration ash (household waste incineration slag) are produced in Germany every year. Processed household waste incineration bottom ash is one of the substitute building materials and is subject to the relevant structural and environmental regulations for the relevant areas of application.

Waste incineration bottom ash is not yet permitted as a main or secondary component in cements standardized according to DIN EN 197-1 due to the numerous ingredients that are harmful to the cement, since when used with cement in concrete they lead to undesirable reactions such as cracking, flaking, and leaching of heavy metals when in contact with them of atmospheric elements such as water, nitrous acids, ammonia, carbon dioxide, etc. Methods for immobilizing pollutants from slag, ash and filter dust from waste incineration plants or from other industrial plants by using inorganic, hydraulically active binders based on cement are listed in numerous patents and published documents.

It is known from DE 36 41 786 A1 that by adding inorganic and/or organic binders to slag and/or filter dust from incinerator bottom ash and optionally adding the amount of water required to bring about a mortar-like consistency Mixture is created which, after drying, results in a rock-hard mass, the density of which can be controlled by the proportions of the mixture components, depending on the intended use. The admixtures of a hydraulic binder to the slag are between 5 - 35%, the proportion of slag between 65 - 95%. The hardened mass can be broken up into heaps and dumped. However, it can also be used as a blow backfill underlay or as a frost-proof filling in road construction. There is no reference to fine-particle processing of the incinerator bottom ash in the published application.

DE 10 2004 051 673 A1 describes a method for producing a landfill binder for immobilizing waste containing heavy metals at a landfill, with various ashes, residues and waste products containing pollutants being primarily used as landfill binders. The immobilization of soluble heavy metal compounds from waste is possible and can be carried out in a leach-proof manner through controlled chemical/adsorptive binding to certain mineral phases such as ettringite. Components from the cement industry rich in free lime, such as bypass or fine flour, are used as residues. The landfill binder does not need to add pure cement.

EP 0 934 906 B1 describes a method for improving the transportability, workability and installation ability of a sludge by changing its consistency, in which a calcareous power plant filter ash is added as an additive with a proportion of between 2 and 7% by weight based on the dry mass of the sludge. However, no statement is made about the hydraulic setting of the mixture and a permanent immobilization of pollutants.

DE 196 12 513 A1 describes a binder for immobilizing pollutants in and/or for solidifying soils, soil-like mixtures, sludges, production and other residues, which contains blast furnace meal and fly ash. The blast furnace meal can be material that is also used as a component of commercial blast furnace cements. It is preferably ground blast furnace slag and/or ground slag sand. The fly ash can be made of hard coal and / or Lignite-fired power plants or from fluidized bed furnaces. The binder serves to bind the pollutants by hardening the test specimen. Achievable mechanical strengths are comparable to concrete. The swelling capacity of the fly ash used is absorbed through the use of blast furnace meal. There is no detailed reference to the production and necessary fineness of the incineration bottom ash, e.g. a specifically comparable surface or fineness such as blast furnace slag powder or fly ash, in order to prevent damaging reactions such as swelling, cracking in the shaped bodies in the hardened concrete in advance due to faster reaction processes in the fresh concrete to avoid. The proportion of ash in the recipes is consistently very high.

Furthermore, DE 102017 114 831 A1 discloses a method for processing fly ash by grinding fly ash with a dry-operated agitator ball mill. This refining mechanically activates the fly ash, resulting in an improved fly ash quality that allows Portland pozzolan cements to be made into binders that can even meet cement standards. Furthermore, a plant for the production of cement with at least one first grinding stage consisting of a first mill and a first classifier for grinding cement clinker is described therein. The fly ash is ground to a Blaine fineness of at least 5000 cm ² /g.

In DE 41 01 347 C2, ashes from waste incineration plants are used to produce artificial additives for the construction industry or for use in underground mining and tunnel construction. The ashes contain heavy metals, salts, etc. The ashes are mixed with cement or other organic binders with the addition of water to form agglomerates and harden. 5 to 90% by weight ash is produced with 10 to 95% by weight binder by grinding Portland cement clinker and ash together and then mixing them. There is no indication of the grain size or fineness of the incinerator bottom ash used.

In DE 38 09 938 A1, moldings are produced by pressing a water-containing mixture of fly ash and cement. The mix contains 30 to 70% by weight fly ash, 20 to 50% by weight cement and 0.5 to 1.5 times the weight of the cement of water. This mixture can also contain filter cake from sludge dewatering or slag from waste incineration. Waste incineration slag can be added to the mixture to be compressed at 5 to 30% by weight. There is no indication of the grain size or fineness of the incinerator bottom ash.

AT 286158 B describes a process for the production of steam-hardened molded parts made of concrete, in which, in addition to cement and water, a mixture of 35 to 70% by weight is used as an aggregate in the total composition of fly ash and waste incineration slag, of which 60 to 75% by weight. % should be incineration slag.

Furthermore, EP 2 801 559 B1 shows a method for increasing the latent hydraulic and/or pozzolanic reactivity of materials, in particular of waste and by-products, in which a starting material is used which can also include waste incineration ash, slag and the like. The materials receive a hydrothermal treatment in an autoclave, resulting in an autoclaved product with hydraulic, latent hydraulic or pozzolanic reactivity. The starting materials should be optimized in terms of particle size and particle size distribution. More detailed information on these parameters was not given.

The invention is based on the object of specifying a cement-containing binder which contains incineration ash as additives, with which, despite the added incineration ash, standard-compliant strength properties and strength developments as well as improved application properties are given. Furthermore, the object of the invention is to specify a production method for such a cement-containing binder and a plant for carrying out the production method for the binder.

The fact that the incineration ash on the binder has a mass fraction of 0.005 to 0.4 and a defined Blaine surface area of 1500 cm ² / g to 6000 cm ² / g, the specified mass fraction of cement can be replaced by incinerator ash, which means that there is a significant C0 ₂ saving. It is crucial for the chemical and mineralogical reaction process for the hardening process of the building material, namely mortar or concrete, that the incinerator ash has a Blaine surface area of 1500 cm ² /g to 6000 cm ² /g in order to form the desired reactivity.

The incineration ash preferably has a mass fraction of 0.05 to 0.25 of the binder. A significant proportion, namely at least 5% to a maximum of 25%, of the binder is thus formed from waste incineration ash, so that there is also a corresponding CO ₂ saving. A maximum mass fraction of 25% allows - depending on the composition of the incineration ash - a suitable immobilization of environmentally relevant pollutants, such as heavy metals in the hardened mortar or concrete.

In a further development, the incineration ash has a mass fraction of 0.1 to 0.15 in the binder. A mass fraction of 10 to 15% waste incineration ash provides a still relevant C0 ₂ -saving a nevertheless safe immobilization of any environmentally relevant pollutants contained in the waste incineration ash.

Depending on the origin and thus the individual composition of the incinerator ash, the incinerator ash is to be regarded as a more or less latent hydraulic component, similar to the well-known use of blast furnace slag.

High levels of free lime from the Portland cement clinker or waste incineration ash component lead to the formation of Ca(OH) ₂ during hydration as a stimulator for the hardening process in mortar or concrete. Therefore, the specific surface area of the incinerator bottom ash is important for the chemical and mineralogical reaction process adjust the cement accordingly in the cementitious binder according to the invention. Correspondingly, the incineration bottom ash preferably has a defined Blaine surface area of 2500 cm ² /g to 5000 cm ² /g.

In order to further improve the reactivity of the binder with the incinerator bottom ash additive, the incinerator bottom ash has a defined Blaine surface area of 4000 cm ² /g to 4800 cm ² /g.

In a further development, the binder can contain the additives blast furnace slag, blast furnace slag semolina and/or ground blast furnace slag. Thus, known additives are processed in the binder in the cement production for so-called Portland slag cements or blast furnace cements, which also leads to a CO ₂ saving compared to the use of a binder exclusively made of Portland cement.

If the cement is Portland cement, Portland slag cement, blast furnace cement and/or a slag-containing binder, additional additives, namely cements with the abbreviations OEM II and/or OEM III, are already used and mixed with the incineration bottom ash. This means that high CO ₂ savings are achieved compared to the use of a binder made exclusively from Portland cement with high reactivity of the binder, ie high final strength and cohesion.

For the production process according to the invention of a binder for building materials consisting of cement and mineral grinding materials, the grinding materials containing incineration ash, the proper comminution of the incineration ash with the best possible separation of ferrous and non-ferrous metals is important in order to produce a grinding material suitable as a building material for the cement of mortar or concrete. This is achieved according to the method steps according to claim 8. It is alternatively possible that the prepared incinerator ash as a grinding material before and / or after the last Crushing or grinding process is added to the cement. In the first alternative, the additive is fed together with the cement, for example in a ball mill, to a final joint grinding process in which the two components are also mixed at the same time. In the second alternative, the ready-to-use comminuted additive is mixed into the likewise ready-to-use cement, in particular in a mixer.

Because the pre-crushed incinerator ash, which has been largely freed from metals, is screened after further comminution, unwanted components from the incinerator ash, in particular metals, can be removed even more extensively for the building material use of the binder in concrete or mortar.

If the steps for preparing and crushing the incinerator bottom ash are carried out several times in succession before mixing it into the cement, both the separation of ferrous and non-ferrous metals can be optimized and the desired fineness of the incinerator bottom ash particles can be achieved. A cascaded process further improves the quality of the mineral additives from the incinerator bottom ash.

The arrangement of processing stages known in the recycling industry in the working direction of the binder to be produced according to claim 11 enables the production of an incinerator ash with the required fineness and the separation of ferrous and non-ferrous metals as undesirable components.

The fact that a mixer for mixing the incinerator ash prepared in this way into the cement is arranged behind the material bed or smooth roll crusher in the working direction makes it possible to create the binder consisting of cement and the processed incinerator ash with the desired mass proportions in a homogeneous mixture.

In a further preferred embodiment of the plant for the production of the binding agent, there is a ball mill downstream of the material bed crusher or smooth roll crusher in the working direction arranged for further comminution of the comminuted waste incineration ash, which has been largely freed from metals, in order to achieve a defined Blaine surface area of up to 6000 cm ² /g.

If a circular vibrating screen is installed in the working direction after the material bed or smooth roll crusher but before the ball mill, the smooth roll crusher can separate metals that are deformed into platy layers and still contain them with high separation accuracy.

If an air classifier is additionally arranged after the circular vibrating screen in the working direction, the quality of the separation and thus the usability of the waste incineration ash prepared in this way as a mineral additive in the binder with a possibly higher mass fraction of up to 0.4 can be made possible, since any that may affect the quality of the from the binder resulting building material damaging components can be removed even more reliably.

Eight formulations for a binder according to the invention with associated tables are described below. Two tables are listed for each recipe, the first table lists the components of the binder used, once without incinerator ash and with 0.05, 0.10, 0.15 and/or even 0.31 mass fraction of incinerator ash. The second table in each case lists the respective test results for the parameters of compressive strength after 2 days, 7 days and 28 days and for formulations 7 and 8 after 56 days and for formulations 5 and 6 the water requirement and the start of setting in minutes.

In the eight recipes presented below, a corresponding binder without incinerator ash and with different proportions of incinerator ash is listed. The 13 exemplary embodiments according to the invention relate to formulations for the use of incineration ash with a defined specific surface according to Blaine in Portland slag cement (CEM II) and blast furnace cement (CEM III) in Ash/slag addition levels of 5 wt%, 10 wt%, 15 wt% and

31% by weight. The incinerator ashes with an initial grain size of 0 - 8 mm were dried in the laboratory at 120 °C. The fines < 1 mm were then separated from the original grain size. Only for recipes 7 and 8 was waste incineration ash with a grain size of 0 - 40 mm used. For formulations 1 to 4 and 7 and 8, the grain fraction was reduced in a laboratory mill to a Blaine specific surface area of on average 4300 cm ² /g, for formulation 5 to 6000 cm ² /g and for formulation 6 to 1600 cm ² /g ground and the recipes prepared according to the information. With the binders formulated in this way, mortar test specimens (4 cm x 4 cm x 16 cm prisms) were produced according to DIN EN 196 et seq. and important cement properties such as compressive strength and setting behavior were tested. These mortar test specimens are made from cement mortar, which is mixed from the binder described here, a sand fraction and water. For the sand fraction according to DIN EN 196-1, a standard sand is used with grain sizes between 0.08 and 2.00 mm (0/2). The maximum moisture content of this sand is 0.2%. For the production of 3 mortar prisms (each one has the dimensions 4 cm x 4 cm x 16 cm), 450 grams of the binder according to the application and 225 grams of water (water-cement ratio 0.5) and 1350 grams of this standard sand are used.

Recipe 1 shows the example of a blast furnace cement without the addition of incinerator ash (IR ash) and with the addition of 5% by weight and 15% by weight IR ash, each with a Blaine specific surface area of 4200-4400 cm ² /g , whereby the respective proportions by weight of RDF ash were divided or counted in half between Portland cement clinker and blast furnace slag in the recipe. With regard to the results of the compressive strengths after 2, 7 and 28 days, it should be noted that although they are lower in comparison to the blast furnace cement that has not been mixed with ash, they are still sufficient for the production of a standardized CEM III cement of the compressive strength class 32.5. The processing times, recognizable at the start of solidification, have increased significantly with the increase in the amount of RV ash, which has led to an improved Flow behavior and leads to a longer and more advantageous processing time. The prisms in the illustration show a dense, compact structure inside and are also without any abnormalities beyond the 28-day storage period. There is no swelling and no crack formation on the surfaces and inside the test specimens.

Exemplary embodiment Recipe 1 Blast furnace cement (HOZ) without the addition of MV ash and with the addition of 5% by weight and 15% by weight of MV ash, each with a Blaine specific surface area of 4200-4400 cm ² /g, the respective Weight proportions of RDF ash were introduced into the recipe in equal parts for Portland cement clinker and blast furnace slag.

Test results on mortar samples according to EN 196 ff. for binders according to recipe 1 Recipe 2 shows the example of a Portland slag cement without the addition of incinerator ash (IR ash) and with the addition of 5% by weight and 15% by weight IR ash, each with a Blaine specific surface area of 4200-4400 cm ² /g , whereby the respective proportions by weight of RDF ash were divided or counted in half between Portland cement clinker and blast furnace slag in the recipe. For the results of the compressive strengths after 2, 7 and 28 days, it should be noted that although they are lower in comparison to Portland slag cement that has not been mixed with ash, they are still sufficient for the production of a standardized CEM II cement of the compressive strength class 32.5, as long as the Addition of the MV ash remains at just under 5% by weight. the

Processing times, recognizable from the start of solidification, have increased significantly with the increase in the amount of RV ash, which also leads to improved flow behavior and a longer processing time in this case. The prisms in the illustration show a dense, compact structure inside and are also without any abnormalities beyond the 28-day storage period. There is no swelling and no crack formation on the surfaces or inside the test specimens.

Exemplary embodiment Recipe 2 Portland slag cement (PHZ) without the addition of MV ash and with the addition of 5% by weight and 15% by weight MV ash, each with a Blaine specific surface area of 4200-4400 cm ² /g, the respective Weight proportions of RDF ash were introduced into the recipe in equal parts for Portland cement clinker and blast furnace slag.

Test results on mortar samples according to EN 196 ff. for binders according to recipe 2

Recipe 3 shows the example of a blast furnace cement without the addition of incinerator ash (IR ash) and with the addition of 5% by weight and 15% by weight IR ash, each with a Blaine specific surface area of 4200-4400 cm ² /g , whereby the respective proportions by weight of MV ash were only included in the recipe proportionately against blast furnace slag. The amount of

Portland cement clinker, on the other hand, remains in the original quantity. For the results of the compressive strength after 2, 7 and 28 days, it can be stated that all mixtures are sufficient for the production of a standardized CEM III cement of compressive strength class 32.5. Since the Portland cement clinker component, which is essential for the compressive strength, has not been changed, the compressive strengths are significantly better. The processing times, recognizable at the start of solidification, have increased significantly with the increase in the amount of RV ash, which in turn leads to improved flow behavior and a longer processing time in this case. Exemplary embodiment Recipe 3 blast furnace cement (HOZ) without the addition of MV ash and with the addition of 5% by weight and 15% by weight MV ash, each with a Blaine specific surface area of 4200-4400 cm ² /g, the respective Weight proportions of MV ash were only introduced proportionately against blast furnace slag in the recipe. The amount of Portland cement clinker remains in the original amount.

Test results on mortar samples according to EN 196 ff. for binders according to recipe 3

Recipe 4 shows the example of a Portland slag cement without the addition of incinerator ash (IR ash) and with the addition of 5% by weight and 15% by weight IR ash, each with a Blaine specific surface area of 4200-4400 cm ² /g , whereby the respective proportions by weight of MV ash were only included in the recipe proportionately against blast furnace slag. The amount of Portland cement clinker, on the other hand, remains in the original amount. For the results of the compressive strength after 2, 7 and 28 days, it can be stated that all mixtures are sufficient for the production of a standardized CEM II cement of compressive strength class 32.5. Since the Portland cement clinker component, which is essential for the compressive strength, was not changed, the compressive strengths are significantly better and, for the addition of 5 wt. ash addition. At the early strength level of 2 days, a slight increase of over 1 MPa can even be seen. The processing times, recognizable at the start of solidification, have increased significantly with the increase in the amount of RV ash, which in turn leads to improved flow behavior and a longer processing time in this case.

Exemplary embodiment Recipe 4 Portland slag cement (PHZ) without the addition of MV ash and with the addition of 5% by weight and 15% by weight MV ash, each with a Blaine specific surface area of 4200-4400 cm ² /g, the respective Weight proportions of MV ash were only introduced proportionately against blast furnace slag in the recipe. The amount of Portland cement clinker remains in the original amount.

Test results on mortar samples according to EN 196 ff. for binders according to recipe 4 Recipe 5 shows an example of a blast furnace cement ( ^HOZ ) CEM III/A with an addition of 15 wt .

Test results on mortar samples according to EN 196 ff. for binders according to recipe 5

The test results on mortar samples according to EN 196 ff. showed satisfactory compressive strength. Although they are lower compared to the "zero cement" (without MVA additive in the recipe), the 28d compressive strength of 32.4 MPa is directly at the standard limit for a HOZ CEM III/A 32.5. In addition, the water requirement in the recipes was determined. Despite the high grinding fineness of 6000 cm ² /g for the incinerator, there was only a very small increase from 26% for the "zero cement" to 26.5% for the cement mixed with MVA. An increase in the specific fineness of grinding according to Blaine to 6000 cm ² /g for the incinerator does not lead to a significant increase in the water requirement. This is a very good result with regard to a later application of the binder in the concrete, should a higher fineness of grind be desired for the incinerator. If, for example, the Portland cement clinker component were to be ground to such a high degree of fineness, significantly higher water requirements would be expected, which would immediately have a negative impact on the concrete compressive strength. The processing time increases significantly from 180 minutes for the "zero cement" to 720 minutes for the cement mixed with MVA.

Formulation 6 shows an example of a Portland granulated cement (PHZ) with an addition of 31% by weight MVA with a Blaine specific surface area of 1600 cm ² /g, the proportion by weight of the MVA being completely replaced by blast furnace slag in the formulation. In addition, in a further formulation, 15% by weight of slag sand was replaced by MVA with a Blaine specific surface area of 1600 cm ² /g.

Test results on mortar samples according to EN 196 ff. for binders according to recipe 6

The test results on mortar samples according to EN 196 et seq. showed significantly lower compressive strengths compared to "zero cement". The early strength values were only half as high. The generally lower compressive strengths are due to the complete replacement of blast furnace slag by the incinerator for this type of binder. In addition, the water requirement increases significantly from 25% for the "zero cement" to 29.5% for the cement mixed with waste incinerators.

The processing time also increases sharply from 215 minutes to 795 minutes.

However, the ratios improve if only 15% by weight MVA instead of 31% by weight MVA are used in the recipe. This is through that

Example of the recipe 7 shown.

Portland slag cement (PHZ) example formulation ⁶ (last column): addition of 15 wt. The compressive strengths improve significantly compared to the results with complete replacement of the blast furnace slag by incinerator. The processing time is also slightly shorter at 560 minutes, but the water requirement does not change.

Accordingly, the amount of MVA added to the binders examined should ideally not exceed a value of 15% by weight to achieve acceptable compressive strength and processing times. For the production of special application-related binders such as landfill binders, higher incinerator inputs in the recipes are also conceivable. These examples should then be checked for possible uses in each individual case.

For a binder based on PHZ, a specific Blaine fineness of 2000-3000 cm ² /g could also be sufficient for the incinerator in order to obtain acceptable compressive strengths. However, Blaine values of around 1600 cm ² /g could also work here, depending on the intended use of the binder, for example with soil mortar and/or landfill binders.

For the tests with HOZ in particular, an addition of 15 wt. As shown in previous tests, a specific Blaine fineness of 4300 cm ² /g of the MVA is sufficient to achieve acceptable compressive strengths. A further increase in the grinding fineness to 6000 cm ² /g does not result in any significant improvement in the compressive strength.

The following exemplary embodiments were carried out on an initial grain size of 0-40 mm from the waste incineration plant. The MVA was ground to a specific Blaine fineness of 4300 cm ² /g. In addition to the standard compressive strengths of up to 28d, the 56d compressive strength should also be determined this time. It was necessary to check whether there would be a further increase in strength, which would also allow conclusions to be drawn about pozzolanic (similar to fly ash) or latent hydraulic (similar to blast furnace slag) activity of the incinerator.

Two binders were made.

Recipe 7 shows an example of a blast furnace cement ( ^HOZ ) without the addition of MV ash and with an addition of 10 wt the recipe was introduced. The amount of Portland cement clinker remained in the original amount.

With these formulations, the compressive strength test should be extended to 56 days.

Test results on mortar samples according to EN 196 ff. for binders according to recipe 7

Results Example 7: The compressive strengths are generally somewhat lower compared to the “zero cement”, but there is a potential for an increase beyond the period of 28 days. The compressive strength increases from 39 MPa after 28 days to 53.2 MPa after 56 days, an increase of around 35%. However, there is another positive feature. While the increase from 28d to 56d in the "zero cement" is only around 15%, we have at least twice as much growth in the binder made with incinerator and blast furnace slag. This could be an indication of an additional reactive component in the incinerator, which still reacts together with the blastfurnace slag component in the binder. Together with the result from recipe 8 (see below), this would be a first indication that the higher the proportion of blastfurnace slag in the binder with the same amount of incinerator added, the more more reactive is the final strength development in the strength period considered.

The processing times are slightly longer compared to "zero cement" (this is known), but are within the usual normal range. The water requirement is about 1.5% higher.

Recipe 8 shows an example of a Portland slag cement (PHZ) without the addition of MV ash and with an addition of ¹⁰ wt the recipe was introduced. The amount of Portland cement clinker remained in the original amount.

Test results on mortar samples according to EN 196 ff. for binders according to recipe 8

Results Example 8: Compared to the "zero cement", the compressive strengths are clearly lower when using the incinerator, but there is also a reasonable potential for increase in this binder, which can be seen in the 56d value. Since there was an increase from 28d to 56d with almost 20% growth (from 36.1 MPa to 43 MPa), the question arises here as to whether this was caused by additional reactivity of the incinerator. If you look at the increase for the "zero cement" for the test period (from 50.3 MPa to 62.6 MPa), we have an increase of approx. 22%. It can be assumed that the additional effect for the 56d in this case was probably caused somewhat more strongly by the blast furnace slag content. But 10% of the blast furnace slag was replaced by MVA and the rate of increase in strength from 28d to 56d was not negatively affected. A difference of 2% in the results is also still in the error tolerance of the compressive strength determination. The processing time is slightly longer than that of "zero cement" (this is known), but is within the normal range. The water requirement for this binder is only 0.5% higher.

A cementitious binder according to the invention can be produced using conventional mixing systems, for example using a mixing system for mixing Portland cement and ground blast furnace slag to produce a

Portland slag cement or blast furnace cement as "pre-cement", in which the MV ash with a defined specific surface according to Blaine is then added. Alternatively, a conventional grinding plant can be used to produce fine or ultra-fine cements. In this, for example, Portland cement clinker can be pre-ground to a clinker powder and finish-ground together with an MV ash with a defined specific surface area according to Blaine and a finely divided setting regulator (eg gypsum and/or anhydrite), for example in a continuous ball mill. With this The MV ash can also be pre-ground to a defined specific surface according to Blaine in a ball mill and then mixed with the above-mentioned "pre-cement" via a mixing plant.

Alternatively, the cement-containing binder according to the invention can also be produced with a two-stage grinding plant for Portland cements consisting of a high-pressure roller mill, which is followed by a ball mill as a continuous mill. The high pressure roller mill grinds Portland cement clinker and blast furnace slag together, with this premix being stored in appropriate intermediate silos and conveyed from there to the ball mill. The MV ash produced to a defined specific surface according to Blaine is then conveyed into the ball mill together with the “premix” and a setting regulator (gypsum and/or anhydrite) and ground to a cement or cement-containing binder according to the invention.

Waste incineration ash (waste incineration slag), for example with an initial grain size of 0 - 8 mm, is first separated from its fine fraction < 1 mm from the original grain size by sieving. The grain fraction, here 1-8 mm, is ground to a defined specific Blaine surface area of 4200-4400 cm ² /g (on average 4300 cm ² /g). A conventional grinding plant such as a ball mill for the production of fine or ultra-fine cements can be used for this purpose. Alternatively, a two-stage grinding plant, which consists of a high-pressure roller mill with a downstream ball mill, can also be used. Waste incineration bottom ash with a grain size > 8 mm can be pre-crushed on the high pressure roller mill and finally ground in a downstream ball mill. Depending on the result of the chemical and mineralogical analysis, the resulting fine fraction < 1 mm can either be separated or used for further processing to a defined specific surface according to Blaine. The separation depends on the presence of environmentally relevant pollutants such as heavy metals, depending on the subsequent use of the cementitious binder according to the invention. The binder can be used, for example, as a landfill binder, for the production of concrete and concrete products, such as paving stones, or masonry mortar. For example, for 1 m ³ normal concrete with a density of 2400 kg/m ³ and a water-cement ratio of 0.5, 480 kg of the binder according to the application, 1920 kg of gravel with 240 l of water are used. The mixing ratio of gravel and the binder described here should be around 4:1 to achieve an average strength class of C20/25, i.e. 4 units of gravel, 1 unit of the binder and 0.5 unit of water. Of course, depending on the type and intended use of the concrete to be produced, the amount of binder to be used must be adjusted.

Furthermore, an exemplary embodiment of a system for carrying out the production method for the binder is described in detail with reference to the attached figure.

It shows:

1 shows a flow chart with the system components in a schematic view.

1 shows a flow chart for the manufacturing process of a binder for building materials consisting of cement and mineral additives, the additives containing waste incineration ash.

The starting material is conventionally processed dry MV slag (incineration ash) 100 with a grain size of 0-40 mm and freed from metals and unburned materials according to the state of the art.

Depending on the moisture content of the material, drying e.g. B. Drying drum may be necessary for optimal screening results.

The material is first freed from material larger than approx. 40 mm and smaller than approx. 1 mm with a combined double-deck screen, a first 3D flip-flow screen 1 with a flip-flop in the lower screen.

The materials that are screened out initially no longer play a role in the process considered here. According to the actually produced quality of the end product, the sieve cuts of the fractions to be separated out can be adjusted with regard to the goal of producing the greatest possible amount of finished material in a defined quality.

The material between about 1 and 40 mm is using vertical crusher 2; especially in material-friendly processing with e.g. B. roll crusher, cone crusher or basin crusher, crushed or, as far as the metals are concerned, opened up, i.e. freed from adhesions and caking.

Thereafter, iron is separated by means of a suitable, first FE separator 3, in particular one or more overbelt magnets.

This is followed by further screening using a triple-deck screen, a second 3D flip-flow screen 4. In the upper deck, a square mesh or a 3D screen of approx. 10 mm is used to separate out oversize particles, mainly metals - and there in particular V2A. This material is processed in a separate process and the slag content is preferably fed back into production.

The grain sizes of approx. 0-2 mm, approx. 2-5 mm and approx. 5-10 mm produced via flip-wave screening are run in parallel to three non-ferrous separators 51, 52, 53 to separate further metals. It may be necessary to cascade the non-ferrous separator and use two non-ferrous separators for each particle size range. The screen cuts used are optimized according to the grading curve that actually occurs during the crushing process, i.e. shifted in such a way that the non-ferrous separators achieve optimal utilization with regard to the target of maximum throughput with the setting of a defined maximum metal content.

The grain sizes from the first non-ferrous separators 51 and second non-ferrous separators 52 of, for example, 2-10 mm, which have been brought together again, are fed back to the vertical crusher 2 . The fine material, currently 0-2 mm, from the third NE separator 53 is fed into a roll crusher 6 . Alternatively, the granules can also be brought together from all three NE separators 51, 52, 53 and fed to the roller crusher 6. Two roll crushers can also be arranged one behind the other, with the input material being pre-crushed in a first roll crusher and then broken down to a first final fineness in the second roll crusher. In addition, the dignified residual metals are plated here. In this alternative design, it may be necessary to use suitable screening, e.g. B. with a circular oscillator with, for example, 2 mm screening.

The processing with a circular vibrating screen 7 will take place with the finest possible screen cut (assumed here 0.6 mm) due to the nature of the material.

The coarse-grained material of this sieving is at best discharged from the process because it contains sufficient metal, or is processed using a suitable wind classifier 8 (e.g. zigzag classifier or separating table) with the aim of discharging metals. If necessary, the processed material is inserted before the first FE separator 3, before the roller crusher 6 or before a second FE separator 9.

The need for a second FE separator 9 for FE separation and a fourth NE separator 10 for NE separation depends on the need for further metal removal resulting from the material composition of the heterogeneous waste incineration ash (starting material) 100 .

At this point in the production process, a cut could take place such that the material produced, namely the processed incinerator bottom ash, is either loaded and taken to a cement plant as input material, or is further processed on site.

In both cases, a ball mill 11 is used to produce the cement aggregate in the desired fineness. When the material is delivered for processing in the ball mill 11 of the cement works, it is continuously added according to the recipe into the material flow provided for the grinding process directly in front of the ball mill 11 and the material is mixed with cement in a mixer 12. In the case of delivery of the end product to the cement works the dosed admixture takes place during the manufacture of the end product by means of a mixing plant 12.

Reference List

100 Incinerator Ash (feedstock)

1 first 3D / flip-flow screen

2 vertical crushers

3 first FE separator

4 second 3D / flip-flow screen

51 first non-ferrous separator

52 second NE separator

53 third non-ferrous separator

6 roller crushers

7 circular vibrating screen

8 air classifiers

9 second FE separator

10 fourth non-ferrous separator

11 ball mill

12 mixers

Claims

PATENT CLAIMS

1 . Binding agent for building materials consisting of cement and mineral additives, the additives containing incinerator ash, characterized in that the incinerator ash in the binder has a mass fraction of 0.005 to 0.4 and a defined Blaine surface area of 1500 cm ² /g to 6000 cm ² /g Has.

2. Binder according to claim 1, characterized in that the incineration ash has a mass fraction of 0.05 to 0.25 in the binder.

3. Binder according to claim 2, characterized in that the

Waste incineration ash has a mass fraction of 0.1 to 0.15 in the binder.

4. Binder according to one of the preceding claims, characterized in that the incineration ash has a defined Blaine surface area of 2500 cm ² /g to 5000 cm ² /g.

5. A binder according to claim 4, characterized in that the incineration ash has a defined Blaine surface area of 4000 cm ² /g to 4800 cm ² /g.

6. Binder according to claim 1, characterized in that the

Additives contain blast furnace slag, blast furnace slag semolina and/or ground blast furnace slag.

7. The binder according to claim 1, characterized in that the cement is a Portland cement, a Portland slag cement, a blast furnace cement and/or a slag-containing binder.

8. A method for producing a binder for building materials consisting of cement and mineral additives, the additives containing waste incineration ash, characterized by the steps

- Preparation of the incinerator bottom ash intended as additive by separating the fraction smaller than 1 mm grain size and the coarse grain larger than 40 mm grain size;

- pre-crushing of incinerator bottom ash freed from undersize and oversize;

- Separation of ferrous and non-ferrous metals;

- Further comminution of the pre-comminuted waste incineration ash, largely freed from metals, in order to achieve a defined Blaine surface area of 1500 cm ² /g to 6000 cm ² /g; before and/or after the further comminution of the pre-comminuted waste incineration ash largely freed from metals, the waste incineration ash prepared in this way is mixed into the cement.

9. The method according to claim 8, characterized in that after the further comminution, the pre-comminuted waste incineration ash, largely freed from metals, is screened.

10. The method according to claim 8 or 9, characterized in that the

Steps for preparing and crushing the incineration bottom ash are carried out several times in succession before mixing into the cement.

11. Plant for carrying out the method according to claim 8, in which the following are arranged one after the other in the working direction of the plant: a flip-flop screening machine (1) for preparing the incinerator bottom ash (100) provided as additional grinding material by separating the fraction with a grain size of less than 1 mm and the larger coarse grain 40 mm grain size, a vertical crusher (2) for pre-crushing the waste incineration ash (100) freed from undersize and coarse grain, an overbelt magnetic separator, magnetic rollers and/or drum magnets for separating Fe metals; - An eddy current separation for separating

non-ferrous metals; and a material bed or smooth roll crusher (6) for further crushing the pre-comminuted waste incineration ash (100) largely freed from metals in order to achieve a defined Blaine surface area of greater than 1500 cm ² /g.

12. Plant according to claim 11, characterized in that a mixer (12) for mixing the waste incineration ash (100) prepared in this way into the cement is arranged in the working direction behind the material bed or smooth roll crusher (6).

13. Plant according to claim 11 or 12, characterized in that in

A ball mill (11) for further comminution of the comminuted waste incineration ash (100) largely freed from metals is arranged downstream of the material bed or smooth roll crusher (6) in order to achieve a defined Blaine surface area of up to 6000 cm ² /g.

14. Plant according to claim 13, characterized in that in

Working direction after the material bed or smooth roll crusher (6), but before the ball mill (11) a circular vibrating screen (7) is arranged.

15. Plant according to claim 14, characterized in that in the working direction after the circular vibrating screen (7) an additional air classifier (8) is arranged.