Novel ladle slag-based composition

Abstract

The present invention relates to a composition usable as a binder and / or cement additive for premixed cement products, comprising ladle slag, calcium sulfate, at least one soluble sulfate having a solubility in water at 20°C in the range of 5 g / 100 ml to 90 g / 100 ml, and at least one carboxylic acid having at least two carboxyl groups, wherein the weight percentage of the at least one soluble sulfate is 0.3 to 10% of the total weight of the composition, the percentage ratio of calcium sulfate to ladle slag is 1:2 to 1:6, preferably 1:3 to 1:4, and the carboxylic acid is present in an amount of 0.05% to 3% by weight, preferably 0.17% to 1.5% of the total weight of the composition. The present invention relates to the use of the composition of the present invention as a binder and / or cement additive for premixed cement products, and to premixed cement products and cement containing the same. The present invention also relates to cement-based set products obtained by curing the premixed cement products of the present invention.

Description

Field of the Invention

[0001] The present invention relates to a composition that can be used as a binder for premixed cement-based products and / or as a cement additive. This composition contains ladle slag, calcium sulfate, at least one soluble sulfate, and at least one carboxylic acid having at least two carboxyl groups, and the carboxylic acid is present in an amount of 0.05% to 3% by weight, preferably 0.17% to 1.5% by weight, based on the total weight of the composition. Background of the Invention

[0002] In the metallurgical processes of cast iron and steel production, a large amount of slag is generated. Its composition is closely related to the properties of the raw materials and additives used in the process. Some of this steelmaking slag is initially accumulated in steel mills and sometimes sent to waste treatment plants, while some is used for civil engineering purposes, reducing the burden associated with disposal and reducing the use of natural resources.

[0003] Slag has different physicochemical properties depending on whether it is generated from metallurgical processes such as blast furnaces, oxygen converters, electric arc furnaces, and refining ladle furnaces, and is named based on the furnace in which it is generated.

[0004] Metallurgical slag is classified according to its physicochemical properties based on currently implemented laws (such as the Regulation (EC) No 1907 / 2006 (REACH) on the Registration, Evaluation, Authorization and Restriction of Chemicals, etc.).

[0005] For all types of metallurgical slag, the REACH Iron Slag Consortium (RFSC) has defined the qualitative and quantitative parameters of the substance itself and its eluate under the scientific guidance of the German Iron and Steel Slag Institute (FEhS), enabling the unique property evaluation of slag. Based on this, the research required by the REACH regulation has been developed.

[0006] Slag produced in blast furnaces is called "Glazed Blast Furnace Slag" (GBS, CAS number 65996-69-2, EINECS number 266-002-0) or "Air-Cooled Blast Furnace Slag" (ABS, CAS number 65996-69-2, EINECS number 266-002-0), slag produced in converters is called "Basic Oxygen Furnace Slag" (BOFS, CAS number 91722-09-7, EINECS number 294-409-3); slag obtained from electric furnaces is called "Electric Furnace Slag from Carbon Steel Manufacturing" (EAF-C, CAS number undefined, EINECS number 932-275-6) or "Electric Furnace Slag from Stainless Steel / High Alloy Steel Manufacturing" (EAF-S, CAS number undefined, EINECS number 932-275-6) It is called 932-476-9); and finally, slag obtained from secondary metallurgy, which makes it possible to reach finished products from recycled scrap materials, is called "steelmaking slag" (SMS, CAS number 65996-71-6, EINECS number 266-004-1).

[0007] Some types of slag are commonly used as raw materials in the construction industry and are recognized as by-products. For example, blast furnace slag (GBS and ABS) has always been used in the production of blast furnace slag cement in accordance with the UNI EN 197-1 standard. On the other hand, electric furnace slag (EAF-C) from carbon steel production is widely used as a substitute for natural aggregate in civil engineering and road construction. In both of the above cases, the use of slag reduces the consumption of natural resources and avoids landfill disposal.

[0008] Other types of slag, particularly steelmaking slag (SMS), are more difficult to market as by-products and are often disposed of as waste, posing serious environmental and logistical problems. As of 2021, Italy's steelmaking slag production exceeded 500,000 tons, with an estimated 80% or more ending up in landfills.

[0009] Steelmaking slag - registration documents - ECHA (europa.eu) - or ladle slag, is produced from the secondary processing of steel obtained in the EAF process (IZ Yildrim et al., "Chemical, mineralogical, and morphological properties of steel slag," Advances in Civil Engineering (2011), ID463638, DOI: 10.1155 / 2011 / 463638). It is also called "secondary slag" or "reduced slag" because it is obtained from a secondary metallurgical reduction process (S. Choi et al., "Hydration reactivity of calcium aluminate-based ladle furnace slag powder under various cooling conditions," Cement and Concrete Composites (2020) vol. 114, 103734, https: / / doi.org / 10.1016 / j.cemconcomp.2020.103734).

[0010] Furthermore, in technical terms, slag generated from electric furnaces (EAFs) is defined as "black slag," while slag generated in the steelmaking process outside the electric furnace (secondary process) (ladle slag) is defined as "white slag." In the secondary steelmaking process, iron oxide is reduced to produce steel, but the resulting slag is less contaminated than black slag. As already mentioned, these two types of slag differ in analytical values ​​and product composition.

[0011] Ladle slag is characterized by its low iron oxide content and high calcium oxide and alumina content. However, one problem that makes its use difficult is that when cooled to room temperature, free-crystal oxides such as calcium oxide, magnesium oxide, and iron oxide form internally. These oxides can react with water when the pulverized electric furnace slag is mixed with cement-based mixtures, potentially producing calcium, magnesium, and iron hydroxides that act as expanding agents, degrading cement-based materials containing these oxides (J.-M. Kim et al., Construction and Building Materials (2016) vol. 127, p. 93-101). Furthermore, deformation of the crystal lattice during cooling forms a fine powdery substance, significantly complicating environmental and logistical management.

[0012] To address the above issues, numerous systems and processes have been proposed to simplify the management of ladle slag in an environmentally, safely, and economically sustainable manner, and to convert it into a product that can be reused for other purposes.

[0013] Similar to blast furnace slag, these processes include granulation using water or dry granulation of liquid slag. In this method, the ladle slag is rapidly cooled and converted into glassy or crystalline granules, resulting in hydraulic properties.

[0014] For example, as described in document WO2021156789A1 under the name of Tenova Spa, dry granulation is preferable to water-based granulation whenever possible, as it avoids water consumption and reduces the need for water treatment.

[0015] Ladle slag is rich in calcium aluminate and aluminum oxide and is inherently reactive. In the presence of water, it hydrates and forms a cementitious phase. However, these reaction products are metastable.

[0016] It is known that gypsum can be added to reduce the reactivity of calcium aluminate. In fact, ettringite can be produced by the hydration reaction between gypsum and calcium aluminate.

[0017] Carboxylic acids are also known to be used in compositions usable in the construction industry, particularly for their specific properties as setting retarders and sometimes as fluidizers.

[0018] Setting retarders extend the working time of the mixed product and prolong the time of the plastic phase. This effect often also delays curing. When the curing times of test samples are equivalent (especially short), the mechanical strength when acid is added will be lower than when it is not added.

[0019] Fluidizers can reduce the mixing ratio (water:binder) required for formulation. Reducing the water content in a mixture typically results in a denser matrix, improving mechanical strength.

[0020] However, while carboxylic acids can sometimes have a fluidizing effect, their retarding effect remains dominant. In fact, additives known as fluidizers have evolved, and these mainly consist of high molecular weight functionalized polymers. The latter reduce the mixing ratio without altering the setting and curing times of the binder.

[0021] Therefore, there is a need for a hydraulic bonding mixture containing steelmaking slag that can be used as an additive to premixed cement products and overcome the shortcomings of conventional technologies. Definition

[0022] Unless otherwise specified, all technical terms, notations, and other scientific terms used herein are intended to have meanings commonly understood by those skilled in the art in which this specification relates. In some cases, terms that have commonly understood meanings are defined herein for clarity and / or ease of reference. The inclusion of such definitions herein should not be construed as meanings that are substantially different from those commonly understood in the art.

[0023] The terms "comprising," "having," "including," and "containing" should be understood as unrestricted terms (i.e., "including, but not limited to") and should be considered to include terms such as "consist essentially of," "consisting essentially of," "consist of," or "consisting of."

[0024] All sections shown in the text, figures, and claims of this patent application are understood to include both endpoints of those sections.

[0025] The terms "available," "obtainable," "directly obtainable," and "directly obtainable" are considered synonymous.

[0026] "Premixed cement products" refer to products consisting of binders, inert substances, and additives, formulated to harden when mixed with water. Such products can be used in a wide range of applications in the construction industry, from tiling to concrete repair and interior decoration.

[0027] "The ladle slag" means slag rich in aluminum and calcium and having a low iron oxide content. This ladle slag is generated from the secondary refining process of steel produced in an electric arc furnace. In this secondary refining process, the reduction of iron oxide in the steel is observed.

[0028] According to a preferred embodiment, the ladle slag used in the present invention is deironed before use.

[0029] In one embodiment, the deironed ladle slag used in the present invention is obtained by the method described in the international patent application WO2021156789A1 in the name of Tenova Spa (hereinafter referred to as the "Tenova process").

[0030] According to another preferred embodiment, the deironed ladle slag (preferably obtained by the Tenova method) used in the present invention contains the following components: - Aluminum oxide (Al2O3) 20 - 40%; - Calcium oxide (CaO) 45 - 65%.

[0031] The remaining 100% contains at least one of the following oxides. - Silicon dioxide (SiO2), maximum content 12 - 14% - Magnesium oxide (MgO), maximum content 10 - 15% - Iron oxide (Fe2O3), maximum content 3 - 5% - Sodium oxide (Na2O), maximum content 1 - 2% - Potassium oxide (K2O), maximum content 1 - 2% - Titanium dioxide (TiO2), maximum content 0.3 - 1% - Barium oxide (BaO), maximum content 0.1 - 0.5% - Phosphorus pentoxide (P2O5), maximum content 0.3 - 1% - Sulfur trioxide (SO3), maximum content 3 - 4%. Here, all percentages are weight percentages based on the total weight of the ladle slag.

[0032] In one embodiment, the ladle slag contains the following components: - Aluminum oxide (Al2O3) 20-40% - Calcium oxide (CaO) 45-65% - Magnesium oxide (MgO) 5-10% - Silicon dioxide (SiO2) 8-10% The remaining composition, relative to 100%, consists of other oxides present in trace amounts.

[0033] Preferably, the ladle slag is at least 90% amorphous, more preferably at least 94% amorphous, with the remainder being crystalline. The crystalline phase preferably includes periclase, celite, meienite, quartz, and / or crystalline calcium oxide.

[0034] In a particularly preferred embodiment, the ladle slag is 100% amorphous.

[0035] The term "anhydrous gypsum" refers to anhydrous calcium sulfate.

[0036] The term "gypsum" refers to calcium sulfate dihydrate.

[0037] The term "scaliola" refers to calcium sulfate hemihydrate.

[0038] The term "ettringite" refers to a compound formed when calcium aluminate and calcium sulfate react in the presence of water.

[0039] The terms "setting" and "setting time" are synonymous, referring to the time required for a product to reach a hardened state immediately after manufacturing, after which its behavior changes from plastic to brittle.

[0040] The term "pot life" refers to the period of time a product maintains its fluid and workability properties as it did immediately after manufacturing.

[0041] "Curing time" refers to the time it takes for a product to increase in mechanical strength after it has hardened.

[0042] "Soluble sulfate" refers to sulfates whose solubility, as measured in water at 20°C, is in the range of 5 g / 100 mL to 90 g / 100 mL. Preferably, it is selected from alkali sulfates and alkaline earth sulfates (excluding calcium sulfate and strontium sulfate, and further excluding radioactive alkali sulfates or alkaline earth sulfates (periods 6 and 7)). It also refers to aluminum sulfate.

[0043] Preferably, the soluble sulfate is selected from potassium sulfate, sodium sulfate, lithium sulfate, magnesium sulfate, and aluminum sulfate. More preferably, the soluble sulfate is potassium sulfate.

[0044] JPEG2026511646000002.jpg73158

[0045] "Carboxylic acid" means an acid having at least two carboxyl groups (at least a dicarboxylic acid), preferably a dicarboxylic acid having a hydroxyl group at the α-position relative to the carboxyl group (α-hydroxy acid (AHA)). Preferably, the carboxylic acid is selected from tartaric acid, malic acid, citric acid, lactic acid, succinic acid, oxalic acid and / or malonic acid. Salts of the carboxylic acid, such as sodium salts or potassium salts, can also be used.

[0046] Polymeric carboxylic acids are excluded from the definition of carboxylic acids that have at least two carboxyl groups.

[0047] "Emergency mechanical strength development" means that mechanical strength is developed within 24 hours of the start of mixing of the binding composition and water.

[0048] The abbreviation "CS" stands for compressive strength. [Brief explanation of the drawing]

[0049] Figure 1 is Table 1 relating to Example 1, showing experimental results that support the regulatory ability of potassium sulfate to ettringite formation in the aggregate obtained using the composition according to the present invention.

[0050] Figure 2 is Table 8 for Example 6, showing experimental results that support the ability of tartaric acid to promote primary ettringite formation.

[0051] Figures 3-7 show Tables 12A (potassium sulfate), 12B (sodium sulfate), 12C (lithium sulfate), 12D (magnesium sulfate), and 12E (aluminum sulfate) for Example 9, respectively, and illustrate experimental results that support the ability of soluble sulfates to control ettringite formation in the aggregates obtained using the composition of the present invention.

[0052] Figures 8-10 show Tables 14A (tartaric acid), 14B (citric acid), and 14C (malic acid) for Example 10, respectively, and demonstrate experimental results supporting the ability of carboxylic acids having at least two carboxyl groups to promote the formation of primary ettringite and enhance the short-term mechanical strength of the aggregates obtained using the compositions of the present invention.

[0053] Summary of the Invention The present invention relates to a composition that can be used as a binder or cement additive for premixed cement products. The composition comprises ladle slag, calcium sulfate, at least one soluble sulfate (preferably selected from alkali sulfates and alkaline earth sulfates (excluding radioactive alkali or alkaline earth sulfates), and aluminum sulfate) having a solubility in water at 20°C in the range of 5 g / 100 mL to 90 g / 100 mL, and at least one carboxylic acid having at least two carboxyl groups, wherein the weight percentage of the at least one soluble sulfate is 0.3 to 10% of the total weight of the composition, the percentage ratio of calcium sulfate to ladle slag is 1:2 to 1:6, preferably 1:3 to 1:4, and the carboxylic acid is present in an amount of 0.05% to 3% by weight, preferably 0.17% to 1.5% of the total weight of the composition.

[0054] The present invention relates to using the composition of the present invention as a binder and / or cement additive for premixed cement products.

[0055] The cement containing the aforementioned additive can be used in premixed cement products.

[0056] The present invention also relates to a premixed cement product comprising the composition, aggregate and water, or a pre-hydrated premixed cement product comprising the composition and aggregate. The object of the present invention also relates to a hardened cement product obtained from the premixed cement product of the present invention.

[0057] Furthermore, the present invention relates to cement comprising the composition of the present invention. Detailed description of the present invention

[0058] The present invention relates to a composition comprising ladle slag, calcium sulfate, at least one soluble sulfate (preferably selected from alkali sulfates and alkaline earth sulfates (excluding radioactive alkali or alkaline earth sulfates), and aluminum sulfate) having a solubility in water at 20°C in the range of 5 g / 100 ml to 90 g / 100 ml, wherein the weight percentage of the at least one soluble sulfate is 0.3 to 10% of the total weight of the composition, the weight percentage ratio of calcium sulfate to ladle slag is 1:2 to 1:6, preferably 1:3 to 1:4, and the carboxylic acid is present in an amount of 0.05% to 3% by weight, preferably 0.17% to 1.5% of the total weight of the composition.

[0059] The aforementioned composition acts as a rapidly expanding binder and is therefore used as a binder in premixed cement products. Furthermore, it is also used as a cement additive.

[0060] The composition of the present invention has the advantage of rapidly developing mechanical strength in premixed cement products and cement to which it is added after being mixed with water and hardened.

[0061] Preferably, the composition of the present invention contains ladle slag in an amount of 37% to 84.65% by weight of the total weight of the composition, and more preferably in an amount of 71% to 75% by weight.

[0062] In another preferred embodiment, the composition of the present invention contains calcium sulfate in an amount of 15% to 50% by weight, more preferably 22% to 24% by weight, based on the total weight of the composition.

[0063] The ratio of calcium sulfate to ladle slag in the composition of the present invention is in the range of 1:2 to 1:6, preferably in the range of 1:3 to 1:4. In this way, ettringite is suitably formed compared to other hydration products.

[0064] Furthermore, according to another preferred embodiment, the composition of the present invention contains, in an amount of 0.3 to 10%, more preferably 2.7 to 3.5%, of the total weight of the composition, at least one soluble sulfate, preferably selected from alkali sulfates and alkaline earth sulfates (excluding radioactive alkali or alkaline earth sulfates), and aluminum sulfate, having a solubility in water at 20°C in the range of 5 g / 100 mL to 90 g / 100 mL.

[0065] In a particularly preferred embodiment, the composition of the present invention contains at least one carboxylic acid having at least two carboxyl groups in an amount of 0.05% to 3%, preferably 0.17% to 1.5%, of the total weight of the composition.

[0066] In a more preferred embodiment, the composition of the present invention has the following weight % composition. - Ladle slag: 37-84.65%; - Calcium sulfate: 15-50%; - Soluble sulfate: 0.3-10%; - Carboxylic acid: 0.05~3%.

[0067] In a more preferred embodiment, the composition of the present invention has the following weight % composition: - Ladle slag: 71-75% - Calcium sulfate: 22-24% - Soluble sulfates: 2.7-3.5% - Carboxylic acid: 0.3~0.7%

[0068] Preferably, the calcium sulfate used in the composition of the present invention is selected from anhydrous gypsum, gypsum, and scalyola. More preferably, the calcium sulfate used is in the form of anhydrous gypsum.

[0069] In a preferred embodiment, at least one soluble sulfate having a solubility in water at 20°C in the range of 5 g / 100 ml to 90 g / 100 ml is selected from alkali sulfates and alkaline earth sulfates (excluding radioactive alkali or alkaline earth sulfates), and aluminum sulfate, preferably selected from potassium sulfate, sodium sulfate, lithium sulfate, magnesium sulfate, and aluminum sulfate, and more preferably potassium sulfate.

[0070] In a more preferred embodiment, the carboxylic acid (at least dicarboxylic acid) having at least two carboxyl groups used in the composition of the present invention has a hydroxyl group at the α-position relative to the carboxyl group (α-hydroxy acid (AHA)). In a more preferred embodiment, the acid of the present invention is selected from tartaric acid, malic acid, citric acid, lactic acid, succinic acid, oxalic acid and / or malonic acid. The most preferred acid is tartaric acid. Salts of the above carboxylic acids, such as sodium salts or potassium salts of the acid, can also be used.

[0071] Ladle slag is mainly composed of amorphous calcium aluminate and exhibits hydraulic activity, exhibiting a rapid and strong exothermic reaction upon contact with water. The reactivity of the slag also depends on its fineness (Blaine value), as shown in the experimental section. The higher the Blaine value, i.e., the larger the surface area, the higher the reactivity of the slag.

[0072] In a preferred embodiment, the ladle slag used in the present invention has a Blaine fineness of 2,000 to 11,000 cm². 2 / g, more preferably 3,000 to 6,000 cm 2 It is / g.

[0073] Calcium sulfate is added to suppress the high heat generation of ladle slag. Calcium sulfate helps to regulate setting, pot life, and curing time.

[0074] Calcium sulfate and calcium aluminate in ladle slag react in the presence of water to produce ettringite, an expansive mineral. When used in premixed cement products mixed with water, ettringite determines the anti-shrinkage / expansion function of the composition of the present invention. In fact, to avoid impairing the performance of the settling material, it is desirable to avoid shrinkage of the material during the hardening of the settling material.

[0075] Ettringite typically forms at two points in time: once at the start of mixing of the binder and water (primary ettringite), and again when the binder hardens (secondary ettringite). Because secondary ettringite has volume, it introduces tensile conditions within the structure, potentially leading to structural failure and reduced mechanical performance. Therefore, it is desirable to avoid the formation of secondary ettringite.

[0076] In the composition of the present invention, at least one soluble sulfate having a solubility in water measured at 20°C in the range of 5 g / 100 ml to 90 g / 100 ml is preferably selected from alkali sulfates and alkaline earth sulfates (excluding radioactive alkali or alkaline earth sulfates), and aluminum sulfate, more preferably selected from potassium sulfate, sodium sulfate, lithium sulfate, magnesium sulfate, and aluminum sulfate, and even more preferably potassium sulfate, to control the rate of ettringite formation both in the short and long term in order to prevent continuous reactions between calcium sulfate, preferably anhydrous gypsum, and ladle slag. In fact, because it is more water-soluble than calcium sulfate, the soluble sulfate supplies sulfate ions to the slag more quickly, increasing the initial reactivity and promoting the formation of ettringite. Thus, in the presence of water, calcium sulfate reacts with calcium aluminate present in the ladle slag at a predetermined timing to quantitatively form primary ettringite and suppress the formation of secondary ettringite.

[0077] In other words, soluble sulfates enable ettringite formation only if the elastic modulus of the bond structure is still low. Thus, even if expansion due to ettringite is present, no mechanical tension is introduced that would overcome the physical resistance of the structure under tensile stress.

[0078] In a preferred embodiment, when the composition of the present invention is mixed with water, the formation of ettringite in the premixed cement product or cement is mainly observed within 24 hours after the start of mixing. In a more preferred embodiment, the formation of ettringite is observed only within 6 hours after the start of mixing.

[0079] In the bonding compositions of the present invention, a carboxylic acid having at least two carboxyl groups performs the known function of delaying the setting time. This is usually accompanied by a delay in the development of short-term mechanical strength. However, surprisingly, in the compositions of the present invention, the increase in setting time is not accompanied by the short-term decrease in mechanical strength that usually occurs. In contrast, when the carboxylic acid is present in an amount of 0.05% to 3%, preferably 0.17% to 1.5%, of the total weight of the composition, the mechanical strength of the resulting cementitious set or cement containing the additive increases, as demonstrated in the experimental portion.

[0080] Furthermore, the presence of a carboxylic acid having at least two carboxyl groups in an amount of 0.05% to 3% by weight, preferably 0.17% to 1.5%, relative to the total weight of the composition according to the present invention has the advantage of accelerating the formation rate of primary ettringite, as demonstrated in the experimental portion.

[0081] The premixed cement-based product of the present invention comprises a composition according to the present invention and (inert) aggregate, wherein the aggregate is selected from the group consisting of stone, artificial aggregate, sand, endogenous rock, extrinsic rock, expansive clay, glass, or a combination thereof.

[0082] The present invention further relates to a premixed cement-based product comprising the composition of the present invention, (inert) aggregate selected from stone, artificial aggregate, sand, endogenous rock, extrinsic rock, expansive clay, glass, or a combination thereof, and water.

[0083] In a preferred embodiment, the aggregate is present in the premixed cement product in an amount of 40% to 85% w / w relative to the weight of the dry mixture.

[0084] A premixed cement product containing the composition and aggregate described in any of the above embodiments needs to be hydrated before use, as described above. In a preferred embodiment, the water to be hydrated in the premixed cement product is added in an amount of 12% to 50% w / w relative to the weight of the dry mixture.

[0085] The object of the present invention also relates to cement-based solids obtained after hardening from the premixed cement-based products of the present invention.

[0086] Finally, the present invention also relates to the use of the composition described in the claim as a binder for premixed cement products and / or as a cement additive.

[0087] According to a preferred embodiment, the composition described in the claim is added to cement corresponding to the definitions of CEM 1 to CEM V in the standard UNI EN 197-1 2001.

[0088] Accordingly, the present invention also relates to cement comprising the composition described in the claims, preferably a cement that falls under the definitions of CEM 1 to CEM V in standard UNI EN 197-1 2001 and comprises the composition described in the claims.

[0089] In a preferred embodiment, the composition according to the claim is present in cement, preferably cement corresponding to the definitions of CEM 1 to CEM V in the UNI EN 197-1 2001 standard, in an amount ranging from 5% to 50%, preferably ranging from 25% to 45%.

[0090] The cement containing the additive can be used in premixed cement products. Therefore, the present invention also relates to using cement containing the claimed composition as a component of premixed cement products.

[0091] The present invention will be described below with reference to experimental examples, but these examples are not intended to limit the scope of the invention. [Examples]

[0092] Materials and methods In the experiments described in the following examples, the proportion of the amorphous phase was 94.1%, and the ladle slag according to the present invention having the following compositional proportions was used. JPEG2026511646000003.jpg143117 Preparation of pure paste samples for XRD / TGA analysis

[0093] In this test, the test sample consists only of binder components that do not contain inert components, allowing the device to more accurately read the mineral phase in the sample.

[0094] All raw materials used are in solid and powder form. After weighing, they are mixed manually until a homogeneous powder system is obtained.

[0095] For each binding composition used in the laboratory, five 50g test samples were prepared. 300g of material was weighed out for each sample preparation.

[0096] The required water is added to the powder according to an approximate mixing ratio of 1 kg of water per 1 kg of binder, and the powder and water are mixed together using an electric mixer for about 2 minutes until uniform. Finally, the mixture is poured into a plastic container.

[0097] The test samples were cured in an artificial climate chamber at 60% humidity and 21°C. XRD mineral analysis was performed using corundum as a standard, and for some samples, thermogravimetric analysis was performed 6 hours, 24 hours, 7 days, and 28 days after mixing with water to quantify the crystalline and amorphous phases in the samples. Preparation of standard mortar samples for mechanical strength testing

[0098] In this particular case, the sample always consisted of 30% of the binding phase under test and 70% of an inert phase made of standard sand (https: / / www.normensand.de / en / products / cen-standard-sand-en-196-1 / ). Therefore, the proportion of the binding phase was recalculated while maintaining various ratios so that it would be 30% of the standard mortar mix.

[0099] All raw materials used are in solid and powder form. After weighing, they are mixed manually until a homogeneous powder system is obtained.

[0100] The actual production of the mixture is carried out using an automated mechanical mixer, which is fitted with a stainless steel rotor that utilizes planetary motion to optimize the mixing of the raw materials. Furthermore, it operates in predetermined cycles in accordance with the standards of EN 196-1, EN 196-3:2005, and EN 480-1. Water is added to the powder at an estimated mixing ratio (kg H2O / kg powder) or at a water-to-binder ratio (kg H2O / kg binder) in a stainless steel container designed for the mixer. This material ensures durability during the cycle of use and prevents the bottom of the tray from peeling and releasing impurities due to wear, thereby suppressing the contamination of the mixture with impurities.

[0101] The first cycle lasts 1 minute and 30 seconds, during which the rotor operates at two different speeds. The speed is set low for the first minute, and then doubled for the remaining 30 seconds. At the end of this phase, the mixer automatically stops, and the mixture undergoes a 1 minute and 30 second pause. Finally, it is restarted, and the rotor rotates at maximum speed for 60 seconds. At the end of the process, the mixture should have sufficient workability to be handled plastically. The equipment used in this experiment was an automatic Matest mixer.

[0102] After the mixture is prepared, it is filled into a suitable mold, and the material undergoes a hardening process, reaching an initial hardening stage and acquiring the characteristic shape of the mold itself. The shape and dimensions of the mold vary depending on the type of test (UNI EN 196-1:2005). The mold is configured to consist of three horizontally arranged chambers, allowing three test specimens to be prepared simultaneously. The material is steel, with a wall thickness of approximately 10 mm. The specimen used for the strength test is a cube with a side length of 40 mm.

[0103] After the sample is prepared, the humidity is monitored and the sample is placed in a humidity chamber where the humidity is kept constant at 90-98% and the temperature at 23°C. The sample is left in this chamber for 24 hours. After 24 hours, if the sample has hardened sufficiently, the mold is removed. Otherwise, it is kept in the mold for the entire period deemed necessary. In either case, after 24 hours, the sample is moved from the humidity chamber to a drying chamber, where the humidity is kept constant at 60% and the temperature at 21°C. The sample is placed in the drying chamber for the entire time required for curing, from the time of preparation until the time of testing. Since the properties of construction binders change significantly with hydration time, each composition is tested with different settling and curing times. Therefore, the curing period is determined according to when the test is to be conducted.

[0104] Evaluation of compressive strength The compressive strength test uses a Controls L-1301 two-chamber apparatus compliant with EN196-1 (meeting precision class 1 of EN12390-4). The frame consists of two columns with two test chambers mounted on a steel base. The piston and cylinder are single-acting assemblies with an electrical limit switch to restrict piston movement. The compression chambers can withstand a maximum load of 250 kN and have cells with strain gauges (load cells) inserted between the upper cross member and the upper plate. The plate hardness is HV 600. During testing, it is covered with a transparent safety guard. The specimen used for the strength test is a 40 mm cube, inserted into a specific test chamber made of steel plate at the bottom of the press, and equipped with a placement system that allows for proper positioning.

[0105] Before measurement, the geometric properties of the test specimen, the set test speed value, and the sensitivity are specified in a particular software application. In this test, the load is applied at a speed of 1200 N / s at all set measurement points. The test ends when the specimen's resistance to the press becomes nearly zero, at which point the specimen reaches its fracture point, and its maximum strength is recorded.

[0106] Stress σ at compressive failure [N / mm] 2 ] is calculated by the following formula.

number

[0107] Potassium sulfate's ability to regulate ettringite formation in agglomerates obtained using the composition of the present invention. Two types of conjugated compositions according to the present invention, differing only in the presence or absence of potassium sulfate, were prepared, and the ability of these compounds to control ettringite formation by promoting primary ettringite formation and inhibiting secondary ettringite formation was demonstrated.

[0108] For each of the two types of binding compositions, five 50g test samples were prepared, and 300g of material was weighed out to make the final product. Pure paste sample for XRD / TGA analysis: JPEG2026511646000005.jpg45146

[0109] After weighing, the two compositions were mixed to homogenize each powder.

[0110] Water was added to the sample and an electric mixer was used. Care was taken to mix the powder and water for at least 2 minutes.

[0111] The mixture was poured into small plastic containers. Finally, the samples were cured in an artificial climate chamber with 60% relative humidity and 21 degrees Celsius.

[0112] The first composition sample was obtained by mixing with water, with a water / composition ratio of 0.6.

[0113] The second composition was obtained by mixing with water, with a water / cement ratio of 0.5.

[0114] Water at 4°C was used to prepare the sample.

[0115] Using corundum as a standard sample, XRD mineral analysis was performed 6 hours, 24 hours, 48 ​​hours, 7 days, and 28 days after mixing with water to quantify the crystalline and amorphous components in the test samples. The percentage of amorphous components refers to all components in the test sample that do not have a crystalline microstructure, and does not necessarily refer to the initial amorphous calcium aluminate.

[0116] Ladle slag reagents contain periclase, dolomite, and quartz phases. Calcite, syngenite, monosulfate, and portlandite phases are formed after the hydration reactions of these compositions.

[0117] Referring to the row for ettringite in Table 1 of Figure 1, it can be seen that in the coagulation obtained from compositions without potassium sulfate, ettringite formation continues over time, but the majority of the growth is observed in the first few hours. On the other hand, in the coagulation obtained from compositions with added potassium sulfate, ettringite formation is observed to increase in the first 24 hours and then decrease thereafter.

[0118] Further supporting this analysis, as shown in Table 1 of Figure 1, the proportion of anhydrous gypsum, i.e., calcium sulfate used as the reagent for ettringite formation, appears to be changing. In the system without potassium sulfate, the proportion of anhydrous gypsum remains higher even after a long period compared to the system with added potassium sulfate. In fact, after 28 days, the proportion of anhydrous gypsum was 2.6% in the system without potassium sulfate, compared to 1.1% in the system with potassium sulfate. Therefore, the reactivity of the first system without potassium sulfate was lower at 28 days compared to the reactivity of the second system with less potassium sulfate, indicating insufficient control. [Example 2]

[0119] Analysis of compressive strength The addition of potassium sulfate leads to an increase in ettringite formation in the first few hours, as shown in Example 1 above. Furthermore, the addition of potassium sulfate leads to an increase in mechanical strength (CS) and a reduction in curing time.

[0120] The binding composition according to the present invention was prepared with 70% inert phase (standard sand) and 30% binding phase, and was configured as follows. JPEG2026511646000006.jpg27145 4°C water was used to prepare the test sample.

[0121] JPEG2026511646000007.jpg101142 [Example 3]

[0122] Comparative example of compressive strength (CS) of a composition containing BOF described in international application WO2022238376 and a composition containing ladle slag used in the present invention. The compressive strength (CS) of compositions containing BOF as described in international application WO2022238376, particularly Composition 1 on page 29, was compared with that of compositions containing ladle slag used in the present invention.

[0123] As can be seen from Table 3 below, using ladle slag instead of BOF yields greater mechanical strength in the same amount of time.

[0124] In particular, this occurs when the mixing ratio of ladle slag is higher compared to BOF. As is known from specialized literature, mechanical strength usually decreases as the mixing ratio increases, but this phenomenon does not occur when ladle slag is used.

[0125] JPEG2026511646000008.jpg71148

[0126] In the ladle slag-based composition, the binder is set to 100%, but this needs to be recalculated to 30% and entered into the standard mortar for CS calculations.

[0127] Water at 4°C was used to collect the test samples.

[0128] The composition containing ladle slag used in this invention exhibits improved mechanical strength compared to the composition using BOF according to WO2022238376, even in the presence of calcium sulfate, as shown in Table 4 below. In this case as well, a higher mixing ratio was used in the composition containing ladle slag used in this invention, and a higher CS value was achieved, contrary to the values ​​expected from specialized literature.

[0129] JPEG2026511646000009.jpg99147

[0130] In the ladle slag-based composition, the binder is set to 100%, but this is recalculated to 30%, and the CS is calculated by inputting this into the standard mortar formula.

[0131] Water at 4°C was used to collect the test samples. [Example 4]

[0132] A comparative example of a composition containing BOF or GGBS as described in application WO2022238376 and a CS of the composition according to the present invention. Table 5 shows the change in compressive strength (CS) of the composition according to the present invention over time. Table 5 JPEG2026511646000010.jpg137148

[0133] In the ladle slag-based composition, the binder is assumed to be 100%, but this needs to be recalculated to 30% and entered into the standard mortar for CS calculations.

[0134] As can be seen in Examples 2-51, 53-66, and 68-75 of application WO2022238376, none of the inventive compositions described therein have achieved the mechanical strength, even after 28 days. [Example 5]

[0135] Demonstration of the ability of tartaric acid to improve the short-term mechanical strength of agglomerates obtained using the composition of the present invention. The binding composition of the present invention was prepared using 70% inert phase (standard sand) and 30% binding phase. The composition is as follows: JPEG2026511646000011.jpg70133

[0136] Water at 4°C was used to prepare the test sample for composition 4, while water at room temperature was used for the other test samples.

[0137] The test samples were prepared by adding water and using an automatic mixer. The mixture was poured into a 4 x 4 x 4 cm cube and compressed. Finally, the test samples were cured for 24 hours, 7 days, and 28 days according to the UNI EN 12190 standard (PCC conditioning). It was demonstrated that increasing the proportion of tartaric acid in the composition resulted in a longer setting time with increasing proportion, while also increasing the mechanical compressive strength after 24 hours. This is not observed in conventional systems. Normally, an increase in setting time leads to a decrease in mechanical performance.

[0138] Table 6 JPEG2026511646000012.jpg93169(*) Unlike the other samples, this one uses cold water and therefore cannot be compared.

[0139] Table 7 JPEG2026511646000013.jpg135129 [Example 6]

[0140] Demonstration of tartaric acid's ability to promote primary ettringite formation. Two conjugated compositions according to the present invention, differing only in the presence or absence of tartaric acid, were prepared, and the ability of these compounds to promote primary ettringite formation was demonstrated.

[0141] To prepare five 50g test samples, 300g of material was weighed for each of the two compositions.

[0142] Pure paste sample for XRD analysis without inert phase: JPEG2026511646000014.jpg72134

[0143] After weighing, the two compositions were mixed separately to homogenize the powders.

[0144] To prepare the test sample, water was added and the powder and water were carefully mixed for at least 2 minutes using an electric mixer.

[0145] The mixture was then poured into small plastic containers. Finally, the test samples were cured in an artificial climate chamber with 60% humidity and a temperature of 21°C.

[0146] Water at 4°C was used to obtain the test sample for composition 4, and water at room temperature was used to obtain the test sample for composition 7.

[0147] The initial composition, ladle slag (simply labeled "slag" in Table 8 of Figure 2), was made by mixing anhydrous gypsum and potassium sulfate, after which water was added.

[0148] In the second composition, ladle slag (simply referred to as "slag" in Table 8 of Figure 2) was mixed with anhydrous gypsum, potassium sulfate, and tartaric acid (simply referred to as "acid" in Table 8 of Figure 2) in an amount of 0.5% by weight of the total composition, and then water was added.

[0149] The presence of tartaric acid in the binding composition of the present invention accelerates the formation of primary ettringite. In fact, as shown in Table 8 of Figure 2, after 6 hours, it is observed that the consumption rate of ladle slag and anhydrous gypsum to form the product ettringite is higher when tartaric acid is present compared to when tartaric acid is not present. As a result, when tartaric acid is present in the binding composition, the proportion of primary ettringite formed by the reaction between the calcium aluminate of the ladle slag and anhydrous gypsum is greater. [Example 7]

[0150] Demonstration of the curing-accelerating effect of carboxylic acids in the composition according to the present invention. . When the curing time is the same, using a carboxylic acid having at least two carboxyl groups in compositions F1, F2, F3, F4, and F5 according to the present invention improves the mechanical strength and hydration of the bond structure. Furthermore, it has also been shown to have an effect as a setting accelerator.

[0151] Table 9 below clearly shows the increase in setting time and compressive strength.

[0152] The binding composition according to the present invention was prepared with a composition of 70% inert phase (standard sand) and 30% binding phase (Table 9). JPEG2026511646000015.jpg111142 JPEG2026511646000016.jpg180141 (*) Unlike the other samples, cold water was used, so a comparison is not possible.

[0153] Water at 4°C was used to obtain the test sample for formulation 4, while room temperature water was used for the other samples. [Example 8]

[0154] Comparative example: A composition in which the weight percentage content of carboxylic acid exceeds the range of carboxylic acid content present in the composition of the present invention. The binding composition of the present invention was prepared with 70% inert phase (standard sand) and 30% binding phase, and had the following composition. JPEG2026511646000017.jpg203127

[0155] For the preparation of the test samples, room temperature water was added and an automatic mixer was used. The mixture was poured into 4 x 4 x 4 cm cube molds and compression molded. Finally, the test samples were cured for 24 hours, 7 days, and 28 days according to the UNI EN 12190 standard (PCC conditioning).

[0156] Table 10 below compares the test results described above with the experimental results conducted in Example 5. JPEG2026511646000018.jpg70147

[0157] Based on the intensity measured at concentrations higher than those of the composition of the present invention, tartaric acid is a retarder for both setting and curing. This is as known from the literature. [Example 9]

[0158] Controllability of soluble sulfates for ettringite formation in aggregates obtained using the composition of the present invention. To demonstrate the ability of soluble sulfates to control ettringite formation, promote primary ettringite formation, and inhibit secondary ettringite formation, five conjugated compositions according to the present invention were prepared. Each composition contained ladle slag, anhydrous gypsum, and a soluble sulfate in equal proportions, but differed in the type of soluble sulfate used, which was potassium sulfate, lithium sulfate, sodium sulfate, magnesium sulfate, or aluminum sulfate (Table 11).

[0159] The five compositions were compared to similar bonding compositions that did not contain soluble sulfates. In all compositions, the same batch was used for the base ingredients, ladle slag, and anhydrous gypsum.

[0160] A pure paste sample was prepared for XRD analysis by removing the inert phase. JPEG2026511646000019.jpg118127

[0161] For each binding composition, five 50g test samples were prepared. 300g of material was weighed for sample preparation. After weighing, each composition was mixed to ensure uniformity of the powder. When preparing the test samples, care was taken to ensure that the powder and water were uniformly mixed using an electric mixer.

[0162] The mixture was poured into small plastic containers. Finally, the test samples were cured in an artificial climate chamber with 60% humidity and a temperature of 21°C.

[0163] Water at 4°C was used to collect the test samples.

[0164] To quantify the crystalline and amorphous phases in the test samples, XRD mineral analysis was performed using corundum as a standard, 6 hours, 24 hours, 7 days, and 28 days after mixing with water.

[0165] As can be seen from the results in Tables 12A (potassium sulfate), 12B (sodium sulfate), 12C (lithium sulfate), 12D (magnesium sulfate), and 12E (aluminum sulfate), respectively, shown in Figures 3, 4, 5, 6, and 7, soluble sulfates control ettringite formation, increasing it mainly within the first few hours after the start of the reaction. During this time, the plastic phase of the test sample allows ettringite formation without stressing the mineral. Subsequently, the proportion of ettringite remains almost constant or decreases. In this way, the formation of secondary ettringite is suppressed in the long term. [Example 10]

[0166] Demonstration of the ability of a carboxylic acid having at least two carboxyl groups to delay the setting time and improve the short-term mechanical strength of a coagulation obtained using the composition of the present invention. A carboxylic acid having at least two carboxyl groups delays the setting time of the coagulation obtained using the composition of the present invention and improves its short-term mechanical strength. To demonstrate the capabilities, three types of binding compositions according to the present invention were prepared. Each composition contained ladle slag, anhydrous gypsum, and potassium sulfate in equal proportions, and the carboxylic acids used (tartaric acid, citric acid, and malic acid) differed from one another (Table 13).

[0167] A pure paste sample was prepared for XRD analysis, and the binding composition according to the present invention was prepared with a composition of 70% inert phase (standard sand) and 30% binding phase, and was prepared as follows for mechanical strength. JPEG2026511646000020.jpg94153

[0168] For each binding composition, five 50g test samples were prepared. These samples were prepared by weighing 300g of material.

[0169] After weighing, each composition was mixed to ensure uniformity of the powder. For the preparation of the test samples, care was taken to ensure uniform mixing of the powder and water using an electric mixer.

[0170] The mixture was poured into small plastic containers. Finally, the test samples were cured in an artificial climate chamber with 60% humidity and a temperature of 21°C.

[0171] For the preparation of the test samples, water at 4°C was used for formulation 4, and water at room temperature was used for the formulation with added acid.

[0172] XRD mineralogical analysis was performed using corundum as a standard, and thermogravimetric analysis (TGA) was performed at 6 hours, 24 hours, 7 days, and 28 days after mixing with water to quantify the crystalline and amorphous phases and degree of hydration of the test samples.

[0173] As can be seen from the results in Tables 14A (tartaric acid), 14B (citric acid), and 14C (malic acid) shown in Figures 8, 9, and 10, respectively, carboxylic acids having at least two carboxyl groups delay the curing time of the system and, at the same time, improve the mechanical performance of the system, especially in the short term. Carboxylic acids having at least two carboxyl groups act as both a setting retarder and a curing enhancer.

[0174] To analyze this enhancing effect of carboxylic acids containing at least two carboxyl groups, thermogravimetric analysis was also performed to support the mineralogical analysis. This allows for a better assessment of the contribution of carboxylic acid addition to the reactivity of the test samples. In fact, hydration of the system occurs not only from the formation of crystalline minerals but also from hydrated amorphous or nearly crystalline structures that are not detected by XRD. To determine the w / w% (weight percent) of hydrated test samples, TGA analysis was performed to measure the weight loss of water with increasing temperature.

[0175] The temperature range known to be the loss range for reaction products (amorphous and crystalline) is as follows: - Weight loss (% w / w) at 25~200°C: All sulfate and aluminate hydrate systems - Weight loss (% w / w) at 200~550℃: Portlandite and amorphous gels (both aluminate and silicate).

[0176] Analysis of the obtained data reveals that the addition of tartaric acid is preferable, although similar effects, albeit less intense, are observed with the addition of malic acid or citric acid. In the short term, specifically after 6 and 24 hours, all test samples containing carboxylic acid showed a greater proportion of hydrated products and greater weight loss due to hydration compared to the system without the analyte.

[0177] The trend becomes more variable from day 7 onwards, but this is not particularly important from a functional standpoint, as a dense and compact structure is formed within a few hours of the start of hydration.

[0178] To evaluate the mechanical strength data after 24 hours for reference examples and tests with the addition of 0.15% of various carboxylic acids, a composition of the present invention consisting of 70% inert phase (standard sand) and 30% binder phase was prepared. In the reference example composition, the binder phase consisted of 21.8% ladle slag, 7.2% anhydrous gypsum, and 1% K2SO4, whereas the binder phase of the analyzed test samples consisted of 21.64% ladle slag, 7.21% anhydrous gypsum, 1% K2SO4, and 0.15% carboxylic acid.

[0179] For the preparation of the test samples, cold water at 4°C was added and an automatic mixer was used.

[0180] In all formulations, the water ratio to the total amount of ingredients (inert substance + binder) was 13%. The mixture was poured into a 4 x 4 x 4 cm cube and compressed. Finally, the test samples were cured for 24 hours according to UNI EN 12190 standard (PCC tempering).

[0181] The results are shown in Table 15 below. Table 15 JPEG2026511646000021.jpg28147 [Example 11]

[0182] Examples of cement containing the composition of the present invention The mechanical strength (CS) after 24 hours was evaluated for CEM I 52.5 R cement to which the following compound of the present invention was added. JPEG2026511646000022.jpg35136JPEG2026511646000023.jpg50136

[0183] The presence of the composition according to the present invention improves the compressive strength CS of CEM I 52.5 R cement after 24 hours.

Claims

1. A composition comprising ladle slag, calcium sulfate, at least one soluble sulfate having a solubility in water at 20°C of 5 g / 100 mL to 90 g / 100 mL, and at least one carboxylic acid having at least two carboxyl groups, wherein the weight percentage of the at least one soluble sulfate is 0.3 to 10% of the total weight of the composition, the percentage ratio of calcium sulfate to ladle slag is 1:2 to 1:6, preferably 1:3 to 1:4, and the carboxylic acid is present in an amount of 0.05 to 3% by weight, preferably 0.17 to 1.5%, of the total weight of the composition.

2. The composition according to claim 1, wherein the ladle slag has a blain fineness of 2,000 to 11,000 cm². 2 / g, more preferably 3,000 to 6,000 cm 2 A composition that is / g.

3. A composition according to any one of claims 1 to 2, wherein the weight percentage of ladle slag is 37% to 84.65%, preferably 71% to 75%, of the total weight of the composition.

4. A composition according to any one of claims 1 to 3, wherein the weight percentage of calcium sulfate is 15% to 50%, preferably 22% to 24%, based on the total weight of the composition.

5. A composition according to any one of the above claims, wherein the weight percentage of the at least one soluble sulfate is 2.7 to 3.5% of the total weight of the composition.

6. A composition according to any one of claims 1 to 5, wherein the calcium sulfate is selected from anhydrous calcium sulfate, calcium sulfate dihydrate, and calcium sulfate hemihydrate, and preferably anhydrous calcium sulfate.

7. A composition according to any one of the above claims, wherein the at least one soluble sulfate is selected from alkali sulfates, alkaline earth sulfates, and aluminum sulfate (excluding radioactive alkali or alkaline earth sulfates), preferably selected from potassium sulfate, sodium sulfate, lithium sulfate, magnesium sulfate, and aluminum sulfate, and more preferably potassium sulfate.

8. The composition according to any one of claims 1 to 7, wherein the at least one dicarboxylic acid has a hydroxyl group at the α-position relative to the carboxyl group, and more preferably the carboxylic acid is selected from tartaric acid, malic acid, citric acid, lactic acid, succinic acid, oxalic acid and / or malonic acid.

9. Use of the composition according to any one of claims 1 to 8 as a binder and / or cement additive for premixed cement products.

10. A premixed cement product comprising a composition and aggregate according to any one of claims 1 to 8, wherein the aggregate is selected from the group consisting of stone, artificial aggregate, sand, endogenous rock, extrinsic rock, expansive clay, glass, or a combination thereof, and is a premixed cement product in a hydrated dry form.

11. A premixed cement product obtained by mixing a composition according to any one of claims 1 to 8 with water and aggregate, wherein the aggregate is selected from the group consisting of stone, artificial aggregate, sand, endogenous rock, extrinsic rock, expansive clay, glass, or a combination thereof.

12. A cement-based solid made using the premixed cement-based product described in any one of claims 10 to 11.

13. A cement comprising the composition described in any one of claims 1 to 8, preferably a cement that corresponds to the definitions of CEM 1 to CEM V in the UNI EN 197-1 2001 standard.

14. The cement according to claim 13, wherein the composition is present in an amount of 5% to 50%, preferably 25% to 45%.

15. Use of the cement described in any one of claims 13 to 14 as an ingredient in a premixed cement product.

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