Method of producing cementious material from electric arc furnace slag

Abstract

A binder material is produced by a process including an Electric Arc Furnace (EAF) slag, chemically modifying the EAF slag to achieve a target chemistry suitable for binder applications, quenching the chemically modified EAF slag by slow cooling to promote the formation of a mineralized and crystallized structure, and grinding the slow-cooled slag to form a powdered binder material.

Description

METHOD OF PRODUCING CEMENTIOUS MATERIAL FROM ELECTRIC ARCFURNACE SLAGCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This patent claims priority to U.S. Provisional Application 63 / 656,639, filed on June 6, 2024. The disclosure of this prior application is considered part of the disclosure of this application and is hereby incorporated by reference in its entirety.FIELD

[0002] The present disclosure relates generally to a method of producing a cementitious material from electric arc furnace slag.BACKGROUND

[0003] This section provides background information related to the present disclosure and is not necessarily prior art.

[0004] The steelmaking industry generates significant volumes of byproducts, including various types of slags. Electric Arc Furnace (EAF) slag, in particular, is a voluminous byproduct of EAF steelmaking. There exists a continued need in the art for sustainable utilization of materials waste streams associated with steelmaking, and specifically, a need to utilize slag materials that are generated as a byproduct during this process. Traditionally, the disposition of EAF slag has posed environmental and logistical challenges, often resulting in landfilling, which is economically and environmentally undesirable.

[0005] The construction industry, concurrently, faces its own sustainability challenges. Ordinary Portland Cement (OPC) is a primary binder in concrete, but its production is energy- intensive and a significant source of anthropogenic carbon dioxide (CO2) emissions due to the calcination of limestone and high-temperature kiln operations. Consequently, there is a strong demand for supplementary cementitious products (SCPs) that can replace a portion of OPC in concrete, thereby reducing the environmental footprint of construction, and for alternative binder systems that may offer lower embodied energy and CO2 emissions.

[0006] While EAF slag possesses some inherent cementitious properties, its direct use in high- value cementitious applications is often limited by its chemical and mineralogical variability, andpotentially undesirable physical characteristics. The composition of EAF slag can fluctuate based on the specifics of the steelmaking process, the scrap input, and furnace operations. This variability can affect its performance and predictability as a cementitious material. Furthermore, unmodified EAF slag may present difficulties in processing, such as high grinding energy requirements, or may not achieve optimal reactivity for cementitious applications or CO2 absorption.

[0007] Prior methods of modifying slag, such as simply blending it or attempting bulk additions of chemical modifiers, may not always result in a homogenous, effectively modified product with consistent properties. There is a need for more controlled and efficient processes to chemically tailor EAF slag to achieve specific target chemistries and physical structures that optimize its performance for different end-uses, such as a replacement for Granulated Blast Furnace Slag (GBFS) or as a binder material suitable for CO2 curing.

[0008] Moreover, there is a growing global interest in technologies that can capture, utilize, or sequester CO2. Developing construction materials from industrial byproducts that can also serve as a sink for CO2, through mineralization or enhanced absorption, aligns with circular economy principles and climate change mitigation efforts.

[0009] Therefore, there remains a need for improved and efficient methods to transform EAF slag from a waste stream into consistently high-performing, value-added cementitious products. Such methods should address the chemical and physical modification of the slag, including controlled quenching and grinding, to produce materials suitable for specific construction applications, including those that can contribute to sustainable construction practices and potentially offer enhanced CO2 interaction.SUMMARY

[0010] An aspect of the disclosure provides a binder material produced by a process comprising: receiving an Electric Arc Furnace (EAF) slag; chemically modifying the EAF slag to achieve a target chemistry suitable for binder applications; quenching the chemically modified EAF slag by slow cooling to promote the formation of a mineralized and crystallized structure; and grinding the slow-cooled slag to form a powdered binder material.

[0011] Aspects of the disclosure may include one or more of the following optional features. The chemical modification of the EAF slag may further include determining slag suitability by comparing historical slag chemistry data to the target chemistry using a compositional diagram,and determining the ease and cost of modifying the slag chemistry using a mass balance and economic model. The chemical modification of the EAF slag may further include determining a combination of reagents to add to the EAF slag, the reagents selected from the group consisting of Aluminum, Ladle Metallurgical Furnace (LMF) slag, silica sand, glass, lime, calcium carbide, biochar, fly-ash, bottom ash, and combinations thereof.

[0012] The chemical modification of the EAF slag may also involve metering a base dose of selected reagents into a slag transporting vessel contemporaneously as liquid slag is received, at a prescribed rate of approximately 1 to 5 tons per minute; performing a rapid slag analysis of the slag during or after the base dose addition using laser spectrometry or other quick method, and performing a final reagent dosing based on the rapid slag analysis to achieve the target chemistry. Following the final reagent dosing, the process may further include agitating the slag in the slag transport vessel using a mechanical mixer designed for high temperatures or by pneumatic stirring with compressed oxygen blown into the liquid slag with a lance.

[0013] The quenching of the chemically modified EAF slag by slow cooling may include pouring the molten slag into an open pit and allowing it to cool under ambient conditions, optionally with a water spray applied after pouring to control dust or manage the cooling rate. After pouring the molten slag into an open pit and before grinding, the process may further comprise performing coarse metal recovery by magnetic separation to remove metallic particles larger than approximately two inches. Also after pit cooling and before grinding, the process may involve crushing the pit-cooled slag to a size less than approximately one inch, followed by a further magnetic separation to remove metallic pieces larger than approximately a half inch. Grinding the slow-cooled slag may comprise grinding to a fineness where at least 90% of the powdered binder material passes through a 45-micron sieve. The process may further include performing magnetic separation during the grinding to remove metallic pieces larger than approximately 0.05 inches.

[0014] Another aspect of the disclosure provides a supplemental cementitious product produced by a process comprising: (a) receiving an Electric Arc Furnace (EAF) slag; (b) chemically modifying said EAF slag to achieve a target chemistry suitable for supplemental cementitious product applications, enhancing its suitability for use in Portland cement systems; (c) quenching the chemically modified EAF slag by rapid granulation to promote the formation of apredominantly amorphous, glassy structure; and (d) grinding the granulated slag to form a fine powdered supplemental cementitious product.

[0015] Aspects of the disclosure may include one or more of the following optional features. The chemical modification of the EAF slag may further comprise determining slag suitability for supplemental cementitious product applications by comparing slag chemistry data to said target chemistry, wherein said target chemistry is optionally equivalent to that of Granulated Blast Furnace Slag (GBFS), using a compositional diagram, and utilizing a mass balance and economic model to determine the feasibility of said chemical modification.

[0016] The chemical modification of the EAF slag may further include determining a combination of reagents to add to said EAF slag, said reagents selected from the group consisting of Aluminum, Ladle Metallurgical Furnace (LMF) slag, silica sand, glass, lime, calcium carbide, bio-char, fly-ash, bottom ash, and combinations thereof, to achieve said target chemistry. The chemical modification may also involve metering a base dose of selected reagents into a slag transporting vessel contemporaneously as liquid slag is received, performing a rapid slag analysis of the slag during or after said base dose addition, and performing a final reagent dosing based on said rapid slag analysis to achieve said target chemistry, optionally with agitation of the molten slag to ensure mixing.

[0017] The quenching by rapid granulation may include air granulation, wherein the molten slag is directed over a stream of air having a pressure of approximately 20 to 60 psi and an air flow rate of approximately 10,000 to 20,000 cubic feet per minute (cfm) per ton per minute of slag flow rate. Alternatively, the quenching by rapid granulation may include water granulation, wherein the molten slag is directed into a stream of water having a pressure of approximately 20 to 40 psi and a water flow rate of approximately 1,200 to 2,400 gallons per minute (gpm) per ton per minute of slag flow rate.

[0018] Grinding the granulated slag may include grinding to a fineness where at least 90% of the powdered supplemental cementitious product passes through a 45-micron sieve, and optionally performing magnetic separation during said grinding to remove metallic pieces. The predominantly amorphous, glassy structure formed by said rapid granulation may impart enhanced hydraulic and / or pozzolanic reactivity to the powdered supplemental cementitious product when used in Portland cement systems. The powdered supplemental cementitious product may be suitable for replacing approximately 0 to 50%> by weight of Portland cement in concreteformulations. This replacement of Portland cement with said powdered supplemental cementitious product in concrete formulations may contribute to one or more of: enhanced compressive strength of the resulting concrete, improved durability of the resulting concrete, and a reduction in the overall carbon footprint of the concrete.DRAWINGS

[0019] The drawings described herein are for illustrative purposes only of selected configurations and not all possible implementations, and are not intended to limit the scope of the present disclosure.

[0020] FIG. 1 is a flow chart illustrating an example set of steps for producing a cementitious material from electric arc furnace slag according to the present disclosure.

[0021] Corresponding reference numerals indicate corresponding parts throughout the drawings.DETAILED DESCRIPTION

[0022] Example configurations will now be described more fully with reference to the accompanying drawings. Example configurations are provided so that this disclosure will be thorough, and will fully convey the scope of the disclosure to those of ordinary skill in the art. Specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of configurations of the present disclosure. It will be apparent to those of ordinary skill in the art that specific details need not be employed, that example configurations may be embodied in many different forms, and that the specific details and the example configurations should not be construed to limit the scope of the disclosure.

[0023] Referring to FIG. 1, a first aspect of the disclosure relates to a method 100 for forming an ordinary Portland cement (OPC) replacement product using a chemically-modified electric arc furnace (EAF) slag. At a first step 102a, EAF slag is initially received from an EAF furnace in a molten or liquid state. The existing slag chemistry for each type of slag is typically known, and target chemistries are often visualized using compositional diagrams (e.g., ternary diagrams) to guide the modification process. In some examples, the EAF slag is provided in a bulk state within a slag pot.

[0024] Next, at step 104, a comprehensive slag suitability determination is performed prior to the chemical modification of the EAF slag. This determination begins with an analysis where a ternary plot, or similar compositional diagram, is used to compare historical and current EAF slag chemistry data against target chemistries optimized for specific end uses, such as supplementary cementitious material (SCM) applications or mineralized binder applications. Concurrently, a mass balance and economic model is employed to assess the end-use feasibility, considering the ease and cost associated with modifying the existing slag chemistry to achieve the desired target chemistry. Based on this analysis, an optimal recipe 105 of reagents needed to modify the slag chemistry is determined. The selection of reagents is critical and may include, but is not limited to materials such as Aluminum (e.g., recycled cans, turnings, ingots), ladle metallurgical furnace (LMF) slag from steelmaking operations, silica sand, glass (e.g., cullet, glass fibers), Lime, Calcium Carbide, bio-char, fly-ash, and / or bottom ash.

[0025] Following the determination of the reagent recipe 105 as per step 104, the process moves to the controlled addition of the reagents (i.e., slag modifiers) to the molten EAF slag at step 108, whereby the EAF slag is chemically modified by adding one or more slag modifiers to adjust a lime to silica ratio (hereafter referred to as the C / S ratio). The base dose of the selected reagents 106 is metered into the slag transporting vessel contemporaneously as the liquid slag 101 is being received into the vessel. This simultaneous addition ensures early interaction between the slag 101 and the reagents 106. The reagents 106 are introduced at a prescribed rate, typically determined by the mass balance and economic model in step 104, ranging from approximately 1 ton per minute to 5 tons per minute. This metered addition is accomplished using a combination of mechanical and pneumatic transport systems designed to handle the specific reagents and deliver them accurately into the vessel containing the molten slag. This method contrasts with previous, less effective bulk addition techniques and promotes a more homogenous mixture and efficient chemical reaction.

[0026] In one example of the method 100a, the step 108 of modifying the EAF slag includes adding a slag modifier 106 including a ladle metallurgical furnace (LMF) slag to the EAF slag to reduce the C / S ratio. Generally, reducing the C / S ratio of the modified EAF slag results in an improvement to the finished cementious material including the modified EAF slag, whereby the reduced C / S ratio facilitates increased strength and reduced cure times. In another example, the step 108 of modifying the EAF slag includes adding a slag modifier 106 including a combinationof the LMF slag and at least one of flyash and / or soda glass, which further reduces the C / S ratio of the modified EAF slag 109b. In yet another example, the step of modifying the EAF slag includes adding a slag modifier 106 comprising a composition including the LMF slag, at least one of the flyash or soda glass, and an aluminum. Including the aluminum in the slag modifier 106 further reduces the overall iron and manganese content of the modified EAF slag 109b below 10% by weight, and more preferably, below 5% by weight of the modified EAF slag 109b.

[0027] To further refine the chemical modification step 108 and ensure the precise target slag chemistry is achieved, the composition of the slag 101 and reagents 106 may be continuously or iteratively analyzed during the reagent dosing phase at step 110. This analysis step 110 involves employing rapid slag analysis techniques, such as laser spectrometry or other suitable quick methods, which can provide near real-time feedback on the evolving slag chemistry. The results 109 from this rapid analysis can be immediately fed back into a controller for the dosing system at step 104, allowing for dynamic adjustments to the reagent recipe 105. This iterative loop of analysis and adjusted dosing helps to meticulously steer the slag towards its final target composition, compensating for any variations in the initial slag or the reagent interactions.

[0028] Following the initial dosing 108 and any near real-time analysis 110, a final reagent dosing step 112 ensures the slag chemistry precisely meets the target slag chemistryl05. First, the results from the rapid slag analysis are inputted into the Mass Balance & Economic Model. This allows for an updated assessment of the current slag composition. Next, the actual, now-measured slag chemistry 111 is formally compared against the predetermined target slag chemistry 105. Based on this comparison, any remaining deficiencies or necessary adjustments are identified, and a final reagent dosing is completed to achieve the precise target chemistry. To ensure thorough homogenization of these final additions of reagents 106 with the bulk of the molten slag 101, agitation within the slag transport vessel may be implemented. This agitation can be performed using a mechanical mixer specifically designed for operation at extremely high temperatures, or alternatively, through pneumatic stirring, for instance, by blowing compressed oxygen into the liquid slag with a lance to promote complete mixing of the reagents 106.

[0029] After the EAF slag 101 is mixed with the slag modifier 106 and the target slag chemistry 105 is achieved, the modified EAF slag 113 is processed at a quenching step 114, whereby the modified EAF slag 113 is cooled at a controlled rate to change a state of the modified EAF slag 113 from a liquid state to a solid state to form a solidified modified EAF slag 113.Different cooling processes may be utilized depending on the desired end use of the modified EAF slag 113

[0030] The slow cooling process, designed to promote mineral and crystal formation, begins by pouring the molten slag into an open pit. Here, it's allowed to cool gradually under ambient conditions. Optionally, water may be sprayed onto the slag after it has been poured into the pit, primarily to control dust or manage the cooling rate without inducing rapid quenching. As the modified slag 113 is cooled, the modified slag 113 undergoes a coarse metal recovery step 116, where magnetic separation is employed to remove large metallic particles, typically those greater than two inches (2”) in size. Following this, the material is subjected to a crushing step. The pit- cooled slag 117a is first crushed to a size of less than one inch (1”) to form a crushed slag 119a. After this initial crushing, a further magnetic separation step is used to remove smaller metallic pieces, those greater than a half inch (1 / 2”), from the crushed slag 119a. This method of slow cooling results in a non-granulated material.

[0031] For the air granulation process 114b, the modified molten slag is poured into a tundish or onto a runner, which then directs the slag flow over a high-velocity stream of air. This air stream typically has a pressure ranging from 20 to 60 psi. The corresponding air flow rate is generally maintained between 10,000 to 20,000 cubic feet per minute (cfm) per ton per minute of the slag flow rate. This rapid exposure to the air stream quickly quenches the slag, solidifying it into small, typically amorphous or glassy, granules. This method is designed to prevent significant mineral or crystal formation.

[0032] In the water granulation process 114c, the modified molten slag 113 is directed, typically via a tundish or runner, into a high-pressure stream of water. The water is generally supplied at a pressure ranging from 20 to 40 psi, with a flow rate of approximately 1,200 to 2,400 gallons per minute (gpm) per ton per minute of slag flow. This immediate and intense contact with the water causes the molten slag to rapidly quench and disintegrate into small, glassy granules. Similar to air granulation, this rapid cooling inhibits the formation of significant crystalline mineral structures, favoring an amorphous state in the resulting granulated material.

[0033] Regardless of whether the modified slag 113 has been subjected to slow cooling 114a and crushing 120a to form the crushed slag 121a or rapidly quenched via air granulation 114b or water granulation 114c to form a granulated slag 121b, 121c, the subsequent step 122 involves grinding the material into a fine powder. This grinding process 122 is typically performed toachieve a specific particle size distribution, often aiming for a fineness where approximately 90% of the powdered material passes through a 45-micron sieve, or even finer depending on the intended application. During the grinding process 122, magnetic separation techniques may also be employed to remove any fine metallic pieces, for instance, those larger than 0.05 inches, that may have been liberated or remain in the material. This ensures the purity and quality of the final powdered slag 124 product.

[0034] The ground material 123a derived from the slow-cooled modified EAF slag 121a is particularly well-suited to function as a primary binder. This powdered slag 123a can be used directly, without the addition of any Portland cement, to bind coarse and fine aggregates, which can then be formed into various construction products such as pavers or concrete blocks.

[0035] The granulated forms 123b, 123 c of the modified EAF slag, produced either through air granulation 114b or water granulation 114c, are well-suited for use as a supplementary cementitious material (SCM) in Portland cement concrete. The rapid quenching inherent in these granulation processes 114b, 114c inhibits the formation of significant crystalline mineral structures, resulting in a predominantly amorphous or glassy material. This amorphous nature is highly advantageous for SCM applications because it typically exhibits greater hydraulic and / or pozzolanic reactivity when combined with Portland cement, compared to crystalline slags where minerals are allowed to form and which are generally less reactive as a cement.

[0036] The powdered modified EAF slag 123a can then be used as a cementitious component for forming mortars and concretes having an increased strength relative to ordinary Portland cement (OPC). For example, a combination of materials that showed the greatest potential in mortar cubes was a blend of 80% OPC, 10% LMF and 10% modified EAF slag. Mortar cubes made with this blend had compressive strengths that were 16%, 31% and 24% greater than conventional OPC at 7, 14, and 28 days respectively. Furthermore, this granulated material 121b, 121c is easier to grind to the required fineness (e.g., 90% passing 45 microns), leading to reduced energy consumption in processing as the amorphous molecules are not as tightly bound compared to atoms or molecules within the crystalline structures formed by slow-cooling. When used as an SCM, the ground granulated slag can replace a portion, often between 0 to 50%, of the Portland cement in concrete mixes. This not only contributes to enhanced mechanical properties such as compressive strength and improved long-term durability of the concrete, but also offers significantenvironmental benefits by reducing the clinker content, thereby lowering the overall carbon footprint associated with the concrete.

[0037] Lab testing concluded that the granulated modified EAF slag formed according to the present disclosure was at least four times easier to grind than unmodified EAF slag and that when combined with ground limestone and gypsum, mortar cubes were produced with good strengths. Furthermore, testing showed that when the modified EAF slag was ground and cured with CO2, this process produced a block that had comparable mechanical properties to conventional block products cured using CO2.

[0038] The terminology used herein is for the purpose of describing particular example configurations only and is not intended to be limiting. As used herein, the singular articles “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. Additional or alternative steps may be employed.

[0039] When an element or layer is referred to as being “on,” “engaged to,” “connected to,” “attached to,” or “coupled to” another element or layer, it may be directly on, engaged, connected, attached, or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” “directly attached to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0040] The terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and / or sections. These elements, components, regions, layers and / or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as“first,” “second,” and other numerical terms do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example configurations.

[0041] The foregoing description has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular configuration are generally not limited to that particular configuration, but, where applicable, are interchangeable and can be used in a selected configuration, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

Claims

CLAIMSWhat is claimed is:

1. A binder material produced by a process comprising: receiving an Electric Arc Furnace (EAF) slag; chemically modifying the EAF slag to achieve a target chemistry suitable for binder applications; slow cooling the chemically modified EAF slag to promote the formation of a mineralized and crystallized structure; and grinding the slow-cooled slag to form a powdered binder material.

2. The binder material of claim 1, wherein chemically modifying the EAF slag further comprises determining slag suitability by comparing historical slag chemistry data to the target chemistry using a compositional diagram, and determining the ease and cost of modifying the slag chemistry using a mass balance and economic model.

3. The binder material of claim 1, wherein chemically modifying the EAF slag further comprises determining a combination of reagents to add to the EAF slag, the reagents selected from the group consisting of Aluminum, Ladle Metallurgical Furnace (LMF) slag, silica sand, glass, lime, calcium carbide, bio-char, fly-ash, bottom ash, and combinations thereof.

4. The binder material of claim 1, wherein chemically modifying the EAF slag further comprises: metering a base dose of selected reagents into a slag transporting vessel contemporaneously as liquid slag is received, at a prescribed rate of approximately 1 to 5 tons per minute; performing a rapid slag analysis of the slag during or after the base dose addition using laser spectrometry or other quick method; and performing a final reagent dosing based on the rapid slag analysis to achieve the target chemistry.

5. The binder material of claim 4, wherein chemically modifying the EAF slag further comprises agitating the slag in the slag transport vessel after the final reagent dosing, using a mechanical mixer designed for high temperatures or by pneumatic stirring with compressed oxygen blown into the liquid slag with a lance.

6. The binder material of claim 1, wherein quenching the chemically modified EAF slag by slow cooling comprises pouring the molten slag into an open pit and allowing it to cool under ambient conditions, optionally with a water spray applied after pouring to control dust or manage the cooling rate.

7. The binder material of claim 6, wherein the process further comprises, after the pouring the molten slag into an open pit and before grinding performing coarse metal recovery by magnetic separation to remove metallic particles larger than approximately two inches.

8. The binder material of claim 6, wherein the process further comprises crushing the pit- cooled slag to a size less than approximately one inch, followed by a further magnetic separation to remove metallic pieces larger than approximately a half inch.

9. The binder material of claim 1, wherein grinding the slow-cooled slag comprises grinding to a fineness where at least 90% of the powdered binder material passes through a 45-micron sieve.

10. The binder material of claim 8, wherein the process further comprises performing magnetic separation during the grinding to remove metallic pieces larger than approximately 0.05 inches.

11. A supplemental cementitious product produced by a process comprising:(a) receiving an Electric Arc Furnace (EAF) slag;(b) chemically modifying said EAF slag to achieve a target chemistry suitable for supplemental cementitious product applications, enhancing its suitability for use in Portland cement systems;(c) quenching the chemically modified EAF slag by rapid granulation to promote the formation of a predominantly amorphous, glassy structure; and(d) grinding the granulated slag to form a fine powdered supplemental cementitious product.

12. The supplemental cementitious product of claim 11, wherein chemically modifying said EAF slag in step (b) further comprises determining slag suitability for supplemental cementitious product applications by comparing slag chemistry data to said target chemistry, wherein said target chemistry is optionally equivalent to that of Granulated Blast Furnace Slag (GBFS), using a compositional diagram, and utilizing a mass balance and economic model to determine the feasibility of said chemical modification.

13. The supplemental cementitious product of claim 11, wherein chemically modifying said EAF slag in step (b) further comprises determining a combination of reagents to add to said EAF slag, said reagents selected from the group consisting of Aluminum, Ladle Metallurgical Furnace (LMF) slag, silica sand, glass, lime, calcium carbide, bio-char, fly-ash, bottom ash, and combinations thereof, to achieve said target chemistry.

14. The supplemental cementitious product of claim 11, wherein chemically modifying said EAF slag in step (b) further comprises:(i) metering a base dose of selected reagents into a slag transporting vessel contemporaneously as liquid slag is received;(ii) performing a rapid slag analysis of the slag during or after said base dose addition; and(iii) performing a final reagent dosing based on said rapid slag analysis to achieve said target chemistry, optionally with agitation of the molten slag to ensure mixing.

15. The supplemental cementitious product of claim 11, wherein quenching by rapid granulation in step (c) comprises air granulation, wherein the molten slag is directed over a stream of air having a pressure of approximately 20 to 60 psi and an air flow rate of approximately 10,000 to 20,000 cubic feet per minute (cfm) per ton per minute of slag flow rate.

16. The supplemental cementitious product of claim 11, wherein quenching by rapid granulation in step (c) comprises water granulation, wherein the molten slag is directed into a stream of water having a pressure of approximately 20 to 40 psi and a water flow rate of approximately 1,200 to 2,400 gallons per minute (gpm) per ton per minute of slag flow rate.

17. The supplemental cementitious product of claim 11, wherein grinding the granulated slag in step (d) comprises grinding to a fineness where at least 90% of the powdered supplemental cementitious product passes through a 45-micron sieve, and optionally performing magnetic separation during said grinding to remove metallic pieces.

18. The supplemental cementitious product of claim 11 , wherein the predominantly amorphous, glassy structure formed by said rapid granulation in step (c) imparts enhanced hydraulic and / or pozzolanic reactivity to the powdered supplemental cementitious product when used in Portland cement systems.

19. The supplemental cementitious product of claim 11, wherein the powdered supplemental cementitious product is suitable for replacing up to approximately 50% by weight of Portland cement in concrete formulations.

20. The supplemental cementitious product of claim 19, wherein the replacement of Portland cement with said powdered supplemental cementitious product in concrete formulations contributes to one or more of: enhanced compressive strength of the resulting concrete, improved durability of the resulting concrete, and a reduction in the overall carbon footprint of the concrete.

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