CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. Provisional Application No. 63/131,216, filed December 28, 2020, the contents of which are incorporated herein in its entirety.

FIELD OF INVENTION

[0002] The present invention generally relates to systems and processes for producing and using abrasive blasting media. More specifically, the present invention relates to a system and a method for producing and using a blasting medium comprising a slag.

BACKGROUND OF THE INVENTION

[0003] Blasting is a process of smoothing and cleaning a hard surface by forcing solid particles across that surface at a high speed, usually using a compressed gas. It is a useful procedure in a broad range of applications and industries including cleaning, deburring, preparing for powder-coating, de-rusting, shot-peening, and paint removal.

[0004] A blasting system generally includes an air source, a blasting cabinet, a dust collector, and a blasting medium. The air source usually includes a bottled gas or an air compressor. The blasting cabinet is a large container that holds the blast media which is funneled downward through a set of valves that allow the amount entering the system to be controlled. The air carries blasting media to travel through the blast hose and out of a nozzle of a handheld gun. The particles travel at high velocities and impact the object, stripping the surface. Conventionally, blasting media used in this process includes sand, glass beads, plastic, or other materials. However, these existing material for blasting media may not meet all the requirements for all applications and purposes. Furthermore, these conventional materials for blasting media may need to be purchased, further increasing the cost for blasting.

[0005] Overall, while systems and methods for making and using blast media exist, the need for improvements in this field persists in light of at least the aforementioned drawback for the conventional systems and methods. BRIEF SUMMARY OF THE INVENTION

[0006] A solution to at least some of the above mentioned problems associated with the systems and methods for blasting hard surfaces has been discovered. The solution resides in a method for producing a blasting medium from a slag that is generated during a steel making process. This can be beneficial in providing a supply of blasting medium from a waste product/by product with minimal to no cost. Furthermore, slag is a strong, dense, non-porous aggregate that can be in cubical shape, with high resistance to polishing, resulting in high effectiveness in abrasive blasting. Additionally, the slag used in the disclosed method can be poured at about 1600 °C and then air-cooled to form crystalline slag, resulting in high hardness of the slag. Therefore, the systems and the methods of the present invention provide a technical solution to at least some of the problems associated with the conventional systems and methods for abrasive blasting as mentioned above.

[0007] Embodiments of the invention include a method of producing a blasting medium. The method comprises pouring, at a temperature of 1300 to 1900 °C, a slag obtained from a steel making process. The method comprises processing the slag to produce the blasting medium.

[0008] Embodiments of the invention include a method of abrasive blasting. The method comprises pouring, at a temperature of 1300 to 1900 °C, a slag obtained from a steel making process. The method comprises processing the slag to produce a blasting medium. The method comprises cleaning a surface by blasting the blasting medium on the surface.

[0009] Embodiments of the invention include a method of abrasive blasting. The method comprises pouring, at a temperature of 1300 to 1900 °C, a slag formed in an electric arc furnace in a steel making process. The method comprises cooling the slag to form a crystalline slag. The method comprises atomizing the crystalline slag to produce a blasting medium comprising slag particles with a particle size in a range of 50 to 500 pm. The method comprises cleaning a surface by blasting the blasting medium on the surface.

[0010] The following includes definitions of various terms and phrases used throughout this specification. [0011] For the purposes of this disclosure, “X, Y, and/or Z” can be construed as X only, Y only, Z only, or any combination of two or more items X, Y, and Z (e.g., XYZ, XY, XZ, YZ).

[0012] The terms “about” or “approximately” are defined as being close to as understood by one of ordinary skill in the art. In one non-limiting embodiment the terms are defined to be within 10%, preferably, within 5%, more preferably, within 1%, and most preferably, within 0.5%.

[0013] The terms “wt.%”, “vol.%” or “mol.%” refer to a weight, volume, or molar percentage of a component, respectively, based on the total weight, the total volume, or the total moles of material that includes the component. In a non-limiting example, 10 moles of component in 100 moles of the material is 10 mol.% of component.

[0014] The term “substantially” and its variations are defined to include ranges within 10%, within 5%, within 1%, or within 0.5%.

[0015] The terms “inhibiting” or “reducing” or “preventing” or “avoiding” or any variation of these terms, when used in the claims and/or the specification, include any measurable decrease or complete inhibition to achieve a desired result.

[0016] The term “effective,” as that term is used in the specification and/or claims, means adequate to accomplish a desired, expected, or intended result.

[0017] The term “blasting medium,” as that term is used in the specification and/or claims, means a material that is in fine (particle) forms and used to be sprayed under high pressure against a surface.

[0018] The use of the words “a” or “an” when used in conjunction with the term “comprising,” “including,” “containing,” or “having” in the claims or the specification may mean “one,” but it is also consistent with the meaning of “one or more,” “at least one,” and “one or more than one.”

[0019] The words “comprising” (and any form of comprising, such as “comprise” and “comprises”), “having” (and any form of having, such as “have” and “has”), “including” (and any form of including, such as “includes” and “include”) or “containing” (and any form of containing, such as “contains” and “contain”) are inclusive or open-ended and do not exclude additional, unrecited elements or method steps.

[0020] The process of the present invention can “comprise,” “consist essentially of,” or “consist of’ particular ingredients, components, compositions, etc., disclosed throughout the specification.

[0021] The term “primarily,” as that term is used in the specification and/or claims, means greater than any of 50 wt.%, 50 mol.%, and 50 vol.%. For example, “primarily” may include 50.1 wt.% to 100 wt.% and all values and ranges there between, 50.1 mol.% to 100 mol.% and all values and ranges there between, or 50.1 vol.% to 100 vol.% and all values and ranges there between.

[0022] Other objects, features and advantages of the present invention will become apparent from the following figures, detailed description, and examples. It should be understood, however, that the figures, detailed description, and examples, while indicating specific embodiments of the invention, are given by way of illustration only and are not meant to be limiting. Additionally, it is contemplated that changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. In further embodiments, features from specific embodiments may be combined with features from other embodiments. For example, features from one embodiment may be combined with features from any of the other embodiments. In further embodiments, additional features may be added to the specific embodiments described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] For a more complete understanding, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

[0024] FIG. 1 shows a schematic diagram for a system for producing and using a blasting medium, according to embodiments of the invention; and

[0025] FIG. 2 shows a method of abrasive blasting, according to embodiments of the invention.

DETAILED DESCRIPTION OF THE INVENTION [0026] Currently, abrasive blasting is conducted using a blasting system that generally includes an air source, a blasting cabinet, a dust collector, and a blasting medium. The blasting medium is carried by the air source (e.g., compressed gas) through a nozzle gun at a high velocity to impact a hard surface. The most commonly used blasting media can include sand, glass beads, plastic, or other materials, which need to be purchased, thereby increasing the cost for blasting. Additionally, the commonly used blasting media may not meet all the requirements for blasting various types of surfaces. The present invention provides a solution to at least some of these problems. The solution is premised on a system and method for producing and using a blasting medium that includes using a slag that is produced during a steel making process to make the blasting medium. The slag can be provided from a steel production plant with minimal to no cost, thereby reducing the cost for abrasive blasting. Additionally, the slag used in the disclosed method can be poured at about 1600 °C and then air-cooled to form crystalline slag, resulting in high hardness of the slag. Moreover, the slag is a strong, dense, non-porous aggregate that can be in cubical shape, with high resistance to polishing, resulting in high effectiveness in abrasive blasting. These and other non-limiting aspects of the present invention are discussed in further detail in the following sections.

A. System for producing a blasting medium

[0027] In embodiments of the invention, the system for producing a blasting medium includes a slag pouring facility, and a slag processing facility. With reference to FIG. 1, a schematic diagram is shown for system 100, which is used for producing a blasting medium from a slag.

[0028] According to embodiments of the invention, system 100 includes pouring facility 101 configured to pour slag from a molten bath of a steel making unit. In embodiments of the invention, the slag floats on top of molten bath of steel, and the slag is separated from the steel by pouring the top content of the molten bath of steel. In embodiments of the invention, the pouring facility is configured to pour the slag at a high temperature in a range of 1300 to 1900 °C.

[0029] According to embodiments of the invention, system 100 includes cooling unit 102 configured to cool the poured slag to form a crystalline slag. In embodiments of the invention, cooling unit 102 includes a container for cooling the poured slag in ambient air. Cooling unit 102 may further include a cooling structure comprising a cooling jacket, an air blower, water spray, or combinations thereof (not shown).

[0030] According to embodiments of the invention, system 100 includes atomizer 103 configured to process the crystalline slag to form a blasting medium comprising slag particles. In embodiments of the invention, the slag particles have a particle size in a range of 50 to 500 pm. In embodiments of the invention, atomizer 103 may include a grinder, crusher, a hammer, or combinations thereof. According to embodiments of the invention, system 100 may further include blasting system 104 comprising an air source, a blasting cabinet, a dust collector, and a blasting medium. In embodiments of the invention, the air source includes a bottled gas or an air compressor. The blasting cabinet can include a container that holds the blast media (not shown). In embodiments of the invention, the air from the air source is configured to carry blasting media to travel through a blast hose and out of a nozzle.

B. Method of abrasive blasting

[0031] Methods of producing a blasting medium using a slag produced from steel making and using the blasting medium for abrasive blasting have been discovered. As shown in FIG. 2, embodiments of the invention include method 200 for abrasive blasting with a blasting medium produced from a slag. Method 200 may be implemented by system 100, as shown in FIG. 1 and described above.

[0032] According to embodiments of the invention, as shown in block 201 , method 200 includes pouring a slag obtained from a steel making process. In embodiments of the invention, pouring at block 201 is conducted when the slag is at temperature of 1300 to 1900 °C and all ranges and values there between including ranges of 1300 to 1350 °C, 1350 to 1400 °C, 1400 to 1450 °C, 1450 to 1500 °C, 1500 to 1550 °C, 1550 to 1600 °C, 1600 to 1650 °C, 1650 to 1700 °C, 1700 to 1750 °C, 1750 to 1800 °C, 1800 to 1850 °C, and 1850 to 1900 °C. Preferably, the pouring at block 201 can be conducted when the slag is at 1600 °C. In embodiments of the invention, the slag is produced in an electric arc and/or a ladle furnace. In embodiments of the invention, the slag includes 15 to 30 wt.% FeO and Fe2Ch, 30 to 50 wt.% CaO, 6 to 12 wt.% MgO, 10 to 20 wt.% SiO, and 5 to 10 wt.% AI2O3.

[0033] According to embodiments of the invention, as shown in block 202, method 200 includes processing the slag to produce a blasting medium. In embodiments of the invention, as shown in block 203, the processing at block 202 includes cooling the slag to form a crystalline slag. In embodiments of the invention, at block 202, the cooling is conducted via air cooling. The air cooling may be performed in ambient air. In embodiments of the invention, cooling at block 202 may be conducted a cooling jacket, an air blower, a water sprayer, or combinations thereof. In embodiments of the invention, the crystalline slag is in cubical shape.

[0034] According to embodiments of the invention, as shown in block 204, the processing at block 202 includes atomizing the crystalline slag to produce a blasting medium comprising slag particles. In embodiments of the invention, the atomizing at block 204 includes grinding. In embodiments of the invention, the slag particles have a particle size in a range of 50 to 500 pm and all ranges and values there between including ranges of 50 to 100 pm, 100 to 150 pm, 150 to 200 pm, 200 to 250 pm, 250 to 300 pm, 300 to 350 pm, 350 to 400 pm, 400 to 450 pm, and 450 to 500 pm. In embodiments of the invention, the blasting medium has a hardness of 6 to 8 Mohs and all ranges and values there between including ranges of 6 to

6.2 Mohs, 6.2 to 6.4 Mohs, 6.4 to 6.6 Mohs, 6.6 to 6.8 Mohs, 6.8 to 7.0 Mohs, 7.0 to 7.2 Mohs,

7.2 to 7.4 Mohs, 7.4 to 7.6 Mohs, 7.6 to 7.8 Mohs, and 7.8 to 8.0 Mohs. In embodiments of the invention, the blasting medium includes particles in fine shape, nominal shape, coarse shape, or combinations thereof. In embodiments of the invention, the fine shape can have a size in a range of 40 to 200 pm, the nominal shape can have a size in a range of 200 to 350 pm, and the coarse shape can have a size in a range of 350 to 500 pm.

[0035] According to embodiments of the invention, as shown in block 205, method 200 includes cleaning a surface by blasting the blasting medium on the surface. In embodiments of the invention, the blasting of the blasting medium at block 205 is conducted using a compressed gas. The blasting, in embodiments of the invention, is conducted with a gas pressure of 3.5 to 9 bar and all ranges and values there between including ranges of 3.5 to 4.0 bar, 4.0 to 4.5 bar, 4.5 to 5.0 bar, 5.0 to 5.5 bar, 5.5 to 6.0 bar, 6.0 to 6.5 bar, 6.5 to 7.0 bar, 7.0 to 7.5 bar, 7.5 to 8.0 bar, 8.0 to 8.5 bar, and 8.5 to 9.0 bar. The blasting can be configured to de-scale steel, deburr a material, shot-peen a material, and/or remove paint from a surface.

[0036] Although embodiments of the present invention have been described with reference to blocks of FIG. 2, it should be appreciated that operation of the present invention is not limited to the particular blocks and/or the particular order of the blocks illustrated in FIG. 2. Accordingly, embodiments of the invention may provide functionality as described herein using various blocks in a sequence different than that of FIG. 2. [0037] The systems and processes described herein can also include various equipment that is not shown and is known to one of skill in the art of chemical processing. For example, some controllers, piping, computers, valves, pumps, heaters, thermocouples, pressure indicators, mixers, heat exchangers, and the like may not be shown.

[0038] In the context of the present invention, at least the following 15 embodiments are described. Embodiment 1 is a method of producing a blasting medium. The method includes pouring, at a temperature of 1300 to 1900 °C, a slag obtained from a steel making process. The method further includes processing the slag to produce the blasting medium.

[0039] Embodiment 2 is a method of abrasive blasting. The method includes pouring, at a temperature of 1300 to 1900 °C, a slag obtained from a steel making process. The method further includes processing the slag to produce a blasting medium. The method still further includes cleaning a surface by blasting the blasting medium on the surface. Embodiment 3 is the method of embodiment 2, wherein the processing step includes cooling the slag to form a crystalline slag. The method further includes atomizing the crystalline slag to produce a blasting medium containing slag particles. Embodiment 4 is the method of any of embodiments 2 and 3, wherein the slag particles have a particle size in a range of 50 to 500 microns. Embodiment 5 is the method of any of embodiments 2 to 4, wherein the atomizing includes grinding. Embodiment 6 is the method of any of embodiments 2 to 5, wherein the crystalline slag is substantially in cubical shape. Embodiment 7 is the method of any of embodiments 2 to 6, wherein the cooling includes air cooling. Embodiment 8 is the method of any of embodiments 2 to 7, wherein the pouring is conducted at 1600 °C. Embodiment 9 is the method of any of embodiments 2 to 8, wherein the blasting is conducted with a gas pressure of 3.5 to 9 bar. Embodiment 10 is the method of any of embodiments 2 to 9, wherein the blasting of the blasting medium is conducted using a compressed gas. Embodiment 11 is the method of any of embodiments 2 to 10, wherein the slag includes 15 to 30 wt.% FeO and Fe2O3, 30 to 50 wt.% CaO, 6 to 12 wt.% MgO, 10 to 20 wt.% SiO, and 5 to 10 wt.% AI2O3. Embodiment 12 is the method of any of embodiments 2 to 11, wherein the blasting is configured to de-scale steel, deburr a material, shot-peen a material, and/or remove paint from a surface. Embodiment 13 is the method of any of embodiments 2 to 12, wherein the blasting medium has a hardness of 6 to 8 Mohs. Embodiment 14 is the method of any of embodiments 2 to 13, wherein the blasting medium includes particles in fine shape, nominal shape, coarse shape, or combinations thereof. [0040] Embodiment 15 is a method of abrasive blasting, the method including pouring, at a temperature of 1300 to 1900 °C, a slag formed in an electric arc furnace in a steel making process. The method further includes cooling the slag to form a crystalline slag. The method still further includes atomizing the crystalline slag to produce a blasting medium containing slag particles with a particle size in a range of 50 to 500 microns. The method also includes cleaning a surface by blasting the blasting medium on the surface.

[0041] All embodiments described above and herein can be combined in any manner unless expressly excluded.

[0042] Although embodiments of the present application and their advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the embodiments as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the above disclosure, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.