STEEL SLAG ABRASIVE MATERIALS FOR BLASTING

Abstract

Systems and methods for producing a blasting medium from a slag and using the blasting medium. A slag produced during steel making processes is poured at a high temperature. The poured slag is then further processed to produce the blast medium. The blasting medium is used to clean a surface via blasting.

Claims

1. A method of producing a blasting medium, the method comprising: pouring, at a temperature of 1300 to 1900 C., a slag obtained from a steel making process; and processing the slag to produce the blasting medium.

2. A method of abrasive blasting, the method comprising: pouring, at a temperature of 1300 to 1900 C., a slag obtained from a steel making process; processing the slag to produce a blasting medium; and cleaning a surface by blasting the blasting medium on the surface.

3. The method of claim 2, wherein the processing step comprises: cooling the slag to form a crystalline slag; and atomizing the crystalline slag to produce a blasting medium comprising slag particles.

4. The method of claim 3, wherein the slag particles have a particle size in a range of 50 to 500 microns.

5. The method of claim 3, wherein the atomizing includes grinding.

6. The method of claim 3, wherein the crystalline slag is substantially in cubical shape.

7. The method of claim 3, wherein the cooling includes air cooling.

8. The method of claim 2, wherein the pouring is conducted at 1600 C.

9. The method of claim 2, wherein the blasting is conducted with a gas pressure of 3.5 to 9 bar.

10. The method of claim 2, wherein the blasting of the blasting medium is conducted using a compressed gas.

11. The method of claim 2, wherein the slag includes 15 to 30 wt. % FeO and Fe.sub.2O.sub.3, 30 to 50 wt. % CaO, 6 to 12 wt. % MgO, 10 to 20 wt. % SiO, and 5 to 10 wt. % Al.sub.2O.sub.3.

12. The method of claim 2, wherein the blasting is configured to de-scale steel, deburr a material, shot-peen a material, and/or remove paint from a surface.

13. The method of claim 2, wherein the blasting medium has a hardness of 6 to 8 Mohs.

14. The method of claim 2, wherein the blasting medium includes particles in fine shape, nominal shape, coarse shape, or combinations thereof.

15. A method of abrasive blasting, the method comprising: pouring, at a temperature of 1300 to 1900 C., a slag formed in an electric arc furnace in a steel making process; cooling the slag to form a crystalline slag; atomizing the crystalline slag to produce a blasting medium comprising slag particles with a particle size in a range of 50 to 500 microns; and cleaning a surface by blasting the blasting medium on the surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] For a more complete understanding, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

[0023] FIG. 1 shows a schematic diagram for a system for producing and using a blasting medium and, according to embodiments of the disclosure; and

[0024] FIG. 2 shows a method of abrasive blasting, according to embodiments of the disclosure.

DETAILED DESCRIPTION OF THE DISCLOSURE

[0025] 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 disclosure 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, none 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 disclosure are discussed in further detail in the following sections.

A. System for Producing a Blasting Medium

[0026] In embodiments of the disclosure, 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.

[0027] According to embodiments of the disclosure, system 100 includes pouring facility 101 configured to pour slag from a molten bath of a steel making unit. In embodiments of the disclosure, 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 disclosure, the pouring facility is configured to pour the slag at a high temperature in a range of 1300 to 1900 C.

[0028] According to embodiments of the disclosure, system 100 includes cooling unit 102 configured to cool the poured slag to form a crystalline slag. In embodiments of the disclosure, 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.

[0029] According to embodiments of the disclosure, system 100 includes atomizer 103 configured to process the crystalline slag to form a blasting medium comprising slag particles. In embodiments of the disclosure, the slag particles have a particle size in a range of 50 to 500 m. In embodiments of the disclosure, atomizer 103 may include a grinder, crusher, a hammer, or combinations thereof. According to embodiments of the disclosure, 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 disclosure, the air source includes a bottled gas or an air compressor. The blasting cabinet can include a container that holds the blast media. In embodiments of the disclosure, 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

[0030] 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 disclosure 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.

[0031] According to embodiments of the disclosure, as shown in block 201, method 200 includes pouring a slag obtained from a steel making process. In embodiments of the disclosure, 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 disclosure, the slag is produced in an electric arc and/or a ladle furnace. In embodiments of the disclosure, the slag includes 15 to 30 wt. % FeO and Fe.sub.2O.sub.3, 30 to 50 wt. % CaO, 6 to 12 wt. % MgO, 10 to 20 wt. % SiO, and 5 to 10 wt. % Al.sub.2O.sub.3.

[0032] According to embodiments of the disclosure, as shown in block 202, method 200 includes processing the slag to produce a blasting medium. In embodiments of the disclosure, as shown in block 203, the processing at block 202 includes cooling the slag to form a crystalline slag. In embodiments of the disclosure, at block 202, the cooling is conducted via air cooling. The air cooling may be performed in ambient air. In embodiments of the disclosure, cooling at block 202 may be conducted a cooling jacket, an air blower, a water sprayer, or combinations thereof. In embodiments of the disclosure, the crystalline slag is in cubical shape.

[0033] According to embodiments of the disclosure, 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 disclosure, the atomizing at block 204 includes grinding. In embodiments of the disclosure, the slag particles have a particle size in a range of 50 to 500 m and all ranges and values there between including ranges of 50 to 100 m, 100 to 150 m, 150 to 200 m, 200 to 250 m, 250 to 300 m, 300 to 350 m, 350 to 400 m, 400 to 450 m, and 450 to 500 m. In embodiments of the disclosure, 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 disclosure, the blasting medium includes particles in fine shape, nominal shape, coarse shape, or combinations thereof. In embodiments of the disclosure, the fine shape can have a size in a range of 40 to 200 m, the nominal shape can have a size in a range of 200 to 350 m, and the coarse shape can have a size in a range of 350 to 500 m.

[0034] According to embodiments of the disclosure, as shown in block 205, method 200 includes cleaning a surface by blasting the blasting medium on the surface. In embodiments of the disclosure, the blasting of the blasting medium at block 205 is conducted using a compressed gas. The blasting, in embodiments of the disclosure, 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.

[0035] Although embodiments of the present disclosure have been described with reference to blocks of FIG. 2, it should be appreciated that operation of the present disclosure is not limited to the particular blocks and/or the particular order of the blocks illustrated in FIG. 2. Accordingly, embodiments of the disclosure may provide functionality as described herein using various blocks in a sequence different than that of FIG. 2.

[0036] 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.

[0037] In the context of the present disclosure, 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.

[0038] 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 Fe.sub.2O.sub.3, 30 to 50 wt. % CaO, 6 to 12 wt. % MgO, 10 to 20 wt. % SiO, and 5 to 10 wt. % Al.sub.2O.sub.3. 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.

[0039] 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.

[0040] All embodiments described above and herein can be combined in any manner unless expressly excluded.

[0041] 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.