Classifications

• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
  • C21D1/62—Quenching devices

Definitions

• the present invention is directed toward an apparatus and method for quenching liquid slag and, more particularly, toward an improved apparatus and method for the quick quenching of liquid slag.
• Slag is a waste byproduct of the steel manufacturing process. Slag is typically generated in molten, or liquid, form by blast furnaces, electric arc furnaces, AOD (Argon Oxygen Decarburisation) furnaces, etc. The slag generated by these furnaces is at an extremely high temperature, and must be cooled in order for it to be able to be easily handled and disposed of or otherwise utilized.
• One known method of cooling liquid slag is to simply poor it onto the ground to cool. Once the liquid slag is cooled, the slag may be left on the ground where it was poured, or the slag can be picked up and moved to a new location where it may either be used for landfill purposes or further processed for other applications. As the liquid slag cools on the ground, it typically turns into a powdery material and generates an appreciable amount of dust.
• the cooled slag which is in a fine, powdery form, generates dust during handling, staging and stockpiling. During staging, the fine, powdery slag may need to be wet down to reduce the amount of dust generated. Handling and transporting the cooled slag in its powder form is typically difficult and may create an unsafe, or hazardous, working environment, especially in windy conditions.
• the present invention is directed toward overcoming one or more of the above-mentioned problems.
• the present invention includes an apparatus for quick quenching liquid slag, including a bay area for receiving the liquid slag and a water supply system for spraying, or quick quenching, the liquid slag provided on the bay area with water to cool the liquid slag.
• the bay area includes an angled and generally flat surface provided between first and second ends, with the first end defining a high end and the second end defining a low end, such that liquid slag provided to the bay area adjacent the first end will spread out and run down the bay area toward the second end.
• the water supply system is provided operatively above the bay area and applies water to the liquid slag on the bay area such that the liquid slag cools and turns into a crystalline form.
• the bay area is configured such that the liquid slag will spread out across the bay area and run down toward the trough area, but will stop running down the bay area before reaching the second end of the bay area (i.e., the trough area).
• the cooled, crystalline slag should be entirely present on the bay area.
• the water applies to the liquid slag is uniform in pressure and application, with a pressure typically in the range of 10-30 psi. It should be noted that this pressure range is exemplary only and other pressures may be utilized depending on the amount and type of the sprayers used without departing from the spirit and scope of the present invention.
• the bay area includes a continuous angle of inclination extending from the first end to the second end.
• the bay area includes a first area adjacent the first end having a first angle of inclination, and a second area adjacent the second end having a second angle of inclination, with the first angle of inclination being greater than the second angle of inclination.
• any configuration of angles of the bay area may be implemented without departing from the spirit and scope of the present invention, and will generally depend on the temperature and viscosity of the liquid slag, as well as the amount of slag being quenched.
• the angle(s) of inclination of the bay area will typically be chosen so that the layer of liquid slab will stop running down the bay area before reaching the second end thereof.
• the bay area is formed of one or more steel slabs, or may be formed of other materials capable of withstanding the high liquid slag temperatures.
• a dumping platform is provided adjacent the first end of the bay area, and the liquid slag is poured onto the bay area from the dumping platform.
• a trough area is provided adjacent the second end of the bay area, with the trough area receiving the run-off water applied to the liquid slag from the bay area.
• a sedimentation pond may be provided at an end of the trough area for receiving water from the trough area.
• the sedimentation pond includes a water drain and/or a pump which drains and/or pumps water from the sedimentation pond for recycling (e.g., further quenching or other applications).
• the trough area includes an access ramp accommodating a vehicle for removing the cooled and quenched crystalline slag from the bay area.
• a method according to the present invention is also provided for quick quenching liquid slag.
• the method includes the steps of providing a bay area having an angled and generally flat surface provided between first and second ends, with the first end defining a high end and the second end defining a low end, pouring liquid slag onto the bay area adjacent the first end, such that the liquid slag spreads out across the bay area surface and runs down the bay area toward the second end, and applying water to the liquid slag on the bay area such that the liquid slag cools and turns into a crystalline form.
• the bay area is configured such that the liquid slag will spread out across the bay area and run down toward the trough area, but will stop running down the bay area before reaching the second end of the bay area (i.e., the trough area).
• the cooled, crystalline slag should be entirely present on the bay area.
• the water applied to the liquid slag is uniform in pressure and application, with a pressure typically in the range of 10-30 psi.
• a pressure typically in the range of 10-30 psi.
• other water pressures are contemplated and may be utilized without departing from the spirit and scope of the present invention.
• the run-off water from the bay area is collected in a trough provided adjacent the second end and routed to a sedimentation pond where it may be recycled for further quenching or other applications.
• the bay area includes a continuous angle of inclination extending from the first end to the second end.
• the bay area includes a first area adjacent the first end having a first angle of inclination, and a second area adjacent the second end having a second angle of inclination, ' with the first angle of inclination being greater than the second angle of inclination.
• any configuration of angles of the bay area may be implemented without departing from the spirit and scope of the present invention.
• the bay area is formed of one or more steel slabs, or may be formed of other materials capable of withstanding the high liquid slag temperatures.
• additional liquid slag may be poured onto the bay area on top of the previously cooled and quenched crystalline slag, and water is applied to the additional liquid slag on the bay area such that the additional liquid slag cools and turns into a crystalline form.
• a front-end loader, or other similar vehicle, may be used to remove the cooled and quenched crystalline slag from the bay area.
• Fig. 1 is a top view of an exemplary apparatus for quick quenching liquid slag in accordance with the present invention.
• Fig. 2 is a cross-sectional view of the exemplary apparatus shown in Fig. 1 taken along line A-A.
• the apparatus 10 generally includes a bay area 12 and a trough area 14.
• the liquid slag is cooled in the bay area 12 by the application of water under pressure, such that the cooled slag remains in the bay area 12.
• the trough area 14 receives the water running from the bay area 12 and directs it to a sedimentation pond 16, where the water can be recycled for further quenching or other applications.
• the bay area 12 generally includes a plurality of steel slabs 18 which are installed side by side to form a flat surface.
• Liquid slag (not shown) is poured onto the steel slabs 18 for cooling, and thus the steel slabs 18 need to be able to withstand the high temperature of the liquid slag.
• the steel slabs 18 are oriented generally at an angle, with the low end 19 adjacent the trough area 14, such that the liquid slag and the water applied to the liquid slag run down the steel slabs 18 toward the trough area 14.
• the bay area 12 is approximately 50 feet long and the trough area 14 is approximately 80 feet long. However, other lengths for these areas are contemplated.
• a dumping platform 20 is provided at the high end 21 of the steel slabs 18.
• the dumping platform 20 is typically made of concrete, and may be approximately 4-10 feet high. However, other heights are contemplated.
• Liquid slag (not shown) is transported to the dumping platform 20 via trucks, slag pot carriers or other appropriate vehicles and poured onto the steel slabs 18 of the bay area 12. The poured liquid slag will spread out across the steel slabs 18 and run down toward the trough area 14 due to the angle of inclination of the steel slabs 18.
• vertically oriented steel plates 22 are provided on opposite sides of the surface formed by the steel slabs 18.
• the steel slabs 18 have a width of approximately 24 feet across, which is typically sufficient to accommodate the poured liquid slag without resulting in excess slag at the edges. However, other widths for the steel slabs 18 are contemplated.
• the steel slabs 18 have two different angles of inclination extending from the dumping platform 20 to the trough area 14.
• a first area, shown generally at 24, is adjacent the dumping platform 20 and includes a first angle of inclination
• a second area, shown generally at 26, extends to the trough area 14 and includes a second angle of inclination.
• the first angle of inclination of the first area 24 is greater than the second angle of inclination of the second area 26.
• the angle(s) of inclination of the steel slabs 18 should be chosen so that the liquid slag will stop running down the steel slabs 18 before it reaches the trough area 14. This aids in removing the slag since all of the cooled and crystalline slag will remain on the bay area 12, and also helps alleviate a hazardous condition since if the liquid slag would trap any water remaining in the trough area an explosion may occur.
• the angle of inclination of the first area 24 is approximately 17°, while the angle of inclination of the second area 26 is approximately 5°.
• these angles are for illustrative purposes only, and other angles of inclination are contemplated without departing from the spirit and scope of the present invention.
• the steel slabs 18 may be oriented at one continuous angle, or may be arranged such that they have various different angles as they extend from the dumping platform 20 to the trough area 14. In one exemplary form of the present invention, the angle of inclination of the steel slabs 18 will tend to decrease as one moves away from the dumping platform 20 toward the trough area 14.
• any configuration of angles of inclination of the steel slabs 18 may be implemented without departing from the spirit and scope of the present invention.
• the only requirement is that the liquid slag spread out across the steel slabs 18 (a thin layer of liquid slag will cool more quickly) and run down toward the trough area 14, stopping before reaching the trough area 14.
• the angle(s) of inclination of the steel slabs 18 i.e., bay area 12
• the angle(s) of inclination of the steel slabs 18 i.e., bay area 12
• the temperature and viscosity of the slag will be more viscous than a lower temperature slag.
• the goal is to have the slag spread evenly and thinly across the steel slabs 18 and stop before reaching the end of the steel slabs 18.
• the steel slabs 18 i.e., bay area 12
• the steel slabs 18 should be made long enough so that the liquid slag stops running down the steel slabs 18 before reaching the trough area 14.
• the bay area 12 is approximately 50 feet long. However, others lengths are contemplated and generally will depend on the temperature, viscosity and amount of liquid slag being cooled.
• the liquid slag is poured onto the bay area 12 and spreads out across the surface formed by the steel slabs 18, it is hit with low pressure cold water via a water supply system 28.
• the water cools the liquid slag almost instantly (a thin layer of liquid slag will cool quicker than a thicker layer).
• the liquid slag is quickly cooled, or quenched, using the low pressure water, it turns into a crystalline, or glass-like, form. Since the cooled, crystalline slag should be present on the steel slabs 18 on the bay area 12, it can be easily removed using a front-end loader or other similar vehicle.
• the spray bars and nozzles which make up the water supply system 28, may be designed to contain the steam generated as the slag cools within the quenching area.
• the spray nozzles used may apply a cone-like spray of water onto the liquid slag.
• the spray bars and nozzles will be positioned to spray water over the entire surface of the steel slabs 18, and thus over all of the liquid slag being cooled. The spray forms an umbrella over the slag trapping any steam generated. This trapped steam will cool and turn back into water.
• the spray bars and nozzles may also be configured such that no steam is contained during the quenching process. Additionally, the nozzles can be installed along each side of the steel slabs 18 spraying water toward the liquid slag.
• the water applied to the liquid slag will be uniform in pressure and application.
• the present invention contemplates utilizing a low pressure water system ⁇ e.g., between approximately 10-30 psi) to apply a high volume of water (e.g., between approximately 800- 2000 gallons/minute) in order to appropriately quench the liquid slag.
• the amount of water needed to thoroughly cool the liquid slag will depend on a number of factors, such as, but not limited to, the temperature, viscosity and amount of liquid slag being cooled (typically the temperature of the slag will decrease from the time it is tapped until the time it is brought to the platform to be quenched), the angle of the steel slabs IS, the thickness of the liquid slag as it runs down the steel slabs 18, the temperature of the water (the water used to cool the slag may become warmer if the water is being recycled for use), melt shop practices which may affect the viscosity of the slag, etc.
• the water which is applied to the liquid slag continues to run down the steel slabs 18 and is received at the trough area 14.
• Berms 30 are formed on either side of the trough area 14 and channel the water as it flows down the trough area 14 ⁇ see Fig. 1).
• the berms 30 may be formed of any material and, in one form, are formed of slag or fine aggregate or other similar material.
• the trough area may be virtually any length and, in one form as shown in Fig. 2, is 80 feet in length.
• the sedimentation pond 16 is provided at an end of the trough area 14 and receives the water flowing down the trough area 14.
• a water drain or a sump pump 32 is provided which drains or pumps the water from the sedimentation pond 16, and may direct the water to an area where it can be recycled for further quenching or other applications.
• the drain/pump 32 will include a cover to prevent large debris from entering the drain/pump. It has been found that the water run off from the above-described quenching process is mostly clear and free of fine particles and, thus, the water may be recycled through a closed loop system and reused for further quenching with minimal mechanical and/or chemical treatment.
• the water from the quenched slag can also be directed to a unique pond or basin system where the water can be immediately pumped to the quenching spray bars.
• a larger pond or basin system that overflows one after the other or a cooling tower can be used to help the water cool down before being re-used to help increase the effectiveness of the water.
• the length of the bay area 12 should be such that the slag stops moving before reaching the low end 19 of the bay area 12.
• a second batch of liquid slag may be poured on top of the already cooled slag, and quenched with low pressure cold water in the manner previously described. In this case, the duration of quenching will be set to ensure that enough heat remains in the slag and steel slabs 18 to burn off all remaining water and moisture before dumping another layer of liquid slag over the previous one.
• the cooled slag and steel slabs 18 remain at a temperature of approximately 200-250 0 F to burn off any excess water or moisture remaining before dumping an additional batch of slag on top for cooling.
• other temperatures may be utilized without departing from the spirit and scope of the present invention.
• Cooling a number of batches of liquid slag on top of each other helps to reduce material handling costs, and a plurality of batches of liquid slag may be cooled on top of each other. Once a desired amount of slag has been cooled, it is removed from the steel slabs 18.
• a front- end loader, or other similar vehicle accesses the trough area 14 via a loader access ramp 34. The front-end loader will drive up the trough area 14 and remove the cooled liquid slag from the steel slabs 18.
• the cooled liquid slag which is in a granulated, or crystalline, form, may be used for a variety of purposes, including landfills, cementitious applications, or it may be further processed for other applications. In its crystalline form, the cooled slag generally has high cementitious and/or pozzolanic properties, making it particularly useful for cementitious applications.
• the spray bars and nozzles of the water supply system 2 S should be design to uniformly spray the liquid slag with water at a constant pressure and volume. Should water get under the hot liquid slag material, explosions may occur sending molten slag spraying into the air. Thus, care needs to be taken, and the spray bars and nozzles of the water supply system 28 designed, so that the low pressure water is applied uniformly over the liquid slag.
• a high pressure water may also be used without departing from the spirit and scope of the present invention, as long as care is taken to not get water under the liquid slag.
• the pressure of the water may be dictated by the specific nozzle design used.
• the bay area 12 be totally clear of water, puddles of water and moisture before dumping the liquid slag thereon or an explosion may occur. Additionally, the trough area 14 should, also be free of water or puddles of water in case the liquid slag runs off the bay area 12 and into the trough area 14.
• Liquid slag when properly sprayed with a high volume of water, should not generate dust, only steam.
• the spray bars and nozzles of the water supply system can be designed to contain the generated steam within the quenched area.
• the liquid slag changes properties when rapidly cooled. After the slag is quick quenched, it is in a vitreous and granulated form, instead of a fine and powdery form using prior art methodology.
• the quick quenched slag is very easy to break up and remove. • The quick quenched slag normally weighs less than regular slag.
• the quick quenched slag does generate minimal dust during handling, staging and/or stockpiling.
• the slag pot with the molten slag can be dumped over the other cooled slag several times before it is required to remove the quenched slag with a front-end loader or other similar vehicle.
• the quick quench apparatus and method of the present invention makes easy the segregation of slag and metallics.
• the quick quench apparatus and method of the present invention reduces possible dust emissions by approximately 90%.
• the present invention provides a cost effective apparatus and method for cooling liquid slag into a useful crystalline form. While the present invention has been described with particular reference to the drawings, it should be understood that various modifications can be made to the apparatus and method of the present invention without departing from the spirit and scope thereof.

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• Chemical & Material Sciences (AREA)
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• Crystallography & Structural Chemistry (AREA)
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• Organic Chemistry (AREA)
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• 2007
  • 2007-01-09 CA CA002636472A patent/CA2636472A1/en not_active Abandoned
  • 2007-01-09 WO PCT/US2007/000503 patent/WO2007081937A2/en not_active Ceased
  • 2007-01-09 CN CNA2007800061287A patent/CN101389775A/zh active Pending
  • 2007-01-09 EP EP07716443A patent/EP1977019A2/de not_active Withdrawn
  • 2007-01-09 US US11/651,332 patent/US20070158883A1/en not_active Abandoned
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