Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F9/00—Making metallic powder or suspensions thereof
  • B22F9/02—Making metallic powder or suspensions thereof using physical processes
  • B22F9/06—Making metallic powder or suspensions thereof using physical processes starting from liquid material
  • B22F9/08—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying
  • B22F9/082—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying atomising using a fluid
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2/00—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic
  • B01J2/02—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic by dividing the liquid material into drops, e.g. by spraying, and solidifying the drops
  • B01J2/04—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic by dividing the liquid material into drops, e.g. by spraying, and solidifying the drops in a gaseous medium
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
  • F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
  • F27D17/001—Extraction of waste gases, collection of fumes and hoods used therefor
  • F27D17/002—Details of the installations, e.g. fume conduits or seals
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F9/00—Making metallic powder or suspensions thereof
  • B22F9/02—Making metallic powder or suspensions thereof using physical processes
  • B22F9/06—Making metallic powder or suspensions thereof using physical processes starting from liquid material
  • B22F9/08—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying
  • B22F9/082—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying atomising using a fluid
  • B22F2009/0832—Handling of atomising fluid, e.g. heating, cooling, cleaning, recirculating
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P10/00—Technologies related to metal processing
  • Y02P10/10—Reduction of greenhouse gas [GHG] emissions

Definitions

• the present disclosure relates to metal production processes and facilities, and particularly to the use of by-product off-gases for gas
• gases are conveyed from one part of the process to another for one of the following purposes :
• the off-gas may: A) Be laden with particulate;
• compositions e.g. similar to air, oxygen free (N 2 , H 2 0, C0 2 rich), fuel rich (CO, H 2 ) or sulfur rich (S0 2 ));
• C0 2 emission from metallurgical plants is an environmental concern, and all metals producers are under pressure to reduce their greenhouse gas emission.
• carbon dioxide reforming units have been used to convert the C0 2 -rich off-gas to a mixture of hydrogen and carbon monoxide (synthetic gas), which can then be used as a fuel in different processes (for example upstream dryer, calciner, furnace, or prereduction units).
• synthetic gas for example upstream dryer, calciner, furnace, or prereduction units.
• the C0 2 -rich gas needs to be preheated to above ⁇ 900°C, which represents an additional operating cost.
• Carbon dioxide is only one example of an emission which can cause environmental concerns. Emissions from metallurgical plants may include a wide variety of other undesirable components, including gases and particulate solids, which are of concern when released into the environment. Furthermore, the reduction or removal of these undesirable components from the off-gases of a metallurgical plant typically requires costly equipment and processes.
• undesirable gases which may be contained in the off- gases of metallurgical plants include C0 2 , sulphur-containing species such as S0 2 , S0 3 , and H 2 S nitrogen oxides (NO x ) such as NO and N0 2 , phosphorus- containing gases, fluorides (such as HF and SiF 4 ) and/or organic species such as furans and dioxins.
• undesirable particulate solids include dust, which must typically be removed from off-gases.
• Slag is another by-product of metal production processes conducted in metallurgical furnaces.
• Slag typically comprises a mixture of metal oxides with silicon dioxide, and is produced in amounts ranging from roughly 10 percent to several times the amount of metal produced by the process.
• a process for preparing a granular product comprising : (a) providing a molten material; (b) feeding the molten material to a dispersion apparatus; (c) feeding a gas to the dispersion apparatus, wherein the gas is a by-product off-gas; (d) contacting the gas with the molten material in the dispersion apparatus, whereby the molten material is dispersed and solidified by contact with the gas to form said granular product.
• a system for preparing a granular product comprising : (a) a metallurgical furnace containing a molten material selected from one or more of molten metal and molten slag; (b) a gas atomization plant located proximate to the metallurgical furnace; (c) a gas supply system for supplying a by-product off-gas to the gas atomization plant; (d) a molten material supply system for transporting the molten material from the metallurgical furnace to the gas atomization plant.
• Figure 1 illustrates a portion of a process flow diagram in accordance with a first embodiment disclosed herein.
• Figure 2 illustrates a portion of a process flow diagram in accordance with a second embodiment disclosed herein.
• B Elimination of furnace, metal tapping, calcine transfer, dust control, and reduction equipment fans. Instead, the atomization fan can evacuate gases from these processes and use them for atomization .
• C Elimination of operating expenditures associated with the use of furnace, metal tapping, calcine transfer, dust control, and reduction equipment fans, in contrast to system that atomize slag and/or metal with air.
• Figure 1 illustrates a portion of a process flow diagram according to a first embodiment of the invention.
• the flow diagram partially illustrates a process and system for production of metal by a metallurgical furnace 10 which includes a plurality of electrodes 12 for supplying heat to produce and maintain a layer of molten metal 14 and a layer of molten slag 16 within the furnace chamber.
• Figure 1 shows that the furnace includes a slag tap hole 18 which communicates with the molten slag layer 16 and a molten metal tap hole 20 which communicates with the molten metal layer 14.
• Molten slag is periodically tapped from the furnace 10 through the slag tap hole 18, and is tapped directly into a movable slag vessel or a slag launder or runner, in which the molten slag is transported to another area of the plant. During transport, the slag is maintained in a molten state. The transportation of the molten slag in a slag vessel or launder is
• the furnace 10 in Figure 1 is at least partially cooled by air. More specifically, the bottom wall and lower side wall of furnace 10 are cooled by air.
• furnace cooling air is provided to the furnace by a fan or blower.
• the process and system according to the present embodiment eliminates such fans or blowers.
• the furnace cooling air becomes heated as it cools the bottom wall and side wall of the furnace.
• the flow of exhausted cooling air from the furnace bottom wall and lower side wall is represented by arrows 24 and 26, respectively.
• the heated cooling air is exhausted to the atmosphere.
• the system according to the present embodiment also includes a gas atomization plant 28 to atomize the molten slag and produce slag granules suitable for use in commercial products such as proppants and/or roofing granules.
• the gas atomization plant 28 is located in close proximity to the metallurgical furnace 10, and receives the molten slag from furnace 10 via a slag vessel or launder, as represented by arrow 22.
• the molten slag is atomized inside plant 28 by a gas flow from an induced draft (ID) fan 30, wherein the supply of atomizing gas from the ID fan 30 to gas atomization plant 28 is represented by arrow 32 in Figure 1.
• ID fan 30 contacts a falling stream of molten slag in the atomization chamber of gas atomization plant 28, the molten slag is simultaneously separated into droplets and cooled to a solid state, thereby forming solid slag granules which fall to the bottom of the chamber.
• the gas input to gas atomization plant 28 is instead routed through an air blower (not shown but replaces the ID fan) and may comprise air at ambient temperature and pressure.
• the gas input to the ID fan 30 comprises exhausted off-gases from the furnace bottom wall and/or the lower side wall, as represented by arrow 24 and/or 26. Such exhausted off-gases could not be fed to the blower utilized in current air atomization plants as they are hot and dirty.
• the gas input to ID fan 30 comprises the combined off-gas from the furnace bottom wall and the lower side wall, and therefore Figure 1 shows arrows 24 and 26 being combined to form arrow 34 which represents the off-gas input to the ID fan 30.
• the off-gas supplied to the gas atomization plant 28 by ID fan 30 includes heat extracted from the furnace, and therefore is at a temperature greater than ambient temperature.
• the ID fan 30 for supplying off-gas to the gas atomization plant 28 also draws air into the furnace cooling system . This permits the elimination of any fans for supplying cooling air to the furnace 10, thereby providing a reduction in capital expenses and operating costs.
• the use of the off-gas for atomization permits the elimination of a separate off-gas treatment system for the off-gas, and providing a further reduction in capital expenses and operating costs.
• air circulation through the furnace air cooling system and off-gas circulation to the gas atomization plant is provided by the same ID fan 30.
• the ID fan 30 may not necessarily need to be located between the furnace 10 and the gas atomization plant 28, but may instead be located upstream of the furnace 10 so as to blow cooling air to the furnace walls and to blow the heated air to the gas atomization plant 28.
• Figure 1 the solid slag granules produced by gas atomization plant 28 are represented by box 36 and their removal from the gas atomization plant 28 is represented by arrow 38.
• the off-gas used for atomization is exhausted by the gas atomization plant 28 as a slag granulation off-gas which is represented by box 40, and the removal of the off-gas from the gas atomization plant 28 is represented by arrow 42.
• the off-gas 40 contains heat extracted from the furnace side wall and bottom wall, and heat extracted from the molten slag. Therefore, use of the off-gas exhausted from the furnace cooling system in the gas atomization plant 28 upgrades the heat in the off-gas, thereby permitting its use in downstream process equipment for energy transfer.
• the hot off-gas 40 from gas atomization plant 28 may be processed to recover heat therefrom, or it may be fed to other process units which require heat, such as drying units, water pre-heating units, etc.
• Figure 2 illustrates a portion of a process flow diagram according to a second embodiment, in which the off-gas instead comprises off-gases exhausted from the interior of the furnace and/or from fume and dust capture hoods.
• the first and second embodiments have a number of common elements, and these common elements are identified in Figure 2 using like reference numerals. Furthermore, the above descriptions of these common elements apply equally to the second embodiment, unless otherwise indicated below.
• the embodiment of Figure 2 includes a metallurgical furnace 10 as described above, except that it also includes an off-gas port 50 for venting a by-product off-gas from the interior of the furnace 10.
• the vented furnace off-gas is represented by arrow 52 in Figure 2.
• at least a portion of the furnace off-gas may be collected in a fume and dust capture hood 54, and withdrawn therefrom to be conveyed to the gas atomization plant 28 through ID fan 30.
• Figure 2 shows arrows 56, 58, 34 to represent the flow of the off-gas from the fume and dust capture hood 54 to the ID fan 30.
• FIG. 1 shows arrows 52, 60, 58, 34 to represent the flow of the off-gas from the off-gas port 50 to the ID fan. It will be appreciated that all the off-gas, or a portion thereof, may be collected in hood 54 before it is conveyed to the gas atomization plant 28, and/or all or a portion of the off-gas may be directly conveyed from the furnace 10 to the gas atomization plant (through ID fan 30), or any combination thereof.
• the off-gas may be of varying composition, and this is further discussed below. Regardless of the composition of the off-gas used for atomization, it is important to emphasize that an important aspect of the present invention is the use of an induced draft fan 30 to withdraw off-gases (for example from the interior of the furnace or from the bottom of the furnace) and to supply the off-gases for atomization . This replaces a conventional blower which draws in ambient air and blows the air for atomization. This improvement is applicable to all embodiments disclosed herein.
• the off-gas may be depleted in oxidative species such as oxygen or may be substantially free of oxidative species.
• the extent of the oxidation is dependent on the composition of the off-gas, but this reduction in the level of oxidation can be realized from a variety of off-gases from a number of sources within the system, such as the off-gases which are vented from the furnace as in Figure 2, which may be depleted in oxygen and/or may include one or more gaseous by-products.
• Another important aspect of the present invention is that the use of the off-gas for atomization results in upgrading of the off-gas heat. This is an important benefit where it is desired to recover heat from the off-gas or use the off-gas in another process step where heat is required, e.g. in drying or preheating, and is realized in all embodiments disclosed herein.
• the off-gas supplied to the gas is the off-gas supplied to the gas
• atomization plant 28 for the purpose of atomizing molten metal or slag may be laden with particulates.
• Use of the process and system as described herein permit the elimination of a separate off-gas treatment system, and the particulate laden off-gas is supplied to the gas atomization plant 28 by ID fan 30 as described above in the first and second embodiments.
• the off-gas from the gas atomization plant 28 is treated as discussed above.
• atomization of metal/slag may use C0 2 -rich off-gases as the atomizing gas.
• C0 2 -rich off-gases as the atomizing gas.
• box 44 comprise a reformer for producing synthetic gas.
• Atomization of the metal/slag may also be conducted with off- gases containing one or more other undesirable components, defined herein as including gases and particulate solids which are of concern when released into the environment, and which typically must either be partially or completely removed by treatment of the off-gases.
• off- gases containing one or more other undesirable components defined herein as including gases and particulate solids which are of concern when released into the environment, and which typically must either be partially or completely removed by treatment of the off-gases.
• the undesirable components include one or more gases such as C0 2 , sulphur-containing species such as S0 2 , S0 3 , and H 2 S nitrogen oxides (NO x ) such as NO and N0 2 , phosphorus-containing gases, fluorides (such as HF and SiF 4 ) and/or organic species such as furans and dioxins.
• gases such as C0 2 , sulphur-containing species such as S0 2 , S0 3 , and H 2 S nitrogen oxides (NO x ) such as NO and N0 2
• phosphorus-containing gases such as HF and SiF 4
• organic species such as furans and dioxins.
• the reduction is brought about by dissolution of the undesirable component(s) in the molten metal/slag during the formation of said granular product in the atomization plant, such that a concentration of the undesirable component(s) in the hot off-gas of the gas atomization plant is less than a concentration of the undesirable component(s) in the off-gas supplied to the gas atomization plant. This may reduce the need for expensive equipment and processes to remove these undesirable components from the off-gas.
• the undesirable components include one or more gaseous organic species such as furans and dioxins.
• the reduction of the concentration of these organic species in the off-gas may be accomplished by combustion of the organic species by contact of the organic species with the molten metal/slag in the presence of oxygen in the off-gas and/or in the metal/slag.
• at least a portion of the gases produced by combusting the organic species in the gas atomization plant may become dissolved in the molten metal/slag during the formation of the granular product.
• the gas atomization plant may further function as an afterburner.
• the dust particles may become incorporated into the granular product during atomization of the molten metal/slag in the gas atomization plant. This may reduce the need for expensive equ ipment and processes to remove dust from the off-gas.
• the present invention permits the integration of one or more off-gas streams into the off-gas from the gas atomization plant. This permits a reduction in the off-gas treatment equipment in the system, resulting in reductions in both capital and operating expenditures, and this benefit is realized by all embodiments disclosed herein.
• molten metal tapped from furnace 10 through tap hole 20 may be granulated by gas atomization plant 28, rather than slag .
• Figure 2 includes a dotted line 62 representing the conveyance of molten metal from the tap hole 20 to the gas atomization apparatus 28, where the molten metal is granulated in exactly the same manner as described above for molten slag.
• this modification may also apply to the process flow diagram of Figure 1, relating to the first embodiment.
• the composition of the metal tapped from furnace 10 will of course depend on the specific metallurgical process being conducted therein .
• the molten metal tapped through tap hole 20 may comprise ferronickel (FeNi).
• FeNi ferronickel
• the processes and systems disclosed herein are not limited to any specific metallurgical processes.
• the processes and systems disclosed herein can be applied to the production of pig iron in an ironmaking blast furnace.
• the use of hot and/or dirty off-gases for atomization may require the ID fan 30 to comprise a dirty gas fan with radial blades which are capable of handling dirty off-gases rather than fresh air blowers with backwardly curved impeller blades. This applies to all embodiments disclosed herein.
• the off-gas supplied to the gas is the off-gas supplied to the gas
• the off-gas may be rich in gases such as N 2 , H 2 0 or C0 2 which will result in little or no oxidation of metals contained in the molten slag or molten metal during atomization.
• the furnace off-gases from FeCr smelters are rich in C0 2 and their use as atomizing gases may be particularly beneficial in the production of pig iron or other metals in which oxidation during atomization is to be avoided.
• the off- gas may be rich in fuel such as CO or H 2 , or may be rich in sulfur-containing species such as S0 2 .

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Environmental & Geological Engineering (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
• Furnace Details (AREA)
• Manufacture Of Metal Powder And Suspensions Thereof (AREA)

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• 2015
  • 2015-09-21 CA CA2961075A patent/CA2961075C/en not_active Expired - Fee Related
  • 2015-09-21 AU AU2015318566A patent/AU2015318566A1/en not_active Abandoned
  • 2015-09-21 BR BR112017005583A patent/BR112017005583A2/pt not_active IP Right Cessation
  • 2015-09-21 MX MX2017003520A patent/MX2017003520A/es unknown
  • 2015-09-21 EP EP15841438.3A patent/EP3194063A1/de not_active Withdrawn
  • 2015-09-21 CN CN201580050666.0A patent/CN106999884A/zh active Pending
  • 2015-09-21 RU RU2017110486A patent/RU2017110486A/ru not_active Application Discontinuation
  • 2015-09-21 KR KR1020177008906A patent/KR20170060029A/ko unknown
  • 2015-09-21 WO PCT/CA2015/050923 patent/WO2016041092A1/en active Application Filing
  • 2015-09-21 US US15/512,955 patent/US20170297113A1/en not_active Abandoned
  • 2015-09-21 JP JP2017514631A patent/JP2017527770A/ja active Pending
• 2017
  • 2017-03-16 DO DO2017000074A patent/DOP2017000074A/es unknown
  • 2017-03-21 CO CONC2017/0002625A patent/CO2017002625A2/es unknown

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