Classifications

• • 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
  • F27D3/00—Charging; Discharging; Manipulation of charge
  • F27D3/15—Tapping equipment; Equipment for removing or retaining slag
• • 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
  • F27D3/00—Charging; Discharging; Manipulation of charge
  • F27D3/15—Tapping equipment; Equipment for removing or retaining slag
  • F27D3/1509—Tapping equipment
  • F27D3/1527—Taphole forming equipment, e.g. boring machines, piercing tools
• • 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
  • F27D3/00—Charging; Discharging; Manipulation of charge
  • F27D3/15—Tapping equipment; Equipment for removing or retaining slag
  • F27D3/1545—Equipment for removing or retaining slag

Definitions

• the present invention relates to an improved method for removing slag from a furnace. More particularly, the present invention relates to a method for removing slag from a stationary furnace, such as a top entrant submerged lance furnace. The present invention also extends to apparatus used in the method. BACKGROUND TO THE INVENTION
• Pyrometallurgical processes typically involve the formation of a slag layer. It is frequently necessary to remove slag from furnaces. There have been a number of different methods for removing slag from furnaces. For example, in tilting furnaces or moving furnaces, it is normal to provide an aperture at a position located above the level of the slag in the furnace during normal use of the furnace. The furnace may then be tipped or rotated so that the slag pours out through the aperture.
• a tap opening is provided in the side of the furnace.
• Such tap openings comprise circular openings formed in the furnace wall.
• the tap opening is normally closed off using clay or mud that is injected into the opening using a clay gun or a mud gun.
• the clay or mud form an effective barrier that prevents leakage of molten furnace products through the tap opening.
• a drill is used to drill a tap hole through the clay or mud.
• the drill normally has a diameter that is only slightly smaller than the diameter of the tap opening. When the drill is removed from the tap hole, the slag can pour out through the tap hole.
• the tap hole is closed off using a mud gun or a clay gun.
• the slag is removed from the furnace on an intermittent or batch basis.
• a tap opening is provided in the side wall of the furnace.
• a slag receiving receptacle is mounted to the outside of the furnace so that any slag that passes through the tap opening is received in the receptacle.
• the slag in the receptacle fills the receptacle, the slag overflows a weir in the receptacle and is collected or transported to another location.
• the slag may be tapped from the furnace on a continuous basis. It is generally not necessary to close the tap opening with clay or mud.
• Top entrant submerged lance furnaces are used in the production of metals by pyrometallurgical processes.
• Top entrant submerged lance furnaces comprise a stationary furnace vessel, normally lined with refractory material.
• the fuel and air or oxygen is normally injected into the furnace charge via a lance that is inserted into the furnace charge from above.
• air or oxygen is injected through the lance, the air or oxygen causes agitation of the furnace charge. Therefore, the molten furnace contents are violently stirred in top entrant submerged lance furnaces.
• An example of a top entrant submerged lance furnace is the ISASMELTTM furnace as manufactured and sold by the present applicant.
• ISASMELTTM furnace installations are currently used in the production of copper and lead. Other metals may also be produced using ISASMELTTM furnace installations.
• PCT/AU2006/001460 we describe a method for producing lead in which a lead ore or concentrate is fed to an ISASMELTTM furnace. This results in the formation of lead bullion and a lead slag.
• the lead slag is removed from the furnace, formed into lumps (such as by feeding the lead slag to a caster) and the lumps of lead slag are then fed as a feed material to a blast furnace.
• the lead slag is converted into lead bullion and a discard slag in the blast furnace.
• the present invention provides a method for tapping slag from a stationary furnace comprising:
• the stationary furnace may comprise a top entrant submerged lance furnace.
• the size of the hole in the clay or mud through which the slag flows may be adjusted by widening the opening or by removing solidified slag from the periphery of the opening. In one embodiment the size of the hole in the clay or mud through, which the slag flows may be adjusted by using a jack hammer or a pick tool to widen the opening or to remove solidified slag from the opening.
• the tap opening in the furnace may comprise a generally rectangular opening. The generally rectangular opening may have rounded corners.
• the size of the tap hole is adjusted by expanding a horizontal width of the tap hole in the clay or mud.
• the method may further comprise the step of monitoring the flow of slag from the furnace and, if the flow of slag is too low, widening the opening, and if the slag flow is too high, allowing slag to build up around the opening to thereby narrow the opening or packing further mud or clay into the opening to thereby narrow the opening.
• the flow of slag from the furnace may be monitored by visual inspection carried out by an operator of the furnace. Alternatively, the flow of slag from the furnace may be monitored using an automated flow rate monitoring means.
• the size of the hole through which the slag flows may be enlarged by using a jack hammer or pick tool.
• the jack hammer or pick tool may be operated by an operator located remotely from the jack hammer or pick tool. This enables the operator to be positioned away from the hot and often dangerous environment near the immediate vicinity of the furnace.
• the jack hammer or pick tool may be arranged so that it can be moved along a first axis that extends along the longitudinal axis of the jack hammer or pick tool so that the jack hammer or pick tool can move towards and away from the hole.
• the jack hammer or pick tool may also be arranged so that it can be moved in a lateral direction so that it can move horizontally relative to the hole. There may also a small amount of vertical movement as well, referred to as luff. It will be understood that arranging the jack hammer or pick tool to move in this fashion simplifies movement and mounting of the jack hammer or pick tool.
• the jack hammer or pick tool may also be arranged so that it can swivel horizontally relative to the hole (this movement is also referred to as yaw). There may also be a small amount of vertical swivel movement as well (this movement is also referred to as pitch).
• the hole that is drilled through the clay or mud has a diameter that is significantly smaller than the size of the tap opening in the furnace.
• the diameter of the tap hole drilled through the clay or mud may have a diameter that is less than 50% of the width of the tap opening in the furnace, even more suitably less than 40% of the width of the tap opening in the furnace, suitably less than 30% of the width of the tap opening in the furnace.
• the tap opening comprises a generally rectangular opening.
• other shaped tap openings may also be used.
• the tap opening may comprise a circular opening, an oval opening, a square opening, a triangular opening, or indeed any other shaped opening.
• the opening may have rounded corners.
• a tap hole is drilled through the clay or mud that packs the tap opening.
• the tap hole may be drilled using any known tap hole drilling equipment. There are numerous suppliers of such drill equipment and the person skilled in the art will readily understand how this drill equipment is constructed and operated. Therefore, it will not be necessary to describe the drill equipment further.
• an operator of the furnace can visually monitor the flow rate of slag from the furnace. If the operator determines that the flow rate of slag from the furnace is too low, the operator may then operate further equipment (such as a jack hammer or a pick tool) to remove further clay or mud from the periphery of the tap hole. This acts to enlarge the size of the tap hole, thereby allowing an increase in the flow rate of slag through the tap hole to take place.
• the size of the tap hole is enlarged by increasing a horizontal width of the tap hole. If the horizontal width of the tap hole is increased, the height of the tap hole in the furnace will remain essentially constant, which is important in ensuring that slag is removed through the tap hole rather than removing molten metal through the tap hole.
• the slag may be removed from the furnace in an essentially continuous manner.
• the tap opening has a height that is significantly larger than the diameter of the tap hole that is drilled through the clay or mud.
• the height of the tap hole can be adjusted by simply drilling the tap hole through the clay or mud at a higher level or a lower level, depending upon operational requirements.
• the present invention provides a top entrance submerged lance furnace comprising a furnace vessel lined with refractory material, characterised in that a side wall of the furnace vessel includes a generally rectangular tap opening.
• the generally rectangular tap opening has a width that is significantly larger than a diameter of a drill used to drill a tap hole through clay or mud that is packed into the tap opening.
• the tap opening may have a width that is from 2 to 10 times larger than the diameter of the drill, more suitably from 2 to 5 times larger than the diameter of the drill, even more suitably from 3 to 5 times larger than the diameter of the drill.
• the generally rectangular tap opening may have rounded corners.
• the generally rectangular tap opening may have a height that it is significantly larger than the diameter of the drill that is used to drill a tap hole through clay or mud packed into the tap opening.
• the tap opening may have a height that is from 2 to 15 times larger than the diameter of the drill, more suitably from 2 to 10 times larger than the diameter of the drill, even more suitably from 3 to 5 times larger than the diameter of the drill.
• the present invention provides a top entrance submerged lance furnace comprising a furnace vessel lined with refractory material, characterised in that a side wall of the furnace vessel includes a tap opening having a width substantially greater than a diameter of a hole drilled through mud or clay packed in the tap opening, the hole being used to remove slag from the furnace.
• the tap opening has a width that is significantly larger than a diameter of a drill used to drill a tap hole through clay or mud that is packed into the tap opening.
• the tap opening may have a width that is from 2 to 10 times larger than the diameter of the drill, more suitably from 2 to 6 times larger than the diameter of the drill, yet more suitably 2 to 5 times larger than the diameter of the drill, even more suitably from 3 to 5 times larger than the diameter of the drill.
• Figure 1 shows a side view of a top entrant submerged lance furnace vessel in accordance with an embodiment of the present invention
• FIG 2 shows a front view of a tapping block assembly used in the furnace vessel shown in figure l ;
• Figure 3 shows a cross sectional plan view of the tapping block assembly shown in figure 2 taken along section line A in Figure 2;
• Figure 4 shows a cross sectional side view of the tapping block assembly shown in figure 2 taken along section line B in Figure 2;
• Figure 5 shows a front view showing the positioning of a tap hole drill relative to the furnace vessel
• Figure 6 shows a front view showing the positioning of a jack hammer relative to the furnace vessel
• Figures 7 to 10 show various views of possible tap hole openings used in embodiments of the present invention. DETAILED DESCRIPTION OF THE DRAWINGS
• Figure 1 shows a side view of a top entrant submerged lance furnace in accordance with an embodiment of the present invention.
• the furnace shown in figure 1 may be an ISASMELTTM furnace. Such furnaces are stationary furnaces.
• the furnace 10 shown in figure 1 comprises an outer shell, generally referred to by reference numeral 14.
• the outer shell will typically be constructed from steel or a steel alloy.
• the outer shell will normally be lined with refractory material to protect the outer shell from the intense heat experienced inside the furnace during operation. . . .
• the furnace 10 has a side wall 16.
• the upper part 18 of the furnace includes an expanded region 20 that provides an outlet for gaseous products of the smelting reaction.
• a charge of feed materials is added.
• Fuel and air or oxygen are injected via a top entrant submerged lance. Smelting reactions then take place to form a molten metal or matte layer and a slag layer. Due to the extreme turbulence induced by injection of air or oxygen through the lance, the molten material in the furnace is vigorously agitated. As smelting continues, the amount of slag in the furnace will build up and it will become necessary to remove slag from the furnace.
• the furnace is provided with a tap opening 28 in a side wall thereof.
• Tap opening 28 is positioned in the sidewall at a height that is above the design height for the slag/metal or slag matte interface inside the furnace. In this manner, predominantly slag will be removed from the furnace via tap. Opening 28. Metal or matte is removed elsewhere from the furnace via a separate tapping operation.
• Figures 2, 3 and 4 showed further detail of the tap opening 28.
• the tap opening 28 is formed in a tapping block assembly 30, which includes a tapping block 44, made from water-cooled copper.
• the copper tapping block (44) is fastened to the furnace shell 48.
• the outermost face of tap opening 28 is protected by an outer plate 68.
• the actual shape of the opening formed in outer plate 68 is best shown in figure 2.
• the furnace is lined with layers of refractory material 64 and 32.
• the tapping hole passes through layers 64 and 32 also. Therefore, opening 28, 60 and 66 define an opening from the outside of the tapping block to the interior of the furnace.
• the tap opening 28 is a generally rectangular opening.
• the opening defined by respective opening 28, 60 and 66 is initially packed with clay or mud in order to seal the opening.
• clay or mud compositions that can be purchased for this purpose.
• clay or mud guns that can be used to apply or pack the clay or mud into the opening to close the opening. Therefore, it is not necessary to discuss these features any further.
• the tap opening 28 shown in figures 2, 3 and 4 has a width that it is substantially larger than the diameter of the tapping drill that is used to drill out the clay or mud that is used to pack and close the tap opening.
• the generally rectangular tap opening 28 may have a width that is about 2 to 6 times wider than the diameter of the tapping drill.
• Figure 5 shows a front schematic view of a tapping drill used to tap into the tap opening.
• the tap hole drill 80 is mounted to a secondary frame 82 that, in turn, is mounted to wheels 84, 86. Wheels 84, 86 enable the secondary frame 82 (and hence the tap hole drill 80) to move to the left or to the right.
• Further frame 88 may be considered to be a primary frame.
• Primary frame 88 has wheels 90, 92 mounted thereto. Wheels 90, 92 are mounted for rotation on rails 94, 96 so that the primary frame can move towards and away from the furnace.
• the tap hole drill 80 When it is desired to tap molten furnace products from the furnace, the tap hole drill 80 is moved so that the drill bit comes into alignment with the tap opening 28 (tap opening 28 is obscured by the drill in figure 5). The drill is activated and the bit is moved into contact with the clay or mud that packs the tap hole opening 28. Lateral adjustment of the position of the tap to the desired position is achieved by moving the secondary frame 82. The depth of the tap hole being drilled in " the tap opening is increased by moving the primary frame closer to the furnace as the drill operates. From the above description, it ' will be understood that the tap hole drill can move on both laterally and longitudinally. A launder 98 is positioned so that when the tap hole drill opens the tap hole, molten furnace products run out of the tap hole and down the launder 98.
• the tap hole opening 28 shown in Figures 1 to 4 has a width that is substantially wider than the diameter of the drill bit used to drill the tap hole into the clay or mud that packs the tap hole opening.
• a jack hammer or a pick tool may be used to increase the size of the tap hole.
• Figure 6 shows a jack hammer 1 10 that is mounted to a secondary frame 1 12- and a primary frame 1 14 in a manner that is similar to the mounting of secondary frame 82 and primary frame 88 shown in figure 5. This enables the jack hammer 1 10 to move both sideways (in a lateral direction) and longitudinally (in a direction towards and away from the furnace).
• Figures 7 to 10 show some possible variations in the shape of the tap hole formed in the tap ) opening.
• the tap opening 28 is shown.
• the tap opening is packed with mud or clay 120.
• a circular tap hole 122 has been freshly drilled in the clay or mud 120 using the tap hole drill.
• the circular tap hole 122 enables molten furnace products to flow out of the furnace. If the flow rate of molten furnace products out of the furnace through the generally circular tap hole 122 is not sufficiently large, the jack hammer 1 10 may be used to increase the size of. the opening.
• the generally circular taphole 122 may be widened by extending the sides 124, 126 by use of the jack hammer. This, of course, increases in the area of the opening, thereby enabling a higher flow rate of molten furnace products from the furnace. If the flow rate achieved through the opening shown in figure 8 is still not sufficiently large, the tap hole may be widened even further by further digging away the edges of the tap opening using the jack hammer. This is shown in figure 9, where the side edges 128, 130 of the tap opening have been even further widened, when compared to figure 8.
• the taphole 132 shown in figure 10 can be opened up again using the jack hammer to remove some of the solidified slag from the tap opening.
• the ability to selectively modify the size of the tap hole to vary the flow rate of molten furnace products (such as slag) through the tap hole is a feature that is believed to be unique to present invention. This feature is possible because the size of the tap opening is significantly larger than the size of the tap hole drilled through the clay or mud that packs the tap opening.
• Prior art tap openings were generally circular and had a diameter that was very similar to the diameter of the drill bit used to drill out the tap hole.
• prior art tap openings did not allow for the possibility of increasing the flow rate beyond the maximum flow rate provided by the size of tap hole formed by the drill bit.
• the tap hole once the tap hole has been drilled, there exists a significant extent of clay or mud between the wall of the tap hole and the sides of the tap opening. This allows removal of some of this clay or mud between the wall of the tap hole and the sides of the tap opening to thereby increase the size of the tap opening.
• the height or vertical extent of the tap opening is also significantly larger than the diameter of the drill bit used to drill out the tap hole. This enables the Vertical position of the tap hole to be varied so that the tap hole is always positioned correctly relative to the contents of the furnace. For example, if the tap hole is being used for slag tapping, the tap hole should be originally drilled through the clay or mud packing the tap opening at a height that it is above the interface between the slag layer and the metal layer.
• the present invention allows the flow rate of molten furnace products through the tap hole to be varied by controlling and modifying (as required) the size of the tap hole. Conventional tools can be used to implement the present invention.
• the invention provides greater control over the flow rate of molten furnace products through the tap opening. The flow rate can be controlled either automatically or by operator monitoring and intervention.
• the present invention is particularly suitable for use in operations where the liquid furnace product that is removed from the furnace is used as a feed material for a further downstream process.
• This 1 is desirable in that it allows for the possibility of being able to avoid intermediate storage vessels or to minimise the size required for any intermediate storage vessels that would otherwise be required to store the feed material for the downstream processing vessel in cases where the flow rate of that material from the top entrant submerged lance furnace is intermittent or of variable flow rate.
• the present invention minimises the footprint caster section of the furnace, and is ideal for retrofitting on existing furnaces, or implementation on new furnaces.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Furnace Charging Or Discharging (AREA)
• Vertical, Hearth, Or Arc Furnaces (AREA)
• Gasification And Melting Of Waste (AREA)
• Manufacture And Refinement Of Metals (AREA)
• Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)

Priority Applications (6)

Applications Claiming Priority (2)

Publications (1)

Family

ID=44059104

Family Applications (1)

Country Status (8)

Families Citing this family (6)

Citations (8)

Family Cites Families (8)

• 2010
  • 2010-11-09 JP JP2012539142A patent/JP5721734B2/ja active Active
  • 2010-11-09 PL PL399890A patent/PL218986B1/pl unknown
  • 2010-11-09 EA EA201290206A patent/EA022456B1/ru not_active IP Right Cessation
  • 2010-11-09 MX MX2012005700A patent/MX353976B/es active IP Right Grant
  • 2010-11-09 CN CN201080052439.9A patent/CN102686966B/zh active Active
  • 2010-11-09 AU AU2010321669A patent/AU2010321669B2/en active Active
  • 2010-11-09 BR BR112012011988-5A patent/BR112012011988B1/pt active IP Right Grant
  • 2010-11-09 WO PCT/AU2010/001491 patent/WO2011060483A1/en active Application Filing

Patent Citations (8)

Also Published As

Similar Documents

Legal Events