FI74302B - HUV FOER HOPSAMLING AV HETA GASER FRAON EN KONVERTER. - Google Patents

Description

1 74302

Hood for collecting hot gases from the converter Separated from application 813662

The present invention relates to a hood for collecting hot gases from an opening of a cylindrical longitudinally rotating body acting as a reaction vessel for a converter.

In the purification of many molten metals, it is customary to add substances, including air and gas blowing, to effect reactions that form reaction products with elements that are undesirable in the purified metal. Such reaction products are often physically separated from the desired purified molten metal, allowing these products and metal to be removed separately from the vessel in which the purification reactions have taken place.

For example, A.K. Biswas and W.G. In Extractive Metallurgy of Copper, 2nd Edition (1980), available from the Pergamon International Library, Davenport discusses in detail the conversion of copper rock to crude copper with a copper content of 98.5-99.5%. Molten copper rock can contain as little as 30-35% copper. It may also contain iron, sulfur, up to 3% dissolved oxygen, and minor amounts of various impurity metals present in the original ore concentrate but not removed during the smelting process.

This molten metal rock, which is charged at about 1100 ° C to the converter, is oxidized by air blowing to remove the above-mentioned impurities. The reactions following purification are exothermic and raise the temperature of the molten material.

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In the first slag-forming step, FeS. oxidizes to FeO 4, Fe 2 O 4 and SC 2 gas. The silica flux is added so that it combines with Feörho and a portion of? E-0, to form a liquid slag that floats on the surface of the molten metal rock and is poured off several times during this first step. Additional metal rock is added to the converter at regular intervals, followed by oxidation of much of the FeS contained in that charge and removal of slag.

When there is a sufficient amount of copper in the form of the primary melt in the converter and the primary melt contains less than 1% FeS, the final slag layer is poured off and the remaining impure copper is oxidized to crude copper.

Two types of converters have been used in the prior art. These are the Peirce-Smith converter and the Hoboken converter. Both have reaction vessels or bodies that are horizontally placed cylinders.

The Peirce-Smith converter is discussed on page 179 of the above-mentioned reference and includes an opening. The orifice is used to fill the converter, to remove large amounts of SO2 “carrier gas that develop during the blowing phase and which are collected by a loosely fitted hood above the body, and to cast molten metal from the converter. For casting purposes, the vessel is mounted on moving wheels so that it can rotate about its longitudinal axis until the opening is below the level of the molten metal so that the metal can drain out. The Hoboken converter is shown on page 198 of the above-mentioned publication and includes an orifice for filling and emptying and a separate opening at the right end for exhaust gases. This opening is located in the direction of the axis of the converter, and between it and the molten metal there is a dam structure shown as a goose neck in the drawing on page 198.

When using a Peirce-Smith converter, it is difficult to achieve good sealing in a single opening due to metal casting from the opening when the converter is emptied. This metal forms a deposit of 3 74302 and otherwise deteriorates the opening, so that it is difficult to ensure that the dome for the exhaust gases seals properly against the opening. Good sealing is desirable to prevent the removal of toxic gases and the dilution of the SC 2 component with air, which is not desirable when SO 2 is used to produce sulfuric acid in an additional process.

The problem with the Peirce-Smith converter has somehow been fixed in the Hoboken converter. The gooseneck is located separately so that only gases can flow over the dam out of the outlet. However, this is a rather complicated, expensive structure, and during the rotation of the converter, the liquid metal can get into the outlet and weaken it and the associated structures. In addition, the use of a dam reduces the volume of the reaction vessel.

The present invention relates to a dome of a converter for cleaning liquid metal. The converter has a substantially cylindrical horizontal, hollow reaction vessel rotating on its horizontal axis. The first opening of the vessel is used to charge the molten substance to be cleaned in the vessel.

The second opening is used to remove hot gases formed in the cleaning process, usually as a result of air blowing applied to the molten material. The second orifice is offset longitudinally and circumferentially from the first orifice, the circumferential displacement being sufficient to prevent liquid metal from leaking from the second orifice when the vessel is rotated from the first position where the substance is fed to the first orifice to the second position. The hood, which is in circumferential and longitudinal contact with the converter body, covers a surface area of the body sufficient to allow the collection of hot exhaust gases when the converter is rotated from the first position to the second position.

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The converter has converter means for cooling the exterior of the hull of the second opening region. An air-cooled jacket surrounds the converter body in this circumferential direction in this area. Cool air is blown into the open circumferential end of this sheath, and air is allowed to escape from the opposite open end. The tube, which is located in the circumferential direction separately from the body and has an opening directed towards the open end of the jacket, supplies cold air. When this jacket is used, the radial extension of the second opening extends into the valve with a hole through which the exhaust gases can escape. The hood should be located on top of the jacket rather than on top of the converter.

The hood has means for providing relatively good contact with the vigilance. The seal is located at the point where the dome in the circumferential or longitudinal direction contacts the sheath.

The invention is characterized in that the dome comprises a) circumferential sealing means along the edges of the dome in circumferential and frictional contact with the body, b) longitudinal sealing means in longitudinal contact with the edges of the dome of the dome to a body comprising (1) a hinged metal plate, in axial contact with the cylindrical body (iii) a rotating rod arranged along the dome parallel to the longitudinal axis of the cylindrical body with a metal plate attached to the rod and (iv) means for rotatably pressing the curved, convex edge of the metal plate against the body, the means comprising passing through the side wall of the dome, c) means for pivoting the longitudinal sealing means out of contact with the body when the material deposit on the body moves below the longitudinal seal, allowing the body to rotate about said longitudinal axis, and d) a gas seal rod and dome structure between tea.

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The longitudinal seal consists of a metal plate with a convexly curved edge located on top of the jacket. This plate, which is attached to a rod that can rotate, is bent against the sheath. When a substance precipitates on the jacket and the precipitate area rotates below the line where the slab touches the jacket, the slab momentarily moves away from the jacket until the area containing the precipitated substance has wound off the slab.

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Cooling of the hood is achieved by means of a network of pipes through which water is circulated through the outer walls of the hood. The hood is operated at a slightly negative pressure relative to the atmosphere, which prevents the removal of toxic gases from the first opening. This pressure is set low enough to prevent atmospheric gases from being sucked into the converter through the first orifice, which prevents dilution of the exhaust gases.

Other features and advantages of the invention will become readily apparent from the following description and the accompanying drawings, in which Figure 1 is a side cross-sectional view of a device according to the invention showing a converter vessel and dome; Figure 2 is a cross-sectional view taken along line 2-2 of Figure 1; cross-section taken along line 3-3, Fig. 4 is an enlarged side view of the device taken along line 4-4 of Fig. 1, Fig. 4A is an enlarged cross-sectional view of the terminal structure of Fig. 4, Fig. 5 is a detailed, more detailed and enlarged side view of the dome from the opposite direction of the viewing direction of Fig. 1, Fig. 6 is an enlarged cross-sectional view taken along line 6-6 of Fig. 4 showing details of the dome and circumferential seal structure; Fig. 7 is a cross-sectional view taken along line 7-7 of Fig. 6; a cross-sectional view taken along line 8-8 of Figure 7.

Figure 1 shows a side view of the device of the invention. The apparatus comprises a substantially cylindrical, hollow reaction vessel 1 formed of a steel shell 2 and lined with refractory brick and of a type known in the art. The reaction vessel is approximately 14 m long in this preferred embodiment and has an external odor of about 4.3 m, but it will be appreciated that other dimensions may be used depending on the amount of material to be purified.

The container 1 is supported at one end on a support ring 4, which is essentially a bearing. This bearing must be able to support the weight of the vessel 1 and at the same time withstand high operating temperatures outside the steel shell 2. It must also allow the end of the vessel 1 to move longitudinally for a short distance due to the thermal expansion and contraction of the vessel 1 as its temperature rises from ambient levels to the level of molten metal charged into the vessel and returns to ambient levels. Such a change in length is typically about 3.8 cm.

The opposite end of the vessel 1 is similarly supported, but no expansion is received at this end. In addition, this end is associated with a means for rotating the container 1. Typically, a gear-driven ring 5 is used. A gear (not shown), usually of small diameter and driven by a suitable motor, is toothed on the teeth associated with the ring 5. Such drive mechanisms are known in the art.

Liquid metal or cleaning agents are charged into the container 1 through the opening 6. For example, molten copper rock is charged with suitable buckets. A suitably positioned chute can be used to feed solids such as fluxes. The area of the opening 6 can be approximately 2.5 m. The outer surface of the shell 2 surrounding the opening 6 is reinforced with a metal plate 7. The ferrous metal structure forms a casting spout 8 which facilitates the pouring of molten material such as slag or purified metal from the vessel 1. The structure of the spout 8 is better seen in Figure 2.

There is a source of blowing gas, typically air, but possibly oxygen to facilitate purification of contaminants by oxidation 8 74302. The gas is introduced into the vessel through a pipe 9 which is connected to the radial extension 10 of the collecting pipe 10A by means of a ball joint 12 located on the axis of rotation of the vessel 1 and therefore allows the extension 10 to rotate with the vessel 1. A series of blowpipes or flues A, B, etc., emerge from the manifold housing 10A, forming an air path to be sprayed into the vessel 1 below the surface of the molten metal contained in the vessel. In a preferred embodiment, approximately 55 chimneys with a diameter of 5.08 cm are used. The amount of blowing gas required can be easily calculated by a person skilled in the art. It is clear that a smaller or larger amount of flue can be used as required. The vessel has a series of mechanisms 12A, 12B, etc., one for each flue, with a metal piston that can fit the flues. The mechanism causes these pistons to pierce the solid accumulated in the flues, which prevents the blowing gas from flowing back into the vessel.

In this embodiment, there is an outlet opening 13 through which the gas generated by the cleaning process can escape and has a surface area of 2.34 m. This opening is located at a point which is displaced longitudinally and circumferentially with respect to the opening 6, as can be seen from Figures 2 and 3. This circumferential displacement of the center line of the openings 6 and 13 is chosen so that the opening 13 remains under the hood 14 in circumferential and longitudinal contact with the container 1 over an area sufficient to cover the opening 13, hot, toxic but often industrially usable opening 13. to collect the exhaust gases in any operating position into which the vessel 1 can be rotated. The circumferential displacement is also sufficient to prevent liquid metal from leaking from the opening 13 when the container 1 is rotated from the first position to feed substances to the opening 6 to the second position to pour the contents of the container from the opening 6. The position shown in Figures 2 and 3 is the filling position. The vessel can be rotated counterclockwise by about 90 ° to pour the material from the feed cam 8, which is made into a 9 74302 half-cone to facilitate the casting step. In the latter position, the opening 13 remains under the hood 14.

Although the dome 14 may rest on the container 1 in some embodiments, the preferred structure comprises an air-cooled jacket 15 attached to and surrounding the container 1 to lower the temperature to which the dome 14 seals are exposed and prevent metal shell deterioration in the opening 13 by prolonged exposure to high temperatures. As shown in Figure 3, the radial extension 16 of the opening 13 extends into the jacket 15. The jacket 15 has an opening aligned with the inner diameter of the extension 16 and the intersection of the jacket 15 so that exhaust gases can exit to the dome 14 in circumferential contact with the jacket 15. and in longitudinal contact with the sheath 15 with the end seals shown in Figure 4 and explained below.

The tube 18 of Figure 1 conducts cool air to a tube 19 which is located in the circumferential direction slightly apart from the vessel 1 to allow the vessel 1 to rotate. The tube 19, which is substantially rectangular in cross-section and extends approximately 180 degrees around the vessel 1, but possibly extends completely around it, has an opening only in its radial wall next to the jacket 15. The sheath 15 has open circumferential ends, as best shown in Figure 3. Thus, air moves from the tube 19 through this opening (not shown) in its radially located wall to the region 20 between the vessel 1 and the sheath 15. This air simply flows through the region 20 leaving the end of the sheath 15 opposite the end adjacent to the tube 19. The purpose of the supports 17, 17A and 17C is to position the jacket 15 in the circumferential direction with respect to the container 1. If necessary, more subsidies can be used.

Figure 2 shows the loading or bath level 21 of the converter with respect to the center line 22 of the converter. Although Fig. 2 74302 10 shows the line 21 below the center line 22, the converter can be charged up to the center line 22 if the opening 6 is located in the correct position. The slag formed during the blasting step floats on the molten rock and can rise to a level about 15.24 cm above line 22. Although the converter can be used at slightly lower levels, maximum efficiency is usually achieved at maximum input. The nozzle 8 used in the casting is preferably formed by an angled cylinder. The figure shows a typical flue Z connected to the manifold 10A and pierced by a metal rod associated with the mechanism 12A as needed. Such mechanisms are known in the art.

In Figures 4, 4A and 5, the dome 14 is shown in more detail. The circumferential seal 24, which is one of the two seals sealing the housing 15 of the dome 14, will be explained in more detail below with reference to Figure 6. Tightening means 25 and 25A which tension the seals against the housing 15. will be explained in more detail with reference to Figures 7 and 8.

The end sealing plates 26 and 26A shown in Figs. 4, 4A and 5 are metal plates having curved ends 27 and 27A, respectively. The outer ends of the plates 26 and 26A are connected to rods 29 and 29A, which are hollow but could also be closed. These rods rotate with the slings in the wall of the sealing covers 30 and 30A associated with the dome 14. The extensions 91 and 91A of the rods 29 and 29A have means such as a spring or, preferably, counterweights 90 and 90A for bending the curved convex regions 28 and 28A of the plates 26 and 26A in contact with the sheath 15. The second seals 31 and 31A form a seal between the sealing rods 29 and 29A and the sealing supports 32 and 32A of the sealing covers 30 and 30A.

As the vessel ‘1 rotates, the end sealing plates 26 and 26A are located on the surface of the jacket 15. If there is a substance on the surface of the sheath 15 that forms a protrusion of its surface, the sealing plates 26 and 26A are forced to rotate away from longitudinal contact with the sheath 15 until the substance has passed the areas 28 and 28A. This degrades the efficiency of the seal, allowing some atmospheric gases to enter the dome, but usually this only takes a moment.

The walls of Figure 14 are cooled by water circulating through a network of pipes represented by pipes 45 on the outer surface of the dome. Cooling water can be derived from any suitable source, but it is clear that its temperature can rise to a point where high pressures are required to keep the water liquid. For example, water having a temperature of about 250 ° C and a pressure of 6, S95 MPa can be used. The cooling pipes must then be made of suitable materials and by suitable methods known in the art. Suitable connection means to the coolant source, such as the supply pipe 11, are used.

The baffles 100 and 100A deflect particulate material to the side to prevent accumulation of material on the end sealing plates 26 and 26A and associated structures.

During the cleaning process, the dome 14 is operated at a slightly negative pressure, typically 6.35 cm of water relative to the atmosphere. This low suction, provided by a speed-controlled suction fan known in the art, prevents hot toxic gas from escaping from the opening 6 if left uncovered, which is generally necessary to monitor the progress of cleaning and to pour off the slag formed in repeated loading and cleaning agents. In general, it is not desirable to suck air into port 6. This is prevented by keeping the suction pressure low, as noted. The purpose of this is to prevent the dilution of hot exhaust gases which, in the cleaning of copper, contain large amounts of sulfur dioxide and which can be used for the production of sulfuric acid 1 2 74302 in another plant. This plant can provide the small suction needed to reduce the pressure in the hood.

The dome 14 is preferably supported by a suitable structure slightly above the container 1. This ensures that the thermal expansion and contraction of the dome structure does not adversely affect the efficiency of the circumferential seals. The hot exhaust gases are preferably cooled by means of a heat exchanger. Waste heat can be recovered for use elsewhere and the gases can be cooled to a temperature suitable for further chemical treatment.

Figure 6 is a cross-sectional view of a particular area of the dome illustrating the structure of a single circumferential seal 24. The sealant 35, which is a flexible, braided material having a rectangular cross-section and containing refractory asbestos and graphite components, is forced into contact with a smooth raised surface of a substantially rectangular protrusion 36 arranged around the circumference of the sheath 15. The sealant 35 is housed in a housing 37 consisting of portions 38 and 39 and is curved along the circumference of the sheath 15 and fixed at regular intervals to a flange 40 connected to a curved extension of the wall 41 of the dome 14. The bolt 42 and nut 43, which are typically used (as shown in Figure 7), secure the portions 38 and 39 to the flange 40. A seal 44, which is a suitable refractory material, which may be similar to the sealant 35, is located between the portion 39 and the flange 40. As mentioned above, the pipe 45 through which the water circulates cools the wall 41 and its circular extension.

In the housing 37 there is a retaining strip 46 to which the side opposite the protrusion 36 of the sealing material 35 is attached. The housing 37 also has a tensioning strap held radially outwardly from the retaining strap 46 by a plurality of spring brackets, one of which is shown as a spring bracket 48. The strap 47 is used when tightened by tensioning means 25 (shown in Figure 4 and explained in more detail below in Figure 7 below). ), to bend the sealant 13 74302 against the protrusion 36.

Figure 7 is a cross-sectional view taken along line 7-7 of Figure 6 of V-shaped spring brackets, only one of which is shown in Figure 6. Although a variety of compression spring members could be used between the strips 46 and 47, these spring brackets are particularly suitable. The tip 50 of each bracket is welded to the tension strip, leaving the curved ends 50A and 50B of the V free to move slightly relative to the strip 46 as the strip 47 is tightened by the tensioning means 25, as shown in detail in Figure 7.

Each end of the strip 47 is firmly attached to the slot of the elongate member 51. This member has a non-circular, preferably square, cross-section K in the area where it passes through a uniform, tightly fitting hole in the end plate 52, as best shown in Figure 8. A spring 53 is placed on the member 51 between the holders 54 and 55. The portion of the member 51 comprising the end 56 of the member 51 not connected to the strip 47 is circular and threaded in cross section. The nut 57 moves in this thread resting on the detent 55 as it is rotated in a direction that causes it to approach the end plate 52, tightening the belt 47 under compression of the spring 53, which can be 1.27 cm from the uncompressed space, typically 227 kg. As shown in Figure 4, there are two tightening means, one at each end of the circumferential sealing structure 24. In practice, the nut 57 associated with each tightening means can be tightened to provide similar compression of the springs.

The bolt 59 and nut 60 of Figure 7 are one of three pairs of fasteners, with Figure 8 showing bolts 59, 62 and 63 for securing the end plate 52 to a flange 61 connected to the housing portions 38 and 39. As also shown in Figure 8, the end sealing plate 26A is in contact with the sheath 15.

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It should be noted that the sealant 35 is generally flexible and deforms if a precipitate were to appear on the protrusion of the jacket 15 as the jacket 15 rotates relative to the sealing structure of the dome 14. Thus, in contrast to end sealing plates, relatively good sealing can be maintained here despite the formation of small deposits between the material 35 and the protrusion 36. However, even small precipitates are unlikely because substance 35 covers the area of action of the protrusion when it may be exposed to hot exhaust gases, which may contain particles of matter that precipitate on exposed surfaces.

Various modifications of the invention in addition to those shown and described herein will be apparent to those skilled in the art from the foregoing description and the accompanying drawings.

Claims (12)

1. A cap (14) for collecting hot gases from the opening (13) of a cylindrical body (1) rotating about its longitudinal axis, characterized in that it comprises a) a ring sealing member (24), along the edges of the cap (14) in circumferential and b) a longitudinal sealing member along the edges of the cap in longitudinal contact with the body (1), comprising (i) a threaded metal plate (26; 26A) (ii) a curved, curved edge ( 28; 28A) which is in axial contact with the cylindrical body (iii) a rotating rod (29; 29A) arranged along the shaft in the direction of the longitudinal axis of the cylindrical body, a metal plate (26; 26A) being attached to the rod (29; 29A) and (iv) a means for pressing the curved, curved edge (28; 28A) of the metal plate (26; 26A) rotating against the body, which means includes a counterweight (90, 90A) on an extension of the rod (91; 91A) c) means for pivoting the longitudinal sealing member away from its contact with the body (1), whereby the material deposited on the body moves under the longitudinal seal, allowing a rotation of the body around said longitudinal axis, and d) a gas seal (30, 30A) between the rod and the casing structure. The hood according to claim 1, characterized in that it comprises a cooling means. Cutter according to claim 2, characterized in that the cooling means comprises a pipe network (11, 45) through which the water is circulated, the pipes (45) being located on the outer walls of the hood. 4. A clamp according to claim 1 or 2, characterized in that the ring sealing means (24) comprises a) a flexible refractory material (35) and b) a means for bending said material (35) in peripheral contact with the body. The cap according to claim 4, characterized in that the bending means comprises a) a capsule (37) in which said material (35) is placed and which extends along the edge of the cap, b) an opening in capsule through which said material (35) extends (c) a cap band (46) in capsein which is attached to the surface of said material (35) which is opposite to the body; (d) a tension band (47) located in the cover and extending (e) a plurality of compression spring members (48) between the pouring belt (46) and the clamping belt (47); and (f) a member coupled to the jacket intended to clamp the strap, the compression spring members (48) bending said material (35) against the body. The cap according to claim 5, characterized in that the means which tension the strap comprises a) an elongated member (51), to which the strap (47) is fixed and provided with a round, threaded part (56), b ) a fixed heeled plate (52) through which the elongate member (51) extends; c) a coil spring (53) arranged around the round threaded portion of the elongate member (51), one of which star in contact with said plate (52, 54), d) a stop means (55) arranged at the end of the coil spring (53) opposite said fixed plate (52), e) a nut which rotates pS the threaded portion (56) of the elongate member and rests against the stop member (55) and compresses the coil spring (53), exposing the tension band (47) to tension. 2i 74302 The cap according to claim 1, characterized in that the ring seal means comprises a) a strap (35) a. flexible refractory material and b) a means for bending said material (35) in peripheral and frictional contact with the body, the bending member comprising (i) a capsule (37) in which said material (35) is positioned and extending along the edge of the cap, (ii) an opening in said capsule (37) through which said material (35) extends radially inwardly toward the body, (iii) a capsule pouring band attached to the surface of said material (35), (iv) a clamping band (47) arranged in the jacket and extending radially outwardly from the body (v) a plurality of compression spring members (48) arranged between the hall band (46) and the clamping band (47) and (vi) a means for tensioning the strap, the compression spring part (48) bending the sealing material (35) against the body. The cap according to claim 7, characterized in that the tensioning member of the strap comprises a) an elongate member (51) to which the strap (47) is attached, b) a fixed, heeled plate (52) through which the elongate member extends , c) a coil spring (53) arranged around the elongate member (51), one end thereof in contact with said plate (52, 54), d) a stop member (55) disposed at the end of the coil spring. (53) located opposite said plate (52), e) a round, threaded portion (56) of the elongate member (51) extending into the coil spring (53) and f) a nut (57), which rotates on said threaded portion (56) and rests on the stop member (55) and compresses the coil spring (53), whereby tension is exerted on the clamping band (47). 22 74302 The cap according to claim 8, characterized in that the shark of the fixed plate (52) has a non-circular cross-section and closely surrounds the elongate member (51) having the same cross-section as said shark where it penetrates the plate, the elongate member (51). ) is prevented from rotating as the nut (57) is turned. The cap according to claim 9, characterized in that the compression spring members (48) comprise substantially V-shaped spring shackles, the tips of the shackles (50) staring in contact with the strap (47) and the heads of the shackles (50A and 50B) staring in contact with the pouring tape (46). The cap according to claim 1, characterized in that the ring sealing means comprises a) a belt of flexible, refractory material (35) and b) a means intended to bend said material (35) in peripheral and frictional contact with the body, the gauge comprises (i) a capsule (37) in which said material (35) is disposed and extending along the edge of the cap, (ii) a clamping band (47) which is provided in the jacket and extends radially leaking from the the body and (iii) a means for tensioning the strap. The cap according to claim 11, characterized in that the tensioning member of the strap comprises a) an elongated member (51) which is attached to the strap (47) and has a round, threaded part (56), b) a fixed, heeled plate (52) through which the elongate member (51) extends; c) a coil spring (53) arranged around the round threaded portion of the elongate member, one end thereof in contact with said plate (52, 54)