RU2176060C2 - Unit for metal smelting from oxide-containing ores - Google Patents

Abstract

FIELD: metallurgy. SUBSTANCE: unit has two melting chambers arranged in cascades. The second chamber is located below the first one. Means for supply of slag melt for smelting to the second chamber is made in the form of slag pipeline with two vertical sections ensuring withdrawal of slag from the first chamber by one vertical section and supply of slag melt to the second chamber by the other vertical section. There is a member for connection with means for producing rarefaction in unit. Means for supply of melt slag for smelting is installed in catching mechanism of device of its reciprocation and turning relative to vertical axis. Means for withdrawal of slag from the second chamber is made in the form of slag pipeline with at least one vertical section and member for connection with device for rarefying it. Means for withdrawal of slag is installed for reciprocation along axis of the second chamber to point of maximum concentration of slag. EFFECT: provision of conditions for accelerated and differential reduction of metals form their oxides, usefully realized centrifugal effect and effect of countercurrent of slag and metal during their rotation by magnetic hydrodynamic device; protection of lining of unit melting chambers from aggressive attack of slag. 2 cl, 2 dwg

Description

 Complexes are widely known in the iron and steel industry, including equipment for the production of intermediate products, for example cast iron, in a blast furnace, and equipment for the production of a product, for example steel, from cast iron in a converter. To transfer the intermediate to the next stage of processing, it is necessary to use expensive cast-iron equipment and equipment for storing liquid cast iron (mixers).

 Complexes are also widely known in non-ferrous metallurgy, including equipment for the production of an intermediate product, for example matte, from oxidized nickel ore in a shaft furnace and equipment for the production of a product, for example matte, from matte in a converter [1, p. 276-286]. Complexes for smelting the intermediate product and the product are located remotely from each other, and for transporting the intermediate product to the next processing stage it is necessary to use expensive equipment, such as special ladles and bridge cranes, and other equipment.

 Known complexes for smelting cast iron and its cleaning from non-metallic inclusions (from slag), including a magnetodynamic device (MHD device) [2, p. 194, Fig. 92], which allows cast iron to rotate due to the rotating electromagnetic field and due to the emerging centrifugal forces to concentrate non-metallic inclusions in the center of the paraboloid hole. Non-metallic inclusions from the place of concentration are removed through a slag outlet located in the bottom (ceramic pipe). The working conditions of the slag outlet are very difficult. Its replacement is laborious and requires a long shutdown of the complex for cleaning cast iron.

 A technical solution is known when non-metallic inclusions are removed from steel before casting steel at the continuous casting machine due to the rotation of the steel by the MHD device / 3 /. The disadvantage is the difficulty in removing the resulting slag.

 A known technological solution for the processing of sulfide copper ore into blister copper / 4, p. 375-413 /, in which the unit adopted for the prototype is implemented, including at least two melting chambers of the melting device, means for supplying melting to the first chamber of the solid charge and melt into the second chamber, means for introducing energy for melting, means for cleaning metal products of melting, means slag and gas removal means.

 The disadvantage of the prototype is that the transfer of the melt from the chamber where the solid charge is melted to the chamber where this melt undergoes further processing, as well as the removal of slag from the second chamber, is carried out by gravity and is poorly controlled. There are no devices in the chambers of the unit that would beneficially act on the melting processes in these chambers and would help to efficiently discharge both the melt from the first chamber to the second and the slag from the second chamber.

 The novelty of the proposed technical solution lies in the fact that two melting chambers are placed in cascade, with the second chamber being lower than the first, the means for supplying slag melt for melting into the second chamber is made in the form of a slag pipeline with two vertical sections and an element for connecting to a rarefaction means in it and installed in the gripping mechanism of the device for its reciprocating movement and rotation relative to the vertical axis. The slag pipeline provides the removal of slag from the first chamber in one vertical section and the flow of slag melt into the second chamber with the other, and the slag removal means from the second chamber is made in the form of a slag pipeline with at least one vertical section and an element for connecting to the rarefaction means in it and installed with the possibility of reciprocating movement along the axis of the second chamber to the place of maximum concentration of slag. Around the round cases of the melting chambers there are magneto-hydrodynamic devices with a rotating electromagnetic field.

 This technical solution allows you to effectively solve the problem of taking the melt from the first processing chamber in the second chamber and the problem of slag removal from the second chamber. The use of MHD devices on the first and second chambers allows, firstly, to efficiently carry out melt collection and slag removal operations and, secondly, to use separate technological methods that allow the accelerated reduction of metals from oxides at the slag-metal interface and it is useful to use centrifugal effect in the liquid phase reduction of metals from oxides.

 In FIG. 1 shows a diagram of the unit at the time of feeding the solid charge into the first chamber of the unit and processing the melt in the second chamber of the unit, FIG. 2 shows a diagram of the unit at the moment when the slag pipeline is moved to the lower position and the end face of the first vertical section of the slag pipeline is maximally immersed in the slag of the first chamber and the slag pipeline is ready for overflowing slag from the first chamber to the second.

 The unit includes two structurally identical chambers 1 and 2 (Fig. 1). The purpose of the first chamber is the processing of the solid charge 3, the purpose of the second is the processing of the melt (slag) obtained after processing the solid charge in the first chamber.

 Chambers 1 and 2 are cascaded, so that after filling the slag pipe 4 in the means 5 for feeding slag from the chamber 1 to the chamber 2, this slag is then transferred by gravity.

Slag pipeline 4 contains two vertical sections, which are configured to be quickly inserted into chambers 1 and 2 through nozzles 6 and 7, overlapped by removable covers 8 and 9, and nozzle 6 is placed in the cover 10 of chamber 1 exactly in the center of the chamber. To move the slag conduit 4 up and down, the means 5 is equipped with a hydraulic actuator 11, the rod 12 of which is connected to the slag conduit 4 through a unit 13 in which a thrust bearing 14 is located, which contains a thrust bearing, which allows the slag conduit 4 to be rotated by an angle of at least 90 ^° after lifting it to the upper hydraulic actuator position 11.

 A device 15 is connected to the slag conduit 4 through which the slag conduit can be connected to a vacuum system in the slag conduit when the end of one vertical part of the slag conduit 4 is placed in the slag and when the end face of the second vertical part of the slag conduit 4 is placed in the pipe 7 covered by the burned shutter (Fig. 2).

 In the lid 10 (Fig. 1) there is a pipe 16, which is an element of a means of supplying a solid charge into the chamber 1, a pipe 17, which is an element of a means of exhausting gas, and a pipe 18, which is an element of a means of supplying energy to the melting.

 A pipe 7 is placed in the lid 19 of the chamber 2. In this center of the chamber there is a pipe 20 overlapped by a removable cover 21, with respect to which the vertical part of the slag pipe 22 of the slag removal means 23 from the chamber 2 can be placed. A device 24 is also connected to the slag pipe 22, through which the slag pipeline can be connected to a system for creating a vacuum in the slag pipeline, if necessary, remove slag from the chamber 2.

 The slag cleaning means 23 is also provided with a slag conduit drive up and down and a rotation drive (not shown). A nozzle 25, which is an element through which means for supplying energy to the melting, and a nozzle 26, which is an element of the means for removing gases from the chamber 2, are placed in the lid 19.

 MHD devices 27 and 28 are placed around the bodies of chambers 1 and 2 to ensure the rotation of metal and slag melts in chambers 1 and 2.

 In the bottom of the chambers, metal wires 31 and 32 are blocked by shutters 29 and 30 for draining the melts into ladles 33 and 34. In the lids of the chambers 10 and 19, sleeves 37 and 38 are blocked by covers 35 and 36 for placement in them and in the holes in the lining of the tubes, which bulk material is introduced into the metal wires 31 and 32 at the end of the cycle of draining the metal from the chambers and when the shutters 29 and 30 block the indicated metal wires from below.

 The operation of the unit is as follows.

 Before putting the unit into operation according to the technological instruction, the lining of the unit chambers is heated. Further, metal melts are pre-induced in the chambers, and it is desirable to have their chemical compositions as they would be for the produced melting products. The amount of induced melt in the chamber must correspond to the “swamp” that remains in the chamber after the newly produced metal is drained from it.

 Then, an MHD device is put into operation, with the help of which the metal of the “swamp” is untwisted until a hole of a parabolic shape of a given size is formed.

 During preliminary guidance of the “swamp” and during the melting of the charge, energy is introduced into the chambers, which, depending on the melted charge, can come from various burners (gas, fuel oil, fuel-oxygen, plasma), and also, if necessary, from channel induction units.

 After bringing the "swamp" into rotation in chamber 1 (Fig. 1), a pre-prepared solid charge, for example, oxidized nickel ore with appropriate additives, allowing the reduction of nickel and partially iron from oxides and to obtain slag of the corresponding chemical composition and melting temperature, is fed for processing suitable for processing in chamber 2.

 After the specified slag has accumulated in chamber 1, covers 8 and 9 are removed from nozzles 6 and 7 and the first vertical part of the slag pipeline 4 is introduced into chamber 1, and the second vertical part of the slag pipeline 4 is introduced into chamber 2. As soon as the end face of the first vertical part of the slag pipeline 4 is immersed in the slag in the center of the hole to a place close to the surface of the metal melt (see Fig. 2), the device 15 is actuated and a rarefaction is created in the slag conduit 4, which allows the melt for the second chamber 2 to be raised by the required value and then this melt will move along w akoprovodu 4 to the end face of the second vertical portion, which at this time shall be stopped burnable damper. The damper burns in a matter of seconds and from that moment slag (melt for chamber 2) will begin to flow onto the surface of the metal melt previously brought into rotation in chamber 2. Since the cameras are cascaded, and the chamber 2 is lower than the chamber 1, conditions are created for feeding the melt from the chamber 1 to the chamber 2 by gravity. When performing the operation of pumping slag melt from chamber 1 to chamber 2, the supply of solid charge and energy to chamber 1 is stopped, but as soon as the supply of slag melt to chamber 2 is stopped, the supply of solid charge and energy to the first chamber is resumed.

 It should be noted, however, that during the termination of the supply of solid charge and energy to chamber 2, this chamber can be sealed and then gas pressure can be increased in it by introducing, for example, inert gas into the chamber. In this case, it is not necessary to create a vacuum in the slag pipe 4 and have a burnable damper at the end of the second vertical section of the slag pipe 4.

 The metal melt from the chamber 1 (Fig. 1) will most often be discharged into the ladle 33 through the metal wire 31 after several slag removal from the chamber 1 into the chamber 2. Before the removal of metal from the chamber 1, the shutter 29 moves, the bulk refractory material from the metal wire 31 is poured and a metal plug is burned through the tube with oxygen, which is formed in the metal wire 31 above the refractory bulk material. After the cessation of the discharge of metal from chamber 1, metal remains in it equal to the mass of the “swamp”.

 It should be noted that if the slag melt from the chamber 1 can be removed without stopping the rotation of the metal melt, then the removal of metal from the chamber 1 should be carried out after the termination of the rotation of the metal in the chamber, but if this removal is not accompanied by the abandonment of a “swamp”, then the metal is removed from chambers should be carried out during metal rotation. Then in the chamber on the bottom there will be almost no liquid metal.

 From the chambers, the metal merges through a horizontal channel and a vertical metal wire in the bottom. Placing a horizontal channel in the chamber wall determines the mass of the “swamp”.

 After the receipt of the slag melt through the slag conduit 4 into the chamber 2, it begins to be processed under the conditions of rotation of the metal and slag melts in the chamber 2 with the introduction of the necessary additives, for example, the corresponding reducing agent. The introduction of the reducing agent and additives is carried out through the pipe 20 after the second vertical part of the slag pipe 4 is removed from it or through a specially made hole in the cover 19 (not shown).

 If oxidized nickel ore is fed to the remelting chamber 1 and ferronickel is the marketable product of this chamber, then after processing the slag melt of chamber 1 in chamber 2 in this chamber, the marketable product may be cast iron or steel and slag suitable after introducing the necessary additives for production, for example cement.

 The removal of metal and slag from chamber 2 is carried out similarly to the removal of metal and slag from chamber 1.

The technical result that can be obtained by implementing the invention is as follows:
conditions are created in the unit for accelerated and differentiated recovery of metals from their oxides; accelerated recovery occurs because the contact area between the slag and the metal increases due to the formation of a paraboloid-shaped hole during the rotation of the metal and slag and because the centrifugal effect and the counterflow effect between the slag and the metal during their rotation are useful;
relatively high productivity is achieved with a small mass of equipment, since it becomes possible to concentrate relatively large energy in the melting chambers of the unit, since favorable conditions are created for the absorption of this energy, in particular, due to the effective mixing of the melts;
the lining of the melting chambers of the unit is protected from the aggressive effects of slag, as conditions are created that eliminate the contact of the lining with slag.

Sources of information
1. Zeidler A.A. Metallurgy of copper and nickel. M .: Metallurgizdat, 1958.391 s.

 2. Powkh I.L., Cabbage A.B., Chekin A.B. Magnetic hydrodynamics in metallurgy. M .: Metallurgy, 1974.239 s.

 3. Lopukhin G.A. Abstract in the journal "Iron and Steel News Abroad". 1997, N 1. S. 64-67.

 4. Khudyakov I.F., Klein S.E., Ageev N.G. Metallurgy of copper, nickel, related elements and design of workshops. M.: Metallurgy, 1993.432 s.

Claims (2)

 1. A unit for smelting metal from oxide-containing ores, containing at least two melting chambers, means for supplying for melting into the first chamber a solid charge and melt slag in the second chamber, means for introducing energy for melting, means for cleaning metal products of melting, means for removing slag from the second chamber and gas removal means, characterized in that the two melting chambers are cascaded, the second chamber being lower than the first, the means for supplying the slag melt for melting into the second chamber is made in the form of a slag pipeline with two vertical sections that ensure the removal of slag from the first chamber in one vertical section and the flow of slag melt into the second chamber with another, and with an element for connecting to the rarefaction means in it, and is installed in the gripping mechanism of the device for its reciprocating movement and rotation about the vertical axis, and means for cleaning slag from the second chamber is made in the form of a slag pipeline with at least one vertical section and an element for connecting to the means of creating a vacuum in it and installed but with the possibility of reciprocating movement along the axis of the second chamber to the point of maximum concentration of the slag.  2. The unit according to claim 1, characterized in that around the round bodies of the melting chambers there are magneto-hydrodynamic devices with a rotating electromagnetic field.

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