A device and method for increasing vanadium content in molten iron

Abstract

The application provides a device and method for increasing vanadium content in molten iron, the device comprising: a ring-shaped pipeline located along the upper side of a molten iron tank, the ring-shaped pipeline being arranged below a flow nozzle of a runner and aligned with the flow nozzle; a plurality of first exhaust holes located on the upper side of the ring-shaped pipeline, the first exhaust holes being used for spraying protective gas in the direction of the flow nozzle to form a longitudinal protective gas curtain for the flow of molten iron, wherein the oxygen content in the protective gas is lower than a first threshold value. The device and method for increasing vanadium content in molten iron provided by the application form a protective gas curtain for the flow of molten iron through the ring-shaped pipeline during the conveying of the molten iron to the molten iron tank, thereby reducing the contact between the molten iron and oxygen, reducing the oxidation loss of vanadium, and improving the yield.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of iron and steel metallurgy, and more particularly, to a device and method for increasing the vanadium content in molten iron. BACKGROUND

[0002] In the smelting of vanadium-titanium magnetite, the molten iron contains vanadium and titanium of high economic value. In the past, vanadium was extracted from the molten iron by atomization, and the current mainstream process is to extract vanadium by converter, which is more efficient. In order to improve the yield of vanadium, on the one hand, during the smelting of blast furnace, vanadium in the ore is as much as possible to enter the molten iron, such as increasing the furnace temperature and other measures; on the other hand, during the extraction of vanadium by converter, as much as possible vanadium is left in the semi-steel, and the residual vanadium content in the semi-steel is 0.02-0.025% according to the current advanced technology.

[0003] In view of the problem of retaining vanadium in molten iron, CN112981045A discloses a method for dephosphorization and vanadium retention of vanadium-containing phosphorus molten iron, mainly comprising the following steps: (1) introducing the desulfurized vanadium-containing and phosphorus-containing molten iron produced by blast furnace or non-blast furnace into an induction furnace; (2) adding dephosphorization slag and spraying CO2 according to the phosphorus content, which can be top blowing, bottom blowing, side blowing or top and bottom combined blowing; (3) when the phosphorus content in the vanadium-containing and phosphorus-containing molten iron is reduced to below 0.03%, stop spraying, and separate the slag from the molten iron. The method makes the vanadium loss rate in the molten iron less than 10%, achieving the effect of dephosphorization and vanadium retention.

[0004] However, during the tapping process, the molten iron is exposed to the air all the time when it flows from the iron notch to the molten iron tank, and the surface of the molten iron reacts with oxygen in the air, resulting in the loss of part of the vanadium. Especially during the process of the molten iron flowing through the iron channel nozzle and into the molten iron tank, the molten iron stream fully contacts with the molten iron, causing the vanadium in the molten iron to oxidize with oxygen in the air, reducing the vanadium in the molten iron. According to the on-site sampling analysis, the vanadium in the molten iron is lost by 0.008%-0.02% (under the condition of 0.3% vanadium content in the molten iron) during the process of the molten iron flowing through the nozzle and into the molten iron tank.

[0005] Based on this, the inventors of the present application realize that there is still room for further improvement in reducing the loss of vanadium content in the molten iron as much as possible during the process of delivering the molten iron to the molten iron tank. SUMMARY

[0006] This disclosure summarizes aspects of embodiments and should not be used to limit the claims. Other implementations can be contemplated based on the technology described herein, which will be apparent to those of ordinary skill in the art upon examining the following drawings and detailed description, and these implementations are intended to be included within the scope of the present application.

[0007] The inventors of this application recognize the need for an apparatus and method to increase the vanadium content in molten iron, which should be able to minimize the loss of vanadium content in the molten iron and increase the yield during the process of conveying the molten iron to the ladle.

[0008] According to one aspect of the present invention, an apparatus for increasing the vanadium content in molten iron is provided, comprising:

[0009] An annular pipe located above the edge of the molten iron ladle, the annular pipe being positioned below the spout of the trough and aligned with the spout;

[0010] A plurality of first vent holes are located on the upper side of the annular pipe. The first vent holes are used to spray protective gas toward the nozzle to form a longitudinal protective gas curtain for the molten iron flow.

[0011] The oxygen content in the protective gas is lower than a first threshold.

[0012] According to one embodiment of the present invention, a plurality of second vent holes are located on the outer side of the annular pipe, the second vent holes being used to spray protective gas in the direction of the outer periphery of the annular pipe to form a horizontal protective gas curtain for the molten iron flow.

[0013] According to one embodiment of the present invention, a plurality of third vent holes are located on the lower side of the annular pipe, the third vent holes being used to spray protective gas into the molten iron ladle to reduce the oxygen content inside the molten iron ladle.

[0014] According to one embodiment of the present invention, the protective gas includes combustion exhaust gas.

[0015] According to one embodiment of the present invention, the annular pipe is connected to the exhaust gas discharge pipe of the hot blast furnace.

[0016] According to one embodiment of the present invention, the diameter of the annular pipe is 3000-4000 mm.

[0017] According to one embodiment of the present invention, the diameter of the first vent hole is 2 to 5 times the diameter of the second vent hole.

[0018] According to one embodiment of the present invention, the diameter of the first vent hole is 10 mm and the diameter of the second vent hole is 4 mm.

[0019] According to one embodiment of the present invention, the angular spacing between adjacent second exhaust holes is 15-20 degrees.

[0020] According to one embodiment of the present invention, the annular pipe is located 5 to 10 cm above the rim of the molten iron ladle.

[0021] According to another aspect of the present invention, a method for increasing the vanadium content in molten iron is provided, comprising the following steps:

[0022] Molten iron containing vanadium is poured into the molten iron ladle through the spout of the iron trough;

[0023] Protective gases are ejected from the molten iron ladle in the direction of the spout and in the horizontal direction to form a longitudinal protective gas curtain and a horizontal protective gas curtain, respectively, wherein the oxygen content in the protective gas is lower than a first threshold.

[0024] The apparatus and method for increasing the vanadium content in molten iron proposed in this invention form a protective gas curtain for the molten iron flow through an annular pipe during the process of transporting molten iron to the molten iron ladle. This reduces the contact between the molten iron and oxygen, thereby reducing the oxidation loss of vanadium and increasing the yield. Attached Figure Description

[0025] To better understand the present invention, reference can be made to the embodiments shown in the following figures. Components in the figures are not necessarily drawn to scale, and related elements may be omitted, or in some cases the scale may have been enlarged to emphasize and clearly illustrate the novel features described herein. Additionally, as is known in the art, system components may be arranged differently. Furthermore, in the figures, the same reference numerals denote corresponding parts throughout several views.

[0026] Figure 1 A schematic diagram of the operation of an apparatus for increasing the vanadium content in molten iron according to an embodiment of the present invention is shown.

[0027] Figure 2 A perspective view of an apparatus for increasing the vanadium content in molten iron according to an embodiment of the present invention is shown;

[0028] Figure 3 A top view of an apparatus for increasing the vanadium content in molten iron according to an embodiment of the present invention is shown;

[0029] Figure 4 A side view of an apparatus for increasing the vanadium content in molten iron according to an embodiment of the present invention is shown.

[0030] List of reference numerals in the attached diagram:

[0031] 100, Device for increasing the vanadium content in molten iron; 102, Annular pipe; 104, First vent; 106, Second vent; 108, Molten iron ladle; 110, Molten iron trough; 112, Spout; 114, Molten iron flow; 116, Longitudinal protective air curtain; 118, Horizontal protective air curtain; 120, Air source; 122, Air pipe; 124, Air inlet. Detailed Implementation

[0032] The following describes embodiments of the present disclosure. However, it should be understood that the disclosed embodiments are merely examples, and other embodiments may take various alternative forms. The drawings are not necessarily drawn to scale; certain functions may be exaggerated or minimized to show details of particular components. Therefore, the specific structural and functional details disclosed herein should not be construed as limiting, but merely as a representative basis for teaching those skilled in the art to use the invention in various ways. As will be understood by those skilled in the art, various features shown and described with reference to any of the drawings may be combined with features shown in one or more other drawings to produce embodiments not explicitly shown or described. The combinations of features shown provide representative embodiments for typical applications. However, various combinations and modifications of features consistent with the teachings of this disclosure may be desirable for certain particular applications or implementations.

[0033] In this application, when an element or part is referred to as "on," "joined to," "connected to," or "coupled to" another element or part, that element or part may be directly joined, connected to, or coupled to the other element or part, or there may be an element or part intervening therebetween. Conversely, when an element is referred to as "directly on," "directly joined to," "directly connected to," or "directly coupled to" another element or part, there may be no element or part intervening therebetween. Other terms used to describe the relationship between elements should be interpreted in a similar manner.

[0034] As mentioned in the background section above, the inventors recognized that there is still room for improvement in the prior art regarding minimizing vanadium loss in molten iron. A solution is needed that can minimize vanadium loss in molten iron and increase yield during the transfer of molten iron to the ladle. Based on these problems and room for improvement in the prior art, the inventors of this application provide an apparatus and method for increasing the vanadium content in molten iron in one or more embodiments, which are believed to solve one or more problems in the prior art.

[0035] The inventors of this application discovered that during the process of vanadium-containing molten iron flowing from the trough to the ladle, the height difference between the spout and the upper edge of the ladle is 2-5m, and the time to fill a ladle with molten iron is 25-60 minutes. During the process of the vanadium-containing molten iron flowing from the spout to the ladle, the stream of molten iron comes into full contact with the air stream, and the vanadium in the molten iron oxidizes (the principle of vanadium extraction by atomization), which leads to a decrease in the vanadium content in the molten iron. As a result, vanadium-containing slag is generated and floats on the surface of the ladle. After the molten iron is sent to the steelmaking plant for pretreatment, the vanadium-containing slag on the surface cannot be recovered, resulting in a certain amount of vanadium loss and increasing the smelting cost.

[0036] Based on this, according to one aspect of the present invention, an apparatus 100 for increasing the vanadium content in molten iron is provided, with reference to...Figures 1 to 4 The device 100 includes an annular pipe 102 and a plurality of first vent holes 104. The annular pipe 102 is located above the rim of the ladle 108 and below and aligned with the spout 112 of the trough 110. The first vent holes 104 are located on the upper side of the annular pipe 102 and are used to spray protective gas toward the spout 112 to form a longitudinal protective gas curtain 116 for the molten iron flow 114. The oxygen content of the protective gas is below a first threshold, for example, below 3%, or it is an oxygen-free gas, such as nitrogen.

[0037] In some embodiments, the device 100 may further include a gas source 120, which can be connected to the air inlet 124 of the annular pipe 102 via a gas pipe 122 to supply gas to the annular pipe 102 to form a protective air curtain. Figure 1 .

[0038] Compared with existing solutions, the device 100 of the present invention forms a protective gas curtain for the molten iron flow through an annular pipe during the process of transporting molten iron to the molten iron ladle, which reduces the contact between molten iron and oxygen, thereby reducing vanadium oxidation loss and improving yield.

[0039] According to some embodiments of the present invention, the protective gas may include combustion exhaust gas, which is recovered from other combustion processes. This can reduce gas costs, alleviate exhaust gas treatment workload, and is more environmentally friendly.

[0040] In a further embodiment of the present invention, the annular pipe 102 is connected to the exhaust gas pipe of the hot blast stove. In this embodiment, the gas source 120 is the exhaust gas pipe of the hot blast stove, realizing the recycling of combustion exhaust gas, which is more environmentally friendly and lower in cost.

[0041] According to some embodiments of the present invention, reference Figure 1 , Figure 2 and Figure 4 The device 100 also includes a plurality of second exhaust holes 106 located on the outer side of the annular pipe 102. The second exhaust holes 106 are used to spray protective gas in the outer peripheral direction of the annular pipe 102 to form a horizontal protective air curtain 118. The horizontal protective air curtain 118 can isolate the air entering from the opening of the molten iron ladle 108, and further isolate oxygen, thus forming protection for the molten iron flow 114.

[0042] In a further embodiment, the device 100 may also include a plurality of third vent holes (not shown) located on the lower side of the annular pipe 102. The third vent holes are used to spray protective gas into the molten iron ladle 108 to reduce the oxygen content in the molten iron ladle 108, thereby better isolating oxygen and forming protection for the molten iron flow 114.

[0043] According to several embodiments of the present invention, the diameter of the annular pipe 102 is 3000-4000 mm, which can better cover the rim of the molten iron ladle 108 and form protection for the molten iron flow 114.

[0044] In some embodiments of the invention, the diameter of the first vent 104 is 2 to 5 times the diameter of the second vent 106, thereby directing more gas to the longitudinal protective air curtain 116 and providing better protection for the falling molten iron flow 114. In some preferred embodiments, the diameter of the first vent 104 is 10 mm and the diameter of the second vent 106 is 4 mm, to achieve better distribution of protective gas between the longitudinal protective air curtain 116 and the horizontal protective air curtain 118.

[0045] According to one embodiment of the present invention, the angular spacing between adjacent second exhaust holes 106 is 15-20 degrees. The angular spacing refers to the angle formed by the line connecting adjacent second exhaust holes 106 and the center position of the annular pipe 102, thereby achieving a better horizontal protective air curtain 118 configuration.

[0046] In addition, see Figure 1 According to one embodiment of the present invention, the annular pipe 102 is located 5 to 10 cm above the molten iron ladle 108. This height allows for better protection of the molten iron flow 114 without affecting the normal production process.

[0047] Based on this device 100, the inventors of this application conducted a series of comparative experiments as follows:

[0048] Benchmark example:

[0049] Under normal conditions without using device 100, the molten iron ladle takes 32 minutes to fill with molten iron. The spout is 7m from the bottom of the ladle and 3m from the edge of the ladle. The vanadium-containing molten iron flows into the ladle through the spout. When the molten iron first enters the ladle, 7m of the molten iron stream is exposed to the air. Even when the ladle is almost full, 3m of the molten iron stream is still exposed to the air. During this process, the vanadium-containing molten iron stream comes into full contact with the air (similar to atomization vanadium extraction), which causes some vanadium to be oxidized, reducing the vanadium content in the molten iron. The vanadium content in the molten iron at the spout is 0.325%, and after the ladle is filled with vanadium-containing molten iron, the vanadium content in the molten iron inside the ladle is 0.313%, a decrease of 0.012 percentage points (3.69%).

[0050] Comparative Example 1:

[0051] When using device 100, the time to fill the ladle with molten iron is 31 minutes. The spout is 7m from the bottom of the ladle and 3m from the rim. At the moment the iron is tapped from the taphole, combustion furnace exhaust gas is introduced into the annular pipe along the rim of the ladle. The composition and flow rate of the exhaust gas are shown in Table 1 below. The vanadium-containing molten iron flows into the ladle through the spout, and the flow path is protected by the combustion furnace exhaust gas, preventing contact with large amounts of air and thus reducing the oxidation of vanadium in the molten iron. The vanadium content in the molten iron at the spout is 0.325%, and after the ladle is filled with vanadium-containing molten iron, the vanadium content in the molten iron inside the ladle is 0.320%, a decrease of 0.005 percentage points (1.53%).

[0052] Table 1

[0053] CO2 O2 CO N2 Flow / m3 / h Pressure / KPa Hot blast stove furnace exhaust gas 25.35 2.52 0.01 72.12 3000 150

[0054] Comparative Example 2:

[0055] When using device 100, the time to fill the ladle with molten iron is 33 minutes. The spout is 7m from the bottom of the ladle and 3m from the rim. At the moment the iron is tapped from the taphole, combustion furnace exhaust gas is introduced into the annular pipe along the rim of the ladle. The composition and flow rate of the exhaust gas are shown in Table 2. The vanadium-containing molten iron flows into the ladle through the spout, and the flow path is protected by the combustion furnace exhaust gas, preventing contact with large amounts of air and thus reducing the oxidation of vanadium in the molten iron. The vanadium content in the molten iron at the spout is 0.324%, and after the ladle is filled with vanadium-containing molten iron, the vanadium content in the molten iron inside the ladle is 0.320%, a decrease of 0.004 percentage points (1.23%).

[0056] Table 2

[0057] CO2 O2 CO N2 Flow / m3 / h Pressure / KPa Hot blast stove furnace exhaust gas 25.35 2.52 0.01 72.12 5000 150

[0058] Comparative Example 3:

[0059] When using device 100, the time to fill the ladle with molten iron is 31 minutes. The spout is 7m from the bottom of the ladle and 3m from the rim. Nitrogen gas is introduced into the annular pipe along the ladle rim just as the iron is tapped. The nitrogen content and flow rate are shown in Table 3. The vanadium-containing molten iron flows into the ladle through the spout, and the flow stream is protected by nitrogen gas, preventing contact with large amounts of air and thus reducing the oxidation of vanadium in the molten iron. The vanadium content in the molten iron at the spout is 0.318%, and after the ladle is filled with vanadium-containing molten iron, the vanadium content in the molten iron inside the ladle is 0.315%, a decrease of 0.003 percentage points (0.09%).

[0060] Table 3

[0061] N2 Flow / m3 / h Pressure / KPa Nitrogen 99.5 3000 150

[0062] Comparative Example 4:

[0063] When using device 100, the time to fill the ladle with molten iron is 33 minutes. The spout is 7m from the bottom of the ladle and 3m from the rim. Nitrogen gas is introduced into the annular pipe along the ladle rim just as the iron is tapped. The nitrogen content and flow rate are shown in Table 4. The vanadium-containing molten iron flows into the ladle through the spout, and the flow stream is protected by nitrogen gas, preventing contact with large amounts of air and thus reducing the oxidation of vanadium in the molten iron. The vanadium content in the molten iron at the spout is 0.315%, and after the ladle is filled with vanadium-containing molten iron, the vanadium content in the molten iron inside the ladle is 0.313%, a decrease of 0.002 percentage points (0.06%).

[0064] Table 4

[0065] N2 Flow / m3 / h Pressure / KPa Nitrogen 99.5 5000 150

[0066] According to another aspect of the present invention, a method for increasing the vanadium content in molten iron is also provided, comprising the following steps:

[0067] Molten iron containing vanadium is poured into the molten iron ladle 108 through the spout 112 of the iron trough 110;

[0068] Protective gases are ejected from the molten iron ladle 108 in the direction of the spout 112 and the horizontal direction, respectively, to form a longitudinal protective gas curtain 116 and a horizontal protective gas curtain 118, wherein the oxygen content in the protective gas is lower than a first threshold.

[0069] Similarly, it should be understood that, where there is no conflict, all the embodiments, features, and advantages described above for the apparatus 100 for increasing the vanadium content in molten iron according to the present invention are equally applicable to the method for increasing the vanadium content in molten iron according to this other aspect of the present invention. That is, all the embodiments and variations thereof described above can be directly transferred and incorporated herein. For the sake of brevity, they will not be repeated here.

[0070] In summary, compared with the prior art, the present invention proposes an apparatus and method for increasing the vanadium content in molten iron. During the process of transporting molten iron to the molten iron ladle 108, a protective gas curtain 116 and 118 for the molten iron flow 114 is formed through the annular pipe 102, which reduces the contact between molten iron and oxygen, thereby reducing the oxidation loss of vanadium and improving the yield.

[0071] It should be understood that, provided it is technically feasible, the technical features listed above for different embodiments can be combined with each other to form other embodiments within the scope of this invention.

[0072] In this application, the use of antonymous conjunctions is intended to include the conjunction itself. The use of definite or indefinite articles is not intended to indicate cardinality. Specifically, references to “the” object or to “a” and “one” objects are intended to indicate one of a plurality of such objects. Furthermore, the conjunction “or” may be used to convey simultaneous features rather than mutually exclusive schemes. In other words, the conjunction “or” should be understood as including “and / or”. The term “including” is inclusive and has the same scope as “contains”.

[0073] The above embodiments are possible examples of implementations of the present invention and are provided only to enable those skilled in the art to clearly understand the principles of the present invention. Those skilled in the art should understand that the above discussion of any embodiment is merely exemplary and is not intended to imply that the scope of the disclosed embodiments of the present invention (including the claims) is limited to these examples. Under the overall concept of the present invention, the technical features of the above embodiments or different embodiments can also be combined with each other to produce many other variations of different aspects of the embodiments of the present invention as described above. For the sake of brevity, these variations are not provided in the specific embodiments. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of the present invention should be included within the scope of protection claimed by the present invention.

Claims

1. An apparatus for increasing the vanadium content in molten iron, characterized in that, include: An annular pipe located above the edge of the molten iron ladle, the annular pipe being positioned below the spout of the trough and aligned with the spout; A plurality of first vent holes are located on the upper side of the annular pipe. The first vent holes are used to spray protective gas toward the nozzle to form a longitudinal protective gas curtain for the molten iron flow. Several second vent holes are located on the outer side of the annular pipe. These second vent holes are used to spray protective gas towards the outer periphery of the annular pipe to form a horizontal protective gas curtain against the molten iron flow. Several third vent holes are located on the lower side of the annular pipe. The third vent holes are used to spray protective gas into the molten iron ladle to reduce the oxygen content in the molten iron ladle. The oxygen content in the protective gas is lower than a first threshold.

2. The apparatus for increasing the vanadium content in molten iron according to claim 1, characterized in that, The protective gas includes combustion exhaust gas.

3. The apparatus for increasing the vanadium content in molten iron according to claim 2, characterized in that, The annular pipe is connected to the exhaust pipe of the hot blast stove.

4. The apparatus for increasing the vanadium content in molten iron according to claim 1, characterized in that, The diameter of the annular pipe is 3000-4000mm.

5. The apparatus for increasing the vanadium content in molten iron according to claim 1, characterized in that, The diameter of the first vent hole is 2 to 5 times the diameter of the second vent hole.

6. The apparatus for increasing the vanadium content in molten iron according to claim 5, characterized in that, The diameter of the first vent is 10 mm, and the diameter of the second vent is 4 mm.

7. The apparatus for increasing the vanadium content in molten iron according to claim 1, characterized in that, The angular spacing between adjacent second exhaust holes is 15-20 degrees.

8. The apparatus for increasing the vanadium content in molten iron according to claim 1, characterized in that, The annular pipe is located 5 to 10 cm above the edge of the molten iron ladle.

9. A method for increasing the vanadium content in molten iron, characterized in that, The apparatus for increasing the vanadium content in molten iron according to any one of claims 1 to 8 includes the following steps: Molten iron containing vanadium is poured into the molten iron ladle through the spout of the iron trough; Protective gas is ejected from the molten iron ladle in the direction of the spout and in the horizontal direction to form a longitudinal protective gas curtain and a horizontal protective gas curtain, respectively, and is also ejected into the molten iron ladle; wherein the oxygen content in the protective gas is lower than a first threshold.

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