Direct-current submerged arc furnace bottom electrode

Abstract

The utility model provides a direct-current submerged arc furnace bottom electrode which is used for producing iron alloy, the bottom electrode serves as a bottom anode, and a cathode is made of carbon materials and is arranged at the top end of a direct-current submerged arc furnace. The bottom anode comprises an upper section, a middle section and a lower section, the upper section is made of a non-oxide high-temperature material and a carbon material of which the elements are the same as those of the produced iron alloy, the middle section conducts electricity through a plurality of metal steel bars or steel sheets, and a dry type alkaline vibration ramming material layer and a heat preservation refractory material layer are arranged in the gap part between every two adjacent metal steel bars or steel sheets. The utility model is used for the direct current submerged arc furnace, the power consumption of the product is reduced by 15-25%, the electrode consumption is reduced by about 50%, the flicker influence on the power grid is also obviously reduced, the environmental pollution caused by noise and the like is reduced by 30%, the production is more stable, and the smelting time is shortened.

Description

Technical Field

[0001] The utility model belongs to the field of direct current ore-heating furnaces, in particular to a bottom electrode of a direct current ore-heating furnace. Background Art

[0002] For a DC submerged arc furnace with a bottom electrode, the upper end of the bottom electrode contacts the alloy liquid. Therefore, the bottom electrode should not react with the alloy liquid, or the reaction should also generate a high-temperature solid phase. For example, in a submerged arc furnace that produces ferrosilicon, the bottom electrode composition should preferably not dissolve ferrosilicon or be corroded by ferrosilicon. Conductive materials that can meet such conditions are carbon and silicon carbide materials. When the equipment is running, the following reaction occurs: Fe-Si+C→SiC+Fe3C. Similarly, when producing manganese silicon and silicon, silicon carbide, a high-temperature phase, can be generated, which is not easily dissolved in silicon and manganese silicon. In particular, the solubility of carbon in ferrosilicon alloy liquid is very low, so it is not easily corroded. If ferrochrome is produced, a high-temperature chromium carbide phase is also generated at the top of the carbon bottom electrode. It also has good oxidation resistance, and chromium carbide, silicon carbide, etc. are all conductive. In this way, carbon-based materials can be used as good bottom electrode materials for DC submerged arc furnaces.

[0003] For the ore-fired furnaces for producing ferroalloys, the AC ore-fired furnaces are currently the main ones, which do not require the furnace bottom to be conductive. Therefore, the furnace bottom is mostly made of carbon bricks, magnesium ramming materials and high-alumina bricks. Except for carbon bricks, all other materials are non-conductive. For DC ore-fired furnaces that require bottom conductivity, such furnace bottoms will not work. Carbon bricks can be used because they have conductivity, but they also need to meet the conductivity requirements.

[0004] The development of high-power thyristors in the late last century led to the development of DC arc furnaces and DC ore-heating furnaces. DC ore-heating furnaces have the following characteristics: 1) Small impact on the power grid; 2) High power factor, above 0.95, while AC furnaces are only 0.6-0.8, which significantly reduces reactive power and energy consumption; 3) Electrode consumption is significantly reduced. For a DC ore-heating furnace with a single carbon cathode, carbon electrode consumption is reduced by 50%; 4) Low noise and a better environment; 5) Easy arc operation, stable operation, improved energy absorption rate, and energy saving of more than 10%. In view of the above advantages of DC ore-heating furnaces, DC ore-heating furnaces are the development direction.

[0005] Since the development of DC arc furnace, the two major problems that have restricted its development are high-power rectifier and bottom electrode. When high-power thyristor is passed, the development of large-scale ultra-high power DC arc furnace and arc furnace is no longer a problem, but the bottom electrode is still on the way. There are four modes of DC arc furnace bottom electrode, see the table below.

[0006]

[0007] Because the VAI steel sheet type DC furnace has small eddy current, the bottom electrode at the bottom of the furnace is safe and energy-saving. The bottom electrode is hot and cold repaired with conductive hot repair materials and cold ramming materials at the bottom of the furnace. The use and maintenance are the same as the current AC furnace, and the service life can reach thousands or even tens of thousands of heats. This will significantly reduce costs, improve operating efficiency and increase service life. Patents 202123373785.1 and 201610545796.8 applied for by the applicant disclose the bottom electrode of a DC arc furnace. This structure is equivalent to combining the advantages of the currently developed bottom electrodes, and this will also become the development direction of the bottom electrode of a DC arc furnace for steelmaking.

[0008] DC submerged arc furnace is different from DC arc furnace for steelmaking. The bottom electrode of the former contacts alloys such as silicon, ferrosilicon, ferromanganese, ferrochrome, ferronickel, alloy slag and corresponding ore raw materials, while the latter contacts molten steel, steel slag and some auxiliary materials, and the former requires a longer service life. The bottom working layer of submerged arc furnace is mostly made of carbonaceous materials such as carbon bricks. Carbonaceous materials are conductive, which can meet the requirement of bottom electrode conductivity. Carbon bricks are conductive and have high thermal conductivity. However, carbon bricks cannot be used for the bottom working layer of DC arc furnace for steelmaking. It will dissolve into the molten steel quickly, which affects the service life and the quality of steel.

[0009] Patent 202222365538.5 discloses a single-electrode DC arc furnace, a DC submerged arc furnace bottom electrode, and 201520077072.6 discloses a DC arc furnace that uses conductive carbon bricks, especially graphite electrodes, for the bottom electrode of the DC submerged arc furnace. The bottom shell temperature is too high to work properly due to the high thermal conductivity. This is like the ABB conductive refractory furnace bottom, which can be ventilated to cool the bottom, which will result in too high energy consumption. If a highly oxidizing substance is smelted, the bottom graphite electrode will be consumed too quickly due to oxidation. If scrap steel is melted, the graphite carbon will be consumed too quickly because it dissolves too quickly into the steel. This not only increases production costs, but also poses a greater risk to safety.

[0010] Patents 201910100472.7, 201811467548.1 and 201920472066.9 use multiple positive and negative electrodes on the top of the furnace without a bottom anode. This increases the number of electrodes, resulting in a complex structure, excessive investment and increased consumption of graphite electrodes. The increase in the number of top electrodes leads to frequent replacements, which affects the operating rate of the equipment. The current does not flow to the bottom, the stirring effect deteriorates, and the temperature distribution is uneven. Therefore, the steelmaking effect deteriorates.

[0011] Patent 202020991381.5 discloses an energy-saving DC electric arc furnace, which introduces an anode composed of a bottom electrode and a side electrode, and a single graphite rod cathode is used on the top. This leads to arc deviation and uneven heating and melting due to the asymmetry of the anode.

[0012] Patent 200810086120.2 discloses a large-scale DC hollow electrode sealed submerged arc furnace, the bottom electrode of which is made of magnesia carbon bricks, which are close to the molten pool and then connected to the circuit from the bottom with a wiring board. This will cause the wiring board to have a very high temperature due to the high thermal conductivity of the conductive magnesia carbon bricks, resulting in a temperature of more than 1400°C, and even melt the wiring board, resulting in failure to work normally.

[0013] Patent 202020991381.5 discloses an energy-saving DC ore-fired furnace. The patent only says that the bottom electrode uses a conductive ramming material, generally a cold ramming paste. As we all know, the asphalt content of the cold ramming paste is above 16%, especially to maintain a long furnace bottom service life, the bottom thickness must be at least 1000mm. Baking of a ramming layer of such thickness is an extremely serious problem. Baking for one month may not meet the requirement of volatile matter release without swelling. Even if the temperature is quickly raised to remove the volatile matter, the bottom electrode will swell and become scrapped. In addition, the sidewall electrode will cause current asymmetry and the electrode surface temperature will be too high, making it difficult to operate normally.

[0014] Patent 201710468533.6 discloses a DC electric arc furnace. The thickness of the magnesium-calcium ramming material at the bottom of the patent is 1 / 3, and the thermal conductivity of the copper plate is too high, which may cause the temperature of the electrode at the bottom of the furnace to be too high or even red, posing a great risk to safety and excessive energy consumption.

[0015] Therefore, up to now, DC electric arc furnaces in my country are mainly concentrated on multiple top electrodes, with the cathode and anode both at the top of the electric arc furnace. There are relatively few electric arc furnaces with bottom electrodes as bottom anodes, and the main bottleneck lies in the materials and structure used for the bottom electrodes. Utility Model Content

[0016] In view of the technical problems existing in the above-mentioned DC ore-fired furnace, the utility model proposes a DC ore-fired furnace bottom electrode using a bottom electrode as a bottom anode. When used in a DC ore-fired furnace, the power consumption of the product is reduced by 15-25%, the electrode consumption is reduced by about 50%, the flickering effect on the power grid is also significantly reduced, the environmental pollution such as noise is reduced by 30%, the production is more stable, the smelting time is shortened, and the production efficiency is significantly improved. It has positive significance in energy conservation and emission reduction, cost reduction and efficiency improvement, and dual-carbon economy.

[0017] In order to achieve the above-mentioned purpose, the technical solution adopted by the utility model is as follows: the utility model provides a DC ore-fired furnace bottom electrode for producing ferroalloys, the bottom electrode serves as a bottom anode, the opposite polarity of the bottom anode is a cathode and preferably the cathode is a graphite electrode, the graphite electrode is arranged at the top of the DC ore-fired furnace, the current of the DC ore-fired furnace is connected from the graphite electrode to the positive electrode of the power supply through the melt and the bottom anode in the DC ore-fired furnace to form a loop, the bottom anode includes an upper section, a middle section and a lower section, the upper section is connected to the ferroalloy to be produced, the upper section adopts non-oxide high-temperature materials and carbon materials of the same elements as the ferroalloy to be produced, the middle section and the lower section conduct electricity through a plurality of metal conductive elements, a dry alkaline vibration ramming material layer and a thermal insulation refractory material layer are arranged in the gap part of adjacent metal conductive elements, and the thermal insulation refractory material layer is arranged below the dry alkaline vibration ramming material layer.

[0018] Preferably, the non-oxide high-temperature material and carbon material used in the upper section are conductive materials, and the conductive material is a high-temperature carbide, boride, nitride or carbon material. The upper section is used to react with the ferroalloy under high temperature conditions to form corresponding high-temperature carbides.

[0019] Preferably, the dry alkaline vibration ramming material used in the middle section is a metal oxide associated with ferroalloy or a high-temperature alkaline oxide.

[0020] Preferably, the high temperature alkaline oxide is MgO, CaO or magnesium aluminate spinel.

[0021] Preferably, the thermal insulation refractory material layer is made of closed pore and nano-micro pore materials, and the closed pore and nano-micro pore materials are fumed silica, nano-alumina or nano-magnesia.

[0022] Preferably, the thickness of the lower section is ≤20% of the thickness of the entire DC ore furnace bottom; the thickness of the middle section is ≤40% of the thickness of the bottom electrode; the remainder is the upper section and its thickness is ≥40% of the thickness of the entire DC ore furnace bottom.

[0023] Preferably, the non-oxide high-temperature material and carbon material of the upper section are conductive vibration ramming material layers of dry carbon, silicon carbide or chromium carbide, and a plurality of evenly distributed carbon bricks are also arranged inside the upper section.

[0024] Preferably, the metal conductive element is a metal steel rod or steel sheet, the cross-sectional area of ​​the metal steel rod or steel sheet is ≥1.25×current intensity, and the contact area between the metal steel rod or steel sheet and the upper section is ≥3.5×current intensity, wherein the cross-sectional area and the contact area are both measured in square millimeters, and the current intensity is measured in amperes.

[0025] Compared with the prior art, the advantages and positive effects of the utility model are:

[0026] 1. The utility model provides a DC ore-fired furnace bottom electrode, which uses the bottom electrode as the bottom anode and is used in the DC ore-fired furnace. The selection of the materials of the upper section, the middle section and the lower section of the bottom electrode and the design of the overall structure enable the bottom anode to interact with the top cathode, and the heat generated by the current and the arc light to react the reactants in the furnace at a high temperature to generate ferroalloy and molten slag. The production process does not require air cooling to operate normally, which can meet the needs of the DC ore-fired furnace to produce ferroalloys, and the power consumption of the product is reduced by 15-25%, the electrode consumption is reduced by about 50%, the flickering effect on the power grid is also significantly reduced, the noise and other environmental pollution are reduced by 30%, the production is more stable, and the smelting time is shortened. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 A schematic diagram of a DC ore-fired furnace bottom electrode in a DC ore-fired furnace provided in an embodiment;

[0029] In the above figures, 1. furnace wall lining bricks; 2. electric furnace shell; 3. furnace bottom ramming material layer; 4. magnesium bricks or carbon bricks around the furnace bottom electrode; 5. bottom electrode; 6. upper section; 61. conductive vibration ramming material layer; 62. carbon bricks; 7. middle section; 71. dry alkaline vibration ramming material layer; 8. lower section; 81. thermal insulation refractory material layer; 9. steel sheet. DETAILED DESCRIPTION

[0030] In order to more clearly understand the above-mentioned purpose, features and advantages of the utility model, the utility model is further described below in conjunction with the accompanying drawings and embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict. For the convenience of description, if the words "upper", "lower", "left" and "right" appear below, they only indicate that the upper, lower, left and right directions are consistent with the drawings themselves, and do not limit the structure.

[0031] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways than those described herein. Therefore, the present invention is not limited to the specific embodiments of the following disclosure.

[0032] like Figure 1As shown, the utility model provides a DC ore-fired furnace bottom electrode, which is used for producing ferroalloys. The bottom electrode 5 is used as a bottom anode. The opposite polarity of the bottom anode is a cathode, and the cathode is preferably a graphite electrode. The graphite electrode is arranged at the top of the DC ore-fired furnace. The current of the DC ore-fired furnace forms a circuit from the graphite electrode through the melt in the DC ore-fired furnace and the bottom anode to the positive electrode of the power supply. The bottom anode includes an upper section 6, a middle section 7 and a lower section 8. The upper section 6 is connected to the ferroalloy to be produced. The upper section 6 uses non-oxide high-temperature materials and carbon materials with the same elements as the ferroalloy to be produced. The middle section 7 conducts electricity through multiple metal conductive elements. A dry alkaline vibration ramming material layer 71 and a heat-insulating refractory material layer 81 are arranged in the gap between adjacent metal conductive elements. The heat-insulating refractory material layer 81 is arranged below the dry alkaline vibration ramming material layer 71. The non-oxide high-temperature material and carbon material of the upper section 6 are conductive vibration ramming material layers of dry carbon, silicon carbide or chromium carbide. A plurality of evenly distributed carbon bricks 62 are also arranged inside the upper section 6.

[0033] Example 1

[0034] A small-scale submerged arc furnace, with an inner diameter of 5000mm, a transformer capacity of 18.5MVA, a maximum current intensity of 25KA, and a bottom anode made of stainless steel sheet 9 and a carbon conductive vibration ramming material layer as conductive materials. The thickness of the steel sheet 9 is 2mm, and the cross-sectional area of ​​the steel sheet 9 accounts for 0.046m2 of the electrode area. 2 The safe current density of steel sheet 9 is 550KA / m 2 The area of ​​the 5th electrode zone at the bottom of the small furnace is 0.05 / 1.6% = 3.125m 2 , that is, the diameter Φ is 1995mm. In order to prevent current concentration, the current density at the bottom of the small furnace is designed to be uniform, that is, it is designed to be 8KA / m 2 . This requires 6 circles, the diameter of the outermost circle is 1950mm, and the distance from the adjacent circle is about 150mm, that is, the diameters are 508, 823, 1103, 1401, 1683, and 1957mm respectively. The above-mentioned steel sheet 9 is welded to the bottom plate, and then connected to the anode of the power supply; the small furnace bottom is fixed to the furnace bottom; first, a 120mm insulating refractory material layer is applied in the gap between the steel sheets 9, and the insulating refractory material layer 81 uses MgO nanomaterials, and then a 600mm dry alkaline vibration ramming material layer is applied, and the dry alkaline vibration ramming material layer 71 uses magnesium calcium ramming material, and then a carbon conductive vibration ramming material layer is applied until it is flush with the 1200mm steel sheet 9; then 500mm of carbon bricks are laid upwards for standby use; the thermal resistance from top to bottom is 77+32+266+372=747. Therefore, the bottom surface temperature is 169℃, q=1983w / m 2 The upward interface temperatures are 907°C, 1434°C, 1497°C, and 1650°C (temperature of alloy liquid in the furnace). Therefore, it can operate normally without air cooling.

[0035] Example 2

[0036] A medium-sized submerged arc furnace has an inner diameter of 8000mm, a transformer capacity of 35MVA, a maximum current intensity of 46KA, and a bottom anode made of stainless steel sheet 9 and a carbon conductive vibration ramming material layer as conductive materials. The thickness of the steel sheet 9 is 1.5mm, and the safe current density of the steel sheet 9 is 650KA / m 2 The cross-sectional area of ​​steel sheet 9 accounts for 0.0707m of the electrode area. 2 The area of ​​the 5th electrode zone at the bottom of the small furnace is 0.0707 / 1.6% = 4.42m 2 , that is, the diameter of the small furnace bottom is 2600mm. In order to prevent current concentration, the current density at the small furnace bottom is designed to be uniform, that is, it is designed to be 10KA / m 2 . This requires 11 circles, the diameter of the outermost circle is 2520mm, and the distance from the adjacent circle is about 100mm, that is, the diameters are 390, 631, 855, 1072, 1495, 1702, 1908, 2113, 2317, and 2520 respectively. The above-mentioned steel sheet 9 is welded to the bottom plate and then connected to the anode of the power supply. The small furnace bottom is fixed to the furnace bottom. In the gap between the steel sheets 9, a 150mm insulating refractory material layer is first applied, and the insulating refractory material layer 81 uses MgO nanomaterials, and then a 600mm dry alkaline vibration ramming material layer is applied, and the dry alkaline vibration ramming material layer 71 uses magnesium calcium ramming material, and then a carbon conductive vibration ramming material layer is applied until it is flush with the 1500mm steel sheet 9; then 800mm of carbon bricks are laid upwards for standby use. The thermal resistance from top to bottom is 123+50+266+465=904. Therefore, the bottom surface temperature is 152°C, q = 1657w / m 2 The upward interface temperatures are 922°C, 1363°C, 1446°C, and 1650°C (temperature of alloy liquid in the furnace). Therefore, it can operate normally without air cooling.

[0037] Example 3

[0038] A large-scale submerged arc furnace, with an inner diameter of 12000mm, a transformer capacity of 63MVA, a maximum current intensity of 100KA, and a bottom anode made of steel sheet 9 and carbon conductive vibration ramming material layer as conductive materials. The thickness of the steel sheet 9 is 1mm, and the cross-sectional area of ​​the steel sheet 9 accounts for 1.67m of the electrode area. 2 The safe current density of steel sheet 9 is 600KA / m 2 The area of ​​the electrode zone 5 at the bottom of the small furnace is 0.167 / 1.6% = 10.4m 2 , that is, the diameter Φ is 3642mm. In order to prevent current concentration, the current density at the bottom of the small furnace is designed to be uniform, that is, it is designed to be 9.6KA / m 2. In this way, 27 circles are needed, the outermost circle has a diameter of 3642mm, and the distance from the adjacent circle is 55mm, that is, the diameters are 250, 405, 548, 687.5, 824, 958, 1091, 1223, 1355, 1485, 1616, 1746, 1875, 2003, 2130, 2256, 2381, 2505, 2628, 2750, 2871, 2991, 3110, 3228, 3345, 3461, 3576mm respectively. The above steel sheet 9 is welded to the bottom plate and then connected to the anode of the power supply. The small furnace bottom is fixed to the furnace bottom. First, a 150mm insulating refractory material layer is placed between the steel sheets 9. The insulating refractory material layer 81 is made of MgO nanomaterials. Then, a 650mm dry alkaline vibration ramming material layer is placed. The dry alkaline vibration ramming material layer 71 is made of magnesium-calcium ramming material. Then, a carbon conductive vibration ramming material layer is placed until it is flush with the 1300mm steel sheet 9. Then, 500mm of carbon bricks are laid upwards for standby use. The thermal resistance from top to bottom is 77+25+287+449=838. Therefore, the bottom surface temperature is 159°C, and q=1779w / m 2 The upward interface temperatures are 958°C, 1469°C, 1512°C, and 1650°C (temperature of alloy liquid in the furnace), so it can operate normally without air cooling.

[0039] The DC ore-fired furnace designed by the embodiments 1 to 3 has a basic structure including a furnace wall lining brick 1, an electric furnace shell 2, a furnace bottom ramming material layer 3 and magnesium bricks or carbon bricks 4 around the furnace bottom; and regarding the electrode part, the bottom electrode 5 is used as the bottom anode, and the graphite electrode is used as the cathode. The materials of the upper section 6, the middle section 7 and the lower section 8 of the bottom electrode 5 are selected and the overall structure is designed, so that the bottom anode and the top cathode interact with each other, and the heat generated by the current and the arc light causes the reactants in the furnace to react at high temperature to generate ferroalloy and slag melt. The production process does not require air cooling to operate normally, and can meet the needs of the DC ore-fired furnace for producing ferroalloy. From the actual results, the power consumption of the product is reduced by 15-25%, the electrode consumption is reduced by about 50%, the flickering effect on the power grid is also significantly reduced, the noise and other environmental pollution are reduced by 30%, the production is more stable, and the smelting time is shortened.

[0040] Furthermore, the non-oxide high temperature material and carbon material used in the upper section 6 are conductive materials, and the conductive material is a high temperature carbide, boride, nitride or carbon material. The upper section 6 is used to react with the iron alloy under high temperature conditions to form corresponding high temperature carbides. Carbides, nitrides and borides mean that they are not only resistant to high temperatures, but also must have good electrical conductivity, which is conducive to the smoothness of the circuit. In this way, the production process does not pollute the product, that is, it does not affect the purity of the product, and does not cause corrosion, thereby increasing the service life of the bottom electrode 5.

[0041] The dry alkaline vibration ramming material used in the middle section 7 is a metal oxide or a high-temperature alkaline oxide associated with ferroalloys. Among them, the high-temperature alkaline oxide is one or two of MgO, CaO and magnesium-aluminum spinel, which can meet the ultra-high temperature requirement of a smelting temperature of about 2800°C.

[0042] As for the heat-insulating refractory material layer 81, closed pores and nano-micro pore materials are used, and the closed pores and nano-micro pore materials are fumed white carbon black, nano-alumina or nano-magnesia, which can significantly reduce the thermal conductivity and improve the heat-insulating performance.

[0043] For safety and energy saving, the thickness of the lower section 8 is ≤20% of the thickness of the entire DC ore-heating furnace bottom; for safety and protection of the lower insulation material, the thickness of the middle section 7 is ≤40% of the thickness of the bottom electrode 5; the rest is the upper section 6 and its thickness is ≥40% of the thickness of the entire DC ore-heating furnace bottom. The metal conductive element is a metal steel bar or steel sheet 9 and its cross-sectional area is ≥1.25×current intensity; in order to prevent the interface resistance from being too large and ensure safety, the contact area between the metal steel bar or steel sheet 9 and the upper section 6 is ≥3.5×current intensity, where the cross-sectional area and contact area are both measured in square millimeters and the current intensity is measured in amperes. The furnace bottom shell temperature of such a bottom electrode 5 is very low and does not require cooling with cold air or water mist. This structure is energy-saving, safe and has a long service life, just like the currently mature AC ore-heating furnace. In particular, during use, the bottom electrode 5 can be hot-repaired or cold-repaired at any time, and its service life is as long as several years, which plays an important role in energy saving and cost reduction.

[0044] The above description is only a preferred embodiment of the present invention and does not limit the present invention in other forms. Any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes and apply it to other fields. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A DC ore-fired furnace bottom electrode for producing ferroalloys, characterized in that: The bottom electrode serves as a bottom anode, and the bottom anode includes an upper section, a middle section and a lower section. The upper section is connected to the produced ferroalloy, and the upper section adopts non-oxide high-temperature materials and carbon materials with the same elements as the produced ferroalloy. The middle section conducts electricity through multiple metal conductive elements, and a dry alkaline vibration ramming material layer and a thermal insulation refractory material layer are arranged in the gap part of adjacent metal conductive elements. The thermal insulation refractory material layer is arranged below the dry alkaline vibration ramming material layer.

2. A DC ore-fired furnace bottom electrode according to claim 1, characterized in that: The non-oxide high-temperature material and carbon material used in the upper section are conductive materials, and the conductive material is a high-temperature carbide, boride, nitride or carbon material. The upper section is used to react with the ferroalloy under high temperature conditions to form corresponding high-temperature carbides.

3. A DC ore-fired furnace bottom electrode according to claim 2, characterized in that: The dry alkaline vibration ramming material used in the middle section is a metal oxide associated with ferroalloy or a high-temperature alkaline oxide.

4. A DC ore-fired furnace bottom electrode according to claim 3, characterized in that: The high temperature basic oxide is MgO, CaO or magnesium aluminum spinel.

5. The DC ore-fired furnace bottom electrode according to claim 1, characterized in that: The thermal insulation refractory material layer adopts closed pores and nano-micro pore materials, and the closed pores and nano-micro pore materials are gas phase white carbon black, nano alumina or nano magnesia.

6. A DC ore-fired furnace bottom electrode according to any one of claims 1 to 5, characterized in that: The thickness of the lower section is ≤20% of the thickness of the entire DC ore furnace bottom; the thickness of the middle section is ≤40% of the thickness of the bottom electrode; the rest is the upper section and its thickness is ≥40% of the thickness of the entire DC ore furnace bottom.

7. A DC ore-fired furnace bottom electrode according to claim 6, characterized in that: The non-oxide high-temperature material and carbon material of the upper section are conductive vibration ramming material layers of dry carbon, silicon carbide or chromium carbide, and a plurality of evenly distributed carbon bricks are also arranged inside the upper section.

8. The DC ore-fired furnace bottom electrode according to claim 7, characterized in that: The metal conductive element is a metal steel rod or steel sheet, the cross-sectional area of ​​the metal conductive element is ≥1.25×current intensity, and the contact area between the metal conductive element and the upper section is ≥3.5×current intensity, wherein the cross-sectional area and the contact area are both measured in square millimeters, and the current intensity is measured in amperes.

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