Furnace opening method of depletion electric furnace

Abstract

The invention discloses a blowing-in method of a depletion electric furnace, which comprises the following steps of: laying an isolating layer at the bottom in a furnace body after furnace bricks are built in the furnace body; a natural gas burner is installed on the furnace body, the natural gas burner is opened and ignited, and flame of the natural gas burner is used for roasting the electrode; after the electrode is roasted and formed, the natural gas burner is closed, water-quenched slag is added into the furnace body, and the water-quenched slag is laid on the isolation layer to form a water-quenched slag layer; an arc striking device is mounted on the water quenching slag layer; power is supplied to the electrode for arc striking, so that an electric arc is formed between the electrode and the arc striking device; after the arc striking is successful, the power of the electrode is gradually increased to heat and melt the water-quenched slag, the water-quenched slag continues to be supplemented into the furnace, and in the process of gradually increasing the power of the electrode, the maximum heating speed of the furnace brick per hour is smaller than 25 DEG C per hour. The blowing-in method of the depletion electric furnace has the advantages of being short in roasting process, small in smoke pollution, long in service life of the furnace lining and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal smelting, in particular to a method for starting up a poor furnace. BACKGROUND

[0002] When the poor furnace is restarted after a long-term shutdown or replacement of furnace bricks, it needs to be restarted,

[0003] The starting-up method of the poor furnace in the related art has the problems that the furnace bricks are prone to peeling off during the heating process, the service life of the furnace lining is reduced, and the furnace bricks need to be frequently replaced during use, and one replacement of the furnace bricks requires a high cost. SUMMARY

[0004] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application provides a method for starting up a poor furnace, which has the advantages of short baking process, small flue gas pollution, long service life of furnace lining, etc.

[0005] To achieve the above-mentioned purpose, according to an embodiment of the present application, a method for starting up a poor furnace is provided, the poor furnace comprising a furnace body and an electrode, at least a part of the electrode extending into the furnace body, the method comprising the following steps:

[0006] S1, after the furnace body is built with furnace bricks, laying an isolation layer on the bottom of the furnace body;

[0007] S2, installing a natural gas burner on the furnace body, opening and igniting the natural gas burner, and using the flame of the natural gas burner to bake the electrode;

[0008] S3, after the electrode is baked and formed, closing the natural gas burner, adding water quenched slag into the furnace body and laying the water quenched slag above the isolation layer to form a water quenched slag layer;

[0009] S4, installing an arc striking device on the water quenched slag layer;

[0010] S5, supplying power to the electrode to strike an arc to form an electric arc between the electrode and the arc striking device;

[0011] S6, after the arc striking is successful, gradually increasing the power of the electrode to heat and melt the water quenched slag, continuously adding water quenched slag into the furnace, until the depth of the melt in the furnace body reaches 1600-2000mm, and the starting-up is completed, wherein during the gradual increase of the power of the electrode, the maximum temperature rise of the furnace bricks per hour is less than 25 degrees Celsius.

[0012] The method for starting up a poor furnace according to the embodiment of the present application has the advantages of short baking process, small flue gas pollution, long service life of furnace lining, etc.

[0013] In addition, the method for starting up the depletion furnace according to the above-mentioned embodiment of the present application can further have the following additional technical features:

[0014] According to one embodiment of the present application, in step S6, the step of gradually increasing the power of the electrode includes the following steps:

[0015] Raising the temperature of the furnace brick from normal temperature to 150 degrees Celsius at a rate of 0-5 degrees Celsius per hour within 20-30 hours, and keeping the temperature for 70-75 hours;

[0016] Raising the temperature of the furnace brick from 150 degrees Celsius to 250 degrees Celsius at a rate of 5-10 degrees Celsius per hour within 8-12 hours, and keeping the temperature for 45-55 hours;

[0017] Raising the temperature of the furnace brick from 250 degrees Celsius to 350 degrees Celsius at a rate of 5-10 degrees Celsius per hour within 8-12 hours, and keeping the temperature for 45-55 hours;

[0018] Raising the temperature of the furnace brick from 350 degrees Celsius to 450 degrees Celsius at a rate of 10-15 degrees Celsius per hour within 8-12 hours, and keeping the temperature for 30-40 hours;

[0019] Raising the temperature of the furnace brick from 450 degrees Celsius to 600 degrees Celsius at a rate of 10-15 degrees Celsius per hour within 8-12 hours, and keeping the temperature for 10-15 hours;

[0020] Raising the temperature of the furnace brick from 600 degrees Celsius to 1200 degrees Celsius at a rate of 15-25 degrees Celsius per hour within 25-35 hours.

[0021] According to one embodiment of the present application, an observation hole is provided on the furnace body, and in step S2, the natural gas burner is installed in the observation hole, and a plurality of natural gas burners corresponding to each electrode are provided so that the flames of the plurality of natural gas burners completely surround the baking area of the electrode.

[0022] According to one embodiment of the present application, the length of the baking area is 1200-1600 mm, and in step S2, the electrode is baked and formed after the shell of the electrode in the baking area appears blue flame.

[0023] According to one embodiment of the present application, in step S3, the water-quenched slag is dry water-quenched slag with a water content of less than 1%, and the depth of the water-quenched slag layer is 800-1200 mm.

[0024] According to one embodiment of the present application, step S4 includes: digging a pit on the upper surface of the water-quenched slag layer, and installing the arc striking device in the pit, wherein the length of the pit is 1000-1200 mm, the width is 500-700 mm, and the depth is 900-1100 mm.

[0025] According to one embodiment of the present application, the step S4 further comprises: placing wooden baffle on the side wall of the pit to prevent the water-quenched slag on the side wall of the pit from sliding down.

[0026] According to one embodiment of the present application, the arc striking device comprises an upper coke layer, a lower coke layer and a steel mesh, the steel mesh is clamped between the upper coke layer and the lower coke layer, the steel mesh comprises a plurality of lower steels arranged in parallel and a plurality of upper steels arranged in parallel, the upper steels and the lower steels are perpendicular to each other, and the step S4 further comprises the following steps:

[0027] laying the lower coke layer with a thickness of 400-600 mm in the pit;

[0028] laying a plurality of the lower steels on the lower coke layer, the lower steels are oriented along the length direction of the pit;

[0029] laying a plurality of the upper steels above the lower steels, the upper steels are oriented along the width direction of the pit, and the upper steels and the lower steels are welded at the contact position to form the steel mesh;

[0030] laying the upper coke layer with a thickness of 200-400 mm above the steel mesh.

[0031] According to one embodiment of the present application, the step S5 comprises:

[0032] making the vertical distance between the electrode and the arc striking device be 100-200 mm;

[0033] powering the electrode, and the power is 3000-5000 kV·A;

[0034] making the electrode descend at a speed of 0.5-1 m / s;

[0035] forming arc light between the electrode and the arc striking device, and the arc striking is successful.

[0036] According to one embodiment of the present application, the isolation layer is a stainless steel plate with a thickness of 2-3 mm, the stainless steel plate covers the bottom of the furnace body and has a turned-up edge extending upward along the circumferential wall of the furnace body, the turned-up edge is tightly attached to the circumferential wall of the furnace body, and the height of the turned-up edge is 500-1000 mm.

[0037] Additional aspects and advantages of the present application will be given, partially in the following description, partially will become obvious from the following description, or will be learned by practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0038] The above and / or additional aspects and advantages of the present application will become apparent and more readily appreciated from the following description, taken in conjunction with the following drawings of which:

[0039] Figure 1 is a sectional view of a depletion electric furnace according to an embodiment of the present application.

[0040] Figure 2 is a sectional view of a depletion electric furnace according to an embodiment of the present application.

[0041] Figure 3 is a flowchart of a method of starting up a depletion electric furnace according to an embodiment of the present application.

[0042] Reference numerals: depletion electric furnace 1, furnace body 10, furnace brick 100, isolation layer 200, natural gas burner 300, water quenching slag layer 400, arc striking device 500, upper coke layer 510, lower coke layer 520, steel mesh 530, electrode 20, power supply short net system 21. DETAILED DESCRIPTION

[0043] The present application is made based on the discovery and realization of the inventors on the following facts and problems:

[0044] The method of starting up a depletion furnace in the related art has the problem that the furnace brick is easily peeled off during the heating process, reducing the service life of the furnace lining, and the furnace brick needs to be frequently replaced during use, which requires high cost for replacing the furnace brick once.

[0045] Specifically, the method of starting up a depletion furnace in the related art, in order to shorten the starting-up process and reduce the downtime required for waiting for starting up, only considers shortening the starting-up time, and all adopts a fast starting-up method.

[0046] The inventors of the present application have found through extensive research that the starting-up process of a depletion electric furnace is closely related to the service life of the furnace lining, and that, by using the fast starting-up method in the related art, the furnace brick heating process is improper, the heating speed is too fast, and the furnace brick is easily peeled off during the fast temperature raising process, reducing the service life of the furnace lining, resulting in the need to frequently replace the furnace brick during use, and increasing the use cost.

[0047] In addition, the method of starting up in the related art uses fuel with a high sulfur content such as wood to reduce fuel costs, which is not conducive to the treatment of flue gas generated during the starting-up process, and increases the cost of flue gas treatment.

[0048] Embodiments of the present application will be described in detail below, examples of which are shown in the accompanying drawings, in which the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application.

[0049] In the description of the present application, it needs to be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the features defined with "first", "second" can be explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0050] In the description of the present application, it needs to be understood that, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, or the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0051] The method for starting up a depletion electric furnace according to an embodiment of the present application will be described below with reference to the accompanying drawings.

[0052] As shown in Figures 1-3 The depletion electric furnace 1 comprises a furnace body 10 and an electrode 20, at least a part of the electrode 20 extending into the furnace body 10.

[0053] The method for starting up a depletion electric furnace comprises the following steps:

[0054] S1, after the furnace body 10 is built with furnace bricks 100, an isolation layer 200 is laid on the bottom in the furnace body 10 (the up-down direction is shown by the arrow in the figure);

[0055] S2, a natural gas burner 300 is installed on the furnace body 10, the natural gas burner 300 is opened and ignited, and the electrode 20 is baked by the flame of the natural gas burner 300;

[0056] S3, after the electrode 20 is baked and formed, the natural gas burner 300 is closed, water quenched slag is added into the furnace body 10 and laid above the isolation layer 200 to form a water quenched slag layer 400;

[0057] S4, an arc striking device 500 is installed on the water quenched slag layer 400;

[0058] S5, supplying power to the electrode 20 to perform arc striking to form an arc between the electrode 20 and the arc striking device 500;

[0059] S6, after the arc striking succeeds, gradually increasing the power of the electrode 20 to heat and melt the water quenched slag, continuously supplying the water quenched slag into the furnace, until the bath depth in the furnace body 10 reaches 1600-2000 mm, and the furnace is started, wherein, during the gradual increase of the power of the electrode 20, the maximum temperature rise of the furnace brick 100 per hour is less than 25 degrees Celsius.

[0060] According to the starting method of the depletion furnace, by using the natural gas burner 300, natural gas can be used as the fuel for the electrode 20 roasting, compared with the related art starting method using wood as the fuel, the roasting process can be shortened, the pollution generated in the roasting process can be reduced, the flue gas treatment in the roasting process is facilitated, and the flue gas treatment cost is reduced.

[0061] Moreover, by gradually increasing the power of the electrode 20 during the heating and melting of the water quenched slag and controlling the power of the electrode 20 to make the maximum temperature rise of the furnace brick 100 per hour less than 25 degrees Celsius, the furnace brick 100 has a lower temperature rise speed when the temperature is low, and the temperature rise speed of the furnace brick 100 gradually increases as the temperature of the furnace brick 100 rises, so that the furnace brick 100 slowly rises in temperature through the heating of the electrode 20, the service life of the furnace lining is reduced due to the thermal shock caused by the too fast temperature rise of the furnace brick 100, the replacement cycle of the furnace brick 100 is prolonged, and the use cost of the depletion furnace 1 is reduced.

[0062] In addition, by limiting the bath depth to 1600-2000 mm, the slag layer has a reasonable thickness, and the service life of the furnace lining is further prolonged.

[0063] Therefore, the starting method of the depletion furnace has the advantages of short roasting process, small flue gas pollution, long service life of the furnace lining, and the like.

[0064] The starting method of the depletion furnace according to the embodiments of the present application will be described below with reference to the accompanying drawings.

[0065] Advantageously, in step S6, the gradual increase of the power of the electrode 20 includes the following steps:

[0066] Rising the temperature of the furnace brick 100 from room temperature to 150 degrees Celsius at a speed of 0-5 degrees Celsius per hour within 20-30 hours, and keeping the temperature for 70-75 hours;

[0067] Rising the temperature of the furnace brick 100 from 150 degrees Celsius to 250 degrees Celsius at a speed of 5-10 degrees Celsius per hour within 8-12 hours, and keeping the temperature for 45-55 hours;

[0068] The temperature of the furnace bricks 100 was raised from 250 degrees Celsius to 350 degrees Celsius at a rate of 5-10 degrees Celsius per hour over 8-12 hours, and then held for 45-55 hours.

[0069] The temperature of the furnace bricks 100 was raised from 350 degrees Celsius to 450 degrees Celsius at a rate of 10-15 degrees Celsius per hour over 8-12 hours, and then held for 30-40 hours.

[0070] The temperature of the furnace bricks 100 was raised from 450 degrees Celsius to 600 degrees Celsius at a rate of 10-15 degrees Celsius per hour over 8-12 hours, and then held for 10-15 hours.

[0071] The temperature of the furnace bricks 100 was increased from 600 degrees Celsius to 1200 degrees Celsius at a rate of 15-25 degrees Celsius per hour over 25-35 hours.

[0072] This allows the furnace brick 100 to have a lower heating rate when the temperature is low, and the heating rate of the furnace brick 100 is gradually increased as the temperature of the furnace brick 100 rises, thereby avoiding thermal shock to the furnace brick 100 and extending the service life of the furnace lining.

[0073] Specifically, as shown in the figure, the furnace body 10 is provided with an observation hole. In step S2, a natural gas burner 300 is installed in the observation hole, and each electrode 20 corresponds to multiple natural gas burners 300 so that the flames of the multiple natural gas burners 300 completely surround the baking area of ​​the electrode 20. Specifically, as... Figure 2 As shown, each electrode 20 corresponds to two natural gas burners 300, which are arranged opposite each other so that the flames of the two natural gas burners 300 completely surround the baking area of ​​the electrode 20. The natural gas flow rate of the natural gas burners 300 is 20-50 standard cubic meters per hour, the pressure is 3-5 kilograms, the length of the natural gas burners 300 is 1-1.5 meters, and the flame length after ignition is 3-4 meters. This facilitates the baking of the electrode 20.

[0074] Optionally, the length of the calcination zone is 1200-1600 mm. In step S2, the electrode 20 is calcined and formed after a blue flame appears on the shell of the electrode 20 within the calcination zone. This facilitates control of the size of the calcination zone and ensures the timing of the electrode 20's calcination formation.

[0075] Furthermore, in step S2, the calcination process of electrode 20 can be as shown in the table below:

[0076]

[0077]

[0078] More specifically, in step S3, the water quenched slag is dry water quenched slag with water content less than 1%, and the depth of the water quenched slag layer 400 is 800-1200mm. The copper content in the water quenched slag is less than 0.2%, the iron / silica content is greater than 1.4%, and the sulfur content is less than 0.2%. In this way, the water quenched slag layer 400 has a reasonable size and low water content, which further facilitates the extension of the service life of the furnace lining.

[0079] Figures 1-3 A method for starting up a depletion furnace according to some examples of the present application is shown. As shown in Figures 1-3 Step S4 includes:

[0080] A pit is dug on the surface of the water quenched slag layer 400, and an arc striking device 500 is installed in the pit. The length of the pit is 1000-1200mm, the width is 500-700mm, and the depth is 900-1100mm. In this way, the installation of the arc striking device 500 is facilitated, and the heating effect of the electrode 20 after striking the arc is improved.

[0081] Optionally, step S4 further includes placing a wooden baffle on the side wall of the pit to prevent the water quenched slag on the side wall of the pit from sliding off. In this way, the water quenched slag on the side wall of the pit does not interfere with the installation process of the arc striking device 500 during the installation of the arc striking device 500. Moreover, the wooden baffle can remain in the furnace after the installation of the arc striking device 500 without the need for disassembly.

[0082] Specifically, as shown in Figure 1 and Figure 2 The arc striking device 500 includes an upper coke layer 510, a lower coke layer 520, and a steel mesh 530. The steel mesh 530 is sandwiched between the upper coke layer 510 and the lower coke layer 520. The steel mesh 530 includes a plurality of lower steel bars arranged in parallel and spaced apart, and a plurality of upper steel bars arranged in parallel and spaced apart. The upper steel bars and the lower steel bars are perpendicular to each other. Step S4 further includes the following steps:

[0083] Laying a lower coke layer 520 with a thickness of 400-600mm in the pit;

[0084] Laying a plurality of lower steel bars on the lower coke layer 520. The lower steel bars are oriented along the length direction of the pit;

[0085] Laying a plurality of upper steel bars above the lower steel bars. The upper steel bars are oriented along the width direction of the pit. The contact positions of the upper steel bars and the lower steel bars are welded to form the steel mesh 530;

[0086] Laying an upper coke layer 510 with a thickness of 200-400mm above the steel mesh 530.

[0087] Specifically, the lower steel bars can be hexagonal steel with a diameter of 20-35 mm, and the lower steel bars are 8-16 in number and each has a length of 10-12 m, and after being arranged, the lower steel bars form a lower layer of steel bars with a length of 10-12 m and a width of 2 m, and the upper steel bars are angle steel with a length of 2 m and a width of 25 mm.

[0088] In this way, the arc striking device 500 can be conveniently formed, and the installation of the arc striking device 500 can be facilitated.

[0089] Specifically, the electrodes 20 can be multiple and connected with the power supply short net system 21 above, so as to facilitate the electrode heating. Here, the electrodes 20 are preferably three and correspond to the 6 natural gas burners 300 and the 6 observation holes.

[0090] More specifically, the step S5 comprises:

[0091] The vertical distance between the electrodes 20 and the arc striking device 500 is 100-200 mm;

[0092] The electrodes 20 are powered, and the power supply amount is 3000-5000 kilovolt-ampere;

[0093] The electrodes 20 are lowered at a speed of 0.5-1 m / min;

[0094] An arc is formed between the electrodes 20 and the arc striking device 500, and the arc striking is successful.

[0095] In this way, the arc striking between the electrodes 20 and the arc striking device 500 can be facilitated.

[0096] Alternatively, the isolation layer 200 is a 2-3 mm thick stainless steel plate, which is laid on the bottom of the furnace body 10 and has a turned-up edge extending upward along the peripheral wall of the furnace body 10, the turned-up edge is tightly attached to the peripheral wall of the furnace body 10, and the height of the turned-up edge is 500-1000 mm. In this way, the sundries can be prevented from entering the brick joints.

[0097] Specifically, in the step S6, the melt depth is preferably 1800 mm. The furnace lining life can be further prolonged.

[0098] The method for starting up the depletion electric furnace according to some specific embodiments of the present application will be described below with reference to the accompanying drawings. Figures 1-3 The method for starting up the depletion electric furnace according to some specific embodiments of the present application will be described below with reference to the accompanying drawings.

[0099] After the brickwork of the furnace brick 100 of the depletion electric furnace is completed, a layer of stainless steel plate is laid on the furnace bottom, and a turned-up edge around the stainless steel plate has a height of 600 mm;

[0100] Six natural gas burners 300 are installed in six observation holes respectively, two burners correspond to one electrode 20, the length of the natural gas burners 300 into the furnace is greater than 1200mm, ignition is performed by using an electromagnetic igniter, the natural gas flow of each natural gas burner 300 is 50 standard cubic meters per hour, the pressure is 4kg, and the flame length is 4 meters, the length of the natural gas burner 300 is 1.2 meters;

[0101] The descending electrode 20 is subjected to electrode baking, and the electrode baking length is controlled to be 1600mm. After the electrode 20 shell appears blue flame in the range, the electrode baking is completed, and the natural gas burner 300 is turned off.

[0102] Dry water-quenched slag is added from the top of the lean electric furnace 1 to lay the furnace bottom, the water content of the water-quenched slag is less than 1%, the copper content is less than 0.2%, the iron / silicon dioxide content is greater than 1.4%, and the sulfur content is less than 0.2%. The water-quenched slag is uniformly laid on the furnace bottom with a thickness of 1200mm.

[0103] A 600mm wide and 1100mm long pit is dug below each of the three electrodes 20, and a wooden baffle is made. The arc striking device 500 is filled in the pit. The coke and round steel filling sequence of the arc striking device 500 is as follows: first, fill 500mm of lower coke layer 520 in the pit and flatten it, then lay 12 pieces of 11m long and 25mm diameter hexagonal steel on the lower coke layer 520, weld the laid steel bars to form a steel mesh 530 with 2m long and 25mm wide angle steel below the three electrodes 20, and connect the steel bars between the electrodes 20 with a small amount of steel bars. Lay another 300mm of upper coke layer 510 on the steel mesh 530 and flatten it.

[0104] Adjust the three electrodes 20 to be at the same height, with a vertical distance of 150mm from the arc striking device 500, and start the arc striking by supplying power to the electrodes 20. The power supply is 4000kVA, and the three electrodes 20 are slowly lowered at a speed control range of 0.8m / min. Strong arc light can be clearly seen in the electrode 20 observation hole, indicating successful arc striking.

[0105] Gradually increase the power of the electrodes 20 to 5000kVA to start heating and melting the dry water-quenched slag. The furnace brick temperature / time control data during the heating process is shown in the following table:

[0106] Temperature range (°C) Maximum heating rate (°C / h) Time required (h) Cumulative time (h) Room temperature - 150 5 25 25 150 holding 0 72 97 150-250 10 10 107 250 holding 0 48 155 250-350 10 10 165 350 holding 0 48 213 350-450 15 10 223 450 holding 0 36 259 450-600 15 10 269 600 holding 0 12 281 600-1200 20 30 321

[0107] According to the melting condition of the water-quenched slag in the furnace, dry water-quenched slag is added from the six charging holes at the top of the furnace. When the melt liquid level reaches 1800mm, the lean electric furnace 1 is turned off, and the power of the electrodes 20 is controlled to be in the range of 6000kVA. During this period, the furnace brick 100 temperature, the position of the furnace body steel shell expansion indicator, and the inlet and outlet water temperature of the furnace body cooling water are continuously recorded to guide the end of the furnace start-up and enter the production stage.

[0108] The embodiment of the present application uses natural gas as fuel to bake the electrode 20, the baking process is short and does not pollute the environment; the heating process of the furnace brick is scientific and reasonable, the thickness of the slag layer is moderate, and the service life of the furnace lining is greatly prolonged, compared with the previous rapid start-up method, the service life of the furnace lining is prolonged by 2-3 times, and the production cost of the enterprise is greatly reduced.

[0109] Other configurations and operations of the start-up method of the lean electric furnace according to the embodiment of the present application are known to those skilled in the art, and will not be described in detail here.

[0110] In the description of the present specification, the description referring to the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the exemplary description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0111] Although the embodiments of the present application have been shown and described, those skilled in the art can understand that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the claims and their equivalents.

Claims

1. A method of starting up a poor furnace, characterized by, The lean-out electric furnace comprises a furnace body and electrodes, at least a part of the electrodes extends into the furnace body, and the method comprises the following steps: S1, after the furnace body is built with furnace bricks, an isolation layer is laid on the bottom of the furnace body; S2, a natural gas burner is installed on the furnace body, the natural gas burner is turned on and ignited, and the electrodes are baked by the flame of the natural gas burner; S3, after the electrodes are baked and formed, the natural gas burner is turned off, water-quenched slag is added into the furnace body and laid on the isolation layer to form a water-quenched slag layer; S4, an arc striking device is installed on the water-quenched slag layer; S5, the electrodes are powered to strike an arc to form an electric arc between the electrodes and the arc striking device; S6, after the arc striking is successful, the power of the electrodes is gradually increased to heat and melt the water-quenched slag, and the water-quenched slag is continuously added into the furnace until the depth of the melt in the furnace body reaches 1600-2000 mm, and the furnace is started, wherein, during the gradual increase of the power of the electrodes, the maximum temperature rise of the furnace bricks per hour is less than 25 degrees Celsius.

2. The blowtou method of a reducing furnace according to claim 1, characterized by, In step S6, the gradual increase of the power of the electrodes comprises the following steps: The furnace bricks are raised from room temperature to 150 degrees Celsius at a speed of 0-5 degrees Celsius per hour within 20-30 hours, and are kept at 150 degrees Celsius for 70-75 hours; The furnace bricks are raised from 150 degrees Celsius to 250 degrees Celsius at a speed of 5-10 degrees Celsius per hour within 8-12 hours, and are kept at 250 degrees Celsius for 45-55 hours; The furnace bricks are raised from 250 degrees Celsius to 350 degrees Celsius at a speed of 5-10 degrees Celsius per hour within 8-12 hours, and are kept at 350 degrees Celsius for 45-55 hours; The furnace bricks are raised from 350 degrees Celsius to 450 degrees Celsius at a speed of 10-15 degrees Celsius per hour within 8-12 hours, and are kept at 450 degrees Celsius for 30-40 hours; The furnace bricks are raised from 450 degrees Celsius to 600 degrees Celsius at a speed of 10-15 degrees Celsius per hour within 8-12 hours, and are kept at 600 degrees Celsius for 10-15 hours; The furnace bricks are raised from 600 degrees Celsius to 1200 degrees Celsius at a speed of 15-25 degrees Celsius per hour within 25-35 hours.

3. The blowtou method of a reducing furnace according to claim 1, characterized by, The furnace body is provided with an observation hole, and the natural gas burners are installed in the observation hole in step S2, and each electrode corresponds to a plurality of natural gas burners so that the flames of the plurality of natural gas burners completely surround the baking area of the electrodes.

4. The blowtou method of a reducing furnace according to claim 1, characterized by, The length of the baking area is 1200-1600 mm, and the electrodes are baked and formed after the shell of the electrodes in the baking area appears blue flame in step S2.

5. The blowtou method of a reducing furnace according to claim 1, characterized by, In step S3, the water-quenched slag is dry water-quenched slag with a water content of less than 1%, and the depth of the water-quenched slag layer is 800-1200 mm.

6. The blowtou method of a reducing furnace according to claim 1, characterized by, The step S4 comprises: A pit is dug on the surface of the water-quenched slag layer, and the arc striking device is installed in the pit, the length of the pit is 1000-1200 mm, the width is 500-700 mm, and the depth is 900-1100 mm.

7. The blowtou method of a reducing furnace according to claim 6, characterized by, The step S4 further comprises: Wooden baffles are placed on the side walls of the pit to prevent the water-quenched slag on the side walls of the pit from sliding down.

8. The blowtou method of a reducing furnace according to claim 6, characterized by, The arc striking device comprises an upper coke layer, a lower coke layer and a steel mesh, the steel mesh is clamped between the upper coke layer and the lower coke layer, the steel mesh comprises a plurality of lower steels arranged in parallel and a plurality of upper steels arranged in parallel, the upper steels and the lower steels are perpendicular to each other, and the step S4 further comprises the following steps: Laying the lower coke layer with a thickness of 400-600 mm in the pit; Laying a plurality of the lower steels on the lower coke layer, the lower steels are oriented along the length direction of the pit; Laying a plurality of the upper steels above the lower steels, the upper steels are oriented along the width direction of the pit, and the contact positions of the upper steels and the lower steels are welded to form the steel mesh; Laying the upper coke layer with a thickness of 200-400 mm above the steel mesh.

9. The blowtou method of a reducing furnace according to claim 1, characterized by, The step S5 comprises: The vertical distance between the electrode and the arc striking device is 100-200 mm; The electrode is powered with a power of 3000-5000 kilovolt-ampere; The electrode is lowered at a speed of 0.5-1 m / min; An arc is formed between the electrode and the arc striking device, and the arc striking is successful.

10. The blowtou method of a reducing furnace according to claim 1, characterized by, The isolation layer is a stainless steel plate with a thickness of 2-3 mm, the stainless steel plate covers the bottom of the furnace body and has a flange extending upward along the circumferential wall of the furnace body, the flange is tightly fitted with the circumferential wall of the furnace body, and the flange is 500-1000 mm high.

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