Preparation method for producing electrode by utilizing Acheson graphitization furnace

Abstract

The invention discloses a preparation method for producing an electrode by utilizing an Acheson graphitization furnace. The preparation method comprises the following steps: preparing a carbon electrode, loading the carbon electrode into the graphitization furnace, carrying out graphitization power transmission, cooling, discharging from the furnace, machining and the like. According to the method, the Acheson graphitization furnace is used for carrying out graphitization treatment on the carbon electrode, in the treatment process, the comprehensive energy consumption of each ton of main products (graphite electrodes) and by-products (calcined coke and the like) is about 2400-2600 kilowatt-hour, the energy consumption is greatly reduced compared with that in the prior art, and the electrode graphitization treatment cost can be effectively reduced.

Description

Technical Field

[0001] The invention relates to the technical field of graphite electrode production, and in particular to a preparation method for producing electrodes by utilizing an Acheson graphitization furnace. Background Art

[0002] Graphite electrode is a high temperature resistant graphite conductive material made through multiple processes with petroleum coke, asphalt coke and other materials as aggregates and coal tar as binder. Its main uses include electric furnace steelmaking, electric arc furnace, resistance furnace, hot die casting mold and vacuum furnace heating element and other special products. Graphite electrode is a conductor that releases electric energy in the form of arc in electric arc furnace to heat and melt the charge, especially in the fields of metallurgy, chemical industry, electric power, semiconductor, etc. As a conductor for electron transmission, it plays a key role in the reaction of electric arc furnace, and can also withstand extreme environments such as high temperature and high pressure.

[0003] In the production of graphite electrodes, graphitization treatment is a key process, which affects the physical and chemical properties of graphite electrodes, such as thermal conductivity, electrical conductivity, wear resistance, thermal stability, thermal shock resistance and chemical stability. The physical and chemical properties of graphite electrodes are largely determined by the graphitization temperature, which should be above 2500°C. At present, the production of graphite electrodes generally relies on internal series graphitization furnaces. For example, in the patent application number CN201810431358.8, entitled A New Graphite Electrode Production Process, the electrode is graphitized using an internal heat series (LWG) furnace.

[0004] However, when the inner string graphitization furnace is used, a huge amount of electric energy needs to be input to heat the product to the high temperature stage required for the graphitization process, resulting in huge energy consumption of the inner string graphitization furnace. According to the content recorded in the "Research on the Process of Inner String Graphitization Furnace", it is stated that for every ton of graphite electrode produced, the energy consumption is as high as 3200 kWh of electricity. At the same time, the loading capacity of this type of single furnace is relatively limited, and it can usually only accommodate about 20 electrodes. Taking the standard 1272 mm electrode as an example, its length extends to 2700 mm, and the weight of a single electrode reaches about 5.6 tons. It is further calculated that the total weight of the electrodes in the whole furnace is about 112 tons, and because the insulation layer of the inner string furnace is relatively thin, it is easy to cause oxidation of the product, reducing the product qualification rate. As a result, the inner string graphitization furnace has problems such as high energy consumption, low loading capacity of the whole furnace electrode, and inability to achieve batch processing of large-volume graphite electrodes in the graphitization process of carbon electrodes. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a method for producing electrodes using an Acheson graphitization furnace. By performing graphitization treatment through reasonable filling steps, the energy consumption of graphitization treatment per ton of graphite electrode can be effectively reduced, which is beneficial to batch graphitization treatment of graphite electrodes.

[0006] To achieve the above object, the present invention adopts the following technical solution: a method for producing an electrode using an Acheson graphitization furnace, comprising the following steps:

[0007] (1) Preparation of carbon electrodes;

[0008] (2) Loading carbon electrodes into graphitization furnace:

[0009] 1) Using an Acheson graphitization furnace, filling the bottom of the Acheson graphitization furnace with carbon black, flattening and compacting it to form a carbon black layer;

[0010] 2) Using two furnace core plates arranged at intervals, the space above the carbon black layer in the furnace is divided into a furnace core area and two furnace wall insulation material areas;

[0011] 3) In the furnace core area, two layers of calcined coke are laid and leveled at the bottom, carbon electrodes are placed on the calcined coke, a layer of resistor material is laid above the carbon electrodes, multiple air holes are arranged above the resistor material using pipe fittings, the air holes are filled with calcined coke, and insulation material is filled around the air holes;

[0012] 4) Fill the insulation material in the two furnace wall insulation material areas respectively, flatten and compact them, and the thickness of the insulation material should be greater than or equal to 1000mm;

[0013] 5) After loading is completed, remove the furnace core plate and pipe fittings;

[0014] Among them, the diameter range of carbon electrodes is φ800-φ1400mm;

[0015] (3) Graphitization power supply: Acheson graphitization furnace supplies power to graphitize the carbon electrode;

[0016] (4) Cooling and taking out of the furnace to obtain a graphite electrode blank;

[0017] (5) Mechanically processing the graphite electrode blank to obtain a graphite electrode finished product of a preset size.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present application utilizes an Acheson graphitization furnace to graphitize carbon electrodes. During the treatment process, the combined energy consumption of each ton of the main product (graphite electrode) and the by-product (calcined coke) is approximately 2400 to 2600 kilowatt-hours of electricity, which is significantly lower than that in the prior art and can effectively reduce the cost of electrode graphitization treatment.

[0020] Secondly, the processing method of the present application can ensure that the carbon electrode undergoes high-temperature graphitization treatment, which can not only improve the thermal conductivity and electrical conductivity of the electrode, but also improve the wear resistance of the electrode, and can also improve the thermal stability, heat shock resistance and chemical stability of the electrode.

[0021] In addition, depending on the charging method adopted, the charging capacity of the electrode can reach about 300 tons. If the various by-products filled inside the electrode are taken into account, the weight of the overall material can rise to about 450 tons. When the electrode is finished, the calcined coke, which is a key by-product, can be converted into graphitized coke with excellent performance after high-temperature graphitization. It is worth mentioning that this graphitized coke with outstanding performance can also be widely used in many fields such as carbon electrode manufacturing, thus building an efficient and sustainable virtuous cycle system, thereby saving costs and creating huge economic value.

[0022] Furthermore, in step 3), the two layers of calcined coke include, from bottom to top, a type of calcined coke with a particle size range of 0-2 mm and a type of calcined coke with a particle size range of 8-25 mm.

[0023] Furthermore, in step 3), the carbon electrode is divided into two layers, the upper and lower layers, the carbon electrodes of each layer are laid horizontally side by side, and the second type of calcined coke is filled between the two layers of carbon electrodes.

[0024] Furthermore, the thickness of the second type calcined coke filled between the two layers of carbon electrodes is 150 mm.

[0025] Furthermore, the resistivity of the carbon electrode is 35-38 μΩ·m, and the flexural strength is not less than 7.0 MPa.

[0026] Furthermore, the thermal insulation material in step 3) and step 4) has a resistivity of 400-600 μΩ·m, an ash content of no more than 0.5%, and a volatile content of no more than 0.5%.

[0027] Furthermore, in step (3), the Acheson graphitization furnace supplies electricity, and its starting power is 4000-5000KW, the rising power is 600-1000KW, and the power supply time is 70-75 hours. After reaching the maximum power of 25,000 kW, the power supply is maintained for 10-15 hours, and the power supply is stopped. The total power supply is 1.05-1.15 million KWH.

[0028] Further, in step (4), the auxiliary materials are cleaned 48 hours after the Acheson graphitization furnace is powered off, with the first cleaning depth of 80-100 mm. The subsequent cleaning will repeat the following steps:

[0029] After the surface temperature of the auxiliary material has cooled naturally for 72-96 hours, clean the auxiliary material of 80-100mm again.

[0030] Furthermore, the diameter of the carbon electrode is φ1272 mm.

[0031] Furthermore, the width of the furnace core area is 3030-3300 mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the partition structure of the furnace core area and the furnace wall insulation material area in the Acheson graphitization furnace of the present invention;

[0033] Figure 2 This is a schematic diagram of the structural distribution of each filler layer after the Acheson graphitization furnace of the present invention is completed with carbon electrodes. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0035] The present invention provides a method for producing an electrode using an Acheson graphitization furnace, comprising the following steps:

[0036] 1. Preparation of carbon electrode, including the following steps:

[0037] Step 1: Pre-crushing and medium-crushing grinding: large pieces of raw materials such as graphitized coke, turning pieces, roasting pieces, etc. are mechanically crushed and ground into granular materials or powders.

[0038] Step 2: Mixing: Weigh and mix various crushed granules and powders according to the following weight ratios;

[0039]

[0040] Step 3, heating and kneading: preheat the kneading pot to 180°C, add the materials with the above proportions into the kneading pot under normal pressure and heat to 140-150°C, dry mix for 65-75 minutes, drain the water in the materials, and then add 20.5% modified coal tar that has been completely melted and fully allowed to stand at a temperature of 165°C, wet mix for 25-40 minutes, remove from the pot in a paste state, and discharge into the hopper.

[0041] Step 4, drying the material: put the paste in the hopper into a preheated drying mixing drum with a temperature stabilized at 145-155°C. After 15 minutes of stirring and drying, most of the asphalt fume in the paste is discharged. When the paste temperature reaches 140°C, put it into a weighing device for weighing.

[0042] Step 5, molding: weigh the specified weight and put it into the mold. The mold temperature is 95-110℃, and the paste temperature is 135-150℃. The upper part is pressurized by a hydraulic cylinder, and the lower part is vibrated by an eccentric block vibration device to maintain high-speed vibration. The vibration time is ≥360s, and the volume density is ≥1.70g / cm 3 , to obtain the raw product.

[0043] Step six, roasting: use a ring roasting furnace, lay metallurgical coke particles on the bottom of the ring roasting furnace, load the carbon electrode green body into the ring roasting furnace, fill the gaps with metallurgical coke particles, and tamp them down. In the air-tight condition, heat treatment is carried out at a predetermined curve heating rate for a total of 768 hours. After the heating treatment, a qualified roasted product is obtained, namely the carbon electrode.

[0044] In the present application, the resistivity of the carbon electrode is 35-38 μΩ·m, and the flexural strength is not less than 7.0 Mpa.

[0045] 2. Reference Figure 1 , Figure 2 The structure shown is used to load the carbon electrode into the graphitization furnace:

[0046] 1) Use Acheson graphitization furnace, such as Figure 1 As shown, the furnace body 100 of the Acheson graphitization furnace is a rectangular structure with an open upper end, including furnace walls 101 on the upper and lower sides and conductive walls 102 on the left and right ends. A plurality of powered electrodes are provided on the conductive walls 102. Those skilled in the art refer to the sides where the two conductive walls 102 are located as the front and rear sides of the furnace body 100, and the sides where the two furnace walls are located as the left and right sides of the furnace body 100.

[0047] According to the structural characteristics of the Acheson graphitization furnace, carbon black is filled at the bottom of the Acheson graphitization furnace, flattened and compacted to form a Figure 2 The carbon black layer 210 is shown in the position shown. The carbon black index requirements are: powder resistivity ≥ 1800 μΩ·m, ash content ≤ 0.5%, and volatile matter ≤ 0.8%.

[0048] 2)Reference Figure 1 , using two furnace core plates 140 arranged at intervals, the space in the furnace above the carbon black layer 210 is divided into a furnace core area 120 and two furnace wall insulation material areas 110, wherein the area where the dotted line in the middle of the furnace core area 120 is located is the carbon electrode product loading area 130, the distance A represents the distance between the carbon electrode product and the furnace head conductive wall, and the distance B represents the width of the furnace core area 120.

[0049] 3) Based on Figure 1The structure is such that in the furnace core area 120, two layers of calcined coke are laid and leveled at the bottom, wherein the two layers of calcined coke include, from bottom to top, a type I calcined coke 220 with a particle size range of 0-2mm and a type II calcined coke 240 with a particle size range of 8-25mm. A carbon electrode 250 is loaded on the type II calcined coke 240, and the diameter of the carbon electrode ranges from φ800 to φ1400mm. In the present application, the carbon electrode is composed of two layers, upper and lower, and the carbon electrodes of each layer are laid horizontally side by side, and type II calcined coke 211 is loaded between the two layers of carbon electrodes, and the thickness of type II calcined coke is 150mm. A layer of resistor material is laid above the carbon electrode, and the resistor material consists of two layers of structure laid up and down, the lower structure 260 is made of type II calcined coke, and the upper structure 270 is made of alternative coke. A plurality of air holes are arranged above the resistor material by using a through pipe. The through pipe is a cylindrical structure of a specific size. The through pipe is vertically arranged, and the lower end is in contact with the second type of calcined coke of the resistor material. The calcined coke 280 is filled in the air holes (inside the through pipe), and the surrounding of the air holes (outside the through pipe) is filled with insulation material 290. The insulation layer covers all areas above the resistor material. Among them, the index requirements of calcined coke are: calcined coke powder resistivity 480-550μΩ·m, ash content ≤0.5%, volatile matter ≤0.5%.

[0050] 4) Fill the insulation material in the two furnace wall insulation material areas respectively, flatten and compact them, and the thickness of the insulation material should be greater than or equal to 1000mm.

[0051] The thermal insulation material in step 3) and step 4) has a resistivity of 400-600 μΩ·m, an ash content of no more than 0.5%, and a volatile content of no more than 0.5%.

[0052] 5) After loading is completed, remove the furnace core plate and pipe fittings.

[0053] 3. Power supply for graphitization: The Acheson graphitization furnace supplies power with a starting power of 4000-5000KW, an increasing power of 600-1000KW, and a power supply time of 70-75 hours. After reaching the maximum power of 25,000 kW, the power supply is maintained for 10-15 hours and then stopped. The total power supply is 1.05-1.15 million KWH.

[0054] 4. Cooling and taking out of the furnace to obtain graphite electrode blank;

[0055] Specifically, the auxiliary materials are cleaned 48 hours after the Acheson graphitization furnace is powered off. The first cleaning depth is 80-100mm. The subsequent cleaning will repeat the following steps: After the surface temperature of the auxiliary materials cools naturally for 72-96 hours, the auxiliary materials of 80-100mm are cleaned again. The specific processing process is shown in Table 1.

[0056] Table 1:

[0057]

[0058]

[0059] Among them, the cleaning of auxiliary materials began 48 hours after the power outage, and was divided into multiple cleanings according to the situation. Single cleaning was carried out by manual cooperation with mechanical equipment, and the depth of each cleaning was 80-100mm. When cleaning, iron rakes and other tools were used to grab the auxiliary materials to both sides of the furnace wall, and then a small flat grab carried by a crane was used to grab the auxiliary materials from both sides of the furnace wall.

[0060] 5. Machining the graphite electrode blank to obtain a graphite electrode product of preset size.

[0061] In Examples 1-4, the size of the carbon electrode to be processed is φ1272 mm as an example, and the Acheson graphitization furnace used is 39.2 meters long, 5.6 meters wide, and 5.2 meters deep, which is used to demonstrate the graphite electrode preparation method of the present application.

[0062] Example 1

[0063] A method for producing an electrode using an Acheson graphitization furnace comprises the following steps:

[0064] 1. Preparation of carbon electrode, including the following steps:

[0065] Step 1: Pre-crushing and medium-crushing grinding: large pieces of raw materials such as graphitized coke, turning pieces, roasting pieces, etc. are mechanically crushed and ground into granular materials or powders.

[0066] Step 2: Mixing: Weigh and mix various crushed granules and powders according to the following weight ratios;

[0067]

[0068]

[0069] Step 3, heating and kneading: preheat the kneading pot to 180°C, add the materials with the above proportions into the kneading pot under normal pressure and heat to 140-150°C, dry mix for 65-75 minutes, drain the water in the materials, and then add 20.5% modified coal tar that has been completely melted and fully allowed to stand at a temperature of 165°C, wet mix for 25-40 minutes, remove from the pot in a paste state, and discharge into the hopper.

[0070] Step 4, drying the material: put the paste in the hopper into a preheated drying mixing drum with a temperature stabilized at 145-155°C. After 15 minutes of stirring and drying, most of the asphalt fume in the paste is discharged. When the paste temperature reaches 140°C, put it into a weighing device for weighing.

[0071] Step 5, molding: weigh the specified weight and put it into the mold. The mold temperature is 95-110℃, and the paste temperature is 135-150℃. The upper part is pressurized by a hydraulic cylinder, and the lower part is vibrated by an eccentric block vibration device to maintain high-speed vibration. The vibration time is ≥360s, and the volume density is ≥1.70g / cm 3 , to obtain the raw product.

[0072] Step six, roasting: use a ring roasting furnace, lay metallurgical coke particles on the bottom of the ring roasting furnace, load the carbon electrode green body into the ring roasting furnace, fill the gaps with metallurgical coke particles, and tamp them down. In the air-tight condition, heat treatment is carried out at a predetermined curve heating rate for a total of 768 hours. After the heating treatment, a qualified roasted product is obtained, namely the carbon electrode.

[0073] In the present application, the resistivity of the carbon electrode is 35-38 μΩ·m, and the flexural strength is not less than 7.0 Mpa.

[0074] 2. Loading carbon electrodes into graphitization furnace:

[0075] 1) Using an Acheson graphitization furnace, fill the bottom of the Acheson graphitization furnace with carbon black, flatten and compact it to form a carbon black layer.

[0076] 2) The space above the carbon black layer in the furnace is divided into a furnace core area and two furnace wall insulation material areas by using two furnace core plates arranged at intervals, wherein the width of the furnace core area is 3030 mm.

[0077] 3) In the furnace core area, two layers of calcined coke are laid and leveled on the bottom, wherein the two layers of calcined coke include, from bottom to top, a type of calcined coke with a particle size range of 0-2 mm and a type of calcined coke with a particle size range of 8-25 mm, the laying thickness of the type one calcined coke is 150 mm, and the laying thickness of the type two calcined coke is 250 mm.

[0078] The carbon electrode is placed on the second-class calcined coke. The carbon electrode is in two layers, and each layer of carbon electrode is laid horizontally side by side. The second-class calcined coke is placed between the two layers of carbon electrodes and compacted. The thickness of the second-class calcined coke is 150mm. The distance between the carbon electrode product and the conductive wall of the furnace head is 1000mm.

[0079] A layer of resistor material is laid on top of the carbon electrode. The resistor material consists of two layers, the lower structure is made of 150mm thick second-class calcined coke, and the upper structure is made of 200mm thick substitute coke. The substitute coke is calcined coke with a particle size range of 2-8mm.

[0080] A plurality of air holes are arranged above the resistor material by using a through pipe fitting. The through pipe fitting is a cylindrical structure of a specific size. The through pipe fitting is vertically arranged with its lower end in contact with the second type of calcined coke of the resistor material. The air holes (inside the through pipe fitting) are filled with calcined coke, and a 400mm thick insulation material layer is filled around the air holes (outside the through pipe fitting). The insulation material layer covers all areas above the resistor material.

[0081] 4) Fill the insulation material in the two furnace wall insulation material areas respectively, flatten and compact them, and the thickness of the insulation material should be greater than or equal to 1000mm.

[0082] The thermal insulation material in step 3) and step 4) has a resistivity of 400-600 μΩ·m, an ash content of no more than 0.5%, and a volatile content of no more than 0.5%.

[0083] 5) After loading is completed, remove the furnace core plate and pipe fittings.

[0084] 3. Power supply for graphitization: The Acheson graphitization furnace supplies power with a starting power of 4000-5000KW, an increasing power of 600-1000KW, and a power supply time of 70-75 hours. After reaching the maximum power of 25,000 kW, the power supply is maintained for 10-15 hours and then stopped. The total power supply is 1.05-1.15 million KWH.

[0085] 4. Cooling and taking out of the furnace to obtain graphite electrode blank;

[0086] Specifically, the auxiliary materials are cleaned 48 hours after the Acheson graphitization furnace is powered off. The first cleaning depth is 80-100mm. The subsequent cleaning will repeat the following steps: After the surface temperature of the auxiliary materials cools down naturally for 72-96 hours, the auxiliary materials of 80-100mm are cleaned again. The specific processing process is shown in Table 2.

[0087] Table 2:

[0088] Number of cleaning times Cleaning interval time (H) After a power outage Cleaning depth (mm) 1 48 80-100 2 72-96 120-144 80-100 3 72-96 192-240 80-100 4 72-96 264-336 80-100 5 72-96 336-432 80-100 6 72-96 408-528 80-100 7 72-96 480-624 80-100 8 72-96 552-720 80-100 9 72-96 624-816 80-100

[0089] Among them, the cleaning of auxiliary materials began 48 hours after the power outage, and was divided into multiple cleanings according to the situation. Single cleaning was carried out by manual cooperation with mechanical equipment, and the depth of each cleaning was 80-100mm. When cleaning, iron rakes and other tools were used to grab the auxiliary materials to both sides of the furnace wall, and then a small flat grab carried by a crane was used to grab the auxiliary materials from both sides of the furnace wall.

[0090] 5. Machining the graphite electrode blank to obtain a graphite electrode product of preset size.

[0091] Example 2

[0092] The difference between this embodiment and embodiment 1 is that:

[0093] 2) The space above the carbon black layer in the furnace is divided into a furnace core area and two furnace wall insulation material areas by using two furnace core plates arranged at intervals, wherein the width of the furnace core area is 3200 mm.

[0094] 3) In the furnace core area, two layers of calcined coke are laid and leveled on the bottom, wherein the two layers of calcined coke include, from bottom to top, a type of calcined coke with a particle size range of 0-2 mm and a type of calcined coke with a particle size range of 8-25 mm, the laying thickness of the type one calcined coke is 100 mm, and the laying thickness of the type two calcined coke is 300 mm.

[0095] The carbon electrode is placed on the second-class calcined coke. The carbon electrode is in two layers, and each layer of carbon electrode is laid horizontally side by side. The second-class calcined coke is placed between the two layers of carbon electrodes and compacted. The thickness of the second-class calcined coke is 150mm. The distance between the carbon electrode product and the conductive wall of the furnace head is 1000mm.

[0096] A layer of resistor material is laid on top of the carbon electrode. The resistor material consists of two layers, the lower structure is made of 150mm thick second-class calcined coke, and the upper structure is made of 80mm thick substitute coke. The substitute coke is calcined coke with a particle size range of 2-8mm.

[0097] A plurality of air holes are arranged above the resistor material by using a through pipe fitting. The through pipe fitting is a cylindrical structure of a specific size. The through pipe fitting is vertically arranged with its lower end in contact with the second type of calcined coke of the resistor material. The air holes (inside the through pipe fitting) are filled with calcined coke, and a 600mm thick insulation material layer is filled around the air holes (outside the through pipe fitting). The insulation material layer covers all areas above the resistor material.

[0098] Example 3

[0099] The difference between this embodiment and embodiment 1 is that:

[0100] 2) The space above the carbon black layer in the furnace is divided into a furnace core area and two furnace wall insulation material areas by using two furnace core plates arranged at intervals, wherein the width of the furnace core area is 3300 mm.

[0101] 3) In the furnace core area, two layers of calcined coke are laid and leveled on the bottom, wherein the two layers of calcined coke include, from bottom to top, a type of calcined coke with a particle size range of 0-2 mm and a type of calcined coke with a particle size range of 8-25 mm, the laying thickness of the type one calcined coke is 100 mm, and the laying thickness of the type two calcined coke is 300 mm.

[0102] The carbon electrode is placed on the second-class calcined coke. The carbon electrode is in two layers, and each layer of carbon electrode is laid horizontally side by side. The second-class calcined coke is placed between the two layers of carbon electrodes and compacted. The thickness of the second-class calcined coke is 150mm. The distance between the carbon electrode product and the conductive wall of the furnace head is 1000mm.

[0103] A layer of resistor material is laid on top of the carbon electrode. The resistor material consists of two layers, the lower structure is made of 150mm thick second-class calcined coke, and the upper structure is made of 200mm thick substitute coke. The substitute coke is calcined coke with a particle size range of 2-8mm.

[0104] A plurality of air holes are arranged above the resistor material by using a through pipe fitting. The through pipe fitting is a cylindrical structure of a specific size. The through pipe fitting is vertically arranged with its lower end in contact with the second type of calcined coke of the resistor material. The air holes (inside the through pipe fitting) are filled with calcined coke, and a 400mm thick insulation material layer is filled around the air holes (outside the through pipe fitting). The insulation material layer covers all areas above the resistor material.

[0105] Example 4

[0106] The difference between this embodiment and embodiment 1 is that:

[0107] 2) The space above the carbon black layer in the furnace is divided into a furnace core area and two furnace wall insulation material areas by using two furnace core plates arranged at intervals, wherein the width of the furnace core area is 3300 mm.

[0108] 3) In the furnace core area, two layers of calcined coke are laid and leveled on the bottom, wherein the two layers of calcined coke include, from bottom to top, Class I calcined coke with a particle size range of 0-2 mm and Class II calcined coke with a particle size range of 8-25 mm, the laying thickness of Class I calcined coke is 150 mm, and the laying thickness of Class II calcined coke is 150 mm.

[0109] The carbon electrode is placed on the second-class calcined coke. The carbon electrode is in two layers, and each layer of carbon electrode is laid horizontally side by side. The second-class calcined coke is placed between the two layers of carbon electrodes and compacted. The thickness of the second-class calcined coke is 150mm. The distance between the carbon electrode product and the conductive wall of the furnace head is 800mm.

[0110] A layer of resistor material is laid on top of the carbon electrode. The resistor material consists of two layers, the lower structure is made of 100mm thick Class II calcined coke, and the upper structure is made of 80mm thick substitute coke, which is calcined coke with a particle size range of 2-8mm.

[0111] A plurality of air holes are arranged above the resistor material by using a through pipe fitting. The through pipe fitting is a cylindrical structure of a specific size. The through pipe fitting is vertically arranged with its lower end in contact with the second type of calcined coke of the resistor material. The air holes (inside the through pipe fitting) are filled with calcined coke, and a 600mm thick insulation material layer is filled around the air holes (outside the through pipe fitting). The insulation material layer covers all areas above the resistor material.

[0112] Among them, in Examples 1-4, the specific parameters for graphitization power transmission operation are shown in Table 2:

[0113] Table 2:

[0114] Example Duration(H) Total power(KWH) Maximum power (kW) Maintenance time (H) 1 70 1.05 million 25,000 10 2 70 1.05 million 25,000 15 3 75 1.15 million 25,000 10 4 75 1.15 million 25,000 15

[0115] Some parameters and experimental results in the preparation process of the graphite electrode in Examples 1-4 were statistically analyzed to obtain the content shown in Table 3.

[0116] Table 3:

[0117] project Example 1 Example 2 Example 3 Example 4 Furnace core width (mm) 3030 3200 3300 3300 Thickness of calcined coke at the bottom of furnace (mm) 150 100 100 150 Thickness of the second type of calcined coke at the bottom of the furnace (mm) 250 300 300 150 Distance between carbon electrode and conductive wall (mm) 1000 1000 1000 800 Resistor material thickness (mm) 150 150 150 100 Alternative focal thickness (mm) 200 80 200 80 Thickness of insulation layer above replacement coke (mm) 400 600 400 600 Total weight of furnace (tons) 436 454 445 447 Resistivity(μΩm) 12.4 13.6 13.1 10.5 Unit consumption (kW·h / t) 2406 2309 2580 2567 Whether oxidation No oxidation No oxidation No oxidation No oxidation

[0118] It is worth noting that the above implementation is only an example display. In order to improve production efficiency, the implementation can be expanded and adjusted according to the volume of different furnaces. It can be set to a multi-layer or multi-row furnace loading method, including but not limited to the parameters in the above embodiments.

[0119] According to the data in Table 3, we can see that:

[0120] The resistivity of the graphite electrode prepared by the present application meets the use requirements, and there is no strong oxidation, indicating that the graphite electrode of the present application has good thermal conductivity and electrical conductivity.

[0121] At the same time, according to the unit consumption data, it can be seen that in the present application, when the electrode graphitization treatment is carried out, the maximum comprehensive energy consumption of each ton of the main product (graphite electrode) and the by-product (calcined coke) is only 2580 kWh, which is much lower than the energy consumption of -3200 kWh per ton of electrode in the internal string graphitization furnace in the prior art, which can greatly save energy consumption and reduce processing costs.

[0122] At the same time, according to the data of the total weight of the furnace, it can be seen that the present application uses the Acheson graphitization furnace to carry out graphitization treatment of electrodes, which can achieve single-time large-scale production and is also suitable for graphitization treatment of electrodes with larger sizes.

[0123] The present invention solves some of the shortcomings of the existing process and proposes a process for producing electrodes using an Acheson graphitization furnace. By graphitizing carbon electrodes at high temperature, it can not only save processing costs, but also improve thermal energy utilization efficiency, improve the thermal conductivity and electrical conductivity of the electrodes, and also improve the wear resistance of the electrodes, and also improve the thermal stability, heat shock resistance and chemical stability of the electrodes.

[0124] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A method for producing electrodes using an Acheson graphitization furnace, characterized in that: The steps include: (1) Preparation of carbon electrodes; (2) Loading carbon electrodes into graphitization furnace: 1) Using an Acheson graphitization furnace, filling the bottom of the Acheson graphitization furnace with carbon black, flattening and compacting it to form a carbon black layer; 2) Using two furnace core plates arranged at intervals, the space above the carbon black layer in the furnace is divided into a furnace core area and two furnace wall insulation material areas; 3) In the furnace core area, two layers of calcined coke are laid and leveled at the bottom, carbon electrodes are placed on the calcined coke, a layer of resistor material is laid above the carbon electrodes, multiple air holes are arranged above the resistor material using pipe fittings, the air holes are filled with calcined coke, and insulation material is filled around the air holes; 4) Fill the insulation material in the two furnace wall insulation material areas respectively, flatten and compact them, and the thickness of the insulation material should be greater than or equal to 1000mm; 5) After loading is completed, remove the furnace core plate and pipe fittings; Among them, the diameter range of carbon electrodes is φ800-φ1400mm; (3) Graphitization power supply: Acheson graphitization furnace supplies power to graphitize the carbon electrode; (4) Cooling and taking out of the furnace to obtain a graphite electrode blank; (5) Mechanically processing the graphite electrode blank to obtain a graphite electrode finished product of a preset size.

2. The method for producing electrodes using an Acheson graphitization furnace according to claim 1, characterized in that: In step 3), the two layers of calcined coke include, from bottom to top, a type of calcined coke with a particle size range of 0-2 mm and a type of calcined coke with a particle size range of 8-25 mm.

3. The method for producing electrodes using an Acheson graphitization furnace according to claim 2, characterized in that: In step 3), the carbon electrodes are divided into two layers, the upper and lower layers, the carbon electrodes of each layer are laid horizontally side by side, and the second type of calcined coke is filled between the two layers of carbon electrodes.

4. The method for producing electrodes using an Acheson graphitization furnace according to claim 3, characterized in that: The thickness of the second type calcined coke filled between the two layers of carbon electrodes is 150mm.

5. The method for producing an electrode using an Acheson graphitization furnace according to any one of claims 1 to 4, characterized in that: The resistivity of the carbon electrode is 35-38μΩ·m, and the flexural strength is not less than 7.0Mpa.

6. The method for producing electrodes using an Acheson graphitization furnace according to claim 5, characterized in that: The thermal insulation material in step 3) and step 4) has a resistivity of 400-600 μΩ·m, an ash content of no more than 0.5%, and a volatile content of no more than 0.5%.

7. The method for producing an electrode using an Acheson graphitization furnace according to any one of claims 1 to 4, characterized in that: In step (3), the Acheson graphitization furnace supplies electricity, with a starting power of 4000-5000KW, a rising power of 600-1000KW, and a power supply time of 70-75 hours. After reaching a maximum power of 25,000 kW, the power supply is maintained for 10-15 hours and then stopped. The total power supply is 1.05-1.15 million KWH.

8. The method for producing an electrode using an Acheson graphitization furnace according to any one of claims 1 to 4, characterized in that: In step (4), the auxiliary materials are cleaned 48 hours after the Acheson graphitization furnace is powered off. The first cleaning depth is 80-100 mm. The subsequent cleaning will repeat the following steps: After the surface temperature of the auxiliary material has cooled naturally for 72-96 hours, clean the auxiliary material of 80-100mm again.

9. The method for producing an electrode using an Acheson graphitization furnace according to any one of claims 1 to 4, characterized in that: The diameter of the carbon electrode is φ1272mm.

10. The method for producing electrodes using an Acheson graphitization furnace according to claim 9, characterized in that: The width of the furnace core area is 3030-3300mm.

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