Method for assisting blowing-in of side-blown converter by pyrite
By adding pyrite to the side-blown furnace to rapidly increase the temperature and dissolve the slag on the partition wall, the problem of prolonged hot shutdown caused by slag formation was solved, enabling rapid and stable furnace start-up and efficient production.
Patent Information
- Application Number
- CN202510966562.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-14
- Publication Date
- 2025-11-21
AI Technical Summary
During the shutdown period, prolonged hot shutdowns caused by slagging and other malfunctions in side-blown furnaces can lead to slagging on the partition walls that is difficult to melt, affecting the normal flow of molten slag. Furthermore, the risk of slagging again is high, and the partition walls cannot pass through the slag when directly fed into concentrate smelting, increasing economic losses and the consumption of manpower and material resources.
By partially or completely adding pyrite, the furnace temperature is rapidly increased, the slag on the partition wall is dissolved, and the normal flow of materials and heat in the furnace is achieved by cooperating with the low-level standby slag outlet, thus restoring the process parameters of the side-blown furnace.
This technology enables rapid increase in furnace temperature without raising the copper surface area, dissolving slag buildup on the partition walls, ensuring rapid and stable start-up of the side-blown furnace, reducing start-up time and manpower and material consumption, and improving smelting efficiency.
Smart Images
Figure CN120989401A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of metal smelting technology, and specifically relates to a method for starting up a pyrite auxiliary side-blown furnace. Background Technology
[0002] Side-blown furnaces are widely used in the smelting of metals such as lead, nickel, and copper. They have advantages such as low investment costs, simple supporting systems, no need for material drying, and the ability to process various complex ores. However, side-blown furnaces have high requirements for the precision of the charging and air supply systems, as well as the stability of the liquid level inside the furnace. They are particularly susceptible to prolonged shutdowns. In actual production, unpredictable failures in supporting processes such as charging, boiler dust collection, acid production, and slow slag cooling often necessitate long-term hot shutdowns.
[0003] Side-blown copper smelting furnaces are equipped with slag chamber partitions to separate slag and copper in the slag chamber area, thereby reducing the loss of valuable metals in the slag. During production, these partitions are often replaced by copper water jackets to ensure their service life. However, these water jackets are prone to slagging during furnace shutdowns, which can affect the normal flow of molten slag into the slag chamber, and the slag is difficult to melt. During production, unobstructed flow below the partition is often achieved by burning through the slag outlet. Sometimes, when the furnace shutdown is too long and excessive slag has formed, it is necessary to dismantle the copper water jacket near the partition and burn it open. This method involves a large amount of engineering work and consumes a lot of manpower and resources.
[0004] Existing treatment methods mainly focus on how to better achieve insulation of the partition wall, such as improving the natural gas gun, adjusting the addition of coke and coal, using the primary air vent to blow in oxygen for better insulation, and using the insulation electrode to conduct electricity for insulation. However, in cases where the partition wall is severely slag-forming, it is necessary to disassemble and install the water jacket. There are still problems such as complex treatment procedures and high consumption of manpower and material resources.
[0005] Furthermore, even if the slag in the slag chamber partition wall is burned through, there is still a possibility of slag forming again due to the low temperature inside the furnace. When the copper surface in the side-blown copper smelting furnace is high and there is slag that cannot pass through the slag chamber partition wall normally, if the concentrate is directly fed into the furnace for smelting, the slag chamber partition wall will soon be unable to pass through the slag. The long shutdown time often results in low copper temperature and difficulty in discharging copper matte. The copper matte siphon is difficult to handle, so it is necessary to discharge it from the spare copper matte discharge port, which greatly increases the economic loss. If it is discharged directly into the safety pit, it will further increase the consumption of manpower and material resources. Summary of the Invention
[0006] To address the aforementioned problems, this invention provides a method for starting a side-blown furnace with pyrite assistance. By partially or completely adding pyrite, the furnace temperature is rapidly increased to dissolve the slag buildup on the partition walls without raising the copper surface. Combined with a low-level standby slag outlet, normal flow of materials and heat within the furnace is achieved, thereby quickly restoring the various process parameters of the side-blown furnace to normal and achieving the goal of rapid and stable start-up of the side-blown furnace.
[0007] This invention is achieved through the following technical solution: A method for starting up a pyrite-assisted side-blown furnace involves feeding pyrite and copper concentrate at 10% to 70% of the maximum designed feed amount of the side-blown furnace by mass ratio. The mass ratio of pyrite to copper concentrate is (0-10):(0-10); The copper content of the pyrite is <1%; The furnace start-up includes cold start-up during initial production and hot start-up after a production interruption of more than 3 hours.
[0008] The sulfur and iron content of pyrite must meet the requirements of self-heating and releasing excess heat, so as to quickly increase the temperature inside the furnace. The specific content can be adjusted according to the size of the side-blown furnace. The input amounts of pyrite and copper concentrate, and their ratio, are adjusted based on the furnace temperature and the rise in copper level. During cold start-up, the copper level is only 0-200mm above the normal discharge height. However, during hot start-up, when parameters are abnormal or the furnace temperature needs to be rapidly increased, the input amount of pyrite is higher than that of copper concentrate, or even copper concentrate can be omitted, resulting in a pyrite to copper concentrate mass ratio of 10:0. In the later stages of start-up, normal production needs to be gradually restored while maintaining the furnace temperature naturally. Therefore, only copper concentrate needs to be added, eliminating the need for pyrite, resulting in a pyrite to copper concentrate mass ratio of 0:10. Simultaneously, the total amount of pyrite and copper concentrate input during start-up is 10%-70% of the maximum designed feed amount for the side-blown furnace. The copper content of the pyrite is required to be less than 1% to allow for adjustment of the side-blown furnace's process parameters even when the copper level barely rises. The chemical reactions of pyrite within the side-blown furnace are as follows: 2FeS2 = 2FeS + S2; 10Fe₂O₃ + FeS = 7Fe₃O₄ + SO₂; 16Fe₂O₃ + FeS₂ = 11Fe₃O₄ + 2SO₂; FeS+3Fe3O4+5SiO2=5(2FeO‧SiO2)+SO2; Cu₂O + FeS = Cu₂S + FeO; Pyrite completes the decomposition, oxidation, and slag formation processes through the above reactions, while releasing a large amount of heat to provide sufficient heat for the melting of the slag. At the same time, since the copper content of pyrite itself is less than 1%, when the oxygen potential in the furnace is kept basically unchanged, the addition of pyrite can achieve almost no rise in the copper level, cleverly avoiding the risk that a rapid rise in the copper level may cause the slag chamber partition wall to fail to pass through the slag.
[0009] Preferably, the steps for cold start-up are as follows: a1: First, use fuel to heat up the furnace according to the heating curve. Then, add wood and coke to the furnace in sequence. Next, add cold matte and slag to form a molten pool. Then, add concentrate, pyrite, quartz, coal and other materials to form a molten pool. When the temperature, copper matte grade and slag type in the side-blown furnace meet the process requirements, organize the normal discharge of slag and copper from the tap. a2: When the distance between the copper surface inside the furnace and the normal discharge height is 0-200mm during the furnace start-up process, but the parameters in the molten pool do not meet the normal production requirements, continue to start the furnace according to the input mass ratio of pyrite to concentrate of (5-10):(0-5) until the parameters of the side-blown furnace meet the process requirements. When the side-blown furnace completes the normal discharge process of slag and copper, the furnace is successfully started.
[0010] When the copper level inside the furnace is close to or about to reach the normal discharge height during the start-up process, but the parameters in the molten pool still do not meet the requirements, it is too risky to continue adding concentrate to adjust the furnace conditions. Pyrite should be added partially or completely to continue the start-up process until the parameters of the side-blown furnace meet the process requirements. During this process, the overflow slag outlet designed can be used normally according to the load. When the side-blown furnace completes the normal discharge process of slag and copper, the start-up is successful.
[0011] Preferably, the hot start-up process is as follows: b1: Stop feeding the side-blown furnace, discharge the slag to the commonly used slag outlet and the siphon outlet to stop the flow, and immediately use a natural gas gun to heat the slag chamber partition wall, and reduce the water flow of the partition wall water jacket so that the water jacket return water temperature is <50℃ and there is no gasification phenomenon in the return water. b2: Add 1 to 10 tons of fuel from each feeding port for insulation, and blow in the oxygen required for fuel combustion from the secondary air inlet. The oxygen flow rate is 1000 to 4000 Nm³ / h, and adjust the flow rate of the special natural gas gun for the partition wall to 50 to 600 Nm³ / h. b3: Feed the pyrite to concentrate at a mass ratio of (0-10):(0-10), and observe the surging of the slag chamber partition wall from the overflow slag outlet after feeding. b4: When the slag below the partition wall of the slag chamber is blocked by cooled slag and there is no slag flow in the slag chamber, it is necessary to use the low-level backup slag port of the slag chamber. The material circulation of the hot melt in the furnace is opened through the low-level backup slag port in the slag chamber area near the partition wall. When there is obvious slag flow in the slag chamber and the slag chamber temperature begins to rise to above 1200℃, concentrate is switched to be added or the proportion of concentrate is increased to complete the hot start-up of the furnace.
[0012] During the hot start-up process, fuel needs to be replenished according to the combustion of fuel in the furnace to ensure the heat preservation effect of the furnace. When resuming production, pyrite is first added at a low load to quickly raise the temperature inside the furnace. At the same time, slag is discharged from the relatively low standby slag outlet. The heat inside the furnace is fully transferred through the normal flow of hot melt in the furnace. Slag formation in the melting tuyere, crust formation in the furnace, especially slag formation below the slag chamber partition wall, can be observed through the slag outlet to determine whether the slag flow near the partition wall is smooth. The slag chamber temperature change can also be used for judgment. When there is obvious surging in the slag chamber and the slag chamber temperature begins to rise, concentrate or pyrite can be added and the concentrate ratio can be gradually increased to complete the hot start-up.
[0013] Preferably, the fuel is one or more of lump coal, coke, diesel oil, heavy oil, and natural gas; the slag chamber partition wall needs to be heated and insulated during the hot start-up process.
[0014] Preferably, the air hole is poked once every 3 to 6 hours with an air hole probe.
[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention can rapidly increase the temperature of the melt in a side-blown furnace without raising the copper surface. The high-temperature melt dissolves the slag on the partition wall, allowing the melt near the partition wall to quickly resume its flow, thereby achieving rapid and stable furnace start-up for stable production.
[0016] 2. This invention has a wide range of applications, applicable to both hot shutdown and cold start-up, effectively saving start-up time and manpower / material resources, thereby improving metal smelting efficiency. Furthermore, the method of this invention also offers valuable insights for start-up methods of furnaces with partition walls that are prone to molten flow obstruction. Attached Figure Description
[0017] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation
[0018] The present invention will be further described below with reference to the embodiments. Unless otherwise specified, the technical means used in the embodiments are all conventional technical means in the art.
[0019] To simplify the explanation, the main components of pyrite used in the examples are: H₂O 7.30%, Cu 0.50%, Fe 33.62%, S 39.82%, SiO₂ 14.62%, and others 4.14% (unless otherwise specified, all component contents are by mass percentage (wt%)). The main components of copper concentrate used in the examples are: H₂O 7.51%, Cu 21.50%, Fe 25.18%, S 28.01%, SiO₂ 12.11%, and others 5.69%.
[0020] Example 1 The side-blown furnace was shut down for 20 hours. A total of 15 tons of lump coal was intermittently added to the furnace for insulation. During the insulation period, the average natural gas flow rate was 800 Nm³. 3 At the time of resumption of production, pyrite was used as the sole feedstock, with a feed rate of 56.5 t / h, supplemented by 2 t of lump coal and 3.5 t of quartz. The total oxygen content of the primary air was 16200 Nm³. 3 / h, oxygen concentration 80%, theoretical iron-silicon ratio controlled at 1.52.
[0021] The original slag chamber partition wall height was 950mm, and the expected slag thickness below was greater than 50mm. Before feeding, the copper surface was 780mm and the slag surface was 2030mm. After feeding, no surging was observed from the overflow slag outlet through the partition wall of the slag chamber. The observation port revealed that the reaction temperature was high while the slag temperature discharged from the overflow slag outlet was low. The slag temperature was below 1280℃ for a long time. The overflow slag outlet was blocked, and two slag bags were discharged using a 1.2m spare slag outlet. Normal surging resumed near the partition wall, and the slag temperature gradually rose to over 1290℃. The overflow slag outlet was then used for normal slag discharge, and 100t of copper concentrate was fed in. The copper matte siphon was opened and the copper matte was discharged. The slag and copper matte discharge were normal. The final copper matte grade was 71.2wt%, the slag copper content was 1.3wt%, the slag temperature was 1310℃, and the iron-silicon ratio was 1.70. Production returned to normal.
[0022] Example 2 The side-blown furnace was shut down for 5 hours. A total of 5 tons of lump coal was intermittently added to the furnace for insulation. During the insulation period, the average natural gas flow rate was 1600 Nm³. 3 / h, the flow rate of the special natural gas gun for partition walls is 300 Nm 3 At the time of resumption of production, pyrite was partially added at a rate of 40 t / h, concentrate at a rate of 20 t / h, and auxiliary additions of 2 t of lump coal and 1.3 t of quartz were added. The total oxygen content of the primary air was 14950 Nm³. 3 / h, oxygen concentration 83%, theoretical iron-silicon ratio controlled at 1.72.
[0023] The original slag chamber partition wall height was 950mm, and the expected slag thickness below was greater than 50mm. Before feeding, the copper surface was 730mm and the slag surface was 2020mm. After feeding, the slag chamber partition wall flow was poor when observed from the overflow slag outlet. It was found that the time for each bag of slag to be fully discharged from the overflow slag outlet was 50% longer than normal. The observation port showed that the reaction temperature was high while the slag temperature discharged from the overflow slag outlet was low. The slag temperature was below 1270℃ for a long time and the temperature rose slowly. The slag surface was 2030mm while the copper surface was 750mm. The siphon outlet flow rate was small. Testing revealed that the slag contained more than 0.7 wt% sulfur and less than 12 wt% magnetic iron. There was no over-oxidation in the slag. The vent near the partition wall was opened and used for 30 minutes. A slag bag was discharged using the 1.2m spare slag outlet. The surge near the partition wall suddenly increased, and the slag temperature rapidly rose to over 1295℃. The overflow slag outlet was then used for normal slag discharge, and 120t of copper concentrate was added. The siphon flow increased and returned to normal, making cleaning and maintenance convenient. As a result, the discharge of slag and copper matte was normal. The final copper matte grade was 72.1 wt%, the slag copper content was 1.38 wt%, the slag temperature was 1317℃, and the iron-silicon ratio was 1.76. Production returned to normal.
[0024] Example 3 For cold start-up of the side-blown furnace, the temperature measured by the thermocouple at the top of the rising flue is used as a reference. First, the furnace temperature is gradually raised to 1200℃ according to the set heating curve. Then, 15t of firewood is manually added through the charging port, observation hole, and observation hole of the rising flue. The primary air volume is 5000Nm³ / h to 10000Nm³ / h depending on the combustion situation, and the oxygen concentration is 30%. 40t of coke is added in batches. After the coke is fully burned, 50t / h of slag, 25t / h of matte, and 6.0t / h of coke are added into the side-blown furnace to start building the molten pool. The oxygen concentration of the primary air is gradually increased from 30% to 60%. During the process, the total primary air volume and coal volume are adjusted in time according to the furnace temperature and the reaction situation in the furnace. The secondary air volume is adjusted by controlling the residual oxygen at 3%-5%. Subsequently, copper concentrate, coke powder, and quartz were added to build the molten pool. The charging rate was carefully controlled to ensure the molten pool temperature remained within the range of 1250–1300℃. The charging rate was gradually increased according to the furnace temperature, while simultaneously increasing the primary air oxygen concentration and the number of primary tuyeres opened, until normal air supply and pressure (110–120 kPa) were achieved. During the start-up process, multiple slag leaks and chemical pipeline leaks caused several material supply interruptions. At this point, the copper surface was 680 mm, the slag surface was 2000 mm, the slag chamber partition wall height was 950 mm, and the expected slag thickness at the bottom was greater than 100 mm. Pyrite was then added at a rate of 76.28 t / h, with 3 t of lump coal and 3.72 t of quartz added as auxiliary materials. The total primary air oxygen content was 22400 Nm³. 3 / h, oxygen concentration 80%, theoretical iron-silicon ratio controlled at 1.60.
[0025] After feeding, observation from the overflow slag outlet revealed poor slag flow in the slag chamber partition wall, making it impossible to discharge slag. Discharge was switched to a 1.2m standby slag outlet. Observation revealed a high reaction temperature but a low slag temperature discharged from the standby outlet, with the slag temperature remaining below 1270℃ for an extended period and rising slowly. The slag surface was 2040mm thick, while the copper surface was 690mm thick, resulting in low flow rate at the siphon outlet. Testing revealed a sulfur content greater than 1.0wt% and a magnetic iron content less than 12wt% in the slag. No over-oxidation was observed. The vent near the partition wall was opened, and the slag was used for 25 minutes, then stopped for 10 minutes, and then used again for 20 minutes. The three slag bags were discharged successively using the 1.2m spare slag outlet. The surge near the partition wall suddenly increased, and the slag temperature rose rapidly to over 1295℃. The overflow slag outlet returned to normal slag discharge, and 120t of copper concentrate was switched to the slag outlet. The flow rate of the siphon outlet increased and returned to normal, making cleaning and maintenance easier. As a result, the discharge of slag and copper matte was normal. The final copper matte grade was 72.8wt%, the copper content in the slag was 1.60wt%, the slag temperature was 1325℃, and the iron-silicon ratio was 1.74. Production returned to normal.
[0026] The above embodiments are merely exemplary embodiments of the present invention and are not intended to limit the present invention. The scope of protection of the present invention is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within its spirit and scope of protection, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of the present invention.
Claims
1. A method for starting up a pyrite-assisted side-blown furnace, characterized in that: By mass ratio, pyrite and copper concentrate are fed into the side-blown furnace at 10% to 70% of the maximum feed amount designed for the furnace. The mass ratio of pyrite to copper concentrate is (0-10):(0-10); The copper content of the pyrite is <1%; The furnace start-up includes cold start-up during initial production and hot start-up after a production interruption of more than 3 hours.
2. The method for starting up a pyrite auxiliary side-blown furnace according to claim 1, characterized in that, The steps for cold start-up of the furnace are as follows: a1: First, use fuel to heat up the furnace according to the heating curve. Then, add wood and coke to the furnace in sequence. Next, add cold matte and slag to form a molten pool. Then, add concentrate, pyrite, quartz, coal and other materials to form a molten pool. When the temperature, copper matte grade and slag type in the side-blown furnace meet the process requirements, organize the normal discharge of slag and copper from the tap. a2: When the distance between the copper surface inside the furnace and the normal discharge height is 0-200mm during the furnace start-up process, but the parameters in the molten pool do not meet the normal production requirements, continue to start the furnace according to the input mass ratio of pyrite to concentrate of (5-10):(0-5) until the parameters of the side-blown furnace meet the process requirements. When the side-blown furnace completes the normal discharge process of slag and copper, the furnace is successfully started.
3. The method for starting up a pyrite auxiliary side-blown furnace according to claim 1, characterized in that, The steps for hot start-up of the furnace are as follows: b1: Stop feeding the side-blown furnace, discharge the slag to the commonly used slag outlet and the siphon outlet to stop the flow, and immediately use a natural gas gun to heat the slag chamber partition wall, and reduce the water flow of the partition wall water jacket so that the water jacket return water temperature is <50℃ and there is no gasification phenomenon in the return water. b2: Add 1 to 10 tons of fuel from each feeding port for insulation, and blow in the oxygen required for fuel combustion from the secondary air inlet. The oxygen flow rate is 1000 to 4000 Nm³ / h, and adjust the flow rate of the special natural gas gun for the partition wall to 50 to 600 Nm³ / h. b3: Feed the pyrite to concentrate at a mass ratio of (0-10):(0-10), and observe the surging of the slag chamber partition wall from the overflow slag outlet after feeding. b4: When the slag below the partition wall of the slag chamber is blocked by cooled slag and there is no slag flow in the slag chamber, it is necessary to use the low-level backup slag port of the slag chamber. The material circulation of the hot melt in the furnace is opened through the low-level backup slag port in the slag chamber area near the partition wall. When there is obvious slag flow in the slag chamber and the slag chamber temperature begins to rise to above 1200℃, concentrate is switched to be added or the proportion of concentrate is increased to complete the hot start-up of the furnace.
4. The method for starting up a pyrite auxiliary side-blown furnace according to any one of claims 2 or 3, characterized in that: The fuel is one or more of lump coal, coke, diesel oil, heavy oil, and natural gas; During the hot start-up process, the partition walls of the slag chamber need to be heated and kept warm.
5. The method for starting up a pyrite auxiliary side-blown furnace according to claim 3, characterized in that: Every 3-6 hours, use a venting probe to poke the vent once.