A method for integrating bottom protection and rapid slagging during the baking process of a top-blown converter

Abstract

The present application relates to non-ferrous smelting technical field, specifically to a kind of top-blown converter baking process furnace bottom protection and fast slagging integrated method, comprising the following steps: cleaning top-blown converter in furnace sundries, according to furnace volume and design bath height, preloading copper matte in furnace, dry blowing slag is laid on the surface of copper matte as bottom layer protection slag;Start baking device, adopt zoning heating mode, when the temperature in furnace rises to 300-400 ℃, 2-4 h is kept warm;Continue to heat to 600-700 ℃, 3-5 h is kept warm;Continue to heat to 1100-1200 ℃, 4-6 h is kept warm, so that preloading copper matte is completely melted to form bath, while blowing slag and bath react to generate the slag that meets process requirements;During baking, the temperature of furnace bottom does not exceed 1250 ℃;In the later period of slagging, adjust air supply oxygen enrichment concentration to 25-35%, maintain the concentration until start-up is completed.The present application effectively avoids the over-temperature deformation of furnace bottom caused by direct flame burning, the deterioration rate of furnace wall refractory material is reduced by more than 60%, and the service life of furnace is prolonged by 30%-40%.

Description

Technical Field

[0001] This invention relates to the field of non-ferrous metal smelting technology, specifically to an integrated method for furnace bottom protection and rapid slag formation during the furnace drying process of a top-blown smelting furnace. Background Technology

[0002] Top-blown smelting furnaces are one of the core pieces of equipment in continuous smelting systems and are widely used in the smelting of non-ferrous metals such as copper. When using them for the first time or resuming production after a shutdown for maintenance, a furnace baking operation is required. The purpose of this operation is to gradually increase the furnace temperature, allowing the refractory materials to be fully dehydrated and preheated. This prevents thermal stress caused by sudden temperature changes when high-temperature melt is added later, which could lead to furnace deformation or cracking and spalling of the refractory materials.

[0003] Traditional furnace drying uses a single heat source for direct heating, with the flame acting directly on the furnace bottom. This results in excessively high local temperatures and uneven heating rates (differences can reach 20-30℃ / h). The refractory material at the furnace bottom is prone to deterioration and spalling due to excessive thermal stress, and may even cause overheating deformation, severely affecting the service life of the furnace. Slag formation must be carried out separately after the furnace drying is completed. The unreasonable feeding method and blasting system lead to slow slag formation and uneven composition, prolonging the start-up time of the entire system, which generally takes 7-10 days, resulting in huge energy consumption. Frequent wear and tear of the furnace bottom refractory material, energy waste due to long start-up cycles, and excessive consumption of oxygen lances due to improper oxygen concentration control significantly increase the total production cost.

[0004] To address these issues, some domestic companies have attempted to adopt zoned furnace drying technology or intelligent control systems. While these technologies have improved temperature uniformity to some extent, they have not achieved synergistic optimization of furnace bottom protection and rapid slag formation. Although induction heating furnace drying technology used abroad provides uniform heating, it has high equipment investment costs and is not suitable for the technical transformation of most existing top-blown smelting furnaces. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention provides an integrated method for bottom protection and rapid slag formation during the baking process of a top-blown smelting furnace.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] A method integrating furnace bottom protection and rapid slag formation during the furnace drying process of a top-blown refining furnace includes the following steps:

[0008] (1) Pre-treatment before furnace drying: Clean the debris inside the top-blown smelting furnace, and pre-load crude copper into the furnace according to the furnace volume and the designed molten pool height. The thickness of the crude copper layer is 10-30 cm. Dry smelting slag is laid on the surface of the crude copper as the bottom protective slag. The thickness of the bottom protective slag layer is 5-15 cm, and the moisture content is ≤0.5%.

[0009] (2) Layered temperature control oven: Start the oven device and adopt the zoned heating method. The initial heating rate of the bottom area is controlled at 5-10℃ / h, and the heating rate of the furnace wall and top area is controlled at 10-15℃ / h. When the temperature inside the furnace rises to 300-400℃, keep it at that temperature for 2-4 hours. When the temperature continues to rise to 600-700℃, keep it at that temperature for 3-5 hours.

[0010] (3) Adding blowing slag in batches: During the heat preservation stage when the furnace temperature reaches 300-400℃, add dry blowing slag for the first time, with the amount added being 30-50% of the mass of the bottom protective slag; during the heat preservation stage when the temperature rises to 600-700℃, add dry blowing slag for the second time, with the amount added being 50-80% of the mass of the bottom protective slag;

[0011] (4) The molten pool and slag formation are completed in tandem: continue to heat up to 1100-1200℃ and hold for 4-6 hours to completely melt the pre-loaded crude copper to form a molten pool. At the same time, the blowing slag reacts with the molten pool to generate slag that meets the process requirements. The furnace bottom temperature does not exceed 1250℃ during the furnace drying period.

[0012] (5) Optimization of oxygen enrichment control: In the later stage of slag formation, adjust the oxygen enrichment concentration of the air supply to 25-35% and maintain this concentration until the furnace is started.

[0013] Further, the crude copper in step (1) has a purity of ≥99.5% and a particle size of 5-20 cm; the dried smelting slag has a composition of 30-40% SiO2, 5-10% CaO, and 40-50% FeO by mass percentage, and a particle size of 1-5 mm.

[0014] Furthermore, in step (2), an infrared thermometer is used to monitor the temperature of each area inside the furnace in real time, with a temperature measurement accuracy of ≤±3℃.

[0015] Furthermore, the slag added in step (3) needs to be preheated at 100-200℃.

[0016] Furthermore, after the molten pool is formed in step (4), the height of the molten pool is controlled within ±5 cm of the design value.

[0017] Furthermore, in step (5), the oxygen concentration is controlled in real time by an online oxygen concentration monitoring instrument, with a control response time ≤ 10 s.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] 1. Significant Furnace Bottom Protection: Through the physical isolation of the bottom protective slag and the zoned temperature control design, the furnace bottom heating rate is uniform (deviation ≤5℃ / h), effectively avoiding furnace bottom overheating deformation caused by direct flame burning, reducing the deterioration rate of furnace wall refractory materials by more than 60%, and extending the service life of the furnace by 30%-40%;

[0020] 2. Significantly improved slag-making efficiency: The slag-making process is integrated with the furnace-baking process and carried out in a coordinated manner, eliminating the need for a separate slag-making step. The slag-making time is reduced by more than 50%, and the entire system's furnace start-up time is controlled within 20 hours, significantly improving production efficiency.

[0021] 3. Reduced overall costs: Reduced refractory material consumption and shorter start-up cycle lead to energy savings. Combined with optimized oxygen concentration, oxygen lance consumption is reduced by more than 40%, and the overall benefit of a single furnace start-up can reach more than 180,000 yuan.

[0022] 4. Easy to operate and highly applicable: No need to modify existing drying furnace equipment, it can be achieved simply through process optimization. It is compatible with top-blown refining furnaces of different volumes, and the raw materials are readily available and inexpensive, making it easy to promote and apply in industrial applications. Attached Figure Description

[0023] The embodiments of the present invention will be further described below with reference to the accompanying drawings, wherein:

[0024] Figure 1 A process flow diagram of the present invention is shown. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0026] Reference Appendix Figure 1 A method integrating furnace bottom protection and rapid slag formation during the baking process of a top-blown smelting furnace includes the following steps:

[0027] (1) Pre-treatment before furnace drying: Clean the debris inside the top-blown smelting furnace, and pre-load crude copper into the furnace according to the furnace volume and the designed molten pool height. The thickness of the crude copper layer is 10-30 cm. Dry smelting slag is laid on the surface of the crude copper as the bottom protective slag. The thickness of the bottom protective slag layer is 5-15 cm, and the moisture content is ≤0.5%.

[0028] (2) Layered temperature control oven: Start the oven device and adopt the zoned heating method. The initial heating rate of the bottom area is controlled at 5-10℃ / h, and the heating rate of the furnace wall and top area is controlled at 10-15℃ / h. When the temperature inside the furnace rises to 300-400℃, keep it at that temperature for 2-4 hours. When the temperature continues to rise to 600-700℃, keep it at that temperature for 3-5 hours.

[0029] (3) Adding blowing slag in batches: During the heat preservation stage when the furnace temperature reaches 300-400℃, add dry blowing slag for the first time, with the amount added being 30-50% of the mass of the bottom protective slag; during the heat preservation stage when the temperature rises to 600-700℃, add dry blowing slag for the second time, with the amount added being 50-80% of the mass of the bottom protective slag;

[0030] (4) The molten pool and slag formation are completed in tandem: continue to heat up to 1100-1200℃ and hold for 4-6 hours to completely melt the pre-loaded crude copper to form a molten pool. At the same time, the blowing slag reacts with the molten pool to generate slag that meets the process requirements. The furnace bottom temperature does not exceed 1250℃ during the furnace drying period.

[0031] (5) Optimization of oxygen enrichment control: In the later stage of slag formation, adjust the oxygen enrichment concentration of the air supply to 25-35% and maintain this concentration until the furnace is started.

[0032] In one embodiment of the present invention, the crude copper in step (1) has a purity of ≥99.5% and a particle size of 5-20 cm; the dried smelting slag comprises, by mass percentage, 30-40% SiO2, 5-10% CaO, and 40-50% FeO, with a particle size of 1-5 mm.

[0033] In one embodiment of the present invention, in step (2), an infrared thermometer is used to monitor the temperature of each area inside the furnace in real time, with a temperature measurement accuracy of ≤±3℃.

[0034] In one embodiment of the present invention, the slag added in step (3) needs to be preheated at 100-200°C.

[0035] In one embodiment of the present invention, after the molten pool is formed in step (4), the height of the molten pool is controlled within ±5cm of the design value.

[0036] In one embodiment of the present invention, the oxygen concentration in step (5) is controlled in real time by an online oxygen concentration monitor, and the control response time is ≤10 s.

[0037] Example 1

[0038] The effective volume of the top-blown smelting furnace in a copper smelter is 80 m³. 3 The designed molten pool height is 2.5 m. The furnace drying and slag-making operations are carried out using the method of this invention. The specific steps are as follows:

[0039] Pre-treatment before furnace drying: After cleaning the debris in the furnace, pre-load 99.5% pure crude copper with a particle size of 5 cm and a thickness of 10 cm, evenly covering the bottom of the furnace; then spread dry smelting slag (30% SiO2, 5% CaO, 40% FeO; particle size 1 mm; moisture content 0.5%) on the surface of the crude copper, with a thickness of 5 cm.

[0040] Layered temperature-controlled oven: When the oven is started, the initial heating rate of the oven bottom is 5℃ / h, and the heating rate of the oven walls and top is 10℃ / h; when the temperature reaches 300℃, it is held for 2 hours, and when the temperature continues to rise to 600℃, it is held for 3 hours; the temperature is monitored in real time throughout the process by an infrared thermometer (temperature measurement accuracy ≤±3℃), and the fuel supply is adjusted in combination with a natural gas turbine flow meter.

[0041] Slag is added in batches: the first addition of slag is made during the 300℃ holding stage, with the amount being 30% of the mass of the bottom protective slag. The added slag is preheated at 100℃. The second addition is made during the 600℃ holding stage, with the amount being 50% of the mass of the bottom protective slag. A uniform distribution method is used to ensure that the surface of the molten pool is covered.

[0042] The molten pool and slag formation are completed in tandem: the temperature is raised to 1100℃ and held for 4 hours. The crude copper is completely melted to form a molten pool. The height of the molten pool is controlled within ±5cm of the design value by the liquid level monitoring device. The furnace bottom temperature is continuously monitored during the furnace baking period and stabilized at 1200℃ without overheating deformation.

[0043] Oxygen enrichment regulation optimization: In the later stage of slag formation (slag formation rate ≥90%), adjust the oxygen enrichment concentration to 25% and regulate it in real time through an online oxygen concentration monitor (response time ≤10s) until the furnace start-up is completed.

[0044] The entire system took 19.8 hours to start up. The refractory materials of the furnace bottom and walls met the standards, and the deterioration rate was reduced by 60%. Oxygen lance consumption was reduced by 40% compared with the traditional method, and the comprehensive benefit of a single furnace was RMB 180,000.

[0045] Example 2

[0046] The effective volume of the top-blown smelting furnace in a non-ferrous metal smelter is 60 m³. 3 The designed molten pool height is 2.2 m, and the implementation steps are as follows:

[0047] Pre-treatment before furnace drying: Pre-load crude copper with a purity of 99.8% with a particle size of 20 cm and a thickness of 30 cm; then lay dry smelting slag (SiO2 40%, CaO 10%, FeO 50%; particle size 5 mm; moisture content 0.3%) with a thickness of 15 cm.

[0048] Layered temperature-controlled oven: The initial heating rate of the furnace bottom is 10℃ / h, and the heating rate of the furnace wall and furnace top is 15℃ / h; when the temperature reaches 400℃, it is held for 4 hours, and when the temperature continues to rise to 700℃, it is held for 5 hours; the temperature of each area is monitored in real time by an infrared thermometer to accurately control the fuel supply.

[0049] The blowing slag is added in batches: the blowing slag is added for the first time during the 400℃ holding stage, and the amount added is 50% of the mass of the bottom protective slag. The added slag is preheated at 200℃. The second addition is made during the 700℃ holding stage, and the amount added is 80% of the mass of the bottom protective slag, to ensure that the blowing slag continuously covers the surface of the molten pool.

[0050] The molten pool and slag formation are completed in synergy: the temperature is raised to 1200℃ and held for 6 hours, the crude copper is completely melted to form a stable molten pool, and the height of the molten pool is controlled within ±5cm of the design value; the furnace bottom temperature is stable at 1250℃, and there is no overheating deformation.

[0051] Oxygen enrichment regulation optimization: In the later stage of slag formation (slag formation rate ≥90%), adjust the oxygen enrichment concentration to 35% and regulate it in real time through an online oxygen concentration monitor (response time ≤10s) to maintain this concentration until the furnace start-up is completed.

[0052] The entire system took 17.0 hours to start up, refractory material consumption was reduced by 68%, and the service life of the furnace is expected to be extended by 40%. Oxygen lance consumption was reduced by 48% compared with traditional methods, and the comprehensive benefit of a single furnace was 195,000 yuan.

[0053] The beneficial effects of this invention are as follows:

[0054] 1. Significant Furnace Bottom Protection: Through the physical isolation of the bottom protective slag and the zoned temperature control design, the furnace bottom heating rate is uniform (deviation ≤5℃ / h), effectively avoiding furnace bottom overheating deformation caused by direct flame burning, reducing the deterioration rate of furnace wall refractory materials by more than 60%, and extending the service life of the furnace by 30%-40%;

[0055] 2. Significantly improved slag-making efficiency: The slag-making process is integrated with the furnace-baking process and carried out in a coordinated manner, eliminating the need for a separate slag-making step. The slag-making time is reduced by more than 50%, and the entire system's furnace start-up time is controlled within 20 hours, significantly improving production efficiency.

[0056] 3. Reduced overall costs: Reduced refractory material consumption and shorter start-up cycle lead to energy savings. Combined with optimized oxygen concentration, oxygen lance consumption is reduced by more than 40%, and the overall benefit of a single furnace start-up can reach more than 180,000 yuan.

[0057] 4. Easy to operate and highly applicable: No need to modify existing drying furnace equipment, it can be achieved simply through process optimization. It is compatible with top-blown refining furnaces of different volumes, and the raw materials are readily available and inexpensive, making it easy to promote and apply in industrial applications.

[0058] The foregoing descriptions have outlined some exemplary embodiments of the present invention. It is understood that these embodiments are merely illustrative and do not constitute a limitation on the scope of protection of the present invention. Features in these embodiments can be rearranged in suitable ways, and the resulting solutions remain within the scope of protection claimed by the present invention. All other embodiments obtained by those skilled in the art based on the foregoing embodiments without inventive effort, i.e., all modifications, equivalent substitutions, and improvements made within the spirit and principles of this application, fall within the scope of protection claimed by the present invention.

Claims

1. A method for integrating furnace bottom protection and rapid slag formation during the drying process of a top-blown smelting furnace, characterized in that, Includes the following steps: (1) Pre-treatment before furnace drying: Clean the debris inside the top-blown smelting furnace, and pre-load crude copper into the furnace according to the furnace volume and the designed molten pool height. The thickness of the crude copper layer is 10-30 cm. Dry smelting slag is laid on the surface of the crude copper as the bottom protective slag. The thickness of the bottom protective slag layer is 5-15 cm, and the moisture content is ≤0.5%. (2) Layered temperature control oven: Start the oven device and adopt the zoned heating method. The initial heating rate of the bottom area is controlled at 5-10℃ / h, and the heating rate of the furnace wall and top area is controlled at 10-15℃ / h. When the temperature inside the furnace rises to 300-400℃, keep it at that temperature for 2-4 hours. When the temperature continues to rise to 600-700℃, keep it at that temperature for 3-5 hours. (3) Adding blowing slag in batches: During the heat preservation stage when the furnace temperature reaches 300-400℃, add dry blowing slag for the first time, with the amount added being 30-50% of the mass of the bottom protective slag; during the heat preservation stage when the temperature rises to 600-700℃, add dry blowing slag for the second time, with the amount added being 50-80% of the mass of the bottom protective slag; (4) The molten pool and slag formation are completed in tandem: continue to heat up to 1100-1200℃ and hold for 4-6 hours to completely melt the pre-loaded crude copper to form a molten pool. At the same time, the blowing slag reacts with the molten pool to generate slag that meets the process requirements. The furnace bottom temperature does not exceed 1250℃ during the furnace drying period. (5) Optimization of oxygen enrichment control: In the later stage of slag formation, adjust the oxygen enrichment concentration of the air supply to 25-35% and maintain this concentration until the furnace is started.

2. The method according to claim 1, characterized in that, The crude copper in step (1) has a purity of ≥99.5% and a particle size of 5-20 cm; the dried smelting slag has a composition of SiO2 30-40%, CaO 5-10%, FeO 40-50% by mass percentage and a particle size of 1-5 mm.

3. The method according to claim 1, characterized in that, In step (2), an infrared thermometer is used to monitor the temperature of each area inside the furnace in real time, with a temperature measurement accuracy of ≤±3℃.

4. The method according to claim 1, characterized in that, The slag added in step (3) needs to be preheated at 100-200℃.

5. The method according to claim 1, characterized in that, After the molten pool is formed in step (4), the height of the molten pool is controlled within ±5 cm of the design value.

6. The method according to claim 1, characterized in that, In step (5), the oxygen concentration is controlled in real time by an online oxygen concentration monitor, with a control response time of ≤10 s.

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