Method for treating the clogging of the lance of a top-blown oxygen-enriched smelting furnace for nickel refining

Abstract

The application discloses a method for treating the clogging of a spray gun of a rich-oxygen top-blown smelting furnace for nickel refining, and belongs to the technical field of pyrometallurgy. The method effectively solves the technical problems of frequent clogging of the spray gun of a traditional top-blown smelting furnace, difficult cleaning, easy damage of the top equipment and influence on production continuity by spraying lime water inhibitor in the spray gun sleeve, adjusting the feed quantity and the slag type, controlling the low liquid level operation, strengthening the spray gun cooling, optimizing the fuel and rich-oxygen ratio, adjusting the negative pressure in the furnace and implementing the splash slag washing gun and other synergistic processes. The application can realize efficient removal of the clogging of the spray gun in the normal production process, significantly improves the system operation rate and the load rate, reduces the labor intensity, guarantees the production safety and realizes the high-load stable operation of the top-blown smelting furnace.

Description

Technical Field

[0001] This invention belongs to the field of pyrometallurgical technology, specifically relating to a method for treating tungsten nodules in oxygen-enriched top-blown nickel smelting furnaces. Background Technology

[0002] Oxygen-enriched top-blown smelting technology is one of the mainstream processes for processing nickel sulfide concentrate, with advantages such as high processing capacity and wide adaptability to raw materials. However, in actual production, the complex composition of the raw materials fed into the furnace, along with fluctuations in the content of volatile metals such as lead and zinc, as well as oxidized metals, can easily lead to an increase in the melting point and viscosity of the slag. Under the intense agitation of the molten pool by the top-blown lance, the high-temperature slag splashes and adheres to the outer wall of the lance sleeve, gradually accumulating to form nodules.

[0003] Nodule buildup on the spray gun can cause a series of serious problems: First, the buildup increases the weight of the spray gun, which may lead to "overweight and lifting restrictions" and prevent normal lifting; second, in emergency situations, forcibly lifting the spray gun can cause the nodule to easily scrape against the water-cooled components on the furnace top, resulting in water leakage and unplanned production stoppages; finally, frequent nodule buildup requires manual cleaning, which is labor-intensive and affects the system's operating rate, thus restricting the high-load stable production of the smelting furnace.

[0004] Traditional methods mainly include mechanical cleaning after shutdown or reducing furnace temperature to cause the slag to become brittle and fall off. Mechanical cleaning is inefficient, poses significant safety hazards, and requires production to be interrupted; reducing furnace temperature may affect normal smelting chemical reactions and slag formation, adversely affecting subsequent processes, and has a long processing cycle and is not thorough. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a method for treating nozzle buildup in the lances of an oxygen-enriched top-blown nickel smelting furnace. This method, through the coordinated adjustment of a series of process parameters, removes nozzle buildup online without interrupting the main production process, thus solving the safety hazards and low efficiency problems of traditional mechanical cleaning methods.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for treating tungsten nodules in an oxygen-enriched top-blown nickel smelting furnace includes the following steps: (1) Lime water inhibitor spraying: Lime water inhibitor is sprayed onto the sleeve of the top-blown smelting furnace lance. This step aims to form a protective / isolation layer on the lance surface in advance, change the interface properties of the lance wall, and inhibit the splashing and adhesion of new slag.

[0007] (2) Adjusting slag type and reducing slag viscosity: Temporarily adjust the feed rate from the normal load (e.g., 170 t / h) to 140-150 t / h of sulfide mixed semi-dry nickel concentrate. At the same time, adjust the ratio of flux (quartz, limestone) to control the slag composition, making its Fe / SiO2 ratio between 0.90 and 1.00, CaO / MgO ratio between 0.40 and 0.50, and controlling the slag temperature between 1300 and 1320℃. This combination of measures aims to obtain high-temperature, low-melting-point, and low-viscosity slag, creating fluid conditions for subsequent lance washing.

[0008] (3) Low liquid level operation: The liquid level of the molten pool is reduced from the normal 2.5~2.8m to 2.0~2.2m by actively discharging through the slag outlet. The low liquid level operation increases the upper oscillation and enhances the intensity of the lower molten slag droplet splash caused by the lance stirring.

[0009] (4) Enhance spray gun cooling: Increase the compressed air volume of the spray gun inner tube (e.g., increase by 1000~3000 Nm³ / h) to increase the gas flow rate, thereby enhancing the cooling intensity of the spray gun inner tube. This helps to reduce the temperature of the outer wall of the spray gun, creating a larger temperature gradient between the bonded nodules and the gun body, promoting the nodules to cool, shrink, and crack from the root.

[0010] (5) Optimize combustion and increase the temperature of the secondary combustion zone: Increase the oxygen supply to the lance sleeve (increase by 1000~20000 Nm³ / h) to achieve an oxygen enrichment concentration of 45~48%. At the same time, adjust the fuel structure, increase the amount of smokeless charcoal blocks (increase by 1.0~2.0 t / h), reduce the amount of pulverized coal used in the lance (reduce by 0.3~0.5 t / h), and appropriately reduce the negative pressure at the boiler inlet (to -20~-10 Kpa). These measures work together to significantly increase the temperature of the secondary combustion zone above the lance, increase the temperature of the outer interface of the nodule to keep its outer surface molten, increase the temperature gradient between the nodule and the lance body, and improve the scouring effect of the splashed molten slag.

[0011] (6) Slag-splashing and cleaning the lance: Increase the static pressure of the lance to 6.5~7.0 Kpa and control the depth of the lance insertion into the molten pool to 350~450mm. Under these parameters, the lance's agitation energy on the molten pool is enhanced, generating a large number of high-temperature, low-viscosity molten slag droplets that splash violently. At the same time, increase the lance's oscillation. The splashed molten slag droplets continuously scour the surface of the slag agglomerates on the lance, and the high temperature causes the molten agglomerates on the surface to fall off continuously, and the scouring action peels them off layer by layer. After this process lasts for 30~100 minutes, the agglomerates gradually become smaller, and their contact surface with the outer wall of the lance solidifies due to cooling. Under the combined action of their own gravity, the stress generated by the lance's oscillation, and the scouring action of the molten slag droplets, they finally completely fall off and enter the molten pool.

[0012] (7) Resume normal smelting: After confirming that the lance nodule treatment is completed, gradually increase the feed load back to the normal 170t / h. Adjust the composition of the materials fed into the furnace, reducing the proportion of metal oxides, secondary mixed nickel concentrate, and high-lead and high-zinc materials that are prone to nodule formation. Adjust the slag temperature back to 1280~1300℃, and restore the liquid level to 2.5~2.8m through normal discharge methods such as siphon wells, and switch to a stable smelting production state.

[0013] Preferably, in step (1), the lime water inhibitor is prepared by mixing quicklime and water at a mass ratio of 0.05:1.

[0014] Preferably, in step (2), the sulfide mixed semi-dry nickel concentrate is a mixture of nickel sulfide concentrate, nickel oxide concentrate, and nickel-containing dust, with a typical mass percentage composition of: Ni 5~8%, Cu 3~4%, Fe 29~31%, Co 0.10~0.20%, S 19~22%, SiO2 17.60~18.90%, CaO 1.70~1.85%, MgO 7.90~9.90%, Pb 0.020~0.025%, Zn 0.10~0.15%, As 0.021~0.029%, and H2O 10~12%.

[0015] Preferably, in step (4), the total air volume of the spray gun should be controlled at 50,000~53,000 Nm³ / h.

[0016] Preferably, in step (5), the particle size of the smokeless carbon block should be ≤50mm, and the quality requirements are C≥60%, S≤1%, volatile matter≥15%, ash content≤25%, and moisture content≤5%; the pulverized coal for the spray gun is required to contain C≥50%, S≤1%, volatile matter≥30%, ash content≤15%, and moisture content≤7%.

[0017] The beneficial effects of this invention are: 1. Online and efficient processing: By adjusting process parameters, this invention enables online removal of nodules with minimal production interruption, reducing processing time to less than 2 hours and greatly improving system operating rate and load rate.

[0018] 2. Safe and reliable: It avoids the risk of scraping the furnace top with the gun during traditional mechanical cleaning, completely eliminates the water leakage and production stoppage accidents caused by this, and ensures the safety of personnel and equipment.

[0019] 3. Low labor intensity: No manual high-intensity, high-temperature mechanical crushing operations are required, which significantly reduces the labor intensity and occupational health risks of the personnel.

[0020] 4. Significant synergistic effect: This invention is not a single method, but integrates a multi-step synergistic strategy of "prevention (spraying inhibitor) - creating conditions (adjusting slag type, increasing temperature, lowering liquid level) - active removal (enhancing cooling, splashing slag washing)". The mechanism is clear and the effect is stable.

[0021] 5. High operability: All adjustment parameters are based on the existing DCS control system, which is easy to operate and can be easily promoted and applied in industrial production. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to embodiments. These embodiments are used to explain the present invention, and not to limit the scope of protection of the present invention.

[0023] Example 1 During normal operation of a top-blown smelting furnace at a certain factory, the lance weight monitoring value continuously rose to the warning value, indicating severe nodule formation. Pre-treatment parameters: Before treatment, the top-blown smelting furnace was in normal smelting condition, with a concentrate mix of 170 t / h nickel-copper sulfide concentrate, 40 t / h nickel-copper oxide concentrate, 11 t / h anthracite, 3.8 t / h pulverized coal, 2.5 t / h anthracite briquettes, 22 t / h quartz, and 9 t / h limestone. The oxygen consumption coefficient of the coal was 1.2. The molten pool level was 2.6 m, the slag temperature was approximately 1280℃, the furnace mouth negative pressure was -15 kPa, and the lance airflow was 15000 m³ / h. 3 / h, oxygen supply to the sleeve 4700m 3 / h, the static pressure of the spray gun is 5.5kpa, the temperature at the top of the furnace is 910℃, and the weight of the spray gun is 7.6t.

[0024] Processing using the method of this invention: (1) During the lance change, spray lime water with a ratio of 0.05:1 on the sleeve of the top blow smelting furnace lance.

[0025] (2) Reduce the feed rate to 140 t / h of sulfide mixed nickel concentrate, and simultaneously adjust the flux to 18.2 t / h of quartz and 7.28 t / h of limestone, with the goal of making the slag Fe / SiO2≈0.95 and CaO / MgO≈0.45. Control the slag temperature to rise to about 1310℃.

[0026] (3) Open the slag outlet and lower the molten pool level to 2.1m.

[0027] (4) Increase the compressed air volume of the spray gun to 18,000 Nm³ / h, and the total air volume to about 50,000 Nm³ / h to enhance cooling.

[0028] (5) Increase the oxygen supply in the sleeve to 5500 Nm³ / h, increase the smokeless charcoal block to 3.5t / h, reduce the pulverized coal in the spray gun to 3.3t / h, and control the negative pressure at the boiler inlet to about -10kPa, so that the temperature in the secondary combustion zone will rise significantly.

[0029] (6) Increase the static pressure of the spray gun to 6.5 kPa, control the gun position to make the insertion depth about 400 mm, and increase the swing amplitude of the spray gun. The high temperature and low viscosity slag violently splashes and washes the lumps on the gun body. After about 60 minutes, the lumps are observed to have completely fallen off.

[0030] (7) After the nodule falls off, the feed rate is gradually restored to 170t / h, the proportion of nickel-copper oxide concentrate is reduced to 30t / h to reduce adverse effects, and the normal proportion of other fuels is restored. The liquid level is controlled at 2.6m by the siphon well, the slag temperature is stabilized at 1290℃, and the system resumes normal high-load production.

[0031] After treatment, the weight of the spray gun was reduced to 5.2t, eliminating the need to stop material handling to reduce the gun weight. This significantly improved the operating rate, and no issues of scraping or leaking water from the furnace top occurred.

[0032] Example 2 A method for treating tumblers on the lances of an oxygen-enriched top-blown nickel smelting furnace is disclosed. Before treatment, the top-blown smelting furnace is in normal smelting condition, with the concentrate mix consisting of 155 t / h nickel-copper sulfide concentrate, 50 t / h nickel-copper oxide concentrate, 12 t / h anthracite, 3.8 t / h pulverized coal, 2.7 t / h anthracite briquettes, 23.5 t / h quartz, and 9.6 t / h limestone. The oxygen consumption coefficient of the coal is 1.2, the molten pool level is 2.55 m, the slag temperature is 1267℃, the furnace mouth negative pressure is -20 kPa, the lance air volume is 15500 m³ / h, the sleeve oxygen volume is 5200 m³ / h, the lance static pressure is 6.0 kPa, the furnace top temperature is 925℃, and the lance weight is 8.8 t.

[0033] The specific steps are as follows: 1) During the lance change, spray a lime water inhibitor with a quicklime:water ratio of 0.05:1 onto the lance sleeve of the top-blown smelting furnace; 2) Adjust slag type: Adjust the feed rate to 145t / h of sulfide mixed semi-dry nickel concentrate (containing 10.5% H2O, composition meets requirements), add 17.6t / h of quartz and 7.1t / h of limestone according to Fe / SiO2=0.98 and CaO / MgO=0.48, and control the slag temperature at 1320℃; 3) Low liquid level operation: Lower the liquid level to 2.1m through the slag discharge outlet; 4) Enhanced cooling: Increase the compressed air volume of the spray gun to 19000 m³ / h, and control the total air volume of the spray gun to 52000 Nm³ / h; 5) Optimize combustion: Adjust the oxygen supply in the sleeve to 5800 m³ / h, control the oxygen enrichment concentration in the sleeve to 47%, increase the amount of smokeless coke to 5.5 t / h, reduce the amount of pulverized coal to 3.0 t / h, and control the negative pressure at the boiler inlet to -10 kPa; 6) Splashing and cleaning the spray gun: Adjust the static pressure of the spray gun to 7.0KPa, control the insertion depth of the spray gun to 420mm, increase the swing of the spray gun, and continue splashing and cleaning the spray gun for 80 minutes until the nodules on the spray gun are completely removed. 7) Resume normal smelting: Increase the feed load to 170t / h, reduce the amount of secondary mixed nickel concentrate and high zinc material fed into the furnace, reduce the ratio of nickel oxide copper concentrate to 35t / h, control the slag temperature to 1300℃ and the liquid level in the furnace to 2.7m, and resume normal production.

[0034] After treatment, the weight of the spray gun is reduced to 5.5t, eliminating the need to stop material processing to reduce gun weight. This significantly improves the operating rate, eliminates the need for manual cleaning of spray gun lumps by staff, and reduces labor intensity.

[0035] In summary, this invention, through technical solutions such as adjusting the feed rate of the top-blown smelting furnace, spraying lime water inhibitors on the outer wall of the spray lance, adjusting the negative pressure inside the furnace, optimizing the oxygen enrichment concentration of the spray lance, and controlling the spray lance position and fuel ratio, replaces the traditional mechanical cleaning method for treating spray lance nodules. This solves the problem of furnace top scraping and water leakage caused by spray lance nodule cleaning, significantly improving cleaning efficiency and system production rate. Simultaneously, it significantly reduces the labor intensity of personnel and ensures system production safety. This method is simple and convenient to operate. Through synergistic measures such as lime water inhibitor spraying, slag shape adjustment, low liquid level operation, enhanced spray lance cooling, combustion optimization, and slag splashing for lance cleaning, it effectively solves the problem of spray lance nodule formation in the top-blown smelting furnace production process. It further improves the nickel smelting production process, achieves stable high-load production of the top-blown smelting furnace, and improves the technical and economic indicators of nickel smelting production.

Claims

1. A method for treating tungsten nodules in an oxygen-enriched top-blown nickel smelting furnace, characterized in that, The steps include: (1) Spraying inhibitor: Spraying lime water inhibitor onto the sleeve of the top-blown smelting furnace spray gun; (2) Adjust smelting parameters: Adjust the feed rate of the top blown smelting furnace to 140~150t / h of sulfide mixed semi-dry nickel concentrate, control the slag temperature at 1300~1320℃, and add flux according to the ratio of Fe / SiO2=0.90~1.00 and CaO / MgO=0.40~0.50 in the smelting slag to reduce the slag viscosity; (3) Low liquid level operation: Lower the liquid level in the top blown smelting furnace to 2.0~2.2m and maintain low liquid level operation; (4) Enhance spray gun cooling: Increase the gas flow rate inside the spray gun to improve the cooling intensity of the spray gun; (5) Optimize combustion and temperature field: Adjust and increase the oxygen content of the sleeve, increase the amount of smokeless carbon blocks, reduce the amount of pulverized coal used in the spray gun, and reduce the negative pressure at the boiler inlet in order to increase the temperature of the secondary combustion zone in the furnace; (6) Slag splashing and cleaning the lance: Increase the static pressure of the lance, control the lance to be inserted into the molten pool to a depth of 350~450mm, and swing the lance to make the high temperature and low viscosity slag splash and wash the lance to remove the nodules. Continue for 30~100 minutes until the nodules fall off. (7) Restore normal smelting: After the nodules fall off, restore the normal smelting feed load and adjust the slag temperature and liquid level to the normal production range.

2. The method according to claim 1, characterized in that, In step (1), the lime water inhibitor is prepared by mixing quicklime and water at a mass ratio of 0.05:

1.

3. The method according to claim 1, characterized in that, In step (2), the flux is quartz and limestone.

4. The method according to claim 1, characterized in that, In step (2), the sulfide mixed semi-dry nickel concentrate comprises nickel sulfide concentrate, nickel oxide concentrate, and nickel-containing dust, with the following mass percentage composition: Ni 5~8wt%, Cu 3~4wt%, Fe 29~31wt%, Co 0.10~0.20wt%, S 19~22wt%, SiO2 17.60~18.90wt%, CaO 1.70~1.85wt%, MgO 7.90~9.90wt%, Pb 0.020~0.025wt%, Zn 0.10~0.15wt%, As 0.021~0.029wt%, and H2O 10~12%.

5. The method according to claim 1, characterized in that, In step (4), the gas flow rate inside the spray gun is increased by increasing the compressed air volume of the spray gun to 1000~3000 Nm³ / h, and the total air volume of the spray gun is controlled to be 50000~53000 Nm³ / h.

6. The method according to claim 1, characterized in that, In step (5), the anthracite lump coal has a particle size ≤50mm, contains C ≥60%, S ≤1%, volatile matter ≥15%, ash content ≤25%, and moisture content ≤5%; the pulverized coal contains C ≥50%, S ≤1%, volatile matter ≥30%, ash content ≤15%, and moisture content ≤7%.

7. The method according to claim 1, characterized in that, In step (5), the oxygen supply in the sleeve is increased by 1000~20000 Nm³ / h, and the oxygen concentration in the spray gun sleeve is controlled at 45~48%; the amount of smokeless carbon blocks is increased by 1.0~2.0 t / h, and the amount of pulverized coal in the spray gun is reduced by 0.3~0.5 t / h; the negative pressure at the boiler inlet is controlled at -20~-10 Kpa.

8. The method according to claim 1, characterized in that, In step (6), the static pressure of the spray gun is adjusted to 6.5~7.0 kPa.

9. The method according to claim 1, characterized in that, In step (7), restoring normal smelting includes increasing the feed load to 170 t / h, controlling the slag temperature to 1280~1300℃, controlling the molten pool liquid level to 2.5~2.8m, and reducing the proportion of metal oxides, secondary mixed nickel concentrate, high lead and high zinc materials fed into the furnace.