Smelting method of high-harmful-element sefstromite

Abstract

The invention belongs to the technical field of ferrous metallurgy, and particularly discloses a smelting method of high-harmful-element sefstromite, which provides a basis for stable smelting of a blast furnace by determining key indexes of raw materials and fuels, integrating that the grade of ore entering a furnace is greater than 55%, the thermal reactivity of coke is less than 45% and the strength after reaction is greater than 48%, and setting a reasonable smelting parameter range. And the characteristics of local high-harmful-element sefstromite can be handled. The problems that the content of harmful elements in local ore is high, ore blending before iron making and production stability are negatively affected, and the pig iron smelting cost is increased are solved. By utilizing the advantage of low cost and matching with a pre-ironmaking sintered ore batching mode and a pellet batching mode, airflow in a blast furnace is stable and reasonable in distribution, a hearth keeps uniform and active, long-period stable and smooth operation of the blast furnace is realized, the ore and coke blending cost is greatly reduced, and the cost of each ton of molten iron is reduced.

Description

Technical Field

[0001] This invention relates to the field of iron and steel metallurgy technology, specifically to a method for smelting vanadium-titanium iron ore, which is rich in harmful elements. Background Technology

[0003] This iron ore mine has high levels of harmful elements such as Zn, S, and P, and a large amount of vanadium-titanium iron ore resources. Although it has a low-cost advantage in terms of procurement price and transportation, the concentrated use of these special iron ores will have a negative impact on ironmaking blending and production stability. The coke produced from coking coal has excessively high reactivity (CRI 40-50%), low hot strength (CSR 40-50%), and high ash content, which brings great difficulty to the daily blast furnace smelting. Improper control can also cause abnormal furnace conditions, leading to increased pig iron smelting costs. Summary of the Invention

[0004] The purpose of this invention is to provide a smelting method for vanadium-titanium iron ore with high levels of harmful elements, in order to solve the problem that the high content of harmful elements in local mines negatively affects iron ore blending and production stability, leading to increased pig iron smelting costs.

[0005] To achieve the above objectives, the basic solution provided by this invention is as follows: a smelting method for vanadium-titanium iron ore with high levels of harmful elements, comprising sintering and pelletizing of incoming iron concentrate and ore powder, and simultaneously setting smelting conditions for blast furnace feed materials and fuels. The blast furnace feed materials include an overall ore grade greater than 55%, a zinc load greater than 1300 g / t, an alkali metal load greater than 3 kg / t, and a titanium load greater than 17 kg / t. The fuel conditions include a coke thermal reactivity of less than 45% and a post-reaction strength greater than 48%, in a volume of 1080 m³ / h. 3 The smelting takes place in a blast furnace; specific smelting conditions include: physical heat of molten iron: 1460-1500℃, titanium content of molten iron: 0.08-0.2%, silicon + titanium content of molten iron: 0.4-0.65%, slag basicity R2: 0.9-1.15 times, gas utilization rate: 40-43%, blast furnace permeability index: 16.5-18.5%, hot blast pressure: 345-370KPa, furnace top pressure: 170-195KPa, fuel ratio: 555-575kg / t, oxygen enrichment rate: 0-5.0%, taphole depth: 2700-2900mm, water temperature difference in the blast furnace waist: 0.8-3.5℃, water temperature difference in the lower part of the blast furnace body: 2-7℃, water temperature difference in the middle part of the blast furnace body: 3-10℃, and other smelting conditions are set conventionally.

[0006] The beneficial effects of this invention are as follows: By clearly defining key indicators of raw materials and fuels, comprehensively ensuring that the grade of ore fed into the furnace is greater than 55%, the thermal reactivity of coke is less than 45%, and the post-reaction strength is greater than 48%, and simultaneously setting a reasonable range of smelting parameters, a foundation is provided for stable blast furnace smelting, which can address the characteristics of local vanadium-titanium iron ore with high levels of harmful elements. While utilizing its low-cost advantage, combined with the pre-iron sintering ore and pelletizing ore batching modes, the airflow inside the blast furnace is stabilized and rationally distributed, and the hearth remains uniform and active, achieving long-term stable operation of the blast furnace, significantly reducing the cost of ore and coke blending, and thus lowering the cost per ton of molten iron.

[0007] Option 2, an optimized version of the basic option, is as follows: When the titanium content in the molten iron is 0.08-0.15%, the silicon + titanium content in the molten iron is 0.4-0.6%, the physical heat of the molten iron is 1460-1490℃, the blast furnace permeability index is 16.5-18.5%, the overall grade of the ore fed into the furnace is ≥55%, the zinc load in the blast furnace is ≥1300g / t, the alkali metal load in the blast furnace is ≥3kg / t, the titanium load in the blast furnace is ≥17kg / t, the thermal reactivity of the coke is ≤45%, the strength of the coke after reaction is ≥48%, and the zinc deposition in the blast furnace is ≤15t, while simultaneously ensuring good slag fluidity, uniform charging within the furnace, and a stable charging rate of 7-8 batches / h, and normal furnace operation, the following operations should be performed: control the slag basicity R2 to 1.05-1.15 times, and the furnace top pressure to 195... The blast furnace operates at a pressure of 370 kPa, with an oxygen enrichment rate of 5% and a taphole depth of 2900 mm. The water temperature difference at the blast furnace waist is 0.8-1.2℃, at the lower part of the blast furnace body is 2.0-3.0℃, and in the middle part of the blast furnace body is 3-5℃. The blast furnace gas flow distribution is adjusted to maintain unobstructed central airflow while ensuring stable edge airflow. The central temperature is controlled at 350-450℃, and the edge temperature at 100-150℃. Gas utilization is pushed towards the upper limit, and fuel ratio is controlled at the lower limit to ensure qualified molten iron quality. For normal furnace conditions, precise control of various parameters is employed to maintain unobstructed central airflow while ensuring stable edge airflow, ensuring gas utilization is pushed towards the upper limit and fuel ratio is controlled at the lower limit. This approach ensures qualified molten iron quality while improving energy efficiency and reducing energy costs.

[0008] Option 3, an optimized version of the basic option, is proposed when the molten iron contains 0.1-0.2% titanium, 0.45-0.65% silicon + titanium, has a physical heat of 1460-1500℃, a blast furnace permeability index of 16.5-18.5%, a comprehensive ore grade ≥55%, a blast furnace zinc load ≥1300g / t, a blast furnace alkali metal load ≥3kg / t, a blast furnace titanium load ≥17kg / t, coke thermal reactivity ≤45%, coke post-reaction strength ≥48%, and zinc deposition in the blast furnace ≥15t. Simultaneously, if the slag fluidity is generally normal, the charge within the furnace is uneven, the charge rate fluctuates at 6-8 batches / h, and the furnace conditions show slight fluctuations, then the following operations should be performed: control the slag basicity R2 to 1.0-1.1 times, add 200kg of magnesite to each batch, and ensure the magnesium-aluminum ratio in the slag is ≥0.6 times. The furnace top pressure is 185 kPa, the hot blast pressure is 360 kPa, the oxygen enrichment rate is 3.5%, the taphole depth is 2800 mm, the water temperature difference in the blast furnace waist is 1.0-2.0℃, the water temperature difference in the lower part of the blast furnace body is 3-4℃, and the water temperature difference in the middle part of the blast furnace body is 4-6℃. The blast furnace gas flow distribution is adjusted to guide the edge airflow while ensuring the stability of the central airflow. The central temperature is controlled at 300-400℃, the edge temperature at 150-200℃, the gas utilization rate is brought closer to the middle limit, and the fuel ratio is controlled towards the middle limit to ensure the quality of molten iron is qualified. When the furnace condition fluctuates slightly, 200 kg of magnesite is added to the batch and the slag magnesium-aluminum ratio is controlled at ≥0.6 times to improve the slag performance. Combined with the adjustment of the furnace top pressure and hot blast pressure parameters, the furnace condition fluctuations can be quickly alleviated and the blast furnace can be restored to normal production status by guiding the edge airflow while ensuring the stability of the central airflow.

[0009] Option 4, an optimal choice from the basic option, is as follows: When the molten iron contains 0.15-0.2% titanium, 0.5-0.65% silicon + titanium, has a physical heat of 1470-1500℃, a blast furnace permeability index of 16.5-18.5%, a comprehensive ore grade ≥55%, a blast furnace zinc load ≥1300g / t, a blast furnace alkali metal load ≥3kg / t, a blast furnace titanium load ≥17kg / t, coke thermal reactivity ≤45%, coke post-reaction strength ≥48%, and zinc deposition in the blast furnace ≥30t, while simultaneously meeting the following conditions: slag fluidity is generally good, but the charge within the furnace is uneven and slippage occurs, with the charge rate fluctuating at 5-8 batches / h, resulting in significant fluctuations in furnace conditions. In this case, the following operations should be performed: control the slag basicity R2 to 0.9-1.0 times, add 200kg of fluorite and 150kg of manganese ore to the batch charge, and control the furnace top pressure... The blast furnace operating conditions are as follows: 180 kPa hot blast pressure, 355 kPa hot blast pressure, 2.5% oxygen enrichment, 2700 mm taphole depth, 1.5-2.5℃ water temperature difference in the blast furnace waist, 3.5-5.5℃ water temperature difference in the lower part of the blast furnace body, and 4-8℃ water temperature difference in the middle part of the blast furnace body. The blast furnace gas flow distribution is adjusted by narrowing the charging platform and strongly developing the central and edge airflows. The central temperature is controlled at 400-500℃, and the edge temperature at 150-250℃. The gas utilization rate is brought closer to the lower limit, and the fuel ratio is controlled to the upper limit to ensure qualified molten iron quality. In response to significant fluctuations in furnace conditions and slippage, 200 kg of fluorite and 150 kg of manganese ore are added to adjust the slag basicity to 0.9-1.0 times, improving slag fluidity. Simultaneously, narrowing the charging platform and strongly developing the central and edge airflows solves the problem of uneven charging and ensures smooth blast furnace charging.

[0010] Option 5, an optimal choice from the basic option, is based on the following conditions: molten iron contains 0.15-0.2% titanium, 0.5-0.65% silicon + titanium, has a physical heat of 1475-1500℃, a blast furnace permeability index of 16.5-18.5%, a comprehensive ore grade ≥55%, a blast furnace zinc load ≥1300g / t, a blast furnace alkali metal load ≥3kg / t, a blast furnace titanium load ≥17kg / t, and a coke thermal reaction... If the slag basicity is ≤45%, the coke strength after reaction is ≥48%, the zinc deposition in the blast furnace is ≥50t, and the slag fluidity is generally acceptable, but uneven feeding in the furnace results in slippage, collapse, and hanging of material, with fluctuations in the material rate at 4-8 batches / h, and significant fluctuations in furnace conditions, then the following operations should be performed: control the slag basicity R2 to 0.9-1.0 times, add 300kg of fluorite and 250kg of manganese ore to the batch feed, and reduce the ore and coke load by 0.1-0.2 times. The feed line is adjusted to 2-3m, the furnace top pressure is 170KPa, the hot blast pressure is 345KPa, the oxygen enrichment rate is 0%, the taphole depth is 2700mm, the water temperature difference in the blast furnace waist is 2.5-3.5℃, the water temperature difference in the lower part of the blast furnace body is 5-7℃, and the water temperature difference in the middle part of the blast furnace body is 6-10℃. The blast furnace gas flow distribution is adjusted to strongly guide the edge airflow to ensure smooth feeding while reducing the proportion of coke in the center. The center temperature is controlled at 300-400℃, the edge temperature is 180-250℃, the lower limit of gas utilization rate and the upper limit of fuel ratio are controlled to ensure qualified iron quality. For obvious fluctuations in furnace conditions and the occurrence of slippage, collapse, and hanging of materials, measures are taken to increase the amount of fluorite (300kg) and manganese ore (250kg), and to reduce the load of coke and feed line. Strongly guiding the edge airflow to ensure smooth feeding can effectively solve serious furnace condition problems and avoid blast furnace shutdown or a significant drop in production efficiency.

[0011] Option 6 is an optimal choice of the basic option. The charging matrix is ​​selected such that the initial α angle of the charging is 1-2° smaller than the collision point angle, and the material line depth is 300-500mm lower than the normal material line. By selecting the initial α angle of the charging is 1-2° smaller than the collision point angle and the material line depth is 300-500mm lower than the normal material line, the blast furnace charging system is optimized, the resistance to gas rise is reduced, the permeability of the upper part is ensured, the uniformity of gas distribution is improved, the gas utilization rate is increased, thereby reducing fuel consumption and improving the blast furnace smelting efficiency.

[0012] Option 7 is an optimal choice of the basic option. It involves using fewer than three types of coke for blast furnace feeding, ensuring that the proportion of high-temperature coke is greater than 60%, the basicity qualification rate of the ore fed into the furnace is greater than 98%, and the powder rate is less than 5%. It controls the use of fewer than three types of coke for blast furnace feeding and ensures that the proportion of high-temperature coke is greater than 60%, thereby ensuring stable coke quality and reducing the impact of coke quality fluctuations on blast furnace smelting. The basicity qualification rate of the ore fed into the furnace is greater than 98%, and the powder rate is less than 5%, thereby ensuring stable performance of the ore fed into the furnace.

[0013] Option 8, an optimal choice from the basic option, stabilizes the blast furnace thermal regime, ensuring a slag-iron PT value ≥1480℃, and using a top temperature ≥180℃ as the benchmark for zinc removal, while maintaining a zinc content of no less than 17.5% in the gas ash. A stable blast furnace thermal regime, ensuring a slag-iron PT value ≥1480℃, provides sufficient heat for various chemical reactions within the blast furnace, ensuring the smooth progress of the smelting process. Using a top temperature ≥180℃ as the benchmark for zinc removal and ensuring a zinc content of no less than 17.5% in the gas ash effectively reduces the cyclic enrichment of zinc within the blast furnace, reduces zinc erosion of the blast furnace lining, and extends the blast furnace's service life. Detailed Implementation

[0014] The present invention will be further described in detail below through specific embodiments: A smelting method for vanadium-titanium iron ore with high levels of harmful elements involves sintering and pelletizing the incoming iron concentrate and ore powder, while simultaneously setting blast furnace feed and fuel smelting conditions. The blast furnace feed includes an overall ore grade greater than 55%, a zinc load greater than 1300 g / t, an alkali metal load greater than 3 kg / t, and a titanium load greater than 17 kg / t. Fuel conditions include a coke thermal reactivity of less than 45% and a post-reaction strength greater than 48%, all within a volume of 1080 m³. 3The smelting takes place in a blast furnace; specific smelting conditions include: physical heat of molten iron: 1460-1500℃, titanium content in molten iron: 0.08-0.2%, silicon + titanium content in molten iron: 0.4-0.65%, slag basicity R2: 0.9-1.15 times, gas utilization rate: 40-43%, blast furnace permeability index: 16.5-18.5%, hot blast pressure: 345-370KPa, and furnace top pressure: 170-195KPa. Fuel ratio: 555-575 kg / t; Oxygen enrichment rate: 0-5.0%; Taphole depth: 2700-2900 mm; Water temperature difference in the blast furnace waist: 0.8-3.5℃; Water temperature difference in the lower part of the blast furnace body: 2-7℃; Water temperature difference in the middle part of the blast furnace body: 3-10℃. Stabilize the quality and structure of raw materials and fuels at the front end, keep the coke feed structure as unchanged as possible, use fewer than 3 types of coke, ensure the proportion of high-heat coke is >60%, and feed ore... The alkalinity qualification rate is ≥98%, and the powder rate is <5%. A stable blast furnace thermal regime is maintained to ensure sufficient heat in the hearth, with a slag-iron PT value ≥1480℃. Zinc removal is based on a top temperature ≥180℃, ensuring that the zinc content in the gas ash is not less than 17.5%, effectively reducing the cyclic enrichment of harmful elements. The slag-forming regime is improved to achieve the lower limit level while ensuring desulfurization, increasing the permeability of the hearth, and reducing the viscosity of the slag liquid to between 1.0-1.5 Pa·s. The charging regime is optimized to stabilize gas utilization, selecting a suitable charging matrix and material line depth. Under normal circumstances, the initial α angle of the charging should be 1-2° smaller than the collision point angle, and the material line depth should be 300-500mm lower than the normal material line depth to reduce the resistance to gas rise and ensure upper permeability. The blast system is adjusted to ensure a uniform and reasonable initial gas distribution, with the swirling zone depth reaching 1 / 2 of the hearth radius, and the furnace belly gas index maintained at 65-75m. 3 / (min.m 2 Between 100-120 kg / t; appropriately reducing the coke ratio and increasing the coal ratio to achieve a coal ratio of 100-120 kg / t can effectively reduce the theoretical combustion temperature at the tuyeres and increase the oxygen enrichment rate. Under these vanadium-titanium ore smelting conditions with high levels of harmful elements, the theoretical combustion temperature at the tuyeres should not exceed 2350℃; strengthen iron tapping management, adopt a single-drill opening method, use Ф45mm and Ф38mm drill bits to drill the iron tapping opening, and achieve an iron tapping flow rate ≥3t / min to achieve the principle of "fast in and fast out" and ensure that theoretical slag and iron can be discharged in a timely manner; the remaining smelting conditions are set as usual.

[0015] When the molten iron contains 0.08-0.15% titanium, 0.4-0.6% silicon + titanium, and has a physical heat of 1460-1490℃, a blast furnace permeability index of 16.5-18.5%, a comprehensive ore grade ≥55%, a blast furnace zinc load ≥1300g / t, a blast furnace alkali metal load ≥3kg / t, a blast furnace titanium load ≥17kg / t, coke thermal reactivity ≤45%, coke post-reaction strength ≥48%, and zinc deposition ≤15t, while also meeting the requirements of good slag fluidity (slag FeO <1%, no crusting in the main ditch and slag ditch, no need for manual or mechanical diversion, slag automatically flows into the slag flushing trough along the designated ditch without overflowing outside the ditch), the slag sample after cooling is grayish-brown or bright yellow in cross-section, has a uniform texture and a glassy luster, and no large amount of white smoke is emitted from the taphole. If the molten iron shows fine sparks, a bright white surface without oil film, good slag-iron separation, and excellent desulfurization, indicating a suitable furnace temperature, abundant heat, good slag-iron fluidity, and an active hearth, and the furnace is operating normally with uniform feeding and a stable feeding rate of 7-8 batches / h, then the following operations should be performed: Control the slag basicity R2 to 1.05-1.15 times, the furnace top pressure to 195 kPa, the hot blast pressure to 370 kPa, the oxygen enrichment rate to 5%, the taphole depth to 2900 mm, the water temperature difference in the blast furnace waist to 0.8-1.2℃, the water temperature difference in the lower part of the blast furnace body to 2.0-3.0℃, and the water temperature difference in the middle part of the blast furnace body to 3-5℃. Adjust the blast furnace gas flow distribution to maintain smooth central airflow while ensuring stable edge airflow, controlling the central temperature to 350-450℃ and the edge temperature to 100-150℃. Optimize the gas utilization rate towards the upper limit and control the fuel ratio towards the lower limit to ensure qualified molten iron quality.

[0016] When the titanium content in molten iron is 0.1-0.2%, the silicon + titanium content in molten iron is 0.45-0.65%, the physical heat of molten iron is 1460-1500℃, the blast furnace permeability index is 16.5-18.5%, the overall grade of ore fed into the furnace is ≥55%, the zinc load in the blast furnace is ≥1300g / t, the alkali metal load in the blast furnace is ≥3kg / t, the titanium load in the blast furnace is ≥17kg / t, the thermal reactivity of coke is ≤45%, the strength of coke after reaction is ≥48%, the amount of zinc element deposited in the blast furnace is ≥15t, and at the same time, the slag fluidity is generally good, the charging in the furnace is uneven, the charging rate fluctuates at 6-8 batches / h, and the furnace condition shows slight fluctuations, then the following operations should be performed: control The slag basicity R2 is 1.0-1.1 times, 200 kg of magnesite is added to the batch, the magnesium-aluminum ratio in the slag is ≥0.6 times, the furnace top pressure is 185 kPa, the hot blast pressure is 360 kPa, the oxygen enrichment rate is 3.5%, the taphole depth is 2800 mm, the water temperature difference in the blast furnace waist is 1.0-2.0℃, the water temperature difference in the lower part of the blast furnace body is 3-4℃, and the water temperature difference in the middle part of the blast furnace body is 4-6℃. The blast furnace gas flow distribution is adjusted to guide the edge gas flow while ensuring the stability of the center gas flow. The center temperature is controlled at 300-400℃, the edge temperature is 150-200℃, the gas utilization rate is close to the middle limit, the fuel ratio is controlled at the middle limit, and the quality of molten iron is guaranteed to be qualified.

[0017] When the molten iron contains 0.15-0.2% titanium, 0.5-0.65% silicon + titanium, has a physical heat of 1470-1500℃, a blast furnace permeability index of 16.5-18.5%, a comprehensive ore grade ≥55%, a blast furnace zinc load ≥1300g / t, a blast furnace alkali metal load ≥3kg / t, a blast furnace titanium load ≥17kg / t, coke thermal reactivity ≤45%, and coke post-reaction strength ≥48%, the zinc content in the blast furnace... Element deposition amount ≥30t, while meeting the following requirements: slag fluidity is generally poor (slow flow in the trench, viscous, easily condenses at the trench edge, requiring manual and mechanical guidance, prone to crusting; slag cross-section is black after cooling; ferrous iron content significantly increases >1.5%; crusting occurs in the main trench; large amount of smoke and dust in the taphole area; obvious iron sparks; molten iron is dark red; a layer of oil film appears on the surface of the molten iron; sulfur content in the molten iron is significantly increased; tuyeres operate unevenly; large amounts of raw material flow into some tuyeres). If the furnace temperature drops or the slag skin peels off, indicating insufficient furnace temperature, poor slag-iron fluidity, inactive hearth, and unstable gas flow, and if the charge feed is uneven and slippage occurs, with the charge rate fluctuating at 5-8 batches / hour, and the furnace conditions show significant fluctuations, then the following operations should be performed: Control the slag basicity R2 to 0.9-1.0 times, add 200kg of fluorite and 150kg of manganese ore to the batch charge, control the furnace top pressure to 180kPa, the hot blast pressure to 355kPa, and the oxygen enrichment rate to 2.5%. The taphole depth is 2700mm. The water temperature difference in the blast furnace waist is 1.5-2.5℃, the water temperature difference in the lower part of the blast furnace body is 3.5-5.5℃, and the water temperature difference in the middle part of the blast furnace body is 4-8℃. The blast furnace gas flow distribution is adjusted to narrow the charging platform, strongly develop the two gas flows in the center and at the edge, control the center temperature at 400-500℃, the edge temperature at 150-250℃, bring the gas utilization rate closer to the lower limit, and control the fuel ratio to the upper limit to ensure the quality of molten iron is qualified.

[0018] When the titanium content in molten iron is 0.15-0.2%, the silicon + titanium content in molten iron is 0.5-0.65%, the physical heat of molten iron is 1475-1500℃, the blast furnace permeability index is 16.5-18.5%, the overall grade of ore fed into the furnace is ≥55%, the zinc load in the blast furnace is ≥1300g / t, the alkali metal load in the blast furnace is ≥3kg / t, the titanium load in the blast furnace is ≥17kg / t, the thermal reactivity of coke is ≤45%, the strength of coke after reaction is ≥48%, the zinc deposition in the blast furnace is ≥50t, and at the same time, the slag fluidity is generally good, the charging in the furnace is uneven and produces slippage, collapse and hanging phenomena, and the material rate fluctuates at 4-8 batches / h, and the furnace conditions fluctuate significantly, then the following operations should be performed: control the slag basicity. R2 is 0.9-1.0 times, with 300kg of fluorite and 250kg of manganese ore added to the batch. The ore and coke load is reduced by 0.1-0.2 times, the material line is lowered to 2-3m, the furnace top pressure is 170KPa, the hot blast pressure is 345KPa, the oxygen enrichment rate is 0%, the taphole depth is 2700mm, the water temperature difference in the blast furnace waist is 2.5-3.5℃, the water temperature difference in the lower part of the blast furnace body is 5-7℃, and the water temperature difference in the middle part of the blast furnace body is 6-10℃. The blast furnace gas flow distribution is adjusted to strongly guide the edge airflow to ensure smooth material feeding while reducing the proportion of ore and coke in the center. The center temperature is controlled at 300-400℃, the edge temperature is 180-250℃, the lower limit of gas utilization rate and the upper limit of fuel ratio are controlled to ensure the quality of molten iron is qualified.

[0019] This invention achieves stable coke and ore blending structures, enabling the smelting of vanadium-titanium ores with high levels of harmful elements. Under conditions of zinc load > 1.3 kg / t, alkali load > 3.5 kg / t, and titanium load > 17 kg / t, at a furnace depth of 1080 m³ / t... 3 The blast furnace utilization rate exceeded 4.0, with a monthly output of 127,200 tons. Under conditions of extremely high levels of harmful elements, the vanadium-titanium ore resources were fully utilized, effectively reducing the cost of molten iron to an average of about 1,900 yuan / ton, thus improving the company's market competitiveness.

[0020] Table 1. Production indicators for blast furnace smelting of vanadium-titanium ore date Zinc loading (kg / t) Alkali load (kg / t) S load (kg / t) <![CDATA[TiO2 loading (kg / t)]]> Fuel ratio (kg / t) Production (t) 2.10 1.32 2.79 2.61 13.50 555 3966 2.11 1.42 3.09 2.74 14.20 554 4052 2.12 1.39 2.97 2.97 14.60 554 4088 2.13 1.34 2.96 2.91 14.11 552 4148 2.14 1.33 2.93 2.77 15.37 553 4060 2.15 1.34 2.87 2.89 15.30 557 3821 2.16 1.43 2.96 2.77 15.37 551 3917 2.17 1.44 2.86 2.82 16.46 551 3465 2.18 1.51 2.69 2.86 16.83 554 3940 2.19 1.41 2.89 2.73 16.47 550 4031 2.20 1.37 2.94 2.88 16.21 539 4158 2.20 1.37 2.94 2.88 16.21 539 4158 2.21 1.39 3.22 2.92 16.67 542 4070 2.22 1.33 3.04 2.71 17.70 542 4053 2.23 1.31 3.01 2.65 17.80 541 4185 2.24 1.31 3.14 2.63 17.19 546 3852 2.25 1.31 3.26 2.81 18.40 537 4192 average 1.37 2.98 2.79 16.01 549 4000 The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for smelting vanadium-titanium iron ore with high levels of harmful elements, characterized in that, Based on the incoming iron concentrate and ore fines, sintering and pelletizing are carried out. Simultaneously, smelting conditions for blast furnace feed materials and fuels are set. Blast furnace feed materials include a comprehensive ore grade greater than 55%, a zinc load greater than 1300 g / t, an alkali metal load greater than 3 kg / t, and a titanium load greater than 17 kg / t. Fuel conditions include coke thermal reactivity less than 45% and coke post-reaction strength greater than 48%, in a volume of 1080 m³. 3 The smelting takes place in a blast furnace; specific smelting conditions include: physical heat of molten iron: 1460-1500℃, titanium content of molten iron: 0.08-0.2%, silicon + titanium content of molten iron: 0.4-0.65%, slag basicity R2: 0.9-1.15 times, gas utilization rate: 40-43%, blast furnace permeability index: 16.5-18.5%, hot blast pressure: 345-370KPa, furnace top pressure: 170-195KPa, fuel ratio: 555-575kg / t, oxygen enrichment rate: 0-5.0%, taphole depth: 2700-2900mm, water temperature difference in the blast furnace waist: 0.8-3.5℃, water temperature difference in the lower part of the blast furnace body: 2-7℃, water temperature difference in the middle part of the blast furnace body: 3-10℃, and other smelting conditions are set conventionally.

2. The smelting method for vanadium-titanium iron ore with high levels of harmful elements according to claim 1, characterized in that, When the molten iron contains 0.08-0.15% titanium, 0.4-0.6% silicon + titanium, has a physical heat of 1460-1490℃, a blast furnace permeability index of 16.5-18.5%, a comprehensive ore grade ≥55%, a blast furnace zinc load ≥1300g / t, a blast furnace alkali metal load ≥3kg / t, a blast furnace titanium load ≥17kg / t, coke thermal reactivity ≤45%, coke post-reaction strength ≥48%, and zinc deposition ≤15t, while also meeting the requirements of good slag fluidity, uniform charging within the furnace, and a stable charging rate of 7-8 batches / h, the furnace is operating normally. The following operations are performed: control the slag basicity R2 to 1.05-1.15 times, the furnace top pressure to 195 kPa, the hot blast pressure to 370 kPa, the oxygen enrichment rate to 5%, the taphole depth to 2900 mm, the water temperature difference in the blast furnace waist to 0.8-1.2℃, the water temperature difference in the lower part of the blast furnace body to 2.0-3.0℃, and the water temperature difference in the middle part of the blast furnace body to 3-5℃. Adjust the blast furnace gas flow distribution to maintain smooth central gas flow while ensuring stable edge gas flow. Control the central temperature to 350-450℃ and the edge temperature to 100-150℃. Boost the gas utilization rate towards the upper limit and control the fuel ratio towards the lower limit to ensure qualified molten iron quality.

3. The smelting method for vanadium-titanium iron ore with high levels of harmful elements according to claim 1, characterized in that, When the titanium content in molten iron is 0.1-0.2%, the silicon + titanium content in molten iron is 0.45-0.65%, the physical heat of molten iron is 1460-1500℃, the blast furnace permeability index is 16.5-18.5%, the overall grade of ore fed into the furnace is ≥55%, the zinc load in the blast furnace is ≥1300g / t, the alkali metal load in the blast furnace is ≥3kg / t, the titanium load in the blast furnace is ≥17kg / t, the thermal reactivity of coke is ≤45%, the strength of coke after reaction is ≥48%, the amount of zinc element deposited in the blast furnace is ≥15t, and at the same time, the slag fluidity is generally good, the charging in the furnace is uneven, the charging rate fluctuates at 6-8 batches / h, and the furnace condition shows slight fluctuations, then the following operations should be performed: control The slag basicity R2 is 1.0-1.1 times, 200 kg of magnesite is added to the batch, the magnesium-aluminum ratio in the slag is ≥0.6 times, the furnace top pressure is 185 kPa, the hot blast pressure is 360 kPa, the oxygen enrichment rate is 3.5%, the taphole depth is 2800 mm, the water temperature difference in the blast furnace waist is 1.0-2.0℃, the water temperature difference in the lower part of the blast furnace body is 3-4℃, and the water temperature difference in the middle part of the blast furnace body is 4-6℃. The blast furnace gas flow distribution is adjusted to guide the edge gas flow while ensuring the stability of the center gas flow. The center temperature is controlled at 300-400℃, the edge temperature is 150-200℃, the gas utilization rate is close to the middle limit, the fuel ratio is controlled at the middle limit, and the quality of molten iron is guaranteed to be qualified.

4. The smelting method for vanadium-titanium iron ore with high levels of harmful elements according to claim 1, characterized in that, When the molten iron contains 0.15-0.2% titanium, 0.5-0.65% silicon + titanium, has a physical heat of 1470-1500℃, a blast furnace permeability index of 16.5-18.5%, a comprehensive ore grade ≥55%, a blast furnace zinc load ≥1300g / t, a blast furnace alkali metal load ≥3kg / t, a blast furnace titanium load ≥17kg / t, coke thermal reactivity ≤45%, coke post-reaction strength ≥48%, and zinc deposition in the blast furnace ≥30t, while simultaneously meeting the following conditions: slag fluidity is generally good, but uneven charging and slippage occur, with material rate fluctuations of 5-8 batches / h, resulting in significant fluctuations in furnace conditions, the following operations should be performed: Control The slag basicity R2 is 0.9-1.0 times. 200 kg of fluorite and 150 kg of manganese ore are added to the batch. The furnace top pressure is controlled at 180 kPa, the hot blast pressure at 355 kPa, the oxygen enrichment rate at 2.5%, the taphole depth at 2700 mm, the water temperature difference at the blast furnace waist at 1.5-2.5℃, the water temperature difference at the lower part of the blast furnace body at 3.5-5.5℃, and the water temperature difference at the middle part of the blast furnace body at 4-8℃. The blast furnace gas flow distribution is adjusted to narrow the charging platform, strongly developing both central and edge airflows. The central temperature is controlled at 400-500℃, and the edge temperature at 150-250℃. The gas utilization rate is brought closer to the lower limit, and the fuel ratio is controlled towards the upper limit to ensure qualified molten iron quality.

5. The smelting method for vanadium-titanium iron ore with high levels of harmful elements according to claim 1, characterized in that, When the titanium content in molten iron is 0.15-0.2%, the silicon + titanium content in molten iron is 0.5-0.65%, the physical heat of molten iron is 1475-1500℃, the blast furnace permeability index is 16.5-18.5%, the overall grade of ore fed into the furnace is ≥55%, the zinc load in the blast furnace is ≥1300g / t, the alkali metal load in the blast furnace is ≥3kg / t, the titanium load in the blast furnace is ≥17kg / t, the thermal reactivity of coke is ≤45%, the strength of coke after reaction is ≥48%, the zinc deposition in the blast furnace is ≥50t, and at the same time, the slag fluidity is generally good, the charging in the furnace is uneven and produces slippage, collapse and hanging phenomena, and the material rate fluctuates at 4-8 batches / h, and the furnace conditions fluctuate significantly, then the following operations should be performed: control the slag basicity. R2 is 0.9-1.0 times, with 300kg of fluorite and 250kg of manganese ore added to the batch. The ore and coke load is reduced by 0.1-0.2 times, the material line is lowered to 2-3m, the furnace top pressure is 170KPa, the hot blast pressure is 345KPa, the oxygen enrichment rate is 0%, the taphole depth is 2700mm, the water temperature difference in the blast furnace waist is 2.5-3.5℃, the water temperature difference in the lower part of the blast furnace body is 5-7℃, and the water temperature difference in the middle part of the blast furnace body is 6-10℃. The blast furnace gas flow distribution is adjusted to strongly guide the edge airflow to ensure smooth material feeding while reducing the proportion of ore and coke in the center. The center temperature is controlled at 300-400℃, the edge temperature is 180-250℃, the lower limit of gas utilization rate and the upper limit of fuel ratio are controlled to ensure the quality of molten iron is qualified.

6. The smelting method for vanadium-titanium iron ore with high levels of harmful elements according to claim 1, characterized in that, When selecting the fabric matrix, the initial α angle of the fabric should be 1-2° smaller than the angle at the point of impact, and the fabric line depth should be 300-500mm lower than the normal fabric line depth.

7. The smelting method for vanadium-titanium iron ore with high levels of harmful elements according to claim 1, characterized in that, The number of types of coke fed into the furnace should be less than 3, the proportion of heat-strength coke should be greater than 60%, the basicity qualification rate of the ore fed into the furnace should be greater than 98%, and the powder rate should be less than 5%.

8. The smelting method for vanadium-titanium iron ore with high levels of harmful elements according to claim 1, characterized in that, Maintain a stable blast furnace thermal regime, ensure that the slag and iron PT value is ≥1480℃, raise the top temperature to ≥180℃ as the benchmark for zinc removal, and ensure that the zinc content in gas ash is not less than 17.5%.