Method for reducing charging sulfur load of schreyerite smelting blast furnace

Abstract

The invention relates to the technical field of metallurgy, in particular to a method for reducing charging sulfur load of a schreyerite smelting blast furnace. Comprising the following steps that sintered ore, pellet ore, raw ore, coke and pulverized coal are mixed and then fed into a furnace, sulfur-containing steelmaking sludge is added into the pellet ore, and gravity ash and cyclone ash are added into the sintered ore. According to the method, ore blending is optimized, so that the sulfur content in pellets and sinter is effectively reduced, and the sulfur load in a furnace is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgy, in particular to a method for reducing the sulfur load of a vanadium-titanium ore smelting blast furnace. Background Art

[0002] The blast furnace is one of the most critical pieces of equipment in the ironmaking process, and its performance directly impacts the quality of the molten iron and production efficiency. The comprehensive charge grade is a key indicator for evaluating blast furnace performance. This refers to the average composition of the charge in the blast furnace hearth, essentially the quality of the blast furnace charge ore. The quality of the blast furnace charge ore directly affects the composition of the slag, the composition of the molten iron, and its temperature, which in turn influences the slag's fluidity, chemical properties, and dephosphorization capacity, ultimately impacting the quality of the molten iron. Improving the comprehensive charge grade is crucial to the production efficiency of an ironworks.

[0003] Sulfur load refers to the total amount of sulfur contained in the raw materials entering the blast furnace, which comes from both organic and inorganic sulfur. In the blast furnace, sulfur reacts with iron, trace elements, and other elements to form low-melting-point sulfides, which affect the fluidity of the slag and reduce the furnace's smelting efficiency. High-sulfur raw materials entering the blast furnace produce large amounts of harmful gases such as SO2, increasing emissions, the environmental burden, and the difficulty of remediation. Sulfur is a harmful element in ferroalloys, reducing the toughness and ductility of steel and its quality.

[0004] Blast furnace ironmaking is a core component of the modern steel industry. Its smelting efficiency, environmental burden, and steel quality are directly related to the production benefits and market competitiveness of steel companies. However, blast furnace smelting often faces problems such as low raw material grade and high sulfur load. These problems not only reduce blast furnace smelting efficiency, but also increase the environmental burden and affect steel quality. Therefore, developing a method to effectively reduce the sulfur load entering the furnace during the vanadium-titanium ore smelting process is of great significance for improving blast furnace smelting standards and promoting the green development of the steel industry. Summary of the Invention

[0005] To address the shortcomings of the prior art, the present invention provides a method for reducing the sulfur load of a vanadium-titanium ore smelting blast furnace. The present invention optimizes ore blending to effectively reduce the sulfur content in pellets and sintered ore, thereby reducing the sulfur load of the blast furnace.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention provides a method for reducing the sulfur load of a vanadium-titanium ore smelting blast furnace, comprising the following steps:

[0008] Sintered ore, pelletized ore, green ore, coke and coal powder are mixed and put into a furnace, wherein sulfur-containing steelmaking sludge is added to the pelletized ore, and gravity ash and cyclone ash are added to the sintered ore.

[0009] Preferably, the sulfur content of the sulfur steelmaking sludge is 1-2%.

[0010] Preferably, the mass of the sulfur-containing steelmaking sludge accounts for 2% of the mass of the pellets.

[0011] Preferably, the total mass of the gravity ash and cyclone ash accounts for 2% of the mass of the sintered ore.

[0012] Preferably, the chemical composition of the sintered ore includes, by mass content: TFe 52.1-52.2%, TiO2 3.5-4.5%, FeO 7-9%, V2O5 0.35-0.5%, S 0.09%, and a basicity of 2.55.

[0013] Preferably, the chemical composition of the pellets includes, by mass content: TFe 50-55%, FeO 1-2%, V2O5 0.5-0.6%, and TiO2 8-10%.

[0014] Preferably, the chemical composition of the raw ore includes, by mass content: TFe 58-60%, S 0.15%.

[0015] Preferably, the particle size of the raw ore is 10-40 mm.

[0016] Preferably, the fixed carbon of the coke is ≥85.5%, and S is ≤0.85%.

[0017] Preferably, the fixed carbon of the pulverized coal is ≥78%, and S is ≤0.7%.

[0018] Preferably, the mass ratio of the sintered ore, pelletized ore and raw ore is 47:50:3.

[0019] Preferably, the amount of coke added is 380-390 kg / ton of iron.

[0020] Preferably, the amount of coal powder added is 160-170 kg / ton of iron.

[0021] Preferably, the temperature of the molten iron in smelting the vanadium-titanium ore is 1430-1460°C.

[0022] Preferably, the slag temperature of the vanadium-titanium ore smelting is 1450-1480°C.

[0023] Preferably, the air supply system for vanadium-titanium ore smelting is full air temperature operation, maintained above 1200°C, and oxygen enrichment: 12000m 3 / h.

[0024] Preferably, the slag-making system for vanadium-titanium ore smelting is to ensure that the binary basicity of the slag is 1.05-1.10, the ternary basicity is 1.42-1.45, the magnesium-aluminum ratio is 0.62-0.65%, and the titanium dioxide content in the slag is 21.5-23%.

[0025] The beneficial effects of the present invention are:

[0026] The key to reducing the sulfur load lies in the rational selection of furnace charge. The selection of furnace charge needs to consider factors such as the grade, particle size, sintering performance and combustion performance of the furnace charge. The present invention optimizes the furnace charge structure, adds sulfur-containing steelmaking sludge to the pelletized ore, and utilizes the high temperature and strong oxidizing atmosphere in the pellet production process to remove more than 90% of the sulfur. Gravity ash and cyclone ash are added to the sintered ore, and the unburned coke powder / coal powder (sulfur content of about 0.85) in the gravity ash and cyclone ash are burned and removed by high-temperature combustion during the exhaust sintering process, thereby reducing the sulfur content of the sintered ore and further reducing the sulfur load entering the furnace. In addition, the operation of the blast furnace is also optimized. The operation of the blast furnace includes the input of furnace charge, the adjustment of the tuyere, the treatment of slag, etc. The present invention reduces the rate at which sulfur forms sulfides in the blast furnace by rationally controlling the parameters such as the furnace temperature, gas volume, and material capacity of the blast furnace, and ultimately achieves the goal of improving the comprehensive blast furnace entry grade and reducing the sulfur load. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand the technical solution of the invention, the present invention is further described in detail below in conjunction with specific implementation methods.

[0028] In order to effectively reduce the sulfur content in pellets and sintered ore and reduce the sulfur load entering the furnace, the present invention provides a method for reducing the sulfur load entering a vanadium-titanium ore smelting blast furnace, comprising the following steps:

[0029] Sintered ore, pelletized ore, green ore, coke and coal powder are mixed and put into a furnace, wherein sulfur-containing steelmaking sludge is added to the pelletized ore, and gravity ash and cyclone ash are added to the sintered ore.

[0030] Among them, sulfur-containing steelmaking sludge is solid waste formed after precipitation and dehydration of sulfur-containing wastewater generated in the steelmaking process in this field. Its main components are iron oxides (FeO, Fe2O2), calcium compounds (CaO, CaSO2), sulfides (such as FeS) and trace heavy metals.

[0031] Gravity ash: Coarse dust particles collected by gravity settling chambers during the sintering or coking process in steel plants. Particle size is typically greater than 50 μm. The main components are unburned carbon, iron oxides, CaO, MgO, and small amounts of alkali metals.

[0032] Cyclone ash: Medium-sized dust separated by a cyclone dust collector, with a particle size range of 10 to 50 μm. Its composition is similar to that of gravity ash (iron, carbon, CaO, etc.), but it has a finer particle size and a larger specific surface area. The sulfur and chlorine content may be slightly higher (due to the adsorption of gaseous pollutants).

[0033] The sulfur content of the sulfur steelmaking sludge of the present invention is 1-2%. The mass of the sulfur-containing steelmaking sludge accounts for 2% of the mass of the pellets. After being added, more than 90% of the sulfur is removed by utilizing the high temperature and strong oxidizing atmosphere during the pellet production process.

[0034] The present invention only requires ensuring that the combined mass of the gravity ash and cyclone ash accounts for 2% of the mass of the sintered ore, without requiring a fixed amount of gravity ash and cyclone ash. This allows the high-temperature combustion during the draft sintering process to combust and remove unburned coke and coal dust (sulfur content of approximately 0.85%) from the gravity ash and cyclone ash, thereby reducing the sulfur content of the sintered ore and further reducing the sulfur load entering the furnace.

[0035] The chemical composition of the sintered ore of the present invention comprises, by mass content, TFe 52.1-52.2%, TiO2 3.5-4.5%, FeO 7-9%, V2O5 0.35-0.5%, S 0.09%, and a basicity of 2.55.

[0036] The chemical composition of the pellets of the present invention comprises, by mass content, 50-55% of TFe, 1-2% of FeO, 0.5-0.6% of V2O5, and 8-10% of TiO2.

[0037] The chemical composition of the raw ore of the present invention includes, by mass content, TFe 58-60% and S 0.15%.

[0038] The particle size of the raw ore of the present invention is 10-40 mm.

[0039] The fixed carbon of the coke of the present invention is ≥85.5%, and S is ≤0.85%.

[0040] The fixed carbon of the pulverized coal of the present invention is ≥78%, and S is ≤0.7%.

[0041] The mass ratio of the sintered ore, pelletized ore and raw ore in the present invention is 47:50:3.

[0042] The amount of coke added in the present invention is 380-390 kg per ton of iron.

[0043] The amount of coal powder added in the present invention is 160-170 kg per ton of iron.

[0044] The operation of a blast furnace includes charging of furnace charge, adjustment of tuyere, treatment of slag, etc. The present invention reduces the rate at which sulfur forms sulfides in the blast furnace by rationally controlling parameters such as furnace temperature, gas volume, and material capacity, thereby ultimately improving the comprehensive charging grade of the blast furnace and reducing the sulfur load.

[0045] The temperature of the molten iron in smelting the vanadium-titanium ore of the present invention is 1430-1460°C.

[0046] The slag temperature of the vanadium-titanium ore smelting of the present invention is 1450-1480°C.

[0047] The air supply system for vanadium-titanium ore smelting of the present invention operates at full air temperature, maintained above 1200°C, and oxygen enrichment: 12000m 3 / h.

[0048] The slag making system for vanadium-titanium ore smelting of the present invention is as follows: ensuring that the binary basicity of the slag is 1.05-1.10, the ternary basicity is 1.42-1.45, the magnesium-aluminum ratio is 0.62-0.65%, and the titanium dioxide content in the slag is 21.5-23%.

[0049] Example 1

[0050] (1) Raw material selection and pretreatment:

[0051] Sintered ore: by mass content: TFe 52.1%, TiO2 3.5%, FeO 7%, V2O5 0.35%, S 0.09%, basicity 2.55.

[0052] Pellets: by mass content: TFe 50%, FeO 1%, V2O5 0.5%, TiO2 8%.

[0053] Raw ore: by mass content: TFe 58%, S 0.15%; the raw ore is screened to a particle size of 10 mm.

[0054] Coke: fixed carbon ≥85.5%, S ≤0.85%.

[0055] Pulverized coal: fixed carbon ≥78%, S ≤0.7%.

[0056] (2) Optimize the charge structure:

[0057] Sintered ore, pelletized ore and raw ore are mixed in a mass ratio of 47:50:3, coke is loaded from the furnace top (coke ratio is controlled at 380kg / ton iron), and pulverized coal is sprayed into the furnace through the tuyere (coal ratio is controlled at 160kg / ton iron) to form a stable charge structure. At the same time, according to the actual operation of the blast furnace, the charging system of the charge is adjusted in time to match the permeability of the upper and lower parts of the blast furnace.

[0058] (3) Optimize ore blending: ① Add 2% by weight of high-sulfur (sulfur content 1.2%) steelmaking sludge to pellet ore for production, and use the high temperature and strong oxidizing atmosphere in the pellet production process to remove more than 90% of the sulfur; ② Add 2% by weight of gravity ash and cyclone ash to sintered ore powder, and use the high temperature combustion during the exhaust sintering process to burn and remove the unburned coke powder / coal powder (sulfur content of about 0.85) in the gravity ash and cyclone ash, thereby reducing the sulfur content of the sintered ore and further reducing the sulfur load entering the furnace.

[0059] (4) Optimize smelting operations:

[0060] Blast furnace thermal system:

[0061] a. Molten iron temperature: 1430℃.

[0062] b. Slag temperature: 1450℃.

[0063] c.

Si

Ti

[0064] Air supply system:

[0065] a. Operate at full air temperature, maintaining above 1200℃.

[0066] b. The coal injection ratio is maintained at 160kg / tFe.

[0067] c. Oxygen enrichment: 12000m 3 / h.

[0068] Slag making system

[0069] The binary basicity of the slag is guaranteed to be 1.05-1.10, the ternary basicity is 1.42-1.45, the magnesium-aluminum ratio is 0.62-0.65%, and the titanium dioxide content in the slag is 21.5-23%.

[0070] Adjust the above parameters appropriately based on the actual blast furnace operation to ensure stable and efficient operation. Simultaneously, utilize automated control systems and intelligent monitoring technologies to monitor various parameters and indicators during the blast furnace smelting process in real time, promptly identifying and addressing abnormalities. Ensure slag basicity of 1.05-1.10, magnesium-aluminum ratio of 0.62-0.65%, and titanium dioxide content of 21.5-23% to ensure fluidity and normal slag-iron discharge. Slag is the primary destination of sulfur in the blast furnace, so the slag's desulfurization capacity must be fully utilized to ensure both sulfur content and fluidity, thereby ensuring that the molten iron meets acceptable standards.

[0071] Example 2

[0072] (1) Raw material selection and pretreatment:

[0073] Sintered ore: by mass content: TFe 52.2%, TiO2 4.5%, FeO 9%, V2O5 0.5%, S 0.09%, basicity 2.55.

[0074] Pellets: by mass content: TFe 55%, FeO 2%, V2O5 0.6%, TiO2 10%.

[0075] Raw ore: by mass content: TFe 60%, S 0.15%; the raw ore is screened to a particle size of 40 mm.

[0076] Coke: fixed carbon ≥85.5%, S ≤0.85%.

[0077] Pulverized coal: fixed carbon ≥78%, S ≤0.7%.

[0078] (2) Optimize the charge structure:

[0079] Sintered ore, pelletized ore and raw ore are mixed in a mass ratio of 47:50:3, coke is loaded from the furnace top (coke ratio is controlled at 390kg / ton iron), and pulverized coal is sprayed into the furnace through the tuyere (coal ratio is controlled at 170kg / ton iron) to form a stable charge structure. At the same time, according to the actual operation of the blast furnace, the charging system of the charge is adjusted in time to match the permeability of the upper and lower parts of the blast furnace.

[0080] (3) Optimize ore blending: ① Add 2% by weight of high-sulfur (sulfur content 1.2%) steelmaking sludge to pellet ore for production, and use the high temperature and strong oxidizing atmosphere in the pellet production process to remove more than 90% of the sulfur; ② Add 2% by weight of gravity ash and cyclone ash to sintered ore powder, and use the high temperature combustion during the exhaust sintering process to burn and remove the unburned coke powder / coal powder (sulfur content of about 0.85) in the gravity ash and cyclone ash, thereby reducing the sulfur content of the sintered ore and further reducing the sulfur load entering the furnace.

[0081] (4) Optimize smelting operations:

[0082] Blast furnace thermal system:

[0083] a. Molten iron temperature: 1460℃.

[0084] b. Slag temperature: 1480℃.

[0085] c. [Si], [Ti] control: 0.4.

[0086] Air supply system:

[0087] a. Operate at full air temperature, maintaining above 1200℃.

[0088] b. The coal injection ratio is maintained at 170kg / tFe.

[0089] c. Oxygen enrichment: 12000m 3 / h.

[0090] Slag making system

[0091] The binary basicity of the slag is guaranteed to be 1.05-1.10, the ternary basicity is 1.42-1.45, the magnesium-aluminum ratio is 0.62-0.65%, and the titanium dioxide content in the slag is 21.5-23%.

[0092] Adjust the above parameters appropriately based on the actual blast furnace operation to ensure stable and efficient operation. Simultaneously, utilize automated control systems and intelligent monitoring technologies to monitor various parameters and indicators during the blast furnace smelting process in real time, promptly identifying and addressing abnormalities. Ensure slag basicity of 1.05-1.10, magnesium-aluminum ratio of 0.62-0.65%, and titanium dioxide content of 21.5-23% to ensure fluidity and normal slag-iron discharge. Slag is the primary destination of sulfur in the blast furnace, so the slag's desulfurization capacity must be fully utilized to ensure both sulfur content and fluidity, thereby ensuring that the molten iron meets acceptable standards.

[0093] Effect:

[0094] ① High-sulfur steelmaking sludge is added to pelletizing ore for production, utilizing the high temperature and strong oxidizing atmosphere of the pelletizing process to remove over 90% of the sulfur in the steelmaking sludge. ② Gravity ash and cyclone ash are added to sintered ore powder, and the unburned coke and coal powder (sulfur content of approximately 0.85%) in the gravity ash and cyclone ash are burned and removed during the high-temperature exhaust sintering process, thereby reducing the sulfur content of the sintered ore to less than 0.1% and the sulfur load entering the furnace to less than 5.5kg. Within the blast furnace slag basicity range of 1.05-1.10, the desulfurization distribution coefficient reaches over 6.0, thereby controlling the sulfur content of the molten iron to less than 0.130%.

[0095] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be construed as limiting the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. Persons skilled in the art will appreciate that improvements and modifications may be made without departing from the spirit and scope of the present invention, and such improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for reducing the sulfur load of a vanadium-titanium ore smelting blast furnace, characterized in that: The following steps are involved: Sintered ore, pelletized ore, green ore, coke and coal powder are mixed and put into a furnace, wherein sulfur-containing steelmaking sludge is added to the pelletized ore, and gravity ash and cyclone ash are added to the sintered ore.

2. The method for reducing the sulfur load of a vanadium-titanium ore smelting blast furnace according to claim 1, characterized in that: The sulfur content of the sulfur steelmaking sludge is 1-2%.

3. The method for reducing the sulfur load of a vanadium-titanium ore smelting blast furnace according to claim 1 or 2, characterized in that: The mass of the sulfur-containing steelmaking sludge accounts for 2% of the mass of the pellets.

4. The method for reducing the sulfur load of a vanadium-titanium ore smelting blast furnace according to claim 1, characterized in that: The total mass of the gravity ash and cyclone ash accounts for 2% of the mass of the sintered ore.

5. The method for reducing the sulfur load of a vanadium-titanium ore smelting blast furnace according to claim 1, characterized in that: The chemical composition of the sintered ore includes, by mass content, TFe 52.1-52.2%, TiO2 3.5-4.5%, FeO7-9%, V2O5 0.35-0.5%, S 0.09%, and a basicity of 2.

55.

6. The method for reducing the sulfur load of a vanadium-titanium ore smelting blast furnace according to claim 1, characterized in that: The chemical composition of the pellets includes, by mass content, 50-55% of TFe, 1-2% of FeO, 0.5-0.6% of V2O5, and 8-10% of TiO2.

7. The method for reducing the sulfur load of a vanadium-titanium ore smelting blast furnace according to claim 1, characterized in that: The chemical composition of the raw ore includes, by mass content, TFe 58-60%, and S 0.15%.

8. The method for reducing the sulfur load of a vanadium-titanium ore smelting blast furnace according to claim 7, characterized in that: The particle size of the raw ore is 10-40 mm.

9. The method for reducing the sulfur load of a vanadium-titanium ore smelting blast furnace according to claim 1, characterized in that: The temperature of the molten iron in smelting the vanadium-titanium ore is 1430-1460°C.

10. The method for reducing the sulfur load of a vanadium-titanium ore smelting blast furnace according to claim 1, characterized in that: The slag temperature of the vanadium-titanium ore smelting is 1450-1480°C.