Method for improving vanadium reduction rate of molten iron in blast furnace smelting of chromium-containing vanadium titano-magnetite

Abstract

The invention provides a method for improving the vanadium reduction rate of molten iron in blast furnace smelting of chromium-containing vanadium-titanium magnetite, which comprises the following steps: feeding chromium-containing vanadium-titanium magnetite sinter and chromium-containing vanadium-titanium magnetite pellets as charging materials into a blast furnace for smelting, controlling the temperature of the blast furnace molten iron to be 1400-1550 DEG C, and controlling the components of the blast furnace molten iron and slag components, thereby improving the vanadium reduction rate of the molten iron. And the blast furnace is stable in furnace condition and good in slag fluidity.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgy, in particular to a method for improving the vanadium reduction rate of molten iron by blast furnace smelting of chromium-containing vanadium-titanium magnetite. Background Art

[0002] Vanadium is an important recovery element in the blast furnace smelting of vanadium-titanium magnetite. Improving the vanadium reduction rate in hot metal can increase the vanadium content in pig iron without increasing the input of vanadium resources, thereby increasing the output of vanadium products. The main production control difficulties in vanadium-titanium magnetite smelting are as follows:

[0003] (1) The strength of vanadium-titanium sintered ore is poor, and low-temperature reduction causes serious pulverization, which affects the permeability of the blast furnace and affects the smooth operation of the blast furnace;

[0004] (2) The slag iron has high viscosity and poor fluidity, which affects the working state of the furnace and the vanadium reduction rate of the molten iron;

[0005] (3) As the V content of molten iron increases, especially when the V content of molten iron increases to above 0.33%, the TiO2 content in the corresponding slag increases from less than 10% to 13-16%, the iron loss increases, and the vanadium reduction rate decreases.

[0006] CN106636506A discloses a blast furnace smelting method for vanadium-titanium magnetite. The method includes: a) obtaining limestone, crushing it, and grinding it to obtain limestone powder; b) preparing the ingredients according to the following weight ratio: iron concentrate: limestone powder: dust ash = 200-400: 1.5-4: 1.5-3, and adjusting the slag basicity to 1.4-1.7; c) mixing the limestone powder and dust ash, spraying them into the blast furnace combustion zone through a blast furnace side tuyere branch pipe, and calcining them at 900-1100°C for 40-60 minutes; d) cooling the calcined material in step c to room temperature, removing it, crushing it, and grinding it to obtain vanadium-titanium magnetite powder. Using dust ash and limestone powder, the blast furnace calcination and reduction method reduces impurities in the vanadium-titanium magnetite, promotes resource recycling, and improves the iron grade of the vanadium-titanium magnetite.

[0007] CN102220440A discloses a vanadium-titanium magnetite blast furnace smelting method for improving vanadium yield. The method comprises mixing coke (10-20% of the total coke charge) with sintered ore and adding the mixture together with vanadium-titanium pellets into a blast furnace to form ore layers. The ore layers and coke layers are arranged alternately. The coke layers contain 80-90% of the total coke charge, the sintered ore accounts for 55-65% of the total ore weight, and the vanadium-titanium pellets account for 35-45% of the total ore weight. This method effectively improves the vanadium yield during the vanadium-titanium magnetite blast furnace smelting process, while also accelerating iron reduction and increasing the smelting intensity and output of the blast furnace.

[0008] CN104060007A discloses a method for smelting vanadium-titanium magnetite in a blast furnace. The method comprises: during the smelting process of the vanadium-titanium magnetite in a blast furnace, injecting fuel and fluorite powder into the blast furnace through a tuyere, wherein the weight ratio of the fuel to the fluorite powder is 1:(0.01-0.05), and the particle size of the fluorite powder is less than 0.1 mm; the carrier gas used for injecting the fuel and fluorite powder is compressed air, and the temperature of the compressed air is 10-25°C and the pressure is 800-1200 kPa. Injecting fuel and fluorite powder into the blast furnace through the tuyere not only improves the utilization rate of the fluorite powder, but also prevents a large amount of lumpy fluorite added from the furnace top from occupying the effective space of the blast furnace and absorbing a large amount of heat. The fluorite powder injected from the tuyere will directly react with the vanadium-titanium slag, improving the properties of the slag and achieving better separation of slag and iron, thereby achieving the purpose of reducing iron in the slag and reducing the fuel ratio.

[0009] However, the above-mentioned method for smelting vanadium-titanium magnetite in a blast furnace still has problems such as poor slag fluidity and low vanadium reduction rate in blast furnace molten iron. Summary of the Invention

[0010] In view of the problems existing in the prior art, the present invention provides a method for improving the vanadium reduction rate of molten iron in blast furnace smelting of chromium-containing vanadium-titanium magnetite. The method controls the blast furnace molten iron temperature, blast furnace molten iron composition and slag composition, so as to achieve a significant increase in the vanadium reduction rate of the molten iron while stabilizing the blast furnace condition and improving the slag fluidity.

[0011] To achieve this object, the present invention adopts the following technical solutions:

[0012] The present invention provides a method for improving the vanadium reduction rate of molten iron by blast furnace smelting of chromium-containing vanadium-titanium magnetite, the method comprising:

[0013] Chromium-containing vanadium-titanium magnetite sintered ore and chromium-containing vanadium-titanium magnetite pellets are fed into a blast furnace for smelting, and the temperature of the blast furnace molten iron is controlled at 1400-1550° C. to obtain blast furnace molten iron with a high vanadium reduction rate.

[0014] The method for improving the vanadium reduction rate of molten iron by blast furnace smelting of chromium-containing vanadium-titanium magnetite is rationally designed. The method uses chromium-containing vanadium-titanium magnetite sinter and chromium-containing vanadium-titanium magnetite pellets as feed materials for blast furnace smelting. Furthermore, the temperature, composition, and slag composition of the molten iron are controlled to achieve physical and chemical thermal control of the molten iron, ensuring good slag fluidity. Without increasing the input of vanadium resources, blast furnace iron with a vanadium reduction rate of over 89% is obtained. The method controls the temperature of the molten iron to 1400-1550°C to ensure good fluidity. When the molten iron temperature is high, carbon deposition occurs during the subsequent cooling process, causing the molten iron to rapidly become sticky and deteriorate in fluidity, which can seriously affect subsequent processing steps.

[0015] The temperature of the molten iron in the blast furnace of the present invention is 1400-1550°C, for example, it can be 1400°C, 1420°C, 1460°C, 1500°C or 1550°C, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable.

[0016] Preferably, the chromium-containing vanadium-titanium magnetite sintered ore is sintered by sintering a first chromium-containing vanadium-titanium magnetite powder and an external ore powder.

[0017] The present invention does not limit the specific preparation method of the chromium-containing vanadium-titanium magnetite sintered ore, and the sintering method of magnetite powder commonly used in the art can be used for preparation.

[0018] Preferably, the external mineral powder accounts for 8% to 15% of the total material mass, for example, it can be 8%, 9.2%, 10.5%, 12%, 13.8% or 15%, etc., but is not limited to the listed values. Other values ​​not listed within this numerical range are also applicable.

[0019] When preparing chromium-containing vanadium-titanium magnetite sintered ore, the present invention preferably uses external ore powder at 8% to 15% of the total material mass, which has the advantages of improving the permeability of the sintered material layer and increasing the hourly output. Adding more external ore powder reduces the vanadium content of the sintered ore; adding less external ore powder reduces the sintering output and quality.

[0020] Preferably, the first chromium-containing vanadium-titanium magnetite powder includes TFe in a mass percentage of 62% to 63%, for example, 62%, 62.2%, 62.4%, 62.6%, 62.8% or 63%, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0021] CaO: 2% to 2.5%, for example, 2%, 2.1%, 2.2%, 2.3%, 2.4% or 2.5%, but is not limited to the values ​​listed above, and other values ​​not listed within the range are also applicable;

[0022] MgO: 1.5% to 1.8%, for example, 1.5%, 1.55%, 1.6%, 1.65%, 1.7% or 1.8%, but is not limited to the values ​​listed above. Other values ​​not listed within this range are also applicable;

[0023] SiO2: 5% to 5.3%, for example, 5%, 5.1%, 5.15%, 5.2%, 5.25% or 5.3%, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0024] Al2O3: 1.2% to 1.5%, for example, 1.2%, 1.25%, 1.3%, 1.35%, 1.4% or 1.5%, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0025] TiO2: 1.5% to 2%, for example, 1.5%, 1.6%, 1.7%, 1.8%, 1.9% or 2%, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0026] V2O5: 0.2% to 0.6%, for example, 0.2%, 0.3%, 0.4%, 0.45%, 0.55% or 0.6%, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0027] P: 0.01% to 0.02%, for example, it can be 0.01%, 0.012%, 0.014%, 0.016%, 0.018% or 0.02%, etc., but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0028] Cr2O3: 0.1% to 0.13%, for example, it can be 0.10%, 0.105%, 0.11%, 0.115%, 0.125% or 0.13%, etc., but it is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0029] Preferably, the external mineral powder includes TFe: 63% to 65%, for example, 63%, 63.5%, 64%, 64.2%, 64.8% or 65%, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0030] CaO: 1.3% to 1.5%, for example, 1.3%, 1.35%, 1.38%, 1.42%, 1.45% or 1.5%, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0031] MgO: 2% to 2.3%, for example, 2%, 2.05%, 2.1%, 2.15%, 2.2% or 2.3%, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0032] SiO2: 5% to 6%, for example, 5%, 5.1%, 5.3%, 5.5%, 5.7% or 6%, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0033] Al2O3: 0.5% to 1%, for example, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0034] TiO2: 0.2% to 0.25%, for example, 0.20%, 0.21%, 0.22%, 0.23%, 0.24% or 0.25%, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0035] V2O5: 0.3% to 0.5%, for example, 0.30%, 0.35%, 0.40%, 0.43%, 0.47% or 0.50%, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0036] P: 0.06% to 0.1%, for example, it can be 0.06%, 0.07%, 0.08%, 0.085%, 0.095% or 0.1%, etc., but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0037] Preferably, the TiO2 content in the chromium-containing vanadium-titanium magnet sintered ore is less than 2.2%, for example, it can be 2.1%, 2%, 1.8%, 1.5%, 1.3%, 1% or 0.5%, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0038] The present invention preferably contains TiO2 less than 2.2% in the chromium-containing vanadium-titanium magnet sintered ore to ensure the quality of the vanadium-titanium sintered ore and the vanadium content of the sintered ore.

[0039] Preferably, the binary basicity of the chromium-containing vanadium-titanium magnetite sintered ore is 1.9 to 2.3, for example, it can be 1.9, 2.0, 2.1, 2.2 or 2.3, but is not limited to the listed values. Other values ​​not listed within this numerical range are also applicable.

[0040] The present invention preferably uses a binary basicity of 1.9 to 2.3 for the chromium-containing vanadium-titanium magnetite sintered ore to ensure good sintered ore performance. Lower binary basicities result in insufficient sintering liquid phase, which can degrade sintered physicochemical properties. Higher binary basicities can make the slag viscous, impair fluidity, and potentially cause furnace hearth accumulation. Furthermore, the slag melting point increases, increasing fuel consumption.

[0041] Preferably, the drum strength of the chromium-containing vanadium-titanium magnetite sintered ore is ≥80%, for example, it can be 80%, 82%, 84%, 85%, 87%, 89% or 90%, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0042] Preferably, the RDI+3.15 of the chromium-containing vanadium-titanium magnetite sintered ore is ≥90%, for example, it can be 90%, 92%, 93%, 94%, 95%, 96% or 97%, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0043] The RDI+3.15 mentioned in the present invention is a professional term in this field, which refers to the low-temperature reduction powdering index.

[0044] Preferably, the chromium-containing vanadium-titanium magnetite pellets are obtained by granulating and molding a second chromium-containing vanadium-titanium magnetite powder.

[0045] The present invention does not limit the specific preparation method of the chromium-containing vanadium-titanium magnetite pellets, and can be prepared by granulating and molding magnetite powder commonly used in the art. The particle size of the chromium-containing vanadium-titanium magnetite pellets is 8 to 16 mm, for example, 8 mm, 9 mm, 10 mm, 12 mm, 15 mm, or 16 mm, but is not limited to the listed values. Other values ​​not listed within this numerical range are also applicable.

[0046] Preferably, the second chromium-containing vanadium-titanium magnetite powder includes TFe in a mass percentage of 58% to 60%, for example, 58%, 58.3%, 58.7%, 59.2%, 59.6% or 60%, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0047] CaO: 0.7% to 0.8%, for example, 0.7%, 0.72%, 0.74%, 0.76%, 0.78% or 0.8%, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0048] MgO: 1.2% to 1.5%, for example, 1.2%, 1.25%, 1.3%, 1.35%, 1.4% or 1.5%, etc., but is not limited to the values ​​listed above, and other values ​​not listed within the numerical range are also applicable;

[0049] SiO2: 3.5% to 4%, for example, 3.5%, 3.6%, 3.7%, 3.8%, 3.9% or 4%, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0050] Al2O3: 2% to 2.5%, for example, 2%, 2.1%, 2.2%, 2.3%, 2.4% or 2.5%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0051] TiO2: 8% to 8.3%, for example, 8%, 8.05%, 8.1%, 8.15%, 8.2%, 8.25% or 8.3%, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0052] V2O5: 0.5% to 0.7%, for example, 0.50%, 0.55%, 0.58%, 0.62%, 0.65% or 0.70%, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0053] P: 0.03% to 0.05%, for example, 0.03%, 0.035%, 0.04%, 0.045%, 0.048% or 0.05%, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0054] Cr2O3: 0.8% to 0.9%, for example, 0.80%, 0.82%, 0.84%, 0.86%, 0.88% or 0.90%, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0055] Preferably, the chromium-containing vanadium-titanium magnet sintered ore accounts for 55% to 60% of the total mass of the charge, for example, it can be 55%, 56.2%, 57%, 58.5%, 59.3% or 60%, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0056] Preferably, the chromium-containing vanadium-titanium magnetite pellets account for 40% to 45% of the total mass of the charge, for example, it can be 40%, 41.2%, 42.5%, 43.8%, 44.3% or 45%, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0057] The present invention preferably comprises 40% to 45% of the total mass of the chromium-containing vanadium-titanium magnetite pellets in the blast furnace charge, satisfying a reasonable charge structure for blast furnace smelting. A low proportion of the chromium-containing vanadium-titanium magnetite pellets reduces the total amount of vanadium entering the furnace and the vanadium content of the molten iron. A high proportion of the chromium-containing vanadium-titanium magnetite pellets reduces the permeability of the blast furnace, affecting the smooth operation of the blast furnace.

[0058] Preferably, the TFe of the charge is ≥ 56%, for example, it can be 56%, 57%, 58%, 59%, 60%, 63% or 65%, etc., but it is not limited to the listed values. Other values ​​not listed in the numerical range are also applicable.

[0059] Preferably, the vanadium load of the charge is 3.5-4.0 kg / t, for example, 3.5 kg / t, 3.6 kg / t, 3.7 kg / t, 3.8 kg / t, 3.9 kg / t or 4.0 kg / t, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0060] Preferably, the mass percentage of Si in the blast furnace molten iron is 0.20% to 0.60%, for example, it can be 0.20%, 0.30%, 0.40%, 0.45%, 0.55% or 0.60%, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0061] The mass percentage of Cr is ≤0.35%, for example, it can be 0.35%, 0.34%, 0.33%, 0.32%, 0.3%, 0.28% or 0.25%, etc., but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0062] Preferably, the mass percentage of MgO in the slag is 9.5% to 10.5%, for example, 9.5%, 9.7%, 9.9%, 10.1%, 10.3% or 10.5%, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0063] The mass percentage of TiO2 is ≤16%, for example, it can be 16%, 15%, 14%, 13%, 12%, 11% or 10%, etc., but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0064] Preferably, the MgO / Al2O3 in the slag produced by blast furnace smelting is 0.60-0.80, for example, it can be 0.60, 0.65, 0.68, 0.72, 0.76 or 0.80, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0065] Preferably, the binary basicity of the slag produced by blast furnace smelting is 1.15 to 1.25, for example, it can be 1.15, 1.17, 1.19, 1.21, 1.23 or 1.25, etc., but it is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0066] The present invention preferably has a MgO / Al2O3 ratio of 0.60 to 0.80 in the slag produced by blast furnace smelting, and a binary basicity of 1.15 to 1.25 in the slag produced by blast furnace smelting, which fully considers the effect of MgO on viscosity and melting temperature to ensure good slag fluidity.

[0067] As a preferred technical solution of the present invention, the method includes:

[0068] 55% to 60% of chromium-containing vanadium-titanium magnetite sintered ore and 40% to 45% of chromium-containing vanadium-titanium magnetite pellets are fed into a blast furnace for smelting, and the temperature of the blast furnace molten iron is controlled at 1400 to 1550° C. to obtain blast furnace molten iron with a high vanadium reduction rate;

[0069] The chromium-containing vanadium-titanium magnetite sintered ore is sintered by first chromium-containing vanadium-titanium magnetite powder and external ore powder; the external ore powder accounts for 8% to 15% of the total material mass; the first chromium-containing vanadium-titanium magnetite powder includes TFe: 62% to 63%, CaO: 2% to 2.5%, MgO: 1.5% to 1.8%, SiO2: 5% to 5.3%, Al2O3: 1.2% to 1.5%, TiO2: 1.5% to 2%, V2 O5: 0.2% to 0.6%, P: 0.01% to 0.02%, Cr2O3: 0.1% to 0.13%; the external mineral powder includes TFe: 63% to 65%, CaO: 1.3% to 1.5%, MgO: 2% to 2.3%, SiO2: 5% to 6%, Al2O3: 0.5% to 1%, TiO2: 0.2% to 0.25%, V2O5: 0.3% to 0.5%, P: 0.06% to 0.1%;

[0070] The chromium-containing vanadium-titanium magnetite sintered ore has TiO2 less than 2.2%, a binary basicity of 1.9 to 2.3, a drum strength of ≥80%, and RDI+3.15 ≥90%.

[0071] The chromium-containing vanadium-titanium magnetite pellets are obtained by granulating and molding a second chromium-containing vanadium-titanium magnetite powder; the second chromium-containing vanadium-titanium magnetite powder comprises, by mass percentage, TFe: 58% to 60%, CaO: 0.7% to 0.8%, MgO: 1.2% to 1.5%, SiO2: 3.5% to 4%, Al2O3: 2% to 2.5%, TiO2: 8% to 8.3%, V2O5: 0.5% to 0.7%, P: 0.03% to 0.05%, and Cr2O3: 0.8% to 0.9%;

[0072] The TFe of the charge is ≥56%, and the vanadium load is 3.5-4.0 kg / t;

[0073] The mass percentage of Si in the blast furnace molten iron is 0.20% to 0.60%, and the mass percentage of Cr is ≤0.35%; the mass percentage of MgO in the slag is 9.5% to 10.5%, and the mass percentage of TiO2 is ≤16%;

[0074] The MgO / Al2O3 ratio of the slag produced by blast furnace smelting is 0.60-0.80; the binary basicity of the slag produced by blast furnace smelting is 1.15-1.25.

[0075] Compared with the prior art, the present invention has at least the following beneficial effects:

[0076] The method for improving the vanadium reduction rate of molten iron by blast furnace smelting of chromium-containing vanadium-titanium magnetite provided by the present invention improves the vanadium reduction rate of molten iron by controlling the blast furnace molten iron temperature, blast furnace molten iron composition and blast furnace slag composition. The blast furnace condition is stable, the slag fluidity is good, the vanadium reduction rate of the blast furnace molten iron is improved to more than 89%, and the economic benefit is significant. BRIEF DESCRIPTION OF THE DRAWINGS

[0077] Figure 1 It is a flow chart of the method for improving the vanadium reduction rate of molten iron by blast furnace smelting of chromium-containing vanadium-titanium magnetite in Example 1 of the present invention. DETAILED DESCRIPTION

[0078] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific implementation methods.

[0079] The present invention is further described in detail below. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0080] Example 1

[0081] This embodiment provides a method for improving the vanadium reduction rate of molten iron in blast furnace smelting of chromium-containing vanadium-titanium magnetite. The flow diagram is as follows: Figure 1 As shown; the method includes:

[0082] 60% of chromium-containing vanadium-titanium magnetite sintered ore and 40% of chromium-containing vanadium-titanium magnetite pellets with a particle size of 10 mm are fed into a blast furnace for smelting, and the blast furnace molten iron temperature is controlled at 1500° C. to obtain blast furnace molten iron with a high vanadium reduction rate;

[0083] The chromium-containing vanadium-titanium magnetite sintered ore is sintered by mixing first chromium-containing vanadium-titanium magnetite powder and external ore powder; the external ore powder accounts for 10% of the total material mass; the first chromium-containing vanadium-titanium magnetite powder includes, by mass percentage, TFe: 62.5%, CaO: 2.19%, MgO: 1.72%, SiO2: 5.24%, Al2O3: 1.44%, TiO2: 1.75%, V2O5: 0.441%, P: 0.014%, and Cr2O3: 0.109%; the external ore powder includes TFe: 63.38%, CaO: 1.34%, MgO: 2.11%, SiO2: 5.7%, Al2O3: 0.94%, TiO2: 0.3%, V2O5: 0.386%, and P: 0.088%;

[0084] The chromium-containing vanadium-titanium magnetite sintered ore contains 2% TiO2, a binary basicity of 2, a drum strength of 82%, and an RDI+3.15 of 93%.

[0085] The chromium-containing vanadium-titanium magnetite pellets are obtained by granulating and molding a second chromium-containing vanadium-titanium magnetite powder; the second chromium-containing vanadium-titanium magnetite powder comprises, by mass percentage, TFe: 58.6%, CaO: 0.75%, MgO: 1.24%, SiO2: 3.72%, Al2O3: 2.22%, TiO2: 8.06%, V2O5: 0.657%, P: 0.035%, and Cr2O3: 0.81%;

[0086] The TFe content of the charge is 58%, and the vanadium load is 3.7 kg / t;

[0087] The mass percentage of Si in the blast furnace molten iron is 0.40%, and the mass percentage of Cr is 0.3%; the mass percentage of MgO in the slag is 10%, and the mass percentage of TiO2 is 13%;

[0088] The MgO / Al2O3 ratio of the slag produced by the blast furnace smelting is 0.70; the binary basicity of the slag produced by the blast furnace smelting is 1.2.

[0089] Example 2

[0090] This embodiment provides a method for increasing the vanadium reduction rate of molten iron in blast furnace smelting of chromium-containing vanadium-titanium magnetite, the method comprising:

[0091] 55% of chromium-containing vanadium-titanium magnetite sintered ore and 45% of chromium-containing vanadium-titanium magnetite pellets with a particle size of 16 mm are fed into a blast furnace for smelting, and the blast furnace molten iron temperature is controlled at 1400° C. to obtain blast furnace molten iron with a high vanadium reduction rate;

[0092] The chromium-containing vanadium-titanium magnetite sintered ore is sintered by a first chromium-containing vanadium-titanium magnetite powder and an external ore powder; the external ore powder accounts for 8% of the total material mass; the first chromium-containing vanadium-titanium magnetite powder includes, by mass percentage, TFe: 63%, CaO: 2.5%, MgO: 1.5%, SiO2: 5%, Al2O3: 1.2%, TiO2: 1.5%, V2O5: 0.2%, P: 0.01%, and Cr2O3: 0.13%; the external ore powder includes TFe: 65%, CaO: 1.5%, MgO: 2.3%, SiO2: 6%, Al2O3: 0.5%, TiO2: 0.2%, V2O5: 0.3%, and P: 0.06%;

[0093] The chromium-containing vanadium-titanium magnetite sintered ore has a TiO2 content of 2.1%, a binary basicity of 1.9, a drum strength of 88%, and an RDI+3.15 of 95%.

[0094] The chromium-containing vanadium-titanium magnetite pellets are obtained by granulating and molding a second chromium-containing vanadium-titanium magnetite powder; the second chromium-containing vanadium-titanium magnetite powder comprises, by mass percentage, TFe: 58%, CaO: 0.8%, MgO: 1.2%, SiO2: 3.5%, Al2O3: 2.5%, TiO2: 8.3%, V2O5: 0.7%, P: 0.03%, and Cr2O3: 0.9%;

[0095] The TFe content of the charge is 58%, and the vanadium load is 3.5 kg / t;

[0096] The mass percentage of Si in the blast furnace molten iron is 0.20%, and the mass percentage of Cr is 0.31%; the mass percentage of MgO in the slag produced by the blast furnace smelting is 9.5%, and the mass percentage of TiO2 is 13%;

[0097] The MgO / Al2O3 ratio of the slag produced by the blast furnace smelting is 0.60; the binary basicity of the slag produced by the blast furnace smelting is 1.15.

[0098] Example 3

[0099] This embodiment provides a method for increasing the vanadium reduction rate of molten iron in blast furnace smelting of chromium-containing vanadium-titanium magnetite, the method comprising:

[0100] 60% of chromium-containing vanadium-titanium magnetite sintered ore and 40% of chromium-containing vanadium-titanium magnetite pellets with a particle size of 8 mm are fed into a blast furnace for smelting, and the blast furnace molten iron temperature is controlled at 1550° C. to obtain blast furnace molten iron with a high vanadium reduction rate;

[0101] The chromium-containing vanadium-titanium magnetite sintered ore is sintered by a first chromium-containing vanadium-titanium magnetite powder and an external ore powder; the external ore powder accounts for 15% of the total material mass; the first chromium-containing vanadium-titanium magnetite powder includes, by mass percentage, TFe: 62%, CaO: 2%, MgO: 1.8%, SiO2: 5.3%, Al2O3: 1.5%, TiO2: 2%, V2O5: 0.6%, P: 0.02%, and Cr2O3: 0.1%; the external ore powder includes TFe: 63%, CaO: 1.3%, MgO: 2%, SiO2: 5%, Al2O3: 1%, TiO2: 0.25%, V2O5: 0.5%, and P: 0.1%;

[0102] The chromium-containing vanadium-titanium magnetite sintered ore has a TiO2 content of 1.8%, a binary basicity of 2.3, a drum strength of 87%, and an RDI+3.15 of 92.5%.

[0103] The chromium-containing vanadium-titanium magnetite pellets are obtained by granulating and molding a second chromium-containing vanadium-titanium magnetite powder; the second chromium-containing vanadium-titanium magnetite powder comprises, by mass percentage, TFe: 60%, CaO: 0.7%, MgO: 1.5%, SiO2: 4%, Al2O3: 2%, TiO2: 8%, V2O5: 0.5%, P: 0.05%, and Cr2O3: 0.8%;

[0104] The TFe of the charge is ≥56%, and the vanadium load is 4.0 kg / t;

[0105] The mass percentage of Si in the blast furnace molten iron is 0.60%, and the mass percentage of Cr is 0.25%; the mass percentage of MgO in the slag produced by the blast furnace smelting is 10.5%, and the mass percentage of TiO2 is 12%;

[0106] The MgO / Al2O3 ratio of the slag produced by the blast furnace smelting is 0.80; the binary basicity of the slag produced by the blast furnace smelting is 1.25.

[0107] Based on Examples 1 to 3, the method for improving the vanadium reduction rate of molten iron in blast furnace smelting of chromium-containing vanadium-titanium magnetite provided by the present invention can ensure stable blast furnace conditions, good slag fluidity, and a vanadium reduction rate of blast furnace molten iron of more than 89%.

[0108] Example 4

[0109] This embodiment provides a method for improving the vanadium reduction rate of molten iron in blast furnace smelting of chromium-containing vanadium-titanium magnetite. The method is the same as that of Example 1 except that the TiO2 content in the chromium-containing vanadium-titanium magnetite sintered ore is 2.5%.

[0110] In this embodiment, due to the high TiO2 content in the chromium-containing vanadium-titanium magnet sintered ore, the quality of the vanadium-titanium sintered ore deteriorates and the vanadium content of the sintered ore decreases.

[0111] Example 5

[0112] This embodiment provides a method for improving the vanadium reduction rate of molten iron in blast furnace smelting of chromium-containing vanadium-titanium magnetite. The method is the same as that of Example 1 except that the binary basicity of the chromium-containing vanadium-titanium magnetite sintered ore is 1.5.

[0113] Example 6

[0114] This embodiment provides a method for improving the vanadium reduction rate of molten iron in blast furnace smelting of chromium-containing vanadium-titanium magnetite. The method is the same as that of Example 1 except that the binary basicity of the chromium-containing vanadium-titanium magnetite sintered ore is 2.5.

[0115] From the combination of Example 1 and Examples 5 to 6, it can be seen that the binary basicity in Example 5 is relatively low, the sintering liquid phase is insufficient, and the sintering physical and chemical properties are reduced; the binary basicity in Example 6 is relatively high, which makes the slag sticky, deteriorates the fluidity, and may cause accumulation in the furnace; and the melting point of the slag is increased, which increases fuel consumption.

[0116] Example 7

[0117] This embodiment provides a method for improving the vanadium reduction rate of molten iron in blast furnace smelting of chromium-containing vanadium-titanium magnetite. The method is the same as that of Example 1 except that the chromium-containing vanadium-titanium magnetite pellets account for 35% of the total mass of the charge.

[0118] Example 8

[0119] This embodiment provides a method for improving the vanadium reduction rate of molten iron in blast furnace smelting of chromium-containing vanadium-titanium magnetite. The method is the same as that of Example 1 except that the chromium-containing vanadium-titanium magnetite pellets account for 50% of the total mass of the charge.

[0120] From Example 1 and Examples 7 to 8, it can be seen that the proportion of chromium-containing vanadium-titanium magnetite pellets in Example 7 is low, which will lead to a decrease in the total amount of vanadium entering the furnace and a decrease in vanadium in molten iron; the proportion of chromium-containing vanadium-titanium magnetite pellets in Example 8 is high, which will lead to poor permeability of the blast furnace and affect the smooth operation of the blast furnace.

[0121] Comparative Example 1

[0122] This comparative example provides a method for smelting chromium-containing vanadium-titanium magnetite in a blast furnace. The method is the same as Example 1 except that the temperature of the blast furnace molten iron is 1300°C.

[0123] Comparative Example 2

[0124] This comparative example provides a method for smelting chromium-containing vanadium-titanium magnetite in a blast furnace. The method is the same as Example 1 except that the temperature of the blast furnace molten iron is 1600°C.

[0125] From Example 1 and Comparative Examples 1 to 2, it can be seen that in Comparative Example 1, the temperature of the blast furnace molten iron is relatively low, the slag and iron are viscous, and the separation of iron and slag is difficult; in Comparative Example 2, since the temperature of the blast furnace molten iron is relatively high, carbon deposition will occur in the subsequent cooling process, causing the molten iron to become viscous rapidly and the fluidity to deteriorate, which also makes the separation of slag and iron difficult.

[0126] In summary, the method for improving the vanadium reduction rate of molten iron in blast furnace smelting of chromium-containing vanadium-titanium magnetite provided by the present invention controls the quality of sintered ore, the composition and structure of the charge, the temperature of the molten iron in the blast furnace, the composition of the molten iron in the blast furnace and the composition of the slag, thereby significantly improving the vanadium reduction rate of the molten iron in the blast furnace while ensuring the stability of the blast furnace condition and good slag fluidity, and has prospects for large-scale promotion and application.

[0127] The applicant declares that the above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A method for increasing the vanadium reduction rate of molten iron in blast furnace smelting of chromium-containing vanadium-titanium magnetite, characterized in that: The method comprises: Chromium-containing vanadium-titanium magnetite sintered ore and chromium-containing vanadium-titanium magnetite pellets are fed into a blast furnace for smelting, and the temperature of the blast furnace molten iron is controlled at 1400-1550° C. to obtain blast furnace molten iron with a high vanadium reduction rate.

2. The method according to claim 1, characterized in that The chromium-containing vanadium-titanium magnetite sintered ore is sintered by first chromium-containing vanadium-titanium magnetite powder and external ore powder; Preferably, the external mineral powder accounts for 8% to 15% of the total material mass; Preferably, the first chromium-containing vanadium-titanium magnetite powder comprises, by mass percentage, TFe: 62% to 63%, CaO: 2% to 2.5%, MgO: 1.5% to 1.8%, SiO2: 5% to 5.3%, Al2O3: 1.2% to 1.5%, TiO2: 1.5% to 2%, V2O5: 0.2% to 0.6%, P: 0.01% to 0.02%, and Cr2O3: 0.1% to 0.13%; Preferably, the external mineral powder includes TFe: 63% to 65%, CaO: 1.3% to 1.5%, MgO: 2% to 2.3%, SiO2: 5% to 6%, Al2O3: 0.5% to 1%, TiO2: 0.2% to 0.25%, V2O5: 0.3% to 0.5%, and P: 0.06% to 0.1%.

3. The method according to claim 1 or 2, characterized in that The TiO2 content of the chromium-containing vanadium-titanium magnetite sintered ore is less than 2.2%; Preferably, the binary basicity of the chromium-containing vanadium-titanium magnetite sintered ore is 1.9 to 2.3; Preferably, the drum strength of the chromium-containing vanadium-titanium magnetite sintered ore is ≥80%; Preferably, the RDI+3.15 of the chromium-containing vanadium-titanium magnetite sintered ore is ≥90%.

4. The method according to any one of claims 1 to 3, characterized in that The chromium-containing vanadium-titanium magnetite pellets are obtained by granulating and molding the second chromium-containing vanadium-titanium magnetite powder; Preferably, the second chromium-containing vanadium-titanium magnetite powder includes, by mass percentage, TFe: 58% to 60%, CaO: 0.7% to 0.8%, MgO: 1.2% to 1.5%, SiO2: 3.5% to 4%, Al2O3: 2% to 2.5%, TiO2: 8% to 8.3%, V2O5: 0.5% to 0.7%, P: 0.03% to 0.05%, and Cr2O3: 0.8% to 0.9%.

5. The method according to any one of claims 1 to 4, characterized in that The chromium-containing vanadium-titanium magnetite sintered ore accounts for 55% to 60% of the total mass of the charge; Preferably, the chromium-containing vanadium-titanium magnetite pellets account for 40% to 45% of the total mass of the charge.

6. The method according to any one of claims 1 to 5, characterized in that The TFe of the charge is ≥56%.

7. The method according to any one of claims 1 to 6, characterized in that The vanadium load of the charge is 3.5-4.0 kg / t.

8. The method according to any one of claims 1 to 7, characterized in that The mass percentage of Si in the blast furnace molten iron is 0.20% to 0.60%, and the mass percentage of Cr is ≤0.35%.

9. The method according to any one of claims 1 to 8, characterized in that The mass percentage of MgO in the slag produced by blast furnace smelting is 9.5% to 10.5%, and the mass percentage of TiO2 is ≤16%; Preferably, the MgO / Al2O3 ratio in the slag produced by blast furnace smelting is 0.60 to 0.80; Preferably, the binary basicity of the slag produced by blast furnace smelting is 1.15 to 1.

25.

10. The method according to any one of claims 1 to 9, characterized in that The method comprises: 55% to 60% of chromium-containing vanadium-titanium magnetite sintered ore and 40% to 45% of chromium-containing vanadium-titanium magnetite pellets are fed into a blast furnace for smelting, and the temperature of the blast furnace molten iron is controlled at 1400 to 1550° C. to obtain blast furnace molten iron with a high vanadium reduction rate; The chromium-containing vanadium-titanium magnetite sintered ore is sintered by first chromium-containing vanadium-titanium magnetite powder and external ore powder; the external ore powder accounts for 8% to 15% of the total material mass; the first chromium-containing vanadium-titanium magnetite powder includes TFe: 62% to 63%, CaO: 2% to 2.5%, MgO: 1.5% to 1.8%, SiO2: 5% to 5.3%, Al2O3: 1.2% to 1.5%, TiO2: 1.5% to 2%, V2 O5: 0.2% to 0.6%, P: 0.01% to 0.02%, Cr2O3: 0.1% to 0.13%; the external mineral powder includes TFe: 63% to 65%, CaO: 1.3% to 1.5%, MgO: 2% to 2.3%, SiO2: 5% to 6%, Al2O3: 0.5% to 1%, TiO2: 0.2% to 0.25%, V2O5: 0.3% to 0.5%, P: 0.06% to 0.1%; The chromium-containing vanadium-titanium magnetite sintered ore has TiO2 less than 2.2%, a binary basicity of 1.9 to 2.3, a drum strength of ≥80%, and RDI+3.15 ≥90%. The chromium-containing vanadium-titanium magnetite pellets are obtained by granulating and molding a second chromium-containing vanadium-titanium magnetite powder; the second chromium-containing vanadium-titanium magnetite powder comprises, by mass percentage, TFe: 58% to 60%, CaO: 0.7% to 0.8%, MgO: 1.2% to 1.5%, SiO2: 3.5% to 4%, Al2O3: 2% to 2.5%, TiO2: 8% to 8.3%, V2O5: 0.5% to 0.7%, P: 0.03% to 0.05%, and Cr2O3: 0.8% to 0.9%; The TFe of the charge is ≥56%, and the vanadium load is 3.5-4.0 kg / t; The mass percentage of Si in the blast furnace molten iron is 0.20% to 0.60%, and the mass percentage of Cr is ≤0.35%; the mass percentage of MgO in the slag is 9.5% to 10.5%, and the mass percentage of TiO2 is ≤16%; The MgO / Al2O3 ratio in the slag produced by the blast furnace smelting is 0.60-0.80; the binary basicity of the slag produced by the blast furnace smelting is 1.15-1.25.

Images