CN115896367A - A kind of blast furnace smelting method of vanadium-titanium magnetite - Google Patents

Abstract

The invention discloses a blast furnace smelting method of vanadium-titanium magnetite, relates to the technical field of blast furnace smelting, solves the problem of serious iron loss in the existing blast furnace smelting vanadium-titanium magnetite method, and comprises the following steps: S1, providing smelting composition of raw materials; S2, according to the composition of the raw materials described in S1, take the materials and put them into the blast furnace for distribution to obtain the furnace charge structure; S3, adjust the thermal system of smelting to smelt and tap the iron according to the preset time to obtain finished products. Make adjustments, introduce elements that increase the fluidity of the slag, improve the ability of the slag to discharge Ti C and TiN, reduce the accumulation of Ti C and TiN in the slag, and reduce the adsorption of dispersed Ti (C, N) and iron, making the slag iron It can be separated smoothly, thereby effectively reducing the loss of iron in the finished product, and adjusting the heat system of smelting to provide a more suitable environment for the fluidity of the slag, thereby further reducing the loss of iron in the finished product.

Description

A kind of blast furnace smelting method of vanadium-titanium magnetite

technical field

The invention relates to the technical field of blast furnace smelting, in particular to a blast furnace smelting method of vanadium-titanium magnetite.

Background technique

Vanadium-titanium magnetite is a symbiotic compound ore composed of iron, vanadium, titanium and other valuable elements. It is also an important resource of vanadium and titanium, and a mineral resource widely distributed in the world. Vanadium-titanium magnetite is also one of the world-recognized refractory minerals. Its comprehensive utilization is difficult, but its smelting cost is lower than that of ordinary ore smelting, and its comprehensive utilization rate is higher.

The smelting melting point of vanadium-titanium magnetite is 50-100°C higher than that of ordinary ore. If the melting point temperature is not reached, it will lose fluidity; in addition, because TiO2 in the slag is reduced to TiC and TiN, it exists in the solid phase in the slag and disperses. In the future, the slag will thicken and lose its fluidity. In addition, the smelting grade of vanadium-titanium ore is low and the amount of slag is large, so the loss of iron is large. The iron loss in the ordinary ore smelting process is 0.5-2%, and the TFe content in the slag is 0.5-1%, while the TFe content in the vanadium-titanium magnetite smelting slag is 2.5-4.5%.

It can be seen that the existing blast furnace method for smelting vanadium-titanium magnetite has the problem of serious iron loss. The present invention aims at the above problem and designs a blast furnace method for smelting vanadium-titanium magnetite.

Contents of the invention

The purpose of the present invention is: in order to solve the problem of serious iron loss in the existing blast furnace smelting method of vanadium-titanium magnetite, the present invention provides a blast furnace smelting method of vanadium-titanium magnetite, by adjusting the raw material composition, introducing increased The elements of slag fluidity can improve the ability of slag to discharge Ti C and TiN, reduce the accumulation of Ti C and TiN in slag, and reduce the adsorption of dispersed Ti (C, N) and iron, so that slag and iron can be separated smoothly, thus effectively The loss of iron in the finished product is reduced, and the loss of iron is controlled from the source; further, a more suitable environment is provided for the fluidity of the slag by adjusting the thermal system of smelting, thereby further reducing the loss of iron in the finished product; it is realized to provide a vanadium-titanium The blast furnace smelting method of magnetite.

The present invention specifically adopts the following technical solutions in order to achieve the above object:

A blast furnace smelting method for vanadium-titanium magnetite, comprising the following steps: S1, providing raw material composition for smelting; S2, taking material according to the raw material composition of S1 and putting it into the blast furnace for distribution to obtain the charge structure; S3, adjusting the smelting The heat system is used to smelt and tap the iron according to the preset time to obtain the finished product.

Optionally, the smelting raw material composition includes 50-58% of manganese-containing sintered ore, 38-45% of pellet ore, and 5-15% of raw ore.

Optionally, each part of the manganese-containing sintered ore contains 0.55-0.75% MnO.

Optionally, adjusting the heat regime of smelting in S3 includes controlling the content of [Ti]+[Si] in the molten iron to 0.25%-0.4%.

Optionally, adjusting the heat regime of smelting in S3 includes setting the furnace temperature to 1430-1500°C. Compared with the prior art, the present invention has the advantages of:

1. the blast furnace smelting method of a kind of vanadium-titanium magnetite involved in the present invention, by adjusting raw material composition, introduce the element that increases slag fluidity, improve the ability of slag discharge Ti C and TiN, reduce Ti C and TiN in The accumulation in the slag reduces the adsorption of dispersed Ti (C, N) and iron, so that the slag and iron can be separated smoothly, thereby effectively reducing the loss of iron in the finished product and controlling the loss of iron from the source; further, by adjusting the heat of smelting The system provides a more suitable environment for the fluidity of the slag, thereby further reducing the loss of iron in the finished product; it can be seen that the present invention controls the loss of iron through multiple dimensions, and solves the problem of iron loss in the existing blast furnace smelting vanadium-titanium magnetite method. serious loss problem.

2. The blast furnace smelting method of a kind of vanadium-titanium magnetite involved in the present invention, the raw material composition of adjustment smelting can change the composition of slag, makes the content of MnO in the slag at 1.0-1.5%, the content of MnO in the slag increases, can Change the fluidity of the slag, increase the fluidity of the slag, _TiO2 in the slag is reduced to TiC and TiN and exist in the solid phase, which increases the fluidity of the slag, improves the ability of the slag to discharge TiC and TiN, and reduces the dispersion of Ti ( The adsorption of C, N) and iron enables the smooth separation of slag and iron, thereby reducing the loss of iron in the finished product.

3. A kind of blast furnace smelting method of vanadium-titanium magnetite involved in the present invention, the raw material composition of smelting described in the present invention comprises by mass parts, 52-58 parts of manganese-containing sintered ore, 5-10 parts of pellet ore , 10-12 parts of raw ore. The ratio of sintered ore and pelletized ore into the furnace is called clinker ratio. It can be seen that in the present invention, the clinker ratio is greater than 94%, and increasing the clinker ratio is beneficial to improve the loss of iron. The main reason is that the reducibility of clinker is better than that of raw meal. The direct reduction of ore is an endothermic reaction, while the indirect reduction is an exothermic reaction. The released heat participates in the blast furnace smelting process, which reduces heat loss and ensures sufficient The furnace temperature can avoid the increase of the viscosity of the slag and improve the fluidity of the slag. At the same time, the coke ratio can be reduced by 6-7kg/t after the clinker ratio is increased, which also reduces the production cost, which has advantages.

Description of drawings

Fig. 1 is a schematic flow chart of a blast furnace smelting method for vanadium-titanium magnetite.

Figure 2 is a schematic diagram of the equilibrium gas phase composition of CO reduction of iron oxides at different temperatures.

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them. the embodiment.

Accordingly, the following detailed description of the embodiments of the invention provided is not intended to limit the scope of the claimed invention, but represents only selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

Detailed ways

(1) The main reason for the high iron loss in vanadium-titanium magnetite smelting

① The reduction of titanium oxide is stepwise reduction, and the reduction sequence is:

Ti0 ₂ —Ti ₃ O ₅ —Ti ₂ O ₃ —TiO—Ti

Titanium suboxides can only react directly with C:

Ti ₂ O ₃ +C＝2Ti0+CO

TiO+C=Ti+CO

This reaction can only be carried out at high temperature. However, Ti has high activity at high temperature, and it will react with C and N2:

Ti0 ₂ +3C＝TiC+2C0

Ti+C=TiC

Ti0 ₂ +2C+1/2N ₂ =TiN+2C0

Ti+1/2N ₂ =TiN

The Ti(C, N) compound generated by the reduced Ti has a very high melting point (2900-3000°C), they are high-density dispersed solid phases, and have good wettability with the slag, making the slag viscosity At the same time, the dispersed Ti(C, N) generated by over-reduction is adsorbed on the small iron beads, which increases the surface tension of the iron beads, making it difficult for the small iron beads to aggregate and grow, resulting in a large number of dispersed small iron beads in the slag, resulting in Iron separation is difficult, resulting in iron loss during smelting.

②Because the vanadium-titanium ore contains high TiO2, the furnace grade is lower than that of ordinary ore smelting, which makes the amount of iron slag per ton higher, and the greater the amount of slag, the higher the iron loss.

③The effect of temperature on iron loss: the influence of furnace temperature on the viscosity of slag causes iron loss: the viscosity of slag decreases with the increase of temperature, and the relationship between the viscosity and temperature of most slag follows the Arrhenius relationship:

In formula (1), A _η is a constant; E _η is the activation energy of viscous flow.

Therefore, during the smelting process of vanadium-titanium ore, when the furnace temperature is too high, the viscosity of the slag decreases, the fluidity becomes poor, and the separation effect of slag and iron becomes poor, which increases the amount of iron taken away by the slag, resulting in iron loss in the smelting process;

When the furnace temperature is low, Fe _x O in the ore cannot be fully oxidized and reduced. Fe _x O is a cubic sodium chloride-type Fe ²⁺ -deficient crystal, and its scientific name is wurstite (floating body). Usually recorded as FeO. According to the equilibrium gas phase composition diagram of CO reduction of iron oxides at different temperatures (see Figure 2), it can be seen that when CO is used as a reducing agent, when the temperature decreases, to ensure that FeO is reduced to Fe, the volume fraction of CO in the gas phase must increase as the temperature decreases. High, and the generation of CO is an exothermic reaction, which is positively correlated with temperature. Therefore, when the temperature drops, the volume fraction of CO in the gas phase will inevitably decrease, which cannot guarantee that FeO will be reduced to Fe, and the part of FeO that has not been completely reduced will be Into the slag, causing iron loss.

Therefore please refer to shown in Fig. 1, a kind of blast furnace smelting method of vanadium-titanium magnetite provided by the present invention comprises the following steps: S1, the raw material composition of smelting is provided; S2, take material according to the described raw material composition of S1 and drop into blast furnace Carry out material distribution to obtain the charge structure; S3, adjust the heat system of smelting to smelt and tap iron according to the preset time to obtain the finished product.

It is understandable that by adjusting the raw material composition, introducing elements that increase the fluidity of the slag, improving the ability of the slag to discharge Ti C and TiN, reducing the accumulation of Ti C and TiN in the slag, and reducing the dispersion of Ti(C,N) The adsorption with iron enables the smooth separation of slag and iron, thereby effectively reducing the loss of iron in the finished product and controlling the loss of iron from the source; further, by adjusting the thermal system of smelting to provide a more suitable environment for the fluidity of slag, thereby further The loss of iron in the finished product is reduced; it can be seen that the present invention controls the loss of iron through multiple dimensions, and solves the problem of serious iron loss in the existing method for smelting vanadium-titanium magnetite in a blast furnace.

In some embodiments of the present invention, the composition of raw materials for smelting includes 50-58% of manganese-containing sintered ore, 38-45% of pellet ore, and 5-15% of raw ore.

Specifically, the smelting raw material composition includes 50% manganese-containing sintered ore, 38% pellet ore, and 5% raw ore.

Specifically, the smelting raw material composition includes 55% manganese-containing sintered ore, 40% pellet ore, and 10% raw ore.

Specifically, the smelting raw material composition includes 58% manganese-containing sintered ore, 45% pellet ore, and 15% raw ore.

In some embodiments of the present invention, each part of the manganese-containing sinter contains 0.55-0.75% MnO.

Specifically, each part of the manganese-containing sinter contains 0.65% MnO.

It can be understood that adjusting the composition of smelting raw materials can change the composition of the slag, so that the content of MnO in the slag is 1.0-1.5%, and the content of MnO in the slag increases, which can change the fluidity of the slag and increase the fluidity of the slag. TiO in the slag ₂ It is reduced to TiC and TiN in solid phase, which increases the fluidity of the slag, improves the ability of the slag to discharge TiC and TiN, reduces the adsorption of dispersed Ti (C, N) and iron, and enables the smooth separation of slag and iron. Thereby reducing the loss of iron in the finished product.

Further specific elaboration, because the reduction process of manganese oxide is an exothermic reaction, and the thermal effect value is relatively large, which can increase the furnace temperature during the smelting process and reduce the probability of the furnace temperature being too low during the production process. At the same time, increase the content of slag MnO in the smelting process. Slag MnO can increase the oxygen form of slag, inhibit the over-reduction of _TiO2 , generate manganese olivine with a lower melting point, reduce the melting temperature of slag, and keep the slag in a wide range. Homogeneous liquid. As a result, the reduction ratio of FeO is increased, the fluidity of slag is improved, and the iron loss in the smelting process is reduced.

In addition, the composition of raw materials for smelting in the present invention includes 52-58 parts of manganese-containing sintered ore, 5-10 parts of pellet ore, and 10-12 parts of raw ore in parts by mass. The ratio of sintered ore and pelletized ore into the furnace is called clinker ratio. It can be seen that in the present invention, the clinker ratio is greater than 94%, and increasing the clinker ratio is beneficial to improve the loss of iron.

Understandably, the main reason is that the reduction of clinker is better than that of raw meal. The direct reduction of ore is an endothermic reaction, while the indirect reduction is an exothermic reaction. The released heat participates in the blast furnace smelting process, reducing heat loss , ensuring sufficient furnace temperature, avoiding the increase of slag viscosity, improving the fluidity of slag, and increasing the clinker ratio can reduce the coke ratio by 6-7kg/t, which also reduces the production cost, which has advantages.

In some embodiments of the present invention, the manganese-containing sintered ore includes: TFe 47-49.5%, FeO 7-10%, SiO ₂ 5-7%, TiO ₂ 4-7%, V ₂ O ₅ 0.2-1%, MnO 0.55-0.75%.

In some embodiments of the present invention, the pellets include: TFe 52-55%, FeO 1-2%, SiO ₂ 4-6%, TiO ₂ 10-12%, V ₂ O ₅ 0.4-1%, moisture 0.01-3.6%.

In some embodiments of the present invention, the raw ore includes: 50-56% TFe, 12-16% SiO ₂ , 0.4-0.8% TiO ₂ , and 2-3% moisture in parts by mass.

In some embodiments of the present invention, adjusting the thermal regime of smelting in S3 includes controlling the content of [Ti]+[Si] in molten iron to 0.25%-0.4%.

Specifically, in some embodiments of the present invention, adjusting the thermal regime of smelting in S3 includes controlling the content of [Ti]+[Si] in molten iron to 0.3%.

It can be understood that the Ti (C, N) compound produced by the reduction reaction of Ti with C and N has a very high melting point (2900-3000 °C), and they are high-density dispersed solid phases, which have a close relationship with slag. Good wettability increases the viscosity of the slag, and at the same time, the dispersed Ti(C, N) generated by over-reduction is adsorbed on the small iron beads, which increases the surface tension of the iron beads and makes it difficult for the small iron beads to aggregate and grow, resulting in There are a large number of dispersed small iron beads, which makes the separation of slag and iron difficult, resulting in iron loss during the smelting process. It can be seen that by reducing the content of [Ti]+[Si] in molten iron, the probability of Ti forming solid phase substances with carbon and nitrogen can be reduced, thereby reducing iron loss from the source.

Furthermore, reducing the Si content in molten iron will increase the grade of the furnace compared with ordinary ore smelting, thereby reducing the amount of iron slag per ton, and the greater the amount of slag, the lower the iron loss.

In some embodiments of the present invention, adjusting the heat regime of smelting in S3 includes setting the furnace temperature to 1430-1500°C.

Specifically, in some embodiments of the present invention, adjusting the thermal regime of smelting in S3 includes setting the furnace temperature to 1450°C.

Understandably, the viscosity-temperature dependence of most slags follows the Arrhenius relationship:

In formula (1), A _η is a constant; E _η is the activation energy of viscous flow.

Therefore, during the smelting process of vanadium-titanium ore, when the furnace temperature is too high, the viscosity of the slag will decrease, the fluidity will deteriorate, and the separation effect of slag and iron will deteriorate, which will increase the amount of iron taken away by the slag and cause iron loss in the smelting process;

When the furnace temperature is low, Fe _x O in the ore cannot be fully oxidized and reduced. Fe _x O is a cubic sodium chloride-type Fe ²⁺ -deficient crystal, and its scientific name is wurstite (floating body). Usually recorded as FeO. According to the equilibrium gas phase composition diagram of CO reduction of iron oxides at different temperatures (see Figure 1), it can be seen that when CO is used as a reducing agent, when the temperature decreases, to ensure that FeO is reduced to Fe, the volume fraction of CO in the gas phase must increase as the temperature decreases. High, and the generation of CO is an exothermic reaction, which is positively correlated with temperature. Therefore, when the temperature drops, the volume fraction of CO in the gas phase will inevitably decrease, which cannot guarantee that FeO will be reduced to Fe, and the part of FeO that has not been completely reduced will be Into the slag, causing iron loss.

Therefore, the furnace temperature is set at 1430-1500°C, which effectively reduces the loss of iron.

In some embodiments of the present invention, the preset time is adjusted according to the blast furnace equipment used, so as to minimize the residence time of slag and iron in the furnace, weaken the condition for slag to become viscous, and reduce iron loss.

In addition, in some embodiments of the present invention, during the production process, production management is strengthened, and specific measures include:

①Raw material and fuel control

The blast furnace foreman is required to check the quality of raw materials and fuels and the charging system before each shift takes over, pay attention to moisture changes, powder content, and immediately report and deal with any abnormalities, so as to stabilize the production efficiency and quality of each shift, and create benefits for blast furnace intensified smelting conditions, so as to avoid the problem of increased iron loss caused by too high or too low furnace temperature.

② Production rhythm control

When the smelting intensity of the blast furnace is increased, the flow rate of the incoming charge and the slag iron from the furnace is accelerated. Our factory requires the blast furnace workshop to strictly control the iron interval time of each furnace. The interval between iron and iron is less than 15 minutes, which reduces the residence time of slag and iron in the furnace, weakens the condition for slag to become viscous, and reduces iron loss.

Example 1

When smelting vanadium-titanium iron ore, carry out blast furnace smelting according to the method for reducing the iron loss of blast furnace smelting vanadium-titanium magnetite as follows, specifically: include the following steps:

S1. Provide the raw material composition for smelting; the raw material composition for smelting includes 50% manganese-containing sintered ore, 38% pellet ore, and 5% raw ore. Each part of the manganese-containing sinter contains 0.55% MnO

S2. Taking materials according to the composition of raw materials in S1 and putting them into the blast furnace for distribution to obtain the furnace material structure; controlling the content of [Ti]+[Si] in molten iron to 0.3%; setting the furnace temperature to 1450°C;

S3. Adjust the heat regime of smelting to smelt and tap iron according to the preset time to obtain finished products.

Example 2

When smelting vanadium-titanium iron ore, carry out blast furnace smelting according to the method for reducing the iron loss of blast furnace smelting vanadium-titanium magnetite as follows, specifically: include the following steps:

S1. Provide the raw material composition for smelting; the raw material composition for smelting includes 55% manganese-containing sintered ore, 40% pellet ore, and 10% raw ore. Each part of the manganese-containing sinter contains 0.60% MnO.

S2. Taking materials according to the composition of raw materials in S1 and putting them into the blast furnace for distribution to obtain the furnace material structure; controlling the content of [Ti]+[Si] in molten iron to 0.3%; setting the furnace temperature to 1430°C;

S3. Adjust the heat regime of smelting to smelt and tap iron according to the preset time to obtain finished products.

Example 3

When smelting vanadium-titanium iron ore, carry out blast furnace smelting according to the method for reducing the iron loss of blast furnace smelting vanadium-titanium magnetite as follows, specifically: include the following steps:

S1. Provide the raw material composition for smelting; the raw material composition for smelting includes 58% of manganese-containing sintered ore, 45% of pellet ore, and 15% of raw ore. Each part of the manganese-containing sinter contains 0.75% MnO.

S2. Taking materials according to the raw material composition of S1 and putting them into the blast furnace for distribution to obtain the furnace material structure; controlling the [Ti]+[Si] content in the molten iron to 0.3%; setting the furnace temperature to 1500°C;

S3. Adjust the heat regime of smelting to smelt and tap iron according to the preset time to obtain finished products.

Example 4

When smelting vanadium-titanium iron ore, carry out blast furnace smelting according to the method for reducing the iron loss of blast furnace smelting vanadium-titanium magnetite as follows, specifically: include the following steps:

S1. Provide the raw material composition for smelting; the raw material composition for smelting includes 50% of manganese-containing sintered ore, 38% of pellet ore, and 5% of raw ore. Each part of the manganese-containing sinter contains 0.55% MnO.

S2. Taking materials according to the composition of raw materials in S1 and putting them into the blast furnace for distribution to obtain the furnace material structure; controlling the content of [Ti]+[Si] in molten iron to 0.3%; setting the furnace temperature to 1480°C;

S3. Adjust the heat regime of smelting to smelt and tap iron according to the preset time to obtain finished products.

Example 5

When smelting vanadium-titanium iron ore, carry out blast furnace smelting according to the method for reducing the iron loss of blast furnace smelting vanadium-titanium magnetite as follows, specifically: include the following steps:

S1. Provide the raw material composition for smelting; the raw material composition for smelting includes 55% of manganese-containing sintered ore, 40% of pellet ore, and 10% of raw ore. Each part of the manganese-containing sinter contains 0.55% MnO

S2. Taking materials according to the raw material composition of S1 and putting them into the blast furnace for distribution to obtain a furnace material structure; controlling the content of [Ti]+[Si] in molten iron to 0.3%; setting the furnace temperature to 1490°C;

S3. Adjust the heat regime of smelting to smelt and tap iron according to the preset time to obtain finished products.

After improving the viscosity of the slag, increasing the fluidity of the slag, and increasing the reduction ratio of FeO by the above method, the TFe content in the slag of Examples 1-5 decreased from 1.5% to about 0.75%, and the annual iron loss of this enterprise with a scale of 2.65 million tons of iron was reduced by 1.232% The economic benefit of 10,000 tons (slag ratio 0.62t/t.Fe) is 43.12 million yuan/year (the cost of pig iron is calculated at 3,500 yuan/ton).

In summary, a blast furnace smelting method of vanadium-titanium magnetite involved in the present invention, by adjusting the composition of raw materials, introducing elements that increase the fluidity of slag, improving the ability of slag to discharge TiC and TiN, and reducing TiC The accumulation of TiN and TiN in the slag reduces the adsorption of dispersed Ti(C,N) and iron, so that the slag and iron can be separated smoothly, thereby effectively reducing the loss of iron in the finished product and controlling the loss of iron from the source; further, by adjusting The thermal system of smelting provides a more suitable environment for the fluidity of the slag, thereby further reducing the loss of iron in the finished product; it can be seen that the present invention controls the loss of iron through multiple dimensions, and solves the problem of smelting vanadium-titanium magnetite in the existing blast furnace. The method has the problem of serious iron loss, saves production costs and increases economic benefits.

The above embodiment is only one implementation mode of the present invention, and its description is relatively specific and detailed, but it should not be construed as limiting the patent scope of the present invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims (5)

1. A blast furnace smelting method of vanadium titano-magnetite is characterized by comprising the following steps: s1, providing a smelting raw material composition; s2, taking materials according to the raw material composition of the S1, and putting the materials into a blast furnace for distributing to obtain a furnace charge structure; and S3, adjusting a smelting thermal system to carry out smelting and tapping according to preset time to obtain a finished product.

2. The blast furnace smelting method of vanadium titano-magnetite according to claim 1, characterized in that: the raw material composition of the smelting comprises 50-58% of manganese-containing sintered ore, 38-45% of pellet ore and 5-15% of raw ore.

3. The blast furnace smelting method of vanadium titano-magnetite according to claim 2, characterized in that: 0.55 to 0.75% by weight of MnO per part of said manganese-containing sintered ore.

4. The blast furnace smelting method of vanadium titano-magnetite according to claim 1, characterized in that: and the step S3 of adjusting the smelting heat system comprises the step of controlling the content of [ Ti ] + [ Si ] in the molten iron to be 0.25-0.4%.

5. The blast furnace smelting method of vanadium titano-magnetite according to claim 1, characterized in that: and the step 3 of adjusting the smelting heat system comprises setting the furnace temperature to 1430-1500 ℃.

Images