CN107779550B - A method for reducing the addition of molten steel manganese ferroalloy in the refining process - Google Patents

Abstract

The invention relates to a method for reducing the amount of molten steel manganese-ferroalloy added in the refining process, comprising the following steps: step 1, deoxidizing and partially alloying the molten steel during the tapping process of the converter; Station, spray powder into the ladle for manganese ore alloying treatment. The method of the present invention for efficiently reducing the amount of manganese ferroalloy added in molten steel is simple to operate, has good effect, and can directly obtain higher economic benefits; compared with the usual direct alloying of manganese ore, the method of the present invention can obtain direct alloying of manganese ore stably The device and method for manganese yield in chemical process have short reaction time and high manganese yield, and are more suitable for enterprises without refining furnaces.

Description

A method for reducing the addition of molten steel manganese ferroalloy in the refining process

technical field

The invention relates to the technical field of steelmaking, in particular to a method for reducing the addition of molten steel manganese ferroalloy in the refining process.

Background technique

Manganese ore direct alloying technology is to directly add manganese-containing minerals into the steelmaking furnace, and use the elements in the steel or an external reducing agent to reduce the manganese in the minerals, so that the manganese in the manganese ore enters the molten steel to complete the alloying of the molten steel.

Compared with the traditional alloying process, the manganese ore direct alloying process has the following advantages:

(1) The smelting of manganese alloys is omitted, and the melting and reduction of manganese ore are transferred to the steelmaking furnace to complete, thereby saving energy consumption in the process of ferroalloy smelting and alloying;

(2) The smelting of manganese-based alloys is omitted, and the technological process is shortened, thereby reducing environmental pollution and environmental load;

(3) Eliminate and reduce the consumption of manganese alloys, which greatly reduces the cost of alloying and can bring economic benefits to steel plants.

Judging from the application of manganese ore direct alloying technology, this technology is mainly used in the converter steelmaking process. Japanese iron and steel enterprises have carried out direct alloying of manganese ore in the converter on the basis of molten iron pretreatment and smelting with less slag. The yield of manganese is stable at about 70%, which can achieve better economic benefits. However, the actual use effect of domestic iron and steel enterprises is not good, and the yield of manganese is 10% to 60%. low and unstable.

Therefore, finding a new way to alloy manganese ore is particularly important for the application of manganese ore alloying technology.

Contents of the invention

In view of the above analysis, the present invention aims to provide a method for reducing the amount of molten steel manganese ferroalloy added in the refining process, in order to solve the problem of large amount of slag and strong slag oxidation when direct alloying of manganese ore is carried out in the converter in the existing manganese ore direct alloying technology. And cause the manganese yield rate to be low, and the problem of instability.

The purpose of the present invention is mainly achieved through the following technical solutions:

A method for reducing the addition of molten steel manganese ferroalloy in the refining process, comprising the following steps:

Step 1, during the tapping process of the converter, deoxidizing and partially alloying the molten steel;

Step 2. Enter the station at the argon blowing station or LF, spray powder into the ladle for manganese ore alloying treatment.

The beneficial effects of the present invention are as follows: the present invention carries out alloying treatment with the argon blowing station or LF station during the tapping process of the converter, so that a high manganese yield can be obtained, and then higher economic benefits can be obtained.

Further, in the step 1, silicon-manganese, ferrosilicon and recarburizer are added to partially alloy the molten steel when the converter is tapping, and the amount of silicon-manganese added is in the range of 0 to 100kg/t steel; the ferrosilicon The added amount of the carburizing agent ranges from 0 to 100kg/t steel; the added amount of the carburizer ranges from 0 to 90kg/t steel.

The beneficial effect of adopting the above-mentioned further scheme is: the advantage of adding silicomanganese and ferrosilicon in the tapping process of the converter is to increase the manganese content in the molten steel to meet the requirements of the molten steel composition on the manganese content; adding carburization in the tapping process of the converter The benefit of the agent is to increase the content of manganese in molten steel to meet the requirements of molten steel composition; the manganese content in molten steel in the present invention is all added by spraying, which will cause prolonged refining time and serious temperature drop. During the refining process, most of the alloy is added first, and other parts are added during the refining process.

Further, in the step 2, the powder is a mixture of manganese ore powder, lime powder and carbonaceous material, and the addition amount of the mixture ranges from 1 to 50 kg/t of steel.

Adding these mixtures in the present invention can replace 0.1-60% silicon-manganese alloy, and can save production cost by 1-15 yuan/t steel.

Further, in the mixture, by mass percentage, the added amount of the manganese ore powder is 40% to 85%, the added amount of the carbonaceous material is 10% to 40%, and the added amount of the lime powder is 0.1% to 20%; the sum of the mass fractions of the above components is 100%.

The advantage of adding manganese ore powder, carbonaceous material and lime powder in the present invention is to increase the reduction rate of manganese ore, reduce silicon-manganese alloy, and achieve the purpose of reducing energy consumption in the production of silicon-manganese alloy.

Further, in the step 2, the powder is a mixture of manganese ore powder, light-burned dolomite powder and carbonaceous materials, and the addition amount of the mixture ranges from 1 to 50 kg/t steel.

Adding these mixtures in the present invention can replace 0.1-60% silicon-manganese alloy; the benefits of adding manganese ore powder, light-burned dolomite powder and carbonaceous materials in the present invention are to increase the reduction rate of manganese ore, reduce silicon-manganese alloy, and reduce the production of silicon-manganese alloy for energy consumption purposes.

Further, in the mixture, by mass percentage, the added amount of the manganese ore powder is 40% to 85%, the added amount of the carbonaceous material is 10% to 40%, and the added amount of the lightly burned dolomite powder The amount is 0.1% to 20%; the sum of the mass fractions of the above components is 100%.

The manganese ore powder, carbonaceous material, and lightly burned dolomite powder of the present invention can increase the reduction rate of manganese ore, reduce silicon-manganese alloy, and achieve the purpose of reducing energy consumption in the production of silicon-manganese alloy. Corrosion to reduce foreign inclusions into the molten steel.

Further, in the step 2, the powder needs to be dried, crushed, and pulverized before spraying, and the particle size of the powder after pulverization is less than 0.15mm.

The invention has the advantages of drying, crushing and grinding the powder: drying is to reduce the influence of moisture in the mixture on the molten steel, that is, to reduce the hydrogen content; when the crushing and grinding process is performed, sufficient contact between the powders is ensured The composition of the powder and the powder is uniform, which is conducive to the full reduction of manganese ore; the particle size after grinding is less than 0.15mm, that is, less than 100 mesh, in order to ensure sufficient contact between the powder and provide dynamic conditions for the reaction between slag and steel, which is the alloying process of the present invention. Guarantees the smooth progress of the processing.

Further, in the step 2, the powder is sprayed into the side of the ladle through the powder injection unit, the pressure range of the powder injection is controlled at 0.05Mpa-0.55Mpa, and the injection time of the powder is controlled at 1min～15min, the flow range of the powder is controlled at 1kg/min～200kg/min; when spraying the powder, the intensity of the bottom blowing argon gas of the ladle is controlled at 0.003Nm ³ /t.min～0.008Nm ³ / t. min.

In the present invention, the argon blowing at the bottom of the ladle is controlled at 0.003Nm ³ /t.min to 0.008Nm ³ /t.min when the powder is injected. The reaction interface area; the bottom blowing intensity is within 0.008Nm ³ /t.min, the purpose is to prevent the large flow of molten steel from stirring, the molten steel is exposed in the air, absorbs the nitrogen content in the air, causes the nitrogen increase of the molten steel, and affects the quality of the molten steel; The most important control is to ensure that the powder is sprayed into the molten steel smoothly to promote the reduction reaction of manganese ore; the time control is to meet the requirements of the production rhythm.

Further, there are N powder spraying elements, N≥1; the N powder spraying elements are partially or completely embedded in N lining bricks; one end of the N powder spraying elements communicates with the inside of the ladle , for spraying powder on the side of the ladle, the other end of the N powder spraying elements is connected to the external powder supply device through the powder supply channel, and the height of the inlet end of the external powder supply device is higher than the height of the molten steel in the ladle .

The powder spraying element of the present invention has high safety, easy maintenance, simple structure and easy manufacture, and cooperates with bottom-blown inert gas stirring gas to have high reaction efficiency.

Further, the distance between the powder spraying element and the bottom of the ladle is 20%-50% of the total height of the ladle.

The beneficial effects of the present invention are:

(1) the method for efficiently reducing molten steel manganese-ferroalloy addition in a kind of refining process of the present invention is simple to operate, and effect is good, can directly obtain higher economic benefit;

(2) Compared with the usual direct alloying of manganese ore, the device and method thereof for stably obtaining manganese ore direct alloying process manganese yield of the present invention have short reaction times and high manganese yield, and are more suitable for no refining furnace ( LF furnace) enterprises.

In the present invention, the above technical solutions can also be combined with each other to realize more preferred combination solutions. Additional features and advantages of the invention will be set forth in the description which follows, and some of the advantages will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Description of drawings

The drawings are for the purpose of illustrating specific embodiments only and are not to be considered as limitations of the invention, and like reference numerals refer to like parts throughout the drawings.

Fig. 1 is the thermodynamic graph of the relation between the free energy and temperature of Si, C reducing MnO;

Fig. 2 is a safe and efficient ladle side blowing powder refining device in embodiment 1 of the present invention;

Fig. 3 is the arrangement of safe and efficient ladle side blowing powder refining device in embodiment 1 of the present invention;

Fig. 4 is a powder supply device embedded with a plurality of steel pipes with air chambers in the breathable brick of Example 1 of the present invention;

Fig. 5 is a safe and efficient ladle side blowing powder refining device according to Embodiment 2 of the present invention;

Fig. 6 is the layout of safe and efficient ladle side blowing powder refining device in embodiment 2 of the present invention;

Fig. 7 is a powder supply device embedded in a single steel pipe in the breathable brick of Example 2 of the present invention;

Fig. 8 is a safe and efficient ladle side blowing powder refining device according to Embodiment 3 of the present invention;

Fig. 9 is the arrangement of safe and efficient ladle side blowing powder refining device in embodiment 3 of the present invention;

Fig. 10 is a powder supply device embedded in a double-layer casing in the breathable brick of Example 3 of the present invention;

Fig. 11 is a powder supply device in which the air chamber is embedded with multiple steel pipes on the outside and inside the air-permeable brick in Example 4 of the present invention;

In the figure, 1-shell, 2-brick lining, 3-powder supply channel, 4-powder inlet, 5-air chamber, 6-powder supply pipe, 7-single pipe, 8-outer pipe, 9-inner Tube, 10 - inner tube refractory filling.

Detailed ways

Preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the application and together with the embodiments of the present invention are used to explain the principle of the present invention and are not intended to limit the scope of the present invention.

The main principle of the method for reducing the addition of molten steel manganese ferroalloy in a refining process of the present invention is: the main mineral phase composition of manganese ore for metallurgy is calculated by weight percentage: Mn2O3 accounts for ₁₀ % to ₁₅ %; _MnSiO3 accounts for 25% 35%; MnO ₂ accounts for 10-20%; MnCO ₃ accounts for 20-30% and Fe ₃ O ₄ accounts for 10-20%; in these mineral phases, Mn ₂ O ₃ , MnO ₂ and MnCO ₃ are easily Decompose and be reduced to manganese by the carbon in the furnace charge, while the MnSiO ₃ in the manganese ore needs to be reduced at a higher temperature and a reducing atmosphere; and when the content of silicon dioxide in the converter steelmaking slag is high, it is easy to combine with manganese oxide , the manganese silicate produced is difficult to restore, which is the reason for the low yield of manganese in the converter steelmaking manganese ore; at the same time, the manganese ore added in the refining process is also easy to combine with the top slag, if the silica in the top slag High content will also affect the yield of manganese in the refining process.

In order to solve this problem, the present invention considers adding a certain amount of calcium oxide or magnesium oxide (the raw materials of calcium oxide and magnesium oxide are taken from lime and/or lightly burned dolomite) when reducing manganese ore, and the two in manganese silicate The silicon oxide is replaced, and the following reaction occurs:

MnSiO ₃ +CaO=MnO+CaSiO ₃ (1)

MnSiO ₃ +MgO=MnO+MgSiO ₃ (2)

In the process of steelmaking, the carbon content, silicon content and added solid carbon and silicon in molten steel can undergo reduction reaction with (MnO) in molten steel. The chemical reaction formula is as follows:

(MnO)+[C]=[Mn]+CO △ _r G ^θ ＝268904-165.54T (3)

(MnO)+C _(S) ＝[Mn]+CO △ _r G ^θ ＝290684-207.08T (4)

3(MnO)+[Si]=(MnO·SiO ₂ )+2[Mn] △ _r G ^θ ＝-256390+77.77T (5)

3(MnO)+Si _(S) ＝(MnO·SiO ₂ )+2[Mn] △ _r G ^θ ＝-205850+47.77T (6)

It can be calculated from formulas (3)-(6) that it is completely feasible to reduce (MnO) in slag with carbon and silicon at 1400-1700°C from the perspective of thermodynamics. It can be seen from Figure 1 that the refining process at 1550-1700°C , the silicon content of molten steel, ferrosilicon and solid carbon have a strong (MnO) reducing ability, and the existence of these reducing agents ensures that the reduction of manganese ore can be completed in a short period of time.

At the same time, it was also found that it is better to add manganese ore after the converter furnace or in the refining process in steelmaking, because adding manganese ore in the refining process is mainly because manganese ore is beneficial to reduction under reducing conditions, and the slag FeO in the refining process is very low, <1 %; while FeO is higher in the converter or electric furnace process, >10%.

In addition to the research on the selectivity of materials, in terms of technology, the present invention uses the designed device to add the powder made of ore materials and reducing materials into molten steel for reaction. In this field, manganese ore and reducing agents are usually added. It is added in the form of furnace charge from the ladle mouth, lack of stirring, and causes the manganese ore and reducing agent to react with the top slag first, and the iron oxide content in the top slag is high, which affects the recovery rate of manganese ore, and adding more cold material will reduce the molten steel Temperature, entering LF will consume more power.

The present invention can select and operate according to the specific process, steel types and equipment conditions of the steel plant through the above method, and the manganese ore added through the above process into the molten steel can obtain a high manganese yield, and the manganese yield is greater than 90% %.

A specific embodiment of the present invention discloses a method for reducing the amount of ferromanganese alloy added in molten steel during the refining process. The method is tested in a safe and efficient ladle side-blown powder spraying refining device, and the reaction is carried out in a 150t ladle at the same time.

Example 1

In this embodiment, for a 150t ladle, a safe and efficient ladle side-blown powder spraying refining device is used to spray powder into the ladle. A lined brick embedded with a steel pipe with an air chamber with an L of 800mm is used as a powder supply device. One end of the powder supply device is connected to the outside of the shell 1 through a powder supply channel 3, and the powder flows from the outside of the shell 1 to the lined brick 2. It is blown inside to supply powder to the inside of the ladle; it is worth noting that the powder supply channel 3 passes through the cladding 1 through the gap between the cladding 1 and the lining brick 2, and the position where the powder supply channel 3 passes out of the cladding 1 is located at The top of cladding 1, and its position is higher than the upper surface of molten steel, to prevent the leakage of molten steel;

As shown in Figure 3, the distance L between the powder supply device and the bottom of the ladle is 800 mm, the powder injection direction of the powder supply device is horizontal, and the angle α between the device and the ladle trunnion is 60°.

As shown in Figure 4, the powder supply device of this embodiment is composed of a lining brick, a powder inlet, an air chamber and three powder supply pipes, and the powder inlet, air chamber and three powder supply pipes are all embedded in the lining In the brick, at the same time, one end of the powder inlet is connected with one end of the air chamber, the other end is connected with the powder supply channel 3, the other end of the air chamber is connected with three powder supply pipes respectively, and the other end of the three powder supply pipes is connected with The surface of the lining brick is even; it is worth noting that the diameters of the three powder supply pipes are all 10mm.

In this embodiment, 3040 kg of silicon-manganese, 500 kg of ferrosilicon, and 20 kg of recarburizer are added during tapping of the converter. The chemical composition of silicon-manganese is calculated by mass percentage: Si 18.69%, Mn 66.69%, P 0.137%, C 1.43%, S 0.0244 %; After tapping, in the argon blowing station or LF process, use a powder spraying tank to spray a suitable proportion of manganese ore powder, carbon powder, lime powder, and ferrosilicon powder into the ladle through the powder supply device. The composition of the powder is based on the mass The percentages are: 58.34% of manganese ore, 11.67% of lime powder, 23.34% of carbon powder, and 6.65% of ferrosilicon. Grinding as a preparation; the particle size of the mixture after grinding is less than 0.15mm.

Among them, the quality of powder added is 500kg of manganese ore, 57kg of SiFe powder, 200kg of carbon powder, and 100kg of lime powder; Table 1 shows the chemical composition of molten steel at different sampling points.

The purpose of measuring the molten steel composition at different sampling points is to determine the amount of mixed powder added at different stages and the corresponding powder injection speed according to the molten steel composition and target composition at different stages. The advantage of using the device of the invention for powder spraying is to increase the contact area between the powder and molten steel, promote the reaction area between slag and steel, and improve the reduction efficiency of manganese ore.

Table 1 Chemical composition of molten steel at different sampling points

sampling location C/% Si/% Mn/% P/% S/% T/℃ converter end point 0.1 0.001 0.08 0.02 0.015 1690 After tapping 0.13 0.55 1.27 0.021 0.014 1640 After feeding powder 0.21 0.57 1.40 0.022 0.015 1620

The chemical composition of the added raw materials is calculated by mass percentage: ferrosilicon chemical composition: Si 74.51%, Mn 0.12%, P 0.026%, C 0.17%, S 0.007%; carbon powder chemical composition: fixed carbon 93.67%, P 0.015%, S 0.21%; Lime: CaO 82.78%, SiO ₂ : 3.11%, MgO 7.99%, Al ₂ O ₃ 1.19%, S 0.030%, P 0.006%; Chemical composition of manganese ore: TMn 42.8%, SiO ₂ 16%, TFe 11.6 %, P 0.13%, S 0.016%. Because there are some other impurities in silicomanganese, ferrosilicon, carbon powder and lime, the total amount of general components cannot reach 100%.

In this embodiment, the tapping temperature is controlled at 1620° C., the injection pressure is 0.18-0.22 Mpa, the powder injection flow rate is 100 kg/min, and the injection time is 5 minutes.

In this example, using the device of the present invention for powder spraying can increase the manganese content by 0.13%, the manganese yield rate is 91.1%, and the cost is saved by 3.0 yuan/ton of steel.

Example 2

In this embodiment, for a 150t ladle, a safe and efficient ladle side blowing powder spraying refining device is used to spray powder into the ladle. Two lining bricks embedded with steel pipes with air chambers with L of 800mm are used as powder supply devices, which supply air to the inside of the ladle respectively; the two powder supply devices have the same structure, that is, one end of the powder supply device passes through the outside of the cladding 1 The powder supply channel 3 is connected, and the powder is blown from the outside of the shell 1 to the inside of the lining brick 2 to supply powder to the inside of the ladle; it is worth noting that the powder supply channel 3 passes through the gap between the shell 1 and the lining brick 2 The cladding 1, and the position where the powder supply channel 3 passes through the cladding 1 is located on the top of the cladding 1, and its position is higher than the upper surface of the molten steel to prevent leakage of molten steel;

As shown in Figure 6, the distance L between the powder supply device and the bottom of the ladle is 800mm, the powder spraying direction of the two powder supply devices is at an angle of 15° to the horizontal direction β, and the angle between the two powder supply devices and the ladle trunnion is α 45° and 135° respectively. It is worth noting that the blowing directions of the two powder supply devices in this embodiment can be different, one can be 15°, and the other can be -15°.

As shown in Figure 7, each powder supply device in this embodiment consists of a lining brick and a single tube, the single tube is embedded in the lining brick, and one end of the single tube is connected with the powder supply channel 3, and the single tube The other end of the tube is flush with the surface of the lining brick and supplies powder to the ladle; it is worth noting that the diameter of the single tube is 12mm.

In this embodiment, 2980 kg of silicomanganese, 600 kg of ferrosilicon, and 30 kg of recarburizer are added during tapping of the converter. After the steel is tapped, in the argon blowing station or LF process, spray a suitable proportion of manganese ore powder, light burnt dolomite powder, lime powder and ferrosilicon powder into the ladle with a powder spray tank. The composition of the powder is: 55.56% of manganese ore, Lightly burned dolomite powder 14.77%, carbon powder 27.78%, and ferrosilicon 7.41% are used as a powder, in which 600kg of manganese ore, SiFe powder 80kg, carbon powder 300kg, lightly burned dolomite powder 100kg, manganese ore of each composition before mixing , lightly burned dolomite powder, and carbon powder are dried, crushed, and ground as raw materials.

Table 2 shows the chemical composition of molten steel at different sampling points.

Table 2 Chemical composition of molten steel at different sampling points

sampling location C/% Si/% Mn/% P/% S/% T/℃ converter end point 0.12 0.003 0.07 0.018 0.010 1700 After tapping 0.15 0.59 1.23 0.019 0.011 1650 After feeding powder 0.26 0.61 1.39 0.022 0.010 1620

The chemical composition of the added raw materials is calculated by mass percentage: silicon-manganese chemical composition: Si 18.69%, Mn66.69%, P 0.137%, C 1.43%, S 0.0244%; ferrosilicon chemical composition: Si 74.51%, Mn 0.12%, P0.026%, C 0.17%, S 0.007%; carbon powder chemical composition: fixed carbon 93.67%, P 0.015%, S 0.21%; lightly burned dolomite: CaO 45.0%, SiO ₂ : 2.15%, MgO 38%, Combustion reduction 14.2%, S 0.030%, P 0.03%; manganese ore chemical composition: TMn 42.8%, SiO ₂ 16%, TFe 11.6%, P 0.13%, S 0.016%.

In this embodiment, the tapping temperature is controlled at 1620° C., the injection pressure is 0.18-0.22 Mpa, the powder injection flow rate is 100 kg/min, and the injection time is 6 minutes.

In this example, using the device of the present invention for powder spraying can increase the manganese content by 0.16%, the manganese yield rate is 93.5%, and the cost is saved by 3.5 yuan/ton of steel.

Example 3

In this embodiment, for a 150t ladle, a safe and efficient ladle side-blown powder spraying refining device is used to spray powder into the ladle. Three lining bricks embedded with steel pipes with air chambers with L of 800mm are used as powder supply devices, which supply air to the inside of the ladle respectively; the three powder supply devices have the same structure, that is, one end of the powder supply device passes through the outside of the cladding 1 The powder supply channel 3 is connected, and the powder is blown from the outside of the shell 1 to the inside of the lining brick 2 to supply powder to the inside of the ladle; it is worth noting that the powder supply channel 3 passes through the gap between the shell 1 and the lining brick 2 The cladding 1, and the position where the powder supply channel 3 passes through the cladding 1 is located on the top of the cladding 1, and its position is higher than the upper surface of the molten steel to prevent leakage of molten steel;

As shown in Figure 9, the distance L between the powder supply device and the bottom of the ladle is 800mm, the powder injection direction of the three powder supply devices is at an angle of -15° with the horizontal direction, and the angle between the three powder supply devices and the steel ladle trunnion is α They are 45°, -45° and 135° respectively.

As shown in Figure 10, each powder supply device in this embodiment consists of a lining brick and a double-layer casing, the double-layer casing is embedded in the lining brick, and one end of the double-layer casing is connected to the powder supply The channel 3 is connected, and the other end of the double-layer casing is flush with the surface of the lining brick to supply powder to the ladle; it is worth noting that the double-layer casing includes an inner pipe and an outer pipe, the inner pipe is located inside the outer pipe, and the inner The tube is filled with refractory filler, the outer diameter is 22 mm, and the inner tube diameter is 10 mm. In this embodiment, a double-layer casing is selected. The advantage of using a double-layer casing is that if one pipe is blocked, it will not affect the overall blowing effect.

In this embodiment, 3080 kg of silicon-manganese, 600 kg of ferrosilicon, and 20 kg of recarburizer are added when tapping the converter. powder, lime powder and ferrosilicon. The composition of the powder is: 52.25% manganese ore, 10.45% lime powder, 31.35% carbon powder, and 5.96% ferrosilicon. , carbon powder 300kg, lime 100kg, manganese ore, lime powder and carbon powder are dried, crushed and ground before mixing. The particle size after grinding is less than 0.15mm (within 100 mesh), so as to ensure that the powder is mixed evenly; the ferrosilicon powder is used, which needs to be dried and does not need to be ground.

Table 3 shows the chemical composition of molten steel at different sampling points.

Table 3 Chemical composition of molten steel at different sampling points

sampling location C/% Si/% Mn/% P/% S/% T/℃ converter end point 0.08 0.002 0.10 0.015 0.010 1690 After tapping 0.11 0.60 1.30 0.015 0.010 1630 After feeding powder 0.22 0.62 1.43 0.018 0.011 1600

The chemical composition of the added raw materials is calculated by mass percentage: silicon-manganese chemical composition: Si 18.69%, Mn66.69%, P 0.137%, C 1.43%, S 0.0244%; ferrosilicon chemical composition: Si 74.51%, Mn 0.12%, P0.026%, C 0.17%, S 0.007%; carbon powder chemical composition: fixed carbon 93.67%, P 0.015%, S 0.21%; lime: CaO 82.78%, SiO ₂ : 3.11%, MgO 7.99%, Al ₂ O ₃ 1.19%, S 0.030%, P 0.006%; chemical composition of manganese ore: TMn 42.8%, SiO ₂ 16%, TFe 11.6%, P 0.13%, S 0.016%.

In this embodiment, the tapping temperature is controlled at 1600° C., the injection pressure is 0.18-0.22 Mpa, the powder injection flow rate is 100 kg/min, and the injection time is 5 minutes.

In this example, using the device of the present invention for powder spraying can increase the manganese content by 0.13%, the manganese yield rate is 91.1%, and the cost is saved by 3.0 yuan/ton of steel.

Example 4

In this embodiment, for a 150t ladle, a safe and efficient ladle side blowing powder spraying refining device is used to spray powder into the ladle. As shown in Figure 2, a lining brick 2 is built inside the cladding 1 of the ladle, and the A lining brick with an L of 800mm embedded in a steel pipe with an air chamber is used as a powder supply device. One end of the powder supply device is connected to the outside of the shell 1 through a powder supply channel 3, and the powder flows from the outside of the shell 1 to the lining brick 2. It is blown inside to supply powder to the inside of the ladle; it is worth noting that the powder supply passage 3 passes through the cladding 1 through the gap between the cladding 1 and the lining brick 2, and the position where the powder supply passage 3 passes through the cladding 1 is located at The top of cladding 1, and its position is higher than the upper surface of molten steel, to prevent the leakage of molten steel;

As shown in Figure 3, the distance L between the powder supply device and the bottom of the ladle is 800 mm, the powder injection direction of the powder supply device is horizontal, and the angle α between the device and the ladle trunnion is 60°.

As shown in Figure 11, the powder supply device of this embodiment is composed of a lining brick, a powder inlet, an air chamber and 3 powder supply pipes, and the 3 powder supply pipes are embedded in the lining brick, and the powder inlet and The air chamber is not embedded in the lining brick. At the same time, one end of the powder inlet is connected to one end of the air chamber, and the other end is connected to the powder supply channel 3. The other end of the air chamber is connected to three powder supply pipes respectively. The other end of the powder pipe is flush with the surface of the lining brick; it is worth noting that the diameter of the three powder supply pipes is 10mm.

In this embodiment, 3000 kg of silicon manganese, 580 kg of ferrosilicon, and 20 kg of recarburizing agent are added during tapping of the converter. After tapping, manganese ore powder, lightly burned dolomite powder, lightly burned dolomite powder, Powder composed of carbon powder and ferrosilicon. The composition of the powder is: 52.17% of manganese ore, 8.70% of lightly burned dolomite powder, 30.43% of carbon powder, and 8.70% of ferrosilicon. , carbon powder 350kg, light-burned dolomite powder 100kg, manganese ore, light-burned dolomite powder, and carbon powder were dried, crushed and ground before mixing as preparation materials.

Table 4 shows the chemical composition of molten steel at different sampling points.

Table 4 Chemical composition of molten steel at different sampling points

sampling location C/% Si/% Mn/% P/% S/% T/℃ converter end point 0.08 0.004 0.08 0.017 0.008 1690 After tapping 0.11 0.59 1.25 0.017 0.007 1630 After feeding powder 0.24 0.61 1.41 0.021 0.008 1590

The chemical composition of the added raw materials is calculated by mass percentage: silicon-manganese chemical composition: Si 18.69%, Mn66.69%, P 0.137%, C 1.43%, S 0.0244%; ferrosilicon chemical composition: Si 74.51%, Mn 0.12%, P0.026%, C 0.17%, S 0.007%; carbon powder chemical composition: fixed carbon 93.67%, P 0.015%, S 0.21%; lime: CaO 82.78%, SiO ₂ : 3.11%, MgO 7.99%, Al ₂ O ₃ 1.19%, S 0.030%, P 0.006%; chemical composition of manganese ore: TMn 42.8%, SiO ₂ 16%, TFe 11.6%, P 0.13%, S 0.016%.

In this embodiment, the tapping temperature is controlled at 1590° C., the injection pressure is 0.18-0.22 Mpa, the powder injection flow rate is 100 kg/min, and the injection time is 6 minutes.

In this example, using the device of the present invention for powder spraying can increase the manganese content by 0.16%, the manganese yield rate is 93.5%, and the cost is saved by 3.5 yuan/ton of steel.

Example 5

The powder spraying device that adopts in the present embodiment is identical with embodiment 1.

In the argon blowing station or LF process, spray the powder composed of lime powder and fluorite in a suitable proportion with a powder spray tank. Before mixing, the lime and fluorite powder are dried, crushed, and ground as raw materials. The particle size after grinding Less than 0.15mm, the composition of the powder is: lime powder accounts for 90%, fluorite powder accounts for 10%, and the weight of the sprayed powder is 600kg.

Table 5 shows the chemical composition of molten steel at different sampling points.

Table 5 Chemical composition of molten steel at different sampling points

sampling location C/% Si/% Mn/% P/% S/% T/℃ After converter tapping 0.18 0.55 1.20 0.021 0.038 1680 After dusting 0.19 0.54 1.20 0.022 0.018 1630

After tapping the converter, the temperature is 1680°C, the powder injection pressure is 0.18-0.22Mpa, the powder injection flow rate is 120kg/min, and the injection time is 5min; the ladle bottom blowing intensity is 0.008Nm ³ /t.min.

The desulfurization rate of the molten steel after treatment is: (0.038%-0.018%)/0.038%×100%=53%, and the temperature of the molten steel drops to 50°C.

Example 6

The powder spraying device adopted in this embodiment is the same as that in Embodiment 2.

After the converter is tapped, in the argon blowing station, a powder consisting of manganese ore powder, coke powder, and limestone powder is sprayed with a powder spray tank in a suitable proportion. Before mixing, the manganese ore, limestone powder, and coke powder are dried, crushed, Grinding is used as a raw material, and the particle size after grinding is less than 0.15mm. The composition of the powder is: 60% of manganese ore, 15% of limestone powder, and the mixture made of 25% of coke is used as powder, and the weight of the powder is 1000kg.

Table 6 shows the chemical composition of molten steel at different sampling points.

Table 6 Chemical composition of molten steel at different sampling points

sampling location C/% Si/% Mn/% P/% S/% T/℃ After converter tapping 0.18 0.59 1.23 0.019 0.011 1660 After dusting 0.27 0.62 1.37 0.021 0.010 1630

The chemical composition of added manganese ore is: TMn 42.8%, SiO ₂ 16%, TFe 11.6%, P 0.13%, S0.016%; coke powder chemical composition: fixed carbon 93.67%, P 0.015%, S 0.21%.

After tapping the converter, the temperature is 1660°C, the injection pressure is 0.18-0.24Mpa, the powder injection flow rate is 160kg/min, the injection time is 7min, and the ladle bottom blowing argon intensity is 0.008Nm ³ /t.min; after treatment, The manganese yield of molten steel was 82%.

Wherein the calculation formula of manganese yield ηMn is:

In the formula: M is the weight of molten steel, kg; m is the added weight of manganese ore, kg; α is the content of TMn in manganese ore, %; w([Mn]) _i is the initial manganese content of molten steel, %; w([Mn])f is Manganese content in molten steel at the end point, %.

Example 7

The powder spraying device adopted in this embodiment is the same as that in Embodiment 3.

After the converter is tapped, in the argon blowing station, a powder consisting of chrome ore powder, anthracite and lime powder with a suitable proportion is sprayed into the argon blowing station. Before mixing, the chromium ore powder, lime powder and anthracite powder are dried, Crushing and grinding are used as raw materials, and the particle size after grinding is less than 0.15mm. The composition of the powder is: 70% of chrome ore powder, 10% of lime powder, and 20% of anthracite powder.

Table 7 shows the chemical composition of molten steel at different sampling points.

Table 7 Chemical composition of molten steel at different sampling points

sampling location C/% Si/% Mn/% Cr/% P/% S/% T/℃ After converter tapping 0.21 0.52 1.21 0.02 0.019 0.011 1680 After feeding powder 0.24 0.55 1.22 0.14 0.021 0.014 1640

The chemical composition of the added chrome ore is: Cr ₂ O ₃ 46.13%; CaO 0.4%; SiO ₂ 6.28%; C 0.074%; MgO 16.17%; TFe 15.04%; _FeO 1.03% _;

After tapping the converter, the temperature is 1640°C, the injection pressure is 0.18-0.23Mpa, the powder injection flow rate is 130kg/min, the injection time is 6min, and the intensity of argon blowing at the bottom of the ladle is 0.007Nm ³ /t.min; after treatment, The chromium yield of molten steel is 70%.

Wherein the calculation formula of chromium yield η _Cr is:

In the formula: M is the weight of molten steel, kg; m is the added weight of chrome ore, kg; α is the content of TMn in chrome ore, %; w([Cr]) _i is the initial manganese content of molten steel, %; w([Cr]) _f is the manganese content of the end point molten steel, %.

Example 8

The powder spraying device adopted in this embodiment is the same as that in Embodiment 4.

At the RH exit station, a powder consisting of magnesium-silicon-iron powder and limestone powder with a suitable ratio is sprayed with a powder spraying tank. Before mixing, the magnesium-silicon-iron powder and limestone powder are dried, crushed, and ground as raw materials. The particle size after grinding is less than 0.15mm, and the composition of the powder is: 90% of magnesium-silicon-iron powder, 10% of limestone powder, and the added weight is 15kg.

Table 8 shows the chemical composition of molten steel at different sampling points.

Table 8 Chemical composition of molten steel at different sampling points

sampling location C/% Si/% Mn/% Mg/% Ti/% P/% S/% T/℃ Before powder feeding 0.15 0.40 1.34 0 0.001 0.016 0.009 1600 After feeding powder 0.15 0.41 1.32 0.0018 0.010 0.015 0.008 1590

The chemical composition of the raw materials added is: Mg in magnesium-silicon-iron powder accounts for 30%, silicon accounts for 35%, and the rest is iron and impurities. It is 20kg/min, the injection time is 1min, and the yield of metal magnesium is 66%.

Wherein the calculation formula of magnesium yield η _Mg is:

In the formula: M is the weight of molten steel, kg; m is the added weight of magnesium-silicon-iron, kg; α is the Mg content in magnesium-silicon-iron, %; w([Mg]) _i is the initial manganese content of molten steel, %; w([Mg]) _f is the manganese content of the end point molten steel, %.

In summary, the present invention provides a method for reducing the addition of molten steel manganese ferroalloy in the refining process. Compared with the traditional method of adding through the top, the method of side blowing spray agent of the present invention has the advantages of fast slag-gold reaction speed, The reaction time is short, and the effect of desulfurization and removal of inclusions in steel is good.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present invention can easily think of changes or Replacement should be covered within the protection scope of the present invention.

Claims (5)

1. a method for reducing molten steel manganese-ferroalloy addition in a refining process, is characterized in that, may further comprise the steps: Step 1, during the tapping process of the converter, deoxidizing and partially alloying the molten steel; Step 2. In the argon blowing station or LF station, spray powder into the ladle for manganese ore alloying treatment; In the step 1, silicon-manganese, ferrosilicon and recarburizer are added to partially alloy the molten steel when the converter is tapping, and the amount of silicon-manganese to be added ranges from 0 to 100 kg/t of steel; the addition of the ferrosilicon The amount ranges from 0 to 100kg/t steel; the added amount of the recarburizer ranges from 0 to 90kg/t steel; In the step 2, the powder is a mixture of manganese ore powder, lime powder and carbonaceous material, and the amount of the mixture is 1 to 50 kg/t of steel; or, in the step 2, the powder is manganese ore powder, light-burned dolomite powder and a mixture of carbonaceous materials, the addition of the mixture ranges from 1 to 50kg/t steel; In the step 2, the powder is sprayed into the side of the ladle through a powder spraying element, the pressure range of the powder injection is controlled at 0.05Mpa to 0.55Mpa, and the injection time of the powder is controlled at 1min to 15min , the flow range of the powder is controlled at 1kg/min～200kg/min; when the powder is injected, the intensity of the bottom blowing argon gas of the ladle is controlled at 0.003Nm ³ /t.min～0.008Nm ³ /t.min ; There are N powder spraying elements, N≥1; the N powder spraying elements are partially embedded in N lining bricks; one end of the N powder spraying elements is connected to the inside of the ladle, and is the ladle The powder is sprayed on the side, the other ends of the N powder spraying elements are connected to the external powder supply device through the powder supply channel, and the height of the inlet end of the external powder supply device is higher than the height of the molten steel in the ladle; The powder spraying element is composed of a lining brick, a powder inlet, an air chamber and 3 powder supply pipes, and the 3 powder supply pipes are embedded in the lining brick, while the powder inlet and the air chamber are not embedded in the lining In the brick, at the same time, one end of the powder inlet is connected to one end of the air chamber, the other end is connected to the powder supply channel, the other end of the air chamber is connected to three powder supply pipes, and the other end of the three powder supply pipes is connected to the lining The surface of the brick is flush. 2. the method for reducing the addition of molten steel manganese ferroalloy in a kind of refining process according to claim 1, is characterized in that, in described mixture, by mass percentage, the addition of described manganese ore powder is 40%～85% , the added amount of the carbonaceous material is 10%-40%, the added amount of the lime powder is 0.1%-20%; the sum of the mass fractions of the above components is 100%. 3. the method for reducing the addition of molten steel manganese ferroalloy in a kind of refining process according to claim 1, is characterized in that, in described mixture, by mass percentage, the addition of described manganese ore powder is 40%～85% , the added amount of the carbonaceous material is 10%-40%, the added amount of the light-burned dolomite powder is 0.1%-20%; the sum of the mass fractions of the above-mentioned components is 100%. 4. the method for reducing the addition of molten steel manganese ferroalloy in a kind of refining process according to claim 1, is characterized in that, in described step 2, described powder needs to be dried, crushed, pulverized before spraying into , the particle size of the powder after milling is less than 0.15mm. 5. the method for reducing molten steel manganese-ferroalloy addition in a kind of refining process according to claim 1, is characterized in that, described powder spray element is arranged at the percentage that accounts for described steel ladle total height with the distance of described ladle bottom 20% to 50%.