TWI762226B - Preparation method of desulfurizer for steelmaking - Google Patents

Abstract

A preparation method of a desulfurizing agent for steelmaking, comprising the following steps: step (a), mixing calcium oxide and aluminum oxide, and sequentially performing melting treatment and cooling treatment to form aluminum containing dodecacalcium heptaaluminate and, in step (b), the calcium aluminate component, refining slag, calcium oxide, magnesium oxide and calcium fluoride are mixed and processed to form a composition comprising dodecacalcium heptaaluminate, calcium oxide, and calcium oxide. Desulfurizer for steelmaking of silicon, aluminum oxide, magnesium oxide and calcium fluoride. Taking the total amount of the desulfurizer for steelmaking as 100wt%, the total content of calcium oxide, silicon dioxide, aluminum oxide, magnesium oxide and calcium fluoride is 45 to 60wt%, 5 to 15wt%, 15 to 30 wt%, 0 to 10 wt%, and 5 to 15 wt%. The desulfurizing agent for steelmaking prepared by the method for preparing the desulfurizing agent for steelmaking of the present invention has the advantage of a desulfurization rate of more than 80%.

Description

Preparation method of desulfurizer for steelmaking

The invention relates to a preparation method of a desulfurizing agent, in particular to a preparation method of a desulfurizing agent for steelmaking using calcium aluminate components and refining slag.

Due to the increasing use of steel, the requirements for steel performance are also increasing. One of the key technologies to improve steel performance is to improve the purity of molten steel, especially to reduce the sulfur content in the molten steel. Therefore, How to reduce the sulfur content in molten steel is a widely studied topic. In general, most methods for reducing the sulfur content in molten steel are performed by using a desulfurizing agent.

The Republic of China Patent Publication No. 602925 discloses a desulfurizer for steelmaking and a method for preparing the desulfurizer. The desulfurizer contains 30-50 parts by weight of refining slag and 50-70 parts by weight of supplementary materials. The refining slag includes calcium oxide, silicon oxide, aluminum oxide, magnesium oxide and calcium fluoride, and the supplementary material includes calcium oxide, aluminum oxide and silicon oxide. The preparation method of the desulfurizing agent is to mix the refining slag and the supplementary material, then heat up until the refining slag and the supplementary material are completely melted and liquefied, and then cool to room temperature.

Although the preparation method of the desulfurizing agent in this patent case can produce a desulfurizing agent with a desulfurization rate of 57.6-77.5% after desulfurizing a molten steel for 20 minutes, however, in the face of today's requirements for steel performance Increasingly, the desulfurization rate still does not meet the needs of the steel industry.

Therefore, the object of the present invention is to provide a method for preparing a desulfurizing agent for steelmaking capable of preparing a desulfurizing agent for steelmaking having a desulfurization rate of 80% or more.

Therefore, the preparation method of the desulfurizer for steelmaking of the present invention comprises the following steps: step (a), mixing calcium oxide (CaO) and aluminum oxide (A1 ₂ O ₃ ), and sequentially performing melting treatment and cooling processing to form a calcium aluminate component comprising dodecacalcium heptaaluminate; and, step (b), the calcium aluminate component, refining slag, calcium oxide, magnesium oxide (MgO) and calcium fluoride (CaF ₂ ) is mixed to form a desulfurizer for steelmaking comprising dodecacalcium heptaaluminate, calcium oxide, silicon dioxide (SiO ₂ ), aluminum oxide, magnesium oxide and calcium fluoride. Based on the total amount of the desulfurizer for steelmaking being 100wt%, the total content range of the calcium oxide is 45wt% to 60wt%, the total content range of the silicon dioxide is 5wt% to 15wt%, the aluminum oxide The total content of the magnesium oxide ranges from 15 wt % to 30 wt %, the total content of the magnesium oxide ranges from 0 wt % to 10 wt %, and the total content of the calcium fluoride ranges from 5 wt % to 15 wt %.

The effect of the present invention is: by mixing the calcium aluminate component, calcium oxide, magnesium oxide and calcium fluoride with the refining slag, the preparation method of the desulfurizing agent for steelmaking of the present invention enables the refining slag to be recycled and reused, and simultaneously , and can also prepare a desulfurizing agent for steelmaking with a desulfurization rate of more than 80%.

The preparation method of the desulfurizer for steelmaking of the present invention comprises the following steps: step (a), mixing calcium oxide and aluminum oxide, and sequentially performing melting treatment and cooling treatment to form aluminum containing dodecacalcium heptaaluminate Calcium acid component; Step (b), the calcium aluminate component, refining slag, calcium oxide, magnesium oxide and calcium fluoride are mixed to form a composition comprising dodecacalcium heptaaluminate, calcium oxide, silicon dioxide, A desulfurizing agent for steelmaking of aluminum oxide, magnesium oxide and calcium fluoride, and based on the total amount of the desulfurizing agent for steelmaking being 100wt%, the total content of the calcium oxide ranges from 45wt% to 60wt%, The total content of the silicon dioxide is in the range of 5wt% to 15wt%, the total content of the aluminum oxide is in the range of 15wt% to 30wt%, the total content of the magnesium oxide is in the range of 0wt% to 10wt%, and the calcium fluoride is in the range of 0wt% to 10wt%. The total content ranges from 5wt% to 15wt%.

The content of the present invention will be described in detail below.

<Step (a)>

In some embodiments of the method for preparing a desulfurizing agent for steelmaking of the present invention, based on the total amount of the calcium oxide and the aluminum oxide being 100 wt %, the content of the calcium oxide ranges from 40 wt % to 60 wt %. In some embodiments of the method for preparing a desulfurizing agent for steelmaking of the present invention, based on the total amount of the calcium oxide and the aluminum oxide being 100 wt %, the content of the aluminum oxide ranges from 40 wt % to 60 wt % %.

[melt processing]

In some embodiments of the method for preparing a desulfurizing agent for steelmaking of the present invention, the temperature range of the melting treatment is 1400° C. or higher.

[shredding treatment]

In some embodiments of the method for preparing a desulfurizer for steelmaking of the present invention, the method further comprises performing a crushing treatment on the calcium aluminate component to form a crushed calcium aluminate component. In some embodiments of the method for preparing a desulfurizer for steelmaking of the present invention, the particle size of the crushed calcium aluminate component ranges from 0.3 mm to 1 mm.

<Step (b)>

In some embodiments of the method for preparing a desulfurizing agent for steelmaking of the present invention, based on the total amount of the desulfurizing agent for steelmaking being 100 wt %, the content of dodecacalcium heptaaluminate in the calcium aluminate component The range is 35wt% to 50wt%.

In the preparation method of the desulfurizing agent for steelmaking of the present invention, the refining slag is used to prepare the desulfurizing agent for steelmaking, so that the refining slag can be recycled and reused, thereby reducing the pollution of the refining slag to the environment, and at the same time, reducing the number of iron and steel plants. The waste of the refining slag is processed into powder. Furthermore, most of the current desulfurizers contain calcium oxide, and the refining slag itself also contains calcium oxide. Therefore, the amount of fresh calcium oxide used in the desulfurizer can be reduced. Thereby reducing the cost of the desulfurizer. In some embodiments of the method for preparing a desulfurizing agent for steelmaking of the present invention, based on the total amount of the desulfurizing agent for steelmaking being 100 wt%, the content of the refining slag ranges from 30 wt% to 50 wt%.

In the present invention, the dodecacalcium heptaaluminate contains calcium oxide and the refining slag also contains calcium oxide, and at the same time, calcium oxide is also added in step (b), based on this, the calcium oxide of the desulfurizer for steelmaking The total content includes the content of calcium oxide in the dodecacalcium heptaaluminate, the content of calcium oxide in the refining slag, and the content of calcium oxide in step (b).

In the present invention, the dodecacalcium heptaaluminate contains aluminum oxide and the refining slag also contains aluminum oxide. Based on this, the total content of aluminum oxide in the desulfurizing agent for steelmaking includes the hepta aluminum. The content of aluminum oxide in dodecacalcium acid and the content of aluminum oxide in the refining slag.

In order to make the desulfurizing agent for steel making can be directly put into molten steel, to shorten the input time and improve the convenience of operation, in some embodiments of the preparation method of the desulfurizing agent for steel making of the present invention, it is also included in the step ( After the mixing treatment in b), a pressing treatment is carried out.

[Pressure treatment]

In some embodiments of the method for preparing a desulfurizing agent for steelmaking of the present invention, the time of the pressing treatment is 90 seconds. In order to prevent the desulfurizing agent for steelmaking of the present invention from being broken after being dropped from a height of one meter, in some embodiments of the method for preparing the desulfurizing agent for steelmaking of the present invention, the time of the pressing treatment is At 90 seconds, the pressure range of the pressing treatment was 2t/cm ² to 3t/cm ² .

In order to facilitate the carrying out of the pressing process and to prepare a bulk desulfurizer for steelmaking that can not be broken during transportation, there are some embodiments of the method for preparing a desulfurizer for steelmaking of the present invention. In the step (b), an adhesive is added to carry out the mixing treatment. The adhesive is, for example, but not limited to, sodium silicate or calcium hydroxide (commonly known as slaked lime). In order to reduce the unnecessary influence of the adhesive on the components in the desulfurizer for steelmaking, in some embodiments of the method for preparing the desulfurizer for steelmaking of the present invention, the adhesive is calcium hydroxide. In some embodiments of the method for preparing a desulfurizing agent for steelmaking of the present invention, based on the total amount of the desulfurizing agent for steelmaking being 100 wt%, the content of the adhesive ranges from 1 wt% to 5 wt%.

[Drying treatment]

In order to enable the water content of the desulfurizing agent for steelmaking of the present invention to be less than 1.5 wt %, so as to be used in steelmaking, in some embodiments of the preparation method of the desulfurizing agent for steelmaking of the present invention, it is also included in the Drying treatment is carried out after pressing treatment. In some embodiments of the method for producing a desulfurizing agent for steelmaking of the present invention, the drying treatment is performed by heating. In some embodiments of the method for preparing a desulfurizing agent for steelmaking of the present invention, the temperature of the drying treatment ranges from 110°C to 120°C, and the time ranges from 0.5 hour to 1 hour.

＜Desulfurizer for steelmaking＞

Generally, most of the recovered refining slag contains dicalcium silicate (Ca ₂ SiO ₄ , C ₂ S for short), which is not conducive to reducing the sulfur content in molten steel. In the present invention, through the calcium aluminate component, calcium oxide, Magnesium oxide and calcium fluoride are mixed with refining slag, so that the obtained desulfurizer for steelmaking does not contain dicalcium silicate, so that the desulfurization rate of the desulfurizer for steelmaking of the present invention is not affected by the presence of dicalcium silicate. Therefore, in the present invention, the refining slag containing dicalcium silicate can be selected, so that the refining slag containing dicalcium silicate can be recycled and reused.

In some embodiments of the method for preparing a desulfurizing agent for steelmaking of the present invention, based on the total amount of the desulfurizing agent for steelmaking being 100 wt %, the total content of calcium oxide ranges from 47 wt % to 53 wt %. The total content of silicon dioxide ranges from 6 wt % to 11 wt %, the total content of the aluminum oxide ranges from 22 wt % to 30 wt %, the total content of the magnesium oxide ranges from 2 wt % to 5 wt %, and the total content of the calcium fluoride ranges from 2 to 5 wt %. The total content ranges from 7wt% to 12wt%.

Since the preparation method of the desulfurizing agent for steelmaking according to the present invention can obtain the desulfurizing agent for steelmaking that does not contain dicalcium silicate, and the desulfurizing agent for steelmaking is used for desulfurizing the molten steel containing sulfur, the It will produce dodecacalcium heptaaluminate, which is more helpful to improve the desulfurization rate.

The present invention will be further described with respect to the following examples, but it should be understood that these examples are only used for illustration and should not be construed as a limitation of the implementation of the present invention.

Example 1 Preparation method of desulfurizer for steelmaking

49wt% calcium oxide was mixed with 51wt% aluminum oxide and heated to 1400°C to make the calcium oxide and the aluminum oxide in a molten state, and then cooled to room temperature to form 42 grams containing heptaaluminum A calcium aluminate component of dodecacalcium acid, and then, the calcium aluminate component is subjected to a crushing treatment to form a powdered calcium aluminate component with a particle size of 0.3 mm to 1 mm.

The powdered calcium aluminate component, 30 grams of refining slag (source: refining slag from Taiwan Electric Arc Furnace Steel Plant; with dicalcium silicate crystal phase; components: 0.6wt% sulfur, 51.3wt% CaO, 23.1 wt % SiO ₂ , 15.0 wt % MgO, 7.0 wt % A1 ₂ O ₃ , and 3.0 wt % CaF ₂ ), 6 g calcium oxide, 8 g calcium fluoride, and 4.3 g calcium hydroxide Mixed and processed to form a desulfurizer for steelmaking, and then the desulfurizer for steelmaking was placed in a die of a press (brand: Xinji Machinery Co., Ltd.; model: 02OPM-1001) for pressing Anchoring treatment is performed to form a rough embryo of the desulfurizer for bulk steelmaking, wherein the pressure of the anchoring treatment is 2t/cm ² to 3t/cm ² , and the time is 90 seconds.

The crude desulfurizer for bulk steelmaking was put into an oven set at a temperature of 110°C to 120°C for 30 minutes of drying to obtain 89.4 g of desulfurizer for bulk steelmaking.

Example 2

49wt% calcium oxide was mixed with 51wt% aluminum oxide and heated to 1400°C to make the calcium oxide and the aluminum oxide in a molten state, then cooled to room temperature to form 40 grams containing heptaaluminum A calcium aluminate component of dodecacalcium acid, and then, the calcium aluminate component is subjected to a crushing treatment to form a powdered calcium aluminate component with a particle size of 0.3 mm to 1 mm.

The powdered calcium aluminate component, 40 grams of refining slag (source: refining slag from Taiwan electric arc furnace steel plant; with dicalcium silicate crystal phase; composition: 0.7wt% sulfur, 53.7wt% CaO, 16.1 wt % SiO ₂ , 4.9 wt % MgO, 16.5 wt % Al ₂ O ₃ , and 8.1 wt % CaF ₂ ), 4.6 grams of calcium oxide, 4 grams of calcium fluoride, 2 grams of magnesium oxide, and 4.0 grams of calcium hydroxide was mixed to form a desulfurizing agent for steelmaking, and then the desulfurizing agent for steelmaking was placed in a press (brand: Xinji Machinery Co., Ltd.; model: 02OPM-1001 ) in one of the molds for pressing treatment to form a rough preform of the desulfurizer for bulk steelmaking, wherein the pressing treatment pressure is 2t/cm ² to 3t/cm ² and the time is 90 seconds.

The crude desulfurizer for bulk steelmaking was put into an oven set at a temperature of 110°C to 120°C for 30 minutes of drying to obtain 83.8 g of desulfurizer for bulk steelmaking.

Example 3

49wt% calcium oxide was mixed with 51wt% aluminum oxide and heated to 1400°C to make the calcium oxide and the aluminum oxide in a molten state, then cooled to room temperature to form 45 grams containing heptaaluminum A calcium aluminate component of dodecacalcium acid, and then, the calcium aluminate component is subjected to a crushing treatment to form a powdered calcium aluminate component with a particle size of 0.3 mm to 1 mm.

The powdered calcium aluminate component, 35 grams of refining slag (source: refining slag of Taiwan electric arc furnace steel plant; with dicalcium silicate crystal phase; components: 0.6wt% sulfur, 57.4wt% calcium oxide CaO , 23.9 wt% SiO ₂ , 5.8 wt % MgO, 4.0 wt % A1 ₂ O ₃ , and 8.3 wt % CaF ₂ ), 2 grams of calcium oxide, 4 grams of calcium fluoride, 2 grams of magnesium oxide , and 4.4 grams of calcium hydroxide are mixed to form a desulfurizing agent for steelmaking, then, the desulfurizing agent for steelmaking is placed in a press (brand: Xinji Machinery Co., Ltd.; model: 02OPM -1001) in a mold for pressing treatment to form a rough preform of the desulfurizer for bulk steelmaking, wherein the pressing treatment pressure is 2t/cm ² to 3t/cm ² , and the time is 90 seconds.

The crude desulfurizer for bulk steelmaking was put into an oven set at a temperature of 110°C to 120°C for 30 minutes of drying to obtain 91.5 g of desulfurizer for bulk steelmaking.

Evaluation item

Phase analysis: 3 grams to 5 grams of desulfurizers for steelmaking in Examples 1 to 3 were placed in an X-ray diffractometer (brand: Brukers; model: D8 Advance ECO X; parameter conditions: accelerating voltage of 40kV , the power is 1000W, and the measurement angle is 20 degrees to 80 degrees), and the results are shown in Figure 1 to Figure 3.

Desulfurization rate (unit: %) measurement: 30 grams of the desulfurizing agents for steelmaking of Examples 1 to 3 were placed in a refining furnace containing 1000 grams of molten steel (containing 0.0307 wt% of sulfur), and Oxygen in the refining furnace was removed, and then, desulfurization treatment was performed, and a carbon-sulfur analyzer (brand: HORIBA; model: EMIA-920V2) was used to measure the content of the molten steel at 10 minutes, 15 minutes and 20 minutes. The content of sulfur (unit: wt %), wherein the temperature of the desulfurization treatment is 1600° C., and the partial pressure of oxygen is less than 20 ppm. The desulfurization rate=[(0.0307－sulfur content at different times)/0.0307]×100%.

Table 1 Element Example 1 Example 2 Example 3 Desulfurizer for steelmaking CaO (wt%) 48.9 50.77 50.3 SiO ₂ (wt%) 8.08 8.02 9.5 MgO (wt%) 5.24 4.93 4.6 Al ₂ O ₃ (wt%) 27.41 27.27 27.7 CaF (wt%) 10.37 9.01 7.9 Desulfurization rate (%) 10 minutes 76.9 79.8 76.5 15 minutes 78.8 81.4 80.8 20 minutes 80.7 82.7 83.4 Content of each component (wt%): [content of each component/(total sum of calcium oxide, silicon dioxide, magnesium oxide, aluminum oxide, calcium fluoride)]×100%.

From the experimental data in Table 1, it can be seen that the desulfurization agent for steelmaking of the present invention can achieve a desulfurization rate of 80.7% to 83.4% after desulfurizing the molten steel for 20 minutes, which indicates that the desulfurization agent for steelmaking of the present invention The preparation method of the agent can indeed prepare a desulfurizing agent for steelmaking with a high desulfurization rate.

1 to 3 , the phase composition of the molten steel containing sulfur after the desulfurization agent for steelmaking of the present invention is subjected to desulfurization treatment includes a component whose composition is Ca ₁₂ Al ₁₄ F ₂ O ₃₂ , and a composition whose composition is Ca The composition and composition of _{5 Al6} O ₁₄ are the composition of Ca ₃ SiO ₅ , but do not contain dicalcium silicate, therefore, the preparation method of the desulfurizing agent for steelmaking of the present invention can indeed select the refining slag containing dicalcium silicate, As a result, the refining slag containing dicalcium silicate can be recycled and reused.

To sum up, by mixing the calcium aluminate component, calcium oxide, magnesium oxide and calcium fluoride with the refining slag, the preparation method of the desulfurizer for steelmaking of the present invention enables the refining slag to be recycled and reused, and at the same time, It is also possible to prepare a desulfurizing agent for steelmaking with a desulfurization rate of 80% or more, so that the object of the present invention can be surely achieved.

However, the above are only examples of the present invention, and should not limit the scope of implementation of the present invention. Any simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the contents of the patent specification are still included in the scope of the present invention. within the scope of the invention patent.

Other features and effects of the present invention will be clearly presented in the embodiments with reference to the drawings, wherein: 1 is an X-ray diffraction spectrum diagram illustrating the phase of the desulfurizing agent for steelmaking obtained in Example 1 of the method for preparing a desulfurizing agent for steelmaking according to the present invention after desulfurizing molten steel containing sulfur composition; 2 is an X-ray diffraction spectrum diagram illustrating the phase of the desulfurizing agent for steelmaking obtained in Example 2 of the method for preparing the desulfurizing agent for steelmaking according to the present invention after desulfurizing the molten steel containing sulfur composition; and 3 is an X-ray diffraction spectrum diagram illustrating the phase of the molten steel containing sulfur obtained by the desulfurizing agent for steelmaking obtained in Example 3 of the method for preparing the desulfurizing agent for steelmaking of the present invention. composition.

none.

Claims (10)

A preparation method of a desulfurizer for steelmaking, comprising the following steps: Step (a), mixing calcium oxide and aluminum oxide, and sequentially performing melting treatment and cooling treatment to form a calcium aluminate component comprising dodecacalcium heptaaluminate; and In step (b), the calcium aluminate component, refining slag, calcium oxide, magnesium oxide and calcium fluoride are mixed and processed to form a composition comprising dodecacalcium heptaaluminate, calcium oxide, silicon dioxide, aluminum oxide, Desulfurizing agent for steelmaking of magnesium oxide and calcium fluoride, and based on the total amount of the desulfurizing agent for steelmaking being 100wt%, the total content of the calcium oxide is in the range of 45wt% to 60wt%, the amount of the silicon dioxide The total content range is 5wt% to 15wt%, the total content range of the aluminum oxide is 15wt% to 30wt%, the total content range of the magnesium oxide is 0wt% to 10wt%, and the total content range of the calcium fluoride is 5wt% to 15wt%. The method for preparing a desulfurizing agent for steelmaking according to claim 1, wherein, in step (a), based on the total amount of the calcium oxide and the aluminum oxide being 100 wt %, the content of the calcium oxide is in the range of 40wt% to 60wt%. The method for producing a desulfurizing agent for steelmaking according to claim 1, wherein, in step (a), the temperature range of the melting treatment is 1400°C or higher. The method for preparing a desulfurizing agent for steelmaking according to claim 1, further comprising, in step (a), performing a crushing treatment after the cooling treatment. The method for preparing a desulfurizing agent for steelmaking according to claim 1, wherein based on the total amount of the desulfurizing agent for steelmaking being 100wt%, the content of the refining slag ranges from 30wt% to 50wt%. The method for preparing a desulfurizing agent for steelmaking according to claim 1, further comprising performing a rolling treatment in sequence after the mixing treatment in step (b). The method for preparing a desulfurizing agent for steelmaking according to claim 6, wherein the pressure range of the pressing treatment is 2t/cm ² to 3t/cm ² . The method for preparing a desulfurizing agent for steelmaking according to claim 7, wherein the time of the pressing treatment is 90 seconds. The method for preparing a desulfurizing agent for steelmaking according to claim 6, further comprising, in the step (b), adding an adhesive to perform the mixing treatment. The method for preparing a desulfurizing agent for steelmaking as claimed in claim 9, wherein, based on the total amount of the desulfurizing agent for steelmaking being 100wt%, the content of the adhesive is 1wt% to 5wt%.

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