Fluorine-free KR desulfurizer and preparation method thereof

Abstract

The invention relates to a fluoride-free KR desulfurizing agent and a preparation method thereof, and the fluoride-free KR desulfurizing agent comprises the following components in percentage by weight: 87-95% of lime; 3-6% of borax; 4-8% of pre-melted slag; the balance is impurities; under the condition of rapid desulfurization, the borax and the pre-melted slag are used for replacing fluorite, the fluxing effect is achieved, meanwhile, the problem that a ladle refractory and a KR stirring head are prone to being eroded by using the fluorite is solved, the service life of the ladle and the service life of the KR stirring head are prolonged, and the steelmaking cost is saved. And meanwhile, no fluorite is used, so that the pollution to the environment in the metallurgical process is also reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of iron and steel metallurgy, and particularly relates to a fluorine-free KR desulfurizer and a preparation method thereof. Background Art

[0002] KR desulfurization can significantly reduce the sulfur content in molten steel and effectively improve the quality and performance of steel. By removing sulfur, the toughness and ductility of steel are enhanced, enabling it to better adapt to various complex use environments and processing technologies, and improving the reliability and safety of steel. The KR desulfurization process has the characteristics of high desulfurization efficiency and stability. It can achieve the ideal desulfurization effect in a relatively short period of time, and the operation process is relatively stable, easy to control and manage, which helps to improve the overall efficiency and stability of steel production. KR desulfurization also helps to reduce production costs. Compared with some other desulfurization methods, KR desulfurization has certain advantages in equipment investment and operating costs, and can also reduce the cost and resource consumption of subsequent processing links.

[0003] However, in the KR desulfurization process, the most commonly used desulfurizer is a desulfurizer composed of lime and fluorite, in which lime is used for desulfurization and fluorite mainly plays a role in fluxing. However, the large-scale use of fluorite will corrode the lining of the ladle and the KR stirring head, shortening their service life; and the fluorine in fluorite will also pollute the environment, so it is not suitable for large-scale use. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention provides a fluorine-free KR desulfurizer, comprising the following weight percentages:

[0005] Lime 87-95%; Borax 3-6%;

[0006] Pre-melted slag 4-8%;

[0007] The rest are impurities.

[0008] Furthermore, in the fluorine-free KR desulfurizer of the present invention, the lime is active lime, wherein: CaO>93%, SiO2<1%, S<0.025%.

[0009] Furthermore, in the fluorine-free KR desulfurizer of the present invention, the Na2B4O7·10H2O in the borax is ≥ 95%.

[0010] Furthermore, in the fluorine-free KR desulfurizer of the present invention, the main components of the pre-melted slag are: CaO: 45-52%, Al2O3: 35-40%, MgO: 8-11%, SiO2: 0-3%, T·C: 0-1%; and the rest are impurities.

[0011] Furthermore, in the fluorine-free KR desulfurizer of the present invention, the particle size of the fluorine-free KR desulfurizer is 0 to 3 mm.

[0012] The present invention also provides a method for preparing a fluorine-free KR desulfurizer, comprising the following steps:

[0013] S1: The batching system automatically batches the desulfurizer according to the set formula and transports the raw materials to the mill;

[0014] S2: setting the required particle size of the fluorine-free KR desulfurizer on the grinding mill, and mixing and grinding the raw materials to the required particle size;

[0015] S3: Collect and store the ground materials in silos.

[0016] Furthermore, in the method for producing the fluorine-free KR desulfurizing agent of the present invention, the grinding mill is a Raymond mill or a ball mill.

[0017] The present invention adopts a fluorine-free KR desulfurizer, which has the following weight percentages: 87-95% lime; 3-6% borax; 4-8% pre-melted slag; and the rest are impurities; it can achieve rapid desulfurization. Borax and pre-melted slag are used in the present invention to replace fluorite, which not only plays a fluxing effect, but also solves the problem that fluorite is easy to corrode the refractory material of the ladle and the KR stirring head, prolongs the service life of the ladle and the KR stirring head, and saves steelmaking costs. At the same time, since there is no use of fluorite, the pollution of the metallurgical process to the environment is also reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The manufacturing method flow chart of the present invention. DETAILED DESCRIPTION

[0019] In the first embodiment of the present invention, a fluorine-free KR desulfurization agent is provided, the following weight percentages include:

[0020] Lime 87-95%; borax 3-6%; pre-melted slag 4-8%; the rest are impurities.

[0021] The lime in the fluorine-free KR desulfurizer of the present invention is active lime, wherein: CaO>93%, SiO2<1%, S<0.025%. Na2B4O7·10H2O in borax≥95%. The main components of the pre-melted slag range from: CaO: 45 to 52%, Al2O3: 35 to 40%, MgO: 8 to 11%. SiO2: 0 to 3%, T·C: 0 to 1%; the rest are impurities. The particle size of the fluorine-free KR desulfurizer is 0 to 3 mm.

[0022] In a second embodiment of the present invention, a method for producing a fluorine-free KR desulfurizing agent is provided, comprising the following steps:

[0023] S1: The batching system automatically batches the desulfurizer according to the set formula and transports the raw materials to the mill;

[0024] S2: setting the required particle size of the fluorine-free KR desulfurizer on the grinding mill, and mixing and grinding the raw materials to the required particle size;

[0025] S3: Collect and store the ground materials in silos.

[0026] In the method for producing the fluorine-free KR desulfurizing agent in the second embodiment of the present invention, a Raymond mill or a ball mill is used as the pulverizer.

[0027] In order to better illustrate the above technical effects, three embodiments of the fluorine-free KR desulfurizer of the present invention are listed.

[0028] A KR powder spray desulfurization test was carried out on a 270t KR ladle in a domestic steel plant.

[0029] In the comparative example, a conventional calcium oxide-based desulfurizer was used, and its composition was: CaO: 85.7%, CaF: 8.90%.

[0030] The composition of Example 2 is: CaO: 87.15%, Al2O3: 1.9%, SiO2: 0.62%, MgO: 2.9%, Na2B4O7·10H2O: 4.85%, S: 0.016%. The temperature of the molten iron in the ladle is 1350°C, and the unit consumption of the desulfurizer is 7.3kg / t.

[0031] The composition of Example 3 is: CaO: 86.59%, Al2O3: 1.8%, SiO2: 0.65%, MgO: 2.77%, Na2B4O7·10H2O: 4.9%, S: 0.018%. The temperature of the molten iron in the ladle is 1380°C, and the unit consumption of the desulfurizer is 7.3kg / t.

[0032] Example 4 The components are: CaO: 87.27%, Al2O3: 2%, SiO2: 0.61%, MgO: 2.95%, Na2B4O7·10H2O: 4.85%, S: 0.015%. The temperature of the molten iron in the ladle is 1350°C, and the unit consumption of the desulfurizer is 8.2kg / t.

[0033] The results are as follows:

[0034]

[0035] Based on the above technical effects, in Example 2, Example 3, and Example 4, after adding the fluorine-free KR desulfurizer in this example, the desulfurization rate was increased from 82.5% in the comparative example to 92.7%, 93.6%, and 93.1%, respectively, and the desulfurization efficiency was effectively improved.

Claims

1. A fluorine-free KR desulfurizer, characterized in that: The fluorine-free KR desulfurizer comprises the following weight percentages: Lime 87-95%; Borax 3-6%; Pre-melted slag 4-8%; The rest are impurities.

2. The fluorine-free KR desulfurizing agent according to claim 1, characterized in that: The lime is high-grade active lime, wherein: CaO>93%, SiO2<1%, S<0.025%.

3. The fluorine-free KR desulfurizing agent according to claim 1, characterized in that: The borax Na2B4O7·10H2O≥95%.

4. The fluorine-free KR desulfurizing agent according to claim 1, characterized in that: The main components of the pre-melted slag are: CaO: 45-52%, Al2O3: 35-40%, MgO: 8-11%, SiO2: 0-3%, T·C: 0-1%; and the rest are impurities.

5. The fluorine-free KR desulfurizing agent according to claim 1, characterized in that: The particle size of the fluorine-free KR desulfurizer is 0-3 mm.

6. A method for producing a fluorine-free KR desulfurizing agent, characterized in that: The following steps are involved: S1: The batching system automatically batches the ingredients according to the set desulfurizer formula and transports the raw materials to the mill; S2: setting the required particle size of the fluorine-free KR desulfurizer on the grinding mill, and mixing and grinding the raw materials to the required particle size; S3: Collect and store the ground materials in silos.

7. The method for producing a fluorine-free KR desulfurizing agent according to claim 6, characterized in that: The grinding mill is a Raymond mill or a ball mill.

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