Molten iron desulfurizing agent, preparation method thereof and desulfurization method using molten iron desulfurizing agent

Abstract

The invention discloses a molten iron desulfurizing agent, a preparation method thereof and a desulfurization method using the molten iron desulfurizing agent. The molten iron desulfurizing agent contains the following ingredients in percentage by weight: 55 to 70 percent of CaO, 5 to 20 percent of Al2O3, 2 to 4 percent of SiO2, 2 to 15 percent of MgO and 2 to 10 percent of CaF2. According to the invention, the molten iron desulfurizing agent is sprayed onto molten iron for desulfurizing, N2 is used as a powder-carrying gas, and the desulphurizing slag is melted based on the dynamic conditions of the gas and the physical heat of the molten iron, thus the desulfurization purpose is achieved; and after the desulfurization and slagging off treatment, the sulfur content of the molten iron can be reduced to below 0.006%.

Description

technical field

[0001] The invention relates to a desulfurizing agent, in particular to a molten iron desulfurizing agent and a desulfurizing method using the desulfurizing agent. Background technique

[0002] Hot metal pretreatment technology means that in the process of using hot metal as raw material for steelmaking, the hot metal is pre-desulfurized, dephosphorized, desiliconized, etc., to remove harmful elements such as sulfur, phosphorus and alloying element silicon in the hot metal, and to improve the quality of the molten iron. To achieve the purpose of improving the production rhythm of steelmaking, the cleanliness of molten steel and realizing smelting with less slag. Among the hot metal pretreatment technologies, the desulfurization pretreatment method outside the furnace is the most common. Because the pretreatment desulfurization in the molten iron tank is cheaper and more effective than the desulfurization in the steelmaking furnace or refining furnace, so the...

Examples

preparation example Construction

[0017] The preparation and desulfurization method of this hot metal desulfurizer:

[0018] 1. The preparation of hot metal desulfurizer: will contain CaO, Al 2 o 3 , SiO 2 , MgO and CaF 2 The raw materials are melted, and the calcium aluminate slag system is formed according to the specified ratio, pre-melted (melted and mixed uniformly), cooled and crushed, and ground into powder with a particle size between 0.5 and 2 mm to obtain this desulfurizer;

[0019] 2. Canning: Send the mixed desulfurizer into the blowing tank through the conveying device, and use N 2 as a carrier gas.

[0020] 3. Injection: Use the electrical control system to switch the switch circuit, with N 2 As a powder-carrying gas, the desulfurizer is delivered from the injection tank to the spray gun, and sprayed into the molten iron through the spray gun. The injection flow rate adjustment range is 10-50kg / min, the injection pressure is 0.5-1Mpa, and the molten iron temperature range is 1250°C. ~1350°C...

Embodiment 1

[0023] Main components of this hot metal desulfurizer (weight percent): CaO: 64.29%, Al 2 o 3 : 15.98%, SiO 2 : 2.8%, MgO: 2.02%, CaF 2 : 3.8%; melting point 1310°C, particle size 0.5-2mm, molten iron weight 108t, ladle clearance > 600mm, molten iron temperature 1320°C, injection intensity 25kg / min, injection time 12.5min, slag removal time 14min, slag removal rate 95 %; chemical composition of molten iron (percentage by weight): 3.9% C, 0.45% Si, 0.15% Mn, 0.07% P, 0.039% S, and the balance is iron; the sulfur content of molten iron after treatment is 0.006%.

Embodiment 2

[0025] Main components of this hot metal desulfurizer (weight percent): CaO: 63.09%, Al 2 o 3 : 16.78%, SiO 2 : 2.9%, MgO: 3.42%, CaF 2 : 4.2%; melting point 1294°C, particle size 0.5-2mm, molten iron weight 100t, ladle clearance > 600mm, molten iron temperature 1310°C, injection intensity 27kg / min, injection time 10min, slag removal time 12min, slag removal rate 96% Chemical composition of molten iron (percentage by weight): 4.2% C, 0.53% Si, 0.12% Mn, 0.06% P, 0.042% S, and the balance is iron; the sulfur content of the treated molten iron is 0.005%.

technical field

[0001] The invention relates to a desulfurizing agent, in particular to a molten iron desulfurizing agent and a desulfurizing method using the desulfurizing agent. Background technique

[0002] Hot metal pretreatment technology means that in the process of using hot metal as raw material for steelmaking, the hot metal is pre-desulfurized, dephosphorized, desiliconized, etc., to remove harmful elements such as sulfur, phosphorus and alloying element silicon in the hot metal, and to improve the quality of the molten iron. To achieve the purpose of improving the production rhythm of steelmaking, the cleanliness of molten steel and realizing smelting with less slag. Among the hot metal pretreatment technologies, the desulfurization pretreatment method outside the furnace is the most common. Because the pretreatment desulfurization in the molten iron tank is cheaper and more effective than the desulfurization in the steelmaking furnace or refining furnace, so the...

Examples

preparation example Construction

[0017] The preparation and desulfurization method of this hot metal desulfurizer:

[0018] 1. The preparation of hot metal desulfurizer: will contain CaO, Al 2 o 3 , SiO 2 , MgO and CaF 2 The raw materials are melted, and the calcium aluminate slag system is formed according to the specified ratio, pre-melted (melted and mixed uniformly), cooled and crushed, and ground into powder with a particle size between 0.5 and 2 mm to obtain this desulfurizer;

[0019] 2. Canning: Send the mixed desulfurizer into the blowing tank through the conveying device, and use N 2 as a carrier gas.

[0020] 3. Injection: Use the electrical control system to switch the switch circuit, with N 2 As a powder-carrying gas, the desulfurizer is delivered from the injection tank to the spray gun, and sprayed into the molten iron through the spray gun. The injection flow rate adjustment range is 10-50kg / min, the injection pressure is 0.5-1Mpa, and the molten iron temperature range is 1250°C. ~1350°C...

Embodiment 1

[0023] Main components of this hot metal desulfurizer (weight percent): CaO: 64.29%, Al 2 o 3 : 15.98%, SiO 2 : 2.8%, MgO: 2.02%, CaF 2 : 3.8%; melting point 1310°C, particle size 0.5-2mm, molten iron weight 108t, ladle clearance > 600mm, molten iron temperature 1320°C, injection intensity 25kg / min, injection time 12.5min, slag removal time 14min, slag removal rate 95 %; chemical composition of molten iron (percentage by weight): 3.9% C, 0.45% Si, 0.15% Mn, 0.07% P, 0.039% S, and the balance is iron; the sulfur content of molten iron after treatment is 0.006%.

Embodiment 2

[0025] Main components of this hot metal desulfurizer (weight percent): CaO: 63.09%, Al 2 o 3 : 16.78%, SiO 2 : 2.9%, MgO: 3.42%, CaF 2 : 4.2%; melting point 1294°C, particle size 0.5-2mm, molten iron weight 100t, ladle clearance > 600mm, molten iron temperature 1310°C, injection intensity 27kg / min, injection time 10min, slag removal time 12min, slag removal rate 96% Chemical composition of molten iron (percentage by weight): 4.2% C, 0.53% Si, 0.12% Mn, 0.06% P, 0.042% S, and the balance is iron; the sulfur content of the treated molten iron is 0.005%.