阅读说明：本技术 一种提高铁水脱硫率的方法 (Method for improving desulfurization rate of molten iron ) 是由 王东彦 姜伟忠 王士彬 王波 于 2020-06-28 设计创作，主要内容包括：一种提高铁水脱硫率的方法,在高炉冶炼时,高炉铁水中硫负荷小于3Kg/t(铁水),高炉铁水温度1450～1550℃,炉渣二元碱度R2＝1.2～1.3,炉渣中氧化铝含量在13～22wt％,氧化镁含量不大于20wt％,且,氧化镁和氧化铝的含量之比控制在0.3～0.5。采用本发明所述方法,在二元碱度1.2-1.3范围内,可以获得更好的的炉渣脱硫能力,以此提高铁水质量。(A method for improving the desulfurization rate of molten iron comprises the steps of carrying out blast furnace smelting, wherein the sulfur load of the blast furnace molten iron is less than 3Kg/t (molten iron), the temperature of the blast furnace molten iron is 1450-1550 ℃, the binary basicity R2 of slag is 1.2-1.3, the content of aluminum oxide in the slag is 13-22 wt%, the content of magnesium oxide is not more than 20 wt%, and the content ratio of the magnesium oxide to the aluminum oxide is controlled to be 0.3-0.5. By adopting the method, better slag desulfurization capability can be obtained within the range of 1.2-1.3 of the binary alkalinity, so that the quality of molten iron is improved.)

1. A method for improving the desulfurization rate of molten iron comprises the steps of carrying out blast furnace smelting, wherein the sulfur load of the blast furnace molten iron is less than 3Kg/t (molten iron), the temperature of the blast furnace molten iron is 1450-1550 ℃, the binary basicity R2 of slag is 1.2-1.3, the content of aluminum oxide in the slag is 13-22 wt%, the content of magnesium oxide is not more than 20 wt%, and the content ratio of the magnesium oxide to the aluminum oxide is controlled to be 0.3-0.5.

2. The method according to claim 1, wherein the binary basicity of the slag R2 is 1.2-1.25, and the weight ratio of magnesium oxide to aluminum oxide in the slag is controlled to 0.4-0.5.

3. The method for improving the desulfurization rate of molten iron according to claim 1, wherein the binary basicity R2 of the slag is greater than 1.25 and not greater than 1.3, and the weight ratio of magnesium oxide to aluminum oxide in the slag is controlled as follows: 0.3 or more and less than 0.4.

Technical Field

The invention relates to a blast furnace smelting technology, in particular to a method for improving the desulfurization rate of molten iron.

Background

The current state of the existing blast furnace method for producing molten iron is that the quality of raw fuel is in a descending trend and the load of sulfur entering the furnace is obviously increased in order to reduce the production cost. Therefore, in order to ensure the quality of molten iron, the optimal control of the desulfurization operation in the blast furnace ironmaking process becomes key.

In the prior art, a lot of researches are carried out on blast furnace process desulfurization, and desulfurization influence factors such as furnace temperature, slag alkalinity, slag amount and the like are determined, such as Chinese patent CN201710013294, but in the prior art, no description is given for controlling the desulfurization capacity of the slag by alumina and the furnace temperature. The practical production results show that the content of the alumina in the slag has great influence on the desulfurization capacity and effect of the slag.

In addition, although the prior literature researches the influence of high alumina in the blast furnace slag on desulfurization, the corresponding binary basicity is only below 1.2. The binary basicity of the water R2,for CaO and SiO in slag₂The weight percentages of the two components are divided (CaO/SiO)₂) The value obtained. And the binary alkalinity in actual operation is often over 1.2, so that the research on the optimized slag-blending desulfurization method under the binary alkalinity of 1.2-1.3 has great significance for improving the quality of molten iron.

Disclosure of Invention

The invention aims to provide a method for improving the molten iron desulphurization rate, which can obtain better slag desulphurization capability within the range of 1.2-1.3 of binary alkalinity so as to improve the molten iron quality.

In order to achieve the purpose, the technical scheme of the invention is as follows:

a method for improving the desulfurization rate of molten iron comprises the steps of carrying out blast furnace smelting, wherein the sulfur load of the blast furnace molten iron is less than 3Kg/t (molten iron), the temperature of the blast furnace molten iron is 1450-1550 ℃, the binary basicity R2 of slag is 1.2-1.3, the content of aluminum oxide in the slag is 13-22 wt%, the content of magnesium oxide is not more than 20 wt%, and the content ratio of the magnesium oxide to the aluminum oxide is controlled to be 0.3-0.5.

Preferably, the binary basicity R2 of the slag is 1.2-1.25, and the weight ratio of magnesium oxide to aluminum oxide in the slag is controlled to be 0.4-0.5.

Preferably, the binary basicity R2 of the slag is more than 1.25 and less than or equal to 1.3, and the weight ratio of magnesium oxide to aluminum oxide in the slag is controlled as follows: 0.3 or more and less than 0.4.

In the method for improving the desulfurization rate of molten iron, when the binary basicity of the slag is 1.2-1.25 and the weight ratio of magnesium oxide to aluminum oxide in the slag is controlled to be 0.4-0.5, a better desulfurization effect can be obtained. It is because: the weight ratio of magnesium oxide to aluminum oxide is controlled between 0.4 and 0.5, which is equivalent to the increase of alkalinity. More importantly, at the same time, the viscosity is relatively low, and the desulfurization kinetic conditions are improved.

When the binary basicity of the slag is more than 1.25 and less than or equal to 1.3, the weight ratio of magnesium oxide and aluminum oxide in the slag is controlled as follows: a desulfurization effect can be improved by not less than 0.3 and not more than 0.4. Under such conditions, the basicity is already high, and at this time, the ratio of the weight of magnesium oxide to that of aluminum oxide is controlled to be not less than 0.3 and less than 0.4, so that good slag fluidity can be obtained, and desulfurization is facilitated.

The invention has the beneficial effects that:

by adopting the method, when the binary basicity of the slag is 1.2-1.3, the weight ratio of magnesium oxide to aluminum oxide in the slag is controlled to be 0.3-0.5, and the average desulfurization efficiency is improved by 8.68% compared with the weight ratio of magnesium oxide to aluminum oxide in the slag which is controlled to be 0.2-0.3; compared with the slag in which the weight ratio of magnesium oxide to aluminum oxide is controlled to be 0.5-0.6, the average desulfurization efficiency is improved by 8.76%.

By adopting the method, when the binary basicity of the slag is 1.2-1.25, the weight ratio of magnesium oxide to aluminum oxide in the slag is controlled to be 0.4-0.5, and compared with the weight ratio of magnesium oxide to aluminum oxide in the slag which is controlled to be 0.3-0.4, the average desulfurization efficiency is improved by 4.2%.

By adopting the method, when the binary basicity of the slag is more than 1.25 and less than or equal to 1.3, the weight ratio of magnesium oxide to aluminum oxide in the slag is controlled as follows: more than or equal to 0.3 and less than 0.4, and the average desulfurization efficiency is improved by 4.19 percent compared with the weight ratio of magnesium oxide to aluminum oxide in the slag controlled between 0.4 and 0.5.

Detailed Description

The present invention will be further described with reference to the following examples.

The examples of the present invention refer to table 1, which shows that in the blast furnace smelting, the sulfur load in the blast furnace molten iron, the temperature of the blast furnace molten iron, and the binary basicity R2 of the slag are 1.2 to 1.3, and the ratio of the alumina content, the magnesia-alumina content, and the corresponding average desulfurization efficiency.

TABLE 1