CN112226571A

CN112226571A - Method for preparing converter slagging agent by recovering refining slag

Info

Publication number: CN112226571A
Application number: CN202011037636.5A
Authority: CN
Inventors: 彭犇; 吴龙; 岳昌盛; 张国华; 王红阳; 侯勇
Original assignee: University of Science and Technology Beijing USTB; Central Research Institute of Building and Construction Co Ltd MCC Group
Current assignee: University of Science and Technology Beijing USTB; Central Research Institute of Building and Construction Co Ltd MCC Group
Priority date: 2020-09-28
Filing date: 2020-09-28
Publication date: 2021-01-15

Abstract

The invention relates to a method for recycling and preparing a converter slag melting agent from refining slag, which comprises the steps of mixing 64-74% of refining slag tailings, 5-15% of iron scale, 10% of lime, 6% of a binder (3% of bentonite and 3% of water glass), and 5% of water, briquetting, drying and the like to prepare the converter slag melting agent. The prepared slag melting agent has the advantages of high strength, high alkalinity, high dephosphorization rate and the like. The invention is beneficial to opening up a new way for recycling the refining slag, reduces the consumption of the converter slag making materials and the environmental pollution caused by the discharge of the refining slag, and has good application prospect.

Description

Method for preparing converter slagging agent by recovering refining slag

Technical Field

The invention relates to the technical field of ferrous metallurgy, in particular to a method for preparing a converter steelmaking slag melting agent by recovering refining tailings.

Background

With the increasing of steel output in China, in recent years, the amount of refined waste slag generated in China is over 1000 million tons each year. At present, the comprehensive utilization rate of refining slag in China is low, most domestic enterprises can only accumulate in a slag yard for treatment, and the problems of serious environmental pollution and resource waste are caused.

The refining slag recycling mainly comprises two methods of cold state recycling and hot state recycling. The refining slag hot state recovery means that molten slag is poured into a refining furnace again to participate in refining, and the recovery method can reduce the consumption of new slag and recover part of heat energy of hot slag and metal carried in the slag. However, the enrichment of the impurity element sulfur in the slag can cause the occurrence of resulfurization, so that the recycling times of the refining slag are limited to a certain extent. For this reason, patent CN104109737A proposes a desulfurization means by blowing air/oxygen to the hot refining slag, which solves the problem of sulfur enrichment in slag. However, the desulfurization process is a process of oxidizing sulfide in the slag, and may result in harmful gas SO₂The need to maintain the desulfurization process above 1300 c, presents energy consumption problems that hinder the application of this process. The cold recovery method is generally a method of obtaining metallurgical lumps through screening, re-batching and agglomeration of tailings, and then re-adding the lumps into a refining furnace for use. Compared with the hot state recovery, the cold state recovery can adjust the components of the slag by additionally adding solvents such as lime and the like, so that the enrichment effect of sulfur is weakened, and the resulfurization phenomenon is generally not caused. In addition, cold recycling also has certain advantages in treating tailings that have already been deposited.

After the refining slag is repeatedly used for desulfurization refining, the problem of sulfur enrichment is inevitably caused. Compared with the recycling of the refining slag for the converter slagging agent, the recycling of the refining slag for the converter slagging agent has higher potential. Since most of the refining slag belongs to reducing slag, the phosphorus content of the tailings of the refining slag is usually very low, so that the tailings still have good dephosphorization capability. The refining slag has the advantages of low melting point, high slag melting speed, high alkalinity and the like, which are required by the converter slag melting agent. The main difference between the refining slag and the converter slag is that the latter is an oxidizing slag, and the iron oxide content of the former is usually less than 1%, so that the waste refining slag needs to be modified by adding iron oxide. The iron oxide can accelerate the slagging speed and the dephosphorization and decarburization efficiency in the early stage of smelting.

Disclosure of Invention

The invention aims to provide a refining slag recycling method to achieve the purpose of resource recycling in view of the problems of low comprehensive utilization rate of refining slag and serious environmental pollution and resource waste caused by the accumulation treatment of the refining slag.

In order to solve the technical problems, the invention adopts the following technical scheme:

(1) the method is characterized in that refining slag tailings, lime and iron scales are used as raw materials, a small amount of water is added after a binder is added, the mixture is uniformly mixed, and then the mixture is pressed into blocks.

(2) And (2) drying the blocks in the step (1), wherein the dried blocks are used as a steelmaking slag melting agent, and recycling of refining slag is realized.

The refining slag tailings in the step (1) are CaO-MgO-Al₂O₃-SiO₂-CaF₂The LF refining slag tailings contain, by mass, 45-50% CaO, 5-8% MgO, and Al₂O₃＝20～30％，SiO₂＝10～15％，CaF₂＝5～10％。

The iron scale in the step (1) is black flaky iron-containing oxide generated in a steel rolling process, and the TFe is about 57-60%.

The binder in the step (1) is bentonite and water glass composite binder. Bentonite: SiO 2₂＝55～57％，Al₂O₃16-19%; water glass: SiO 2₂Not less than 29 percent and the modulus is 3.1-3.4.

The mixture ratio of the materials in the step (1) is as follows: 64-74% of refining slag tailings, 5-15% of iron scale, 10% of lime, 6% of binder (3% of bentonite and 3% of water glass) and 5% of water.

And (2) in the uniformly mixing process in the step (1), firstly, uniformly mixing the refining slag tailings and the iron scale, then adding the binder and the lime, uniformly mixing, finally adding a small amount of water, stirring and uniformly mixing.

The pressure of the briquetting in the step (2) is 100-300 Mpa.

And (3) drying at the temperature of 110 ℃ for 1h in the step (2).

The invention recycles the refining slag tailings and obtains good effect. The refining slag is reused as a converter slagging agent after a series of treatments such as modification, agglomeration and the like. The prepared slag melting agent has the advantages of high strength, high alkalinity, high dephosphorization rate and the like. The method not only can reduce the consumption of the traditional slag melting agent and reduce the steel-making cost, but also solves the problem of the accumulation of the refining slag tailings, can create good economic and environmental benefits, and opens up a new way for recycling the refining slag. Is expected to reduce the consumption of the slag making materials of the converter and the environmental pollution caused by the emission of the refining slag, and has good application prospect.

Detailed Description

Example 1

According to the mass fraction, 74 percent of refining slag tailings, 10 percent of lime, 5 percent of iron scale, 3 percent of bentonite, 3 percent of water glass and 5 percent of water are weighed. Firstly, mixing the refining slag tailings and iron scale, then adding a binder and lime for mixing, and finally adding water for stirring and uniformly mixing.

The mixture was pressed under a pressure of 100MPa into a cylinder of about 30mm diameter and about 50mm height.

And putting the material block into a constant-temperature oven, and preserving heat for 1h at 110 ℃.

The main physical and chemical indexes of the dried block are as follows: the strength is higher than 800N/cm²Water content of about 3%; the alkalinity is more than or equal to 3.2; when the slag melting agent is used for dephosphorization experiments, the dephosphorization rate of molten steel is more than 90%.

Example 2

According to the mass fraction, 64% of refining slag tailings, 10% of lime, 15% of iron scale, 3% of bentonite, 3% of water glass and 5% of water are weighed. Firstly, mixing the refining slag tailings and iron scale, then adding a binder and lime for mixing, and finally adding water for stirring and uniformly mixing.

The mixture was pressed under a pressure of 300MPa into a cylinder of about 30mm diameter and about 50mm height.

The block was placed in a thermostat and incubated at 110 ℃ for 1 h.

The main physical and chemical indexes of the dried block are as follows: the strength is higher than 800N/cm²Water content about 3%; the alkalinity is more than or equal to 3.2; when the slag melting agent is used for dephosphorization experiments, the dephosphorization rate of molten steel is more than 90%.

Claims

1. A method for preparing a converter slagging agent by recovering refined slag is characterized by comprising the following steps: the method comprises the following steps:

(1) taking refining slag tailings, lime and iron scale as raw materials, adding a binder, adding a small amount of water, uniformly mixing, and then briquetting;

2. The method of claim 1, wherein: the refining slag tailings in the step (1) are CaO-MgO-Al₂O₃-SiO₂-CaF₂The LF refining slag tailings comprise the following chemical components: 45-50% CaO, 5-8% MgO, and Al₂O₃＝20～30％，SiO₂＝10～15％，CaF₂＝5～10％。

3. The method of claim 1, wherein: the iron scale in the step (1) is black flaky iron-containing oxide generated in a steel rolling process, and the TFe is 57-60%.

4. The method of claim 1, wherein: the binder in the step (1) is a bentonite and water glass composite binder; bentonite: SiO 2₂＝55～57％，Al₂O₃16-19%; water glass: SiO 2₂Not less than 29 percent and the modulus is 3.1-3.4.

5. The method of claim 1, wherein: the mixture ratio of the materials in the step (1) is as follows: 64-74% of refining slag tailings, 5-15% of iron scale, 10% of lime, 6% of binder (3% of bentonite and 3% of water glass) and 5% of water.

6. The method of claim 1, wherein: in the uniformly mixing process in the step (1), firstly, the refining slag tailings and the iron scale are mixed, then, the binder and the lime are added for mixing, and finally, a small amount of water is added for stirring and uniformly mixing.

7. The method of claim 1, wherein: the pressure of the briquetting in the step (2) is 100-300 Mpa.

8. The method of claim 1, wherein: and (3) drying at the temperature of 110 ℃ for 1h in the step (2).