阅读说明：本技术 一种含铁尘泥回收利用方法 (Iron-containing dust and mud recycling method ) 是由 田文杰 郭秀键 罗宝龙 雍海泉 赵忠宇 程奇伯 于 2021-08-19 设计创作，主要内容包括：本发明涉及一种含铁尘泥回收利用方法,属于冶金领域。该回收利用方法通过还原焙烧炉将原料高温焙烧成金属化物料,然后将高温的金属化物料直接热压使其变成致密型块,减小比表面积,再将热压的型块熔入铁水,利用铁水的高温熔化金属铁,利用铁水中的残炭还原剩余的氧化铁,杂质随高炉渣除去。该方法无需进入高炉重新冶炼,即可达到回收铁素的目的。本发明有效地提高了还原焙烧料的利用率,最终以较短的处理流程,彻底解决了其回收利用的问题。(The invention relates to a method for recycling iron-containing dust and mud, and belongs to the field of metallurgy. The recycling method comprises the steps of roasting raw materials into a metalized material at a high temperature through a reduction roasting furnace, then directly hot-pressing the high-temperature metalized material to form a compact block, reducing the specific surface area, melting the hot-pressed block into molten iron, melting the metallic iron by utilizing the high temperature of the molten iron, reducing the residual iron oxide by utilizing the carbon residue in the molten iron, and removing impurities along with blast furnace slag. The method can achieve the aim of recovering the ferrite without entering a blast furnace for smelting again. The invention effectively improves the utilization rate of the reduction roasting material, and finally solves the problem of recycling the reduction roasting material by a shorter treatment process.)

1. The method for recycling the iron-containing dust and mud is characterized by sequentially comprising the following steps of:

s1, carrying out carbon blending, mixing and cold forming on the iron-containing dust mud, and then reducing the iron-containing dust mud through a reduction roasting furnace to produce high-temperature metallized materials;

s2, directly pressing the metal material at the discharging temperature into a compact block by adopting a hot press molding mode to reduce the specific surface area of the compact block;

and S3, directly adding the hot-pressed briquette into a blast furnace molten iron runner or a molten iron tank, melting the briquette by using high-temperature molten iron so that the metallic iron in the briquette is immersed into the molten iron, and reducing the iron oxide in the briquette into the metallic iron by using carbon in the molten iron and then putting the metallic iron into the molten iron.

2. The recycling method of iron-containing dust and sludge according to claim 1, characterized in that: in step S1, the iron-containing dust is one or more of converter dry ash, OG mud, electric furnace ash, and blast furnace gas ash/mud generated in the steel smelting process.

3. The recycling method of iron-containing dust and sludge according to claim 1, characterized in that: in step S1, the iron-containing sludge is carbon-blended according to a C/O ratio of 1.0 to 1.1.

4. The recycling method of iron-containing dust and sludge according to claim 1, characterized in that: in step S1, the reduction roasting furnace is a rotary hearth furnace, the reduction temperature is 1100-1300 ℃, the discharge temperature of the produced metalized materials is 1000-1100 ℃, and the granularity is not more than 50 mm.

5. The iron-containing dust and sludge recycling method according to claim 1 or 4, wherein: in step S2, feeding the material into a forming machine for hot press forming at the discharging temperature; the weight of the single block of the briquette is not less than 500g, and the density is not less than 4.5t/m³Specific surface area of 50cm²/kg～350cm²/kg。

6. The recycling method of iron-containing dust and sludge according to claim 1, characterized in that: in step S2, the temperature of the hot-pressed briquette is 400 to 500 ℃.

7. The recycling method of iron-containing dust and sludge according to claim 1, characterized in that: in step S3, 20kg to 50kg of shaped blocks are added to each ton of molten iron in the blast furnace molten iron runner or the molten iron tank.

Technical Field

The invention belongs to the field of metallurgy, and particularly relates to a method for recycling iron-containing dust and mud.

Background

The density of the metallized material generated in the process of treating the iron-containing dust and mud by adopting the rotary hearth furnace for reduction roasting is lower and is only 1.4-1.8 t/m³And 20-25% of powdery material, so that the whole amount of the powder material cannot be utilized in ironmaking. Meanwhile, the metalized material is low in density, large in pores and easy to oxidize, so that the metalized material is difficult to melt quickly due to low density and slow heat transfer when being added into molten iron, a large amount of the metalized material floats on the surface layer in the form of slag and is discharged along with the slag, and resource waste is caused.

Disclosure of Invention

In view of the above, the present invention aims to provide a method for recycling iron-containing materials, so as to solve the problem that the metallic materials generated in the process of treating iron-containing dust and sludge by using a rotary hearth furnace for reduction roasting are difficult to use.

In order to achieve the purpose, the invention provides the following technical scheme:

a method for recycling iron-containing dust comprises the following steps in sequence:

s1, carrying out carbon blending, mixing and cold forming on the iron-containing dust mud, and then reducing the iron-containing dust mud through a reduction roasting furnace to produce high-temperature metallized materials;

s2, directly pressing the metal material at the discharging temperature into a compact block by adopting a hot press molding mode to reduce the specific surface area of the compact block;

and S3, directly adding the hot-pressed briquette into a blast furnace molten iron runner or a molten iron tank, melting the briquette by using high-temperature molten iron so that the metallic iron in the briquette is immersed into the molten iron, and reducing the iron oxide in the briquette into the metallic iron by using carbon in the molten iron and then putting the metallic iron into the molten iron.

Further, in step S1, the iron-containing dust is one or more of converter dry ash, OG mud, electric furnace ash, and blast furnace gas ash/mud generated in the steel smelting process.

Further, in step S1, the iron-containing sludge is carbon-blended according to a C/O ratio of 1.0 to 1.1.

Further, in step S1, the reduction roasting furnace is a rotary hearth furnace, the reduction temperature is 1100-1300 ℃, the discharge temperature of the produced metalized material is 1000-1100 ℃, and the granularity is not more than 50 mm.

Further, in step S2, feeding the material into a forming machine for hot press forming at the discharging temperature; the weight of the single block of the briquette is not less than 500g, and the density is not less than 4.5t/m³Specific surface area of 50cm²/kg～350cm²/kg。

Further, in step S2, the temperature of the hot-pressed briquette is 400 to 500 ℃.

Further, in step S3, 20kg to 50kg of briquette is added to each ton of molten iron in the blast furnace molten iron runner or the molten iron tank.

The invention has the beneficial effects that:

and carrying out reduction roasting on the iron-containing dust and mud through a reduction roasting furnace so that the iron-containing dust and mud is converted into a highly metallized material. Under the high temperature of discharging, a plurality of small balls are hot-pressed into compact blocks, so that the specific surface area is greatly reduced, the surface oxidation condition in the conveying and storing processes is reduced, and the sufficient metallization rate is kept. The smaller specific surface area can also reduce heat dissipation and heat loss, and maintain the temperature of the material, thereby improving the heat conductivity coefficient of the material. So that it can be added to the hot molten iron as much as possible. On the premise of ensuring that the density and the size of the block have better matching, the melting of the hot-pressing block can be ensured to be completed in reasonable time.

The hot-pressed shaped block is directly added into molten iron discharged from a blast furnace (namely, in a molten iron ditch or a molten iron tank), metal iron in the shaped block is melted by utilizing the high temperature of the molten iron, meanwhile, residual carbon in the molten iron is utilized to reduce the residual iron oxide in the shaped block, and impurities are removed along with blast furnace slag. The method not only solves the problems of oxidation of the materials and low melting speed of the materials in molten iron in the processes of conveying and storing (caused by small density and many pores of the metallized materials), but also hot-presses 20 to 25 percent of the powdery metal materials obtained by reduction roasting and the pellets into usable compact blocks, effectively improves the utilization rate of the reduction roasting materials, and finally thoroughly solves the problem of recycling by a short treatment process.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the means of the instrumentalities and combinations particularly pointed out hereinafter.

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.

A method for recycling iron-containing dust comprises the following steps in sequence:

s1, carrying out carbon blending, mixing and cold forming on iron-containing dust and mud, such as converter dry-process ash, OG mud, electric furnace ash, blast furnace gas ash/mud and the like generated in the steel smelting process according to the C/O (carbon/oxygen ratio) of 1.0-1.1, and then, feeding the iron-containing dust and mud into a rotary hearth furnace for reduction to generate high-temperature metallized materials; wherein the reduction temperature of the rotary hearth furnace is 1250 ℃, the discharge temperature of the metalized material is 1000-1100 ℃ after reduction roasting, the metalized material is in a high temperature state, and the granularity of the metalized material is 40 mm.

S2, directly pressing the high-temperature (namely the discharge temperature is 1000-1100 ℃) metal material into a molding block by adopting a stamping hot forming mode, wherein the molding block is a single block with the weight of 25kg and the density of 5t/m³60cm in specific surface area²A cylindrical or shaped block of 500g weight and 5t/m density³340cm of specific surface area²A polygon of/kg. The temperature of the compact block after hot press molding is 400-500 ℃.

And S3, when the blast furnace normally taps, uniformly adding the hot-pressing blocks into the blast furnace molten iron ditch according to the proportion that 30kg (hot-pressing) blocks are added into each ton of molten iron, melting the metallic iron by utilizing the temperature of the molten iron, and reducing the ferric oxide by utilizing the carbon in the molten iron, thereby realizing the recovery of the metallic elements. Specifically, in the process of iron discharge of the blast furnace, the shaped block is added into a blast furnace molten iron groove, so that the shaped block is immersed in the molten iron and flows and is melted at the same time, and slag and iron separation is realized.

The principle of the recycling method is as follows:

the iron-containing dust and mud are subjected to reduction roasting through a reduction rotary hearth furnace, so that the iron-containing dust and mud are converted into a highly metallized material, at the moment, iron in the metallized material mainly exists in a metallic iron form, the specific surface area of the material can be reduced through a hot press molding process, the oxidation condition of the surface in the conveying and storing processes is relieved, and the sufficiently high metallization rate is kept. The smaller specific surface area can also reduce heat dissipation and heat loss, and maintain the temperature of the material, thereby improving the heat conductivity coefficient of the material. The method can utilize 20 to 25 percent of powdery metal material generated after reduction roasting together by hot pressing. The compact block after hot pressing is immersed in molten iron, the molten iron is melted by utilizing the temperature of the molten iron, iron oxide is reduced by utilizing carbon residue in the molten iron, and slag is removed along with blast furnace slag, so that the slag-iron separation can be realized without entering a blast furnace for re-smelting the metallized material, and iron resources are effectively recovered.

Taking a reduction rotary hearth furnace of a certain steel mill as an example, 25 million t/a of iron-containing dust and mud are treated to produce 16 million t/a of hot-pressed blocks, the specification of the hot-pressed blocks is cylindrical phi 200 multiplied by 150, the pressure of a stamping head is 150MPa, and the bulk density of the hot-pressed blocks is 5t/m³The monolith weighed 23 kg.

Adding 12t of hot-pressing block according to 300t of tapping of blast furnace, and if the total iron content in the hot-pressing block is 70%, and 90% enters molten iron after melting, recovering 12 x 70% x 90% of metallic iron once, namely 7.56 t.

The recycling method firstly converts the metalized materials into compact blocks, solves the problems of easy oxidation and slow melting process speed caused by porosity of the metalized materials, and also hot presses about 20 to 25 percent of metal powder in the metalized materials and the pellets together, thereby improving the product utilization rate; the metallic iron of the hot-pressing block is melted by utilizing the temperature of the molten iron, the iron oxide is reduced by utilizing the carbon residue of the molten iron, the separation of slag and iron is realized, the purpose of recovering the ferrite can be achieved without entering a blast furnace for re-smelting, and the problem of recycling is thoroughly solved.

Finally, the above embodiments are only intended to illustrate the technical solutions of the present invention and not to limit the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions, and all of them should be covered by the claims of the present invention.