阅读说明：本技术 一种以尿素为脱硫剂的烧结料及烧结方法 (Sintering material using urea as desulfurizer and sintering method ) 是由 赵满祥 刘征建 张建良 王耀祖 张勇 牛乐乐 李思达 郑敬先 潘明铭 于 2021-06-03 设计创作，主要内容包括：本发明提供了一种以尿素为脱硫剂的烧结料及烧结方法,所述烧结料从下到上依次包括铺底料层、第一料层和第二料层,其中,所述第一料层由尿素混合料构成,所述尿素混合料的粒径为3～15mm,所述尿素混合料中,尿素的质量分数为0.01％～0.12％；所述第二料层由烧结混合料构成。采用本发明提供的方法,烧结烟气中SO-2的排放浓度为145.68-172.62mg/m～(3),脱硫率为77.8％～82.5％,烟气脱硫效果好,减排后烟气SO-2排放浓度符合国家排放标准(200mg/m～(3)),对环境友好。(The invention provides a sintering material taking urea as a desulfurizing agent and a sintering method, wherein the sintering material sequentially comprises a base material laying layer, a first material layer and a second material layer from bottom to top, wherein the first material layer is composed of a urea mixture, the particle size of the urea mixture is 3-15 mm, and the mass fraction of the urea in the urea mixture is 0.01% -0.12%; the second layer is composed of a sinter mix. By adopting the method provided by the invention, SO in the sintering flue gas 2 The discharge concentration of the catalyst is 145.68-172.62mg/m 3 The desulfurization rate is 77.8-82.5%, the flue gas desulfurization effect is good, and the emission of the flue gas SO is reduced 2 The emission concentration meets the national emission standard (200 mg/m) 3 ) And is environment-friendly.)

1. The sintering material with urea as a desulfurizing agent is characterized by comprising a bottom material laying layer, a first material layer and a second material layer from bottom to top in sequence, wherein,

the first material layer is composed of a urea mixture, the particle size of the urea mixture is 3-15 mm, and the mass fraction of urea in the urea mixture is 0.01% -0.12%;

the second layer is composed of a sinter mix.

2. The sintering material using urea as desulfurizer according to claim 1, wherein the mass fraction of urea in the urea mixture is 0.05% to 0.09%.

3. The sintering material taking urea as a desulfurizing agent according to claim 1, wherein the urea mixture further comprises iron ore powder, a fusing agent (dolomite, limestone and quicklime) and a fuel (mainly coke powder and coal powder), and the mass ratio of the iron ore powder to the fusing agent to the fuel is 0.66-0.78: 0.15 to 0.18: 0.04 to 0.06.

4. The sintering material using urea as a desulfurizing agent according to claim 1, wherein the ratio of the thickness of the first material layer to the thickness of the sintering material is 0.1-0.2.

5. The sintering material using urea as a desulfurizing agent according to claim 1, wherein the second material layer is composed of a sintering mixture, the particle size of the sintering mixture is 5-150 mm, and the thickness of the second material layer is 500-750 mm.

6. The sintering material using urea as a desulfurizing agent according to claim 5, wherein the sintering mixture is composed of iron ore powder, return ores, a flux and a fuel, and the mass ratio of the iron ore powder, the return ores, the flux and the fuel is 0.58-0.70: 0.18 to 0.28: 0.09-0.15: 0.04 to 0.06.

7. The sintering material using urea as desulfurizer according to claim 6, wherein the basicity of the sintering mixture is 1.8-2.0.

8. The sinter as claimed in claim 1, wherein the primer coating layer is made of sintered ore with a particle size of 5-40 mm, and the thickness of the primer coating layer is 70-100 mm.

9. The sintering material using urea as a desulfurizing agent according to claim 1, wherein the thickness of the sintering material is 800-1000 mm.

10. A method for sintering a sinter from urea as desulfurizing agent, which comprises sintering a sinter according to any one of claims 1 to 9,

sequentially paving a base material layer, a first material layer and a second material layer to obtain the sintered material; the first material layer is composed of a urea mixture, the particle size of the urea mixture is 3-15 mm, and the mass fraction of urea in the urea mixture is 0.01% -0.12%;

introducing air into the sintering material, and performing ignition, air draft and sintering to obtain a sintering ore; the ignition time is 1.5-3 min, the ignition temperature is 1050 +/-50 ℃, and the air draft sintering negative pressure is 7-14 kPa.

Technical Field

The invention belongs to the technical field of sintering, and particularly relates to a sintering material taking urea as a desulfurizing agent and a sintering method.

Background

The sintering material can obtain sintering ore through sintering, and the sintering ore is a raw material for blast furnace iron making. In the sintering process, because the raw materials contain sulfur impurities, a large amount of sulfides can be generated in sintering flue gas, air is polluted, and the environment is influenced. Researchers have proposed that the addition of urea to the raw material can reduce the production of sulfides during sintering, but the addition of urea to the raw material slows the rate of sinter during sintering, thereby affecting the yield of sinter.

Disclosure of Invention

In order to solve the technical problems, the invention provides a sintering material taking urea as a desulfurizing agent and a sintering method, so as to reduce the sulfide content in sintering flue gas, be environment-friendly and give consideration to the yield of sintering ores.

On one hand, the invention provides a sintering material using urea as a desulfurizing agent, which sequentially comprises a paving base material layer, a first material layer and a second material layer from bottom to top, wherein,

the first material layer is composed of a urea mixture, the particle size of the urea mixture is 3-15 mm, and the mass fraction of urea in the urea mixture is 0.01% -0.12%;

the second layer is composed of a sinter mix.

Further, in the urea mixture, the mass fraction of urea is 0.5-0.9%.

Further, the urea mixture also comprises iron ore powder, a flux (dolomite, limestone and quicklime) and fuel (coke powder and coal powder), wherein the mass ratio of the iron ore powder to the flux to the fuel is 0.66-0.78: 0.15 to 0.18: 0.04 to 0.06.

Further, the ratio of the thickness of the first material layer to the thickness of the sintering material is 0.1-0.2.

Further, the second material layer is composed of a sintering mixture, the particle size of the sintering mixture is 5-150 mm, and the thickness of the second material layer is 500-750 mm.

Further, the sintering mixture is composed of iron ore powder, return ores, a flux and fuel, and the mass ratio of the iron ore powder, the return ores, the flux and the fuel is 0.58-0.70: 0.18 to 0.28: 0.09-0.15: 0.04 to 0.06.

Further, the alkalinity of the sintering mixture is 1.8-2.0.

Further, the bottom material spreading layer is composed of sintered ore with the particle size of 5-40 mm, and the thickness of the bottom material spreading layer is 70-100 mm.

Further, the thickness of the sintering material is 800-1000 mm.

In another aspect, the present invention further provides a sintering method of a sintering material using urea as a desulfurizing agent, the sintering method comprises the steps of,

sequentially paving a base material layer, a first material layer and a second material layer to obtain the sintered material; the first material layer is composed of a urea mixture, the particle size of the urea mixture is 3-15 mm, and the mass fraction of urea in the urea mixture is 0.01% -0.12%;

introducing air into the sintering material, and performing ignition, air draft and sintering to obtain a sintering ore; the ignition time is 1.5-3 min, the ignition temperature is 1050 +/-50 ℃, and the air draft sintering negative pressure is 7-14 kPa.

One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

the invention provides a sintering material using urea as a desulfurizer and a sintering method, wherein the urea is used as the desulfurizer to prepare a mixture with a certain particle size and is distributed between a bedding material layer and a sintering mixture (a second material layer), so that sintering flue gas generated by burning the sintering mixture moves downwards to the urea under the action of air draft in the air draft sintering processThe first material layer formed by the mixture can react with the urea to remove the sulfide in the flue gas; the urea is not in direct contact with the sintering mixture, so that the urea is prevented from being in contact with water in the sintering mixture, the problem of difficult granulation is solved, the air permeability of the sintering material is improved, and the yield is improved. By adopting the method provided by the invention, SO in the sintering flue gas₂The discharge concentration of the catalyst is 145.68-172.62mg/m³The desulfurization rate is 77.8-82.5%, the flue gas desulfurization effect is good, and the emission of the flue gas SO is reduced₂The emission concentration meets the national emission standard (200 mg/m)³) And is environment-friendly.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.

FIG. 1 is a trend chart of sintering flue gas composition;

FIG. 2 is a flow chart of a sintering process in example 1 of the present invention.

Detailed Description

The present invention will be described in detail below with reference to specific embodiments and examples, and the advantages and various effects of the present invention will be more clearly apparent therefrom. It will be understood by those skilled in the art that these specific embodiments and examples are for the purpose of illustrating the invention and are not to be construed as limiting the invention.

Throughout the specification, unless otherwise specifically noted, terms used herein should be understood as having meanings as commonly used in the art. Accordingly, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. If there is a conflict, the present specification will control.

Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.

It is noted that, in this document, relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.

In order to solve the technical problems, the embodiment of the invention provides the following general ideas:

on one hand, the embodiment of the invention provides a sintering material using urea as a desulfurizing agent, which sequentially comprises a paving base material layer, a first material layer and a second material layer from bottom to top, wherein,

the first material layer is composed of a urea mixture, the particle size of the urea mixture is 3-15 mm, and the mass fraction of urea in the urea mixture is 0.01% -0.12%;

the second layer is composed of a sinter mix.

During the air draft sintering process, sulfur elements carried in the raw materials can form sulfides to enter sintering flue gas, and the Sulfides (SO) are generated₂) Can be seen in fig. 1. According to the invention, urea is prepared into particles with a certain size and then is laid between the bedding material layer and the second material layer formed by sintering the mixture, on one hand, the urea mixture is not contacted with the sintering mixture, so that the problem of difficult granulation caused by water absorption when the urea is mixed with other raw materials is avoided, and the air permeability of the second material layer formed by sintering the mixture is improved; on the other hand, the whole air permeability of the sintering material is ensured by the first material layer formed by the urea mixture, and in the sintering process, the flue gas moves downwards along with the air draft and contacts with the urea mixture, so that the sulfide in the flue gas is mixed with the urea mixture to generate a desulfurization reaction, and the sulfur content in the flue gas is reduced. By the aid of the sintering material, sintering production efficiency is guaranteed, and flue gas desulfurization efficiency is improved.

The mass fraction of the urea is too large, so that the using amount of the urea is increased, the emission reduction cost is increased, the quality of the sinter is influenced, and secondary pollution is easily caused; quality of ureaIf the fraction is too small, the emission reduction effect is greatly reduced, and the emission reduction effect is influenced. If the particle size of the urea mixture is too small, the urea particles are difficult to add to the specified height, the operation is difficult, the desulfurization effect of the urea is poor, the air permeability of the sintering material is reduced, and the quality of the sintering ore is not improved; due to SO₂Concentrate in the comparatively narrow and small one deck of sinter bed, only need to carry out the pertinence to this narrow and small one deck and add the urea mixture can, if the particle diameter of urea mixture is too big, will cause the urea mixture to exceed this narrow and small layer for it does not have pertinence, the desulfurization effect of urea that can greatly reduced equally.

In the invention, the urea raw material in the urea mixture can be industrial urea meeting the national standard GB 2440-2001, the total nitrogen content is more than or equal to 46.4%, and the particle diameter of the urea raw material is 0.85-2.80 mm. Specifically, industrial urea provided by chemical industry limited company in coal of Shanghai, Anhui province can be selected, wherein the mass fraction of nitrogen is 46.3% -50%. By using ammonium carbamate (NH) formed by thermal decomposition of urea₂COONH₄) With SO in the absorption liquid₂Reacting with harmful gas, and converting into nontoxic ammonium sulfate powder (NH)₄)₂SO₄。

Preferably, in the urea mixture, the mass fraction of urea is 0.5-0.9%.

As an implementation manner of the embodiment of the invention, the urea mixture further comprises iron ore powder, a flux (dolomite, limestone and quicklime) and a fuel (coke powder and coal powder), wherein the mass ratio of the iron ore powder to the flux to the fuel is 0.66-0.78: 0.15 to 0.18: 0.04 to 0.06.

Urea cannot be used directly as a part of the sinter because its particle size is too small to reduce the permeability of the sinter and must be mixed with iron ore powder, limestone, dolomite, quicklime and the like to prepare granules. Wherein, the iron ore powder is the raw material of the sintering ore, and the limestone, the dolomite and the quicklime are the common fusing agents in the sintering production process and can neutralize the silicon dioxide in the iron ore powder.

As an implementation manner of the embodiment of the invention, the ratio of the thickness of the first material layer to the thickness of the sintering material is 0.1-0.2.

If the first material layer (urea mixture) is too thick, the first material layer is paved above the bedding materials to influence the air permeability of the sintering material layer, the negative pressure of a main pipeline and a vertical pipe of the sintering machine is increased, the air permeability of the material layer is poor, the vertical sintering speed of the material layer is reduced, and the output of the sintering machine per unit time is reduced.

As an implementation manner of the embodiment of the invention, the second material layer is composed of a sintering mixture, the particle size of the sintering mixture is 5-150 mm, and the thickness of the second material layer is 500-750 mm.

After the granularity of the bottom paving material is too large, the reduction of high-quality grain size in finished ore is inevitably caused, and the quality of blast furnace sintering ore is reduced; however, the effect of the bedding material is seriously weakened by too fine a size of the bedding material.

As an implementation manner of the embodiment of the invention, the sintering mixture is composed of iron ore powder, return ores, a flux and fuel, and the mass ratio of the iron ore powder, the return ores, the flux and the fuel is 0.58-0.70: 0.18 to 0.28: 0.9-0.15: 0.4 to 0.6.

The iron ore powder is a raw material for iron making, and molten iron can be prepared through reduction reaction; the iron ore powder contains sulfur impurities, and sulfide is generated in the sintering process. The return fines refer to various iron-containing dusts and slags generated in various procedures (such as smelting, rolling and the like) in a part of steel production process added in the sintering batching process, such as blast furnace gravity ash, steel slag tailings, iron scales, sintering electrostatic precipitator dust and the like. The flux is generally limestone, quicklime, dolomite and the like, and has the function of forming slag with good fluidity with gangue and ash, and separating and smoothly discharging slag iron; the slag with certain alkalinity is also beneficial to desulfurization and improves the quality of pig iron. The proportion of the raw materials is controlled to prepare the sinter with good metallurgical property, thereby having high production efficiency.

As an implementation manner of the embodiment of the invention, the alkalinity of the sintering mixture is 1.8-2.0.

The alkalinity of the sintering mixture refers to CaO and SiO in the sintering mixture₂Of the sinter mixThe alkalinity is a main factor influencing the amount and the type of the liquid phase, and the amount of the liquid phase is increased along with the increase of the alkalinity, so the effect of controlling the amount of the liquid phase can be achieved by controlling the alkalinity.

As an implementation manner of the embodiment of the invention, the bedding material layer is composed of sintered ore with the grain diameter of 5-40 mm, and the thickness of the bedding material layer is 70-100 mm.

In order to protect the sintering machine trolley and ensure the thorough burning of the material layer, the large-scale sintering machine is paved with sintering ores with the thickness of 20-40 mm on the sintering machine trolley to serve as a bedding material, and the bedding material is fully paved with mixed materials for ignition sintering. When the bottom material paving process is adopted, a layer of small sintered ore with the granularity of 10-25 mm and the thickness of 20-25 mm is paved as the bottom material before the mixture is distributed, so that the purposes of protecting the fire grate, reducing the dust removal load, prolonging the service life of a fan rotor, reducing or eliminating the bonding material of the fire grate, keeping the effective air draft area, enabling the air flow to be uniformly distributed and improving the vacuum system of the sintering process are achieved.

For blast furnace iron making, the 10-20 mm grade sintered ore has good physical and chemical properties, which is beneficial to increasing pig iron yield and reducing coke consumption of a blast furnace, and the high-quality sintered ore of the grade is used as an auxiliary base material, so that sintering resources are wasted; for sintering production, the use of 10-20 mm size fraction sintered ore as the bottom layer is also disadvantageous, and because the sintering machine adopts segregation distribution, 5-8 mm size fraction material with the content of about 45% in the sintered mixture is distributed on the lower layer of the mixture and the top layer of the bottom layer. The particle size difference between the 5-8 mm mixture and the 10-20 mm coarse-grain bedding material is up to four times, the partial gap is too large, the air gap of the large-grain bedding material is filled with the small-grain mixture, so that the air permeability index of a sinter bed is poor, the passing of waste gas is influenced, the increase of the thickness of the total material layer is influenced, the yield of sinter ore is low, and the consumption of solid fuel is high. The small-grain-size sintered ore with the grain size larger than 5mm and smaller than 10mm is used as the bedding material, so that the content and the powder content of the small-grain-size sintered ore in the sintered ore entering the furnace are greatly reduced, and the enhancement of blast furnace smelting and the production and consumption reduction of the blast furnace are facilitated. The granularity of the bedding material is uniform, the size difference between the bedding material and the mixture is greatly reduced, and the partial gap between the particles is further reduced, thereby effectively improving the air gap rate at the lower part of the sinter bed, improving the air permeability of the sinter bed, and creating conditions for increasing the sinter yield and reducing the energy consumption.

As an implementation manner of the embodiment of the invention, the thickness of the sintering material is 800-1000 mm.

The thickness of the sintering material layer has great influence on sintering, the automatic heat storage effect of sintering can be improved by properly increasing the thickness of the material layer according to the actual condition of the structure of the raw material, the high-temperature retention time is prolonged, the formation and the flow of a sintering liquid phase and the crystallization of an ore phase are more sufficient, the proportion of low-strength sintering ores on the surface layer is relatively reduced, and the strength and the granularity composition of the sintering ores can be improved.

On the other hand, the embodiment of the invention also provides a sintering method for sintering the sintering material with urea as a desulfurizing agent, which comprises the following steps,

s1, sequentially paving a bottom material layer, a first material layer and a second material layer to obtain the sintered material; the first material layer is composed of a urea mixture, the particle size of the urea mixture is 3-15 mm, and the mass fraction of urea in the urea mixture is 0.01% -0.12%;

wherein, the urea mixture can be obtained by the following equipment and method: a small-sized secondary mixing granulation roller is additionally arranged in the basic sintering flow to perform mixing granulation on urea and sintering raw materials, so that layered loading in the material distribution sintering process is realized. The method comprises the following specific steps: preparing a sintering mixture and a mixture with an additive by utilizing an additionally-arranged small-sized secondary mixing granulation roller, wherein the additive is urea particles; in the sintering and distributing process, after the bottom material layer is laid, urea mixture added with urea is laid, and finally, sintering mixture is laid, so that layered loading in the sintering and distributing process is realized.

S2, introducing air into the sintering material, igniting, exhausting and sintering to obtain a sintering ore; the ignition time is 1.5-3 min, the ignition temperature is 1050 +/-50 ℃, and the air draft sintering negative pressure is 7-14 kPa.

The ignition operation is to ignite and burn the surface of the material layer on the trolley. The ignition requires sufficient ignition temperature, proper high-temperature holding time and uniform ignition along the width of the trolley. The normal ignition time is 60s, and if the ignition time is too short (less than 45s), the surface layer solid fuel is not completely ignited, and the surface layer fuel tape is difficult to be drawn, thereby influencing the normal operation of sintering.

The normal ignition temperature is 1050 ℃ +/-50 ℃, if the ignition temperature is too low, the time is too short, the solid fuel on the surface layer is not easy to be ignited to be drawn downwards, and the surface layer is in a semi-molten state after ignition. The strength of the sintered ore is not good, and a large amount of return ores are generated. If the ignition temperature is too high or the ignition time is too long, the charge surface is over-fused into a hard shell, the air permeability of the charge layer is reduced, and the productivity is affected.

The ignition aims at supplementing the insufficient heat on the surface of the mixture to sinter the surface mixture into blocks; and secondly, the fuel in the surface layer mixture starts to burn after being ignited, and the sintering process is carried out from bottom to top by means of air draft. The negative pressure is increased, the air flow velocity penetrating through the sintering material layer is increased, the sintering liquid phase crystallization time is shortened, the strength of the sintering ore is deteriorated, the ore return quantity is increased, the quality is deteriorated, and the cost is increased.

After ignition, air draft sintering is started, air quantity is controlled, a computer automatically collects waste gas temperature and air draft negative pressure, and after data recording is well done, a flue gas analyzer is used for detecting flue gas components in each flue.

The invention realizes the layered material distribution in the sintering process by additionally arranging the small-sized granulating roller in the secondary mixing process of the sintering machine; the sintering machine normally carries out a sintering and mixing process, iron ore powder, return fines, a flux, fuel and iron-containing miscellaneous materials are added into a mixing granulator for mixing, and a sintering mixture is prepared after mixing; after the primary mixing is finished, pouring the mixture into a cylindrical mixer for secondary mixing granulation, and additionally adding urea of a small granulation roller for uniformly mixing and granulation; during the material distribution process, the sintering quasi-particles added with urea are firstly paved on the lower part of the material layer, and other sintering mixture materials are continuously paved; after ignition, air draft sintering is started, air quantity is controlled, a computer automatically collects waste gas temperature and air draft negative pressure, and data recording is well carried out. The flue gas components in the flue are detected by a flue gas analyzer, and the flue gas desulfurization effect is clearly achieved by using the method.

The following will explain in detail a sintering material using urea as a desulfurizing agent and a sintering method thereof according to the present invention with reference to examples, comparative examples and experimental data.

Example 1

Embodiment 1 provides a sintering material using urea as a desulfurizing agent and a sintering method thereof, and with reference to fig. 2, the following details are provided:

1. the iron ore powder, the return fines, the flux and the fuel are pre-mixed according to the mass fractions of 60%, 20%, 15% and 5%, and then the mixture is added into a mixing granulator to be mixed to obtain a mixed material.

2. Pouring the first mixed material obtained in the step 1 into a cylindrical mixer for second mixing granulation to obtain a sintered mixture with the particle size of 5-150 mm and the alkalinity of the sintered mixture of 2.0;

3. urea, iron ore powder, a flux and fuel are mixed according to the mass ratio of 3%: 75%: 16%: 6%, mixing and granulating to obtain a urea mixture with the particle size of 3-15 mm, wherein the mass fraction of urea is 0.03%;

4. material distribution:

sequentially distributing the sintered ore, the urea mixture and the sintered mixture, specifically, paving the sintered ore with the particle size of 5-40 mm on a sintering trolley, and paving the sintered ore with the thickness of 80 mm; then, paving the urea mixture obtained in the step 3 on the sinter, wherein the paving thickness is 100 mm; and finally, paving the sintering mixture prepared in the step 2 on the urea mixture, wherein the paving thickness is 620mm, and the sintering material with the total thickness of 800mm is formed.

5. And (4) performing ignition air draft sintering on the sintering material obtained in the step (4) to obtain a sintering ore. Wherein the ignition time is 2min, the ignition temperature is 1000 ℃, and the negative pressure of air draft is 8 kPa.

Example 2

Embodiment 2 provides a sintering material using urea as a desulfurizing agent and a sintering method thereof, which specifically comprise the following steps:

1. iron ore powder, return ores, a flux and fuel are mixed according to the mass ratio of 61%: 19%: 14%: 6 percent of the raw materials are added into a mixing granulator for mixing, and a mixed material is prepared after mixing.

2. Pouring the primary mixed material obtained in the step 1 into a cylindrical mixer for secondary mixing granulation to obtain a sintered mixed material with the particle size of 5-150 mm and the alkalinity of 2.0;

3. urea, iron ore powder, a flux and fuel are mixed according to the mass ratio of 6%: 72%: 17%: 5%, mixing and granulating to obtain a urea mixture with the particle size of 3-15 mm, wherein the mass fraction of urea is 0.06%;

4. material distribution:

paving sintered ore with the particle size of 10-40 mm on a sintering trolley, wherein the paving thickness is 80 mm; then, paving the urea mixture obtained in the step 3 on the sinter, wherein the paving thickness is 110 mm; and finally, paving the sintering mixture prepared in the step 2 on the urea mixture, wherein the paving thickness is 610mm, and the sintering material with the total thickness of 800mm is formed.

5. And (4) performing ignition air draft sintering on the sintering material obtained in the step (4) to obtain a sintering ore. Wherein the ignition time is 2min, the ignition temperature is 1000 ℃, and the negative pressure of air draft is 8 kPa.

Example 3

Embodiment 3 provides a sintering material using urea as a desulfurizing agent and a sintering method thereof, which specifically comprise the following steps:

1. iron ore powder, return ores, a flux and fuel are mixed according to the mass ratio of 62%: 18%: 15%: 5 percent of the raw materials are added into a mixing granulator for mixing, and a mixed material is prepared after mixing.

2. Pouring the primary mixed material obtained in the step 1 into a cylindrical mixer for secondary mixing granulation to obtain a sintered mixed material with the particle size of 5-150 mm and the alkalinity of 2.0;

3. urea, iron ore powder, a flux and fuel are mixed according to the mass ratio of 8%: 70%: 16%: 6%, mixing and granulating to obtain a urea mixture with the particle size of 3-15 mm, wherein the mass fraction of urea is 0.08%;

4. material distribution:

paving sintered ore with the particle size of 20-40 mm on a sintering trolley, wherein the paving thickness is 80 mm; then, paving the urea mixture obtained in the step (3) on the sinter, wherein the paving thickness is 120 mm; and finally, paving the sintering mixture prepared in the step 2 on the urea mixture, wherein the paving thickness is 600mm, and the sintering material with the total thickness of 800mm is formed.

5. And (4) performing ignition air draft sintering on the sintering material obtained in the step (4) to obtain a sintering ore. Wherein the ignition time is 2min, the ignition temperature is 1000 ℃, and the negative pressure of air draft is 8 kPa.

Example 4

Embodiment 4 provides a sintering material using urea as a desulfurizing agent and a sintering method thereof, which specifically comprise the following steps:

1. iron ore powder, return ores, a flux and fuel are mixed according to the mass ratio of 63%: 18%: 14%: 5 percent of the raw materials are added into a mixing granulator for mixing, and a mixed material is prepared after mixing.

2. Pouring the primary mixed material obtained in the step 1 into a cylindrical mixer for secondary mixing granulation to obtain a sintered mixed material with the particle size of 5-150 mm and the alkalinity of 2.0;

3. urea, iron ore powder, a flux and fuel are mixed according to the mass ratio of 10%: 69%: 15%: 6%, mixing and granulating to obtain a urea mixture with the particle size of 3-15 mm, wherein the mass fraction of urea is 0.10%;

4. material distribution:

paving sintered ore with the particle size of 5-20 mm on a sintering trolley, wherein the paving thickness is 80 mm; then, paving the urea mixture obtained in the step 3 on the sinter, wherein the paving thickness is 130 mm; and finally, paving the sintering mixture prepared in the step 2 on the urea mixture, wherein the paving thickness is 590mm, and the sintering material with the total thickness of 800mm is formed.

5. And (4) performing ignition air draft sintering on the sintering material obtained in the step (4) to obtain a sintering ore. Wherein the ignition time is 2min, the ignition temperature is 1000 ℃, and the negative pressure of air draft is 8 kPa.

Comparative example 1

Comparative example 1 provides a sintering material using urea as a desulfurizing agent and a sintering method thereof, which specifically comprise the following steps:

1. iron ore powder, return ores, a flux, fuel and urea are mixed according to the mass ratio of 60%: 17%: 15%: 5%: 3 percent of the raw materials are added into a mixing granulator for mixing, and a mixed material is prepared after mixing.

2. Performing secondary mixing granulation on the primary mixed material obtained in the step 1 to obtain a sintered mixed material with the particle size of 5-150 mm and the alkalinity of 2.0;

3. material distribution:

paving sintered ore with the particle size of 5-40 mm on a sintering trolley, wherein the paving thickness is 80 mm; and then paving the sintering mixture obtained in the step 2 on the sintering ore, and paving the sintering mixture to form the sintering material with the total thickness of 800mm, wherein the thickness of the sintering material is 720 mm.

4. And (4) performing ignition air draft sintering on the sintering material obtained in the step (3) to obtain a sintering ore. Wherein the ignition time is 2min, the ignition temperature is 1000 ℃, and the negative pressure of air draft is 8 kPa.

In the sintering processes of examples 1 to 3 and comparative example 1, the computer automatically collected the exhaust gas temperature and the negative pressure of the draft, and after data recording, the blower was turned off. And (3) detecting the smoke components in each flue by using a smoke analyzer, and detecting the emission concentration of the smoke components by using a dioxin method. And the obtained sintered ore was subjected to metallurgical property test, as shown in table 1.

Comparative example 2

Comparative example 2 provides a sinter and a sintering method, and with reference to example 1, comparative example 2 differs from example 1 in that: the particle size of the urea mixture is 4.0-5.0 mm, and the mass fraction of urea in the urea mixture is 0.3%.

TABLE 1

Numbering	SO in flue gas2Emission concentration/(mg/m)3)	Drum strength/% of sinter
			Example 1	172.62	72.5
Example 2	145.68	73.6
			Example 3	158.65	72.8
Example 4	159.23	73.2
			Comparative example 1	172.53	72.4
Comparative example 2	132.01	72.9

As can be seen from the data in Table 1, the SO in the sintering flue gas of the sintering material provided in examples 1-4 of the present invention₂The discharge concentration of the catalyst is 145.68-172.62mg/m³The method has the advantages of good flue gas desulfurization effect, environmental friendliness and 72.5-73.6% of the drum strength of the sinter. The mass fraction of the sulfide in the sintering flue gas of the sintering material provided by the comparative examples 1-2 is 132.01-172.53mg/m³The drum strength of the sintered ore is 72.4-72.9%, and the flue gas desulfurization is inferior to that of examples 1-4.

The invention provides a sintering material using urea as a desulfurizer and a sintering method, wherein urea is used as the desulfurizer to prepare a mixture with a certain particle size and is distributed on a bedding material layerAnd a sintering mixture (a second material layer), so that in the process of air draft sintering, sintering flue gas generated by combustion of the sintering mixture moves downwards to the first material layer formed by the urea mixture under the action of air draft, and sulfides in the flue gas can react with the urea, so that the sulfides in the flue gas are removed; the urea is not in direct contact with the sintering mixture, so that the urea is prevented from being in contact with water in the sintering mixture, the problem of difficult granulation is solved, the air permeability of the sintering material is improved, and the yield is improved. By adopting the method provided by the invention, the mass fraction of sulfide in the sintering flue gas is 145.68-172.62mg/m³The flue gas desulfurization effect is good, and the method is environment-friendly.

Finally, it should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.