CN110819792A - Method for producing pre-reduced sinter - Google Patents
Method for producing pre-reduced sinter Download PDFInfo
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- CN110819792A CN110819792A CN201911027984.1A CN201911027984A CN110819792A CN 110819792 A CN110819792 A CN 110819792A CN 201911027984 A CN201911027984 A CN 201911027984A CN 110819792 A CN110819792 A CN 110819792A
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B1/00—Preliminary treatment of ores or scrap
- C22B1/14—Agglomerating; Briquetting; Binding; Granulating
- C22B1/16—Sintering; Agglomerating
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Abstract
The invention discloses a method for producing pre-reduced agglomerate, which comprises the steps of distributing lump ore in the middle lower part of a pre-reduced agglomerate layer according to a proportion, removing crystal water by utilizing the lump ore to absorb heat, preventing the lower pre-reduced agglomerate from being excessively melted, and simultaneously carrying out pretreatment on the lump ore, improving the metallurgical property of the lump ore and increasing the charging proportion of the lump ore; the carbon-containing balls are distributed on the surface of the upper-layer pre-reduction sintering material, so that the problem of insufficient heat supply of the upper-layer sintering material layer can be solved, the reducing atmosphere of the upper-layer sintering material is increased, and the strength and metallization rate of the pre-reduction sintering ore are improved.
Description
Technical Field
The invention belongs to the technical field of ironmaking production, and particularly relates to a method for producing pre-reduced sinter.
Background
The energy consumption of the iron making process accounts for about 70 percent of the total energy consumption of steel production. The high-alkalinity sinter and lump ore are important iron-containing raw materials used by the blast furnace, and form an iron-containing furnace charge structure of the blast furnace together with the acid oxidation pellet ore. In order to improve the energy structure of the iron-making process, the raw fuel used by the blast furnace must be reconsidered.
The pre-reduction sinter is prepared by adding a reducing agent into sintering raw materials, and reducing while agglomerating to produce sinter containing metallic iron and ferrous oxide. Since the ordinary sintered ore starts to shrink slowly after 1150 ℃, the pressure difference of the blast furnace after the ordinary sintered ore enters the furnace is high, and when the temperature of the ordinary sintered ore exceeds 1400 ℃, the ordinary sintered ore shrinks sharply, and the pressure difference is reduced after the ordinary sintered ore is completely melted. When the pre-reduced sintered ore is used, the shrinkage before 1400 ℃ is relatively small, the blast furnace pressure difference is also small, but the pre-reduced sintered ore can be rapidly shrunk and completely melted at 1400 ℃, and the high-temperature performance is good. Therefore, when the pre-reduced sintered ore is used in the blast furnace, the thickness of the blast furnace reflow zone is reduced, the furnace pressure difference is reduced, and the effect of improving the blast furnace productivity is great.
The common sinter is completely reduced in the blast furnace, and the reduction behavior is strictly limited by the carbon-oxygen reduction balance in the blast furnace; the prereduced sinter may be partially reduced on the sintering machine by means of a reducing agent, the reduction of which in a blast furnace is effected by CO/CO2The restriction of the reaction equilibrium is small, so the use of the pre-reduced sinter in the blast furnace becomes a great breakthrough of the ironmaking technology.
One important problem in producing pre-reduced sinter is: the carbon distribution amount is increased, the width of a combustion area is increased, and the temperature of a material layer is increased. Due to the heat storage effect, the bottom pre-reduced sinter is easily over-melted. The excessive melting of the pre-reduced sinter not only reduces the metallization rate of the pre-reduced sinter, but also deteriorates the air permeability of the material bed and even burns out the grate.
Lump ore, particularly limonite lump ore, is directly smelted in a blast furnace, and problems such as cracking, poor reflow property and the like are caused. The content of the crystal water of the limonite lump ore is generally more than 5 percent, and the crystal water is decomposed and absorbs heat at the temperature of 400-500 ℃, so that the lump ore is more seriously cracked, and the metallurgical performance is poorer. The high-crystallization lump ore has rich resources and low price, but can not directly enter a blast furnace without pretreatment.
Thesis dayThe research and development of a novel pre-reduction sintering technology provides that: adding dolomite (CaCO) into the sinter3·MgCO3) The temperature of the molten liquid is increased to inhibit the over-melting, but the method causes the Mg content in the sintering material to be excessive, thereby being not beneficial to the slagging of the blast furnace. The paper also proposes to suppress melting of carbonaceous material after combustion by using a pseudo-particle structure in which a surface of a particle core is coated with a CaO component, iron ore (iron oxide), and a carbonaceous material is coated on the outer portion of the particle core, and firing pseudo-particles composed of a 3-layer structure.
The article "experimental study of using lump iron ore as sintering bedding material" proposes a method for pretreating lump ore while replacing sintered ore as bedding material, which can improve sintering productivity, reduce sintering energy consumption, and simultaneously remove harmful impurities such as crystal water and sulfur of lump ore, but the lump ore is inevitably burst when used as bedding material, and the generated dust is easily sucked into a suction pipeline, thereby increasing the dust content in sintering waste gas.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to solve the technical problems that lump ore is distributed at the middle lower part of a pre-reduction sinter bed according to the proportion, crystal water is removed by utilizing the lump ore to absorb heat, the lower pre-reduction sinter is prevented from being excessively melted, meanwhile, the lump ore is pretreated, the metallurgical property of the lump ore is improved, and the charging proportion of the lump ore is improved; the carbon-containing balls are distributed on the surface of the upper-layer pre-reduction sintering material, so that the problem of insufficient heat supply of the upper-layer sintering material layer can be solved, the reducing atmosphere of the upper-layer sintering material is increased, and the strength and metallization rate of the pre-reduction sintering ore are improved.
In order to realize the purpose of the invention, the technical scheme adopted by the invention is as follows:
a method of producing pre-reduced sinter, comprising: the method comprises the following steps of distributing materials on an upper layer, a middle layer and a lower layer, adding lump ores with different proportions to the middle layer and the lower layer, and adding carbon-containing pellets with different proportions to the upper layer, wherein the method specifically comprises the following steps:
1) the sintering raw material, fuel and lump ore form a lower-layer pre-reduction sintering material, wherein the mass fraction of the fuel is 20-25%, and the mass fraction of the lump ore is 10-20%; the sintering raw material, fuel and lump ore form a middle-layer pre-reduction sintering material, wherein the mass fraction of the fuel is 28-33%, and the mass fraction of the lump ore is 5-15%; the sintering raw material and the fuel form an upper layer pre-reduction sintering material, wherein the mass fraction of the fuel is 25-30%;
2) sequentially distributing a bottom layer pre-reduction sintering material, a middle layer pre-reduction sintering material and an upper layer pre-reduction sintering material into a sintering trolley, wherein the bottom layer pre-reduction sintering material accounts for 25-35% of the total material amount, the middle layer pre-reduction sintering material accounts for 35-45% of the total material amount, and the upper layer pre-reduction sintering material accounts for 25-35% of the total material amount;
3) injecting carbon-containing pellets into the upper-layer pre-reduction sintering material by using a rotary ball distributor, wherein the injection depth of the carbon-containing pellets is 50-100 mm, and the injection amount is 50-120 pellets per square meter; wherein the amount of the carbon-containing pellets injected into the edge sintering material is 1-2.5 times of that of the middle sintering material; igniting and exhausting air to perform pre-reduction sintering to obtain pre-reduction sintered ore;
the carbon-containing pellets are prepared by the following method: fully and uniformly mixing 60-70% of iron ore concentrate and 30-40% of bituminous coal, and then adding quicklime into the mixture to form a mixture; adjusting the addition amount of quicklime to enable the binary alkalinity of the mixture to be 1.8-2.2; adding water into the mixture, fully stirring and uniformly mixing the mixture in a mixer, and carrying out hot press molding on the uniformly mixed mixture by a ball press machine, wherein the molding pressure is 20-30 MPa; the hot pressing temperature is 550-650 ℃; the hot pressing time is 10 min-20 min; the diameter of the obtained hot-pressed pellet is 8-15 mm; the bituminous coal is one or more of fat coal, gas fat coal, coking coal and gas coal.
The lump ore has a grain size of 10-15 mm and a crystal water content of less than 10%.
The fuel is coke powder, anthracite powder, semicoke and biomass carbon powder.
The binary alkalinity of the pre-reduced sintering materials of the upper layer, the middle layer and the lower layer is the same as that of the carbon-containing pellets and is 1.8-2.2.
Compared with the prior art, the invention has the beneficial effects that: 1) according to the invention, lump ore is distributed at the middle lower part of the pre-reduction sinter bed according to a proportion, and crystal water is removed by utilizing the lump ore to absorb heat, so that the lower pre-reduction sinter is prevented from being excessively melted, and meanwhile, the lump ore is pretreated, the metallurgical property of the lump ore is improved, and the charging proportion of the lump ore is increased. 2) According to the invention, the carbon-containing balls are distributed on the surface of the upper-layer pre-reduction sintering material, so that the problem of insufficient heat supply of the upper-layer sintering material layer can be solved, the reducing atmosphere of the upper-layer sintering material is increased, and the strength and metallization rate of the pre-reduction sintering ore are improved.
Detailed Description
The following description is given with reference to specific examples:
example 1
The material is distributed in three layers of an upper layer, a middle layer and a lower layer, lump ores with different proportions are distributed in the middle layer and the lower layer, and carbon-containing pellets with different proportions are added in the upper layer. The sintering raw material, the fuel and the lump ore form a lower-layer pre-reduction sintering material, wherein the mass fraction of the fuel is 22%, and the mass fraction of the lump ore is 14%; the sintering raw material, fuel and lump ore form a middle-layer pre-reduction sintering material, wherein the mass fraction of the fuel is 29 percent, and the mass fraction of the lump ore is 8 percent; the sintering raw material and the fuel form an upper layer pre-reduction sintering material, wherein the mass fraction of the fuel is 27%. The fuel is coke powder, the grain size of lump ore is 10-15 mm, and the content of crystal water is 8%.
Sequentially distributing a bottom layer pre-reduction sintering material, a middle layer pre-reduction sintering material and an upper layer pre-reduction sintering material into a sintering trolley, wherein the bottom layer pre-reduction sintering material accounts for 28% of the total material amount, the middle layer pre-reduction sintering material accounts for 42% of the total material amount, and the upper layer pre-reduction sintering material accounts for 30% of the total material amount; the binary basicity of the sinter mix was 1.9.
Fully and uniformly mixing 64 percent of iron ore concentrate and 36 percent of bituminous coal, and then adding quicklime into the mixture to form a mixture; adjusting the addition amount of quicklime to make the binary basicity (CaO/SiO) of the mixture2) Is 1.9; adding water into the mixture, and fully stirring and uniformly mixing the mixture in a mixer. Carrying out hot press molding on the uniformly mixed mixture by a ball press machine, wherein the molding pressure is 24 MPa; the hot pressing temperature is 580 ℃; the hot pressing time is 17 min; the diameter of the obtained hot-pressed pellet is 10-12 mm; the bituminous coal is the matching of fat coal and coking coal. The carbon-containing pellets are shot into the pre-reduced sintering material on the upper layer by a rotary ball distributor, the shot depth of the carbon-containing pellets is 80mm, and the shot depth isThe input amount is 60 per square meter; the amount of the carbon-containing pellets injected into the edge sintering material is 1.5 times of that of the middle sintering material; and (5) igniting and exhausting air to perform pre-reduction sintering to obtain pre-reduction sintered ore.
The obtained pre-reduced sintered ore was examined and compared with those obtained by the conventional method, as shown in table 1. The metallurgical properties of the screened treated lump ore were measured and compared with those of untreated lump ore, and as shown in table 2, it was found that the metallurgical properties of both the pre-reduced sintered ore and the lump ore were improved.
TABLE 1 metallurgical Performance Table/% of prereduced sinter
TABLE 2 lump ore burst index and reduction degree%
As can be seen from tables 1 and 2, the drum strength of the pre-reduced sinter is improved by 8.4 percent after the method is applied, the metallization rate is improved by 5.3 percent, and the RDI+3.156.2 percentage points are increased; the burst index of the treated lump ore is improved by 1.81 percent, and the reduction degree is improved by 5.1 percent.
Example 2
The material is distributed in three layers of an upper layer, a middle layer and a lower layer, lump ores with different proportions are distributed in the middle layer and the lower layer, and carbon-containing pellets with different proportions are added in the upper layer. The sintering raw material, fuel and lump ore form a lower-layer pre-reduction sintering material, wherein the mass fraction of the fuel is 25%, and the mass fraction of the lump ore is 18%; the sintering raw material, fuel and lump ore form a middle-layer pre-reduction sintering material, wherein the mass fraction of the fuel is 32%, and the mass fraction of the lump ore is 15%; the sintering raw material and the fuel form an upper layer pre-reduction sintering material, wherein the mass fraction of the fuel is 28%. The fuel used is anthracite powder and semicoke, the grain size of lump ore is 10-15 mm, and the content of crystal water is 6%.
Sequentially distributing a bottom layer pre-reduction sintering material, a middle layer pre-reduction sintering material and an upper layer pre-reduction sintering material into a sintering trolley, wherein the bottom layer pre-reduction sintering material accounts for 32% of the total material amount, the middle layer pre-reduction sintering material accounts for 40% of the total material amount, and the upper layer pre-reduction sintering material accounts for 28% of the total material amount; the binary basicity of the sinter mix was 2.1.
Fully and uniformly mixing 68% of iron ore concentrate and 32% of bituminous coal, and then adding quicklime into the mixture to form a mixture; adjusting the addition amount of quicklime to make the binary basicity (CaO/SiO) of the mixture2) Is 2.1; adding water into the mixture, and fully stirring and uniformly mixing the mixture in a mixer. Carrying out hot press molding on the uniformly mixed mixture by a ball press machine, wherein the molding pressure is 28 MPa; the hot pressing temperature is 640 ℃; the hot pressing time is 13 min; the diameter of the obtained hot-pressed pellet is 10-15 mm; the bituminous coal is a mixture of gas fat coal and fat coal. Injecting carbon-containing pellets into the upper layer of pre-reduced sintering material by using a rotary ball distributor, wherein the injection depth of the carbon-containing pellets into the material layer is 60mm, and the injection amount is 100 per square meter; the amount of the carbon-containing pellets injected into the edge sintering material is 2 times of that of the middle sintering material; and (5) igniting and exhausting air to perform pre-reduction sintering to obtain pre-reduction sintered ore.
The obtained pre-reduced sintered ore was examined and compared with the pre-reduced sintered ore of normal burden distribution, as shown in table 3. The metallurgical properties of the screened treated lump ore were measured and compared with those of untreated lump ore, and as shown in table 4, it was found that the metallurgical properties of both the pre-reduced sintered ore and the lump ore were improved.
TABLE 3 pre-reduction sinter metallurgy Performance table/%)
TABLE 4 lump ore decrepitation index and reduction degree%
As can be seen from tables 3 and 4, the drum strength of the pre-reduced sinter is improved by 8.9 percent, the metallization rate is improved by 5.8 percent, and the RDI is improved after the method is applied+3.15The improvement is 7.1 percentage points; the burst index of the treated lump ore is improved by 1.83 percentage points,the reduction degree is improved by 4.8 percentage points.
Claims (3)
1. A method of producing pre-reduced sinter, comprising: the method comprises the following steps of distributing materials on an upper layer, a middle layer and a lower layer, adding lump ores with different proportions to the middle layer and the lower layer, and adding carbon-containing pellets with different proportions to the upper layer, wherein the method specifically comprises the following steps:
(1) the sintering raw material, fuel and lump ore form a lower-layer pre-reduction sintering material, wherein the mass fraction of the fuel is 20-25%, and the mass fraction of the lump ore is 10-20%; the sintering raw material, fuel and lump ore form a middle-layer pre-reduction sintering material, wherein the mass fraction of the fuel is 28-33%, and the mass fraction of the lump ore is 5-15%; the sintering raw material and the fuel form an upper layer pre-reduction sintering material, wherein the mass fraction of the fuel is 25-30%;
(2) sequentially distributing a bottom layer pre-reduction sintering material, a middle layer pre-reduction sintering material and an upper layer pre-reduction sintering material into a sintering trolley, wherein the bottom layer pre-reduction sintering material accounts for 25-35% of the total material amount, the middle layer pre-reduction sintering material accounts for 35-45% of the total material amount, and the upper layer pre-reduction sintering material accounts for 25-35% of the total material amount;
(3) injecting carbon-containing pellets into the upper-layer pre-reduction sintering material by using a rotary ball distributor, wherein the injection depth of the carbon-containing pellets is 50-100 mm, and the injection amount is 50-120 pellets per square meter; wherein the amount of the carbon-containing pellets injected into the edge sintering material is 1-2.5 times of that of the middle sintering material; igniting and exhausting air to perform pre-reduction sintering to obtain pre-reduction sintered ore;
the carbon-containing pellets are prepared by the following method: fully and uniformly mixing 60-70% of iron ore concentrate and 30-40% of bituminous coal, and then adding quicklime into the mixture to form a mixture; adjusting the addition amount of quicklime to enable the binary alkalinity of the mixture to be 1.8-2.2; adding water into the mixture, fully stirring and uniformly mixing the mixture in a mixer, and carrying out hot press molding on the uniformly mixed mixture by a ball press machine, wherein the molding pressure is 20-30 MPa; the hot pressing temperature is 550-650 ℃; the hot pressing time is 10 min-20 min; the diameter of the obtained hot-pressed pellet is 8-15 mm; the bituminous coal is one or more of fat coal, gas fat coal, coking coal and gas coal.
2. The method for producing pre-reduced sintered ore according to claim 1, characterized in that: the lump ore has a grain size of 10-15 mm and a crystal water content of less than 10%.
3. The method for producing pre-reduced sintered ore according to claim 1, characterized in that: the fuel is coke powder, anthracite powder, semicoke and biomass carbon powder.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113801991A (en) * | 2020-06-16 | 2021-12-17 | 上海梅山钢铁股份有限公司 | Method for improving quality of sinter |
| CN114317949A (en) * | 2021-12-21 | 2022-04-12 | 马鞍山钢铁股份有限公司 | Method for strengthening sintering of upper material layer |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104419824B (en) * | 2013-09-05 | 2016-11-16 | 鞍钢股份有限公司 | A kind of distributing method producing prereduced sinter |
| CN106350666A (en) * | 2016-09-12 | 2017-01-25 | 鞍钢股份有限公司 | Super-thick bed layer sintering production method |
| CN108754131A (en) * | 2018-06-14 | 2018-11-06 | 鞍钢股份有限公司 | A kind of sintering production method of optimization fuel collocation |
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2019
- 2019-10-28 CN CN201911027984.1A patent/CN110819792A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104419824B (en) * | 2013-09-05 | 2016-11-16 | 鞍钢股份有限公司 | A kind of distributing method producing prereduced sinter |
| CN106350666A (en) * | 2016-09-12 | 2017-01-25 | 鞍钢股份有限公司 | Super-thick bed layer sintering production method |
| CN108754131A (en) * | 2018-06-14 | 2018-11-06 | 鞍钢股份有限公司 | A kind of sintering production method of optimization fuel collocation |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113801991A (en) * | 2020-06-16 | 2021-12-17 | 上海梅山钢铁股份有限公司 | Method for improving quality of sinter |
| CN114317949A (en) * | 2021-12-21 | 2022-04-12 | 马鞍山钢铁股份有限公司 | Method for strengthening sintering of upper material layer |
| CN114317949B (en) * | 2021-12-21 | 2023-10-27 | 马鞍山钢铁股份有限公司 | Reinforced sintering method for upper material layer |
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