CN113416814B - Method for realizing zero emission of refining slag of LF (ladle furnace) - Google Patents
Method for realizing zero emission of refining slag of LF (ladle furnace) Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/0087—Treatment of slags covering the steel bath, e.g. for separating slag from the molten metal
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- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C13/00—Fibre or filament compositions
- C03C13/06—Mineral fibres, e.g. slag wool, mineral wool, rock wool
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B3/00—General features in the manufacture of pig-iron
- C21B3/02—General features in the manufacture of pig-iron by applying additives, e.g. fluxing agents
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- C21—METALLURGY OF IRON
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- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B1/00—Preliminary treatment of ores or scrap
- C22B1/14—Agglomerating; Briquetting; Binding; Granulating
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Abstract
The invention relates to the technical field of slag discharge treatment, in particular to a method for realizing zero discharge of refining slag in an LF (ladle furnace). The method comprises the following steps: s1, after the continuous casting is finished, discharging part of LF refining slag, and recycling the rest of LF refining slag and molten steel; s2, cooling the discharged LF refining slag and then crushing the cooled LF refining slag into powder; s3, adding the powdery LF refining slag into the sinter raw material; s4, adding the sintered ore into a blast furnace; s5, forming a raw material of slag micro powder after water quenching of blast furnace slag and forming a raw material for making rock wool by using blast furnace slag. The method is characterized in that the discharged part of LF refining slag after steel making recycling is added into a sintering raw material, the prepared sintering ore is used as a raw material of a blast furnace, and the blast furnace slag is generated through blast furnace smelting and then is used as a raw material for producing slag micro powder or rock wool, so that zero emission of the LF refining slag is realized, the fluidity of the blast furnace slag is improved, the wall thickness of the blast furnace is prevented, a furnace cylinder is activated, and the smooth degree of the blast furnace is improved.
Description
Technical Field
The invention relates to the technical field of slag discharge treatment, in particular to a method for realizing zero discharge of refining slag in an LF (ladle furnace).
Background
The LF ladle refining furnace has good refining effect on improving the purity of molten steel, homogenizing the components and temperature of the molten steel and removing non-metallic inclusions in the molten steel. One part of LF refining slag generated in the production process is recycled, but in order to prevent the recycling enrichment of harmful element S, one part of LF refining slag needs to be quantitatively removed, so that the part of LF refining slag forms solid waste to be removed, and certain influence is caused on the environment. The discharged LF refining slag also contains a large amount of CaO, MgO and CaF2Etc. of beneficial ingredients, andthe enriched S content can be easily removed from most of the links of sintering and blast furnace smelting, and the integral quality of the molten iron cannot be influenced. And CaF contained in LF refining slag2The method can effectively reduce the viscosity of the blast furnace slag, improve the fluidity of the slag iron, facilitate the separation of the slag iron, prevent the wall thickness of the blast furnace, and play a positive role in activating the hearth to promote the high-yield smoothness of the blast furnace and discharging alkali metal. The rich MgO and CaO in the LF furnace can reduce the addition amount of the solvent in the sinter and CaCO3And MgCO3Increased CO by decomposition2Has great effect on the discharge in the air and the environmental protection. At present, blast furnace slag is used as a raw material of slag micro powder after water quenching or used as a raw material for rock wool production after slag discharging, and zero discharge of the blast furnace slag is realized.
Chinese patent 'CN 201910256361.5' discloses a thermal state utilization method of LF refining top slag, which comprises the steps of pouring the residual molten steel after continuous casting and LF refining slag into molten iron treated by KR, and then adding the molten iron and the molten iron into a converter for converting.
Chinese patent 'CN 104278131A' discloses a method for recycling refining slag, which is to add the refining slag into oxides such as ore to modify, cool and solidify the modified refining slag and recycle the modified refining slag.
The invention patent with publication number CN101956043A discloses a recycling method of steelmaking slag, after the molten steel is poured, firstly 2-3 tons of molten steel are contained in a recycling ladle, then 2 tons of slag are poured into the recycling ladle, and 50kg of covering agent is added. The recovered ladle is transported to an electric furnace process by a transport vehicle, the residue and the molten iron are poured into the electric furnace together, and the residue is still rich in CaO and Al2O3And the slag is in a liquid state, and can be poured into an electric furnace to replace lime for dephosphorization and desulfurization, so that the lime consumption is reduced, and meanwhile, the heat in the slag is effectively recycled, the consumption of the electric furnace is reduced, and the pollution to the environment is avoided.
The invention patent with publication number CN101403021A provides a method for utilizing steel slag, namely an electric furnace → LF refining (VD vacuum degassing) → die casting production process flow to generate the steel slag utilization method, wherein a slagging material is added into an LF ladle refining furnace for refining, the slagging material is added into each ton of molten steel for 20kg-50kg, then casting is carried out, the slag of the ladle furnace and the rest of the molten steel after casting are returned to the electric furnace for smelting, the slagging material is added into the electric furnace, and the slagging material is added into each ton of the molten steel for 50kg-70 kg. The addition of slag-making material lime is reduced in the electric furnace smelting process, and the power supply of the electric furnace is reduced. And for steel types needing degassing, refining in an LF ladle refining furnace, adding a slagging material, sending the molten steel to a VD vacuum degassing furnace for degassing after slagging is finished, then casting, and returning the slag of the ladle furnace and the residual molten steel after casting to an electric furnace for smelting.
The LF ladle refining slag is basically treated in the steel-making process links such as a converter, an electric furnace, desulfurization pretreatment or VD (vacuum distillation), but the LF refining slag enriched with harmful elements is not further treated, so that a large part of LF refining slag is directly discharged after being recycled, the environment is polluted, some LF refining slag and steel slag are mixed and then subjected to magnetic separation, magnetized powder is added into the mixture for sintering, the LF refining slag contains few iron and is not magnetized at all, and the mixture which cannot participate in sintering can only be discharged along with converter tailings.
Disclosure of Invention
The invention aims at the defects and provides a method for realizing zero emission of LF refining slag, which is characterized in that the part of LF refining slag discharged after steel making recycling is added into a sintering raw material, the sintering raw material is sintered into a sintering ore to be used as a raw material of a blast furnace, and the sintering ore is smelted into blast furnace slag to be used as a raw material for producing slag micropowder or rock wool, so that the zero emission of the LF refining slag is realized, the flowability of the blast furnace slag is improved, the wall thickness of the blast furnace is prevented, a furnace cylinder is activated, and the smooth degree of the blast furnace is improved.
In order to achieve the purpose, the technical scheme of the invention is as follows:
the method for realizing zero emission of LF refining slag comprises the following steps of preparing 6-8% of SiO by mass percent250-60% of CaO, 7-10% of MgO and 15-22% of Al2O36.0 to 8.0 percent of CaF20.5% -1.5% of S;
the method comprises the following steps of,
s1, after the continuous casting molten steel is cast, discharging 30-40 wt% of LF refining slag in a ladle, and continuously recycling the rest of LF refining slag and the residual molten steel;
s2, cooling the discharged LF refining slag, and then crushing the slag into powder, wherein the proportion of the powder with the particle size of more than 3mm in the refining slag is required to be less than 5 wt%;
s3, adding the powdery LF refining slag into a sinter raw material for sintering; the proportion of LF refining slag in the sintered ore is 0.8wt% -1.2 wt%; CaF in sinter2Increase of 0.05wt% to 0.10wt%, Al2O3The increase of (A) is 0.10wt% to 0.24wt%, and the increase of MgO in the sintered ore is 0.04wt% to 0.09 wt%; controlling the binary alkalinity of the sintering ore added with the LF refining slag to be 1.8-2.0;
s4, adding the sintered ore into a blast furnace; controlling the binary alkalinity of the blast furnace slag to be 1.15-1.20; al in blast furnace slag2O3Is controlled in the range of less than 17 wt%;
CaF in blast furnace slag2、Al2O3And the amount of increase in MgO are calculated as follows,
△X1=△X2AC/B
in the formula, Delta X1Is the increment of X component in the blast furnace slag,%;
△X2is the increase of X component in the sinter,%;
a is the iron-ore ratio of the blast furnace;
b is the slag-iron ratio of the blast furnace;
c is the proportion of the sintered ore in the total burden of the blast furnace;
the proportion of the sintered ore in the total burden amount of the blast furnace is 70-80 wt%;
s5, forming a raw material of slag micro powder after water quenching of blast furnace slag and forming a raw material for making rock wool by using blast furnace slag.
Further, the sintered ore portion formed in S3 was indexed as follows: CaF2The content is 0.11-0.16 wt%; MgO content of 2.55-2.60 wt%; al (Al)2O3The content is 1.99-2.13wt%, and the rotating drum index is 78-79%.
Further, the blast furnace slag part index and the blast furnace utilization factor in S4 are as follows: CaF2The content is 0.38-0.59 wt%; MgO content of 8.51-8.72 wt%; al (Al)2O3The content is 15.36-15.94 wt%; the utilization coefficient of the blast furnace is 4.05-4.1 tons/(cubic meter. day).
Further, in S4, CaF in blast furnace slag2An increase of 0.17wt% to 0.38 wt%; the increase amount of MgO in the blast furnace slag is 0.13-0.34 wt%; al (Al)2O3The increase of (b) is 0.33wt% to 0.91 wt%.
The invention has the beneficial effects that:
firstly, the LF refining slag accounting for 0.8-1.2 wt% is added into the sinter to save the consumption of quicklime; the quicklime is made of limestone (CaCO)3) Carbon dioxide is generated in the processes of limestone decomposition and fuel consumption after heating decomposition; according to statistics, the refining slag of the LF furnace is added, so that the cost is saved, and the emission of carbon dioxide is reduced by about 8kg per ton of sintering ore;
secondly, the circulating LF refining slag is completely added with sinter, granulated slag is formed after blast furnace smelting and is used as a raw material of slag micro powder, and the discharged slag is used as a raw material for producing rock wool under special conditions, so that zero emission of solid waste of the LF refining slag is realized;
furthermore, CaF in LF refining slag is utilized2Promoting the liquid phase generation of the sinter, improving the continuous crystal strength of the sinter, and utilizing CaF in a blast furnace2The low melting point characteristic improves the fluidity of the slag iron, promotes the separation and permeation of the slag iron, prevents the furnace wall from being thickened and ensures the smooth high yield of the blast furnace;
in addition, part of the LF refining slag is added into the sintered ore, so that the enrichment of harmful elements such as S and the like in the recycling process of the LF refining slag is reduced, and the influence of the enrichment of the harmful elements on the refining effect is also reduced.
Detailed Description
In order to make those skilled in the art better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The method for realizing zero emission of LF refining slag comprises the following steps of preparing 6-8% of SiO by mass percent250-60% of CaO, 7-10% of MgO and 15-22% of Al2O36.0 to 8.0 percent of CaF20.5% -1.5% of S; the method comprises the following steps:
s1, after the continuous casting is finished, discharging part of LF refining slag, and recycling the rest of LF refining slag and molten steel;
s2, cooling the discharged LF refining slag and then crushing the cooled LF refining slag into powder;
s3, adding the powdery LF refining slag into a sinter raw material to sinter into an ore;
s4, adding the sintered ore into a blast furnace;
s5, forming a raw material of slag micro powder after water quenching of blast furnace slag and forming a raw material for making rock wool by using blast furnace slag.
Preferably, in S1, after the continuous casting molten steel is cast, discharging 30-40 wt% of LF refining slag in a ladle, and continuously recycling the rest of LF refining slag and the residual molten steel;
preferably, in S2, the requirements for the pulverization particle size of the discharged LF refining slag are: the proportion of the powder with the grain diameter larger than 3mm in the refining slag is less than 5wt percent, because the LF refining slag with smaller grain diameter is easy to be mixed in the sintering mixture, and alkaline substances CaO, MgO and CaF in the slag are easier to be caused2Fully mixing with the acidic substance SiO in the mixture2、Al2O3Low melting point materials are formed so that sufficient liquid phase is obtained at low fuel consumption to improve the strength and metallurgical properties of the sintered ore.
Preferably, in S3, the addition proportion of LF refining slag in sintered ore is 0.8wt% -1.2 wt%; according to the equivalent amount of quicklime and fluorite added in the refining process of the steel-making LF furnace and the slag discharging amount in the steel-making tapping process, the method can be obtained as follows: the generation amount of LF refining slag is about 1wt% of the steel yield; the ratio of molten iron to molten steel is about 0.8; the ratio of the sintered ore to the molten iron is about 1.16-1.33; and then calculating the proportion of the completely digested LF refining slag in the sinter as follows: 0.94wt% -1.08wt%, therefore, considering special conditions such as slag discharging and the like, the proportion of the LF furnace refining slag in sintering is determined as follows: 0.8wt% -1.2 wt%.
0.8 to 1.2 weight percent of LF refining slag is added into the sintered ore, and CaF is added into the sintered ore2The increase is: 0.05wt% -0.10wt%, and trace CaF2The method does not compete for CaO with calcium ferrite, does not cause the reduction of the content of the calcium ferrite, does not influence the mechanical strength of the sinter, and can promote the generation of a liquid phase to increase the strength of the continuous crystal; the "increase" in S3 is the content of the corresponding component in the sintered ore to which the LF refining slag was added, which is increased relative to the content of the corresponding component in the sintered ore to which the LF refining slag was not added.
In order to ensure the stable alkalinity and metallurgical performance of the sintered ore, the alkalinity of the sintered ore added with LF refining slag is controlled to be 1.8-2.0;
Al2O3the increase of (A) is 0.10wt% to 0.24wt%, and the influence on the strength of the sintered ore is limited; the increase in S in the sinter was about: 0.0010 to 0.0045 weight percent, and very trace, the desulfurization load of the blast furnace is hardly increased; the amount of MgO added to the sintered ore was: 0.04wt% -0.09wt%, and the increment is small, so that the strength of the sintered ore is not influenced;
preferably, in S4, the addition proportion of the sinter added with the LF refining slag in the blast furnace is 70-80 wt% of the iron-containing material of the blast furnace; and calculating the component increase amount of the blast furnace slag caused by the change of the components of the sintering ore by using the blast furnace ore iron ratio and the blast furnace slag iron ratio, wherein the increase amount in S4 is the content of the corresponding component in the blast furnace slag increased relative to the content of the corresponding component in the blast furnace slag without the LF refining slag. The specific calculation method is as follows:
△X1=△X2AC/B (equation 1)
In the formula, Delta X1Is the increment of X component in the blast furnace slag,%;
△X2is the increase of X component in the sinter,%;
a is the iron-ore ratio of the blast furnace;
b is the slag-iron ratio of the blast furnace;
c is the proportion of the sintered ore in the total burden of the blast furnace;
when a blast furnaceWhen the ratio A of ore to iron is 1.66 and the ratio B of slag to iron of blast furnace is 0.35, the ratio Delta X isi≈4.743△YiC；
Obtaining CaF in blast furnace slag by using formula 12、Al2O3And increase amount of MgO: CaF2The increment of the iron slag is 0.16 to 0.36 percent by weight, has positive improvement effect on the fluidity of the blast furnace slag, is convenient for slag iron infiltration and separation, and is beneficial to the smooth production increase of the blast furnace. Al (Al)2O3Increase of (B) 0.35-0.91 wt%, Al2O3The content of the blast furnace slag is not more than 18wt%, and the melting temperature of the blast furnace slag is hardly influenced; to ensure the fluidity of the blast furnace slag iron, Al in the blast furnace slag2O3Is controlled in the range of less than 17 wt%; the amount of MgO added to blast furnace slag was: 0.12 to 0.34 weight percent, which is beneficial to improving the fluidity of the slag iron.
Due to Al2O3And CaF2The increase of the content and the proper increase of the alkalinity of the blast furnace slag are beneficial to keeping the enthalpy of the blast furnace slag and increasing the desulfurization effect, so that the binary alkalinity of the blast furnace slag is controlled to be 1.15-1.20, and the smooth operation and the desulfurization effect of the blast furnace are better.
The addition of LF refining slag to sintered ore results in S load increment of blast furnace of 0.012kg/t-0.060 kg/t. The S load is a professional term of iron making, generally refers to the total S content brought into a blast furnace by raw fuel required for producing 1t molten iron, and the S load of the blast furnace is about 4 kg/ton iron generally, so the influence of an increased amount on the S load can be ignored.
In S5, the slag iron after blast furnace smelting is discharged from a blast furnace taphole, the slag iron is separated by a skimmer, the blast furnace slag flows into a high-pressure water slag flushing channel through a slag channel and is quenched into small particles by high-pressure water to form a raw material of slag micro powder, so that zero emission of the blast furnace slag is realized, and zero emission of LF refining slag is realized.
When the blast furnace slag runner is overhauled or slag blockage cannot carry out normal slag flushing, high-temperature liquid blast furnace slag can be directly discharged to an accident slag pit, also called as slag of fire, and can be used as a production raw material of rock wool after being cooled, so that zero emission of the blast furnace slag is realized, and zero emission of LF refining slag is also realized.
Example 1
After the continuous casting furnace 01-1987 finishes casting, discharging LF refining slag out of a steel ladle by about 30wt%, cooling and crushing into powder, wherein the powder with the particle size of more than 3mm accounts for 4 wt%; the detection components are as follows according to the mass ratio: SiO 22：6%；CaO：60%；MgO：7%；Al2O3:15%；CaF2:8.0%；S:0.5%；
The pulverized LF refining slag is added into the sintered ore, and the proportion of the LF refining slag in the total ingredient amount of the sintered ore is 0.8 wt%; the detection result shows that the part indexes of the sintered ore in the embodiment are shown in the table 1:
table 1 example 1 sintered ore fraction index
| Index (I) | Binary basicity | Calcium fluoride content | Content of magnesium oxide | Aluminum oxide content | Tumbler index |
| Results | 1.80 | 0.11wt% | 2.55wt% | 1.99wt% | 78% |
| Increment of | 0.05wt% | 0.04wt% | 0.10wt% | 0.5% |
The sintered ore is added into a blast furnace, and the proportion of the sintered ore in the total amount of the blast furnace is 70 wt%; when the iron ratio A of the blast furnace is 1.66 and the iron ratio B of the blast furnace is 0.35, part of data in the blast furnace of the embodiment are shown in the following table 2:
TABLE 2 blast furnace slag part index and blast furnace utilization factor in example 1
| Index (I) | Binary basicity | Calcium fluoride content | Content of magnesium oxide | Aluminum oxide content | Blast furnace utilization factor |
| Results | 1.15 | 0.38wt% | 8.51wt% | 15.36wt% | 4.1 ton/(cubic meter. Tian) |
| Increment of | 0.17wt% | 0.13wt% | 0.33wt% | 0.1 ton/(cubic meter. day) |
After being separated by a skimmer, blast furnace slag and molten iron which are smelted by a blast furnace enter a slag sluiceway and a foundry ladle respectively, the blast furnace slag is used as a raw material for slag micro powder to be sold, and the molten iron enters steel making for blowing.
Example 2
After the casting of a 02-2057 furnace is finished, discharging about 35wt% of LF refining slag outside a steel ladle, cooling and crushing into powder, wherein the powder with the particle size of more than 3mm accounts for 3.5 wt%; the detection components are as follows according to the mass ratio: SiO 22：8%；CaO：55%；MgO：8.5%；Al2O3:18.5%；CaF2:6%；S:1.0%；
The pulverized LF refining slag is added into the sintering ore, the proportion of the LF refining slag in the total ingredient amount of the sintering ore is 1.0wt%, and through detection, part of indexes of the sintering ore in the embodiment are shown in a table 3:
table 3 example 2 sintered ore fraction index
| Index (I) | Binary basicity | Calcium fluoride content | Content of magnesium oxide | Aluminum oxide content | Tumbler index |
| Results | 1.91 | 0.13wt% | 2.58wt% | 2.07wt% | 79% |
| Increment of | 0.07wt% | 0.07wt% | 0.18wt% | 1.5% |
The sintered ore is added into a blast furnace, and the proportion of the sintered ore in the total amount of the blast furnace is 75 wt%; when the iron ratio A of the blast furnace is 1.66 and the iron ratio B of the blast furnace is 0.35, part of data in the blast furnace of the embodiment are shown in the table 4:
TABLE 4 example 2 blast furnace slag part index and blast furnace utilization factor
| Index (I) | Binary basicity | Calcium fluoride content | Content of magnesium oxide | Aluminum oxide content | Blast furnace utilization factor |
| Results | 1.18 | 0.46wt% | 8.63wt% | 15.67wt% | 4.05 ton/(cubic meter. day) |
| Increment of | 0.25wt% | 0.25wt% | 0.64wt% | 0.05 ton/(cubic meter. day) |
Blast furnace slag and molten iron are separated by a skimmer and then respectively enter a dry slag pit and a ladle for discharging fire slag, the blast furnace fire slag is cooled and then is used as a production raw material for producing rock wool, and the molten iron enters steel making for blowing.
Example 3
After the 02-2155 furnace is cast, discharging about 40wt% of LF refining slag from a steel ladle, cooling the discharged LF refining slag, and crushing the LF refining slag into powder, wherein the powder with the particle size of more than 3mm accounts for 3.0 wt%; the detection components are as follows according to the mass ratio: SiO 22：7%；CaO：50%；MgO：10%；Al2O3:22%；CaF2:7.0%；S:1.5%；
The pulverized LF refining slag is added into the sintered ore, the proportion of the LF refining slag in the total ingredient amount of the sintered ore is 1.2wt%, and through detection, part of indexes of the sintered ore in the embodiment are shown in Table 5:
table 5 example 3 sintered ore part index
| Index (I) | Binary basicity | Calcium fluoride content | Content of magnesium oxide | Aluminum oxide content | Tumbler index |
| Results | 2.00 | 0.16wt% | 2.60wt% | 2.13wt% | 78% |
| Increment of | 0.10wt% | 0.09wt% | 0.24wt% | 0.5% |
The sintered ore is added into a blast furnace, and the proportion of the sintered ore in the total ingredient amount of the blast furnace is 80 wt%; when the iron ratio A of the blast furnace ore is 1.66 and the iron ratio B of the blast furnace slag is 0.35, part of data in the blast furnace are shown in a table 6:
TABLE 6 example 3 blast furnace slag part index and blast furnace utilization factor
| Index (I) | Binary basicity | Calcium fluoride content | Content of magnesium oxide | Aluminum oxide content | Blast furnace utilization factor |
| Results | 1.20 | 0.59wt% | 8.72wt% | 15.94wt% | 4.1 ton/(cubic meter. Tian) |
| Increment of | 0.38wt% | 0.34wt% | 0.91wt% | 0.1 ton/(cubic meter. day) |
After being separated by a skimmer, blast furnace slag and molten iron which are smelted by a blast furnace enter a slag sluiceway and a foundry ladle respectively, the blast furnace slag is used as a raw material for slag micro powder to be sold, and the molten iron enters steel making for blowing.
Comparative example: after the casting of a 02-1923 furnace is finished, discharging about 40wt% of LF refining slag outside a steel ladle, cooling and crushing into powder, wherein the powder with the particle size of more than 3mm accounts for 3.0 wt%; the detection components are as follows: SiO 22：6.5%；CaO：56%；MgO：9%；Al2O3:18%；CaF2:6.5%；S:0.8%；
Through detection, the indexes of the sintered ore without the LF refining slag are shown in the table 7:
TABLE 7 partial indexes of comparative example sinter
| Index (I) | Binary basicity | Calcium fluoride content | Content of magnesium oxide | Aluminum oxide content | Tumbler index |
| Results | 1.95 | 0.06wt% | 2.51wt% | 1.89wt% | 77.5% |
The sintered ore is added into a blast furnace, and the proportion of the sintered ore to the total charge of the blast furnace is 73 wt%: the slag part index is shown in Table 8:
TABLE 8 comparative blast furnace slag part index and blast furnace utilization factor
| Index (I) | Binary basicity | Calcium fluoride content | Content of magnesium oxide | Aluminum oxide content | Blast furnace utilization factor |
| Results | 1.16 | 0.21wt% | 8.38wt% | 15.03wt% | 4.0 ton/(cubic meter. sky) |
After being separated by a skimmer, blast furnace slag and molten iron which are smelted by a blast furnace enter a slag sluiceway and a foundry ladle respectively, the blast furnace slag is used as a raw material for slag micro powder to be sold, and the molten iron enters steel making for blowing.
It can be seen from the above examples and comparative examples that the strength of the sintered ore is slightly improved after the LF refining slag is added to the sintered ore, and the utilization coefficient of the blast furnace is also slightly improved when the sintered ore added with the LF refining slag is added to the blast furnace for smelting, which indicates that the addition of the LF refining slag in the sintering and iron-making processes is beneficial to the strength of the sintered ore and the smooth degree of the blast furnace. The most important significance lies in that: under the premise of ensuring the strength of the sinter, the blast furnace slag can be recycled through water granulated slag and fire slag, zero emission is realized, and zero emission of LF refining slag is also realized.
Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that various changes in the embodiments and/or modifications of the invention can be made, and equivalents and modifications of some features of the invention can be made without departing from the spirit and scope of the invention.
Claims (4)
1. A method for realizing zero emission of refining slag of an LF furnace is characterized by comprising the following steps: the refining slag comprises 6 to 8 mass percent of SiO250-60% of CaO, 7-10% of MgO and 15-22% of Al2O36.0 to 8.0 percent of CaF20.5% -1.5% of S;
the method comprises the following steps:
s1, after the continuous casting molten steel is cast, discharging 30-40 wt% of LF refining slag in a ladle, and continuously recycling the rest of LF refining slag and the residual molten steel;
s2, cooling the discharged LF refining slag, and then crushing the slag into powder, wherein the proportion of the powder with the particle size of more than 3mm in the refining slag is required to be less than 5 wt%;
s3, adding a sinter raw material into the powdery LF refining slag; the proportion of LF refining slag in the sintered ore is 0.8wt% -1.2 wt%; CaF in sinter2Increase of 0.05wt% to 0.10wt%, Al2O3The increase of (A) is 0.10wt% to 0.24wt%, and the increase of MgO in the sintered ore is 0.04wt% to 0.09 wt%; controlling the binary alkalinity of the sintering ore added with the LF refining slag to be 1.8-2.0;
s4, adding the sintered ore into a blast furnace; blast furnace slagControlling the binary alkalinity at 1.15-1.20; al in blast furnace slag2O3Is controlled in the range of less than 17 wt%;
CaF in blast furnace slag2、Al2O3And the amount of increase in MgO are calculated as follows,
△X1=△X2AC/B
in the formula, Delta X1Is the increment of X component in the blast furnace slag,%;
△X2is the increase of X component in the sinter,%;
a is the iron-ore ratio of the blast furnace;
b is the slag-iron ratio of the blast furnace;
c is the proportion of the sintered ore in the total burden of the blast furnace;
the proportion of the sintered ore in the total burden amount of the blast furnace is 70-80 wt%;
s5, forming a raw material of slag micro powder after water quenching of blast furnace slag and forming a raw material for making rock wool by using blast furnace slag.
2. The method for realizing zero emission of the refining slag of the LF furnace as claimed in claim 1, wherein the sintered ore part indexes in S3 are as follows: CaF2The content is 0.11-0.16 wt%; MgO content of 2.55-2.60 wt%; al (Al)2O3The content is 1.99-2.13wt%, and the rotating drum index is 78-79%.
3. The method for realizing zero emission of the refining slag of the LF furnace as claimed in claim 1, wherein the method comprises the following steps: at S4, the CaF in the blast furnace slag2The content is 0.38-0.59 wt%; MgO content of 8.51-8.72 wt%; al (Al)2O3The content is 15.36-15.94 wt%; the utilization coefficient of the blast furnace is 4.05-4.1 tons/(cubic meter. day).
4. The method for realizing zero emission of the refining slag of the LF furnace as claimed in claim 1, wherein the method comprises the following steps: in S4, CaF in blast furnace slag2An increase of 0.17wt% to 0.38 wt%; the increase amount of MgO in the blast furnace slag is 0.13-0.34 wt%; al (Al)2O3The increase of (b) is 0.33wt% to 0.91 wt%.
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