CN103374640B - Method for smelting low-silicon molten iron in smelting reduction iron making process - Google Patents
Method for smelting low-silicon molten iron in smelting reduction iron making process Download PDFInfo
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- CN103374640B CN103374640B CN201210126512.3A CN201210126512A CN103374640B CN 103374640 B CN103374640 B CN 103374640B CN 201210126512 A CN201210126512 A CN 201210126512A CN 103374640 B CN103374640 B CN 103374640B
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Abstract
The invention relates to a method for smelting low-silicon molten iron in a smelting reduction iron making process. The method comprises the following steps of: blowing a certain amount of nitrogen into an air port of a melting gasification furnace so as to reduce the theoretical combustion temperature of the air port area and inhibiting the generation of SiO, meanwhile, adjusting the distribution indexes of coal and direct reduction iron, reducing the thickness of a cohesive zone, and shortening the time for silicon reduction and silicon entering molten iron; meanwhile, controlling the metallization ratio of the direct reduction iron, the temperature of molten iron, the specific value of CaO/SiO2 in slag and the content of Al2O3 in the slag in certain ranges. The method can be used for realizing the smelting of the low-silicon molten iron with low cost in the smelting reduction iron making process and does not increase the operation difficulty of smelting.
Description
Technical field
This relates to ironmaking technique of fusion and reduction, relates to a kind of method utilizing ironmaking technique of fusion and reduction smelting low-silicon molten iron specifically.
Background technology
Ironmaking technique of fusion and reduction is a kind of environmentally friendly non-blast furnace ironmaking technique, with the traditional blast furnace technology based on coking coal antithesis, it can directly use mill coal and natural lump ore and pelletizing to make crude fuel, produces the molten iron that blast furnace grade is suitable, is applicable to various steel-making purposes.
See Fig. 1, the ultimate principle of melting reduction iron-smelting method is: all metallurgical processing steps all complete in reduction shaft furnace 8 and melting gasification furnace 3 two independently reactor, the pure oxygen utilizing lump coal 4 and air port 1 to be blown into is at the heat of raceway 2, melting gasification furnace 3 bottom burning supply metallurgical process, lump coal 4 falls on the semicoke fixed bed of melting gasification furnace 3 top and completes coking, gasification, produce high-quality thermal reduction coal gas, this coal gas contains the CO+H of 85%
2with about 8% CO
2, first coal gas be adjusted to 800 ~ 850 DEG C of needs at generation gas line 6 after leaving melting gasification furnace, then after the thick dedusting of hot tornado dust collector 7, enter the reduction shaft furnace 8 on top.Iron ore pellets, lump ore 11 add from reduction shaft furnace 8 top, and be reduced into by the reducing gas from melting gasification furnace the sponge iron that degree of metalization reaches 50 ~ 80% in the process constantly declined in reduction shaft furnace 8, thermal sponge iron adds in melting gasification furnace 3 through spiral and downtake 5 continuously, fall on the semicoke fixed bed that formed after removing fugitive constituent by coal, further reduction, fusing, carburizing enter cupola well and form slag and molten iron, similar with blast furnace, also there are ladle heel layer, dead stock column and tuyere zone in melting gasification furnace.In order to the sulphur meeting the requirements of basicity of slag and remove in molten iron in melting gasification furnace 3, flux 4 needs to be added by reduction shaft furnace or be delivered directly to together with lump coal in melting gasification furnace 3 to carry out melting whole reduction.
From the principle of ironmaking technique of fusion and reduction, ironmaking technique of fusion and reduction can because the molten iron of the more difficult smelting low-silicon content of process characteristic of self.First ironmaking technique of fusion and reduction adopts pure oxygen air blast, its theoretical tuyere combustion temperature is up to about 3800 DEG C, far above the theoretical tuyere combustion temperature of about 2200 DEG C, traditional hot blast (oxygen enrichment) air blast blast furnace, the higher theoretical combustion temperature in region, air port can enter molten iron to Si reduction and play promoter action.Because according to the reduction mechanism of silicon, at the high temperature raceway zone of tuyere zone, SiO in coke ash
2with SiO contained in the slag flow down by dropping zone
2gaseous state SiO is reduced into by carbon.
(SiO
2)+C
(g)＝SiO
(g)+CO
(g) (1)
Gaseous state SiO rises with coal gas of high temperature, is then absorbed when running into the slag and iron liquid that are dripped by cohesive zone downwards at dropping zone, and simultaneously SiO is reduced by the saturated carbon during iron drips, and reaction product Si enters molten iron.
SiO
(g)+[C]＝[Si]+CO
(g) (2)
The higher theoretical combustion temperature in region, air port can make reaction (1) be strengthened, thus facilitates the reduction of silicon, and the silicone content in molten iron is raised.Secondly the fuel ratio of ironmaking technique of fusion and reduction is higher, and the about 1000Kg/tHM of fuel ratio of ironmaking technique of fusion and reduction, because the silicon in molten iron is mainly derived from fuel, therefore higher fuel ratio also can make the silicone content in molten iron raise.The Si content of melting and reducing molten iron is always higher, and in molten iron, silicone content higher meaning to need to consume amount of heat to reduce SiO in melting gasification furnace
2, fuel ratio is raised, and in addition, the molten iron after tapping a blast furnace need carry out the outer desiliconization process of stove, and cost can be caused to raise.Therefore for ironmaking technique of fusion and reduction, need to suppress this defect, in melting gasification furnace, make the silicone content in molten iron reduce in advance is very important.
Method at present about reducing molten iron silicon content in stove has following several:
(1) reduce molten iron temperature, this is a kind of fairly simple method, but this method exists increase operational risk, worsens the shortcomings such as the mobility of slag;
(2) Si oxide fine powder falls in tuyere injection, and a kind of method is jetted together with fine carbon powder by ferric oxide, and the high-temperature area before air port utilizes desilication reaction: [Si]+2 (FeO)=(SiO
2)+2Fe makes the Si in molten iron be oxidized, and reduces molten iron silicon content.Another kind method is jetted together with fine carbon powder by Mn breeze, and the high-temperature area before air port utilizes (MnO) and (FeO) to produce desilication reaction, and the Si in molten iron is oxidized, and reduces molten iron silicon content.In these methods, in order to oxide compound of jetting, ore grinding operation must be increased and set up equipment mineral fine being transported to air port, molten iron cost is raised;
(3) SiO is used
2the fuel that content is low, reduces into stove SiO
2amount, but SiO
2the fuel price that content is low is higher, and resource provision restriction is many;
(4) improve basicity of slag and control slag composition etc.
The method also having some to reduce molten iron silicon content falls silicon method conbined usage by several, Chinese patent CN03802274.5 open " manufacture method of hot metal containing low silicon ", which describe a kind of method manufacturing hot metal containing low silicon, by the fine carbon powder utilizing winding-up more than molten iron 150kg per ton, and the MgO of control blast-furnace slag is 5.5 ~ 8.5%, the method for Si below 0.3% controlling molten iron is formed.But this method needs higher injecting coal quantity, for the ironmaking technique of fusion and reduction of or not coal powder injection low for injecting coal quantity, feasibility is lower.
Summary of the invention
The object of the invention is a kind of method providing ironmaking technique of fusion and reduction smelting low-silicon molten iron, simple to operate, economically feasible, namely a certain amount of nitrogen is blasted to air port, for reducing tuyere zone domain theory temperature of combustion, suppress the generation of SiO gas, adjust the cloth index of coal and direct-reduced iron simultaneously, shorten cohesive zone thickness, reduce the time that Si reduction enters molten iron, in ironmaking technique of fusion and reduction, finally realize low cost smelting low-silicon molten iron, and do not increase the operation easier of smelting.
For achieving the above object, technical scheme of the present invention is:
A method for deoxy iron-smelting technique smelting low-silicon molten iron, adopts and blasts nitrogen to melting gasification furnace air port, namely on the oxygen house steward of air port, installs nitrogen pipeline, and in the nitrogen oxygen mixed gas that air port is blown into, the volume ratio of nitrogen is 2% ~ 15%; Block Coal and coke by coal distributor cloth to melting gasification furnace charge level, through the direct-reduced iron of shaft furnace prereduction and coke by direct-reduced iron turnover panel cloth to melting gasification furnace charge level, according at the relative height of each gear cloth and the cloth index of gear radius calculation coal and direct-reduced iron, cloth formula of index is:
Cloth index=∑ every grade relative height × every grade of radius
Wherein, the available gear radius of coal distributor and direct-reduced iron turnover panel is 0m, 0.5m, 1m, 1.5m, 2m, 2.5m, 3m, 3.5m, 4m, 4.5m, 5m, and gear radius is the distance of the material drop point distance same level face stove heart; Coal cloth index span of control is 4 ~ 9, direct-reduced iron cloth index span of control is 8 ~ 12, by coal distributor cloth to melting gasification furnace charge level coke be 1/5 ~ 1/3 by direct-reduced iron turnover panel cloth to the weight ratio of the coke of vapourizing furnace charge level, shorten cohesive zone thickness with this, reduce the time that Si reduction enters molten iron.
Further, the degree of metalization of direct-reduced iron controls more than 50%, and preferably 60% ~ 80%, to reduce the usage quantity of fuel.
Again, molten iron temperature controls at 1480 DEG C ~ 1520 DEG C.
CaO/SiO in slag
2control 1.15 ~ 1.25, Al in slag
2o
3weight percent controls 12 ~ 17%.
In addition, nitrogen pipeline of the present invention is divided into supervisor and arm, and nitrogen supervisor arranges the first stopping valve and the first variable valve, and main conduit flow's span of control is 0-10000Nm
3; Nitrogen arm arranges the second stopping valve and the second variable valve, and arm flow control scope is 0-5000Nm
3, when normally producing, close the first stopping valve on nitrogen supervisor and the first variable valve, in the nitrogen oxygen mixed gas be blown into according to air port, the ratio setpoint of nitrogen is to control the aperture of the second variable valve on nitrogen arm, then opens the second stopping valve; When damping down or multiple wind need a large amount of nitrogen, first, second variable valve is set to maximum value, then opens first, second stopping valve.
According to the mechanism of Si reduction in iron manufacturing process, the reduction of silicon, mainly by two reaction controlling, namely occurs in the reaction (1) in region, air port and the reaction (2) of soft melting dropping band:
(SiO
2)+C
(g)＝SiO
(g)+CO
(g) (1)
SiO
(g)+[C]＝[Si]+CO
(g) (2)
Based on this understanding, for reducing the silicone content in molten iron, the present invention generates from suppression gaseous state SiO and suppresses SiO-Si to shift two aspects and starts with.Namely control the reaction conditions relevant with (2) with reaction (1) and suppress Si reduction.
First blast a certain amount of nitrogen to melting gasification furnace air port, for reducing tuyere zone domain theory temperature of combustion, thus the temperature of reaction of reaction (1) is reduced, suppress the generation of SiO gas.Meanwhile by adjusting the cloth index of vapourizing furnace lump coal and direct-reduced iron, shorten soft melting dropping tape thickness, coal gas containing SiO gas is passed through more quickly react the region of (2), thus shorten the reaction times of reaction (2), finally obtain the molten iron that silicone content is lower.
In addition, the present invention is in order to reduce molten iron silicon content from reducing into aspects such as stove silicon total amount, promotion cupola well silicon oxidation and suppression cupola well Si reductions, the degree of metalization of direct-reduced iron is controlled more than 50%, preferably 60% ~ 80% (degree of metalization is higher, the fuel that vapourizing furnace needs is fewer, the silicon total amount of being brought into vapourizing furnace by fuel is lower), molten iron temperature controls at 1480 DEG C ~ 1520 DEG C, the CaO/SiO in slag
2control 1.15 ~ 1.25.
Beneficial effect of the present invention:
1. can not increase operational risk, when worsening the mobility of slag, reduce molten iron silicon content, improve molten steel quality.
2. can avoid carrying out the outer desiliconization process of stove to the molten iron after tapping a blast furnace, thus reduce smelting cost.
3. a certain amount of nitrogen of tuyere injection reduces theoretical tuyere combustion temperature, not only can suppress the reduction of silicon, can also play the effect in protection air port, reduces the damaged number in air port.
4. the present invention not only can reduce molten iron silicon content when not increasing operational risk, improves molten steel quality, and can protect air port, reduces the damaged number in air port.
5. the present invention both can implement on ironmaking technique of fusion and reduction, and can be generalized to again on the iron-smelting process of all employing pure oxygens air blast, popularizing application prospect is extremely wide.
Accompanying drawing explanation
Fig. 1 is ironmaking technique of fusion and reduction schematic diagram of the present invention.
Wherein, 1-air port; 2-raceway zone; 3-melting gasification furnace; 4-lump coal, coke, flux; 5-direct-reduced iron downtake; There is gas pipe in 6-; The hot whirlwind of 7-; 8-reduction shaft furnace; 9-reducing gas; The superfluous coal gas of 10-; 11-iron ore, coke, flux; 12-pushes up coal gas.
Fig. 2 is the structural representation that nitrogen is added in air port of the present invention.
Wherein, 13-oxygen house steward; 14-nitrogen pipeline, 141-nitrogen is responsible for, 142-nitrogen arm; 17,17 '-first, second stopping valve; 18,18 '-first, second variable valve; 19-oxygen house steward stopping valve, 19 '-oxygen house steward variable valve.
Fig. 3 is distributing mode schematic diagram of the present invention.
Wherein, 1-air port; 3-melting gasification furnace; 15-coal distributor; 16-direct-reduced iron turnover panel; The dead stock column of 20-; 21-cohesive zone; 22-molten iron; 23-coal; 24-direct-reduced iron.
Embodiment
Below in conjunction with embodiment and accompanying drawing, the present invention will be further described.
See Fig. 1 ~ Fig. 3, the method of a kind of deoxy iron-smelting technique smelting low-silicon molten iron of the present invention, adopt and blast nitrogen to melting gasification furnace air port 1, namely on air port oxygen house steward 13, install nitrogen pipeline 14, in the nitrogen oxygen mixed gas that air port is blown into, the volume ratio of nitrogen is 2% ~ 15%; Block Coal and coke A by coal distributor 15 cloth to melting gasification furnace 3 charge level, through the direct-reduced iron of shaft furnace 8 prereduction and coke B by direct-reduced iron turnover panel 16 cloth to melting gasification furnace 3 charge level, according at the relative height of each gear cloth and the cloth index of gear radius calculation coal and direct-reduced iron, cloth formula of index is:
Cloth index=∑ every grade relative height × every grade of radius
Wherein, the available gear radius of coal distributor 15 and direct-reduced iron turnover panel 16 is 0m, 0.5m, 1m, 1.5m, 2m, 2.5m, 3m, 3.5m, 4m, 4.5m, 5m, and gear radius is the distance of the material drop point distance same level face stove heart; Coal cloth index span of control is 4 ~ 9, and direct-reduced iron cloth index span of control is 8 ~ 12, by coal distributor cloth to melting gasification furnace charge level coke A be 1/5 ~ 1/3 by direct-reduced iron turnover panel cloth to the weight ratio of the coke B of vapourizing furnace charge level.
Further, the degree of metalization of direct-reduced iron controls more than 50%, and preferably 60% ~ 80%, to reduce the usage quantity of fuel.
Molten iron temperature controls at 1480 DEG C ~ 1520 DEG C.CaO/SiO in slag
2control 1.15 ~ 1.25, Al in slag
2o
3weight percent controls 12 ~ 17%.
See Fig. 2, described nitrogen pipeline 14 is divided into nitrogen to be responsible for 141 and nitrogen arm 142, and nitrogen supervisor 141 arranges the first stopping valve 17 and the first variable valve 18, and main conduit flow's span of control is 0-10000Nm
3; Nitrogen arm 142 arranges the second stopping valve 17 ' and the second variable valve 18 ', and arm flow control scope is 0-5000Nm
3during normal production, close the first stopping valve 17 and the first variable valve 18 on nitrogen supervisor 141, in the nitrogen oxygen mixed gas be blown into according to air port, the ratio setpoint of nitrogen is to control the aperture of the second variable valve 18 ' on nitrogen arm 142, then opens the second stopping valve 17 '; When damping down or multiple wind need a large amount of nitrogen, first, second variable valve 18,18 ' is set to maximum value, then opens first, second stopping valve 17,17 '.
The Operating parameters setting of the embodiment of the present invention and contrast benchmark is as shown in table 1:
Table 1
Table 2 test-results
| Molten iron Si content, % | Operational stability | Slag fluidity | |
| Contrast benchmark | 0.80 | Stable | Good |
| Embodiment 1 | 0.40 | Stable | Good |
| Embodiment 2 | 0.50 | Stable | Good |
| Embodiment 3 | 0.30 | Stable | Good |
| Embodiment 4 | 0.40 | Stable | Good |
| Embodiment 5 | 0.35 | Stable | Good |
According to the test-results of Operating parameters listed by table 1 in table 2.
After adopting method of the present invention, molten iron Si content can reduce by 37.5% ~ 62.5%, and the stability of operation and the mobility of slag are obtained for good maintenance.
Claims (4)
1. a method for deoxy iron-smelting technique smelting low-silicon molten iron, adopts and blasts nitrogen to melting gasification furnace air port, namely on the oxygen house steward of air port, installs nitrogen pipeline, and in the nitrogen oxygen mixed gas that air port is blown into, the volume ratio of nitrogen is 2% ~ 15%; Block Coal and coke by coal distributor cloth to melting gasification furnace charge level, through the direct-reduced iron of shaft furnace prereduction and coke by direct-reduced iron turnover panel cloth to melting gasification furnace charge level, according at the relative height of each gear cloth and the cloth index of gear radius calculation coal and direct-reduced iron, cloth formula of index is:
Cloth index=∑ every grade relative height × every grade of radius
Wherein, the available gear radius of coal distributor and direct-reduced iron turnover panel is 0 ~ 5m, and gear radius is the distance of the material drop point distance same level face stove heart; Coal cloth index span of control is 4 ~ 9, and direct-reduced iron cloth index span of control is 8 ~ 12, by coal distributor cloth to melting gasification furnace charge level coke be 1/5 ~ 1/3 by direct-reduced iron turnover panel cloth to the weight ratio of the coke of vapourizing furnace charge level; Wherein, the degree of metalization of direct-reduced iron controls more than 50%; Molten iron temperature controls at 1480 DEG C ~ 1520 DEG C; CaO/SiO in slag
2control 1.15 ~ 1.25, Al in slag
2o
3weight percent controls 12 ~ 17%.
2. the method for deoxy iron-smelting technique smelting low-silicon molten iron as claimed in claim 1, is characterized in that: the degree of metalization of direct-reduced iron controls 60% ~ 80%.
3. the method for deoxy iron-smelting technique smelting low-silicon molten iron as claimed in claim 1, is characterized in that: described gear radius is 0m, 0.5m, 1m, 1.5m, 2m, 2.5m, 3m, 3.5m, 4m, 4.5m, 5m.
4. the method for deoxy iron-smelting technique smelting low-silicon molten iron as claimed in claim 1, is characterized in that: described nitrogen pipeline is divided into supervisor and arm, nitrogen supervisor arranges the first stopping valve and the first variable valve, and main conduit flow's span of control is 0-10000Nm
3; Nitrogen arm arranges the second stopping valve and the second variable valve, and arm flow control scope is 0-5000Nm
3, when normally producing, close the first stopping valve on nitrogen supervisor and the first variable valve, in the nitrogen oxygen mixed gas be blown into according to air port, the ratio setpoint of nitrogen is to control the aperture of the second variable valve on nitrogen arm, then opens the second stopping valve; When damping down or multiple wind need a large amount of nitrogen, first, second variable valve is set to maximum value, then opens first, second stopping valve.
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|---|---|---|---|
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|---|---|---|---|
| CN201210126512.3A CN103374640B (en) | 2012-04-26 | 2012-04-26 | Method for smelting low-silicon molten iron in smelting reduction iron making process |
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| CN115679028B (en) * | 2022-09-16 | 2023-07-04 | 新疆八一钢铁股份有限公司 | Low-silicon smelting method of European smelting furnace |
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Effective date of registration: 20200622 Address after: 830022 No. 1 Bayi Road, Toutun River District, the Xinjiang Uygur Autonomous Region, Urumqi Patentee after: XINJIANG BAYI IRON & STEEL Co.,Ltd. Address before: 200122 No. 370 Pu circuit, Shanghai, Pudong New Area Patentee before: BAOSTEEL Group Corp. |