CN1043061C - Method for directly smelting stainless steel by chromium ore fusion reduction - Google Patents
Method for directly smelting stainless steel by chromium ore fusion reduction Download PDFInfo
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- CN1043061C CN1043061C CN95111781A CN95111781A CN1043061C CN 1043061 C CN1043061 C CN 1043061C CN 95111781 A CN95111781 A CN 95111781A CN 95111781 A CN95111781 A CN 95111781A CN 1043061 C CN1043061 C CN 1043061C
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Abstract
The present invention relates to a method for directly smelting stainless steel by melting and reducing chromium ore in a top and bottom combined blowing converter. When chromium ore is molten and reduced, a three-layer compound top gun with double flow channels respectively blows inert airflow, primary combustion oxygen flow and secondary combustion oxygen flow to slag from bottom to top, the primary combustion oxygen flow and the secondary combustion oxygen flow are used for agitating and heating the slag, chromium as a raw material is heated with high efficiency, and the inert airflow impacts a metal surge formed by agitation of bottom blowing inert gas; carbon in metal liquid droplets above the metal surge is dispersed to the converter wall, the carbon is fully agitated and mixed with carbon containing agglomerate enriched on the converter wall, and thus, the chromium reduction is promoted. After the melting process and the reduction are completed, the same top gun blows decarbonizing oxygen diluted by inert gas into the converter, high-chromium molten iron is converted, and simultaneously, the bottom blowing inert gas is violently agitated.
Description
The present invention relates to by chrome ore or/and NiO utilizes the method for the direct smelting stainless steel of combined blown converter.
Chromium always or chromium nickel stainless steel are with the ferrochrome of being smelted by chrome ore or/and nickel is raw material smelts once more and form.Different therewith is that from energy-conservation, reduction smelting cost, the smelting reduction process of ferronickel water has obtained success or/and the oxide raw material of nickel directly obtains chromium by chrome ore recently.This method by with chrome ore or/and the oxide compound of nickel and carbonaceous material and oxygen are sent into iron bathes in the reactor, with Cr or/and the oxide compound of Ni directly reduce, make saturated carbon containing, chromium or/and the nickel composition near the Fe-Cr of stainless steel requirement or/and Ni liquid is mother liquor, and then smelting stainless steel.
At present, the melting and reducing of chrome ore had proposed several modes, and representative in advance is the oxygen blown iron-bath process of top blowing oxygen, bottom blowing and side of clear 61-279608 patent, because it gets involved the reduction zone with oxygen, made that this method speed of response is slow, and productivity is low; Thereafter top and bottom complex blowing iron-bath process, the secondary combustion zone is placed slag blanket top, heat is passed to metal pool by gas phase and slag blanket, the raising post-combustion rate can make spent air temperture rise so high and take away a large amount of heat, thereby do not have the matching problem of fine solution post-combustion rate and thermo-efficiency, it is low-level to make that productivity still is in; The open CN89103396.3 of patent application notices the shortcoming of above method, adopted the method for top blast, bottom blowing, side-blown, chrome ore is carried out melting and reducing, this technology adopts the fusion reducing furnace that has bottom blowing air port, side-blown air port and top blow oxygen lance, directly add chrome ore, carbonaceous material from fire door, utilize the Cr materials such as carbon reduction chrome ore of carbonaceous material, obtain high chromium hot melt after, on same stove, high chromium hot melt carried out the decarburization blowing.
When melting and reducing, carry out being blown into of following gas:
(1) is blown into CO or/and rare gas element from the bottom blowing air port
(2) be blown into CO or/and rare gas element, the metal bump part that a part of gas shock is caused by bottom blown gas from the side-blown air port.
(3) to molten metal, be blown into decarburization O from the top rifle
2, in slag, be blown into secondary combustion O simultaneously
2
Its characteristics are, utilize side-blown gas to impact the metal bump part that is caused by bottom blown gas, molten drop is splashed enter slag blanket, and the chromated oxide in the contact reducing chrome ore stone, the top rifle infeeds decarburization O to molten metal on the one hand
2, the heated and stirred molten metal is blown into secondary combustion O on the other hand in slag
2, keep post-combustion rate more than 0.3, the reduction processing finishes the back deslagging, then is blown into decarburization O with inert gas dilution from the top rifle to high Cr molten iron
2, be blown into rare gas element violent stirring molten iron simultaneously from the bottom blowing air port, carry out the decarburization blowing, finally obtain qualified molten steel, obviously there is following deficiency in the CN89103396.3 method:
(1) during smelting reduction, directly is blown into decarburization oxygen the metal pool, causes the re-oxidation of chromium in the molten metal, carbon, reduced melting and reducing speed from the top rifle.
(2) the side-blown air port from stationkeeping is blown into rare gas element impact molten metal ridge, though can when slag one metal bath surface arrives a certain height, bring into play certain effect, but can not omnidistance optimum matching, and side-blown air port itself certainly leads to negative influence to body of heater, the minimizing converter life.
The object of the invention just provides a kind of have higher melting and reducing speed and good decarburization effect, and more the become method of the direct smelting stainless steel of rational melting and reducing of equipment, this method improves rate of reduction and converter life and has obtained satisfied effect preventing the re-oxidation of C, Cr.
Metallurgy principle shows: the slag zone is the main zone of melting and reducing.In fact, the melting and reducing production intensity is decided by four big reduction reaction key elements: oxide compound---the intermetallic phase contact area of charcoal---reducing gas---.Not hard to imagine, because action of gravity, the position of the maximum that this interfacial area exists is not furnace gas district and molten metal phase region, but slag phase region between the two.The data that record are simply calculated promptly provable, the phase interface in the slag phase region is distinguished high two more than the order of magnitude than other, under the prerequisite that the heat energy supply is protected, about this multiplying power productivity.When ore, C material enters after slag is bathed in the stove, though cracked, fusing and direct reaction and the situation about diminishing of material in the high-temperature slag district can occur, very fast balance is: the upper strata mainly contains O
2, CO, CmHn, N
2Deng than air pocket and big grain C material, lower floor mainly contains CO, N
2Deng distribution situation than small bubbles, mineral aggregate, the saturated molten drop of C and granule C material.As seen, the upper strata has possessed the condition of C material oxidation heating, and lower floor has then possessed the small-particle mineral aggregate by the saturated molten metal of C, C material, CO bubble reductive condition.The mode that mineral aggregate is reduced in slag can be divided into two classes:
1, the oxide compound that is dissolved in the slag is contained C drop, C material, the reduction of CO bubble;
2, not molten oxide compound is contained C drop, C material, the reduction of CO bubble.
The speed of the 1st class reaction obviously is subjected to the domination of dissolution rate, it is subjected to the restriction of temperature and slag ingredient, and temperature and slag ingredient can not be selected on a large scale, so the reduction rate of this class reaction can not wide variation, about about 0.1~0.2 (%Cr)/min, thereby to continue to improve speed of response and must develop the 2nd class reaction.
Further analyze slag and bathe the reduction reaction district, the saturated iron drop of C under the thrust in the bottom blowing be present in that metal that the bottom blowing air-flow causes gushes more above, but because of proportion is difficult for greatly being brought to from gushing at a distance by slag stream, mineral aggregate is then gushed co-axial slag with metal and gushes and be pushed into from gushing place far away in slow sinking process.Thereby along continuous straight runs has the trend that forms molten drop compact district and mineral aggregate enrichment region again, obviously, gives an external force again, and two districts are mixed, and can improve the speed of the 2nd class reaction.Because the interface of this two districts reaction mass accounts for the overwhelming majority at total reaction interface, this mixing plays an important role to improving speed of reaction.Aborning, along with the increase that adds ore deposit speed, the speed of the 1st class reaction is the limit gradually, has only the reaction of development the 2nd class, just gets so that speed of response continues to increase substantially, and reaches the purpose of fast restore.
After reduction rate improves, must have high heat supply speed to match, method is:
1, improves the post-combustion rate of C.Can solve by the measure of secondary combustion with oxygen;
2, improve C incendiary heat transfer efficiencies.Can move down and strengthen the stirring solution of slag by the secondary combustion zone.
In addition, because the proportion of charcoal material is less than slag, and any reaction of C in slag all be nuclear with C, produces bubble, forms C---bubble stabilizes polymer, and its proportion is much smaller than slag, and therefore, charcoal has the serious tendency that breaks away from the reduction zone.For this reason, breeze and powdered carbon are bonded into agglomerate go into stove, charcoal promptly sinks to slag phase lower floor reduction zone with agglomerate, make the bottom have competent C source to participate in slag and bathe reaction, and smoothly to metal bath for C, keep the saturated of C.In addition, contain the charcoal agglomerate and in melting process, also have a certain proportion of autoreduction.
To mother liquor of stainless steel take off the C refining, existing big quantity research has formed numerous methods.It is to reduce the Pco that takes off the C reaction that the most effective C of taking off protects the Cr means.In the most easy measure of antivacuum reduction Pco down be:
1, the upper surface at metal pool takes off C, makes ferrostatic pressure be reduced to zero; Reduce the forming core merit of CO bubble;
2, at O
2When jet and metallic contact, the contact position produces a large amount of CO, and the Pco of this place is increased severely, and is unfavorable for taking off the C reaction.With inert gas dilution O
2Stream then can reduce the Pco value significantly.
For reaching melting and reducing chrome ore purpose, the present invention adopts the top and bottom combined blown converter with bottom blowing air port and top rifle, by carbon-bearing lump in the adding stove and/or the chromium in the carbon source reducing chrome ore stone in the carbonaceous material, after obtaining high chromium hot melt, in same converter, saturated carbonaceous high chromium hot melt is carried out Decarburising and refining, finally make qualified stainless steel.
During smelting reduction, blow N from the bottom blowing air port
2Or/and rare gas element, in stove, add carbonaceous material and chrome ore or/and the carbon containing mineral aggregate from fire door, near three layers of compound top of the double flow duct from imbed slag or metal bath surface rifle is blown into N from bottom to top respectively to the in-furnace slag layer simultaneously
2Or/and rare gas element, primary combustion after the melting and reducing end, carry out deslagging with oxygen, secondary combustion oxygen, then be blown into N from the bottom blowing air port
2Or/and the stirring of inert gas molten bath then is blown into N from the bottom blowing air port
2Or/and the stirring of inert gas molten bath, three layers of compound top of double flow duct rifle is blown into the decarburization of inert gas dilution to high Cr molten iron and carries out the decarburization blowing with oxygen.
Key points for operation are as follows:
During smelting reduction:
(1) be blown into nitrogen from the bottom blowing air port or/and inert protective gas, agitation molten pool, the metal that forms protuberance at metal bath surface gushes.
(2) be blown into nitrogen at a certain angle or/and rare gas element (1a) from the top rifle to stove inner metal liquid face, according to the quantity that adds mineral aggregate in the stove, calculate the height of molten metal, make muzzle and molten metal keep constant distance substantially, the impact metal gushes, push intensive molten drop in the metal side of swarming to furnace wall mineral aggregate enrichment region, the two thorough mixing makes the chromium in the carbon source fast restore chrome ore in the molten drop.
(3) tiltedly blow a combustion oxygen flow (1b) from the top rifle to in-furnace slag lower floor, with the carbon-bearing lump that enters slag lower floor or/and the carbon burning in the carbonaceous material, and the stirring action by the furnace bottom rare gas element, rapid heating metal pool.Reduced the re-oxidation of metal simultaneously.
(4) from the top rifle to the in-furnace slag upper strata be bordering on flatly be blown into two the combustion oxygen flows (1c), fully burn on the slag upper strata, generate heat in slag, and efficiently stir slag.
(5) carbon-bearing lump that adds in stove is the pellet that breeze and carbon dust are bonded into, and its carbon content is 10~25%, because its proportion is greater than slag, major part enters slag lower floor, makes slag lower floor reduction zone have enough carbon sources to participate in slag and bathes reaction.Carbon in the pellet is used for the autoreduction of nodulizing except part, and a part participates in the primary combustion heat supply, a part then smoothly to metal pool for carbon, unreduced mineral aggregate is then owing to the stirring action of bottom blown gas is enriched in around the furnace wall.
(6) according to chemical reaction in top rifle air supply intensity, gas shock metal pool intensity and the stove, the tone level that adopts detector to collect changes, determine slag foaming height and slag height, regulate the top rifle and make slag foaming height maximum that control adds ore deposit speed to maximum extremely near the fire door position.If slag foaming height is big (overflowing fire door) too, can suitably in stove, add carbon dust, weaken bubble level.
(7) use CO
2The successive analysis instrument is measured CO in the stove
2Concentration, control rifle position keeps post-combustion rate more than 0.4.
(8) the bottom blowing air port is 2~4, and being evenly distributed in the top rifle is on the circumference at the center of circle, burner hearth radius 1/2~1/3 place.
(9) after melting and reducing finishes, carry out deslagging, enter the Decarburising and refining phase.
During the decarburization blowing.
(10) be blown into N from the bottom blowing air port
2Or/and stirring of inert gas metal pool.
(11) be blown into the decarburization oxygen of using inert gas dilution from the top rifle to high Cr molten iron, the carrying out along with the decarburization blowing increases the N in the top-blown gas gradually
2Or/and rare gas element (2a) ratio reduces decarburization with oxygen (2b) amount,, reach the good C that takes off and protect the Cr effect to reduce Pco value in the stove.
(12) top blast takes off N in the C gas
2And/or the ratio of rare gas element (2a) and oxygen (2b) changes, and adopts the computer continuous stepless to regulate, and takes off the C effect, avoids the re-oxidation of Cr with raising.
The present invention compares with the open CN89103396.3 of patent application, has following advantage:
(1) the top and bottom combined blown converter furnace lining need not change, and the body of heater of having avoided side-blown air port, furnace wall to bring is safeguarded and lost of life problem.
(2) mineral aggregate adds the molten bath with the form that contains the C nodulizing, not only guarantees the part autoreduction reaction of nodulizing, the more important thing is the carbon source that has increased slag lower floor reduction zone, helps the raising of rate of reduction.
(3) the top rifle gushes at the metal that is formed by bottom blowing microgas body and is blown into small amount of N
2/ or rare gas element (1a), the molten drop that promotes the metal side of swarming stirs with the mineral aggregate thorough mixing that is enriched in the furnace wall, has improved reduction reaction rate greatly.
(4) adopt the slag proofing unit,, regulate top rifle height, make the slag foaming height maximization, accelerated to add ore deposit speed, improved rate of reduction greatly according to the variation of tone level.
The oxygen supply mode of (5) tiltedly blowing has reduced oxygen to the metal pool effect, the adverse effect of metallic element re-oxidation when having avoided smelting reduction.
(6) the top rifle buries the flame heating, and adopts CO
2The analyser automatic monitor for continuously has further improved post-combustion rate and heating efficiency.
When (7) taking off the C refining, the C district of taking off that decarburization oxygen flow (2b) arrives is positioned at the top layer, molten bath, and through top, bottom blowing N
2And/or the stirring of inert gas effect, make this district have the feature of high reaction interface, low CO dividing potential drop, low forming core merit, thus constitute the high strength oxygen supply efficiently take off C district, take off the C reaction on average to 0.2 (%C)/min, Cr oxidational losses<0.5%, the tool equipment is simply.
(8) computer stepless continuous control N
2(Ar) with) its O
2Blending ratio, make the whole C of taking off process stabilization, the oxidational losses of chromium≤0.5%.
Description of drawings:
Fig. 1 is a process flow diagram of the present invention
Fig. 2 is a melting and reducing phase process schematic representation of the present invention
Fig. 3 is a decarburization blowing process process schematic representation of the present invention
Fig. 4 is tone level instrument control slag figure of the present invention
Fig. 5 is a bottom blowing air port synoptic diagram
Embodiment:
Certain steelworks is implemented the present invention, and in the top and bottom combined blown converter of 15 tons of nominal capacities, melting and reducing Cr ore is directly smelted the OCr13 stainless steel, and concrete technological operation is as follows:
1, upwards the stove tapping stay contain Cr
xO
yBe blended into during slag is bathed and take off the P molten iron, add the C material.
2, be the center from being evenly distributed in the top rifle, 4 the bottom blowing air ports bottom blowing N in stove on the circumference at burner hearth radius 1/3 place
2And/or stirring of inert gas molten iron.
3, three layers of compound top of double flow duct rifle blows N
2Stirring, heating by O2 blowing make Cr
xO
yReduction rapidly, molten iron heats up rapidly.
4, nearly 1600 ℃ of bath temperature, (Cr
xO
y)<4% o'clock, beginning (or short run is continuous) continuously drop in stove and contain C nodulizing and charcoal material.Carbon-bearing pellet is the low strength pellet that carbon dust and breeze are bonded into, and its carbon content is 10~25%, and the charcoal material is coal, nut coke etc., and except that P, S have the requirement, kind is not limit, and adding speed and mineral aggregate are synchronous, and its quantity is the combustion heating consumption and goes back Cr in the reduced ore
xO
y, Fe
xO
yThe equivalent value sum, and to make slag bathe suspension C amount all the time be 15~25%.
5, adopt the slag proofing unit,, regulate top gun gun bit, make in-furnace slag bubble level maximum, (, can add a small amount of powdered carbon and suppress) if sinter thickness is too high to the fire door position according to the variation of its tone level signal.Control adds ore deposit speed to maximum, boosts productivity, and the total amount of calculating by 95% recovery rate until mineral aggregate adds.
6, rifle top-blown gas in stove in three layers of compound top of double flow duct is blown into N from bottom to top respectively along level height in slag
2Or/and rare gas element (1a), primary combustion are with oxygen (1b) and secondary combustion O
2(1c)
7, carbon-bearing pellet since its than great sub-slag, mostly sink to slag lower floor, and be cracked into little mineral aggregate.Except the part autoreduction, part C source and top rifle tiltedly are blown into the primary combustion of slag lower floor and heat with oxygen (1b) burning, part C source enters metal pool smoothly, increased the reduction potential of slag lower floor reduction zone, unreduced mineral aggregate is because the stirring action of top and bottom complex blowing is enriched in the furnace wall inwall.
8, according to the mineral aggregate quantity measuring and calculating molten metal height that adds in the stove, regulate top rifle and metal bath surface and keep certain distance, make the top rifle be bordering on the N of side-blown
2(1a) impact the metal that forms by bottom blowing microgas body and gush, and the molten drop that promotes the metal side of swarming makes the C source in the molten drop stir acceleration Cr with the mineral aggregate thorough mixing that is enriched in inboard wall of burner hearth to the disperse of inboard wall of burner hearth direction
xO
yIn Cr reduction.
9, the top rifle is to slag upper strata side-blown secondary combustion O
2(1c), efficiently stir and generate heat, adopt CO simultaneously in slag
2Analyser METHOD FOR CONTINUOUS DETERMINATION CO
2Concentration, control top rifle reaches more than 0.4 post-combustion rate, guarantees heat supply intensity.Make bath temperature be stabilized in 1500~1650 ℃.
10, after all mineral aggregate adds, continue oxygen blast and stir, enter whole reduction.For strengthening reduction rate, except that can adding the C material, also can add other reductive agent, as Fe-Si, SiC etc.
11, processing parameter span of control
Stirring N
2: 0.3~0.8Nm
3/ min.t (t is the terminal point amount of metal, down together) top blast oxygen supply intensity: 4.5~6.0Nm
3/ min.t
Basicity of slag: CaO%/SiO2%=1~2.5
12, treat that Cr reduces to below 1% in the slag, can remove the gred
13, remove the gred to part metals exposed after, with above-mentioned same top rifle high Cr molten iron is taken off the C refining.
When 14, taking off the C blowing, be blown into N from the bottom blowing air port
2Or/and the stirring of inert gas molten bath, air supply intensity is not done big variation, and the top rifle is reduced in the stove simultaneously, is blown into and uses N
2Or/and the O of inert gas dilution
2High Cr molten iron is taken off the C blowing.
15, the top rifle is blown into N respectively in stove
2Or/and inert gas (2a), take off C oxygen flow (2b) and two combustion oxygen flows (2c), at this moment, air- flow 2a, 2b are not imbedding under the condition of slag, partly mix, and form very low Pco with (C) reaction back.Owing to be in the position of nearly molten metal after inert gas (2a) ejection, need lesser amt just can will take off C O
2Dilution.Because this bubble just in time acts on the molten drop compact district, reaction interface is big, speed is fast, easily reaches lower C-O equilibrium value.The CO that is produced rises, and with two combustion oxygen flow (2c) reactions, has improved temperature in the stove greatly.This temperature makes again takes off easier the carrying out of C reaction, forms benign cycle.
16, above process reaction speed is fast, and the oxygen utilization rate height can adopt big flow oxygen supply, and oxygen supply intensity reaches as high as 4.5Nm
3/ min.t.Along with the decline oxygen supply intensity of (C) is progressively reduced to 1Nm
3/ min.t, meanwhile, inert gas flow progressively increases, and is up to 3Nm
3/ min.t, gas are progressively by N
2Be changed to Ar.In the present invention, the variation of this process is finished by the computer control step-less adjustment.
17, oxidation is taken off C after require, and adds small amount of Fe-Si and makes slag have flowability slightly can to stay the slag tapping.Molten steel covers slag in bag, stir the last adjustment (preferably feeding the Ca-Si line) of deoxidation, sulphur; Melting and reducing early stage of staying that the slag in the stove then smelts at next stove, metal was gone in reduction in the lump.
Implement the present invention and produce the OCr13 stainless steel, the total losses of chromium always takes off S efficient (containing the melting and reducing phase) and reaches 95% less than 0.5%; 120 minutes tap to tap time, the melting and reducing time with take off C refining time half and half.
Supplementary material composition, size see Table 1, table 2.
Input-output see Table 3, and consumption of raw and auxiliary materials sees Table 4, and gained stainless steel composition sees Table 5.The chemical ingredients of chrome ore, iron ore and nickel oxide and size
Table 1
Chemical ingredients (%) | |
TCr Cr2O3 Fe2O3 FeO SiO2 Al2O3 MgO T.Fe | |
Chromite ore fine | 34.58 50.54 14.42 0.30 12.50 16.53 |
Cold group | 33.45 10.26 0.63 1.83 14.51 18.26 |
Iron ore | 62 |
NiO | |
The coke ashes | 0.97 7.63 6.50 0.18 |
Continuous table 1
Chemical ingredients (%) | Size (mm) | |
MnO P S Ni Na2O C CaO | ||
Chromite ore fine | 0.60 0.07 / / / / | 30 orders |
Cold group | 0.60 0.05 0.12 / 2.62 15.43 1.64 | 20-60 |
Iron ore | 0.03 | 10-30 |
NiO | 0.63 72.82 | 2-5 |
The coke ashes | 0.016 1.05 |
The Chemical Composition of coke and lime and size table 2
Fixed carbon | Ash | Fugitive constituent | CaO | SiO2 | MgO | Size (mm) | |
Coke | 80-81 | 16-17 | 3-4 | 20-26 | |||
Lime | 85 | ≤10 | <5 | 20-26 |
Produce OCr13 stainless steel input-output table look-up table 3
Project | Drop into | Output | ||||||||||||||
The raw material name | Chrome ore | Burnt C | Oxygen NM 3 | N2 NM 3 | Ar NM 3 | Lime t | Fe- Mn kg | Fe- Si kg | Fe- Ti kg | Molten metal | Flue gas | Waste gas | Slag | |||
Ton | Cr% | C% | TC | |||||||||||||
Ⅰ* | 10.5 | 12.4 | 7600 | 3100 | / | 2.7 | / | / | / | 17.7 | 17.5 | 5.70 | 1600 | 2.3 | 12600 | 7.8t |
Ⅱ* | SR phase molten metal 7.7t returns steel 6.6t | / | 3520 | 1130 | 210 | 1.5 | 90 | 408 | 70 | 23.5 | 13.1 | 0.11 | 1664 | 0.7 | 5400 | 3.2t |
Annotate: I is the melting and reducing phase; II is the Decarburising and refining phase
Consume table look-up table 4 when smelting OCr13
Contain C agglomerate kg/t | Furnace lining kg/t | Lime kg/t | O2 NM 3/t | N2 Ar NM 3/t NM 3/t | Coke kg/t | Cr oxidational losses % |
446.8 | 11.5 | 178.7 | 473 | 180 8.94 | 527 | 0.34 |
OCr13 stainless steel composition (Wt, %) table 5
C | Mn | P | S | Si | Ni | Cr | Cu | |
Mother liquor | 6.15 | 0.15 | 0.06 | 0.129 | 0.02 | 0.40 | 17.51 | 0.013 |
Stainless steel | 0.11 | 0.59 | 0.017 | 0.021 | 0.41 | 0.43 | 13.1 | 0.02 |
Claims (5)
1, a kind of method of directly smelting stainless steel by chromium ore fusion reduction, it is characterized in that: in top and bottom combined blown converter with bottom blowing air port and top rifle, by carbon-bearing pellet in the adding stove and/or the chromium in the carbon source reducing chrome ore stone in the carbonaceous material, after obtaining high chromium hot melt, in same converter, saturated carbonaceous high chromium hot melt is carried out Decarburising and refining, finally make stainless steel;
Melting reduction period:
(1) be blown into nitrogen from the bottom blowing air port or/and rare gas element, the stirring molten metal molten bath, the metal that forms protuberance at metal bath surface gushes;
(2) keep top rifle muzzle and metal bath surface apart from substantially constant, inert gas (1a) the impact metal that the top rifle is blown in the stove gushes, and pushes intensive carbon containing molten drop in the metal side of swarming to furnace wall mineral aggregate enrichment region, and the two fully stirs, mixes;
(3) tiltedly blow a combustion oxygen flow (1b) from the top rifle to in-furnace slag lower floor, the heating of metal bath, and avoid the re-oxidation of metal;
(4) be bordering on to the in-furnace slag upper strata from the top rifle and flatly be blown into two combustion oxygen flows (1c), heating and the efficient slag that stirs;
(5) mineral aggregate that adds in stove is the carbon-bearing pellet that breeze and carbon dust are bonded into, and makes slag lower floor reduction zone have enough carbon sources to participate in slag and bathes reaction, quickens the thawing reduction of chrome ore;
(6) according to chemical reaction in top rifle air supply intensity, gas shock metal pool intensity and the stove, the tone level that adopts detector to collect changes, and regulates the top rifle and makes the slag foaming height maximum, and control adds ore deposit speed to maximum;
(7) use CO
2The successive analysis instrument is measured CO in the stove
2Concentration, special post-combustion rate is protected more than 0.4 in control rifle position;
(8) after melting and reducing finishes, carry out deslagging, enter the Decarburising and refining phase;
In the Decarburising and refining phase:
(9) adopt rifle high chromium hot melt in stove in above-mentioned same top to be blown into the decarburization oxygen of using inert gas dilution, carry out the decarburization blowing;
(10) be blown into nitrogen or/and the stirring of inert gas metal pool from the bottom blowing air port.
2, the method for directly smelting stainless steel by chromium ore fusion reduction according to claim 1 is characterized in that: the carbon-bearing pellet that adds in the stove is the low strength nodulizing of carbon content 10~25%.
3, the method for directly smelting stainless steel by chromium ore fusion reduction according to claim 1 is characterized in that: 2~4 bottom blowing air ports be evenly distributed in the top rifle be the center of circle, burner hearth radius _~_ the furnace bottom circumference located on.
4, the method for directly smelting stainless steel by chromium ore fusion reduction according to claim 1, it is characterized in that: described top rifle is that double flow duct blows the top rifle for three layers again, melting reduction period, its muzzle is imbedded in the slag or near the metal bath surface, is blown into nitrogen respectively from bottom to top or/and inert gas, a combustion oxygen flow, two combustion oxygen flows from nozzle separately to the in-furnace slag layer.
5, the method for directly smelting stainless steel by chromium ore fusion reduction according to claim 1, it is characterized in that: in the Decarburising and refining phase, along with the minimizing of carbon content in the molten metal, reduce the oxygen level in the decarburization gas gradually, increase the ratio of rare gas element gradually; This process adopts the computer continuous stepless to regulate.
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---|---|---|---|---|
JP3721154B2 (en) * | 2002-10-18 | 2005-11-30 | 新日本製鐵株式会社 | Method for refining molten metal containing chromium |
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CN106222523B (en) * | 2016-08-01 | 2019-01-11 | 北京科技大学 | Method for making steel and top-blown powder rifle that chrome ore carries out alloying are added in vacuum environment |
CN109239193B (en) * | 2018-10-26 | 2021-05-04 | 山东钢铁股份有限公司 | Method for detecting converter slag |
CN114956912B (en) * | 2020-11-27 | 2023-08-01 | 胡波 | Process for fine blowing granular fertilizer once |
CN113532111B (en) * | 2021-07-19 | 2022-02-11 | 黄石市泓义城市矿产资源产业研究院有限公司 | Adjustable oxygen supply system and method for oxygen-enriched smelting furnace |
Citations (1)
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CN1047344A (en) * | 1989-05-19 | 1990-11-28 | 日本钢管株式会社 | Utilize the manufacture method of the stainless molten steel of smelting reduction |
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1995
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Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
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CN1047344A (en) * | 1989-05-19 | 1990-11-28 | 日本钢管株式会社 | Utilize the manufacture method of the stainless molten steel of smelting reduction |
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