300t answer blows converter half steel smelt turns slagging research and application without fluorine

Time:2023-06-20 13:49:50
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source:PURELIFE CNC Machining

Steelmaking process uses fluorite to regard slagging as the agent, the fluorine in the converter broken bits that the process produces changes calcium to be opposite of line of lining, bag erode very serious, and a large number of fluorine that fluorite produces are ionic, opposite state environment comes into being pollution. Long-term since, quality of use ore, fluorite is not stable, cause the difficulty that change broken bits, add a capacity big, increased to use up, also aggravate wait to line of lining, bag erode the pollution that reachs pair of environments. Accordingly, the research that has changing steel-making technology without fluorine and development have clear social beneficial result. The article is to be aimed at an iron of steel capital Tang Gang to combine finite liability company (below capital of abbreviation head steel the Tang Dynasty) use smelt of craft of converter double couplet when high quality steel is planted, develop the research that changes technology of half steel steel-making without fluorine and application, test result is clear, have bigger economic benefits. １ experiment condition and method head steel capital Tang You 5 300t converter, take a heart compound blowing technology, include 2 dephosphorization converter and 3 decarbonization converter among them, rise steadily as crop of half steel smelt, among them high quality steel is planted use half steel smelt basically entirely, when decarbonization converter smelt exceeds mild steel to plant, with advanced car board for exemple, requirement tapping ω (C) ＝ 0.

03 ％～ 0.

06 ％ , ω (P) ＜ 0.

01 ％ , ω (S) ＜ 0.

01 ％ , tapping temperature 1705 ℃ of 1675 ～ . Into furnace half steel composition and temperature see a table 1, produce structure and manufacturing cost optimization to come true, make full use of the dephosphorization ability of decarbonization furnace slag, already reached move of partial dephosphorization task decarbonization furnace, dephosphorization furnace place produces half steel now by target ω (P) ≤0.

030 ％ are adjusted for ω (P) ≤0.

035 ％ . Additional, head steel capital the Tang Dynasty content of phosphor of blast furnace molten iron is opposite stabler, in existing converter condition of double couplet craft falls, to use the steel-making that do not have fluorine stable production offerred precondition. 2 smelt craft is optimized 2.

The 1 course that become broken bits and research of operation leaving residue require a condition according to changing broken bits place, from position control of operation leaving residue, gun, broken bits a few respects are aimed at speed of complementary makings, decarbonization craft of slagging of Tang Mo fluorine has a steel capital industrial sex experiments. In initial stage of half steel smelt, join burn the slagging material such as dolomite lime, gently, when cold conditions lime and when contact leaving residue, as a result of slaggy with lime be infiltration, slaggy the stoma infiltration lime surface and crackle. Fe2 ＋ diffuses mediumly in broken bits speed is more than SiO44 - , the CaO that so Fe2 ＋ will enter the interior of lime piece to form low FeO content along air hole and crackle - the CaO of FeO solid solution and tall FeO - FeO fluid photograph, strange broken bits mixes at the beginning of this fluid get along with make content of the CaO in broken bits increases, lime begins fuse to be in broken bits. Meanwhile, the SiO44 that fails to enter lime interior - the silicon acid that makes high melting point with CaO action 2 calcium (C2S) overburden, make lime piece and slaggy separate, great decelerate lime fuse speed. Because tighten,the formation of C2S overburden is those who rely on lime surface is slaggy entered (C2S - L) 2 photographs area. Change slaggy composition to make 2 photographs area contractible, defer lime surface likely slaggy enter 2 photographs area and make C2S overburden attenuates. Through raising bath temperature is mixed add the group such as MgO, MnO, B2O3 appropriately to the middle of broken bits yuan the fuse that can quicken lime, in addition, because rich FeO is mixed between lime grain and C2S overburden,photograph of deficient SiO2 fluid infiltrates the existence of the layer, be helpful for Ca2 ＋ diffusing outwards, also can cause C2S overburden flake, cause the craze of lime piece possibly still at the same time, this is helpful for quickening the fuse of lime. The FeO in this shows broken bits has main effect to quickening lime fuse, use operation leaving residue to be helpful for raising the fusible rate of lime accordingly. SiO2 - CaO - FeO3 yuan phasor sees a picture 2, pursue among them 1 in small circle is denotive it is actual half steel smelt is terminal eventually broken bits composition is in 3 yuan of phasor distributing mediumly. Apparent, should reach this kind of part eventually the formation of broken bits the course may have a few kinds, but the influence difference that every kinds of course that become broken bits brings into broken bits rate and place is very big. By broken bits arrives first eventually broken bits can have 3 lines, it is a graph roughly 1 in ACB, ADB and AEB circuitry. Change of content of the FeO in the broken bits when pressing broken bits can call AEB tall ferric oxide to become broken bits way, ACB calls low ferric oxide to become broken bits way. Tall ferric oxide is good into fluidity of the slag in broken bits way, lime is fused fast, into broken bits fast, blowing metaphase slag is returned not easily dry, slag has capacity of good dephosphorization, to decoke very quickly; Low ferric oxide becomes melting point of the slag in broken bits way tall, lime is fused and slow, slag is ropy, blowing metaphase slag is returned easily dry, ability of the dephosphorization of slag, to decoke is weak. If converter smelt early days changes broken bits rate fast, criterion before smelt, metaphase dephosphorization ratio is relative taller, assured the dephosphorization result of terminal converter so. Head the effect changing broken bits that steel capital Tang Cai assures converter early days with operation leaving residue, stabilize and raise converter dephosphorization while can reduce broken bits the affiliation of complementary makings is measured. on one furnace second the part of broken bits of decarbonization converter steel-making of content of tall ferric oxide stays inside furnace (3 ～ 5 ｔ ) , such, the tall FeO in broken bits of second converter terminus meets on one furnace participate in below one furnace directly of second converter early days change broken bits, because earlier broken bits is medium (FeO) exist, make the fusible speed of lime is accelerated. Additional, belt leaving residue entered much physical heat, warm up quickly in blowing initial stage, the fuse that also is helpful for lime promotes broken bits. 2.

Means of 2 feed in raw material early days of half steel smelt, use operation leaving residue while can join slaggy agent help to change broken bits, besides tall gun outside generating FeO help to change broken bits more as far as possible, the Al2O3 composition in slaggy agent is joined to be able to drop melting point of the 2CaO•SiO2 in earlier broken bits in converter initial stage, form earlier broken bits quickly. 2.

The carbon in liquid of the metal inside 3 guns position control and converter of rate of carbolic oxygen response is main be oxidized with two kinds of means, it is the carbon in metallic liquid reacts with the oxygen of inbreathe directly, 2 be react with the FeOx in broken bits. By the graph 1 in the course that become broken bits can see, oxygen can be reduced with carbolic reaction directly generate FeO content, go against change broken bits, and direct oxidation reaction of carbon can emit much heat, make steel fluid warms up speed is accelerated, the oxidation career that makes carbon so is farther aggravate, carbon can use up the FeO in broken bits, make the FeO in broken bits decreases quickly, broken bits can be returned dry, and carbon reacts aggravate causes the splash of molten steel easily. Carbolic oxygen reaction is too sharp, steel fluid temperature warms up fast also, go against change broken bits, make the dephosphorization effect of broken bits drops. Graph 1 intermediary is mixed at ACB AEB is both the ADB between becomes broken bits way the shortest, requirement smelt process warms up quickly, bring about easily intense chemistry reacts and change broken bits to be not coordinated, bring about slag dephosphorization then rate is inferior, answer to avoid as far as possible. Use tall gun operation, aerobic efflux is abate to the concussion of steel fluid face, reduced the direct contact of oxygen and steel fluid face, at the same time the concussion face to broken bits can increase, such steel fluid warm up speed slows, carbolic oxygen reacts won't leap, at the same time the droplet in broken bits is oxidized, content of the FeO in broken bits is elevatory hurried evolution broken bits. 3 tests result 3.

1 slagging effect uses position control of operation leaving residue, gun, broken bits speed of complementary makings, decarbonization a few respect adjustment, among them half steel smelt leaves broken bits to measure 3 ～ 5 ｔ , tall gun position control, content of the FeO in assuring broken bits while the oxidation speed of the carbon in controlling steel, blowing early days joins carborundum and slaggy agent to adjust composition of early days broken bits, form early days broken bits as soon as possible. With smelt car board steel is planted for exemple, after using half steel to change slagging without fluorine, fluorite is used up by so 1.

78Kg/t arrives current disuse. 3.

2 dephosphorization effect with the car board steel smelt is exemple, converter is executed change contrast of circumstance of molten steel of terminus of operation around converter to see a picture without fluorine 2, after dephosphorization converter implementation changes craft to operate without fluorine, add converter broken bits to accept the restriction of lukewarm low requirement, fluid photograph rate can decrease relatively, bring about content of half steel phosphor to increase gradually thereby, bring about content of phosphor of decarbonization furnace terminus to also have the tendency that rise then (2a seeing a picture) . But change of rate of dephosphorization of decarbonization converter terminus is not big, can stable control in 72 ％ (2b seeing a picture) , it is better that the specification turns the case that change broken bits without fluorine. Half steel smelt changes phosphor of earlier converter terminus to allocate without fluorine than reducing, stabilize manufacturing hind to phosphorous allocation has fluorine to operate a level than returning and tend slowly stable, change operation engineering technology to maturing slowly without fluorine. 3.

The 3 economic benefits that change technology without fluorine head steel capital the Tang Dynasty decarbonization converter operation area before 2014 two months in all steel-making 4077 furnace,

800 thousand T, fluorite is used up by average 2013 0.

7Kg/t is reduced for 0, sheet cancels fluorite to use up, steel-making cost is reduced on average 1.

24 yuan / T, 2 months reduce cost 180.

790 thousand yuan, annual predicts to fall this synergism 10.85 million yuan. 4 conclusion 1) converter uses position control of operation leaving residue, tall gun, add rate of decarbonization of flux, control photograph of a few respects combines what can replace fluorite to turn broken bits result. 2) industrial application makes clear, change slagging craft to optimize a technology without fluorine practical, can stabilize control place to need steel to plant phosphorous content. CNC Milling