CN1013883B - Method for manufacturing molten metal containing ni and cr - Google Patents
Method for manufacturing molten metal containing ni and crInfo
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- CN1013883B CN1013883B CN 90100853 CN90100853A CN1013883B CN 1013883 B CN1013883 B CN 1013883B CN 90100853 CN90100853 CN 90100853 CN 90100853 A CN90100853 A CN 90100853A CN 1013883 B CN1013883 B CN 1013883B
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Abstract
A method for manufacturing molten metal containing Ni and Cr comprising a process of smelting and reducing Ni ore, and a process of smelting and reducing Cr ore. The process of smelting and reducing Ni ore comprises the steps of charging molten iron into a smelting reduction furnace 10 having a top-blow oxygen lance and tuyeres for blowing stirring gas, charging Ni ore, carbonaceous material and flux into the smelting reduction furnace, blowing decarbonization oxygen and post-combustion oxygen from the top-blow oxygen lance into the smelting reduction furnace, blowing stirring gas for stirring the molten metal and slag inside the smelting reduction furnace from the tuyeres,and controlling post-combustion ratio at 0.3 or more. The process of smelting and reducing said Cr ore comprises charging Cr ore, carbonaceous material and flux into the smelting reduction furnace holding the molten metal containing Ni, blowing decarbonization oxygen and post-combustion oxygen from the top-blow oxygen lance into the smelting reduction furnace, blowing stirring gas for stirring the molten metal and slag inside the smelting reduction furnace from the tuyeres, and controlling post-combustion ratio at 0.3 or more.
Description
The present invention relates to the carbon containing thing be fuel or reductive agent, in the smelting reduction stove directly melting and reduced nickel ore and chrome ore with the method for the molten metal of producing nickeliferous and chromium.
Producing stainless melt refining step, the former scrap metal that all uses, the raw material of iron alloy and electrolytic nickel and so on, in electric furnace or steel melting furnace with these raw materials melt.As stainless main component nickel and chromium is that state with ferronickel and ferrochrome is added in electric furnace or the steel melting furnace.Nickel ores and chrome ore need to be reduced into ferronickel and ferrochrome in advance in the stove of electric furnace and so on, want the electric energy of consume expensive for this reason.Therefore we can say that using ferronickel or ferrochrome is not reasonable method economically as the method for raw material.
In addition, following four kinds of methods use not expensive raw material to be the nickel source.In first method, be to reduce the fusion cost, direct use ferronickel melts in electric furnace, this method in periodical " iron and steel ", describe in detail (" Iron and Steel " 69(1983, P.59).Second method is open in Japanese documentation 104153/83, and it is smelting reduction nickel source in steel melting furnace.The third method is disclosed in the Japanese documentation 36613/85, in this method, the oxide compound of nickel is mixed material heating and the prereduction that forms mixture with the carbon containing thing, then the material after this prereduction is added in the reactor of steel melting furnace and so on, smelting reduction, the 4th kind of method is disclosed in the Japanese documentation 291911/86, and this method has been used the oxide compound of nickel.
In addition, also have several method to adopt chrome ore as the chromium source; Chrome ore is melting and reduction in steel melting furnace or other smelting furnaces.For example, by from the top oxygen blast, from bottom spout oxygen blast and nitrogen flushing from the side simultaneously method with melting and reducing chrome ore stone; Also have in addition from bottom spout oxygen blast spout nitrogen flushing from the side simultaneously and oxygen method with melting and reducing chrome ore stone.As a kind of method example in back, narrate in the Japanese documentation 279608/86.
Problem in the prior art is discussed below.In the method for the nickeliferous molten metal of existing production, do not adopt nickel ores directly is added to method melting and reduced nickel ore in the smelting furnace.Because of nickel ores only contains 2～3%(weight) nickel, and the weight of nickel ores 80% can be transformed into slag, so in nickel ores smelting reduction process, can produce a large amount of slags, when attempting to obtain the nickel of predetermined content, also can produce a large amount of slags.For example, when obtaining containing the molten metal of 8% nickel, produce the slag that gold can produce the 2-3 ton that contains per ton.The generation of a large amount of slags can make following problems fairly obvious.
(1) in the smelting reduction step oxygen be added to carbon containing thing reaction in the smelting furnace as reductive agent or thermal source and be very easy to produce and slop over; Be difficult to so stably operate.
(2) owing to slop over, equipment is in damaged condition.
(3) owing to slop over, reduced the useful output of nickel.
In view of the above problems, during institute's quoted passage is offered in front, directly be not added in the smelting reduction stove as the nickel ores in nickel source, but adopted pre-treatment to make nickeliferous per-cent be increased to the material of a certain numerical value.
On the other hand, the chromated oxide as the chromium source is difficult to fusing, the energy that the reduction chromated oxide need be considerable; Therefore in the smelting reduction method of prior art, the rate of reduction of chromated oxide is very low, need remove to handle chromated oxide for a long time, and this problem can be used following cause description.
(1) in the smelting reduction stove, the reduction of chrome ore is after it is melted in the slag, by with the carbon containing thing in carbon reaction carry out gradually.The burn-off rate of chrome ore affects its reduction rate consumingly.Therefore, for shortening the technology required time, technical attention concentrates on to be measured on the slag composition.But chrome ore is infusibility really very, is limited with the reduction rate that promotes method that chrome ore melts to go to improve chrome ore.
(2) a kind of method being arranged is can be conceivable, makes the CO gas afterfire in the smelting furnace, and improves the burn-off rate of chrome ore in slag with this combustion heat, improves the speed of response of chrome ore thus.In prior art, also adopted the method that is blown into the afterfire requisite oxygen from top, furnace wall.But, in prior art,, effectively the heat in the waste gas is not transferred to the technical measures in the molten metal though improved the afterfire rate and improved spent air temperture.As a result, hot transfer efficiency is very low, and high-temp waste gas has been discharged.Such problem occurred, high-temp waste gas has been accelerated the wearing and tearing of exhaust zone refractory materials, and people be it is generally acknowledged, the afterfire rate can not be carried De Taigao.
Means with melting and reduced nickel ore and chrome ore can access nickeliferous and molten metal chromium.This is nickeliferous and molten metal chromium carries out carbonization treatment, can obtain stainless steel.Wish to be accompanied by smelting reduction process in the stove, in same stove, carry out carbonization treatment for breaking.In the past, also do not study the processing method of behind nickel ores and chrome ore smelting reduction, in same stove, molten metal being carried out carbonization treatment again.This true available following reason is explained.
(1) chromium oxidational losses significantly appears when carrying out carbonization treatment in the reactor of said molten metal at steel melting furnace and so on.Therefore, though nickel ores and chrome ore can be in the reactor of steel melting furnace formula smelting reduction, for carbonization treatment, also have to adopt the little vacuum method of chromium oxidational losses (for example RH-OB method).
(2) in carbonization treatment, need to measure greatly the gas of stirring action.In the smelting reduction process of prior art, can't expect how being supplied as and finish the necessary a large amount of stirring gases of carbonization treatment.Therefore, even expect finishing smelting reduction and carbonization treatment, can imagine that also the two structurally has very big difference with same-type steel melting furnace formula reactor.
(3) will decarburization in same stove, a large amount of slags that smelting reduction nickel chromium triangle ore is produced need be drained from the stove that carries out smelting reduction.But, the now conventional electric furnace that uses all do not have the to drain structure of slag.
(4) in the smelting reduction and decarbonization method of prior art, used time of smelting reduction and decarburization is all very long.Therefore, when smelting reduction and decarburization are carried out in same stove, finish all processing and will take the very long time.As a result, because production efficiency is low and the well damage of smelting reduction oven refractory, industrially be difficult to carry out such operation.
The object of the present invention is to provide a kind of method of producing the molten metal of nickeliferous and chromium, according to said method can stable operation and can improve nickel chromium triangle ore refining reduction ratio.
Method for the molten metal that reaches above-mentioned purpose, the invention provides the nickeliferous and chromium of the production that comprises the steps;
The smelting reduction nickel ores is made nickeliferous molten metal;
Smelting reduction chrome ore after making nickeliferous molten metal;
The process of smelting reduction nickel ores comprises the steps:
To melt molten iron and be added to top oxygen blast spray gun, decarburization nozzle and afterfire nozzle will be arranged on this spray gun, and blow in the smelting reduction stove that stirs the gas air port;
With nickel ores, carbon containing thing and fusing assistant are added in this stove again;
From said top oxygen blast spray gun decarburization oxygen and afterfire oxygen are blown into the smelting reduction stove;
To be blown into the gas of molten metal in the smelting reduction stove and slag stirring action in the smelting reduction stove from said air port;
The afterfire ratio is controlled at H
2O+CO
2/ H
2+ H
2O+CO+CO
2Be 0.3 or be higher than 0.3.
The step of said smelting reduction chrome ore is as follows:
In said, have in the smelting reduction stove of the nickeliferous molten metal by the preparation of above-mentioned smelting reduction nickel ores and add chrome ore, carbon containing thing and fusing assistant;
From said top oxygen blast spray gun decarburization oxygen and afterfire oxygen are blown into the smelting reduction stove;
To send into the stove the gas of molten metal in the smelting reduction stove and slag stirring action from said air port;
The afterfire ratio is controlled at H
2O+CO
2/ H
2+ H
2O+CO+CO
2Value be more than 0.3 or 0.3.
With following detailed description, above-mentioned purpose of the present invention and other purpose and advantage of the present invention will be very clear and definite in conjunction with the accompanying drawings.
Fig. 1 is the longitudinal diagram of explanation smelting reduction stove of the present invention;
Fig. 2 shows the explanatory view that concerns between predetermined afterfire rate of the present invention and the actual measurement afterfire rate;
Fig. 3 shows to overflow among the present invention to spill the explanatory view of now frequent degree and afterfire rate relation;
Fig. 4 shows to overflow among the present invention to spill the explanatory view that concerns between the now frequent degree and the bottom blowing scale of construction;
Fig. 5 is the explanatory view that shows the relation between the carbon content that slops in heavy S of time unit's slag and the molten metal;
Fig. 6 (A) and (B) be the explanatory view that shows operating process in the smelting reduction nickel ores of the present invention;
Fig. 7 shows the job description figure that stirs gas in the smelting reduction chrome ore process of the present invention to molten metal bottom blowing and side-blown;
Fig. 8 is when showing smelting reduction chrome ore of the present invention, in the smelting reduction stove, consumes the explanatory view of the relation between the coke amount with respect to the composition and the molten metal per ton of sulphur and phosphorus in the change molten metal of afterfire;
Fig. 9 is the explanatory view that shows smelting reduction chrome ore required time of the present invention;
Figure 10 A and B are the explanatory views that shows correlated method for smelting reduction;
Figure 11 shows the speed of comparing the composition increase of chromium in the molten metal of the present invention with the pure chromium of interpolation;
Figure 12 is the explanatory view that shows chromium oxidational losses and bottom blown gas magnitude relation among the present invention;
Figure 13 shows among the present invention the explanatory view that concerns between the loss of carbon content and chromium oxidation in the molten metal;
After Figure 14 A and B show the smelting reduction nickel ores, the variation of various operating parameterss in the process of smelting reduction chromium source and decarburization.
By the effect of decarburization oxygen, the carbon in the motlten metal is transformed into CO gas and therefrom overflows, and after-combustion oxygen is oxidized to CO with CO2 The heat that decarburization and after-combustion produce is the main thermal source of smelting reduction stove. The stirring gas that is blown into motlten metal from the bottom has strong stirring action to molten mass and slag, has promoted thus CO to become CO2Oxidation reaction. Therefore, when blender gas being blown into the smelting reduction stove and reacting with accelerating oxidation, can keep high after-combustion rate in the stove. This can produce a very large impact burn-off rate and the reduction rate that improves nickel ores and chrome ore.
After-combustion rate herein is by H2O+CO
2/H
2+H
2O+CO+CO
2Value representative.
When the smelting reduction nickel ores, improve the unit consumption (motlten metal per ton) that the after-combustion rate can reduce the coke (carbon containing thing) that adds in the smelting reduction stove. Correspondingly, also reduced CO gas and the CO that causes that appearance is overflow and spattered2The amount of gas. As a result, reduced widely the frequent degree that appearance is overflow and spattered. In addition, when with after increasing the Bottom Blowing scale of construction and improving heat transfer efficiency, can produce with to improve the after-combustion rate consistent The minimizing effect of overflowing and to spatter.
Melting has also been reduced after the nickel ores, wishes from drain slag and except dephosphorization of molten mass. Dephosphorization, make again the motlten metal desulfurization after, chrome ore is added in the smelting reduction stove. This process extremely works for preventing the chromium oxidation and improving operating efficiency.
When the chromium oxide that smelting reduction is difficult to reduce, for the carbon that is used in the motlten metal makes the chromium oxide reduction of staying the slag blanket bottom, when wishing than the smelting reduction nickel ores, under high after-combustion rate condition, stir more consumingly slag and motlten metal. For this reason, except bottom blowing was stirred, other adds side-blown was effectively. When the smelting reduction nickel ores, no matter whether blow side, improve bottom blowing tolerance and can reduce excessive spattering.
When nickeliferous and chromium motlten metal carbonization treatment, in motlten metal, blow into oxygen separately from top lance. At this moment, touch the dividing potential drop of motlten metal position (being called for short later on fiery point) oxygen for reducing gun slot, be blown into motlten metal by the oxygen of inert gas dilution. Simultaneously, the casual gas that is blown into from bottom tuyeres is stirring molten metal consumingly. The strong mixing effect of bottom blowing and dilution top blowing oxygen can promote the motlten metal decarburization and can limit the oxidational losses of chromium.
In the prior art, the oxygen blown situation from the bottom is arranged. But in the present invention, do not use oxygen as bottom blown gas. When oxygen during as bottom blown gas, produce a large amount of CO gas in the motlten metal and stirred excessively motlten metal, cause motlten metal to splash and be scattered. The motlten metal that is scattered that splashes can react with after-combustion oxygen, and this has just hindered the after-combustion of CO gas, thereby has reduced the after-combustion rate. In addition, if be bottom blown gas with oxygen, also need refrigerating gas is added in the bottom blown gas, damage when the excessive temperature in order to prevent the air port. The use cold gas is known from experience the splash phenomena that increases production cost and increased again melt because of the strong mixing effect of too having strengthened motlten metal.
Below, referring to concrete accompanying drawing, narration the preferred embodiments of the invention.Fig. 1 is the longitudinal diagram that shows smelting reduction stove 10 in the preferred embodiment of the invention.Among the figure, several 21 refer to top oxygen blast spray gun, the 22nd, and the decarburization nozzle, the 23rd, the afterfire nozzle, the 24th, the bottom blowing air port, the 11st, slag layer, the 12nd, molten metal, the 26th, to smelting reduction stove filling nickel and chrome ore, the hopper of carbon containing thing and fusing assistant.
In the smelting reduction stove of said structure was arranged, smelting reduction nickel and chrome ore can access higher afterfire rate, below its working condition of narration.
By C-CO and CO-CO
2Oxygen and carbon containing thing reaction, for melting nickel and chrome ore provide heat energy.The oxygen carbon main and molten metal that blows out from the decarburization nozzle 22 that places top oxygen-blowing gun 21 reacts and generation CO.Produce CO from oxygen and CO reaction that afterfire nozzle 23 blows out
2The oxygen symbol Pco that blows out from the decarburization nozzle
2Representative.Owing to arranged two kinds of nozzles 22 and 23, improved the afterfire rate.
In the present invention,, therefore realized high afterfire rate, obtained high heat transfer effect simultaneously owing to mainly form the afterfire district at slag blanket.For this reason, wish afterfire oxygen is blown in the slag, the afterfire district is mainly formed in slag.So just can guarantee that the afterfire rate is 0.3 or higher, obtain more nickelic and reduction ratio chrome ore, and in the reduction process of nickel and chrome ore, reduce the consumption of the carbon containing thing of unit molten metal.
In the present invention, do not wish with oxygen as stirring gas.When oxygen when stirring gas, can produce a large amount of CO gas and stirring molten metal excessively in the molten metal, thus Pco
2Carbon reaction with in the molten metal has hindered the afterfire reaction.Fig. 2 shows and uses N
2Be the situation and the comparison of oxygen that stirs gas for stirring gas.A represents to use N among the figure
2For stirring gas, it is to stir gas that B represents with oxygen; Transverse axis is represented the afterfire rate (Pco that is scheduled to
2/ Dco
2O in the+ore
2), the longitudinal axis represents to survey afterfire rate (H
2O+CO
2/ H
2+ H
2O+CO+CO
2).OD is the abbreviation of afterfire rate.When oxygen was stirring gas, actual measurement afterfire rate was lower than what be scheduled to, so can think that BOTTOM OXYGEN has hindered afterfire.
Said predetermined afterfire rate is based on all PCO of hypothesis
2All at afterfire consumption and all oxygen (DCO
2With the oxygen in the ore) all be used for the carbon of oxidation fusion metal.Therefore, the approaching more predetermined afterfire rate of actual measurement afterfire rate, then PCO
2The afterfire rate unreasonablely think.CO, N
2Or the rare gas element of Ar and so on all can separately or mix as stirring gas.
The process of smelting reduction nickel ores is carried out in narration with the smelting reduction stove 10 that can obtain high afterfire rate below.Earlier molten metal is put in the stove 10, after in stove, adding the carbon containing thing and making temperature of melt metal be raised to about 1500 ℃, again nickel ores is added in the stove from top oxygen blast spray gun 21 supply oxygen.Be added in the stove beginning from molten metal and just blow stirring gas to stove from air port, the end 24 and crosswind mouth 25.So just can prevent that the air port is plugged, also have, if desired, can increase the amount of being blown into that stirs gas.But, when the smelting reduction nickel ores, not needing to be blown into stirring gas from crosswind mouth 25 energetically, the gas volume that is blown into from crosswind mouth 25 can be just for keeping crosswind mouth 25 not to be plugged.This is because the effect of side-blown microgas is also not obvious.
Metallic amount is generally 20% in the nickel ores, and outside the metal content, the ore nickel content is 2-3%, and other 80% of ore is a slag.90% meeting that about ore is heavy changes slagging; The slag ingredient in nickel ores, the slag ingredient in the fusing assistant also drops in the slag.Therefore, can produce 2～3 tons slag for obtaining the alloy that contains 8% nickel per ton.Owing in the slag CO and CO are arranged
2, its apparent density is between 0.5～1.0, so the slag volume is 10～20 times of molten metal volumes.Producing excessive CO and CO
2Situation under, can occur overflowing and spatter.Can hinder stable operation like this, even interrupt run, machinery equipment damaged.
Based on this point, the inventor has studied the factor of overflowing and spattering that produces.Fig. 3 has shown the relation between interior afterfire rate of smelting reduction stove and the excessive frequent degree of spattering of appearance.Experiment condition is as follows: the capacity of smelting reduction stove is 7 tons, and carbon content is 1-2%, and the oxygen that provides for decarburization and afterfire is 2,500 standard m per hour
3, the heavy S of unit slag is 1 ton.Standard m
3Volume when referring to 0 ℃ in 1 normal atmosphere, the heavy S of unit slag is meant the slag of molten metal per ton heavy, represents with symbol T/HMT later on.As shown in Figure 3, when the afterfire rate was 0.15, the frequent degree of spattering that occurs overflowing was 50%, and this is quite high.When with changing the spray gun height or increase afterfire nozzle air-blowing quantity relatively when successfully having improved the afterfire rate, the frequent degree that spatters that occurs overflowing has just reduced.When the afterfire rate is 0.3 or more for a long time, in fact no longer occurred overflowing spattering phenomenon.
Its reason is that after having improved the afterfire rate, heat energy has increased, and can reduce the increasing amount of carbon containing thing thus, has reduced the amount that produces CO gas, so no longer take place to overflow to spatter phenomenon.Relevant therewith, afterfire (CO+O-CO
2) heat that produces is decarburizing reaction C+O-CO approximately) produce 2.5 times of heat.Among Fig. 4, the transverse axis representative is to the bottom blown gas amount of molten metal per ton.After the bottom blown gas amount increased, the frequent reduction of overflowing and spattering appearred.Excessive chance of spattering occurs because of by increasing the bottom blown gas amount said heat being passed in the molten metal effectively, having reduced, illustrated that raising afterfire rate more produces effect.The amount of wishing bottom blown gas fixes on 0.4Nm to molten metal per ton
3/ minute.The test conditions of situation shown in Figure 4 is identical with Fig. 3's.
Fig. 3 and experimental result shown in Figure 4 all are to obtain under unit slag weight is the condition of 1 ton/HMT.Can expect the situation that the heavy S of unit slag increases in experiment.Result of study to this is shown in Fig. 5, comprising occur to overflow spatter with molten metal in the relation of carbon content.Fig. 5 is carbon content and a unit slag heavy (T/HMT) and the excessive curve of relation that spatters in the molten metal.The afterfire rate is 0.3 or higher in the experiment.Among Fig. 5, the expression of symbol O place does not have excessive spattering, and steady running, the expression of symbol X place have to overflow spatters unsteady running.Broken string marks the border that expression does not have the excessive steady running district of spattering.The boundary curve of Fig. 5 can be represented with following relational expression:
S（T/HMT）＝3（C）%
Therefore, not having the available following relational expression in steady running district of spattering of overflowing represents:
S（T/HMT）＝3（C）%
Behind the above-mentioned smelting reduction of finishing nickel ores, the slag of from the smelting reduction stove, draining.Make the molten metal dephosphorization again, desulfurization.For making 5.9 tons of molten metal dephosphorizations, with 507 kilograms of lime, 70 kilograms of fluorites, 70 kilograms of iron filings (Scale) and 206 kilograms of cokes are dosed in the smelting reduction stove, and from top oxygen blast spray gun oxygen are blown into molten metal.It is heavy to account for 0.45%(in the molten metal) phosphorus reduce to that to account for 0.005%(heavy).
Then, from smelting reduction fire grate slag, and then desulfurization.For making 5.9 tons of molten metal desulfurization, with 15.2 kilograms of lime, 10 kilograms of fluorites, 10 kilograms of silicas and 526 kilograms of coke are dosed in the smelting reduction stove, and from the oxygen blast of top oxygen blast spray gun.Can make that to account for 0.6%(in the molten metal heavy) sulphur reduce to and account for 0.04%.
Fig. 6 (A) and (B) show specific examples by above-mentioned nickel ores method for smelting reduction.In this example, the afterfire rate is 0.3 or higher, and the carbon content in the molten metal remains on 1～2%(and weighs).The change of sequence number 1 expression operation steps among Fig. 6; The total oxygen-supplying amount of temperature 3 expressions of 2 expression molten masses, the degree of oxidation that 4 expression smelting reduction fire grates are given vent to anger, it is corresponding with the afterfire rate: the amount of nickel ores is dosed in 5 expressions; The amount of coke is dosed in 6 expressions along with the time.In operation steps sequence number 1, beginning is added to (hot metal charging step I) in the smelting reduction stove with 3.1 tons of molten state iron.Then, the deslagging of the melting and reducing of step 1-3 and step II-IV repeats.Carry out the dephosphorization of step 4 and the desulfurization of step 5 again.Dosing coke is raised to temperature of melt metal to be higher than 1500 ℃.The flat part of curve of expression oxygen-supplying amount 3, expression add the flat part of curve of nickel ores amount 5 and the respective value that flat part that expression adds the curve of coke amount 6 is represented respectively is 2900Nm
3/ hour, 120Kg/ divides and the 59Kg/ branch.
Each deslagging all makes the quantity of slag 7 reduce naturally.Shown in Fig. 6 B, the peak value of the quantity of slag is at 4.8～6.2 tons.In the smelting reduction stove, the fusion of beginning gold amount 7 is 3.1 tons and is increased to 5.9 tons at last, and this is also to be added in the molten metal of beginning because of nickel and iron that the smelting reduction nickel ores obtains.The content 8 of nickel can be high heavy to 4.5%(during deslagging in the first time in molten metal), and after dosing nickel ores three times in stove, the nickel content in the molten metal can be heavy up to 8.15%().
Finish the smelting reduction of nickel ores, after dephosphorization and the sweetening process, will carry out the smelting reduction process of chrome ore as described above.With chrome ore, carbon containing thing and fusing assistant are added in the molten metal of stove 10, just narrate the processing method that chrome ore is the chromium source herein, are not that to be only limited to chrome ore be the chromium source in the present invention.The same with the smelting reduction nickel ores, send oxygen to the smelting reduction stove from top blowing oxygen spray gun and afterfire nozzle, and also will be blown into stirring gas to a last step from air port, the end 24 in the first step of smelting reduction chrome ore.In this course, external except that being blown into microgas from air port, the end 24, also to will stir gas and blow to the smelting reduction stove from crosswind mouth 25.
Similar with the situation of aforementioned bottom blown gas, do not wish to stir gas as the side-blown in air port 25 with oxygen.If oxygen is side-blown gas,, thereby hindered the reduction of chrome ore because of the carbon in stirring and the slag blended molten metal can react with oxygen.In addition, similar to the situation in aforementioned bottom blowing air port, the problem of stove flame retardant coating also can appear damaging.
Fig. 7 is the process explanation figure that handles chrome ore with smelting reduction stove shown in Figure 1.Because of the chromic oxide in the ore is difficult to fusion, can not expect that the smelting reduction speed that restores after the chrome ore fusing can improve a lot.For actively promoting chrome ore to be melted the carbon reduction in the metal, blow stirring gas to the bottom of slag blanket 11 (at the chrome ore that suspending in addition) from crosswind mouth 25.Chrome ore mixes with molten metal like this.Simultaneously, be blown under the acting in conjunction of stirring gas in air port, the end 24 and crosswind mouth 25, molten metal mixes with slag.Can improve reduction rate effectively like this.In this process, because the effect of the stirring gas that bottom blowing air port 24 is blown into, molten metal forms dilation, shown in Fig. 7 (A).Meanwhile, stirring gas makes the gas that has at least a part to be blown into from crosswind mouth 25 can impact above-mentioned dilation (A.Because molten metal is scattering in the slag in the effect of side-blown gas, dilation (A).The apparent density of slag is generally 0.5～1.0.Therefore, chrome ore is suspended in the slag in most of slag, and concentrates on the bottom of slag blanket.When the dilation that makes molten metal because of cross air blow is scattered, the melt that is scattered just mix with the chrome ore of slag blanket 11 bottoms and melt in carbon can chromic oxide be reduced with fast speed very.
Equally, chrome ore also be the afterfire rate be 0.3 or higher condition under reduce.In addition, because the acting in conjunction of bottom blowing or side-blown has also improved heat passage effect greatly, thereby has reduced the coke consumption of molten metal per ton.Because of the most of phosphorus in the molten metal is brought into by coke (carbon containing thing), so under the less situation of the amount of dosing coke, the phosphorus composition amount also can reduce in the molten metal.From this point, the afterfire rate should fix on 0.3 or higher.Fig. 8 illustrates in the smelting reduction stove, the relation in the change of afterfire rate and the molten metal between phosphorus, sulphur composition and the coke unit consumption.Control afterfire rate is 0.3 or higher, can reduce phosphorus in the molten metal, sulphur composition and coke unit consumption.
Fig. 9 represents the comparison of the treatment time and the used time of comparison example shown in Figure 10 of smelting reduction chrome ore of the present invention.The said herein treatment time is meant from beginning and finishes to reduction reaction.In Figure 10 (A), shown from top lance to be blown into oxygen and fine breeze and to be blown into the control methods 1 of stirring gas from air port, the end.In Figure 10 (B), shown from top lance oxygen is blown on the slag, be blown into oxygen or nitrogen from the side-blown air port, be blown into the control methods 2 of nitrogen from the bottom blowing air port.Concrete operational condition is as follows:
Top blowing oxygen 1700Nm
3/ Hr(refers to when finishing reduction reaction)
Bottom blowing nitrogen 350Nm
3/ Hr(refers to when finishing reduction reaction)
10 tons of molten pigs
4600 kilograms of chrome ores (injecting) from a spray gun
6700 kilograms of carbon containing things (coal dust) (injecting) from a spray gun
Top blowing oxygen 1000Nm
3/ Hr(is when finishing reduction reaction)
Bottom blowing nitrogen 120Nm
3/ Hr(is when finishing reduction reaction)
Side-blown nitrogen 350Nm
3/ Hr(finish or during reduction reaction)
5 tons of molten pigs
5000 kilograms of chrome ores (dropping in the smelting reduction stove)
3000 kilograms of carbon containing things (coke) (dropping in the smelting reduction stove)
According to Fig. 9, in the control methods 2, the content of chromium has only 6-7%(to weigh) in control methods 1, it is 18% that the content of chromium reaches target, but need 120 minutes for handling chrome ore.In the method for smelting reduction chrome ore of the present invention, it is heavy that chromium content reaches 18%() only need 60 minutes treatment time, this lacks than control methods 1 uses half the time.This explanation, method of the present invention has extraordinary ability to handling chrome ore.In example of the present invention, after deliberation, the speed with respect to occurring chromium component in the speed molten metal of dosing chromium the results are shown in Figure 11.The said herein speed of dosing chromium is meant the speed of dosing chrome ore, with the numerical evaluation of the amount that is converted into pure chromium.In the method for smelting reduction chrome ore of the present invention, can obtain the speed that occurs in the molten metal of very fast chromium, and the speed that chromium occurs in control methods 1 and 2 is slower.Symbol zero among Figure 11 and △ have represented the obtained data of smelting reduction chrome ore of the present invention.Zero expression uses granularity to be raw material gained data as the chrome ore of 10mm, and △ represents to use granularity to be 1mm or the thinner chrome ore data as raw material.
Reduced after the chrome ore by above-mentioned, the slag of draining carries out carbonization treatment to nickeliferous and molten metal chromium again in same stove.Carbonization treatment is to rely on to send to oxygen in the stove and to blow into from the air port that stove is installed simultaneously from top oxygen blast spray gun to stir gas and carry out.At this moment, do not wish to use pure oxygen, should be blown into oxygen with inert gas dilution.Carbonization treatment is to be undertaken by following condition under environmental stress:
1. oxygen only is blown into from top lance 21, is not blown into from air port, the end;
2. what be blown into from top lance 21 is not pure oxygen, but with the oxygen of inert gas dilution;
3. be blown into rare gas element from air port, the end 24, intensely stirring molten metal.
Narrate below above-mentioned condition 1 and 3 the reason.In known AOD method, adopt from the oxygen blown method in furnace bottom air port.According to the inventor's research, can think that BOTTOM OXYGEN is to cause the reason that increases the chromium oxidational losses.In other words, because of BOTTOM OXYGEN has increased the static pressure of molten steel alloy, also improve the dividing potential drop of CO, so hindered decarburization.Therefore, do not adopt BOTTOM OXYGEN in the present invention, and blow oxygen from top lance 21.
Can think that only the means with top blowing oxygen can not prevent the chromium oxidational losses satisfactorily.Its reason is that decarburizing reaction occurs in mostly consumingly owing to send the fire point position that oxygen produces to from top-blown spray gun.Only blow into oxygen, can rise very highly in the dividing potential drop of this position CO; The result has hindered decarburizing reaction, and oxygen is with the chromium oxidation.Therefore, in the present invention, blow from the top blowing oxygen spray gun and to use N
2, the oxygen of the inert gas dilution of Ar and so on has reduced the CO dividing potential drop at fiery some position thus, has promoted decarburizing reaction.In order to shorten the time of carbonization treatment, wish to blow a large amount of gases from top lance.
In the present invention, for the gas that impels molten metal and top lance to send into mixes, also to blow rare gas element from air port, the end, stirring molten metal.Blow stirring of inert gas and the acting in conjunction that blows from top-blown spray gun with inert gas dilution oxygen from air port, the end, realized efficiently carbon rejection process and the Cr oxidational losses is controlled.
Be stirring molten metal consumingly, need a large amount of rare gas elementes is blown in the smelting reduction stove.For limiting the chromium oxidational losses particularly is 1% or still less, need blow 0.5Nm to molten metal per ton
3/ minute or more rare gas element.And limit the chromium oxidational losses is 0.5% or still less, just need blow 1Nm to molten metal per ton
3/ minute or more rare gas element.But, as blow into excessive gas, can cause being scattered of molten alloy.Therefore, in the present invention, molten metal bottom blown gas amount per ton is generally 0.5～5Nm
3/ minute, be preferably in 1-3Nm
3/ minute.
Figure 12 is illustrated in the relation between the chromium oxide loss in the bottom blown gas amount and carbon rejection process in the invention.By blowing a large amount of gases from the bottom blowing air port, effectively utilized oxygen, controlled the oxidational losses of chromium ideally.
For relatively, the loss amount of chromium oxidation in the decarbonization method of prior art and the relation of bottom blown gas amount are shown also among the figure.In the method for prior art, for example in the AOD method, the loss amount of chromium oxidation is sizable to the ratio of bottom blown gas amount.
In order more reasonably to reduce the loss of chromium oxidation, in the carbonization treatment process, effectively reduce the carbon content in the molten metal, thereby reduced the amount that blows oxygen supply.But in the oxygen supply of top oxygen blast spray gun, the reduction of spray feed pressure has certain limit, and reducing oxygen-supplying amount with nozzle has certain limit.Therefore, the amount that blows oxygen supply can only be reduced to half of maximum air demand.According to such situation, preferable methods is in decarburization oxygen blast process, improves constantly the per-cent of the rare gas element that is used for diluting oxygen in the top-blown gas, so just can blow under the pressure in reduction within reason, reduces oxygen-supplying amount with the decarburization progress effectively.
Increase rare gas element and can progressively carry out, can carry out continuously in other words with the minimizing oxygen-supplying amount.Narrate the concrete grammar of blow gas below.Send into the oxygen of using inert gas dilution from top-blown spray gun.To molten metal per ton, the gas volume of sending into from top-blown spray gun remains on 3Nm
3/ minute, wherein the amount of oxygen constantly changes according to the carbon content in the molten metal.
Carbon accounts for 3% or more 3Nm
3/ minute, molten metal per ton
Carbon accounts for 3～2% 2-3Nm
3/ minute, molten metal per ton
Carbon accounts for 2～0.5% 1-2Nm
3/ minute, molten metal per ton
Carbon is lower than 0.5% 1Nm
3/ minute, molten metal per ton
Infer according to the accumulation volume that blows into oxygen, perhaps measure the solidification value of molten metal sample, all can recognize the carbon content in the molten metal in the carbon rejection process.
Relate in the specific examples of chromium oxidational losses in the carbon rejection process one, its operational condition is similar to the condition in the operation steps shown in Figure 14.In this example, process carbonization treatment 40 minutes, the carbon content in the molten metal drops to 0.038% by 6.7%.Although molten metal decarburization is to low carbon content, the loss of chromium oxidation only has an appointment 0.5%, and this is quite low loss.Under these conditions, make the molten metal decarburization, the relation between research decarburizing reaction degree and the chromium oxidational losses with the degree that changes decarburizing reaction.Figure 13 has represented and AOD and the correlated result of LD-OB method.In example of the present invention, can think, even, also the loss of chromium oxidation can be restricted to enough low in the very low scope of carbon content.
The Figure 14 (A) and (B) specific examples of explanation smelting reduction chrome ore and carbonization treatment operational condition.Technological process shown in the figure is right after after the dephosphorization of smelting reduction nickel ores shown in Figure 6 and desulfurization operations step.In Figure 14 (A), the change of 1 expression operation steps, the carbon in the 2 expression molten metals and the content of chromium, 3 represent temperature of melt metal as time passes.Among Figure 14 (B), the change of 1 expression operation steps, the oxygen that 4 expressions blow out from spray gun and the amount of rare gas element, the 5th, the spray gun height, the 6th, the bottom blown gas amount, the 7th, the side-blown gas amount, the 8th, increase the chrome ore amount, the 9th, dose the coke amount.Figure 14 (A) and (B) in, sequence number 1-9 is corresponding.
In operation steps, produce slag in step 1, raise after the temperature deslagging I in the step 1 and carry out smelting reduction in step 2, reduce at last and finish in step 3, except that step 1-3, send into the amount of oxygen of 4 expressions from spray gun, the amount of the used oxygen of afterfire represents that with oblique line the amount of the used oxygen of decarburization is represented with blank parts.Then, carrying out desulfurization in step 4 after the deslagging II handles.In the carbonization treatment process, the amount that blows oxygen and nitrogen from spray gun is partly represented with blank parts and oblique line respectively.
Narrate below whole structure of the present invention. Blow into the smelting reduction stove because be used for the oxygen of carbonization treatment and after-combustion, smelting iron water is housed, nickel ores in the reduction furnace, coke (carbon containing thing) etc., and send stirring gas from the reduction furnace bottom blowing, therefore, the after-combustion rate can be mentioned 0.3 or higher and can not produce to overflow and spatter phenomenon. Therefore, can carry out steady running and guarantee that the availability of nickel is 90% or higher. Afterwards, blow stirring gas by the air port that is contained on the smelting reduction stove in stove, stirring molten metal carries out smelting reduction to the chromium material. So greatly improved the reduction rate of chromium source material, and made the chromium source material can in very short time, finish smelting reduction. In addition, because sending into oxygen in the stove from top lance and will stirring simultaneously the carbonization treatment process that gas is blown into motlten metal, so can reduce the oxidational losses of chromium. Also have, because above-mentionedly all carry out in same smelting reduction stove from smelting reduction to the carbonization treatment step, so use simple equipment, the short processing time can be raw material production stainless steel with nickel ores and chrome ore directly just, and the productive rate height, and production cost is low.
Claims (13)
1, comprise the smelting reduction nickel ores obtaining nickeliferous molten metal (12), and after obtaining said nickeliferous molten metal the smelting reduction chrome ore, the method with the molten metal of producing nickeliferous and chromium is characterized in that:
The process of smelting reduction nickel ores comprises the steps:
Molten hot metal is added in the smelting reduction stove 10 that top oxygen blast spray gun 21 and the air port that blows stirring gas are housed, decarburization nozzle 22 and afterfire nozzle 23 are arranged on said spray gun 21;
With nickel ores, carbon containing thing and fusing assistant are added in the said smelting reduction stove;
From said top oxygen blast spray gun, decarburization oxygen and afterfire oxygen are blown in the smelting reduction stove;
From said air port, blow the interior molten metal of stir-melting reduction furnace and the gas of slag;
With afterfire rate H
2O+CO
2/ H
2+ H
2O+CO+CO
2Be controlled at 0.3 or be higher than 0.3;
The process of smelting reduction chrome ore comprises the steps:
With chrome ore, carbon containing thing and fusing assistant are added to and contain in the smelting reduction stove of the resulting nickeliferous molten metal of process of smelting reduction nickel ores;
From said top lance, decarburization oxygen and afterfire oxygen are blown in the said smelting reduction stove;
From said air port, blow the interior molten metal of stir-melting reduction furnace and the gas of slag;
With afterfire rate H
2O+CO
2/ H
2+ H
2O+CO+CO
2
Be controlled at 0.3 or be higher than 0.3.
2, the described method of claim 1 is characterized in that, in the process of said smelting reduction nickel ores, also comprises carbon content (C%) and the per ton molten metal slag amount S(t/HMT of control in the molten metal) between relation, make it satisfy following formula:
S（t/HMT）≤3（C）%
3, the described method of claim 1 is characterized in that, in the process of smelting reduction nickel ores, said stirring gas is blown into from the air port 24 that is located at the smelting reduction furnace bottom.
4, the described method of claim 3 is characterized in that, the amount of blowing of said stirring gas is 0.4Nm to molten metal per ton
3/ minute or more.
5, the described method of claim 1 is characterized in that, in the process of smelting reduction nickel ores, controls the position of said top oxygen blast spray gun, makes its tail end in slag blanket 11.
6, the described method of claim 1 is characterized in that, in the process of smelting reduction chrome ore, controls the position of said top oxygen blast spray gun, makes its tail end in slag blanket 11.
7, the described method of claim 1 is characterized in that, in the process of smelting reduction chrome ore, the stirring gas that part is blowed impacts by air port, the end 24 and blown the expansible molten metal part that stirring gas causes.
8, the described method of claim 7 is characterized in that, the said microgas scale of construction that blows from air port, the end is 0.5～5Nm to molten metal per ton
3/ minute.
9, the described method of claim 8 is characterized in that, the said gas volume that blows from air port, the end is 1～3Nm
3/ minute.
10, the described method of claim 1 is characterized in that, in the process of smelting reduction nickel ores, used stirring gas is CO, N at least
2A kind of with among the Ar.
11, the described method of claim 1 is characterized in that, in the process of smelting reduction chrome ore, used stirring gas is CO, N at least
2A kind of with among the Ar.
12, the described method of claim 1 is characterized in that, it also comprises dephosphorization and sweetening process,
Said dephosphorizing process comprises:
After the smelting reduction nickel minerals obtains nickeliferous molten metal, the slag of draining;
Again with lime, fluorite, iron filings (Scale) and carbon containing thing are added in the smelting reduction stove;
From the oxygen blast to stove of top oxygen blast spray gun;
Said sweetening process comprises:
Arrange slag again and lime, fluorite, silica and carbon containing thing are added in the smelting reduction stove;
From the oxygen blast to stove of top oxygen blast spray gun.
13, the described method of claim 1 is characterized in that, also comprises nickeliferous and the carbonization treatment process chromium molten metal, and it comprises:
Blow the oxygen of using inert gas dilution from top oxygen blast spray gun;
Blow the molten metal in the stir-melting reduction furnace and the stirring gas of slag from the bottom blowing air port.
Applications Claiming Priority (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP042277/89 | 1989-02-21 | ||
| JP042278/89 | 1989-02-21 | ||
| JP4227789A JPH07100810B2 (en) | 1989-02-21 | 1989-02-21 | Method for producing molten alloy containing Ni and Cr |
| JP098152/89 | 1989-04-18 | ||
| JP1108897A JPH02285017A (en) | 1989-04-27 | 1989-04-27 | Production of molten stainless steel |
| JP108897/89 | 1989-04-27 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1045132A CN1045132A (en) | 1990-09-05 |
| CN1013883B true CN1013883B (en) | 1991-09-11 |
Family
ID=26381935
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 90100853 Expired CN1013883B (en) | 1989-02-21 | 1990-02-21 | Method for manufacturing molten metal containing ni and cr |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1013883B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5575829A (en) * | 1995-06-06 | 1996-11-19 | Armco Inc. | Direct use of sulfur-bearing nickel concentrate in making Ni alloyed stainless steel |
-
1990
- 1990-02-21 CN CN 90100853 patent/CN1013883B/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| CN1045132A (en) | 1990-09-05 |
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