CN111471832A - Deep sulfur and phosphorus removing method for less-slag steel making - Google Patents
Deep sulfur and phosphorus removing method for less-slag steel making Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/064—Dephosphorising; Desulfurising
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- C21C7/068—Decarburising
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
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Abstract
The invention relates to a method for deeply removing sulfur and phosphorus in less-slag steel making, belongs to the technical field of steel making, and solves the problems of high steel slag yield and difficulty in utilization in the prior art. The method for deeply removing sulfur and phosphorus in the less-slag steel-making provided by the invention comprises the following steps: step 1, adding an alkaline flux into molten iron for desiliconization and decarburization to obtain low-alkalinity and low-iron steel slag and molten steel; step 2, desulfurizing molten steel by using a desulfurizing agent Zn to obtain desulfurized molten steel; step 3, deep decarburization is carried out on the molten steel; when the carbon content in molten steel is less than 0.5%, CO containing ZnO powder is used2Dephosphorizing the molten steel by using gas to obtain a zinc phosphate melt and dephosphorized molten steel; and 4, reducing the zinc phosphate melt by using solid carbon to obtain phosphorus and metal zinc, recycling the phosphorus, and returning the metal zinc serving as a desulfurizing agent to the step 2. The invention can greatly reduceThe production amount of the steel slag reduces the free CaO and iron content of the steel slag, improves the utilization rate of the steel slag and thoroughly solves the problem of stacking the steel slag.
Description
Technical Field
The invention relates to the technical field of dephosphorization and desulfurization of steel slag, in particular to a method for deeply removing sulfur and phosphorus in less-slag steel making.
Background
Converter slag needs high alkalinity to meet the requirements of dephosphorization and desulfurization, a large amount of alkaline flux is needed to be added for slagging in the steel making process, meanwhile, the dephosphorization process is carried out in an oxidizing atmosphere, and in order to ensure the dephosphorization efficiency, a certain content of ferric oxide in slag phase must be ensured, so that the slagging process not only needs to consume a large amount of alkaline flux, but also causes a large amount of loss of iron. In addition, when the dephosphorization and desulfurization processes of the converter are carried out under the same slag condition, the strong oxidizing atmosphere is not beneficial to sulfur removal, the sulfur removal limit is limited, further deep desulfurization needs to be carried out in the ladle furnace, and the treatment flow and the cost are increased.
The steel production capacity of China is huge, and about 120-150 kg of steel slag is generated every 1t of molten steel, so that the yield of the steel slag is huge. The steel slag is firstly cooled through hot braising treatment, then slag steel, slag steel powder and tailings are respectively obtained through dry magnetic separation, the metal iron content of the slag steel is high, the slag steel is returned to a converter for steelmaking, the slag steel powder is returned to a rotary furnace to be used as a coolant or used in a sintering process, the tailings have two treatment modes, firstly, the slag steel powder is used as a paving material, firstly, the slag steel powder and the steel slag micropowder are obtained through further grinding and magnetic separation, and the tailings are used as steel slag cement ingredients. Because the steel slag has high alkalinity, the tailings contain certain content of free CaO and MgO, and calcium silicate is in a metastable phase after quenching, so that the structure stability of the tailings is poor, and the tailings need to be stacked to be stabilized when being directly used as backfill or paving material, so that the time consumption is long; secondly, the iron content of the tailings is high, the strength is affected when the tailings are used as an additive of cement or concrete, the addition amount is generally controlled within 30%, and the use amount is limited; finally, the magnetic separation powder has low iron taste and high phosphorus content, and can cause phosphorus enrichment in molten iron when used as sintering ingredients, reduce the iron grade of sintered ores and improve the treatment cost of the molten iron. Therefore, the utilization difficulty of the steel slag is high, and the steel slag is mainly piled up at present, so that the resource waste is caused, and meanwhile, a severe environmental problem is caused.
At present, the recycling of the steel slag in the steel-making process becomes a new research direction, and the recycling of the steel slag is realized by carrying out reduction dephosphorization treatment on the steel slag, so that the flux consumption and the steel slag yield are reduced. But in the process of steel slag reduction dephosphorization, iron oxide is reduced into molten iron at the same time, most of phosphorus enters the molten iron and circulates in a steelmaking system, and the effective removal rate of the phosphorus is low; in addition, when the steel slag is recycled, the sulfur content is gradually increased, the effective CaO content is reduced, the dephosphorization and desulfurization effects in the steel-making process are influenced, and the significance of steel slag emission reduction is weakened.
The converter steelmaking process is divided into a slagging period (silicon and manganese oxidation period), a carbon oxidation period and a dephosphorization and desulfurization period, wherein the dephosphorization and desulfurization all need higher alkalinity, so that the steel slag flows away from CaO with high content, and meanwhile, the dephosphorization needs high oxidizability, so that the iron oxide content of the steel slag is high, and the steel slag flux consumption is large and difficult to utilize due to the reasons.
Disclosure of Invention
In view of the above analysis, the embodiment of the present invention aims to provide a method for deeply removing sulfur and phosphorus in steel making with less slag, so as to solve the technical problems of a large amount of steel slag generated during steel making with molten iron and a large amount of iron loss caused by adding a large amount of alkaline flux during steel slag treatment in the prior art.
The purpose of the invention is mainly realized by the following technical scheme:
the invention discloses a deep sulfur and phosphorus removal method for less-slag steel making, which comprises the following steps:
step 1, slagging, desiliconizing and decarbonizing stages;
adding an alkaline flux into molten iron, reducing FeO formed at the initial slagging stage by CO gas generated in a decarburization period, and separating molten slag from molten steel after desiliconization and decarburization are finished to obtain low-alkalinity and low-iron steel slag and molten steel;
step 2, reduction and desulfurization;
with N2Spraying a desulfurizing agent Zn from the bottom of the molten steel for carrier gas, reacting the Zn with sulfur in the molten steel to generate ZnS, and separating the ZnS to obtain desulfurized molten steel;
step 3, carrying out deep decarburization and deep dephosphorization on the desulfurized molten steel;
deep decarburization is carried out on the molten steel by using a decarburization oxidant before dephosphorization; when the carbon content in the molten steel is less than 0.5%, spraying CO containing ZnO powder from the bottom of the molten steel2Gas, the decarburization and dephosphorization reactions are carried out simultaneously, and the dephosphorization product is separated to obtain a zinc phosphate melt and dephosphorization molten steel, wherein C in the dephosphorization molten steel is less than 0.25 percent, and P in the dephosphorization molten steel is less than 0.002 percent;
step 4, reducing the zinc phosphate melt by using solid carbon to obtain metal zinc steam and phosphorus steam, and separating the metal zinc from the phosphorus steam after condensing by using the different boiling points of the metal zinc steam and the phosphorus steam; and (4) recycling the phosphorus, and returning the metal zinc as a desulfurizing agent to the step (2) for recycling.
Further, in the step 2, the mass ratio of Zn to S is 1.2-1.5, the density difference exists between ZnS and molten steel, ZnS floats on the surface of the molten steel, and the ZnS and the molten steel are separated through slag skimming;
s in the desulfurized molten steel is less than 0.003 percent.
Further, in step 2, ZnS is oxidized with pure oxygen to obtain SO3Gas and ZnO, SO3And (3) absorbing the gas by water, and then preparing sulfuric acid, wherein ZnO is used as a dephosphorizing agent and returns to the step 3 for recycling.
Further, in step 4, the generated CO gas is converted into CO after being used as fuel for combustion2Flue gas, CO2The flue gas is used as a decarburization oxidant and returned to the step 3 for recycling.
Further, in step 3, the decarbonizing oxidizing agent is CO2，CO2Blowing in CO from the bottom of the converter through an oxygen lance2The molar ratio of (0.5Si + C) is 1 to 1.1.
Further, in step 3, the decarburization oxidant is O2，O2Blowing in CO from the bottom of the converter through an oxygen lance2The molar ratio of (0.5Si + C) is 0.5 to 0.55.
Further, in the step 3, the mass ratio of ZnO/P is 4-4.5, and carrier gas CO of ZnO powder2The molar ratio of/P is 2.6-3.0.
Further, in the step 1, the alkaline flux is quicklime, the alkalinity of steel slag in the low-alkalinity and low-iron steel slag is 1.4-2.0, and the content of FeO is 5-10%; the Si content in the molten steel is less than 0.01 percent, and the C content is less than 0.25 percent.
Further, in the step 4, reduction is carried out in a steel ladle, and the reduction temperature is 1100-1500 ℃.
Further, the low-alkalinity and low-iron steel slag in the step 1 is used for preparing building material raw materials.
Compared with the prior art, the invention can realize at least one of the following beneficial effects:
(1) the invention only carries out the removal of silicon and carbon in the slagging smelting process, does not need to produce high-alkalinity and high-oxidability slag, and has the following beneficial effects: firstly, the invention can greatly reduce the consumption of the alkaline flux; secondly, the iron oxide content of the slag phase is greatly reduced after the oxidizability of the slag is reduced, and meanwhile, the melting temperature is reduced after the alkalinity of the slag is reduced, so that the inclusion of metallic iron in the slag phase is avoided, the loss of iron in the slag phase can be effectively reduced, and the existence of free-flowing CaO and metallic iron of the steel slag is eliminated, the utilization activity of the steel slag is improved, and the full utilization of the steel slag can be realized; the metallic zinc is used as a desulfurizer, and the zinc is N2The molten steel is sprayed into the carrier gas from the bottom, so that the effect of stirring a molten pool can be achieved, the desulfurization efficiency is improved, the metal zinc is not dissolved in the iron, and the pollution of a desulfurizing agent to the molten steel is avoided.
(2) The invention uses CO2The carrier gas is a decarburization oxidant and ZnO powder, so that the volatilization loss of iron caused by the violent reaction of oxygen and metallic iron can be avoided; the desulfurization product ZnS is oxidized by pure oxygen, SO that the SO in the flue gas can be increased while the flue gas amount can be reduced3The content of the ZnO is increased, so that the preparation efficiency of the sulfuric acid is improved, and the ZnO returns to the dephosphorization stage for cyclic utilization, so that waste residue discharge is avoided;
(3) after the dephosphorizing product zinc phosphate is directly reduced by using solid carbon, based on the difference of boiling points, phosphorus is recovered to prepare white phosphorus or red phosphorus, and metal zinc is returned to the desulfurization stage of the step 3 for utilization, so that no waste residue is generated for discharge; CO generated in the dephosphorization stage and the dephosphorization product reduction stage is used as high-calorific-value coal gas, and combustion flue gas returns to the dephosphorization stage for cyclic utilization, so that the flue gas emission is reduced.
(4) The method for deeply removing sulfur and phosphorus in the steel making with less slag provided by the invention can greatly reduce the generation amount of the steel slag, simultaneously reduce the content of free CaO and iron in the steel slag, improve the utilization rate of the steel slag and thoroughly solve the problem of stacking caused by the steel slag. Meanwhile, the content of free CaO and iron in the steel slag is reduced, the utilization rate of the steel slag is improved, and the problem of stacking caused by the steel slag can be thoroughly solved.
In the invention, the technical schemes can be combined with each other to realize more preferable combination schemes. Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and drawings.
Drawings
The drawings are only for purposes of illustrating particular embodiments and are not to be construed as limiting the invention, wherein like reference numerals are used to designate like parts throughout.
FIG. 1 is a process flow diagram of a method for deeply removing sulfur and phosphorus in less-slag steel making.
Detailed Description
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate preferred embodiments of the invention and together with the description, serve to explain the principles of the invention and not to limit the scope of the invention.
The invention discloses a method for deeply removing sulfur and phosphorus in less-slag steel making, which comprises the following steps of:
step 1, slagging, desiliconizing and decarbonizing stages;
adding quicklime into molten iron for steelmaking (S is less than 0.05 percent, P is less than 0.05 percent, Si is less than 0.2 percent, and C content is about 4 percent), wherein the adding amount of the quicklime is determined according to the Si content in the molten iron, because sulfur and phosphorus do not need to be removed in the step 1, the alkalinity and the oxidability of a slag phase are not required, the alkalinity of the steel slag can be controlled to be 1.4-2.0, the complete removal of silicon is ensured, the horizontal range is far lower than the alkalinity of the traditional steel slag by 3.0-5.0, a large amount of CO gas is generated in a decarburization period to reduce a large amount of FeO formed in a slagging period, the FeO content in the steel slag is controlled to be within 5-10 percent by measuring the [ O ] content of the steel slag, the steel slag is ensured to have certain fluidity, the separation of the steel slag and the molten steel is facilitated, the inclusion of metallic iron in the.
[Si]+2[O]＝(SiO2) (1)
[C]+[O]＝CO(g) (2)
CO(g)+(FeO)＝[Fe]+CO2(g) (3)
After desiliconization and decarburization are finished, slag and molten steel are separated to obtain low-alkalinity and low-iron steel slag with the alkalinity of 1.4-2.0 and the FeO content of 5-10%, the low-alkalinity and low-iron steel slag is used for preparing building material raw materials, and desulfurization and decarburization treatment are carried out on the molten steel (the Si content is lower than 0.01% and the C content is lower than 0.25%).
Step 2, reduction and desulfurization;
with N2Spraying a desulfurizing agent Zn from the bottom of molten steel for carrier gas, controlling the mass ratio of Zn to S to be 1.2-1.5 so as to ensure the removal limit of sulfur, simultaneously avoiding excessive consumption of Zn, reacting Zn with sulfur in the molten steel to generate a ZnS high-melting-point substance, floating the ZnS high-melting-point substance on the surface of the molten steel based on the density difference of the ZnS high-melting-point substance and the molten steel, and separating the ZnS high-melting-point substance from the molten steel through slag skimming treatment to obtain desulfurized molten steel (S is less than 0.003%); oxidizing the ZnS high-melting-point substance by using pure oxygen to obtain SO3Gas and dephosphorizing agent ZnO, SO3Absorbed by water and used for preparing sulfuric acid.
Zn+[S]＝ZnS (4)
ZnS+2O2(g)＝ZnO+SO3(g) (5)
Step 3, deep decarburization and dephosphorization are carried out on the desulfurized molten steel;
in order to prevent the Zn from being volatilized and lost due to the reduction of ZnO by residual carbon in molten steel to form metallic Zn, deep decarburization is carried out before dephosphorization is carried out, and CO is used2Or O2Blowing CO as decarbonizing oxidant from the bottom of converter through oxygen lance2V (0.5Si + C) molar ratio of 1 to 1.1, O2/(0.5Si + C) molThe ratio is 0.5 to 0.55.
When the carbon content in the molten steel is reduced to below 0.25%, spraying CO containing ZnO powder from the bottom of the molten steel2Gas, CO2As oxidizing gas, ZnO as carrier gas to ensure sufficient contact between ZnO powder and molten steel, ZnO/P mass ratio of 4-4.5, and carrier gas CO2The mol ratio of/P is 2.6-3.0, so that a good dephosphorization effect can be ensured; meanwhile, the decarbonization and dephosphorization reactions are carried out simultaneously, and the low-carbon and low-phosphorus molten steel (C is less than 0.25 percent and P is less than 0.002 percent) and the low-melting-point zinc phosphate melt are obtained by separating the dephosphorization products, and the low-melting-point zinc phosphate melt and the molten steel are easy to separate in a layered manner.
[C]+CO2(g)＝2CO(g) (6)
CO2(g)+[Fe]＝CO(g)+(FeO) (7)
(FeO)＝[Fe]+[O](8)
3ZnO+2[P]+5[O]＝Zn3(PO4)2(9)
Step 4, dephosphorizing product reduction stage;
and (3) reducing the zinc phosphate separated in the step (3) by using solid carbon at 1100-1500 ℃ in a steel ladle to obtain metal zinc steam and phosphorus steam, separating the metal zinc from the phosphorus steam after condensation based on different boiling points of the metal zinc steam and the phosphorus steam, recycling phosphorus, and returning the metal zinc as a desulfurizing agent to the step (2) for recycling.
Zn3(PO4)2+8C＝3Zn(g)+4P2(g)+8CO(g) (10)
CO gas generated in the step is used as fuel to be combusted and utilized and then is converted into CO2Flue gas, CO2The flue gas is used as a decarburization oxidant and returned to the step 3 for recycling.
Only silicon and carbon are removed in the slagging smelting process, the alkalinity and the oxidability of the steel slag are low in the desiliconization and decarburization processes, and the consumption of an alkaline flux and the iron loss are reduced; the metallic zinc is used as a desulfurizer, and the zinc is N2The molten steel is sprayed into the carrier gas from the bottom, the effect of stirring a molten pool can be achieved, the desulfurization efficiency is improved, the metal zinc is not dissolved in the iron, and the steel is prevented from being treated by a desulfurizing agentContamination of water.
For deep dephosphorization with CO2The carrier gas is a decarburization oxidant and ZnO powder, so that the volatilization loss of iron caused by the violent reaction of oxygen and metallic iron can be avoided; the desulfurization product ZnS is oxidized by pure oxygen, SO that the SO in the flue gas can be increased while the flue gas amount can be reduced3The content of the ZnO is increased, so that the preparation efficiency of the sulfuric acid is improved, and the ZnO returns to the dephosphorization stage for cyclic utilization, so that waste residue discharge is avoided; after the dephosphorizing product zinc phosphate is directly reduced by solid carbon, based on the difference of boiling points, the phosphorus is recovered to prepare white phosphorus or red phosphorus, and the metal zinc is returned to the desulfurization stage for utilization, so that waste residue discharge is avoided.
And (4) burning CO generated in the dephosphorization stage in the step (3) and the dephosphorization product reduction stage in the step (4) as high-calorific-value coal gas, and returning the generated combustion flue gas to the dephosphorization stage in the step (3) for cyclic utilization, so that the emission of flue gas is reduced.
Example 1
Pure iron, ferrosilicon and graphite powder pure chemical reagents are used as raw materials and are completely melted in a medium-frequency induction furnace to prepare molten iron with the silicon content of 0.15 percent and the carbon content of 3.5 percent for desiliconization and decarburization, the temperature is 1650 ℃, and the mass of the molten iron in each furnace is 20 kg.
After the molten iron is completely melted, flux quicklime (pure chemical reagent) is added as desiliconization agent, and O is blown to the bottom of the molten iron through a corundum tube2，O2The gas flow is 20L/min, blowing time reaches 35min, then oxygen blowing is stopped, standing is carried out for 10min, then a small amount of molten steel and slag are respectively extracted by a sampler, the molten steel and the slag are cooled and crushed into small steel particles and slag particles, and the silicon content of the steel particles and the FeO content of the slag particles are respectively determined by chemical analysis, the adding amount of the quicklime is determined according to the Ca/Si molar ratio, and the Ca/Si molar ratio is 1.0, 1.2, 1.4, 1.6, 1.8 and 2.0 respectively.
The changes of the molten steel and slag compositions at different amounts of quicklime added are shown in Table 1. It can be seen that the silicon content of the molten steel is gradually reduced along with the increase of the adding amount of the quicklime, and the requirement of the medium molten steel composition can be met when the FeO content in the slag is gradually increased and the Ca/Si molar ratio is controlled to be 1.4-2.0.
TABLE 1 molten steel and slag compositions
Example 2
Pure iron and FeS pure chemical reagents are used as raw materials and are completely melted in a medium-frequency induction furnace to prepare molten steel with the S content of 0.05% for a desulfurization experiment, the experiment temperature is 1650 ℃, and the mass of the molten steel in each furnace is 20 kg.
Zinc particles are added into the molten steel through the corundum tube, the adding amount of the zinc particles is 0.05-0.2% of the mass of the molten steel respectively, the adding amount of each time is 0.05%, the corundum tube is inserted into the bottom of the molten steel, the zinc is prevented from rapidly escaping from the molten steel after being vaporized, and the reaction time of the zinc and the molten steel is prolonged. Waiting for 10min after adding zinc particles each time, extracting a small amount of molten steel by a sampler after the components of the molten steel are completely uniform, crushing the molten steel into small steel particles after cooling, and measuring the sulfur content of the steel particles by adopting a carbon-sulfur analyzer.
The experimental result shows that when the adding mass of the zinc particles is respectively 0.05%, 0.1%, 0.15% and 0.2%, the sulfur content of the molten steel is reduced to 0.013%, 0.003%, 0.002% and 0.001%, the sulfur content of the molten steel is remarkably reduced when the adding amount of the zinc particles is increased, and when the adding amount of the zinc particles reaches 0.1%, the sulfur content of the molten steel can be controlled below 30ppm, so that the sulfur content requirement of the molten steel is met. The actual addition amount of zinc particles is related to the sulfur content of molten steel, and the Zn/S mass ratio can meet the requirement when being controlled to be 1.2-1.5.
Example 3
Pure iron and pure chemical reagent of iron phosphide are used as raw materials, and are completely melted in a medium frequency induction furnace to prepare molten steel with the P content of 0.15% for dephosphorization experiments, the experiment temperature is 1650 ℃, and the mass of the molten steel in each furnace is 20 kg.
ZnO powder reagent is added into molten steel through a corundum tube and stirred, so that ZnO is dispersed in the molten steel, the addition amount of ZnO is 0.5-0.8% of the mass of the molten steel, the first addition amount is 5%, and then 1% is added each time. After each addition of ZnO, the molten steel is poured to the bottom through a corundum tubeBlowing CO2Gas, CO2The gas flow is 2L/min, the spraying time is 30min after the ZnO is added for the first time, the spraying time is 6min after each ZnO is added, the mixture is kept stand for 10min after each spraying is finished, the formed FeO is ensured to fully react with the ZnO and the P to form zinc phosphate, a small amount of molten steel is extracted by a sampler, the molten steel is cooled and crushed into small steel particles, and the phosphorus content of the steel particles is determined by chemical analysis.
As a result, the amounts of ZnO powder added were 0.5%, 0.6%, 0.7%, and 0.8%, respectively, and the phosphorus contents in the molten steel were 0.04%, 0.0012%, 0.0007%, and 0.0005%, respectively. It can be seen that the phosphorus content of molten steel is reduced to 15ppm or less after the addition amount of ZnO reaches 6%. The actual addition amount of ZnO is related to the phosphorus content of molten steel, and the dephosphorization requirement can be met when the mass ratio of ZnO/P is controlled to be 4-4.5.
Example 4
Pure iron and pure chemical reagent of iron phosphide are used as raw materials, and are completely melted in a medium frequency induction furnace to prepare molten steel with the P content of 0.05 percent for dephosphorization experiments, the experiment temperature is 1650 ℃, and the mass of the molten steel in each furnace is 20 kg.
ZnO powder reagent is added into the molten steel through a corundum tube and stirred, so that ZnO is dispersed in the molten steel, and the addition amount of ZnO is 0.6 percent of the mass of the molten steel. After the ZnO is added, blowing CO to the bottom of the molten steel through a corundum tube2Gas, CO2The gas flow is 2L/min, the blowing time is 24-32 min, and CO is2Standing for 10min after blowing for 2min to ensure that the formed FeO fully reacts with ZnO and P to form zinc phosphate, then extracting a small amount of molten steel by a sampler, cooling and crushing the molten steel into small steel particles, and determining the phosphorus content of the steel particles by chemical analysis.
The results show that when CO is present2When the blowing time is 24min, 26min, 28min, 30min and 32min, the phosphorus content of the molten steel is 0.012%, 0.005%, 0.002%, 0.0014% and 0.0009%, respectively. It can be seen that CO2The phosphorus content of the molten steel is reduced to below 15ppm after the blowing time reaches 30min, and the phosphorus content of the molten steel is not obviously reduced after the blowing time exceeds 30 min. CO 22The actual blowing time of (A) is related to the phosphorus content of the molten steel, CO2The mol ratio of/P is controlled to be 2.6-3.0, and the dephosphorization requirement can be met。
Example 5
Pure iron, ferrosilicon, graphite powder, FeS and an iron phosphide pure chemical reagent are used as raw materials and are completely melted in a medium-frequency induction furnace to prepare molten iron with the silicon content of 0.15 percent, the carbon content of 3.5 percent, the S content of 0.05 percent and the P content of 0.05 percent, the experimental temperature is 1650 ℃, and the mass of the molten iron is 20 kg.
After the molten iron is completely melted, adding a quicklime pure chemical reagent as a desiliconization agent, wherein the Ca/Si molar ratios are 1.4 and 1.8 respectively, and simultaneously blowing O to the bottom of the molten iron through a corundum tube2，O2The gas flow is 20L/min, the oxygen blowing is stopped after the blowing time reaches 35min, a small amount of molten steel and slag are respectively extracted by a sampler after the mixture is kept stand for 10min, the mixture is cooled and crushed into small steel particles and slag particles, the silicon content of the steel particles and the FeO content of the slag particles are respectively determined by chemical analysis, when the molar ratios of Ca/Si are 1.4 and 1.8, the Si content of the steel is respectively 0.009 percent and 0.0062 percent, and the FeO content of the slag phase is respectively 5 percent and 4.7 percent.
After Si and C are removed, adding zinc particles into the molten steel through a corundum tube, wherein the adding amount of the zinc particles is 0.1 percent and 0.15 percent of the mass of the molten steel, inserting the corundum tube into the bottom of the molten steel, preventing the zinc from rapidly escaping from the molten steel after gasification, increasing the reaction time of the zinc and the molten steel, waiting for 10min after adding the zinc particles, extracting a small amount of molten steel through a sampler after the components of the molten steel are completely uniform, cooling and crushing the molten steel into small steel particles, and measuring the sulfur content of the steel particles by adopting a carbon-sulfur analyzer. When the addition amount of zinc particles is 0.1% and 0.15% of the mass of molten steel, the sulfur content of the molten steel is 0.0028% and 0.0022%, respectively.
Molten steel from which S is removed with CO2Adding ZnO powder reagent as carrier gas into molten steel via corundum tube, stirring to disperse ZnO in molten steel, wherein the addition amount of ZnO is 0.6%, 0.7% of molten steel mass, and CO2The gas flow is 2L/min, the blowing time is 32min, the still standing is carried out for 10min after the blowing is finished, the formed FeO is ensured to fully react with ZnO and P to form zinc phosphate melt, a small amount of molten steel is extracted by a sampler, the molten steel is cooled and crushed into small steel particles, the phosphorus content of the steel particles is determined by chemical analysis, when the addition amount of ZnO is 0.6 percent of the mass of the molten steel, the phosphorus content of the molten steel is reduced to 0.001 percent, when the addition amount of ZnO is 0.6 percent of the mass of theWhen the amount of the phosphorus in the molten steel is 0.7% of the mass of the molten steel, the phosphorus content in the molten steel is reduced to 0.0006%.
Example 6
Pure iron, ferrosilicon, graphite powder, FeS and an iron phosphide pure chemical reagent are used as raw materials and are completely melted in a medium-frequency induction furnace to prepare molten iron with the silicon content of 0.15 percent, the carbon content of 3.5 percent, the S content of 0.05 percent and the P content of 0.05 percent, the experimental temperature is 1650 ℃, and the mass of the molten iron is 20 kg.
After the molten iron is completely melted, adding a quicklime pure chemical reagent as a desiliconization agent, wherein the Ca/Si molar ratio is 2.0, and simultaneously blowing O to the bottom of the molten iron through a corundum tube2，O2The gas flow is 20L/min, blowing time reaches 35min, then oxygen blowing is stopped, after standing for 10min, a small amount of molten steel and slag are respectively extracted by a sampler, after cooling, the molten steel and the slag are crushed into small steel particles and slag particles, and chemical analysis is adopted to respectively determine the silicon content of the steel particles and the FeO content of the slag particles, wherein the Si content of the steel is 0.005%, and the FeO content of the slag phase is 4.2%.
After Si and C are removed, adding zinc particles into the molten steel through a corundum tube, wherein the adding amount of the zinc particles is 0.2 percent of the mass of the molten steel, inserting the corundum tube into the bottom of the molten steel, preventing the zinc from rapidly escaping from the molten steel after gasification, increasing the reaction time of zinc and the molten steel, waiting for 10min after adding the zinc particles, extracting a small amount of molten steel through a sampler after the components of the molten steel are completely uniform, cooling and crushing the molten steel into small steel particles, and measuring the sulfur content of the steel particles by adopting a carbon-sulfur analyzer. The sulfur content of the molten steel is 0.0013 percent.
Molten steel from which S is removed with CO2Adding ZnO powder reagent as carrier gas into molten steel via corundum tube, stirring to disperse ZnO in molten steel, wherein the addition amount of ZnO is 0.8% of molten steel mass, and CO is added2The gas flow is 2L/min, the blowing time is 28min and 30min, the still standing is carried out for 10min after the blowing is finished, the formed FeO is ensured to fully react with ZnO and P to form zinc phosphate melt, a small amount of molten steel is extracted by a sampler, the molten steel is cooled and crushed into small steel particles, and the phosphorus content of the steel particles is measured by chemical analysis, when the addition of ZnO is 0.6 percent of the mass of the molten steel, the phosphorus content of the molten steel is reduced to 0.0014 percent, and when the addition of ZnO is 0.7 percent of the mass of the molten steel, the phosphorus content of the molten steel is reduced to 0.0006 percent.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.
Claims (10)
1. A deep sulfur and phosphorus removal method for less-slag steel making is characterized by comprising the following steps:
step 1, slagging, desiliconizing and decarbonizing stages;
adding an alkaline flux into molten iron, reducing FeO formed at the initial slagging stage by CO gas generated in a decarburization period, and separating molten slag from molten steel after desiliconization and decarburization are finished to obtain low-alkalinity and low-iron steel slag and molten steel;
step 2, reduction and desulfurization;
with N2Spraying a desulfurizing agent Zn from the bottom of the molten steel for carrier gas, reacting the Zn with sulfur in the molten steel to generate ZnS, and separating the ZnS to obtain desulfurized molten steel;
step 3, carrying out deep decarburization and deep dephosphorization on the desulfurized molten steel;
deep decarburization is carried out on the molten steel by using a decarburization oxidant before dephosphorization; when the carbon content in the molten steel is less than 0.5%, spraying CO containing ZnO powder from the bottom of the molten steel2Gas, decarburization and dephosphorization are carried out simultaneously, and a dephosphorization product is separated to obtain a zinc phosphate melt and a dephosphorized molten steel, wherein C in the dephosphorized molten steel is less than 0.25 percent, and P in the dephosphorized molten steel is less than 0.002 percent;
step 4, reducing the zinc phosphate melt by using solid carbon to obtain metal zinc steam and phosphorus steam, and separating the metal zinc from the phosphorus steam after condensing by using the different boiling points of the metal zinc steam and the phosphorus steam; and (4) recycling the phosphorus, and returning the metal zinc as a desulfurizing agent to the step (2) for recycling.
2. The method for deeply removing sulfur and phosphorus in the less-slag steelmaking according to claim 1, wherein in the step 2, the mass ratio of Zn to S is 1.2-1.5, and ZnS and molten steel are separated by slag skimming;
and S in the desulfurized molten steel is less than 0.003 percent.
3. The method for deeply removing sulfur and phosphorus in less-slag steelmaking according to claim 1, wherein in step 2, ZnS is oxidized by pure oxygen to obtain SO3Gas and ZnO, SO3And (3) absorbing the gas by water, and then preparing sulfuric acid, wherein ZnO is used as a dephosphorizing agent and returns to the step 3 for recycling.
4. The method for deeply removing sulfur and phosphorus in steel making with less slag as claimed in claim 1, wherein in step 4, the generated CO gas is converted into CO after being used as fuel for combustion2Flue gas, CO2The flue gas is used as a decarburization oxidant and returned to the step 3 for recycling.
5. The method for deeply removing sulfur and phosphorus in steel making with less slag as claimed in claim 1, wherein in step 3, the decarbonizing oxidant is CO2，CO2Blowing in CO from the bottom of the converter through an oxygen lance2The molar ratio of (0.5Si + C) is 1 to 1.1.
6. The method for deeply removing sulfur and phosphorus in steel making with less slag as claimed in claim 1, wherein in step 3, the decarbonizing oxidant is O2，O2Blowing in CO from the bottom of the converter through an oxygen lance2The molar ratio of (0.5Si + C) is 0.5 to 0.55.
7. The method for deeply removing sulfur and phosphorus in less-slag steelmaking according to claim 5 or 6, wherein in the step 3, the mass ratio of ZnO/P is 4-4.5, and the carrier gas of ZnO powder is CO2The molar ratio of/P is 2.6-3.0.
8. The method for deeply removing sulfur and phosphorus in the less-slag steel-making process according to claim 1, wherein in the step 1, the alkaline flux is quicklime, the alkalinity of the steel slag in the low-alkalinity and low-iron steel slag is 1.4-2.0, and the content of FeO is 5-10%; the Si content in the molten steel is lower than 0.01 percent, and the C content in the molten steel is lower than 0.25 percent.
9. The method for deeply removing sulfur and phosphorus in less-slag steelmaking according to claim 1, wherein in the step 4, the reduction is carried out in a ladle at a temperature of 1100-1500 ℃.
10. The method for deeply removing sulfur and phosphorus in less-slag steelmaking according to claims 1 to 9, wherein the low-alkalinity and low-iron steel slag in the step 1 is used for preparing building raw materials.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114807483A (en) * | 2022-04-22 | 2022-07-29 | 中国恩菲工程技术有限公司 | Smelting method and smelting device for high-phosphorus iron ore |
| CN114854924A (en) * | 2022-04-22 | 2022-08-05 | 中国恩菲工程技术有限公司 | Method and device for preparing low-phosphorus molten iron from high-phosphorus iron ore |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0726317A (en) * | 1993-07-07 | 1995-01-27 | Sumitomo Metal Ind Ltd | Method for classifying zinc-containing dust by molten iron pre-treatment |
| JP2005089794A (en) * | 2003-09-16 | 2005-04-07 | Nippon Steel Corp | Method for effectively utilizing iron-making dust as resource |
| CN104694819A (en) * | 2015-03-27 | 2015-06-10 | 山东钢铁股份有限公司 | Production method for low-carbon low-silicon steel |
| CN105177217A (en) * | 2015-08-20 | 2015-12-23 | 山东西王特钢有限公司 | Process for reducing steel slag quantity during converter smelting |
| CN109280731A (en) * | 2018-10-24 | 2019-01-29 | 北京科技大学 | The method of the high phosphorus hot metal production steel of converter terminal P≤0.01% is smelted using few slag charge |
-
2020
- 2020-03-30 CN CN202010241283.4A patent/CN111471832B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0726317A (en) * | 1993-07-07 | 1995-01-27 | Sumitomo Metal Ind Ltd | Method for classifying zinc-containing dust by molten iron pre-treatment |
| JP2005089794A (en) * | 2003-09-16 | 2005-04-07 | Nippon Steel Corp | Method for effectively utilizing iron-making dust as resource |
| CN104694819A (en) * | 2015-03-27 | 2015-06-10 | 山东钢铁股份有限公司 | Production method for low-carbon low-silicon steel |
| CN105177217A (en) * | 2015-08-20 | 2015-12-23 | 山东西王特钢有限公司 | Process for reducing steel slag quantity during converter smelting |
| CN109280731A (en) * | 2018-10-24 | 2019-01-29 | 北京科技大学 | The method of the high phosphorus hot metal production steel of converter terminal P≤0.01% is smelted using few slag charge |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114807483A (en) * | 2022-04-22 | 2022-07-29 | 中国恩菲工程技术有限公司 | Smelting method and smelting device for high-phosphorus iron ore |
| CN114854924A (en) * | 2022-04-22 | 2022-08-05 | 中国恩菲工程技术有限公司 | Method and device for preparing low-phosphorus molten iron from high-phosphorus iron ore |
| CN114854924B (en) * | 2022-04-22 | 2023-12-01 | 中国恩菲工程技术有限公司 | Method and device for preparing low-phosphorus molten iron from high-phosphorus iron ore |
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