CN112746141A - Method for preparing phosphorus-rich slag by separating iron and phosphorus from steel slag and reoxidizing - Google Patents

Method for preparing phosphorus-rich slag by separating iron and phosphorus from steel slag and reoxidizing Download PDF

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CN112746141A
CN112746141A CN202110156318.9A CN202110156318A CN112746141A CN 112746141 A CN112746141 A CN 112746141A CN 202110156318 A CN202110156318 A CN 202110156318A CN 112746141 A CN112746141 A CN 112746141A
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phosphorus
slag
furnace
iron
steel slag
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袁章福
刘克
施春红
张岩岗
廖亮
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University of Science and Technology Beijing USTB
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University of Science and Technology Beijing USTB
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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B11/00—Making pig-iron other than in blast furnaces
    • C21B11/10—Making pig-iron other than in blast furnaces in electric furnaces
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B3/00—General features in the manufacture of pig-iron
    • C21B3/02—General features in the manufacture of pig-iron by applying additives, e.g. fluxing agents
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B3/00—General features in the manufacture of pig-iron
    • C21B3/04—Recovery of by-products, e.g. slag
    • C21B3/06—Treatment of liquid slag
    • 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
    • C21C1/00—Refining of pig-iron; Cast iron
    • C21C1/02—Dephosphorising or desulfurising
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Carbon Steel Or Casting Steel Manufacturing (AREA)

Abstract

The invention provides a method for preparing phosphorus-rich slag by separating iron from phosphorus in steel slag and reoxidizing the iron and the phosphorus, which comprises the following steps of: s1: charging molten steel slag discharged by converter steelmaking into a closed direct current electric furnace, and simultaneously adding a reducing agent and a modifier to obtain high-phosphorus molten iron; s2: the high-phosphorus molten iron obtained by reduction in S1 is loaded into an induction smelting furnace, oxygen is blown in while fluxing agent and cooling agent are added, inert gas is blown in from the furnace bottom for stirring, the separation of iron and phosphorus from steel slag is completed, and meanwhile, phosphorus-rich slag is obtained. The invention has important significance for recycling metallurgical bulk solid waste resources and saving energy.

Description

Method for preparing phosphorus-rich slag by separating iron and phosphorus from steel slag and reoxidizing
[ technical field ] A method for producing a semiconductor device
The invention relates to the technical field of ferrous metallurgy, in particular to a method for preparing phosphorus-rich slag by separating iron from phosphorus from steel slag and reoxidizing the iron and the phosphorus.
[ background of the invention ]
Along with the continuous rising of the steel yield, the amount of the steel slag discharged correspondingly also continuously increases. The crude steel yield of the Chinese continental is 9.963 hundred million tons in 2019, accounts for 53.3 percent of the global crude steel yield, and is the first place of the world. About 15% of steel slag is produced per ton of converter steel, the quantity of the steel slag per year is about 1.2 hundred million tons, the accumulated stock exceeds 18 million tons by 2019 years according to incomplete statistics, and the effective utilization rate of the traditional Chinese steel slag is only about 30%, so that resources are wasted, a large amount of cultivated land is occupied, and environmental pollution is caused.
The internal circulation of steel smelting and the preparation of building materials are two main approaches for the conversion and utilization of the current steel slag: in the aspect of internal circulation, harmful phosphorus elements in the steel slag limit the large-scale efficient conversion and utilization of the steel slag; in the aspect of preparing building material raw materials, harmful phosphorus elements and unstable iron-containing substances are equal, so that the building material raw materials have the name of 'poor cement clinker'.
A large amount of high-temperature molten steel slag is generated in the converter steelmaking process, the temperature is as high as about 1600 ℃, the specific heat capacity of the slag is about 1.2J/(kg DEG C), and the sensible heat contained in each ton of slag is about equivalent to the heat generated after 50-70 kg of standard coal is completely combusted. If the sensible heat of the part of the slag can be recovered, the total energy saving amount can reach 600 ten thousand tons of standard coal. Because the sensible heat utilization rate of the steel slag is low in cost problem, huge waste of heat energy is caused, the sensible heat of the steel slag is fully utilized, and the method has important significance for realizing efficient utilization of resources and energy and reducing energy conservation and consumption reduction of iron and steel enterprises.
High phosphorus ore is an iron ore resource which is extremely difficult to treat, the reserves of 30-50 hundred million tons are reserved in China, and the high phosphorus ore is mainly distributed in regions such as Hunan, Hubei, Guangxi, Guizhou and the like. The iron ore contains high phosphorus (0.4-1.8%) and low iron grade (35-50%), and the phosphorus in the iron ore exists in collophanite and is mixed with oolitic green mud stone rich in iron oxide to form an oolitic grain structure which is concentric, layered and alternated. Due to the unique oolitic grain structure in the high phosphorus ore and the complex imbedding relationship between the phosphorus-containing gangue mineral and the iron mineral, when the high phosphorus ore is directly treated by conventional ore dressing methods such as reselection, magnetic separation, flotation and the like, although iron ore concentrate with a certain iron grade can be obtained, the effective reduction of the phosphorus content in the iron ore concentrate is very difficult, and when the methods such as magnetizing roasting, chemical leaching and the like are adopted to treat the oolitic iron ore for improving iron and dephosphorizing, the problems of poor dephosphorization effect, poor product quality, low iron, high cost, large environmental pollution and the like also exist.
As a reduction process of slag, various forms such as a converter type, an electric furnace type, and a shaft furnace type have been proposed. Wherein, the invention selects the closed direct current electric furnace to reduce the steel slag and the high phosphate ore. The process is developed by MINTEK in south Africa, is mainly used for manufacturing ferroalloy, has no air invasion unlike a dissolving type universal electric furnace, and does not form a filling layer of solid raw materials like a submerged arc furnace of a universal reduction electric furnace. The sealed furnace has the following characteristics: 1) high reduction rate due to the reduction of oxygen potential in the furnace; 2) high thermal efficiency due to low exhaust gas flow; 3) the low flow rate gas in the furnace can make the powder raw material be fed upwards. In addition, the dc electric furnace has features of promoting the flow in the slag, reducing the electrode strength, and facilitating the operation.
In view of the above, the invention provides a method for preparing phosphorus-rich slag by separating iron from phosphorus from steel slag and reoxidizing the iron and the phosphorus.
[ summary of the invention ]
In view of the above, the invention provides a method for preparing phosphorus-rich slag by separating iron from phosphorus from steel slag and reoxidizing the iron and the phosphorus, so as to overcome the problems of difficulty in recycling steel slag, recycling waste heat of steel slag, developing and utilizing high phosphorus ore and the like in the prior art.
In one aspect, the invention provides a method for preparing phosphorus-rich slag by separating iron from phosphorus in steel slag and reoxidizing the iron and the phosphorus, wherein the method comprises the following steps:
s1: charging molten steel slag discharged by converter steelmaking into a closed direct current electric furnace, and simultaneously adding a reducing agent and a modifier to obtain high-phosphorus molten iron;
s2: and (3) charging the high-phosphorus molten iron obtained by reduction in the step (S1) into an induction smelting furnace, blowing oxygen, adding a fluxing agent and a cooling agent, blowing inert gas from the bottom of the furnace, stirring, separating iron and phosphorus from the steel slag, and simultaneously obtaining phosphorus-rich slag.
As to the above-mentioned aspect and any possible implementation manner, there is further provided an implementation manner, where the S1 specifically includes:
s11: charging molten iron into a closed direct current furnace and leaving a layer of reducing slag;
s12: charging 1500-1700 ℃ molten steel slag discharged from converter steelmaking into a heat preservation furnace, and slowly adding the molten steel slag into a closed direct current electric furnace in an inclined manner;
s13: continuously feeding a reducing agent and a modifying agent into a closed direct current electric furnace through a raw material feeding pipe arranged on a furnace cover;
s14: and (3) discharging reducing slag from the slag outlet when the reduction treatment in the closed direct current furnace is finished, and discharging the high-phosphorus molten iron obtained by reduction from the iron outlet when the molten iron liquid level approaches the position of the slag outlet along with the increase of the molten iron.
The above aspects and any possible implementation manners further provide an implementation manner, wherein the S13 is calculated according to the grades of the steel slag and the high phosphate ore, and the ratio of carbon to iron is in the range of 150-300 kg/tFe; the addition amount of the high phosphorus ore is 1-50% of the total mass of the steel slag, and SiO2The addition amount of Al accounts for 15-25% of the total mass of the steel slag2O3The adding amount is 5-15% of the total mass of the steel slag.
The above aspect and any possible implementation manner further provide an implementation manner, wherein the reducing agent is coke, and the modifier comprises high phosphorus ore and SiO2And Al2O3The high phosphorus ore contains 70% of hematite, 2.5% of apatite and 10% of quartz, 40-50% of iron element and 0.4-1% of phosphorus element.
The above aspects and any possible implementation manners further provide an implementation manner that the target composition of the steel slag after reduction in S14 is alkalinity (CaO)/(SiO)2) 1.0 to 1.2, basicity (Al)2O3) 10-12%, and the reduced steel slag has the same components as the blast furnace slag.
As to the above-mentioned aspect and any possible implementation manner, there is further provided an implementation manner, where the S2 specifically includes:
s21: charging the high-phosphorus molten iron obtained by reduction into induction meltingIn the furnace, the furnace is then charged from the lance at 30-60 Nm3Blowing oxygen at a speed of/h to carry out dephosphorization treatment;
s22, adding fluxing agent and cooling agent from the upper part of the induction melting furnace;
s23 blowing 2-10 Nm from the porous plug at the bottom of the induction melting furnace3And/h argon is used as stirring gas to obtain the phosphorus-rich slag.
The above aspects and any possible implementations further provide an implementation where the flux includes quicklime, dolomite, and silica sand.
The above aspect and any possible implementation manner further provide an implementation manner, and the furnace temperature during stirring in S23 is set to be 1200-1600 ℃.
The above aspects and any possible implementation manners further provide an implementation manner, and the slag obtained by dephosphorization in S23 is 10-20% of P2O5And the dephosphorized molten iron is less than 0.1 percent, and the molten iron is returned to the converter for steelmaking.
Compared with the prior art, the invention can obtain the following technical effects:
1. the closed direct current electric furnace has the characteristics of low oxygen potential in the furnace, high reduction rate, low exhaust gas volume, high heat efficiency, capability of enabling powder raw materials to be fed upwards by low-flow-rate gas in the furnace, promotion of internal flow of slag, reduction of electrode strength, easiness in operation and the like;
2. in the closed DC electric furnace, the steel slag contains a large amount of alkaline substances such as calcium oxide, so that the steel slag can generate part of CO after reduction2Absorbing gas to absorb CO2The fixing function is achieved;
3. the invention has important significance for recycling metallurgical bulk solid waste resources and saving energy.
Of course, it is not necessary for any one product in which the invention is practiced to achieve all of the above-described technical effects simultaneously.
[ description of the drawings ]
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
FIG. 1 is a flow chart of the preparation of iron and phosphorus re-oxidation separated from steel slag according to one embodiment of the present invention;
fig. 2 is a system schematic diagram of a closed dc electric furnace according to an embodiment of the present invention;
fig. 3 is a schematic system diagram of a smelting induction furnace according to one embodiment of the present invention.
Wherein, in the figure:
1-blast furnace, 2-molten iron pretreatment device, 3-converter, 4-slag holding furnace, 5-tailings recovery device, 6-induction smelting furnace, 7-closed direct current electric furnace, 8-air burner, 9-oxygen nozzle, 10-feeder, 11-slag outlet, 12-tap hole, 13-holding furnace, 14-electrode, 15-sliding sleeve, 16-high temperature slag inlet, 17-oxygen spray gun and 18-argon bottom blowing porous brick.
[ detailed description ] embodiments
For better understanding of the technical solutions of the present invention, the following detailed descriptions of the embodiments of the present invention are provided with reference to the accompanying drawings.
It should be understood that the described embodiments are only some embodiments of the invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the examples of the present invention and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
The invention provides a method for preparing phosphorus-rich slag by separating iron from phosphorus in steel slag and reoxidizing the iron and the phosphorus, which comprises the following steps of:
s1: charging molten steel slag discharged by converter steelmaking into a closed direct current electric furnace, and simultaneously adding a reducing agent and a modifier to obtain high-phosphorus molten iron;
s2: and (3) charging the high-phosphorus molten iron obtained by reduction in the step (S1) into an induction smelting furnace, blowing oxygen, adding a fluxing agent and a cooling agent, blowing inert gas from the bottom of the furnace, stirring, separating iron and phosphorus from the steel slag, and simultaneously obtaining phosphorus-rich slag.
The S1 specifically includes:
s11: charging molten iron into a closed direct current furnace and leaving a layer of reducing slag;
s12: charging 1500-1700 ℃ molten steel slag discharged from converter steelmaking into a heat preservation furnace, and slowly adding the molten steel slag into a closed direct current electric furnace in an inclined manner;
s13: continuously feeding a reducing agent and a modifying agent into a closed direct current electric furnace through a raw material feeding pipe arranged on a furnace cover;
s14: and (3) discharging reducing slag from the slag outlet when the reduction treatment in the closed direct current furnace is finished, and discharging the high-phosphorus molten iron obtained by reduction from the iron outlet when the molten iron liquid level approaches the position of the slag outlet along with the increase of the molten iron.
The S13 is calculated according to the grades of the steel slag and the high phosphorus ore, and the proportion range of carbon and iron is 150-300 kg/tFe; the addition amount of the high phosphorus ore is 1-50% of the total mass of the steel slag, and SiO2The addition amount of Al accounts for 15-25% of the total mass of the steel slag2O3The adding amount is 5-15% of the total mass of the steel slag. The reducing agent is coke, and the modifier comprises high phosphorus ore and SiO2And Al2O3The high phosphorus ore contains 70% of hematite, 2.5% of apatite and 10% of quartz, 40-50% of iron element and 0.4-1% of phosphorus element. The target composition of the steel slag after reduction in S14 is alkalinity (CaO)/(SiO)2) 1.0 to 1.2, basicity (Al)2O3) 10-12%, and the reduced steel slag has the same components as the blast furnace slag.
The S2 specifically includes:
s21: charging the high-phosphorus molten iron obtained by reduction into an induction smelting furnace, and blowing oxygen from a spray gun at the speed of 30-60 Nm3/h to perform dephosphorization treatment;
s22, adding fluxing agent and cooling agent from the upper part of the induction melting furnace;
and S23, blowing argon gas of 2-10 Nm3/h from a porous plug at the bottom of the induction melting furnace as stirring gas to obtain phosphorus-rich slag.
The fluxing agent comprises quicklime, dolomite and silica sand. And the furnace temperature is set to be 1200-1600 ℃ during stirring in the S23. The slag obtained by dephosphorization in the S23 is 10-20% of P2O5And the dephosphorized molten iron is less than 0.1 percent, and the molten iron is returned to the converter for steelmaking.
The method is carried out based on the following system, as shown in figure 1, the system comprises a blast furnace 1, a molten iron pretreatment device 2, a converter 3, a molten slag holding furnace 4, an induction smelting furnace 6, a closed direct current electric furnace 7 and a tailings recovery device 5, wherein the blast furnace 1 is connected with the converter 3 through the molten iron pretreatment device 2, one end of the molten slag holding furnace 4 is simultaneously connected with the converter 3 and the molten iron pretreatment device 2, the other end of the molten slag holding furnace is connected with the closed direct current electric furnace 7, the bottom of the closed direct current electric furnace 7 is connected with the induction smelting furnace 6, the bottom of the induction smelting furnace 6 is connected with the converter 3, and the molten slag holding furnace 4 and the induction smelting furnace 6 are both connected with the tailings recovery.
As shown in fig. 2, the closed dc electric furnace 7 includes a sealed furnace body, an electrode 14 and a holding furnace 13, one end of the holding furnace 13 is connected to the top of the sealed furnace body, the other end is connected to the slag holding furnace 4, one end of the electrode 14 is arranged in the sealed furnace body, the other end is connected to the power supply outside the sealed furnace body, a feeder 10 is further arranged above the sealed furnace body, an iron outlet 12 and a slag outlet 11 are respectively arranged on two sides of the sealed furnace body, the iron outlet 12 is 200mm lower than the slag outlet 11, the iron outlet 12 is connected to the induction melting furnace 6, an air burner and an oxygen port are arranged on the holding furnace 13, the air burner is connected to the air burner 8, the oxygen port is connected to the oxygen nozzle 9, a high-temperature slag inlet is further arranged above the holding furnace 13, and the high-temperature slag inlet. And a sliding sleeve 15 is also arranged between the slag holding furnace 4 and the tailings recovery device 5.
As shown in fig. 3, a connecting oxygen lance 17 and a feeder 10 are arranged above the induction smelting furnace 6, and an argon bottom-blowing perforated brick 18 is arranged at the bottom of the induction smelting furnace 6.
The smelting process of the method is as follows:
(1) charging 1500-1700 ℃ molten steel slag discharged from the steel making of the converter 3 into a closed direct current electric furnace 7, and simultaneously charging a carbonaceous reducing agent and high phosphorus ore and SiO serving as a modifier2And Al2O3Adding the mixture into a reducing furnace, wherein the carbon reducing agent is calculated according to the grades of steel slag (TFe) and high phosphorus ore, the proportion range of carbon and iron is 150-300 kg/tFe, the addition amount of the high phosphorus ore is 1-50% of the total mass of the steel slag, and SiO2The addition amount of Al accounts for 15-25% of the total mass of the steel slag2O3The adding amount is 5-15% of the total mass of the steel slag.
(2) The high-phosphorus molten iron obtained by the reduction in the above steps is charged into an induction smelting furnace 6, then oxygen is blown in from a lance, and simultaneously quicklime, dolomite and silica sand are added from above as fluxing agents, and iron ore is used as a coolant. Argon gas was blown as a stirring gas from a porous plug at the bottom of the furnace.
The closed DC electric furnace 7 has a low oxygen potential in the furnace to produce a high reduction ratio, a low gas displacement to produce a high heat efficiency, and a low gas flow rate in the furnace to allow the powder raw material to be fed upward. A holding furnace 13 for storing slag is provided above the closed DC electric furnace 7. The iron content of the high phosphorus ore is 40-50%, and the high phosphorus ore mainly exists in a hematite form; phosphorus content is 0.4-1%, and exists mainly in apatite form; the other main gangue is quartz, and the content is 10-15%. The carbonaceous reducing agent is coke.
The target composition of the reduced steel slag is alkalinity (CaO)/(SiO)2)＝1.0～1.2，(Al2O3) 10-12% of the total amount of the slag, which is the same as that of the blast furnace 1 slag. The spray gun in the smelting furnace is 30-60 Nm3Oxygen was blown in at a rate of/h. Blowing 2-10 Nm from a porous plug at the bottom of the furnace3Argon/h as stirring gas. The temperature in the induction melting furnace 6 is set to be 1200-1600 ℃. Dephosphorized molten iron [ P ]]Less than 0.1% of phosphorus-rich slag (P) obtained by returning to converter 3 for steelmaking and dephosphorizing2O5) 10-20% of the total amount of the phosphate fertilizer is used for producing high-phosphate fertilizer.
Example 1
Charging 1400 ℃ molten steel slag discharged from converter steelmaking into a closed direct current electric furnace, and simultaneously charging a carbonaceous reducing agent and high phosphorus ore and SiO serving as modifiers2And Al2O3Adding into a reducing furnace, wherein the coke is calculated according to the grades of the steel slag (TFe) and the high phosphorus ore, the proportion range of the carbon and the iron is 175kg/tFe, the adding amount of the high phosphorus ore is 15 percent of the total mass of the steel slag, and SiO is2The addition amount of Al accounts for 25 percent of the total mass of the steel slag2O3The adding amount is 10 percent of the total mass of the steel slag. The reduced steel slag is the same as the blast furnace slag, the high-phosphorus molten iron obtained by reduction is filled into an induction smelting furnace, and then a spray gun in the furnace is used for spraying 30Nm3Oxygen is blown in at a speed of/h, and simultaneously, quicklime, dolomite and silica sand are added from the top as fluxing agents, and iron ore is used as a cooling agent. In addition, 4Nm of air was blown from a porous plug at the bottom of the furnace3Argon gas/h was used as the stirring gas, and the furnace temperature was set at 1300 ℃.
Example 2
Charging 1450 deg.C molten steel slag discharged from converter steel-making into closed DC electric furnace, and simultaneously charging carbonaceous reducing agent and high phosphorus ore and SiO as modifier2And Al2O3Adding into a reducing furnace, wherein the coke is calculated according to the grades of steel slag (TFe) and high phosphorus ore, the proportion range of carbon and iron is 250kg/tFe, the addition amount of the high phosphorus ore is 20 percent of the total mass of the steel slag, and SiO2The addition amount of Al accounts for 21 percent of the total mass of the steel slag2O3The adding amount is 12 percent of the total mass of the steel slag. The reduced steel slag is the same as the blast furnace slag, the high-phosphorus molten iron obtained by reduction is filled into an induction smelting furnace, and then a spray gun in the furnace is used for spraying molten iron with the speed of 40Nm3Oxygen is blown in at a speed of/h, and simultaneously, quicklime, dolomite and silica sand are added from the top as fluxing agents, and iron ore is used as a cooling agent. Further, 6Nm of gas was blown from a porous plug at the bottom of the furnace3Argon gas/h was used as the stirring gas and the furnace temperature was set at 1400 ℃.
Example 3
Charging 1500 ℃ molten steel slag discharged from converter steelmaking into a closed direct current electric furnace, and simultaneously charging a carbonaceous reducing agent and high phosphorus ore and SiO serving as modifiers2And Al2O3Adding into a reducing furnace, wherein the coke is calculated according to the grades of steel slag (TFe) and high phosphorus ore, the proportion range of carbon and iron is 275kg/tFe, the addition amount of the high phosphorus ore is 25 percent of the total mass of the steel slag, and SiO is2The addition amount of Al accounts for 18 percent of the total mass of the steel slag2O3The adding amount is 12 percent of the total mass of the steel slag. The reduced steel slag is the same as the blast furnace slag, the high-phosphorus molten iron obtained by reduction is filled into an induction smelting furnace, and then a spray gun in the furnace is used for spraying at 45Nm3Oxygen is blown in at a speed of/h, and simultaneously, quicklime, dolomite and silica sand are added from the top as fluxing agents, and iron ore is used as a cooling agent. In addition, 7Nm of air was blown through a porous plug at the bottom of the furnace3Argon gas/h was used as a stirring gas, and the furnace temperature was set at 1500 ℃.
Example 4
The 1600 ℃ molten steel slag discharged from converter steelmaking is filled into a closed direct current electric furnace, and simultaneously a carbonaceous reducing agent and high phosphorus ore and SiO used as a modifier are added2And Al2O3Adding into a reducing furnace, wherein the coke is calculated according to the grades of steel slag (TFe) and high phosphorus ore, the proportion range of carbon and iron is 300kg/tFe, the addition amount of the high phosphorus ore is 30 percent of the total mass of the steel slag, and SiO2The addition amount of Al accounts for 15 percent of the total mass of the steel slag2O3The adding amount is 15 percent of the total mass of the steel slag. The reduced steel slag is the same as the blast furnace slag, the high-phosphorus molten iron obtained by reduction is filled into an induction smelting furnace, and then a spray gun in the furnace is used for spraying 55Nm3Oxygen is blown in at a speed of/h, and simultaneously, quicklime, dolomite and silica sand are added from the top as fluxing agents, and iron ore is used as a cooling agent. Further, 8Nm of air was blown from a porous plug at the bottom of the furnace3Argon/h was used as stirring gas and the furnace temperature was set at 1600 ℃.
The method for preparing the phosphorus-rich slag by separating iron from phosphorus from the steel slag and reoxidizing the iron and the phosphorus provided by the embodiment of the application is described in detail above. The above description of the embodiments is only for the purpose of helping to understand the method of the present application and its core ideas; meanwhile, for a person skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.
As used in the specification and claims, certain terms are used to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. This specification and claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. "substantially" means within an acceptable error range, and a person skilled in the art can solve the technical problem within a certain error range to substantially achieve the technical effect. The description which follows is a preferred embodiment of the present application, but is made for the purpose of illustrating the general principles of the application and not for the purpose of limiting the scope of the application. The protection scope of the present application shall be subject to the definitions of the appended claims.
It is also noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a good or system that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such good or system. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a commodity or system that includes the element.
It should be understood that the term "and/or" as used herein is merely one type of association that describes an associated object, meaning that three relationships may exist, e.g., a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.
The foregoing description shows and describes several preferred embodiments of the present application, but as aforementioned, it is to be understood that the application is not limited to the forms disclosed herein, but is not to be construed as excluding other embodiments and is capable of use in various other combinations, modifications, and environments and is capable of changes within the scope of the application as described herein, commensurate with the above teachings, or the skill or knowledge of the relevant art. And that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the application, which is to be protected by the claims appended hereto.

Claims (10)

1. A method for preparing phosphorus-rich slag by separating iron from phosphorus in steel slag and reoxidizing the iron and the phosphorus is characterized by comprising the following steps of:
s1: charging molten steel slag discharged by converter steelmaking into a closed direct current electric furnace, and simultaneously adding a reducing agent and a modifying agent to obtain high-phosphorus molten iron;
s2: and (3) charging the high-phosphorus molten iron obtained by reduction in the step (S1) into an induction smelting furnace, blowing oxygen, adding a fluxing agent and a cooling agent, blowing inert gas from the bottom of the furnace, stirring, separating iron and phosphorus from the steel slag, and simultaneously obtaining phosphorus-rich slag.
2. The method according to claim 1, wherein the S1 specifically includes:
s11: charging molten iron into a closed direct current furnace and leaving a layer of reducing slag;
s12: charging 1500-1700 ℃ molten steel slag discharged from converter steelmaking into a heat preservation furnace, and slowly adding the molten steel slag into a closed direct current electric furnace in an inclined manner;
s13: continuously feeding a reducing agent and a modifying agent into a closed direct current electric furnace through a raw material feeding pipe arranged on a furnace cover;
s14: and (3) discharging reducing slag from the slag outlet when the reduction treatment in the closed direct current furnace is finished, and discharging the high-phosphorus molten iron obtained by reduction from the iron outlet when the molten iron liquid level approaches the position of the slag outlet along with the increase of the molten iron.
3. The method of claim 2, wherein the reducing agent is coke and the modifier comprises a high phosphorus ore, SiO2And Al2O3Said S13 being based on steel slag and high phosphorus ore gradeCalculating that the ratio range of carbon to iron is 150-300 kg/tFe; the addition amount of the high phosphorus ore is 1-50% of the total mass of the steel slag, and SiO2The addition amount of Al accounts for 15-25% of the total mass of the steel slag2O3The adding amount is 5-15% of the total mass of the steel slag.
4. The method of claim 2, wherein the high phosphate ore contains 70% hematite, 2.5% apatite and 10% quartz, 40-50% iron element and 0.4-1% phosphorus element.
5. The method of claim 2, wherein the target composition of the steel slag after reduction in S14 is alkalinity (CaO)/(SiO)2) 1.0 to 1.2, basicity (Al)2O3) 10-12%, and the reduced steel slag has the same components as the blast furnace slag.
6. The method according to claim 1, wherein the S2 specifically includes:
s21: charging the high-phosphorus molten iron obtained by reduction into an induction smelting furnace, and then feeding the molten iron into a spray gun at a speed of 30-60 Nm3Blowing oxygen at a speed of/h to carry out dephosphorization treatment;
s22, adding fluxing agent and cooling agent from the upper part of the induction melting furnace;
s23 blowing 2-10 Nm from the porous plug at the bottom of the induction melting furnace3And/h argon is used as stirring gas to obtain the phosphorus-rich slag.
7. The method of claim 6, wherein the fluxing agent comprises quicklime, dolomite, and silica sand.
8. The method of claim 6, wherein the coolant is iron ore.
9. The method according to claim 6, wherein the furnace temperature during the stirring in S23 is set to be 1200-1600 ℃.
10. The method according to claim 6, wherein the slag obtained by dephosphorizing in S23 is 10-20% P2O5And the dephosphorized molten iron is less than 0.1 percent, and the molten iron is returned to the converter for steelmaking.
CN202110156318.9A 2021-02-04 2021-02-04 Method for preparing phosphorus-rich slag by separating iron and phosphorus from steel slag and reoxidizing Pending CN112746141A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TWI812069B (en) * 2021-06-18 2023-08-11 日商杰富意鋼鐵股份有限公司 Oxygen blast furnace and operation method of oxygen blast furnace

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TWI812069B (en) * 2021-06-18 2023-08-11 日商杰富意鋼鐵股份有限公司 Oxygen blast furnace and operation method of oxygen blast furnace

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