CN114574641B - Method for smelting medium-low carbon ferromanganese - Google Patents
Method for smelting medium-low carbon ferromanganese Download PDFInfo
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- CN114574641B CN114574641B CN202210201241.7A CN202210201241A CN114574641B CN 114574641 B CN114574641 B CN 114574641B CN 202210201241 A CN202210201241 A CN 202210201241A CN 114574641 B CN114574641 B CN 114574641B
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B5/00—Making pig-iron in the blast furnace
- C21B5/008—Composition or distribution of the charge
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D3/00—Pig or like casting
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F9/00—Making metallic powder or suspensions thereof
- B22F9/02—Making metallic powder or suspensions thereof using physical processes
- B22F9/06—Making metallic powder or suspensions thereof using physical processes starting from liquid material
- B22F9/08—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying
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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
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/30—Regulating or controlling the blowing
- C21C5/35—Blowing from above and through the bath
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C1/00—Making non-ferrous alloys
- C22C1/02—Making non-ferrous alloys by melting
- C22C1/03—Making non-ferrous alloys by melting using master alloys
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C22/00—Alloys based on manganese
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- 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
Abstract
The invention relates to a method for smelting medium-low carbon ferromanganese, which further reduces the smelting cost of the medium-low carbon ferromanganese by arranging a blast furnace-converter flow, and minimizes the corrosion to equipment in the converter smelting process by blowing in the mixture of carbon dioxide and oxygen in different proportions in multiple directions in the converter flow, and simultaneously reduces the volatilization loss of manganese, so that the quality of the final product is ensured.
Description
Technical Field
The invention belongs to the technical field of alloy smelting, and particularly relates to a method for smelting medium-low carbon ferromanganese.
Background
The electro-silicothermic process, the electric furnace-shaking ladle process and the converter oxygen blowing process are the main process flows for smelting medium-low carbon ferromanganese in the prior art. The electro-silicothermic process is to add silicomanganese alloy, manganese ore and lime into a refining electric furnace, heat and melt the mixture, reduce the manganese in the manganese ore by using the silicomanganese alloy, and finally obtain a qualified product. The traditional process method has the defects of poor heat energy utilization rate, low manganese recovery rate, high production cost and the like. The electric furnace-shaking ladle method is characterized in that preheated manganese ore, lime and liquid manganese-silicon alloy are added into a shaking ladle, the shaking ladle moves horizontally and circularly, a melt and additives are fully mixed and stirred, the furnace burden is melted by means of sensible heat and reaction heat of the furnace burden, and medium and low carbon ferromanganese is obtained by refining and desiliconization. The ladle shaking method is mature and stable, is a relatively reliable production process, but has relatively long process flow and high energy consumption, and the coordination is difficult to grasp because of the linkage coordination of the manganese-silicon furnace, the refining furnace and the ladle shaking, thereby increasing the volatilization loss of manganese. In addition, the slag amount is large (1.2-1.4 t/t iron), and the environmental pollution is serious. During the production by the oxygen blowing method, high-carbon ferromanganese melt is added into a converter for blowing, decarbonization and desilicification, and finally qualified medium-low carbon ferromanganese is produced. Due to the characteristics of converter blowing, no external heat source is needed in the oxygen blowing process, and the decarburization and desilication reaction is maintained mainly by means of oxidation and heat release inside the furnace body. The method can be divided into a high-carbon ferromanganese oxygen blowing method and a manganese-silicon alloy oxygen blowing method according to different production raw materials. In foreign countries, the oxygen blowing method has been put into industrial use in the 1970 s; the reason why the popularization and application are limited in China is mainly as follows: in the process of converter smelting-low-carbon ferromanganese trial production in many domestic ferroalloy enterprises, according to the traditional concept that the higher the temperature is, the more decarburization and manganese oxidation inhibition are facilitated, a high-temperature blowing system is adopted in the smelting process, so that the existing converter smelting process has the defects of high refractory material consumption, serious manganese volatilization loss and extremely low manganese recovery rate (when low-carbon ferromanganese with carbon content of about 0.9wt% is blown, the recovery rate of manganese is even less than 40%)
Albeit CO2Is a weak oxidizing agent, but at high temperatures, CO2Can react with C to form CO, so that CO2Different from stirring gas such as Ar, the stirring gas can participate in stirring to increase the reaction contact area of the gas and elements such as C, si in molten metal, and can react with carbon to play a role in decarburization. Among the numerous reactions occurring in the bath, the majority are exothermic reactions which cause the temperature of the bath to rise continuously, seriously damaging the lining; due to CO2Partial pressure of other gases in the bubble is close to zero for H2、N2When the gas is equivalent to vacuum, H can be made by stirring the molten iron2、N2Diffusion of isogas into CO2In the air bubble, and with CO2The air bubbles are discharged, thereby achieving the purpose of purifying the molten iron. Chinese patent publication CN104294002A converts CO2Is introduced into the production of ferrochrome, but it does not study CO2The blowing proportion and other details of the process are not completely applicable to the preparation of ferromanganese because ferrochrome (which adopts a submerged arc furnace and a converter process) is prepared. Some studies are currently concerned with the utilization of CO2And O2The mixed gas decarbonizes the stainless steel melt (Fe-Cr-C system) to obtain obvious decarbonization and chromium retention effects, but the same does not research CO2The blowing ratio and the like, and the preparation method is not completely applicable to the preparation of ferromanganese because ferrochrome is prepared. At present, CO is also concerned by partial research2And O2A process for smelting ferromanganese by using mixed gas,it is only experimentally investigated for CO2And O2The influence of the overall proportion of the mixed gas on ferromanganese smelting is not researched at all on specific production processes and production details such as raw material setting, basic flow and the like of ferromanganese, and meanwhile, the blowing details of specific positions and the like are not researched at all.
Disclosure of Invention
Based on the defects of the prior art, the invention provides a method for smelting medium-low carbon ferromanganese.
The method is realized by the following technical scheme:
a method of smelting medium-low carbon ferromanganese, the method comprising the steps of:
(1) Blast furnace smelting: the raw materials comprise coke, manganese ore and flux, and the mass ratio of the raw materials is as follows: 76-78 parts of manganese ore, 14-16 parts of coke and 7-8 parts of flux, which are added into a blast furnace according to the sequence of coke-manganese ore-flux, and the blast furnace is set to be 1000-1100 ℃; the tapping period is 90-120 min, and tapping is performed periodically according to the tapping period.
The molten product obtained by the tapping operation of the blast furnace is liquid high-carbon ferromanganese, and the components by weight percentage are as follows: mn:60.0 to 82.0wt%, si: 1.0-2.0 wt%, C:2.0 to 8.0wt%, P: less than or equal to 0.30wt%, S: less than or equal to 0.03wt percent, and the balance of iron and inevitable impurities.
(2) Preparing converter raw materials: adopting a coolant, a silicon-manganese alloy and the liquid high-carbon ferromanganese obtained in the step (1) as raw materials for smelting in the converter for batching, wherein the proportion of the liquid high-carbon ferromanganese is as follows: cooling agent: the silicon-manganese alloy is (64-66): (20 to 22): (12-14) mixing.
(3) Smelting in a converter: weighing the liquid high-carbon ferromanganese obtained in the step (1) according to the proportion set in the step (2), adding into a converter, wherein the adding temperature is 1250-1350 ℃, the converter adopts a top-bottom composite blowing mode, and the top and the bottom are both blown with mixed gas of carbon dioxide and oxygen, wherein the volume ratio of the carbon dioxide to the oxygen in the bottom-blown mixed gas is (5-15) to (85-95); and (3) adding the coolant prepared in the step (2) when the volume ratio of carbon dioxide to oxygen in the top-blown mixed gas is (5-35) and (65-95) when the furnace temperature is increased to 1650-1850 ℃, and blowing for 32-92 min by using the converter.
(4) Discharging by a converter: after the blowing time of the converter is up, adding the silicon-manganese alloy prepared in the step (2) into the converter, and after the liquid alloy melt in the converter is uniform and stable, discharging the smelted liquid alloy from the converter and injecting the smelted liquid alloy into a ladle to obtain liquid medium-low carbon ferromanganese; the medium-low carbon ferromanganese comprises the following components in percentage by weight: mn: 60.0-85.0 wt%, si: less than or equal to 2.5wt%, C:1.0 to 2.9wt%, P: less than or equal to 0.40wt%, S: less than or equal to 0.03wt percent, and the balance of iron and inevitable impurities.
(5) Granulating or casting: adopting the liquid medium-low carbon ferromanganese obtained in the step (4) as a raw material, and producing a medium-low carbon ferromanganese finished product by adopting a molten iron granulation method; or (5) adopting the liquid medium-low carbon ferromanganese obtained in the step (4) as a raw material, and producing a medium-low carbon ferromanganese finished product by adopting a die casting method.
The molten iron granulation method adopts a granulation device, and the obtained liquid medium-low carbon ferromanganese is condensed into compact metal particles with relatively uniform components and properties and low content of oxide inclusions; the die casting method is to pour the obtained liquid medium-low carbon ferromanganese into a die with a certain shape and size, and to obtain a medium-low carbon ferromanganese ingot after the molten iron is solidified and the die is removed.
Preferably, the flux in the step (1) is lime or a mixture of lime and fluorite (generally, the ratio of the lime to the fluorite is 6-15; caO in the lime is more than or equal to 80wt%, and SiO in the lime2Less than 6wt%, P less than 0.05wt%, S less than 0.80wt%, and granularity of 10-60 mm; caF in fluorite2≥75wt％，Al2O3Less than 0.4 to 0.6 percent, caO 0.49 to 0.53 percent, siO2＜26wt％。
Preferably, the coolant in the step (2) is one or more of lime, limestone, dried manganese ore or manganese-iron alloy obtained in the smelting process.
Preferably, the manganese ore in the step (1) contains Mn more than 30wt% and SiO2＜20wt％，Al2O3Less than 7wt%, and Mn/Fe is more than or equal to 3; the granularity of the manganese ore is 10-40 mm.
Preferably, the coke in step (1) has a fixed carbon content of 84wt% or more, an ash content of 14wt%, a moisture content of 6wt% or less, and a particle size of 3 to 20mm.
Preferably, the coolant in the step (2) adopts lime, wherein CaO in the lime is more than or equal to 85wt%, P in the lime is less than or equal to 0.02wt%, and the granularity is 10-50 mm; in the components of the silicon-manganese alloy in the step (2), the Si is 14-17 wt%, the Mn is 60-70 wt%, the C is less than or equal to 2.5wt%, the P is less than or equal to 0.3wt%, the S is less than or equal to 0.05wt%, and the granularity is 5-15 mm.
Preferably, in the step (3), the converter further comprises side blowing, and the side blowing is also a mixed gas of carbon dioxide and oxygen, wherein the volume ratio of the carbon dioxide and the oxygen in the side blowing is (5-15): (85 to 95).
Preferably, the distance between the top-blown oxygen lance and the liquid level of the charge in the step (3) is 350-400 mm.
Preferably, a gas mixing device is arranged between the carbon dioxide gas source, the oxygen gas source and the blowing oxygen lance, a gas flow regulating valve is arranged between the carbon dioxide gas source, the oxygen gas source and the gas mixing device, and a gas flow regulating valve is also arranged between the gas mixing device and the blowing oxygen lance.
Preferably, the molten iron granulation method in the step (5) specifically comprises:
the first step is as follows: and hoisting the steel ladle filled with the molten medium-low carbon ferromanganese to a granulation area, and pouring the liquid medium-low carbon ferromanganese into a tundish through a tipping device.
The second step is that: the liquid medium-low carbon ferromanganese is impacted to the head of the granulating device below through a water gap at the lower part of the tundish, and the medium-low carbon ferromanganese liquid is splashed to finally form liquid granules.
The third step: the medium-low carbon ferromanganese particles are cooled in the granulation tank and then fall to the bottom of the tank.
The fourth step: and (3) the cooled medium-low carbon ferromanganese particles are sent into a storage bin after the processes of dehydration, drying and the like to form a medium-low carbon ferromanganese product. The die casting method in the step (5) comprises the following specific steps:
the first step is as follows: and hoisting the ladle filled with the liquid medium-low carbon ferromanganese to a casting table, and pouring the liquid medium-low carbon ferromanganese into the tundish through a tipping device.
The second step is that: the liquid medium-low carbon ferromanganese flows into the drainage device through a water outlet at the lower part of the tundish.
The third step: and the liquid medium-low carbon ferromanganese is dispersedly injected into the mould through the multi-flow holes of the flow diverter, the mould continuously and circularly rotates, and the solidified medium-low carbon ferromanganese product continuously falls off and then is sent into a storage bin to form the medium-low carbon ferromanganese product.
The invention has the technical effects that:
because the high-carbon ferromanganese is melted at about 1250 ℃, the vapor pressure of manganese is higher, and the volatilization loss of manganese is aggravated when the temperature is too high, the liquid high-carbon ferromanganese can be stable in components and beneficial to top and bottom blowing of the converter after being added into the converter by reasonably setting the converter charging temperature (namely, the charging temperature) of the high-carbon ferromanganese liquid. The blast furnace flow provided by the invention realizes reasonable setting (relatively lower) of the carbon content in the liquid high-carbon ferromanganese, thereby reducing the burden of decarburization in the blowing process; the reasonable setting of the silicon content can avoid the excessive silicon from being oxidized to form silicon dioxide in the blowing process, and the high-silicic acid slag caused by the silicon dioxide can seriously erode the magnesium furnace lining, so that the refining can be more sufficient; meanwhile, most of sulfur in the blown molten iron (liquid alloy) enters the alloy, so that the sulfur content of the medium-low carbon ferrochrome in the final product is realized at a lower level by reasonably setting the sulfur content, and the quality of the final product is ensured.
The gas mixing device is arranged, so that the components of the gas flow entering the converter molten pool are uniform, the phenomenon of temperature rise while temperature reduction is avoided, meanwhile, the gas flow regulating valve is arranged, so that the proportion of carbon dioxide and oxygen at oxygen lances at different positions is set to be different, and the technical effect of improving the quality of the final product by the aid of different gas source proportions at different positions is greatly enhanced.
If CO is present in the mixed gas2If the proportion is too large, the temperature of the molten pool is greatly reduced, which is not beneficial to decarburization of the melt; if CO is in the mixed gas2If the proportion is too small, the temperature of the molten pool cannot be controlled, and manganese returnsThe yield will be greatly reduced. Meanwhile, the mixed gas with different proportions is simultaneously sprayed at the bottom and the side of the converter, so that the stirring effect on a molten pool is enhanced, and the production of the medium-low carbon ferromanganese is more efficient. Due to CO2The reaction with C is endothermic, while CO is controlled at different positions2And O2The proportion distribution can realize the fine control of the temperature of the molten pool at different positions, and not only can prolong the service life of the refractory lining, but also can reduce the volatilization loss of manganese by finely controlling the temperature of the molten pool.
In addition, most importantly, the invention reasonably sets the mixing proportion of carbon dioxide and oxygen at different positions, and CO is in the top-blown mixed gas2The ratio of (A) is set higher and the ratio of oxygen is lower because the decarburization reaction generally takes place in an emulsion phase formed by liquid metal-slag-gas phase in the furnace, and top-blowing can break down the metal and slag into fine droplets to form an emulsion phase. The invention reasonably sets the proportion of carbon dioxide in top blowing to ensure that CO in top blowing gas2So that CO can be increased2The decarbonization efficiency of (2) and the improvement of CO2The utilization ratio of (c). In addition, the invention generates CO based on the fact that oxygen above a molten pool in the converter is easy to perform secondary combustion with the generated CO2And the principle of heat generation, so the oxygen proportion is set to be lower, thereby effectively controlling the secondary combustion heat release, controlling the furnace temperature, avoiding the serious loss of manganese, and simultaneously avoiding the damage of a jet element and the like due to heating. The invention reasonably sets the proportion of each gas in the bottom blowing mixed gas and sets the CO in the bottom blowing mixed gas2The ratio of (A) is low and the ratio of oxygen is high. Because the stirring intensity of the bottom blowing gas to the molten pool is higher, the oxygen can participate in the metallurgical chemical reaction more effectively, and the oxidation reaction of the oxygen and the impurity elements in the furnace is facilitated. Furthermore, oxygen is more oxidizing than CO2And the oxygen proportion is improved, so that the smelting of ultra-low carbon products is facilitated. Therefore, the invention sets the proportions of carbon dioxide and oxygen in different proportions at different parts for carrying out the blowing at different parts of the converter, can not only reasonably control the furnace temperature and avoid the loss of manganese, but also effectively improve the carbon reduction effect.
Detailed Description
Further description is made with reference to the examples:
example 1:
in a certain steel mill in Hebei, (1) blast furnace smelting is carried out: the raw materials are coke, manganese ore and flux, wherein the coke: manganese ore: the flux (lime is used in the embodiment) is 14.8%:77.3%:7.9 percent of the raw materials are added into a blast furnace according to the sequence of coke, manganese ore and flux, and the air temperature of the blast furnace is set to be 1100 ℃; the tapping interval is 90min, and tapping is performed periodically according to the tapping interval. Wherein the manganese ore comprises the following chemical components in percentage by mass: mn:44.5 wt.% (calculated as manganese equivalent), siO2：19.0wt％，Al2O3:6.4wt%, fe:12.6wt%, and the balance unavoidable impurities. The lime comprises the following chemical components in percentage by mass: caO:85wt% SiO2:5.3wt%, P:0.04wt%, S:0.5wt%, and the balance unavoidable impurities.
The molten product obtained by blast furnace tapping operation is liquid high-carbon ferromanganese, and comprises the following components in percentage by weight: mn:68.0wt%, si:1.3wt%, C:6.2wt%, P:0.12wt%, S:0.011wt%, and the balance iron and inevitable impurities.
(2) Preparing converter raw materials: the liquid high-carbon ferromanganese obtained according to the step (1): cooling agent: 65.3% of silicon-manganese alloy: 21.8%:12.9 percent of the raw materials are mixed; the silicon-manganese alloy comprises the following main components: 15.6wt% of Si, 60wt% of Mn, C:2.0wt%, P:0.2wt%, S:0.04wt%, the balance being unavoidable impurities, the coolant being limestone.
(3) Smelting in a converter: weighing the liquid high-carbon ferromanganese obtained in the step (1), adding into a converter, wherein the adding temperature is 1250 ℃, the converter adopts a top-bottom composite blowing mode, and the top and the bottom of the converter are both blown with a mixed gas of carbon dioxide and oxygen, wherein the volume ratio of the carbon dioxide to the oxygen in the bottom blowing mixed gas is 15%:85%, and the volume ratio of carbon dioxide to oxygen in the top-blown mixed gas is 25%:75%, when the furnace temperature is increased to 1650 ℃, adding the coolant prepared in the step (2), wherein the blowing time of the converter is 65min.
(4) Discharging in a converter: after the converter blowing time is up, adding the silicon-manganese alloy prepared in the step (2) into the converter, and injecting the smelted liquid alloy into a ladle to obtain liquid medium-low carbon ferromanganese; the medium-low carbon ferromanganese comprises the following components in percentage by weight: mn:68.0wt%, si:1.2wt%, C:1.3wt%, P:0.11wt%, S:0.008wt%, the balance being iron and unavoidable impurities.
(5) And (3) granulating: the liquid medium-low carbon ferromanganese obtained in the step (4) is used as a raw material, and a medium-low carbon ferromanganese finished product is produced by adopting the existing molten iron granulation method, and specifically comprises the following steps: hoisting the steel ladle filled with the molten medium-low carbon ferromanganese to a granulation area, and pouring the liquid medium-low carbon ferromanganese into a tundish through a tipping device; the liquid medium-low carbon ferromanganese is impacted to the head of a granulating device below through a water gap at the lower part of the tundish, and medium-low carbon ferromanganese liquid is splashed to finally form liquid granules; cooling the medium-low carbon ferromanganese particles in a granulation tank, and then dropping the cooled medium-low carbon ferromanganese particles to the bottom of the tank; the cooled medium-low carbon ferromanganese particles are sent into a storage bin after the working procedures of dehydration, drying and the like.
The Mn content in the manganese ore in the step (1) is 44.5wt%, and SiO content in the manganese ore is219.0wt% of Al2O36.4wt% and Mn/Fe is 3.53; the average particle size of the manganese ore is 21mm.
In the step (1), the coke contains 84wt% of fixed carbon, 9wt% of ash, 5wt% of water and 5-11 mm of particle size.
In the silicon-manganese alloy in the step (2), the Si content is 15.6wt%, the Mn content is 60.0wt%, the C content is 2.0wt%, the P content is 0.2wt%, the S content is 0.04wt%, and the particle size is 10-12 mm.
And (4) the distance between the top-blown oxygen lance in the step (3) and the liquid level of the charging material is 380mm.
In the embodiment, a gas mixing device is arranged among a carbon dioxide gas source, an oxygen gas source and a blowing oxygen lance, a gas flow regulating valve is arranged among the carbon dioxide gas source, the oxygen gas source and the gas mixing device, and a gas flow regulating valve is also arranged between the gas mixing device and the blowing oxygen lance.
Example 2:
in a certain steel mill in Hebei, (1) blast furnace smelting is carried out: the raw materials are coke, manganese ore and flux, wherein the coke: manganese ore: flux (lime is selected for this example)And fluorite) 14.3 parts by weight: 77.8 parts by weight: 7.6 parts by weight of lime and 0.6 part by weight of fluorite in the flux. Adding the coke, the manganese ore and the flux into a blast furnace in sequence, and setting the air temperature of the blast furnace to be 1100 ℃; the tapping interval is 90min, and tapping is performed periodically according to the tapping interval. Wherein the manganese ore comprises the following chemical components in percentage by mass: mn:37.0 wt.% (calculated as manganese equivalent), siO2：9.0wt％，Al2O3:6.8wt%, fe:10.0wt%, the balance being unavoidable impurities. The fluorite comprises the following chemical components in percentage by mass: caF2：75.6wt％，Al2O3：0.58wt％，CaO：0.49wt％，SiO2:：23.3wt％。
The molten product obtained by blast furnace tapping operation is liquid high-carbon ferromanganese, which comprises the following components in percentage by weight: mn:65wt%, si:1.8wt%, C:7.0wt%, P:0.2wt%, S:0.03wt%, the balance being iron and unavoidable impurities.
(2) Preparing converter raw materials: the liquid high-carbon ferromanganese obtained according to the step (1): cooling agent: 65.8% of silicon-manganese alloy: 21.0%:13.3 percent of the raw materials are mixed; the silicon-manganese alloy comprises the following main components: 16.4wt% of Si, 60wt% of Mn, C:1.8wt%, P:0.2wt%, S:0.02wt%, the balance being inevitable impurities, and the coolant being limestone.
(3) Smelting in a converter: weighing the liquid high-carbon ferromanganese obtained in the step (1), adding into a converter, wherein the adding temperature is 1350 ℃, the converter adopts a top-bottom composite blowing mode, and the top and the bottom of the converter are both blown with a mixed gas of carbon dioxide and oxygen, wherein the volume ratio of the carbon dioxide to the oxygen in the bottom-blown mixed gas is 10%:90 percent, and the volume ratio of carbon dioxide to oxygen in the top-blown mixed gas is 25 percent: and (3) adding the coolant prepared in the step (2) when the furnace temperature is increased to 1700 ℃, wherein the blowing time of the converter is 40min.
(4) Discharging by a converter: after the converter blowing time is up, adding the silicon-manganese alloy prepared in the step (2) into the converter, and injecting the smelted liquid alloy into a ladle to obtain liquid medium-low carbon ferromanganese; the medium-low carbon ferromanganese comprises the following components in percentage by weight: mn:78.5wt%, si:2.0wt%, C:1.3wt%, P:0.30wt%, S:0.02wt%, the balance being iron and unavoidable impurities.
(5) Casting: the liquid medium-low carbon ferromanganese obtained in the step (4) is used as a raw material, and a die casting method is adopted to produce a medium-low carbon ferromanganese finished product, which specifically comprises the following steps: hoisting the steel ladle filled with the liquid medium-low carbon ferromanganese to a casting table, and pouring the liquid medium-low carbon ferromanganese into a tundish through a tipping device; the liquid medium-low carbon ferromanganese flows into the drainage device through a water outlet below the tundish; and the liquid medium-low carbon ferromanganese is dispersedly injected into the mould through the multi-flow holes of the flow diverter, the mould continuously and circularly rotates, and the solidified medium-low carbon ferromanganese product continuously falls off and is then sent into a storage bin.
Example 3:
in a certain steel mill in Hebei, (1) blast furnace smelting is carried out: the raw materials are coke, manganese ore and flux, wherein the coke: manganese ore: the flux (lime is used in the embodiment) is 15.2%:78%:7.8 percent. Adding the coke, the manganese ore and the flux into a blast furnace in sequence, and setting the air temperature of the blast furnace to be 1100 ℃; the tapping interval is 90min, and tapping is performed periodically according to the tapping interval. Wherein the manganese ore comprises the following chemical components in percentage by mass: mn:35.0 wt.% (calculated as manganese equivalent), siO2：12.3wt％，Al2O3:6.0wt%, fe:9.8wt%, and the balance unavoidable impurities.
The molten product obtained by blast furnace tapping operation is liquid high-carbon ferromanganese, and comprises the following components in percentage by weight: mn:62.8wt%, si:1.5wt%, C:7.5wt%, P:0.2wt%, S:0.02wt%, the balance being iron and unavoidable impurities.
(2) Preparing converter raw materials: the liquid high-carbon ferromanganese obtained according to the step (1): cooling agent: 65.7% of silicon-manganese alloy: 20.8%:13.5 percent of the raw materials are mixed; the silicon-manganese alloy comprises the following main components: 15.0wt% of Si, 62.0wt% of Mn, C:2.0wt%, P:0.18wt%, S:0.04wt%, the balance being unavoidable impurities, the coolant being limestone.
(3) Smelting in a converter: weighing and adding the liquid high-carbon ferromanganese obtained in the step (1) into a converter, wherein the adding temperature is 1350 ℃, the converter adopts a top-bottom blowing mode, and the top and the bottom of the converter are both blown with a mixed gas of carbon dioxide and oxygen, wherein the volume ratio of the carbon dioxide to the oxygen in the bottom-blown mixed gas is 10%:90 percent, and the volume ratio of carbon dioxide to oxygen in the top-blown mixed gas is 25 percent: 75%, when the furnace temperature is increased to 1650 ℃, adding the coolant prepared in the step (2), wherein the blowing time of the converter is 40min.
(4) Discharging by a converter: after the converter blowing time is up, adding the silicon-manganese alloy prepared in the step (2) into the converter, and injecting the smelted liquid alloy into a ladle to obtain liquid medium-low carbon ferromanganese; the medium-low carbon ferromanganese comprises the following components in percentage by weight: mn:76.5wt%, si:2.4wt%, C:2.0wt%, P:0.20wt%, S:0.02wt%, the balance being iron and unavoidable impurities.
(5) Casting: the liquid medium-low carbon ferromanganese obtained in the step (4) is used as a raw material, and a die casting method is adopted to produce a medium-low carbon ferromanganese finished product, which specifically comprises the following steps: hoisting the steel ladle filled with the liquid medium-low carbon ferromanganese to a casting table, and pouring the liquid medium-low carbon ferromanganese into a tundish through a tipping device; the liquid medium-low carbon ferromanganese flows into the drainage device through a water outlet below the tundish; and the liquid medium-low carbon ferromanganese is dispersedly injected into the mould through the multi-flow holes of the flow diverter, the mould continuously and circularly rotates, and the solidified medium-low carbon ferromanganese product continuously falls off and is then sent into a storage bin.
Claims (8)
1. A method for smelting medium-low carbon ferromanganese, which is characterized by comprising the following steps:
(1) Blast furnace smelting: the raw materials comprise coke, manganese ore and flux, and the mass ratio of the raw materials is as follows: 76 to 78 parts by weight of manganese ore, 14 to 16 parts by weight of coke and 8978 parts by weight of flux 8978 zxft, and adding the materials into a blast furnace in the order of coke-manganese ore-flux, wherein the blast furnace air temperature is set to be 1000 to 1100 ℃; the tapping period is 90min to 120min, and tapping is carried out periodically according to the tapping period;
the molten product obtained by the tapping operation of the blast furnace is liquid high-carbon ferromanganese, and the components by weight percentage are as follows: mn:60.0 to 82.0wt%, si:1.0 to 2.0wt%, C:2.0 to 8.0wt%, P: less than or equal to 0.30wt%, S: less than or equal to 0.03wt%, and the balance of iron and inevitable impurities;
(2) Preparing converter raw materials: adopting a cooling agent, a silicon-manganese alloy and the liquid high-carbon ferromanganese obtained in the step (1) as raw materials for smelting the converter for proportioning, wherein the proportion is as follows: cooling agent: the silicon-manganese alloy is (64 to 66): (20 to 22): (12-14) preparing materials;
(3) Smelting in a converter: weighing the liquid high-carbon ferromanganese obtained in the step (1) according to the proportion set in the step (2), adding the liquid high-carbon ferromanganese into a converter, wherein the adding temperature is 1250-1350 ℃, the converter adopts a top-bottom composite blowing mode, and the top and the bottom are both blown with mixed gas of carbon dioxide and oxygen, wherein the volume ratio of the carbon dioxide to the oxygen in the bottom blown mixed gas is (5-15): 85-95; the volume ratio of carbon dioxide to oxygen in the top-blown mixed gas is (5 to 35) (65 to 95), when the furnace temperature is increased to 1650 to 1850 ℃, the coolant prepared in the step (2) is added, and the converter blowing time is 32 to 92min;
(4) Discharging by a converter: after the converter blowing time is up, adding the silicon-manganese alloy prepared in the step (2) into the converter, and after the liquid alloy melt in the converter is uniform and stable, discharging the smelted liquid alloy from the converter and injecting the smelted liquid alloy into a ladle to obtain liquid medium-low carbon ferromanganese; the medium-low carbon ferromanganese comprises the following components in percentage by weight: mn:60.0 to 85.0wt%, si: less than or equal to 2.5wt%, C:1.0 to 2.9wt%, P: less than or equal to 0.40wt%, S: less than or equal to 0.03wt%, and the balance of iron and inevitable impurities;
(5) Granulating or casting: adopting the liquid medium-low carbon ferromanganese obtained in the step (4) as a raw material, and producing a medium-low carbon ferromanganese finished product by adopting a molten iron granulation method; or (5) adopting the liquid medium-low carbon ferromanganese obtained in the step (4) as a raw material, and producing a medium-low carbon ferromanganese finished product by adopting a die casting method;
the flux in the step (1) is lime or a mixture of the lime and fluorite; caO in the lime is more than or equal to 80wt%, and SiO in the lime2Less than 6wt%, P less than 0.05wt%, S less than 0.80wt%, and granularity of 10-60mm; caF in fluorite2≥75wt%，Al2O3Less than 0.4 to 0.6 percent, caO 0.49 to 0.53 percent, siO2＜26wt%；
In the step (2), the coolant is one or more of lime, limestone and manganese dust obtained in the smelting process of dried manganese ore or manganese-iron alloy;
in the step (1), mn content in the manganese ore is more than 30wt%, and SiO content in the manganese ore is more than 30wt%2＜20wt%，Al2O3Less than 7wt%, and Mn/Fe is more than or equal to 3; the particle size of the manganese ore is 10-40mm.
2. The method for smelting medium-low carbon ferromanganese as claimed in claim 1, wherein the content of fixed carbon in the coke in step (1) is more than or equal to 84wt%, the ash content is less than 14wt%, the water content is less than 6wt%, and the particle size is 3-20mm.
3. The method for smelting medium-low carbon ferromanganese as claimed in claim 1, wherein the coolant in step (2) is lime, caO in the lime is more than or equal to 85wt%, P is less than or equal to 0.02wt%, and the granularity is 10-50mm.
4. The method for smelting medium-low carbon ferromanganese as claimed in claim 3, wherein in the components of the silicomanganese alloy in step (2), si is 14 to 17wt%, mn is 60 to 70wt%, C is less than or equal to 2.5wt%, P is less than or equal to 0.3wt%, S is less than or equal to 0.05wt%, and particle size is 5 to 15mm.
5. The method for smelting medium-low carbon ferromanganese as claimed in claim 1, wherein in the step (3), the converter further comprises side blowing, and the side blowing is also a mixed gas of carbon dioxide and oxygen, wherein the volume ratio of the carbon dioxide and the oxygen in the side blowing is (5-15): (85 to 95).
6. The method for smelting medium-low carbon ferromanganese as claimed in claim 1, wherein the distance from the top-blown oxygen lance to the liquid level of the furnace burden in step (3) is 350 to 400mm.
7. The method for smelting medium-low carbon ferromanganese as claimed in claim 1, wherein a gas mixing device is provided between the carbon dioxide gas source, the oxygen gas source and the blowing lance, and a gas flow regulating valve is provided between the carbon dioxide gas source, the oxygen gas source and the gas mixing device, and a gas flow regulating valve is also provided between the gas mixing device and the blowing lance.
8. The method for smelting medium-low carbon ferromanganese according to claim 1, wherein the molten iron granulation method in the step (5) is specifically:
the first step is as follows: hoisting the steel ladle filled with the molten medium-low carbon ferromanganese to a granulation area, and pouring the liquid medium-low carbon ferromanganese into a tundish through a tipping device;
the second step is that: the liquid medium-low carbon ferromanganese is impacted to the head of a granulating device below through a water gap at the lower part of the tundish, and medium-low carbon ferromanganese liquid is splashed to finally form liquid particles;
the third step: cooling the medium-low carbon ferromanganese particles in a granulation tank, and then dropping the cooled medium-low carbon ferromanganese particles to the bottom of the tank;
the fourth step: the cooled medium-low carbon ferromanganese particles are dehydrated and dried and then are sent into a storage bin to form a medium-low carbon ferromanganese product;
the die casting method in the step (5) comprises the following specific steps:
the first step is as follows: hoisting the steel ladle filled with the liquid medium-low carbon ferromanganese to a casting table, and pouring the liquid medium-low carbon ferromanganese into a tundish through a tipping device;
the second step is that: the liquid medium-low carbon ferromanganese flows into the drainage device through a water outlet below the tundish;
the third step: and dispersing and injecting the liquid medium-low carbon ferromanganese into the mold through the multi-flow holes of the flow diverter, continuously and circularly rotating the mold, continuously dropping the solidified medium-low carbon ferromanganese product, and then feeding the medium-low carbon ferromanganese product into a storage bin to form the medium-low carbon ferromanganese product.
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| JPH0621318B2 (en) * | 1988-12-21 | 1994-03-23 | 川崎製鉄株式会社 | Melting method of medium / low carbon ferromanganese |
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