CN113699371B

CN113699371B - Preparation and use methods of composite deoxidation modified pellets

Info

Publication number: CN113699371B
Application number: CN202110815352.2A
Authority: CN
Inventors: 陈亚团; 梁金鹏; 任文卓; 李金钢; 常全举
Original assignee: Gansu Jiu Steel Group Hongxing Iron and Steel Co Ltd
Current assignee: Gansu Jiu Steel Group Hongxing Iron and Steel Co Ltd
Priority date: 2021-07-19
Filing date: 2021-07-19
Publication date: 2022-10-25
Anticipated expiration: 2041-07-19
Also published as: CN113699371A

Abstract

The invention discloses a preparation and use method of a composite deoxidation modified pellet, wherein the pellet A comprises the following steps: the balling component is 30-40 parts of dolomite powder according to the mass part ratio: 20-30 parts of steel slag powder: 20-30 parts of process coke breeze: 1.5-2 parts of X-type organic binder: 15-20 parts of Y-type inorganic binder: 3 parts of water, and is produced by adopting a cold ball pressing process; b, pelletizing: the balling component is 30-40 parts of dolomite powder according to the mass part ratio: 20-30 parts of limestone powder: 20-30 parts of process coke breeze: 1.5-2 parts of X-type organic binder: 15-20 parts of Y-type inorganic binder: 3 parts of water, and is produced by adopting a cold-pressing ball process. The pellet A and the pellet B are respectively in two process links of a converter and a refining furnace.

Description

Preparation and use methods of composite deoxidation modified pellets

Technical Field

The invention belongs to the technical field of metallurgy, and particularly relates to a preparation method and a use method of a composite deoxidation modified pellet.

Background

The converter process of part of enterprises has the following problems: the contents of iron oxide and manganese oxide in the slag at the smelting end point of the converter are higher, so that not only is the waste of iron and manganese metals larger, but also the subsequent slag splashing furnace protection effect is influenced due to the higher contents of low-melting-point oxides such as iron oxide, manganese oxide and the like, and meanwhile, the dissolved oxygen in the molten steel is kept in a balanced manner due to the excessive iron and manganese oxides in the slag, so that more dissolved oxygen is kept, and therefore, when the alloy is added into the slag during tapping, the alloy burning loss is large, and the yield is low. In addition, the converter lining also has a reduced life due to the high oxidizability of the slag (i.e., the slag contains high amounts of unstable oxides such as iron oxide, manganese oxide, etc.). The converter procedure generally adopts a mode of improving the carbon content of the molten steel at the end point by adopting scientific burdening to ensure the heat of the converter and improving the operation level of personnel or a mode of adding high-price magnesia and carbon type slag modifier after tapping to solve the problem. In the above manner, the former is restricted by various conditions or requires a long process, and the problem cannot be completely solved; the latter has higher material cost, occupies time for slag adjustment, consumes nitrogen gas for temperature reduction and viscosity increase so as to be splashed and hung, influences the smelting rhythm, does not substantially reduce the oxidizability of slag and recover metals, is not an ideal mode, and needs to be improved. The converter is charged through a storage bin, only blocky materials can be used, and the reason for the large-scale stockpiling of calcium and magnesium powder is also reason. The dolomite dust and the living resources are needed to be utilized by adopting feasible measures with low cost, and the expense burden of enterprises is reduced.

The refining process of part of enterprises has the following problems: taking LF refining process as an example, auxiliary materials are required to be added for slagging, and the effects of reducing oxidation, submerged arc, arc stabilization, S removal and the like of molten steel heat preservation are exerted. The effect can be enhanced by increasing the addition amount of the auxiliary materials, but the cost is higher. In addition, for the ordinary carbon steel heat, when the S removal task is not heavy, the refining station generally adopts low alkalinity and ash slag operation (the FeO + MnO content in the slag is still high when the slag is out of the station), the requirement on the fluidity of the slag is not strict, the lower the S content of the molten steel entering the station is, the lower the alkalinity of the top slag is controlled when the slag is out of the station, and the higher the FeO + MnO content of the top slag of the steel ladle is controlled when the slag is out of the station (the blacker the slag color is). Although the operation seems to save lime, the content of metal oxides such as manganese, iron and the like in the slag is high, which is not beneficial to reducing the alloy consumption, and in addition, the oxidation erosion amount of the electrode is larger due to the higher content of Mn and Fe in the slag. For molten steel de-S, high temperature, low slag oxidability and molten steel oxidability are required. Therefore, an efficient refining mode with low auxiliary material consumption is needed to be adopted, and refining targets such as temperature rise and desulfurization are achieved by creating heat preservation and low-oxidation conditions.

The problem of overstock of dolomite powder: the dolomite powder is a screening product (the granularity is too fine and does not meet the requirement of a calcining process) of natural dolomite lump materials before entering a kiln, the granularity is 0 mm-5 mm, the dolomite powder mainly comprises calcium carbonate and magnesium carbonate, and the main components (expressed by oxides): 30% of CaO, 20% of MgO, 25% of SiO, and the balance of other oxide impurities and undecomposed CO2. The powder has large production amount, wind blowing and dust raising, and large environment protection pressure for open-air stockpiling; the occupied site causes the insufficient stacking site of the newly generated powder, and the production and operation of flux processing units are influenced; the powder is not easy to be fed and mixed in a user unit, dust and shed materials are easy to fly in the using process, and the using difficulty is high; the material value is low, and the material is not suitable for long-distance transportation and can only be consumed nearby. The materials are potential resources, and are not utilized in time, so that the resources are idle, the capital is occupied, and the environmental protection pressure is generated.

The problem of the overstock of the process coke breeze is as follows: the technical coke breeze is carbon dust generated in the coke dry quenching process of a coke plant, the carbon material accounts for 70 percent of 200 meshes, the fixed carbon is slightly lower than the coke, and the main components are as follows: 78-80% of C, 4% of Al2O3, 27% of SiO, 2% of CaO, 0.050% of P, 1.10% of S, and the balance of metal oxides such as iron, potassium, sodium and the like. Sintering ingredients can absorb part of process coke breeze, but because the granularity is too fine and the ingredients are not easy to be prepared and the index is deteriorated, the sintering is only added in small amount in stages, and the using amount is limited. In addition, the fine powder characteristic of the process coke breeze is used by being blown together with blast furnace blowing coal, but the process coke breeze is sticky and wet, is easy to freeze and is difficult to discharge in winter, so that the process coke breeze is not used in large quantity, and is stopped for the coldest three months every year to ensure smooth production. As the carbon is used in the factory in a place mostly using lump coke and lump coal, the process coke breeze is not used completely for iron and steel enterprises, and the cost of the whole process is high.

The problem of steel slag is that: the steel slag can be fully consumed for the eastern province, more enterprises, more population, economic activity, large building material market capacity and the like. But for western provinces with less population, the steel slag users are limited, most of the steel slag is stockpiled except a small amount of the steel slag is used as baking-free bricks, cement and commercial concrete, and if the steel slag can be recycled in a metallurgical process, the recycling of resources can be promoted.

Therefore, it is necessary to develop a method for improving the quality of the converter final slag and the refining effect at low cost by using metallurgical powder, and realizing synergistic cost reduction and efficiency improvement. The method can fully fit the material characteristics with the metallurgical process characteristics, efficiently utilizes the difficult-to-use materials such as dolomite powder, limestone powder, process coke breeze and steel slag, reduces the environmental protection burden of enterprises and improves the benefit.

The invention combines the characteristics of the modern steelmaking process and the characteristics of materials such as dolomite, process coke breeze and the like, develops a systematic process for realizing the modification of the final slag of the furnace by utilizing the metallurgical powdery solid waste at low cost, improving the refining effect and synergistically reducing the cost and improving the efficiency for the first time in China, is a brand new mode for utilizing the powdery solid waste with low investment and high benefit for iron and steel enterprises, and solves the problem to be solved urgently for the iron and steel enterprises.

Disclosure of Invention

The invention provides a preparation method and a use method of a composite deoxidation modified pellet, and aims to provide a preparation method and a use method of a composite deoxidation modified pellet

Therefore, the invention adopts the following technical scheme:

a preparation and use method of composite deoxidation modified pellets comprises the following steps:

1) Preparing pellets:

pellet A: the raw materials are dolomite powder, steel slag powder, technical coke breeze, X-type organic binder and Y-type inorganic binder, and the balling components are 30-40 parts of dolomite powder according to the mass part ratio: 20-30 parts of steel slag powder: 20-30 parts of process coke breeze: 1.5-2 parts of X-type organic binder: 15-20 parts of Y-type inorganic binder: 3 parts of water, and is produced by adopting a cold ball pressing process; the pellet A has the following functions: reducing iron oxide and manganese oxide in the final slag, reducing the oxidability of the slag, changing the phase, improving the melting temperature, and cooperatively reducing the temperature to improve the viscosity of the slag, reducing the slag amount at a steel tapping hole and laying a foundation for prolonging the service life of refractory materials of a slag splashing furnace protection and lining. In addition, the oxygen content of the molten steel is reduced, and conditions are created for improving the yield of the ferroalloy, reducing the alloy consumption and improving the steel quality.

B, pelletizing: the raw materials are dolomite powder, limestone powder, technical coke breeze, X-type organic binder and Y-type inorganic binder, and the balling components are 30-40 parts of dolomite powder by mass: 20-30 parts of limestone powder: 20-30 parts of process coke breeze: 1.5-2 parts of X-type organic binder: 15-20 parts of Y-type inorganic binder: 3 parts of water, and is produced by adopting a cold ball pressing process; the pellet B has the following functions: reducing iron oxide and manganese oxide in the slag, recovering metals, reducing alloy consumption, promoting slag foaming heat preservation and submerged arc stabilization, improving heating efficiency, strengthening reducing atmosphere, and reducing power and graphite electrode consumption.

The functions of the materials are as follows:

dolomite powder: dolomite from flux plants is difficult to be used because of the difficulty in directly feeding the dolomite into a converter in a screening process before entering a kiln, and is often stacked or buried (only applicable to magnesium smelting enterprises), and is used as a content regulator (chemical viscosity increasing when the converter is used), a coolant (endothermic decomposition reaction and physical viscosity increasing when the converter is used) and a ball pressing balance weight (ball density is improved so as to be sunk into the slag and improve the carbon utilization rate) in slag.

Steel slag powder: the steel slag tailings from the metallurgical slag field of enterprises after iron selection can be 0-5 mm undersize powder or steel slag micropowder, belongs to a high-alkalinity material with alkalinity near 3, and has no side effect when being added into a converter. For northwest areas without sand, the steel slag tailings are few in users and difficult to utilize due to numerous substitutes. The steel slag powder is used as the cooling agent of the steel slag in the furnace and the balance weight of the pellet, and the special performance of the steel slag powder is more convenient for the pelletizing and the strength improvement of the pellet.

Limestone powder: the particle size is 0-5 mm, and the particle size is difficult to be directly added into a converter, and the particle size is taken as a CaO content regulator, a coolant (the decomposition reaction absorbs heat and plays a physical lifting role when the converter is used) and a ball pressing and balancing weight (the ball density is improved so as to be deposited in slag and improve the carbon utilization rate) in the functional pellets.

The process comprises the following steps: the material is from the coke dry quenching process of a coke plant, also called dry quenching dust removal ash, the granularity of which is below 100 meshes accounts for 60 percent, although the material is applied in the sintering or blast furnace coal injection process, a series of problems of poor air permeability, bin wall adhesion and the like exist due to the characteristics of fine powder, and the material is remained every year. The functional pellets are used as a reducing agent (deoxidizer) and a foaming agent, the contents of iron oxide and manganese oxide in the slag are reduced through reduction reaction, and the slag is chemically tackified when the converter is used.

X-type organic binder and Y-type inorganic binder: the two materials are easy to obtain and are matched to reduce the cost under the condition of ensuring the strength of the pellets.

Water: a medium which can make the base material and the binder fully contact with each other, and an accelerant which can make the organic binder and the inorganic binder play a binding role.

The detailed steps of pellet preparation are as follows:

(1) Preparing materials: after each base material is loaded to a fluffy automobile by a stacking ground loader, the base material is unloaded to a raw material ground bin of a ball pressing production line, is fed to a separately configured horizontal weighing belt by electric vibration at the lower part of each ground bin, and is conveyed and fed to a mixing machine by a gathering belt after weighing a stirring batch. The two binders were placed in a small storage bin on one side of the gathering belt, weighed by an electric vibration feed into a weighing hopper below, then transported to the gathering belt with a short belt and subsequently fed to a mixer.

(2) Material mixing: an edge runner mixer is adopted, and the rotation of a press roll is not less than 50 circles so as to ensure that the base material, the water and the binder are fully mixed and wetted. Because the technical coke breeze carries water, the water content is detected before the material preparation, and the water is added in the stirring process according to the water content and the technical coke breeze proportion, so that the material is ensured to be fully wetted.

(3) And (3) standing and smothering the mixture: the mixed materials are discharged to a belt conveyor and conveyed to a large taper silo (a stuffy silo). The method is characterized in that a plurality of mixed materials and bins for stirring batches are prepared, the volume of each bin needs to ensure that the materials in each batch can be awake and stuffy for more than 120 minutes, so that the materials are further moistened, and conditions are created for improving the strength of the balls.

(4) And (3) pellet pressing: the mixture after being awakened and stuffy is fed to a conveying belt by electric vibration at the lower part of the conveying belt and then is fed to a double-roller ball press. The balls are put into a ball discharging belt through a grate type inclined sieve plate at the bottom of the ball press, and crushed and powdered materials are conveyed to a gathering belt through a material returning belt under the sieve, and the process is repeated.

2) Conveying in the form of balls

In order to reduce the proportion of the powder carried by the pellets and the crushed material, the following special pellet conveying process is adopted:

(1) Balling and conveying: finished balls are conveyed by the 5-6 sections of multi-stage ball-discharging conveying belts in a head-to-tail connection mode, and finally piled into a conical ball pile through the elevation-type ball-discharging conveying belts, and the subsequent balls roll down by taking a cone as a slope to reduce crushing. The upward-type conveyer belt slightly moves to one side along with the ball discharging process, and finally the ball stack is formed by an inner layer of circular ring hill-beam and an outer layer of circular ring hill-beam which are close to each other. Thus, the turnover is reduced as much as possible, and the powder quantity is reduced.

(2) Dry ball supply: the pellets of the ball pile are taken and used according to the principle of first production and first use, are loaded to a vehicle with a cloth screen by a loader and are pulled to a converter auxiliary material ground bin or a refining auxiliary material ground bin of a steelmaking unit, and are dumped after being opened for dust removal. After entering the ground bin, the pellets are fed to an auxiliary material feeding conveying belt through electric vibration at the bottom of the ground bin and conveyed to an auxiliary material distributing platform, and are distributed to a high-level storage bin above the converter or the refining furnace for later use by a distributing trolley. For the refining station, because the adding amount of each furnace is small, the pellets can also be loaded into small bags of 10kg and prepared in a hopper at one side of the refining station.

3) Adding materials:

(1) The mode of adding pellets a in the converter: feeding the pellets in the high bin to a weighing bin by electric vibration, opening a gate valve to enter a collecting bin after weighing, opening the gate valve of the collecting bin, and enabling the pellets to enter the furnace through a chute on a flue; after temperature measurement and sampling, adding pellets when a converter is shaken vertically, wherein the dosage of each ton of steel is 3 kg-6 kg; after the steel is added, the furnace is shaken backwards for 70 degrees, and the controller is switched to the furnace, the speed of the steel is preferably reduced to 50 percent of the usual speed when the controller shakes the furnace to tap steel behind the furnace, so that the slag is prevented from being foamed and largely rushes out of the furnace opening;

the adding mode utilizes the impact effect of high-position falling bodies, the problem that the density of the ball is smaller than the slag density can be solved, the ball is arranged below the slag surface within several seconds of falling, then most of the slag in the volume is soaked in most of the time, and meanwhile, the high-position adding is easier to disperse on most of the slag surface, so that the effects of reducing metal, reducing oxidability and reducing temperature and increasing viscosity of the ball are fully embodied, the slag quantity at a steel tapping hole can be reduced by higher slag viscosity, and a foundation is laid for slag splashing protection subsequently. The adding amount is controlled to be 3-5 kg per ton of steel, so that the temperature of a molten pool can be prevented from being obviously reduced, and the smooth tapping is ensured. The small addition amount, the pause time of the switching of the controller and the slow furnace shaking can ensure the full reaction of the pellets and the slag and reserve the defoaming time, ensure the deoxidation modification effect and simultaneously prevent the foamed slag from flowing out of the furnace mouth in the tapping process.

(2) Adding a pellet B into the refining furnace: feeding the pellets in the high bin to a weighing bin by electric vibration, opening a gate valve after weighing, feeding the pellets into a multi-section conveying belt, and finally adding the pellets into a steel ladle through a bin with a gate at the tail end; the dosage of each ton of steel in the refining station is 1 kg-2 kg, and the steel is added for a few times (more than 3 times) before and in the middle period of refining, 10kg each time; after the ball is added, the dosage of auxiliary materials such as lime and the like is gradually reduced.

Pellet B is added to the refining furnace, because the oxidizability of the incoming station slag is higher, and the pellet B is added a small amount of times through a bunker with certain implementation in the middle and early stages of refining, so that the metallurgical effect can be guaranteed to the greatest extent: the top slag oxidability is weakened and the foaming time is prolonged as far as possible by carrying out metal reduction through the reaction of carbon, iron oxide and manganese oxide, so that the lower oxidability, thicker thickness and better heat-preservation submerged arc stabilizing effect of the slag are ensured in most refining time, conditions are created for reducing the oxygen potential and improving the temperature rising efficiency, the desulfurization is promoted, the metal yield is improved, and the electrode consumption and the power consumption are reduced. Because the sampling is carried out for at least 3 times during the refining period, the pellets have weak recarburization effect, and the pellets are added for a few times in the early and middle periods, thereby being beneficial to finding out the component problem in advance and disposing in time. In addition, a small amount of multiple adding modes are adopted, so that the phenomenon that top slag foaming is too concentrated can be avoided, and a large amount of slag overflowing is avoided.

The invention relates to a multifunctional material action principle

(1) Principle for reducing oxidability of steel slag and molten steel

When the carbon steel is used in a converter or refining, the carbon in the ball reduces iron oxide and manganese oxide in slag at high temperature of the slag, and the reaction is FeO + C = Fe + CO, fe ₂ O ₃ +3C =2Fe +3CO and MnO + C = Mn + CO, both belonging to endothermic reactions; because of the oxygen carrier Fe in the slag _X O _Y The MnO type oxide is balanced with dissolved oxygen in molten steel to reduce Fe in slag _X O _Y And MnO is beneficial to reducing dissolved oxygen in molten steel.

(2) Principle of slag foaming

Carbon oxygen reaction FeO + C = Fe + CO or Fe ₂ O ₃ +3C =2Fe +3CO generates CO gas, and the gas is coated by slag to form bubbles; caCO for carbonate decomposition in limestone or dolomite ₃ =CaO+CO ₂ Or MgCO ₃ =MgO+CO ₂ Production of CO ₂ Gas, which is coated with slag to form bubbles. The slag is foamed and thickened, the heat-resistant effect is improved, the submerged arc is facilitated, the electrode oxidation is reduced, and the heat preservation and oxidation resistance of a metal molten pool are reduced.

(3) Principle of enhancing slag viscosity

The above carbon-oxygen reaction or carbonate decomposition reaction is endothermic reaction, and the slag is enhanced by lowering the temperature of the slagViscosity, which is physical thickening; mgO and CaO contained in the carbonate are high-melting-point phases themselves, which are associated with other components of the slag, such as SiO ₂ And Al ₂ O ₃ Oxides also form high melting phases, which are chemically sticky.

(4) Density enhancing principle by using calcium magnesium carbonate

The compaction density of the coke breeze is only 1000kg/m in the process, and the carbon utilization rate is low when the coke breeze is added independently. The compacted density of 0-5 mm limestone and dolomite is 2000kg/m, and the density of steel tailings is 2500kg/m, and the average density after the materials are matched and pressed for balling can reach about 2000kg/m, and most are submerged by the slag after adding, and in addition, the inertia effect during charging is increased, and the carbon utilization rate is increased.

The invention has the beneficial effects that:

1. the invention adopts dolomite powder, limestone powder, steel slag powder, fly ash and other low-price, difficult-to-treat and easily-available powder to manufacture according to the metallurgical principle in a set proportion, is convenient for preparing pellets, has lower cost, improves the resource utilization rate, survives resources and reduces the enterprise expense burden.

2. The invention adopts a special ball pressing process of the processes of material preparation, material mixing, mixture stuffiness, roller ball pressing and the like, and adopts a ball output mode that 5-6 sections of ball output conveyer belts are connected end to output balls, preformed conical balls are stacked into a buffering slope and a multilayer circular ring mountain beam. The mode is favorable for improving the strength of the ball, reducing the using amount of the binder, reducing the amount of the powder as much as possible and reducing the comprehensive cost.

3. The converter adopts a mode of adding the material bin before tapping, ensures that the pellets and the slag have sufficient reaction time, ensures safety and ensures the modification effect of the steel slag; the refining adopts a mode of adding a small amount of molten steel for multiple times in the early and middle stages, can ensure that the components of the molten steel discharged from the station reach the standard, and avoids slag overflow and material waste caused by centralized use while exerting the functions of promoting foaming and arc burying, reducing power consumption, reducing electrode consumption and reducing metal.

4. The invention utilizes cheap and difficult-to-use materials, with less investment and reliable theoretical support, and easy-to-realize ball pressing processing mode and charging mode, and realizes the metallurgical purposes of steel slag modification, metal recovery, slag viscosity improvement and refractory and alloy saving in the converter; the effects of metal recovery, alloy saving, foaming promotion, temperature rise efficiency improvement, power consumption and electrode consumption saving are realized in the refining furnace. The investment is low on the whole, and the effect is quick.

5. The two pellets designed by the invention are added in two process links of a converter and a refining furnace respectively, the adding mode fully considers the characteristics of materials in the pellets and the process characteristics of each link, and the metallurgical function of the pellets can be exerted to the maximum extent.

Detailed Description

The invention will be further illustrated with reference to specific examples:

1) Preparing pellets:

pellet A: the raw materials are dolomite powder, steel slag powder, technical coke breeze, X-type organic binder and Y-type inorganic binder, and the balling components are 30-40 parts of dolomite powder according to the mass part ratio: 20-30 parts of steel slag powder: 20-30 parts of process coke breeze: 1.5-2 parts of X-type organic binder: 15-20 parts of Y-type inorganic binder: 3 parts of water, and is produced by adopting a cold ball pressing process;

b, pelletizing: the raw materials are dolomite powder, limestone powder, technical coke breeze, X-type organic binder and Y-type inorganic binder, and the balling components are 30-40 parts of dolomite powder according to the mass part ratio: 20-30 parts of limestone powder: 20-30 parts of process coke breeze: 1.5-2 parts of X-type organic binder: 15-20 parts of Y-type inorganic binder: 3 parts of water, and is produced by adopting a cold ball pressing process;

(1) Preparing materials: each basic material is loaded to a fluffy car by a stacking loader, then is unloaded to a raw material bin of a ball pressing production line, is fed to a separately configured horizontal weighing belt by electric vibration at the lower part of each bin, and is conveyed and fed to a mixer by a gathering belt after weighing a stirring batch. The two binders were placed in a small storage bin on one side of the gathering belt, weighed by an electric vibration feed into a weighing hopper below, then transported to the gathering belt with a short belt and subsequently fed to a mixer.

(2) Material mixing: an edge runner type mixer is adopted, and the rotation of a press roll is not less than 50 circles so as to ensure that the base material, the water and the binder are fully mixed and wetted. As the technical coke breeze carries water, the water content is detected before the material preparation, and the water is added in the stirring process according to the water content and the proportioning of the technical coke breeze, thereby ensuring the material to be fully wetted.

2) Conveying in the form of balls

In order to reduce the proportion of the pellets carrying the powder and the crushed material, the following special pelletizing and conveying process is adopted:

(2) Dry ball supply: the pellets of the ball pile are taken and used according to the principle of first production and first use, are loaded to a vehicle with a cloth screen by a loader and are pulled to a converter auxiliary material ground bin or a refining auxiliary material ground bin of a steelmaking unit, and are dumped after being opened for dust removal. After entering the ground bin, the pellets are fed to an auxiliary material feeding conveying belt through electric vibration at the bottom of the ground bin and conveyed to an auxiliary material distributing platform, and are distributed to a high-level storage bin above the converter or the refining furnace for later use by a distributing trolley. For the refining station, because the amount of pellets fed to each furnace is small, the pellets can also be packed in 10kg sachets, which are stocked in a hopper on the side of the refining station.

3) Adding materials:

It should be noted that the above are only some embodiments of the present invention, and it should be noted that, for those skilled in the art, many modifications and substitutions can be made without departing from the technical principle of the present invention, and these modifications and substitutions should also be regarded as the protection scope of the present invention.

Claims

1. The application method of the composite deoxidation modified pellet is characterized by comprising the following steps:

1) Preparing pellets:

2) Adding materials:

(1) The mode of adding pellets a in the converter: feeding the pellets in the high bin to a weighing bin by electric vibration, opening a gate valve after weighing to enter a collecting bin, opening the gate valve of the collecting bin, and enabling the pellets to enter the furnace through a chute on a flue; after temperature measurement and sampling, adding pellets when a converter is shaken vertically, wherein the dosage of each ton of steel is 3 kg-6 kg; after the steel is added, the furnace is shaken backwards for 70 degrees, and the controller is switched to the furnace, and the speed is slowed down to be 50 percent of the usual speed when the small-room furnace shaking is used for tapping after the furnace, so that slag is prevented from being foamed and largely rushes out of a furnace opening;

(2) Adding a pellet B into the refining furnace: feeding the pellets in the high bin to a weighing bin by electric vibration, opening a gate valve after weighing, feeding the pellets into a multi-section conveying belt, and finally adding the pellets into a steel ladle through a tail bin with a gate; the dosage of each ton of steel in the refining station is 1 kg-2 kg, and 10kg of the steel is added for at least 3 times before and during refining; after the ball is added, the dosage of the lime auxiliary material is reduced.