CN103540708A

CN103540708A - Molten iron gasification silicon-removing nano-grade SiO2 recovery method

Info

Publication number: CN103540708A
Application number: CN201310477512.2A
Authority: CN
Inventors: 李宏; 年武; 冯佳; 宋文臣; 李晨晓
Original assignee: University of Science and Technology Beijing USTB
Current assignee: University of Science and Technology Beijing USTB
Priority date: 2013-10-14
Filing date: 2013-10-14
Publication date: 2014-01-29
Anticipated expiration: 2033-10-14
Also published as: CN103540708B

Abstract

The invention belongs to the field of steel metallurgy, and relates to a method for removing silicon element through gasification through blowing O2 into molten iron. The method is applied in molten iron pretreatment before steelmaking production. The method is characterized in that O2 or O2+CO2 mixed gas is blown into molten iron with low oxygen supply speed, such that silicon in molten iron is removed, and nano-grade SiO2 particles are recovered from the flue gas. Carbon content of the molten iron is 2.5-5.2wt% and silicon content in molten iron is 0.2-5wt%. CO2 concentration in blowing gas is 0-40%. Blowing gas speed is 0.1-30Nm<3>/min per ton of steel. A treatment time is 0.5-30min. The O2 or O2+CO2 mixed gas blowing process is that a molten iron container is placed in a sealed tank with a flue gas recovery device, and blowing is carried out; or a gas hood is directly covered on the molten iron container, and blowing is carried out. The method has the advantages that: on the basis of reducing slagging raw material consumption and heat consumption, nano-grade SiO2 recovery is realized, investment is low, cost is low, and the resource can be comprehensively utilized.

Description

Nanometer SiO is reclaimed in a kind of molten iron gasification desiliconization 2method

Technical field

The invention belongs to ferrous metallurgy field, be applied to the hot metal pretreatment before STEELMAKING PRODUCTION.

Background technology

In the middle of ironmaking-steelmaking process, be generally provided with hot metal pre process procedures, its objective is desiliconization, dephosphorization, desulfurization, be commonly called as " three is de-".Manufacturing enterprise, according to smelting steel grade, starting material condition and running cost, adopts different technique selectively, existing enforcement " three is de-", also there are one, two that carry out wherein, or do not establish this operation, and will be at pretreatment process dephosphorization, must first desiliconization.This is that element oxidation thermodynamics of reactions rule determines.

Present molten iron method for desilication is to force fast oxygen supply to make silicon generate SiO in molten iron ₂float in slag, add some alkaline slag making raw material lime and fusing assistants simultaneously, make SiO ₂react generation Calucium Silicate powder reduction a with the CaO in lime _siO2, to accelerate [Si]+O ₂=SiO ₂reaction, makes the silicon in molten iron accelerate to shift in slag, then removes and containing white residue, obtains hot metal containing low silicon.Therefore, present desilication method will consume slag making raw material, and slag making raw material intensificationization slag is wanted consumption of calorie, and the desiliconization slag of generation needs to process, and inevitably can cause iron, manganese loss containing some iron and manganese in slag, this all consumption all increases with desiliconization amount.

Theoretical investigation is found, is oxidized the silicon in molten iron, both can generate SiO ₂, also can generate gaseous state SiO, the reaction formula that generates SiO is: [Si]+1/2O ₂=SiO.[Si]-O ₂the different condition of resultant of reaction is: generate SiO ₂reaction needed have enough oxygen, under this condition, generate SiO ₂reaction preferential, can not generate gaseous state SiO, the height of temperature there is no impact; But when the oxygen amount of supplying with is inadequate, can not generate SiO ₂if there is higher temperature just can generate gaseous state SiO.Therefore if control speed of oxygen supply, the satisfied SiO that generates ₂needs, just can in higher temperature province, make molten iron in silicon generate gaseous state SiO and remove.Oxygen blast condition Xia Huodian district temperature can reach nearly 3000 ℃, generates gaseous state SiO enough for reaction, if adjust the Fe-O that form of nozzle can also expand high temperature ₂contact surface, therefore can meet [Si]+1/2O ₂=SiO reaction is for the requirement of temperature.If adopt the desilication method of this generation gaseous state SiO, just can reduce above-mentioned various consumption, reach the object of energy-saving and emission-reduction.Fig. 1 has provided under typical hot metal composition [C] 4.2%, [Si] 0.4% condition, and in molten iron, silicon generates the rationale of gaseous state SiO: on iron-aerosphere face

at suitable P _siOand a _siO2in angle, [Si] may be oxidized and generate SiO and the removal of volatilizing.

If adopt above-mentioned gasification desiliconization of hot metal method, SiO generates volatilization and leaves after molten iron face, can react with the oxygen in gas phase and generate solid SiO ₂, its granularity is nano level.Nanometer SiO ₂it is important hitech materials, be commonly called as " ultra-fine white carbon black ", surface adsorption power is strong, dispersing property is good, the aspect such as thermal resistance, resistance has special performance, can be used as additive, support of the catalyst, discoloring agent, matting agent, rubber reinforcing filler, plastics filling agent, ink thickening material, the soft polishing agent of metal, insulation and thermal insulation weighting agent, high-grade daily-use makeup filler and spray material, be widely used in every profession and trade.Therefore should be reclaimed.

Summary of the invention

The present invention seeks to solve present desilication method and will consume slag making raw material, slag making raw material intensificationization slag is wanted consumption of calorie, and the desiliconization slag of generation needs problem to be processed.Realize nanometer SiO simultaneously ₂recovery.

According to calculating, can draw the balance on the high-carbon iron water surface

be about 10 ³left and right, suitably controls oxygen flow and pressure and can keep

in this level.Control slag ingredient and can keep a _siO2between 1～0.1.P is pressed in the generation of SiO _siO=10 ^-4below just there is volatilization effect, P while improving temperature _siOcan be higher, at oxygen, contact in Huo Dian district and can access higher temperature with molten iron, thereby guarantee that SiO generates volatilization.Laboratory experiment has confirmed this result.

According to above-mentioned theory and experimental studies results, the present invention proposes a kind of to molten iron Small Amount winding-up O ₂in weak oxide atmosphere, generate SiO and remove, reclaim nanometer SiO ₂method, replace existing pressure oxygen supply to make the method that basic slag carries out molten iron pre-desiliconizing, and can access nanometer SiO ₂.

A kind of to the O that jets in molten iron ₂gasification removes the method for element silicon.It is characterized in that to molten iron (carbon content is 2.5%～5.2%, and silicone content is 0.2%～5%) with low oxygen supply speed winding-up O ₂or O ₂+ CO ₂mixed gas, removes the silicon in molten iron and from flue gas, reclaims nano level SiO ₂particle.Molten iron container can be placed in the airtight tank with flue gas recovery device and carry out, also can directly cover on molten iron container and carry out with petticoat pipe, to reclaim nano level SiO ₂particle.

Molten iron container used can use the container of the transportation molten iron such as steel-making converter or iron ladle, torpedo tank car.Blowing method can top blast, bottom blowing or side-blown, or wherein two kinds of methods or three kinds of methods collocation are used, and blowing device used adopts now ripe top-blown spray gun, bottom blowing jet pipe or side-blown spray gun.

Spray gun used and nozzle can be used metal material, also can use non-metallic material.

CO in blowing gas used ₂concentration is 0～40%.Blowing gas speed is at ton steel 0.1Nm ³/ minute to 30Nm ³/ minute between, the treatment time is 0.5-30 minute.

Advantage of the present invention is when reducing slag making raw material consumption and heat exhaustion, realizes nanometer SiO ₂recovery, less investment, cost are low, realize comprehensive utilization of resources.

Accompanying drawing explanation

Fig. 1 is different SiO dividing potential drops, SiO ₂under activity

relation with temperature

Embodiment

Embodiment 1 tests in 1kg crucible, and molten iron carbon content is 4.2%, and silicone content is 0.4%, and temperature rises to 1300 ℃ of power failures.With alundum tube, be inserted into crucible bottom, with 0.1Nm ³/ minute speed winding-up O ₂, after 5 minutes, stopping, thermometric sampling analysis learns, and temperature is 1380 ℃, and the carbon content in molten iron is 4.0%, and silicone content is 0.1%.

Embodiment 2 tests on induction furnace, with the petticoat pipe pipeline of steel pipe manufacturing, inserts in the air collector water of 10 liters, and another outlet connection small vacuum pump of bottle, petticoat pipe covers induction furnace fire door, opens osculum and insert alundum tube on petticoat pipe.In stove, pack 5kg iron into, be warming up to 1305 ℃ of power failures, sampling analysis carbon content is 4.3%, and silicone content is 0.5%, and the alundum tube that is 3mm with internal diameter inserts in molten iron and blows O ₂, injecting velocity is 1 liter/min, blows 10 minutes.Open while blowing and start vacuum pump, furnace gas enters in air collector water along pipeline, and water little by little becomes white casse liquid.After finishing blowing, molten iron temperature is 1373 ℃, analyzes hot metal composition, and carbon content is 4.0%, and silicone content is 0.1%; In air collector water, after solids precipitation, separated being dried carried out chemical analysis and grain-size measurement, learns SiO ₂content is 99.3%, and granularity is less than 100nm and accounts for more than 90%.

Embodiment 3 tests are carried out in 30 tons of converters, and molten iron carbon content is 4.1%, and silicone content is 0.6%, and molten iron temperature is 1317 ℃.Insert oxygen lance spraying and blow O ₂, speed of oxygen supply is ton steel 1Nm ³/ minute, the thermometric sampling 5 minutes time of blowing, molten iron temperature is 1400 ℃, and analyzing molten iron carbon content is 3.7%, and silicone content is 0.25%.

Embodiment 4 tests are carried out in 10 tons of hot metal ladle, and molten iron carbon content is 4.3%, and silicone content is 0.5%, and molten iron temperature is 1427 ℃.Insert oxygen lance spraying and blow 70%O ₂+ 30%CO ₂, air feed speed is ton steel 2.6Nm ³/ minute, the thermometric sampling 4 minutes time of blowing, molten iron temperature is 1430 ℃, and analyzing molten iron carbon content is 3.9%, and silicone content is 0.14%.

Claims

1. one kind to the O that jets in molten iron ₂gasification removes the method for element silicon, it is characterized in that to molten iron with low oxygen supply speed winding-up O ₂or O ₂+ CO ₂mixed gas, removes the silicon in molten iron and from flue gas, reclaims nano level SiO ₂particle; In molten iron, carbon content is 2.5%～5.2wt%, and silicone content is 0.2%～5wt%.; CO in blowing gas used ₂concentration is 0～40%; Blowing gas speed is at ton steel 0.1Nm ³/ minute to 30Nm ³/ minute between, the treatment time is 0.5-30 minute, winding-up O ₂or O ₂+ CO ₂mixed gas process is that molten iron container is placed in the airtight tank with flue gas recovery device and is carried out, or directly covers on molten iron container and carry out with petticoat pipe.

2. a kind of to the O that jets in molten iron according to claim 1 ₂gasification removes the method for element silicon, it is characterized in that, the container of molten iron container use steel-making converter used or iron ladle, torpedo tank car transportation molten iron; Blowing method employing top blast, bottom blowing or side-blown, or wherein two kinds of methods or three kinds of methods collocation uses, blowing device used adopts now top-blown spray gun, bottom blowing jet pipe or the side-blown spray gun of maturation.

3. a kind of to the O that jets in molten iron according to claim 1 ₂gasification removes the method for element silicon, it is characterized in that, spray gun used and nozzle are used metal material or use non-metallic material.