CN102994688A

CN102994688A - Pretreatment technology of terminal steel slag in converter

Info

Publication number: CN102994688A
Application number: CN2011102784293A
Authority: CN
Inventors: 王虎
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-09-16
Filing date: 2011-09-16
Publication date: 2013-03-27
Anticipated expiration: 2031-09-16
Also published as: CN102994688B

Abstract

The invention discloses a pretreatment technology of terminal steel slag in a converter, which mainly comprises the steps of: adding a fluxing agent or the fluxing agent and a reducing agent into the converter from an overhead bunker before the converter blowing terminal to carry out pretreatment on the terminal steel slag. The steel slag is diluted by adding the fluxing agent in the stick steel slag near the terminal; and after adding the fluxing agent and the reducing agent in the diluted steel slag, the content of FeO in the steel slag is decreased by moderate reduction in the premise of keeping the favorable liquidity of the slag. By adopting the technology disclosed by the invention, the content of MFe in the slag can be reduced substantially or the content of FeO in the slag can be reduced moderately, thereby increasing the yield of the molten steel, and providing precondition for increasing the processing ratio in the follow-up process of wind quenching and other granulation processes of the steel slag and deep reduction of FeO in the slag and improving the converter protection effect of slag splashing.

Description

Terminal point pretreatment of slag technique in a kind of converter

Technical field

The present invention relates to the slag processing field, be specifically related to a kind of terminal point pretreatment of slag technique of bessemerizing.

Background technology

For alleviating the terminal point slag to the erosion of furnace lining and being convenient to pushing off the slag and the slag splashing operation, process for making all requires the terminal point slag is glued, by converter dross furnace retaining processing requirement before 1994 with finishing slag " work glues, hangs up ", the splashing slag in converter job requirements of carrying out afterwards by 1994 " is changed the terminal point slag thoroughly to glue ", the terminal point slag is more done more sticking, converter lining life also increases to more than 4000 heats by initial more than 440 stoves, and reaches more than present 30,000 heats, and furnace life, revolutionary variation occured.But the metallic iron of taking away in the slag (MFe) is also increased to more than 10% by former 5-8% because slag viscosity improves.The metal iron loss is unlikely again to affect the slag splashing operation in order to reduce, and developed the ZL01111081.3 patented technology, but the metal in the dreg iron loss on average still reaches 6.6%; In the stove in the tapping process after the reduction of this technology in the slag TFe content still higher, reach 12.5%.For a long time; for reclaiming many Technologies and the devices such as metallic iron (MFe) is developed in the slag fragmentation, magnetic separation; basically technique is numerous and diverse, energy consumption is high, the metallic iron rate of recovery is low, seriously polluted and a large amount of tailings can't utilize or added value is low; and safe and efficient, deslagging is fast, floor space is little, pollution is little, the granulation performance is good, wind that the slag produce added value is high is quenched etc., and the pelletizing technology processing rate only has greatly 30-50% because of slag viscosity, remaining slag still will adopt the art breading such as high pollution, high energy consumption.In order to improve the wind granulating steel slag art breading rate such as quench, developed specially " slag liquefaction heating process and device " (number of patent application 201010559657.3), but this technical costs is high, complex process, not practical application.

Summary of the invention

Order of the present invention provides a kind of terminal point pretreatment of slag technique of bessemerizing, and this technique can further reduce in the finishing slag MFe content or appropriateness reduces (FeO) content in the hyperoxia voltinism finishing slag, further improves the molten steel recovery rate; And for follow-up slag wind quench wait the pelletizing technology processing rate bring up to or near 100% and stay (FeO) in the interior slag of stove drastic reduction, improve the slag splashing effect precondition be provided.

Technical scheme of the present invention is such: during the converter smelting, early stage morningization slag, mid-term the slag suitable viscosity, latter stage, namely bessemerize close on end before, add fusing assistant in the stove by high hopper and will close on the slagization that the terminal point slag glues heat and thoroughly do rare; And to closing on terminal point height (FeO) shoddye heat, in stove, add fusing assistant and reductive agent by high hopper, and guaranteeing under its mobile fully good prerequisite, with the reduction of (FeO) appropriateness, reduce its oxidisability.The traditional idea that the technical program has fundamentally broken through steel-making terminal point slag " work glues, hangs up ", " change and thoroughly glue " closes on blow end point and slag is done rare.And after going out to finish part terminal point slag, again before tapping or in the tapping process, make and stay that (FeO) drastic reduction becomes sticky slag in the interior slag of stove by adding the reductive agents (or imposing stirrings) such as C matter in the slag in stove.

The present invention is based on the thick and rare Different Results that produces of terminal point slag and develops.Starting material reason and the processing requirements thereof such as converter smelting middle, high-carbon kind, low-phosphorous steel grade and molten iron, lime, basicity R is too high, finishing slag (FeO) excessively low (TFe＜12%), all can cause the terminal point slag more sticking; Other low-carbon (LC)s, Ultra-low carbon steel grade, after-blow heat are then high because of (TFe 15-30%) content in the finishing slag, cause the terminal point slag thin, need to add a large amount of MgO materials (MgO) over-saturation could be glued.Both one because slag is sticking MFe content is increased, another reduces because metallic iron oxide compound (FeO) content height all causes the molten steel recovery rate.The terminal point slag is stained with to be beneficial to and alleviates converter lining and corrode, and is conducive to pushing off the slag, is conducive to the slag splashing operation, but has increased the metal iron loss, the pelletizing technology processing rate such as reduced that wind is quenched; On the contrary, the terminal point slag is rare, and MFe content is low in the slag; Good fluidity, the wind pelletizing technology processing rate such as quench is high; (FeO) mass transfer velocity is fast, is conducive to stay slag (FeO) the fast deep reduction in the stove in tapping process, thereby further improves the molten steel recovery rate, reduces reductor, alloy consumption, improves steel quality.There are some researches show that when R, (MgO) content are in the situation of certain certain value, the TFe content of liquid slag is 〉=17.5%, the slag of good fluidity is 〉=15.3%, is≤13.4% than viscous slag.Be that TFe content is higher in the slag, slag viscosity is less, and the slag flowability is better, otherwise then more sticking.Accompanying drawing is French Usinor-Dunkirk factory and Suo Limei-FOX steel mill finishing slag metal iron shot (MFe) content and the full ferric oxide of finishing slag (TFe) relation.As seen from the figure, (TFe) content is higher in the slag, and slag is rarer, and MFe is lower in the slag.Along with finishing slag (TFe) content improves, slag metal iron shot content sharply reduces, but along with after the raising of (TFe) content and reaching certain numerical value (about 15%), slag metal iron shot content only has 1-3%, and tends to be steady.

Embodiment

Make slag keep the reasonable viscosity blowing in the smelting process, to form suitable foamy slag, emulsion acceleration metallurgical reaction to smelting latter stage, before closing on blow end point, in 1-2 minute, to the heat of terminal point than the viscosity slag, in stove, add fusing assistant (≤4kg/ ton steel) by high hopper; To the rarer heat of high (FeO) slag, in stove, add fusing assistant+reductive agent (C matter reductive agent, silicon calcium powder, carborundum powder etc.) by high hopper, the terminal point slag is carried out pre-treatment.Fusing assistant addition≤0-4kg/ ton steel, reductive agent (net content) addition≤1kg/ ton steel, concrete add-on and joining day decide on slag condition, dissolving agent, reductive agent kind.The viscosity slag by such simple process after (but not carry rifle operation), dry slag is thinning; High (FeO) shoddye is keeping under its abundant good fluidity prerequisite, and (FeO) reduced by the appropriateness reduction in the slag, when adopting C matter reductive agent, adds under C amount (carbon≤1.0kg/ ton steel) prerequisite in control, and molten steel does not increase C.MFe falls after rise in the molten steel fast in the slag, and the molten steel recovery rate improves.Behind the blow off, sampling, thermometric, slag tap, enter the slag good fluidity in the slag narrow-necked earthen jar, and remaining MFe sinks at the bottom of the narrow-necked earthen jar in the slag, slag, steel separate.Liquid slag is all through the slag pilletizer fast processing, processing rate 100%, and slag is difficult for dry slag narrow-necked earthen jar, middle narrow-necked earthen jar.Stay the interior liquid slag of stove after slagging tap before tapping or in the tapping process, by drastic reduction, (FeO) content further reduces in the slag by reductive agents (FeO) such as interpolation C matter in slag, and slag becomes sticky.Tapping is finished, and implements the slag splashing operation.

The technology of the present invention exploitation depends on the technical support of Technology of Slag Splashingfor Furnace Maintenance and patent ZL01111081.3, and also being above-mentioned binomial technology provides precondition for exploitation and the enforcement of the technology of the present invention.

The terminal point slag is rare unfavorable to furnace lining and pushing off the slag.But the enforcement of Technology of Slag Splashingfor Furnace Maintenance has made lining erosion speed be tending towards " zero " corrodes, in addition finishing slag is done rare short to the time of slagging tap, behind the converter blow off just machinery-free wash away, to spatter slag blanket identical with the finishing slag composition for furnace lining in addition, chemical erosion is low.Therefore, because the technology of the present invention is made finishing slag rare, shoddye can be eliminated by slag splashing technique fully to the erosion that furnace lining brings.In addition; tap in front or the tapping process, (FeO) drastic reduction becomes sticky slag in the slag; eliminated the rare possibility that the lower quantity of slag is increased of finishing slag fully, and the protection that combined blown converter furnace bottom wind is chewed when not only being conducive to slag splashing and also being conducive to spatter slag of low (FeO) slag.Therefore, the exploitation of the technology of the present invention realizing the object of the invention while, by above-mentioned binomial patented technology, has been eliminated the side effect that this process implementing brings.

The fusing assistant that adds claims again dissolving agent or shoddye agent for steel-making helps the appearance agent, can be natural materials, also can be synthetic material.It is effective wherein to change slag, can strengthen slag, steel interfacial tension person and be one of preferred version.The reductive agent that adds is carbonaceous reducing agent, silicon carbide and the silicon calcium powders such as coke powder, coal, graphite.

The below further specifies the present invention with embodiment, but protection domain of the present invention is not limited.

Embodiment:

Claims

1. bessemerize terminal point pretreatment of slag technique for one kind, it is characterized in that converter closes on before the blow end point by feed bin and add fusing assistant in the stove or add simultaneously reductive agent and fusing assistant carries out pre-treatment to slag.

2. such as right 1 described terminal point pretreatment of slag technique, it is characterized in that before the terminal point blow off, by feed bin to stove in adding fusing assistant in 1-2 minute to closing on the sticking heat of blow end point slag, do the terminal point slag rare behind the blow off.

3. terminal point pretreatment of slag technique as claimed in claim 1, it is characterized in that for closing on the heat that blow end point slag (FeO) content is high, slag is thin, before the converter terminal blow off, added blended stock or the synthetic material of fusing assistant and reductive agent in 1-2 minute in the stove by feed bin, guaranteeing that the terminal point slag has under the prerequisite of abundant good fluidity before the blow off, making (FeO) appropriateness reduction reduction in the slag.

As fusing assistant as described in the claim 1,2 or 3 be that converter steelmaking possesses shoddye, changes slag, the natural materials of the function of fluxing or synthetic material.

5. be a kind of of C matter reductive agent, carborundum powder, silicon calcium powder such as reductive agent as described in claim 1 or 3.

6. such as fusing assistant add-on≤4kg/ ton steel as described in the claim 1,2 or 3.

7. such as fusing assistant and reductive agent blended stock or its synthetic material add-on≤5kg/ ton steel as described in claim 1 or 3, reductive agent net content≤1kg/ ton steel wherein, the dosage of fluxing is 0-4.0kg/ ton steel.