CN1048284C

CN1048284C - Safety working method for remained converter slag

Info

Publication number: CN1048284C
Application number: CN95110987A
Authority: CN
Inventors: 王虎
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-03-28
Filing date: 1995-03-28
Publication date: 2000-01-12
Anticipated expiration: 2015-03-28
Also published as: CN1132255A

Abstract

The present invention discloses a method for carrying out remained slag operation for converter steelmaking, which has the main technical scheme that reducing agents containing charcoal, such as coal dust or coke or graphite, etc., are added to the surface of slag liquid in a converter before tapping in the converter or in the process of tapping to deacidize FeO in the slag liquid to increase the viscosity of slag and ensure the security of the remained slag operation. The method has the advantages of simplicity and easiness, low cost and obvious converter steelmaking cost reduction.

Description

A kind of safety working method for remained converter slag

The present invention relates to a kind of converter safety and stay the method for slag operation.

The high basicity oxidation sludge that generates behind the converter refining has very high dephosphorization performance, and contains the composition that a large amount of ∑ (FeO), MFe, CaO etc. have recovery value, and a large amount of sensible heats.The slag operation is stayed in enforcement, can reduce the steel-making operating cost significantly.The 60 to 70's China's steel industry was once implemented the remained converter slag operation, but it is higher to contain ∑ (FeO) in the slag because of ∑ in the finishing slag (FeO) content height, especially soft steel, good fluidity, repeatedly spray the slag casualty accident during converter hot metal charging, have to yield and stay the slag operation.

Spray slag reason takes place during remained converter slag operation hot metal charging is: Reaction produces a large amount of CO bubble floatings in instantaneous, and takes a large amount of outer sprays of slag and accidents caused.Suppress to spray slag, key is the reaction between (FeO)-[C] when suppressing hot metal charging.Originally studies show that, under the converter smelting condition, suppress above-mentioned reaction, its key is the velocity of diffusion of control (FeO) again.Because (FeO)-[C] reaction is first order reaction, speed of response V=K _D(C _FeO°-C _FeO')=C/ η (C _FeO°-C _FeO') (because K _Dη=C).K in the formula _DBe (FeO) diffusion constant in the slag, η is a slag viscosity, C _FeO° be (FeO) concentration in the slag, C _FeO' be (FeO)-[C] the surface reaction concentration of (FeO) at the interface that C is a constant.From the product of reaction as seen, improve CO dividing potential drop P in the furnace gas _COCan suppress (FeO)-reaction between [C].From the speed of response formula, as seen, increase the sticking useless η of slag, reduce (FeO) concentration C in the slag _FeO°, can reach the purpose of inhibited reaction.Because depending on slag, slag viscosity forms and the bits temperature.Improve slag melting or reduce slag temperature, in slag, add the solid particulate of disperse, slag viscosity is improved.Analyze and the discovery of relevant research data according to the FeO-SiO-CaO ternary phase diagrams, when basicity of slag (CaO/SiO) timing, ∑ in the slag (FeO) reduction by 10% ±, slag melting rises 200～350 ℃.As shown in Figure 1, during basicity R=4.TFe reduces to 15% from 18%, and slag melting rises to 1600 ℃ from 1400 ℃; TFe reduces to 10% o'clock slag melting by 15% again and rises to 1760 ℃ from 1600 ℃.Therefore, the ∑ (FeO) as if reducing effectively in the slag just can reach the raising slag melting simultaneously, increases slag viscosity, reduces the double effects of ∑ in the slag (FeO) simultaneously.(FeO)-[C] the speed of response V=K between _D(C _FeO°-C _FeO') then be K _D, C _FeOThe product amplitude of ° reduction value reduces sharply, and its effect is much larger than the effect of simple reduction bits temperature.For this reason, some in recent years producers successively organized the test of adding (FeO) in the coke powder reducing slag in staying slag.As above steel five Yang Xing of factory woodss " remained converter slag steel-making discussion " (" iron and steel " the 26th volume fifth phase, in May, 1991), " slag operation is stayed in converter steelmaking " of the Zhang Yicai of Nanjing Steel ﹠ Iron Plant (" iron and steel " 1991), and people such as Mai Guoru " Tang Gang two steel-making 30T remained converter slags steel-making Test Summaries " (" Tang Gang science and technology ", 1989) etc. all propose in the literary composition to reduce the method for finishing slag (FeO) with coke powder, but (FeO) reduction effect is undesirable, in most test heat slags (FeO) also commercial weight be 2～3%, indivedual heats are 5～6%.So that above-mentioned technology not practical application so far.The external useful ∑ in the aluminium waste reducing slag (FeO) that contains, but cost is higher.

Of the present inventionly be to provide a kind of in the remained converter slag operation, suppress the reaction between (FeO)-[C], prevent from the hot metal charging process, to take place the method for spray slag.

It is such that safety of the present invention is stayed the slag operational method: behind the converter steelmaking blow off, use spraying machine slag liquid jet surface carbon containing reducer in stove before tapping or in the tapping process, behind the prereduction slag; Look the crust block situation of slag, before closing on tapping and finishing or can carry out secondary to the slag surface after finishing and mend carbon, in stove, add part lime afterwards, implement to stay the slag operation.

Described carbon containing reducer is one of powdered graphite, coke, coal, and its powdered granule diameter is less than 5mm, spray at every turn carbon containing also the amount steel per ton of agent be 0.5～2Kg.

Accompanying drawing 1 is a basicity of slag R-fusing point graph of a relation.

Embodiment: not tapping immediately behind the converter blow off, but in stove, add coke powdery carbon containing reducer earlier, an add-on is at steel 1.2Kg per ton, because body of heater is in steel-supplying position, the slag spreading area is big, slag blanket is thin, coke powder evenly sprays in addition, and coke powder and (FeO) interfacial area are increased greatly, simultaneously because the coke powder amount that sprays into few (the ton steel is at 1.2Kg), the Physical temperature-lowering that slag is produced is little, this moment, slag viscosity was little, and (FeO) velocity of diffusion is fast, and the CO bubble of generation is easily overflowed, therefore the reaction between C-(FeO) is more abundant, and (FeO) descends significantly in the slag thereby can make.And C all is used for the reduction of (FeO), not carburetting of molten steel, (P in the slag ₂O ₅) also do not reduce.In addition, consider that the coke powder of disperse also can improve slag viscosity effectively, in case the CO bubble that forms plays the broken bubble effect of machinery, and keep certain P in the stove in the time of simultaneously also can be hot metal charging _CO, can also increase the ability of eating steel scrap.So finish forward direction slag surface secondary and add coke powder closing on tapping, mend amount near primary straying quatity, add 10% lime of one heat steel lime consumption subsequently, implement to stay the slag operation.The variation of slag composition saw Table 1 before and after spray contained C reductive agent reduced blast furnace before the tapping.

Spray into before table 1. tapping and contain the composition variation of C reductive agent slag reduction front and back.

Slag composition %	CaO	SiO ₂	Al ₂O ₃	MnO	FeO	P ₂O ₅	S
Slag composition %	CaO	SiO ₂	Al ₂O ₃	MnO	FeO	P ₂O ₅	S	Before the slag reduction	53	13	2.0	2.2	26	2.1	0.09
After the slag reduction	58	14	2.2	2.0	15	2.2	0.10	Before the slag reduction	53	13	2.0	2.2	26	2.1	0.09

Technology of the present invention is simple, and device simple is with low cost; Can guarantee fully that converter implements safety and stay the slag operation, thereby the converter steelmaking operating cost is significantly reduced, have huge economic benefit.

Claims

1, a kind of converter safety is stayed the slag operational method, it is characterized in that: behind the converter steelmaking blow off, with spraying machine slag liquid jet surface carbon containing reducer in stove, tap behind the prereduction slag before tapping or in the tapping process; In stove, add part lime afterwards, implement to stay the slag operation.

2, safety as claimed in claim 1 gives over to industry method, it is characterized in that: mend carbon to slag surface secondary before tapping closes on end or after finishing, interpolation part lime in stove implements to stay the slag operation afterwards.

3, safety as claimed in claim 1 is stayed the slag operational method, it is characterized in that: described reductive agent is a kind of in graphite, coke, the coal, and its powdered granule diameter is less than 5mm, and the amount steel per ton that at every turn sprays carbon containing reducer is 0.5～2Kg.