CN103789496A - Preparation method of pre-melted dephosphorization agent for converter steelmaking - Google Patents

Abstract

The invention discloses a preparation method of a pre-melted dephosphorization agent for converter steelmaking. The dephosphorization agent is composed of the following components by weight: 20-24 parts of Fe2O3, 42-46 parts of CaO, 6-8 parts of Al2O3, 5-9 parts of SiO2, 2-4 parts of Na2CO3, and 4-8 parts of B2O3. The preparation method comprises the steps of: 1) weighing materials according to the proportion; 2) conducting pre-melting treatment, placing the well proportioned components into a furnace, performing heating to 1300-1350DEG C, after all the components are melted, stirring the components evenly and further carrying out melting for 20-30min, and then conducting natural cooling; 3) crushing the cooled pre-melted material to less than 1mm; 4) putting the crushed pre-melted material into a ball mill to conduct ball milling to -40 meshes; and 5) subjecting the ball-milled pre-melted material to vacuum packaging.

Description

The preparation method of pre-molten dephosphorizing agent for a kind of converter steelmaking

Technical field

The present invention relates to ferrous metallurgy auxiliary material technical field, relate in particular to the preparation method of a kind of converter steelmaking pre-molten dephosphorizing agent.

Background technology

Phosphorus harmful element normally in steel, because phosphorous height can make steel produce cold short phenomenon and affect some mechanical propertys of steel in steel, therefore will strictly control.In conventional art, the phosphorus general requirement in steel is controlled at below 0.012%, and along with the raising of some steel grade mechanical property requirement standard, the phosphorus in some Clean Steels and ultra-low phosphoretic steel must be controlled at 0.005% left and right, or even below 0.003%.For realizing this goal, steel mill adopts " double slag process " in converter smelting, to adopt twice slag making or " two step method " both to take a block converter to smelt forwarding to after dephosphorization of molten iron in another converter mostly.These two kinds of phosphorus removing methods are all that operation is loaded down with trivial details, the treatment time is long, and the tissue of producing to converter has brought difficulty with coordinating of continuous casting.The method of converter current dephosphorization is mainly interpolation lime and adds flux material.It is generally acknowledged CaF ₂to 2CaOSiO ₂and 3CaOSiO ₂and the rapid melting of lime has important promoter action, it is also one of in the past conventional flux material.But, due to CaF ₂human body and environment are had to strong corrosive nature, and most smelter does not re-use.In addition, in order to improve the FeO concentration in slag, all adopt the mode of Fe element in oxygen blast oxidation steel to solve at present.But because the oxidation of Fe element is also thermopositive reaction, can make the temperature of molten metal raise, also be unfavorable for the carrying out of dephosphorisation reaction.Meanwhile, the method that improves FeO in slag by Fe in oxidation steel, also can make recovery rate of iron reduce.

Chinese patent (patent No. 99112573.8) discloses a kind of iron scale class dissolving agent take FeO as chief component, it consists of: iron scale 70～90%, ironmaking sludge 5～25%, binding agent 1～5%, by raw material pulverizing, configure, mix and suppress balling-up, iron scale class dissolving agent slag effect is comparatively remarkable, but exist serious to lining erosion, make temperature drop large, action time short can not ensured sustained development slag etc. problem.

Summary of the invention

The preparation method who the object of the invention is to propose a kind of converter steelmaking pre-molten dephosphorizing agent, dephosphorizing agent dephosphorization effect prepared by the method is good, and environmental pollution is little, and fusing point is low and stable, and floride-free, to overcome the defect of prior art.

For reaching this object, the present invention by the following technical solutions:

A preparation method for pre-molten dephosphorizing agent for converter steelmaking, described dephosphorizing agent is made up of following component in weight part: Fe ₂o ₃20-24 part, CaO 42-46 part, Al ₂o ₃6-8 part, SiO ₂5-9 part, Na ₂cO ₃2-4 part, B ₂o ₃4-8 part; Described preparation method comprises the steps:

1) by said ratio weigh batching;

2) fritting processing, puts into the good said components of proportioning to add stove, is warming up to 1300-1350 ℃, after whole component melts, stirs and continues melting 20-30 minute, then naturally cooling again;

3) fragmentation, is crushed to cooled pre-melt to be less than 1mm;

4) ball-milling processing, puts into ball mill by the pre-melt after fragmentation, is milled to-40 orders;

5) by the pre-melt vacuum packaging after ball milling.

Compared with prior art, the present invention has following beneficial effect:

1) combination that the present invention utilizes boron oxide and sodium carbonate substitutes Calcium Fluoride (Fluorspan) completely, has thoroughly eliminated fluorine-containing pollution on the environment in current dephosphorizing agent, and dephosphorization effect is also more remarkable than adopting Calcium Fluoride (Fluorspan) to make the dephosphorization effect of dephosphorizing agent of fusing assistant.

2) dephosphorizing agent of the present invention, dephosphorization effect is stable, consumes lowly, can make the phosphorus in steel be reduced to below 0.003%.

3) on the basis of great many of experiments, determine the content of boron oxide and sodium carbonate, make the fusing point of dephosphorizing agent lower than 1250 ℃.

4) preparation method is simple, adopts vacuum packaging, has avoided the impact that dephosphorizing agent result of use is caused such as air-breathing of the moisture absorption in storage and transportation.

Embodiment

Further illustrate technical scheme of the present invention below in conjunction with embodiment.

Embodiment mono-

A preparation method for pre-molten dephosphorizing agent for converter steelmaking, described dephosphorizing agent is made up of following component in weight part: Fe ₂o ₃20 parts, 46 parts of CaO, Al ₂o ₃6 parts, SiO ₂9 parts, Na ₂cO ₃2 parts, B ₂o ₃8 parts; Described preparation method comprises the steps:

1) by said ratio weigh batching;

2) fritting processing, puts into the good said components of proportioning to add stove, is warming up to 1300 ℃, after whole component melts, stirs and continues melting 30 minutes, then naturally cooling again;

3) fragmentation, is crushed to cooled pre-melt to be less than 1mm;

4) ball-milling processing, puts into ball mill by the pre-melt after fragmentation, is milled to-40 orders;

5) by the pre-melt vacuum packaging after ball milling.

Embodiment bis-

A preparation method for pre-molten dephosphorizing agent for converter steelmaking, described dephosphorizing agent is made up of following component in weight part: Fe ₂o ₃24 parts, 42 parts of CaO, Al ₂o ₃8 parts, SiO ₂5 parts, Na ₂cO ₃4 parts, B ₂o ₃4 parts; Described preparation method comprises the steps:

1) by said ratio weigh batching;

2) fritting processing, puts into the good said components of proportioning to add stove, is warming up to 1350 ℃, after whole component melts, stirs and continues melting 20 minutes, then naturally cooling again;

3) fragmentation, is crushed to cooled pre-melt to be less than 1mm;

4) ball-milling processing, puts into ball mill by the pre-melt after fragmentation, is milled to-40 orders;

5) by the pre-melt vacuum packaging after ball milling.

Embodiment tri-

A preparation method for pre-molten dephosphorizing agent for converter steelmaking, described dephosphorizing agent is made up of following component in weight part: Fe ₂o ₃22 parts, 44 parts of CaO, Al ₂o ₃7 parts, SiO ₂7 parts, Na ₂cO ₃3 parts, B ₂o ₃6 parts; Described preparation method comprises the steps:

1) by said ratio weigh batching;

2) fritting processing, puts into the good said components of proportioning to add stove, is warming up to 1325 ℃, after whole component melts, stirs and continues melting 25 minutes, then naturally cooling again;

3) fragmentation, is crushed to cooled pre-melt to be less than 1mm;

4) ball-milling processing, puts into ball mill by the pre-melt after fragmentation, is milled to-40 orders;

5) by the pre-melt vacuum packaging after ball milling.

Claims (1)

1. a preparation method for pre-molten dephosphorizing agent for converter steelmaking, is characterized in that, described dephosphorizing agent is made up of following component in weight part: Fe ₂o ₃20-24 part, CaO 42-46 part, Al ₂o ₃6-8 part, SiO ₂5-9 part, Na ₂cO ₃2-4 part, B ₂o ₃4-8 part; Described preparation method comprises the steps:

1) by said ratio weigh batching;

2) fritting processing, puts into the good said components of proportioning to add stove, is warming up to 1300-1350 ℃, after whole component melts, stirs and continues melting 20-30 minute, then naturally cooling again;

3) fragmentation, is crushed to cooled pre-melt to be less than 1mm;

4) ball-milling processing, puts into ball mill by the pre-melt after fragmentation, is milled to-40 orders;

5) by the pre-melt vacuum packaging after ball milling.