CN101560586B - Compound dephosphorization agent with converter slag as raw material and preparing method thereof - Google Patents

Abstract

The invention discloses a molten iron pretreatment compound dephosphorization agent with converter slag as the raw material, and the compound dephosphorization agent contains the following raw materials by weight: 45 to 55 percent of converter slag, 3 to 5 percent of quartz sand, 22 to 34 percent of steel-rolling iron sheet, 3 to 6 percent of bauxite, 10 to 14 percent of soda and 0 to 5 percent offluorite; the raw materials meeting the ingredient demands are evenly mixed according to the proportions after being crushed, and then the product with the diameter being 20 to 50mm is produced after ball-milling, screen separation, palletizing and drying. The compound dephosphorization agent realizes cyclic utilization of the converter slag which accounts for 45 to 55 percent, thus reducing the produced slag amount in the steel-making process and the environmental load; the converter slag contains plenty of CaO and FeO, which can reduce consumption of lime to a certain degree, thus increasing the metal yield rate and reducing the steel-making cost; the compound dephosphorization agent has low melting point, slag can be formed fast, the liquidity is good, thus shortening the treatment time, the dephosphorizing efficiency is high, and the dephosphorized final slag has low alkalinity and low melting point.

Description

It with the converter slag compound dephosphorization agent of raw material and preparation method thereof

Technical field

The present invention relates to hot metal pretreatment compound dephosphorization agent that a kind of field of metallurgy uses and preparation method thereof, especially is hot metal pretreatment compound dephosphorization agent of basic material and preparation method thereof with the steel-making converter slag.

Background technology

China's Iron And Steel Industry develop rapidly in recent years, output of steel increases year by year, and the metallurgical slag output that derives thus is also unprecedented soaring, and only the annual output of converter slag promptly reaches tens million of tons.It is increasing to accumulate the converter slag of storing up and increasing newly, not only causes the serious waste of resource, also takies tract and pollutes surrounding enviroment.Because the utilization of converter slag still lacks effective approach, its comprehensive utilization becomes a significant problem of world's common concern.

From the angle of developing a circular economy, converter slag is a kind of ideal comprehensive utilization mode in the inner reuse of iron and steel enterprise.Contain a large amount of quicklime and red stone in the converter slag, alkaline condition and certain oxygen position can be provided, satisfy the requirement of dephosphorization, substituting the existing dephosphorizing agent of part with converter slag is feasible in theory.Converter slag belongs to the fritting material simultaneously, and chemical ingredients is comparatively uniform and stable, can play and change slag in advance, shortens the heat, and reduces the effects such as corrosive effect of blowing initial stage to furnace lining.

Carrying out liquid iron pretreatment dephosphorizing for the lime dephosphorizing agent with addition of converter slag has at present had the metallargist to study; But mostly be in the solid synthetic slag with addition of powdery or block converter slag; Thereby have an inevitable shortcoming: (1) converter slag basicity is high, and fusing point is high, with addition of after the dephosphorization thinner slag time long; Dephosphorization speed is lower, increase time and temperature drop; (2) the synthetic dephosphorizing agent of solid that contains converter slag is with addition of a large amount of quickened limes, and the moisture absorption is unfavorable for accumulating easily; (3) because granularity, density variation are bigger, be prone to produce component segregation, cause the dephosphorizing agent unstable properties, cause the rephosphorization phenomenon sometimes.

Reasons such as the fritting dephosphorizing agent that contains converter slag is then because processed complex, and is with high costs are not used widely yet.Converter slag is returned the instead of part dephosphorizing agent, can reduce a large amount of slag former consumption, obtain considerable economic.Reduce smelting process slag quantum of output simultaneously, account for the farmland pollution abatement less, for improving China's Iron And Steel Industry resource, energy utilization rate, the energy-output ratio that reduces product to greatest extent also has its own strategic significance.

Summary of the invention

It is the hot metal pretreatment compound dephosphorization agent of raw material with the converter slag that the technical problem that the present invention solved is to provide a kind of, effectively utilizes the beneficiating ingredient in the converter slag, promotes quick slagging, reduces and produces composition, reduces waste sludge discharge.Another object of the present invention provides the method for the said composite fluxing medium of preparation.

The object of the invention is realized through following technical scheme: a kind of is the hot metal pretreatment compound dephosphorization agent of raw material with the converter slag, by starting material mixed preparing such as converter slag, silica sand, steel rolling iron sheet, bauxitic clay, soda, fluorites.This dephosphorizing agent is characterized in that the finished product that makes is to satisfy following weight percent: converter slag 45～55%, silica sand 3～5%, steel rolling iron sheet 22～34%, bauxitic clay 3～6%, soda 10～14%, fluorite 0～5%.

For guaranteeing this compound dephosphorization agent stable performance and ability slagging fast, wherein the chemical constitution of raw material (weight %) satisfies respectively:

Converter slag: CaO/SiO ₂2.5～3.5, P ₂O ₅≤3%;

Silica sand: SiO ₂>=95%;

Steel rolling iron sheet: FetO >=70%;

Bauxitic clay: Al ₂O ₃>=65%, SiO ₂≤20%;

Soda: Na ₂CO ₃>=95%;

Fluorite: CaF ₂>=85%, SiO ₂≤5%.

What the present invention relates to is that the preparation method of the hot metal pretreatment compound dephosphorization agent of raw material comprises following steps with the converter slag:

1) chemical ingredients of detection starting material converter slag, silica sand, steel rolling iron sheet, bauxitic clay, soda and fluorite;

2) various raw material crushings are become the particle of 10～30mm with crusher;

3) raw material that fragmentation is good is by prescription requirements mixing, and is levigate and mix with ball mill;

4) with 100 eye mesh screens the raw material that mixes is sieved;

5) add an amount of water glass as sticker, wilkinite or glass and bentonitic mixture, and make ball with the ball press pressurization;

6) send the granulation material to drying bed and carry out drying, pack for use, finished diameter 20～50mm.

Compared with prior art, the present invention has the following advantages:

(1) realized the recycle of converter slag, converter slag accounts for 45～55% in the compound dephosphorization agent, has reduced the product quantity of slag of steelmaking process, has reduced carrying capacity of environment;

(2) contain a large amount of CaO and FeO in the converter slag, can reduce lime consumption to a certain extent, improve recovery rate of iron, thereby reduce steel-making cost;

(3) the compound dephosphorization agent fusing point is low, slagging fast, and good fluidity can effectively shorten the treatment time;

(4) the compound dephosphorization agent phosphate capacity is big, and dephosphorization efficient is high, high phosphorus hot metal converter dephosphorization in can be applicable to;

(5) use compound dephosphorization thinner slag all right, dephosphorization finishing slag basicity is low, and the free oxidation calcium contents is few;

(6) can alleviate the anti-material of furnace lining corrodes;

(7) the dephosphorizing agent slag system is complicated, and fusing point is low, can not add fluorite and flux, and the realization dephosphorizing agent does not have to be fluoridized;

(8) be difficult for the moisture absorption, relatively accumulating;

(9) preparation method of the present invention is simple, and is convenient feasible.

Embodiment

Embodiment of the present invention is following:

A kind of is the hot metal pretreatment compound dephosphorization agent of raw material with the converter slag, is made up of following raw material and weight percent thereof: converter slag 45～55%, silica sand 3～5%, steel rolling iron sheet 22～34%, bauxitic clay 3～6%, soda 10～14%, fluorite 0～5%.The starting material that satisfy the composition requirement mix after fragmentation according to the above ratio, through ball milling, sieve, make ball, process the finished product of diameter 20～50mm after dry.During the hot metal pretreatment operation, it is steel 15～25Kg per ton that compound dephosphorization agent adds total amount.During use it is dropped in steel scrap hopper, disposablely add with steel scrap.According to situation in the stove, add lime and dissolving agent subsequently in good time, with slag terminal point Composition Control in target zone.Converter slag is the metallurgical slag that smelting industry produces, and contains effective constituents such as a large amount of quicklime and red stone; The chemical formula of steel rolling iron sheet is FetO, is the waste material that produces after the steel rolling; Silica sand, bauxitic clay, soda, fluorite are metallurgical slag making material commonly used.

For guaranteeing this compound dephosphorization agent stable performance and ability slagging fast, wherein the chemical constitution of raw material (weight %) satisfies respectively:

Converter slag: CaO/SiO ₂2.5～3.5, P ₂O ₅≤3%;

Silica sand: SiO ₂>=95%;

Steel rolling iron sheet: FetO >=70%;

Bauxitic clay: Al ₂O ₃>=65%, SiO ₂≤20%;

Soda: Na ₂CO ₃>=95%;

Fluorite: CaF ₂>=85%, SiO ₂≤5%.

Through the form of embodiment, foregoing of the present invention is remake further detailed description below.But should this be interpreted as that the scope of the above-mentioned theme of the present invention only limits to following instance.All technology that realizes based on foregoing of the present invention all belong to scope of the present invention.

Embodiment 1:

In the present embodiment, the composition of compound dephosphorization agent and weight percent are: converter slag 54%, steel rolling iron sheet 24%, silica sand 3%, bauxitic clay 6%, soda 13%.Can improve slag fluidity owing to contain a certain amount of soda in the present embodiment, based on environment protection and the purpose that reduces lining erosion, present embodiment does not add fluorite.After processing finished product by aforesaid method, according to measured result, the dephosphorizing agent dual alkalinity is about 1.85, and hemisphere point temperature is 1241 ℃, satisfies the requirement of molten iron temperature generally.Double slag process is adopted in test, promptly carries out the operation of low temperature dephosphorization earlier, and one pours out the segment converter slag when falling, and adds slag former again and carries out the decarburization blowing.Present embodiment only uses compound dephosphorization agent in the dephosphorization stage.During use the 2t compound dephosphorization agent is dropped in the steel scrap hopper, get into the 80t converter, add quickened lime and dissolving agent in the converting process gradually with steel scrap.The molten iron add-on is 77～79 tons in every stove, and adding amount of scrap steel is 9～11 tons in every stove.Molten iron phosphorus content 0.11～0.13%.10 heats are carried out in test altogether, and 5 stoves adopt compound dephosphorization agent.Be comparative analysis, other 5 stoves directly add the 1.5t converter slag with steel scrap.Result of implementation is seen table 1.

Table 1 result of implementation

See that from table 1 the half steel phosphorus content when using compound dephosphorization agent is starkly lower than direct use when returning slag, has obtained tangible dephosphorization effect.Simultaneously, from result of use, slagging is fast when using compound dephosphorization agent, and scrap melting is complete.Compound dephosphorization agent forms the melt cinder with better flowability fast, and follow-upization slag is all right, is beneficial to the dissolving of lime.

Embodiment 2:

In the present embodiment, the composition of compound dephosphorization agent and weight percent are: converter slag: 50%, steel rolling iron sheet 26%, silica sand 3%, bauxitic clay 4%, soda 12%, fluorite 5%.After processing finished product by aforesaid method, through measuring, the dephosphorizing agent dual alkalinity is about 1.8, and hemisphere point temperature is 1235 ℃, satisfies the requirement of molten iron temperature generally.Under 1350 ℃ simulation dephosphorization condition, it is all right to change slag.

Embodiment 3:

In the present embodiment, the composition of compound dephosphorization agent of the present invention and weight percent are: converter slag: 46%, steel rolling iron sheet 33%, silica sand 5%, bauxitic clay 3%, soda 10%, fluorite 3%.After processing finished product by aforesaid method, through measuring, the dephosphorizing agent dual alkalinity is about 1.75, and hemisphere point temperature is 1232 ℃, satisfies the requirement of molten iron temperature generally.Under 1350 ℃ simulation dephosphorization condition, it is all right to change slag.

Embodiment 4: the composition of compound dephosphorization agent of the present invention and weight percent are: converter slag: 45%, steel rolling iron sheet 34%, silica sand 4%, bauxitic clay 6%, soda 10%, fluorite 1%.After processing finished product by aforesaid method, under 1350 ℃ simulation dephosphorization condition, it is all right to change slag.

Embodiment 5: the composition of compound dephosphorization agent of the present invention and weight percent are: converter slag: 55%, steel rolling iron sheet 28%, silica sand 3%, bauxitic clay 4%, soda 10%, fluorite 0%.After processing finished product by aforesaid method, under 1350 ℃ simulation dephosphorization condition, it is all right to change slag.

The invention is not restricted to the foregoing description, experiment showed, through the contriver in formula range of the present invention, all can reach the object of the invention.

Claims (3)

1. one kind is the compound dephosphorization agent of raw material with the converter slag, and it is characterized in that: said dephosphorizing agent contains the component of following weight per-cent, converter slag 45～55%; Silica sand 3～5%, steel rolling iron sheet 22～34%, bauxitic clay 3～6%; Soda 10～14%, fluorite 0～5%;

The effective constituent CaO of said converter slag and SiO ₂Content ratio, CaO/SiO ₂Be 2.5～3.5;

P in the said converter slag ₂O ₅≤3%.

2. according to claim 1 and 2 is the compound dephosphorization agent of raw material with the converter slag, it is characterized in that the effective constituent weight percent is in all the other components:

Silica sand: SiO ₂>=95%;

Steel rolling iron sheet: FetO >=70%;

Bauxitic clay: Al ₂O ₃>=65%, SiO ₂≤20%;

Soda: Na ₂CO ₃>=95%;

Fluorite: CaF ₂>=85%, SiO ₂≤5%.

3. a claim 1 is described is the preparation method of the compound dephosphorization agent of raw material with the converter slag, it is characterized in that may further comprise the steps:

1) chemical ingredients of detection starting material converter slag, silica sand, steel rolling iron sheet, bauxitic clay, soda and fluorite;

2) various raw material crushings are become the particle of 10～30mm with crusher;

3) raw material that fragmentation is good is by prescription requirements mixing, and is levigate and mix with ball mill;

4) with 100 eye mesh screens the raw material that mixes is sieved;

5) add water glass, wilkinite or water glass and bentonitic mixture, and pressurize with ball press and to make ball as sticker;

6) send the granulation material to drying bed and carry out drying, pack for use, finished diameter 20～50mm.