CN103866131A

CN103866131A - Method for recycling blast furnace fly ash containing zinc

Info

Publication number: CN103866131A
Application number: CN201410092856.6A
Authority: CN
Inventors: 李士琦; 徐刚; 王玉刚; 纪志军; 唐小辉; 徐凯; 杨静波; 肖洪; 贾凤娟; 张文强; 曹悦霞; 张�杰
Original assignee: University of Science and Technology Beijing USTB
Current assignee: University of Science and Technology Beijing USTB
Priority date: 2014-03-13
Filing date: 2014-03-13
Publication date: 2014-06-18
Anticipated expiration: 2034-03-13
Also published as: CN103866131B

Abstract

A method for recycling zinc-containing blast furnace dust, which belongs to the field of iron and steel production, and is characterized in that: the reduction temperature, reduction atmosphere and reduction time are controlled, and zinc, iron The oxides are reduced, and since the reduction temperature is lower than 1050°C, sintering and melting do not occur during the reduction process. The zinc produced by reduction escapes in gaseous form and is collected by the dust collection device to obtain zinc-rich products. The powdered iron produced by reduction exists in the solid residue and can be used to prepare desulfurizers without secondary solid waste pollution. In the present invention, the zinc-containing blast furnace dust is reduced at a temperature lower than 1050°C. No melting or sintering occurs during the reduction process. After reduction, the solid iron-rich residue and the gaseous volatile high-zinc product are still powdery materials without sintering. The process can The consumption is very low, no secondary solid waste such as slag is generated, the environment is friendly, and it has good economic benefits.

Description

A kind of containing zinc blast furnace dedusting ash renewable resources treatment process

Technical field

The invention belongs to the reutilization field of the solid waste of Iron and Steel Production, specifically containing zinc blast furnace dedusting ash renewable resources method.

Background technology

One ton of pig iron of every production in iron and steel flow process taking iron ore as raw material, the about 10Kg blast furnace dedusting ash of corresponding generation, wherein contain ferro element and a certain amount of zinc element of 30% left and right, be respectively: low zinc dedusting ash (Zn < 1%), in low zinc dedusting ash (1% < Zn < 4%), middle zinc dedusting ash (4% < Zn < 8%), middle high zinc dedusting ash (8% < Zn < 20%), five grades of high zinc dedusting ash (20% < Zn).

China produces approximately 600,000,000 tons of the pig iron every year in recent years, producing blast furnace dedusting ash is 6,000 ten thousand tons, this is the flood tide solid waste to severe environmental pollution, the application is carried out renewable resources processing, not only greatly alleviate the carrying capacity of environment of iron and steel enterprise, annual also obtainable stock number is: 1,800 ten thousand tons of ferro elements, 2,400,000 tons of zinc element, bring considerable economic benefit.

At present, process and have following several containing zinc blast furnace dedusting ash main method:

(1) directly return as raw materials for sintering: be only applicable to process low zinc blast furnace dedusting ash.Main drawback has: iron grade and the strength decreased of agglomerate; In dust, contain the element such as potassium, sodium and increase ironmaking alkali load; The ventilation property variation of the bed of material, production capacity declines.

(2) curing or landfill: this method is prohibited gradually.Not only land occupation resource, causes environmental pollution, and in dedusting ash, iron, zinc resource are not recycled and waste.

(3) rotary kiln or rotary hearth furnace technology, this technology is comparatively ripe, zinc, iron resources in energy recycled dust removing ashes.But treating processes temperature high (1200 DEG C ~ 1350 DEG C), energy consumption are large; Need to carry out the pre-treatment such as agglomeration (ball), additionally with addition of coal dust, cost is higher; Burning and reduction, in a space reactor, cause the reductibility of atmosphere not high, and the degree of metalization of iron and dezincify rate are not high.Rotary hearth furnace can only be processed the lower and higher dedusting ash of iron level of zinc content; The easy ring formation of rotary kiln technology in addition, the eccentric grade of rotary hearth furnace equipped problems affect production direct motion.

(4) technology is soaked in acid (alkali), can only process middle and high zinc dedusting ash, and the leaching yield of zinc is low, soak in slag remaining zinc content higher, steel mill is difficult to recycle soaking slag, a large amount of leaching agents that consume in production, equipment corrosion is serious, working condition is poor, and production cost is high, and in technique, the introducing of sulphur, chlorine causes new environmental pollution.

Summary of the invention

The present invention is using blast furnace ironmaking dedusting ashes as resource, and mean particle size is 20um(1um ~ 100um), the meticulous reduction technique that is applicable to invention gives renewable resources.

A kind of containing zinc blast furnace dedusting ash renewable resources treatment process, it is characterized in that controlling reduction temperature, reducing atmosphere and recovery time, in meticulous reducing apparatus, will be reduced through zinc, ferriferous oxide in pretreated dedusting ash, the zinc that reduction generates leaves solid residue with gaseous form volatilization, the iron that reduction generates is present in solid residue with solid-state form, use particle collector to carry out condensation enrichment to it, reach the separation and concentration effect of zinc and iron, reduzate is carried out to aftertreatment and do not produce secondary solid waste.

(1) pre-treatment: obtain siccative fine dust after will drying, and simply grind, sieve containing zinc blast furnace dedusting ash, its control parameter is:

1) bake out temperature: 120 ± 10 DEG C;

2) sieve specification: 100 orders, remove large granular materials.

(2) control reduction: the siccative dust that pre-treatment is obtained is placed in meticulous reducing apparatus and passes into reducing gas and reduced, it is controlled parameter and is:

1) reduction temperature: 900 ~ 1050 DEG C;

2) gas reduction:

;

3) recovery time: fixed bed 1 ~ 2h, moving-bed 10 ~ 20min;

Reducing gas is blast furnace gas or hydrogen, and its reductibility is decided to be

Figure 2014100928566100002DEST_PATH_IMAGE002

, for ensureing its enough strong reductibility, need be to the blast furnace gas processing of reforming, reformation parameter is:

1) reformation agent: blue carbon or coke (fixed carbon >=80%);

2) reforming temperature: 950 ~ 1200 DEG C.

(3) meticulous reduction: the solid residue that meticulous reduction produces is about 50% ~ 70% of initial material amount, allocates appropriate lime into and makes the agent of steel-making refining desulfuration, controls parameter and is:

1) lime composition: CaO >=80%;

2) quaternary basicity in finished product sweetening agent: 2 ~ 3;

3) in finished product sweetening agent: FeO≤1%;

The enrichment of the high zinc volatility product that meticulous reduction produces: the zinc after reduction is overflowed with gaseous form volatilization at 900 ~ 1050 DEG C, coolingly obtains by its enrichment the rich zinc product that purity is higher through particle collector, wherein contains 10% ~ 15% KCl, leachable through washing.

The meticulous reduction moving-bed device using with above-mentioned complete sets of Techniques and fixed bed device as shown in accompanying drawing 1, accompanying drawing 2, mainly comprise: 1 source nitrogen, 2 blast furnace coal sources of the gas respectively, 3 coal gas reforming furnaces, 4 gas meters, 5 gas mixing chambers, 6 moving-bed reduction furnaces, 7 housings, 8 thermopairs, 9 particle collectors, 10 sources of hydrogen, 11 fixed bed reduction furnaces, 12 crucibles.Gas pipeline connects source of the gas, under meter, gas mixing chamber, (moving-bed or fixed bed) reduction furnace, and electric wire connects housing, thermopair, (moving-bed or fixed bed) reduction furnace, and particle collector is fixed on air outlet.

The meticulous reduction process of its moving-bed is: pass into nitrogen protection; reduction furnace, reforming furnace heat up simultaneously; to preset temperature insulation; pass into blast furnace gas; add containing zinc blast furnace dedusting ash and reduce in reduction furnace by feeding mouth; after when reaching reduction, rich iron solid residue is discharged from discharge port, and the high zinc volatile matter of gaseous state is deposited on particle collector.

The meticulous reduction process of its fixed bed is: be placed in reduction furnace containing zinc blast furnace dedusting ash, pass into nitrogen protection, reduction furnace heats up; to preset temperature insulation; pass into hydrogen, reach cooling after the recovery time and take out rich iron solid residue, the high zinc volatile matter of gas is deposited on particle collector.

Advantage of the present invention will reduced lower than 1050 DEG C containing zinc blast furnace dedusting ash, there is not melting in reduction process, after reduction, obtaining the rich iron resistates of solid and the high zinc volatility product of gaseous state is still pulverulent material, all do not produce sintering, process energy consumption is very low, do not produce the secondary solid wastes such as slag, environmental friendliness degree is very high, and therefore economic benefit prospect is very good.

Brief description of the drawings

Fig. 1 is the meticulous reducing apparatus schematic diagram of moving-bed, and Fig. 2 is the meticulous reducing apparatus schematic diagram of fixed bed:

Note: 1 source nitrogen in figure, 2 blast furnace coal sources of the gas, 3 coal gas reforming furnaces, 4 gas meters, 5 gas mixing chambers, 6 moving-bed reduction furnaces, 7 housings, 8 thermopairs, 9 particle collectors, 10 sources of hydrogen, 11 fixed bed reduction furnaces, 12 crucibles.Gas pipeline connects source of the gas, under meter, gas mixing chamber, (moving-bed or fixed bed) reduction furnace, and electric wire connects housing, thermopair, (moving-bed or fixed bed) reduction furnace, and particle collector is fixed on air outlet.

Fig. 3 is for containing zinc blast furnace dedusting ash siccative particle size distribution figure:

Note: in figure, q is size-grade distribution; Q is cumulative distribution

Fig. 4 is containing solid residue particle size distribution figure after the meticulous reduction of zinc blast furnace dedusting ash:

Note: in figure, q is size-grade distribution; Q is cumulative distribution

concrete implementation content

Specific embodiment of the invention content is to pretreated Tang Gang ironmaking portion of group North 3# blast furnace dust 100g(TFe=32.6%, Zn=3.9%) carry out renewable resources processing:

(1) blast furnace dedusting ash pre-treatment: 120 DEG C of oven dry, simply grind, screening (100 order) obtains thin siccative 100g.

(2) containing the meticulous reduction of zinc blast furnace dedusting ash (fixed bed): by dedusting ash at 910 ~ 980 DEG C of temperature and pure H ₂reduced, in process, parameter control is as follows:

1) reduction temperature: 910 DEG C, 980 DEG C;

2) reducing atmosphere: pure H ₂;

3) recovery time: 1h, 2h.

After reduction, obtain solid residue 62.5g, wherein the degree of metalization of iron is more than 95%, and zinc content is below 0.1%, and dezincify rate is more than 98%, and before and after reduction, sintering phenomenon (seeing Fig. 3, Fig. 4) does not occur material.

(3) reduzate aftertreatment: allocate solid residue after reduction into appropriate lime and make refining desulfuration agent, control parameter as follows:

1) lime composition: CaO >=80%;

2) in finished product sweetening agent, quaternary is slowed down: 2 ~ 3;

3) in finished product sweetening agent: FeO≤1%;

Make sweetening agent 222.6g, can be used for making steel refining desulfuration agent.

Gaseous volatile after reduction is collected containing the rich zinc product 3.1g of zinc 72% by particle collector.

To the North 3# blast furnace dedusting ash 100g renewable resources processing of Tang Gang ironmaking portion, can obtain respectively the high zinc powder dirt 3.1g of refining desulfuration agent 222.6g and zinc content 72% by the present invention, realize containing the utilization of zinc blast furnace dedusting ash renewable resources.

Claims

1. A zinc-containing blast furnace dust removal recycling treatment method is characterized in that the reduction temperature, reduction atmosphere and reduction time are controlled, and zinc and iron oxides in the pretreated dust removal dust are reduced in a fine reduction device, and the reduction The generated zinc volatilizes away from the solid residue in gaseous form, and the iron generated by reduction exists in the solid residue in solid form, and is condensed and enriched by using a dust collection device to achieve the separation and enrichment effect of zinc and iron, which is beneficial to the reduction The post-processing of the product does not generate secondary solid waste; the specific implementation steps are as follows:

(1) Pretreatment: dry the zinc-containing blast furnace dust, simply grind and sieve to obtain dry material fine dust. The control parameters are:

1) Drying temperature: 120±10°C;

2) Sieve specification: 100 mesh, remove large particle materials;

(2) Controlled reduction: put the dry material dust obtained by pretreatment in a fine reduction device and pass in a reducing gas for reduction. The control parameters are:

1) Reduction temperature: 900 ~ 1050°C;

2) Gas reduction:

;

3) Reduction time: fixed bed 1~2h, moving bed 10~20min;

(3) Fine reduction: The solid residue produced by fine reduction is 50%~70% of the original material, and an appropriate amount of lime is added to make a desulfurizer for steelmaking and refining. The control parameters are:

1) Lime composition: CaO≥80%;

2) Quaternary alkalinity in the finished desulfurizer: 2~3;

3) In the finished desulfurizer: FeO≤1%;

Enrichment of high-zinc volatile products produced by fine reduction: the reduced zinc volatilizes and escapes in gaseous form at 900-1050°C, and is cooled and enriched by a dust collection device to obtain a high-purity zinc-rich product, which contains 10 %~15% KCl can be dissolved by washing with water.

2. a kind of zinc-containing blast furnace dedusting ash recycling treatment method as claimed in claim 1 is characterized in that reducing gas is blast furnace gas or hydrogen, and its reducing property is defined as , in order to ensure its strong reducibility, the blast furnace gas needs to be reformed, and the reforming parameters are:

1) Reforming agent: blue carbon or coke (fixed carbon ≥ 80%);

2) Reforming temperature: 950~1200℃.