CN1766131A

CN1766131A - Method for producing direct-reduced iron and pig iron

Info

Publication number: CN1766131A
Application number: CN 200510123467
Authority: CN
Inventors: 方兴; 马再男
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-11-21
Filing date: 2005-11-21
Publication date: 2006-05-03

Abstract

The invention discloses a new method to produce DRI and pure pig-iron, which comprises: extruding the iron concentrate powder, solid carbon-contain material powder and desulfurizer to form shell structure with adhesive; forming fire-resistant shell with thickness than 1.0mm by fire resistive material; drying, heating in grate; finally, removing the fire-resistant shell. This invention needs no coke and low cost, and reduces pollution. Wherein, the coal or gas can reduce and produce qualified DRI and pure pig-iron on high oxidizing environment.

Description

A kind of method of producing the direct-reduced iron and the pig iron

Technical field

The present invention relates to a kind of smelting process, relate in particular to a kind of method of producing the direct-reduced iron and the pig iron, belong to field of metallurgy.

Background technology

In recent years, China's Iron And Steel Industry has obtained develop rapidly, become the first in the world and produce steel big country, but the structure of China's steel products is still waiting to adjust, the quality of steel products is still waiting to improve, high-quality Clean Steel and high-quality steel also can not satisfy needs of economic development far away, the sustainable development of Iron And Steel Industry, suffer from many difficulties, blast furnace ironmaking raw material, fuel, iron ore, coking coal and coke supply anxiety, price rises steadily, cause the quality raising of crude fuel to be restricted, production cost goes up, steel scrap shortage, the especially shortage of high-quality steel scrap, the decline of Iron and Steel Production energy consumption and the development of high-quality steel have been limited, still than the high 30%-40% of advanced international standard, Iron and Steel Production still is not controlled effectively to the pollution of environment the crude steel energy consumption, mainly shows: the CO of the high unit product discharging of energy consumption ₂Amount is big, a series of problems such as waste water, exhaust gas emission total amount increase considerably are improved the energy consumption structure of Iron And Steel Industry, break away from the dependence of Iron and Steel Production to coking coal, cut down the consumption of energy and reduce and eliminate detrimentally affect, become Iron and Steel Production and realize one of critical limitation link of Sustainable development environment.Seeking new is the Steel Production Flow Chart of the energy with the noncoking coal, becomes the problem that people pay close attention to.In this case, people seek new smelting process, carry out one after another direct reduction and melting and reducing technology and research and development.

Directly reduction is varied with fusion technology at present, divides by the reductive agent kind, is divided into two kinds of gas base directly reducing and coal-based direct reductions; Kind by reduction reactor is divided, and is divided into gas-based shaft kiln method, gas base fixed bed process, gas base fluidized bed process and coal-based rotary kiln method, coal-based fixed bed process (tunnel furnace method or pot type method), coal-based shaft furnace process, rotary hearth furnace method etc.

The energy of gas-based shaft kiln method, gas base fixed bed process, gas base pot type method, gas base fluidized bed process is Sweet natural gas or high heating value gases such as coke-oven gas or gas maked coal, and these technologies must be used expensive fuel.

Though the fuel that kiln process uses is the hyperergy noncoking coal, price is cheaper than gas base, and the reductive pelletizing needs secluding air, prevents to reoxidize, and just can obtain direct-reduced iron, complex process.The production of the kiln process of cold bound pellet is loaded down with trivial details in addition, need make cold bound pellet earlier and enter the reduction of Da rotary kiln again, because the abrasive wear resistance problem of cold bound pellet, production is difficult to stablize, and initial cost is bigger, the total energy consumption height.Coal-based fixed bed process (tunnel furnace method or pot type method) is the most ancient direct-reduction process, the problem that its exists is: energy consumption height, seriously polluted, unstable product quality, investment be big, yield poorly and consume a large amount of reduction jars aborning, investment and cost are increased significantly, and present rotary hearth furnace method yields poorly.In addition, when traditional blast-furnace smelting exists oxide compound to be reduced to iron, there are the silicon of a great deal of, the oxide compound of manganese to be reduced, and enter in the pig iron with a large amount of carbon, steel-making is carried out oxidation refining to molten iron, remove these impurity on the one hand, have to again removing superfluous oxygen, cause the additive decrementation of energy and raw material, blast furnace ironmaking must use coke besides, and the coking coal resource of producing coke only accounts for 5% of coal total reserves, and the coking coal resource shortage is in short supply.In addition, coking production is very big to the pollution of environment.

The production of traditional ironmaking is the ironmaking flow process of big coke oven-big sinter machine-big blast furnace, also exposed simultaneously a series of problem: the initial cost expense is big, sintering and big, serious, the worldwide coking coal shortage of environmental pollution of coke making process investment, costs an arm and a leg.

Summary of the invention

Technical problem to be solved by this invention is to overcome the deficiencies in the prior art, and a kind of new production reduced iron and the method for the pure pig iron are provided, and this production method does not need coke, has advantages such as technology is simple and direct, production cost is low, reduction environmental pollution.

Technical problem to be solved by this invention realizes by following technological approaches:

A kind of method of producing the direct-reduced iron and the pure pig iron, may further comprise the steps: fine iron breeze, solid carbon raw material powder and the extruding of sweetening agent adding additives are formed shell structure, the skin of shell structure is wrapped to form the fire-resistant shell of thickness greater than 1.0mm with refractory materials, dry laggard people's stove heating, remove fire-resistant shell at last, promptly get the direct-reduced iron or the pure pig iron.

In the aforesaid method, the shape of described shell structure can be selected arbitrarily according to the production practical situation, and this for example can be preferably ball-type or square for ball-type, square, cylinder shape, rib type etc. all without prejudice to essence of the present invention;

Described refractory materials can be the mixture that a kind of arbitrarily refractory materials or more than one refractory materials are formed with arbitrary proportion.For example, clay matter, high alumina matter, aluminum oxide, siliceous or magnesia refractory materials can be selected for use, also magnalium matter or lime refractory can be selected for use, or with magnesium-aluminium spinel, the aluminous cement fire-resistant shell as outsourcing.Be preferably aluminum oxide refractory materials, siliceous and fireclay or aluminous cement.

The number of plies of described shell structure can be one or more layers, and the number of plies of this shell structure can be determined according to the practical situation or the demand of producing.For example, can with high-grade fine iron breeze with form one deck shell structure after solid carbon raw material powder and sweetening agent mix and add binding agent; Perhaps with fine iron breeze directly with binding agent extrusion formation sandwich layer, through cryodrying, outside surface superscribes the pulverulent mixture that one deck is made up of solid carbon raw material powder, binding agent and sweetening agent again, making sandwich layer is piece or the globe that fine ore is pressed, and the sandwich layer skin is enclosed with two layers of shell structure of solid carbon raw material powder, binding agent and sweetening agent.Adopt which kind of raw material to prepare as for each shell, the weight proportion between the various raw materials, this practical situation or demand of also looking production is determined, is that those skilled in the art knows, and all should be included within the scope of the invention.

The inventive method has the major advantage of following several respects: (1) production technique is simple, and cost is low, less investment.(2) energy consumption is low, can briquet replacing coke, and the output height, energy-efficient.(3) effectively reduce pollution to surrounding environment.(4) adaptability is strong: whatsoever the form stove all is suitable for.The inventive method and existing iron-smelting process relatively can be saved a large amount of cokes, reduce and pollute, and direct production goes out the steel-making pig iron, and the coal of heating usefulness or coal gas can reduce in higher oxidative environment produces the qualified direct-reduced iron and the pure pig iron.Produce direct-reduced iron relatively with tunnel furnace in addition, can cut down the consumption of energy to have save and consume higher reduction jar, alleviated heavy manual work, and the refractory materials under peeling off after the reduction can powder essence repeatedly use, and relatively can increase substantially output with rotary hearth furnace and shaft furnace, rotary kiln.

Further describe beneficial effect of the present invention by the following examples, it should be understood that these embodiment only are used for the purpose of illustration, never limit protection scope of the present invention.

Embodiment

[embodiment 1]

Choose the iron ore concentrate 10kg (water content 11% of grade 68.61%, control concentrate moisture content is 7% one 8%), add 0.18kg carboxymethyl cellulose (CMC) through totally 373 of roller ball pressuring machine pressure balls, spherical diameter 20mm, the on average heavy 26g of each ball is dried, the heavy 24.2g of the average ball in oven dry back, moisture below 1.0%, the dry bulb dropping strength is 4 times/.

Drop into then in the hard coal and the mixed solid fuel powder of fixed carbon content＞60% bituminous coal with fixed carbon content＞80%, in the solid fuel powder, add Wingdale, Wingdale contains CaO＞50%, (hard coal and bituminous coal proportioning are 7: 3, granularity＜1.0mm) is made ball, makes ball making the solution that ball sprays into CMC simultaneously, on average reaches 2.6mm when thick when sphere is stained with coal dust, stop to make ball, take out dry 0.5h in 200-280 ℃ hot blast.Ultimate compression strength reaches 11N/.

To superscribe solid-fuelled spherical body at last, and send into again in the balling disk (-sc), and superscribe siliceous outside and fireclay, and the solution that sprays into CMC is simultaneously made ball.When the outsourcing refractory thickness on average reaches 3mm, stop to make ball, in about 100 ℃ hot blast, dry 0.5h.

20 of this batch spherical bodies are put in the retort furnace that is warmed up to 1150 ℃, behind the roasting 30min, naturally cool to the room temperature pulverizing and remove outer refractory.The assay such as the table 1 of products obtained therefrom:

Table 1 assay: (unit: Wt%)

T _Fe 92.01

M _Fe 89.41

Degree of metalization 97.17

S 0.017

P 0.02

C 0.014

Presentation of results, the prepared product of present embodiment conforms to quality requirements fully.

[embodiment 2]

Ball making method is with example 1

Get 20 and account for α-Al of 85% with granularity＜0.005mm ₂O ₃Content is put the ZrO that the people has been warmed up to 1500 ℃ ± 20 ℃ greater than the globe that 99% commercial alumina powder wraps up ₂In the electric furnace, burn till 20min after, take out naturally cooling, the ground-slag that outer fire-resistant shell and appearance are hung is fallen in fragmentation.The assay such as the table 2 of products obtained therefrom:

Table 2

Interventions Requested result (unit: Wt%)

Fe 97.21

S 0.014

P 0.016

C 0.019

[embodiment 3]

Get the same fine iron breeze 10kg and 3.5kg pulverized anthracite mixing briquetting physical dimension 50 * 50 * 20mm that handles of EXAMPLE l, superscribe aluminous cement outside with embodiment 1 is the same after, drying.Put into 1250 ℃ retort furnace roasting 20min, take out air-cooledly, pulverize shell to room temperature.The assay such as the table 3 of products obtained therefrom:

Table 3

Interventions Requested result (Wt% of unit)

T _Fe 91.79

M _Fe 88.30

Degree of metalization 96.20

S 0.143

P 0.064

C 0.039

Claims

1. method of producing the direct-reduced iron and the pure pig iron, may further comprise the steps: fine iron breeze, solid carbon raw material powder and sweetening agent adding additives are formed shell structure, the skin of shell structure is wrapped to form the fire-resistant shell of thickness greater than 1.0mm with refractory materials, dry laggard people's stove heating, remove fire-resistant shell at last, promptly get the direct-reduced iron or the pure pig iron.

2. according to the method for claim 1, it is characterized in that: the mixture that described refractory materials is formed for a kind of refractory materials arbitrarily or more than one refractory materials.

3. according to the method for claim 2, it is characterized in that: described refractory materials is selected from aluminum oxide refractory materials, siliceous and fireclay or aluminous cement.

4. according to the method for claim 1, it is characterized in that: the number of plies of described shell structure is one or more layers.

5. a direct-reduced iron or the pure pig iron is characterized in that any product that method prepares by claim 1-4.