CN1283814C - Method for producing iron ore by baking troilite powder in cyclone furnace - Google Patents

Abstract

A method for producing iron nugget ore by roasting pyrite powder in a cyclone furnace, comprising pyrite powder containing more than 90% of pyrite minerals, flux material containing CaO+MgO or SiO ₂ components and pyrite slag fine The powder is mixed according to the specified ratio to form a mixture, which is fed into the cyclone furnace for roasting, and the roasting flue gas containing SO ₂ is dedusted and purified to produce sulfuric acid. Required iron ore. The pyrite powder is roasted in a cyclone furnace, and the dust content of the flue gas is low, which is beneficial to the subsequent dust removal and purification process. During the roasting process, the temperature is high, the combustion speed is fast, and the sulfur removal rate is high. The sulfur content of the slag can be reduced to less than 0.2%, and the iron content is greater than 60%, which meets the quality requirements of ironmaking for iron nuggets. After the liquid slag is cooled and crushed, the iron ore can be obtained directly, which saves the sintering process of the fine ore, reduces the cost, and makes full and effective use of the iron resources in the pyrite ore.

Description

Method for producing iron nugget ore by roasting pyrite powder in cyclone furnace

1. Technical field: It belongs to the technical field of chemical industry and metallurgy.

2. Background technology: Fluidized-bed furnace roasting pyrite to produce sulfuric acid is a mature technology that has been used for hundreds of years, and is still widely used in the sulfuric acid production industry at home and abroad. Most of the pyrite ores used in fluidized fluidized furnaces are ordinary pyrite ores containing 30%-45% S, and the particle size is less than ^6mm . Contains 40%-55% iron. Due to the large dust content of the flue gas, the pressure of the subsequent dust removal work is high, the cost is high, the slag contains high sulfur and low iron content, and the comprehensive utilization of iron is difficult.

The pyrite is purified by the mineral processing method to obtain pyrite powder containing more than 90% of pyrite minerals and a particle size of less than 1mm. Although the slag containing more than 60% of iron and less than 0.5% of sulfur can be obtained by roasting in a fluidized bed furnace, When the slag is used as a raw material for ironmaking, its structure is loose and porous, its sintering strength is low, and its pulverization is serious, which is not conducive to blast furnace ironmaking, and the sulfur content of 0.5% is still relatively high. When the raw material particle size of the fluidized fluidized furnace is too fine, the dust content of the flue gas will be larger, which is not conducive to the subsequent dust removal treatment. Pyrite powder has high sulfur content, fine particle size, fast burning speed, high calorific value, difficult control of roasting temperature, and prone to sintering phenomenon, which affects the normal production. Therefore, for pyrite powder with high sulfur content and fine particle size, although boiling furnace roasting can be carried out, it is no longer a good method. According to the properties of pyrite powder, it is of great significance to develop a new roasting technology and method to improve roasting efficiency and make full use of iron and sulfur resources.

The cyclone furnace is a mature equipment that has been used for many years in the combustion of pulverized coal in thermal power plants. Due to its fast combustion speed, high combustion intensity, complete combustion, low dust content in flue gas, and liquid slag removal, it brings many benefits to operation and environmental control. Therefore, it has been widely used in thermal power industry. However, roasting pyrite with a cyclone furnace has not been applied so far. The main reason is that the pyrite used in industry has a low sulfur grade, which contains a large amount of gangue minerals with high hardness and high melting point such as quartz and alumina. Generally at -6mm, the particle size is coarse. When the cyclone furnace is used for combustion, the combustion is incomplete. The high-speed swirl movement causes serious wear on the inner wall of the cyclone furnace, and the cyclone furnace cannot work stably for a long time. For pyrite powder, there are no ore particles larger than 1mm, the content of -0.074mm and -0.045mm is high, the burning speed is fast, the calorific value is large, the melting point of slag is low, and the wear of the furnace wall is small during the swirl movement. Furnace combustion has become possible.

3. Summary of the invention: The purpose of this invention is to provide a method for producing low-dust SO ₂ for sulfuric acid production by roasting pyrite ore powder in a cyclone furnace, and at the same time using liquid slag to produce iron nugget ore. Through batching, mixing, roasting, and liquid slag cooling and solidification processes, iron nugget ore with low sulfur content, high iron content, alkalinity and particle size meeting ironmaking requirements is obtained.

The present invention is realized through the following technical solutions:

1. Ingredients

(1) Raw materials: pyrite powder + flux + slag return

The pyrite powder contains more than 90% by weight of pyrite minerals, the particle size of ore grains is less than 1mm, and the weight percentage of water is not more than 16%.

The flux is a mineral containing SiO ₂ or CaO+MgO, and the particle size is less than 1mm.

The returned slag is the combination of -5mm fine particle slag sieved from the pyrite slag crushing product and re-crushed to less than 1mm, and the slag dust discharged from the dust removal device.

(2) Ratio of ingredients

Pyrite powder: flux: slag return = 100: A (or B): C (or C ₁ ) where:

A＝100(RB ₁ -A ₁ )/A ₂ (1)

B=100[(A ₁ /R)-B ₁ ]/B ₂ (2)

C＝0～3.33S-A-100 (3)

C ₁ =0～3.33SB-100 (4)

In the formula: the alkalinity required by R-iron nugget ore, R=(CaO+MgO)/SiO ₂ =0.7-1.5;

The mineral weight containing CaO+MgO that needs to be added in A-100 kilograms of pyrite powders;

A ₁ —the weight percentage of CaO+MgO in the pyrite powder;

A ₂ —the weight percentage of CaO+MgO in the flux mineral that adds;

Need to add _SiO in B-100 kilograms of pyrite powders Mineral weight;

B ₁ — _SiO in the pyrite powder The weight percentage;

B ₂ — SiO in the flux mineral added ₂ % by weight;

When C—adding flux is CaO+MgO, the weight of the slag that adds in 100 kilograms of pyrite powders;

C ₁ —adding flux is SiO ₂ when, the weight of the returning slag that adds in 100 kilograms of pyrite powders;

S—the sulfur grade of pyrite powder.

Based on the specific alkalinity R required by iron nugget ore, by R=(CaO+MgO)/ _SiO Calculation, when the weight percentage of CaO+MgO in the pyrite powder is insufficient, use (1), (3 ) formula to calculate the amount of CaO+MgO that needs to be added; when the weight percentage of _SiO in pyrite powder is insufficient, use (2) and (4) to calculate the amount of _SiO that needs to be added.

(3) Mixing

Return slag, mineral flux containing SiO ₂ or CaO+MgO, and pyrite powder with water content not greater than 16% are stirred and mixed evenly in a mixer according to the above-mentioned proportion of ingredients. The moisture content and sulfur content grade of the mixture are:

${\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 100</span>}\mathrm{<span\; class="notranslate">\; E.</span>}}{\mathrm{<span\; class="notranslate">\; 10000</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 100</span>}\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 100</span>}\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; EA</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; EC</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 100</span>}<span\; class="notranslate">\; \%</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

${\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 100</span>}\mathrm{<span\; class="notranslate">\; E.</span>}}{\mathrm{<span\; class="notranslate">\; 10000</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 100</span>}\mathrm{<span\; class="notranslate">\; B</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 100</span>}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; EB</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; EC</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 100</span>}<span\; class="notranslate">\; \%</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; )</span>$

${\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; S</span>}}{\mathrm{<span\; class="notranslate">\; 100</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; C</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 100</span>}<span\; class="notranslate">\; \%</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; )</span>$

${\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; S</span>}}{\mathrm{<span\; class="notranslate">\; 100</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; B</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 100</span>}<span\; class="notranslate">\; \%</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 8</span>}<span\; class="notranslate">\; )</span>$

In the formula: E—weight percentage of pyrite powder moisture;

E ₁ - the weight percentage of the moisture content of the mixture;

S ₁ —the sulfur grade of the mixture.

When the added flux is CaO+MgO, use formulas (5) and (7) to calculate the weight percentage and sulfur content of the mixture, and the added flux is SiO ₂ , use formulas (6) and (8) to calculate the moisture content of the mixture The weight percentage and sulfur grade.

2. Cyclone furnace roasting

(1) Cyclone furnace design parameters

The cyclone furnace for roasting pyrite mixed ingredients is installed with an inclination angle of 0-90°, and the ratio of the length to diameter of the cyclone is L/D=4-6, which is determined through experiments according to the particle size and sulfur grade of pyrite to ensure The slag contains no more than 0.2% sulfur.

(2) Cyclone furnace roasting process and control process conditions

Roasting of the mixed material after batching of pyrite powder is carried out in a water-cooled cyclone. The preheated air at 300-450°C is fed tangentially into the cyclone at a speed of 40-150m/s, forming a swirl along the inner wall of the cyclone, and the pyrite powder mixture is fed into the cyclone tangentially, axially or tangentially In the cylinder, it rotates under the drive of the rotating air flow, and burns at a temperature of 1200-1450°C at the same time. The excess air coefficient is 1.1-1.2. The air volume accounts for 80-90% of the volume percentage of the total air volume. The combustion reaction is: (when pyrite is pyrite), (When the pyrrhotite is pyrrhotite), the burning slag is in a molten liquid state and moves in a spiral along the cylinder wall under the action of rotating centrifugal force. During the movement, the pyrite particles that have not been completely burned continue to burn until Liquid slag is discharged from the slag outlet, cooled and solidified to obtain iron ore. The _SO2 -containing gas generated by the combustion reaction is roasting flue gas, and the fine-grained slag in the flue gas is partially trapped into the liquid slag pool after encountering the slag trap, and is discharged from the slag outlet along with the liquid slag. After passing through the slag collecting pipe, the dust content of the flue gas is less than 60g/m ³ , and the SO ₂ flue gas with a dust content of less than 10 mg/m ³ after dust removal and purification enters the sulfuric acid system to produce sulfuric acid.

The cooling and solidification of liquid slag can be done in the following three ways:

1) When the liquid slag flows out from the slag outlet, it is blown with the air of natural temperature generated by the fan, so that the particle size of the slag after cooling and solidification is less than 40mm. The solidified slag is screened, the fine slag smaller than 5mm is used as the return slag, and the massive slag of 5-40mm is the qualified iron ore.

2) After the liquid slag flows out from the slag outlet, it is naturally cooled and solidified, and then crushed into -40mm by a crusher, and the -5mm fine-grained slag is sieved as the returned slag, and the lumpy slag of 5-40mm on the sieve is a qualified iron block mine.

3) The liquid slag flows directly into the water tank, and forms granulated water-quenched slag under the rapid cooling of water at 0-100°C. This slag can be used as a raw material for direct reduction ironmaking.

The fine-grained ash discharged from the dust removal system is returned to the batching system for batching as returning slag.

The present invention has the following advantages:

1. The present invention has simultaneously completed the roasting task of producing acid from pyrite, the desulfurization task of producing iron ore from pyrite and the sintering task of iron fine ore;

2. When the pyrite powder is burned in the cyclone furnace, the combustion temperature is high, the burning rate of sulfur is high, and the sulfur content of the slag can be as low as 0.2%, which meets the requirements for the sulfur content of ironmaking raw materials;

3. Pyrite powder is burned in the cyclone furnace, and the slag is liquid slag. After cooling and solidification, iron nugget ore with particle size meeting the requirements of ironmaking can be obtained, which saves the sintering process of fine-grained slag;

4. Controlling the impurity content of pyrite powder can make the iron grade of cinder iron lump ore more than 60%, which can meet the needs of blast furnace ironmaking;

5. Through the batching treatment of pyrite powder, iron nuggets and neutral (self-fluxing) iron nuggets with different pH can be obtained according to ironmaking needs;

6. The dust content of the flue gas is much smaller than that of the fluidized furnace flue gas, which reduces the pressure and cost of the subsequent flue gas dust removal. Liquid slag discharge also reduces environmental pollution caused by dust.

Fourth, the specific implementation method:

Embodiment one:

1. Ingredients

(1) Raw materials

Pyrite powder + flux + slag return

Pyrite powder contains pyrite minerals as pyrite, pyrite mineral content is 96%, sulfur grade S=51.26%, SiO ₂ weight percentage is B ₁ =1.2%, the weight of CaO+MgO The percentage content is A ₁ =0.5%, the ore particle size is -0.074mm90%, and the water content E=12%.

The flux is CaO, and the particle size is less than 1mm.

The returned slag is the combination of -5mm fine particle slag sieved from the pyrite slag crushing product and re-crushed to less than 1mm, and the slag dust discharged from the dust removal device.

(2) Ratio of ingredients

The basicity R=1 required by iron nugget ore.

Pyrite powder: CaO: return slag = 100: A: C = 100: 0.7: 25

(3) Mixing

Return slag, CaO, and pyrite powder are stirred and mixed evenly in a screw mixer according to the above-mentioned proportion of ingredients. The water content of the mixture E ₁ =9.79%, and the total sulfur grade S ₁ of the mixture is 40.78%.

2. Cyclone furnace roasting

(1) Cyclone furnace design parameters

The cyclone furnace for roasting pyrite mixed ingredients, with an inclination angle of 90°, is a vertical cyclone furnace. The ratio of the length to the diameter of the cyclone is L/D=5.

(2) Technological conditions of cyclone furnace roasting control

The preheated air at 300-400°C is tangentially fed into the cyclone at a speed of 90-120m/s, the combustion temperature of the pyrite mixture is 1300-1450°C, the excess air coefficient is 1.2, and the primary air volume of the cyclone accounts for 10% of the total air volume. The volume percentage is 15%, and the volume percentage of the secondary air volume of the cyclone is 85% of the total air volume. The liquid slag is discharged from the slag outlet, and blown by the natural temperature air generated by the fan, so that the particle size of the slag after cooling and solidification is less than 40mm. The solidified slag is screened, and the fine-grained slag smaller than 5mm is used as the returning slag, and the massive slag of 5-40mm is the iron ore with an alkalinity of 1 and qualified self-fluxing. The fine-grained ash discharged from the dust removal system is returned to the batching system for batching as returning slag.

3. The main technical indicators obtained: the iron ore contains 65.53% Fe and 0.15% S, the SO ₂ in the flue gas entering the acid system meets the acid standard, and the dust content is less than 10mg/m ³ .

Embodiment two:

1. Ingredients

(1) Raw material

Pyrite powder + flux + slag return

Pyrhotite powder contains pyrrhotite minerals, pyrrhotite mineral content is 95%, sulfur grade S=37.53%, SiO ₂ weight percentage is B ₁ =1.2%, CaO+MgO The weight percent content is A ₁ =1.0%, the ore particle size is -0.074mm95%, and the water content E=11%.

The flux is limestone + dolomite, the weight percentage of CaO + MgO is A ₂ =44%, and the particle size is less than 1mm.

Return slag is the slag dust removed from the dust removal device.

(2) Ratio of ingredients

The basicity R=1.1 required for iron ore.

Pyrite powder: limestone + dolomite: return slag = 100: A: C = 100: 0.73: 24

(3) Mixing

Return slag, limestone + dolomite, and pyrite powder are stirred and mixed evenly in a spiral mixer according to the above-mentioned proportion of ingredients. The water content of the mixture E ₁ =9.02%, and the total sulfur grade S ₁ of the mixture is 30.09%.

2. Cyclone furnace roasting

(1) Cyclone furnace design parameters

The cyclone furnace for roasting pyrite mixed ingredients, with an inclination angle of 0°, is a horizontal cyclone furnace. The ratio of the length to the diameter of the cyclone is L/D=4.

(2) Technological conditions of cyclone furnace roasting control

The preheated air at 350-450°C is tangentially fed into the cyclone at a speed of 100-150m/s, the combustion temperature of the pyrite mixture is 1200-1300°C, the excess air coefficient is 1.1, and the primary air volume of the cyclone accounts for 10% of the total air volume. The volume percentage is 20%, and the secondary air volume of the cyclone accounts for 80% of the total air volume. The liquid slag is discharged from the slag outlet, directly flows into the water tank, and forms granulated iron ore under the rapid cooling of water at 0-100°C.

The fine-grained ash discharged from the dust removal system is returned to the batching system for batching as returning slag.

3. The main technical and economic indicators obtained: the granulated iron ore contains 66.21% Fe and 0.2% S, the SO ₂ in the flue gas entering the acid system meets the acid standard, and the dust content is less than 10mg/m ³ .

Embodiment three:

1. Ingredients

(1) Raw material

Pyrite powder + flux + slag return

The pyrite powder contains pyrite minerals pyrite and pyrrhotite, the pyrite mineral content is 90%, the sulfur grade S=44%, the weight percentage of _SiO2 is _B1 =1.5%, CaO The weight percentage of +MgO is A ₁ =1.2%, the ore particle size is less than 1mm, the content of -0.074mm is 50%, and the water content E=16%.

The flux is clay mineral containing SiO ₂ with a particle size of less than 1mm.

The returned slag is the combination of -5mm fine particle slag sieved from the pyrite slag crushing product and re-crushed to less than 1mm, and the slag dust discharged from the dust removal device.

(2) Ratio of ingredients

The required alkalinity R=0.8 for iron ore.

Pyrite powder: clay ore: return slag = 100: B: C = 100: 0: 30

(3) Mixing

The returned slag and the pyrite powder are stirred and mixed evenly in a screw mixer according to the above-mentioned proportion of ingredients. The water content of the mixture E ₁ =12.78%, and the total sulfur grade S ₁ of the mixture is 33.85%.

2. Cyclone furnace roasting

(1) Cyclone furnace design parameters

The cyclone furnace for roasting pyrite mixed ingredients, with an inclination angle of 20°, is a horizontal cyclone furnace. The ratio of the length to the diameter of the cyclone is L/D=6.

(2) Technological conditions of cyclone furnace roasting control

The preheated air at 350-400°C is tangentially fed into the cyclone at a speed of 40-100m/s, the combustion temperature of the pyrite mixture is 1250-1350°C, the excess air coefficient is 1.15, and the primary air volume of the cyclone accounts for 10% of the total air volume. The volume percentage is 10%, and the volume percentage of the secondary air volume of the cyclone is 90% of the total air volume. The liquid slag is discharged from the slag outlet, cooled and solidified naturally, and then crushed into -40mm by a crusher, and the -5mm fine-grained slag is sieved as the returned slag, and the blocky slag of 5-40mm on the sieve is qualified with an alkalinity of 0.8 Iron ore.

The fine-grained ash discharged from the dust removal system is returned to the batching system for batching as returning slag.

3. The main technical and economic indicators obtained: the iron ore contains 61.40% Fe and 0.2% S, the SO ₂ in the flue gas entering the acid system meets the acid standard, and the dust content is less than 10mg/m ³ .

Claims (6)

1, a kind of method of producing iron ore by baking troilite powder in cyclone furnace is characterized in that, raw material is troilite powder+flux+return slag.

2, the method for producing iron ore by baking troilite powder in cyclone furnace according to claim 1 is characterized in that, described troilite powder contains the weight percentage of sulfurous iron ore mineral greater than 90%, and granularity is less than 1mm, and the weight percentage of moisture is not more than 16%; Described flux is CaO+MgO or SiO ₂, basicity R=(CaO+MgO)/SiO that its add-on requires according to iron ore ₂=0.7～1.5 are determined; Described return slag sifts out from the pyrite cinder product-and the particulate of 5mm burns slag and is crushed to-1mm again, merges with the burning slag dust of discharging in the cleaning apparatus to form.

3, according to the method for each described producing iron ore by baking troilite powder in cyclone furnace in the claim 1～2, it is characterized in that when the weight percentage of CaO+MgO in the troilite powder was not enough, proportioning raw materials was, troilite powder: flux: return slag=100: A: C, (the R B of A=100 in the formula ₁-A ₁)/A ₂, be to need the mineral weight that contains CaO+MgO that adds in the double centner troilite powder, C=0～3.33S-A-100 is to need the return slag weight that adds in the double centner troilite powder, B ₁Be SiO in the troilite powder ₂Weight percentage, A ₁Be the weight percentage of CaO+MgO in the troilite powder, A ₂Be the weight percentage of CaO+MgO in the fluxing mineral that adds, S is the sulfur-bearing grade of troilite powder; SiO in troilite powder ₂Contain quantity not sufficient the time, proportioning raw materials is troilite powder: flux: return slag=100: B: C ₁, B=100[(A in the formula ₁/ R)-B ₁]/B ₂, be to need the SiO that contains that adds in the double centner troilite powder ₂The weight of mineral, C ₁=0～3.33S-B-100 is the weight that needs the return slag that adds in the double centner troilite powder, B ₂Be SiO in the fluxing mineral that adds ₂Weight percentage.

4, a kind of method of producing iron ore by baking troilite powder in cyclone furnace, it is characterized in that, design variable in order to the cyclone furnace of each preparation raw material in the roasting claim 1 to 3 is that the mounting inclination angle degree is 0-90 °, the ratio L/D=4-6 of the length of whirlwind tube and diameter; The technical matters condition of control is, air preheating temperature 300-450 ℃, flow velocity 40-150m/s, 1200-1450 ℃ of stove internal combustion temperature, excess air ratio 1.1-1.2, whirlwind tube primary air flow accounts for the percent by volume 10-20% of total blast volume, and whirlwind tube secondary air flow accounts for the percent by volume 80-90% of total blast volume, the liquid slag cooling curing of output obtains iron ore, contains SO ₂Dust contained flue gas less than 10mg/m ³

5, the method for producing iron ore by baking troilite powder in cyclone furnace according to claim 4 is characterized in that, the compound of described troilite powder feed in the whirlwind tube direction for tangential axially or cut to.

6, the method for producing iron ore by baking troilite powder in cyclone furnace according to claim 4, it is characterized in that, described liquid slag treatment process is: when (1) liquid slag flows out from slag notch, the air blown of the natural temperature that produces with blower fan, make granularity behind the liquid slag cooling curing less than 40mm, sieving solidify burning slag, burning slag as return slag less than the particulate of 5mm, it is exactly qualified iron ore that the bulk of 5-40mm is burnt slag; (2) after liquid slag flowed out from slag notch, naturally cooling solidified, again with crusher in crushing one-tenth-40mm, sift out-5mm particulate burning slag is as return slag, and the bulk of 5-40mm burning slag is exactly qualified iron ore on the sieve; (3) liquid slag directly flows to water tank, forms the granulation iron ore under the chilling effect of 0～100 ℃ of water.