What does blast furnace have with fireproof material?

Blast furnace lining uses the use condition of fireproof material

Blast furnace uses fireproof data, must maintain the stability on physics and chemistry to the reaction inside furnace, should achieve the following requirement:

(1) fall in high temperature, not fused, not bate, do not volatilize;

(2) should have the strength with whole structure of body of heater can retain below condition of high temperature, high pressure;

(3) heat-resisting concussion, wear-resisting caustic;

(4) have pair of molten iron, slag and stove inside gas the chemical stability that wait;

(5) have appropriate heat conduction rate, do not affect cooling result again at the same time.

 

Area	Move relatively	Heat up exchange	Reaction
Solid photograph area (lump is taken)	Solid charging drops gas rise	Rise gas undertake heating mixing to solid charging dry	Indirect and reductive, aerification reacts, solution of carbonic acid salinity, part is direct and reductive
Area of soft be in harmony (soft be in harmony is taken)	Gas pass coke interlining	Layer of ore bate, half frit, gas half-and-half frit undertakes conducting heat	Direct and reductive, cementite
Drippy area (distill belt)	Solid coke drops, to coke of whirly area supply, frit iron is mean	Those who rise is gas have trade with distilled dissolve broken bits, molten iron and coke	Alloying element is direct and reductive, to decoke, cementite, reductive
Whirly area (combustion is taken)	Blast makes coke circumnutation	Coke combustion is radiative, generation high temperature is gas	Combustion reaction, part oxidizes again
Crucible area (broken bits metal strip)	Of molten iron and dissolve broken bits store	The heat exchange of iron of the heat radiation of upside, broken bits and coke	The reductive, to decoke between iron of final fine, broken bits, cementite

Each place uses blast furnace lining fireproof material

Modern big, medium-sized blast furnace asks generation furnace life is 10 years (even 15 years) . Stand or fall of the breed of fireproof material, quality affects blast furnace life directly. Because this is opposite,the breed of fireproof material, quality raised very strict requirement.

See in the graph, erode the most serious place to be bosh, belly and shaft lower liner.

According to blast furnace status of the reaction condition of each area, job, temperature, thermal shock, after eroding the research that wait, make corresponding change character to material when the choice uses fireproof data.

Shaft upside and mid with fireproof material

 In shaft upside, because cloth and charging drop,its damaged mechanism basically is the chemistry that brought machine erodes and the along with ascendant air current alkali metal place that collects here produces is eroded.

   In shaft mid, basically be thermal shock is destroyed, it is machinery erodes next.

Shaft upside and mid erode a reason to reach to be able to bear or endure the basic function of material asks:

Erode a reason	To the performance demand of fireproof material
1. charging drops of the process wear away Of air current of 2. ascendant coal erode wear away 3. alkali metal is eroded destroy The destruction of 4.CO action	1. compression intensity is high It is good that 2. fights alkali metal aggressivity 3. porosity is low Content of 4. ferric oxide is low

Choose fireproof material: Brick of argillaceous brick, silicon line stone, compact clay brick, tall aluminous brick.

 Blast furnace shaft used advanced clay brick, tall aluminous brick, Molaishi all the time in the past brick of stone of line of brick, corundum brick, silicon, carbon brick, black lead brick and brick of half black lead, but begin to use carborundum brick from 70 time, till 1990, the blast furnace that there already were 65 ％ on the world used carborundum brick, in the large blast furnace that is more than 12m in crucible diameter, the blast furnace that has 68 ％ used carborundum brick.

According to combinative means, carborundum brick is β respectively - the carborundum brick of SiC union, Si3N4 union, Sialon union and Sialon- Si3N4 union. 70 time evening and 80 time initial stage, main use β - the carborundum brick that SiC combines, in 80 time evening, except Japan, the carborundum brick dosage of Si3N4 union, Sialon union and Sialon- Si3N4 union already occupied 67.5 ％ . Since 1986, world each country already had 10 several blast furnace to use the carbonization silica brick that Sialon- Si3N4 combines.

 Because carborundum brick has sex of caustic of intensity of good thermal conductivity, high temperature, wear-resisting, fight alkalescent and fight chemical aggressivity to wait, because this includes the blast furnace of the country such as Japan, United States, Germany, England,used carborundum brick to obtain very good use result. For example, life of American blast furnace raises 8 ～ 4 years 10 years from original 3 ～ , furnace life of Japanese large blast furnace raises 10 ～ 6 years 15 years by the 5 ～ in the past above.

Shaft bottom, belly

 Arrive from shaft bottom the bricky line of belly, suffer already drop charging and high pressure of ascendant high temperature wear away gasly and the thermal shock that temperature change causes, suffer tall FeO again the chemistry of the broken bits at the beginning of tall alkalinity is eroded, more serious is alkali metal and zincic steam (zinc passes oxide or sulfide enters blast furnace) the carbolic element deposit that cause and chemical reaction, make firebrick organization fragile change, lose strength.

Shaft bottom, belly erodes a reason to reach to be able to bear or endure the basic function of material asks:

Erode a reason	To the performance demand of fireproof material
The chemistry that broken bits becomes at the beginning of 1. is eroded 2. drops of charging wear away Of 3. metal iron erode destroy 4. coal air current erodes wear away 5. thermal shock causes flake	It is good that 1. fights broken bits aggressivity It is good that 2. fights alkali metal aggressivity Intensity of 3. high temperature is high 4. thermal conductivity is good 5. porosity is low Stability of 6. thermal shock is good

Choose fireproof material: Brick of aluminous charcoal brick, carborundum brick, hot pressing is small charcoal and half graphitization charcoal - carborundum brick.

Bosh uses fireproof data

Furnace bellyband erodes a reason to reach to be able to bear or endure the basic function of material asks:

Erode a reason	To the performance demand of fireproof material
Of air current of coal of 1. high temperature erode wear away Of iron of broken bits of 2. hot condition erode erode 3. high temperature destroys effect	Wearability of 1. high temperature is good It is good that 2. fights aggressivity of broken bits iron 3. thermal conductivity is good

Bosh is in bricklaying to be below the cooling action of cooling wall, can form broken bits skin, have protective effect.

Choose fireproof material: Tall aluminous brick, aluminous carbon brick, half graphitization carbon - brick of Si3N4 of union of brick of carborundum brick, hot pressing is small carbon, SiC.

Blast tuyere area uses fireproof data

 Blast tuyere area is the area with the highest temperature in blast furnace, as a result of blast furnace large turn the application with aggrandizement smelt technology, the sirocco kinetic energy that causes coping of mouth of sirocco of large blast furnace is very high; What the combustion area before blast tuyere is in air current and coke is intense disturb in, accordingly, lining gets high temperature air stream not only erode, and the abrasion that still gets blazing coke and dust, and contain FeO very tall the chemistry of broken bits is eroded first. Additionally contemporary gush blew coal fines operation to also increase the enroach on of fireproof to line of brick of blast tuyere area material undoubtedly.

Blast tuyere area erodes a reason to reach to be able to bear or endure the basic function of material asks:

Erode a reason	To the performance demand of fireproof material
Of iron of broken bits of 1. liquid state erode erode Of 2. alkali metal erode destroy Of 3. coal air current erode wear away 4. oxidation destroys effect	It is good that 1. fights aggressivity of broken bits iron It is good that 2. fights alkali metal aggressivity 3. fights O 2 , H 2O oxidisability is good 4. thermal conductivity is good

Blast tuyere area is fireproof material:

 Area of blast furnace a place with a draught uses brick of stone of line of argillaceous brick, tall aluminous brick, silicon to wait previously. In recent years, great opportunity is used generally to press carbolic piece build by laying bricks or stones to build in the blast tuyere belt of big, medium-sized blast furnace, the fan form and structure that build by laying bricks or stones builds semmetry all round blast tuyere. But be out of shape considering what cause as a result of basic material action, fight in order to convert alkalescent better carborundum brick, be like β - SiC union, Si3N4 union and brick of Sialon union SiC.

 Small-sized blast furnace uses tamp of charcoal element makings or charcoal more now piece bricky build by laying bricks or stones is built. Line of this part brick becomes whole with the bricky line build by laying bricks or stones of crucible, erode to prevent what oxidize all round blast tuyere, so that prevent drying-out and the combustion that the carbon in process opening furnace expects,the step that needs to use tall aluminous brick, clay brick or fireproof concrete builds covering layer.

Iron opening position uses fireproof data

 Iron opening position should bear with fireproof material of molten iron and slag erode and erode, and leaving, the outside force effect that mouth machine and slimy artillery piece get when the mouth that block iron up. Because position of this iron opening uses fireproof material to ask to fight aggressivity of slag, molten iron the ability that fights mechanical stress is good, good, at the same time build by laying bricks or stones is built want to stabilize on the structure. Use brick of chunk different combination, the brick when build by laying bricks or stones is built seams fluctuation to stagger, every monomer is mutual and occlusive, the pressure that makes come from furnace inside and outside to all around deliver, make body of whole build by laying bricks or stones suffers force to poise thereby, achieve the goal of sealing of body of build by laying bricks or stones and stability.

 

Iron mouth area is fireproof material:

   Area of mouth of iron of past blast furnace basically uses brick of stone of line of argillaceous brick, tall aluminous brick, silicon and large carbon brick, but of these a few kinds of bricks fight alkalescent, be able to bear or endure flake the gender is mixed the sex that fight broken bits is bad, large carbon brick fights oxidisability bad. And near future development goes ASC brick, use result shows its performance is better.    

Crucible, hearth uses fireproof data

Liner erodes a reason to reach to be able to bear or endure the basic function of material asks:

Erode a reason	To the performance demand of fireproof material
Corrode of frit of 1. molten iron and permeate 2. molten iron is circumfluent erode erode 3. alkali metal is eroded The destruction of 4. thermal stress action	It is good that 1. fights corrode of molten iron frit, impervious to appear a gender 2. thermal conductivity is good It is good that 3. fights alkali metal aggressivity 4. porosity is low, small aperture sex

 Above of taphole of body of crucible sidewall build by laying bricks or stones is eroded action by drossy, iron layer ” dies for ” under taphole, suffer molten iron for a long time to immerse, be eroded circumfluently in the boundary of crucible wall and hearth by molten iron action. Because body of this requirement build by laying bricks or stones has the good broken bits that fight iron, molten iron,erode ability and fight machinery to erode ability.

 At present crucible of big, medium-sized blast furnace, hearth uses home mostly carbolic brick and carbolic brick - cup of pottery and porcelain is compound crucible two kinds.