In aluminous smelt, the equipment such as rotary kiln, electrobath and fusion furnace needs specific fireproof data to resist high temperature, chemistry is eroded and the element such as mechanical concussion. For example, in rotary kiln, use tall aluminous brick and magnesian chromic brick to serve as main fireproof material, and in electrobath, need to choose appliance to have good the material that fights oxidation function, if nitrogen changes the carbonization silica brick of silicon union. To fusion furnace, need considers to fight aluminous fluid and magnesian steam to erode, fight wear away and fight the character such as thermal shock, because this chooses,want to consider these factors integratedly when fireproof material.
As the ceaseless progress of the development of aluminous industry and equipment technology, fireproof material also is innovating ceaselessly and improve, in order to suit more efficient, more the manufacturing demand of environmental protection.
Nonferrous metal smelt basically includes a few fields: The aluminous smelt, cupreous smelt, plumbic smelt, zincic smelt, smelt of nickel, Jin Heyin, we introduce one by one the fireproof data that place of these nonferrous metal smelt require, the product that joins my company has detailed introduction.
In production of global nonferrous metal, produce per year a quantity aluminously to exceed other nonferrous metal far. The fireproof material gross that the fireproof material that aluminous industry uses up every year uses up than smelt of copper, lead, zinc is gotten greatly even much. The producer type of metallic aluminium uses two paces to secure a law: Above all, wet make from inside bauxite take alumina; Next, it is raw material with industrial alumina, use frit salt electrolysis to produce metallic aluminium. The heat of high temperature kiln that uses in producing a course has furnace of aluminium of electrobath of salt of rotary kiln, frit, frit to wait.
The aluminous fireproof material inside industrial furnace can be used up a lot of. Because make,this is when taking Al2O3, the basic material in stock can eat the fireproof stuff in rotary kiln badly. In aluminous fusion process, although metallic aluminium also has below inferior temperature very strong permeate ability. Once infiltration brick is medium, it can react with SiO2, bring about Si element by reductive, destroyed the structure of fireproof material, bring about lining to produce degenerative layer, become loose, flake and damage. React equation is: 3SiO2 + 4A1, 2A12O3 + 3SiO2.
Accordingly, cannot use the material building furnace of equipment of metallic aluminous fusion as the fireproof material that contains SiO2. Generally speaking, the fireproof data that is used at aluminous industry furnace besides tall aluminous brick, connect regular meeting to introduce carbolic simple product.
The rotary kiln that fireproof data uses in alumina production is current, when our country produces alumina, basically use agglomeration law and associated method these two kinds of methods, because,this basically is of raw material supply. To the processing process of bauxite, include normally dry and tender burn, the link such as the roast of hydroted alumina, and most factory use rotary kiln will have these technology. In recent years, although was introduced,flow to voice turns roast equipment and gain ground use, but in a few old plants, rotary kiln still holds quite large proportion.
Rotate kiln is the kiln heat that is used at grog of to calcine alumina. In alumina production, after making up aluminous earth, soda ash and lime in proportion above all, load rotate in kiln, the high temperature that passes 1200~1300 ℃ gives heat after fire, make hydroted alumina and mother solution via proper processing again; Put hydroted alumina rotate in kiln, to calcine can be finished below the high temperature of 1200 ℃ . Rotate the to calcine process inside kiln is such: High temperature blaze and stock move reversely inside furnace. Hydrous the hydroted alumina of the oar of raw material of alkaline lime aluminous earth of 40% or hydrous 12% ~ 18% is joined by kiln end, course low temperature is dry dehydration, heat, after high temperature to calcine, from kiln head discharge, high temperature gas flows to kiln end by kiln head. Accordingly, the cent inside kiln is warm-up area and area of high temperature to calcine. Heat to avoid to be in and the oar appears to expect felt kiln line increases in to calcine process conduct heat process, still set chain between fireproof material brick, stock of ceaseless in whirligig stroke and line brick, affected the service life of kiln line. The whirl that uses in the production of alumina kiln is by soldering armor plate canister system is become, interior enclothes fireproof material. This kind of fireproof material is in harsh working environment to fall, working requirement is very slashing. It needs to have the following character: Right alkaline erode have very strong fight a gender; Can work for long below the high temperature of 1200~1300 ℃ , won't damage; Can bear the impact that changes load; Can resist of charging erode; Can resist of high temperature air current erode. Rotate the fireproof data that kiln place uses basically is tall aluminous brick and magnesian chromic brick, and microtherm oast uses clay brick to serve as liner.
The whirl that alumina production uses fireproof material detailed sees kiln watch 1.
Current, aluminous industry uses indeterminate form extensively fireproof material, be worn away by high temperature the influence with thermal shock stress, the kiln mouth of rotary kiln is very incidental be out of shape and damage; Take in the transition of alumina grog kiln, environmental temperature is between 400~1000 ℃ , get alkalescent corrode and mechanical damage (shake, ill-natured) serious effect, liner classics regular meeting falls off. Steel fiber increases pouring makings the place such as end of mouth of the warm-up tape that also is used in rotary kiln, kiln, kiln and cooling machine.
Hydroted alumina roast is a working procedure that produces alumina fine, main purpose is the moisture in filter cake of eliminate hydroted alumina and crystallization water, at the same time translate into of one part β alumina α alumina. Country is at present major alumina manufacturer already part or begin those who introduce completely to use shed voice to turn roast equipment. Shed voice to change roast equipment to include to shed voice to change show furnace of fast roast furnace, circular fluid-bed roast, suspension roast heat this 3 sort, although what use fireproof material differs somewhat, but use indeterminate form generally fireproof material (be like fireproof and plastic or pouring makings) , occupy the 50%~70% of dosage of total fireproof material. Shed voice to change the indeterminate form that shows place of fast roast furnace to use fireproof material is introduced from Germany entirely, and the fireproof material of furnace of circular fluid-bed roast is produced for home entirely.
Furnace of roast of alumina gas in suspension is a kind of device that uses to calcine hydroted alumina technically, its craft and automation level are very high. Roast process undertakes in high temperature the chamber of a stove or furnace, temperature is 1200 ℃ about, and be below high speed condition finish. In the meantime, because the alumina stock hardness of processing is big, liquidity is good, very strict to product quality requirement. The interfuse of any impurity will affect the performance of the product directly. Accordingly, fireproof material must have caustic of high temperature resistant, wear-resisting, high strenth, good thermal stability, in good condition whole sex and powerful sealing to wait for a characteristic. Electrobath is the crucial equipment that produces aluminium, it is rectangular steel casing normally, inner lining has charcoal brick. The pensile charcoal in relief Ji inside groove, bottom is shade Ji. Change aluminous, fluorine to change the melt material such as lithium to serve as electrolyte with cryolite, fluorine, fuse Al2O3 below about 970 ℃ , ionization falls in the action of electric field force, go to the aluminous deposit that recover from an illness on bottom shade Ji, and in relief Ji gives off oxygen and CO2 of charcoal reaction generation or CO. Electrochemistry reacts the quantity of heat that release maintained electrobath and aluminium to be in fused condition, fixed from aluminous fluid of the eduction inside groove, add the alumina of certain amount and cryolite; Electroanalysis temperature is between 900~1000 ℃ . Electrobath uses charcoal piece to come normally compose builds bottom exercise layer. However, because carbon and natrium happen to react and form new compound, bring about bricky line structure to become loose, intensity drops, charcoal piece occurrence break. Subsequently, electrolyte and aluminous fluid can be entered along break, below high temperature aluminium and carbolic reaction produce inattentive carbolic compound, make break expands thereby, cause electrobath trough eventually housing is out of shape and liner is eroded badly, shorten service life. Accordingly, to solve this problem, the shade Ji material of electrobath bottom land already the instead of brick of carbon of the shape that be not brilliant from before half graphitization carbon brick or graphitization carbon brick. As a result of,the damage of line of wall of aluminous electrobath inside basically is the following element: Air introduces to bring about material oxidation between steel casing and bricky line; Erode in what sodium and aluminous juice are turned below high temperature by cryolite, fluorine; What by fuse-element flow brings is erosive; Temperature wave motion and heat bilge cold shrink the thermal stress that cause.
The sidewall of aluminous electrobath uses amorphous charcoal all the time piece with black lead the data such as charcoal piece, the defect of key of this kind of data is to fight oxidation function poorer, intensity is inferior. Do not oxidize to assure sidewall and have taller resistance, sidewall forward part or use development of SiC material direction entirely. Good choice is the carbonization silica brick that nitrogen changes silicon to be united in wedlock. This kind of brick has exceedingly good high temperature mechanical function and good thermal conductivity, inside forms condensation broken bits easily; Resistor rate is old, reduce loss of parietal electric current; The data oxidizes not easily; The fuse-element such as rock of fluid, as won't pure as aluminium ice produces reaction; Mechanical intensity is high, still can reduce line brick thickness considerably, add the dimension of electrobath, maintain operation stability. When using charcoal brick originally for instance, side wall ply is about between 200~400mm, after using nitrogen to change the carbonization silica brick that silicon combines, side wall ply needs 75mm only. The layer of lower part obstacle of bottom chamfer.
Electroanalysis in aluminium in production, the shade Ji material that sodium and fluorine turn the vapour of sodium and liquid state to be able to traverse bottom land enters the thermal insulation below. After fluorine was being added to change sodium inside thermal insulation, raised heat conduction rate, make the thermal efficiency of electrobath drops, working circumstance is exasperate, till groove child damaged. The " of " barrier layer below shade Ji material is a kind of clip is between shade Ji fireproof material and insulation material, can prevent the material layer that electrolyte permeates, have good heat preservation function at the same time. A kind new-style " barrier layer " material dry type prevented ooze layer to get applied extensively at present. Use fireproof material to make steel-making furnace and holding furnace.
Primitive aluminium piece heat with useless old aluminium fused and alloy is changed use the reflection type that secure or tilts to light furnace of combustion of gas or fuel normally, also can choose resistor reverberator or inductive type forge. Although the fused temperature of aluminous fluid and aluminium alloy in fusion furnace needs 700〜800 ℃ only, but the magnesium in aluminium and its alloy, silicon very lively, easy with fireproof material medium certain part produces reaction, cause fireproof material damage. Of aluminous fusion furnace corrode destroying a mechanism basically is: Aluminous fluid is easy infiltration is fireproof data is inside; The alloying element in aluminium and its alloy has powerful reductive capacity to certain oxide, and cause oxidation is reductive reaction has acuteness radiative quality. Among them, a few alloying element have higher evaporate steam pressure like magnesium, its steam is permeated more easily than aluminous fluid into fireproof material in. After entering these fireproof data, these alloying element immediately are oxidized, bring about fireproof material to corrode eventually, the structure is mixed loose damage.
In the fusion process of large aluminous forge, because put aluminium on ingot and alloy continuously, aluminous ingot and those who add up to bullion to be caused to forge mouth, hearth and furnace wall bump and wear away very serious; Aluminous ingot is added with what add up to bullion, the element such as the wave motion of the temperature inside the eduction of aluminous fluid, furnace may bring about fireproof material liner to produce thermal shock to mar.
The heat-insulating material of aluminous fusion reverberator must be had fight enter aluminous fluid and magnesian steam property, have at the same time fight goodly wear away and fight thermal shock character. The part that lining contacts aluminous fluid chooses Al2O3 content to be the tall aluminium brick of 80%〜85% normally; When fusion tall bullion belongs to aluminium, can choose Mo Laishi brick or corundum brick. Be corroded to sufferring easily and tatty area, if hearth brae is mixed,load point of useless old aluminous stuff, use nitrogen changes the carbonization silica brick that silicon combines. Serious to sufferring aluminium fluid to erode part, mix like chamfer drifting aluminium mouth giving aluminium, general meeting chooses to be united in wedlock oneself or nitrogen changes the carborundum brick that silicon combines, also can use wrong stone brick to make liner. When be being used at solving a problem of aluminous mouth block, the proposal chooses the fireproof fiber after vacuum mould. And to the lining that does not contact with aluminous fluid, general meeting chooses sex of clay brick, clay fireproof and pouring expect or fireproof but plastic. The liner of chamfer drifting aluminium uses carborundum brick normally, also can choose silica brick of electric frit bubble to undertake prefab.
Current, the amplification as dimensions of frit aluminous furnace needs with what aggrandizement takes exercise, high strenth fights aluminium to permeate pouring the fluid fighting aluminium that because its are exceedingly good,expects and magnesian steam invade a function, showed the respect such as good wear-resisting and heat-resisting concussion function to get applied extensively.
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