What are phosphate and the function that tall aluminous brick combines?

Phosphate combines tall aluminous brick, it is the blame that a kind of heat treatment makes bakes bricks, it is good to have wearability, commonly used at mouth of condenser, kiln, turn kiln transfers belt and cooling zone.


Phosphatic brick is dry base manage and technology measure. Do not burn tall aluminous brick (phosphate of the following abbreviation brick) basically use at cement industry. In recent years, as the work up of the market, the sales volume of phosphatic brick increases ceaselessly. The characteristic that manufactures technology because of phosphatic brick is: Raw material, mix beforehand, tired makings, mix, heat treatment, the company still does not have fixed product line at present, thrust deep into the enemy forces has production in each workshops. So, reasonable and harmonious the production between each working procedure and establish reasonable craft parameter, want to making sure quality and delivery time are attached most importance to especially. 50% what do heat treatment craft to take manufacturing time, original dry law and heat treatment system restrict production, product quality is not stable. In producing practice, the craft parameter that adjusts these two working procedure already became a problem that solves urgently. With special type alumina clinker is main raw material, add right amount phosphoric acid aqueous solution, through be being mixed beforehand, tired makings, mix, shape, the labour such as dry, heat treatment is made. Phosphoric acid itself does not have caking property, when the neuter oxide that waits for raw material when it and special type alumina is united in wedlock, after phosphate is united in wedlock
(Hydrogen of H2PO4)3) phosphoric acid is aluminous [(HPO4)3] thinks bases is commonly [Al(H2PO4)3] . Because it is OK below normal temperature dissolve at water, be used to when it so when making compound, it still can maintain plasticity for a long time, but be heated when it when constant temperature, aluminium of acidity phosphoric acid can turn Jiao Lin into acid aluminium and slant phosphoric acid is aluminous, can produce aggregate reaction next. Slant phosphoric acid aluminous polymer [the temperature of 400 ℃ above issues Al(PO3)3] consist in, the formation as a result of this kind of new-style compound, polymerization and form stronger felt action at the same time, make its gain strength. When temperature is elevatory, slant phosphoric acid aluminium also can produce catabolism. AlPO4 and P2O5, P2O5 and Al2O3 also can form AlPO4, increase the strength that integrates system. Accordingly, phosphatic brick has strength the characteristic with tall, good wearability. The phosphate after technology measure shapes contains 4%5% inside bricky body. Because be the moisture of % , so brick must dry, increase mechanical strength, be helpful for carrying, the operation of kiln, assure the exterior quality of the product, according to the manufacturing condition of the company, the regulation is dry in channel desiccator, before the brick enters oast must natural and dry, dry time is in 12h above, the temperature that enters pit is 60? 80 ℃ , the temperature of discrepancy kiln is 110? 130. Temperature, dry time is not less than 48h, dry hind rudimental moisture ≤ 1% ; Heat treatment is in convert gas undertake inside the pit pouring blaze that makes fuel, loading of kiln takes put down gently gently, accomplish level off, stable, straight, loose brick to pull seam, take course having fire. What characteristic does phosphatic brick have? Phosphatic brick is a kind of when in recent years development rises new-style and fireproof material, use phosphatic union to burn aluminous collect material, machine pressing shapes, use chroma to serve as bond for the phosphoric acid solution of 42.5%-50% . The brick that uses phosphoric acid aluminium to make bond be made is phosphatic wear-resisting brick. Two kinds of afore-mentioned bricks all are not fired brick, al2O3 content is about 80% , have high temperature resistant, anti-corrosive, be able to bear or endure urgent cold heat, wear-resisting, be able to bear or endure the advantage such as high strenth, but hot conductivity is taller. Phosphatic brick is applied to firing belt, phosphatic wear-resisting brick applies to cooling zone and the extreme that exothermic reaction is taken and divide ungird. Phosphatic brick is replaced to be tall aluminous brick in cement industry, be used extensively. 2.77g/cm3 of phosphatic brick density. After 500 ℃ are handled, compressive strength is 105 million handkerchief; 500 ℃ thermal shock 63.67 million handkerchief; 1000 ℃ thermal shock 16.48 million handkerchief. Bear bate temperature is in 0.6% 1325~1440 ℃ is when be out of shape, 4% be when be out of shape, 1495? 1550 ℃ . 500 ℃ are 1.849; 800 ℃ are 1.777; 1000 ℃ are 1.748; 1300 ℃ are 1.91. Smooth soaking coefficient of expansion (10~8/ ℃ ) : 500 ℃ 6.24; 1000 ℃ 7.25; 1300 ℃ 6.53. Thermal shock stability can bear 100 times in 1100 ℃ water-cooling.
Because producing phosphatic brick while, firing bricky production controls original craft parameter very hard also at the same time, cause dry car turnover not free, the influence shapes the normal production of craft, time of dry heat treatment is long, influence date of delivery. Obligate of path of the kiln in heat treatment process is undeserved, temperature is high, bring about kiln to carry adobe on the head excessive burn (erubescent) , bottom adobe is excessive burn (blacken) , dropped product percent of pass greatly. The working principle of the dry fundamental according to phosphatic brick and channel desiccator, kiln pouring blaze, undertook improvement to partial craft parameter. Channel desiccator uses refluent and dry principle commonly, the air current with low, big humidity contacts the brick with the high moisture content that enters desiccator and temperature to produce waste product not easily, dry when having certain level, the moisture in the brick is little, encounter temperature right now the hot air stream with small switch of tall, carry can accelerate dry process, phosphatic brick contains the moisture content of 4%5% , cannot enter channel desiccator directly. Otherwise, in dry process (the moisture) in main eduction brick, because be mixed by the concussion of high temperature air current,heat inhomogenous, form quick inhomogenous catchment, especially after bricky surface is apparently sclerotic, the stress effect that in-house and quick catchment produces brings about the surface to produce crackle, because this must be in in air after natural and dry period of time,ability can enter channel desiccator. Of phosphatic brick dry should use microtherm gale to measure dry way. Microtherm is helpful for slow and even catchment, avoid bricky appearance inchoate sclerosis; Large wind force is helpful for evaporating, take away moist air, improve dry efficiency. Manufacturing practice makes clear, natural and dry efficiency can enter channel desiccator.
Chimney is furnace of kiln of a kind of intermittent type, as a result of the attraction of chimney, force the smoke that comes out from fire box to pass product, aperture suction internal heat, raise flue to enter advocate flue, enter atmosphere through chimney, the air current inside kiln is used pour blaze means by what go up and fall. In microtherm phase, inside kiln conduct heat means basically passes convection to deliver a product through heating up smoke, product itself delivers quantity of heat the center from the surface through not steady heat conduction pattern. The heat treatment temperature of phosphatic brick is 500? 600 ℃ , accordingly, reasonable installation kiln, adjust the height of the fire-wall inside kiln, make the air current inside kiln smooth, reach the temperature inside kiln even, also facilitate of each temperature limits warm up, the kiln lukewarm control in heat preservation process, the setting suction in kiln bottom the action of igneous aperture is smoke evacuation, the size of its gross area and distributing, the operation to the fire-wall inside kiln is controlled and the temperature uniformity of face of truncat of the water inside kiln has very big concern. If gross area is too large, air current can run very quickly from aperture suction internal heat, quantity of heat cannot deliver a product adequately, quantity of heat is used poorer, use up taller, the quantity of heat inside kiln is controlled not easily; If gross area is too small, the high temperature inside kiln spends not easy control; If gross area is too small, fall in actual condition.
Flow inside kiln to make there is enough hot air stream inside kiln, prevent local brick excessive combustion, achieve brick the purpose of sufficient heat treatment, the size of the width that the suitable space, distance between brick, brick needs between a wall with flues for space heating of crotch of brick and kiln top, door, brick also must proper. Can see from 2.1 medium fundamental, the intensity after phosphatic brick heat treatment depends on phosphoric acid gathers aluminously and response rate, what need temperature to be in 300 ℃ above. Accordingly, when temperature under 300 ℃ when, adobe can rise appropriately heat speed, in order to ensure the free water of the remain in adobe and air adsorbed water do not have crackle.
The combustion in process of phosphatic brick heat treatment holds oppose product quality to have very big effect. Besides be operated correctly according to temperature system, still need to assure the pressure inside kiln and atmosphere. Accordingly, be necessary reasonable adjust flashboard and gas and airy scale, in order to satisfy requirement. Microtherm phase (0200 ℃ ) the free water that basically is the remain in eliminating adobe and air adsorbed water. Flashboard should be opened, in order to increase the attraction of chimney, take away water as soon as possible. In lukewarm phase (200500 ℃ ) basically be aluminium of anxious phosphoric acid generate and slant the aggregate reaction of phosphoric acid aluminium. Flashboard can be reduced appropriately, so that dominate pit better lukewarm, make reaction undertakes adequately; Heat preservation phase should reduce flashboard, raise temperature of the bottom inside kiln, make the temperature inside whole kiln agrees equably. Stop flashboard is opened after fire, kiln Wen Jiang comes wicket is opened after 300 ℃ , make kiln lukewarm drop quickly, leave pit as soon as possible. In whole warm up in the process, the temperature inside kiln, warm up speed, atmosphere, pressure is in produce change, because this needs to move the position of solar term atmosphere and flashboard meticulously, make heat treatment undertakes in small oxidation atmosphere.